阅读说明：本技术 缓冲器 (Buffer device ) 是由 山下干郎 品田亮 于 2020-01-15 设计创作，主要内容包括：具有：设于形成于活塞(18)的第一通路(72、92)且产生阻尼力的第一阻尼力产生机构(41、42)；以及第二阻尼力产生机构(173、183),设于配置于一方的室(20)的环状的阀座部件(105),设于与第一通路(72、92)并列的第二通路(172、182),产生阻尼力,第二阻尼力产生机构(173、183)具备：设于在阀座部件(105)形成的第二通路(172、182)的一侧的第一副阀(181)以及在另一侧设置的第二副阀(171)；以及具有外侧筒部(124)与底部(122)的有底筒状的帽部件(108),帽部件(108)在底部(122)的内周侧形成能够插入活塞杆(21)的内侧筒部(126),收纳有第二阻尼力产生机构(173、183)的至少一部分。(Comprising: a first damping force generation mechanism (41, 42) that is provided in a first passage (72, 92) formed in the piston (18) and generates a damping force; and a second damping force generation mechanism (173, 183) that is provided in an annular valve seat member (105) disposed in one chamber (20), is provided in a second passage (172, 182) that is parallel to the first passage (72, 92), and generates a damping force, and the second damping force generation mechanism (173, 183) includes: a first sub-valve (181) provided on one side of a second passage (172, 182) formed in the valve seat member (105), and a second sub-valve (171) provided on the other side; and a bottomed cylindrical cap member (108) having an outer cylindrical portion (124) and a bottom portion (122), the cap member (108) having an inner cylindrical portion (126) into which the piston rod (21) can be inserted, formed on the inner peripheral side of the bottom portion (122), and housing at least a part of the second damping force generation mechanism (173, 183).)

1. A shock absorber is characterized by comprising:

a cylinder in which a working fluid is sealed;

a piston slidably provided in the cylinder and dividing the cylinder into two chambers;

a piston rod coupled to the piston and extending and protruding to the outside of the cylinder;

a first passage and a second passage through which a working fluid flows out from the upstream chamber to the downstream chamber in the cylinder by the movement of the piston;

a first damping force generating mechanism that is provided in the first passage formed in the piston and generates a damping force; and

a second damping force generating mechanism provided in the annular valve seat member disposed in one of the chambers, provided in the second passage parallel to the first passage, and generating a damping force,

the second damping force generation mechanism includes:

a first sub-valve provided on one side of the second passage formed in the valve seat member, and a second sub-valve provided on the other side; and

a cap member having a cylindrical shape with a bottom and having an outer cylindrical portion and a bottom,

the cap member has an inner tube portion formed on an inner peripheral side of the bottom portion and into which the piston rod is insertable, and houses at least a part of the second damping force generating mechanism.

2. The buffer of claim 1,

the second sub-valve and the valve seat member are housed in the cap member,

the valve seat member can be attached to the cap member with assistance from a seal member provided on the outer periphery.

3. The buffer of claim 1,

the second sub-valve and the valve seat member are housed in the cap member,

the outer periphery of the valve seat member is press-fitted into the cap member.

4. The buffer according to any one of claims 1 to 3,

a gasket is disposed between the bottom portion within the cap member and the second secondary valve.

5. The buffer according to any of claims 1 to 4,

the cap member includes a first cap member having the outer cylinder portion and the bottom portion, and a second cap member forming the inner cylinder portion.

6. The buffer according to any one of claims 1 to 5,

the cap member is formed by press forming.

7. The buffer of any of claims 1 to 6,

in a region where the piston speed is low, the second damping force generation mechanism is opened with the first damping force generation mechanism closed,

in a speed region where the piston speed is higher than the low speed, both the first damping force generation mechanism and the second damping force generation mechanism are opened.

8. The buffer according to any of claims 1 to 7,

with regard to the second damping-force generating mechanism,

the valve seat member is provided in the cap member, the first sub-valve is provided in one of the chambers, the second sub-valve is provided in a cap chamber between a bottom of the cap member and the valve seat member,

in the second passage, a throttle portion is disposed on an upstream side or a downstream side of the flow of the first sub valve opening valve.

9. The buffer of any of claims 1 to 6,

the second damping-force generating mechanism includes:

a cylindrical guide member provided on the piston rod and having a guide port on a side wall thereof;

a stopper member rotatably fitted in the guide member, the stopper member having a stopper port on a side wall thereof, the stopper port facing the guide port; and

and a driving unit which drives the stopper member.

Technical Field

The present invention relates to a buffer. The present application claims priority based on application No. 2019-032704 filed in japan on 26.2.2019, the contents of which are incorporated herein by reference.

Background

A shock absorber having two valves that open in the same stroke is disclosed (see, for example, patent documents 1 to 3).

Documents of the prior art

Patent document

Patent document 1 Japanese patent laid-open No. 2009-287763

Patent document 2 Japanese patent laid-open publication No. 2013-204772

Patent document 3 Japanese patent laid-open publication No. 2018-076920

Disclosure of Invention

Problems to be solved by the invention

It is required to improve the productivity in the buffer.

Accordingly, an object of the present invention is to provide a shock absorber capable of improving productivity.

Means for solving the problems

One aspect of a buffer of the present invention includes: a first passage and a second passage through which the working fluid flows out from a chamber on an upstream side to a chamber on a downstream side in the cylinder by the movement of the piston; a first damping force generating mechanism that is provided in the first passage formed in the piston and generates a damping force; and a second damping force generating mechanism provided in the annular valve seat member disposed in one of the chambers, provided in the second passage parallel to the first passage, and configured to generate a damping force, the second damping force generating mechanism including: a first sub-valve provided on one side of the second passage formed in the valve seat member, and a second sub-valve provided on the other side; and a cap member having a bottomed cylindrical shape and an outer cylindrical portion and a bottom portion, the cap member having an inner cylindrical portion into which the piston rod is insertable, the cap member accommodating at least a part of the second damping force generation mechanism, the inner cylindrical portion being formed on an inner peripheral side of the bottom portion.

Effects of the invention

According to the buffer, the production performance can be improved.

Drawings

Fig. 1 is a sectional view showing a shock absorber according to a first embodiment of the present invention.

Fig. 2 is a partial sectional view showing a periphery of a piston of a shock absorber according to a first embodiment of the present invention.

Fig. 3 is a partial sectional view showing the periphery of a throttle portion of a damper according to a first embodiment of the present invention.

Fig. 4 is a partial sectional view showing a sub-assembly such as a cap member and a seat member of a shock absorber according to a first embodiment of the present invention.

Fig. 5 is a partial sectional view showing the periphery of a piston of a damper according to a second embodiment of the present invention.

Fig. 6 is a partial sectional view showing the periphery of a piston of a shock absorber according to a third embodiment of the present invention.

Fig. 7 is a partial sectional view showing a periphery of a piston of a damper according to a fourth embodiment of the present invention.

Fig. 8 is a partial sectional view showing a periphery of a piston of a shock absorber according to a fifth embodiment of the present invention.

Fig. 9 is a partial sectional view showing a periphery of a piston of a shock absorber according to a sixth embodiment of the present invention.

Detailed Description

[ first embodiment ]

A first embodiment of the present invention will be described with reference to fig. 1 to 4. For convenience of explanation, the upper side in the drawings is referred to as "upper" and the lower side in the drawings is referred to as "lower".

As shown in fig. 1, a shock absorber 1 according to a first embodiment is a so-called multi-tube hydraulic shock absorber, and includes a cylinder 2 in which an oil liquid (not shown) as a working fluid is sealed. The cylinder 2 includes a cylindrical inner tube 3 and a bottomed cylindrical outer tube 4 having a larger diameter than the inner tube 3 and formed concentrically so as to cover the inner tube 3. In the cylinder 2, a liquid reservoir 6 is formed between the inner tube 3 and the outer tube 4.

The outer cylinder 4 includes a cylindrical trunk member 11 and a bottom member 12 fitted and fixed to a lower side of the trunk member 11 and closing a lower portion of the trunk member 11. A mount ring 13 is fixed to the bottom member 12 at an outer position opposite to the trunk member 11.

The damper 1 includes a piston 18 slidably provided inside the inner tube 3 of the cylinder 2. The piston 18 defines two chambers, i.e., an upper chamber 19 as one cylinder inner chamber and a lower chamber 20 (one chamber) as the other cylinder inner chamber, in the inner cylinder 3. In other words, the piston 18 is slidably provided in the cylinder 2 to divide the cylinder 2 into an upper chamber 19 on one side and a lower chamber 20 on the other side. Hydraulic fluid as a working fluid is sealed in the upper chamber 19 and the lower chamber 20 in the inner tube 3, and hydraulic fluid and gas as a working fluid are sealed in the reservoir 6 between the inner tube 3 and the outer tube 4.

The shock absorber 1 includes a piston rod 21, one end portion of the piston rod 21 in the axial direction is disposed inside the inner cylinder 3 of the cylinder 2 and is connected and fixed to the piston 18, and the other end portion extends and protrudes outside the cylinder 2. The piston rod 21 penetrates the upper chamber 19 and does not penetrate the lower chamber 20. Thus, the upper chamber 19 is a rod side chamber through which the piston rod 21 penetrates, and the lower chamber 20 is a bottom side chamber on the bottom side of the cylinder 2.

The piston 18 and the piston rod 21 move integrally. During an extension stroke of the shock absorber 1 in which the amount of protrusion of the piston rod 21 from the cylinder 2 increases, the piston 18 moves toward the upper chamber 19. In the compression stroke of the shock absorber 1 in which the amount of protrusion of the piston rod 21 from the cylinder 2 decreases, the piston 18 moves toward the lower chamber 20.

The rod guide 22 is fitted to the upper end opening sides of the inner cylinder 3 and the outer cylinder 4. The seal member 23 is fitted to the outside of the cylinder 2, i.e., to the upper side of the outer cylinder 4, with respect to the rod guide 22. The rod guide 22 and the seal member 23 are annular. The piston rod 21 is slidably inserted through the respective inner sides of the rod guide 22 and the seal member 23 and extends and protrudes from the inside to the outside of the cylinder 2. One end portion of the piston rod 21 in the axial direction is fixed to the piston 18 inside the cylinder 2, and the other end portion of the piston rod 21 protrudes outside the cylinder 2 via a rod guide 22 and a seal member 23.

The rod guide 22 supports the piston rod 21 to be movable in the axial direction while restricting its radial movement, and guides the movement of the piston rod 21. The seal member 23 is in close contact with the outer cylinder 4 at its outer circumferential portion and in sliding contact with the outer circumferential portion of the piston rod 21 that moves in the axial direction at its inner circumferential portion. Thus, the seal member 23 prevents the oil in the inner cylinder 3 and the high-pressure gas and oil in the reservoir 6 in the outer cylinder 4 from leaking to the outside.

The outer peripheral portion of the lever guide 22 is stepped such that the upper portion has a larger diameter than the lower portion. The rod guide 22 is fitted to the inner peripheral portion of the upper end of the inner cylinder 3 at the lower portion of the small diameter, and to the inner peripheral portion of the upper portion of the outer cylinder 4 at the upper portion of the large diameter. A base valve 25 that partitions the lower chamber 20 and the liquid reservoir 6 is provided in the bottom member 12 of the outer cylinder 4. The inner peripheral portion of the lower end of the inner cylinder 3 is fitted to the base valve 25. The upper end portion of the outer cylinder 4 is swaged radially inward to form a locking portion 26. The locking portion 26 and the rod guide 22 sandwich the seal member 23.

The piston rod 21 has a main shaft portion 27 and a mounting shaft portion 28 having a smaller diameter than the main shaft portion. The main shaft portion 27 of the piston rod 21 is slidably fitted to the rod guide 22 and the seal member 23, and the mounting shaft portion 28 is disposed in the cylinder 2 and connected to the piston 18 and the like. The end of the main shaft portion 27 on the side of the attachment shaft portion 28 is a shaft step portion 29 that extends in a direction orthogonal to the shaft. A pair of passage notches 30 extending in the axial direction are formed at the outer peripheral portion of the attachment shaft portion 28 at intermediate positions in the axial direction, and a male screw 31 is formed at a front end position on the opposite side to the main shaft portion 27 in the axial direction. The passage cutout 30 has a shape of a so-called double-sided width formed by cutting two positions of the attachment shaft portion 28 in the circumferential direction at 180 degrees in parallel in a planar manner.

In the shock absorber 1, for example, the piston rod 21 is disposed at an upper portion from a protruding portion of the cylinder 2 and supported by the vehicle body, and the mounting ring 13 on the cylinder 2 side is disposed at a lower portion and coupled to the wheel side. Conversely, the cylinder 2 side may be supported by the vehicle body, and the piston rod 21 may be connected to the wheel side.

As shown in fig. 2, the piston 18 includes a metal piston main body 35 connected to the piston rod 21, and an annular synthetic resin sliding member 36 integrally attached to an outer peripheral surface of the piston main body 35 and sliding in the inner tube 3.

The piston main body 35 has an annular main body portion 34. The body portion 34 is provided with a plurality of (only one in fig. 2 in a cross-sectional view) passage holes 37 that enable the upper chamber 19 and the lower chamber 20 to communicate with each other, and a plurality of (only one in fig. 2 in a cross-sectional view) passage holes 39 that enable the upper chamber 19 and the lower chamber 20 to communicate with each other. The piston main body 35 is a sintered product. The via holes 37, 39 are formed at the time of sintering. Alternatively, the passage holes 37, 39 are formed by drill cutting.

In the circumferential direction of the piston main body 35, a plurality of passage holes 37 are formed at equal intervals with one passage hole 39 therebetween, and constitute half of the passage holes 37 and 39. The plurality of passage holes 37 have a crank shape with two inflection points. One axial side (upper side in fig. 2) of the piston 18 of the plurality of passage holes 37 is open to the outside in the radial direction of the piston 18, and the other axial side (lower side in fig. 2) of the piston 18 is open to the inside in the radial direction of the piston 18.

A first damping force generating mechanism 41 that opens and closes the passage in the passage hole 37 and generates a damping force is provided on the lower chamber 20 side of the passage hole 37. The first damping force generation mechanism 41 is disposed on the lower chamber 20 side such that the passage in the plurality of passage holes 37 becomes an extension-side passage: when the piston 18 moves toward the upper chamber 19, in other words, during an extension stroke, the oil flows out from the upper chamber 19, which is the upstream side, toward the lower chamber 20, which is the downstream side. The first damping-force generating mechanism 41 provided for the passage in these passage holes 37 serves as an extension-side damping-force generating mechanism: the flow of the hydraulic fluid from the passage in the extension-side passage hole 37 to the lower chamber 20 is suppressed to generate the damping force.

The remaining half of the passage holes 37 and 39 are formed at equal intervals with one passage hole 37 in the circumferential direction of the piston main body 35.

The plurality of passage holes 39 are crank-shaped with two inflection points, and the other side in the axial direction of the piston 18 (the lower side in fig. 2) is open outward in the radial direction of the piston 18, and the one side in the axial direction of the piston 18 (the upper side in fig. 2) is open inward in the radial direction of the piston 18 on the other side.

