JP2012116268A - Hydraulic buffer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the responsiveness so as to immediately control an attitude of a vehicle in response to acceleration and deceleration change of the vehicle.SOLUTION: A hydraulic buffer 10 which is provided with a back pressure applying means 93 for applying pressure to a back pressure chamber of a piston ring 90, is allowed to control an attitude of a vehicle by controlling pressure applied to the back pressure chamber 91 with the back pressure applying means 93 with a vehicle attitude control unit 100 in response to an acceleration and deceleration state of a vehicle.

Description

  The present invention relates to a hydraulic shock absorber (rear cushion unit) that makes it possible to control the attitude of a vehicle.

  As a vehicle rear cushion unit, a piston rod attached to the other of the vehicle body side and the rear wheel support member side is inserted into an oil chamber of a damper case attached to one of the vehicle body side and the rear wheel support member side, and provided on the piston rod. A hydraulic shock absorber in which an oil chamber of a damper case is partitioned into a piston-side oil chamber and a rod-side oil chamber by a piston, and a damping force generator is provided between the piston-side oil chamber of the damper case and the rod-side oil chamber. Is used.

  2. Description of the Related Art Conventionally, in a rear cushion unit, in order to prevent the rear (rear portion of the vehicle) from floating (in other words, a nose dive in which the vehicle tilts forward), as described in Patent Document 1, the rear cushion unit is provided in a hydraulic shock absorber of the rear cushion unit. The piston rod is provided with a through hole that connects the piston side oil chamber and the rod side oil chamber of the damper case, and the flow rate control that controls the flow rate of the oil that moves between the piston side oil chamber and the rod side oil chamber in this through hole. A rod is inserted, a brake fluid pressure chamber is provided on the rear end side of the flow control rod, a brake fluid pressure line is extended from the brake fluid pressure chamber, and this brake fluid pressure line is connected to the master cylinder. Yes.

  By operating the brake pedal, the brake fluid pressure is transmitted through the brake fluid pressure line, and the fluid pressure in the brake fluid pressure chamber becomes high. The brake fluid that has become high pressure in the brake fluid pressure chamber pushes the rear end face of the flow control rod, and the flow rate of oil that moves from the piston side oil chamber to the rod side oil chamber or from the rod side oil chamber to the piston side oil chamber To regulate. When the flow rate of this oil is regulated, the damping force of the hydraulic shock absorber increases. When the damping force of the hydraulic shock absorber is increased, the speed at which the hydraulic shock absorber is extended when the brake is operated can be reduced. If the speed at which the hydraulic shock absorber extends becomes slow, the speed at which the rear part of the vehicle body rises during braking can be slowed, and the rear lift can be prevented.

JP2009-286364

  In the rear cushion unit described in Patent Document 1, the flow rate control rod of the hydraulic shock absorber is interlocked with the brake operation, and the flow rate of the oil moving in the damper case is regulated by the hydraulic shock absorber. The posture of the vehicle is controlled by using the change in the damping force generated.

  Therefore, the posture of the vehicle cannot be controlled until the hydraulic shock absorber strokes after the brake operation and the oil in the damper case moves. The attitude of the vehicle cannot be controlled immediately with the brake operation.

  An object of the present invention is to improve the responsiveness so that the attitude of the vehicle can be immediately controlled in accordance with the acceleration / deceleration change of the vehicle.

  According to the first aspect of the present invention, a piston rod attached to the other of the vehicle body side and the rear wheel support member side is inserted into an oil chamber of a damper case attached to one of the vehicle body side and the rear wheel support member side, and the piston rod is inserted into the piston rod. A hydraulic shock absorber in which the oil chamber of the damper case is partitioned into a piston-side oil chamber and a rod-side oil chamber by a provided piston, and a damping force generator is provided between the piston-side oil chamber of the damper case and the rod-side oil chamber. The piston ring provided on the piston is slidably contacted with the inner periphery of the damper case, and a back pressure chamber sealed against the oil chamber of the damper case is provided on the inner periphery of the piston ring so that the piston ring is elastic. It is made of a material, and is provided with back pressure applying means for applying pressure to the back pressure chamber of the piston ring, and the vehicle posture control device adapts the pressure applied by the back pressure applying means to the back pressure chamber according to the acceleration / deceleration state of the vehicle. By controlling Te, in which so as to permit controlling the attitude of the vehicle.

  According to a second aspect of the present invention, in the first aspect of the invention, the back pressure applying means communicates a hollow portion provided in the piston rod to a back pressure chamber of the piston ring through a communication hole provided in the piston. Then, a plunger is provided in the middle of the hollow portion of the piston rod, and the same hydraulic oil as that loaded in the oil chamber of the damper case is filled on the back pressure chamber side from the plunger of the hollow portion, and is opposed to the plunger of the hollow portion. A hydraulic pressure chamber is provided on the back pressure chamber side, and the vehicle attitude control device increases the hydraulic pressure in the hydraulic pressure chamber in conjunction with the acceleration / deceleration change of the vehicle.

  According to a third aspect of the invention, in the second aspect of the invention, the vehicle attitude control device further includes a brake master cylinder that generates a brake fluid pressure in conjunction with an operation of a brake operation unit, and a brake master cylinder that is connected to the back of the brake master cylinder. And a brake hydraulic pressure line connected to the hydraulic pressure chamber of the pressure applying means.

  According to a fourth aspect of the present invention, in the first aspect of the invention, the back pressure applying means communicates the hollow portion provided in the piston rod to the back pressure chamber of the piston ring through the communication hole provided in the piston. Then, a plunger is provided in the middle of the hollow portion of the piston rod, and the same hydraulic oil as that loaded in the oil chamber of the damper case is filled on the back pressure chamber side from the plunger of the hollow portion, and is opposed to the plunger of the hollow portion. A spring is loaded on the back pressure chamber side, and an electric actuator for pressurizing the spring is provided on the base side of the piston rod. The vehicle attitude control device moves the electric actuator in conjunction with the acceleration / deceleration change of the vehicle. It is designed to be driven.

  The invention according to claim 5 is the invention according to claim 4, wherein the vehicle attitude control device drives an electric actuator by an operation signal of a brake operation unit.

  The invention according to claim 6 is the invention according to claim 4, wherein the vehicle attitude control device drives the electric actuator by a detection signal of an acceleration / deceleration sensor that detects acceleration / deceleration of the vehicle. .

