JP5078574B2 - Damping force adjustment structure of hydraulic shock absorber - Google Patents

Description

  The present invention relates to a damping force adjusting structure for a hydraulic shock absorber.

  As described in Patent Document 1, as a damping force adjusting structure of a hydraulic shock absorber, an oil liquid is accommodated in an oil chamber of a cylinder so that a piston provided at an insertion end of a piston rod inserted into the cylinder can slide on the cylinder. When a damping valve is used to generate a damping force by controlling the flow of oil from one oil chamber to the other, which is pressurized by sliding the piston, pressurize the back side of the damping valve. One of the oil chambers is provided with a back pressure chamber communicating with the orifice, and the back pressure chamber is closed by a free piston biased by a coil spring.

  When the piston speed is in the normal low frequency range, the pressure in the pressurized oil chamber is transmitted to the back pressure chamber without any pressure propagation delay due to the orifice. When the pressure increases, the damping force of the damping valve that receives the pressure in the back pressure chamber increases.

When the vehicle rides on the uneven surface of the road and the piston speed enters the high frequency range, the pressure in the pressurized oil chamber is accompanied by a delay in pressure propagation due to the orifice, does not increase the pressure in the back pressure chamber, and the damping valve easily opens. Decrease the damping force.
Reality 4-43633

  In the damping force adjusting structure of the hydraulic shock absorber described in Patent Document 1, the pushing stroke of the free piston urged by the coil spring is large in the low frequency range of the piston speed, and the pressure in the back pressure chamber increases. Slower, response speed slows down. In addition, the coil spring occupies a large space and it is not easy to set the spring force.

  An object of the present invention is to improve the response and reduce the size of a frequency-dependent hydraulic shock absorber damping force adjustment structure that increases damping force in a low frequency region and decreases damping force in a high frequency region.

According to the first aspect of the present invention, an oil liquid is accommodated in an oil chamber of a cylinder, a piston provided at an insertion end of a piston rod inserted into the cylinder is slidably fitted into the cylinder, and is pressurized by sliding of the piston. In the damping force adjustment structure of a hydraulic shock absorber that generates damping force by controlling the flow of oil from one oil chamber to the other oil chamber using a damping valve, A back pressure chamber communicating with an orifice is provided in the oil chamber, and the back pressure chamber is closed by a partition body made of a leaf spring , and the back pressure chamber slides on the valve housing of the damping valve and the valve housing. The partition is formed by a back-up collar that is provided and urged against the back surface of the damping valve by a spring, and a partition body seated on the support surface of the valve housing, and the leaf spring of the partition body supports the valve housing. It is obtained so as to be freely moved in the plane.

According to a second aspect of the present invention, in the first aspect of the present invention, the partition body further includes a core member provided at the center of the leaf spring, an auxiliary spring is provided on the opposite side of the leaf spring in the axial direction of the core member, and the auxiliary spring is provided. The leaf spring is supported on the valve housing, and the leaf spring is seated on the support surface of the valve housing by the biasing force of the auxiliary spring .

According to a third aspect of the present invention, in the first or second aspect of the present invention, in the piston, a main damping valve is provided in a flow path that communicates the two oil chambers, and the main damping valve is bypassed, A sub-attenuation valve is provided in a bypass passage connecting the chambers, and the back pressure chamber is provided on the back side of the sub-attenuation valve .

(Claim 1)
(a) When the piston speed is in the normal low frequency range, the pressure of the pressurized oil chamber passes through the orifice, enters the back pressure chamber, and then pushes the partition body made of a leaf spring to make a stroke, then the back pressure chamber When the pressure increases, the damping force of the damping valve that receives the pressure in the back pressure chamber increases.

  When the vehicle rides on the road surface and the piston speed enters the high frequency range, the pressure in the pressurized oil chamber does not increase the pressure in the back pressure chamber due to the pressure propagation delay due to the orifice and the stroke of the partition wall, and the damping valve Makes it easier to open and lowers the damping force.

  In the low frequency range of the piston speed, the pushing stroke of the bulkhead urged by the leaf spring is small, the pressure in the back pressure chamber rises quickly, and it can respond without a sense of incongruity even when switching between extension and pressure stroke, and the response speed Is fast. Further, the leaf spring occupies a small space, and the spring force can be easily set by adjusting the number of stacked springs.

  The frequency characteristics of the damping force generated by the hydraulic shock absorber can be easily adjusted by changing the pressure receiving area of the damping valve with respect to the back pressure chamber, the flow path area of the orifice, or the spring constant of the leaf spring of the partition wall.

