阅读说明：本技术 缓冲器 (Buffer device ) 是由 粟野宏一郎 望月隆久 植村将史 于 2020-02-28 设计创作，主要内容包括：缓冲器(AR)具备：硬质侧阻尼元件(21),其对从压缩侧腔室(Lb)流向伸长侧腔室(La)的液体的流动施加阻力；电磁阀(VR),其可以对绕过硬质侧阻尼元件(21)以连通压缩侧腔室(Lb)和伸长侧腔室(La)的压缩侧旁路通道(3a)的开口面积进行变更；以及软质侧阻尼元件(50),其与电磁阀(VR)串联地设置在压缩侧旁路通道(3a)上；其中,硬质侧阻尼元件(21)构成为具有节流孔(21b)以及与节流孔(21b)并列设置的叶片阀(21a),软质侧阻尼元件(50)构成为具有开口面积比节流孔(21b)大的节流孔(50b)。(The buffer (AR) is provided with: a hard-side damping element (21) that applies resistance to the flow of liquid from the compression-side chamber (Lb) to the extension-side chamber (La); a solenoid Valve (VR) that can change the opening area of a compression-side bypass passage (3a) that bypasses the hard-side damping element (21) to communicate the compression-side chamber (Lb) and the extension-side chamber (La); and a soft-side damping element (50) provided on the compression-side bypass passage (3a) in series with the solenoid Valve (VR); wherein the hard side damping element (21) is configured to have an orifice (21b) and a leaf valve (21a) arranged in parallel with the orifice (21b), and the soft side damping element (50) is configured to have an orifice (50b) having a larger opening area than the orifice (21 b).)

1. A kind of buffer is disclosed, which comprises a buffer body,

it is provided with:

a cylinder;

a piston that is inserted into the cylinder so as to be movable in an axial direction and that divides the cylinder into an expansion-side chamber and a compression-side chamber;

a piston rod having one end protruding outward of the cylinder while being connected to the piston;

a hard-side damping element that applies resistance to a flow of liquid from the compression-side chamber to the extension-side chamber;

a solenoid valve capable of changing an opening area of a bypass passage that bypasses the hard side damping element to communicate the compression side chamber and the extension side chamber;

and a soft-side damping element provided on the bypass passage in series with the solenoid valve;

wherein the hard side damping element is configured to have an orifice and a leaf valve provided in parallel with the orifice,

the soft-side damping element is configured to have a large-diameter orifice having an opening area larger than that of the orifice.

2. The buffer of claim 1, wherein the buffer is a single buffer,

wherein the content of the first and second substances,

the soft-side damping element is configured to have a leaf valve disposed in parallel with the large-diameter orifice.

3. The buffer of claim 1, wherein the buffer is a single buffer,

wherein the content of the first and second substances,

the opening degree of the electromagnetic valve is changed in proportion to the amount of energization.

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

wherein the content of the first and second substances,

the electromagnetic valve has: a cylindrical holder formed with a port connected to the bypass passage; a valve core which can be inserted into the bracket in a reciprocating way and can open and close the port; an urging spring that urges the valve body in one direction of movement of the valve body; and a solenoid that applies a thrust force to the valve body in a direction opposite to the biasing force of the biasing spring.

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

it is provided with:

a liquid storage tank connected to the extended-side chamber;

and a suction valve which allows only a flow of the liquid from the liquid reservoir to the compression-side chamber;

wherein the piston is connected with the other end of the piston rod.

6. The buffer of claim 5, wherein the buffer further comprises a first buffer,

it is provided with:

and a manual valve capable of changing an opening area of a discharge passage for communicating the compression-side chamber and the reservoir tank by manual operation.

Technical Field

The present invention relates to an improvement in a buffer.

Background

Conventionally, in a shock absorber, a cylinder contains a liquid such as hydraulic oil, and when a piston moves in the cylinder, a resistance is applied to the flow of the liquid by a damping element, and a damping force due to the resistance is exerted.

The damper element is configured to include, for example, an orifice and a leaf valve provided in parallel with the orifice. Further, in the case where the piston speed is in the low speed range and the differential pressure between the upstream side and the downstream side of the damping element is smaller than the valve opening pressure of the leaf valve, the liquid flows only through the orifice. On the other hand, when the piston speed is in the medium-high speed range and the differential pressure is equal to or higher than the valve opening pressure of the leaf valve, the liquid flows through the leaf valve.

Therefore, the characteristic of the damping force with respect to the piston speed of the shock absorber (hereinafter referred to as "damping force characteristic") is limited to the opening leaf valve, and changes from the orifice characteristic proportional to the square of the piston speed specific to the orifice to the valve characteristic proportional to the piston speed specific to the leaf valve.

Further, in order to adjust the generated damping force, the shock absorber is provided with a bypass passage that bypasses the damping element, a needle valve that adjusts the opening area of the bypass passage, or a pilot valve that controls the back pressure of a leaf valve constituting the damping element (for example, patent documents 1 and 2).

Documents of the prior art

Patent document

Patent document 1: JP2010-7758A

Patent document 2: JP2014-156885A

Summary of The Invention

Problems to be solved by the invention

For example, in the shock absorber provided with the needle valve described in JP2010-7758A, when the needle valve is driven to increase the opening area of the bypass passage, the flow rate of the liquid flowing through the damping element becomes small, and the generated damping force becomes small (soft mode in fig. 7). In contrast, when the opening area of the bypass passage is reduced, the flow rate of the liquid flowing through the damping element increases, and the generated damping force becomes large (hard mode in fig. 7).

The adjustment of the damping force by such a needle valve is mainly used to adjust the magnitude of the damping force when the piston speed is in a low speed range. Further, when the opening area of the bypass passage is adjusted by the needle valve, the magnitude of the damping force in the medium-high speed range of the piston speed can be adjusted more or less, but it is difficult to increase the adjustment width.

On the other hand, in the shock absorber including the pilot valve described in JP2014-156885a, when the valve opening pressure of the pilot valve is reduced and the back pressure of the leaf valve is reduced, the valve opening pressure of the leaf valve is reduced and the generated damping force is reduced (soft mode in fig. 8). In contrast, when the valve opening pressure of the pilot valve is increased and the back pressure of the leaf valve is increased, the valve opening pressure of the leaf valve becomes large and the generated damping force becomes large (hard mode in fig. 8).

In this way, when the back pressure of the leaf valve is controlled and the valve opening pressure is changed, the adjustment range of the damping force when the piston speed is in the medium-high speed range can be increased. However, in this case, since the characteristic curve indicating the damping force characteristic in the medium-high speed range moves up and down without changing the slope thereof, the slope of the characteristic curve changes abruptly particularly in the hard mode when the low speed range is switched to the medium-high speed range. Therefore, when the shock absorber is mounted on the vehicle, the occupant may feel uncomfortable and ride comfort may be deteriorated.