(Claim 1)
(a) The pressure applied by the back pressure applying means to the back pressure chamber is controlled by the vehicle attitude control device according to the acceleration / deceleration state of the vehicle. As a result, the pressure in the back pressure chamber applied by the back pressure applying means pressurizes the piston ring, elastically deforms the piston ring in the diameter expansion direction, and pushes it open. A frictional force can be exerted on the piston ring that is about to slidably contact the inner periphery of the damper case before the oil in the damper case starts to move due to the stroke of the hydraulic shock absorber. The frictional force exerted on the piston ring that is about to slidably contact the inner periphery of the damper case becomes a resistance against the expansion / contraction stroke of the hydraulic shock absorber, and slows the expansion / contraction speed. When the vehicle is decelerated, if the hydraulic shock absorber constituting the rear cushion unit slows down, the rear lift can be prevented. If the speed of the hydraulic shock absorber constituting the rear cushion unit becomes slow during acceleration of the vehicle, the sinking of the rear can be prevented.

  (b) The piston ring is in frictional contact with the inner periphery of the damper case, the friction contact length is long, and the effect of generating frictional force is large.

  (c) The back pressure chamber on the inner periphery of the piston ring is sealed against the oil chamber of the damper case, the back pressure chamber seal is broken, and the fluid inside the back pressure chamber leaks into the oil chamber of the damper case. Even if it comes out, it will not cause oil leakage to the outside.

(Claim 2)
(d) The back pressure applying means communicates the hollow portion provided in the piston rod to the back pressure chamber of the piston ring through the communication hole provided in the piston, and a plunger is provided in the middle of the hollow portion of the piston rod. The same hydraulic oil as that loaded in the oil chamber of the damper case is filled from the hollow plunger to the back pressure chamber side, and a hydraulic pressure chamber is provided to the counter back pressure chamber side from the hollow plunger. The hydraulic pressure of the hydraulic chamber, which is increased by the vehicle attitude control device in conjunction with the acceleration / deceleration change of the vehicle, exerts the hydraulic oil filled in the hollow portion of the piston rod and the communication hole of the piston on the back pressure chamber, Pressing and pushing open, the frictional force (a) described above is generated. At this time, since the same hydraulic oil loaded in the oil chamber of the damper case is filled in the back pressure chamber and pressurizes the piston ring, the sealing of the back pressure chamber is broken and the internal fluid of the back pressure chamber is broken. Even if the hydraulic fluid leaks into the oil chamber of the damper case, the oil chamber of the damper case is not soiled.

(Claim 3)
(e) The vehicle attitude control device of (d) described above connects the brake master cylinder that generates brake fluid pressure in conjunction with the operation of the brake operation unit, and the brake master cylinder to the fluid pressure chamber of the back pressure applying means. Brake fluid pressure line. When the vehicle is decelerated by a brake operation, the speed of extension of the hydraulic shock absorber constituting the rear cushion unit becomes slow, and the rear lifting can be prevented.

(Claim 4)
(f) The back pressure applying means communicates the hollow portion provided in the piston rod to the back pressure chamber of the piston ring through the communication hole provided in the piston, and a plunger is provided in the middle of the hollow portion of the piston rod. Fill the back pressure chamber from the hollow plunger with the same hydraulic oil that was loaded in the oil chamber of the damper case, and load a spring from the hollow plunger to the counter back pressure chamber. An electric actuator for pressurization is provided on the base side of the piston rod. The vehicle attitude control device drives the electric actuator in conjunction with the acceleration / deceleration change of the vehicle, and the spring force of the spring pressurized by this moves the hydraulic oil filled in the hollow portion of the piston rod and the communication hole of the piston. It exerts on the back pressure chamber and presses and opens the piston ring to generate the frictional force (a). At this time, since the same hydraulic oil loaded in the oil chamber of the damper case is filled in the back pressure chamber and pressurizes the piston ring, the sealing of the back pressure chamber is broken and the internal fluid of the back pressure chamber is broken. Even if the hydraulic fluid leaks into the oil chamber of the damper case, the oil chamber of the damper case is not soiled.

(Claim 5)
(g) The vehicle attitude control device of (f) described above drives the electric actuator by an operation signal from the brake operation unit. When the vehicle is decelerated by a brake operation, the speed of extension of the hydraulic shock absorber constituting the rear cushion unit becomes slow, and the rear lifting can be prevented.

(Claim 6)
(h) The vehicle attitude control device of (f) described above drives the electric actuator by the detection signal of the acceleration / deceleration sensor that detects the acceleration / deceleration of the vehicle. When the vehicle is accelerated, the speed of the hydraulic shock absorber constituting the rear cushion unit is reduced, and the rear sinking can be prevented.

FIG. 1 is a schematic diagram illustrating a hydraulic shock absorber according to a first embodiment. FIG. 2 is a sectional view showing the hydraulic shock absorber. FIG. 3 is a cross-sectional view showing a damping force generator for a hydraulic shock absorber. 4 is an enlarged view of a main part of FIG. FIG. 5 is an enlarged view of a main part of FIG. FIG. 6 is a schematic diagram illustrating a hydraulic shock absorber according to the second embodiment. FIG. 7 is a sectional view showing the hydraulic shock absorber. FIG. 8 is an enlarged view of a main part of FIG. FIG. 9 is a sectional view showing a hydraulic shock absorber of a reference example.

Example 1 (FIGS. 1 to 5)
FIG. 1 is a view showing a control of a posture of a vehicle such as a motorcycle by a hydraulic shock absorber 10 constituting a rear cushion unit of the vehicle and a vehicle posture control device 100.

(Hydraulic shock absorber 10)
As shown in FIGS. 1 to 3, the hydraulic shock absorber 10 is pivotally supported by the oil chamber 27 of the damper case 11 attached to the vehicle body side (vehicle body frame or the like) so as to be swingable on the vehicle body frame side. A piston rod 12 attached to a swing arm for supporting the rear wheel is slidably inserted, and a suspension spring 13 is interposed on the outer side of the damper case 11 and the piston rod 12.

  The damper case 11 includes a vehicle body side mounting member 14, and the piston rod 12 includes an axle side mounting member 15. A spring receiver 17 is provided on the outer peripheral portion of the damper case 11, and a spring receiver 18 is provided on the outer side of the piston rod 12. A suspension spring 13 is interposed between the spring receiver 17 and the spring receiver 18. The spring force of the suspension spring 13 absorbs the impact force that the vehicle receives from the road surface.

  As shown in FIG. 2, the damper case 11 includes a rod guide 21 through which the piston rod 12 penetrates at an opening thereof. The rod guide 21 is liquid-tightly inserted into an inner periphery of an outer cylinder 11A (described later) of the damper case 11 via an O-ring (the O-ring is loaded into an annular groove on the outer periphery of the rod guide 21), and an oil seal 22 The piston rod 12 is slidable in a liquid-tight manner in the inner diameter portion including the bush 23 and the dust seal 24.

