JP2008309213A - Damping force generating structure for hydraulic shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a damping force generating structure for a hydraulic shock absorber wherein a choke passage is simply formed to generate damping force in a low speed region of a piston. <P>SOLUTION: The damping force generating structure comprises: a valve disc 2 for partitioning a cylinder filled with operating oil; a port 6a for communicating with oil chambers 3, 4 partitioned with the valve disc 2; and a laminated leaf valve 13 arranged by closing the port 6a, and bent and opened when a pressure difference between the oil chambers 3, 4 exceeds a predetermined value. The laminated leaf valve 13 is provided with: a first leaf valve 20 having a through-passage 20a communicating with the port 6a; a second leaf valve 22 laminated on the first leaf valve 20 via a spacer 21; and an annular sub leaf valve 23 arranged between the first leaf valve 20 and the second leaf valve 22 at a predetermined space from the spacer 21. Between the sub leaf valve 23 and the second leaf valve 22, the choke passage 26 is formed to guide operating oil to the oil chamber 4 on the downstream side. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a damping force generating structure for a hydraulic shock absorber.

  As a hydraulic shock absorber mounted on vehicles such as automobiles, when the piston speed is in the low speed range, the damping force characteristics in the low speed range are improved by generating a damping force in the choke passage. What to do is known.

A hydraulic shock absorber described in Patent Document 1 is a window leaf valve including a lower leaf valve supported on a spring seat, a leaf spacer having a radial cutout groove, and an orifice communicating with the cutout groove. The choke passage is configured by stacking these three leaf valves (see Patent Document 1 and FIG. 1).
JP 11-294515 A

  In the hydraulic shock absorber in Patent Document 1, depending on the degree of overlap between the leaf-shaped spacer and the window-side leaf valve, the connecting portion of the leaf-shaped spacer blocks the orifice of the window-side leaf valve, so that the flow path area changes. Therefore, in order to set the desired damping force characteristics, a great amount of labor is required when assembling the leaf-shaped spacer and the window-side leaf valve.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a damping force generation structure for a hydraulic shock absorber in which a choke passage that generates a damping force in a low piston speed range is simply configured. And

  The present invention provides a valve disk defining a cylinder filled with hydraulic oil, a port formed in the valve disk and communicating between oil chambers defined by the valve disk, and closing the port. A damping force generating structure of a hydraulic shock absorber, comprising a laminated leaf valve that bends and opens when a pressure difference between an upstream oil chamber and a downstream oil chamber exceeds a predetermined value, The laminated leaf valve includes a first leaf valve in which a through passage communicating with the port is formed, a second leaf valve laminated on the first leaf valve via a spacer, the first leaf valve, An annular sub-leaf valve disposed between the spacer and the second leaf valve at a predetermined interval; and between the sub-leaf valve and the first leaf valve or the second leaf valve, First Wherein the choke passage for introducing the hydraulic oil flowing from the through-passage leaf valve between the sub leaf valve and said spacer into the oil chamber of the downstream side is formed.

  According to the present invention, the hydraulic oil that passes through the passageway of the first leaf valve and flows into the region between the spacer and the sub leaf valve flows between the sub leaf valve and the first leaf valve or the second leaf valve. It passes through a choke passage formed therebetween and is led to an oil chamber on the downstream side. Since the structure for generating the damping force of the present invention is configured separately from the spacer disposed between the first leaf valve and the second leaf valve and the sub leaf valve, the first leaf valve, the spacer, The flow path area is not changed by assembling the two leaf valve and the sub leaf valve. Thus, the damping force generating structure for a hydraulic shock absorber according to the present invention has a simple choke path.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
With reference to FIG.1 and FIG.2, the damping force generation structure which is the 1st Embodiment of this invention is demonstrated. The damping force generation structure according to the first embodiment of the present invention is applied to the hydraulic shock absorber 100 shown in FIG. 1A is a cross-sectional view of the hydraulic shock absorber 100, FIG. 1B is a partially enlarged view of a region B in FIG. 1A, and FIG. 2 shows each leaf valve constituting the laminated leaf valve. It is sectional drawing. The cross section shown in FIG. 2 is a plane perpendicular to the axial direction.

