JP4726079B2 - Buffer valve structure - Google Patents

Description

  The present invention relates to an improved valve structure of a shock absorber.

  Conventionally, this kind of shock absorber valve structure is embodied in, for example, a piston portion of a shock absorber for a vehicle, and an annular leaf valve is laminated on the outlet end of a port provided in the piston portion. A valve that opens and closes a port is known.

  In particular, in the above-described shock absorber valve structure in which the inner periphery of the leaf valve is fixedly supported and the port is opened and closed by bending the outer peripheral side, the damping force in the medium and high speed regions becomes too large in the vehicle. In order to solve this problem, the inner periphery of the leaf valve L may not be fixedly supported and the inner periphery of the leaf valve L may be connected to the piston rod R or the piston P as shown in FIG. Has been proposed in which a valve structure of a shock absorber is slidably brought into contact with the outer periphery of a cylindrical piston nut N fixed to the piston rod R and the back surface of the leaf valve L is urged by a spring S through a main valve M. In the figure, it is embodied in the expansion side damping valve of the shock absorber (see, for example, Patent Document 1).

In this valve structure, as shown in the drawing, when the piston speed when the piston P moves upward is in a low speed region, the outer peripheral side of the leaf valve L is a fulcrum on the contact portion of the main valve M stacked on the leaf valve L. As shown in FIG. 5, the hydraulic oil that exhibits substantially the same damping characteristics as the valve structure in which the inner periphery is fixedly supported and passes through the port Po when the piston speed reaches the middle-high speed region. Acts on the leaf valve L, and the leaf valve L lifts in the axial direction from the piston P together with the main valve M against the urging force of the spring S, so that the inner periphery is fixedly supported. Compared with the valve structure of the vessel, the flow path area is increased and the damping force is suppressed from being excessive, so that the riding comfort in the vehicle can be improved.
JP-A-9-291196 (FIG. 1)

  However, in the proposed valve structure as described above, although it is a useful technique in terms of improving riding comfort in a vehicle, it may be pointed out that there are the following problems.

  This is because, for example, when the piston speed when the piston P moves upward reaches the high speed region, in the conventional shock absorber valve structure, the leaf valve L moves backward from the piston P in the axial direction according to the piston speed. The damping coefficient does not increase.

  Therefore, when the piston speed reaches the high speed region, the damping force is insufficient, and the vibration is not sufficiently suppressed, so that the riding comfort in the vehicle is deteriorated.

  Therefore, the present invention was devised to improve the above problems, and the object of the present invention is to improve the riding comfort in the vehicle even when the piston speed reaches the high speed region. It is to provide a valve structure of a shock absorber.

In order to solve the above-described object, the problem solving means in the present invention includes a valve disk in which a port is formed, a shaft member rising from a shaft center part of the valve disk, and an outer periphery of the shaft member so as to be in sliding contact with the outer periphery. And an annular leaf valve that is stacked on the valve disk and closes the port; an annular valve holding member that is inserted into the outer periphery of the shaft member and is in sliding contact with the outer periphery; and that is stacked on the leaf valve; and in the direction of closing the port in the valve structure of the damper provided with a biasing means for biasing the leaf valve via the valve restraining member, and gives the direction of thrust faces the biasing force of the biasing means to the valve suppressing member by at least the internal pressure upper pressure chamber volume is expanded or contracted with the sliding of the valve restraining member, the internal pressure of the port to bypass the leaf valve It is characterized in that provided a passage leading to the pressure chamber.

According to the valve structure of the shock absorber of the present invention, when the piston speed reaches the high speed region, the force to push down the leaf valve and the valve restraining member of the hydraulic oil increases and the volume of the pressure chamber increases, but it passes through the passage. As the flow speed of the hydraulic fluid increases and the dynamic pressure drops, the pressure in the pressure chamber decreases as the piston speed increases, and the pressure rise in the pressure chamber cannot catch up. The rate of increase of the resultant force of retracting the leaf valve and the resultant force of the pressure chamber thrust with respect to the piston speed is smaller than the rate of increase of the resultant force with respect to the piston speed when the piston speed is in the medium speed region.
In other words, when the piston speed is in the high speed range, the gap between the disc valve and the leaf valve becomes difficult to increase as the piston speed increases, and the damping coefficient is higher than when the piston speed is in the medium speed range. Even when the piston speed reaches the high speed region, the damping force is not insufficient, vibration is sufficiently suppressed, and the riding comfort in the vehicle can be improved.

