JP2014240700A - Damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a damper which is interposed between a vehicle body and wheels, and attenuates road face vibration inputted to the wheels.SOLUTION: A damper comprises: a damper main body in which a wheel-side tube 2 is inserted into a vehicle body side tube 1 via a pair of vertical bearings 30, 31, the upper-side bearing 30 is attached to an external periphery of the wheel-side tube 2 and the lower-side bearing 31 is attached to an internal periphery of the vehicle body side tube 1, and a lubrication gap 3 is formed between the bearings 30, 31; an air chamber G and a working fluid chamber R which are formed between the damper 4 which is accommodated in the damper main body and the damper main body; a rod guide 6 for partitioning the working fluid chamber R to up-and-down directions (R1, R2); a flow passage L having a check valve 6 which permits only the movement of a working fluid to the lower-side working fluid chamber R2 from the upper-side working fluid chamber R1; and a communication passage 2a which makes the lower-side working fluid chamber R2 and the lubrication gap 3 communicate with each other. The movement of the working fluid to the upper-side working fluid chamber R1 from the lower-side working fluid chamber R2 is prohibited, and a cross section area of the lubrication gap 3 is larger than a cross section area X of a rod 42 of the damper 4.

Description

  The present invention relates to an improvement in a shock absorber that is interposed between a vehicle body and a wheel and attenuates road surface vibration input to the wheel.

  A shock absorber that is interposed between a vehicle body and a wheel and attenuates road surface vibration input to the wheel is embodied in, for example, a front fork that suspends a front wheel of a motorcycle as disclosed in FIG. And a shock absorber body including a vehicle body side tube and a vehicle body side tube that is slidably inserted into the vehicle body side tube via a pair of upper and lower bearings.

  In the shock absorber body, the upper bearing is attached to the outer circumference of the wheel side tube, and the lower bearing is attached to the inner circumference of the vehicle body side tube. The working fluid contained in the lubrication gap formed between these bearings is slid. Functions as a lubricant to improve the mobility.

  Further, in the shock absorber body, a cylinder that stands up at the axial center of the wheel side tube and is filled with a working fluid, a piston that slidably contacts the inner periphery of the cylinder and divides the inside of the cylinder into two working chambers, An upright damper having a rod protruding and retracting into the cylinder via the piston is accommodated, and a reservoir chamber is formed between the shock absorber body and the damper.

  The reservoir chamber is composed of an air chamber and a working fluid chamber, and compensates for the working fluid that is excessive or insufficient in the cylinder of the rod by means of a base member provided at the bottom of the cylinder to compensate the volume of the damper.

  The working fluid chamber of the reservoir chamber communicates with the lubrication gap via a flow path, and a check valve that allows only the movement of the working fluid from the working fluid chamber to the lubrication gap is provided in the middle of the flow path. Is provided.

  By providing the above configuration, when the front fork is compressed, the working fluid that is excessive due to the rod entry flows out into the working fluid chamber through the base member, and the volume of the lubricating gap increases. A pressure difference is generated between them, the check valve is opened, and the working fluid flows into the lubrication gap through the flow path.

  On the other hand, when the front fork is extended, the lubrication gap is compressed and the check valve is urged by the internal pressure to close the check valve.

  Therefore, when the front fork repeatedly expands and contracts, a so-called pumping operation is performed, the working fluid is sucked into the lubrication gap, the liquid level in the lubrication gap becomes higher, and the working fluid is supplied to the sliding surface of the upper bearing. It becomes possible to make it easy.

  However, in the front fork, when the pressure difference between the working fluid chamber and the lubrication gap is small, the check valve does not open, so the working fluid is not sufficiently supplied to the sliding surface of the upper bearing, and the lubrication is insufficient. There is a risk of becoming.

  Therefore, in Patent Document 1, as described in FIG. 3 of Patent Document 1, the working fluid chamber is partitioned vertically by a rod guide, and a communication passage that communicates the upper and lower working fluid chambers with the rod guide is formed. A damping valve that provides resistance when the working fluid moves from the lower working fluid chamber to the upper working fluid chamber in the communication path, and the lower working fluid chamber communicates with the lubrication gap via the check valve. did.