  The hydraulic shock absorber 100 is interposed between a vehicle body and an axle in a vehicle such as an automobile, and has a function of suppressing a change in vehicle body posture.

  As shown in FIG. 1A, the hydraulic shock absorber 100 includes a cylindrical cylinder 1 in which hydraulic oil is sealed, and a slidable arrangement in the cylinder 1 and two oil chambers 3 and 4 in the cylinder 1. And a rod 5 that is fixed to one end and that extends to the outside of the cylinder 1 at the other end. In the first embodiment, the piston 2 corresponds to a valve disc.

  A gas chamber (not shown) is provided in the cylinder 1 to compensate for volume changes in the cylinder 1 due to the entry and exit of the rod 5.

  The piston 2 has a cylindrical core portion 2a through which the rod 5 is inserted, and an annular ring portion 2b that slides with the inner periphery of the cylinder 1 via a band 8 attached to the outer periphery. The ring portion 2b is formed to have a larger axial dimension than the core portion 2a. As a result, the piston 2 is formed with an accommodating portion 2c surrounded by the ring portion 2b.

  The piston 2 is formed with a plurality of inner peripheral ports 6 a that always communicate with the rod-side oil chamber 3 and a plurality of outer peripheral ports 6 b that always communicate with the oil chamber 4 on the opposite rod side. The hydraulic oil in the cylinder 1 moves back and forth between the oil chamber 3 and the oil chamber 4 via the inner peripheral port 6a and the outer peripheral port 6b. Specifically, the inner peripheral port 6 a is a flow path that guides hydraulic oil in the oil chamber 3 to the oil chamber 4 when the hydraulic shock absorber 100 is extended, and the outer peripheral port 6 b is when the hydraulic shock absorber 100 is compressed. This is a flow path for guiding the hydraulic oil in the oil chamber 4 to the oil chamber 3.

  An annular groove 2d in which hydraulic oil flowing out from the plurality of inner peripheral ports 6a joins is formed at the outlet of the inner peripheral port 6a in the piston 2, and a plurality of outer peripheral ports 6b are formed at the outlet of the outer peripheral port 6b. An annular groove 2e is formed in which the hydraulic oil that has flowed out of the tank joins.

  The band 8 is made of resin, and the piston 2 slides along the inner periphery of the cylinder 1 via the band 8, so that wear of the inner periphery of the cylinder 1 is suppressed, and the inner periphery of the cylinder 1 and the outer periphery of the piston 2 are The passage of hydraulic oil between the two is prevented and good sealing performance is obtained.

  The rod 5 has a rod body portion 5a and an inlay portion 5b which is formed on the distal end side and has a smaller diameter than the rod body portion 5a. Each member including the piston 2 is assembled to the inlay portion 5b.

  The member assembled | attached to the inlay part 5b is demonstrated.

  A step portion 5c is formed at the boundary between the rod main body portion 5a and the spigot portion 5b in the rod 5, and an annular valve stopper 10 is locked to the step portion 5c. The valve stopper 10 is formed with a plurality of through holes 10a through which hydraulic oil passes.

  The valve stopper 10 is disposed in contact with the inner peripheral side of the laminated leaf valve 12 via a spacer 11, and the piston 2 is disposed in contact with the laminated leaf valve 12. Thus, the laminated leaf valve 12 is disposed between the valve stopper 10 and the piston 2 so that the inner peripheral side thereof is supported and the annular groove 2e which is the outlet portion of the outer peripheral port 6b is closed.

  A laminated leaf valve 13 is accommodated in the accommodating portion 2c of the piston 2 in contact with the core portion 2a. On the inner peripheral side of the laminated leaf valve 13, a male screw portion 5d at the tip of the inlay portion 5b is screwed through a spacer 14. The mating nuts 15 are arranged in contact with each other. As described above, the laminated leaf valve 13 is supported between the piston 2 and the nut 15 on the inner peripheral side thereof, and is disposed so as to close the annular groove 2d that is the outlet portion of the inner peripheral port 6a.

