JP5456597B2 - Hydraulic shock absorber - Google Patents

Description

  The present invention relates to a hydraulic shock absorber.

  A suspension system such as an automobile has a suspension spring and a hydraulic shock absorber interposed between the vehicle body side (on the spring) and the axle side (under the spring), and absorbs the impact input based on the unevenness of the road surface by the expansion and contraction of the suspension spring. The expansion and contraction vibration of the suspension spring is controlled by the damping force of the hydraulic shock absorber to improve the running stability and riding comfort of automobiles.

  Conventionally, as a hydraulic shock absorber capable of adjusting a damping force characteristic according to vibration on the damper case side, there is one described in Patent Document 1.

  The hydraulic shock absorber described in Patent Document 1 is a hydraulic shock absorber that is mounted between a spring and an unsprung body of a vehicle, and is slidably fitted in a cylinder in which oil is sealed. A piston rod having one end connected to the piston and the other end extending to the outside of the cylinder, and a disk valve that generates a damping force by controlling the flow of oil generated by sliding of the piston A back pressure chamber that is provided on the back side of the disc valve and controls the opening of the disc valve by applying an internal pressure in the valve closing direction of the disc valve, and by moving the valve body in both directions from the neutral position. A damping force adjusting valve that adjusts an internal pressure of the back pressure chamber; and a weight that is movably provided by inertia with respect to the unsprung vibration and is connected to the valve body. The valve body and the weight of the damping force adjusting valve are held in a neutral position by a spring, and the damping force adjusting valve is switched by movement of the weight in both directions. As a result, the damping force adjustment valve adjusts the damping force on the expansion side and the contraction side to the hard side when the amplitude of the movement of the weight with respect to the expansion side and contraction side strokes of the piston rod is small. When the movement amplitude is large, the damping force on the expansion side is adjusted to the soft side, and the damping force on the contraction side is adjusted to the hard side. The force is adjusted to the soft side and the damping force on the extension side is adjusted to the hard side.

Japanese Patent No.4318071

  In the hydraulic shock absorber described in Patent Document 1, as means for adjusting the damping force of the damping valve according to the vibration on the damper case side, a weight that moves with respect to the vibration on the damper case side, The upper and lower springs to be held spontaneously and a damping force adjusting valve having a valve body to which the weight is connected are used, and a back pressure chamber is provided on the back side of the damping valve. By adjusting the internal pressure of the back pressure chamber of the damping valve with the damping force adjustment valve that is activated by the movement of the weight caused by the vibration on the damper case side, the valve opening pressure of the damping valve is adjusted, and the damping force is To be adjusted.

  Therefore, in the hydraulic shock absorber described in Patent Document 1, the means for adjusting the damping force of the damping valve according to the vibration on the damper case side includes not only the weight and the upper and lower springs but also the back pressure chamber and the damping force adjusting valve. It is necessary to provide it and it is complicated.

  In addition, the movement of the weight due to the vibration on the damper case side does not immediately adjust the valve opening pressure of the damping valve, but the damping valve opens via the change in the internal pressure of the back pressure chamber due to the operation of the damping force adjusting valve. It will adjust the valve pressure. Therefore, there is a delay in the response of adjusting the valve opening pressure of the damping valve in response to the vibration on the damper case side, and hence the damping force.

  An object of the present invention is to adjust a damping force characteristic quickly according to vibration on a damper case side with a simple configuration in a hydraulic shock absorber.

  According to the first aspect of the present invention, a piston rod attached to the other of the vehicle body side and the axle side is inserted into an oil chamber of a cylinder provided in a damper case attached to one of the vehicle body side and the axle side, and the tip of the piston rod is inserted. With the provided piston, the cylinder oil chamber is divided into a piston-side oil chamber and a rod-side oil chamber, and an oil reservoir chamber that compensates for the volume of the piston rod that moves forward and backward to the cylinder oil chamber communicates with the cylinder oil chamber. In the hydraulic shock absorber in which a damping force generation device is provided between the piston side oil chamber and the rod side oil chamber, the damping force generation device is fixed in two positions along the axial direction of the cylinder and is juxtaposed. And a second base piston, a pressure side damping valve is provided in the pressure side channel provided in the first base piston, an extension side damping valve is provided in the extension side channel provided in the second base piston, And the second A first spring for urging the compression side damping valve in the closing direction and an extension side damping valve are arranged back to back inside the weight housing chamber in which the piston is partitioned inside the cylinder. A weight that vibrates along the axial direction of the cylinder is held between the second spring that is biased in the closing direction.

  According to a second aspect of the present invention, a piston rod attached to the other of the vehicle body side and the axle side is inserted into an oil chamber of a cylinder provided in a damper case attached to one of the vehicle body side and the axle side, and the tip of the piston rod is inserted. With the provided piston, the cylinder oil chamber is divided into a piston-side oil chamber and a rod-side oil chamber, and an oil reservoir chamber that compensates for the volume of the piston rod that moves forward and backward to the cylinder oil chamber communicates with the cylinder oil chamber. A damping force generator is provided between the piston-side oil chamber and the rod-side oil chamber, and an outer flow path is provided around the cylinder oil chamber in the damper case to communicate the piston-side oil chamber and the rod-side oil chamber. The damping force generating device is provided with a pressure side flow path for flowing the oil in the piston side oil chamber of the cylinder from the outer flow path of the cylinder toward the rod side oil chamber in the pressure side stroke. Upstream The pressure side damping valve is provided on the downstream side, and the pressure side check valve is provided on the downstream side. The intermediate part between the pressure side damping valve and the pressure side check valve provided in the pressure side flow passage is connected to the oil reservoir chamber. The damping force generator is provided with an extension side flow channel for flowing the oil from the cylinder outer channel toward the piston side oil chamber. The extension side damping valve is provided upstream of the extension side channel, and the extension side is provided downstream. A hydraulic shock absorber provided with a check valve and having an intermediate portion between the extension side damping valve and the extension side check valve provided in the extension side flow path communicated with the oil reservoir chamber. The first and second base pistons are fixed and juxtaposed at two positions along the direction, and the compression side damping valve and the extension side check are respectively provided in the pressure side channel and the extension side channel provided in the first base piston. Each of the valves is provided with a second base fixie An extension side damping valve and a pressure side check valve are provided in each of the extension side flow path and the pressure side flow path provided in the cylinder, and the first and second base pistons are separated from each other inside the cylinder. Between the first spring for biasing the compression side damping valve in the closing direction and the second spring for biasing the extension side damping valve in the closing direction, the damping valve and the extension side damping valve are arranged back to back. A weight that vibrates along the axial direction is held.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the weight is composed of first and second weights, and the first and second weights move relative to each other along the axial direction of the cylinder. The first and second weights are provided with repulsive springs that mate with each other and divide the oil loading chamber therebetween and urge the two in a direction away from each other along the axial direction of the cylinder. The oil loading chamber divided by the two is provided with a flow path with a check valve and a flow path with a throttle communicating with the external weight storage chamber.

  The invention according to claim 4 is the invention according to claim 3, wherein the flow path with a check valve allows introduction of oil from the weight storage chamber to the oil loading chamber, and the first and second weights as a whole. It has a check valve that allows the length to be expanded.

  The invention according to claim 5 is the invention according to claim 3, wherein the flow path with a check valve allows the oil to be discharged from the oil loading chamber to the weight housing chamber, and the entire first and second weights are provided. A check valve that can reduce the length is provided.

(Claims 1 and 2)
(a) A pressure side damping valve and an extension side damping valve are arranged back-to-back inside the weight housing chamber in which the first and second base pistons are partitioned inside the cylinder, and the pressure side damping valve is biased in the closing direction. A weight that vibrates along the axial direction of the cylinder is held between the first spring and the second spring that urges the extension-side damping valve in the closing direction.