Therefore, in order to solve these problems, an object of the present invention is to provide a shock absorber capable of increasing the adjustment width of the damping force when the piston speed is in the medium-high speed range and improving the riding comfort when mounted on a vehicle.

Means for solving the problems

The buffer for solving the problem comprises: a hard side damping element that applies resistance to a flow of a liquid flowing from a compression side chamber to an extension side chamber, the compression side chamber being defined by a piston inserted into a cylinder so as to be movable; a solenoid valve capable of changing an opening area of a bypass passage that bypasses the hard-side damping element to communicate the compression-side chamber and the extension-side chamber; and a soft-side damping element provided in series with the solenoid valve in the bypass passage, wherein the hard-side damping element has an orifice and a leaf valve provided in parallel with the orifice, and the soft-side damping element has a large-diameter orifice.

According to the above configuration, when the piston speed is in the low speed range, the characteristic of the damping force generated by the shock absorber is the orifice characteristic specific to the orifice, and when the piston speed is in the medium-high speed range, the characteristic is the valve characteristic specific to the leaf valve. Further, if the opening area of the bypass passage is changed by the solenoid valve, the distribution ratio of the flow rate flowing through each of the hard side damping element and the soft side damping element in the liquid moving from the compression side chamber to the extension side chamber changes, so that both the damping coefficient when the piston speed is in the low speed range and the damping coefficient when the piston speed is in the medium-high speed range can be freely set, and the adjustment range of the generated damping force can be increased.

Further, in the soft mode in which the opening area of the bypass passage is increased, both the damping coefficient when the piston speed is in the low speed range and the damping coefficient when the piston speed is in the medium-high speed range can be reduced. In contrast, in the hard mode in which the opening area of the bypass passage is reduced, both the damping coefficient when the piston speed is in the low speed range and the damping coefficient when the piston speed is in the medium-high speed range can be increased. Accordingly, when the damping force characteristic changes from the orifice characteristic in the low speed range to the valve characteristic in the medium-high speed range, the change in the slope of the characteristic curve is gentle in any mode, and therefore, when the shock absorber according to the present invention is mounted on a vehicle, it is possible to maintain good ride comfort in the vehicle.

In the shock absorber, the soft-side damping element may be configured to have a leaf valve provided in parallel with the large-diameter orifice. Thus, even if a leaf valve having a high valve rigidity is used as the hard-side damping element, the damping force in the soft mode is not excessively large. Therefore, the adjustment width of the damping force when the piston speed is in the medium-high speed range can be further increased.

In the damper, the solenoid valve may be set so that the opening degree thereof changes in proportion to the amount of current supplied. This makes it possible to steplessly adjust the opening area of the bypass passage.

In the damper, the solenoid valve may include: a cylindrical holder formed with a port connected to the bypass passage; a valve core which can be inserted into the bracket in a reciprocating way and can open and close the port; an urging spring that urges the valve body in one direction of movement of the valve body; and a solenoid that applies a thrust force to the valve body in a direction opposite to the biasing force of the biasing spring.

According to the above configuration, the opening degree of the solenoid valve can be easily increased without increasing the stroke amount of the spool as the solenoid valve body, and therefore the adjustment width of the opening area of the bypass passage can be easily increased. Further, the relationship between the opening degree of the solenoid valve and the amount of energization can be easily made a proportional relationship having a positive proportional constant, or can be made a negative proportional relationship having a negative proportional constant.

Further, the buffer may include: a liquid storage tank connected to the extension side chamber while the piston is connected to the other end of the piston rod; and a suction valve which allows only the liquid to flow from the liquid reservoir to the compression-side chamber. According to this configuration, the shock absorber is of a single-rod type, the volume of the piston rod that enters and exits the cylinder can be compensated for by the reservoir tank, and the shock absorber can be a one-way shock absorber that generates a damping force only during the contraction stroke.

Further, the shock absorber may be provided with a manual valve that can be manually operated to change an opening area of a discharge passage for communicating the compression-side chamber and the reservoir tank. According to this structure, even if the electromagnetic valve is closed at the time of failure, the flow rate of the liquid flowing through the hard-side damping element can be reduced by opening only the manual valve. Therefore, it is possible to prevent the damping force from becoming excessively large in the failure mode, and to maintain good riding comfort of the vehicle even in the failure mode when the shock absorber is mounted on the vehicle.

Effects of the invention

According to the shock absorber of the present invention, it is possible to increase the adjustment width of the damping force when the piston speed is in the medium-high speed range, and to improve the riding comfort when mounted on the vehicle.

Drawings

Fig. 1 is a front view schematically showing a state in which a compression-side shock absorber according to an embodiment of the present invention is mounted.

Fig. 2 is a longitudinal sectional view of a compression-side shock absorber as a shock absorber according to an embodiment of the present invention.

Fig. 3 is a longitudinal sectional view showing a part of fig. 2 in an enlarged manner.

Fig. 4 is a hydraulic circuit diagram of a compression-side shock absorber as a shock absorber according to an embodiment of the present invention.

Fig. 5 is a hydraulic circuit diagram of an extension-side shock absorber paired with a compression-side shock absorber as a shock absorber according to an embodiment of the present invention.

Fig. 6 is a damping force characteristic diagram showing a characteristic of a compression side damping force with respect to a piston speed of a compression side shock absorber as a shock absorber according to an embodiment of the present invention.

Fig. 7 is a damping force characteristic diagram showing the characteristic of the damping force with respect to the piston speed of the conventional shock absorber provided with the needle valve.

Fig. 8 is a damping force characteristic diagram showing a characteristic of a damping force with respect to a piston speed of a conventional shock absorber provided with a pilot valve.

Detailed Description

Hereinafter, a buffer according to an embodiment of the present invention will be described with reference to the drawings. The same reference numerals are used throughout the several drawings to designate the same or corresponding components. Further, the shock absorber according to the embodiment of the present invention is used for a front fork that suspends a front wheel of a straddle-type vehicle. In the following description, unless otherwise specified, the up and down in a state where the front fork including the shock absorber is mounted on the vehicle is simply referred to as "up" and "down".

As shown in fig. 1, the front fork F includes a pair of shock absorbers AR, AL, axle-side brackets BR, BL for coupling lower end portions of the shock absorbers AR, AL to an axle of the front wheel W, respectively, and a pair of upper and lower body-side brackets CU, CL for coupling upper end portions of the shock absorbers AR, AL, wherein the body-side brackets CU, CL are coupled by a steering shaft S.

The steering shaft S is rotatably inserted into a head pipe P of the vehicle body, and a handle H is coupled to the upper bracket CU. When the handle H is rotationally operated, the entire front fork F rotates about the steering shaft S. At this time, the front wheel W rotates together with the front fork F, and the direction thereof changes.

In the present embodiment, one of the pair of dampers AR, AL is a compression-side damper AR for generating and adjusting a compression-side damping force, and the damper AR is a damper according to an embodiment of the present invention. Further, the other shock absorber is an extension-side shock absorber AL for generating and adjusting an extension-side damping force. In fig. 1, the compression-side buffer AR is shown on the right side and the extension-side buffer AL is shown on the left side, but these arrangements may be reversed.