  As described above, the valve stopper 10, the spacer 11, the laminated leaf valve 12, the piston 2, the laminated leaf valve 13, the spacer 14, and the nut 15 are sequentially inserted into the inlay part 5 b, and each of these members is inserted. Is fixed to the spigot part 5 b by tightening the nut 15. Note that the tip of the rod 5 is caulked in the shape shown by reference numeral 17 in order to prevent the nut 15 from coming off.

  The laminated leaf valves 12 and 13 are configured by laminating a plurality of annular leaf valves, and bend and open when the pressure difference between the upstream oil chamber and the downstream oil chamber exceeds a predetermined value. It is.

  Specifically, the laminated leaf valve 12 is arranged such that the inner peripheral side is supported and the free end side which is the outer peripheral side is seated on the seat portions 2f and 2h of the piston 2 and the outer peripheral port 6b is closed. Therefore, when the hydraulic shock absorber 100 is compressed and the pressure in the oil chamber 4 rises and the pressure difference between the oil chamber 3 and the oil chamber 4 exceeds a predetermined value, the outer peripheral side bends and opens. Thereby, a gap is generated between the laminated leaf valve 12 and the seat portions 2f and 2h, and a damping force is generated by the flow resistance generated when the hydraulic oil passes through the gap. Thus, the laminated leaf valve 12 is a damping valve for the compression stroke.

  Similarly, the laminated leaf valve 13 is also arranged such that the inner peripheral side is supported and the free end side, which is the outer peripheral side, is seated on the seat portion 2g of the piston 2 and the inner peripheral port 6a is closed. Therefore, when the hydraulic shock absorber 100 is extended, the pressure in the oil chamber 3 rises and the pressure difference between the oil chamber 3 and the oil chamber 4 exceeds a predetermined value, the outer peripheral side bends and opens. Thus, the laminated leaf valve 13 is a damping valve for the extension stroke. The laminated leaf valve 12 is formed with a through passage 12a for guiding hydraulic oil to the inner peripheral port 6a, and the inlet portion of the inner peripheral port 6a communicates the through passage 12a and the inner peripheral port 6a. An annular groove 2i is formed, and the inner peripheral port 6a is always in communication with the oil chamber 3 via the annular groove 2i and the through passage 12a.

  The laminated leaf valves 12 and 13 bend and open to generate a damping force when the piston speed is mainly in the middle to high speed range. Hereinafter, a damping force generating structure that generates a damping force in a low speed region where the piston speed before the laminated leaf valves 12 and 13 are bent will be described with reference mainly to FIGS. 1B and 2. In the following description, the laminated leaf valve 13 for the extension stroke will be described as an example.

  As shown in FIG. 1B, the laminated leaf valve 13 is configured by overlapping a plurality of annular leaf valves, and is a first leaf valve that is disposed while being seated on the seat portion 2 g of the piston 2. 20, a second leaf valve 22 stacked on the first leaf valve 20 via a spacer 21, and a sub-leaf valve 23 disposed between the first leaf valve 20 and the second leaf valve 22. .

  FIG. 2A is a cross-sectional view showing the first leaf valve 20. The first leaf valve 20 is formed with a plurality (four in the present embodiment) of circular through passages 20a communicating with the inner peripheral port 6a through the annular groove 2d on the same circumference.

  FIG. 2B is a cross-sectional view showing the spacer 21 and the sub leaf valve 23. The spacer 21 is for separating the first leaf valve 20 and the second leaf valve 22 by a predetermined distance, and is compressed by the first leaf valve 20 and the second leaf valve 22. Further, the spacer 21 is an annular member, and is arranged so that the inner periphery thereof is closely fitted to the outer periphery of the spigot part 5 b and the outer edge is not hung on the through passage 20 a of the first leaf valve 20. Is done. In this way, the spacer 21 is disposed on the inner peripheral side with respect to the through passage 20 a of the first leaf valve 20.

