JP2013142468A - Hydraulic shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enlarge a cross-sectional areas of a port in a damping valve so as to become advantageous in the aspect of damping force responsiveness and to be capable of avoiding a crack by back pressure action in the annular leaf valve.SOLUTION: A hydraulic shock absorber includes: a bulkhead 3 which partitions one chamber R1 and the other chamber R2; a port 3b formed in the bulkhead 3 to communicate the one chamber R1 with the other chamber R2; and an annular leaf valve 5 laminated at the one chamber side of the bulkhead 3. In the shock absorber, a valve seat 10 is provided that is formed at the one chamber side of the bulkhead 3 to open the port 3b inside and on which the annular leaf valve 5 is seated. The valve seat 10 has supporting parts 11, 12 projecting inward to support the annular leaf valve 5. The inside of the valve seat 10 having the supporting parts 11, 12 is used as the port 3b.

Description

  The present invention relates to a hydraulic shock absorber, and more particularly to an improvement of a hydraulic shock absorber incorporated in a vehicle suspension.

  In a hydraulic shock absorber incorporated in a vehicle suspension, for example, it is required to permanently generate a set damping force so that a favorable riding comfort can be maintained over a long period of time.

  For this reason, the hydraulic shock absorber includes a damping valve that generates a desired damping force. The damping valve includes, for example, a piston that is a partition wall and an annular leaf valve that is stacked on the piston.

  In the hydraulic shock absorber, the piston has a port that allows communication between the one chamber and the other chamber defined by the piston, and the annular leaf valve is fixed to the inner chamber end on the one chamber side of the piston. It is provided in a state where the outer peripheral end is free, and the downstream end of the port is closed so as to be openable.

  On the other hand, on the one chamber side of the piston, for example, as shown in Patent Document 1 and FIG. 5, a valve seat P1 for seating an annular leaf valve is provided, and this valve seat P1 is ported at the bottom (not shown). P2 is opened to allow an inflow of hydraulic oil from the port P2, and an opening window P3 for setting the size of the pressure receiving surface of the annular leaf valve is defined.

  Therefore, in the hydraulic shock absorber described above, when the other chamber upstream of the port P2 is on the high pressure side, the outer peripheral side of the annular leaf valve in which the hydraulic oil in the opening window P3 sits on the valve seat P1. The end portion is bent and flows into the one side chamber on the low pressure side through the valve seat P1, and a damping force is generated by the pressure loss at this time.

  Further, in the hydraulic shock absorber described above, the annular leaf valve functions as a check valve that closes the port P2 by being pressed in the direction of closing the port P2 in close contact with the valve seat P1 when the one chamber becomes high pressure. To do.

JP 2009-281488 A

  By the way, in a damping valve that opens and closes a port with an annular leaf valve, the damping force responsiveness of the hydraulic shock absorber is generally increased when the cross-sectional area of the port is larger and the rigidity of the oil column in the port is higher. This is advantageous in terms of improvement.

  On the other hand, when the pressure in the one chamber becomes high, the annular leaf valve is pressed against the valve seat by the pressure acting on the back surface and is pressed in the direction of closing the port. Deforms to sink into the port.

  Therefore, in order to improve the damping force responsiveness in the hydraulic shock absorber, the cross-sectional area of the port should be increased. However, the valve seat is enlarged by that amount, so the pressure applied to the rear surface of the annular leaf valve on the port side The amount of deformation becomes large when deforming to cause a problem of increased metal fatigue.

  Therefore, in the conventional hydraulic shock absorber, it has been difficult to satisfy both the improvement of the damping force responsiveness by increasing the cross-sectional area of the port and the reduction of the metal fatigue of the annular leaf valve.

  The present invention was devised in view of the above-described circumstances, and is advantageous in improving the damping force response by increasing the cross-sectional area of the port, and at the same time, metal fatigue due to pressure acting on the back surface of the annular leaf valve. It is an object of the present invention to provide a hydraulic shock absorber that can reduce the pressure.

