JP6438339B2 - Hydraulic shock absorber - Google Patents

Description

  The present invention relates to a hydraulic shock absorber for a vehicle suitable for use in, for example, a front fork of a motorcycle.

  As a conventional hydraulic shock absorber, there is a hydraulic shock absorber described in Patent Document 1. This hydraulic shock absorber allows the inner tube to slide inside the outer tube through bushes fixed to the inner peripheral opening of the outer tube on the vehicle body side and the outer peripheral tip of the inner tube on the wheel side. An annular oil chamber surrounded by the inner periphery of the outer tube, the outer periphery of the inner tube, and the two bushes is defined. A partition wall member is provided on the inner periphery of the inner tube, an oil chamber is defined in the lower portion, and an oil reservoir chamber including an air chamber is defined in the upper portion.

  In this hydraulic shock absorber, a piston rod attached to the outer tube is removably inserted into the inner tube via the partition member, and an inner periphery of the inner tube is inserted into a tip portion of the piston rod inserted into the inner tube. A piston that is in sliding contact with is fixed. The piston divides the oil chamber into a piston rod side oil chamber in which the piston rod is accommodated and a piston side oil chamber in which the piston rod is not accommodated. The annular oil chamber communicates with the piston rod side oil chamber or the piston side oil chamber through an oil hole provided in the inner tube.

  This hydraulic shock absorber eliminates the cylinder in the inner tube, and the piston is in sliding contact with the inner periphery of the inner tube, greatly increasing the pressure receiving area of the piston, reducing the damper pressure (differential pressure), and the response of damping force Improves.

Patent No. 4055843 (issued March 5, 2008)

  However, the conventional technology as described above has good running stability in a region where the stroke speed of the hydraulic shock absorber is relatively slow, such as when braking or turning over a motorcycle, but the damper pressure (differential pressure) As a result, the riding comfort is hardened particularly in a region where the stroke speed of the hydraulic shock absorber is relatively high, such as when traveling at high speed on an uneven road surface. That is, there is room for improvement in impact absorbability due to road surface unevenness. When this is viewed from the hydraulic shock absorber, there is room for improvement in impact absorbability in a region where the stroke speed is relatively high.

  An object of the present invention is to provide a hydraulic shock absorber that can achieve both running stability in a region where the stroke speed is low and shock absorption in a region where the stroke speed is high.

  In order to solve the above problems, a hydraulic shock absorber according to the present invention includes a first tube, a second tube that slides inside the first tube and is filled with oil, and an inside of the second tube. A suspension spring arranged, a piston rod fixed in an end of the first tube in the first direction in the axial direction, and removably inserted into the second tube; and the piston rod opposite to the first direction A first piston that is fixed to the second direction side and generates a damping force while sliding on the inner periphery of the second tube; a gas chamber provided on the second direction side of the first piston; And a gas chamber rod provided on the second direction side of the piston rod and inserted into the gas chamber so as to freely enter and exit.

  In this specification, the “gas spring” means a member that uses a reaction force of a gas sealed in a container as a spring.

  According to this feature, hydraulic oil corresponding to the volume of the gas chamber rod that enters the gas chamber in the pressure side stroke is supplied from the piston rod side oil chamber to the piston side oil chamber via the damping force adjusting device of the first piston. The In the region where the stroke speed of the compression side stroke is slow, the hydraulic oil is supplied from the oil reservoir chamber to the piston rod side oil chamber via the oil amount adjusting device in time, so the damping force loop by the damping force adjusting device of the first piston is disturbed. There is no stability. On the other hand, in the region where the stroke speed is high, the supply of hydraulic oil from the oil reservoir chamber to the piston rod side oil chamber through the oil amount adjusting device is not in time, and the pressure is changed by the piston rod side oil chamber converting to negative pressure. The balance is disturbed and the damping force loop is dented. The dampening of the damping force loop can delay the rise of damping force in the region where the stroke speed is high, and can improve the shock absorption due to the unevenness of the road surface, so the running stability in the region where the stroke speed is slow And shock absorption in a region where the stroke speed is high.

