JP4965490B2 - Hydraulic shock absorber - Google Patents

Description

  The present invention relates to a hydraulic shock absorber.

  Conventionally, as a hydraulic shock absorber, as described in Patent Document 1, an inner tube on the axle side is slidably inserted into an outer tube on the vehicle body side, and a partition member is provided on the inner tube. A hydraulic oil chamber is defined inside the lower inner tube, an oil reservoir chamber is defined in the upper portion, and a piston rod attached to the outer tube side is inserted into the hydraulic oil chamber through the partition wall of the partition member, and the piston A piston that slides in the hydraulic oil chamber is provided at the tip of the rod, and an annular oil chamber is defined between the inner periphery of the outer tube and the outer periphery of the inner tube, and this annular oil chamber is provided in the inner tube. It communicates with the hydraulic oil chamber through a hole, the interior of the hydraulic oil chamber is partitioned into a piston-side oil chamber and a rod-side oil chamber by a piston, and is extended to a flow path connecting the piston-side oil chamber and the rod-side oil chamber of the piston. Side damping valve and compression side damping bar There are things to be provided with the drive.

  In the hydraulic shock absorber described in Patent Document 1, the volume of the annular oil chamber changes as the hydraulic shock absorber expands and contracts, and when compressed, the annular oil chamber expands to compress the hydraulic oil that enters the oil chamber of the piston rod into the piston. Absorbs from the rod side oil chamber through the oil hole of the inner tube, and when it is extended, it contracts and replenishes the hydraulic oil that has retreated from the oil chamber of the piston rod to the piston rod side oil chamber through the oil hole of the inner tube. The volume compensation chamber for the entrance / exit of the piston rod is configured. At this time, in order to avoid the difficulty of dimensional control of each member in which the sectional area S1 of the annular oil chamber formed by the annular gap between the outer tube and the inner tube and the sectional area S2 of the piston rod are S1 = S2, S1> S2 In addition, a shortage of oil replenishment (ΔS1−ΔS2) from the hydraulic oil chamber of the inner tube to the annular oil chamber due to ΔS1> ΔS2 in the compression stroke is supplied from the oil reservoir chamber to the hydraulic oil chamber. A check valve is provided on the partition member. Further, a minute flow path for discharging the excess oil discharge amount (ΔS1−ΔS2) from the annular oil chamber to the hydraulic oil chamber resulting from ΔS1> ΔS2 in the extension side stroke from the hydraulic oil chamber to the oil reservoir chamber. Is provided on the partition member.

According to such a hydraulic shock absorber described in Patent Document 1, the hydraulic oil chamber into which the piston rod is inserted is formed by an inner tube, and is not formed by a damper cylinder provided in the inner tube. Can be simplified. In addition, the outer diameter of the piston that slides in the hydraulic oil chamber can be set to a large diameter that is the same as the inner diameter of the inner tube, and the pressure in the hydraulic oil chamber can be reduced, thereby suppressing variations in the damping force generated by the damping valve. Can do.
JP2003-269515

  In the hydraulic shock absorber described in Patent Document 1, in order to compensate the volume of the piston rod entering / leaving into / from the hydraulic oil chamber in the inner tube, the partition member is provided with a check valve and a micro flow path, and an oil reservoir chamber And movement of oil between the hydraulic oil chamber is required. For this reason, bubbles are likely to be mixed into the oil in the hydraulic oil chamber, which may cause the damping force to become unstable.

  In addition, it is difficult to set the mutual relationship between the degree of restriction of the micro flow path provided in the partition wall member and the degree of restriction of the expansion side damping valve provided in the piston. If the throttle degree of the micro flow path is weaker than the throttle degree of the expansion side damping valve, the oil in the rod side oil chamber easily flows to the oil reservoir chamber through the micro flow path, and the extension side damping valve opens to the piston side oil chamber. Since the amount of flowing oil is reduced, the extension side damping force becomes insufficient and unstable, and when the reversal from the extension side stroke to the compression side stroke occurs, the piston rod moves freely and the compression side damping force becomes insufficient and unstable. .