  In order to solve the above-described object, the configuration of the present invention includes a partition body that partitions one chamber and the other chamber, a port that is formed in the partition body and communicates with the one chamber and the other chamber, In a hydraulic shock absorber having an annular leaf valve stacked on one chamber side of the partition wall, the port is formed on the one chamber side of the partition wall to open the port inward and the annular leaf valve It is assumed that a valve seat to be seated is provided, the valve seat has a support portion that protrudes inwardly to support the annular leaf valve, and the inside of the valve seat having the support portion serves as the port.

  In the hydraulic shock absorber, when the support part on the inner periphery of the valve seat supports the annular leaf valve, when the annular leaf valve becomes depressed toward the port due to the high pressure acting on the back surface It becomes possible to suppress the depression of the part facing the port of the annular leaf valve.

  Further, in the hydraulic shock absorber, the port is enlarged inside the valve seat having the support portion, so that the rigidity of the oil column in the port is increased, which is advantageous in improving the damping force response. .

  Since the support portion is formed on the inner periphery of the valve seat, it is possible to maintain a state in which the cross-sectional area of the port is increased as compared with the case where the support portion is formed at the center portion inside the valve seat or in the vicinity thereof. And it doesn't get in the way.

  As a result, according to the hydraulic shock absorber of the present invention, the cross-sectional area of the port is increased, which is advantageous in improving the damping force responsiveness, and metal fatigue due to the pressure acting on the back surface of the annular leaf valve can be reduced.

It is a fragmentary longitudinal cross-section which shows one Embodiment of the hydraulic shock absorber by this invention. It is a schematic plan view which shows the piston of the hydraulic shock absorber of FIG. It is a fragmentary longitudinal cross-section which shows the bending state of the annular leaf valve when it does not have a support part. It is a fragmentary longitudinal cross-section which shows the bending state of the annular leaf valve in the case of having a support part. It is a schematic plan view which shows the conventional piston.

  In the following, the present invention will be described based on the illustrated embodiment. The hydraulic shock absorber according to the present invention is assumed to be incorporated in, for example, a suspension of a vehicle, and has a predetermined damping action during an expansion / contraction operation. And suppress the vibration of the axle.

  In the hydraulic shock absorber, a damping valve having a piston 3 as a partition wall and an annular leaf valve 5 as a pressure side valve stacked on the one chamber side which is the upper side of the piston 3 in FIG. I have.

  Incidentally, the longitudinal section of the piston 3 in FIG. 1 is in a state indicated by the position of the XX line in FIG. 2, and FIG. 2 shows the upper end surface of the piston 3, but the ports 3a and 3b and the valve seat Only lines representing 10 etc. are drawn and the others are omitted. In the plane of the piston 3 shown in FIG. 2, the central portion is a hole (not shown) through which the tip 2a (see FIG. 1) of the rod 2 passes.

  The piston 3 is formed in an annular shape and is slidably inserted into the cylinder 1 so as to be held in the distal end portion 2a of the rod 2 that is inserted into the cylinder 1 that accommodates hydraulic oil. The one chamber R1 and the other chamber R2 And partition.

  As shown in FIG. 2, the piston 3 includes an extension-side port 3 a that is alternately formed in the circumferential direction and allows communication between the one chamber R <b> 1 and the other chamber R <b> 2 and a pressure-side port 3 b that is a port. .

  The pressure side port 3b opens at the bottom (not shown) of the recess 3c communicating with the other chamber R2 formed on the other chamber side where the lower end in FIG. 1 is the lower end side in FIG. The upper end in FIG. 1 is open inside the valve seat 10 formed on the one chamber side of the piston 3.

  1, the lower end in FIG. 1 opens at the bottom (not shown) of an opening window 3d formed at the other end of the piston 3, and the upper end in FIG. It opens to the bottom (not shown) of the recess 3e communicating with the one chamber R1.