A first damping force generating mechanism 42 that opens and closes the passage in the passage hole 39 and generates a damping force is provided on the upper chamber 19 side of the passage hole 39. The first damping force generation mechanism 42 is disposed on the upper chamber 19 side such that the passage in the plurality of passage holes 39 is a compression-side passage: when the piston 18 moves toward the lower chamber 20, in other words, during the compression stroke, the oil flows out from the lower chamber 20 on the upstream side toward the upper chamber 19 on the downstream side. The first damping force generation mechanism 42 provided for the passage in these passage holes 39 serves as a compression-side damping force generation mechanism as follows: the flow of the hydraulic fluid from the passage in the compression-side passage hole 39 to the upper chamber 19 is suppressed to generate the damping force.

The piston main body 35 has a substantially circular plate shape. An insertion hole 44 into which the attachment shaft portion 28 of the piston rod 21 is inserted is formed to penetrate axially through the center of the piston body 35 in the radial direction. The insertion hole 44 has a small-diameter hole 45 on one axial side into which the attachment shaft portion 28 of the piston rod 21 is fitted, and a large-diameter hole 46 on the other axial side having a larger diameter than the small-diameter hole 45. The piston 18 is fitted to the mounting shaft portion 28 in the small-diameter hole portion 45, and is positioned in the radial direction with respect to the mounting shaft portion 28.

An annular inner seat portion 47 protruding in the axial direction from the body portion 34 is formed at the end portion of the piston body 35 on the lower chamber 20 side in the axial direction, on the inner side in the radial direction of the piston body 35 than the opening of the passage hole 37 on the lower chamber 20 side. An annular valve seat portion 48 constituting a part of the first damping force generation mechanism 41 is formed on the end portion of the piston main body 35 on the lower chamber 20 side in the axial direction, so as to protrude in the axial direction from the main body portion 34 on the outer side in the radial direction of the piston main body 35 than the opening of the passage hole 37 on the lower chamber 20 side.

An annular inner seat portion 49 that protrudes in the axial direction from the body portion 34 is formed on the end portion of the piston body 35 on the upper chamber 19 side in the axial direction, on the inner side in the radial direction of the piston body 35 than the opening of the passage hole 39 on the upper chamber 19 side. An annular valve seat portion 50 constituting a part of the first damping force generation mechanism 42 is formed on the end portion of the piston main body 35 on the upper chamber 19 side in the axial direction, so as to protrude in the axial direction from the main body portion 34 on the outer side in the radial direction of the piston main body 35 than the opening of the passage hole 39 on the upper chamber 19 side.

The large-diameter hole portion 46 of the insertion hole 44 of the piston main body 35 is provided on the axial inner seat portion 47 side with respect to the small-diameter hole portion 45. The passage in the large diameter hole portion 46 of the piston main body 35 always communicates with the passage in the passage cutout portion 30 of the piston rod 21.

In the piston main body 35, the main body portion 34 radially outward of the seat portion 48 is stepped in height in the axial direction lower than the seat portion 48. The stepped portion of the piston main body 35 is provided with an opening on the lower chamber 20 side of the compression-side passage hole 39. Similarly, in the piston main body 35, the main body portion 34 radially outward of the seat portion 50 is stepped in height in the axial direction lower than the seat portion 50. The stepped portion is provided with an opening on the upper chamber 19 side of the extended-side passage hole 37.

The compression-side first damping-force generating mechanism 42 includes the valve seat portion 50 of the piston 18, and includes, in order from the piston 18 side in the axial direction, one disc 62, a plurality of (specifically, four) discs 63 having the same inner diameter and the same outer diameter, and a plurality of (specifically, two) discs 64 having the same inner diameter and the same outer diameter. On the opposite side of the disk 64 from the disk 63, one disk 65, one disk 66, and one annular member 67 are provided in this order from the disk 64 side. The disks 62 to 66 and the annular member 67 are made of metal, and each have a circular flat plate shape with a hole of a predetermined thickness into which the attachment shaft portion 28 of the piston rod 21 can be fitted. The disks 62 to 66 and the annular member 67 are fitted to the mounting shaft portion 28 and positioned in the radial direction with respect to the mounting shaft portion 28.

The disc 62 has an outer diameter larger than the outer diameter of the inner seat portion 49 of the piston 18 and smaller than the inner diameter of the valve seat portion 50, and is always in contact with the inner seat portion 49. The plurality of disks 63 have an outer diameter substantially equal to the outer diameter of the seat portion 50 of the piston 18, and can be seated on the seat portion 50.

The plurality of disks 64 have a smaller outer diameter than the outer diameter of the disk 63. The disc 65 has a smaller diameter than the outer diameter of the disc 64 and a smaller diameter than the outer diameter of the inner seat portion 49 of the piston 18. The disk 66 has an outer diameter larger than the outer diameter of the disk 64 and smaller than the outer diameter of the disk 63. The annular member 67 has a smaller diameter than the outer diameter of the disc 66 and a larger diameter than the outer diameter of the shaft step portion 29 of the piston rod 21. The annular member 67 is thicker and more rigid than the disks 62 to 66, and abuts against the shaft step 29.

The plurality of disks 63 and the plurality of disks 64 constitute a compression-side main valve 71 that can be separated from and seated on the seat portion 50. The main valve 71 is separated from the seat portion 50, communicates the passage in the passage hole 39 with the upper chamber 19, and suppresses the flow of the oil with respect to the seat portion 50 to generate the damping force. The deformation of the main valve 71 in the opening direction is restricted by the annular member 67 and the disk 66.

The passage between the main valve 71 and the valve seat portion 50, which appears when the valve is opened, and the passage in the passage hole 39 constitute a compression-side first passage 72 through which the hydraulic fluid moves toward the lower chamber 20 of the piston 18 and flows out from the lower chamber 20, which is the upstream side, to the upper chamber 19, which is the downstream side, in the cylinder 2. The first damping force generating mechanism 42 on the compression side that generates the damping force includes a main valve 71 and a valve seat portion 50. Thus, the first damping force generation mechanism 42 on the compression side is provided in the first passage 72. The first passage 72 is formed in the piston 18 including the seat portion 50, and the oil supply liquid passes therethrough when the piston rod 21 and the piston 18 move to the compression side.

Here, in the first damping force generation mechanism 42 on the compression side, a fixed throttle portion that communicates the upper chamber 19 with the lower chamber 20 even when they are in a contact state is not formed in either the valve seat portion 50 or the main valve 71 that is in contact therewith. That is, if the seat portion 50 and the main valve 71 are in a state of contact over the entire circumference, the compression-side first damping force generation mechanism 42 does not cause the upper chamber 19 and the lower chamber 20 to communicate with each other. In other words, the first passage 72 is not formed with a fixed throttle portion that constantly communicates the upper chamber 19 and the lower chamber 20, but is not a passage that constantly communicates the upper chamber 19 and the lower chamber 20. The first damping force generating mechanism 42 is in a valve-closed state when the piston rod 21 and the piston 18 move to the extension side, and does not pass the oil through the first passage 72.

The expansion-side first damping force generating mechanism 41 includes a valve seat portion 48 of the piston 18, and includes one disc 82 and a plurality of (specifically, five) discs 83 having the same inner diameter and the same outer diameter in order from the piston 18 side in the axial direction. A plurality of (specifically, three) disks 84 having the same inner diameter and the same outer diameter are provided on the side of the disk 83 opposite to the disk 82. The disks 82 to 84 are made of metal, each having a perforated circular flat plate shape with a certain thickness into which the mounting shaft portion 28 of the piston rod 21 can be fitted, and are positioned in the radial direction with respect to the mounting shaft portion 28 by being fitted into the mounting shaft portion 28.

The disc 82 has an outer diameter larger than the outer diameter of the inner seat portion 47 of the piston 18 and smaller than the inner diameter of the valve seat portion 48, and is always in contact with the inner seat portion 47. As shown in fig. 3, the disc 82 is formed with a cutout portion 88 that constantly communicates the passage in the passage hole 37 with the passage in the large diameter hole portion 46 of the piston 18 and the passage in the passage cutout portion 30 of the piston rod 21, from a position radially outward of the inner seat portion 47 to the inner peripheral edge portion.

The plurality of disks 83 have an outer diameter substantially equal to the outer diameter of the seat portion 48 of the piston 18, and can be seated on the seat portion 48. The disc 84 has a smaller diameter than the outer diameter of the disc 83 and the inner seat 47 of the piston 18.

The plurality of disks 83 constitute an extension-side main valve 91 that can be separated from and seated on the seat portion 48. The main valve 91 is separated from the seat portion 48, and thereby the passage in the passage hole 37 communicates with the lower chamber 20, and the flow of the hydraulic fluid to the seat portion 48 is suppressed to generate the damping force.

As shown in fig. 2, the passage between the main valve 91 and the valve seat portion 48, which appears when the valve is opened, and the passage in the passage hole 37 constitute an extended-side first passage 92 through which the hydraulic fluid flows from the upper chamber 19, which is the upstream side, to the lower chamber 20, which is the downstream side, in the cylinder 2 by the movement of the piston 18 toward the upper chamber 19. The first damping force generating mechanism 41 on the expansion side that generates the damping force is provided in the first passage 92 by including the main valve 91 and the seat portion 48. The first passage 92 is formed in the piston 18 including the seat portion 48, and allows the oil to pass therethrough when the piston rod 21 and the piston 18 move toward the extension side.

In the first damping force generation mechanism 41 on the expansion side, a fixed orifice portion that communicates the upper chamber 19 with the lower chamber 20 even when the seat portion 48 and the main valve 91 in contact therewith are not formed in either of these portions. That is, if the seat portion 48 and the main valve 91 are in the abutting state over the entire circumference, the extension-side first damping force generation mechanism 41 does not cause the upper chamber 19 and the lower chamber 20 to communicate with each other. In other words, the first passage 92 is not formed with a fixed throttle portion that constantly communicates the upper chamber 19 and the lower chamber 20, and is not a passage that constantly communicates the upper chamber 19 and the lower chamber 20. The first damping force generating mechanism 41 is in a valve-closed state when the piston rod 21 and the piston 18 move to the compression side, and does not pass the hydraulic fluid through the first passage 92.

On the side of the disks 84 opposite to the piston 18, a plurality of (specifically, two) disks 101 having the same inner diameter and the same outer diameter, through which the attachment shaft portion 28 of the piston rod 21 is inserted, a disk 102 having the same outer diameter as the disks 101, a valve seat member 105 having a seal member 103 on the outer circumferential side, a plurality of (specifically, two) disks 106 having the same inner diameter and the same outer diameter, a plurality of (specifically, two) disks 107 having the same inner diameter and the same outer diameter, a cap member 108, a disk 110, and an annular member 111 are provided in this order from the piston 18 side. The mounting shaft portion 28 of the piston rod 21 has a male screw 31 formed at a portion projecting on the opposite side of the piston 18 from the annular member 111. A nut 112 is screwed to the male screw 31. The nut 112 abuts on the annular member 111.

The disks 101, 102, 106, 107, 110, the valve seat member 105, the cap member 108, and the ring member 111 are all made of metal. The sealing member 103 is made of an elastic material such as rubber. The disks 101, 102, 106, 107, and 110 and the annular member 111 are each in the form of a perforated circular flat plate having a predetermined thickness into which the mounting shaft portion 28 of the piston rod 21 can be fitted, and are fitted to the mounting shaft portion 28 so as to be positioned radially with respect to the mounting shaft portion 28. Both the cap member 108 and the valve seat member 105 are annular and the mounting shaft portion 28 of the piston rod 21 can be inserted inside. The cap member 108 is fitted to the mounting shaft portion 28 of the piston rod 21, and is thereby positioned in the radial direction with respect to the mounting shaft portion 28.

The cap member 108 is an integrally formed product having a cylindrical shape with a bottom, and is formed by punching a metal plate having a predetermined thickness and plastically deforming the punched metal plate. The cap member 108 has a perforated circular flat plate-shaped bottom portion 122, a cylindrical outer tube portion 124 extending and protruding from the outer peripheral edge portion of the bottom portion 122 to one side in the axial direction of the bottom portion 122, an opening diameter-enlarging portion 125 expanding and protruding from the end edge portion on the opposite side of the bottom portion 122 in the axial direction of the outer tube portion 124 in the direction opposite to the bottom portion 122, and a cylindrical inner tube portion 126 extending and protruding from the inner peripheral edge portion of the bottom portion 122 to the same side as the outer tube portion 124 in the axial direction of the bottom portion 122.

The bottom 122, the outer tube 124, the opening expanding portion 125, and the inner tube 126 of the cap member 108 are coaxially arranged. The cross section of the surface of the opening expanding portion 125 including the center axis of the cap member 108 is arc-shaped. The axial length of the inner tube portion 126 is shorter than that of the outer tube portion 124, and the entire opening diameter-enlarged portion 125 is positioned on the opposite side of the inner tube portion 126 from the bottom portion 122 in the axial direction. The inner cylindrical portion 126 is formed with a chamfer 127 over the entire circumference at the outer peripheral edge of the end portion on the opposite side to the bottom portion 122 in the axial direction, and is also formed with a chamfer 128 over the entire circumference at the inner peripheral edge of the same end portion.

The cap member 108 can insert the piston rod 21 inside the inner tube portion 126 on the inner peripheral side of the bottom portion 122. The cap member 108 is disposed with the bottom portion 122 facing the direction opposite to the piston 18, and is fitted to the mounting shaft portion 28 of the piston rod 21 at the inner peripheral portion of the inner cylindrical portion 126. Thereby, the cap member 108 is positioned in the radial direction including the inner tube portion 126 with respect to the mounting shaft portion 28.

The valve seat member 105 has a substantially disk shape having an outer diameter smaller than the inner diameter of the outer cylindrical portion 124 of the cap member 108. The valve seat member 105 includes a main body portion 132 having a circular flat plate shape with a hole, in which a through hole 131 for inserting the mounting shaft portion 28 is formed at the center in the radial direction so as to penetrate in the thickness direction. The through hole 131 includes a small-diameter hole portion 129 on one axial side and a large-diameter hole portion 130 on the other axial side having a larger diameter than the small-diameter hole portion 129. The seat member 105 includes an inner seat portion 134, an intermediate seat portion 135, and an outer seat portion 136 in this order from the radially inner side of the main body portion 132 on the large diameter hole portion 130 side in the axial direction of the main body portion 132. The seat member 105 includes an inner seat portion 138 and a seat portion 139 in order from the radially inner side of the main body portion 132 on the side of the small-diameter hole portion 129 in the axial direction.

The inner seat 134 is annular and protrudes from the inner peripheral edge of the body 132 to one side in the axial direction of the body 132. The intermediate seat portion 135 is also annular and protrudes from an intermediate position in the radial direction of the main body portion 132 on the outer side of the inner seat portion 134 toward the same side as the inner seat portion 134 in the axial direction of the main body portion 132. The outer seat portion 136 is also annular and protrudes from the outer peripheral side in the radial direction of the main body portion 132 on the outer side of the intermediate seat portion 135 toward the same side as the inner seat portion 134 in the axial direction of the main body portion 132.

