阅读说明：本技术 缸体装置以及杆的制造方法 (Cylinder device and method for manufacturing rod ) 是由 小俣靖久 久保直也 小松俊文 赤井育夫 于 2018-09-20 设计创作，主要内容包括：在缸体装置中,杆(41)的一个端部在缸体内与活塞结合,另一个端部从缸体的开口部突出,所述杆(41)具有与滑动接触部件滑动接触的中空的圆筒状部件即第一部件(42)和不与滑动接触部件滑动接触的第二部件(43),第二部件(43)的至少第一部件(42)侧的端部的外径尺寸相对于第一部件(42)的外径尺寸为小径,第一部件(42)的内周部与第二部件(43)的外周部通过基于摩擦的焊接接合而被接合。(In a cylinder device, one end of a rod (41) is coupled to a piston in a cylinder, and the other end protrudes from an opening of the cylinder, the rod (41) has a first member (42) that is a hollow cylindrical member that is in sliding contact with a sliding contact member, and a second member (43) that is not in sliding contact with the sliding contact member, the outer diameter dimension of at least the first member (42) -side end of the second member (43) is smaller than the outer diameter dimension of the first member (42), and the inner circumferential portion of the first member (42) and the outer circumferential portion of the second member (43) are joined by friction-based welding.)

1. A cylinder device is characterized by comprising:

a cylindrical cylinder having an opening at least at one end;

a piston sliding within the cylinder and dividing the cylinder into two chambers;

a rod having one end coupled to the piston in the cylinder and the other end protruding from an opening of the cylinder; and

a sliding contact member that is provided in an opening portion of the cylinder and that is in sliding contact with the rod,

the rod has:

a first member that is a hollow cylindrical member that is in sliding contact with the sliding contact member; and

a second member that is not in sliding contact with the sliding contact member,

at least an outer diameter of an end portion of the second member on the first member side is smaller than an outer diameter of the first member,

the inner peripheral portion of the first member and the outer peripheral portion of the second member are joined by friction-based welding.

2. Cylinder device according to claim 1,

the welded portion between the inner peripheral portion of the first member and the outer peripheral portion of the second member is formed in a cylindrical shape that expands toward the end portion side of the first member.

3. Cylinder device according to claim 1 or 2,

there is a space between the first part and the second part.

4. A method of manufacturing a rod, one end portion of the rod being coupled to a piston that divides a cylindrical cylinder having an opening portion at least at one end into two chambers, the other end portion of the rod protruding through a sliding contact member provided in the opening portion of the cylinder, the method comprising:

a step of preparing a hollow first member and a second member, the first member being a portion of the rod which is in sliding contact with the sliding contact member, the second member being a portion of the rod which is not in sliding contact with the sliding contact member, the second member having a portion whose outer diameter is smaller than the outer diameter of the first member;

a step of bringing an inner peripheral surface of the first member into proximity with an outer peripheral surface of the second member while rotating at least one of the first member and the second member; and

and a step of, after the inner peripheral surface of the first member and the outer peripheral surface of the second member are brought into contact with each other, press-fitting the first member and the second member by a predetermined amount in the axial direction, and joining the first member and the second member by friction welding.

5. The method of manufacturing a rod according to claim 4,

the method includes a step of removing burrs of a welded portion of the second member other than the welded portion joined to the first member by screwing.

6. The method of manufacturing a rod according to claim 4,

the method includes a step of screwing the second member before the step of joining the first member and the second member.

7. A method of manufacturing a rod as claimed in any one of claims 4 to 6,

at least an end portion of the inner peripheral portion of the first member is a conical hole portion.

8. The method of manufacturing a rod according to claim 7,

the angle of the conical hole-shaped portion with respect to the axis of the first member is 3 ° or more and 8 ° or less.

Technical Field

The present invention relates to a cylinder device and a method of manufacturing a rod.

The present application claims priority of Japanese patent application No. 2018-062474, filed in Japan on 3/28.2018, the contents of which are incorporated herein by reference.

Background

There is a technique of producing a rod by frictionally press-bonding two members (see, for example, patent document 1).

Disclosure of Invention

Problems to be solved by the invention

However, it is desirable to facilitate manufacturing in the cylinder device.

Accordingly, an object of the present invention is to provide a cylinder device and a rod manufacturing method that can facilitate manufacturing.

Means for solving the problems

In order to achieve the above object, the cylinder device of the present invention has the following structure: the rod has a first member that is in sliding contact with a sliding contact member and a second member that is not in sliding contact with the sliding contact member, an outer diameter dimension of at least an end portion of the second member on the first member side is smaller than an outer diameter dimension of the first member, and an inner peripheral portion of the first member and an outer peripheral portion of the second member are joined by friction-based welding.

The method for manufacturing a rod of the present invention adopts a structure including: a step of preparing a hollow first member and a second member, the first member being a portion of the rod which is in sliding contact with the sliding contact member, the second member being a portion of the rod which is not in sliding contact with the sliding contact member, the second member having a portion whose outer diameter is smaller than the outer diameter of the first member; a step of bringing an inner peripheral surface of the first member into proximity with an outer peripheral surface of the second member while rotating at least one of the first member and the second member; and a step of, after the inner peripheral surface of the first member and the outer peripheral surface of the second member are brought into contact with each other, press-fitting the first member and the second member by a predetermined amount in the axial direction, and joining the first member and the second member by friction welding.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the cylinder device can be easily manufactured.

Drawings

Fig. 1 is a sectional view showing a cylinder device according to an embodiment of the present invention.

Fig. 2 is an exploded view of a rod of a cylinder device according to an embodiment of the present invention before engagement.

Fig. 3 is a process diagram illustrating a method of manufacturing a rod according to an embodiment of the present invention.

Fig. 4 is a sectional view showing an approach step of the mounting shaft forming member in the method of manufacturing a lever according to the embodiment of the present invention.

Fig. 5 is a sectional view showing an approach step of the mounting shaft forming member in the method of manufacturing a lever according to the embodiment of the present invention.

Fig. 6 is a cross-sectional view showing a state after the mounting shaft portion joining step in the method of manufacturing a lever according to the embodiment of the present invention.

Fig. 7 is a cross-sectional view showing a connecting shaft forming member approaching step in the method of manufacturing a rod according to the embodiment of the present invention.

Fig. 8 is a cross-sectional view showing a connecting shaft forming member approaching step in the method of manufacturing a rod according to the embodiment of the present invention.

Fig. 9 is a cross-sectional view showing a state after a connecting shaft portion joining step in the method of manufacturing a rod according to the embodiment of the present invention.

Fig. 10 is a sectional view showing one end side of a rod of the cylinder device according to the embodiment of the present invention.

Fig. 11 is a sectional view showing the other end side of the rod of the cylinder device according to the embodiment of the present invention.

Fig. 12 is a cross-sectional view showing a modification of the rod of the cylinder device according to the embodiment of the present invention.

Detailed Description

Hereinafter, a cylinder device and a rod manufacturing method according to an embodiment of the present invention will be described with reference to the drawings.