  An object of the present invention is to stabilize a damping force in a hydraulic shock absorber in which a piston provided on a piston rod attached to an outer tube slides in a hydraulic oil chamber inside the inner tube.

According to the first aspect of the present invention, the inner tube on the axle side is slidably inserted into the outer tube on the vehicle body side, and upper and lower partition members are provided at two upper and lower positions along the axial direction in the inner tube. A hydraulic oil chamber is defined between the upper partition member and an oil reservoir chamber, and a piston rod attached to the outer tube side is inserted through the upper and lower partition members and inserted into the hydraulic oil chamber in the inner tube. A piston that slides the hydraulic oil chamber in the inner tube is provided in the middle part of the piston rod sandwiched between the upper and lower partition members, and the hydraulic oil chamber in the inner tube is divided into upper and lower oil chambers by the piston, a hydraulic shock absorber in a flow path communicating the oil chamber formed by providing a damping force generating section, on said partition wall member, and communicating the oil reservoir chamber and the upper oil chamber, the oil in the operating oil chamber of the inner tube temperature compensation for the fine flow for It is obtained by the so provided.

According to a second aspect of the present invention, in the first aspect of the present invention, the upper partition member is further provided with a temperature compensating check valve that allows oil to flow from the oil reservoir chamber to the upper oil chamber. .

According to a third aspect of the present invention, in the first or second aspect of the present invention, an annular oil chamber is defined between the inner periphery of the outer tube and the outer periphery of the inner tube, and the annular oil chamber is provided in the inner tube. It communicates with the oil reservoir through an oil hole .

(Claim 1)
(a) The piston rod attached to the outer tube side is inserted into the hydraulic oil chamber in the inner tube through the upper and lower partition members, and the hydraulic oil in the inner tube is inserted in the middle of the piston rod sandwiched between the upper and lower partition members. A piston sliding through the chamber was provided. Therefore, when the hydraulic shock absorber expands and contracts, the piston rod that enters / withdraws into the hydraulic oil chamber in the inner tube becomes a double rod type, and there is no need to perform volume compensation for the entry / exit of the piston rod. Therefore, it is not necessary to provide the partition member with a check valve or a minute flow path that serves as a volume compensation flow path for the piston rod or a flow volume for fine adjustment of the volume compensation, and the oil for volume compensation is supplied to the hydraulic oil chamber and the oil reservoir. There is no need to move between rooms. Therefore, air bubbles are not mixed in the oil in the hydraulic oil chamber, the throttle degree of the damping valve provided on the piston can be easily set, and the damping force can be stabilized.

(b) The upper partition member is provided with a temperature compensating micro-channel that communicates between the oil reservoir and the upper oil chamber. Accordingly, the temperature expansion of the oil in the hydraulic oil chamber in the inner tube is discharged from the hydraulic oil chamber through the minute channel to the oil reservoir chamber, and the temperature is compensated.

(Claim 2)
(c) The upper partition member is provided with a temperature compensating check valve that allows oil to flow from the oil reservoir to the upper oil chamber. Accordingly, the temperature contraction of the oil in the hydraulic oil chamber in the inner tube is immediately drawn into the hydraulic oil chamber from the oil reservoir chamber through the check valve, and the temperature is compensated.

(Claim 3 )
(d) The annular oil chamber between the inner periphery of the outer tube and the outer periphery of the inner tube is used as a lubricating oil chamber that always communicates with the oil reservoir chamber through the oil hole of the inner tube, and sliding on the tip side of the inner tube And the sliding portion on the open end side of the outer tube can be lubricated. This annular oil chamber (lubricating oil chamber) communicates directly with the oil reservoir chamber and does not contribute to the volume of the hydraulic oil chamber.

  1 is an overall sectional view showing a hydraulic shock absorber, FIG. 2 is an enlarged view of FIG. 1, FIG. 3 is an enlarged view of a lower part of FIG. 2, FIG. 4 is an enlarged view of an upper part of FIG. FIG. 6 is a cross-sectional view showing a damping force adjusting structure.