The inner seat 138 is also annular and protrudes from the inner peripheral edge of the body 132 to the opposite side of the inner seat 134 in the axial direction of the body 132. The inner seats 134 and 138 are through holes 131 formed radially inward. The seat portion 139 is also annular and protrudes from an intermediate position in the radial direction of the main body portion 132 on the outer side of the inner seat portion 138 toward the same side as the inner seat portion 138 in the axial direction of the main body portion 132. The intermediate seat portion 135 and the seat portion 139 have the same inner diameter and the same outer diameter.

In the main body portion 132, an inner passage hole 141 that penetrates the main body portion 132 in the axial direction is formed between the inner seat portions 134 and 138 and the intermediate seat portion 135 and the seat portion 139. The inner passage holes 141 are formed at equal intervals in the circumferential direction of the body 132. In the main body portion 132, an outer passage hole 143 penetrating the main body portion 132 in the axial direction is formed between the intermediate seat portion 135 and the outer seat portion 136 and radially outward of the seat portion 139. The outer passage holes 143 are arranged radially outward of the inner passage holes 141 in the main body portion 132, and a plurality of the outer passage holes are formed at equal intervals in the circumferential direction of the main body portion 132.

An annular seal groove 145 recessed radially inward is formed at an axially intermediate position in the outer peripheral portion of the body 132. A seal member 103 is disposed in the seal groove 145.

The seal member 103 is an O-ring and is fitted to the groove bottom surface formed by the cylindrical surface of the seal groove 145 over the entire circumference with interference.

The seat member 105 is accommodated in the cap member 108 by inserting the outer peripheral side into the body portion 132 into the outer tube portion 124 of the cap member 108 in a state where the inner seat portion 134, the intermediate seat portion 135, and the outer seat portion 136 are directed toward the bottom portion 122 side. In this state, the seal member 103 is fitted over the entire circumference with interference to the inner circumferential surface of the outer tube portion 124 of the cap member 108, and elastically deforms to seal the gap between the outer tube portion 124 and the body portion 132 of the valve seat member 105. At the same time, the valve seat member 105 is fitted to the inner tube portion 126 of the cap member 108 at the large-diameter hole portion 130 of the through hole 131 on the inner peripheral side. Thereby, the valve seat member 105 is positioned in the radial direction with respect to the inner cylindrical portion 126 of the cap member 108.

The cap member 108, the valve seat member 105, and the seal member 103 constitute a housing 147 in which a cap chamber 146 is formed. A cap chamber 146 is provided within housing 147 between bottom 122 of cap member 108 and valve seat member 105. A plurality of disks 107 and a plurality of disks 106 are disposed within the cap chamber 146. The intermediate seat portion 135 and the outer seat portion 136 of the seat member 105 are disposed on the cap chamber 146 side, and the seat portion 139 is disposed on the lower chamber 20 side. The housing 147 is disposed in the lower chamber 20 including the annular valve seat member 105. Valve seat member 105 partitions cap chamber 146 and lower chamber 20, and is provided to face both cap chamber 146 and lower chamber 20.

The disks 106 have an outer diameter substantially equal to the outer diameter of the outer seat portion 136 of the seat member 105, and an inner diameter equal to the outer diameter of the inner tube portion 126 of the cap member 108. The disks 106 are fitted at the inner circumferential portion to the outer circumferential portion of the inner cylindrical portion 126 of the cap member 108. Thereby, the plurality of disks 106 are positioned in the radial direction with respect to the inner cylindrical portion 126 of the cap member 108. The plurality of disks 106 are constantly in contact with the inner seat portion 134 and can be seated on the outer seat portion 136 and the intermediate seat portion 135. In each of the plurality of disks 106, a through hole 161 that penetrates in the axial direction is formed at an intermediate position in the radial direction between the inner seat portion 134 and the intermediate seat portion 135. The passage in the through hole 161 allows the passage in the inner passage hole 141 of the valve seat member 105 to always communicate with the cap chamber 146.

The disks 107 have a smaller diameter than the disk 106, and have an outer diameter substantially equal to the outer diameter of the inner seat 134 of the valve seat member 105 and an inner diameter equal to the outer diameter of the inner tube 126 of the cap member 108. The disks 107 are fitted at the inner periphery to the outer periphery of the inner cylindrical portion 126 of the cap member 108. Thereby, the plurality of disks 107 are positioned in the radial direction with respect to the inner cylindrical portion 126 of the cap member 108.

The disk 102 has an outer diameter substantially equal to the outer diameter of the seat portion 139 of the seat member 105. The disk 102 is always in contact with the inner seat portion 138 and can be seated on the seat portion 139. The disks 101 have an outer diameter substantially equal to the outer diameter of the disk 102, and are superposed on the disk 102 on the side opposite to the valve seat member 105.

As shown in fig. 3, in the disc 102, a cutout 165 that constantly communicates a passage in the inner passage hole 141 with a passage in the small-diameter hole portion 129 of the valve seat member 105 and a passage in the passage cutout 30 of the piston rod 21 is formed from a midway position inside the radial valve seat portion 139 and outside the inner seat portion 138 to the inner peripheral edge portion.

As shown in fig. 2, the cap chamber 146 is always communicated with the upper chamber 19 via the passage in the through hole 161 of the disk 106, the passage in the inner passage hole 141 of the valve seat member 105, the passage in the cutout 165 of the disk 102, the passage in the small-diameter hole portion 129 of the valve seat member 105, the passage in the passage cutout 30 of the piston rod 21, the passage in the large-diameter hole portion 46 of the piston 18, the passage in the cutout 88 of the disk 82, and the passage in the passage hole 37 of the piston 18.

The plurality of disks 106 constitute a sub-valve 171 (second sub-valve) that can be separated from and seated on the outer seat portion 136 and the intermediate seat portion 135.

The sub-valve 171 is provided in the cap chamber 146, and is separated from the outer seat portion 136 in the cap chamber 146, so that the passage in the outer passage hole 143 communicates with the cap chamber 146. Thus, the sub-valve 171 communicates the lower chamber 20 with the upper chamber 19 via the passage in the outer passage hole 143, the cap chamber 146, the passages in the through holes 161 of the plurality of disks 106, the passage in the inner passage hole 141, the passage in the cutout 165 of the disk 102, the passage in the small-diameter hole portion 129 of the valve seat member 105, the passage in the passage cutout 30 of the piston rod 21, the passage in the large-diameter hole portion 46 of the piston 18, the passage in the cutout 88 of the disk 82, and the passage in the passage hole 37 of the piston 18. At this time, the sub-valve 171 suppresses the flow of the hydraulic fluid with respect to the outer seat portion 136, and generates a damping force. The sub-valve 171 is an inflow valve that opens when the oil flows from the lower chamber 20 into the cap chamber 146 through the passage in the outer passage hole 143, and is a check valve that restricts the flow of the oil through the passage in the outer passage hole 143 from the cap chamber 146 to the lower chamber 20.

The passage in the outer passage hole 143, the passage between the sub-valve 171 and the outer seat portion 136 that appears when the valve is opened, the cap chamber 146, the passage in the through hole 161 of the disk 106, the passage in the inner passage hole 141 of the seat member 105, the passage in the notch portion 165 of the disk 102, the passage in the small-diameter hole portion 129 of the seat member 105, the passage in the passage notch portion 30 of the piston rod 21, the passage in the large-diameter hole portion 46 of the piston 18, the passage in the notch portion 88 of the disk 82, and the passage in the passage hole 37 constitute a second passage 172 through which the oil supply liquid flows out from the lower chamber 20 on the upstream side to the upper chamber 19 on the downstream side in the cylinder 2 by the movement of the piston 18 toward the lower chamber 20 side.

The second passage 172 serves as a compression-side passage: when the piston 18 moves toward the lower chamber 20, in other words, during the compression stroke, the hydraulic fluid flows out from the lower chamber 20 on the upstream side toward the upper chamber 19 on the downstream side. The second passage 172 includes a passage in the passage cutout 30 formed by cutting the piston rod 21, in other words, a part thereof is formed by cutting the piston rod 21.

The sub valve 171, the outer seat portion 136, the intermediate seat portion 135, and the cap member 108 are provided in a second passage 172 on the compression side, and the second passage 172 is opened and closed to constitute a second damping force generating mechanism 173 on the compression side that suppresses the flow of the hydraulic fluid from the second passage 172 to the upper chamber 19 to generate a damping force. In other words, the outer seat portion 136 and the intermediate seat portion 135 of the second damping force generation mechanism 173 are provided in the seat member 105. The sub-valve 171 constituting the second damping force generation mechanism 173 on the compression side is a sub-valve on the compression side.

The cap member 108 has a substantially constant thickness and is thicker than the disk 106 constituting the sub-valve 171. The bottom portion 122 is made more rigid than the disk 106 by forming an outer cylindrical portion 124 and an inner cylindrical portion 126 on both sides in the radial direction. Thereby, the bottom portion 122 of the cap member 108 abuts on the sub-valve 171 to restrict deformation thereof in the opening direction by a predetermined amount or more.

In the second passage 172, the passage in the notch portion 165 of the disc 102 becomes the throttle portion 176 throttled in the portion where the passage cross-sectional area is fixed, and the passage in the notch portion 88 of the disc 82 also becomes the throttle portion 175 throttled in the portion where the passage cross-sectional area is fixed. The chokes 175 and 176 are disposed downstream of the sub valve 171 in the flow of the hydraulic fluid when the sub valve 171 is opened and the hydraulic fluid flows through the compression-side second passage 172. In the second passage 172, a throttle 176 is disposed on the upstream side of the flow of the hydraulic fluid when the sub valve 171 is opened, and a throttle 175 is disposed on the downstream side. Further, only one of the chokes 175 and 176 may be provided in the second passage 172.

The second damping force generation mechanism 173 on the compression side is not provided with a fixed orifice portion that communicates the lower chamber 20 with the upper chamber 19 even when they are in a contact state, in any of the outer seat portion 136, the intermediate seat portion 135, and the sub valve 171 that is in contact with them. That is, if the outer seat portion 136 and the intermediate seat portion 135 are in a state of contact with the disc 106 over the entire circumference, the compression-side second damping force generation mechanism 173 does not communicate the lower chamber 20 with the upper chamber 19. In other words, the second passage 172 does not have a fixed throttle portion that constantly communicates the lower chamber 20 and the upper chamber 19, and is not a passage that constantly communicates the lower chamber 20 and the upper chamber 19. The second damping force generation mechanism 173 is in a closed state when the piston rod 21 and the piston 18 move to the extension side, and does not pass the oil through the second passage 172.

The second passage 172, which can communicate the compression side of the lower chamber 20 and the upper chamber 19, is arranged in parallel with the first passage 72, which is a passage that can communicate the compression side of the lower chamber 20 and the upper chamber 19. The first passage 72 is provided with a first damping force generating mechanism 42, and the second passage 172 is provided with a second damping force generating mechanism 173. Thus, the first damping force generation mechanism 42 and the second damping force generation mechanism 173, both of which are compression sides, are arranged in parallel.

The disks 84 have a smaller diameter than the outer diameter of the disk 101 and an outer diameter substantially the same as the outer diameter of the inner seat portion 138 of the valve seat member 105. The disk 110 has an outer diameter larger than the inner diameter of the bottom 122 of the cap member 108 and smaller than the outer diameter of the bottom 122. The annular member 111 has a diameter larger than the outer diameter of the disc 110.

The disk 102 and the disks 101 constitute a sub-valve 181 (first sub-valve) that can be separated from and seated on the seat portion 139. The disk 102 and the plurality of disks 101 are smaller in diameter than the outer diameter of the disk 106 and are more rigid than the disk 106. The sub valve 181 formed by the disk 102 and the disks 101 is also higher in rigidity than the sub valve 171 formed by the disks 106.

The sub-valve 181 is provided in the lower chamber 20 and is separated from the seat portion 139, whereby the upper chamber 19 communicates with the lower chamber 20 via the passage in the passage hole 37 of the piston 18, the passage in the cutout portion 88 of the disk 82, the passage in the large-diameter hole portion 46 of the piston 18, the passage in the passage cutout portion 30 of the piston rod 21, the passage in the small-diameter hole portion 129 of the valve seat member 105, and the passage in the cutout portion 165 of the disk 102. At this time, the sub-valve 181 suppresses the flow of the hydraulic fluid with respect to the seat portion 139 to generate the damping force. The sub-valve 181 is a discharge valve that opens when discharging the oil from the upper chamber 19 to the lower chamber 20, and is a check valve that closes to restrict the flow of the oil from the lower chamber 20 to the upper chamber 19.

The passage in the passage hole 37 of the piston 18, the passage in the cutout portion 88 of the disc 82, the passage in the large-diameter hole portion 46 of the piston 18, the passage in the cutout portion 30 of the passage of the piston rod 21, the passage in the small-diameter hole portion 129 of the valve seat member 105, the passage in the cutout portion 165 of the disc 102, and the passage between the sub-valve 181 and the valve seat portion 139 that occur at the time of opening the valve constitute a second passage 182 through which the oil supply liquid flows out from the upper chamber 19 that becomes the upstream side in the cylinder 2 to the lower chamber 20 that becomes the downstream side by the movement of the piston 18 to the expansion side. Here, the second passage 182 includes a passage in the inner passage hole 141 of the valve seat member 105, such as a passage in the notch portion 165 of the disk 102, a passage in the through hole 161 of the disk 106, and the cap chamber 146.

The second passage 182 is an extension-side passage: when the piston 18 moves toward the upper chamber 19, in other words, during the extension stroke, the hydraulic fluid flows out from the upper chamber 19, which is the upstream side, toward the lower chamber 20, which is the downstream side. The second passage 182 includes a passage in the passage cutout 30 formed by cutting the piston rod 21, in other words, a part thereof is formed by cutting the piston rod 21.

The sub valve 181 and the seat portion 139 are provided in the second passage 182 on the expansion side, and the second passage 182 is opened and closed to constitute a second damping force generation mechanism 183 on the expansion side that suppresses the flow of the hydraulic fluid from the second passage 182 to the lower chamber 20 to generate the damping force. In other words, the seat portion 139 of the second damping force generation mechanism 183 is provided in the seat member 105. The sub valve 181 constituting the second damping force generation mechanism 183 on the expansion side is a sub valve on the expansion side.

In the second passage 182, the passage in the notch portion 88 of the disk 82 also serves as the throttle portion 175 throttled in the portion where the passage cross-sectional area is fixed, and the passage in the notch portion 165 of the disk 102 also serves as the throttle portion 176 throttled in the portion where the passage cross-sectional area is fixed. The throttles 175, 176 are shared by the second passages 172, 182. The chokes 175 and 176 are disposed upstream of the sub valve 181 in the flow of the hydraulic fluid when the sub valve 181 is opened and the hydraulic fluid flows through the extension-side second passage 182. In the second passage 182, the orifice 175 is disposed on the upstream side of the flow of the hydraulic fluid when the sub valve 181 is opened, and the orifice 176 is disposed on the downstream side. The second passage 182 may be provided with only one of the throttles 175 and 176.