Fig. 1 shows a cylinder device 11 according to the present embodiment. The cylinder device 11 is a shock absorber used for a suspension device of a vehicle such as an automobile or a railway vehicle, and more specifically, a shock absorber used for a strut-type suspension of an automobile. The cylinder device 11 includes: the present invention relates to a hydraulic pump including a cylindrical inner tube 12 in which a working fluid as a working fluid is sealed, and a bottomed cylindrical outer tube 14 which is provided on an outer peripheral side of the inner tube 12 with a diameter larger than that of the inner tube 12 and forms a reservoir chamber 13 between the inner tube 12 and the inner tube 12 in which the working fluid and a working gas as the working fluid are sealed. The inner cylinder 12 and the outer cylinder 14 constitute a double cylindrical cylinder 15.

The outer cylinder 14 is an integrally formed member made of one metal member, and includes: a cylindrical side wall portion 21, a bottom portion 22 that closes one end side in the axial direction of the side wall portion 21, and an opening portion 23 on the side of the side wall portion 21 opposite to the bottom portion 22. In other words, the outer cylinder 14 has an opening 23 on one end side and a bottom 22 on the other end side. The opening 23 on one end side of the outer cylinder 14 is the opening 23 on one end side of the cylinder 15. The inner cylinder 12 is an integrally formed member made of one metal member, and has a cylindrical shape.

The cylinder device 11 includes: a disc-shaped base member 30 fitted to one end portion in the axial direction of the inner cylinder 12, and an annular rod guide 31 (sliding contact member) fitted to the other end portion in the axial direction of the inner cylinder 12 and the side wall portion 21 of the outer cylinder 14 on the axial opening portion 23 side. The inner cylinder 12 is engaged with the bottom 22 of the outer cylinder 14 via the base member 30, and is engaged with the opening 23 side of the side wall 21 of the outer cylinder 14 via the rod guide 31. In this state, the inner cylinder 12 is positioned in the radial direction with respect to the outer cylinder 14.

The cylinder device 11 has an annular seal member 33 (sliding contact member) on the side of the rod guide 31 opposite to the bottom portion 22. The sealing member 33 is also fitted to the inner peripheral portion of the side wall portion 21 on the opening portion 23 side, similarly to the rod guide 31. A caulking portion 34 that is plastically deformed radially inward by crimping is formed at an end portion of the side wall portion 21 opposite to the bottom portion 22, and the seal member 33 is sandwiched between the caulking portion 34 and the rod guide 31. The sealing member 33 seals the opening 23 side of the outer cylinder 14, that is, the opening 23 side of the cylinder 15.

The cylinder device 11 has a piston 35 disposed within the cylinder 15. The piston 35 is slidably fitted into the inner cylinder 12 attached to the cylinder 15. The piston 35 slides within the inner cylinder 12 of the cylinder 15, and divides the interior of the inner cylinder 12 into two chambers, a first chamber 38 and a second chamber 39. The first chamber 38 is provided between the piston 35 and the rod guide 31 in the inner cylinder 12, and the second chamber 39 is provided between the piston 35 and the base member 30 in the inner cylinder 12. The second chamber 39 in the inner cylinder 12 is separated from the storage chamber 13 by the base member 30 provided at one end side of the inner cylinder 12. The first chamber 38 and the second chamber 39 are filled with oil as the working fluid, and the reserve chamber 13 is filled with gas as the working gas and oil as the working fluid.

The cylinder device 11 includes a rod 41, one end of the rod 41 is coupled to the piston 35 in the cylinder 15, and the other end thereof protrudes from the opening 23 of the cylinder 15. The lever 41 has: a main shaft portion 42 (first member) at the middle in the axial direction, a mounting shaft portion 43 (second member) at one end in the axial direction, and a coupling shaft portion 44 (second member) at the other end in the axial direction. The mounting shaft 43 projects outward in the axial direction from one end of the main shaft 42 in the axial direction, and the coupling shaft 44 projects outward in the axial direction from the other end of the main shaft 42 in the axial direction. In the cylinder device 11, for example, the rod 41 is attached to the vehicle body side at the attachment shaft portion 43, and the outer cylinder 14 of the cylinder 15 is attached to the wheel side.

The outer peripheral surface of the main shaft 42 has a cylindrical main outer peripheral portion 51. The outer peripheral portion of the main shaft portion 42 is mainly the main outer peripheral portion 51, and a tapered portion 52 whose outer peripheral surface is formed of a tapered surface is formed at an end portion on the coupling shaft portion 44 side in the axial direction. In the main shaft portion 42, one end portion 53 of the end portion on the side of the attachment shaft portion 43 in the axial direction has an end surface expanding in the direction orthogonal to the axis, and the other end portion 55 as the end portion on the side of the coupling shaft portion 44 in the axial direction has an end surface expanding in the direction orthogonal to the axis.

A male screw 57 is formed on the outer peripheral portion of the mounting shaft portion 43. The end portion 59 on the opposite side of the main shaft portion 42 in the axial direction of the attachment shaft portion 43 has a flat front end surface extending in the orthogonal direction.

An outer peripheral portion of the coupling shaft portion 44 on the main shaft portion 42 side in the axial direction is a fitting outer peripheral portion 62 having a cylindrical surface with a constant outer peripheral surface, and an outer peripheral portion on the opposite side to the main shaft portion 42 in the axial direction is a male screw 65. The distal end portion 68, which is an end portion of the coupling shaft portion 44 on the opposite side to the main shaft portion 42 in the axial direction, has a flat distal end surface extending in the orthogonal direction.

The piston 35 is coupled to the rod 41 via a nut 71. That is, the piston 35 is fitted to the fitting outer peripheral portion 62 of the coupling shaft portion 44 of the rod 41, and the piston 35 is attached to the rod 41 by screwing the nut 71 to the male screw 65 of the coupling shaft portion 44.

The rod 41 extends from the cylinder 15 to the outside through the rod guide 31 and the seal member 33 provided on the opening 23 side of the cylinder 15. The main shaft portion 42 of the lever 41 is in sliding contact with the lever guide 31 and the seal member 33 at the main outer peripheral portion 51. In other words, the rod guide 31 and the seal member 33 provided in the opening 23 of the cylinder 15 are in sliding contact with the main outer peripheral portion 51 of the rod 41.

Here, the lever 41 is in sliding contact with only the main outer peripheral portion 51 of the main shaft portion 42 with the lever guide 31 and the seal member 33. Therefore, the attachment shaft portion 43 of the lever 41 does not slide in contact with the lever guide 31 nor with the seal member 33. The coupling shaft portion 44 of the lever 41 does not slide in contact with the lever guide 31 nor with the seal member 33.

The rod 41 is guided by the rod guide 31 and moves in the axial direction integrally with the piston 35 with respect to the cylinder 15. The seal member 33 blocks the gap between the outer cylinder 14 and the rod 41, and restricts leakage of the working fluid in the inner cylinder 12, the working gas in the reservoir chamber 13, and the working fluid to the outside. Therefore, the seal member 33 is provided in the opening 23 of the cylinder 15 and seals the working fluid sealed in the cylinder 15.

The piston 35 is formed with a passage 74 and a passage 75 that penetrate in the axial direction. Passages 74, 75 may communicate first chamber 38 with second chamber 39. The cylinder device 11 includes an annular disc valve 76 that can close the passage 74 by coming into contact with the piston 35 on the side opposite to the bottom portion 22 in the axial direction of the piston 35. The cylinder device 11 further includes an annular disc valve 77 that can close the passage 75 by coming into contact with the piston 35 on the bottom portion 22 side in the axial direction of the piston 35.

