JP5212812B2 - Hydraulic buffer - Google Patents

Description

  The present invention relates to a hydraulic shock absorber employed in a railway vehicle or the like.

In the conventional hydraulic shock absorber, as in the air vent structure in the cylinder, as in Patent Document 1, an annular plate is integrally provided on the end surface of the rod guide, thereby communicating with the oil passage between the annular plate and the inner cylinder. A hydraulic shock absorber is disclosed in which a gas passage mixed in the pressure oil in the rod side oil chamber when the piston rod is expanded and contracted is guided to the oil passage side by the communication passage or the like and discharged into the reservoir chamber. .
JP, 11-13815, A As another method, a disk-like plate is arranged in a piston, and an uneven part is formed in the plate, thereby forming a communication path between the bottom side liquid chamber and the rod side liquid chamber. In some cases, a gas such as air staying in the bottom side liquid chamber is caused to flow from the communication path of the plate to the rod side liquid chamber along with the working fluid during the contracting stroke, and discharged to the outside of the cylinder.

  However, in the prior art, for example, when a malfunction occurs in the sliding stroke of the piston, and the piston collides with the bottom of the cylinder, the communication path is blocked, and the bottom side liquid chamber and the rod There is a possibility that the flow between the side liquid chamber is hindered and the expansion and contraction operation of the piston rod is affected.

  An object of the present invention is to prevent a malfunction of the venting communication path, and even if a malfunction occurs in the communication path, the piston rod does not hinder the flow between the bottom side liquid chamber and the rod side liquid chamber. An object of the present invention is to provide a hydraulic shock absorber capable of continuing the expansion and contraction operation.

As a means for solving the above-mentioned problems, the invention described in claim 1 of the present invention includes a cylinder in which hydraulic fluid is sealed, and a rod-side liquid chamber that is slidably inserted into the cylinder. And a piston defined in the bottom side liquid chamber, a passage provided in the piston for communicating the rod side liquid chamber and the bottom side liquid chamber, one end connected to the piston, and the other end A piston rod protruding outside through a rod guide that closes the end of the cylinder;
Mounted in a horizontal state, provided with a reservoir connected to the cylinder and filled with hydraulic fluid and gas, and a damping force generation mechanism that generates a damping force by controlling the flow of hydraulic fluid generated by sliding of the piston is a hydraulic shock absorber, forming an annular portion protruding bottom side an annular provided on an end face of the bottom-side liquid chamber side of the piston, the disk-shaped plate so as to abut the annular portion The plate is disposed at a position directly facing the bottom portion on the bottom side liquid chamber side, and faces the space surrounded by the plate and the inside of the annular portion on the bottom side liquid chamber side of the piston A plurality of communication holes are penetrated from the annular portion, and the passage and the bottom liquid side chamber communicate with each other through the plurality of communication holes and the space.
Further, the invention of claim 2 forms an annular portion that is provided on the end surface of the piston on the bottom side liquid chamber side and protrudes toward the bottom side, and the cylinder is configured so as to come into contact with the annular portion. A disk-shaped plate having a diameter smaller than the inner diameter is attached, and the plate is disposed at a position directly facing the bottom portion on the bottom side liquid chamber side, and the piston on the contact surface of the annular portion with the plate A recess surrounded by an inner side of the annular portion on the bottom side liquid chamber side, a space surrounded by the plate, and a cylinder that forms a communication path between the bottom side liquid chamber and facing the axial direction of the cylinder. The passage and the bottom-side liquid chamber are communicated with each other via a gap.
Furthermore, in the invention of claim 3, in particular, an annular portion provided on the end surface of the piston on the bottom side chamber side and projecting toward the bottom side is formed, and the inner diameter of the cylinder is in contact with the annular portion. also attached is a small diameter disk-shaped plate, the plate is arranged at a position you directly opposite the bottom portion of the bottom side liquid chamber side, the contact surface between the annular portion of the plate, the piston A concave portion facing the axial direction of a cylinder forming a communication path between the inner side of the annular part on the bottom side liquid chamber side, the space surrounded by the plate, and the bottom side liquid chamber is formed, and the communication path and the space are interposed therebetween. The passage and the bottom-side liquid chamber communicate with each other, and a communication hole is penetrated through the plate at a position facing the space, and the passage and the bottom are communicated with the communication hole and the space. Liquid side chamber and It is characterized in that the communicated.

