JP5517337B2 - Buffer valve structure - Google Patents

Description

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

  Conventionally, in this kind of shock absorber valve structure, for example, it is embodied in the piston portion of the shock absorber built in the front fork of the two-wheeled vehicle, and the outlet end of the port provided in the piston is an annular leaf valve. The leaf valve is biased toward the piston side by a coil spring (see, for example, Patent Document 1).

  Specifically, in the valve structure of the shock absorber described above, a leaf valve is slidably mounted on the outer periphery of a piston holder that passes through the axial center portion of the piston and holds the piston, and the leaf valve is axially moved with respect to the piston. When the pressure of the hydraulic oil acting on the front side of the leaf valve increases, the coil spring is compressed and the leaf valve moves backward from the piston to open the port greatly.

  By adopting such a configuration, the port in a region where the piston speed is relatively high compared to a valve structure in which the port is opened by fixing and supporting the inner periphery of the leaf valve and bending the outer periphery of the leaf valve. Can be greatly opened, and the damping force during the compression stroke can be prevented from becoming excessive, and the riding comfort in the vehicle can be improved.

Japanese Patent Laying-Open No. 2003-247484 (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.

  The conventional valve structure employs a configuration in which the leaf valve is energized with a coil spring, making it difficult to produce a coil spring with a uniform natural length and spring constant, and generating and damping a shock absorber that embodies the valve structure. There is a risk that the force varies from product to product.

  In addition, when the valve structure described above is used for the piston part of the shock absorber built in the front fork, it is necessary to avoid increasing the size of the piston part from the viewpoint of mounting in a narrow front fork and securing the stroke length of the shock absorber. Under the conditions that the coil spring radial size and compression length are significantly limited, the coil spring wire diameter cannot be increased, and the leaf valve may not be provided with sufficient urging force. .

  For example, when the compression speed is in the low speed range, even if an attempt is made to generate a damping force according to the piston speed by bending only the outer periphery without lifting the leaf valve, the compression speed is actually in the low speed range. However, the coil spring is compressed, the leaf valve lifts from the piston, and the port is greatly opened, so that the compression side damping force in the low speed region is insufficient unlike the intended purpose of the designer.

  Also, if the vibration direction of the shock absorber reverses from the compressed state to the extension direction from the compressed state of the coil spring, the port must be closed quickly with a leaf valve, but if the biasing force of the coil spring is insufficient, There is a delay in the closing operation of the leaf valve, the pressure side chamber and the extension side chamber are maintained in communication with each other at the port, and the damping force immediately after the shock absorber is switched from the compression stroke to the extension stroke is insufficient. Things will also happen.

  The present invention was devised in order to improve the above-mentioned problems, and the object of the present invention is to provide a shock absorber valve structure capable of generating a stable damping force and generating a sufficient damping force in a low speed range. Is to provide.

In order to solve the above object, the valve structure of the shock absorber in the problem solving means of the present invention includes a valve disk having a port formed in the shock absorber and communicating with one chamber and the other chamber, and a valve disk. A piston holder connected to the piston rod, an annular leaf valve that is axially movable on the valve disc and opens and closes the outlet end of the port, and a leaf spring that biases the leaf valve toward the valve disc in the valve structure of the damper having, with the piston holder and the base portion, a shaft portion which the valve disc is mounted rises from the center of the base and a flange erected toward the top periphery of the base to the leaf valve, the A leaf valve, a leaf spring, and a spacer that is interposed between the leaf valve and the leaf spring and whose outer diameter is set smaller than the leaf spring are slid on the outer periphery of the shaft portion. Freely mounted, the outer periphery of the counter-valve disk side of the leaf spring is supported by the collar, the spacer and the flange, characterized in that it is exhibited biasing force to maintain the deflected state the leaf spring at all times.

  In the valve structure of the shock absorber according to the present invention, the leaf valve that opens and closes the port is urged by a leaf spring having a small individual difference in the spring constant, so a coil spring is used as the urging means. Compared with the conventional valve structure, the variation of the generated damping force in the shock absorber for each product can be suppressed.

  Also, even if the number of laminated annular plates constituting the leaf spring is increased or the leaf spring is thickened in order to set a large spring constant in the leaf spring, it does not become long in the axial direction. Therefore, since enlargement of the piston portion can be avoided, a sufficient urging force can be applied to the leaf valve without sacrificing the stroke length of the shock absorber.

  Therefore, by setting the initial load by the leaf spring as appropriate, when the piston speed is in the low speed range, the leaf valve is not lifted and only the outer periphery of the leaf valve is deflected to reduce the damping force according to the piston speed. And a sufficient damping force in the low speed region can be generated in the shock absorber.

  In addition, since the leaf valve can be sufficiently energized by the leaf spring, when the vibration direction of the shock absorber is switched, the leaf valve can be quickly returned to the position where the port is closed, and the expansion / contraction stroke is reduced. The damping force generated by the shock absorber immediately after switching is not insufficient.

  Therefore, according to the valve structure of the shock absorber of the present invention, a stable damping force can be generated in the shock absorber, and a sufficient damping force can be generated even when the expansion / contraction speed of the shock absorber is in a low speed range. Can do it.

It is a longitudinal cross-sectional view in the piston part in which the valve structure of the shock absorber in one embodiment was embodied. It is the figure which applied the buffer which embodied the valve structure of the buffer in one embodiment to a front fork. It is a longitudinal cross-sectional view in the base valve part in which the valve structure of the shock absorber in other embodiments was embodied. It is the figure applied to the front fork in which the valve structure of the shock absorber in one embodiment was embodied.