The throttle portion 175 is formed by cutting the disc 82 in contact with the piston 18 in the first damping force generation mechanism 41, and the throttle portion 176 is formed by cutting the disc 102 in contact with the valve seat member 105 in the second damping force generation mechanism 183.

The second damping force generating mechanisms 173 and 183 include a sub-valve 181 provided on one side of the second passage 172 partially formed in the valve seat member 105, a sub-valve 171 provided on the other side, a sub-valve 181 provided on one side of the second passage 182 partially formed in the valve seat member 105, and a sub-valve 171 provided on the other side. The sub valve 171, the outer seat portion 136, and the intermediate seat portion 135, which are formed of the plurality of disks 106 and constitute a part of the second damping force generation mechanism 173, are housed in the cap member 108, which is also a part of the second damping force generation mechanism 173, and the seat member 105 and the seal member 103 are also housed in the cap member 108. In other words, the sub-valve 171 including the plurality of disks 106, the valve seat member 105, and the seal member 103 are accommodated in the cap member 108. Further, at least a part of the second damping force generation mechanisms 173 and 183 may be housed in the cap member 108.

The disks 101 and 102 constituting the sub-valve 181 have higher rigidity than the disk 106 constituting the sub-valve 171, and the sub-valve 181 has higher rigidity than the sub-valve 171. Thus, the sub-valve 171 as an inflow valve from the lower chamber 20 to the cap chamber 146 has a lower valve opening pressure than the sub-valve 181 as a discharge valve from the second passage 182 to the lower chamber 20. The sub valve 181 is opened and closed independently of the sub valve 171.

The extension-side second damping force generation mechanism 183 does not have a fixed throttle portion that communicates the upper chamber 19 with the lower chamber 20 even when the seat portion 139 and the sub-valve 181 in contact therewith are in a contact state. That is, if the seat portion 139 and the sub valve 181 are in a state of contact over the entire circumference, the second damping force generation mechanism 183 on the expansion side does not cause the upper chamber 19 and the lower chamber 20 to communicate with each other. In other words, the second passage 182 is not formed with a fixed throttle portion that constantly communicates the upper chamber 19 and the lower chamber 20, and is not a passage that constantly communicates the upper chamber 19 and the lower chamber 20. The second damping force generating mechanism 183 is in a valve-closed state when the piston rod 21 and the piston 18 move to the compression side, and does not pass the hydraulic fluid through the second passage 182.

In the shock absorber 1, at least the upper chamber 19 and the lower chamber 20 are allowed to communicate with each other only through the first damping force generation mechanisms 41 and 42 and the second damping force generation mechanisms 173 and 183 as a flow through which the oil passes in the axial direction in the piston 18. Thus, the shock absorber 1 is not provided with a fixed orifice portion that constantly communicates the upper chamber 19 and the lower chamber 20 at least in a passage that passes through the oil liquid in the piston 18 in the axial direction.

The second passage 182 capable of communicating the extension sides of the upper chamber 19 and the lower chamber 20 is arranged in parallel with the first passage 92 capable of communicating the extension sides of the upper chamber 19 and the lower chamber 20, except for the passage in the passage hole 37 on the upper chamber 19 side. In the parallel portion, the first damping force generating mechanism 41 is provided in the first passage 92, and the second damping force generating mechanism 183 is provided in the second passage 182. Thus, the first damping force generating mechanism 41 and the second damping force generating mechanism 183, both of which are on the extension side, are arranged in parallel.

The second damping force generating mechanisms 173 and 183 include a valve seat member 105, a sub-valve 171 provided on one side of second passages 172 and 182 provided in the valve seat member 105, and a sub-valve 181 provided on the other side. The second damping force generation mechanism 173 of the second damping force generation mechanisms 173 and 183 includes a bottomed cylindrical cap member 108 forming the second passage 172. The sub valve 181 is provided on the lower chamber 20 side of the valve seat member 105, and the sub valve 171 is provided in the cap chamber 146 between the bottom portion 122 of the cap member 108 and the valve seat member 105.

As shown in fig. 1, the base valve 25 is provided between the bottom member 12 of the outer tube 4 and the inner tube 3. The base valve 25 includes a base valve member 191 that partitions the lower chamber 20 and the reservoir 6, a disk 192 provided below the base valve member 191, in other words, on the reservoir 6 side, a disk 193 provided above the base valve member 191, in other words, on the lower chamber 20 side, and an attachment pin 194 that attaches the disk 192 and the disk 193 to the base valve member 191.

The base valve member 191 is annular, and the mounting pin 194 is inserted through the center in the radial direction. The base valve member 191 is provided with a plurality of passage holes 195 through which the hydraulic fluid can flow between the lower chamber 20 and the reservoir 6, and a plurality of passage holes 196 outside the passage holes 195 in the radial direction of the base valve member 191 through which the hydraulic fluid can flow between the lower chamber 20 and the reservoir 6. The disc 192 on the reservoir 6 side allows the flow of the oil from the lower chamber 20 to the reservoir 6 through the passage hole 195, while restricting the flow of the oil from the reservoir 6 to the lower chamber 20 through the passage hole 195. The disc 193 allows the flow of the oil from the reservoir 6 to the lower chamber 20 through the passage hole 196, and restricts the flow of the oil from the lower chamber 20 to the reservoir 6 through the passage hole 196.

The disc 192 is configured as a compression-side damping valve mechanism 197 that opens during a compression stroke of the shock absorber 1 by the base valve member 191, flows the hydraulic fluid from the lower chamber 20 into the reservoir chamber 6, and generates a damping force. The disc 193 and the base valve member 191 constitute a suction valve mechanism 198 which opens during an extension stroke of the shock absorber 1 to allow the hydraulic fluid to flow from the reservoir 6 into the lower chamber 20. The intake valve mechanism 198 mainly functions as follows: the oil is caused to flow from the reservoir 6 to the lower chamber 20 without substantially generating a damping force to compensate for a shortage of the liquid generated by the extension of the piston rod 21 from the cylinder 2.

When the shock absorber 1 is assembled, as shown in fig. 4, the cap member 108, the disks 107, the disks 106 constituting the sub-valve 171, the valve seat member 105, and the seal member 103 are assembled in advance to form a sub-assembly 200.

In this case, for example, the disks 107 are fitted to the inner cylindrical portion 126 of the cap member 108 in a state where the bottom portion 122 is positioned at the lower portion in the vertical direction, the disks 107 are placed on the bottom portion 122 of the cap member 108, and the disks 106 are further fitted to the inner cylindrical portion 126, whereby the disks 106 are placed on the disks 107.

Then, the seat member 105 in a state in which the seal member 103 is attached to the seal groove 145 is oriented toward the disk 106 with the inner seat portion 134, the intermediate seat portion 135, and the outer seat portion 136, and the outer peripheral portion of the body portion 132 and the outer peripheral portion of the seal member 103 are inserted into the outer tube portion 124 of the cap member 108, and the inner tube portion 126 is fitted into the large diameter hole portion 130 while the seal member 103 and the body portion 132 are guided by the outer tube portion 124. Then, the valve seat member 105 and the bottom portion 122 of the cap member 108 are in a state of sandwiching the plurality of disks 106 and the plurality of disks 107.

Here, when the outer peripheral portion of the body 132 and the outer peripheral portion of the seal member 103 are inserted into the outer tube portion 124 of the cap member 108, the opening diameter-enlarged portion 125 of the cap member 108 is guided so as to be positioned in the radial direction. When the inner tube portion 126 is fitted into the large-diameter hole portion 130, the chamfer 127 on the outer peripheral side of the inner tube portion 126 is guided so as to position the valve seat member 105 in the radial direction.

When the seal member 103 is inserted into the outer tube portion 124 of the cap member 108 in a state of being attached to the valve seat member 105, it is compressed and deformed in the radial direction, and reaction forces are applied to both the valve seat member 105 and the outer tube portion 124, so that a frictional force is generated between both the valve seat member 105 and the outer tube portion 124. In this state, the relative axial movement of the valve seat member 105 and the cap member 108 is restricted only by the frictional force of the seal member 103. As a result, the large-diameter hole 130 and the inner tube portion 126 are maintained in the fitted state, and therefore, the plurality of disks 106 and 107 fitted to the inner tube portion 126 are restricted from being detached from the inner tube portion 126 by the valve seat member 105. Thus, the plurality of disks 106 and the plurality of disks 107 are maintained in a state of being fitted to the inner cylindrical portion 126, and are therefore maintained in a state of being positioned in the radial direction with respect to the cap member 108 and being restricted from being displaced in the radial direction.

In this way, the cap member 108, the disks 107, the disks 106, the valve seat member 105, and the seal member 103 form the sub-assembly 200. In other words, the valve seat member 105 can be assembled to the cap member 108 with the seal member 103 provided on the outer periphery.

As shown in fig. 2, when the piston 18 and the sub-assembly 200 are assembled to the piston rod 21, for example, the annular member 67, the disk 66, the disk 65, the disks 64, the disks 63, the disk 62, and the piston 18 are stacked in this order on the shaft step portion 29 while the attachment shaft portion 28 of the piston rod 21, which is positioned in the upper portion in the vertical direction, is inserted. At this time, the piston 18 has the small-diameter hole portion 45 oriented closer to the shaft step portion 29 than the large-diameter hole portion 46. In addition, while inserting the mounting shaft portion 28, the disk 82, the disks 83, the disks 84, the disks 101, and the disks 102 are stacked in this order on the piston 18.

Then, the sub-assembly 200 is superimposed on the disk 102 in the valve seat member 105 in a direction in which the opening diameter-increased portion 125 of the cap member 108 faces the piston 18 side while the mounting shaft portion 28 is inserted. At this time, the inner tube portion 126 of the cap member 108 is fitted to the mounting shaft portion 28.

Further, while fitting the mounting shaft portions 28, the disk 110 and the annular member 111 are sequentially stacked on the bottom portion 122 of the cap member 108. In this state, the nut 112 is screwed to the male screw 31 of the piston rod 21 protruding from the annular member 111, and the inner peripheral sides of the nut 112 and the shaft step 29 are clamped in the axial direction.

At this time, the inner tube portion 126 of the cap member 108 does not abut against the valve seat member 105 in the axial direction, and the fastening axial force from the nut 112 is transmitted to the shaft step portion 29 via the annular member 111, the disk 110, the bottom portion 122 of the cap member 108, the disks 107, the disks 106, the inner seat portion 134 of the valve seat member 105, the body portion 132, the inner seat portion 138, the disk 102, the disks 101, the disks 84, the disks 83, the disk 82, the inner seat portion 47 of the piston, the body portion 34, the inner seat portion 49, the disk 62, the disks 63, the disks 64, the disks 65, the disks 66, and the annular member 67. Thus, the inner tube portion 126 of the cap member 108 is kept away from the axial force transmission path, and the end portion of the inner tube portion 126 on the side opposite to the bottom portion 122 is configured not to be used for the axial force transmission.

In this state, the main valve 71 is clamped on the inner circumferential side by the inner seat portion 49 of the piston 18 and the disk 65 via the disk 62, and the outer circumferential side abuts on the valve seat portion 50 of the piston 18 over the entire circumference. In this state, the main valve 91 is clamped on the inner circumferential side by the inner seat portion 47 of the piston 18 and the disk 84 via the disk 82, and the outer circumferential side abuts on the valve seat portion 48 of the piston 18 over the entire circumference. In this state, the sub-valve 181 is clamped on the inner circumferential side by the inner seat portion 138 of the seat member 105 and the disk 84, and the outer circumferential side is in contact with the seat portion 139 of the seat member 105 over the entire circumference. In this state, the sub-valve 171 is clamped on the inner circumferential side by the inner seat portion 134 of the seat member 105 and the disk 107, and the outer circumferential side is in contact with the intermediate seat portion 135 and the outer seat portion 136 of the seat member 105 over the entire circumference.

Here, the main valve 91 of the first damping force generation mechanism 41 and the second damping force generation mechanism 183, both of which are on the extension side, has higher rigidity and higher valve opening pressure than the sub valve 181 of the second damping force generation mechanism 183. Thus, in the extension stroke, in the extremely low speed region where the piston speed is a low speed equal to or less than the predetermined value, the second damping force generating mechanism 183 is opened with the first damping force generating mechanism 41 closed. In the normal speed region where the piston speed is greater than the predetermined value, both the first damping force generating means 41 and the second damping force generating means 183 are opened. The sub valve 181 is a very low speed valve that opens in a region where the piston speed is very low to generate a damping force.

That is, in the extension stroke, the piston 18 moves toward the upper chamber 19, the pressure of the upper chamber 19 increases, and the pressure of the lower chamber 20 decreases, but since the orifice portion is not fixed to either of the first damping force generation mechanisms 41 and 42 and the second damping force generation mechanisms 173 and 183, the hydraulic fluid does not flow until the second damping force generation mechanism 183 opens. Therefore, the damping force rapidly increases in the extension stroke in which the piston speed is less than the first predetermined value. In a region where the piston speed is equal to or higher than the first predetermined value in which the second damping force generating mechanism 183 is opened, and in a very low speed region where the piston speed is lower than or equal to the second predetermined value which is higher than the first predetermined value, the second damping force generating mechanism 183 is opened with the first damping force generating mechanism 41 closed.

That is, the sub-valve 181 is separated from the seat portion 139, and the upper chamber 19 and the lower chamber 20 communicate with each other through the extension-side second passage 182. Thus, the hydraulic fluid in the upper chamber 19 flows into the lower chamber 20 through the passage in the passage hole 37 of the piston 18, the orifice 175, the passage in the large diameter hole 46 of the piston 18, the passage in the passage notch 30 of the piston rod 21, the passage in the small diameter hole 129 of the cap member 108, the orifice 176, the sub valve 181, and the passage between the seat portions 139. Thus, even in an extremely low speed region where the piston speed is equal to or lower than the second predetermined value, a damping force of the valve characteristic (a characteristic in which the damping force is substantially proportional to the piston speed) can be obtained.

In the extension stroke, in the normal speed region where the piston speed is greater than the second predetermined value, the first damping-force generating mechanism 41 is opened while the second damping-force generating mechanism 183 is still open.

That is, the sub valve 181 is separated from the seat portion 139, and the hydraulic fluid is caused to flow from the upper chamber 19 to the lower chamber 20 by the second passage 182 on the expansion side. At this time, the flow of the hydraulic fluid is throttled by the throttle portions 175 and 176 provided on the downstream side of the main valve 91 in the second passage 182, so that the pressure applied to the main valve 91 becomes high, the differential pressure increases, and the hydraulic fluid flows from the upper chamber 19 to the lower chamber 20 through the first passage 92 on the extension side with the main valve 91 separated from the valve seat portion 48. Thereby, the hydraulic fluid in the upper chamber 19 flows into the lower chamber 20 through the passage in the passage hole 37 and the passage between the main valve 91 and the seat portion 48. Thus, even in the normal speed region where the piston speed is greater than the second predetermined value, the damping force of the valve characteristic (the damping force is substantially proportional to the piston speed) can be obtained.