When the rod 41 moves to the contraction side where the amount of entry into the cylinder 15 increases and the piston 35 moves in the direction of narrowing the second chamber 39 so that the pressure in the second chamber 39 becomes higher than the pressure in the first chamber 38 by a predetermined value or more, the disc valve 76 opens the passage 74, and at this time, a damping force is generated. When the rod 41 moves to the extension side where the amount of projection from the cylinder 15 increases and the piston 35 moves in the direction of narrowing the first chamber 38 so that the pressure of the first chamber 38 becomes higher than the pressure of the second chamber 39 by a predetermined value or more, the disc valve 77 opens the passage 75, and at this time, a damping force is generated.

The base member 30 is formed with a passage 82 and a passage 83 that penetrate in the axial direction. The passages 82, 83 may communicate the second chamber 39 with the reservoir chamber 13. The cylinder device 11 includes an annular disk valve 85 that can close the passage 82 by coming into contact with the base member 30 on the bottom portion 22 side in the axial direction of the base member 30, and an annular disk valve 86 that can close the passage 83 by coming into contact with the base member 30 on the side opposite to the bottom portion 22 side in the axial direction of the base member 30.

When the rod 41 moves to the contraction side and the piston 35 moves in the direction to narrow the second chamber 39 so that the pressure of the second chamber 39 becomes higher than the pressure of the reservoir chamber 13 by a predetermined value or more, the disc valve 85 opens the passage 82, and at this time, a damping force is generated. The disc valve 86 is a suction valve as follows: when the rod 41 moves to the expansion side and the piston 35 moves to the first chamber 38 side so that the pressure of the second chamber 39 is lower than the pressure of the reservoir chamber 13, the passage 83 is opened, but at this time, the working fluid is caused to flow from the reservoir chamber 13 into the second chamber 39 substantially without generating a damping force.

Next, a method for manufacturing the rod 41 provided in the cylinder device 11 of the present embodiment will be described.

The main shaft portion 42 of the lever 41 shown in fig. 1 is formed by a main shaft portion forming member 42A (first member) shown in fig. 2, the attachment shaft portion 43 of the lever 41 shown in fig. 1 is formed by an attachment shaft portion forming member 43A (second member) shown in fig. 2, and the coupling shaft portion 44 of the lever 41 shown in fig. 1 is formed by a coupling shaft portion forming member 44A (second member) shown in fig. 2. The main shaft portion forming member 42A, the mounting shaft portion forming member 43A, and the coupling shaft portion forming member 44A are separate members, and they are integrated by welding joining based on friction generated by pressure bonding. In the present embodiment, the example in which both the mounting shaft portion forming member 43A and the coupling shaft portion forming member 44A are integrated with the main shaft portion forming member 42A by friction welding is shown, but the technique of the present embodiment may be applied only to either the mounting shaft portion forming member 43A or the coupling shaft portion forming member 44A.

The main shaft portion forming member 42A is a cylindrical tube, and is hollow over the entire length in the axial direction. The main shaft forming member 42A is joined to the mounting shaft forming member 43A at one axial end of the inner peripheral portion. One end portion of the inner peripheral portion of the main shaft forming member 42A, which is on the side where the attachment shaft forming member 43A is joined in the axial direction, is a one-end conical hole portion 101 (conical hole portion). The one-end conical hole portion 101 has a tapered inner peripheral surface whose outer diameter increases toward the axial direction. In other words, when an axis passing through the center of the inner peripheral surface of the main shaft portion forming member 42A in a cross section perpendicular to the longitudinal direction of the main shaft portion forming member 42A and parallel to the longitudinal direction of the main shaft portion forming member 42A is taken as a reference axis, the maximum value of the radius relating to the reference axis is set to be larger than the radius relating to the reference axis of the main outer peripheral portion 51A in a range of a predetermined region in the direction of the reference axis including one of the one end portion 53A and the other end portion 55A which are the pair of end portions of the main shaft portion forming member 42A and on the inner peripheral side of the main shaft portion forming member 42A. The angle α of the one-end conical hole portion 101 with respect to the central axis of the main shaft portion forming member 42A is 3 ° or more and 8 ° or less.

The main shaft forming member 42A is joined to a coupling shaft forming member 44A at the other end in the axial direction of the inner peripheral portion. The other end of the inner peripheral portion of the main shaft forming member 42A, which is on the side to which the coupling shaft forming member 44A is joined in the axial direction, becomes the other-end conical hole portion 103 (conical hole portion). The other-end conical hole-shaped portion 103 has a tapered inner peripheral surface whose outer diameter increases in the axial direction. The angle β of the other-end conical hole-shaped portion 103 with respect to the central axis of the main shaft portion forming member 42A is 3 ° or more and 8 ° or less.

The main shaft portion forming member 42A has a portion between the one-end conical hole portion 101 and the other-end conical hole portion 103 as an intermediate hole portion 105 having a cylindrical inner peripheral surface with a constant diameter. Further, one end portion 53A of the main shaft portion forming member 42A located at one end in the axial direction has a flat end surface spreading in the orthogonal axis direction, and the other end portion 55A located at the other end in the axial direction has a flat end surface spreading in the orthogonal axis direction. The main outer peripheral portion 51A of the main shaft portion forming member 42A, which is the outer peripheral portion thereof, has a cylindrical planar outer peripheral surface of a constant diameter.

The main outer peripheral portion 51A of the main shaft portion forming member 42A is then machined to form the main outer peripheral portion 51 of the main shaft portion 42 that is in sliding contact with the rod guide 31 and the seal member 33 in the rod 41 shown in fig. 1. Therefore, the main shaft portion forming member 42A then becomes a portion of the rod 41 that is in sliding contact with the rod guide 31 and the seal member 33. Further, the one end portion 53A of the main shaft portion forming member 42A is then machined to become the one end portion 53 of the main shaft portion 42 of the lever 41 shown in fig. 1, and the other end portion 55A is then machined to become the tapered portion 52 and the other end portion 55 of the main shaft portion 42.

The mounting shaft portion forming member 43A is a columnar member, and is solid over the entire length in the axial direction. An outer peripheral portion of one end of the mounting shaft portion forming member 43A, which is on the side to be joined to the main shaft portion forming member 42A in the axial direction, is a conical outer peripheral portion 111. The conical outer peripheral portion 111 has a conical outer peripheral surface whose outer diameter decreases toward the axial direction. The angle γ of the conical outer peripheral portion 111 with respect to the central axis of the attachment shaft portion forming member 43A is 3 ° or more and 8 ° or less.

The outer peripheral portion of the attachment shaft portion forming member 43A other than the conical outer peripheral portion 111 is a cylindrical outer peripheral portion 57A having a cylindrical surface outer peripheral surface with a constant diameter. Further, an end portion 115 of the conical outer peripheral portion 111 of the attachment shaft portion forming member 43A on the side opposite to the cylindrical outer peripheral portion 57A has a flat end surface expanding in the axis orthogonal direction, and an end portion 59A of the cylindrical outer peripheral portion 57A on the side opposite to the conical outer peripheral portion 111 has a flat end surface expanding in the axis orthogonal direction.