  The sub-leaf valve 23 is an annular member and is disposed so as to surround the spacer 21. Further, as shown in FIG. 1B, the sub leaf valve 23 is attached to the surface of the first leaf valve 20 so that the outer periphery forms the same surface as the outer periphery of the first leaf valve 20 and the second leaf valve 22. The inner edge of the first leaf valve 20 is not hung on the through passage 20a. As described above, the sub leaf valve 23 is disposed on the outer peripheral side of the through passage 20 a of the first leaf valve 20 and is disposed at a predetermined interval from the spacer 21. This predetermined interval is at least equal to or larger than the diameter of the through passage 20a of the first leaf valve 20. By separating the outer periphery of the spacer 21 from the inner periphery of the sub leaf valve 23 by a predetermined distance, an oil chamber 24 communicating with the through passage 20a of the first leaf valve 20 is defined between the two. The sub leaf valve 23 is formed to have a thickness smaller than that of the spacer 21. The sub-leaf valve 23 is attached to the first leaf valve 20 by laser welding or the like.

  As described above, the spacer 21 and the sub leaf valve 23 are configured separately, and there is no member for connecting the spacer 21 and the sub leaf valve 23. Therefore, an annular oil chamber 24 is defined between the spacer 21 and the sub leaf valve 23. Will be made. Therefore, no matter how the first leaf valve 20 is arranged, the through passage 20a communicates with the oil chamber 24, and the flow passage area of the through passage 20a does not change.

  FIG. 2C is a cross-sectional view showing the second leaf valve 22. Both surfaces of the second leaf valve 22 are formed to be smooth.

  Since the thickness of the sub leaf valve 23 is smaller than that of the spacer 21, the second leaf valve 22 is stacked via the spacer 21, so that the sub leaf valve 23 is operated between the sub leaf valve 23 and the second leaf valve 22. A choke passage 26 through which oil passes is formed.

  The choke passage 26 communicates with the oil chamber 24 and has an opening 26a on the outer peripheral surface of the laminated leaf valve 13, and communicates with the oil chamber 4 through the opening 26a. Therefore, the hydraulic oil that passes through the through passage 20 a of the first leaf valve 20 from the inner peripheral port 6 a and flows into the oil chamber 24 is guided to the oil chamber 4 by the choke passage 26. That is, the oil chamber 3 and the oil chamber 4 are always in communication.

  The passage width of the choke passage 26, that is, the distance between the sub leaf valve 23 and the second leaf valve 22 is determined by the difference in thickness between the spacer 21 and the sub leaf valve 23. That is, the passage width of the choke passage 26 is set by adjusting the thickness of the sub leaf valve 23 with respect to the spacer 21, and between the sub leaf valve 23 and the second leaf valve 22, both There is no need to provide a member for defining the interval. Therefore, the choke passage 26 is formed in an annular shape between the sub leaf valve 23 and the second leaf valve 22, and the flow passage area does not change due to the assembly of the spacer 21 and the second leaf valve 22.

  Next, the operation of the choke passage 26 will be described.

  When the piston speed is in the low speed region during the extension operation of the hydraulic shock absorber 100, the laminated leaf valve 13 does not bend, and the hydraulic oil is guided from the oil chamber 3 to the oil chamber 4 via the choke passage 26.

  Specifically, when the hydraulic shock absorber 100 is extended, the oil chamber 3 is compressed, so that the hydraulic oil in the oil chamber 3 flows through the through-passage 12a, the inner peripheral port 6a, the annular groove 2d, and the laminated leaf valve 12. The oil flows into the oil chamber 24 through the through passage 20 a of the first leaf valve 20. The choke passage 26 guides the hydraulic oil flowing into the oil chamber 24 to the oil chamber 4. Thus, when the hydraulic shock absorber 100 is extended, the oil chamber 3 is on the upstream side, and the oil chamber 4 is on the downstream side.