  The front fork (hydraulic shock absorber) 10 is an inverted front fork in which the outer tube 11 is disposed on the vehicle body side and the inner tube 12 is disposed on the wheel side. As shown in FIGS. The inner tube 12 is slidably inserted into the outer tube 11 through a guide bush 11A fixed to the inner periphery of the inner tube 12 and a guide bush 12A fixed to the outer periphery of the upper end opening of the inner tube 12. 11B is an oil seal, and 11C is a dust seal. A cap 13 is screwed and sealed to the upper end opening of the outer tube 11 in a liquid-tight manner, and a vehicle body side mounting member is provided on the outer periphery of the outer tube 11. An axle bracket 15 is liquid-tightly inserted and screwed into the lower end opening of the inner tube 12 to form the bottom of the inner tube 12, and the axle bracket 15 is provided with an axle mounting hole 15A.

  The front fork 10 defines an inner periphery of the outer tube 11, an outer periphery of the inner tube 12, and an annular oil chamber 16 defined by the two guide bushes 11A and 12A.

  The front fork 10 is provided with upper and lower partition members 17 and 18 at two upper and lower positions along the axial direction in the inner tube 12. The upper partition wall member 17 has a bottomed cylindrical upper end outer peripheral portion screwed to the upper end inner peripheral portion of the inner tube 12, and is attached to the inner periphery of the inner tube 12, and its bottom portion is defined as a rod guide portion 17A. The rod guide portion 17A is liquid-tightly sealed on the inner periphery of the inner tube 12 via an O-ring 17B. The lower partition wall member 18 is screwed onto the inner peripheral portion of the upper end of a support cylinder 19 that is sandwiched between the lower end portion of the inner tube 12 and the bottom portion of the axle bracket 15 and attached to the inner periphery of the inner tube 12. Part 18A is configured. The rod guide portion 18A is liquid-tightly sealed on the inner periphery of the inner tube 12 via an O-ring 18B.

  The front fork 10 divides a hydraulic oil chamber 21 between the rod guide portions 17A and 18A of the upper and lower partition wall members 17 and 18 inside the inner tube 12, and oil is placed above the rod guide portion 17A of the upper partition wall member 17. The reservoir chamber 22 is partitioned. In the oil reservoir 22, the lower region is an oil chamber 22A, and the upper region is an air chamber 22B.

  The front fork 10 passes the piston rod 23 attached to the outer tube 11 side through the rod guide portions 17A and 18A of the upper and lower partition wall members 17 and 18 and inserts them into the hydraulic oil chamber 21 in the inner tube 12 to move the upper and lower A piston 26 that slides in the hydraulic oil chamber 21 in the inner tube 12 is provided at an intermediate portion of the piston rod 23 sandwiched between the rod guide portions 17A and 18A. Specifically, the piston rod 23 is composed of upper and lower rods 23A and 23B having the same cross section (same diameter). Then, the upper rod 23A is screwed to the mounting collar 24 screwed to the lower end portion of the center portion of the cap 13, and this is fixed by the lock nut 24A. Further, the upper end portion of the piston bolt 25 is screwed to the tip portion of the upper rod 23A inserted into the hydraulic oil chamber 21 through the bush 17C provided in the rod guide portion 17A of the upper partition member 17, and the piston bolt 25 is connected to the piston portion 25 at the intermediate portion thereof. 26 is inserted and fixed, and the lower rod 23B is screwed and fixed to the lower end of the piston bolt 25. The lower rod 23B enters the air chamber 27 below the lower partition wall member 18 through the oil seal 18C and the bush 18D provided in the rod guide portion 18A of the lower partition wall member 18. Although the air chamber 27 is formed by dividing the axle bracket 15 and the lower partition wall member 18 inside the inner tube 12 in this embodiment, it may be opened to the external space. However, even if the air chamber 27 is closed with respect to the external space, the lower rod 23 </ b> B does not interfere with the expansion / contraction of the front fork 10 due to the volume change of the compressible air.