First, the compression-side buffer AR as a buffer according to an embodiment of the present invention will be specifically described.

As shown in fig. 2, the compression-side shock absorber AR includes a telescopic pipe member TR having an outer tube 10R and an inner tube 11R slidably inserted into the outer tube 10R. In the present embodiment, the pipe member TR is of an inverted type, the outer pipe 10R is a vehicle-body side pipe for coupling the vehicle-body side brackets CU, CL, and the inner pipe 11R is an axle side pipe for coupling the axle side bracket BR.

When the straddle-type vehicle travels on an uneven road surface or the like and the front wheels W vibrate up and down, the inner tube 11R enters and exits the outer tube 10R, and the tube members TR expand and contract. Thus, the expansion and contraction of the tube member TR is also referred to as expansion and contraction of the damper AR. The pipe member TR may be of an upright type, the outer pipe 10R may be an axle-side pipe, and the inner pipe 11R may be a vehicle-body-side pipe.

Next, the upper end of the outer tube 10R as the upper end of the tube member TR is closed by the cap 12R. On the other hand, the lower end of the inner tube 11R as the lower end of the tube member TR is closed by the axle-side bracket BR. Further, the cylindrical gap formed between the overlapping portions of the outer tube 10R and the inner tube 11R is closed by an annular seal member 13R attached to the lower end of the outer tube 10R and in sliding contact with the outer periphery of the inner tube 11R.

Thus, the inside of the pipe member TR is a closed space, and the damper main body DR is accommodated in the pipe member TR. The buffer body DR has: a cylinder 1R provided in the inner tube 11R; a piston 2R slidably inserted into the cylinder 1R; and a piston rod 3R having a lower end connected to the piston 2R and an upper end protruding outward of the cylinder 1R and connected to the cap 12R.

Since the cap 12R is connected to the outer tube 10R, the piston rod 3R may be connected to the outer tube 10R. Further, the cylinder 1R is connected to the inner pipe 11R. Thus, the damper body DR is interposed between the outer pipe 10R and the inner pipe 11R.

An annular head member 14R is attached to an upper end of the cylinder 1R, and the piston rod 3R is inserted into the head member 14R so as to be movable in the axial direction. The head member 14R slidably supports the piston rod 3R. A suspension spring 15R formed of a coil spring is interposed between the head member 14R and the cover 12R.

When the compression-side shock absorber AR expands and contracts and the inner tube 11R moves in and out of the outer tube 10R, the piston rod 3R moves in and out of the cylinder 1R, and the piston 2R moves up and down (axially) in the cylinder 1R. When the compression-side shock absorber AR contracts and the piston rod 3R enters the cylinder 1R, the suspension spring 15R is compressed to exert an elastic force and urge the compression-side shock absorber AR in the expansion direction. Thus, the suspension spring 15R exerts an elastic force according to the amount of compression, and elastically supports the vehicle body.

The compression-side shock absorber AR of the present embodiment is of a single-rod type, and the piston rod 3R extends outward from one side of the piston 2R toward the cylinder 1R. However, the compression-side shock absorber AR may be a double-rod type in which piston rods extend outward from both sides of the piston toward the cylinder. Further, the piston rod 3R may protrude downward from the cylinder 1R and be coupled to the axle side, and the cylinder 1R may be coupled to the vehicle body side. The suspension spring 15R may be a spring other than a coil spring such as an air spring.

Next, a liquid chamber LR for filling liquid such as hydraulic oil is formed in the cylinder 1R, and the liquid chamber LR is divided into an extension-side chamber La and a compression-side chamber Lb by the piston 2R. The expansion-side chamber here means one of two chambers partitioned by the piston, which is compressed by the piston when the shock absorber expands. On the other hand, the compression-side chamber is one of two chambers divided by the piston, which is compressed by the piston when the shock absorber contracts.

Further, outside the cylinder 1R, more specifically, a space between the damper main body DR and the pipe member TR is a reservoir RR. The liquid reservoir RR stores the same liquid as the liquid in the cylinder 1R, and a gas chamber GR for enclosing a gas such as air is formed above the liquid surface. Thus, the pipe member TR functions as a housing of the reservoir tank 16R for storing liquid, unlike the liquid in the cylinder 1R.

The reservoir chamber RR in the reservoir tank 16R communicates with the extension-side chamber La, and the pressure in the extension-side chamber La is always kept at a pressure (reservoir pressure) substantially equal to the pressure in the reservoir tank 16R (reservoir chamber RR). In addition, the reservoir RR is partitioned from the compression-side chamber Lb by a valve housing 4R fixed to the lower end of the cylinder 1R. A suction passage 4a for communicating the compression-side chamber Lb and the reservoir RR is formed in the valve housing 4R, and a suction valve 40 for opening or closing the suction passage 4a is attached.

The suction valve 40 is an extension-side check valve that opens the suction passage 4a when the compression-side shock absorber AR extends, and allows the liquid in the suction passage 4a to flow from the reservoir RR to the compression-side chamber Lb, but maintains a state in which it closes the suction passage 4a when the compression-side shock absorber AR contracts. The intake valve 40 of the present embodiment is a leaf valve, but may be a poppet valve or the like.

Further, an extension-side passage 2a and a compression-side passage 2b for communicating the extension-side chamber La and the compression-side chamber Lb are formed in the piston 2R, and an extension-side check valve 20 for opening or closing the extension-side passage 2a and a hard-side damping element 21 that applies resistance to the flow of liquid flowing from the compression-side chamber Lb to the extension-side chamber La in the compression-side passage 2b are mounted. The hard side damping element 21 is configured to include a leaf valve 21a stacked on the upper side of the piston 2R, and an orifice 21b (fig. 4) provided in parallel with the leaf valve 21 a.

The leaf valve 21a is a thin annular plate made of metal or the like, or a laminated body in which the annular plates are laminated, has elasticity, and is attached to the piston 2R in a state where the outer peripheral side is allowed to bend. Then, the pressure of the compression-side chamber Lb acts in a direction in which the outer peripheral portion of the leaf valve 21a is bent upward. The orifice 21b is formed by a notch provided in the outer peripheral portion of the leaf valve 21a that is unseated or seated on the valve seat of the piston 2R, an imprint provided on the valve seat, or the like.

When the compression-side shock absorber AR contracts, the compression-side chamber Lb is compressed by the piston 2R, and the internal pressure thereof rises and becomes higher than the pressure of the expansion-side chamber La. When the piston speed is in the low speed range and the differential pressure between the compression-side chamber Lb and the expansion-side chamber La is smaller than the valve opening pressure of the leaf valve 21a when the compression-side shock absorber AR contracts, the liquid flows through the orifice 21b from the compression-side chamber Lb to the expansion-side chamber La, and resistance is applied to the flow of the liquid. When the compression side shock absorber AR contracts, the piston speed increases and falls within the medium-high speed range, and when the differential pressure increases and becomes equal to or greater than the valve opening pressure of the leaf valve 21a, the outer peripheral portion of the leaf valve 21a bends, and the liquid flows from the compression side chamber Lb to the extension side chamber La through the gap formed between the outer peripheral portion and the piston 2R, and resistance is applied to the flow of the liquid.