  Therefore, when the frequency of vibration on the damper case side becomes high and exceeds the natural frequency of the vibration system composed of the weight and the first and second springs, the weight and the damper case will vibrate in opposite phases.

  At this time, for example, when considering reversal from the compression side stroke to the extension side stroke, the damper case is on the upper end side of the vibration stroke, and the weight is on the lower end side of the vibration stroke. Since the second spring compressed by the weight strongly presses the expansion side damping valve in the closing direction (valve opening pressure: large), immediately after reversal from the compression side stroke to the expansion side stroke (the first half of the expansion side stroke) The extension side damping force is not normally swung from the neutral position by the suspension of the spring force of both springs (or both springs press the compression side damping valve and the extension side damping valve without a weight). Be bigger than in the state. When the extension stroke proceeds further (the second half of the extension stroke), the damper case moves to the lower end side of the vibration stroke, the weight moves to the upper end side of the vibration stroke, and the second spring compressed by the weight The spring force that presses the expansion-side damping valve in the closing direction becomes smaller (valve opening pressure: small), and the expansion-side damping force becomes gradually smaller than in the normal state described above.

  Therefore, according to the present invention, compared to the normal state, the damping force is increased in the first half of the extension side stroke, and the damping force is decreased in the second half. The same applies to the compression side stroke. Compared to the normal state, the damping force is increased in the first half of the compression side stroke and decreased in the second half. If this is schematically illustrated, it is as shown in FIG. 10. In FIG. 10, A indicates the damping force characteristic in the normal state, and B indicates the damping force characteristic corrected by the present invention.

  That is, in the hydraulic shock absorber, since the incompressible oil is actually compressed because it contains air or the like, there is a slight delay from when the pressure is applied until the pressure is increased. Also, at the time of reversal of expansion and contraction, for example, when switching from the compression side stroke to the expansion side stroke, it takes time until the pressure side check valve that has been opened until now is closed by the reversal of oil, and it is delayed until the oil chamber is increased in pressure. Produce. Accordingly, the damping force characteristic A in the normal state is delayed from the damping force characteristic B corrected by the present invention. According to the present invention, it is possible to correct the delay of the damping force characteristic of the damping valve in accordance with the vibration on the damper case side and improve the response.

  (b) The means for adjusting the damping force of the damping valve in accordance with the vibration on the damper case side is simple and includes only the first and second springs and the weight.

  (c) The vibration of the weight caused by the vibration on the damper case side immediately adjusts the valve opening pressure of the damping valve via the first and second springs. Therefore, the damping force characteristic of the damping valve can be quickly adjusted according to the vibration on the damper case side.

(Claims 3, 4, and 5)
(d) The weight is composed of a first weight and a second weight, the first weight and the second weight are fitted to each other so as to be relatively movable along the axial direction of the cylinder, and an oil loading chamber is defined between the two. In addition, the first and second weights are provided with repulsion springs that urge both of them in a direction away from each other along the axial direction of the cylinder, and the oil loading chamber partitioned by the both is communicated with the external weight housing chamber. A flow path with a check valve and a flow path with a throttle are provided.

  Here, when the flow path with the check valve includes a check valve that allows introduction of oil from the weight storage chamber to the oil loading chamber and that can expand the entire length of the first and second weights. In the state where the vibration frequency on the damper case side becomes higher and the acceleration acting on the first and second weights becomes larger, the weights are sandwiched between the repulsion spring and the first or second spring. The relative displacement occurs in the direction in which the distance between them increases. That is, the first and second weights are relatively displaced only in the direction of widening the interval between them by the acceleration acting on them without the stretching vibration due to the presence of the oil loaded in the oil loading chamber between them, At the same time, the oil introduced into the oil loading chamber from the weight storage chamber via the flow passage with the check valve is repeatedly held by the restriction of the flow passage with the restriction, and the interval is gradually increased. When the distance between the first and second weights is increased, the compression amount of the first and second springs is increased, and as a result, the valve opening pressure of the compression side damping valve and the extension side damping valve is increased. The value and the maximum value of the extension side damping force are increased. As a result, as the damper case (wheel) vibrates at a high frequency while the vehicle is traveling at high speed (the traveling speed is high), the distance between the first and second weights is increased, the damping force is increased, and stable traveling is obtained. It is done.

  On the other hand, if the flow path with the check valve is a check valve that allows oil to be discharged from the oil loading chamber to the weight storage chamber and can reduce the overall length of the first and second weights, As the frequency of vibration on the case side increases and the acceleration acting on the first and second weights increases, the weights are sandwiched between the repulsion spring and the first or second spring, and the distance between them is increased. Is relatively displaced in the direction of reduction. That is, the first and second weights are relatively displaced only in the direction in which the distance between them is reduced by the acceleration acting on them without the stretching vibration due to the presence of the oil loaded in the oil loading chamber between them, At the same time, the oil in the oil loading chamber is discharged to the weight storage chamber via the flow passage with check valve, and the oil in the oil loading chamber is repeatedly held by the restriction of the flow passage with the restriction, and the interval is gradually reduced. To do. When the distance between the first and second weights is reduced, the compression amount of the first and second springs is reduced, and as a result, the valve opening pressure of the compression side damping valve and the extension side damping valve is reduced. The value and the maximum value of the extension side damping force are lowered.

FIG. 1 is an overall cross-sectional view showing a hydraulic shock absorber. FIG. 2 is a cross-sectional view of the main part of FIG. FIG. 3 is a sectional view showing the damping force generator. FIG. 4 shows the flow of oil in the damping force generator, (A) shows the compression side stroke, and (B) is a cross-sectional view showing the extension side stroke. FIG. 5 shows a second base piston (extension side piston), (A) is a plan view, (B) is a sectional view, and (C) is a bottom view. FIG. 6 is an overall sectional view showing the hydraulic shock absorber. FIG. 7 is a cross-sectional view of the main part of FIG. FIG. 8 is a sectional view showing the damping force generator. FIG. 9 shows the oil flow in the damping force generator, (A) shows the compression side stroke, and (B) is a cross-sectional view showing the extension side stroke. FIG. 10 is a diagram showing damping force characteristics.

  In the hydraulic shock absorber 10, as shown in FIGS. 1 to 3, a damper case 11 attached to the axle side has a damper tube 12, and a damper cylinder 13 is inserted into the damper tube 12. The hydraulic shock absorber 10 slidably inserts a piston rod 14 attached to the vehicle body side into the damper tube 12 and the center of the cylinder 13 of the damper case 11, and is suspended on the damper case 11 and the outer portion of the piston rod 14. A spring 15 is interposed.

  The damper case 11 includes an axle side mounting member 16 at the center of the outer surface of the bottom cap 12 </ b> A of the damper tube 12, and the piston rod 14 includes a vehicle body side mounting member 17. A spring receiver 18 is provided on the outer peripheral portion of the damper tube 12 in the damper case 11, and a spring receiver 19 is provided on the outer peripheral portion of the vehicle body side mounting member 17 in the piston rod 14. The suspension spring 15 is interposed between the spring receiver 18 and the spring receiver 19 and absorbs the impact force that the vehicle receives from the road surface due to the spring force of the suspension spring 15.

  The damper tube 12 of the damper case 11 includes a rod guide 21 through which the piston rod 14 penetrates at an opening thereof. The rod guide 21 has a large outer diameter portion of the head 21A inserted in a fluid-tight manner in the damper tube 12, and a piston rod 14 is slidably inserted in an inner diameter portion including an oil seal 22 and a bush 23 in a fluid-tight manner. ing.

  In the hydraulic shock absorber 10, a damper case 11 has a cylinder 13 inserted in a damper tube 12, and the cylinder 13 is composed of an outer cylinder 13A and an inner cylinder 13B. The damper case 11 is disposed on the outer periphery of the cup-shaped bottom cap 12A. The inner periphery of the lower end of the damper tube 12 is fitted and fixed by welding or the like.