  Furthermore, in a situation where the amplitude at which the shock absorber is fully extended and the piston speed reaches the high speed region, the damping coefficient can be increased to increase the damping force generated by the shock absorber. Therefore, the piston speed can be quickly reduced, and the impact at the maximum extension can be reduced.

  The valve structure of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a part of a piston portion of a shock absorber in which a valve structure according to an embodiment is embodied. FIG. 2 is a diagram illustrating a damping characteristic in a shock absorber in which the valve structure of the shock absorber according to the embodiment is embodied. FIG. 3 is a longitudinal sectional view of a part of a piston portion of a shock absorber in which the valve structure of the shock absorber according to another embodiment is embodied.

  As shown in FIG. 1, the valve structure of the shock absorber in one embodiment is embodied as an extension side damping valve of the piston portion of the shock absorber, and includes a piston 1 as a valve disk in which a port 2 is formed, and a piston A piston nut 4 and a spacer 6 which are shaft members rising from the shaft center portion 1; an annular leaf valve 10 which is stacked on the piston 1 and closes the port 2 when the piston nut 4 is inserted on the inner peripheral side; An annular valve restraining member 11 stacked on the valve 10, a coil spring 15 as an urging means for urging the leaf valve 10 via the valve restraining member 11 in the direction of closing the port 2, and the valve restraining by internal pressure. A pressure chamber 16 that gives thrust to the member 11 in a direction opposite to the urging force of the urging means, and a passage 17 that guides the internal pressure of the port 2 to the pressure chamber 16. It is configured to include a.

  On the other hand, a shock absorber in which the valve structure is embodied is well known and will not be described in detail, but specifically, for example, a cylinder 40 and a head member (not shown) that seals the upper end of the cylinder 40. ), A piston rod 5 slidably penetrating a head member (not shown), the piston 1 provided at the end of the piston rod 5, an upper chamber 41 defined by the piston 1 in the cylinder 40, and a lower A chamber 42, a sealing member (not shown) for sealing the lower end of the cylinder 40, and an air chamber or a reservoir (not shown) that compensates for a change in the volume in the cylinder corresponding to the volume of the piston rod 5 protruding from the cylinder 40. The cylinder 40 is filled with a fluid, specifically, hydraulic oil.

  In the valve structure, when the piston 1 moves upward in FIG. 1 with respect to the cylinder 40, the pressure in the upper chamber 41 rises and the hydraulic oil flows from the upper chamber 41 to the lower chamber 42 via the port 2. , The leaf valve 10 provides resistance to the movement of the hydraulic oil to cause a predetermined pressure loss, thereby functioning as a damping force generating element that generates a predetermined damping force in the shock absorber.

  Hereinafter, the valve structure will be described in detail. The piston 1 serving as a valve disc is formed in a bottomed cylindrical shape, and an insertion hole 1b through which the piston rod 5 of the shock absorber is inserted into the axial center portion of the bottom 1a, a port 2, A window 3 communicating with the port 2 and a valve seat 1c formed on the outer peripheral side of the window 3 serving as an outlet end of the port 2 are provided. The piston 1 is provided with a pressure-side port 1d that allows a flow of hydraulic oil from the lower chamber 42 to the upper chamber 41 when the shock absorber contracts, on the outer peripheral side from the port 2 on the extended side of the bottom 1a. It has been.

The piston rod 5 is inserted into the insertion hole 1b of the piston 1 as described above, and the tip of the piston rod 5 is projected downward in FIG. Although not shown, the outer diameter of the distal end of the piston rod 5, as well as the piston rod R of a conventional shock absorber shown in FIG. 4, is set smaller in diameter than the outer diameter of the upper side (not shown), the upper side A step portion (not shown) is formed in a portion where the outer diameters of the tip portion and the tip portion are different.