  In the hydraulic shock absorber according to the present invention, an annular oil chamber is defined between the inner periphery of the first tube and the outer periphery of the second tube, and the first cross-sectional area of the annular oil chamber is the piston rod. It is preferable that it be formed larger than the second cross-sectional area.

  According to the above configuration, the first cross-sectional area S1 of the annular oil chamber is formed larger than the second cross-sectional area S2 of the piston rod (S2 <S1), and the volume increase (ΔS1) of the annular oil chamber in the compression side stroke is Since it is larger than the piston rod entry volume (ΔS2), the piston rod entry volume (ΔS2) is absorbed by the volume increase (ΔS1) of the annular oil chamber. Further, since the shortage of (ΔS1−ΔS2) is supplied from the oil reservoir chamber to the piston rod side oil chamber via the oil amount adjusting device, it is possible to prevent air from entering the piston rod side oil chamber from the air chamber. Can do.

  The hydraulic shock absorber according to the present invention preferably further includes a second piston that is fixed to an end of the gas chamber rod on the second direction side and moves inside the gas chamber.

  According to the said structure, a 2nd piston is guided to the inner periphery of a gas chamber, and operation | movement of a gas chamber rod is stabilized.

  In the hydraulic shock absorber according to the present invention, it is preferable that a flange portion for fixing the gas chamber to the second tube is provided, and the suspension spring is provided between the first piston and the flange portion.

  According to the above configuration, the suspension spring can be used for fixing the gas chamber, and the configuration of the hydraulic shock absorber becomes simple and compact.

  The hydraulic shock absorber according to the present invention has an effect that it is possible to achieve both running stability in a region where the stroke speed is low and impact absorption in a region where the stroke speed is high.

(A) is a front view of the hydraulic shock absorber according to the embodiment, and (b) is a sectional view thereof. It is sectional drawing which expands and shows the structure of the gas spring and gas spring rod which were provided in the said hydraulic shock absorber. It is sectional drawing which expands and shows the peripheral part of the partition member and piston which were provided in the said hydraulic shock absorber, and is sectional drawing which expands and shows the A section of FIG.1 (b). (A) is a graph which shows the damping force loop of the conventional hydraulic shock absorber, (b) is a graph which shows the damping force loop of the hydraulic shock absorber which concerns on embodiment.

  Hereinafter, embodiments of the present invention will be described in detail.

(Configuration of hydraulic shock absorber 10 according to the embodiment)
Fig.1 (a) is a front view of the hydraulic shock absorber 10 which concerns on embodiment, (b) is the sectional drawing. The hydraulic shock absorber 10 includes an outer tube 11 (first tube) and an inner tube 12 (second tube). The inner tube 12 is connected to the inside of the outer tube 11 via a first bush 11A fixed to the inner periphery of the lower end opening of the outer tube 11 and a second bush 12A fixed to the outer periphery of the upper end opening of the inner tube 12. It is slidably inserted into. An oil seal 11B and a dust seal 11C are fixed to the inner periphery of the lower end opening below the first bush 11A. A first cap 13 is screwed into the upper end opening of the outer tube 11 in a liquid-tight manner. A bottom bracket 15 is screwed in a liquid-tight manner at the lower end opening of the inner tube 12, and a wheel side mounting portion 16 is provided on the bottom bracket 15.

  In the hydraulic shock absorber 10, an annular oil chamber 17 surrounded by the inner periphery of the outer tube 11, the outer periphery of the inner tube 12, and the two first bushes 11A and the second bushes 12A is formed.

  In the hydraulic shock absorber 10, a partition wall member 19 is provided on the inner periphery of the upper end side of the inner tube 12 in a liquid-tight manner via an O-ring (not shown). The rod guide portion 19 </ b> A of the partition wall member 19 partitions the lower oil chamber 21 and the upper oil reservoir chamber 22. The oil reservoir chamber 22 includes an oil chamber 22A in the lower region and an air chamber 22B in the upper region.