  The valve structure of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the valve structure of the shock absorber in one embodiment is embodied as a damping valve on the pressure side of the piston portion of the shock absorber D, and is slidably inserted into the cylinder 1. As a valve disc having a pressure side chamber R1 as one chamber formed inside and an extension side chamber R2 as the other chamber, and a pressure side port 2a as a port for communicating the pressure side chamber R1 and the extension side chamber R2 A piston 2, an annular leaf valve 3 that is axially movable on the extension side chamber R2 side of the piston 2 and opens and closes the outlet end of the port 2a, and an energization that biases the leaf valve 3 toward the piston 2 It comprises a leaf spring 4 as a biasing means.

  On the other hand, the shock absorber D in which the valve structure is embodied is applied to a front fork F interposed between a vehicle body (not shown) and a front wheel axle of a saddle-ride type vehicle such as a two-wheeled vehicle as shown in FIG. Specifically, the cylinder 1, the piston 2 that is slidably inserted into the cylinder 1 to form the compression side chamber R1 and the expansion side chamber R2, and the upper end of the cylinder 1 in FIG. A reservoir cylinder 10 that is connected to form a reservoir R therein and a piston rod 11 that is movably inserted into the cylinder 1 and connected to the piston 2 are provided. Is filled with hydraulic oil.

  The piston 2 has an annular shape and includes an expansion side port 2b in addition to the compression side port 2a described above. The compression side chamber R1 and the expansion side chamber R2 are communicated with each other by the compression side and the expansion side ports 2a and 2b. .

  The pressure side port 2a is opened and closed by a leaf valve 3 stacked on the lower end of the piston 2 in FIG. 1, and the leaf valve 3 prevents the flow of hydraulic oil from the extension side chamber R2 toward the pressure side chamber R1. The flow of hydraulic oil from the compression side chamber R1 to the extension side chamber R2 is given resistance.

  On the other hand, the expansion side port 2b is opened and closed by a leaf valve 12 stacked on the upper end of the piston 2 in FIG. 1, and the leaf valve 12 allows the flow of hydraulic oil from the compression side chamber R1 to the expansion side chamber R2. While blocking, resistance is given to the flow of the hydraulic fluid which goes to the compression side chamber R1 from the expansion side chamber R2.

  In the reservoir R, an air chamber 14 and an oil chamber 15 are partitioned by a free piston 13, and the oil chamber 15 is filled with hydraulic oil in the same manner as the cylinder 1. The free piston 13 is urged downward in FIG. 2 by a spring 17 interposed between the free piston 13 and a sealing member 16 that closes the upper end of the reservoir cylinder 10. Is pressurized.

  Further, the shock absorber D includes a partition member 18 that partitions the pressure side chamber R1 formed in the cylinder 1 and the oil chamber 15 provided in the reservoir R, and a port 18a provided in the partition member 18, The pressure side chamber R1 and the oil chamber 15 are communicated with each other through 18b.

  One port 18a is opened and closed by a leaf valve 19 provided at the upper end of the partition member 18, and the leaf valve 19 prevents the flow of hydraulic oil from the oil chamber 15 toward the pressure side chamber R1. At the same time, resistance is given to the flow of liquid from the pressure side chamber R1 to the oil chamber 15. That is, in the shock absorber D, the partition member 18 and the leaf valve 19 constitute a base valve.

  The other port 18b is configured to be opened and closed by a check valve 20 provided at the lower end of the partition member 18. The check valve 20 prevents the flow of hydraulic oil from the pressure side chamber R1 to the oil chamber 15, Only the flow of liquid from the oil chamber 15 toward the pressure side chamber R1 is allowed.

  The shock absorber D thus configured has a telescopic type in which the upper end in FIG. 2 of the reservoir cylinder 10 is coupled to the outer tube 21 of the front fork F and the lower end of the piston rod 11 is coupled to the inner tube 22 of the front fork F. The piston rod 11 is set in a so-called inverted type in which the piston rod 11 is disposed below the cylinder 1.

  A suspension spring 23 arranged in parallel with the shock absorber D is interposed between the outer tube 21 and the inner tube 22, and this suspension spring 23 urges the front fork F in the extending direction, and the front fork F When the vehicle is interposed between the axle of the motorcycle and the vehicle body, the vehicle body is elastically supported.

  When the inner tube 22 is extended with respect to the outer tube 21 in the front fork F, the leaf valve 12 causes the hydraulic oil to flow from the expansion side chamber R2 to the compression side chamber R1 via the expansion side port 2b of the piston 2. A resistance is applied to cause a predetermined pressure loss, and a predetermined extension side damping force is generated in the shock absorber D. During this extension operation, the check valve 20 is opened, and the volume of hydraulic oil in which the piston rod 11 is withdrawn from the cylinder 1 is supplied from the oil chamber 15 into the cylinder 1 via the port 18b to compensate for the volume in the cylinder 1. Is made.

  On the other hand, during the compression operation in which the inner tube 22 intrudes into the outer tube 21 in the front fork F, the volume of hydraulic oil that the piston rod 11 enters into the cylinder 1 becomes excessive in the cylinder 1 and passes through the port 18a. The oil is discharged from the cylinder 1 to the oil chamber 15, and resistance is given to the flow of the hydraulic oil by the leaf valve 19 to increase the pressure in the cylinder 1. In the case of the shock absorber D, during the compression operation, the damping force on the compression side is generated in the shock absorber D mainly by the pressure increase in the cylinder 1 by the leaf valve 19, but in the valve structure of the present invention, the pressure side port of the piston 2 The leaf valve 3 applies resistance to the flow of hydraulic oil from the compression side chamber R1 to the expansion side chamber R2 via 2a, and this leaf valve 3 generates a differential pressure between the compression side chamber R1 and the expansion side chamber R2. At least, it acts to increase the damping force on the compression side of the shock absorber D and contributes to the generation of the compression side damping force of the shock absorber D.