  Since the passage length of the choke passage 26 is longer than the cross-sectional area, a flow resistance is generated by the viscosity of the hydraulic oil when the hydraulic oil passes, thereby generating a damping force. As described above, since the damping force in the low speed region is generated by the fluid resistance of the choke passage 26, the damping force in the low speed region can be linearly increased in proportion to the piston speed. . Therefore, even when the expansion / contraction speed of the hydraulic shock absorber 100 is in the low speed range, the vertical vibration of the vehicle can be quickly attenuated, and the riding comfort can be improved.

  Other aspects of the first embodiment will be described below.

  In the above description, the sub leaf valve 23 is attached to the first leaf valve 20 on the upstream side, but the sub leaf valve 23 may be attached to the surface of the second leaf valve 22 on the downstream side. In this case, the choke passage 26 is formed between the first leaf valve 20 and the sub leaf valve 23.

  Further, the sub leaf valve 23 is not attached to any of the first leaf valve 20 and the second leaf valve 22 and is arranged in an unconstrained state, and as shown in FIG. A guide portion 27 for separating the sub leaf valve 23 and the spacer 21 by a predetermined distance may be provided on at least one of the outer circumferences of the spacer 21. Even with this configuration, the oil chamber 24 can be defined between the spacer 21 and the sub-leaf valve 23. FIG. 3 shows the case where the guide portion 27 is provided on the inner periphery of the sub-leaf valve 23.

  The guide portion 27 is disposed on the inner periphery of the sub leaf valve 23 or the outer periphery of the spacer 21 so as to face the other side, and prevents the sub leaf valve 23 from moving relative to the spacer 21. It is desirable to provide at least three places as shown. When the sub-leaf valve 23 and the spacer 21 are configured in this way, the choke passage 26 basically has the choke passage 26 between the first leaf valve 20 and the sub-leaf valve 23 and between the sub-leaf valve 23 and the second leaf valve 23. It is formed between the leaf valves 22.

  However, when the oil chamber 24 is defined using the guide portion 27, the guide portion 27 is caught on the through passage 20 a of the first leaf valve 20 depending on the arrangement of the first leaf valve 20, and the through passage 20 a. The flow path area of this will change (become small). Therefore, when the guide part 27 is used, it is necessary to form the guide part 27 as thin as possible and to have a minimum size.

  Moreover, as shown in FIG. 4, you may form the penetration path 20a of the 1st leaf valve 20 so that it may penetrate in an axial direction in circular arc shape. By forming the through passage 20a in an arc shape, the flow passage area of the through passage 20a can be increased. Thereby, the damping force generated when passing through the through passage 20a is minimized, and the influence on the damping force generated in the choke passage 26 is reduced.

  In the above description, the choke passage 26 is applied to the laminated leaf valve 13 for the extension stroke. However, the first leaf valve 20, the spacer 21, the second leaf valve 22, and the sub leaf valve 23 are compressed. Of course, the choke passage 26 can be applied to the laminated leaf valve 12.

  Furthermore, in the above description, the case where the damping force generating structure of the present invention is applied to the laminated leaf valves 12 and 13 that sandwich the piston 2 sliding in the cylinder 1 has been shown. However, the present invention is not limited to such an embodiment, and can also be applied to a laminated leaf valve that sandwiches a base valve (not shown) that is fixedly disposed on the bottom of the cylinder 1. is there.

  Specifically, the base valve further defines the oil chamber 4 on the side opposite to the rod in the cylinder 1 into two oil chambers, and the base valve is formed with a port communicating between the two oil chambers. . Then, the laminated leaf valve is arranged with the port of the base valve closed. This laminated leaf valve is bent and opened when the pressure difference between the two oil chambers exceeds a predetermined value. In this embodiment, the base valve corresponds to the valve disc.

  According to the first embodiment described above, the following effects can be obtained.