  In the hydraulic shock absorber 10, the piston rod 23 attached to the outer tube 11 is slidably inserted into the rod guide portion 19 </ b> A of the partition wall member 19. Specifically, a spring load adjusting sleeve 24 is screwed in a liquid-tight manner at the center of the first cap 13, and a hollow piston rod 23 is screwed into a lower end portion of the spring load adjusting sleeve 24 inserted into the oil reservoir chamber 22. This is fixed with a lock nut 25. Thus, the piston rod 23 is inserted into the inner tube 12 through the partition wall member 19 so as to freely enter and exit.

  In the hydraulic shock absorber 10, the first piston 26 slidably contacting the inner periphery of the inner tube 12 is fixed to the tip of the piston rod 23 inserted into the inner tube 12 from the rod guide portion 19 </ b> A of the partition wall member 19. The first piston 26 partitions the oil chamber 21 into a piston rod side oil chamber 21A in which the piston rod 23 is accommodated and a piston side oil chamber 21B in which the piston rod 23 is not accommodated. The first piston 26 is fixed by a nut 27.

  In the hydraulic shock absorber 10, the annular oil chamber 17 is communicated with the piston rod side oil chamber 21 </ b> A through an oil hole 28 provided in the inner tube 12. The annular oil chamber 17 may be communicated with the piston-side oil chamber 21 </ b> B through an oil hole 28 provided in the inner tube 12.

  A connecting member 74 is provided on the lower end surface of the first piston 26 facing the piston-side oil chamber 21B. A gas spring rod 72 (gas chamber rod) projects downward from the connecting member 74. A first spring collar 31 is provided on the lower end surface of the connecting member 74 facing the piston-side oil chamber 21B.

  FIG. 2 is an enlarged cross-sectional view showing the configuration of the gas spring 71 (gas chamber) and the gas spring rod 72 provided in the hydraulic shock absorber 10.

  A gas spring 71 is provided at the bottom of the piston side oil chamber 21 </ b> B of the inner tube 12. The gas spring rod 72 is slidably inserted into the gas spring 71 via a first seal member 75 and a rod guide 76 disposed at the upper end of the gas spring 71. A second piston 73 slidably contacting the inner periphery of the gas spring 71 is fixed to the tip of the gas spring rod 72. A second cap 78 is provided on the lower end of the gas spring 71 via a second seal member 77.

  The gas spring 71 has a flange 71 </ b> A at one end on the opposite side of the first piston 26. A suspension spring 33 is interposed between the first spring collar 31 and the flange portion 71A. The hydraulic shock absorber 10 moves the piston rod 23, the first piston 26, and the connecting member 74 up and down by screwing the above-described spring load adjusting sleeve 24, and adjusts the spring load of the suspension spring 33 by this up and down movement. To do. The hydraulic shock absorber 10 absorbs the impact force received from the road surface during traveling of the vehicle by the expansion and contraction vibration of the suspension spring 33.

  FIG. 3 is an enlarged cross-sectional view of the partition member 19 provided in the hydraulic shock absorber 10 and the peripheral portion of the first piston 26 (A portion surrounded by a broken line in FIG. 1B).

  The hydraulic shock absorber 10 includes a damping force adjusting device 40 in the first piston 26. The damping force adjusting device 40 includes a compression side channel 41 and an extension side channel 42. The pressure side channel 41 is opened and closed by a pressure side disk valve 41A backed up by the first valve stopper 41B. The extension side flow path 42 is opened and closed by an extension side disk valve 42A backed up by the second valve stopper 42B.