The minimum outer diameter d1 of the conical outer peripheral portion 111 of the attachment shaft portion forming member 43A is smaller than the maximum inner diameter d2 of the one-end conical hole portion 101 of the main shaft portion forming member 42A. Thereby, the conical outer peripheral portion 111 can enter the one-end conical hole portion 101. Further, the maximum outer diameter d3 of the conical outer peripheral portion 111 of the attachment shaft portion forming member 43A, i.e., the outer diameter d3 of the cylindrical outer peripheral portion 57A, is larger than the minimum inner diameter d4 of the one-end conical hole portion 101 of the main shaft portion forming member 42A, i.e., the inner diameter d4 of the intermediate hole portion 105. Thus, when entering the tapered hole portion 101, the tapered outer peripheral portion 111 abuts against the tapered hole portion 101 to restrict further entry.

Further, the maximum outer diameter d3 of the conical outer peripheral portion 111 of the attachment shaft portion forming member 43A, i.e., the outer diameter d3 of the cylindrical outer peripheral portion 57A, is smaller than the outer diameter d5 of the main shaft portion forming member 42A, i.e., the outer diameter d5 of the main outer peripheral portion 51A. In this way, the attachment shaft portion forming member 43A is formed to have: a cylindrical outer peripheral portion 57A having an outer diameter d3 smaller than the outer diameter d5 of the main shaft portion forming member 42A, and a conical outer peripheral portion 111 having an outer diameter d1 or more and d3 or less smaller than the outer diameter d5 of the main shaft portion forming member 42A.

The cylindrical outer peripheral portion 57A of the attachment shaft portion forming member 43A is then machined to become the male screw 57 of the attachment shaft portion 43 that does not come into sliding contact with the rod guide 31 and the seal member 33 in the rod 41 shown in fig. 1. Therefore, the shaft portion forming member 43A is attached to a portion of the rod 41 that does not come into sliding contact with the rod guide 31 and the seal member 33. Further, the end portion 59A of the shaft portion forming member 43A is attached and then machined to become the tip portion 59 of the attachment shaft portion 43 in the lever 41.

Here, an angle γ of the conical outer peripheral portion 111 with respect to the central axis of the attachment shaft portion forming member 43A is equal to an angle α of the one-end conical hole portion 101 with respect to the central axis of the main shaft portion forming member 42A, and a length of the conical outer peripheral portion 111 in the axial direction is equal to a length of the one-end conical hole portion 101 in the axial direction. The maximum outer diameter d3 of the conical outer peripheral portion 111 is larger than the maximum inner diameter d2 of the one-end conical hole portion 101 by a predetermined amount. In other words, the dimensional relationship is set in the following manner: when the attachment shaft portion forming member 43A is inserted into the main shaft portion forming member 42A until the conical outer peripheral portion 111 abuts against and stops at the one-end conical hole portion 101, the conical outer peripheral portion 111 protrudes outward by a predetermined amount (for example, 1mm) from the one end portion 53A.

The connecting shaft portion forming member 44A is a columnar member, and is solid over the entire length in the axial direction. An outer peripheral portion of one end of the coupling shaft portion forming member 44A, which is on the side to be joined to the main shaft portion forming member 42A in the axial direction, is a conical outer peripheral portion 121. The conical outer peripheral portion 121 has a conical outer peripheral surface whose outer diameter decreases toward the axial direction. The angle of the conical outer peripheral portion 121 with respect to the central axis of the connecting shaft portion forming member 44A is 3 ° or more and 8 ° or less.

The outer peripheral portion of the connecting shaft portion forming member 44A other than the conical outer peripheral portion 121 is a cylindrical outer peripheral portion 62A having a cylindrical surface outer peripheral surface with a constant diameter. Further, an end 125 of the conical outer peripheral portion 121 of the coupling shaft portion forming member 44A on the side opposite to the cylindrical outer peripheral portion 62A has a flat end surface spreading in the axis orthogonal direction, and an end 68A of the cylindrical outer peripheral portion 62A on the side opposite to the conical outer peripheral portion 121 has a flat end surface spreading in the axis orthogonal direction.

The minimum outer diameter d6 of the conical outer peripheral portion 121 of the connecting shaft portion forming member 44A is smaller than the maximum inner diameter d7 of the conical hole portion 103 at the other end of the main shaft portion forming member 42A. Thereby, the conical outer peripheral portion 121 can enter the other-end conical hole portion 103. Further, the maximum outer diameter d8 of the conical outer peripheral portion 121 of the coupling shaft portion forming member 44A, i.e., the outer diameter d8 of the cylindrical outer peripheral portion 62A, is larger than the minimum inner diameter d4 of the conical hole portion 103 at the other end of the main shaft portion forming member 42A, i.e., the inner diameter d4 of the intermediate hole portion 105. Thus, when entering the other-end conical hole portion 103, the conical outer peripheral portion 121 abuts against the other-end conical hole portion 103 to restrict further entry.

Further, the maximum outer diameter d8 of the conical outer peripheral portion 121 of the coupling shaft portion forming member 44A, i.e., the outer diameter d8 of the cylindrical outer peripheral portion 62A, is smaller than the outer diameter d5 of the main shaft portion forming member 42A, i.e., the outer diameter d5 of the main outer peripheral portion 51A. In this way, the coupling shaft portion forming member 44A is formed to have: a cylindrical outer peripheral portion 62A having an outer diameter d8 smaller than the outer diameter d5 of the main shaft portion forming member 42A, and a conical outer peripheral portion 121 having an outer diameter d6 or more and d8 or less smaller than the outer diameter d5 of the main shaft portion forming member 42A.

The cylindrical outer peripheral portion 62A of the coupling shaft portion forming member 44A is then machined to form the fitting outer peripheral portion 62 and the male screw 65 of the coupling shaft portion 44 that do not come into sliding contact with the rod guide 31 and the seal member 33 in the rod 41 shown in fig. 1. Therefore, the shaft forming member 44A is connected to the rod 41 and then becomes a portion that does not come into sliding contact with the rod guide 31 and the seal member 33. Further, the end portion 68A of the shaft portion forming member 44A is connected and then machined to become the tip end portion 68 of the connecting shaft portion 44 in the rod 41.

Here, the angle of the conical outer peripheral portion 121 with respect to the central axis of the connecting shaft portion forming member 44A is equal to the angle β of the other-end conical hole portion 103 with respect to the central axis of the main shaft portion forming member 42A, and the length of the conical outer peripheral portion 121 in the axial direction is equal to the length of the other-end conical hole portion 103 in the axial direction. The maximum outer diameter d8 of the conical outer peripheral portion 121 is larger than the maximum inner diameter d7 of the other-end conical hole-shaped portion 103 by a predetermined amount. In other words, the dimensional relationship is set in the following manner: when the coupling shaft portion forming member 44A is inserted into the main shaft portion forming member 42A until the conical outer peripheral portion 121 abuts against the other-end conical hole portion 103 and stops, the conical outer peripheral portion 121 protrudes outward by a predetermined amount (for example, 1mm) from the other end portion 55A.

The method of manufacturing the lever 41 of the present embodiment includes: a preparation step S1 shown in fig. 3 of preparing the main shaft portion forming member 42A, the mounting shaft portion forming member 43A, and the coupling shaft portion forming member 44A.