  The front fork 10 divides the hydraulic oil chamber 21 in the inner tube 12 into upper and lower oil chambers 21A and 21B by a piston 26, and connects the upper and lower oil chambers 21A and 21B provided in the piston 26 (pressure side described later). A damping force generator (a pressure side disc valve 41A and an extension side disc valve 42A described later) is provided in the flow channel 41 and the extension side flow channel 42). The upper oil chamber 21A accommodates the upper rod 23A, and the lower oil chamber 21B accommodates the lower rod 23B.

  The front fork 10 connects the annular oil chamber 16 to the oil chamber 22 </ b> A of the oil reservoir chamber 22 through an oil hole 28 provided in the inner tube 12 and an oil hole 29 provided in the rod guide portion 17 </ b> A of the upper partition wall member 17. Always communicate. The annular oil chamber 16 serves as a lubricating oil chamber for the guide bushes 11 </ b> A and 12 </ b> A of the outer tube 11 and the inner tube 12.

  The front fork 10 includes a main suspension spring between an upper spring receiver 31 attached to an attachment collar 24 screwed to the cap 13 and a lower spring receiver 32 supported on the upper surface of the rod guide portion 17A of the upper partition member 17. 33 is interposed. A flange of a spring collar 34 is sandwiched between the upper spring receiver 31 and the upper end of the main suspension spring 33, and the spring collar 34 is inserted into the outer periphery of the piston rod 23 to guide the inner diameter of the main suspension spring 33. . The front fork 10 absorbs the impact force received from the road surface when the vehicle travels by the expansion and contraction vibration of the main suspension spring 33.

The front fork 10 includes a damping force generator 40 on the piston 26 (FIGS. 3 and 4).
The damping force generator 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 (pressure side damping valve) backed up by a valve stopper 41B. The extension side flow path 42 is opened and closed by an extension side disk valve 42A (extension side damping valve) backed up by a valve stopper 42B. The valve stopper 41B, the valve 41A, the piston 26, the valve 42A, and the valve stopper 42B constitute a valve assembly that is inserted into the piston bolt 25, and are sandwiched between lower rods 23B that are screwed into the piston bolt 25. Fixed.

  The damping force generator 40 is provided with a damping force adjusting device 40A, which will be described in detail later, at the center of the cap 13, and the needle valve 85 of the damping force adjusting device 40A is inserted into the hollow portion of the piston rod 23 and provided on the piston rod 23. The opening degree of the bypass passage 45 is adjusted by the vertical movement of the needle valve 85. The bypass passage 45 is formed in the piston bolt 25 and the lower rod 23B, bypasses the piston 26, and connects the upper oil chamber 21A and the lower oil chamber 21B. A plug 46 seals the hollow portion of the lower rod 23B and partitions the bypass passage 45.

  In the compression side stroke in which the piston rod 23 (upper rod 23A) enters the inner tube 12, the damping force generator 40 generates the compression side damping force by the passage resistance of the bypass passage 45 whose opening is adjusted by the needle valve 85 in the low speed region. The pressure side damping force is generated by the bending deformation of the pressure side disk valve 41A in the middle and high speed range. Further, in the extension side stroke in which the piston rod 23 (upper rod 23A) retreats from the inner tube 12, 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 85 in the low speed region. In the middle and high speed range, the expansion side damping force is generated by the bending deformation of the expansion side disk valve 42A. This compression side damping force and extension side damping force control the expansion and contraction vibration of the main suspension spring 33 described above.

  The front fork 10 is provided with a stopper rubber 13A and a stopper plate 13B in which the upper end portion of the upper partition wall member 17 provided on the inner tube 12 abuts with the most compression stroke on the lower end surface of the cap 13, and the stopper rubber 13A Regulates the maximum compression stroke.