The hard side damping element 21 configured to include the orifice 21b and the leaf valve 21a arranged in parallel with the orifice 21b is the compression side first damping element that applies resistance to the flow of the liquid flowing from the compression side chamber Lb to the expansion side chamber La when the compression side shock absorber AR contracts. The resistance of the compression-side hard-side damping element 21 is caused by the orifice 21b when the piston speed is in the low speed range, and is caused by the leaf valve 21a when the piston speed is in the medium-high speed range.

On the other hand, the extension-side check valve 20 opens the extension-side passage 2a when the compression-side shock absorber AR extends, and allows the liquid to flow from the extension-side chamber La to the compression-side chamber Lb in the extension-side passage 2a, but maintains a state in which it closes the extension-side passage 2a when the compression-side shock absorber AR contracts. The extension side check valve 20 of the present embodiment is a leaf valve, but may be a poppet valve or the like. Further, if the problem of insufficient suction of the liquid in the cylinder 1R does not occur, the extension-side passage 2a and the extension-side check valve 20 may be omitted.

Next, the piston rod 3R is provided with a damping force adjusting portion for changing the flow rate of the liquid flowing through the hard side damping element 21. The damping force adjustment portion includes: a solenoid valve VR capable of changing an opening area of the compression-side bypass passage 3a that bypasses the hard-side damping element 21 to communicate the extension-side chamber La and the compression-side chamber Lb; and a soft-side damping element 50 provided in series with the solenoid valve VR in the middle of the compression-side bypass passage 3 a.

More specifically, as shown in fig. 3, the piston rod 3R includes: a piston holding member 30R at its front end, a solenoid housing member 31R connected to its tip end side, and a cylindrical rod main body 32R connected to its tip end side and extending outward of the cylinder 1R. The piston holding member 30R includes a bottomed cylindrical case portion 30a and a shaft portion 30b projecting downward from a bottom portion of the case portion 30a, and an annular piston 2R is fixed to an outer periphery of the shaft portion 30b by a nut NR.

Further, a valve housing 5R for dividing the inside thereof into an upper chamber 30c and a lower chamber 30d is fixed to the inner periphery of the cylindrical portion of the housing portion 30 a. A passage 5a for communicating the upper chamber 30c and the lower chamber 30d is formed in the valve housing 5R, and a soft-side damping element 50 is provided in the passage 5 a. Further, a vertical hole 30e that opens downward and communicates with the housing portion 30a is formed in the shaft portion 30b of the piston holding member 30R, and the lower chamber 30d and the compression-side chamber Lb communicate with each other through the vertical hole 30 e.

Next, the solenoid case member 31R includes a cylindrical portion 31a screwed with the upper end outer periphery of the case portion 30 a. A lateral hole 31b that opens laterally is formed in the cylindrical portion 31a, and the extension-side chamber La and the inside of the solenoid case member 31R communicate with each other through the lateral hole 31 b. A solenoid valve VR is provided in the middle of a passage for connecting the cross hole 31b and the upper chamber 30 c.

In the present embodiment, a compression-side bypass passage 3a is formed, which has a horizontal hole 31b, an upper chamber 30c, a lower chamber 30d, and a vertical hole 30e formed in the solenoid housing member 31R or the piston holding member 30R and bypasses the hard-side damping element 21. The solenoid valve VR and the soft side damping element 50 are disposed in series in the middle of the compression side bypass passage 3 a.

The solenoid housing member 31R for housing the solenoid valve VR and the soft-side damping element 50 and the piston holding member 30R have an outer diameter smaller than the inner diameter of the cylinder 1R, and care is taken not to partition the extension-side chamber La with them. The soft-side damping element 50 is configured to have a leaf valve 50a laminated on the upper side of the valve housing 5R, and an orifice 50b (fig. 4) provided in parallel with the leaf valve 50 a.

The leaf valve 50a is a thin annular plate made of metal or the like, or a laminated body in which the annular plates are laminated, has elasticity, and is attached to the valve housing 5R in a state where the outer peripheral side is allowed to bend. Then, the pressure in the lower chamber 30d acts in a direction in which the outer peripheral portion of the leaf valve 50a is bent upward. The orifice 50b is formed by a notch provided in the outer peripheral portion of the leaf valve 50a, an imprint provided on the valve seat, or the like, and the leaf valve is unseated or seated on the valve seat of the valve housing 5R.

When the compression-side shock absorber AR contracts and the solenoid valve VR opens the compression-side bypass passage 3a, the pressure of the lower chamber 30d is higher than that of the upper chamber 30 c. When the piston speed is in the low speed range and the differential pressure between the upper chamber 30c and the lower chamber 30d is smaller than the valve opening pressure of the leaf valve 50a during contraction of the compression side shock absorber AR, the liquid flows through the orifice 50b, flows from the lower chamber 30d to the upper chamber 30c, i.e., from the compression side chamber Lb to the extension side chamber La, and resistance is applied to the flow of the liquid. When the compression side shock absorber AR contracts, the piston speed increases and falls within the medium-high speed range, and when the differential pressure increases and becomes equal to or greater than the valve opening pressure of the leaf valve 50a, the outer peripheral portion of the leaf valve 50a bends, and the liquid flows through the gap formed between the outer peripheral portion and the valve housing 5R, flows from the lower chamber 30d to the upper chamber 30c, that is, from the compression side chamber Lb to the extension side chamber La, and applies resistance to the flow of the liquid.

The soft side damping element 50 configured to include the orifice 50b and the leaf valve 50a arranged in parallel with the orifice 50b is the second compression side damping element that applies resistance to the flow of the liquid flowing from the compression side chamber Lb to the expansion side chamber La in the compression side bypass passage 3a when the compression side shock absorber AR contracts. The resistance of the soft side damping element 50 on the compression side is caused by the orifice 50b when the piston speed is in the low speed range, and is caused by the leaf valve 50a when the piston speed is in the medium-high speed range.

The leaf valve 50a of the soft side damper element 50 has lower valve rigidity (is more flexible) than the leaf valve 21a of the hard side damper element 21, and has a smaller resistance (pressure loss) to the flow of the liquid when the flow rate is the same. In other words, under the same conditions, the liquid flows more easily through the leaf valve 50a than through the leaf valve 21 a. The orifice 50b of the soft side damper element 50 is a large-diameter orifice having a larger opening area than the orifice 21b of the hard side damper element 21, and the resistance (pressure loss) to the flow of the liquid is small when the flow rate is the same.