Here, in the extension stroke, in a normal speed region where the piston speed is greater than the second predetermined value, the differential pressure between the upper chamber 19 and the lower chamber 20 is greater than an extremely low speed region where the differential pressure is greater than the first predetermined value, but not greater than the second predetermined value, but since the first passage 92 is not throttled by the throttle portion, the hydraulic fluid can be made to flow at a large flow rate through the first passage 92 by opening the main valve 91. Further, the second passage 182 is throttled by the throttles 175, 176, so that deformation of the sub-valve 181 can be suppressed.

At this time, pressure in the opposite direction is applied from the lower chamber 20 and the cap chamber 146 to the sub valve 171 in the closed state. Even if the differential pressure between the upper chamber 19 and the lower chamber 20 increases, the second passage 182 has the throttles 175 and 176 formed on the upstream side of the sub-valve 171, so that the pressure rise in the cap chamber 146 becomes gentle with respect to the pressure rise in the upper chamber 19, and the pressure difference between the cap chamber 146 and the lower chamber 20 is suppressed from increasing. This can suppress an increase in the pressure difference between the cap chamber 146 and the lower chamber 20, which is received by the sub-valve 171 in the closed state, and can suppress application of a large back pressure from the cap chamber 146 side to the lower chamber 20 side to the sub-valve 171.

The shock absorber 1 is provided with a first passage 92 and a second passage 182, which are passages through which the hydraulic fluid flows from the upper chamber 19 to the lower chamber 20, in parallel during the extension stroke, and a main valve 91 and a sub valve 181 in parallel. The throttles 175 and 176 are connected in series to the sub valve 181.

As described above, in the extension stroke, in the normal speed region where the piston speed is greater than the second predetermined value, the main valve 91 is opened, and the hydraulic fluid can be made to flow at a large flow rate through the first passage 92. This reduces the flow rate through the second passage 182 between the sub-valve 181 and the seat portion 139. Therefore, the valve rigidity of the sub-valve 181 can be reduced. This can reduce the rate of increase in the damping force with respect to the increase in the piston speed in the region where the piston speed is normal speed, for example. In other words, the inclination of the increase rate of the damping force on the extension side with respect to the increase in the piston speed in the normal speed region can be made flat compared to the extremely low speed region. This can increase the degree of freedom in design.

The main valve 71 of the first damping force generation mechanism 42 and the second damping force generation mechanism 173, both on the compression side, has a higher rigidity and a higher valve opening pressure than the sub-valve 171 of the second damping force generation mechanism 173. Thus, in the compression stroke, in the extremely low speed region where the piston speed is low at or below the predetermined value, the second damping force generating means 173 is opened with the first damping force generating means 42 closed, and in the normal speed region where the piston speed is greater than the predetermined value, both the first damping force generating means 42 and the second damping force generating means 173 are opened. The sub valve 171 is an extremely low speed valve that opens in a region where the piston speed is extremely low to generate a damping force.

That is, in the compression stroke, the piston 18 moves toward the lower chamber 20 to increase the pressure of the lower chamber 20 and decrease the pressure of the upper chamber 19, but since the orifice is not fixed to either of the first damping force generation mechanisms 41 and 42 and the second damping force generation mechanisms 173 and 183, the hydraulic fluid does not flow until the second damping force generation mechanism 173 opens. Therefore, the damping force rises sharply.

In a region where the piston speed is equal to or higher than the third predetermined value in which the second damping force generating mechanism 173 is opened, and in a very low speed region where the piston speed is lower than the fourth predetermined value which is higher than the third predetermined value and is lower than the fourth predetermined value, the second damping force generating mechanism 173 is opened with the first damping force generating mechanism 42 closed.

That is, the sub-valve 171 is separated from the outer seat portion 136, and the lower chamber 20 and the upper chamber 19 communicate with each other through the compression-side second passage 172. Accordingly, the oil in the lower chamber 20 flows into the upper chamber 19 through the passage in the outer passage hole 143, the passage between the sub valve 171 and the outer seat portion 136, the cap chamber 146, the passage in the through hole 161 of the sub valve 171, the passage in the inner passage hole 141, the orifice portion 176, the passage in the small diameter hole portion 129 of the seat member 105, the passage in the passage notch portion 30 of the piston rod 21, the passage in the large diameter hole portion 46 of the piston 18, the orifice portion 175, and the passage in the passage hole 37 of the piston 18. Thus, even in an extremely low speed region where the piston speed is low and equal to or less than the fourth predetermined value, the damping force of the valve characteristic (characteristic in which the damping force is substantially proportional to the piston speed) can be obtained.

In the compression stroke, in the normal speed region where the piston speed is greater than the fourth predetermined value, the first damping force generating mechanism 42 is opened while the second damping force generating mechanism 173 is still open. That is, the sub-valve 171 is separated from the outer seat portion 136, and the hydraulic fluid is caused to flow from the lower chamber 20 to the upper chamber 19 by the compression-side second passage 172. At this time, since the second passage 172 throttles the flow rate of the hydraulic fluid by the throttles 176 and 175, the differential pressure generated in the main valve 71 increases, the main valve 71 separates from the seat portion 50, and the hydraulic fluid flows from the lower chamber 20 to the upper chamber 19 by the compression-side first passage 72. Thereby, the oil in the lower chamber 20 flows through the passage between the main valve 71 and the seat portion 50 and the passage in the passage hole 39. Thus, even in the normal speed region where the piston speed is greater than the fourth predetermined value, a damping force having a valve characteristic (the damping force is substantially proportional to the piston speed) can be obtained.

Here, the rate of increase of the damping force on the compression side with respect to the increase of the piston speed in the normal speed region is lower than the rate of increase of the damping force on the compression side with respect to the increase of the piston speed in the extremely low speed region. In other words, the inclination of the increase rate of the compression-side damping force with respect to the increase in the piston speed in the normal speed region can be leveled off in the extremely low speed region.

In the compression stroke, in a normal speed range in which the piston speed is greater than the fourth predetermined value, the differential pressure between the lower chamber 20 and the upper chamber 19 is greater than that in the extremely low speed range, but since the first passage 72 is not throttled by the throttle portion, the main valve 71 can be opened to allow the hydraulic fluid to flow through the first passage 72 at a large flow rate. This reduces the flow rate through the sub-valve 171, and therefore the valve rigidity of the sub-valve 171 can be reduced. This can reduce the damping force in the region where the piston speed is normal, and can increase the degree of freedom in design.

At this time (when the piston speed is high), the differential pressure between the lower chamber 20 and the upper chamber 19 increases, but the second passage 172 is throttled by the throttles 176 and 175, so that the pressure in the cap chamber 146 communicating with the upper chamber 19 via the throttles 176 and 175 becomes the pressure between the lower chamber 20 and the upper chamber 19, and therefore, the differential pressure of the lower chamber 20 can be suppressed from becoming excessively large.

Further, the main valve 71 can be opened to allow the hydraulic fluid to flow through the first passage 72 at a large flow rate, thereby suppressing deformation of the sub valve 171.

At this time, the pressure in the opposite direction is applied from the lower chamber 20 to the cap chamber 146 in the closed state of the sub valve 181, but the differential pressure between the lower chamber 20 and the upper chamber 19 is large, but the lower chamber 20 and the cap chamber 146 are opened and communicated by the sub valve 171, and the throttle portions 176 and 175 are provided between the cap chamber 146 and the upper chamber 19 on the downstream side of the sub valve 181, so that it is possible to suppress an excessive decrease in the pressure in the cap chamber 146, and to increase the pressure in the cap chamber 146 in accordance with an increase in the pressure in the lower chamber 20. Accordingly, a pressure difference between the upstream and downstream surfaces of the sub valve 181 is small, and a large back pressure from the lower chamber 20 side to the cap chamber 146 side can be suppressed from being applied to the sub valve 181.

In the shock absorber 1 described above, the first passage 72 and the second passage 172 are provided in parallel as a flow path through which the oil flows from the lower chamber 20 to the upper chamber 19 during the compression stroke, and the main valve 71 and the sub valve 171 are provided in parallel. The throttles 176 and 175 are connected in series to the sub valve 171 in the second passage 172.

In the compression stroke, the damping force characteristics of the damping valve mechanism 197 of the base valve 25 are also matched.

In the extension stroke, in the normal speed range in which the piston speed is greater than the second predetermined value, the differential pressure between the upper chamber 19 and the lower chamber 20 becomes greater than the extremely low speed range equal to or less than the second predetermined value, but since the pressure rise in the cap chamber 146 can be suppressed by the throttle portions 176 and 175 formed on the upstream side of the sub valve 171, the deformation caused by the back pressure of the sub valve 171 can be suppressed. In the compression stroke, in a normal speed range in which the piston speed is greater than the fourth predetermined value, the differential pressure between the lower chamber 20 and the upper chamber 19 is greater than an extremely low speed range in which the differential pressure is equal to or less than the fourth predetermined value, but the hydraulic fluid flows at a large flow rate through the first passage 72, and the restriction portions 176 and 175 restrict the flow rate of the hydraulic fluid in the second passage 172 downstream of the sub valve 171, whereby deformation of the sub valve 171 can be suppressed. This can improve the durability of the sub-valve 171.

In the extension stroke, in a normal speed region where the piston speed is greater than the second predetermined value, the differential pressure between the upper chamber 19 and the lower chamber 20 is greater than an extremely low speed region where the differential pressure is equal to or less than the second predetermined value, but the hydraulic fluid flows at a large flow rate through the first passage 92, and the second passage 182 is throttled by the throttles 175, 176, whereby deformation of the sub-valve 181 can be suppressed. In the compression stroke, in a normal speed range in which the piston speed is greater than the fourth predetermined value, the differential pressure between the lower chamber 20 and the upper chamber 19 increases, but the lower chamber 20 and the cap chamber 146 communicate with each other through the open valve of the sub valve 171, and the cap chamber 146 throttles the flow of the oil to the upper chamber 19 by the throttle portions 176 and 175 provided between the cap chamber and the upper chamber 19. Therefore, the differential pressure between the lower chamber 20 and the cap chamber 146 is small, and deformation due to the back pressure of the sub-valve 181 can be suppressed. This can improve the durability of the sub-valve 181.

Since the second damping force generating mechanisms 173 and 183 are provided independently in the compression stroke and the extension stroke, the degree of freedom in setting the damping force characteristics is increased.

Patent documents 1 to 3 describe that two valves are provided to open in the same stroke, but the number of parts increases. Thus, the productivity will be lowered.

The damper 1 of the first embodiment includes: a first damping force generating mechanism 41 provided in a first passage 92 formed on the extension side of the piston 18 and generating a damping force; and a second damping force generating mechanism 183 provided in the annular valve seat member 105 disposed in the lower chamber 20 and provided in the second passage 182 on the expansion side in parallel with the first passage 92, and generating a damping force. Further, the apparatus comprises: a first damping force generating mechanism 42 provided in a first passage 72 formed on the compression side of the piston 18 and generating a damping force; and a second damping force generating mechanism 173 provided in the annular valve seat member 105 disposed in the lower chamber 20 and provided in the second passage 172 on the compression side in parallel with the first passage 72 to generate a damping force. In this way, even in a configuration in which the number of components is large, the second damping force generating mechanisms 173 and 183 are configured to include the sub valve 181 provided on one side of the second passages 172 and 182 formed in the valve seat member 105, the sub valve 171 provided on the other side, and the bottomed cylindrical cap member 108 having the outer cylindrical portion 124 and the bottom portion 122, and the inner cylindrical portion 126 into which the piston rod 21 is inserted is formed on the inner circumferential side of the bottom portion 122 of the cap member 108, and the sub valve 171 which is a part of the second damping force generating mechanism 173 is housed. This allows the sub-valve 171 to be housed in the cap member 108 in advance, and the piston rod 21 to be inserted into the inner tube 126, thereby improving productivity. This can reduce the cost. Further, since automatic assembly is possible, the productivity can be further improved by setting to automatic assembly, and cost reduction and defective product occurrence rate reduction can be realized.

Further, since the sub valve 171 can be positioned, i.e., centered, in the radial direction with respect to the cap member 108 by the inner cylindrical portion 126 of the cap member 108, the sub valve 171 does not become misaligned even in the sub-assembled state. Thereby, automatic assembly becomes easier, and therefore, productivity can be further improved.

Further, since the sub-valve 171 and the valve seat member 105 are accommodated in the cap member 108, and the valve seat member 105 is sub-assembled to the cap member 108 by the seal member 103 provided on the outer periphery, the productivity of sub-assembly can be improved as compared with the case of performing press-fitting, caulking, or the like.

In addition, since the cap member 108 is formed by press forming, the productivity of the cap member 108 can be improved.

Patent document 3 describes that two oil chambers are connected by parallel flow paths, and valves that open in the same stroke are arranged in parallel by providing valves in the flow paths. By adopting the structure in which the valves that open in the same stroke are arranged in parallel in this manner, one valve can be opened in a region where the piston speed is lower than the other valve, and both valves can be opened in a region where the piston speed is higher than the piston speed. In such a configuration, it is particularly required to improve the durability of the valve on the low speed side.

In contrast, in the shock absorber 1 of the first embodiment, the sub-valves 171 and 181 of the second damping force generation mechanisms 173 and 183 of the second passages 172 and 182 that are parallel to the first passages 72 and 92 of the pistons 18 in which the first damping force generation mechanisms 41 and 42 are provided in the seat member 105 disposed in the lower chamber 20. Further, a cylindrical cap member 108 is disposed between the piston 18 and the valve seat member 105 in the second passages 172 and 182, and the valve seat member 105 is disposed inside the cap member 108. At this time, the sub valve 181 is provided on the lower chamber 20 side, and the sub valve 171 is provided in the cap chamber 146 between the bottom portion 122 of the cap member 108 and the valve seat member 105. The throttles 175 and 176 are disposed on the upstream side of the flow in the extension stroke of the second passage 182 in which the sub valve 181 is opened. Thus, in the compression stroke, the flow of the hydraulic fluid flowing from the lower chamber 20 into the cap chamber 146 by opening the sub valve 171 and flowing into the upper chamber 19 is throttled by the throttles 175, 176. Therefore, the differential pressure between the cap chamber 146 and the lower chamber 20 becomes small, and the sub-valve 181 in the closed state, which receives the back pressure from the lower chamber 20, receives the same pressure as the lower chamber 20 from the cap chamber 146, and can suppress the received back pressure (differential pressure). This can improve the durability of the sub-valve 181.

Further, since the piston rod 21 is inserted into the piston 18, the cap member 108, and the valve seat member 105, the piston 18, the cap member 108, and the valve seat member 105 can be arranged compactly.

Since the throttle portion 175 is formed by cutting the disc 82 abutting on the piston 18 in the extension-side first damping force generation mechanism 41, the throttle portion 175 can be easily formed.

Since the throttle portion 176 is formed by cutting the disc 102 abutting on the valve seat member 105 in the second damping force generation mechanism 183 on the expansion side, the throttle portion 176 can be easily formed.