Subsequently, a piston nut 4 forming part of the shaft member has a tubular portion 4a, is configured with a flange 4b extending from the lower end outer periphery in Fig. 1, Tangaishu on the cylindrical portion 4a is a small diameter Thus, a small diameter portion 4c is formed.

  The tip of the piston rod 5 is inserted into the insertion hole 1b of the piston 1 together with a pressure-side leaf valve (not shown), a valve stopper, etc. (not shown), and a cylindrical shape forming a part of the shaft member. The spacer 6 is attached to the piston rod 5 from the lower side of the piston 1 in FIG. 1, and the piston nut 4 is screwed onto the screw portion 5a provided at the tip of the piston rod 5 from the lower side of the spacer 6 in FIG. The piston 1 is fixed to the piston rod 5 by being sandwiched between the step of the piston rod 5 and the upper end of the piston nut 4 via the spacer 6.

  In addition, the lower end opening part in the insertion hole 1b provided in the bottom part 1a of the piston 1 is enlarged in diameter, and a step part is formed, and the upper end in FIG. 1 of the spacer 6 can be inserted into this step part. In addition, a communication hole 1f is provided for communicating the enlarged diameter portion 1e of the insertion hole 1b with the port 2.

  And the above-mentioned spacer 6 is cylindrical, The notch 6a along an axial direction is provided in the outer periphery, This notch 6a is in the state inserted in the enlarged diameter part 1e of the piston 1, It communicates with the communication hole 1f and communicates with the port 2 through the communication hole 1f.

Further, the outer diameter of the spacer 6, where the illustrated, is formed on the outer diameter and the same diameter of the portion other than the small diameter portion 4c of the tubular portion 4a of the piston nut 4, the shaft member with the spacer 6 and the piston nut 4 is formed In addition, the small-diameter portion 4c of the piston nut 4 is a recess provided in the side portion of the shaft member. Therefore, in the case of this embodiment, the recess is formed in an annular groove shape along the circumferential direction of the shaft member, and the port 2 is communicated with the notch 6a.

  As described above, by making the piston 1 have a bottomed cylindrical shape, the length from the upper end of the piston 1 (not shown) to the lower end of the piston nut 4 can be reduced, and the piston portion can be downsized. However, the shape of the piston 1 is not limited to this.

  Also, a plurality of annular spacers 7 having a smaller diameter than the leaf valve 10 are stacked on the bottom 1a of the piston 1 so as to be in sliding contact with the outer periphery of the spacer 6, and the leaf that is also in sliding contact with the outer periphery of the spacer 6 from below the spacer 7 is stacked. A plurality of annular spacers 8 that are smaller in diameter than the leaf valve 10 and are in sliding contact with the outer periphery of the spacer 6 are stacked from the lower side of the leaf valve 10, and further below the spacer 8. In the same manner, a valve holding member 11 slidably contacting the outer periphery of the spacer 6 is laminated.

  The leaf valve 10 is formed in an annular shape, and the upper surface in FIG. 1 is brought into contact with the valve seat 1c so that the port 2 of the piston 1 can be closed. Further, although not shown in detail, a notch formed on the outer periphery of the leaf valve 10 seated on the valve seat 1c or a known orifice formed by being stamped on the valve seat 1c is provided.

  And the valve | bulb holding | suppressing member 11 laminated | stacked in the lowest lowest part in FIG. 1 is a cylinder part 11b, the collar 11a extended from the upper outer periphery of the cylinder part 11b, and inner side from the inner peripheral side lower end of the cylinder part 11b. A flange portion 11c extending in the direction, and the inner periphery of the flange portion 11c is in sliding contact with the outer periphery of the small diameter portion 4c of the piston nut 4. That is, the flange portion 11c of the valve restraining member 11 described above is a convex portion that is slidably inserted into the concave portion of the shaft member, and the flange portion 11c, the spacer 6, and the small diameter portion 4c that become the convex portion. The pressure chamber 16 is partitioned by the recess formed by

  The inner periphery of the cylindrical portion 11b of the valve pressing member 11 is in sliding contact with the outer periphery of the spacer 6, and a passage 17 is formed by a flow path formed by the notch 6a and the inner periphery of the valve pressing member 11 and the communication hole 1f. The pressure chamber 16 communicates with the port 2 through the passage 17. Note that the number of the passages 17 is not limited to one, and a plurality of the notches 6a may be provided.