In the manufacturing method of the present embodiment, the mounting shaft portion forming member approaching step S2 shown in fig. 3 is performed after the preparation step S1, and in the mounting shaft portion forming member approaching step S2, the main shaft portion forming member 42A is fixed to the friction welding machine, and in the friction welding machine, as shown in fig. 4, the inner peripheral surface of the one-end conical hole-shaped portion 101 of the main shaft portion forming member 42A is made to approach the outer peripheral surface of the conical outer peripheral portion 111 of the mounting shaft portion forming member 43A while the mounting shaft portion forming member 43A is rotated. In the present embodiment, a method of rotating the attachment shaft portion forming member 43A to bring the attachment shaft portion forming member 43A and the main shaft portion forming member 42A into proximity is described, but the main shaft portion forming member 42A may be rotated to bring the main shaft portion forming member 42A and the attachment shaft portion forming member 43A into proximity.

In the manufacturing method of the present embodiment, as shown in fig. 5, the inner peripheral surface of the one-end conical hole-shaped portion 101 of the main shaft portion forming member 42A is brought into contact with the outer peripheral surface of the conical outer peripheral portion 111 of the mounting shaft portion forming member 43A by the mounting shaft portion approaching step S2 by the friction welding machine, and then, as shown in fig. 3, the mounting shaft portion joining step S3 is performed, in which the main shaft portion forming member 42A and the mounting shaft portion forming member 43A are pressed into contact with each other by a predetermined amount in the axial direction while maintaining the rotational state of the mounting shaft portion forming member 43A, and the main shaft portion forming member 42A and the mounting shaft portion forming member 43A are joined to each other by welding based on the frictional heat generated at this time, while the main shaft portion forming member 42A and the mounting shaft portion forming member 43A are pressed into contact with each other.

Here, the friction welding machine presses the mounting shaft forming member 43A into the fixed main shaft forming member 42A while rotating it. As shown in fig. 5, when the conical outer peripheral portion 111 is in contact with the one-end conical hole portion 101, the one end portion 53A of the conical outer peripheral portion 111 protrudes outward by a predetermined amount (for example, 1mm), and in the attachment shaft portion joining step S3, the attachment shaft portion forming member 43A is press-fitted into the main shaft portion forming member 42A in the axial direction by the predetermined amount as a press-fitting amount. After the press-fitting amount is reached, the rotation of the attachment shaft forming member 43A is stopped and the state is maintained for a certain time.

Then, the inner circumferential portion of the one-end conical hole portion 101 of the main shaft portion forming member 42A and the outer circumferential portion of the conical outer circumferential portion 111 of the attachment shaft portion forming member 43A are integrally solidified after softening and stirring of the material by frictional heat, and as shown in fig. 6, a welded portion 131 is formed. The welded portion 131 is formed between the inner peripheral portion of the main shaft portion forming member 42A and the outer peripheral portion of the attachment shaft portion forming member 43A. The welded portion 131 has a shape substantially similar to the shape of the one-end conical hole portion 101 and the conical outer peripheral portion 111 shown in fig. 5, and is formed in a tubular shape extending toward the one end portion 53A of the main shaft portion forming member 42A. The welded portion 131 includes a burr 132, and the burr 132 protrudes axially outward from the one end portion 53A of the main shaft portion forming member 42A, and radially outward from the cylindrical outer peripheral portion 57A of the attachment shaft portion forming member 43A.

In the manufacturing method of the present embodiment, after the mounting shaft portion joining step S3, a coupling shaft portion forming member approaching step S4 shown in fig. 3 is performed, in which the main shaft portion forming member 42A is fixed to the friction welding machine in the coupling shaft portion forming member approaching step S4, and in the friction welding machine, as shown in fig. 7, the inner peripheral surface of the other end conical hole-shaped portion 103 of the main shaft portion forming member 42A and the outer peripheral surface of the conical outer peripheral portion 121 of the coupling shaft portion forming member 44A are made to approach each other while the coupling shaft portion forming member 44A is rotated.

In the manufacturing method of the present embodiment, after the inner peripheral surface of the conical hole-shaped portion 103 at the other end of the main shaft portion forming member 42A is brought into contact with the outer peripheral surface of the conical outer peripheral portion 121 of the coupling shaft portion forming member 44A in the coupling shaft portion approaching step S4 by the friction welding machine as shown in fig. 8, the coupling shaft portion joining step S5 shown in fig. 3 is performed, and in this coupling shaft portion joining step S5, while the rotation state of the coupling shaft portion forming member 44A is maintained, the main shaft portion forming member 42A and the coupling shaft portion forming member 44A are pressed relatively in the axial direction by a predetermined amount, the main shaft portion forming member 42A and the coupling shaft portion forming member 44A are brought into pressure contact with each other, and the main shaft portion forming member 42A and the coupling shaft portion forming member 44A are joined by welding based on frictional heat generated at this time.

Here, the friction welding machine presses the connection shaft portion forming member 44A into the fixed main shaft portion forming member 42A while rotating it. As shown in fig. 8, when the conical outer peripheral portion 121 and the other-end conical hole portion 103 are in contact with each other, the conical outer peripheral portion 121 protrudes outward beyond the other end portion 55A by a predetermined amount (for example, 1mm), and in the coupling shaft portion joining step S5, the coupling shaft portion forming member 44A is press-fitted into the main shaft portion forming member 42A in the axial direction by the press-fitting amount corresponding to the predetermined amount. Immediately after the press-fitting amount, the rotation of the coupling shaft forming member 44A is stopped and the state is maintained for a certain time.

Then, the inner circumferential portion of the other end conical hole portion 103 of the main shaft portion forming member 42A and the outer circumferential portion of the conical outer circumferential portion 121 of the coupling shaft portion forming member 44A are integrally solidified after softening and stirring of the material by frictional heat, and as shown in fig. 9, a welded portion 133 is formed. The welding portion 133 is formed between the inner peripheral portion of the main shaft portion forming member 42A and the outer peripheral portion of the coupling shaft portion forming member 44A. The welding portion 133 has a shape substantially similar to the shape of the other-end conical hole portion 103 and the conical outer peripheral portion 121 shown in fig. 8, and is formed in a tubular shape extending toward the other end portion 55A of the main shaft portion forming member 42A. The welded portion 133 includes a burr 134, and the burr 134 projects axially outward from the other end portion 55A of the main shaft portion forming member 42A and radially outward from the cylindrical outer peripheral portion 62A of the coupling shaft portion forming member 44A.

As shown in fig. 3, the manufacturing method of the present embodiment performs a machining step S6 after the connecting shaft portion joining step S5. In the machining step S6, a distal end portion forming step is performed on the side in which the end portion 59A of the attachment shaft portion forming member 43A shown in fig. 6 is machined to form the distal end portion 59 of the attachment shaft portion 43 shown in fig. 10. In the machining step S6, a main shaft portion one end portion forming step of machining the one end portion 53A of the main shaft portion forming member 42A shown in fig. 6 to form the one end portion 53 of the main shaft portion 42 shown in fig. 10 is performed. In the machining step S6, a male screw forming step is performed in which the cylindrical outer peripheral portion 57A of the mounting shaft portion forming member 43A shown in fig. 6 is machined to form the male screw 57 of the mounting shaft portion 43 shown in fig. 10.

