JP4695490B2 - Shock absorber valve structure and shock absorber - Google Patents

Description

  The present invention relates to an improved shock absorber valve structure and 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 the shock absorber to which this valve structure is applied, as shown in the figure, when the piston speed when the piston P moves upward is in the low speed region, the outer peripheral side of the leaf valve L is stacked on the leaf valve L. Since it bends with the contact part as a fulcrum, as shown in FIG. 5, it exhibits substantially the same damping characteristics as the valve structure in which the inner periphery is fixedly supported. The pressure of the hydraulic oil passing through the valve acts on the leaf valve L, and the leaf valve L lifts and retreats in the axial direction from the piston P together with the main valve M against the urging force of the spring S. Compared with the valve structure of the shock absorber supported by the vehicle, the flow passage area is increased and the damping force is suppressed from being excessive, so that the riding comfort in the vehicle can be improved.
Japanese Patent Laying-Open No. 2004-190716 (FIG. 1)

  However, the proposed valve structure as described above and the shock absorber to which the valve structure is applied are useful techniques in that the ride comfort in the vehicle can be improved. is there.

  For example, when the piston speed, that is, the expansion / contraction speed of the shock absorber reaches a 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 expansion / contraction speed. The attenuation 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-described problems, and the object of the present invention is to improve the riding comfort in the vehicle even when the expansion / contraction speed of the shock absorber reaches a high speed region. It is to provide a shock absorber valve structure and shock absorber.

In order to solve the above-described object, the problem-solving means of the present invention includes a valve disk in which a port is formed, a shaft member rising from a shaft center portion of the valve disk, and an outer periphery of the shaft member inserted into the outer periphery. An annular leaf valve that is slidably contacted and stacked on the valve disk to close the port, and an annular valve that is inserted into the outer periphery of the shaft member and slidably contacts the outer periphery, and is stacked on the leaf valve and restricts the amount of bending of the leaf valve. In a valve structure of a shock absorber provided with a holding member and an urging means for urging the leaf valve via the valve holding member in the direction of closing the port, a cylinder portion is provided on the outer periphery of the valve disk, An annular flow path that provides resistance to the flow of fluid passing through the port is formed between the inner periphery and the outer periphery of the valve holding member. Characterized in that a bypass passage which is closed by only.

Another problem-solving means of the present invention is a cylinder, a piston that is slidably inserted into the cylinder and that separates the two pressure chambers, and is movably inserted into the cylinder via the piston. A piston rod, a port communicating with the two pressure chambers provided in the piston, a piston nut screwed to the tip of the piston rod protruding from the axial center of the piston and fixing the piston to the piston rod, and the piston An annular leaf valve that is inserted into the outer periphery of the nut and slidably contacts the outer periphery and is stacked on the piston to close the port, and an annular leaf valve that is inserted into the outer periphery of the piston nut and slidably contacts the outer periphery and is stacked on the leaf valve. An annular valve restraining member that regulates the amount of bending of the leaf and a leaf bar In the shock absorber provided with the biasing means for biasing the valve, a cylinder is provided on the outer periphery of the piston, and the flow of the fluid passing through the port is resisted by the inner periphery of the cylinder and the outer periphery of the valve holding member. An annular flow path is formed, and a bypass flow path that is closed by bending of the leaf valve is provided in the valve holding member .

  According to the valve structure and the shock absorber of the shock absorber of the present invention, when the expansion / contraction speed of the shock absorber reaches the high speed region, the bypass flow path is blocked by the bending of the leaf valve, and the expansion / contraction speed is in the medium speed region. The damping coefficient can be increased, and even when the expansion / contraction speed of the shock absorber reaches the high speed range, the damping force is not insufficient, vibration is sufficiently suppressed, and the ride comfort in the vehicle is improved. Can do.

  Furthermore, in a situation where the amplitude at which the shock absorber is extended to the maximum and the expansion / contraction speed reaches a high speed region, the damping coefficient can be increased to increase the damping force generated by the shock absorber. Therefore, the expansion / contraction speed of the shock absorber can be quickly reduced, and the impact at the time of 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 showing a state in which the leaf valve is in contact with the valve holding member. FIG. 3 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.

  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 that is a shaft member that rises from the shaft center portion of 1, an annular leaf valve 10 that is stacked on the piston 1 and closes the port 2 when the piston nut 4 is inserted on the inner peripheral side, and a leaf valve 10 An annular valve restraining member 11 that is stacked and restricts the amount of deflection of the leaf valve 10, a coil spring 15 that is an urging means that biases the leaf valve 10 through the valve restraining member 11 in the direction of closing the port 2, and a piston An annular flow path 16 that provides resistance to the flow of fluid passing through the port 2 by the cylindrical portion 1f provided on the outer periphery of the valve 1 and the outer periphery of the valve holding member 11 , It is constituted by a bypass passage 17 provided in the valve restraining member 11, the bypass passage 17 is adapted to be closed by deflection of the leaf valve 10.