  Hereinafter, the valve structure contributing to the generation of the compression side damping force as described above will be described in detail. The leaf valve 3 has an annular shape, is stacked on the lower end of the piston 2 in FIG. 1, and is slidably mounted on the outer periphery of a piston holder 24 that is a shaft member that connects the piston 2 to the piston rod 11. The leaf valve 3 is urged toward the piston 2 by a leaf spring 4 disposed below the leaf valve 3 in FIG.

  The leaf valve 3 in this embodiment is configured as a laminated leaf valve by laminating a plurality of annularly formed plates. The number of the annular plates is a damping characteristic (piston) realized by this valve structure. The relationship between the damping force and the speed may be arbitrary, and may be plural or only one depending on the damping characteristics generated in the shock absorber D. Also, as shown, the damping generated in the shock absorber D Depending on the characteristics, the outer diameter of each plate can be set differently.

  The piston holder 24 includes a top cylindrical base portion 24a that is screwed to the tip of the piston rod 11, a shaft portion 24b that rises from the top portion of the base portion 24a and is mounted with the piston 2, and a top portion and a shaft portion 24b of the base portion 24a. 1, a lateral hole 24 d that opens from the side of the top of the base portion 24 a and communicates with the vertical hole 24 c, and a flange 24 e that is provided on the outer periphery of the top end of FIG. Configured. And the eaves 24e are made into the shape which protrudes an outer peripheral side toward the upper direction in FIG.

  The shaft holder 24 b of the piston holder 24 includes an annular stopper 25, an annular leaf spring 4, an annular spacer 26, a leaf valve 3, a piston 2, a leaf valve 12, and a valve stopper 27 that regulates the amount of bending of the leaf valve 12. Are assembled in order from the bottom in the figure.

  Specifically, a step portion 24f is provided on the shaft portion 24b of the piston holder 24, and the upper portion in FIG. 1 is set to a small diameter from the step portion 24f. The piston 2, the leaf valve 12, and the valve stopper 27 are step portions. The shaft portion 24b is mounted on the small diameter side of the shaft portion 24b above 24f, and is sandwiched between the step portion 24f and the piston nut 28 screwed to the tip of the shaft portion 24b, and fixed to the piston holder 24 so as not to move. Is done. On the other hand, the leaf spring 4, the spacer 26, and the leaf valve 3 are mounted below the stepped portion 24f of the shaft portion 24b, and are movable in the axial direction on the shaft portion 24b.

  As described above, the leaf spring 4 is annular, and is attached to the shaft portion 24b of the piston holder 24 and below the stepped portion 24f. It is set so as to be in sliding contact with the portion 24b. Further, the outer periphery of the plate spring 4 on the side opposite to the piston is in contact with the outer periphery of the flange 24e of the piston holder 24, and is supported by the flange 24e from the lower side in FIG. Since it is not fixed to the portion 24b and is in sliding contact, it can be bent downward in FIG. 1 with the inner peripheral side as a free end. In this embodiment, the leaf spring 4 is formed by laminating a plurality of annular plates, and the spring constant can be adjusted by the number of laminated annular plates. Even if the spring constant is increased, the leaf spring 4 does not increase in size in the radial direction and hardly increases in the axial direction. Therefore, it can be applied without difficulty in the shock absorber D having a small piston diameter. The number of annular plates can be set to an arbitrary number according to the spring constant, and may be singular. The spring constant may be set by adjusting the plate thickness.

  Further, the leaf spring 4 does not necessarily have its inner periphery slidably contacted with the outer periphery of the shaft portion 24b of the piston holder 24. However, as in this embodiment, the inner periphery is the outer periphery of the shaft portion 24b in an unloaded state. When the leaf valve 3 is seated on the piston 2 and the amount of bending of the leaf spring 4 is only the initial deflection, the amount of bending of the leaf spring 4 is small and the inner circumference of the leaf spring 4 Since the gap formed between the shaft portion 24b and the shaft portion 24b is small, even if the leaf spring 4 is eccentric in the radial direction with respect to the shaft portion 24b, the amount of eccentricity is extremely small. Therefore, even if the leaf valve 3 retreats from the piston 2 and returns to the original position and is repeatedly seated on the piston 2, the amount of eccentricity with respect to the shaft portion 24b of the leaf spring 4 becomes small. The urging force to be urged is not greatly biased in the circumferential direction, and even if the lift of the leaf valve 3 from the piston 2 is repeated, the damping characteristic does not change each time, and the stable damping characteristic Can be obtained.

  Returning, the spacer 26 interposed between the leaf spring 4 and the leaf valve 3 has an annular shape, and, like the leaf spring 4, is a shaft portion 24b and is in sliding contact with the lower side of the step portion 24f. The outer diameter is set smaller than the outer diameter of the leaf spring 4 and the leaf valve 3. The spacer 26 and the flange 24e maintain the leaf spring 4 in a constantly bent state and exert an urging force. The attachment of the leaf spring 4 to the inner peripheral side of the leaf valve 3 through the spacer 26 is performed. Power is acting. As described above, the spacer 26 transmits the urging force of the leaf spring 4 to the leaf valve 3 and exerts the urging force by imparting initial deflection to the leaf spring 4, and the axial length (thickness) of the spacer 26. With this setting, the initial deflection amount of the leaf spring 4 can be adjusted. In order to facilitate this adjustment, the spacer 26 is configured by laminating a plurality of annular plates, but may be configured by a single annular plate.