Since a part of each of the second passages 172, 182 is formed by cutting the piston rod 21, the second passages 172, 182 can be easily formed.

Since the sub valve 171 as an inflow valve into the cap chamber 146 has a lower opening pressure than the sub valve 181, the sub valve 171 is easily opened from the lower chamber 20 during the compression stroke to allow the oil to flow into the cap chamber 146. Thus, in a state where the pressure of the lower chamber 20 is lower, the sub-valve 181 in the closed state receives the same pressure as the lower chamber 20 from the cap chamber 146, and suppresses the received back pressure. This can further improve the durability of the sub-valve 181.

Further, since the differential pressure between the cap chamber 146 and the lower chamber 20 does not increase in both the expansion and contraction strokes, a thin plate press-formed member can be used for the cap member 108, which is advantageous in terms of manufacturability and weight reduction.

Further, the two serial orifices of the orifice 175 and the orifice 176 improve the degree of freedom in setting the orifice.

In the first embodiment, the sub-assembly 200 and the sub-valve 181 may be attached in the axial direction in the opposite direction to the above direction. In this case, the bottom portion 122 of the cap member 108 of the sub-assembly 200 is brought into contact with the disk 84, the sub-valve 181 is disposed on the side of the sub-assembly 200 opposite to the disk 84, and a plurality of disks similar to the disk 84 are provided between the sub-valve 181 and the disk 110 in order to secure the deformation amount of the sub-valve 181. Then, the passage in the passage cut-out portion 30 of the piston rod 21 is communicated with the passage in the through hole 131.

[ second embodiment ]

Next, the second embodiment will be described centering on differences from the first embodiment, mainly with reference to fig. 5. The same portions as those in the first embodiment are denoted by the same names and the same reference numerals.

In the damper 1A according to the second embodiment, as shown in fig. 5, the axial lengths of the outer tube portion 124 and the inner tube portion 126 of the cap member 108 are longer than those of the first embodiment.

Further, a gasket 211 and a disk 212 are provided between the bottom 122 of the cap member 108 and the disk 107. The washer 211 and the disk 212 are made of metal, and both have a perforated disc shape into which the inner tube portion 126 of the cap 108 can be fitted. The gasket 211 and the disc 212 are fitted to the inner tube portion 126 and positioned radially with respect to the inner tube portion 126.

The disk 212 is a perforated circular flat plate having a constant thickness, and has an outer diameter larger than the outer diameter of the disk 107 and smaller than the outer diameter of the disk 106.

The gasket 211 has a chamfer 221 formed over the entire circumference at the inner peripheral edge portion on one axial side, and a chamfer 222 formed over the entire circumference at the outer peripheral edge portion on the same axial side. The chamfers 221 and 222 are formed so that a cross section of a surface including the central axis of the gasket 211 becomes linear. The chamfers 221 and 222 may be formed so that a cross section of a surface including the central axis of the washer 211 has an arc shape. The gasket 211 has a perforated circular flat plate shape with a certain thickness except for the chamfers 221 and 222. The side of the washer 211 where the axial chamfers 221, 222 are formed abuts the bottom 122 of the cap member 108, and the side where the axial chamfers 221, 222 are not formed abuts the disk 212. The washer 211 has an outer diameter larger than the outer diameter of the disc 212 and smaller than the outer diameter of the disc 106.

In the second embodiment, a plurality of disks 106, a plurality of disks 107, a valve seat member 105, and a seal member 103, which are similar to those of the first embodiment, are housed in a cap member 108, and a gasket 211 and a disk 212 are housed in the cap member 108. The axial length of cap member 108 is longer than the first embodiment by the thickness of the washer 211 and disk 212.

By providing the washer 211 and the disk 212 between the bottom 122 of the cap member 108 and the disk 107 in accordance with the axial length of the cap member 108 thus increased, the axial length of the attachment shaft portion 28 of the piston rod 21 is also longer than that of the first embodiment.

When assembling the shock absorber 1A according to the second embodiment, the cap member 108, the gasket 211, the disk 212, the disks 107, the disks 106 constituting the sub-valve 171, the valve seat member 105, and the seal member 103 are assembled in advance to form the sub-assembly 200A.

In this case, for example, the gasket 211 is fitted to the inner tube portion 126 of the cap member 108 in a state where the bottom portion 122 is positioned at the lower portion in the vertical direction, and the disk 212 is placed on the gasket 211 by fitting the gasket 211 to the inner tube portion 126 in addition to the fact that the gasket 211 is brought into contact with the bottom portion 122 of the cap member 108 on the chamfered sides 221 and 222 in the axial direction. The disks 107 are placed on the disks 212 by fitting the disks 107 into the inner cylindrical portion 126, and the disks 106 are placed on the disks 107 by fitting the disks 106 into the inner cylindrical portion 126.

Then, the valve seat member 105 in a state in which the seal member 103 is attached to the seal groove 145 is oriented toward the disk 106 with the inner seat portion 134, the intermediate seat portion 135, and the outer seat portion 136, and the outer peripheral portion of the body portion 132 and the outer peripheral portion of the seal member 103 are fitted to the outer tube portion 124 of the cap member 108, and the large-diameter hole portion 130 is fitted to the inner tube portion 126 while the body portion 132 is guided by the outer tube portion 124. Then, the valve seat member 105 and the bottom portion 122 of the cap member 108 are in a state of sandwiching the plurality of disks 106, the plurality of disks 107, the disks 212, and the gasket 211. In other words, the gasket 211 is provided between the bottom 122 and the sub-valve 171 formed by the disk 106 in the cap member 108.

When the seal member 103 is inserted into the outer tube portion 124 of the cap member 108 in a state of being attached to the valve seat member 105, a frictional force is generated between both the valve seat member 105 and the outer tube portion 124, and the relative axial movement of the valve seat member 105 and the cap member 108 is regulated, as in the first embodiment. As a result, the large-diameter hole 130 and the inner tube portion 126 are maintained in the fitted state, and therefore, the plurality of disks 106, 107, 212, and the gasket 211 fitted to the inner tube portion 126 are restricted from being detached from the inner tube portion 126 by the valve seat member 105. Thus, the disks 106, 107, 212, and the washer 211 are maintained in a state of being fitted to the inner tube portion 126, and are therefore maintained in a state of being positioned in the radial direction with respect to the cap member 108 and being restricted from being displaced in the radial direction. In this way, the cap member 108, the gasket 211, the disk 212, the disks 107, the disks 106, the valve seat member 105, and the seal member 103 form the sub-assembly 200A as a single body.

When the piston 18 and the sub-assembly 200A are assembled to the piston rod 21, for example, as in the first embodiment, the annular member 67, the disk 66, the disk 65, the disks 64, the disks 63, the disk 62, the piston 18, the disk 82, the disks 83, the disks 84, the disks 101, and the disks 102 are sequentially stacked on the shaft step portion 29 while fitting the attachment shaft portion 28 of the piston rod 21 with the attachment shaft portion 28 positioned in the upper portion in the vertical direction.

Then, the sub-assembly 200A is set such that the opening diameter-increasing portion 125 of the cap member 108 faces the piston 18 side while the mounting shaft portion 28 is fitted, and is superimposed on the disk 102 at the valve seat member 105. At this time, the inner tube portion 126 of the cap member 108 is fitted to the mounting shaft portion 28.

Further, while fitting the mounting shaft portions 28, the disk 110 and the annular member 111 are sequentially stacked on the bottom portion 122 of the cap member 108. In this state, the nut 112 is screwed to the male screw 31 of the piston rod 21 protruding from the annular member 111, and the inner peripheral sides of the nut 112 and the shaft step 29 are clamped in the axial direction.

At this time, the inner tube portion 126 of the cap member 108 does not come into contact with the valve seat member 105 in the axial direction, and the fastening axial force from the nut 112 is transmitted to the spindle step portion 29 via the annular member 111, the disk 110, the bottom portion 122 of the cap member 108, the washer 211, the disk 212, the disks 107, the disks 106, the inner seat portion 134 of the valve seat member 105, the body portion 132, the inner seat portion 138, the disk 102, the disks 101, the disks 84, the disks 83, the disk 82, the inner seat portion 47 of the piston, the body portion 34, the inner seat portion 49, the disk 62, the disks 63, the disks 64, the disks 65, the disks 66, and the annular member 67.

In the damper 1A according to the second embodiment, since the gasket 211 having the chamfer 221 formed on the inner peripheral side is in contact with the bottom portion 122 of the cap member 108 on the chamfer 221 side, even if the bending accuracy of the boundary portion between the bottom portion 122 and the inner tube portion 126 is low, the portion can be avoided by the chamfer 221. Thus, even if the bending accuracy of the boundary portion between the bottom portion 122 of the cap member 108 and the inner tube portion 126 is low, the member placed on the bottom portion 122 can be prevented from floating in the axial direction. This enables sufficient and stable generation of the fastening axial force by the nut 112. This can suppress the damping forces of the first damping-force generating mechanisms 41 and 42 and the second damping-force generating mechanisms 173 and 183 from becoming unstable. In other words, the machining accuracy of the cap member 108 can be relaxed, and the productivity of the cap member 108 can be improved.

In the second embodiment, as described in the first embodiment, the sub-assembly 200A and the sub-valve 181 can be mounted in the axial direction in the opposite direction to the above while securing the amount of deformation of the sub-valve 181 by the same disk as the disk 84.

[ third embodiment ]

Next, a third embodiment will be described centering on differences from the first embodiment, mainly with reference to fig. 6. The same portions as those in the first embodiment are denoted by the same names and the same reference numerals.

As shown in fig. 6, a shock absorber 1B according to a third embodiment is provided with a valve seat member 105B, a part of which is different from that of the valve seat member 105 according to the first embodiment. The seal groove 145 of the first embodiment is not formed in the valve seat member 105B, and the body portion 132B having an outer diameter larger than that of the body portion 132 of the first embodiment is provided. The outer diameter of the body 132B is an outer diameter that is press-fitted into the outer tube portion 124 of the cap member 108 with interference. A chamfer 225 is formed over the entire periphery of the outer peripheral edge portion on the outer seat portion 136 side in the axial direction of the seat member 105B.

The cap member 108 accommodates a plurality of disks 106, a plurality of disks 107, and a valve seat member 105B. Cap member 108 and valve seat member 105B constitute a housing 147B.

When the shock absorber 1B of the third embodiment is assembled, the cap member 108, the disks 107, the disks 106 constituting the sub-valve 171, and the valve seat member 105B are assembled in advance to form the sub-assembly 200B.

In this case, for example, the disks 107 are fitted to the inner cylindrical portion 126 of the cap member 108 in a state where the bottom portion 122 is positioned at the lower portion in the vertical direction, the disks 107 are placed on the bottom portion 122 of the cap member 108, and the disks 106 are fitted to the inner cylindrical portion 126, so that the disks 106 are placed on the disks 107.

Then, the seat member 105B is oriented in a direction in which the inner seat portion 134, the intermediate seat portion 135, and the outer seat portion 136 face the disk 106, and the outer peripheral portion of the main body portion 132B is press-fitted into the outer tube portion 124 of the cap member 108, so that the large-diameter hole portion 130 is fitted into the inner tube portion 126 while the main body portion 132B is guided by the outer tube portion 124. Then, the valve seat member 105B sandwiches the plurality of disks 106 and the plurality of disks 107 with the bottom portion 122 of the cap member 108.

When the outer peripheral portion of the body portion 132B is fitted to the outer tube portion 124 of the cap member 108 by press fitting, the opening diameter-enlarged portion 125 of the cap member 108 and the chamfer 225 of the body portion 132B are guided to be positioned in the radial direction. The valve seat member 105B is press-fitted into the outer tube portion 124, thereby sealing the space between the valve seat member and the outer tube portion 124. In this state, the sub-valve 171 formed of the disk 106 and the valve seat member 105B are accommodated in the cap member 108.

The valve seat member 105B is press-fitted into the outer tube portion 124 in this manner, and the valve seat member 105B and the cap member 108 are fixed while being restricted from relative axial movement and relative radial movement. At this time, since the large-diameter hole portion 130 and the inner tube portion 126 are maintained in the fitted state, the plurality of disks 106 and 107 fitted to the inner tube portion 126 are restricted from being detached from the inner tube portion 126 by the valve seat member 105B. Thus, the plurality of disks 106 and the plurality of disks 107 are maintained in a state of being fitted to the inner cylindrical portion 126, and are therefore maintained in a state of being positioned in the radial direction with respect to the cap member 108 and being restricted from being displaced in the radial direction. In this way, the cap member 108, the disks 107, the disks 106, and the valve seat member 105B form the sub-assembly 200B.

When the piston 18 and the sub-assembly 200B are assembled to the piston rod 21, for example, as in the first embodiment, the annular member 67, the disk 66, the disk 65, the disks 64, the disks 63, the disk 62, the piston 18, the disk 82, the disks 83, the disks 84, the disks 101, and the disks 102 are sequentially stacked on the shaft step portion 29 while fitting the attachment shaft portion 28 of the piston rod 21, which is in a state where the attachment shaft portion 28 is positioned at the upper portion in the vertical direction.

Then, the sub-assembly 200B is placed on the disk 102 in the valve seat member 105B in a direction in which the opening diameter-increased portion 125 of the cap member 108 faces the piston 18 side while the mounting shaft portion 28 is fitted. At this time, the inner tube portion 126 of the cap member 108 is fitted to the mounting shaft portion 28.

Further, while fitting the mounting shaft portions 28 to each other, the disk 110 and the annular member 111 are sequentially stacked on the bottom portion 122 of the cap member 108. In this state, the nut 112 is screwed to the male screw 31 of the piston rod 21 protruding from the annular member 111, and the inner peripheral sides of the nut 112 and the shaft step 29 are clamped in the axial direction.

In the shock absorber 1B of the third embodiment, the valve seat member 105B is press-fitted to the cap member 108 on the outer periphery, and therefore, a seal member therebetween can be eliminated. This can reduce the number of components. Further, since the valve seat member 105B is press-fitted into the cap member 108 to form the sub-assembly 200B, the auxiliary assembly state of the sub-assembly 200B can be stably maintained.

In the third embodiment, the same gasket 211 and disk 212 as those of the second embodiment may be provided between the bottom portion 122 of the cap member 108 and the disk 107.

In the third embodiment, as described in the first embodiment, the sub-assembly 200B and the sub-valve 181 can be mounted in the axial direction in the opposite direction to the above direction while ensuring the amount of deformation of the sub-valve 181 by the same disk as the disk 84.

[ fourth embodiment ]

Next, a fourth embodiment will be described centering on differences from the first embodiment, mainly with reference to fig. 7. The same portions as those in the first embodiment are denoted by the same names and the same reference numerals.

As shown in fig. 7, a shock absorber 1C according to a fourth embodiment is provided with a valve seat member 105C, a part of which is different from that of the valve seat member 105 according to the first embodiment. The seal groove 145 of the first embodiment is not formed in the valve seat member 105C, and the body portion 132C having an outer diameter larger than that of the body portion 132 of the first embodiment is provided. The outer diameter of the valve seat member 105C is an outer diameter that fits into the outer tube portion 124 of the cap member 108 with almost no gap. A chamfer 230 is formed over the entire circumference of the outer peripheral edge portion of the seat member 105C on the outer seat portion 136 side in the axial direction.