  As a result, when the front fork is compressed, the internal pressure of the lower working fluid chamber is increased to cause a pressure difference, and the working fluid is reliably supplied to the sliding surface of the upper bearing.

Japanese Patent Laid-Open No. 04-31221

  In order to reliably lubricate the sliding surface of the upper bearing in the conventional front fork, it is necessary to provide a damping valve on the rod guide in addition to the check valve, which causes a problem that the structure becomes complicated.

  Therefore, an object of the present invention is to provide a shock absorber that is embodied in a front fork or the like that can reliably lubricate the sliding surface of the upper bearing without complicating the structure. .

  Means for solving the above problems comprises a vehicle body side tube and a wheel side tube slidably inserted into the vehicle body side tube via a pair of upper and lower bearings, and the upper bearing is the wheel side tube. A lower bearing is attached to the inner periphery of the vehicle body side tube on the outer periphery, and a shock absorber body in which a lubrication gap is formed between the bearings and a shaft center portion of the wheel side tube stand up to contain the working fluid A damper having a cylinder, a piston that slidably contacts the inner periphery of the cylinder and divides the inside of the cylinder into two working chambers, and a rod that protrudes and retracts into the cylinder via the piston, the shock absorber body, and the damper And a reservoir chamber that is made up of an air chamber and a working fluid chamber and supplements the working fluid in excess or deficiency in the damper, and divides the working fluid chamber vertically. A partition member, a flow path having a check valve that is formed in the partition member and allows only movement of the working fluid from the upper working fluid chamber to the lower working fluid chamber, the lower working fluid chamber, and the above A communication passage communicating with the lubrication gap, the movement of the working fluid from the lower working fluid chamber to the upper working fluid is prevented, and the cross-sectional area of the lubrication gap is larger than the cross-sectional area of the rod. Is bigger.

  According to the present invention, the flow path formed in the partition member has the check valve, and the cross-sectional area of the rod and the lubrication gap is different. Therefore, when the shock absorber is expanded or compressed, the sliding surface of the upper bearing is It becomes possible to lubricate reliably. Moreover, since the structure for it is simple, a buffer is not complicated.

It is a front view which partially cuts and shows the front fork which is a buffer in the reference form of the present invention. It is a longitudinal cross-sectional view which expands and shows the principal part of the front fork which is a buffer in the reference form of this invention. It is a principle figure which shows the longitudinal cross-section of the front fork which is a buffer in the reference form of this invention. The arrow on the left side (a) of the center line indicates the direction of movement of the working fluid during expansion. The arrow on the right side (b) of the center line indicates the direction of movement of the working fluid during compression. It is a principle figure which shows the longitudinal cross-section of the front fork which is a buffer in one embodiment of this invention. The arrow on the left side (a) of the center line indicates the direction of movement of the working fluid during expansion. The arrow on the right side (b) of the center line indicates the direction of movement of the working fluid during compression.

  Hereinafter, a shock absorber showing a mode for carrying out the present invention will be described with reference to the drawings. The same reference numerals given throughout the several drawings indicate the same or corresponding parts.

  A shock absorber according to a reference embodiment of the present invention is embodied in a front fork that is interposed between a vehicle body and a front wheel of a two-wheeled vehicle and attenuates road surface vibration input to the front wheel.

  As shown in FIG. 1, the front fork includes a vehicle body side tube 1 and a wheel side tube 2 slidably inserted into the vehicle body side tube 1 via a pair of upper and lower bearings 30 and 31. The upper bearing 30 is attached to the outer periphery of the wheel side tube 2 and the lower bearing 31 is attached to the inner periphery of the vehicle body side tube 1 to form a lubrication gap 3 between the bearings 30 and 31.