Next, the solenoid valve VR is configured to include: a cylindrical holder 6R fixed inside the piston rod 3R; a spool 7R reciprocatably inserted into the holder 6R; an urging spring 8R that urges the valve body 7R in one of the movement directions thereof; and a solenoid 9R that applies a thrust force to the valve body 7R in a direction opposite to the biasing force of the biasing spring 8R. Then, the opening degree of the solenoid valve VR is adjusted by changing the position of the valve body 7R in the holder 6R.

More specifically, the bracket 6R is disposed above the valve housing 5R in the piston rod 3R along the center axis of the piston rod 3R in a state where one end in the axial direction is directed upward (toward the solenoid housing member 31R side) and the other end is directed downward (toward the valve housing 5R side). Further, the holder 6R is formed with one or more ports 6a penetrating in the radial direction. The port 6a communicates with the expansion-side chamber La via the cross hole 31b of the solenoid case member 31R, and is opened or closed by the valve body 7R.

The valve body 7R is cylindrical and is slidably inserted into the holder 6R. A plate 70R is laminated on the upper end of the valve body 7R, and a later-described plunger 9a of the solenoid 9R abuts against the plate 70R. On the other hand, the biasing spring 8R abuts on the lower end of the valve body 7R and biases the valve body 7R in a direction of pushing the valve body.

Further, a center hole 7a formed in the center portion of the valve body 7R opens downward and communicates with the upper chamber 30 c. Further, the valve body 7R is formed with an annular groove 7b along its outer circumferential direction, and at least one side hole 7c for communicating the inside of the annular groove 7b with the center hole 7 a. Thereby, the inside of the annular groove 7b communicates with the upper chamber 30c via the side hole 7c and the center hole 7 a.

According to the above configuration, in the case where the valve body 7R is present at the position where the annular groove 7b opposes the port 6a of the holder 6R, the expansion-side chamber La and the upper chamber 30c are allowed to communicate. The state where the annular groove 7b faces the port 6a is a state where the annular groove 7b overlaps the port 6a when viewed in the radial direction, and the opening area of the compression-side bypass passage 3a is changed according to the amount of overlap.

For example, when the amount of overlap of the annular groove 7b with the port 6a increases and the opening degree of the solenoid valve VR increases, the opening area of the compression-side bypass passage 3a increases. Conversely, when the amount of overlap of the annular groove 7b with the port 6a decreases and the opening degree of the solenoid valve VR decreases, the opening area of the compression-side bypass passage 3a decreases. Further, when the spool 7R moves to a position where the annular groove 7b does not completely overlap with the port 6a and closes the electromagnetic valve VR, the communication of the compression-side bypass passage 3a is shut off.

Although not shown in detail, the solenoid 9R of the solenoid valve VR is housed in the solenoid housing member 31R, and includes: a cylindrical stator including a coil; a cylindrical movable core inserted into the stator so as to be movable; and a plunger 9a attached to the inner periphery of the movable core and having a tip abutting against the plate 70R. A wire harness 90R for supplying power to the solenoid 9R protrudes outward through the inside of the lever main body 32R and is connected to a power source.

When the solenoid 9R is energized through the wire harness 90R, the movable core is drawn downward, the plunger 9a moves downward, and the valve body 7R is pressed downward against the biasing force of the biasing spring 8R. Then, the annular groove 7b faces the port 6a, and opens the solenoid valve VR. The relationship between the opening degree of the solenoid valve VR and the amount of current supplied to the solenoid 9R is a proportional relationship having a proportional constant, and the opening degree increases as the amount of current supplied increases. Further, when the energization to the solenoid 9R is cut off, the solenoid valve VR is closed.

In this way, the solenoid valve VR of the present embodiment is of a normally closed type, and the valve body 7R as the valve body is biased in the closing direction by the biasing spring 8R, and the valve body 7R is biased in the opening direction by the solenoid 9R. Further, the opening degree increases in proportion to the amount of energization of the solenoid valve VR, and the opening area of the compression-side bypass passage 3a becomes larger as the opening degree increases. Therefore, it can also be said that the opening area of the compression-side bypass passage 3a increases in proportion to the amount of energization to the solenoid valve VR.

Next, the compression-side shock absorber AR of the present embodiment includes the solenoid valve VR, and includes a second damping force adjusting unit for manually adjusting the flow rate of the hard-side damping element 21 in addition to the damping force adjusting unit for automatically adjusting the flow rate of the compression-side hard-side damping element 21. As shown in fig. 2, the second damping force adjustment portion is configured to have a manual valve 41 that is provided at a bottom portion of the compression-side shock absorber AR and that is capable of changing an opening area of the discharge passage 4b for communicating the compression-side chamber Lb and the reservoir RR by manual operation.

The manual valve 41 includes a needle valve body 41a that is unseated or seated on an annular valve seat (not shown) provided in the middle of the discharge passage 4 b. Further, when the manual valve 41 is rotationally operated, the valve body 41a is brought close to or away from the valve seat according to the rotational direction thereof, and the opening area of the discharge passage 4b is adjusted in size. In the present embodiment, when the energization of the solenoid valve VR is normal, the valve body 41a is seated on the valve seat, and the communication of the discharge passage 4b is blocked by the manual valve 41.

As described above, as shown in fig. 4, the compression-side buffer AR includes: a cylinder 1R; a piston 2R slidably inserted into the cylinder 1R and dividing the interior of the cylinder 1R into an extension-side chamber La and a compression-side chamber Lb; a piston rod 3R having a tip end connected to the piston 2R and a tip end protruding outward of the cylinder 1R; and a reservoir tank 16R connected to the extension-side chamber La in the cylinder 1R; the pressure in the extension-side chamber La is the pressure in the reservoir tank.

Further, in the compression-side shock absorber AR, as passages for communicating the expansion-side chamber La and the compression-side chamber Lb, an expansion-side passage 2a, a compression-side passage 2b, and a compression-side bypass passage 3a are provided. An extension side check valve 20 that allows only one-way flow of the liquid from the extension side chamber La to the compression side chamber Lb is provided on the extension side passage 2a, and the liquid flowing from the compression side chamber Lb to the extension side chamber La flows through the compression side passage 2b or the compression side bypass passage 3 a.

The compression-side hard-side damper element 21 is provided in the compression-side passage 2b, and is configured to have an orifice 21b and a leaf valve 21a arranged in parallel therewith and to apply resistance to the flow of the liquid. On the other hand, the compression-side bypass passage 3a is provided with a compression-side soft-side damper element 50 that has an orifice 50b having a larger opening area than the orifice 21b and a leaf valve 50a having a lower valve rigidity than the leaf valve 21a arranged in parallel, and that is configured to reduce the resistance to the flow of the liquid.

Further, a solenoid valve VR is provided in series with the compression-side soft-side damper element 50 in the compression-side bypass passage 3a, and the opening area of the compression-side bypass passage 3a can be changed by adjusting the amount of current supplied to the solenoid valve VR. The solenoid valve VR is of a normally closed type, and is set to increase the opening area of the compression-side bypass passage 3a in proportion to the amount of current.