  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 passing through a head member (not shown), the piston 1 provided at the end of the piston rod 5, and two pressures separated by the piston 1 in the cylinder 40 The upper chamber 41 and the lower chamber 42, which are chambers, a sealing member (not shown) for sealing the lower end of the cylinder 40, and a cylinder internal volume change corresponding to the volume of the piston rod 5 protruding and retracting from the cylinder 40 are not shown. A cylinder or an air chamber is provided, and the cylinder 40 is filled with a fluid, specifically, hydraulic oil.

  In the above 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 port 2 passes from the upper chamber 41 to the lower chamber 42. When the hydraulic oil moves, 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 disk is formed in a bottomed cylindrical shape, and an insertion hole 1b through which a piston rod 5 of a shock absorber is inserted into an axial center portion of the bottom portion 1a, A window 3 communicating with the port 2, a valve seat 1c formed on the outer peripheral side of the window 3 serving as an outlet end of the port 2, and a cylindrical portion 1f extending on the outer peripheral side 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 tip of the piston rod 5 is set smaller than the upper outer diameter (not shown), similar to the piston rod R of the conventional shock absorber shown in FIG. 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, the piston nut 4 that forms a part of the shaft member includes a cylindrical portion 4a and a flange 4b extending from the outer periphery of the lower end in FIG. 1, and the outer periphery of the lower end of the cylindrical portion 4a has a small diameter. A small diameter portion 4c is formed.

  Then, 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 and the like (not shown), and the piston nut from the lower side in FIG. 4 is screwed into a screw portion 5 a provided at the tip of the piston rod 5, whereby the piston 1 is sandwiched between the step portion of the piston rod 5 and the upper end of the piston nut 4 and fixed to the piston rod 5.

  In addition, the lower end opening part in the insertion hole 1b provided in the bottom part 1a of the piston 1 is expanded in diameter, and the enlarged diameter part 1e is provided, and a step part is formed, and FIG. 1 of the small diameter part 4c in the cylinder part 4a is formed in this step part. The middle and upper ends can be inserted.

  Moreover, as mentioned above, by making the piston 1 into the shape of a bottomed cylinder, 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. be able to.

  A plurality of annular spacers 7 having a smaller diameter than the leaf valve 10 slidably contacting the outer periphery of the small diameter portion 4c of the cylindrical portion 4a of the piston nut 4 are stacked on the bottom portion 1a of the piston 1, and below the spacer 7 The leaf valve 10 slidably contacting the outer periphery of the small diameter portion 4c is stacked, and a plurality of annular spacers 8 having a smaller diameter than the leaf valve 10 and slidably contacting the outer periphery of the small diameter portion 4c are stacked from below the leaf valve 10. In addition, a valve restraining member 11 that is slidably contacted with the outer periphery of the small diameter portion 4c from below the spacer 8 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, the valve pressing member 11 stacked at the lowest position in FIG. 1 includes a cylindrical portion 11b and a flange 11a extending from the upper outer periphery of the cylindrical portion 11b. The flange 11a and the piston nut A coil spring 15 as an urging means is interposed between the four flanges 4b, and the coil spring 15 presses the leaf valve 10 toward the valve seat 1c.

  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, the leaf valve 10 and the valve restraining member 11 resist the urging force 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 increases. Thus, the coil spring 15 is compressed so that the entire leaf valve 10 moves backward in the axial direction from the piston 1, that is, lifts downward in FIG.

  The outer periphery of the valve restraining member 11 is opposed to the cylindrical portion 1f of the piston 1. The outer periphery of the valve restraining member 11 and the inner periphery of the cylindrical portion 1f are resistant to the flow of fluid passing through the port 2. An annular channel 16 is provided to provide

  Further, the valve holding member 11 is provided with a bypass channel 17 penetrating vertically in FIG. 1. The bypass channel 17 is bent against the upper surface of the valve holding member 11 because the outer periphery of the leaf valve 10 is bent. As shown in FIG. 2, when the expansion / contraction speed of the shock absorber is equal to or higher than a predetermined speed, the leaf valve 10 moves backward from the piston 1 and the outer periphery of the leaf valve 10. Is bent and comes into contact with the upper surface of the valve holding member 11 so as to be closed.