  The outer periphery of the body 24A of the cup-shaped bottom plate 24 made of a steel plate press is fitted into the inner periphery of the cup of the bottom cap 12A so as to be centered. The inner periphery of the fitting cylinder portion 24D rising from the outer periphery of the flange 24C of the bottom plate 24 mounted on the upper end surface of the cup of the bottom cap 12A is provided on the outer periphery of the second base piston 60 described later. A large outer diameter portion is press-fitted and is centered. The lower end surface of the second base piston 60 is placed on the upper surface of the flange 24 </ b> C of the bottom plate 24. Then, the inner circumferences of the lower ends of the outer cylinder 13A and the inner cylinder 13B of the cylinder 13 are fixed by being press-fitted into the middle and outer diameter parts and the outer diameter part of the outer circumference of the second base piston 60, respectively.

  On the other hand, the inner periphery of each upper end of the outer cylinder 13A and the inner cylinder 13B of the cylinder 13 is fixed by press-fitting or the like into the middle outer diameter portion and the small outer diameter portion provided below the head portion 21A of the rod guide 21, respectively. The damper tube 12 is inserted with the head portion 21A of the rod guide 21 and protrudes upward from the oil seal 22 on the head portion 21A and the washer 22A provided on the upper surface of the oil seal 22, and crimps the protruding end. Part 12B. The damper tube 12 is provided between the bottom cap 12A and the caulking portion 12B via the rod guide 21, the oil seal 22, the washer 22A, the bottom plate 24, and the second base piston 60. The cylinder 13B is sandwiched and fixed in the axial direction.

  As described above, in the hydraulic shock absorber 10, the entire damper case 11 is a triple tube in which the damper tube 12 and the outer cylinder 13 </ b> A and the inner cylinder 13 </ b> B of the cylinder 13 are coaxially arranged. An oil chamber 27 composed of a piston side oil chamber 27A and a rod side oil chamber 27B is formed inside the inner cylinder 13B, and the piston side oil chamber 27A and the rod side oil are formed by an annular gap between the outer cylinder 13A and the inner cylinder 13B. An outer flow path 13C that communicates with the chamber 27B is formed, and an annular gap between the damper tube 12 and the outer cylinder 13A is defined as an air chamber 31 and an oil reservoir chamber 32.

  That is, when the piston 10 is inserted into the damper tube 12 of the damper case 11 and the center of the cylinder 13, the hydraulic shock absorber 10 fixes the piston 25 inserted at the tip of the piston rod 14 with the nut 26. The oil chamber 27 of the cylinder 13 is partitioned into a piston-side oil chamber 27A and a rod-side oil chamber 27B by a piston 25 slidably inserted into the inner periphery of the cylinder 13B. 28 is a rebound spring and 29 is a bump rubber.

  The hydraulic shock absorber 10 is provided with an air chamber 31 and an oil reservoir chamber 32 above and below the annular gap between the damper tube 12 and the outer cylinder 13 </ b> A so that the oil reservoir chamber 32 communicates with the oil chamber 27 of the cylinder 13. The oil reservoir chamber 32 compensates the volume of the piston rod 14 (including the volume of oil temperature expansion) that advances and retreats to the oil chamber 27 of the cylinder 13.

  The hydraulic shock absorber 10 is provided with a damping force generator 40 between the piston side oil chamber 27A and the rod side oil chamber 27B of the cylinder 13.

  The damping force generator 40 includes first and second base pistons 50 and 60 that are fixed and juxtaposed at two positions along the axial direction of the cylinder 13.

  The damping force generator 40 is a valve unit 40A in which the first and second base pistons 50, 60 are fixedly provided around the bolt 70, and the inner circumferences of the lower ends of the outer cylinder 13A and the inner cylinder 13B of the cylinder 13 respectively. It is inserted into and built in.

  The valve unit 40A of the damping force generating device 40 includes a pressure side check valve 52 (valve spring 52A), a second side, and a second check valve 52 that is loaded in a skewered manner on the outer periphery of the rod-like screw portion 71B in order from the head 71A side of the bolt 70. Base piston 60, extension side damping valve 61, valve stopper 72A, collar 80A of damping force adjusting device 80 described in detail later, valve stopper 72B, compression side damping valve 51, first base piston 50, extension side check valve 62, valve A stopper 73 is provided, and these are fixed by a nut 71 </ b> C that is screwed to the rod-like screw portion 71 </ b> B.

  As described above, the valve unit 40A of the damping force generator 40 has the large outer diameter portion of the outer periphery of the second base piston 60 with respect to the flange 24C and the fitting cylinder portion 24D of the bottom plate 24 fitted into the bottom cap 12A. As shown above, the outer periphery of the outer cylinder 13A of the cylinder 13 and the inner periphery of the inner cylinder 13B are assembled to the inner and outer diameter parts of the outer periphery of the second base piston 60 as described above. The first base piston 50 is liquid-tightly inserted into the inner periphery of the inner cylinder 13B of the cylinder 13 through an O-ring provided on the outer periphery. As a result, the second base piston 60 of the valve unit 40A is fixed to the bottom on the one end side of the cylinder 13, and the first base piston 50 of the valve unit 40A is fixed to the inner periphery of the cylinder 13.

  The damping force generator 40 uses an annular space sandwiched between the first base piston 50 and the second base piston 60 inside the inner cylinder 13 </ b> B as a pressure expansion shared flow channel 41. An upper space of the first base piston 50 in the inner cylinder 13B is defined as a piston-side oil chamber 27A. The space below the second base piston 60 in the inner cylinder 13B is a hole-shaped flow path 60C formed in the second base piston 60, and the outer flow between the outer cylinder 13A and the inner cylinder 13B of the cylinder 13. A common pressure expansion flow path 42 communicates with the rod-side oil chamber 27B via the path 13C. In the upper end side of the inner cylinder 13B, in the present embodiment, a small outer diameter portion of the rod guide 21 is formed with a notch common pressure increasing flow path 43 that communicates the rod side oil chamber 27B with the outer flow path 13C.

  The damping force generating device 40 includes a first base piston 50 provided with a pressure side channel 50A that is opened and closed by a compression side damping valve 51 and an extension side channel 50B that is opened and closed by an extension side check valve 62, and a second base piston. 60 is provided with a pressure side channel 60B opened and closed by a pressure side check valve 52 and an extension side channel 60A opened and closed by an extension side damping valve 61. The damping force generator 40 includes the pressure expansion shared channels 41, 42, 43, the pressure side channel 50 </ b> A provided in the first base piston 50, the extension side channel 50 </ b> B, and the pressure side provided in the second base piston 60. The piston-side oil chamber 27A of the cylinder 13 is connected to the piston-side oil chamber 27A via the passage 60B, the extension-side passage 60A, the hole-like passage 60C, and the outer passage 13C provided in the annular gap between the outer cylinder 13A and the inner cylinder 13B. The rod-side oil chamber 27B is communicated (the piston 25 is not provided with a flow path that communicates the piston-side oil chamber 27A and the rod-side oil chamber 27B).

  The damping force generation device 40 includes an intermediate portion between the compression side damping valve 51 and the compression side check valve 52 provided in each of the pressure side flow paths 50A and 60B of the first base piston 50 and the second base piston 60 (the pressure expansion shared flow path 41). And the extension side check valve and the extension side check valve provided in the extension side flow paths 50B and 60A of the first base piston 50 and the second base piston 60, respectively. The second base piston 60 is provided with a communication path 44 that communicates the intermediate portion 62 (portion communicating with the pressure-sharing shared flow channel 41) with the oil reservoir 32.

  The second base piston 60 is a part of the outer periphery of the large outer diameter portion that is press-fitted into the fitting cylinder portion 24D of the bottom plate 24 when assembled in the damper tube 12 and the cylinder 13 of the damper case 11 as described above. On the oil reservoir 32. Then, as shown in FIG. 5, the second base piston 60 is provided with a lateral hole that reaches a middle portion of the pressure side flow path 60 </ b> B in the radial direction from a part of the outer periphery of the large outer diameter portion. The horizontal hole is a communication path 44.