(b) Since the leaf spring of the partition wall is free to move on the support surface of the valve housing, the spring constant of the leaf spring can be easily reduced. In the low frequency range of the piston speed, the pressure rise in the back pressure chamber can be increased and the response speed can be increased.

(Claim 2 )
(c) The partition body is provided with a core material in the center of the leaf spring, an auxiliary spring is provided on the opposite side of the leaf spring in the axial direction of the core material, the auxiliary spring is supported on the valve housing, and the biasing force of the auxiliary spring The leaf spring is seated on the support surface of the valve housing. The leaf spring of the partition wall can be stably seated on the support surface of the valve housing by the biasing force of the auxiliary spring.

(Claim 3 )
(d) A main damping valve and a sub damping valve are provided, and a back pressure chamber is provided on the back side of the sub damping valve. By making the bending rigidity of the main damping valve larger than the bending rigidity of the sub damping valve, a high damping force can be obtained by the main damping valve at normal times when the piston speed is in the low frequency range. When the piston speed enters the high frequency range, the sub damping valve can be easily opened and the damping force can be lowered by the above-described (a), and the bull feeling of slight vibration can be eliminated. That is, in the normal low frequency range, the main damping valve provides stable damping force in a wide range of piston speeds from low to high, ensuring operability, and high frequency micro vibrations are absorbed by opening the sub damping valve. , Can ensure ride comfort.

  Furthermore, even in the normal low frequency range, by setting the pressure receiving area for the back pressure chamber of the sub damping valve to be small, the sub damping valve opens when the damping force of the main damping valve increases, and the upper limit of the damping force Can be set (high-speed blow).

  Even in the normal low frequency range, by setting the pressure receiving area for the back pressure chamber of the sub damping valve to be small, the damping force is generated by the sub damping valve, and when the damping force of the sub damping valve increases, the main damping It is also possible to set the upper limit of the damping force (fast blow) by opening the valve.

  FIG. 1 is a schematic cross-sectional view showing a hydraulic shock absorber, FIG. 2 is a cross-sectional view showing damping force adjusting means, FIG. 3 shows the flow of oil in the hydraulic shock absorber, and FIG. FIG. 4B is a schematic diagram showing a high-frequency region in the extension stroke, FIG. 4C is a schematic diagram showing a compression stroke, FIG. 4 is a plan view showing a slit valve, and FIG. 5 is a plan view showing a spring. .

  As shown in FIG. 1, the damping force adjusting hydraulic shock absorber 10 is a double cylinder type composed of a double pipe in which a cylinder 12 is built in a damper tube 11, and a piston rod 13 is inserted into a cylinder 12 containing oil. The axle tube side mounting portion is provided at the lower portion of the damper tube 11 and the vehicle body side mounting portion 14 is provided at the upper portion of the piston rod 13 to constitute a vehicle suspension device.

  The hydraulic shock absorber 10 has a suspension spring 16 interposed between a lower spring seat 15 on the outer periphery of the damper tube 11 and an upper spring seat (not shown) provided on the vehicle body side mounting portion 14 at the upper end portion of the piston rod 13. To do.

  The hydraulic shock absorber 10 clamps a rod guide 17, a bush 18, and an oil seal 19 for the piston rod 13 inserted into the cylinder 12 between the upper end crimped portion 11 </ b> A of the damper tube 11 and the upper end portion of the cylinder 12. It is fixed.

  The damping force adjusting hydraulic shock absorber 10 includes a piston valve device 20 and a bottom valve device 40. The piston valve device 20 and the bottom valve device 40 generate a damping force by controlling the flow of oil and liquid caused by the piston 24 (described later) provided at the insertion end of the piston rod 13 into the cylinder 12 sliding on the cylinder 12. The expansion and contraction vibration of the piston rod 13 accompanying the absorption of the impact force by the suspension spring 16 is suppressed by the damping force generated by them.

(Piston valve device 20)
As shown in FIG. 2, the piston valve device 20 has a screw portion 21 on the outer periphery of the insertion end of the piston rod 13 into the cylinder 12, and a valve stopper 23, a piston 24, and a valve stopper 25 are inserted on the outer periphery of the screw portion 21. These are clamped and fixed between the base end step portion of the screw portion 21 by a valve housing 61 for the sub-extension-side damping valve 60, which is screwed to the screw portion 21.