  The hydraulic shock absorber 10 has a double pipe formed by inserting the inner cylinder 11B into the outer cylinder 11A formed by the damper case 11, and the outer cylinder 11A is connected to the inner periphery of the vehicle body side mounting member 14 via an O-ring. Inserted in a liquid-tight manner, the large outer diameter portion 21A of the rod guide 21 is fitted and fixed to the inner periphery of the lower end of the outer cylinder 11A, and the outer periphery of the lower end of the inner cylinder 11B is fixed to the small outer diameter portion 21B of the rod guide 21. Prepare by fitting. A collar 19 is attached to the upper end of the inner cylinder 11B, and the collar 19 is loaded with an O-ring in an annular groove provided in each of the outer circumferences of two stages, a large outer diameter part and a small outer diameter part. The inner periphery of the upper end of the collar 19 is liquid-tightly press-fitted into the large outer diameter portion of the collar 19, and the small outer diameter portion of the collar 19 is liquid-tightly fitted into the step hole of the vehicle body side mounting member 14. And the piston 25 inserted in the front-end | tip part of the piston rod 12 is fixed with the nut 26, and the oil chamber 27 of the damper case 11 is made piston side oil by the piston 25 slidably inserted in the inner periphery of the inner cylinder 11B. It is partitioned into a chamber 27A and a rod side oil chamber 27B.

  In the hydraulic shock absorber 10, the sub tank 30 is formed integrally with the vehicle body side mounting member 14, and the air chamber 31 and the oil reservoir chamber 32 provided in the sub tank 30 sealed by the cap 30 </ b> A are separated by the bladder 33. An oil reservoir 32 that is pressurized by the pressure of the air chamber 31 that is increased in pressure via an air valve 34 provided in the cap 30A is provided so as to communicate with the oil chamber 27 of the damper case 11. The volume of the piston rod 12 that moves back and forth in the oil chamber 27 of the case 11 (including the volume of the temperature expansion of the oil) is compensated.

  The hydraulic shock absorber 10 includes a damping force generator 40 between the piston side oil chamber 27A and the rod side oil chamber 27B of the damper case 11.

  The damping force generator 40 is inserted from the outside into the valve housing hole 14A provided between the damper case 11 and the sub tank 30 in the vehicle body side mounting member 14 in a state of being assembled into the valve unit 40A shown in FIGS. Has been built.

  The valve unit 40A of the damping force generating device 40 includes a valve piece 41, an inner valve holder 42 that is screwed to a small diameter portion 41A on the inner end side of the valve piece 41, and a large diameter portion 41B on the outer end side of the valve piece 41. Adjuster holder 43 that is abutted on the end surface of the adjuster holder 43 from the outside, and is fluid-tightly fitted on the outer periphery of the adjuster holder 43 from the outside to engage in the axial direction, and is screwed to the large diameter portion 41B of the valve piece 41. A cap 44 to be provided.

  The valve unit 40A of the damping force generator 40 is further provided with two opposed center plates 45 in the center along the axial direction of the outer periphery of the small-diameter portion 41A of the valve piece 41, and the outer periphery of the small-diameter portion 41A of the valve piece 41 The expansion side laminated plate valve 52, the compression side piston 60, and the compression side damping valve 61 are loaded in this order from the side of the step surface with the large diameter portion 41B in the axial direction across the center plate 45, and the end side of the inner valve holder 42 is loaded. The pressure side laminated plate valve 62, the extension side piston 50, and the extension side damping valve 51 are loaded in this order. A set of the extension side laminated plate valve 52, the pressure side piston 60, and the pressure side damping valve 61 and a set of the pressure side laminated plate valve 62, the extension side piston 50, and the extension side damping valve 51 are arranged in line symmetry with the center plate 45 interposed therebetween. In addition, the center plate 45 is clamped and fixed between the step surface of the small diameter portion 41A and the large diameter portion 41B of the valve piece 41 and the end surface of the inner valve holder 42.

  The valve unit 40 </ b> A of the damping force generator 40 is configured such that when the adjuster holder 43 is liquid-tightly fitted to the cap 44 via the O-ring 43 </ b> A loaded in the inner peripheral groove of the cap 44, The large-diameter portion 41B of the valve piece 41 is screwed to the inner periphery of the inner end portion of the cap 44 between the inner end surface of the adjuster holder 43 and the step surface provided on the intermediate outer peripheral portion of the large-diameter portion 41B. The provided annular collar portion 44F is sandwiched, and the valve piece 41, the adjuster holder 43 and the like (portion excluding the cap 44 in the valve unit 40A) are assembled freely with respect to the cap 44. Then, the cap 44 constituting the valve unit 40A is liquid-tightly inserted into the valve housing hole 14A via the O-ring 44A, screwed and fixed. The cap 44 is provided with a rotation operation portion 49 (FIG. 2) having a polygonal outer peripheral surface on the outer periphery of the outer end portion of the outer end side small diameter portion. The rotation operation unit 49 can be configured by a deformed outer peripheral surface provided on the cap 44, a hole, a groove, a knurled part, or the like. The rotation operation unit 49 is locked with a tool and screwed.

  The hydraulic shock absorber 10 is in an assembled state in which the damping force generating device 40 has assembled the valve unit 40A into the valve housing hole 14A as described above, and the adjuster holder 43 is interposed between the O-ring 43A provided on the cap 44. The rotating operation can be performed against the generated frictional force, and the rotating operation can be performed in the valve housing hole 14A of the damper case 11 together with the adjuster holder 43 and the valve piece 41 (portion of the valve unit 40A excluding the cap 44).

  At this time, the adjuster holder 43 is provided with two extension side adjusters 70 and a compression side adjuster 80, and these adjusters 70 and 80 are juxtaposed so as to be adjacent to each other in a plan view of the adjuster holder 43. . The adjuster holder 43 has a display portion 48 (indicated with a TEN character indicating the extension side on the periphery of the expansion side adjuster 70 and a COM character indicating the compression side on the periphery of the compression side adjuster 80 ( (Not shown) is provided on the surface.

  In the valve unit 40A of the damping force generator 40, the two center plates 45 used opposite to each other have a plurality of radial grooves 45A provided radially on the mating surfaces of the perforated plates. Thus, a hole 72A described later is formed.