  The damping force adjusting device 40 includes an adjusting rod 43 that is screwed in a liquid-tight manner at the center of the spring load adjusting sleeve 24, and a needle valve 44 that is fixed to the adjusting rod 43 and inserted into the hollow portion of the piston rod 23. Have. The opening degree of the bypass passage 45 provided in the piston rod 23 is adjusted by the vertical movement of the needle valve 44. The bypass passage 45 bypasses the first piston 26 and connects the piston rod side oil chamber 21A and the piston side oil chamber 21B.

  In the compression side stroke, the damping force adjusting device 40 generates a compression side damping force by the passage resistance of the bypass passage 45 whose opening degree is adjusted by the needle valve 44 in the low speed region, and the deformation deformation of the compression side disk valve 41A in the medium to high speed region. Generates a compression damping force. Further, in the extension side stroke, an extension side damping force is generated by the passage resistance of the bypass passage 45 whose opening degree is adjusted by the needle valve 44 in the low speed range, and in the middle and high speed range, the extension side disc valve 42A is extended by bending deformation. Generates side damping force. The above-described expansion and contraction vibration of the suspension spring 33 is suppressed by the compression side damping force and the extension side damping force.

  A stopper rubber 13A is fixed to the lower end surface of the first cap 13 so that the upper end portion of the partition wall member 19 provided on the inner tube 12 abuts at the maximum compression stroke. The maximum compression stroke is regulated by the stopper rubber 13A. The

  In the hydraulic shock absorber 10, a spring seat 48 that is caulked and fixed to the lower end surface facing the piston rod side oil chamber 21 </ b> A of the partition wall member 19 on the upper end side of the inner tube 12, and a first provided on the upper end surface side of the first piston 26. A rebound spring 50 is disposed between the two spring collars 49. When the hydraulic shock absorber 10 is fully extended, the partition member 19 pressurizes the rebound spring 50, whereby the maximum extension stroke is regulated.

  In the hydraulic shock absorber 10, the first cross-sectional area S <b> 1 of the annular oil chamber 17 formed by the annular gap between the outer tube 11 and the inner tube 12 is changed to the second cross-sectional area S <b> 2 of the piston rod 23 (the outer periphery of the piston rod 23. (S2 <S1).

  The rod guide portion 19A of the partition wall member 19 is allowed to flow oil from the oil reservoir chamber 22 to the piston rod side oil chamber 21A in the pressure side stroke, and from the piston rod side oil chamber 21A to the oil reservoir chamber 22 in the extension side stroke. A check valve 60 is provided to block oil flow. The rod guide portion 19 </ b> A is further formed with a micro flow channel (micro flow channel) that communicates the piston rod side oil chamber 21 </ b> A and the oil reservoir chamber 22. The check valve 60 and the minute flow path operate between the oil reservoir 22 and the oil chamber 21 in order to adjust the amount of oil in the oil chamber 21 as the volume of the oil chamber 21 changes due to the piston rod 23 entering and leaving. An oil amount adjusting device that forms an oil flow is configured.

  The hydraulic shock absorber 10 slides inside the outer tube 11, the outer tube 11, the oil filled inner tube 12, a suspension spring 33 disposed inside the inner tube 12, and the axial direction of the outer tube 11. The end of the first direction is fixed, the piston rod 23 is inserted into the inner tube 12 so as to freely enter and exit, the second direction side of the piston rod 23 opposite to the first direction is fixed, and the inner tube 12 A first piston 26 that generates a damping force while sliding on the inner periphery, a gas spring 71 provided on the second direction side of the first piston 26, and a gas spring 71 provided on the second direction side of the piston rod 23. And a gas spring rod 72 inserted in and out freely.

  An annular oil chamber 17 is defined between the inner periphery of the outer tube 11 and the outer periphery of the inner tube 12, and the first sectional area of the annular oil chamber 17 is formed larger than the second sectional area of the piston rod 23. Yes.

  The hydraulic shock absorber 10 further includes a second piston 73 that is fixed to the end of the gas spring rod 72 on the second direction side and moves inside the gas spring 71.