  The front fork includes a cylinder 40 that stands up at the axial center of the wheel-side tube 2 and accommodates a working fluid, and is slidably contacted with the inner periphery of the cylinder 40 so that the inside of the cylinder 40 has two working chambers A and B. And a damper 4 having a piston 41 partitioned into the cylinder 40 and a rod 42 protruding and retracting into the cylinder 40 via the piston 41.

  The front fork includes a reservoir chamber formed between the shock absorber body and the damper 4, and the reservoir chamber includes an air chamber G and a working fluid chamber R. Make up for the lack of working fluid.

  Further, the front fork includes a rod guide 5 that is a partition member that divides the working fluid chamber R into upper and lower portions (R1, R2), and a lower working fluid that is formed in the rod guide 5 and that extends from the upper working fluid chamber R1. A flow path L (FIG. 2) having a check valve 6 that allows only movement of the working fluid to the chamber R2, and a communication passage 2a that communicates the lower working fluid chamber R2 and the lubrication gap 3. The cross-sectional area Y of the lubricating gap 3 is formed smaller than the cross-sectional area X of the rod 42 (FIG. 3).

  The front fork according to the present embodiment will be described in detail below. The front fork is an inverted front fork in which the wheel side tube 2 appears and disappears in the vehicle body side tube 1.

  The upper and lower openings of the shock absorber body composed of the vehicle body side tube 1 and the wheel side tube 2 are a cap member 10 provided at the upper end of the vehicle body side tube 1 in the figure and a bottom screwed to the outer periphery of the wheel side tube 2. Each of the members 20 is sealed.

  Further, an opening of a cylindrical gap including a lubrication gap 3 formed between the vehicle body side tube 1 and the wheel side tube 2 is provided on the inner periphery of the lower end portion of the vehicle body side tube 1 and slides on the outer periphery of the wheel side tube 2. The working fluid and gas that are sealed by the sealing member 11 that comes into contact with and are accommodated in the shock absorber body do not leak out.

  The upper bearing 30 attached to the outer periphery of the wheel side tube 2 is engaged in a groove 2b formed on the outer periphery of the upper end portion of the wheel side tube 2, and is in sliding contact with the inner periphery of the vehicle body side tube 1.

  Further, a lower bearing 31 attached to the inner periphery of the vehicle body side tube 1 includes an annular metal member 12 provided immediately above the seal member 11 and a step portion 1 a formed on the inner periphery of the vehicle body side tube 1. It is positioned between and is in sliding contact with the outer periphery of the wheel side tube 2.

  The cylindrical lubrication gap 3 formed between the upper bearing 30 and the lower bearing 31 is reduced when the front fork extends, and the upper and lower bearings 30 and 31 approach and contract. When compressing, the upper and lower bearings 30 and 31 are separated and expanded.

  The lubrication gap 3 communicates with the lower working fluid chamber R2 via a communication hole 2a formed in the wheel side tube 2.

  A damper body 4 that generates a predetermined damping force and a suspension spring S are accommodated in the shock absorber body located inside the vehicle body side tube 1 and the wheel side tube 2, and a thrust input from the road surface is input by the suspension spring S. The damper 4 absorbs the expansion and contraction motion of the front fork accompanying this absorption.

  The suspension spring S has a lower end supported by the rod guide 5 and an upper end fitted into a cylindrical upper spring receiver 13 held by the cap member 10 so that the front fork is always extended in the extending direction. Energize.

  In the present embodiment, the initial load applied to the suspension spring S can be arbitrarily adjusted by rotating the adjuster 10a attached to the cap member 10 and moving the upper spring receiver 13 up and down in the drawing. .

  The damper 4 includes a cylinder 40 standing at the axial center of the wheel-side tube 2, an annular rod guide 5 crowned on the head portion of the cylinder 40, a piston 41 slidably contacting the inner periphery of the cylinder 40, A rod 42 that protrudes and retracts into the cylinder 40 through the piston 41 while penetrating the rod guide 5 and a base member 43 provided at the bottom of the cylinder 40 are provided.