  As described above, a part of the passage 17 is formed by the notch 6a and the inner periphery of the valve restraining member 11, so that the fine processing that provides the passage 17 inside the thickness of the spacer 6 is strong. Therefore, the processing of the passage 17 is very simple.

  In the above description, the pressure chamber 16 is partitioned as described above. However, when the pressure chamber 16 is not annular, for example, the concave portion is formed as a vertical groove along the axial direction of the piston nut 4 to suppress the valve. Compared to the case where the member 11 is provided with a convex portion to be inserted into the longitudinal groove to partition the pressure chamber, the concave portion is formed into an annular groove shape and the convex portion is formed into a flange portion 11c, and the shape of the pressure chamber 16 is formed into an annular shape. Accordingly, the pressure chamber 16 can be communicated with the port 2 through the passage 17 without requiring the circumferential alignment of the spacer 6 and the piston nut 4, and the assembling process is facilitated.

  A coil spring 15 as an urging means is interposed between the flange 11a and the flange 4b of the piston nut 4. The leaf spring 10 is pressed against the valve seat 1c by the coil spring 15.

  That is, the urging force of the coil spring 15 is applied to the inner peripheral side of the leaf valve 10 through the valve restraining member 11, and the leaf valve 10 is urged in the direction of closing the port 2 by the coil spring 15.

  Therefore, when the piston 1 moves upward in FIG. 1 and the difference between the pressure in the upper chamber 41 and the pressure in the lower chamber 42 becomes large, the leaf valve 10 causes the coil spring 15 to resist the urging force. The entire leaf valve 10 is compressed and retracted in the axial direction from the piston 1, that is, lifted downward in FIG.

  The leaf valve in which the axial thickness of the entire spacer 7 is set shorter than the axial length from the bottom 1a of the piston 1 to the lower end of the valve seat 1c, and the urging force acts on the inner peripheral side. 10 is given an initial deflection.

  By setting the deflection amount of the initial deflection, the valve opening pressure when the leaf valve 10 leaves the valve seat 1c and opens the port 2 can be adjusted. The deflection amount of the initial deflection is the entire amount of the spacer 7. The thickness is set so as to be optimal for a vehicle to which a shock absorber is applied. The spacer 7 can be omitted depending on the axial length from the bottom 1a of the piston 1 to the lower end of the valve seat 1c.

  Further, in the above description, the urging means is the coil spring 15. However, since a predetermined urging force may be applied to the leaf valve 10, this may be, for example, a disc spring or a leaf spring, or an elastic material such as rubber. It may be a body.

  Further, the number of leaf valves 10 may be arbitrary depending on the damping characteristics realized by the present valve structure. For example, a plurality of leaf valves 10 may be used, and the outer diameter of the leaf valve 10 may be arbitrarily set. Can do.

  Next, the operation of the valve structure will be described. As described above, when the piston 1 moves upward in FIG. 1 with respect to the cylinder 40, the pressure in the upper chamber 41 is increased, and the hydraulic oil in the upper chamber 41 is increased. It tries to move into the lower chamber 42 through the port 2.

  When the piston speed is in the low speed region, the hydraulic oil is formed by stamping the notch provided on the outer periphery of the leaf valve 10 seated on the valve seat 1c or the valve seat 1c when the piston speed is extremely low. The outer periphery of the leaf valve 10 is bent as the speed increases thereafter, and passes through the gap between the leaf valve 10 and the valve seat 1c. In this case, the pressure in the port 2 acts on the leaf valve 10 and is also guided into the pressure chamber 16 via the passage 17, and the pressure chamber 16 gives a thrust in a direction in which the valve restraining member 11 is retracted from the piston 1. That is, thrust is applied in a direction opposite to the direction opposite to the urging force of the coil spring 15, but the urging force of the coil spring 15 prevails, and the leaf valve 10 resists the urging force of the coil spring 15 and the piston 1. The leaf valve 10 is urged by the coil spring 15 to be pressed so as to close the port 2 and is bent only with the outer peripheral edge of the spacer 8 as a fulcrum.