  The gas spring 71 includes a flange portion 71 </ b> A for fixing the gas spring 71 to the inner tube 12. The suspension spring 33 is provided between the first piston 26 and the flange portion 71A.

(Operation of Hydraulic Shock Absorber According to Embodiment)
The hydraulic shock absorber 10 according to the present embodiment operates as follows.

(Pressure side stroke)
The hydraulic oil corresponding to the entry volume ΔS2 of the piston rod 23 entering the inner tube 12 in the compression side stroke is transferred from the piston rod side oil chamber 21A on the inner periphery of the inner tube 12 through the oil hole 28 of the inner tube 12 to the annular oil chamber 17. It is transferred to. At this time, the volume increase ΔS1 (necessary replenishment amount) of the annular oil chamber 17 is larger than the entry volume ΔS2 of the piston rod 23. For this reason, of the necessary replenishment amount ΔS1 of the hydraulic oil to the annular oil chamber 17, the shortage of (ΔS1-ΔS2) is from the oil chamber 22A of the oil reservoir chamber 22 to the check valve 60, the piston rod side oil chamber 21A, the oil hole The annular oil chamber 17 is replenished through 28.

  In the present embodiment, a gas spring 71 and a gas spring rod 72 are further added. For this reason, the hydraulic oil corresponding to the volume ΔG1 of the gas spring rod 72 entering the gas spring 71 is filled into the piston-side oil chamber 21B from the piston rod-side oil chamber 21A through the extension-side flow path 42 of the first piston 26. The

Here, when the volume of the hydraulic oil filled from the piston rod side oil chamber 21A to the annular oil chamber 17 and the piston side oil chamber 21B is ΔR1,
ΔR1 = (ΔS1−ΔS2) + ΔG1
It becomes. In the present embodiment, the damping force responsiveness is controlled by adjusting the volume ΔR1.

  In the compression side stroke, as described above, a compression side damping force is generated by the passage resistance of the bypass passage 45 whose opening degree is adjusted by the needle valve 44 in the low speed region, and in the middle and high speed region, the compression side is deformed by the deformation of the compression side disk valve 41A. Generates a damping force.

  FIG. 4A is a graph showing a damping force loop R2 of a conventional hydraulic shock absorber, and FIG. 4B is a graph showing a damping force loop R1 of the hydraulic shock absorber 10 according to the embodiment. The vertical axis represents the load (N) acting on the hydraulic shock absorber, and the horizontal axis represents the stroke displacement (mm) of the hydraulic shock absorber.

  As described above, the hydraulic oil corresponding to the volume ΔG1 of the gas spring rod 72 entering the gas spring 71 needs to be supplied from the piston rod side oil chamber 21A to the piston side oil chamber 21B. In the region where the stroke speed of the hydraulic shock absorber is low, the filling of the hydraulic oil from the oil chamber 22A to the piston rod side oil chamber 21A is in time for the gas spring rod 72 to enter the gas spring 71. For this reason, the damping force loop characteristics are not disturbed and are stable.

  On the other hand, in the region where the stroke speed is high, the filling of the hydraulic oil from the oil chamber 22 </ b> A to the piston rod side oil chamber 21 </ b> A is not in time for the gas spring rod 72 entering the gas spring 71. For this reason, dents C1 and C2 that are not generated in the conventional damping force loop R2 are generated in the damping force loop R1. That is, in the pressure side stroke, the filling of the hydraulic oil from the oil chamber 22A to the piston rod side oil chamber 21A is not in time. For this reason, the piston rod side oil chamber 21A is converted to a negative pressure, and the pressure balance is disturbed. Accordingly, dents C1 and C2 are generated in the damping force loop R1. By controlling the dents C1 and C2 generated in the damping force loop R1, the absorbability of impact with a high stroke speed due to road surface unevenness is improved. Further, since the running stability in the medium / low speed range is maintained, it is possible to achieve both the shock absorption in the region where the stroke speed is fast and the running stability in the region where the stroke speed is slow.