  The rod 42 has an upper end fixed to the cap member 10 and moves in the cylinder 40 together with the piston 41 in accordance with the expansion and contraction of the front fork. The cross-sectional area X of the rod 42 is as shown in FIG. Further, it is formed smaller than the cross-sectional area Y of the lubrication gap 3.

  As shown in FIG. 1, the rod guide 5 includes a guide portion 50 having an annular bearing 50 a that pivotally supports a rod 42 on the inner periphery, and a diameter-enlarged portion 51 having an outer periphery larger than the cylinder 40. , And a coupling portion 52 that is screwed into the inner periphery of the head portion of the cylinder 40, and is always disposed in the working fluid chamber R.

  The base member 43 is held at the upper end portion of the base rod 8 that stands on the shaft center portion of the bottom portion of the cylinder 40, and the base rod 8 is formed on the lower side of the base member 43 and has an inner periphery of the cylinder 40. In addition, a flange 80 is provided in close contact with each other through a seal 80 a, and a liquid chamber C is formed between the flange 80 and the base member 43.

  The cylinder 40 includes a through hole 40a formed between the base member 43 and the flange 80, and the liquid chamber C communicates with the lower working fluid chamber R2 through the through hole 40a.

  And the inside of the cylinder 40 formed between the rod guide 5 and the base member 43 is divided into two working chambers A and B by the piston 41, and these are the extension side working chamber A located on the rod 42 side and The pressure side working chamber B is located on the piston 41 side.

  That is, on the inner side of the cylinder 40, an extension side action chamber A formed between the rod guide 5 and the piston 41, a pressure side action chamber B formed between the piston 41 and the base member 43, and the base member A liquid chamber C is formed between 43 and the flange 80.

  The extension side working chamber A communicates with the compression side action chamber B via an extension side flow path (not shown) formed in the piston 41 and a pressure side flow path 41 a, and the pressure side action chamber B is connected to the base member 43. The fluid chamber C communicates with the formed extension passage (not shown) and the pressure passage 43a, and the fluid chamber C communicates with the lower working fluid chamber R2 through the through hole 40a.

  An unillustrated expansion side flow path formed in the piston 41 is closed by an expansion side damping valve V1 stacked on the pressure side working chamber B side of the piston 41 so that it can be opened and closed. The flow path 41a is closed so as to be openable and closable by a pressure side check valve C2 stacked on the extension side working chamber A side of the piston 41.

  On the other hand, an unillustrated extension-side flow path formed in the base member 43 is closed by an extension-side check valve C1 stacked on the pressure-side action chamber B side of the base member 43 so that it can be opened and closed. The pressure-side flow path 43 a formed in the base is closed so as to be opened and closed by a pressure-side damping valve V <b> 2 stacked on the liquid chamber C side of the base member 43.

  In this embodiment, the base rod 8 is provided with a flange portion 80, an air chamber D is formed below the flange portion 80, and the working fluid stored in the front fork is reduced to reduce the weight of the front fork. However, the air chamber D is not necessarily provided.

  Further, in the present embodiment, the valve opening pressure of the pressure side check valve C2 provided in the piston 41 can be adjusted via an adjuster 10b attached to the cap member 10.

  The reservoir chamber formed between the damper 4 and the shock absorber main body is formed below the liquid level O and the air chamber G formed above the liquid level O of the working fluid stored inside. The working fluid chamber R is divided into upper and lower portions (R1, R2) by the enlarged diameter portion 51 of the rod guide 5.

  As shown in FIG. 2, an annular groove 7 having a U-shaped cross section is formed on the outer periphery of the center of the enlarged diameter portion 51, and a gap 51 a is formed between the upper and lower outer circumferences of the enlarged diameter portion 51 and the wheel side tube 2. , 51b are formed.

  The annular groove 7 is formed by loosely fitting an annular check valve 6 on the outer periphery, a vertical surface 70 facing the inner periphery of the check valve 6, and an upper surface formed opposite to the vertical surface 70. 71 and a lower surface 72.