Further, the compression-side shock absorber AR is provided with a suction passage 4a and a discharge passage 4b as passages for communicating the compression-side chamber Lb and the reservoir tank 16R. A suction valve 40 that allows only one-way flow of the liquid from the reservoir tank 16R to the compression-side chamber Lb is provided in the suction passage 4 a. On the other hand, a normally closed manual valve 41 that is opened and closed by manual operation is provided in the discharge passage 4 b.

Next, an extension-side buffer AL that forms a pair with a compression-side buffer AR as a buffer according to an embodiment of the present invention will be described. In the present embodiment, since the basic configurations of the buffers AR and AL are the same, a description of a specific configuration of the extension-side buffer AL is omitted.

As shown in fig. 5, the extension-side buffer AL includes: a cylinder 1L; a piston 2L slidably inserted into the cylinder 1L and dividing the interior of the cylinder 1L into an extension-side chamber Lc and a compression-side chamber Ld; a piston rod 3L having a tip end connected to the piston 2L and a tip end protruding outward of the cylinder 1L; and a reservoir 16L connected to the compression-side chamber Ld in the cylinder 1L; wherein, the pressure of the compression side chamber Ld is the pressure of the liquid storage tank.

Further, in the extension-side shock absorber AL, as passages for communicating the extension-side chamber Lc and the compression-side chamber Ld, an extension-side passage 2c, a compression-side passage 2d, and an extension-side bypass passage 3b are provided. A compression-side check valve 23 that allows only one-way flow of the liquid from the compression-side chamber Ld to the expansion-side chamber Lc is provided in the compression-side passage 2d, and the liquid flowing from the expansion-side chamber Lc to the compression-side chamber Ld flows through the expansion-side passage 2c or the expansion-side bypass passage 3 b.

The expansion-side port 2c is provided with an expansion-side hard-side damper element 22 that has an orifice 22b and a leaf valve 22a arranged in parallel with the orifice and that applies resistance to the flow of the liquid. On the other hand, the expansion-side soft-side damper element 51, which has an orifice 51b having a larger diameter than the orifice 22b and a leaf valve 51a having a lower valve rigidity than the leaf valve 22a arranged in parallel, and reduces resistance to the flow of the liquid, is provided in the expansion-side bypass passage 3 b.

Further, a solenoid valve VL is provided in series with the soft-side damper element 51 in the extension-side bypass passage 3b, and the opening area of the extension-side bypass passage 3b can be changed by adjusting the amount of current supplied to the solenoid valve VL. The solenoid valve VL is of a normally closed type as well as the solenoid valve VR of the compression-side shock absorber AR, and is set to increase the opening area of the expansion-side bypass passage 3b in proportion to the amount of current flow.

Next, the operation of the front fork F including the compression-side shock absorber AR as the shock absorber according to the embodiment of the present invention and the extension-side shock absorber AL as the pair thereof will be described.

When the respective dampers AR, AL contract, the piston rods 3R, 3L enter the cylinders 1R, 1L, and the pistons 2R, 2L compress the compression-side chambers Lb, Ld. Normally, the manual valve 41 closes the discharge passage 4 b. Therefore, when the compression-side shock absorber AR contracts, the liquid in the compression-side chamber Lb flows through the compression-side passage 2b or the compression-side bypass passage 3a and moves to the extension-side chamber La. A resistance is applied to the flow of the liquid by the hard side damping element 21 or the soft side damping element 50 on the compression side, and a compression side damping force is generated by the resistance.

On the other hand, when the expansion-side shock absorber AL contracts, the compression-side check valve 23 opens, and the liquid in the compression-side chamber Ld flows through the compression-side passage 2d and moves to the expansion-side chamber Lc. At this time, the liquid can flow through the compression-side check valve 23 relatively unimpeded. Further, the compression-side chamber Ld communicates with the tank 16L and maintains the tank pressure. Therefore, the compression-side damping force of the entire front fork F is mainly caused by the compression-side damping force generated by the compression-side shock absorber AR.

When the compression-side shock absorber AR contracts in a normal state, the distribution ratio of the liquid flowing through the compression-side hard-side damping element 21 and the compression-side soft-side damping element 50 changes in accordance with the opening area of the compression-side bypass passage 3a, and the damping coefficient and the generated compression-side damping force are adjusted in magnitude.

Specifically, as described above, the hard side damper element 21 and the soft side damper element 50 on the compression side are respectively configured to have the orifices 21b and 50b and the leaf valves 21a and 50a arranged in parallel therewith. Therefore, the compression-side damping force characteristic is an orifice characteristic proportional to the square of the piston speed specific to the orifice when the piston speed is in the low speed range, and is a valve characteristic proportional to the piston speed specific to the leaf valve when the piston speed is in the medium-high speed range.

Further, when the amount of energization to the solenoid valve VR is increased and the opening degree is increased, the flow rate of the compression-side bypass passage 3a increases, the proportion of the liquid flowing through the hard-side damping element 21 on the compression side decreases, and the proportion of the liquid flowing through the soft-side damping element 50 on the compression side increases. Since the orifice 50b of the soft side damping element 50 is a large-diameter orifice having a larger opening area than the orifice 21b of the hard side damping element 21, when the proportion of the liquid flowing toward the soft side damping element 50 is increased, the damping coefficient is decreased in both the low speed range and the medium and high speed range, and the compression side damping force generated with respect to the piston speed is also decreased. When the amount of current supplied to the solenoid valve VR is maximized, the damping coefficient is minimized, and the compression-side damping force generated with respect to the piston speed is minimized.

In contrast, when the amount of energization to the solenoid valve VR is reduced and the opening degree is reduced, the flow rate of the compression-side bypass passage 3a is reduced, the proportion of the liquid flowing through the hard-side damping element 21 on the compression side is increased, and the proportion of the liquid flowing through the soft-side damping element 50 on the compression side is reduced. Then, the damping coefficient increases in both the low speed range and the middle and high speed range, and the compression-side damping force with respect to the piston speed also becomes large. Further, when the energization to the solenoid valve VR is cut off and the solenoid valve VR is closed, the communication of the compression-side bypass passage 3a is cut off, and therefore, the entire flow rate flows through the compression-side hard-side damping element 21. Thus, the damping coefficient is maximized, and the compression-side damping force generated with respect to the piston speed is maximized.

In this way, when the distribution ratio of the liquid flowing through the hard side damping element 21 and the soft side damping element 50, which are the first and second damping elements on the compression side, is changed by the solenoid valve VR, the damping coefficient changes in magnitude, and as shown in fig. 6, the slope of the characteristic curve representing the damping force characteristic on the compression side changes. The compression-side damping force is adjusted between a hard mode in which the generated damping force is increased while the gradient of the characteristic curve is maximized and a soft mode in which the generated damping force is decreased while the gradient is minimized.