  The spacer 26 can also move in the axial direction which is the vertical direction with respect to the shaft portion 24 b of the piston holder 24, similarly to the leaf spring 4 and the leaf valve 3. Accordingly, when the leaf valve 3 receives a force in the direction away from the piston 2 downward in FIG. 1 due to the pressure in the pressure side chamber R1 acting via the pressure side port 2a, and the force exceeds the urging force of the leaf spring 4. The leaf valve 3 moves away from the piston 2 and moves downward together with the spacer 26 so that the inner peripheral side of the leaf spring 4 can be bent downward.

  When the plate spring 4 is bent by a predetermined amount, the inner periphery of the side surface opposite to the piston of the plate spring 4 comes into contact with the stopper 25 fitted to the outer periphery of the shaft portion 24b, and further bending of the plate spring 4 is restricted. In addition, the separation (retraction) of the leaf valve 3 from the piston 2 is also restricted. That is, the stopper 25 not only regulates the amount of bending of the leaf spring 4, but also regulates the lift amount (retraction amount) of the leaf valve 3 from the piston 2, and the axial length (thickness) of the stopper 25. ) Can be adjusted to adjust both the amount of bending of the leaf spring 4 and the amount of lift of the leaf valve 3 from the piston 2. Since the stopper 25 is not particularly required to move with respect to the shaft portion 24b, the stopper 25 may be integrated with the shaft portion 24b.

  1 is provided with a groove 25a leading from the inner periphery to the outer periphery, and even if the leaf spring 4 abuts against the stopper 25, the upper end of the base 24a in the leaf spring 4 and the piston holder 24 is provided. And the space formed by the flange 24e is not sealed, so that the bending of the leaf spring 4 and the backward movement of the leaf valve 3 are not hindered. If the groove 25a is not provided in the stopper 25 as described above, a cutout or a hole may be provided in the leaf spring 4, the flange 24e, or the base portion 24a to avoid sealing the space.

  Then, as described above, the stopper 25, the leaf spring 4, the spacer 26, the leaf valve 3, the piston 2, the leaf valve 12, and the valve stopper 27 are sequentially assembled to the piston holder 24, and assembled as a piston portion. When the base portion 24 a of the holder 24 is screwed to the tip of the piston rod 11, the assembled piston portion is connected to the piston rod 11.

  In the shock absorber D, a needle-type valve element 29 is accommodated in the piston holder 24, and the needle-type valve 29 is disposed with respect to the annular valve seat 30 provided in the middle of the vertical hole 24c. By making the distance closer, the flow path area in the bypass path that bypasses the compression side and extension side ports 2a and 2b formed by the vertical hole 24c and the horizontal hole 24d can be changed.

  The needle type valve element 29 is connected or abutted to a control rod 31 inserted into the hollow piston rod 11 while being urged by a coil spring 32 in a direction away from the annular valve seat 30. By operating the control rod 31 externally, the needle type valve element 29 can be moved away from the annular valve seat 30 to adjust the flow path area in the bypass passage. When the control rod 31 and the needle type valve element 29 are integrated, the coil spring 32 can be omitted. Since the bypass path bypasses the compression side and extension side ports 2a, 2b, the damping force on the extension side and the compression side of the shock absorber D can be adjusted by adjusting the flow path area. The adjustment can be performed from the outside of the front fork F.

  Next, the operation of the valve structure configured as described above will be described. When the moving speed (piston speed) of the piston 2 with respect to the cylinder 1 is low during the compression stroke of the front fork F, the pressure in the pressure side chamber R1 acts on the leaf valve 3 via the pressure side port 2a and is pushed down. Although force is applied, it is pressed against the piston 2 side by the urging force of the leaf spring 4, and this urging force cannot be overcome, and the leaf valve 3 does not lift from the piston 2 but bends the outer periphery to compress the pressure side port. 2a will be opened. In this state, when the damping coefficient of the front fork F is high and the piston speed is in the low speed range, the damping force quickly rises and a good riding comfort can be obtained.

  On the other hand, when the piston speed increases, the pressure in the pressure side chamber R1 acting on the leaf valve 3 increases, and the force that pushes the leaf valve 3 downward overcomes the urging force of the leaf spring 4. As the spring 4 is bent, the leaf valve 3 is lifted from the piston 2 to greatly open the compression side port 2a.

  In this state, the damping coefficient of the front fork F is lower than when the piston speed is low. When the piston speed is in the high speed range, the damping force during the compression stroke does not become excessive, and You can improve your comfort.

  In the valve structure described above, the leaf valve 3 that opens and closes the compression side port 2a is urged by the leaf spring 4 having a small individual difference in the spring constant. Therefore, a coil spring is used as the urging means. As compared with the conventional valve structure, the variation of the generated damping force in the shock absorber D for each product can be suppressed. Furthermore, the variation can be minimized by the number of laminated annular plates constituting the leaf spring 4.

  Further, even if the number of stacked annular plates constituting the plate spring 4 is increased or the plate thickness of the plate spring 4 is increased in order to set a large spring constant in the plate spring 4, it becomes long in the axial direction. Since there is no such thing, the enlargement of the piston portion can be avoided, so that a sufficient urging force can be applied to the leaf valve 3 without sacrificing the stroke length of the shock absorber D.

  Therefore, by setting the initial load by the leaf spring 4 appropriately, when the piston speed in the compression stroke is in the low speed range, only the outer periphery of the leaf valve 3 is bent without lifting the leaf valve 3, and the piston A damping force corresponding to the speed can be generated, and the damping force on the compression side in the low speed region can be sufficiently generated in the shock absorber D.