  The front fork 10 is provided on the piston rod 23 (upper rod 23A) and the spring seat 51 fixed to the lower end surface facing the upper oil chamber 21A of the upper partition member 17 on the upper end side of the inner tube 12 using a stopper ring 51A. A rebound spring 53 is interposed between the spring seat 52 locked to the stopper ring 52A. When the front fork 10 is fully extended, the upper partition member 17 presses the rebound spring 53 between the spring seat 52 and regulates the maximum extension stroke.

  In the front fork 10, a temperature compensating check valve 60 that allows oil to flow from the oil reservoir 22 to the upper oil chamber 21 </ b> A is provided in the rod guide portion 17 </ b> A and the spring seat 51 of the upper partition member 17. . A valve spring 60A is interposed between the lower surface of the check valve 60 and the upper surface of the spring seat 51 to position the check valve 60 in the closed position. Further, the above-described bush 17C press-fitted into the inner periphery of the check valve 60 is used for temperature compensation for communicating the oil reservoir chamber 22 and the upper oil chamber 21A by a minute gap formed around the piston rod 23 (upper rod 23A). A minute flow path (orifice) 61 (not shown) is formed.

Hereinafter, the damping force adjusting device 40A will be described.
As shown in FIGS. 3 and 4, the damping force adjusting device 40A inserts two push rods 71 and 72 concentrically inserted into the hollow portion of the piston rod 23 (the push rod 72 is inserted into the hollow portion of the piston rod 23). The push rod 71 is inserted into the hollow portion of the push rod 72), the first adjustment portion 80 for moving the push rod 71 in the axial direction, and the second adjustment portion 90 for moving the push rod 72 in the axial direction. It is provided on the cap 13 which is the upper part of the fork 10.

  The first adjustment unit 80 adjusts the damping force due to the passage resistance of the bypass passage 45 by moving the needle valve 85. The second adjustment unit 90 adjusts the set force of the spring 97 that urges the compression-side disc valve 41A in the closing direction to adjust the damping force due to the deflection deformation of the compression-side disc valve 41A. Hereinafter, the structure of the first adjusting unit 80 and the second adjusting unit 90, the damping force adjusting structure using the needle valve 85, and the damping force adjusting structure using the spring 97 will be described.

(Structure of the 1st adjustment part 80 and the 2nd adjustment part 90) (FIGS. 3-6)
An attachment collar 24 is screwed to the lower end opening side of the cap 13 to constitute the cap assembly 100. The cap 13 of the cap assembly 100 is thread-tightly screwed to the upper end opening of the outer tube 11 via the O-ring 101, and the upper end of the piston rod 23 is screwed to the lower end of the mounting collar 24 to lock nut 24A. It is fixed with. A stopper rubber 13A is loaded in an annular recess formed by the cap 13 and the mounting collar 24 of the cap assembly 100, and a stopper plate 13B is inserted into the outer periphery of the mounting collar 24, and the stopper plate 13B is locked. A stopper ring 13C is engaged.

  The adjustment assembly 110 is loaded on the cap 13 and the mounting collar 24 of the cap assembly 100. In the adjustment assembly 110, the first adjustment portion 80 is configured by the first adjustment bolt 81, the second adjustment portion 90 is configured by the second adjustment bolt 91, and the first and second adjustment bolts 81 and 91 correspond to the first and second adjustment bolts 91, 91, respectively. Second adjustment nuts 82 and 92 are provided. The first adjustment nut 82 includes a screw hole 82A into which the screw portion 81A of the corresponding first adjustment bolt 81 is screwed, and a guide hole 82B into which the guide portion 91B of the other adjustment bolt 91 is inserted. The second adjustment nut 92 includes a screw hole 92A into which the screw portion 91A of the corresponding second adjustment bolt 91 is screwed, and a guide hole 92B into which a guide collar 81B fitted to another adjustment bolt 81 is inserted. Accordingly, the first adjusting nut 82 into which the adjusting bolt 81 is screwed by the rotation operation of the first adjusting bolt 81 is related to the guide hole 82B of the adjusting nut 82 and the guide portion 91B of the other adjusting bolt 91. Through rotation, it is prevented from rotating and guided in movement in the axial direction, and moves up and down in the axial direction. On the other hand, when the second adjusting bolt 91 is rotated, the second adjusting nut 92 into which the adjusting bolt 91 is screwed is engaged with the guide hole 92B of the adjusting nut 92 and the guide collar 81B of the other adjusting bolt 81. Through rotation, it is prevented from rotating and guided in movement in the axial direction, and moves up and down in the axial direction.