  The valve unit 40A of the damping force generator 40 is inserted from the outside into the valve housing hole 14A, the front end surface of the inner valve holder 42 is opposed to the bottom surface in the axial direction of the valve housing hole 14A, and the O-ring 44A of the cap 44 is attached. The loaded outer circumference is liquid-tightly fitted into the opening of the valve housing hole 14A and fixed as described later. At this time, the damping force generation device 40 fixes the outer periphery, on which the O-rings of the expansion side piston 50 and the compression side piston 60 are loaded, in a liquid-tight manner to the inner periphery of the valve accommodation hole 14A, and the compression side piston 60 in the valve accommodation hole 14A. The space on the counter-extension side piston side is used as a pressure-extended flow passage 46A communicating with the piston-side oil chamber 27A, and the space on the counter-pressure side piston side of the extension side piston 50 in the valve housing hole 14A is the outer flow of the damper case 11 described later. A common pressure expansion flow passage 46B communicating with the rod side oil chamber 27B via the passage 11C is formed, and an annular space sandwiched between the expansion side piston 50 and the pressure side piston 60 around the center plate 45 in the valve housing hole 14A is formed on the vehicle body side mounting member. The pressure expansion common flow channel 46 </ b> C communicates with the oil reservoir 32 through the communication passage 14 </ b> B provided in FIG. Further, the damping force generating device 40 is provided with an extension side passage 50A (not shown) that is opened and closed by the extension side damping valve 51 and a pressure side passage 50B that is opened and closed by the compression side laminated plate valve 62 in the extension side piston 50. The compression side piston 60 is provided with an expansion side channel 60B that is opened and closed by the expansion side laminated plate valve 52 and a pressure side channel 60A (not shown) that is opened and closed by the compression side damping valve 61. The damping force generating device 40 is connected to the pressure expansion common flow paths 46A, 46B, 46C provided in the vehicle body side mounting member 14, the expansion side flow path 50A, the pressure side flow path 50B provided in the expansion side piston 50, and the pressure side piston 60. The provided expansion side flow path 60B, the pressure side flow path 60A, the outer flow path 11C provided in the annular gap between the outer cylinder 11A and the inner cylinder 11B of the damper case 11, and the hole flow path 11D provided on the lower end side of the inner cylinder 11B. The piston-side oil chamber 27A and the rod-side oil chamber 27B of the damper case 11 are communicated with each other (the piston 25 does not have a flow path for communicating the piston-side oil chamber 27A and the rod-side oil chamber 27B).

  Therefore, in the hydraulic shock absorber 10, in the pressure side stroke, the pressure side flow path (in which the oil in the piston side oil chamber 27A of the damper case 11 flows from the outer flow path 11C of the damper case 11 toward the rod side oil chamber 27B) Pressure-reducing common flow paths 46A, 46B, 46C, pressure-side flow paths 60A, 50B) are provided in the damping force generator 40, and this pressure-side flow path (pressure-reducing common flow paths 46A, 46B, 46C, pressure-side flow paths 60A, 50B). The pressure side damping valve 61 is provided upstream of the pressure side, and the pressure side laminated plate valve 62 is provided on the downstream side. The pressure side damping valve 61 in the pressure side flow path (pressure expansion common flow paths 46A, 46B, 46C, pressure side flow paths 60A, 50B). And the intermediate part of the pressure side laminated plate valve 62 are communicated with the oil reservoir chamber 32 via the pressure expansion shared flow path 46C and the communication path 14B. The compression side damping valve 61 is composed of a laminated body of plate valves and generates a compression side damping force. The pressure side laminated plate valve 62 is formed by attaching a pressure side damping force generating means to the pressure side check valve (the pressure side damping force may be generated by the throttle resistance of the pressure side flow path 50B in which the pressure side laminated plate valve 62 is provided). In addition, it is composed of a laminated body of plate valves, and also fulfills a pressure side damping force generation function as well as a check function that allows only the pressure side flow. The generated damping force of the compression side laminated plate valve 62 is smaller than the generated damping force of the compression side damping valve 61, and the compression side damping force generated by the damping force generating device 40 is generally dependent on the compression side damping valve 61.

  However, the pressure side laminated plate valve 62 may be a simple pressure side check valve not accompanied by a pressure side damping force generating means.

  Further, in the extension stroke, the extension side passage (the pressure extension common passage 46A, the oil in the rod side oil chamber 27B of the damper case 11 flows from the outer passage 11C of the damper case 11 toward the piston side oil chamber 27A). 46B, 46C, extension side flow paths 50A, 60B) are provided in the damping force generating device 40, and upstream of this extension side flow path (pressure extension common flow paths 46A, 46B, 46C, extension side flow paths 50A, 60B). The extension side damping valve 51 is provided on the downstream side, and the extension side laminated plate valve 52 is provided on the downstream side. The extension side damping valve in the extension side flow path (the pressure extension shared flow paths 46A, 46B, 46C, the extension side flow paths 50A, 60B) An intermediate portion between the expansion side laminated plate valve 52 and the expansion side laminated plate valve 52 is communicated with the oil reservoir chamber 32 through the pressure expansion shared flow path 46C and the communication path 14B. The extension side damping valve 51 is formed of a laminated body of plate valves and generates an extension side damping force. The extension side laminated plate valve 52 is formed by attaching an extension side damping force generating means to the extension side check valve (the extension side damping force is generated by the restriction resistance of the extension side flow path 60B provided with the extension side laminated plate valve 52. It is made of a laminated body of plate valves and fulfills a function of generating an extension side damping force as well as a check function that allows only the extension side flow. The generated damping force of the extension side laminated plate valve 52 is smaller than the generated damping force of the extension side damping valve 51, and the extension side damping force generated by the damping force generating device 40 is generally dependent on the extension side damping valve 51.

  However, the extension side laminated plate valve 52 may be a simple extension side check valve that does not include the extension side damping force generation means.

  If desired, the damping force generator 40 includes an extension side damping valve 51 and a compression side damping valve 61 in a hollow part provided on the central axis of the small diameter part 41A to the large diameter part 41B of the valve piece 41 as shown in FIG. By detouring, an extension side bypass flow path 72 and a pressure side bypass flow path 82 that communicate the piston side oil chamber 27A and the rod side oil chamber 27B of the damper case 11 with the oil reservoir chamber 32 may be provided. The extension side damping force can be adjusted by adjusting the opening area of the extension side bypass flow path 72 by the extension side damping force adjustment valve 71 operated from the outside by the extension side adjuster 70 provided in the adjustment holder 43. The expansion side bypass flow path 72 opens to the pressure expansion shared flow path 46B, and also opens to the pressure expansion shared flow path 46C through a hole 72A provided in the valve piece 41 and a hole 72B provided in the center plate 45. The pressure-side damping force can be adjusted by adjusting the opening area of the pressure-side bypass passage 82 by a pressure-side damping force adjusting valve 81 operated from the outside by a pressure-side adjuster 80 provided in the adjustment holder 43. The pressure side bypass flow channel 82 opens to the pressure expansion shared flow channel 46A, and also opens to the pressure expansion shared flow channel 46C through a hole 72A provided in the valve piece 41 and a hole 72B provided in the center plate 45. The extension side adjuster 70 and the pressure side adjuster 80 are spaced apart and juxtaposed so as to be adjacent to each other in a plan view of the adjuster holder 43.