  The piston 24 is slidably inserted into the cylinder 12, and is provided with an expansion side flow path 31 and a pressure side flow path 32, and an annular center of a disk valve-shaped main expansion side damping valve 33 between the piston 24 and the valve stopper 25. And the annular central portion of the disc-valve compression side damping valve 34 is clamped between the piston 24 and the valve stopper 23. That is, the piston valve device 20 divides the inside of the cylinder 12 into a rod side chamber 12A and a piston side chamber 12B by a piston 24. The rod side chamber 12A and the piston side chamber 12B are provided with an extension side channel 31 provided in the piston 24 and the extension side channel. The main extension side damping valve 33 that opens and closes 31, the pressure side flow path 32, and the pressure side damping valve 34 that opens and closes the pressure side flow path 32 communicate with each other.

  Therefore, at the time of extension, the oil in the rod side chamber 12A passes through the extension side flow path 31 of the piston 24, bends and opens the main extension side damping valve 33, is guided to the piston side chamber 12B, and generates an extension side damping force. . At the time of compression, the oil in the piston side chamber 12B passes through the pressure side flow path 32 of the piston 24, bends and deforms the pressure side damping valve 34, is guided to the rod side chamber 12A, and generates a pressure side damping force.

(Bottom valve device 40)
In the hydraulic shock absorber 10, a gap between the damper tube 11 and the cylinder 12 is defined as a reservoir chamber 12C, and the interior of the reservoir chamber 12C is partitioned into an oil chamber and a gas chamber. The bottom valve device 40 includes a bottom piece 41 that partitions the piston side chamber 12B and the reservoir chamber 12C inside the cylinder 12 between the lower end portion of the cylinder 12 and the bottom portion of the damper tube 11, and the bottom portion of the damper tube 11. The space between the bottom piece 41 and the bottom piece 41 can be communicated with the reservoir chamber 12C through a flow path provided in the bottom piece 41.

  The bottom valve device 40 includes a disk valve 42 and a check valve 43 as bottom valves for opening and closing a pressure side channel 41A and an extension side channel (not shown) provided in the bottom piece 41, respectively.

  At the time of extension, the oil corresponding to the retraction volume of the piston rod 13 retreating from the cylinder 12 pushes the check valve 43 open, and enters the piston side chamber 12B from the reservoir chamber 12C via the expansion side flow path (not shown) of the bottom piece 41. To be replenished. During compression, the oil corresponding to the volume of the piston rod 13 entering the cylinder 12 is opened from the piston side chamber 12B through the pressure side flow path 41A of the bottom piece 41 by bending and deforming the disk valve 42 and pushed into the reservoir chamber 12C. Get the compression side damping force.

  In the hydraulic shock absorber 10, the piston rod 13 extends around the piston rod 13 positioned in the rod side chamber 12A of the cylinder 12 and on the rebound seat 46 fixed to the piston 24 side (lower side). A rebound rubber 47 that is compressed and deformed at the time of cutting (the most extended state of the hydraulic shock absorber 10) is provided.

  However, the hydraulic shock absorber 10 includes an extension side damping force adjusting device 50 for adjusting the damping force of the piston valve device 20, in this embodiment, the extension side damping force as follows.

  As shown in FIG. 2, the extension side damping force adjusting device 50 is provided with a sub extension side damping valve 60 in a bypass passage 51 that bypasses the main extension side damping valve 33 and communicates the rod side chamber 12A and the piston side chamber 12B. A disk valve-like sub extension side is provided between the valve stopper 25 of the main extension side damping valve 33 inserted into the screw part 21 of the piston rod 13 and the valve housing 61 screwed to the screw part 21 of the piston rod 13. The annular central portion of the damping valve 60 is clamped. That is, the extension side damping force adjusting device 50 opens one end of the bypass passage 51 into the rod side chamber 12A and opens the other end of the bypass passage 51 into the sub flow path 25A provided in the valve stopper 25, thereby sub-extension attenuation. The sub channel 25A is opened and closed with respect to the piston side chamber 12B by the valve 60.

  The extension side damping force adjusting device 50 is connected to the back side of the sub extension side damping valve 60 on the back side thereof through the orifice 62A of the slit valve 62 to the rod side chamber 12A (one oil chamber pressurized when extended). 63 is provided, and the back pressure chamber 63 is closed by a partition body 70 formed of a leaf spring 71. The slit valve 62 is attached to the back surface of the sub extension side damping valve 60, and an annular central portion is sandwiched between the valve stopper 25 of the main extension side damping valve 33 and the valve housing 61. As shown in FIG. 4, the slit valve 62 is provided with a cross-shaped slit on the inner periphery of the annular central portion, and each slit serves as an orifice 62A.