  According to the hydraulic shock absorber of the present invention, it is possible to prevent a malfunction of the venting communication path, and even if a malfunction occurs in the communication path, the flow between the bottom side liquid chamber and the rod side liquid chamber is hindered. The expansion / contraction operation of the piston rod can be continued.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to FIGS.
The hydraulic shock absorber according to the embodiment of the present invention is provided as a hydraulic shock absorber in which hydraulic oil is employed as the hydraulic fluid. More specifically, the hydraulic shock absorber according to the embodiment of the present invention is a so-called uniflow type that is used in a horizontally placed state and the flow of hydraulic oil is only in one direction, and is used as a carriage yaw damper or a left and right movement damper for a railway vehicle. Provided. In the following description, for convenience of explanation, the right side in the drawing is described as one end side, and the left side in the drawing is appropriately described as the other end side.

First, a hydraulic shock absorber 1 according to a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the hydraulic shock absorber 1 according to the first embodiment of the present invention has an outer cylinder 2 and an inner cylinder 3 that is a cylinder with a gap between the outer cylinder 2 and the inner cylinder 3. And are arranged concentrically. One end opening of the outer cylinder 2 is closed by the lid portion 5, and one end opening of the inner cylinder 3 is closed by the bottom portion 6. The lid portion 5 and the bottom portion 6 are integrally configured by fitting one end portion of the bottom portion 6 into the recessed portion provided in the lid portion 5 until the bottom is attached. The other end openings of the outer cylinder 2 and the inner cylinder 3 are closed by a rod guide 8 that guides the piston rod 7 extending from the inner cylinder 3 in a fluid-tight manner in a slidable manner. An annular space between the outer cylinder 2 and the inner cylinder 3 functions as the reservoir 13.

A piston 10 is slidably inserted into the inner cylinder 3, and the inside of the inner cylinder 3 is defined by the piston 10 as a bottom side liquid chamber 11 and a rod side liquid chamber 12. On the end surface of the piston 10 on the bottom side liquid chamber 11 side, a concave portion 15 in which a nut 16 for fixing the piston rod is accommodated is formed. One end of the piston rod 7 is inserted into the piston 10 and fixed by a nut 16, and the other end of the piston rod 7 is supported by the rod guide 8 so as to be slidable in a liquid-tight manner. 2 protrudes outside.
Note that an orifice 20 is formed in the upper portion of the peripheral wall portion of the inner cylinder 3 adjacent to the rod guide 8. The orifice 20 functions as a damping force generating mechanism for generating a damping force when hydraulic oil in the bottom side liquid chamber 12 flows into the reservoir 13 and for venting the gas in the bottom side liquid chamber 12.
The bottom side liquid chamber 11 and the rod side liquid chamber 12 in the inner cylinder 3 are filled with hydraulic oil, and the hydraulic oil is partially sealed in the reservoir 13. Gas is retained.

As shown in FIGS. 1 and 3, a bottom portion check valve 21 as a check valve that allows only flow from the reservoir 13 to the bottom-side liquid chamber 11 is provided in the bottom portion 6 that closes one end opening of the inner cylinder 3. It is arranged.
The piston 10 is also provided with a piston check valve 23 that allows flow from the bottom side liquid chamber 11 to the rod side liquid chamber 12 during the contraction stroke of the piston rod 7. The piston portion check valve 23 is provided with a plurality of passages provided in the piston 10 as passages that open the bottom surface of the concave portion 15 and penetrate the axial direction through the bottom side liquid chamber 11 and the rod side liquid chamber 12. A valve body 26 that allows the through hole 25 to be opened and closed from the rod side liquid chamber 12 side, and a compression spring that urges the valve body 26 against the end surface of the piston 10 on the rod side liquid chamber 12 side to close each through hole 25. 27.
Further, the rod guide 8 is provided with a rod guide portion as a damping force generating mechanism that generates a damping force when the hydraulic oil in the rod side liquid chamber 12 flows into the reservoir 13 during the contraction stroke and the extension stroke of the piston rod 7. A pressure valve 29 is provided.