  The damping characteristics (relationship of the damping force with respect to the piston speed) at this time are as shown in FIG. 2, and the damping coefficient is relatively large in this low speed region.

  On the other hand, when the speed of the piston 1 reaches the medium speed region and the difference between the pressure in the upper chamber 41 and the pressure in the lower chamber 42 is equal to or greater than a predetermined value, the hydraulic oil leaf valve 10 is pushed downward in FIG. As the force increases, the pressure in the pressure chamber 16 also increases and the thrust applied to the valve restraining member 11 increases, and the force and thrust overcome the urging force of the coil spring 15, so that the entire leaf valve 10 is moved to the piston 1. 1 is moved backward in the axial direction, that is, moved downward in FIG.

  At this time, the entire leaf valve 10 is separated from the bottom 1a of the piston 1, and the gap between the valve seat 1c and the leaf valve 10 is larger than when the piston speed is in the low speed region, and is proportional to the piston speed. Therefore, the damping characteristic when the piston speed is in the middle speed region is as shown in FIG. 2 and is proportional to the increase in the piston speed, but the damping coefficient is lower than the low speed region. The slope of the attenuation characteristic becomes small.

When the piston speed reaches the high speed region, the force of pushing down the hydraulic oil leaf valve 10 and the valve restraining member 11 downward in FIG. 1 increases, and the volume of the pressure chamber 16 increases , but the operation through the passage 17 increases. As the flow rate of oil increases and the dynamic pressure decreases , the pressure in the pressure chamber 16 decreases as the piston speed increases, and the pressure increase in the pressure chamber 16 cannot catch up.
Then, when the piston speed is in the high speed region, the rate of increase of the force by which the hydraulic oil retracts the leaf valve 10 and the resultant force of the thrust of the pressure chamber 16 with respect to the piston speed is relative to the piston speed when the piston speed is in the medium speed region. It becomes smaller than the increase rate of the resultant force.

That is, when the piston speed is in the middle speed region , the increase rate of the retraction amount from the piston 1 of the leaf valve 10 to the piston speed is the retraction amount of the leaf valve 10 from the piston 1 in the case where the piston speed is in the high speed region. Smaller than the rate of increase with respect to piston speed.

  That is, when the piston speed is in the high speed region, the clearance between the valve seat 1c and the leaf valve 10 becomes difficult to increase as the piston speed increases, and the damping characteristic when the piston speed is in the high speed region. As shown in FIG. 2, since the attenuation coefficient becomes larger than that in the medium speed region, the inclination becomes large.

  Therefore, in the valve structure of the shock absorber in the present embodiment, when the piston speed reaches the high speed region, the damping coefficient can be made larger than when the piston speed is in the medium speed region, and the piston speed is high. Even when reaching the region, the damping force is not insufficient, vibration is sufficiently suppressed, and the riding comfort in the vehicle can be improved.

  Furthermore, in a situation where the amplitude at which the shock absorber is fully extended and the piston speed reaches the high speed region, the damping coefficient can be increased to increase the damping force generated by the shock absorber. Therefore, the piston speed can be quickly reduced, and the impact at the maximum extension can be reduced.

  The piston speed at which the damping coefficient increases can be set by adjusting the passage area and length of the passage 17, and when the piston speed is set to be a boundary between the medium speed region and the high speed region, the piston speed When the is in the middle speed range, the damping coefficient can be kept relatively small, so that the damping force does not become too large and the riding comfort in the vehicle can be ensured. Specifically, when the boundary between the medium speed region and the high speed region of the piston speed at which the damping coefficient increases is set to, for example, 0.6 m / s or more and 2 m / s or less, the shock absorber is applied. This is suitable for an actual vehicle and the practicality is improved.