  The extension-side damping force adjusting device 50 includes a combined body of a main body 61A in which the valve housing 61 is screwed to the screw portion 21 of the piston rod 13 and a cylindrical body 61B that is fitted to the outer periphery of the large-diameter portion of the main body 61A. Shall be. The valve housing 61 engages a cylindrical body 61B fitted from one side in the axial direction of the main body 61A with an outer peripheral corner portion on one end side (upper end side) of the large diameter portion of the main body 61A. An annular spacer 64 and a stopper 65, which are sequentially stacked on the other end surface (lower end surface) in the axial direction, are held together by a crimping portion at the tip of the cylindrical body 61B and integrally provided. The valve housing 61 is provided with a plurality of communication holes 61C around a small diameter portion (a step surface between the small diameter portion and the large diameter portion) provided around the screw portion 21 of the piston rod 13 of the main body 61A. The back pressure chamber 63 can be continuously provided on both sides.

  The back pressure chamber 63 includes a valve housing 61 of the sub-extension-side damping valve 60, a backup collar 67 that is slidably provided on the valve housing 61 and is biased to the back surface of the sub-extension-side damping valve 60 by a spring 66, A partition wall 70 is formed on the support surface 68 of the valve housing 61 (in this embodiment, the outer peripheral side upper surface 68 of the stopper 65). The backup collar 67 slides up and down in a liquid-tight manner on the sealing material 67A loaded in the annular groove on the inner periphery of the cylindrical body 61B of the valve housing 61, and the upper end surface of the backup collar 67 is on the back surface of the sub-extension-side damping valve 60. Collide. As shown in FIG. 5, the spring 66 includes a cross-shaped protruding portion 66 </ b> A on the outer periphery of the annular central portion, and the inner periphery of the annular central portion is inserted into the outer periphery of the small diameter portion of the main body 61 </ b> A of the valve housing 61. And the lower end surface of the backup collar 67 is supported on the tip portion of the overhanging portion 66A.

  The partition body 70 is provided with a core 73 at the center of a disc-shaped plate spring 71, an auxiliary spring 72 is provided on the opposite side of the plate spring 71 in the axial direction of the core 73, and the auxiliary spring 72 is connected to the valve housing 61. The plate spring 71 is seated on the support surface 68 of the stopper 65 by the lower end support surface 69 of the large diameter portion of the main body 61 </ b> A and the biasing force of the auxiliary spring 72. In this embodiment, the auxiliary spring 72 is also made of a disk-shaped plate spring, and the core member 73 has small diameter portions 73B and 73C projecting on both sides in the axial direction of the bulging portion 73A, and the small diameter portion 73B. In the state in which the center hole of the leaf spring 71 is loaded and the center hole of the auxiliary spring 72 is loaded in the small diameter portion 73C, the outer edge side end surface of the leaf spring 71 is placed on the support surface 68 of the stopper 65 and is seated. The outer edge side end surface of 72 is placed on and supported by the support surface 69 of the valve housing 61. The leaf spring 71 of the partition wall 70 is not fixedly held on the support surface 68 of the stopper 65, but is freely slidable along the surface of the support surface 68, and the spring constant of the leaf spring 71 is set low. . The auxiliary spring 72 of the partition wall 70 is also free to slide along the support surface 69 of the valve housing 61.

  In the partition body 70, in the extension side stroke, the pressure of the rod side chamber 12 </ b> A to be pressurized receives the pressure of the back pressure chamber 63 applied from the bypass passage 51 via the orifice 62 </ b> A, the leaf spring 71 bends, and the auxiliary spring 72. Is separated from the support surface 69 of the valve housing 61, and the pressure in the back pressure chamber 63 reaches the intermediate chamber 74 between the leaf spring 71 and the auxiliary spring 72. In the extension side stroke, the leaf spring 71 of the partition wall body 70 abuts against the abutment surface 65B of the stopper 65, and the deflection of the leaf spring 71 is restricted. In the reverse pressure side stroke, the pressure of the pressurized piston side chamber 12B extends from the communication hole 65A provided in the central surface of the stopper 65 to the leaf spring 71, the auxiliary spring 72 is bent, and the leaf spring 71 is the support surface of the stopper 65. The pressure in the piston side chamber 12 </ b> B extends to the intermediate chamber 74. In the compression side stroke, the core member 73 of the partition wall body 70 abuts against the end face of the piston rod 13 and restricts the bending of the auxiliary spring 72. The partition body 70 repeats the above-described extension side stroke and pressure side stroke, causes a delay in the pressure propagation in the rod side chamber 12A in the extension side stroke, and causes a delay in the pressure propagation in the piston side chamber 12B in the compression side stroke. The spring constants of the leaf spring 71 and the auxiliary spring 72 can be set independently of each other, and the pressure propagation delay from the rod side chamber 12A to the back pressure chamber 63 is generated by reducing the number of laminated leaf springs 71 and setting the extension side weak. The pressure side of the piston side chamber 12B is slightly increased by increasing the number of laminated auxiliary springs 72 to make the pressure side strong, and the response speed of the damping force of the piston valve device 20 and the extension side damping force adjusting device 50 can be adjusted. .