As shown in FIG. 2 and FIG. 3, the bottom surface of the piston 10 on the bottom side liquid chamber 11 side has a recess 15 that accommodates the nut 16 in a substantially central portion, and the recess 15 continuously from the recess 15 to one end side. A large-diameter concave portion 31 having a diameter larger than the inner diameter of the inner peripheral portion and an annular contact portion 32 that is disposed around the large-diameter concave portion 31 and to which the disk-shaped plate 33 is abutted and fixed are formed. The outer diameter of the annular contact portion 32 substantially matches the inner diameter of the inner cylinder 3.
On the other hand, the plate 33 is fixed by the bolt 34 in a state where the plate 33 is in contact with the annular contact portion 32 provided on the end surface of the piston 10 on the bottom liquid chamber 11 side. Thereby, as shown in FIG. 1, the plate 33 is disposed so as to directly face the bottom portion 6.
The outer diameter of the plate 33 substantially matches the outer diameter of the annular contact portion 32. Further, the plate 33 has a bottom side liquid chamber 11 and each through hole 25 of the piston 10 at a portion facing the bottom of the large-diameter recess 31 inside a portion 35 that overlaps the annular contact portion 32 in a plan view. A plurality of substantially circular communication holes 37 that communicate with each other are formed along the circumferential direction (24 in the present embodiment). That is, the plate 33 has a plurality of communication holes 37 in the circumferential direction at positions facing the space 36 surrounded by the inner side of the annular contact portion 32 provided on the bottom side liquid chamber 11 side of the piston 10 and the plate 33. It is formed along. These communication holes 37 function as communication holes that allow the working oil and gas in the bottom side liquid chamber 11 to flow to the through hole 25 of the piston 10 via the space 36 during the contraction stroke of the piston rod 7. Each communication hole 37 is disposed near the overlapping portion 35 of the plate 33, that is, near the annular contact portion 32 of the piston 10, and the gas staying in the upper part in the bottom side liquid chamber 11 easily flows to the rod side liquid chamber 12. For this reason, it is preferable to dispose it as close to the inner peripheral surface of the inner cylinder 3 as possible.
These communication holes 37 have an opening area so that a damping force due to the flow resistance is not generated as much as possible to the hydraulic fluid flowing from the bottom side liquid chamber 11 to the rod side liquid chamber 12 during the contraction stroke of the piston rod 7. Is adjusted to a predetermined value.

Next, the operation of the hydraulic shock absorber 1 according to the first embodiment of the present invention will be described.
The hydraulic shock absorber 1 includes a carriage 38 and a vehicle body via a bracket 38 fixed to the other end of the piston rod 7 and a bracket 39 fixed to the lid 5 that closes one end opening of the outer cylinder 2. It is attached in a horizontal state between. When the vehicle body and the carriage move relative to each other, the piston rod 7 expands and contracts while generating a damping force.
First, in the extension stroke of the piston rod 7, the piston 10 slides in the direction of compressing the hydraulic oil in the rod side liquid chamber 12, so that the rod side liquid chamber 12 is pressurized and the piston check valve 23 is closed. The hydraulic oil flows from the rod side liquid chamber 12 into the reservoir 13 through the orifice 20 and the rod guide part pressure regulating valve 29, and a predetermined damping force is generated by the orifice 20 and the rod guide part pressure regulating valve 29. At this time, the hydraulic oil in the reservoir 13 flows into the bottom side liquid chamber 11 through the bottom check valve 21.