Here, in the mounting shaft portion joining step S3, as shown in fig. 6, even if the burr 132 is generated by the molten metal protruding outward and solidifying between the one end portion 53A of the main shaft portion forming member 42A and the cylindrical outer peripheral portion 57A of the mounting shaft portion forming member 43A, the burr 132 can be removed by cutting in the main shaft portion one end portion forming step and the male screw forming step of the machining step S6 as shown in fig. 10. That is, the manufacturing method of the present embodiment includes a male screw forming step of performing a screw process on a portion of the mounting shaft forming member 43A other than the welded portion 131 to be joined to the main shaft forming member 42A, and removing the burr 132 of the welded portion 131 at this time. In the male thread forming step, the base portion of the male thread 57 may be formed by cutting, and the male thread 57 may be formed by rolling. In this case, the burr 132 is removed at the time of cutting of the base portion of the male screw 57.

In the machining step S6, the other-side distal end portion forming step of machining the end portion 68A of the coupling shaft portion forming member 44A shown in fig. 9 to form the distal end portion 68 of the coupling shaft portion 44 shown in fig. 11 is performed. In the machining step S6, a main shaft portion other end portion forming step of machining the other end portion 55A of the main shaft portion forming member 42A shown in fig. 9 to form the tapered portion 52 of the main shaft portion 42 and the other end portion 55 shown in fig. 11 is performed. In the machining step S6, a forming step is performed, such as machining the cylindrical outer peripheral portion 62A of the coupling shaft portion forming member 44A shown in fig. 9 to form the fitting outer peripheral portion 62 of the coupling shaft portion 44 and the male screw of the male screw 65 shown in fig. 11.

Here, in the coupling shaft portion joining step S5, as shown in fig. 9, even if the burr 134 is generated by the molten metal protruding outward and solidifying between the other end portion 55A of the main shaft portion forming member 42A and the cylindrical outer peripheral portion 62A of the coupling shaft portion forming member 44A, the burr 134 can be removed by cutting as shown in fig. 11 in the main shaft portion other end portion forming step and the male screw forming step of the machining step S6. That is, the manufacturing method of the present embodiment includes a forming step of performing a thread forming process on a portion of the coupling shaft portion forming member 44A other than the welded portion 133 joined to the main shaft portion forming member 42A, and removing a male thread of the burr 134 of the welded portion 133 at this time. In the step of forming the male screw or the like, the fitting outer peripheral portion 62 and the base portion of the male screw 65 may be formed by cutting, and the male screw 65 may be formed by rolling. In this case, the burr 134 is removed at the time of cutting of the base portion of the fitting outer peripheral portion 62 and the male screw 65.

As shown in fig. 1, the rod 41 manufactured by the manufacturing method of the present embodiment described above includes: a main shaft portion 42 in sliding contact with the rod guide 31 and the seal member 33, and an attachment shaft portion 43 and a coupling shaft portion 44 that are not in sliding contact with the rod guide 31 and the seal member 33. The main shaft portion 42 is solid at the portion into which the attachment shaft portion 43 and the coupling shaft portion 44 are inserted, and the other portion is hollow. The mounting shaft portion 43 and the coupling shaft portion 44 are both solid. The rod 41 has a small outer diameter over the entire length of both the attachment shaft portion 43 and the connection shaft portion 44 relative to the outer diameter of the main shaft portion 42.

As shown in fig. 10, the inner peripheral portion of the main shaft portion 42 of the lever 41 and the outer peripheral portion of the attachment shaft portion 43 are joined by friction welding. The welded portion 131 formed at this time between the inner peripheral portion of the main shaft portion 42 and the outer peripheral portion of the attachment shaft portion 43 has a cylindrical shape whose diameter is expanded toward the one end portion 53 side of the main shaft portion 42. As shown in fig. 11, the inner peripheral portion of the main shaft portion 42 of the lever 41 and the outer peripheral portion of the coupling shaft portion 44 are joined by friction welding. The welded portion 133 formed at this time between the inner peripheral portion of the main shaft portion 42 and the outer peripheral portion of the coupling shaft portion 44 has a cylindrical shape whose diameter expands toward the other end portion 55 of the main shaft portion 42.

Patent document 1 describes a method for producing a rod by frictionally press-bonding a cylindrical member to a mixing member having a cylindrical portion and a columnar portion. In this manufacturing method, the cylindrical member is fixed, the end face of the cylindrical member is brought into contact with the end face of the cylindrical portion of the mixing member while the mixing member is rotated, and pressure is applied to these members to join the cylindrical member and the mixing member. Next, burrs generated at the joint portion at the time of joining are removed by cutting. However, in such a joint, when the rod is in sliding contact with the sliding contact member, careful burr removal is required before a machining process for machining the rod into a final shape. For example, before a machining process for machining a rod into a final shape, a dedicated process for cutting and removing burrs and a waste polishing process for polishing the entire outer peripheral portion including a portion from which the burrs are cut and removed are required.

In contrast, the rod 41 of the cylinder device 11 of the present embodiment includes: a hollow main shaft portion 42 in sliding contact with the rod guide 31 and the seal member 33, and an attachment shaft portion 43 and a connection shaft portion 44 that are not in sliding contact with the rod guide 31 and the seal member 33. Of these, the inner peripheral portion of the main shaft portion 42, the outer peripheral portion of the mounting shaft portion 43, and the outer peripheral portion of the coupling shaft portion 44 are joined by friction-based welding. At this time, the outer diameter of the mounting shaft portion 43 and the coupling shaft portion 44 is smaller than the outer diameter of the main shaft portion 42. Therefore, even if the burrs 132 and 134 are generated by the friction welding, the burrs can be generated at a position that does not reach the main outer peripheral portion 51 of the main shaft portion 42 that is in sliding contact with the rod guide 31 and the seal member 33. Therefore, the burr removal is not performed before the machining step S6 for processing the rod 41 into the final shape, and the burr removal can be performed in a short time. Therefore, the rod 41 of the cylinder device 11 can be easily manufactured, and the number of working steps can be reduced.

That is, the method for manufacturing the rod 41 includes a preparation step S1 of preparing a hollow main shaft portion forming member 42A that is a portion of the rod 41 that is in sliding contact with the rod guide 31 and the seal member 33, and an attachment shaft portion forming member 43A and a coupling shaft portion forming member 44A that are portions of the rod 41 that are not in sliding contact with the rod guide 31 and the seal member 33 and that have an outer diameter smaller than the outer diameter of the main shaft portion forming member 42A. In addition, the method comprises the following steps: an attachment shaft portion forming member approaching step S2 of approaching the inner peripheral surface of the main shaft portion forming member 42A to the outer peripheral surface of the attachment shaft portion forming member 43A while bringing the attachment shaft portion forming member 43A into proximity in the attachment shaft portion forming member approaching step S2; and an attachment shaft portion joining step S3 of, after the inner peripheral surface of the main shaft portion forming member 42A and the outer peripheral surface of the attachment shaft portion forming member 43A are brought into contact with each other in the attachment shaft portion joining step S3, pressing the main shaft portion forming member 42A and the attachment shaft portion forming member 43A by a predetermined amount in the axial direction, and joining the main shaft portion forming member 42A and the attachment shaft portion forming member 43A by friction welding. In addition, the method comprises the following steps: a connection shaft portion forming member approaching step S4 of approaching the inner peripheral surface of the main shaft portion forming member 42A and the outer peripheral surface of the connection shaft portion forming member 44A while rotating the connection shaft portion forming member 44A in the connection shaft portion forming member approaching step S4; and a connection shaft portion joining step S5 of, in the connection shaft portion joining step S5, after the inner peripheral surface of the main shaft portion forming member 42A and the outer peripheral surface of the connection shaft portion forming member 44A are brought into contact, pressing the main shaft portion forming member 42A and the connection shaft portion forming member 44A in the axial direction by a predetermined amount, and joining the main shaft portion forming member 42A and the connection shaft portion forming member 44A by friction welding. This makes it possible to easily manufacture the lever 41 and to easily manufacture the lever 41.