  The extension side damping force adjusting device 50 regulates the stroke of the partition wall 70 by the stopper 65 and can make the stroke a minute stroke of about 1 to 2 mm, improving the responsiveness at the time of switching between the extension and the compression stroke. it can. The communication hole 65A provided in the stopper 65 may be an orifice. By making the flow path area of the orifice 65A larger than the orifice 62A at the inlet of the back pressure chamber 63, the opening / closing timing of the compression side damping valve 34 is frequency-dependent in the compression side stroke without affecting the frequency dependency in the expansion side stroke. Can be adjusted.

Accordingly, the hydraulic shock absorber 10 includes the extension side damping force adjusting device 50 and operates as follows.
(1) When the piston speed of the hydraulic shock absorber 10 is in a normal low frequency region during the extension stroke, the pressure in the pressurized rod side chamber 12A is propagated through the orifice 62A as shown in FIG. When the pressure in the back pressure chamber 63 rises after the pressure is transferred to the back pressure chamber 63 without delay and the partition body 70 made of the leaf spring 71 is pushed and stroked, the sub pressure receiving the pressure in the back pressure chamber 63 is received. The main extension side damping valve 33 is opened without generating the extension side damping valve 60 to generate a damping force. The main extension side damping valve 33 has a higher bending rigidity than the sub extension side damping valve 60 so as to improve the maneuverability during normal running, and generates a normally required damping force.

  (2) When the vehicle rides on the road surface unevenness and the piston speed enters the high frequency range in the extension side stroke, the pressure in the pressurized rod side chamber 12A is delayed by the pressure propagation by the orifice 62A as shown in FIG. Accordingly, the pressure in the back pressure chamber 63 is not increased, and the sub-extension-side damping valve 60 is easily opened to reduce the damping force.

  (3) In the pressure side stroke, as shown in FIG. 3C, the pressure side damping valve 34 is opened to generate a damping force.

According to the present embodiment, the following operational effects can be obtained.
(a) In the low frequency range of the piston speed, the push-in stroke of the partition body 70 biased by the leaf spring 71 is small, the pressure in the back pressure chamber 63 rises quickly, and there is a sense of incongruity even when the extension / pressure stroke is switched. It can respond without any problems and the response speed is fast. The leaf spring 71 occupies a small space, and the spring force can be easily set by adjusting the number of stacked springs.

  The frequency characteristics of the damping force generated by the hydraulic shock absorber 10 by changing the pressure receiving area of the sub extension side damping valve 60 with respect to the back pressure chamber 63, the flow path area of the orifice 62A, or the spring constant of the leaf spring 71 of the partition wall 70 is obtained. Easy to adjust.

  (b) Since the leaf spring 71 of the partition wall 70 is free to move on the support surface 68 of the valve housing 61, the spring constant of the leaf spring 71 can be easily reduced. In the low frequency region of the piston speed, the pressure increase in the back pressure chamber 63 can be accelerated and the response speed can be increased.

  (c) The partition body 70 is provided with a core 73 at the center of the leaf spring 71, an auxiliary spring 72 is provided on the opposite side of the leaf spring 71 in the axial direction of the core 73, and the auxiliary spring 72 is supported on the valve housing 61. The leaf spring 71 is seated on the support surface 68 of the valve housing 61 by the biasing force of the auxiliary spring 72. The leaf spring 71 of the partition wall 70 can be stably seated on the support surface 68 of the valve housing 61 by the biasing force of the auxiliary spring 72.