  The first adjustment bolt 81 of the first adjustment portion 80 constituting the adjustment assembly 110 and the second adjustment bolt 91 of the second adjustment portion 90 are the center of the cap 13 in a plan view of the cap 13 constituting the cap assembly 100. From the back side of the cap 13, the two loading holes juxtaposed at positions away from each other are inserted in a liquid-tight manner via O-rings 83 and 93. The first adjustment bolt 81 and the second adjustment bolt 91 are accommodated in the central recess 102 of the cap assembly 100 formed by screwing the mounting collar 24 onto the cap 13 together with the adjustment nuts 82 and 92, and the adjustment bolt 81, The flange portions 81 </ b> C and 91 </ b> C of 91 are brought into contact with the lower surface of the cap 13, and the lower end surfaces of the adjusting bolts 81 and 91 are brought close to the bottom surface of the central recess 102 formed by the mounting collar 24. The adjusting nuts 82 and 92 are accommodated in the inner periphery of the central recess 102 formed by the mounting collar 24 so as to be slidable. The push rod 71 protruding from the hollow portion of the piston rod 23 and the push rod 72 passes through the center hole 92C of the second adjustment nut 92 and is abutted against the lower end surface of the first adjustment nut 82, and the hollow portion of the piston rod 23 The push rod 72 protruding from the center of the second adjustment nut 92 is abutted against the lower end surface of the second adjustment nut 92 around the center hole 92C.

  As a result, the upper end operation portion 80A of the first adjustment bolt 81 of the first adjustment portion 80 and the upper end operation portion 90A of the second adjustment bolt 91 of the second adjustment portion 90 are the planes of the cap 13 constituting the cap assembly 100. They are juxtaposed with each other at a level that is flush with the upper surface of the cap 13 at a position deviating from the center of the cap 13. The first adjustment bolt 81 of the first adjustment unit 80 is pivotally supported by the cap 13 so as not to rotate but move in the axial direction, and the second adjustment bolt 91 of the second adjustment unit 90 is also only rotated by the cap 13. Thus, it is pivotally supported so as not to move in the axial direction. Accordingly, when the first adjustment bolt 81 of the first adjustment unit 80 is rotated, the first adjustment nut 82 into which the first adjustment bolt 81 is screwed moves up and down in the axial direction, and the first adjustment nut 82 is moved. It is possible to move the push rod 71 abutted on the shaft in the axial direction. On the other hand, when the second adjustment bolt 91 of the second adjustment portion 90 is rotated, the second adjustment nut 92 with which the second adjustment bolt 91 is screwed moves up and down in the axial direction, and the second adjustment nut 92 is moved. It is possible to move the push rod 72 abutted against the shaft in the axial direction.

(Damping force adjustment structure using needle valve 85) (FIGS. 3 and 6)
An inner base 84 is inserted into the lower end portion of the hollow portion of the piston rod 23, and the lower end surface of the piston rod 23 and the inner diameter step portion of the piston bolt 25 clamp and fix the lower end flange of the inner base 84. The inner base 84 may be press-fitted into the hollow portion of the piston rod 23. In this manner, the needle valve 85 is liquid-tightly inserted into the inner periphery of the inner base 84 fixed to the piston rod 23, and is interposed between the intermediate flange portion 85A of the needle valve 85 and the upper end surface of the inner base 84. The spring 86 biases the needle valve 85 upward (in the valve opening direction) in the axial direction, and the upper end surface of the needle valve 85 abuts against the lower end surface of the push rod 71.