  The extension side adjuster 70 is pivotally liquid-tightly attached to the adjustment holder 43 via an O-ring so that it can be rotated from the outside, and a slider 70A is screwed to the threaded portion of the extension side adjuster 70. The slider 70 </ b> A that is moved by the rotation of the 70 pushes the rod-like base end portion of the expansion side damping force adjustment valve 71, and the distal needle valve of the expansion side damping force adjustment valve 71 is moved with respect to the opening of the expansion side bypass passage 72. Advance and retreat. Further, the compression side adjuster 80 is pivotally attached to the adjustment holder 43 through an O-ring so as to be rotatable from the outside, and the compression side damping force adjustment valve 81 is loosely inserted around the rod of the extension side damping force adjustment valve 71. The threaded portion of the compression side adjuster 80 is screwed to the flange portion, and the tip needle valve of the compression side damping force adjustment valve 81 that moves by the rotation of the compression side adjuster 80 is advanced and retracted relative to the opening of the compression side bypass passage 82. . Between the bulging base end portion of the extension side damping force adjustment valve 71 and the recessed portion provided around the extension side damping force adjustment valve 71 of the compression side damping force adjustment valve 81, the extension side damping force adjustment valve 71 is provided. A compression coil spring 73 is provided to keep the base end portion in pressure contact with the slider 70A. An intermediate shaft portion of the compression side adjuster 80 is inserted into the slider 70A of the extension side adjuster 70 to prevent the slider 70A from rotating. The distal end shaft portion of the expansion side adjuster 70 is inserted into the flange portion of the compression side damping force adjustment valve 81 to prevent the compression side damping force adjustment valve 81 from rotating.

Therefore, the hydraulic shock absorber 10 performs a damping action as follows.
(Pressure side stroke)
The oil in the piston side oil chamber 27A is increased in pressure, and the pressure side damping valve 61 of the pressure side flow path 60A of the pressure side piston 60 of the damping force generating device 40 is pushed open to generate a pressure side damping force. The oil flowing out from the pressure side damping valve 61 to the pressure expansion common flow path 46C is divided into two in the pressure expansion common flow path 46C, and one oil is supplied from the pressure side check valve 62 of the pressure side flow path 50B of the expansion side piston 50 to the damper case 11. The oil flows out into the rod-side oil chamber 27B through the outer flow path 11C of the other oil, and the other oil is discharged into the oil reservoir chamber 32. The other oil discharged to the oil reservoir chamber 32 compensates the oil corresponding to the entry volume of the piston rod 12.

(Extension process)
The oil in the rod side oil chamber 27B is pressurized, and the extension side damping valve 51 of the extension side passage 50A of the extension side piston 50 of the damping force generator 40 is pushed through the outer passage 11C of the damper case 11 to open the extension side. Generates a damping force. The oil flowing out from the expansion side damping valve 51 to the pressure expansion common channel 46C joins with the oil replenished from the oil reservoir 32, and then passes through the expansion side laminated plate valve 52 of the expansion side channel 60B of the compression side piston 60. It flows out to the piston side oil chamber 27A. The oil replenished from the oil reservoir 32 compensates for the retraction volume of the piston rod 12.

  However, the hydraulic shock absorber 10 has the following configuration in order to generate a frictional force by the piston ring 90 of the piston 25 (FIGS. 2 and 5).

  In the hydraulic shock absorber 10, the outer periphery of the piston ring 90 provided in the wide groove on the outer periphery of the piston 25 is in sliding contact with the inner periphery of the damper case 11. A back pressure chamber 91 that is sealed with respect to the oil chambers 27 </ b> A and 27 </ b> B of the damper case 11 is provided on the inner periphery of the piston ring 90. In this embodiment, O-rings 92A and 92B are provided in two loading grooves provided at intervals in the groove width direction at the groove bottom of the wide groove where the piston ring 90 of the piston 25 is provided, and provided in the wide groove. The inner periphery of the piston ring 90 is closely attached to the O-rings 92A and 92B. A back pressure chamber 91 is defined as a gap between the inner periphery of the piston ring 90 and a portion sandwiched between the O-rings 92 </ b> A and 92 </ b> B at the groove bottom of the wide groove of the piston 25.

  In the hydraulic shock absorber 10, the piston ring 90 is made of an elastic material such as Teflon (registered trademark), and back pressure applying means 93 for applying pressure to the back pressure chamber 91 of the piston ring 90 is provided.

  The back pressure applying means 93 communicates the hollow portion 94 provided in the piston rod 12 to the back pressure chamber 91 of the piston ring 90 through the communication hole 95 provided in the piston 25. The piston rod 12 includes a horizontal hole 94 </ b> A that communicates the hollow portion 94 with the communication hole 95. The piston 25 includes an annular groove 95A that communicates the communication hole 95 with the back pressure chamber 91 over the entire circumference sandwiched between the loading grooves of both O-rings 92A and 92B. Note that one end of the hollow portion 94 is closed by a plug 94B.

  Further, the back pressure applying means 93 partitions the middle of the hollow portion 94 of the piston rod 12 with a plunger 96 as shown in FIG. The plunger 96 can slide liquid-tightly on the inner periphery of the hollow portion 94 via an O-ring provided in the outer peripheral groove. The back pressure applying means 93 is filled with the same (same type) hydraulic oil L as that loaded in the oil chambers 27A and 27B of the damper case 11 from the plunger 96 of the hollow portion 94 of the piston rod 12 to the back pressure chamber 91 side. . In addition, a hydraulic pressure chamber 97 </ b> B that encloses brake fluid (brake oil) is provided on the side of the anti-back pressure chamber 91 from the plunger 96 of the hollow portion 94. At this time, the axle-side mounting member 15 is screwed and coaxially coupled to the outer periphery of the end of the piston rod 12 protruding from the damper case 11 to the outside, and is fixed by the lock nut 15A. The axle-side mounting member 15 is provided with a hydraulic chamber 97A that communicates with the hydraulic chamber 97B.

  The vehicle attitude control device 100 makes it possible to control the attitude of the vehicle by controlling the pressure applied by the back pressure applying means 93 to the back pressure chamber 91 according to the acceleration / deceleration state of the vehicle.

  In this embodiment, the vehicle attitude control device 100 is a brake master that generates brake fluid pressure in conjunction with a brake operation applied to a brake operation unit 101 such as a brake pedal (or brake lever) of a vehicle as shown in FIG. The cylinder 102 and a brake hydraulic pressure line 103 (103A, 103B) for connecting the brake master cylinder 102 to the hydraulic pressure chamber 97A of the back pressure applying means 93 are provided. The brake fluid pressure line 103 includes a line 103A for connecting the brake master cylinder 102 to the joint 104, a line 103B for connecting the joint 104 to the hydraulic pressure chamber 97A, and a line for connecting the joint 104 to the brake caliper on the wheel side. 103C. A brake oil cup 105 supplies brake fluid to the brake master cylinder 102.