  Therefore, in the hydraulic shock absorber, when the piston 3 moves in the cylinder 1 and the one chamber R1 and the other chamber R2 are widened and narrowed, the hydraulic oil passes through the expansion side port 3a and the pressure side port 3b. And the other chamber R2.

  On the other hand, the valve seat 10 has the annular leaf valve 5 seated on the upper surface and the pressure receiving surface of the annular leaf valve 5 is set. In this state, the downstream side end that is the upper end of the pressure side port 3b in FIG. Is open.

  The valve seat 10 is connected to the outer periphery of the inner peripheral side fixing portion 3 f formed on the one chamber side of the piston 3, and the inner peripheral side fixing portion 3 f is connected to the annular leaf valve of the valve seat 10. 5 is an inner peripheral portion (not shown) that can abut on the radially inner side.

  Incidentally, the valve seat 10 includes the inner peripheral portion, an outer peripheral portion (not shown) that can be in contact with the radially outer side of the annular leaf valve 5, and a left side portion (continuous to both ends of the inner peripheral portion and the outer peripheral portion). It has a petal shape and has a right side portion (not shown) and a right side portion (not shown).

  Further, the valve seat 10 includes a plurality of pressure-receiving surfaces of the annular leaf valve 5 that are independently set at equal intervals in the circumferential direction of the piston 3, but in the illustrated case, four pressure-side ports 3b are provided. The four are provided in a cross shape with the axial center portion (not shown) of the piston 3 as a central portion (see FIG. 2).

  The annular leaf valve 5 has an inner peripheral side end portion (not shown) having an inner peripheral side fixing portion 3f of the piston 3, and a step portion 2b between the tip portion 2a of the rod 2 and a shaft portion (not shown). The inner peripheral end is fixed and the outer peripheral end is free. The outer end (not shown) is bent to allow a gap to appear between the valve seat 10 and the hydraulic oil to pass therethrough. Allow and have a damping effect.

  Incidentally, the annular leaf valve 5 is formed by laminating a plurality of sheets having the same diameter and a plurality of sheets having different diameters as shown in the drawing. A plurality of sheets having different diameters may not be stacked, and instead of a plurality of sheets having the same diameter, a single sheet may be used.

  The annular leaf valve 4 serving as the expansion side valve is sandwiched between an inner peripheral side fixing portion 3g formed on the other end of the piston 3 and an inner peripheral side fixing portion 3g and a piston nut 6. The inner peripheral end is fixed so that the outer peripheral end is free. When the outer peripheral end that closes the downstream end of the port 3a on the expansion side so as to be openable is bent, a predetermined damping action is performed.

  By the way, in the hydraulic shock absorber of the present invention, the valve seat 10 has support portions 11 and 12 for supporting the annular leaf valve 5 on the inner periphery, and the pressure side port 3b has the support portions 11 and 12. It is assumed that it consists of the inside of the valve seat 10.

  In the hydraulic shock absorber, the cross-sectional area of the pressure-side port 3b is the cross-sectional area inside the valve seat 10, so that, for example, compared with the place disclosed in Patent Document 1 and the place shown in FIG. For this reason, the cross-sectional area of the pressure side port 3b is increased, and the rigidity of the oil column in the pressure side port 3b is increased, which is advantageous in improving the damping force response of the hydraulic shock absorber.

  Incidentally, in the present invention, the meaning that the pressure side port 3b is formed from the inside of the valve seat 10 having the support portions 11 and 12 basically means the inner peripheral edge a of the valve seat 10 (see FIG. 2). And the opening edge b (see FIG. 2) of the pressure-side port 3b are the same, that is, the cross-sectional area of the pressure-side port 3b is the same as the cross-sectional area of the valve seat 10 having the support portions 11 and 12. means.