  (d) The main extension side damping valve 33 and the sub extension side damping valve 60 are provided, and the back pressure chamber 63 is provided on the back side of the sub extension side damping valve 60. By making the deflection rigidity of the main extension side damping valve 33 larger than the deflection rigidity of the sub extension side damping valve 60, a high damping force can be obtained by the main extension side damping valve 33 in the normal time when the piston speed is in a low frequency range. it can. When the piston speed enters the high frequency range, the sub-extension-side damping valve 60 can be easily opened and the damping force can be lowered by the above-described (a), and the feeling of slight vibration can be eliminated. That is, in the normal low frequency range, the main expansion side damping valve 33 provides a stable damping force in a wide range of piston speeds from low to high speed to ensure operability, and high-frequency micro vibrations are generated by the sub expansion side damping valve 60. It absorbs by opening and can secure riding comfort.

  Furthermore, even in a normal low frequency range, by setting the pressure receiving area of the sub extension side damping valve 60 to the back pressure chamber 63 to be small, when the damping force of the main extension side damping valve 33 is increased, the sub extension side damping valve is increased. 60 can be opened, and the upper limit of the damping force can be set (fast blow).

  Even in a normal low frequency range, by setting the pressure receiving area of the sub extension side damping valve 60 to the back pressure chamber 63 to be small, a damping force is generated by the sub extension side damping valve 60, and When the damping force increases, the main extension side damping valve 33 can be opened to set an upper limit of the damping force (high-speed blowing).

  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. In the hydraulic shock absorber 10 described above, a sub pressure side damping valve may be provided in a bypass path that bypasses the pressure side damping valve 34, and the back pressure chamber of the present invention may be provided on the back side of the sub pressure side damping valve.

  Further, in the hydraulic shock absorber 10 described above, the sub expansion side damping valve 60 is not provided, the back pressure chamber of the present invention is provided on the back side of the extension side damping valve 33, and / or the back side of the compression side damping valve 34 is installed on the back side. You may provide the back pressure chamber of invention.

FIG. 1 is a schematic cross-sectional view showing a hydraulic shock absorber. FIG. 2 is a cross-sectional view showing the damping force adjusting means. 3A and 3B show the flow of oil in the hydraulic shock absorber, FIG. 3A is a schematic diagram showing a low frequency region in the extension side stroke, FIG. 3B is a schematic diagram showing a high frequency region in the extension side stroke, and FIG. It is a schematic diagram which shows a process. FIG. 4 is a plan view showing the slit valve. FIG. 5 is a plan view showing the spring.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Hydraulic buffer 12 Cylinder 12A Rod side chamber 12B Piston side chamber 13 Piston rod 24 Piston 33 Main extension side damping valve 34 Pressure side damping valve 50 Extension side damping force adjustment device 51 Bypass path 60 Sub extension side damping valve 61 Valve housing 62 Slit valve 62A Orifice 63 Back pressure chamber 66 Spring 67 Backup collar 68 Support surface 70 Partition body 71 Leaf spring 72 Auxiliary spring 73 Core material

Claims (3)

Oil is stored in the oil chamber of the cylinder, the piston provided at the insertion end of the piston rod inserted into the cylinder is slidably fitted into the cylinder, and the pressure is increased from one oil chamber to the other. In the damping force adjustment structure of the hydraulic shock absorber that generates damping force by controlling the flow of oil liquid into the oil chamber of the
On the back side of the damping valve, a back pressure chamber communicating with one pressurized oil chamber via an orifice is provided, and the back pressure chamber is closed by a partition body made of a leaf spring ,
The back pressure chamber includes a valve housing of a damping valve, a backup collar that is slidably provided on the valve housing and is urged against the back surface of the damping valve by a spring, and a partition body that is seated on the support surface of the valve housing. Compartments formed,
A damping force adjusting structure for a hydraulic shock absorber, wherein a leaf spring of a partition wall is freely movable on a support surface of a valve housing . The partition body is provided with a core material at the center of the leaf spring, an auxiliary spring is provided on the opposite side of the leaf spring in the axial direction of the core material, the auxiliary spring is supported on the valve housing, and the leaf spring is urged by the biasing force of the auxiliary spring. The damping force adjusting structure for a hydraulic shock absorber according to claim 1 , wherein the hydraulic shock absorber is seated on a support surface of the valve housing. In the piston, a main damping valve is provided in a flow path communicating both the oil chambers,
By providing a sub-attenuation valve in the bypass path that bypasses the main damping valve and connects both oil chambers,
3. The damping force adjusting structure for a hydraulic shock absorber according to claim 1, wherein the back pressure chamber is provided on the back side of the sub damping valve.

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