  On the other hand, in the contraction stroke of the piston rod 7, the piston 10 slides so as to compress the hydraulic oil in the bottom side liquid chamber 11, whereby the bottom side liquid chamber 11 is pressurized and the piston check valve 23 opens. The hydraulic oil flows from the bottom-side liquid chamber 11 to the rod-side liquid chamber 12, and the hydraulic oil that has entered the rod-side liquid chamber 12 from the rod-side liquid chamber 12 passes through the orifice 20 and the rod guide. It flows into the reservoir 13 via the partial pressure regulating valve 29, and a predetermined damping force is generated by the orifice 20 and the rod guide pressure regulating valve 29. At this time, the hydraulic oil in the reservoir 13 flows into the bottom side liquid chamber 11 through the bottom check valve 21. As a result, gas such as air that has accumulated in the upper part of the bottom side liquid chamber 11 and gas mixed in the hydraulic oil enter each communication hole 37 of the plate 33, the space 36, and the piston check valve 23 together with the hydraulic oil. Passes and flows into the rod side liquid chamber 12. The gas flowing into the rod side liquid chamber 12 mainly flows from the orifice 20 provided on the upper wall portion of the inner cylinder 3 to the reservoir 13. In this way, gas (bubbles) such as air staying in the bottom side liquid chamber 11 can smoothly flow out to the reservoir 13.

  According to the hydraulic shock absorber 1 according to the first embodiment of the present invention, for example, even when the piston 10 has a stroke of a set value or more and collides with the bottom portion 6, the plate Since each communication hole 37 of 33 is not obstruct | occluded, a big trouble does not appear in the expansion / contraction operation | movement of the subsequent piston rod 7, but expansion / contraction operation | movement can be continued.

Next, a hydraulic shock absorber 1a according to a second embodiment of the present invention will be described with reference to FIGS. In the description of the hydraulic shock absorber 1a according to the second embodiment of the present invention, only differences from the hydraulic shock absorber 1 according to the first embodiment will be described.
On the end surface of the piston 10 on the bottom side liquid chamber 11 side, an annular portion 40 is formed around the recess 15 that accommodates the nut 16 provided at the substantially central portion. A disc-shaped plate 33a is brought into contact with and fixed to the annular portion 40. The plate 33 a is formed to be slightly smaller in diameter than the inner diameter of the inner cylinder 3, and an annular passage 45 is formed between the inner surface of the inner cylinder 3. Further, the plate 33a is formed to have a slightly smaller diameter than the outer diameter of the annular portion 40.
The annular portion 40 has an outer diameter smaller than the inner diameter of the inner cylinder 3, and a slight gap is formed between the annular portion 40 and the inner peripheral surface of the inner cylinder 3. Further, a plurality of convex contact portions 43 having a predetermined width and height are formed in the annular portion 40 in a radial manner, so that the concave portions 44 (four locations in the present embodiment) are provided between the convex contact portions 43. ) Is formed. These concave portions 44 function as a communication passage 42 formed between the plate 33a and the annular portion 40 of the piston 10, and the annular passage 45, the communication passage 42 and the annular portion provided on the bottom side liquid chamber 11 side of the piston 10 are provided. The bottom side liquid chamber 11 and each through hole 25 of the piston 10 communicate with each other through a space 36 surrounded by the inside of the plate 40 and the plate 33.

Next, the operation of the hydraulic shock absorber 1a according to the second embodiment will be described.
First, since the action at the time of extension stroke of the piston rod 7 is the same as the action at the time of extension stroke of the piston rod 7 in the hydraulic shock absorber 1 according to the first embodiment, description thereof is omitted here.
On the other hand, in the contraction stroke of the piston rod 7, the hydraulic oil in the bottom side liquid chamber 11 is checked from the annular passage 45, each recess 44 (communication passage 42) provided in the annular portion 40 of the piston 10, and the space 36. It flows into the rod side liquid chamber 12 through the valve 23. At this time, a gas such as air staying in the upper part in the bottom side liquid chamber 11 and a gas mixed in the hydraulic oil flow into the rod side liquid chamber 12 together with the hydraulic oil, and the orifice 20 ( 1) to the reservoir 13.