  Therefore, in the damping force generator 40 of the hydraulic shock absorber 10, the oil in the piston-side oil chamber 27A of the cylinder 13 flows from the outer flow path 13C of the cylinder 13 toward the rod-side oil chamber 27B in the compression-side stroke. The pressure side flow path (pressure expansion shared flow paths 41, 42, 43, pressure side flow paths 50A, 60B, hole flow path 60C) is used, and this pressure side flow path (pressure expansion shared flow paths 41, 42, 43, pressure side flow paths). 50A, 60B, hole-like flow path 60C) is provided with a pressure-side damping valve 51 on the upstream side and a pressure-side check valve 52 on the downstream side. This pressure-side flow path (pressure expansion shared flow paths 41, 42, 43, pressure-side flow path 50A). , 60B, and the hole-like flow path 60C), an intermediate portion between the pressure-side damping valve 51 and the pressure-side check valve 52 is communicated with the oil reservoir chamber 32 via the communication path 44.

  Further, in the extension side stroke, the extension side passage (flow expansion common passages 41, 42,...) Flows the oil in the rod side oil chamber 27B of the cylinder 13 from the outer passage 13C of the cylinder 13 toward the piston side oil chamber 27A. 43, the extension side channels 50B and 60A, the hole-like channel 60C), and this extension side channel (the pressure-extended channels 41, 42, 43, the extension side channels 50B and 60A, the hole-like channel 60C). An extension side damping valve 61 is provided on the upstream side, and an extension side check valve 62 is provided on the downstream side. This extension side flow path (pressure extension shared flow paths 41, 42, 43, extension side flow paths 50B, 60A, hole-like flow) The intermediate portion of the expansion side damping valve 61 and the expansion side check valve 62 in the path 60C) is communicated with the oil reservoir chamber 32 via the communication path 44.

Therefore, the hydraulic shock absorber 10 performs a damping action as follows.
(Pressure side stroke) (flow of solid line arrow in FIG. 4A)
The oil in the piston-side oil chamber 27A is pressurized, and the pressure-side damping valve 51 of the pressure-side flow path 50A of the first base piston 50 of the damping force generator 40 is pushed open to generate a pressure-side damping force. The oil flowing out from the pressure side damping valve 51 to the pressure expansion common channel 41 is divided into two in the pressure side channel 60B of the second base piston 60, and one oil is the pressure side of the pressure side channel 60B of the second base piston 60. Outflow from the check valve 52 to the rod side oil chamber 27B through the pressure expansion common flow path 42, the hole-shaped flow path 60C of the second base piston 60, the outer flow path 13C of the cylinder 13 and the pressure expansion common flow path 43, The other oil is discharged from the communication path 44 of the second base piston 60 to the oil reservoir 32. The other oil discharged to the oil reservoir chamber 32 compensates the oil corresponding to the entry volume of the piston rod 14.

(Extension side stroke) (flow of solid line arrow in FIG. 4B)
The oil in the rod-side oil chamber 27B is pressurized, passes through the pressure-extended flow path 43, the outer flow path 13C of the cylinder 13, and the hole-shaped flow path 60C of the second base piston 60 of the damping force generating device 40. It flows into the flow path 42 and pushes and opens the expansion side damping valve 61 of the expansion side flow path 60A of the second base piston 60 to generate the expansion side damping force. After the oil flowing out from the expansion side damping valve 61 to the pressure expansion common flow path 41 joins with the oil replenished from the oil reservoir chamber 32 through the communication path 44 of the second base piston 60 and the pressure side flow path 60B. Then, the gas flows out into the piston side oil chamber 27A through the extension side check valve 62 of the extension side flow path 50B of the first base piston 50. The oil replenished from the oil reservoir 32 compensates for the retraction volume of the piston rod 14.

Therefore, according to the present embodiment, the following operational effects can be obtained.
(a) In the damping force generating device 40 of the hydraulic shock absorber 10, the damping force generating device 40 is provided between the piston side oil chamber 27A and the rod side oil chamber 27B of the cylinder 13, and the piston side of the cylinder 13 is moved in the pressure side stroke. Pressure side flow channel (pressure expansion common flow channels 41, 42, 43, pressure side flow channels 50A, 60B, hole flow channel 60C) for flowing the oil in oil chamber 27A from outer flow channel 13C of cylinder 13 toward rod side oil chamber 27B ), The pressure-side damping valve 51 is located upstream of the pressure-side flow channel (pressure-reducing common flow channels 41, 42, 43, pressure-side flow channels 50A, 60B, and hole-shaped flow channel 60C), and the pressure-side check valve 52 is located downstream. And connecting the intermediate portion between the pressure side damping valve 51 and the pressure side check valve 52 in the pressure side flow path (pressure expansion common flow paths 41, 42, 43, pressure side flow paths 50A, 60B, hole flow path 60C) through the communication path 44. Via the oil reservoir 32 In the extension side stroke, the extension side passage (the pressure extension common passages 41, 42, 43) flows the oil in the rod side oil chamber 27B of the cylinder 13 from the outer passage 13C of the cylinder 13 toward the piston side oil chamber 27A. , The extension side channels 50B and 60A, the hole-like channel 60C), and the extension side channels (the pressure-extended channels 41, 42 and 43, the extension side channels 50B and 60A, the hole-like channel 60C). An extension side damping valve 61 is provided on the upstream side, and an extension side check valve 62 is provided on the downstream side. 60C), an intermediate portion between the expansion side damping valve 61 and the expansion side check valve 62 was communicated with the oil reservoir chamber 32 via the communication path 44.

  In the pressure side stroke, the pressure-rised oil in the piston side oil chamber 27A is upstream of the pressure side flow path (pressure expansion common flow paths 41, 42, 43, pressure side flow paths 50A, 60B, hole flow path 60C) of the damping force generator 40. A compression side damping force is generated through the compression side damping valve 51 on the side. One of the oils flowing out from the pressure side damping valve 51 flows from the pressure side check valve 52 through the outer flow path 13C of the cylinder 13 into the rod side oil chamber 27B. Further, the flow of the oil corresponding to the volume of the piston rod 14 that is the other of the oil flowing out from the compression side damping valve 51 flows from the communication path 44 of the second base piston 60 to the oil reservoir 32. Inflow. At this time, the pressure in the rod side oil chamber 27B substantially depends only on the pressure in the air chamber 31 (because the flow path resistance of the pressure side check valve 52 downstream of the pressure side damping valve 51 to the outer flow path 13C of the cylinder 13 is small). It does not vary depending on the setting of the flow resistance of the compression side damping valve 51. Therefore, it is possible to avoid the reduction of the damping force when the extension side is reversed.

  In the extension stroke, the pressure-rised oil in the rod-side oil chamber 27B is expanded from the outer passage 13C of the cylinder 13 to the extension passage (the pressure increase common passages 41, 42, 43, the extension passage 50B) of the damping force generator 40. , 60A, and the hole-like channel 60C), the extension side damping force is generated through the extension side damping valve 61 on the upstream side. The oil flowing out from the extension side damping valve 61 joins the oil corresponding to the retraction volume of the piston rod 14 replenished from the oil reservoir chamber 32 through the communication path 44 of the second base piston 60, and then the extension side check is performed. It flows into the piston-side oil chamber 27A through the valve 62.

  In addition, by setting the pressure of the air chamber 31 that pressurizes the oil reservoir chamber 32 to a high pressure, the pressure response of the rod side oil chamber 27B can be increased to a positive pressure in the pressure side stroke, and the damping response at the time of reversing the extension side can be improved.