  And the predetermined speed at the time of expansion and contraction of the shock absorber when the outer periphery of the leaf valve 10 is bent and closes the bypass flow path 17 can be adjusted by the bending rigidity of the leaf valve 10, and in this embodiment, 1 m / S or more. In consideration of practicality, the predetermined speed may be set to 1 m / s or more and 2 m / s or less. Note that the number of the bypass flow paths 17 described above is arbitrary, and not only one but also a plurality may be provided.

  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, the piston 1 moves upward and receives the pressure of the hydraulic oil passing through the port 2, and the outer periphery of the leaf valve 10 bends. Increases, the outer peripheral side of the leaf valve 10 abuts against the valve restraining member 11, and further bending of the leaf valve 10 is restricted. It can be adjusted by setting the axial thickness of the entire interposed spacer 8. In addition, if the convex part which performs the function similar to the spacer 8 is provided in the inner peripheral side upper part in FIG. 1 of the valve | bulb holding member 11, the spacer 8 can also be abbreviate | omitted.

  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 and the shock absorber in the embodiment 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 increases, The hydraulic oil in the upper chamber 41 tries to move into the lower chamber 42 through the port 2.

  When the piston speed, which is the expansion / contraction speed of the shock absorber, is in the low speed region, the leaf valve 10 cannot be lifted back from the piston 1 against the urging force of the coil spring 15, and the leaf valve 10 is Since the spring 15 is urged by the spring 15 so as to close the port 2, the outer peripheral edge of the leaf valve 10 bends with the outer peripheral edge of the spacer 8 as a fulcrum, and the hydraulic oil flows through the port 2 to the leaf valve. 10 passes through a gap between the leaf valve 10 and the valve seat 1c formed by separating from the valve seat 1c. In this case, the hydraulic oil that has passed through the gap between the leaf valve 10 and the valve seat 1c has a low piston speed, so the outer periphery of the leaf valve 10 does not contact the upper surface of the valve restraining member 11 in FIG. Since the bypass channel 17 is not closed, the bypass channel 17 passes through the bypass channel 17 and the annular channel 16 and moves from the upper chamber 41 to the lower chamber 42.

  The damping characteristics (relationship of the damping force with respect to the piston speed) at this time are as shown in FIG. 3, 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 middle speed region, the difference between the pressure in the upper chamber 41 and the pressure in the lower chamber 42 increases, and the force for pushing the hydraulic oil leaf valve 10 downward in FIG. At the same time, the force overcomes the urging force of the coil spring 15, and the entire leaf valve 10 is retracted in the axial direction from the piston 1, 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. The gap becomes larger. When the piston speed is in the middle speed range, the piston speed, which is the speed at the time of expansion / contraction of the shock absorber, does not reach the predetermined speed, and the outer periphery of the leaf valve 10 abuts on the upper surface of the valve holding member 11. Since the bypass passage 17 is maintained in an open state, the bypass passage 17 moves from the upper chamber 41 to the lower chamber 42 through the bypass passage 17 and the annular passage 16 even when the piston speed is in the medium speed region.

  Therefore, the damping characteristic when the piston speed is in the medium speed region is as shown in FIG. 2, which is proportional to the increase in the piston speed, but the damping coefficient is smaller than the low speed region, and the slope of the damping characteristic is small. Become.

  When the piston speed reaches a high speed region that is equal to or higher than the predetermined speed, the force of pushing down the leaf valve 10 of the hydraulic oil further increases, and the leaf against the urging force of the coil spring 15 as shown in FIG. The valve 10 and the valve holding member 11 are retracted from the piston 1, and the leaf valve 10 is also greatly bent and its outer periphery comes into contact with the upper surface of the valve holding member 11 in FIG.

  Then, the bypass flow path 17 provided in the valve holding member 11 is closed by the leaf valve 10.

  Accordingly, when the piston speed reaches the high speed region, the flow passage area of the passage cross-section integral of the bypass passage 17 is reduced, and the hydraulic oil that has passed through the port 2 passes only through the annular flow passage 16 and enters the lower chamber 42. The rate of increase in damping force (damping coefficient) with respect to piston speed when the piston speed is in the high speed region is greater than the rate of increase (damping coefficient) with respect to piston speed when the piston speed is in the medium speed region. growing.

  That is, since the damping coefficient when the piston speed is in the high speed region is larger than the damping coefficient when the piston speed is in the medium speed region, the damping characteristics when the piston speed is in the high speed region are shown in FIG. Thus, the damping coefficient is larger than the medium speed range, which is proportional to the increase in piston speed, and the slope of the damping characteristic becomes larger.