  The check valve 6 has an axial length shorter than that of the vertical surface 70 and has a notch 60 formed in the radial direction on the lower surface thereof, and the outer periphery thereof slides on the inner periphery of the wheel side tube 2. A clearance channel 61 is formed between the inner periphery and the vertical surface 70.

  When the internal pressure of the upper working fluid chamber R1 becomes higher than the internal pressure of the lower working fluid chamber R2, the check valve 6 comes into contact with the lower surface 72 of the annular groove 7, and the clearance 51a and the upper surface of the check valve 6 are annularly connected. The working fluid can move through a gap (not shown) formed between the upper surface 71 of the groove 7, the gap channel 61, the notch 60, and the gap 51 b.

  In other words, the gap L, the gap formed between the upper surface of the check valve 6 and the upper surface 71 of the annular groove 7, the gap channel 61, the notch 60, and the gap 51b constitute the flow path L.

  On the other hand, when the internal pressure of the lower working fluid chamber R2 becomes higher than the internal pressure of the upper working fluid chamber R1, the check valve 6 is seated on the upper surface 71 of the annular groove 7, and the upper surface of the check valve 6 and the annular groove 7 There is no gap formed between the upper surface 71 and communication of the flow path L is prevented.

  Note that the check valve 6 can have only the movement of the working fluid from the upper working fluid chamber R1 to the lower working fluid chamber R2 by providing the above-described configuration. Is not limited to the above, and can be appropriately selected.

  The partition member that divides the working fluid chamber R into the upper and lower sides (R 1, R 2) is composed of the rod guide 5 having the enlarged diameter portion 51, and the flow path L is formed between the outer circumference of the enlarged diameter portion 51 and the wheel side tube 2. Therefore, processing for forming the flow path L is easy, but the configuration of the flow path L is not limited to the above, and a configuration can be appropriately selected.

  For example, although not shown, a partition wall is formed by bringing the outer periphery of the enlarged diameter portion 51 of the rod guide 5 into close contact with the inner periphery of the wheel side tube, and a hole penetrating in the axial direction is formed in the partition wall. May function as the flow path L.

  Next, the operation of the front fork as a shock absorber in the present embodiment will be described.

  When the front fork is extended, the extension side working chamber A is pressurized, the working fluid in the extension side working chamber A opens the extension side damping valve V1 of the piston 41 and moves to the compression side action chamber B, and the rod 42 that has retreated. The working fluid whose volume is insufficient opens the extension side check valve C1 of the base member 43 and moves from the lower working fluid chamber R2 to the pressure side working chamber B, and an extension side damping force is generated.

  As shown in FIG. 3, since the cross-sectional area Y of the lubrication gap 3 is smaller than the cross-sectional area X of the rod 42, the volume of the reduced lubrication gap 3 is smaller than the volume of the retracted rod 42.

  Accordingly, the working fluid corresponding to this difference is insufficient in the lower working fluid chamber R2, the internal pressure of the upper working fluid chamber R1 becomes higher than the internal pressure of the lower working fluid chamber R2, and the rod guide 5 is checked. Since the valve 6 is opened, the insufficient working fluid is supplemented from the upper working fluid chamber R1 to the lower working fluid chamber R2 via the flow path L (FIG. 3A).

  On the other hand, when the front fork is compressed, the pressure side working chamber B is pressurized, the working fluid in the pressure side working chamber B opens the pressure side check valve C2 of the piston 41 and moves to the extension side working chamber A, and The working fluid that is in excess of the volume integral opens the pressure side damping valve V2 of the base member 43 and moves from the pressure side working chamber B to the lower working fluid chamber R2, and a pressure side damping force is generated.

  Then, due to the difference between the cross-sectional areas X and Y of the rod 42 and the lubrication gap 3 (X> Y), the volume of the rod 42 that has entered is larger than the volume of the lubrication gap 3 that is enlarged.