(Extension process)
The hydraulic oil corresponding to the withdrawal volume ΔS2 of the piston rod 23 that retreats from the inner tube 12 in the extension stroke is supplied from the annular oil chamber 17 through the oil hole 28 of the inner tube 12 to the piston rod side oil chamber on the inner periphery of the inner tube 12. It is transferred to 21A. At this time, the volume decrease ΔS1 (discharge amount) of the annular oil chamber 17 is larger than the retraction volume (volume decrease) ΔS2 of the piston rod 23. For this reason, of the amount of oil discharged from the annular oil chamber 17, an excess of (ΔS 1 −ΔS 2) is stored in an oil reservoir via a micro flow channel (not shown) formed in the rod guide portion 19 A of the partition wall member 19. The oil is discharged into the oil chamber 22 </ b> A of the chamber 22. In the present embodiment, the hydraulic oil corresponding to the withdrawal volume ΔG1 of the gas spring rod 72 from the gas spring 71 is further supplied from the piston side oil chamber 21B to the piston rod side oil chamber 21A, and the oil from the piston rod side oil chamber 21A. The oil is discharged into the oil chamber 22 </ b> A of the reservoir chamber 22.

  In the extension side stroke, as described above, the extension side damping force is generated by the passage resistance of the bypass passage 45 whose opening degree is adjusted by the needle valve 44 in the low speed region, and the extension side disk valve 42A is bent in the middle and high speed region. The extension side damping force is generated by the deformation. In addition, the extension side damping force is also generated due to the passage resistance of the micro flow path.

  The volume change amount due to the temperature change of the hydraulic oil inside the inner tube 12 is discharged to the oil reservoir chamber 22 through the minute flow path or supplied from the oil reservoir chamber 22 to be compensated.

  When the gas spring rod 72 enters the gas spring 71, the gas enclosed in the gas spring 71 is compressed by the entry volume ΔG1 of the gas spring rod 72. As a result, a rod reaction force that is a spring force corresponding to the rod area of the gas spring rod 72 is generated. When the gas spring 71 is considered to follow the operation of the hydraulic shock absorber, the contained pressure of the gas sealed in the gas spring 71 is the maximum internal pressure of the piston-side oil chamber 21B when a damping force is generated in the compression-side stroke. It is preferable to set the above.

(Effect of embodiment)
Therefore, according to this embodiment, there are the following effects.

  Hydraulic oil corresponding to the entry volume ΔG1 of the gas spring rod 72 entering the gas spring 71 in the compression side stroke is supplied from the piston rod side oil chamber 21A to the piston side oil chamber 21B via the damping force adjusting device 40 of the first piston 26. Is done. In the region where the stroke speed of the compression side stroke is slow, the supply of hydraulic oil from the oil reservoir chamber 22 to the piston rod side oil chamber 21A via the check valve 60 is in time. For this reason, the damping force loop by the damping force adjusting device 40 of the first piston 26 is not disturbed and is stable. On the other hand, in the region where the stroke speed is high, the supply of hydraulic oil from the oil reservoir 22 to the piston rod side oil chamber 21A via the check valve 60 is not in time. For this reason, the pressure balance is disturbed by the piston rod side oil chamber 21A being changed to a negative pressure. As a result, a dent is generated in the damping force loop. The hydraulic shock absorber 10 can positively delay the rising of the damping force in a region where the stroke speed is fast due to the depression of the damping force loop. For this reason, the absorbability of the impact by the unevenness | corrugation of a road surface improves. Thereby, the hydraulic shock absorber 10 can achieve both running stability in a region where the stroke speed is low and shock absorption in a region where the stroke speed is high.