  Further, since the leaf valve 3 can be sufficiently urged by the leaf spring 4, when the vibration direction of the shock absorber D is reversed from the compression direction to the extension direction, the leaf valve 3 is quickly closed by the pressure side port 2a. And the damping force immediately after the shock absorber D is switched from the compression stroke to the expansion stroke does not become insufficient.

  Therefore, according to the valve structure described above, a stable damping force can be generated in the shock absorber D, and a sufficient damping force can be generated even when the expansion / contraction speed of the shock absorber D is in a low speed range. It is.

  Further, even if the spring constant of the leaf spring 4 is set to a large value, it does not increase in size in the axial direction and the radial direction, so that it is suitable for a shock absorber having a small piston diameter. Optimal for damping valve on the pressure side of D.

 In the above description, the shock absorber D includes the base valve. However, it is also possible to adopt a configuration in which this is eliminated and the damping force on the compression side is generated only by the leaf valve 3 in the valve structure described above. is there.

 Furthermore, in the present embodiment, the shock absorber D is applied to the front fork F, but the valve structure of the present invention is naturally applicable to other than the shock absorber D applied to the front fork F. Even when applied to the front fork F, it may be arranged upside down instead of upside down instead of upside down.

  Further, in this embodiment, the piston 2 is connected to the piston rod 11 via the piston holder 24. However, when the piston 2 is directly connected to the piston rod 11, the shaft member is connected to the piston rod. 11 may be attached to the outer periphery of the piston rod 11.

  Further, the valve structure of the present invention may be provided on the pressure side chamber R1 side of the piston 2 so that the valve structure of the present invention can be embodied as an extension side damping valve of the piston portion of the shock absorber D.

  Further, the valve structure of the present invention can be embodied in a base valve portion as shown in FIG. The valve structure of the shock absorber according to another embodiment embodied in the damping valve on the pressure side of the base valve portion is fitted to the end portion of the cylinder 41 of the front fork F1 as a shock absorber, so that one chamber in the cylinder 41 is fitted. The pressure side chamber R3 and the reservoir R4 as the other chamber provided between the cylinder 41 and the inner tube 42 are partitioned, and a pressure side port 43a as a port for communicating the pressure side chamber R3 and the reservoir R4 is provided. A partition member 43 as a valve disk, an annular leaf valve 44 that is axially movable on the reservoir R4 side of the partition member 43 and opens and closes the outlet end of the pressure side port 43a, and the leaf valve 44 on the partition member 43 side And a leaf spring 45 as an urging means for urging toward the wing.

  On the other hand, as shown in FIG. 4, the front fork F <b> 1 as a shock absorber in which the valve structure is embodied is specifically inserted into the cylinder 41 and slidable in the cylinder 41 so as to be compressed in the cylinder 41. The piston 46 that forms the chamber R3 and the extension side chamber R5, the inner tube 42 that covers the outer periphery of the cylinder 41 and forms the reservoir R4 between the cylinder 41, and the piston 46 that is movably inserted into the cylinder 41 And a piston rod 47 connected to the piston rod 47, and a telescopic front fork having an outer tube 48 connected to the piston rod 47 and into which the inner tube 42 is slidably inserted. The inside and the reservoir R4 are filled with, for example, hydraulic oil as a fluid. Even in the front fork F1, like the front fork F, it is interposed between the vehicle body (not shown) of the saddle-ride type vehicle and the front wheel axle so as to suppress the relative movement between the vehicle body and the axle. It has become.

  The piston 46 is provided with passages 46a and 46b that are annular and communicate with the pressure side chamber R3 and the extension side chamber R5. The passage 46a is opened and closed by a leaf valve 60 stacked on the lower end of the piston 46 in FIG. The leaf valve 60 prevents the flow of hydraulic oil from the compression side chamber R3 to the expansion side chamber R5 and provides resistance to the flow of hydraulic oil from the expansion side chamber R5 to the compression side chamber R3. ing.

  On the other hand, the passage 46b is opened and closed by a check valve 49 stacked on the upper end of the piston 46 in FIG. 4, and the check valve 46 prevents the flow of hydraulic oil from the extension side chamber R5 to the pressure side chamber R3. At the same time, the passage 46b is opened with almost no resistance applied to the flow of hydraulic oil from the compression side chamber R3 to the extension side chamber R5.

  In addition, a diaphragm 50 fixed to the outer periphery of the cylinder 41 is accommodated in the reservoir R4, and an air chamber G is defined between the diaphragm 50 and the cylinder 41, and the gas sealed in the air chamber G is stored in the reservoir R4. The inside of the reservoir R4 is pressurized by the pressure.

  4 is fitted to the lower end in FIG. 4 of the cylinder 41, and the partition member 43 is held by a holder 51 that is screwed to the inner periphery of the lower end in FIG. Yes. The holder 51 is screwed to the inner tube 42 and is fixed to a bracket 52 that holds the axle of a saddle-ride type vehicle (not shown). The holder 51 includes a hollow portion 52a, and the inner tube 42 is screwed into the hollow portion. The bracket 52 and the cylinder 41 are connected while being aligned.

  The lower end of the cylinder 41 is provided with a through hole 41a that communicates the space between the partition member 43 and the holder 51 and the reservoir R4. As described above, the partition member 43 includes the pressure side chamber R3 and the reservoir R4. And is divided.

  In addition to the pressure side port 43a as a port, the partition member 43 is provided with an extension side port 43b, and the pressure side chamber R3 and the reservoir R4 are communicated with each other by the pressure side and extension side ports 43a and 43b.