  Since the spacer 21 and the sub leaf valve 23 are configured separately and there is no member for connecting both, an annular oil chamber 24 is defined between the spacer 21 and the sub leaf valve 23. The passage width of the choke passage 26 is set by adjusting the thickness of the sub leaf valve 23 relative to the spacer 21, and defines the distance between the sub leaf valve 23 and the second leaf valve 22. There is no need to provide a member for this purpose.

  Therefore, no matter how the relative positions of the first leaf valve 20, the spacer 21, the second leaf valve 22, and the sub leaf valve 23 are set, the flow passage areas of the through passage 20a and the choke passage 26 change. There is no.

  In this way, the choke passage 26 is simply configured, and labor required for assembling the laminated leaf valves 12 and 13 is greatly reduced.

(Second Embodiment)
With reference to FIG.5 and FIG.6, the damping force generation structure which is the 2nd Embodiment of this invention is demonstrated. The damping force generation structure according to the second embodiment of the present invention is applied to the hydraulic shock absorber 200 shown in FIG. 5A is a cross-sectional view of the hydraulic shock absorber 100, FIG. 5B is a partially enlarged view of region B in FIG. 5A, and FIG. 6 is a view of each leaf valve constituting the laminated leaf valve. It is sectional drawing. Note that the cross section shown in FIG. 6 is a plane perpendicular to the axial direction.

  In the hydraulic shock absorber 200 according to the second embodiment, the same components as those of the hydraulic shock absorber 100 according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted. Below, it demonstrates centering on difference with the said 1st Embodiment.

  The member assembled | attached to the inlay part 5b is demonstrated.

  A cap 31 in which a passage 31a through which hydraulic oil passes is formed in the body portion is locked to the step portion 5c of the rod 5, and a cylindrical spacer 30 inserted into the spigot portion 5b is interposed in the cap 31. Is done.

  Inside the cap 31, an annular disk 32 that can slide along the outer periphery of the spacer 30 and a spring (biasing member) 33 that is compressed and disposed between the cap 31 and the disk 32 are accommodated. Is done.

  The disk 32 is formed with a plurality of first ports 34a through which hydraulic oil passes. The first port 34 a is a flow path that guides hydraulic oil in the oil chamber 3 to the oil chamber 4 when the hydraulic shock absorber 200 is extended. At the outlet of the first port 34a, an annular groove 32a is formed in which the hydraulic oil flowing out from the plurality of first ports 34a joins.

  The laminated leaf valve 13 that is bent and opened during the extension operation of the hydraulic shock absorber 200 is disposed in contact with the disk 32, and the piston 2 is disposed in contact with the outer peripheral side of the laminated leaf valve 13. And the nut 15 is screwed and arrange | positioned at the male thread part 5d of the tip of the inlay part 5b. By tightening the nut 15, each member is fixed to the spigot part 5 b of the rod 5.

  The laminated leaf valve 13 is supported on the outer peripheral side between the disc 32 and the piston 2, and the free end side, which is the inner peripheral side, is seated on the seat portion 32b of the disc 32 and is an annular portion that is the outlet portion of the first port 34a. The groove 32a is closed.

  Therefore, when the hydraulic shock absorber 200 extends and the pressure in the oil chamber 3 rises and the pressure difference between the oil chamber 3 and the oil chamber 4 exceeds a predetermined value, the laminated leaf valve 13 is bent and opened on the inner peripheral side. I speak. Thereby, a gap is generated between the laminated leaf valve 13 and the seat portion 32b, and a damping force is generated by the flow resistance generated when the hydraulic oil passes through the gap.

  As described above, the second embodiment releases hydraulic oil from the inner peripheral side of the laminated leaf valve 13. In this respect, hydraulic oil is released from the outer peripheral side of the laminated leaf valve 13. This is different from the first embodiment.

  A plurality of second ports 34b through which hydraulic oil passes are formed in the piston 2, and the hydraulic oil that has passed through the opening of the laminated leaf valve 13 is guided to the oil chamber 4 through the second port 34b.