  (b) An intermediate portion between the pressure side damping valve 51 and the pressure side check valve 52 provided in each of the pressure side flow paths 50A and 60B of the first and second base pistons 50 and 60 is communicated with the oil reservoir chamber 32, and A communication path 44 that communicates an intermediate portion of the extension side damping valve 61 and the extension side check valve 62 provided in each of the extension side flow paths 50B and 60A of the first and second base pistons 50 and 60 with the oil reservoir chamber 32. The second base piston 60 is provided. Thereby, in the compression side stroke, the oil flow path of the above-mentioned (a) flowing out from the piston side oil chamber 27A through the damping force generating device 40 to the oil reservoir chamber 32, and the oil stroke chamber 32 is attenuated in the extension side stroke. The above-described oil flow path (a) flowing out to the piston-side oil chamber 27 </ b> A through the force generator 40 is formed by the communication path 44 provided in the second base piston 60. The communication path 44 is a flow path such as a simple lateral hole, and easily secures the flow path area of the oil chamber 27 to the oil reservoir chamber 32 of the cylinder 13, and the pressure of the air chamber 31 is smoothly adjusted to the rod side oil chamber 27 </ b> B. Therefore, it is possible to more reliably avoid the damping force when reversing the extension side. In addition, the communication path 44 can be set to have a short flow path length and a small flow path resistance, and the setting flexibility can be improved. Further, the communication path 44 can be formed only by drilling the second base piston 60, and the cost can be reduced without increasing the number of parts.

  (c) In the hydraulic shock absorber 10, an outer flow path 13 </ b> C that communicates the piston-side oil chamber 27 </ b> A and the rod-side oil chamber 27 </ b> B is provided around the oil chamber 27 of the cylinder 13 in the damper case 11. An oil reservoir 32 is provided around the oil chamber 27 and the outer flow path 13C. Therefore, the oil chamber 27 is provided at the center of the cylinder 13 in the damper case 11, the outer flow path 13C is provided outside the oil chamber 27, and the oil reservoir chamber 32 is provided further outside the outer flow path 13C. Accordingly, in the hydraulic shock absorber 10, the oil chamber 27, the outer flow path 13C, and the oil reservoir chamber 32 of the cylinder 13 can be provided in the inside of the damper case 11 having a short overall length without increasing the length of the damper case 11. Thus, the degree of freedom in layout in a vehicle on which this is mounted can be improved.

  (d) The damper case 11 inserts and fits the cylinder 13 into the damper tube 12, the cylinder 13 includes an outer cylinder 13A and an inner cylinder 13B, the oil chamber 27 is formed in the inner cylinder 13B, and the outer cylinder 13A The outer flow path 13C is formed between the inner cylinder 13B and the oil reservoir chamber 32 between the damper tube 12 and the outer cylinder 13A. Due to the triple tube structure comprising the damper tube 12 and the outer cylinder 13A and the inner cylinder 13B of the cylinder 13, the above (c) can be realized in a compact manner.

  (e) The first and second base pistons 50 and 60 are fixedly provided around the bolt 70, and the second base piston 60 is fixed to the bottom of one end side of the cylinder 13. Therefore, the first and second base pistons 50 and 60 can be easily assembled at two positions along the axial direction of the cylinder 13.

  Note that the damping force generator 40 compresses the pressure side check valve 52 provided on the downstream side of the pressure side flow path (pressure expansion common flow paths 41, 42, 43, pressure side flow paths 50A, 60B, and hole-shaped flow path 60C). A force generating means may be attached. This pressure side damping force generating means can be configured by using the pressure side check valve 52 as a laminated plate valve and / or the pressure side flow path 60B provided with the pressure side check valve 52 as a throttle flow path.

  According to this, in the pressure side stroke, one of the oils flowing out from the upstream pressure side damping valve 51 flows from the pressure side check valve 52 through the outer flow path 13C of the cylinder 13 to the rod side oil chamber 27B. However, the pressure side check valve 52 performs the pressure side damping force generation function together with the check function. The pressure side check valve 52 generates a damping force ΔF depending on the piston speed, and the pressure Pr of the rod side oil chamber 27B is a value obtained by subtracting ΔF from the pressure Pa of the air chamber 31 that pressurizes the oil reservoir chamber 32, in other words, the piston. The value is controlled depending on the speed.

  Controlling the pressure Pr of the rod-side oil chamber 27B in this way on the pressure side stroke depending on the piston speed means that the rising characteristic of the damping force at the time of reversing the extension side can be controlled depending on the piston speed. When the piston speed is high, ΔF increases due to the restriction of the compression side check valve 52, and Pr decreases. Therefore, the rising of the damping force at the time of reversing the extension side becomes gentle and the riding comfort is improved. When the piston speed is low, ΔF due to the restriction of the pressure side check valve 52 becomes small and Pr becomes large. Therefore, the rise of the damping force at the time of reversing the extension side becomes abrupt and suppresses the fluffy feeling of the vehicle body and improves the running stability. To do.

  At this time, the total amount of the compression side damping force is the sum of the damping force of the compression side damping valve 51 and the damping force of the compression side check valve 52, but in a normal setting, the damping force of the compression side damping valve 51 is made larger. The total amount of the compression side damping force largely depends on the damping force of the compression side damping valve 51.

  Further, the damping force generating device 40 includes an extension side check valve 62 provided on the downstream side of the extension side flow path (the pressure extension common flow paths 41, 42, 43, the extension side flow paths 50B, 60A, and the hole-like flow path 60C). The extension side damping force generation means may be attached to the sword. This extension side damping force generating means can be configured by using, for example, the extension side check valve 62 as a laminated plate valve and / or the extension side channel 50B provided with the extension side check valve 62 as a throttle channel.

  According to this, in the extension side stroke, one of the oils flowing out from the upstream side extension damping valve 61 flows from the extension side check valve 62 through the outer flow path 13C of the cylinder 13 to the piston side. Although flowing into the oil chamber 27A, the extension side check valve 62 performs the extension side damping force generation function together with the check function. The extension side check valve 62 generates a damping force ΔF depending on the piston speed, and the pressure Pp of the piston side oil chamber 27A is a value obtained by subtracting ΔF from the pressure Pa of the air chamber 31 that pressurizes the oil reservoir chamber 32, in other words. The value is controlled depending on the piston speed.

  The fact that the pressure Pp of the piston-side oil chamber 27A is controlled depending on the piston speed in the extension stroke in this way means that the rising characteristic of the damping force at the time of pressure-side reversal can be controlled depending on the piston speed. When the piston speed is high, ΔF increases due to the restriction of the extension side check valve 62, and Pp decreases. Therefore, the rise of the damping force at the time of pressure side reversal becomes gentle and the riding comfort is improved. When the piston speed is low, ΔF due to the restriction of the extension side check valve 62 becomes small and Pp becomes large. Therefore, the rise of the damping force at the time of reversing the pressure side becomes abrupt and suppresses the fluffy feeling of the vehicle body and improves running stability. To do.

  At this time, the total amount of the extension side damping force is the sum of the damping force of the extension side damping valve 61 and the damping force of the extension side check valve 62. However, in a normal setting, the damping force of the extension side damping valve 61 is more increased. Enlarge. The total amount of the extension side damping force largely depends on the damping force of the extension side damping valve 61.

  However, the hydraulic shock absorber 10 includes the above-described damping force adjusting device 80 as follows in order to quickly adjust the damping force characteristic according to the vibration on the damper case side with a simple configuration.

  As shown in FIG. 3, the damping force adjusting device 80 includes a first spring 81 (spring constant K1) around the collar 80A incorporated in the bolt 70 of the valve unit 40A of the damping force generating device 40 as described above. A second spring 82 (spring constant K2) and a weight 83 (mass M) are provided.