  The pressure side port 43a is opened and closed by a leaf valve 44 stacked on the lower end of the partition member 43 in FIGS. 3 and 4, and the leaf valve 44 prevents the flow of hydraulic oil from the reservoir R4 toward the pressure side chamber R3. In addition, resistance is given to the flow of hydraulic oil from the pressure side chamber R3 toward the reservoir R4.

  On the other hand, the extension side port 43b is opened and closed by a check valve 53 stacked on the upper end of the partition member 43 in FIGS. 3 and 4, and the check valve 53 is used for the hydraulic oil flowing from the pressure side chamber R3 to the reservoir R4. While preventing the flow, the expansion side port 43b is opened with almost no resistance applied to the flow of hydraulic oil from the reservoir R4 to the pressure side chamber R3.

  A suspension spring 54 is interposed between the outer tube 48 and the inner tube 42. The suspension spring 54 biases the front fork F1 in the extending direction, and the front fork F1 is connected to the axle of the motorcycle and the vehicle body. If it is interposed between the two, the vehicle body is elastically supported.

  During the extension operation in which the inner tube 42 projects from the outer tube 48 in the front fork F1, the leaf valve 60 resists the flow of hydraulic oil from the extension side chamber R5 to the compression side chamber R3 via the passage 46a of the piston 46. To generate a predetermined pressure loss and generate a predetermined extension side damping force in the front fork F1. At the time of this extension operation, the check valve 53 is opened, and the volume of hydraulic oil that causes the piston rod 47 to retreat from the cylinder 41 is supplied from the reservoir R4 into the cylinder 41 via the extension side port 43b. Compensation is made.

  On the other hand, during the compression operation in which the inner tube 42 enters the outer tube 48 in the front fork F1, the check valve 49 is opened and moved from the compression side chamber R3 to the expansion side chamber R5 via the passage 46b provided in the piston 46. In addition, the volume of hydraulic oil that the piston rod 47 enters into the cylinder 41 becomes excessive in the cylinder 41 and is discharged from the cylinder 41 to the reservoir R4 via the pressure side port 43a. A resistance is applied by 44 to increase the pressure in the cylinder 41 to generate a predetermined compression-side damping force in the front fork F1. Thus, in the case of the front fork F1, a compression side damping force is generated by the leaf valve 43 during the compression operation.

  Hereinafter, the valve structure embodied in the pressure-side damping valve as described above will be described in detail. The leaf valve 44 has an annular shape, is stacked on the lower end of the partition member 43 in FIG. 3, and is mounted on the outer periphery of a holder 51 that is a shaft member that connects the partition member 43 to the bracket 52 and the cylinder 41. The valve 44 is urged toward the partition member 43 by a leaf spring 45 disposed below the leaf valve 44 in FIG.

  The leaf valve 44 in this embodiment is configured as a laminated leaf valve by laminating a plurality of annularly formed plates. The number of annular plates is a damping characteristic (piston) realized by this valve structure. (Depending on the damping force with respect to the speed), and may be arbitrary depending on the damping characteristics generated in the front fork F1, or may be a single one, and as shown in the figure, the damping generated in the front fork F1. Depending on the characteristics, the outer diameter of each plate can be set differently.

  The holder 51 includes a base portion 51a that is screwed to the inner periphery of the lower end of the cylinder 41, and a support portion 51b that has an outer diameter smaller than that of the base portion 51a and that supports the leaf spring 45 by connecting to the upper end in FIG. The shaft portion 51c, on which the partition member 43 is mounted on the outer periphery, rises from the axis of the support portion 51b, the base 51a, the support portion 51b, the vertical hole 51d that passes through the shaft portion 51c, and the support portion 51d that opens from the outer periphery. A horizontal hole 51e communicating with the vertical hole 51d and a flange 51f provided on the outer periphery of the lower end of the base 51a are provided. When the base portion 51a of the holder 51 is screwed to the cylinder 41, the cylinder 42 and the bracket 52 are connected by sandwiching the small diameter portion 52b provided in the hollow portion 52a of the bracket 52 between the lower end of the cylinder 41 and the flange 51f. Be able to. Moreover, the support part 51b is provided with the cylindrical sheet | seat part 51g which protrudes toward the partition member 43 side in the upper end outer periphery in FIG.

  The shaft 51 c of the holder 51 includes an annular leaf spring 45, an annular spacer 55, a leaf valve 44, a partition member 43, an annular check valve 53, a coil spring 56 that urges the check valve 53, and a spring receiver 57. Are assembled in order from the bottom in the figure.

  Specifically, the shaft portion 51c of the holder 51 is provided with a step portion 51h. The upper portion in FIG. 3 is set to have a small diameter from the step portion 51h, and the partition member 43, the check valve 53, the coil spring 56, and the spring receiver are set. 57 is attached to a portion on the small diameter side of the shaft portion 51c above the step portion 51h, and these are sandwiched by the nut 58 screwed to the step portion 51h and the tip of the shaft portion 51c to move relative to the holder 51. Fixed to impossible. On the other hand, the leaf spring 45, the spacer 55, and the leaf valve 44 are mounted below the step portion 51h of the shaft portion 51c, and are movable in the axial direction on the shaft portion 51c.

  As described above, the leaf spring 44 is annular, and is attached to the shaft 51c of the holder 51 below the step portion 51h. It is set to be in sliding contact with 51c. Further, the outer periphery of the plate spring 45 on the side opposite to the partitioning member is in contact with a sheet portion 51g provided on the support portion 51b of the holder 51, and is supported by the sheet portion 51g from the lower side in FIG. Since the inner circumference of 45 is not fixed to the shaft portion 51c and is in sliding contact, the inner circumference side can be bent downward in FIG. 3 with the inner circumference side as a free end. In this embodiment, the leaf spring 45 is formed by laminating a plurality of annular plates, and the spring constant can be adjusted by the number of laminated annular plates. Even if the spring constant is increased, the leaf spring 45 does not increase in size in the radial direction and hardly increases in size in the axial direction. Therefore, it can be applied without difficulty in the cylinder 41 having a small inner diameter. The number of annular plates can be set to an arbitrary number according to the spring constant, and may be singular. The spring constant may be set by adjusting the plate thickness.