  Therefore, in the valve structure of the shock absorber in the present embodiment, when the piston speed reaches the high speed region, the bypass flow path is closed by the deflection of the leaf valve, and the piston speed is in the middle speed region. The damping coefficient can be increased, and even when the piston speed reaches the high speed region, the damping force is not insufficient, vibration is sufficiently suppressed, and 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 this embodiment, the predetermined speed at the time of expansion / contraction of the shock absorber in which the bypass channel 17 is closed by the leaf valve 10 is set to be 1 m / s or more, that is, the damping coefficient is large. Since the boundary between the medium speed region and the high speed region of the piston speed is set to be 1 m / s or more, the damping coefficient can be kept relatively small when the piston speed is in the medium speed region. Therefore, the damping force does not become excessively large, and the riding comfort in the vehicle can be ensured.

  In addition, by setting the boundary between the medium speed region and the high speed region of the piston speed at which the damping coefficient is large to be 1 m / s or more and 2 m / s or less, it is suitable for an actual vehicle to which a shock absorber is applied. Will be improved.

  In the above-described embodiment, 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 lower end of the coil spring 15 in FIG. 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, and the piston 1 is provided with an insertion hole 1a. The piston rod 5 is projected so as to be inserted into the tip end portion of the piston 5. However, a shaft member that is integral with or separate from the piston 1 that is a valve disk may be provided in the shaft center portion of the piston 1.

  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 state which the leaf valve contact | abutted to the valve | bulb holding member. 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 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 valve disc 1b Bottom part 1b Insertion hole 1c Valve seat 1d, 2 Port 1e Expanded-diameter part 1f, 4a, 11b Cylindrical part 3 Window 4 Piston nut 4b, 11a which is a shaft member 4c Small diameter part 5 Piston rod 5a Screw part 7 , 8 Spacer 10 Leaf valve 11 Valve restraining member 15 Coil spring 16 as urging means Annular flow path 17 Bypass path 40 Cylinder 41 Upper chamber 42 Lower chamber

Claims (5)

A valve disk in which a port is formed, a shaft member rising from the axial center of the valve disk, and an annular leaf valve that is inserted into the outer periphery of the shaft member and is in sliding contact with the outer periphery and is stacked on the valve disk and closes the port And an annular valve restraining member that is inserted into the outer periphery of the shaft member, is in sliding contact with the outer periphery, is laminated on the leaf valve, and regulates the amount of bending of the leaf valve, and the leaf through the valve restraining member in the direction of closing the port. In a valve structure of a shock absorber provided with an urging means for urging the valve, a cylinder portion is provided on the outer periphery of the valve disk, and the fluid passing through the port is formed by the inner periphery of the cylinder portion and the outer periphery of the valve holding member. An annular flow path that provides resistance to the flow is formed, and a bypass flow path that is blocked by the bending of a leaf valve is provided in the valve holding member. Valve structure that buffer. 2. The shock absorber valve structure according to claim 1, wherein the bypass flow path is closed by the bending of the leaf valve when the expansion and contraction speed of the shock absorber is equal to or higher than a predetermined speed. 3. 3. The shock absorber valve structure according to claim 2, wherein when the expansion / contraction speed of the shock absorber is 1 m / s or more, the bypass flow path is closed by bending of the leaf valve. A cylinder, a piston slidably inserted into the cylinder and separating two pressure chambers in the cylinder, a piston rod movably inserted into the cylinder via the piston, and the 2 provided in the piston A port communicating with the two pressure chambers, a piston nut screwed to the tip of the piston rod protruding from the axial center of the piston and fixing the piston to the piston rod, and inserted into the outer periphery of the piston nut to be in sliding contact with the outer periphery And an annular leaf valve that is stacked on the piston and closes the port, and an annular valve holding member that is inserted into the outer periphery of the piston nut and is in sliding contact with the outer periphery and that is stacked on the leaf valve and regulates the amount of bending of the leaf valve. And a biasing means for biasing the leaf valve through the valve restraining member in the direction of closing the port. In the vessel, a cylindrical portion is provided on the outer periphery of the piston, and an annular flow path is provided between the inner periphery of the cylindrical portion and the outer periphery of the valve holding member to provide resistance to the flow of fluid passing through the port. A shock absorber provided with a bypass flow path that is closed by bending of a leaf valve. 5. The bypass flow path according to claim 4, wherein the bypass passage is opened when the leaf valve is retracted from the piston against the urging force of the urging means, and is closed when the valve holding member is retracted by a predetermined amount or more from the valve disk. The shock absorber described.

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