 Next, the valve structure of the shock absorber in another embodiment will be described. As shown in FIG. 3, the valve structure of the shock absorber in this other embodiment is such that the depth of a part of the notch 6a of the spacer 6 is made shallow, so that the valve structure of the shock absorber in one embodiment is provided. It is only different. Accordingly, the other configuration is the same as that shown in FIG. 1, and in the description of the present embodiment, the same reference numerals are given to the same components as those of the shock absorber valve structure in the first embodiment. Therefore, detailed description thereof will be omitted, and only different parts will be described in detail.

  As described above, in the shock absorber valve structure according to the other embodiment, as shown in FIG. 3, the depth of a part of the notch 6a of the spacer 6 is shallow. A part of the passage 17 is formed by the notch 6a and the inner periphery of the cylindrical portion 11b of the valve holding member 11 in the same way as the valve structure of the shock absorber according to the embodiment. This embodiment differs from the first embodiment in that an orifice 18 is formed in the passage 17 between the shallow portion of the notch 6a and the inner periphery of the cylindrical portion 11b of the valve holding member 11 described above. .

  In addition, even if the valve | bulb holding | suppressing member 11 moves to the axial direction with respect to the spacer 6 which makes a part of shaft member, the shallow part of this notch 6a continues to oppose the inner periphery of the cylinder part 11b. Formed in position. Therefore, the orifice 18 does not fail due to the movement of the valve holding member 11 in the axial direction.

  Further, since the orifice 18 is formed by making a part of the notch 6a shallow, even if the valve restraining member 11 rotates in the circumferential direction with respect to the spacer 6, it can function as an orifice. In addition, there is no need to position the valve holding member 11 in the circumferential direction with respect to the spacer 6, and the assembly process is facilitated.

  And in the valve structure of the shock absorber in this other embodiment, the pressure in the port 2 is guided into the pressure chamber 16 by the passage 17 in the same manner as the valve structure of the shock absorber in one embodiment. However, the transmission of the pressure becomes a first order delay depending on the vibration frequency of the piston 1 in the vertical direction.

  That is, as the vibration frequency in the vertical direction of the piston 1 becomes higher, the increase in the internal pressure of the pressure chamber 16 is delayed, and the thrust for retracting the valve restraining member 11 is also delayed with respect to the vibration of the piston 1. Therefore, as the vibration frequency of the piston 1 becomes higher, the thrust applied to the valve restraining member 11 by the pressure chamber 16 is suppressed.

  When the vibration frequency of the piston 1 described above is high, the stroke length is limited and the actual shock absorber is in use in parallel with the suspension spring interposed between the vehicle body and the axle of the vehicle. Since the piston speed is in the high speed region, the retraction amount of the leaf valve 10 from the piston 1 when the piston speed is in the middle region even in the shock absorber valve structure in the other embodiments. The rate of increase with respect to the piston speed is smaller than the rate of increase of the retraction amount of the leaf valve 10 from the piston 1 with respect to the piston speed when the piston speed is in the high speed region.

  That is, when the piston speed is in the high speed region, the clearance between the valve seat 1c and the leaf valve 10 becomes difficult to increase as the piston speed increases, and the damping characteristic when the piston speed is in the high speed region. As shown in FIG. 2, since the attenuation coefficient becomes larger than that in the medium speed region, the inclination becomes large.

  Therefore, even in the valve structure of the shock absorber in other embodiments, when the piston speed reaches the high speed region, the damping coefficient can be made larger than when the piston speed is in the medium speed region, and the piston speed is Even in the case of reaching the high speed region, the damping force is not insufficient, vibration is sufficiently suppressed, and the riding comfort in the vehicle can be improved.

  Furthermore, in a situation where the amplitude at which the shock absorber is fully extended and the piston speed reaches the high speed region, the damping coefficient can be increased to increase the damping force generated by the shock absorber. Therefore, the piston speed can be quickly reduced, and the impact at the maximum extension can be reduced.