  Accordingly, in the vehicle attitude control device 100, when the brake master cylinder 102 increases the brake fluid pressure by the brake operation applied to the brake operation unit 101, the brake caliper is activated to brake the vehicle and decelerate the vehicle. Simultaneously with the deceleration of the vehicle by the brake operation, the brake fluid pressure generated by the brake master cylinder 102 reaches the fluid pressure chamber 97A of the back pressure applying means 93 via the brake fluid pressure line 103, and the fluid pressure chamber 97A, The hydraulic pressure of 97B is increased. The hydraulic pressure sealed in the hydraulic pressure chambers 97A and 97B applies the hydraulic oil filled in the hollow portion 94 of the piston rod 12 and the communication hole 95 of the piston 25 to the back pressure chamber 91 and pushes the piston ring 90 open. Press against the inner periphery of the damper case 11. Regardless of whether or not the oil in the damper case 11 moves due to the expansion / contraction stroke of the hydraulic shock absorber 10, the piston ring 90 is pressed against the inner periphery of the damper case 11 to exert a frictional force. The frictional force of the piston ring 90 becomes a resistance against the expansion / contraction stroke of the hydraulic shock absorber 10, suppresses the expansion of the hydraulic shock absorber 10 constituting the rear cushion unit, slows the expansion speed, and prevents the rear lift.

Therefore, according to the present embodiment, the following operational effects can be obtained.
(a) The vehicle attitude control device 100 controls the pressure applied by the back pressure applying means 93 to the back pressure chamber 91 according to the acceleration / deceleration state of the vehicle. As a result, the pressure in the back pressure chamber 91 applied by the back pressure applying means 93 pressurizes the piston ring 90 and elastically deforms and pushes the piston ring 90 in the diameter increasing direction. A frictional force can be exerted on the piston ring 90 that is about to slidably contact the inner periphery of the damper case 11 before the oil in the damper case 11 starts to move due to the stroke of the hydraulic shock absorber. The frictional force exerted on the piston ring 90 trying to slidably contact the inner periphery of the damper case 11 becomes a resistance against the expansion / contraction stroke of the hydraulic shock absorber, and slows the expansion / contraction speed. When the vehicle is decelerated, if the hydraulic shock absorber constituting the rear cushion unit slows down, the rear lift can be prevented. If the speed of the hydraulic shock absorber constituting the rear cushion unit becomes slow during acceleration of the vehicle, the sinking of the rear can be prevented.

  (b) The piston ring 90 is in frictional contact with the inner periphery of the damper case 11, has a long frictional contact length, and has a large effect of generating frictional force.

  (c) The back pressure chamber 91 on the inner periphery of the piston ring 90 is sealed with respect to the oil chambers 27A and 27B of the damper case 11, and the sealing of the back pressure chamber 91 is broken and the internal fluid of the back pressure chamber 91 is broken. However, even if the oil leaks into the oil chambers 27A and 27B of the damper case 11, it does not cause oil leakage to the outside.

  (d) The back pressure applying means 93 communicates the hollow portion 94 provided in the piston rod 12 to the back pressure chamber 91 of the piston ring 90 through the communication hole 95 provided in the piston 25, and the piston rod 12 is hollow. A plunger 96 is provided in the middle of the portion 94, and the same hydraulic oil as that loaded in the oil chambers 27 </ b> A and 27 </ b> B of the damper case 11 is filled from the plunger 96 of the hollow portion 94 to the back pressure chamber 91 side. The hydraulic chambers 97 </ b> A and 97 </ b> B are provided on the counter-back pressure chamber 91 side of the plunger 96. The hydraulic pressure in the hydraulic chambers 97A and 97B, which is increased by the vehicle attitude control device 100 in conjunction with the acceleration / deceleration change of the vehicle, is filled with the hydraulic oil filled in the hollow portion 94 of the piston rod 12 and the communication hole 95 of the piston 25. It exerts on the pressure chamber 91 and pressurizes and pushes the piston ring 90 to generate the frictional force (a). At this time, since the same hydraulic oil loaded in the oil chambers 27A and 27B of the damper case 11 is filled in the back pressure chamber 91 and pressurizes the piston ring 90, the sealing of the back pressure chamber 91 is broken. Even if the hydraulic fluid as the internal fluid of the back pressure chamber 91 leaks into the oil chambers 27A and 27B of the damper case 11, the oil chambers 27A and 27B of the damper case 11 are not soiled.

  (e) The vehicle attitude control device 100 of the above (d) generates a brake fluid pressure in conjunction with the operation of the brake operation unit 101, and the brake master cylinder 102 is a fluid of the back pressure applying means 93. And a brake fluid pressure line 103 connected to the pressure chambers 97A and 97B. When the vehicle is decelerated by a brake operation, the speed of extension of the hydraulic shock absorber constituting the rear cushion unit becomes slow, and the rear lifting can be prevented.

Example 2 (FIGS. 6 to 8)
The second embodiment is different from the first embodiment in that the back pressure applying means 93 of the hydraulic shock absorber 10 is changed to the back pressure applying means 110 and the vehicle attitude control device 100 is changed to the vehicle attitude control device 120.

  As shown in FIGS. 7 and 8, the back pressure applying means 110 communicates the hollow portion 111 provided in the piston rod 12 to the back pressure chamber 91 of the piston ring 90 through the communication hole 112 provided in the piston 25. The piston rod 12 includes a lateral hole 111 </ b> A that communicates the hollow portion 111 with the communication hole 112. The piston 25 includes an annular groove 112A that communicates the communication hole 112 with the back pressure chamber 91 over the entire circumference sandwiched between the insertion grooves of both O-rings 92A and 92B. Note that one end of the hollow portion 111 is closed by a plug 111B.

  Further, the back pressure applying means 110 partitions the middle of the hollow portion 111 of the piston rod 12 with a plunger 113. The plunger 113 can slide liquid-tightly on the inner periphery of the hollow portion 111 through an O-ring provided in the outer peripheral groove. The back pressure applying means 110 is filled with the same (same type) hydraulic oil L as that loaded in the oil chambers 27A and 27B of the damper case 11 from the plunger 113 of the hollow portion 111 of the piston rod 12 to the back pressure chamber 91 side. . In addition, a coil spring 114 is inserted from the plunger 113 of the hollow portion 111 to the anti-back pressure chamber 91 side, and the electric actuator 116 that pressurizes the coil spring 114 is connected to the base side of the piston rod 12, in this embodiment the axle side. Built in the mounting member 15. The electric actuator 116 is composed of a stepping motor (or a solenoid) or the like, and an operator 116A that reciprocates linearly is inserted into the other end opening of the hollow portion 111 of the piston rod 12, and a plunger 115 that is pressed by the operator 116A is inserted. Thus, the coil spring 114 can be pressurized.