  According to the hydraulic shock absorber 1a according to the second embodiment of the present invention, for example, even when the piston 10 has a stroke of a set value or more and collides with the bottom portion 6, the plate 33a Is flat and difficult to deform. Therefore, the recesses 44 are not completely closed, and the expansion / contraction operation of the piston rod 7 is not hindered and the expansion / contraction operation can be continued.

As shown by the two-dot chain line in FIG. 4, the bottom of the recess 15 faces the plate 33a inside the portion 35a that overlaps the annular portion 40 provided on the bottom side liquid chamber 11 side of the piston 10 in plan view. Even if a communication hole 41 that connects the bottom-side liquid chamber 11 and each through-hole 25 of the piston 10 is formed at a position, that is, a position facing the space 36 surrounded by the inside of the annular portion 40 and the plate 33. Good. Further, the communication hole 41 has an opening area that prevents a damping force from being generated as much as possible due to a flow resistance with respect to the hydraulic fluid flowing from the bottom side liquid chamber 11 to the rod side liquid chamber 12 during the contraction stroke of the piston rod 7. It has been adjusted as follows. In the embodiment of FIG. 4, one communication hole 41 is formed, but a plurality of communication holes 41 may be formed.
Thereby, due to a malfunction of the piston stroke, the piston 10 should collide with the bottom portion 6, and each recess 44 (communication path 42) of the annular portion 40 provided on the end surface of the piston 10 on the bottom side liquid chamber 11 side is completely completed. Even if closed, the communication hole 41 ensures the flow between the bottom side liquid chamber 11 and the rod side liquid chamber 12.

Next, a hydraulic shock absorber 1b according to a third embodiment of the present invention will be described with reference to FIGS. In the description of the hydraulic shock absorber 1b according to the third embodiment of the present invention, only differences from the hydraulic shock absorber 1 according to the first embodiment will be described.
An annular contact portion 32 ′ to which the plate 33b is abutted and fixed is formed on the outer peripheral portion of the end surface of the piston 10 on the bottom side liquid chamber 11 side. The outer diameter of the annular contact portion 32 ′ substantially matches the inner diameter of the inner cylinder 3.
On the other hand, the plate 33 b is formed to have a slightly smaller diameter than the inner diameter of the inner cylinder 3, and an annular passage 45 is formed between the inner surface of the inner cylinder 3. Further, the plate 33b has a portion facing the bottom of the recess 15 inside the portion 35b overlapping the annular contact portion 32 ′ provided on the bottom side liquid chamber 11 side of the piston 10 in plan view, that is, the annular contact portion 32. One or a plurality of communication holes 41 for communicating the bottom-side liquid chamber 11 and the through holes 25 of the piston 10 are formed at positions facing the space 36 surrounded by the inner side of the plate 33 and the plate 33 (FIG. 6). And one in FIG. 7). As described above, the communication hole 41 prevents a damping force from being generated as much as possible by the flow resistance with respect to the hydraulic fluid that flows from the bottom side liquid chamber 11 to the rod side liquid chamber 12 during the stroke of the piston rod 7 contracting. It is adjusted so as to have a large opening area.
Further, on the plate 33b, a plurality of convex contact portions 50 (four in the present embodiment) having a predetermined width and height are radially formed in a portion 35b overlapping the annular contact portion 32 ′ in plan view. By doing so, each recessed part 51 is formed between each convex contact part 50. FIG. These concave portions 51 function as a communication passage 42 formed between the plate 33b and the annular contact portion 32 'of the piston 10, and are provided on the annular passage 45, the communication passage 42, and the bottom side liquid chamber 11 side of the piston 10. The space 36 surrounded by the inner side of the annular contact portion 32 ′ and the plate 33 communicates the bottom side liquid chamber 11 and the through holes 25 of the piston 10.