  That is, the damping force adjusting device 80 is provided inside the weight housing chamber 80B (same as the pressure-extension common flow channel 41) in which the first and second base pistons 50 and 60 are partitioned inside the inner cylinder 13B of the cylinder 13. The compression side damping valve 51 and the extension side damping valve 61 are arranged back to back, and a first spring 81 that biases the compression side damping valve 51 in the closing direction and a second spring that biases the extension side damping valve 61 in the closing direction. A weight 83 that vibrates along the axial direction of the cylinder 13 is held between the weight 82 and the cylinder 82. The first spring 81 is interposed between the back surface of the compression side damping valve 51 and the weight 83, and the second spring 82 is interposed between the back surface of the extension side damping valve 61 and the weight 83.

  The weight 83 is provided with bushes 83A and 83A on the inner circumferences at both ends, and vibrates along the axial direction of the cylinder 13 in a state of slidingly contacting the outer circumference of the collar 80A via the bushes 83A. On the outer periphery of both ends of the collar 80A, annular rubber stoppers 84, 84 mounted on the valve stoppers 72A, 72B are inserted and fixed, and the weight 83 reaching the vibration stroke end is brought into contact with the stoppers 84 To buffer and regulate its vibration stroke.

Therefore, according to the present embodiment, the following operational effects can be obtained.
(f) Inside the weight housing chamber 80B in which the first and second base pistons 50 and 60 are partitioned inside the cylinder 13, the compression side damping valve 51 and the extension side damping valve 61 are arranged back to back, and the compression side damping valve 51 A weight 83 that vibrates along the axial direction of the cylinder 13 is held between a first spring 81 that urges the cylinder 13 in the closing direction and a second spring 82 that urges the expansion-side damping valve 61 in the closing direction. did.

  Therefore, when the frequency of vibration on the damper case 11 side becomes high and this exceeds the natural frequency of the vibration system composed of the weight 83 and the first and second springs 81 and 82, the weight 83 and the damper case 11 are in antiphase. To vibrate.

  At this time, for example, when considering reversal from the compression side stroke to the extension side stroke, the damper case 11 is on the upper end side of the vibration stroke, and the weight 83 is on the lower end side of the vibration stroke. Since the second spring 82 compressed by the weight 83 strongly presses the expansion side damping valve 61 in the closing direction (valve opening pressure: large), immediately after reversal from the compression side stroke to the expansion side stroke (of the expansion side stroke) The first-side extension side damping force is such that the weight 83 is not shaken from the neutral position by the suspension of the spring force of the two springs 81, 82 (or the pressure-side damping valve 51 in a state where the two springs 81, 82 are not accompanied by the weight 83. And the expansion side damping valve 61 is pressed), which is larger than in the normal state. When the extension side stroke further proceeds (the second half of the extension side stroke), the damper case 11 moves to the lower end side of the vibration stroke, the weight 83 moves to the upper end side of the vibration stroke, and is compressed by the weight 83. The spring force by which the spring 82 presses the expansion side damping valve 61 in the closing direction becomes smaller (valve opening pressure: small), and the expansion side damping force becomes gradually smaller than in the above-described normal state.

  Therefore, according to the present invention, compared to the normal state, the damping force is increased in the first half of the extension side stroke, and the damping force is decreased in the second half. The same applies to the compression side stroke. Compared to the normal state, the damping force is increased in the first half of the compression side stroke and decreased in the second half. If this is schematically illustrated, it is as shown in FIG. 10. In FIG. 10, A indicates the damping force characteristic in the normal state, and B indicates the damping force characteristic corrected by the present invention.

  That is, in the hydraulic shock absorber 10, since the incompressible oil is actually compressed because it contains air, a slight delay occurs between the time when pressure is applied and the time when pressure is increased. In addition, when reversing the expansion and contraction, for example, when switching from the compression side stroke to the expansion side stroke, it takes time until the compression side check valve 52 that has been opened is closed by reversing the oil until the oil chamber 27 is increased in pressure. Cause a delay. Accordingly, the damping force characteristic A in the normal state is delayed from the damping force characteristic B corrected by the present invention. According to the present invention, the delay of the damping force characteristics of the damping valves 51 and 61 can be corrected in accordance with the vibration on the damper case 11 side, and the response can be improved.

  (g) The means for adjusting the damping force of the damping valves 51 and 61 according to the vibration on the damper case 11 side is configured only by using the first and second springs 81 and 82 and the weight 83, and is simple. is there.

  (h) The vibration of the weight 83 caused by the vibration on the damper case 11 side immediately adjusts the valve opening pressure of the damping valves 51 and 61 via the first and second springs 81 and 82. Therefore, the damping force characteristics of the damping valves 51 and 61 can be quickly adjusted according to the vibration on the damper case 11 side.

  The hydraulic shock absorber 100 shown in FIGS. 6 to 9 is a modification of the hydraulic shock absorber 10 shown in FIGS. The hydraulic shock absorber 100 is different from the hydraulic shock absorber 10 in that the damping force adjusting device 80 is replaced with a damping force adjusting device 110.

  As shown in FIG. 8, the damping force adjusting device 110 includes a first spring 111 (spring constant K1) and a second spring around the collar 110A incorporated in the bolt 70 of the valve unit 40A of the damping force generating device 40. 112 (spring constant K2) and weight 120 (mass M1, M2) are provided.

  That is, the damping force adjusting device 110 is provided inside the weight housing chamber 110B (same as the pressure-extension common flow channel 41) in which the first and second base pistons 50 and 60 are partitioned inside the inner cylinder 13B of the cylinder 13. The compression side damping valve 51 and the extension side damping valve 61 are arranged back to back, and a first spring 111 that biases the compression side damping valve 51 in the closing direction and a second spring that biases the extension side damping valve 61 in the closing direction. A weight 120 that vibrates along the axial direction of the cylinder 13 is held between the cylinder 112 and the cylinder 112. The first spring 111 is interposed between the back surface of the compression side damping valve 51 and the weight 120, and the second spring 112 is interposed between the back surface of the extension side damping valve 61 and the weight 120.

  The weight 120 includes a first weight 121 (mass M1) and a second weight 122 (mass M2). The first weight 121 and the second weight 122 have different natural frequencies. The first weight 121 and the second weight 122 can be moved relative to each other along the axial direction of the cylinder 13 by fitting the inner periphery of the second weight 122 to the outer periphery of the first weight 121, for example. The oil loading chamber 123 is defined between the two. The first weight 121 is provided by press-fitting a bush 121A on the inner periphery of the end opposite to the second weight 122, and the second weight 122 is provided on the inner periphery of the end opposite to the first weight 121. A bush 122A is provided by press-fitting or the like. The first weight 121 and the second weight 122 vibrate along the axial direction of the cylinder 13 while being in sliding contact with the outer periphery of the collar 110A via the bushes 121A and 122A. Annular rubber stoppers 113 and 113 are inserted and fixed on the outer periphery of both ends of the collar 110A, and the weights 121 and 122 reaching the vibration stroke end are brought into contact with the stoppers 113 to buffer the vibration stroke. To regulate.

  The first weight 121 and the second weight 122 include a repulsion spring 124 that biases them in a direction away from each other along the axial direction of the cylinder 13. The repulsion spring 124 is provided around the collar 110 </ b> A inside the oil loading chamber 123.

  The first weight 121 and the second weight 122 include a flow path 125 with a check valve and a flow path 126 with a throttle that communicates an oil loading chamber 123 that is partitioned between the first weight 121 and the second weight 122 to the external weight storage chamber 110B.

  The flow path 125 with a check valve allows oil to be introduced from the weight accommodating chamber 110B into the oil loading chamber 123, and the entire length of the first weight 121 and the second weight 122 (the first direction in the axial direction of the cylinder 13). Check valve 125A (valve spring 125B) that allows the distance L (FIG. 8) between the surface of the first weight 121 supporting the first spring 111 and the surface of the second weight 122 to support the second spring 112 to be enlarged. Have As shown in FIG. 8C, the second weight 122 is formed by fitting and integrating the divided bodies 122U and 122L divided into two in the axial direction, and the check valves 125A and 122L between the divided bodies 122U and 122L. A valve spring 125B is incorporated.