  When the first cross-sectional area S1 of the annular oil chamber 17 is formed larger than the second cross-sectional area S2 of the piston rod 23 (S2 <S1), the volume increase (ΔS1) of the annular oil chamber 17 in the compression stroke is the piston. It becomes larger than the volume increase (ΔS2) of the rod 23. For this reason, the volume increase (ΔS2) of the piston rod 23 is absorbed by the volume increase (ΔS1) of the annular oil chamber 17. Further, the shortage of (ΔS1−ΔS2) is supplied from the oil reservoir chamber 22 to the piston rod side oil chamber 21A via the check valve 60. For this reason, it is possible to prevent air from entering the piston rod side oil chamber 21A from the air chamber 22B.

  A second piston 73 fixed to the tip of the gas spring rod 72 and slidably contacting the inner periphery of the gas spring 71 is provided on the gas spring rod 72. For this reason, the 2nd piston 73 is guided to the inner periphery of the gas spring 71, and the operation | movement of a gas spring rod is stabilized.

  The gas spring 71 has a fixing flange 71A. A suspension spring 33 is provided between the first piston 26 and the flange portion 71A. For this reason, the suspension spring 33 is also used for fixing the gas spring 71, and the configuration of the hydraulic shock absorber 10 becomes simple and compact.

  The present invention can be used, for example, in a hydraulic shock absorber for a vehicle suitable for use in a front fork of a motorcycle. Further, the present invention can be used for, for example, a suspension fork of a bicycle such as a mountain bike.

10 Hydraulic shock absorber 11 Outer tube (first tube)
11A First bush 12 Inner tube (second tube)
12A Second bush 17 Annular oil chamber 19 Partition member 21 Oil chamber
21A Piston rod side oil chamber 21B Piston side oil chamber 22 Oil reservoir chamber 22A Oil chamber 22B Air chamber 23 Piston rod 26 First piston 28 Oil hole 33 Suspension spring 40 Damping force adjusting device 60 Check valve (oil amount adjusting device)
71 Gas spring (gas chamber)
71A collar 72 gas spring rod (gas chamber rod)
73 Second piston

Claims (5)

A first tube;
A second tube that slides inside the first tube and is filled with oil;
A suspension spring disposed inside the second tube;
A piston rod that is fixed at an end in the first direction in the axial direction of the first tube and is inserted into the second tube so as to freely enter and exit;
A first piston that is fixed to a second direction side opposite to the first direction of the piston rod and that generates a damping force while sliding on the inner periphery of the second tube;
A gas spring rod provided on the second direction side of the front Symbol piston rod,
A gas spring provided on the second direction side of the first piston and filled with a gas, wherein the reaction force of the gas spring rod is generated based on the gas compressed by the volume of entry of the gas spring rod A gas spring
A hydraulic shock absorber characterized by comprising: An annular oil chamber is defined between the inner periphery of the first tube and the outer periphery of the second tube;
The hydraulic shock absorber according to claim 1, wherein a first cross-sectional area of the annular oil chamber is formed larger than a second cross-sectional area of the piston rod.   2. The hydraulic shock absorber according to claim 1, further comprising a second piston fixed to an end of the gas chamber rod on the second direction side and moving inside the gas chamber. A collar for fixing the gas chamber to the second tube;
The hydraulic shock absorber according to claim 1, wherein the suspension spring is provided between the first piston and the flange portion. A first tube;
A second tube that slides inside the first tube and is filled with oil;
A suspension spring disposed inside the second tube;
A piston rod that is fixed at an end in the first direction in the axial direction of the first tube and is inserted into the second tube so as to freely enter and exit;
A first piston that is fixed to a second direction side opposite to the first direction of the piston rod and that generates a damping force while sliding on the inner periphery of the second tube;
A gas chamber provided on the second direction side of the first piston;
A gas chamber rod provided on the second direction side of the piston rod and inserted into the gas chamber so as to freely enter and exit;
A collar for fixing the gas chamber to the second tube;
The hydraulic shock absorber according to claim 1, wherein the suspension spring is provided between the first piston and the flange portion.

Images