  Note that, when the hydraulic shock absorber 200 is compressed, the pressure in the oil chamber 4 increases, so that the laminated leaf valve 13 presses the disk 32 against the urging force of the spring 33. Thereby, the disk 32 and the laminated leaf valve 13 move along the outer periphery of the spacer 30, the laminated leaf valve 13 is separated from the end surface of the piston 2, and the second port 34 b and the passage 31 a of the cap 31 communicate with each other. Thereby, the hydraulic oil in the oil chamber 4 is guided to the oil chamber 3.

  Hereinafter, a leaf valve constituting the laminated leaf valve 13, that is, a damping force generation structure that generates a damping force in a low speed region of the piston will be described mainly with reference to FIGS. 5B and 6. 6A is a cross-sectional view showing the first leaf valve 20, FIG. 6B is a cross-sectional view showing the spacer 21 and the sub leaf valve 23, and FIG. 6C is the second leaf valve 22. FIG.

  As shown in FIG. 6, the damping force generating structure of the second embodiment has a spacer 21 and a sub leaf valve 23 arranged between the first leaf valve 20 and the second leaf valve 22 as described above. This is different from the damping force generation structure of the first embodiment.

  Specifically, the arrangement of the spacer 21 and the sub leaf valve 23 is opposite to that of the first embodiment, and the spacer 21 is arranged so as to surround the sub leaf valve 23.

  The spacer 21 is formed so that the inner edge does not reach the through passage 20 a of the first leaf valve 20, and is disposed on the outer peripheral side of the through passage 20 a of the first leaf valve 20. Further, the sub leaf valve 23 is formed such that the outer edge does not reach the through passage 20 a of the first leaf valve 20, and is disposed on the inner peripheral side of the through passage 20 a of the first leaf valve 20.

  Therefore, an annular choke passage 26 formed between the sub leaf valve 23 and the second leaf valve 22 communicates with an oil chamber 24 defined between the spacer 21 and the sub leaf valve 23, and An opening 26 a is provided on the inner peripheral surface of the laminated leaf valve 13.

  As described above, the second embodiment has the opening 26 a on the inner peripheral surface of the laminated leaf valve 13. In this respect, the second embodiment has the opening 26 a on the outer peripheral surface of the laminated leaf valve 13. This is different from the first embodiment.

  The opening 26a of the choke passage 26 communicates with the oil chamber 4 via the second port 34b. As described above, the choke passage 26 communicates with the oil chamber 24 and also communicates with the oil chamber 4 through the opening 26a.

  Therefore, the hydraulic oil that passes through the through passage 20 a of the first leaf valve 20 from the first port 34 a and flows into the oil chamber 24 is guided to the oil chamber 4 by the choke passage 26. That is, the oil chamber 3 and the oil chamber 4 are always in communication.

  When the piston speed is in the low speed region during the extension operation of the hydraulic shock absorber 100, the laminated leaf valve 13 does not bend, and the hydraulic oil is guided from the oil chamber 3 to the oil chamber 4 via the choke passage 26.

  Specifically, the hydraulic oil in the oil chamber 3 flows into the oil chamber 24 through the passage 31 a of the cap 31, the first port 34 a, the annular groove 32 a, and the through passage 20 a of the first leaf valve 20. The choke passage 26 guides the hydraulic oil flowing into the oil chamber 24 to the oil chamber 4, and when the hydraulic oil passes, a damping force is generated by the flow resistance due to the viscosity of the hydraulic oil.

  Also in the hydraulic shock absorber 200 according to the second embodiment configured as described above, the same operational effects as the hydraulic shock absorber 100 in the first embodiment are exhibited.

  In the second embodiment, the disk 32 and the piston 2 correspond to the valve disk.

  In the second embodiment, the choke passage 26 is applied to the laminated leaf valve 13 for the extension stroke. However, the choke passage 26 can also be applied to the laminated leaf valve for the compression stroke. is there. In this case, the laminated leaf valve for the compression stroke is arranged on a base valve (valve disk) arranged fixed to the bottom of the cylinder 1.