  Accordingly, the working fluid corresponding to this difference becomes surplus in the lower working fluid chamber R2, and the internal pressure of the lower working fluid chamber R2 becomes higher than the internal pressure of the upper working fluid chamber R1, so that the rod guide 5 The check valve 6 is kept closed. As a result, the excess working fluid overflows from the lubrication gap 3 and passes between the upper bearing 30 and the vehicle body side tube 1, that is, through the sliding surface of the upper bearing 30, and thus the upper working fluid chamber. Move to R1 (FIG. 3B).

  That is, in the present embodiment, the working fluid always passes through the sliding surface of the upper bearing 30 when the front fork is compressed, so that the sliding surface of the upper bearing 30 can be reliably lubricated.

  In addition, the structure for this is simpler than in the prior art, and the front fork is not complicated.

  Next, an embodiment of the present invention will be described. The shock absorber according to the present embodiment is embodied in the front fork as in the above-described reference embodiment, and as shown in FIG. 4 which is the principle diagram, the cross-sectional area Y of the lubrication gap 3 is larger than the cross-sectional area X of the rod The configuration is different from the reference embodiment only in that is formed large, and the other configurations are the same as the reference embodiment.

  Therefore, the detailed configuration of the front fork in the present embodiment will be described with reference to a reference form, and the operation of the front fork in the present embodiment and the effects due to the difference in the above configuration will be described below.

  In the present embodiment, when the front fork is extended, the extension side working chamber A is pressurized and the working fluid in the extension side action chamber A opens the extension side damping valve V1 of the piston 41 when the front fork is extended. The working fluid which moves to the pressure side working chamber B and the rod 42 whose volume is insufficient opens the extension side check valve C1 of the base member 43, moves from the lower working fluid chamber R2 to the pressure side working chamber B, and extends. Side damping force is generated.

  In the present embodiment, as shown in FIG. 4, since the cross-sectional area of the lubricating gap Y is larger than the cross-sectional area X of the rod 42, the volume of the reduced lubricating gap is larger than the volume of the retracted rod 42. Become.

  Accordingly, the working fluid corresponding to this difference becomes surplus in the lower working fluid chamber R2, and the internal pressure of the lower working fluid chamber R2 becomes higher than the internal pressure of the upper working fluid chamber R1, so that the rod guide 5 The check valve 6 is kept closed. As a result, the excess working fluid overflows from the lubrication gap 3 and passes between the upper bearing 30 and the vehicle body side tube 1, that is, through the sliding surface of the upper bearing 30, and thus the upper working fluid chamber. Move to R1 (FIG. 4A).

  On the other hand, when the front fork is compressed, the pressure side working chamber B is pressurized, and the working fluid in the pressure side working chamber B opens the pressure side check valve C2 of the piston 41 and moves to the expansion side working chamber A as in the reference embodiment. Then, the working fluid, which is the surplus volume of the rod 42 that has entered, opens the pressure side damping valve V2 of the base member 43 and moves from the pressure side working chamber B to the lower working fluid chamber R2, and a pressure side damping force is generated. .

  In this embodiment, due to the difference between the cross-sectional areas X and Y of the rod 42 and the lubrication gap 3 (X <Y), the volume of the entering rod 42 is smaller than the volume of the lubrication gap 3 that is enlarged. .

  Accordingly, the working fluid corresponding to this difference is insufficient in the lower working fluid chamber R2, the internal pressure of the upper working fluid chamber R1 becomes higher than the internal pressure of the lower working fluid chamber R2, and the rod guide 5 is checked. Since the valve 6 is opened, the insufficient working fluid is supplemented from the upper working fluid chamber R1 to the lower working fluid chamber R2 via the flow path L (FIG. 4B).

  That is, in the present embodiment, the working fluid always passes through the sliding surface of the upper bearing 30 when the front fork is extended, so that the sliding surface of the upper bearing 30 can be reliably lubricated.

  In addition, the structure for this is simpler than in the prior art, and the front fork is not complicated.