Further, the method of manufacturing the lever 41 includes the male screw forming step of performing the screw processing on the portion of the mounting shaft portion forming member 43A other than the welded portion 131 to which the main shaft portion forming member 42A is joined and removing the burr 132 of the welded portion 131, and therefore, the burr 132 can be removed by the cutting processing together with the screw processing of the mounting shaft portion forming member 43A. Therefore, the burr 132 can be removed without performing a special process. Similarly, the method of manufacturing the lever 41 includes a step of forming the connection shaft portion forming member 44A by performing a thread forming process on a portion other than the welded portion 133 to be joined to the main shaft portion forming member 42A and removing the male thread of the burr 134 of the welded portion 133, and therefore, the burr 134 can be removed by a cutting process together with the thread forming process of the connection shaft portion forming member 44A. Therefore, the burr 134 can be removed without performing a special process. Therefore, the equipment cost and the working man-hour can be reduced.

Further, since the end portions of the inner peripheral portion of the main shaft portion forming member 42A are the one-end conical hole portion 101 and the other-end conical hole portion 103, the inner peripheral portion of the main shaft portion forming member 42A can be favorably joined to the outer peripheral portions of the attachment shaft portion forming member 43A and the coupling shaft portion forming member 44A by friction welding.

Further, the end portion of the inner peripheral portion of the main shaft portion forming member 42A is a one-end conical hole portion 101 and a other-end conical hole portion 103, the end portion of the joint side where the shaft portion forming member 43A is attached is a conical outer peripheral portion 111, and the end portion of the joint side where the shaft portion forming member 44A is connected is also a conical outer peripheral portion 121. Therefore, the inner peripheral portion of the main shaft portion forming member 42A and the outer peripheral portions of the mounting shaft portion forming member 43A and the coupling shaft portion forming member 44A can be more favorably joined by friction welding. Here, in this way, when the inner peripheral portion of the main shaft portion forming member 42A, the inner peripheral portion of the attachment shaft portion forming member 43A, and the inner peripheral portion of the coupling shaft portion forming member 44A are joined by friction welding, the welded portions 131 and 133 are formed in a cylindrical shape expanding toward the end portion side of the main shaft portion 42.

Here, the angle of the one-end conical hole portion 101 and the other-end conical hole portion 103 with respect to the axis of the main shaft portion forming member 42A is 3 ° or more and 8 ° or less. Therefore, the inner peripheral portion of the main shaft portion forming member 42A and the outer peripheral portion of the mounting shaft portion forming member 43A can be more favorably joined by friction-based welding. Further, the inner peripheral portion of the main shaft portion forming member 42A and the outer peripheral portion of the coupling shaft portion forming member 44A can be more favorably joined by friction welding. That is, when the angle of the one-end conical hole portion 101 and the other-end conical hole portion 103 with respect to the axis of the main shaft portion forming member 42A is less than 3 °, the contact of the main shaft portion forming member 42A with the mounting shaft portion forming member 43A and the coupling shaft portion forming member 44A becomes unstable, and the joining can be performed only by about 2 to 5mm even if the conditions are changed, and only burrs grow even if the press-in amount is increased. When the angle is larger than 8 °, the joint area increases, and the torque of the friction welding machine in which the mounting shaft forming member 43A and the coupling shaft forming member 44A rotate with respect to the main shaft forming member 42A increases. If the angle is larger than 8 °, the workpiece is likely to slide, or the motor of the friction welding machine is overloaded. If the angle is larger than 8 °, the thickness of the end portion side of the main shaft portion forming member 42A is reduced, and therefore the main shaft portion 42 may be deformed. These problems can be avoided by setting the angle to 3 ° or more and 8 ° or less.

In the above embodiment, after the mounting shaft portion joining step S3, the coupled shaft portion forming member approaching step S4 is performed. In contrast, the connection shaft-forming-member approaching step S4 and the connection shaft joining step S5 may be performed before the mounting shaft-forming-member approaching step S2 and the mounting shaft joining step S3. The mounting shaft-forming-member approaching step S2 and the mounting shaft coupling step S3, and the coupling shaft-forming-member approaching step S4 and the coupling shaft coupling step S5 may be performed in parallel.

In addition, in the mounting shaft portion forming member approaching step S2 and the mounting shaft portion coupling step S3 of the embodiment, a case where the main shaft portion forming member 42A is fixed and the mounting shaft portion forming member 43A is rotated has been described as an example. In contrast, the mounting shaft forming member 43A may be fixed and the main shaft forming member 42A may be rotated, or both the main shaft forming member 42A and the mounting shaft forming member 43A may be rotated. That is, while at least one of the main shaft portion forming member 42A and the attachment shaft portion forming member 43A is rotated, the inner peripheral surface of the one-end conical hole portion 101 of the main shaft portion forming member 42A and the outer peripheral surface of the conical outer peripheral portion 111 of the attachment shaft portion forming member 43A may be brought into close contact and brought into pressure contact with each other.

Similarly, in the connection shaft portion forming member approaching step S4 and the connection shaft portion coupling step S5 of the embodiment, a case where the main shaft portion forming member 42A is fixed and the connection shaft portion forming member 44A is rotated has been described as an example. In contrast, the coupling shaft forming member 44A may be fixed and the main shaft forming member 42A may be rotated, or both the main shaft forming member 42A and the coupling shaft forming member 44A may be rotated. That is, while at least one of the main shaft portion forming member 42A and the coupling shaft portion forming member 44A is rotated, the inner peripheral surface of the other end conical hole portion 103 of the main shaft portion forming member 42A and the outer peripheral surface of the conical outer peripheral portion 121 of the coupling shaft portion forming member 44A may be brought into close contact and brought into pressure contact with each other.

In the embodiment, the case where the end portion of the inner peripheral portion of the main shaft portion forming member 42A is formed as the one-end conical hole portion 101 and the other-end conical hole portion 103, the end portion of the attachment shaft portion forming member 43A on the side of joining to the main shaft portion forming member 42A is formed as the conical outer peripheral portion 111, and the end portion of the coupling shaft portion forming member 44A on the side of joining to the main shaft portion forming member 42A is also formed as the conical outer peripheral portion 121 has been described as an example. In contrast, the end of the attachment shaft forming member 43A on the joining side may be cylindrical, and the end of the coupling shaft forming member 44A on the joining side may be cylindrical. That is, the one-end conical hole portion 101 and the other-end conical hole portion 103 may be formed at least at the end portion of the inner peripheral portion of the main shaft portion forming member 42A.