  On the other hand, when the piston 3 is formed and molded using a mold, as shown in FIG. 2, the inner peripheral edge portion a of the valve seat 10 having the support portions 11 and 12 and the pressure side port 3b are formed. A ridge line portion c formed of an inclined surface may be formed between the opening edge portion b and the opening edge portion b.

  In this case, from the viewpoint that the ridge line portion c is provided in order to reliably form the valve seat 10, the cross-sectional area of the compression-side port 3b is a portion surrounded by the opening edge portion b. From the standpoint that the ridge line portion c is an end portion of the pressure side port 3b, it can be said that the cross-sectional area of the pressure side port 3b is a portion surrounded by the inner peripheral edge portion a of the valve seat 10.

  Therefore, in the hydraulic shock absorber according to the present invention, the cross-sectional area of the compression-side port 3b is basically the same as that of the valve seat 10 having the support portions 11 and 12, and exceptionally, the opening edge portion. It is set as the site | part enclosed by b.

  Incidentally, in the hydraulic shock absorber according to the present invention, since the opening window for opening the downstream end of the pressure side port 3b is not formed on the one chamber side of the piston 3, the formation of the piston 3 is made by the amount not forming this opening window. There is an advantage that the labor required for the operation can be saved.

  Further, in the hydraulic shock absorber, the support portions 11 and 12 are formed on the inner periphery of the valve seat 10, so that the support portions 11 and 12 are formed in the central portion inside the valve seat 10 and in the vicinity thereof. Compared to the case, there is no fear of greatly reducing the cross-sectional area of the pressure-side port 3b inside the valve seat 10, and this invention can ensure that the cross-sectional area of the pressure-side port 3b is increased.

  By the way, the support portion 11 is formed integrally with the inner periphery of the valve seat 10, that is, the inner periphery of the central portion (not shown) in the circumferential direction of the outer peripheral portion, and the upper surface facing the annular leaf valve 5 is formed on the valve seat. 10 is the same surface as the upper surface of the valve 10, and the shape of the upper surface in plan view is a divergent shape toward the outer periphery of the valve seat 10.

  And the seating property of the annular leaf valve 5 when the annular leaf valve 5 is seated on the valve seat 10 is inhibited by making the upper surface of the support portion 11 facing the annular leaf valve 5 flush with the upper surface of the valve seat 10. It becomes possible not to.

  Further, since the support portion 11 has a shape in plan view that extends toward the outer peripheral portion of the valve seat 10, hydraulic oil from the pressure-side port 3 b is allowed to flow between the outer peripheral end of the annular leaf valve 5 and the valve seat. When passing through the gap appearing between the first and second chambers 10 and flowing out into the one chamber R1, the so-called right and left are separated from the support portion 11 as a boundary.

  That is, in the state where the support portion 11 is not provided, as shown in FIG. 3, the hydraulic oil from the pressure-side port 3b is separated from the central portion X of the outer peripheral portion of the valve seat 10 and the annular leaf valve opposed thereto. Therefore, the hydraulic oil tends to pass through the corner portions on both sides of the valve seat 10 preferentially.

  From the above, the support portion 11 is provided at the central portion of the outer peripheral portion of the valve seat 10, so that the hydraulic oil from the pressure side port 3 b is transferred to the valve seat 10 as indicated by arrows A and B in FIG. 4. A situation where hydraulic fluid passes between the corner portions on both sides of the valve seat 10 and the outer peripheral side end portion of the annular leaf valve 5 opposed thereto is assumed to be diverted toward the corner portions on both sides. It is supposed to be embodied.

  That is, the support portion 11 is provided at the central portion of the outer peripheral portion of the valve seat 10, so that the hydraulic oil is between the central portion of the outer peripheral portion of the valve seat 10 and the outer peripheral side end portion of the annular leaf valve 5 facing this. Without concentrating on the valve, the passage between the entire outer peripheral portion of the valve seat 10 and the outer peripheral side end portion of the annular leaf valve 5 facing the valve seat 10 is wide.