  Further, the leaf spring 45 does not necessarily have its inner periphery slidably contacted with the outer periphery of the shaft portion 51c of the holder 51. However, as in this embodiment, the inner periphery is brought to the outer periphery of the shaft portion 51c in an unloaded state. By setting so that the leaf valve 44 is seated on the partition member 43 and the amount of bending of the leaf spring 45 is only the initial deflection, the amount of bending of the leaf spring 45 is small and the inner circumference of the leaf spring 45 is set. Since the gap between the shaft portion 51c and the shaft portion 51c is small, even if the leaf spring 45 is eccentric in the radial direction with respect to the shaft portion 51c, the amount of eccentricity is very small. Therefore, even if the leaf valve 44 is retracted from the partition member 43 and then returned to the original position and repeatedly seated on the partition member 43, the amount of eccentricity of the leaf spring 45 with respect to the shaft portion 51c becomes small. The biasing force that biases 44 is not greatly biased in the circumferential direction, and even if the lift of the leaf valve 44 from the partition member 43 is repeated, the damping characteristic does not change each time and is stable. Damping characteristics can be obtained.

  Returning, the spacer 55 interposed between the leaf spring 45 and the leaf valve 44 has an annular shape, and is in the same manner as the leaf spring 45, is a shaft portion 51c, and is in sliding contact with the lower side of the step portion 51h. The outer diameter is set smaller than the outer diameter of the leaf spring 45 and the leaf valve 44. The spacer 55 and the seat portion 51g maintain the leaf spring 45 in a constantly bent state to exert an urging force, and the leaf spring 45 is moved to the inner peripheral side of the leaf valve 44 via the spacer 55. Energizing force is applied. As described above, the spacer 55 transmits the urging force of the leaf spring 45 to the leaf valve 44 and also exerts the urging force by applying an initial deflection to the leaf spring 45, and the axial length (thickness) of the spacer 55. With this setting, the initial deflection amount of the leaf spring 45 can be adjusted. In order to facilitate this adjustment, the spacer 55 is configured by laminating a plurality of annular plates, but may be configured by a single annular plate.

  The spacer 55 can also be moved in the axial direction which is the vertical direction with respect to the shaft portion 51 c of the holder 51, similarly to the leaf spring 45 and the leaf valve 44. Therefore, the leaf valve 44 receives a force in a direction away from the partition member 43 downward in FIG. 3 by the pressure in the pressure side chamber R3 acting via the pressure side port 43a, and the force exceeds the urging force of the leaf spring 45. Then, the leaf valve 44 moves away from the partition member 43 together with the spacer 55 so that the inner peripheral side of the leaf spring 45 can be bent downward.

  When the leaf spring 45 is bent by a predetermined amount, the inner circumference of the side surface of the opposite partitioning member of the leaf spring 45 comes into contact with the inner circumference of the support portion 51b, and further bending of the leaf spring 45 is restricted, and the leaf valve The separation (retraction) of the 44 from the partition member 43 is also restricted. It should be noted that even if the inner periphery of the leaf spring 45 is bent and abuts against the support portion 51b, the support portion 51 and the leaf spring 45 are notched so that the space formed by the leaf spring 45 and the support portion 51c is not sealed. In this case, it is possible to prevent the leaf spring 45 from being bent and the leaf valve 44 from being obstructed.

  As described above, the leaf spring 45, the spacer 55, the leaf valve 44, the partition member 43, the check valve 53, the coil spring 56, the spring receiver 57, and the nut 58 are sequentially assembled to the holder 51 as a base valve portion. When assembled and the base portion 51 a of the holder 51 is screwed to the inner periphery of the lower end of the cylinder 41 in FIG. 3, the assembled base valve portion is connected to the cylinder 41 and the bracket 52.

  A needle type valve element 59 is screwed and accommodated in the vertical hole 51d of the holder 51. The needle type valve 59 can be rotated by an external operation, and in the manner of a feed screw. By changing the distance to the annular valve seat 60 provided in the middle of the vertical hole 51d, the flow path area in the bypass path bypassing the compression side and extension side ports 43a and 43b formed by the vertical hole 51d and the horizontal hole 51e is changed. Can be done.

  Since the bypass path bypasses the compression side and extension side ports 43a and 43b, the damping force on the compression side of the Freon and the fork F1 can be adjusted by adjusting the flow path area. As described above, it can be performed from the outside of the front fork F1.

  Next, the operation of the valve structure configured as described above will be described. When the moving speed (piston speed) of the piston 46 with respect to the cylinder 41 is low in the compression stroke of the front fork F1, the pressure in the pressure side chamber R1 acts on the leaf valve 44 via the pressure side port 43a and is pushed downward. Although force acts, it is pressed against the partition member 43 side by the urging force of the leaf spring 45, and this urging force cannot be overcome. The compression side port 43a is opened. In this state, when the damping coefficient of the front fork F1 is high and the piston speed is in the low speed range, the damping force quickly rises and a good riding comfort can be obtained.

  On the other hand, when the piston speed increases, the pressure in the pressure side chamber R3 that acts on the leaf valve 44 increases, and the force that pushes the leaf valve 44 downward overcomes the urging force of the leaf spring 45. When the spring 45 is bent, the leaf valve 44 is lifted from the partition member 43 to greatly open the pressure side port 43a.