  Similarly to the first embodiment, the sub leaf valve 23 is attached to the surface of the second leaf valve 22 on the downstream side, and the choke passage 26 is formed between the first leaf valve 20 and the sub leaf valve 23. You may comprise.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  The present invention can be applied to a shock absorber mounted on a vehicle.

(A) It is sectional drawing which shows the hydraulic shock absorber 100 in the 1st Embodiment of this invention. (B) It is the elements on larger scale of the area | region B in Fig.1 (a). It is sectional drawing of each leaf valve which comprises a lamination leaf valve. It is sectional drawing which shows the other aspect of the subleaf valve in a lamination | stacking leaf valve. It is sectional drawing which shows the other aspect of the 1st leaf valve in a lamination | stacking leaf valve. (A) It is sectional drawing which shows the hydraulic shock absorber 200 in the 2nd Embodiment of this invention. (B) It is the elements on larger scale of the area | region B in Fig.5 (a). It is sectional drawing of each leaf valve which comprises a lamination leaf valve.

Explanation of symbols

100, 200 Hydraulic shock absorber 1 Cylinder 2 Piston 2f, 2g Seat part 3, 4 Oil chamber 5 Rod 6a Inner peripheral port 6b Outer peripheral port 12, 13 Laminated leaf valve 20 First leaf valve 20a Through passage 21 Spacer 22 Second leaf Valve 23 Sub-leaf valve 24 Oil chamber 26 Choke passage 26a Opening portion 32 Disc 32b Seat portion 34a First port 34b Second port

Claims (6)

A valve disk defining a cylinder filled with hydraulic oil;
A port formed in the valve disc and communicating between oil chambers defined by the valve disc;
Damping force of a hydraulic shock absorber provided with a laminated leaf valve that is arranged with the port closed and bends and opens when the pressure difference between the upstream oil chamber and the downstream oil chamber exceeds a predetermined value Generating structure,
The laminated leaf valve is
A first leaf valve formed with a through passage communicating with the port;
A second leaf valve stacked on the first leaf valve via a spacer;
An annular sub-leaf valve disposed between the first leaf valve and the second leaf valve with a predetermined distance from the spacer;
Between the sub leaf valve and the first leaf valve or the second leaf valve, the hydraulic oil flowing between the spacer and the sub leaf valve from the through passage of the first leaf valve A structure for generating damping force of a hydraulic shock absorber, wherein a choke passage leading to a downstream oil chamber is formed. The sub-leaf valve is formed with a thickness smaller than the spacer,
2. The damping force generating structure for a hydraulic shock absorber according to claim 1, wherein the passage width of the choke passage is set by adjusting a thickness of the sub leaf valve with respect to the spacer. 3. The laminated leaf valve has an inner peripheral side supported and an outer peripheral side seated on a seat portion of the valve disc,
The spacer is disposed on the inner peripheral side with respect to the through path of the first leaf valve,
3. The structure for generating a damping force of a hydraulic shock absorber according to claim 1, wherein the sub-leaf valve is disposed on an outer peripheral side of the through-passage of the first leaf valve. The laminated leaf valve is supported while the outer peripheral side is supported and the inner peripheral side is seated on the seat portion of the valve disc,
The spacer is arranged on the outer peripheral side of the through-passage of the first leaf valve,
3. The structure for generating a damping force of a hydraulic shock absorber according to claim 1, wherein the sub leaf valve is arranged on an inner peripheral side of the through path of the first leaf valve. 4.   The structure for generating a damping force of a hydraulic shock absorber according to any one of claims 1 to 4, wherein the sub leaf valve is attached to the first leaf valve or the second leaf valve. The sub leaf valve is disposed in an unconstrained state with respect to the first leaf valve and the second leaf valve,
The damping force of the hydraulic shock absorber according to any one of claims 1 to 4, wherein at least one of the sub leaf valve and the spacer is provided with a guide portion that separates the sub leaf valve and the spacer by a predetermined distance. Occurrence structure.

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