Further, in the damper 1C according to the fourth embodiment, a cap member 108C, which is partially different from the cap member 108 of the first embodiment, is provided instead. The cap member 108C has an annular locking portion 231 formed to extend radially inward from the side opposite to the bottom portion 122 in the axial direction of the outer tube portion 124, instead of the opening expanding portion 125 of the first embodiment.

The cap member 108C accommodates a plurality of disks 106, a plurality of disks 107, and a valve seat member 105C. Cap member 108C and valve seat member 105C constitute a housing 147C.

When the shock absorber 1C of the fourth embodiment is assembled, the cap member 108C, the disks 107, the disks 106 constituting the sub-valve 171, and the valve seat member 105C are assembled in advance to form the sub-assembly 200C.

In this case, for example, before the engagement portion 231 is formed, a cap member 108C having a shape in which the outer cylinder portion 124 extends to an end opposite to the bottom portion 122 is prepared, the cap member 108C is placed in a state in which the bottom portion 122 is positioned at a lower portion in the vertical direction, the disks 107 are fitted to the inner cylinder portion 126, the disks 107 are placed on the bottom portion 122 of the cap member 108C, and the disks 106 are fitted to the inner cylinder portion 126, and the disks 106 are placed on the disks 107.

Then, the seat member 105C is oriented in a direction in which the inner seat portion 134, the intermediate seat portion 135, and the outer seat portion 136 face the disk 106 side, the outer peripheral portion of the main body portion 132C is fitted to the outer tube portion 124 of the cap member 108C, and the large-diameter hole portion 130 is fitted to the inner tube portion 126 while the main body portion 132C is guided by the outer tube portion 124. Thereafter, the end portion of the outer tube portion 124 opposite to the bottom portion 122 is plastically deformed radially inward over the entire circumference by caulking, thereby forming the engagement portion 231. Then, the locking portion 231 sandwiches the valve seat member 105C, the plurality of disks 106, and the plurality of disks 107 with the bottom portion 122.

When the outer peripheral portion of the main body 132C is fitted to the outer tube portion 124 of the cap member 108 before caulking, the main body 132C is guided by the chamfer 230 of the main body 132C so as to be positioned in the radial direction. The locking portion 231 is formed by caulking, and the entire periphery of the seat member 105C and the locking portion 231 is sealed. In this state, the sub-valve 171 and the valve seat member 105C are housed in the cap member 108C.

The valve seat member 105C is fitted into the outer tube portion 124 and locked in the locking portion 231 in this manner, so that the valve seat member 105C and the cap member 108C are fixed while being restricted from relative axial movement and relative radial movement. At this time, since the large-diameter hole portion 130 and the inner tube portion 126 are maintained in the fitted state, the plurality of disks 106 and 107 fitted to the inner tube portion 126 are restricted from being detached from the inner tube portion 126 by the valve seat member 105C. Thus, the plurality of disks 106 and the plurality of disks 107 are maintained in a state of being fitted to the inner cylindrical portion 126, and are therefore maintained in a state of being positioned in the radial direction with respect to the cap member 108C and being restricted from being displaced in the radial direction. In this way, the cap member 108C, the disks 107, the disks 106, and the valve seat member 105C form the sub-assembly 200C.

When the piston 18 and the sub-assembly 200C are assembled to the piston rod 21, for example, as in the first embodiment, the annular member 67, the disk 66, the disk 65, the disks 64, the disks 63, the disk 62, the piston 18, the disk 82, the disks 83, the disks 84, the disks 101, and the disks 102 are sequentially stacked on the shaft step portion 29 while fitting the attachment shaft portion 28 of the piston rod 21, which is in a state where the attachment shaft portion 28 is positioned at the upper portion in the vertical direction.

Then, the sub-assembly 200C is caused to be overlapped on the disk 102 in the valve seat member 105C in a direction in which the locking portion 231 of the cap member 108C faces the piston 18 side while the mounting shaft portion 28 is fitted. At this time, the inner tube portion 126 of the cap member 108 is fitted to the mounting shaft portion 28.

Further, while fitting the mounting shaft portions 28 to each other, the disk 110 and the annular member 111 are sequentially stacked on the bottom portion 122 of the cap member 108C. In this state, the nut 112 is screwed to the male screw 31 of the piston rod 21 protruding from the annular member 111, and the inner peripheral sides of the nut 112 and the shaft step portion 29 are clamped in the axial direction.

In the shock absorber 1C of the fourth embodiment, the cap member 108C engages with the seat member 105C by caulking, and therefore, the seal member therebetween can be eliminated. This can reduce the number of components. Further, since the cap member 108C locks the valve seat member 105C by caulking, the auxiliary assembly state of the sub-assembly 200C can be stably maintained.

In the fourth embodiment, a structure may be adopted in which the same gasket 211 and disk 212 as in the second embodiment are provided between the bottom portion 122 of the cap member 108C and the disk 107.

In the fourth embodiment, as described in the first embodiment, the sub-assembly 200C and the sub-valve 181 can be mounted in the axial direction in the opposite direction to the above direction while ensuring the amount of deformation of the sub-valve 181 by the same disk as the disk 84.

[ fifth embodiment ]

Next, a fifth embodiment will be described centering on differences from the first embodiment, mainly with reference to fig. 8. The same portions as those in the first embodiment are denoted by the same names and the same reference numerals.

As shown in fig. 8, a shock absorber 1D according to a fifth embodiment is provided with a cap member 108D, which is partially different from the cap member 108 of the first embodiment. The cap member 108D is composed of two members, a first cap member 241 and a second cap member 242.

The first cap member 241 has the bottom 122, the outer tube portion 124, and the opening diameter-enlarged portion 125, which are similar to those of the first embodiment, but has a shape in which the inner tube portion 126 of the first embodiment is not formed. The first cap member 241 is fitted to the mounting shaft portion 28 at the bottom portion 122, and is positioned in the radial direction with respect to the mounting shaft portion 28.

The second cap member 242 has the inner tube portion 126 similar to the first embodiment, and a flange portion 245 extending radially outward from an end portion on the opposite side of the chamfers 127, 128 in the axial direction of the inner tube portion 126. In other words, the second cap member 242 is formed with the inner tube portion 126. The second cap member 242 is fitted to the mounting shaft portion 28 in the inner tube portion 126 and is positioned in the radial direction with respect to the mounting shaft portion 28.

The cap member 108D accommodates a plurality of disks 106, 107, a valve seat member 105, and a seal member 103. The cap member 108D, the valve seat member 105, and the seal member 103 constitute a housing 147D. The disks 106 and 107 are fitted into the inner tube portion 126 of the second cap member 242 and placed on the flange portion 245.

In the fifth embodiment, the number of disks 107 corresponds to the thickness of the flange portion 245 of the second cap member 242 and is one sheet smaller than that of the first embodiment. Further, the axial length of the cap member 108D and the axial length of the mounting shaft portion 28 are longer than those of the first embodiment in accordance with the number of unusable disks 107.

When the shock absorber 1D according to the fifth embodiment is assembled, the cap member 108D, the disk 107, the disks 106, the valve seat member 105, and the seal member 103, which are formed of two members, i.e., the first cap member 241 and the second cap member 242, are assembled in advance to form the sub-assembly 200D.

In this case, for example, the disk 107 is mounted on the flange portion 245 by fitting the disk 107 to the inner cylindrical portion 126 of the second cap member 242 in a state where the flange portion 245 is positioned at the lower portion in the vertical direction, and the disks 106 are mounted on the disk 107 by fitting the plurality of disks 106 to the inner cylindrical portion 126.

Then, the seat member 105 in a state in which the seal member 103 is attached to the seal groove 145 is placed on the disk 106 with the large-diameter hole portion 130 fitted to the inner tube portion 126 in a direction in which the inner seat portion 134, the intermediate seat portion 135, and the outer seat portion 136 face the disk 106 side. Then, the vertical direction of these is reversed, and the first cap member 241 is covered so that the outer tube portion 124 fits into the outer peripheral portion of the body portion 132 of the valve seat member 105 and the outer peripheral portion of the seal member 103. Then, the valve seat member 105 sandwiches the plurality of disks 106, the disk 107, and the flange portion 245 of the second cap member 242 with the bottom portion 122 of the first cap member 241.

When the outer tube portion 124 of the first cap member 241 is covered with the seal member 103 attached to the valve seat member 105, a frictional force is generated between the valve seat member 105 and the outer tube portion 124, as in the first embodiment. In this state, the relative axial movement of the valve seat member 105 and the first cap member 241 is restricted only by the frictional force of the seal member 103. Thus, relative axial movement of the valve seat member 105 and the second cap member 242 is also restricted. As a result, the large-diameter hole 130 and the inner tube 126 are maintained in a fitted state. Therefore, the disk seat member 105 restricts the disks 106 and 107 fitted to the inner tube portion 126 from being detached from the inner tube portion 126. Thus, the disks 106 and 107 are maintained in a state of being fitted to the inner cylindrical portion 126, and are therefore maintained in a state of being positioned in the radial direction with respect to the cap member 108 and being restricted from being displaced in the radial direction.

The valve seat member 105 fitted to the outer tube portion 124 via the seal member 103 is positioned in the radial direction with respect to the first cap member 241, and the large diameter hole portion 130 is fitted to the inner tube portion 126 so that the second cap member 242 is positioned in the radial direction with respect to the valve seat member 105. As a result, the second cap member 242 is positioned in the radial direction with respect to the first cap member 241. The disks 106 and 107 fitted into the inner cylindrical portion 126 of the second cap member 242 are positioned in the radial direction with respect to the cap member 108D, and are restricted from being displaced in the radial direction. In this way, the first cap member 241, the second cap member 242, the disk 107, the disks 106, the valve seat member 105, and the seal member 103 form the sub-assembly 200D.

When the piston 18 and the sub-assembly 200D are assembled to the piston rod 21, for example, as in the first embodiment, the annular member 67, the disk 66, the disk 65, the disks 64, the disks 63, the disk 62, the piston 18, the disk 82, the disks 83, the disks 84, the disks 101, and the disks 102 are sequentially stacked on the shaft step portion 29 while fitting the attachment shaft portion 28 of the piston rod 21, which is in a state where the attachment shaft portion 28 is positioned at the upper portion in the vertical direction.

Then, the sub-assembly 200D is fitted to the mounting shaft 28 and the disk 102 is superimposed on the valve seat member 105 such that the opening diameter-increased portion 125 of the cap member 108D faces the piston 18 side. At this time, the mounting shaft portion 28 is fitted into the inner tube portion 126 of the second cap member 242 and the bottom portion 122 of the first cap member 241.

Further, while fitting the mounting shaft portions 28 to each other, the disk 110 and the annular member 111 are sequentially stacked on the bottom portion 122 of the first cap member 241. In this state, the nut 112 is screwed to the male screw 31 of the piston rod 21 protruding from the annular member 111, and the inner peripheral sides of the nut 112 and the shaft step 29 are clamped in the axial direction.

At this time, the inner tube portion 126 of the second cap member 242 does not abut against the valve seat member 105 in the axial direction, and the fastening axial force from the nut 112 is transmitted to the shaft step portion 29 via the annular member 111, the disk 110, the bottom portion 122 of the first cap member 241, the flange portion 245 of the second cap member 242, the disk 107, the disks 106, the inner seat portion 134 of the valve seat member 105, the body portion 132, the inner seat portion 138, the disk 102, the disks 101, the disks 84, the disks 83, the disk 82, the inner seat portion 47 of the piston, the body portion 34, the inner seat portion 49, the disk 62, the disks 63, the disks 64, the disks 65, the disks 66, and the annular member 67.

The cap member 108D of the shock absorber 1D according to the fifth embodiment is composed of two members, i.e., a first cap member 241 having the bottom portion 122 and the outer tube portion 124, and a second cap member 242 forming the inner tube portion 126. Therefore, the forming by pressing becomes easy, and the generation rate of defective products can be reduced. In particular, when the cap member 108D has a long axial length, the forming by pressing is facilitated by providing two members.

In the fifth embodiment, the same gasket 211 and disk 212 as those of the second embodiment may be provided between the flange portion 245 of the second cap member 242 and the disk 107.

In the fifth embodiment, the valve seat member 105 may be press-fitted into the outer tube portion 124 of the first cap member 241 to eliminate the seal member 103, as in the third embodiment. In this case, the same structure as that of the second embodiment can be adopted in which the washer 211 and the disk 212 are provided.

Further, in the fifth embodiment, the following configuration may also be adopted: as in the fourth embodiment, a locking portion is formed by caulking the outer tube portion 124 of the first cap member 241 on the side opposite to the bottom portion 120, and the valve seat member 105 is locked by the locking portion, thereby eliminating the seal member 103. In this case, the same structure as that of the second embodiment can be adopted in which the washer 211 and the disk 212 are provided.

In the fifth embodiment, as described in the first embodiment, the sub-assembly 200D and the sub-valve 181 can be mounted in the axial direction in the opposite direction to the above while securing the amount of deformation of the sub-valve 181 by the same disk as the disk 84.

[ sixth embodiment ]

Next, the sixth embodiment will be described centering on differences from the first embodiment, mainly with reference to fig. 9. Parts corresponding to those in the first embodiment are denoted by the same names and the same reference numerals. The damper 1E of the sixth embodiment is a stopper-type damping force adjusting damper, and its basic structure and operation are the same as those of the damper described in japanese patent laid-open publication No. 2013-204772.

As shown in fig. 9, a buffer 1E according to a sixth embodiment includes: a cylinder 2 in which oil as a working fluid is sealed; a piston 18 slidably provided in the cylinder 2 and dividing the interior of the cylinder 2 into two chambers, an upper chamber 19 and a lower chamber 20; and a piston rod 21 coupled to the piston 18 and extending and protruding to the outside of the cylinder 2.

The piston rod 21 includes a main shaft portion constituting member 301 extending and protruding to the outside of the cylinder 2, and an attachment shaft portion constituting member 302 (guide member) disposed in the cylinder 2, and is configured by being connected to each other. The piston rod 21 has a mounting shaft portion 28 and a shaft step portion 29 formed in a mounting shaft portion constituting member 302.

The piston 18 is provided with a compression-side first passage 72 through which the oil supply liquid flows out from the lower chamber 20 on the upstream side to the upper chamber 19 on the downstream side in the cylinder 2 by the movement of the piston 18 to the compression side. The first damping force generating mechanism 41 including the compression-side main valve 71 that generates a damping force by providing the first passage 72 on the compression side is provided on the upper chamber 19 side of the piston 18.

Further, the piston 18 is provided with an extension-side first passage 92 through which the oil supply liquid flows out from the upper chamber 19, which is the upstream side, to the lower chamber 20, which is the downstream side, in the cylinder 2 by the movement of the piston 18 to the extension side. The lower chamber 20 side of the piston 18 is provided with a first damping force generation mechanism 42 on the extension side including a main valve 91 that generates a damping force by including a first passage 92 provided on the extension side.