  In each of the embodiments described above, the piston 1 is fixed by the piston nut 4. However, when the piston 1 can be fixed to the piston rod 5 by another means, the coil spring 15 in FIG. If a member that supports the lower end is provided, a recess may be provided with the piston rod 5 as a shaft member, and the leaf valve 10 and the valve holding member 11 may be in direct sliding contact with the outer periphery of the piston rod 5. Further, the piston rod 5 is protruded by providing an insertion hole 1a in the piston 1 and inserting the tip of the piston rod 5, but a shaft member that is integral with or separate from the piston 1 that is a valve disk is used as the piston. You may make it provide in the axial center part of 1. FIG.

  The passage 17 is constituted by the notch 6 a provided in the spacer 6, the inner periphery of the valve holding member 11 and the communication hole 1 f in each of the embodiments described above, but a part of the passage is formed inside the piston rod 5. And the passages inside the piston rod 5 may be communicated with the port 2 and the recess of the shaft member, respectively.

  This is the end of the description of the embodiment of the valve structure, but the valve structure of the present invention can be embodied in the compression side damping valve of the piston portion of the shock absorber, or in the base valve portion. Of course, the present invention can be applied to a valve of a shock absorber that functions as a damping force generating element that generates a damping force.

 It should be noted that the scope of the present invention is not limited to the details shown or described.

It is a longitudinal cross-sectional view in a part of piston part of the shock absorber by which the valve structure of the shock absorber in one embodiment was embodied. It is a figure which shows the damping characteristic in the buffer which embodied the valve | bulb structure of the buffer of one Embodiment. It is a longitudinal cross-sectional view in a part of piston part of the shock absorber by which the valve structure of the shock absorber in other embodiment was embodied. It is a longitudinal cross-sectional view of the piston part of the buffer which actualized the valve structure of the conventional buffer. It is a figure which shows the damping characteristic in the buffer which actualized the valve structure of the conventional buffer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Piston 1a which is a valve disc Bottom 1b Insertion hole 1c Valve seat 1d, 2 Port 1e Diameter expansion part 1f Communication hole 3 Window 4 Piston nuts 4a and 11b which are shaft members 4c, 11a 鍔 4c Small diameter part 4d Step part 5 Piston rod 5a Screw part 6 Spacer 6a Notch 7, 8 Spacer 10 Leaf valve 11 Valve restraining member 11c Flange part 15 Coil spring 16 as urging means Pressure chamber 17 Passage 18 Orifice 40 Cylinder 41 Upper chamber 42 Lower chamber

Claims (6)

A valve disk in which a port is formed, a shaft member rising from an axial center portion of the valve disk, an annular leaf valve which is inserted into the outer periphery of the shaft member so as to be in sliding contact with the outer periphery and which is stacked on the valve disk and closes the port An annular valve pressing member that is inserted into the outer periphery of the shaft member and is in sliding contact with the outer periphery and is laminated on the leaf valve; and a biasing unit that biases the leaf valve through the valve pressing member in the direction of closing the port; In the valve structure of the shock absorber provided with the above, at least a pressure in the direction opposite to the urging force of the urging means is applied to the valve holding member by the internal pressure, and the volume expands or contracts as the valve holding member slides. the shock absorber valve, characterized the pressure chamber, in that a a passage for guiding the internal pressure of the port to the pressure chamber, bypassing the leaf valve Elephants.     The pressure chamber is defined by a concave portion provided on a side portion of the shaft member and a convex portion slidably inserted into a concave portion of the shaft member provided on the inner peripheral side of the valve holding member. The shock absorber valve structure according to claim 1.     3. The shock absorber valve according to claim 2, wherein the concave portion is an annular groove provided on a side portion of the shaft member, and the convex portion is an annular flange portion provided on an inner peripheral side of the valve holding member. Construction.     4. The valve structure for a shock absorber according to claim 1, wherein an orifice is provided in the middle of a passage for guiding the internal pressure of the port to the pressure chamber.     5. A part of the passage for guiding the internal pressure of the port to the pressure chamber is formed by a notch formed on the outer periphery of the shaft member and communicated with the recess, and an inner periphery of the valve holding member. The valve structure of the shock absorber according to any one of the above.     6. The shock absorber valve structure according to claim 5, wherein the orifice is formed by reducing a depth of a part of the notch.

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