  In this state, the damping coefficient of the front fork F1 is lower than when the piston speed is low. When the piston speed is in the high speed range, the damping force during the compression stroke does not become excessive, and the riding comfort in the vehicle Can be improved.

  Even in this valve structure, the leaf valve 44 that opens and closes the compression side port 43a is urged by the leaf spring 45 having a small individual difference in the spring constant. Therefore, a coil spring is used as the urging means. Compared to the conventional valve structure, the variation of the generated damping force in the front fork F1 as a shock absorber for each product can be suppressed. Furthermore, the variation can be minimized by the number of laminated annular plates constituting the leaf spring 45.

  Further, even if the number of laminated annular plates constituting the leaf spring 45 is increased or the leaf spring 45 is thickened in order to set a large spring constant in the leaf spring 45, the leaf spring 45 becomes long in the axial direction. Since there is no such thing, enlargement of the piston portion can be avoided, so that a sufficient urging force can be applied to the leaf valve 44 without sacrificing the stroke length of the front fork F1 as a shock absorber.

  Therefore, by setting the initial load by the leaf spring 45 appropriately, when the piston speed in the compression stroke is in the low speed range, the leaf valve 44 is not lifted and only the outer periphery of the leaf valve 44 is bent, and the piston is A damping force corresponding to the speed can be generated, and a compression-side damping force in a low speed region can be sufficiently generated in the front fork F1 as a shock absorber.

  Further, since the leaf valve 44 can be sufficiently urged by the leaf spring 45, when the vibration direction of the front fork F1 as a shock absorber is reversed from the compression direction to the extension direction, the leaf valve 44 is quickly pressed to the compression side. The port 43a can be returned to the closing position, and the damping force immediately after the shock absorber D is switched from the compression stroke to the expansion stroke does not become insufficient.

  Therefore, according to the valve structure described above, a stable damping force can be generated in the front fork F1 as a shock absorber, and it is sufficient even when the expansion / contraction speed of the front fork F1 as a shock absorber is in a low speed range. A damping force can be generated.

  Further, even if the spring constant of the leaf spring 45 is set to be large, it does not increase in size in the axial direction and the radial direction, so that it is suitable for a shock absorber having a small piston diameter, and is optimal for a damping valve for the shock absorber. .

  Further, the valve structure may be provided on one or both of the pressure side and the extension side of the piston 46, and the valve structure of the present invention can be embodied as a damping valve on the extension side of the base valve portion.

 This is the end of the description of the embodiment of the present invention, but the scope of the present invention is not limited to the details shown or described.

1, 41 Cylinder 2 Piston 2a as valve disc, 43a Pressure side port 2b, 43b as port Extension side port 3, 12, 19, 44, 60 Leaf valve 4, 45 Leaf spring 10 Reservoir cylinder 11, 47 Piston rod 13 Free Piston 14 Air chamber 15 Oil chamber 16 Sealing member 17 Spring 18 Partition member 18a, 18b Port 20, 49, 53 in partition member Check valve 21, 48 Outer tube 22, 42 Inner tube 23, 54 Suspension spring 24 Piston holder 24a Piston Base 24b in the holder Shaft 24c in the piston holder Vertical hole 24d in the piston holder Horizontal hole 24e in the piston holder 24f in the piston holder Step 25 in the piston holder Stopper 25a Groove 26 in the stopper, 56 Spacer 27 Valve stopper 28 Piston nut 29, 59 Needle type valve 30, 60 Annular valve seat 31 Control rod 32, 56 Coil spring 41a Through hole 43 Partition member 46a, 46b as valve disk Passage 50 Diaphragm 51 Holder 51a Base in holder 51b Support section 51c in holder Shaft section 51d in holder Vertical hole 51d in holder 51e Horizontal hole 51f in holder 51g Flange in holder 51g Sheet section 51h in holder 52 Step section in bracket 52a Hollow section in bracket 52b Small diameter section in bracket 55 Spacer 57 Spring 58 Nut D Buffer F Front fork F1 Front fork G as buffer Air chamber R Reservoir R1, R3 Pressure side chamber R2 as one chamber, etc. Reservoir as expansion side chamber R4 other chamber as the chamber

Claims (5)

A valve disc provided with a port communicating with one chamber and the other chamber formed in the shock absorber, a piston holder for connecting the valve disc to the piston rod, and a valve disc that is movably stacked in the axial direction. In a valve structure of a shock absorber provided with an annular leaf valve that opens and closes the outlet end and a leaf spring that biases the leaf valve toward the valve disk side, the piston holder rises from the base and the center of the base to A shaft portion on which the disc is mounted, and a flange that rises toward the leaf valve from the outer periphery of the top portion of the base portion. A spacer with an outer diameter smaller than that of the leaf spring is slidably mounted. Te, the valve structure of the damper, characterized in that by exerting a biasing force to maintain the deflected state the leaf spring at all times.   2. The valve structure for a shock absorber according to claim 1, wherein the initial deflection amount of the leaf spring is adjusted by setting the axial length of the spacer.   3. The shock absorber valve according to claim 2, wherein a stopper is provided to abut against the inner periphery of the side surface of the valve spring opposite to the leaf spring when the leaf spring is bent by a predetermined amount on the shaft portion. Construction.   The valve disk is a piston having a port which is slidably inserted into a cylinder in the shock absorber to form one chamber and the other chamber in the cylinder and which communicates the one chamber and the other chamber. The valve structure of the shock absorber according to any one of claims 1 to 3.   4. The shock absorber valve structure according to claim 1, wherein one of the one chamber and the other chamber is a reservoir.

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