In the embodiment, the case where the male screw forming step of forming the male screw 57 of the mounting shaft 43 and the male screw forming step of forming the fitting outer peripheral portion 62 of the coupling shaft 44 and the male screw 65 are performed in the machining step S6 performed after the mounting shaft joining step S3 and the coupling shaft joining step S5 has been described as an example. On the other hand, the male screw 57 of the attachment shaft 43 may be formed in advance in the attachment shaft forming member 43A, and the fitting outer peripheral portion 62 and the male screw 65 of the coupling shaft 44 may be formed in advance in the coupling shaft forming member 44A. After that, the mounting shaft forming member approaching step S2 and the mounting shaft joining step S3 may be performed, and the connection shaft forming member approaching step S4 and the connection shaft joining step S5 may be performed. That is, a step of screwing the mounting shaft portion 43 of the mounting shaft portion forming member 43A may be included before the step of coupling the main shaft portion forming member 42A and the mounting shaft portion forming member 43A. Further, a step of performing a screwing process on the coupling shaft portion 44 of the coupling shaft portion forming member 44A in advance may be included before the step of coupling the main shaft portion forming member 42A and the coupling shaft portion forming member 44A. As described above, even when the burrs 132 and 134 are generated by the friction welding, the burrs can be generated at the position where the burrs do not reach the main outer peripheral portion 51 of the main shaft portion 42 which is in sliding contact with the rod guide 31 and the seal member 33, and therefore, the machining step S6, which is a step subsequent to the mounting shaft portion joining step S3 and the coupling shaft portion joining step S5, can be omitted by performing the screw machining in advance.

In the embodiment, the outer diameter of the entire mounting shaft portion 43 and the coupling shaft portion 44 is smaller than the outer diameter of the main shaft portion 42, but only the outer diameter of the end portion of the portion protruding from the main shaft portion 42 on the side of the main shaft portion 42 may be smaller than the outer diameter of the main shaft portion 42. That is, the outer diameter of the end portion of the mounting shaft 43 and the coupling shaft 44 on the main shaft 42 side, at least the portion protruding from the main shaft 42, may be smaller than the outer diameter of the main shaft 42. For example, as shown in the mounting shaft 43 shown in fig. 12, the mounting shaft 43 may have a large diameter portion 142 having an outer diameter larger than a small diameter portion 141 of an end portion of a portion protruding from the main shaft 42 on the main shaft 42 side and equal to or larger than the outer diameter of the main shaft 42 at a position axially apart from the main shaft 42. In this case, the mounting shaft 43 has an axial space 143 between the large diameter portion 142 and the main shaft 42. The same applies to the coupling shaft 44.

In the embodiment, the outer diameter of the entire main shaft portion 42 is larger than the outer diameters of the mounting shaft portion 43 and the connecting shaft portion 44, but the outer diameter of the portion that does not come into sliding contact with the rod guide 31 and the seal member 33 may be smaller than the portion that comes into sliding contact. That is, the outer diameter of the main shaft portion 42 including the portion in sliding contact with the rod guide 31 and the seal member 33 during assembly may be larger than the outer diameter of the end portion of the attachment shaft portion 43 and the coupling shaft portion 44 on the main shaft portion 42 side of the portion protruding from the main shaft portion 42. Since the outer peripheral portion of the mounting shaft portion 43 is joined to the inner peripheral portion of the main shaft portion 42 by friction welding, at least the outer diameter of the end portion on the mounting shaft portion 43 side is larger than the outer diameter of the end portion on the main shaft portion 42 side of the portion of the mounting shaft portion 43 protruding from the main shaft portion 42. Since the outer peripheral portion of the coupling shaft portion 44 is joined to the inner peripheral portion of the main shaft portion 42 by friction welding, at least the outer diameter of the end portion on the coupling shaft portion 44 side is larger than the outer diameter of the end portion on the main shaft portion 42 side of the portion of the coupling shaft portion 44 protruding from the main shaft portion 42.

In the embodiment, the case where the main shaft portion forming member 42A is hollow over the entire length in the axial direction has been described as an example. On the other hand, at least the portion where the mounting shaft forming member 43A and the coupling shaft forming member 44A are joined may be hollow.

In the embodiment, the cylinder device 11 in which the cylinder 15 has the opening 23 only at one end side is described as an example. In contrast, the present invention can be applied to a cylinder device in which the cylinder 15 has opening portions at both ends. That is, the present invention can be applied to a cylinder device having a cylindrical cylinder having an opening portion at least at one end side.

In the first aspect of the above-described embodiment, the cylinder device includes: a cylindrical cylinder having an opening at least at one end; a piston sliding within the cylinder and dividing the cylinder into two chambers; a rod having one end coupled to the piston in the cylinder and the other end protruding from an opening of the cylinder; and a sliding contact member that is provided in an opening portion of the cylinder and that is in sliding contact with the rod, the rod including: a first member that is a hollow cylindrical member that is in sliding contact with the sliding contact member; and a second member that does not come into sliding contact with the sliding contact member, wherein at least an outer diameter of an end portion of the second member on the first member side is smaller than an outer diameter of the first member, and an inner circumferential portion of the first member and an outer circumferential portion of the second member are joined by friction welding. This makes it possible to facilitate the manufacture of the rod, i.e., the cylinder device including the rod.

In a second aspect, in the first aspect, a welded portion between an inner peripheral portion of the first member and an outer peripheral portion of the second member is formed in a cylindrical shape that expands toward an end portion side of the first member.

A third aspect is the first or second aspect, wherein there is a space between the first member and the second member.

In the method of manufacturing a rod according to the fourth aspect, one end portion of the rod is coupled to a piston that divides a cylindrical cylinder having an opening portion at least at one end into two chambers, and the other end portion of the rod protrudes through a sliding contact member provided in the opening portion of the cylinder, the method of manufacturing a rod including: a step of preparing a hollow first member and a second member, the first member being a portion of the rod which is in sliding contact with the sliding contact member, the second member being a portion of the rod which is not in sliding contact with the sliding contact member, the second member having a portion whose outer diameter is smaller than the outer diameter of the first member; a step of bringing an inner peripheral surface of the first member into proximity with an outer peripheral surface of the second member while rotating at least one of the first member and the second member; and a step of, after the inner peripheral surface of the first member and the outer peripheral surface of the second member are brought into contact with each other, press-fitting the first member and the second member by a predetermined amount in the axial direction, and joining the first member and the second member by friction welding. This can facilitate the manufacture of the lever.

A fifth aspect is the fourth aspect, which includes a step of removing burrs of the welded portion by performing a screw process on a portion of the second member other than the welded portion to which the first member is joined.

A sixth aspect of the present invention provides the fourth aspect, wherein a step of screwing the second member is included before the step of joining the first member and the second member.

Seventh means in any one of the fourth to sixth means, at least an end portion of an inner peripheral portion of the first member is a conical hole portion.

Eighth means in the seventh means, an angle of the conical hole portion with respect to an axis of the first member is 3 ° or more and 8 ° or less.

Industrial applicability

According to the present invention, the cylinder device can be easily manufactured.

Description of the reference numerals

11 cylinder device

15 cylinder body

23 opening part

31 Bar guiding piece (sliding contact parts)

33 sealing member (sliding contact member)

35 piston

38 first chamber

39 second chamber

41 rod

42 Main shaft portion (first member)

42A Main shaft portion Forming part (first part)

43 mounting shaft part (second member)

43A mounting shaft forming member (second member)

44 connecting shaft part (second member)

44A connecting shaft part forming part (second part)

101 one end of conical hole

103 other end conical hole part

131. 133 weld

143 space (c)