In the soft mode, the slope of the characteristic curve representing the damping force characteristic decreases in both the low-speed range and the middle-high speed range, and in the hard mode, the slope of the characteristic curve representing the damping force characteristic increases in both the low-speed range and the middle-high speed range. Therefore, in any mode, the change in the damping force characteristic from the orifice characteristic to the valve characteristic is gentle.

Further, the soft-side damping element 50 includes a leaf valve 50a having low valve rigidity in parallel with the orifice 50 b. Therefore, the leaf valve 21a as the hard side damping element 21 is a valve having high valve rigidity and high valve opening pressure, and the damping force in the soft mode is not excessively large even if the adjustment range in the direction in which the compression side damping force is increased.

In addition, at the time of failure (abnormal time), the energization of the solenoid valve VR is cut off, and the hard mode is switched. At this time, if the manual valve 41 is opened, the liquid of the compression-side chamber Lb flows not only through the compression-side passage 2b but also through the discharge passage 4b, so the flow rate of the liquid flowing through the compression-side hard-side damping element 21 decreases, and the generated compression-side damping force decreases.

When the compression-side shock absorber AR contracts, a volume of the liquid of the piston rod 3R that has entered the cylinder 1R is discharged from the expansion-side chamber La to the reservoir tank 16R. On the other hand, when the expansion-side shock absorber AL contracts, the liquid of the volume amount of the piston rod 3L that has entered the cylinder 1L is discharged from the compression-side chamber Ld to the reservoir tank 16L.

Conversely, when the respective dampers AR, AL extend, the piston rods 3R, 3L are retracted from the cylinders 1R, 1L, and the pistons 2R, 2L compress the extension-side chambers La, Lc. At this time, in the expansion-side shock absorber AL, the liquid in the expansion-side chamber Lc flows through the expansion-side passage 2c or the expansion-side bypass passage 3b and moves to the compression-side chamber Ld. A resistance is applied to the flow of the liquid by the hard-side damping element 22 on the extension side or the soft-side damping element 51 on the extension side, and an extension-side damping force is generated by the resistance.

On the other hand, when the compression side shock absorber AR extends, the extension side check valve 20 opens, and the liquid in the extension side chamber La flows through the extension side passage 2a and moves to the compression side chamber Lb. At this time, the liquid can flow through the extension-side check valve 20 relatively without resistance. Further, the extension-side chamber La communicates with the tank 16R and maintains the tank pressure. Therefore, the extension-side damping force of the entire front fork F is mainly caused by the extension-side damping force generated by the extension-side shock absorber AL.

When the normal extension-side shock absorber AL extends, the distribution ratio of the liquid flowing through the extension-side hard-side damping element 22 and the extension-side soft-side damping element 51 changes according to the opening area of the extension-side bypass passage 3b, and the damping coefficient and the generated extension-side damping force are adjusted in magnitude.

The hard side damper element 22 and the soft side damper element 51 on the expansion side are configured to have orifices 22b, 51b and leaf valves 22a, 51a arranged in parallel, respectively, similarly to the hard side damper element 21 and the soft side damper element 50 on the compression side, and the orifice 51b of the soft side damper element 51 is a large-diameter orifice having an opening area larger than that of the orifice 22b of the hard side damper element 22.

Therefore, even at the time of elongation, the slope of the characteristic curve representing the damping force characteristic decreases in both the low speed range and the middle and high speed range in the soft mode, and the slope of the characteristic curve representing the damping force characteristic increases in both the low speed range and the middle and high speed range in the hard mode. Therefore, even at the time of extension, the change in the damping force characteristic from the orifice characteristic to the valve characteristic is gentle in any mode.

When the expansion-side shock absorber AL expands, the liquid corresponding to the volume of the piston rod 3L retreating from the cylinder 1L is supplied from the reservoir tank 16L to the compression-side chamber Ld. On the other hand, when the compression-side shock absorber AR extends, the suction valve 40 is opened, and the liquid of the volume amount of the piston rod 3R retreating from the cylinder 1R is supplied from the reservoir tank 16R to the compression-side chamber Lb.

Next, the operational effects of the compression-side shock absorber AR as the shock absorber according to the embodiment of the present invention and the front fork F including the compression-side shock absorber AR and the extension-side shock absorber AL will be described.

The compression-side buffer (buffer) AR according to the present embodiment includes: a cylinder 1R; a piston 2R inserted into the cylinder 1R so as to be movable in the axial direction and dividing the interior of the cylinder 1R into an extension-side chamber La and a compression-side chamber Lb; and a piston rod 3R connected to the piston 2R and having one end protruding outward of the cylinder 1R.

Further, the compression-side buffer AR includes: a hard side damping element 21 that applies resistance to the flow of liquid flowing from the compression side chamber Lb to the extension side chamber La; a solenoid valve VR capable of changing an opening area of a compression-side bypass passage (bypass passage) 3a that bypasses the hard-side damper element 21 to communicate the compression-side chamber Lb and the extension-side chamber La; and a soft-side damping element 50 provided in series with the solenoid valve VR on the compression-side bypass passage 3 a. The hard side damping element 21 is configured to have an orifice 21b and a leaf valve 21a provided in parallel with the orifice 21 b. On the other hand, the soft-side damping element 50 is configured to have an orifice (large-diameter orifice) 50b having a larger opening area than the orifice 21 b.

According to the above configuration, when the piston speed is in the low speed range, the characteristic of the damping force generated when the compression side shock absorber AR contracts is the orifice characteristic specific to the orifice, and when the piston speed is in the medium and high speed range, the characteristic is the valve characteristic specific to the leaf valve. Furthermore, if the opening area of the compression-side bypass passage 3a is changed by the solenoid valve VR, the distribution ratio of the flow rates of the liquid moving from the compression-side chamber Lb to the expansion-side chamber La during contraction of the compression-side shock absorber AR through the hard-side damping element 21 and the soft-side damping element 50 is changed, so that both the damping coefficient in the low speed range and the damping coefficient in the medium/high speed range of the piston speed can be freely set, and the adjustment range of the compression-side damping force in the medium/high speed range of the piston speed can be increased.

Further, in the soft mode in which the opening area of the compression-side bypass passage 3a is increased, both the damping coefficient when the piston speed is in the low speed range and the damping coefficient when the piston speed is in the medium-high speed range become small. On the other hand, in the hard mode in which the opening area of the compression-side bypass passage 3a is reduced, both the damping coefficient when the piston speed is in the low speed range and the damping coefficient when in the medium-high speed range are increased. Therefore, when the compression-side damping force characteristic changes from the orifice characteristic in the low speed range to the valve characteristic in the medium-high speed range, the change in the slope of the characteristic curve is gentle in either mode. As a result, when the shock absorber AR according to the present embodiment is mounted on a vehicle, it is possible to reduce the uncomfortable feeling due to the change in the inclination and maintain good riding comfort of the vehicle.