Next, a hydraulic shock absorber 1c according to a fourth embodiment of the present invention will be described with reference to FIGS. Note that a plate 33c slightly different from the plate 33b used in the hydraulic shock absorber 1b according to the third embodiment is employed in the hydraulic shock absorber 1c according to the fourth embodiment of the present invention.
On the plate 33c, a convex contact portion 52 is formed in the range of approximately a half circumference of the portion 35c overlapping the annular contact portion 32 ′ in plan view, and a concave portion 53 is formed in the remaining portion. The concave portion 53 functions as a communication passage 42 formed between the plate 33c and the annular contact portion 32 'of the piston 10, and the bottom side liquid chamber 11 and the piston are formed by the annular passage 45, the communication passage 42 and the space 36. The ten through holes 25 communicate with each other.
In addition, in the hydraulic shock absorber 1c according to the fourth embodiment, with the hydraulic shock absorber 1c attached, as shown in FIG. 9, it is more degassed if the concave portion 53 of the plate 33c is positioned on the upper side. This is preferable.

Next, the operation of the hydraulic shock absorbers 1b and 1c according to the third and fourth embodiments will be described.
First, since the action during the extension stroke of the piston rod 7 is the same as the action during the extension stroke of the piston rod 7 in the hydraulic shock absorbers 1 and 1a according to the first and second embodiments, the description thereof is omitted here. To do.
On the other hand, in the contraction stroke of the piston rod 7, the hydraulic oil in the bottom side liquid chamber 11 flows from the recesses 51 and 53 (communication passage 42) and the space 36 provided in the annular passage 45, the plates 33b and 33c, The fluid flows into the rod side liquid chamber 12 through the piston check valve 23 from the communication hole 41 provided in 33b and 33c. At the same time, the gas such as air staying in the upper part of the bottom side liquid chamber 11 and the gas mixed in the hydraulic oil are mainly formed in the recesses 51 and 53 and the spaces provided in the annular passage 45 and the plates 33b and 33c. 36 passes through the piston check valve 23 and flows into the rod side liquid chamber 12 together with the hydraulic oil, and flows into the reservoir 13 from the orifice 20 (see FIG. 1) provided in the inner cylinder 3.
Then, according to the hydraulic shock absorbers 1b and 1c according to the third and fourth embodiments of the present invention, for example, when the piston 10 has collided with the bottom portion 6 with a stroke greater than or equal to the set value. Even if the recesses 51 and 53 provided in the plates 33b and 33c are deformed and the communication passage 42 is completely closed, the communication hole 41 of the plates 33b and 33c is not closed. The telescopic motion of 7 is not greatly hindered, and the telescopic motion can be continued.

FIG. 1 is a sectional view showing a hydraulic shock absorber according to a first embodiment of the present invention. FIG. 2 is a view taken in the direction of arrow A in FIG. FIG. 3 is an enlarged view of the piston portion of FIG. FIG. 4 is a hydraulic shock absorber according to the second embodiment of the present invention, and is a view seen from the same direction as FIG. FIG. 5 is an enlarged view of the piston portion of the hydraulic shock absorber according to the second embodiment of the present invention. FIG. 6 is a perspective view of a plate employed in the hydraulic shock absorber according to the third embodiment of the present invention. FIG. 7 is an enlarged view of the piston portion of the hydraulic shock absorber according to the third embodiment of the present invention. FIG. 8 is a perspective view of a plate employed in the hydraulic shock absorber according to the fourth embodiment of the present invention. FIG. 9 is an enlarged view of the piston portion of the hydraulic shock absorber according to the fourth embodiment of the present invention.

Explanation of symbols

  1, 1a, 1b, 1c Hydraulic shock absorber (hydraulic pressure shock absorber), 2 outer cylinder, 3 inner cylinder (cylinder), 6 bottom part, 7 piston rod, 8 rod guide, 10 piston, 11 bottom side liquid chamber, 12 Rod side liquid chamber, 13 reservoir, 20 orifice (damping force generating mechanism), 25 through hole (passage), 29 rod guide pressure regulating valve (damping force generating mechanism), 32, 32 ′ annular contact portion, 40 annular portion, 33 , 33a, 33b, 33c plate, 36 space, 37, 41 communication hole, 42 communication path, 43 convex contact part, 44, 51, 53 recess, 45 annular path