  As described above, when the first adjusting bolt 81 of the first adjusting unit 80 moves the push rod 71 up and down in the axial direction, the needle valve 85 that abuts the push rod 71 in the axial direction is moved against the piston bolt 25. The valve moves up and down with respect to the valve seat at the upper end of the vertical hole of the bypass passage 45 provided in the piston bolt 25, adjusts the opening degree of the bypass passage 45, and as a result, expands and contracts due to the passage resistance of the bypass passage 45 The damping force on the side can be adjusted.

(Damping force adjustment structure using spring 97) (FIGS. 3 and 6)
On both sides in the diametrical direction on the lower end side of the piston rod 23 (upper rod 23A), elongated hole-shaped guide holes 94A extending in the axial direction are provided. Instead, it is slidably inserted in the axial direction. The lower end surface of the push rod 72 inserted into the hollow portion of the piston rod 23 directly contacts the upper surface of the push piece 94, and the cross section of the needle valve 85 that is loosely inserted into the lower end portion of the push rod 72 is pressed. It is loosely inserted in a circular hole provided in the center of the moving piece 94 so as to be axially movable.

  Around the lower end portion (piston bolt 25) of the piston rod 23, there are a spring receiver 95 that abuts against the protrusions on both ends of the pushing piece 94 from below, and a valve retainer 96 that abuts against the upper surface (rear surface) of the pressure side disk valve 41A. The valve retainer spring 97 is interposed between the spring receiver 95 and the valve retainer 96. The spring receiver 95 has a cup shape and abuts with both side protrusions of the pushing piece 94 at the lower end of the inner periphery of the cup, and the spring 97 is seated on the upper peripheral flange of the cup. The valve presser 96 is a slide that is slidably guided on the outer periphery of the upper end of the piston bolt 25, and an annular presser part 96A that continuously contacts the entire circumference (or intermittently) at an appropriate outer diameter position on the upper surface of the compression side disk valve 41A. An oil passage 96C that communicates the portion 96B with the upper oil chamber 21A to the pressure side passage 41, the extension side passage 42, and the bypass passage 45 is provided, and a spring 97 is seated on the outer circumferential step portion.

  As described above, when the adjusting bolt 91 of the second adjusting unit 90 moves the push rod 72 in the axial direction, the pushing piece 94 with which the lower end surface of the push rod 72 abuts moves the spring receiver 95 up and down. The valve presser spring 97 is expanded and contracted, and the set load of the spring 97 is adjusted. As a result, the set load of the spring 97 biases the pressure side disk valve 41A in the closing direction via the valve presser 96, and the pressure side damping force due to the bending deformation of the pressure side disk valve 41A can be adjusted. The valve presser 96 can be replaced with one having a different diameter of the presser part 96A. The valve presser 96 provided with the large-diameter presser part 96A presses the outer peripheral side of the pressure side disk valve 41A, and from the low speed range of the piston speed. Increase the damping force. A valve presser 96 provided with a small-diameter presser part 96A presses the inner peripheral side of the pressure side disc valve 41A, and increases the damping force in the middle to high speed range of the piston speed.

Therefore, according to the present embodiment, the following operational effects can be obtained.
(a) The piston rod 23 attached to the outer tube 11 side is inserted into the hydraulic oil chamber 21 in the inner tube 12 through the upper and lower partition members 17 and 18, and is sandwiched between the upper and lower partition members 17 and 18. A piston 26 that slides in the hydraulic oil chamber 21 in the inner tube 12 is provided at an intermediate portion of the inner tube 23. Accordingly, when the front fork 10 expands and contracts, the piston rod 23 entering / exiting the hydraulic oil chamber 21 in the inner tube 12 becomes a double rod type, and it is necessary to compensate for the volume of the piston rod 23 entering / exiting. Absent. For this reason, there is no need to provide the partition member 17 with a check valve or a minute flow path that serves as a volume compensation flow path of the piston rod 23 or a volume compensation fine adjustment flow path, and oil for volume compensation is supplied to the hydraulic oil chamber 21. There is no need to move between the oil reservoir 22 and the oil reservoir 22. Therefore, air bubbles are not mixed into the oil in the hydraulic oil chamber 21, the throttle degree of the compression side disk valve 41A and the extension side disk valve 42A provided in the piston 26 can be easily set, and the damping force can be stabilized. Can do.