  Further, in the present embodiment, when the front fork is extended, a resistance is generated when the working fluid in the lubricating gap 3 passes between the upper bearing 30 and the vehicle body side tube 1, and an extension side damping force is generated. .

  Accordingly, the damping force generated when the front fork is extended can be increased, and the ride comfort of the vehicle can be improved compared to the reference embodiment in which the damping force is increased when the front fork is compressed.

  Although preferred embodiments of the present invention have been described in detail above, it should be understood that modifications, variations and changes may be made without departing from the scope of the claims.

  For example, in the above-described embodiment, the present invention is embodied in the front fork. However, the present invention is not limited thereto, and may be embodied in a rear cushion unit or other shock absorber.

A Stretch-side working chamber B Pressure-side working chamber G Air chamber C1 Stretch-side check valve C2 Pressure-side check valve L Flow path R Working fluid chamber R1 Upper working fluid chamber R2 Lower working fluid chamber V1 Stretch-side damping valve V2 Pressure-side damping valve DESCRIPTION OF SYMBOLS 1 Vehicle body side tube 2 Wheel side tube 2a Communication hole 3 Lubrication clearance 4 Damper 5 Rod guide 6 Check valve 7 Annular groove 10 Cap member 20 Bottom member 30 Upper bearing 31 Lower bearing 40 Cylinder 40a Through hole 41 Piston 42 Rod 43 Base member 50 Guide portion 51 Expanded diameter portion 52 Coupling portion 60 Notch 61 Gap channel

Claims (5)

It comprises a vehicle body side tube and a wheel side tube that is slidably inserted into the vehicle body side tube via a pair of upper and lower bearings. The upper bearing is on the outer periphery of the wheel side tube and the lower bearing is on the vehicle body side. A shock absorber body attached to the inner periphery of the tube and having a lubrication gap formed between these bearings;
A cylinder that stands up at the axial center of the wheel side tube and accommodates the working fluid; a piston that slidably contacts the inner periphery of the cylinder and divides the cylinder into two working chambers; A damper having a rod that appears and disappears in,
In the shock absorber comprising an air chamber and a working fluid chamber formed between the shock absorber main body and the damper, and a reservoir chamber for supplementing the working fluid that is excessive or insufficient in the damper,
A partition member that divides the working fluid chamber up and down, and a flow path that includes a check valve that is formed in the partition member and allows only the movement of the working fluid from the upper working fluid chamber to the lower working fluid chamber; A communication path communicating the lower working fluid chamber and the lubrication gap,
A shock absorber characterized in that the working fluid is prevented from moving from the lower working fluid chamber to the upper working fluid, and the cross-sectional area of the lubricating gap is larger than the cross-sectional area of the rod. The working chamber defined by the piston is an extension working chamber formed on the rod side and a pressure working chamber formed on the piston side,
2. The shock absorber according to claim 1, wherein a base member is provided at a bottom portion of the cylinder, and the pressure side working chamber communicates with the lower working fluid chamber via the base member.   The shock absorber according to claim 1 or 2, wherein the partition member is an annular rod guide that is attached to a head portion of the cylinder.   The rod guide includes an enlarged diameter portion having an outer diameter larger than that of the cylinder, and the flow path is formed between the outer circumference of the enlarged diameter portion and the wheel side tube. The shock absorber according to claim 3. An annular groove having a U-shaped cross section is formed on the outer periphery of the expanded diameter portion, and the annular check valve is loosely fitted on the outer periphery of the annular groove
The annular groove is composed of a vertical surface facing the inner periphery of the check valve, and an upper surface and a lower surface formed opposite to each other above and below the vertical surface,
The check valve is formed to have a shorter axial length than the vertical surface, the outer periphery is in sliding contact with the inner periphery of the wheel side tube, and has a notch formed in the radial direction on the lower surface of the check valve. 5. The shock absorber according to claim 4, wherein a gap channel is formed between an inner periphery of the check valve and the vertical surface.

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