  For example, the narrowed flow passage 126 is an annular gap 126A (an annular gap that communicates the oil loading chamber 123 with the external weight housing chamber 110B) at the fitting portion between the outer periphery of the first weight 121 and the inner periphery of the second weight 122. The oil flow resistance from the oil loading chamber 123 to the weight storage chamber 110B is increased. The flow path with throttle 126 is an oil of an orifice 126A (an orifice communicating the oil loading chamber 123 with the external weight storage chamber 110B) provided in the check valve 125A or a first weight 121 (or the second weight 122 is acceptable). It can also be configured by an orifice 126A drilled in the wall facing the loading chamber 123 and the weight storage chamber 110B.

Therefore, according to the present embodiment, in addition to (a) to (e) in the hydraulic shock absorber 10 described above, the following operational effects are obtained.
(f) Inside the weight housing chamber 110B in which the first and second base pistons 50 and 60 are partitioned inside the cylinder 13, the compression side damping valve 51 and the extension side damping valve 61 are arranged back to back, and the compression side damping valve 51 A weight 120 that vibrates along the axial direction of the cylinder 13 is held between the first spring 111 that urges the cylinder 13 in the closing direction and the second spring 112 that urges the expansion-side damping valve 61 in the closing direction. did.

  Therefore, when the frequency of vibration on the damper case 11 side increases and this exceeds the natural frequency of the vibration system composed of the weight 120 and the first and second springs 111 and 112, the weight 120 and the damper case 11 are in antiphase. To vibrate.

  At this time, for example, when considering reversal from the compression side stroke to the extension side stroke, the damper case 11 is on the upper end side of the vibration stroke, and the weight 120 is on the lower end side of the vibration stroke. Since the second spring 112 compressed by the weight 120 strongly presses the expansion-side damping valve 61 in the closing direction (valve opening pressure: large), immediately after reversal from the compression-side stroke to the expansion-side stroke (of the expansion-side stroke) In the first half, the extension side damping force is such that the weight 120 is not shaken from the neutral position by the suspension of the spring force of the two springs 111, 112 (or the compression side damping valve 51 in a state where the two springs 111, 112 are not accompanied by the weight 120. And the expansion side damping valve 61 is pressed), which is larger than in the normal state. When the extension side stroke further proceeds (the second half of the extension side stroke), the damper case 11 moves to the lower end side of the vibration stroke, and the weight 120 moves to the upper end side of the vibration stroke, and is compressed by the weight 120. The spring force with which the spring 112 presses the expansion side damping valve 61 in the closing direction becomes smaller (valve opening pressure: small), and the expansion side damping force becomes gradually smaller than in the above-described normal state.

  Therefore, according to the present invention, compared to the normal state, the damping force is increased in the first half of the extension side stroke, and the damping force is decreased in the second half. The same applies to the compression side stroke. Compared to the normal state, the damping force is increased in the first half of the compression side stroke and decreased in the second half. If this is schematically illustrated, it is as shown in FIG. 10. In FIG. 10, A indicates the damping force characteristic in the normal state, and B indicates the damping force characteristic corrected by the present invention.

  That is, in the hydraulic shock absorber 10, since the incompressible oil is actually compressed because it contains air, a slight delay occurs between the time when pressure is applied and the time when pressure is increased. In addition, when reversing the expansion and contraction, for example, when switching from the compression side stroke to the expansion side stroke, it takes time until the compression side check valve 52 that has been opened is closed by reversing the oil until the oil chamber 27 is increased in pressure. Cause a delay. Accordingly, the damping force characteristic A in the normal state is delayed from the damping force characteristic B corrected by the present invention. According to the present invention, the delay of the damping force characteristics of the damping valves 51 and 61 can be corrected in accordance with the vibration on the damper case 11 side, and the response can be improved.

  (g) The means for adjusting the damping force of the damping valves 51 and 61 according to the vibration on the damper case 11 side is configured only by using the first and second springs 111 and 112 and the weight 120, and is simple. is there.

  (h) The vibration of the weight 120 caused by the vibration on the damper case 11 side immediately adjusts the valve opening pressure of the damping valves 51 and 61 via the first and second springs 111 and 112. Therefore, the damping force characteristics of the damping valves 51 and 61 can be quickly adjusted according to the vibration on the damper case 11 side.

  (i) The weight 120 includes first and second weights 121 and 122, and the first and second weights 121 and 122 are fitted to each other so as to be relatively movable along the axial direction of the cylinder 13. The first and second weights 121 and 122 are provided with a repulsion spring 124 that urges them in a direction away from each other along the axial direction of the cylinder 13. Is provided with a flow path 125 with a check valve and a flow path 126 with a throttle, which communicates the oil loading chamber 123 divided by the external weight housing chamber 110B.

  Here, the flow path 125 with the check valve allows the introduction of oil from the weight accommodating chamber 110B to the oil loading chamber 123 and allows the overall length of the first and second weights 121 and 122 to be enlarged. In the case of having 125A, the weight 120 is composed of first and second weights 121 and 122, and the first and second weights 121 and 122 are relatively movable along the axial direction of the cylinder 13. The first and second weights 121 and 122 repel each other in the direction of separating them from each other along the axial direction of the cylinder 13. A spring 124 is provided, and a flow path 125 with a check valve and a flow path 126 with a throttle are provided for communicating an oil loading chamber 123 divided by the two with an external weight housing chamber 110B.

  The higher the frequency of vibration on the damper case 11 side and the higher the acceleration acting on the first and second weights 121 and 122, the more the weights 121 and 122 have the repulsion spring 124 and the first or second spring 111. , 112 are relatively displaced in the direction in which the distance between them is increased. That is, the first and second weights 121 and 122 are not expanded or contracted due to the presence of oil loaded in the oil loading chamber 123 therebetween, but only in the direction of widening the distance between them due to the acceleration acting on them. At the same time, the oil introduced into the oil loading chamber 123 from the weight storage chamber 110B via the flow passage 125 with a check valve is repeatedly held by the restriction of the flow passage 126 with the throttle, and the interval is gradually increased. To do. When the distance between the first and second weights 121 and 122 is increased, the compression amount of the first and second springs 111 and 112 is increased, and consequently the valve opening pressures of the compression side damping valve 51 and the extension side damping valve 61 are increased. As a result, the maximum value of the compression side damping force and the maximum value of the extension side damping force are increased. Accordingly, as the damper case 11 (wheels) vibrates at a high frequency while the vehicle is traveling at high speed (the traveling speed is high), the distance between the first and second weights 121 and 122 is increased, and the damping force is increased. Running.

  The flow path 125 with a check valve that constitutes the damping force adjusting device 110 allows oil to be discharged from the oil loading chamber 123 to the weight housing chamber 110B, and the overall length L of the first and second weights 121 and 122. It is also possible to have a check valve that can reduce the size.

  In this case, as the frequency of vibration on the damper case 11 side becomes higher and the acceleration acting on the first and second weights 121 and 122 increases, the weights 121 and 122 become more effective against the repulsion spring 124 and the first or second. In a state of being sandwiched between the second springs 111 and 112, they are relatively displaced in a direction in which the distance between them is reduced. That is, the first and second weights 121 and 122 do not vibrate due to the presence of oil loaded in the oil loading chamber 123 therebetween, but only in a direction in which the distance between them is reduced by the acceleration acting on them. At the same time, the oil in the oil loading chamber 123 is discharged to the weight storage chamber 110B through the flow passage 125 with a check valve, and the oil in the oil loading chamber 123 is held by the restriction of the flow passage 126 with the restriction. Is repeated and the interval is gradually reduced. When the distance between the first and second weights 121 and 122 is reduced, the compression amount of the first and second springs 111 and 112 is reduced, and consequently the valve opening pressures of the compression side damping valve 51 and the extension side damping valve 61 are reduced. As a result, the maximum value of the compression side damping force and the maximum value of the extension side damping force are lowered.