  (b) The upper partition wall member 17 is provided with a micro flow channel 61 that communicates between the oil reservoir 22 and the upper oil chamber 21A. Therefore, the temperature expansion of the oil in the hydraulic oil chamber 21 in the inner tube 12 is discharged from the hydraulic oil chamber 21 through the minute flow path 61 to the oil reservoir chamber 22 and temperature compensated.

  (c) The upper partition member 17 is provided with a check valve 60 that allows oil to flow from the oil reservoir chamber 22 to the upper oil chamber 21A. Accordingly, the temperature contraction of the oil in the hydraulic oil chamber 21 in the inner tube 12 is immediately drawn into the hydraulic oil chamber 21 from the oil reservoir chamber 22 through the check valve 60, and the temperature is compensated.

  (d) The annular oil chamber 16 between the inner periphery of the outer tube 11 and the outer periphery of the inner tube 12 is used as a lubricating oil chamber that always communicates with the oil reservoir chamber 22 through the oil hole 28 of the inner tube 12, and the inner tube The sliding portion (guide bush 12A) on the distal end side of 12 and the sliding portion (guide bush 11A) on the open end side of the outer tube 11 can be lubricated. The annular oil chamber 16 (lubricating oil chamber) communicates directly with the oil reservoir chamber 22 and does not contribute to the volume of the hydraulic oil chamber 21.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention.

FIG. 1 is an overall cross-sectional view showing a hydraulic shock absorber. FIG. 2 is an enlarged view of FIG. FIG. 3 is an enlarged view of the lower part of FIG. 4 is an enlarged view of the upper part of FIG. FIG. 5 is a cross-sectional view showing an adjusting portion provided on the cap. FIG. 6 is a cross-sectional view showing the damping force adjusting structure.

Explanation of symbols

10 Front fork (hydraulic shock absorber)
11 outer tube 12 inner tube 16 annular oil chamber 17 upper partition member 18 lower partition member 21 working oil chamber 21A upper oil chamber 21B lower oil chamber 22 oil reservoir chamber 23 piston rod 23A upper rod 23B lower rod 26 piston 28 oil hole 41 pressure side Flow path 41A Pressure side disk valve (damping force generator)
42 Stretching side flow path 42A Stretching side disk valve (damping force generator)
60 Check valve (check valve)
61 Microchannel

Claims (3)

Insert the inner tube on the axle side slidably into the outer tube on the vehicle body side,
Upper and lower partition members are provided in two positions along the axial direction in the inner tube, a hydraulic oil chamber is defined between the upper and lower partition members, and an oil reservoir chamber is defined above the upper partition member,
The piston rod attached to the outer tube side is inserted into the hydraulic oil chamber in the inner tube through the upper and lower partition members, and the hydraulic oil chamber in the inner tube is slid between the piston rods sandwiched between the upper and lower partition members. A moving piston,
A hydraulic shock absorber in which a hydraulic oil chamber in the inner tube is divided into upper and lower oil chambers by a piston, and a damping force generation unit is provided in a flow path connecting the upper and lower oil chambers of the piston,
On said partition wall member, and communicating the oil reservoir chamber and the upper oil chamber, a hydraulic shock absorber comprising providing a temperature compensating fine channel for oil of the hydraulic oil chamber of the inner tube. 2. The hydraulic buffer according to claim 1, wherein the upper partition member is provided with a temperature compensating check valve for allowing oil to flow from the oil reservoir chamber to the upper oil chamber and for oil in the hydraulic oil chamber in the inner tube. vessel.   An annular oil chamber is defined between an inner periphery of the outer tube and an outer periphery of the inner tube, and the annular oil chamber communicates with an oil reservoir chamber through an oil hole provided in the inner tube. Hydraulic shock absorber as described in.

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