The mounting shaft portion constituting member 302 provided in the piston rod 21 is cylindrical as a whole, and thus the mounting shaft portion 28 is also cylindrical. The cylindrical side wall 310 constituting the middle portion in the axial direction of the mounting shaft portion 28 has a guide port 311 penetrating in the radial direction, and a guide port 312 penetrating in the radial direction on the opposite side of the guide port 311 from the shaft step portion 29.

A cylindrical stopper member 321 is rotatably fitted into the mounting shaft portion component 302. The stopper member 321 is coupled to a rotary shaft 323 of an electric drive unit 322 (drive unit) provided in the main shaft component 301, and is thereby driven by the electric drive unit 322 to rotate in the mounting shaft component 302.

The stopper member 321 has a stopper port 342 facing the inlet port 311 and a stopper port 343 facing the inlet port 312 in a cylindrical side wall 341. The guide port 311 and the stopper port 342 opposed thereto can communicate with each other, and the amount of communication changes depending on the rotational position of the stopper member 321. The guide port 312 and the stopper port 343 opposed thereto can communicate with each other, and the amount of communication changes depending on the rotational position of the stopper member 321. The stopper ports 342, 343 are always communicated with the lower chamber 20 via the inner peripheral side of the stopper member 321 and the inner peripheral side of the mounting shaft portion constituting member 302.

Between the piston 18 and the shaft step 29 in the mounting shaft portion constituting member 302, an annular valve seat member 105 disposed in the upper chamber 19 of one of the upper chamber 19 and the lower chamber 20, a seal member 103 provided on the outer periphery of the valve seat member 105, and a cap member 108 having a bottomed cylindrical shape are provided.

The cap member 108 has: a bottom 122 having a perforated circular flat plate shape; a tapered cylindrical portion 123 which expands in diameter from the outer peripheral edge of the bottom portion 122 toward one axial side and which extends and protrudes; a cylindrical outer tube portion 124 extending and protruding from an end portion of the tapered tube portion 123 on the side opposite to the bottom portion 122 in the direction opposite to the bottom portion 122; an opening diameter-increasing portion 125 that extends and protrudes from an end portion of the outer tube portion 124 on the side opposite to the tapered tube portion 123 in a direction opposite to the tapered tube portion 123; and a cylindrical inner tube portion 126 extending from the inner peripheral edge portion of the bottom portion 122 to the same side as the tapered tube portion 123 and the outer tube portion 124.

The cap member 108 forms a cap chamber 146 by fitting the valve seat member 105 and the seal member 103 to the inside of the outer tube portion 124. A through hole 351 penetrating in the radial direction is formed in the inner tube portion 126 of the cap member 108. A through hole 352 penetrating in the radial direction is formed on the bottom portion 122 side of the through hole 351. The through hole 351 communicates with the guide port 311, and the through hole 352 communicates with the guide port 312.

The seat member 105 is formed with a passage hole 361 constituting the compression-side second passage 172 and a passage hole 362 constituting the expansion-side second passage 182. The valve seat member 105 has a through hole 374 formed at the radial center thereof, the through hole having a small diameter hole 371, an intermediate diameter hole 372, and a large diameter hole 373. In the valve seat member 105, the mounting shaft portion 28 is fitted in the small diameter hole portion 371, and the inner tube portion 126 of the cap member 108 is fitted in the intermediate diameter hole portion 372.

A second damping force generation mechanism 173 including a compression-side sub valve 171 that generates a damping force by providing a compression-side second passage 172 is provided on the shaft step portion 29 side of the valve seat member 105.

A second damping force generating mechanism 183 including an extension-side sub valve 181 that generates a damping force by including a second passage 182 provided on an extension side is provided on the opposite side of the valve seat member 105 from the shaft step portion 29. A passage forming member 381 which forms a passage penetrating in the radial direction is provided between the sub valve 181 and the piston 18. A passage forming member 382 that forms a passage penetrating in the radial direction is provided on the side of the sub valve 181 opposite to the piston 18.

The compression-side second passage 172 includes the passage on the inner peripheral side of the mounting shaft portion constituting member 302 and the stopper member 321, the passage in the stopper port 343 of the stopper member 321, the passage in the guide port 312 of the mounting shaft portion constituting member 302, the passage in the through hole 352 of the cap member 108, the passage in the passage forming member 382, the cap chamber 146, and the passage in the passage hole 361. The second passage 172 on the compression side causes the hydraulic fluid to flow out from the lower chamber 20 on the upstream side to the upper chamber 19 on the downstream side in the cylinder 2 by the movement of the piston 18 to the compression side. The compression-side second passage 172 is provided in parallel with the compression-side first passage 72. The second damping force generating mechanism 173 is provided in the second passage 172 to generate a damping force.

The second passage 182 on the expansion side has a passage in the passage hole 362, a passage in the passage forming member 381, a passage in the large diameter hole portion 373 of the valve seat member 105, a passage in the through hole 351 of the cap member 108, a passage in the guide port 311 of the mounting shaft portion constituting member 302, a passage in the stopper port 342 of the stopper member 321, a passage in the stopper member 321, and a passage on the inner peripheral side of the mounting shaft portion constituting member 302. The second passage 182 on the extension side includes a passage of the second damping force generating mechanism 183 in an open state, a passage in the cap chamber 146, the passage forming member 382, a passage in the through hole 352 of the cap member 108, a passage in the guide port 312 of the attachment shaft portion constituting member 302, and a passage in the stopper port 343 of the stopper member 321. The second passage 182 on the expansion side causes the oil to flow out from the upper chamber 19 on the upstream side to the lower chamber 20 on the downstream side in the cylinder 2 by the movement of the piston 18 to the expansion side. The extension-side second passage 182 is provided in parallel with the extension-side first passage 92. The second damping force generating mechanism 183 is provided in the second passage 182 to generate a damping force.

The mounting shaft portion constituting member 302, the stopper member 321, and the electric drive portion 322 constitute a part of the second damping force generating mechanisms 173 and 183. The second damping force generating mechanisms 173 and 183 have a sub-valve 171 provided on one side of the second passages 172 and 182 formed in the valve seat member 105 and a sub-valve 181 provided on the other side. The second damping-force generating mechanism 183 has a cap member 108. The sub-valve 181, the valve seat member 105, and the passage forming member 382, which are part of the second damping force generating mechanism 183, are housed in the cap member 108.

When the shock absorber 1E according to the sixth embodiment is assembled, the cap member 108, the passage forming member 382, the sub-valve 181, the valve seat member 105, and the seal member 103 are assembled in advance to form the sub-assembly 200E.

In this case, for example, the passage forming member 382 is fitted to the inner cylindrical portion 126 of the cap member 108 in a state where the bottom portion 122 is positioned vertically downward, so that the passage forming member 382 is placed on the bottom portion 122, and the sub valve 181 is placed on the passage forming member 382 by fitting the sub valve 181 to the inner cylindrical portion 126.

Then, the valve seat member 105 with the seal member 103 attached to the outer peripheral portion is fitted together with the seal member 103 to the outer tube portion 124 of the cap member 108, and the intermediate diameter hole 372 is fitted to the inner tube portion 126. Then, the valve seat member 105 sandwiches the sub valve 181 and the passage forming member 382 with the bottom portion 122 of the cap member 108.

When the seal member 103 is inserted into the outer tube portion 124 of the cap member 108 in a state of being attached to the valve seat member 105, a frictional force is generated between both the valve seat member 105 and the outer tube portion 124, and the relative axial movement of the valve seat member 105 and the cap member 108 is regulated, as in the first embodiment. As a result, the intermediate diameter hole 372 and the inner tube portion 126 are maintained in the fitted state. Therefore, the valve seat member 105 restricts the sub valve 181 and the passage forming member 382 fitted to the inner tube portion 126 from being detached from the inner tube portion 126. Thus, the sub valve 181 and the passage forming member 382 are maintained in a state of being fitted to the inner cylinder portion 126, and are therefore maintained in a state of being positioned in the radial direction with respect to the cap member 108 and being restricted from being displaced in the radial direction. In this way, the cap member 108, the sub-valve 181, the passage forming member 382, the valve seat member 105, and the seal member 103 form the sub-assembly 200E.

In the shock absorber 1E of the sixth embodiment, for example, the first damping force generating mechanism 42 is opened during the expansion stroke, and the hydraulic fluid flows from the upper chamber 19 to the lower chamber 20 through the first passage 92.

During the extension stroke, for example, the oil flows from the upper chamber 19 to the lower chamber 20 via the passage in the passage hole 362 constituting the second passage 182, the passage in the passage forming member 381, the passage in the large-diameter hole portion 373 of the seat member 105, the passage in the through hole 351 of the cap member 108, the passage in the guide port 311 of the mounting shaft constituting member 302, the passage in the stopper port 342 of the stopper member 321, and the passage on the inner peripheral side of the mounting shaft constituting member 302. At this time, the amount of communication between the passage in the guide port 311 of the mounting shaft portion constituting member 302 and the passage in the stopper port 342 of the stopper member 321 is changed by the driving of the electric driving portion 322, and the damping force is adjusted.

In addition, for example, during the extension stroke, the oil flows from the upper chamber 19 to the lower chamber 20 via the passage in the passage hole 362 constituting the second passage 182, the passage of the second damping force generating mechanism 183 that opens the valve, the cap chamber 146, the passage in the passage forming member 382, the passage in the through hole 352 of the cap member 108, the passage in the guide port 312 of the mounting shaft portion constituting member 302, the passage in the stopper port 343 of the stopper member 321, and the passage on the inner peripheral side of the mounting shaft portion constituting member 302. At this time, the amount of communication between the passage in the guide port 312 of the mounting shaft portion component 302 and the passage in the stopper port 343 of the stopper member 321 is changed by the driving of the electric driving portion 322, and the damping force is adjusted.

In the compression stroke, for example, the first damping force generating mechanism 41 is opened, and the oil flows from the lower chamber 20 to the upper chamber 19 through the first passage 72.

For example, in the compression stroke, the oil flows from the lower chamber 20 to the upper chamber 19 via the passage on the inner peripheral side of the mounting shaft portion constituting member 302 and the stopper member 321 constituting the second passage 172, the passage in the stopper port 343 of the stopper member 321, the passage in the guide port 312 of the mounting shaft portion constituting member 302, the passage in the through hole 352 of the cap member 108, the passage in the passage forming member 382, the passage in the cap chamber 146 and the passage hole 361, and the passage of the second damping force generating mechanism 173 that opens the valve. At this time, the amount of communication between the passage in the guide port 312 of the mounting shaft portion component 302 and the passage in the stopper port 343 of the stopper member 321 is changed by the driving of the electric driving portion 322, and the damping force is adjusted.

In the sixth embodiment, as in the first embodiment, the sub assembly 200E and the sub valve 171 can be mounted in the axial direction in the opposite direction to the above while securing the deformation amount of the sub valve 171.

The first to sixth embodiments described above have shown examples in which the present invention is applied to a multi-tube type hydraulic shock absorber, but the present invention is not limited to this, and may be applied to a single-tube type hydraulic shock absorber in which a gas chamber is formed by a slidable partition on the side of the lower chamber 20 in the cylinder 2 opposite to the upper chamber 19 without an outer tube, and various types of shock absorbers including a pressure control valve using a packing valve having a structure in which a seal member is provided in a disc.

A first aspect of the above-described embodiments is a buffer including: a cylinder in which a working fluid is sealed; a piston slidably provided in the cylinder and dividing the cylinder into two chambers; a piston rod coupled to the piston and extending and protruding to the outside of the cylinder; a first passage and a second passage through which a working fluid flows out from the upstream chamber to the downstream chamber in the cylinder by the movement of the piston; a first damping force generating mechanism that is provided in the first passage formed in the piston and generates a damping force; and a second damping force generation mechanism provided in the annular valve seat member disposed in one of the chambers, provided in the second passage parallel to the first passage, and configured to generate a damping force, the second damping force generation mechanism including: a first sub-valve provided on one side of the second passage formed in the valve seat member, and a second sub-valve provided on the other side; and a cap member having a bottomed cylindrical shape and an outer cylindrical portion and a bottom portion, the cap member having an inner cylindrical portion into which the piston rod is insertable, the cap member accommodating at least a part of the second damping force generation mechanism, the inner cylindrical portion being formed on an inner peripheral side of the bottom portion. Thus, productivity can be improved.

A second aspect is the first aspect wherein the second sub-valve and the valve seat member are housed in the cap member, and the valve seat member is capable of being assembled to the cap member by a seal member provided on an outer periphery.

A third aspect is the first aspect wherein the second sub-valve and the valve seat member are housed in the cap member, and an outer periphery of the valve seat member is press-fitted into the cap member.

A fourth aspect is any one of the first to third aspects, wherein a gasket is provided between the bottom portion in the cap member and the second sub-valve.

A fifth aspect is any one of the first to fourth aspects, wherein the cap member includes a first cap member having the outer tube portion and the bottom portion, and a second cap member forming the inner tube portion.

A sixth aspect is any one of the first to fifth aspects, wherein the cap member is formed by press forming.

A seventh aspect is that, in any one of the first to sixth aspects, in a region where the piston speed is low, the second damping force generating mechanism is opened with the first damping force generating mechanism closed, and in a region where the piston speed is higher than the low speed, both the first damping force generating mechanism and the second damping force generating mechanism are opened.

An eighth aspect is the valve control device of any one of the first to seventh aspects, wherein in the second damping force generating mechanism, the valve seat member is provided in the cap member, the first sub-valve is provided in one of the chambers, the second sub-valve is provided in a cap chamber between a bottom portion of the cap member and the valve seat member, and a throttle portion is disposed on an upstream side or a downstream side of a flow of the first sub-valve opening valve in the second passage.

A ninth aspect is any one of the first to sixth aspects, wherein the second damping-force generating mechanism includes: a cylindrical guide member provided on the piston rod and having a guide port on a side wall thereof; a stopper member rotatably fitted in the guide member, the stopper member having a stopper port on a side wall thereof, the stopper port facing the guide port; and a driving unit that drives the stopper member.

Industrial applicability of the invention

By applying the above-described damper to the corresponding field, a damper that can improve productivity can be provided.

Description of the reference numerals

1. 1A-1E buffer

2 Cylinder body

18 piston

19 upper chamber

20 lower chamber (one side chamber)

21 piston rod

41. 42 first damping force generating mechanism

72. 92 first path

103 sealing member

105. 105B, 105C valve seat member

108. 108C, 108D Cap parts

122 bottom

124 outer tube section

126 inner side tube part

146 Cap chamber

171 auxiliary valve (second auxiliary valve)

172. 182 second path

173. 183 second damping force generating mechanism

175. 176 throttling part

181 auxiliary valve (first auxiliary valve)

211 gasket

241 first cap part

242 second cap part

302 mounting shaft component (guide member)

310. 341 side wall

311. 312 boot Port

321 stop part

322 electric drive part (drive unit)

342. 343 stop port