  The vehicle attitude control device 120 makes it possible to control the attitude of the vehicle by controlling the pressure applied by the back pressure applying unit 110 to the back pressure chamber 91 according to the acceleration / deceleration state of the vehicle.

  In this embodiment, as shown in FIG. 6, the vehicle attitude control device 120 receives an operation signal of the brake operation unit 121 such as a brake pedal (or brake lever) of the vehicle (the same applies to the detection signal of the brake sensor), The electric actuator 116 is driven by an operation signal from the brake operation unit 121. As a result, in the vehicle attitude control device 120, when the vehicle is decelerated due to a brake operation, the electric actuator 116 is driven, the operation element 116A is protruded to compress the coil spring 114, and the coil spring 114 thus increased. The spring force exerts the hydraulic oil filled in the hollow portion 111 of the piston rod 12 and the communication hole 112 of the piston 25 on the back pressure chamber 91 via the plunger 113, pushes the piston ring 90 open, and opens the inner periphery of the damper case 11. Press on. Regardless of whether or not the oil in the damper case 11 moves due to the expansion / contraction stroke of the hydraulic shock absorber 10, the piston ring 90 is pressed against the inner periphery of the damper case 11 to exert a frictional force. The frictional force of the piston ring 90 becomes a resistance against the expansion / contraction stroke of the hydraulic shock absorber 10, suppresses the expansion of the hydraulic shock absorber 10 constituting the rear cushion unit, slows the expansion speed, and prevents the rear lift.

  Further, as shown in FIG. 6, the vehicle attitude control device 120 receives a detection signal of an acceleration / deceleration sensor 122 that detects acceleration / deceleration (acceleration or deceleration) of the vehicle, and an electric type is detected by the detection signal of the acceleration / deceleration sensor 122. Actuator 116 is driven. Thereby, in the vehicle attitude control device 120, when the vehicle is accelerated or decelerated, the electric actuator 116 is driven, the operation element 116A is projected, the coil spring 114 is compressed, and the spring force of the coil spring 114 is increased thereby. Applies the hydraulic oil filled in the hollow portion 111 of the piston rod 12 and the communication hole 112 of the piston 25 to the back pressure chamber 91 via the plunger 113, pushes the piston ring 90 open and presses it to the inner periphery of the damper case 11. To do. Regardless of whether or not the oil in the damper case 11 moves due to the expansion / contraction stroke of the hydraulic shock absorber 10, the piston ring 90 is pressed against the inner periphery of the damper case 11 to exert a frictional force. The frictional force of the piston ring 90 becomes a resistance against the expansion / contraction stroke of the hydraulic shock absorber 10, suppresses contraction (acceleration) or expansion (during deceleration) of the hydraulic shock absorber 10 constituting the rear cushion unit, and contracts or expands them. To reduce the rear sinking (acceleration) or lifting (deceleration).

  As the acceleration / deceleration sensor 122, a detection result of a throttle opening sensor that controls the fuel supply amount of the vehicle can be used.

Therefore, according to the present embodiment, the following operational effects can be obtained.
(a) The vehicle posture control device 120 controls the pressure applied by the back pressure applying means 110 to the back pressure chamber 91 according to the acceleration / deceleration state of the vehicle. As a result, the pressure in the back pressure chamber 91 applied by the back pressure applying means 110 pressurizes the piston ring 90 and elastically deforms and pushes the piston ring 90 in the diameter increasing direction. A frictional force can be exerted on the piston ring 90 which is about to come into sliding contact with the inner periphery of the damper case before the oil in the damper case starts to move due to the stroke of the hydraulic shock absorber. The frictional force exerted on the piston ring 90 trying to slidably contact the inner periphery of the damper case becomes a resistance against the expansion / contraction stroke of the hydraulic shock absorber, and slows the expansion / contraction speed. When the vehicle is decelerated, if the hydraulic shock absorber constituting the rear cushion unit slows down, the rear lift can be prevented. If the speed of the hydraulic shock absorber constituting the rear cushion unit becomes slow during acceleration of the vehicle, the sinking of the rear can be prevented.

  (b) The piston ring 90 is in frictional contact with the inner periphery of the damper case. The frictional contact length is long and the effect of generating frictional force is large.

  (c) The back pressure chamber 91 on the inner periphery of the piston ring 90 is sealed with respect to the oil chambers 27A and 27B of the damper case, the sealing of the back pressure chamber 91 is broken, and the internal fluid in the back pressure chamber 91 is Even if it leaks into the oil chambers 27A and 27B of the damper case, it does not cause oil leakage to the outside.

  (d) The back pressure applying means 110 communicates the hollow portion 111 provided in the piston rod 12 with the back pressure chamber 91 of the piston ring 90 through the communication hole 112 provided in the piston, and the hollow portion of the piston rod 12 is provided. A plunger 113 is provided in the middle of 111, and the same hydraulic oil as that loaded in the oil chambers 27 </ b> A and 27 </ b> B of the damper case is filled on the back pressure chamber 91 side from the plunger 113 of the hollow portion 111. A coil spring 114 is loaded on the side opposite to the back pressure chamber 91 from 113, and an electric actuator 116 that pressurizes the coil spring 114 is provided on the base side of the piston rod 12. The vehicle attitude control device 120 drives the electric actuator 116 in conjunction with the acceleration / deceleration change of the vehicle, and the spring force of the coil spring 114 that is pressurized by this drives the hollow portion 111 of the piston rod 12 and the communication hole of the piston. The hydraulic oil filled in 112 is applied to the back pressure chamber 91 to pressurize and open the piston ring 90 to generate the frictional force (a) described above. At this time, since the same hydraulic oil loaded in the oil chambers 27A and 27B of the damper case is filled in the back pressure chamber 91 and pressurizes the piston ring 90, the sealing of the back pressure chamber 91 is broken, Even if the hydraulic fluid, which is the internal fluid of the back pressure chamber 91, leaks into the oil chambers 27A and 27B of the damper case, the oil chambers 27A and 27B of the damper case are not soiled.

  (e) The vehicle attitude control device 120 described in (d) above drives the electric actuator 116 by the operation signal from the brake operation unit 121. When the vehicle is decelerated by a brake operation, the speed of extension of the hydraulic shock absorber constituting the rear cushion unit becomes slow, and the rear lifting can be prevented.

  (f) The vehicle attitude control device 120 described in (d) above drives the electric actuator 116 by the detection signal of the acceleration / deceleration sensor 122 that detects the acceleration / deceleration of the vehicle. When the vehicle is accelerated, the speed of the hydraulic shock absorber constituting the rear cushion unit is reduced, and the rear sinking can be prevented.