In the compression-side shock absorber AR of the present embodiment, the soft-side damping element 50 is configured to include the orifice (large-diameter orifice) 50b and the leaf valve 50a provided in parallel with the orifice 50 b. In this way, when the leaf valves 50a are also provided in the soft-side damping element 50, the damping force in the soft mode is not excessively large even if the leaf valves 21a of the hard-side damping element 21 are valves having high valve rigidity and high valve opening pressure. That is, according to the above configuration, a valve having high valve rigidity can be adopted as the leaf valve 21a of the hard side damper element 21. In addition, since the adjustment width of the damping force is increased in a direction to increase the compression-side damping force in this manner, the adjustment width of the compression-side damping force when the piston speed is in the medium-high speed range can be further increased.

In the compression-side shock absorber AR of the present embodiment, the piston 2R is connected to the other end of the piston rod 3R, and is formed into a single-rod type. Further, the compression-side buffer AR includes: a reservoir tank 16R connected to the extension-side chamber La; and a suction valve 40 that allows the liquid to flow only from the reservoir tank 16R to the compression-side chamber Lb. With this configuration, the volume of the piston rod 3R entering and exiting the cylinder 1R can be compensated by the reservoir tank 16R. Further, the compression-side shock absorber AR can be a one-way shock absorber that generates a damping force only in the compression stroke.

The front fork F includes an extension-side shock absorber AL that is a one-way shock absorber that exerts a damping force only during an extension stroke and is paired with the compression-side shock absorber AR, and the amount of extension-side damping force generated can be adjusted by changing the distribution ratio of the flow rates that flow through the hard-side damping element 22 on the extension side and the soft-side damping element 51 on the extension side in the liquid that moves from the extension-side chamber Lc to the compression-side chamber Ld according to the degree of opening of the solenoid valve VL. The hard-side damping element 22 on the expansion side and the soft-side damping element 51 on the expansion side are configured to have orifices 22b, 51b and leaf valves 22a, 51a arranged in parallel with the orifices 22b, 51b, respectively.

Therefore, in the front fork F, the adjustment width of the damping force on both the expansion side and the compression side when the piston speed is in the middle-high speed range can be increased. Further, when the damping force characteristic of the front fork F changes from the orifice characteristic in the low speed range to the valve characteristic in the medium and high speed range, the change in the slope of the characteristic curve is gentle on both the expansion side and the compression side in any mode. Therefore, when the front fork F is mounted on the vehicle, the uncomfortable feeling due to the change in the inclination can be further reduced, and the riding comfort of the vehicle can be improved.

The solenoid valves VR, VL of the respective dampers AR, AL of the present embodiment are set such that the opening degree changes in proportion to the amount of current flow. With this configuration, the opening areas of the compression-side bypass passage 3a and the expansion-side bypass passage 3b can be continuously changed.

The compression-side shock absorber AR of the present embodiment is provided with a manual valve 41 that can be manually operated to change the opening area of the discharge passage 4b for communicating the compression-side chamber Lb and the reservoir tank 16R. According to this structure, even if the electromagnetic valve VR is closed at the time of failure, the generated compression-side damping force can be reduced by only manually opening the manual valve 41. Therefore, the compression-side damping force in the failure mode can be prevented from being excessively large, and good vehicle ride comfort can be maintained.

In the compression-side shock absorber AR of the present embodiment, the solenoid valve VR includes: a cylindrical holder 6R formed with a port 6a connected to the compression-side bypass passage 3 a; a cylindrical spool 7R reciprocatably inserted in the holder 6R and opening and closing the port 6 a; an urging spring 8R that urges the valve body 7R in one of the movement directions of the valve body 7R; and a solenoid 9R that applies a thrust force to the valve body 7R in a direction opposite to the biasing force of the biasing spring 8R.

Here, for example, in the case where a needle valve capable of reciprocating is provided as a valve body, as in the solenoid valve described in JP2010-7758A, and the opening degree is changed by adjusting the size of the gap formed between the tip end of the needle valve and the valve seat, the stroke amount of the valve body needs to be increased in order to increase the adjustment width of the opening degree, but this may not be possible.

Specifically, when the stroke amount of the needle valve is increased, the movable space of the needle valve is increased, and it is difficult to secure the accommodation space. Further, in order to increase the stroke amount of the needle valve, when the stroke amount of the plunger of the solenoid is to be increased, the design of the solenoid needs to be changed, which is very complicated. Further, when the stroke amount of the needle valve is increased without changing the design of the solenoid, a member for increasing the movement amount of the needle valve with respect to the movement amount of the plunger is required, the number of components is increased, and it is difficult to secure the accommodation space.

In contrast, in the solenoid valve VR of the present embodiment, the valve body 7R reciprocally inserted into the cylindrical holder 6R opens and closes the port 6a formed in the holder 6R, thereby opening and closing the solenoid valve VR. Therefore, if the plurality of ports 6a are formed in the circumferential direction of the holder 6R or formed in a long shape in the circumferential direction, the opening degree of the solenoid valve VR can be increased without increasing the stroke amount of the spool 7R as the valve body of the solenoid valve VR. Therefore, it is possible to increase the adjustment width of the opening degree of the solenoid valve VR and easily increase the adjustment width of the compression-side damping force.

Further, according to the above configuration, the relationship between the opening degree of the solenoid valve VR and the energization amount can be easily changed. For example, when the relationship between the opening degree of the solenoid valve VR and the energization amount is a negative proportional relationship and the opening degree is desired to be smaller as the energization amount is larger, the port 6a or the annular groove 7b for opening the port 6a may be disposed at a position at which the port 6a is maximally opened when the energization is not performed.

In this way, the relationship between the opening degree of the solenoid valve VR and the amount of electricity supplied can be freely changed, and whether or not the manual valve 41 is provided can be selected accordingly. The solenoid valve VL of the expansion-side shock absorber AL may have the same configuration as that of the solenoid valve VR of the compression-side shock absorber AR, and the relationship between the solenoid valve VL and the amount of current flow may be appropriately changed. Further, the method of adjusting the compression-side damping force of the extension-side shock absorber AL may be a completely different configuration from that of the compression-side shock absorber AR, and the configuration of the extension-side shock absorber AL may be freely changed.

While the preferred embodiments of the present invention have been illustrated in detail, modifications, variations and changes may be made without departing from the scope of the claims. This application claims priority based on japanese patent application No. 2019-038130 filed on the office on 3/4/2019, the entire contents of which are incorporated herein by reference.

Description of the symbols

AR buffer

La elongation side chamber

Lb compression side chamber

VR solenoid valve

1R cylinder

2R piston

3R piston rod

3a compression side bypass channel (bypass channel)

4b discharge channel

6R support

6a port

7R valve core

8R force application spring

9R solenoid

16R liquid storage tank

21 hard side damping element

21a leaf valve

21b orifice

40 suction valve

41 hand valve

50 soft side damping element

50a leaf valve

50b orifice (large diameter orifice).