  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. For example, the damping force generation device 40 includes an intermediate portion between the compression side damping valve 51 and the compression side check valve 52 (compression common flow) provided in the pressure side flow paths 50A and 60B of the first base piston 50 and the second base piston 60. The portion communicating with the passage 41) communicates with the oil reservoir 32, and the extension side damping valve 61 and the extension side provided in the extension side flow paths 50B and 60A of the first base piston 50 and the second base piston 60, respectively. The first base piston 50 is provided with a communication path 44 that communicates the intermediate portion of the check valve 62 (the portion that communicates with the pressure expansion shared flow channel 41) with the oil reservoir 32, or the first and second base pistons 50, 60 may be provided in both.

  Further, in the hydraulic shock absorber 100 (FIGS. 6 to 9), one of the first spring 111 and the second spring 112 may be removed from the damping force adjusting device 110. In this case, the damping force adjusting device 110 has the first spring 111 (or the second spring 112) and the weight 120, and the weight 120 is the first weight 121, the second weight 122, and the oil loading chamber 123. , A repulsion spring 124, a flow path with check valve 125, and a flow path with throttle 126. The first spring 111 (or the first weight 121) is seated on the back surface of the compression side damping valve 51, and the second weight 122 (or the second spring 112) is seated on the back surface of the extension side damping valve 61. According to this, although the effects (f), (g), and (h) are not achieved, the effects (i) are achieved.

  The present invention inserts a piston rod attached to the other of the vehicle body side and the axle side into a cylinder oil chamber of a damper case attached to one of the vehicle body side and the axle side, and uses a piston provided at the tip of the piston rod. The cylinder oil chamber is divided into a piston-side oil chamber and a rod-side oil chamber, and an oil reservoir chamber that compensates for the volume of the piston rod that advances and retreats into the cylinder oil chamber communicates with the cylinder oil chamber. In the hydraulic shock absorber in which a damping force generating device is provided between the chamber and the rod side oil chamber, the damping force generating device is fixed in two positions along the axial direction of the cylinder and is juxtaposed. A pressure-side damping valve provided in the pressure-side flow path provided in the first base piston; an extension-side damping valve provided in the extension-side flow path provided in the second base piston; Base piston A compression-side damping valve and an extension-side damping valve are arranged back-to-back inside the weight storage chamber partitioned inside the cylinder, and a first spring that biases the compression-side damping valve in the closing direction, and the extension-side damping valve in the closing direction A weight that vibrates along the axial direction of the cylinder is held between the second spring and the second spring. Accordingly, in the hydraulic shock absorber, the damping force characteristic can be quickly adjusted according to the vibration on the damper case side with a simple configuration.

10 Hydraulic shock absorber 11 Damper case 12 Damper tube 13 Damper cylinder 13A Outer cylinder 13B Inner cylinder 13C Outer flow path 14 Piston rod 25 Piston 27 Oil chamber 27A Piston side oil chamber 27B Rod side oil chamber 31 Air chamber 32 Oil reservoir chamber 40 Damping Force generators 41 to 43 Pressure expansion shared flow path 44 Communication path 50A Pressure side flow path 50B Extension side flow path 51 Pressure side damping valve 52 Pressure side check valve 60 Extension side piston 60A Extension side flow path 60B Pressure side flow path 61 Extension side attenuation valve 62 Extension side check valve 70 Bolt 80 Damping force adjusting device 80B Weight accommodating chamber 81 First spring 82 Second spring 83 Weight 100 Hydraulic shock absorber 110 Damping force adjusting device 110B Weight accommodating chamber 111 First spring 112 Second spring 120 Weight 121 First Weight 122 Second Weight 123 Oil Loading Chamber 124 Originating spring 125 check valve with flow path 126 throttle with flow paths

Claims (5)

Inserting a piston rod attached to the other of the vehicle body side and the axle side into the oil chamber of a cylinder provided in a damper case attached to one of the vehicle body side and the axle side,
A piston provided at the tip of the piston rod divides the cylinder oil chamber into a piston-side oil chamber and a rod-side oil chamber,
An oil reservoir chamber that compensates for the volume of the piston rod that advances and retreats into the cylinder oil chamber communicates with the cylinder oil chamber,
In the hydraulic shock absorber provided with a damping force generating device between the piston side oil chamber of the cylinder and the rod side oil chamber,
The damping force generator has first and second base pistons that are fixed and juxtaposed at two positions along the axial direction of the cylinder,
A pressure side damping valve is provided in the pressure side channel provided in the first base piston, an extension side damping valve is provided in the extension side channel provided in the second base piston,
A first spring in which a compression side damping valve and an extension side damping valve are arranged back to back inside the weight housing chamber in which the first and second base pistons are partitioned inside the cylinder, and the compression side damping valve is biased in the closing direction. And a second spring that biases the extension side damping valve in the closing direction, and holds a weight that vibrates along the axial direction of the cylinder. Inserting a piston rod attached to the other of the vehicle body side and the axle side into the oil chamber of a cylinder provided in a damper case attached to one of the vehicle body side and the axle side,
A piston provided at the tip of the piston rod divides the cylinder oil chamber into a piston-side oil chamber and a rod-side oil chamber,
An oil reservoir chamber that compensates for the volume of the piston rod that advances and retreats into the cylinder oil chamber communicates with the cylinder oil chamber
A damping force generator is installed between the piston side oil chamber of the cylinder and the rod side oil chamber,
Around the oil chamber of the cylinder in the damper case, an outer flow path that connects the piston-side oil chamber and the rod-side oil chamber is provided,
Damping force generator
In the pressure side stroke, a pressure side flow passage for flowing the oil in the piston side oil chamber of the cylinder from the outer flow passage of the cylinder toward the rod side oil chamber is provided in the damping force generator, and a pressure side damping valve is provided upstream of the pressure side flow passage. The pressure side check valve is provided on the downstream side, and the intermediate part of the pressure side damping valve and pressure side check valve provided in the pressure side flow path is communicated with the oil reservoir,
In the extension side stroke, an extension side flow channel is provided in the damping force generator for flowing the oil in the cylinder rod side oil chamber from the cylinder outer channel toward the piston side oil chamber. This is a hydraulic shock absorber in which an expansion side check valve is provided on the downstream side and an extension side check valve is provided on the downstream side, and an intermediate portion between the extension side attenuation valve and the extension side check valve provided in the extension side flow path is connected to the oil reservoir chamber. And
The damping force generator has first and second base pistons that are fixed and juxtaposed at two positions along the axial direction of the cylinder,
Each of the compression side damping valve and the extension side check valve is provided in each of the pressure side channel and the extension side channel provided in the first base piston, and each of the extension side channel and the pressure side channel provided in the second base piston. Each provided with an extension side damping valve and a compression side check valve,
A first spring in which a compression side damping valve and an extension side damping valve are arranged back to back inside the weight housing chamber in which the first and second base pistons are partitioned inside the cylinder, and the compression side damping valve is biased in the closing direction. And a second spring that biases the extension side damping valve in the closing direction, and holds a weight that vibrates along the axial direction of the cylinder. The weight comprises first and second weights;
The first and second weights are fitted to each other so as to be relatively movable along the axial direction of the cylinder, and define an oil loading chamber between the two,
The first and second weights are provided with repulsion springs that urge both of them in a direction away from each other along the axial direction of the cylinder, and a check valve that communicates an oil loading chamber defined by the both to an external weight housing chamber The hydraulic shock absorber according to claim 1 or 2, comprising an attached flow path and a restricted flow path.   The flow path with a check valve includes a check valve that allows oil to be introduced from the weight storage chamber into the oil loading chamber and allows the entire length of the first and second weights to be increased. The hydraulic shock absorber described.   The flow path with a check valve includes a check valve that allows oil to be discharged from the oil loading chamber to the weight storage chamber and can reduce the overall length of the first and second weights. The hydraulic shock absorber described.

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