(Reference Example 1) (FIG. 9)
The reference example 1 shown in FIG. 9 is that, in the hydraulic shock absorber 10 of the second embodiment, the electric actuator 116 of the back pressure applying means 110 is replaced with the adjuster 130 and the vehicle attitude control device 120 is not attached. In the adjuster 130, an adjuster bolt 132 is pivotally supported on a cap 131 provided on the axle-side mounting member 15, and a cam 133 is screwed onto the adjuster bolt 132. An operation portion 115A that protrudes from the hollow portion 111 of the plunger 115 that is inserted into the other end opening of the hollow portion 111 of the piston rod 12 and pressurizes the coil spring 114 is brought into contact with the cam surface of the cam 133. When the adjuster bolt 132 is rotated with a sense of moderation with respect to the click mechanism 134 provided between the cap 131 and the adjuster bolt 132, a screw 133 provided on the axle-side mounting member 15 is screwed to the adjuster bolt 132. The cam surface of the cam 133 pushes the operation portion 115 </ b> A of the plunger 115.

  Therefore, when the plunger 115 is pushed by the adjuster 130 as described above, the coil spring 114 is compressed, and the spring force of the coil spring 114 that is increased by this is compressed via the plunger 113 through the hollow portion 111 and the piston of the piston rod 12. The hydraulic oil filled in the 25 communication holes 112 is applied to the back pressure chamber 91, and the piston ring 90 is pushed open to press the inner circumference of the damper case 11. The adjuster 130 adjusts the amount of advancement of the plunger 115 by adjusting the screw operation amount of the adjuster bolt 132, and thereby adjusts the pressure of the back pressure chamber 91, and the piston ring 90 in the extremely low speed region or high frequency operation region of the piston 25. The damping force of the hydraulic shock absorber 10 can be adjusted by adjusting the frictional force.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention. For example, in the present invention, the damping force generator provided between the piston-side oil chamber of the damper case and the rod-side oil chamber is a communication channel between the piston-side oil chamber and the rod-side oil chamber provided in the piston of the piston rod. It may be a damping force generator provided in the.

  The present invention inserts a piston rod attached to the other of the vehicle body side and the rear wheel support member side into an oil chamber of a damper case attached to one of the vehicle body side and the rear wheel support member side, and uses a piston provided on the piston rod. In a hydraulic shock absorber in which a damper case oil chamber is divided into a piston side oil chamber and a rod side oil chamber, and a damping force generator is provided between the piston case oil chamber and the rod side oil chamber. The piston ring outer periphery is slidably contacted with the inner periphery of the damper case, and the piston ring is made of an elastic material. The back pressure applying means for applying pressure to the back pressure chamber of the piston ring is provided, and the pressure applied to the back pressure chamber by the back pressure applying means is controlled according to the acceleration / deceleration state of the vehicle by the vehicle attitude control device. By a, it was able to control the posture of the vehicle. Thereby, the responsiveness can be improved so that the attitude of the vehicle can be immediately controlled in accordance with the acceleration / deceleration change of the vehicle.

DESCRIPTION OF SYMBOLS 10 Hydraulic buffer 11 Damper case 12 Piston rod 25 Piston 27 Oil chamber 27A Piston side oil chamber 27B Rod side oil chamber 32 Oil reservoir chamber 40 Damping force generator 90 Piston ring 91 Back pressure chamber 93 Back pressure application means 94 Hollow part 95 Communication hole 96 Plunger 97A, 97B Hydraulic chamber 100 Vehicle attitude control device 101 Brake operation unit 102 Brake master cylinder 103 Brake hydraulic pressure line 110 Back pressure applying means 111 Hollow portion 112 Communication hole 113 Plunger 114 Coil spring 116 Electric actuator 120 Vehicle Attitude control device 121 Brake operation unit 122 Acceleration / deceleration sensor

Claims (6)

Inserting a piston rod attached to the other of the vehicle body side and the rear wheel support member side into the oil chamber of the damper case attached to one of the vehicle body side and the rear wheel support member side,
By the piston provided on the piston rod, the oil chamber of the damper case is partitioned into a piston side oil chamber and a rod side oil chamber,
In the hydraulic shock absorber provided with a damping force generator between the piston side oil chamber of the damper case and the rod side oil chamber,
The outer periphery of the piston ring provided on the piston is in sliding contact with the inner periphery of the damper case,
A back pressure chamber sealed against the oil chamber of the damper case is provided on the inner periphery of the piston ring,
The piston ring is made of an elastic material, and provided with a back pressure applying means for applying pressure to the back pressure chamber of the piston ring,
A hydraulic shock absorber, wherein a vehicle posture can be controlled by controlling a pressure applied to a back pressure chamber by a vehicle posture control device in accordance with an acceleration / deceleration state of the vehicle. The back pressure applying means is
The hollow portion provided in the piston rod communicates with the back pressure chamber of the piston ring through the communication hole provided in the piston.
A plunger is provided in the middle of the hollow part of the piston rod, and the back hydraulic pressure chamber is filled with the same hydraulic oil as that loaded in the oil chamber of the damper case from the hollow part plunger. A hydraulic chamber on the side of the chamber,
The vehicle attitude control device is
The hydraulic shock absorber according to claim 1, wherein the hydraulic pressure in the hydraulic pressure chamber is increased in conjunction with a change in acceleration / deceleration of the vehicle.   The vehicle attitude control device includes a brake master cylinder that generates a brake fluid pressure in conjunction with an operation of a brake operation unit, and a brake fluid pressure line that connects the brake master cylinder to a fluid pressure chamber of the back pressure applying unit. The hydraulic shock absorber according to claim 2. The back pressure applying means is
The hollow portion provided in the piston rod communicates with the back pressure chamber of the piston ring through the communication hole provided in the piston.
A plunger is provided in the middle of the hollow part of the piston rod, and the back hydraulic pressure chamber is filled with the same hydraulic oil as that loaded in the oil chamber of the damper case from the hollow part plunger. A spring is loaded on the chamber side, and an electric actuator for pressurizing the spring is provided on the base side of the piston rod.
The vehicle attitude control device is
The hydraulic shock absorber according to claim 1, wherein the electric actuator is driven in conjunction with a change in acceleration / deceleration of the vehicle.   The hydraulic shock absorber according to claim 4, wherein the vehicle attitude control device drives an electric actuator by an operation signal from a brake operation unit.   The hydraulic shock absorber according to claim 4, wherein the vehicle attitude control device drives the electric actuator by a detection signal of an acceleration / deceleration sensor that detects acceleration / deceleration of the vehicle.

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