Claims (3)

A cylinder filled with hydraulic fluid;
A piston that is slidably inserted into the cylinder and defines the inside of the cylinder into a rod side liquid chamber and a bottom side liquid chamber;
A passage provided in the piston for communicating the rod side liquid chamber and the bottom side liquid chamber;
A piston rod having one end connected to the piston and the other end protruding outside via a rod guide that closes the end of the cylinder;
A reservoir connected to the cylinder and filled with hydraulic fluid and gas;
A hydraulic shock absorber mounted in a horizontal state, comprising a damping force generation mechanism that generates a damping force by controlling a flow of hydraulic fluid generated by sliding of the piston,
Forming an annular portion protruding to the bottom side an annular provided on an end face of the bottom-side liquid chamber side of the piston, disc-shaped plate is attached so as to abut the annular portion, the plate wherein the bottom side A plurality of communication paths are provided at positions directly opposite to the bottom portion on the liquid chamber side and from the inside of the annular portion on the bottom side liquid chamber side of the piston and the annular portion of the plate facing the space surrounded by the plate. A hydraulic shock absorber characterized in that a hole is penetrated and the passage and the bottom liquid side chamber communicate with each other through the plurality of communication holes and the space. A cylinder filled with hydraulic fluid;
A piston that is slidably inserted into the cylinder and defines the inside of the cylinder into a rod side liquid chamber and a bottom side liquid chamber;
A passage provided in the piston for communicating the rod side liquid chamber and the bottom side liquid chamber;
A piston rod having one end connected to the piston and the other end protruding outside via a rod guide that closes the end of the cylinder;
A reservoir connected to the cylinder and filled with hydraulic fluid and gas;
A hydraulic shock absorber mounted in a horizontal state, comprising a damping force generation mechanism that generates a damping force by controlling a flow of hydraulic fluid generated by sliding of the piston,
An annular annular portion provided on the bottom side liquid chamber side end surface of the piston is formed so as to protrude to the bottom side, and a disk-shaped plate having a smaller diameter than the inner diameter of the cylinder is attached so as to contact the annular portion. The plate is disposed at a position directly facing the bottom portion on the bottom side liquid chamber side, and the annular portion on the bottom side liquid chamber side of the piston is disposed on a contact surface of the annular portion with the plate. A recess is formed in the axial direction of the cylinder that forms a communication path between the inside and the space surrounded by the plate and the bottom side liquid chamber, and the passage and the bottom side liquid chamber are formed via the communication path and the space. And a hydraulic shock absorber characterized by being communicated with each other. A cylinder filled with hydraulic fluid;
A piston that is slidably inserted into the cylinder and defines the inside of the cylinder into a rod side liquid chamber and a bottom side liquid chamber;
A passage provided in the piston for communicating the rod side liquid chamber and the bottom side liquid chamber;
A piston rod having one end connected to the piston and the other end protruding outside via a rod guide that closes the end of the cylinder;
A reservoir connected to the cylinder and filled with hydraulic fluid and gas;
A hydraulic shock absorber mounted in a horizontal state, comprising a damping force generation mechanism that generates a damping force by controlling a flow of hydraulic fluid generated by sliding of the piston,
An annular part provided on the end surface of the piston on the bottom side chamber side and projecting to the bottom side is formed, and a disk-shaped plate having a smaller diameter than the inner diameter of the cylinder is attached so as to contact the annular part, the plate is arranged at a position you directly opposite the bottom portion of the bottom side liquid chamber side, the contact surface between the annular portion of the plate, said annular portion inner side of the bottom side liquid chamber side of the piston And a recess facing in the axial direction of a cylinder forming a communication path between the space surrounded by the plate and the bottom liquid chamber, and the passage and the bottom liquid chamber are connected to each other through the communication path and the space. Further, the plate further includes a communication hole penetrating through the plate at a position facing the space, and the passage and the bottom liquid side chamber communicate with each other through the communication hole and the space. Hydraulic pressure relaxation Vessel.

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