  As a result, in the annular leaf valve 5, compared to the case where the so-called narrowed specific portion of the outer peripheral side end portion is largely bent, the so-called widened portion is bent as a whole. And the valve seat 10 are made uniform, and the flow rate of the hydraulic oil passing through the gap does not vary, and the generation of abnormal noise (swoosh noise) is suppressed.

  In contrast to the support portion 11 provided as described above, the inner support portion 12 is, as shown in the figure, located at the inner peripheral portion of the valve seat 10, that is, the central portion in the circumferential direction of the inner peripheral portion (not shown). ).

  By providing the inner support portion 12, metal fatigue in the annular leaf valve 5 is more effectively prevented. For the inner support portion 12, for example, between the outer support portion 11 and the valve seat 10. When the distance to the inner peripheral portion is short or when the pressure acting on the back surface of the annular leaf valve 5 is low, the circumferential length of the inner peripheral portion is extremely shorter than the circumferential length of the outer peripheral portion. Of course, the formation may be omitted in some cases.

  The inner support portion 12 does not perform the function of dividing the hydraulic oil as compared with the outer support portion 11 described above, and therefore the planar shape thereof is the same as or similar to the outer support portion 11. It is not necessary to be formed, and is arbitrary.

  However, in view of the fact that the piston 3 is formed by molding, from the viewpoint of improving the so-called die-cutting property, the planar shape of the support portion 12 is rounded so as not to cause an angled portion to appear as a whole. It is preferable that it is made into the shape.

  In view of the above, the support portions 11 and 12 are not shown but instead of the illustrated portions, the left and right sides that form the valve seat 10, that is, the left side and the right side that are continuous to both ends of the outer and inner peripheral parts. It is good also as integrally forming in the inner periphery of this, especially the inner periphery of the center part of radial direction.

  Further, as shown in FIG. 1, the support portions 11 and 12 are formed between the one chamber side and the other end of the piston 3 as shown by the broken line in FIG. In view of the function of the portions 11 and 12, the formation of the other end side of the piston 3 may be omitted, and it may be partially formed from the one chamber side to the lower vicinity thereof.

  In the hydraulic shock absorber according to the present invention formed as described above, during the contraction operation in which the piston 3 descends in the cylinder 1 at a high speed, the hydraulic oil from the other chamber R2 which is on the high pressure side is supplied to the annular leaf valve 5. The outer peripheral side end portion is bent, passes through a gap that appears between the valve seat 10 and flows out into the one chamber R1, and the valve characteristic is attenuated by the pressure loss at this time.

  At the time of this contraction operation, the oil column rigidity in the pressure side port 3b is increased, so that it is possible to improve the damping force responsiveness in the annular leaf valve 5 that closes the pressure side port 3b so as to be openable.

  In this contraction operation, the cross-sectional area of the pressure side port 3b increases, so that the hydraulic oil does not flow out into the one chamber R1 on the low pressure side at a high speed. Generation of abnormal noise (swoosh sound) due to outflow to the low pressure side can be suppressed.

  Contrary to the above, during the extension operation in which the piston 3 moves up in the cylinder 1 at a high speed, the hydraulic oil from the one chamber R1 on the high pressure side deflects the outer peripheral side end of the annular leaf valve 4 and flows into the other chamber R2. Therefore, the valve characteristic is attenuated by the pressure loss at this time.

  During this extension operation, the high pressure from the one chamber R1 acts on the back surface of the annular leaf valve 5 that functions as a check valve. The valve seat 10 on which the annular leaf valve 5 is seated supports the annular leaf valve 5. Since the portions 11 and 12 are provided on the inner periphery, the deformation of the annular leaf valve 5 is prevented even when the annular leaf valve 5 is depressed inside the valve seat 10 due to the back pressure action. Metal fatigue is reduced.

  On the other hand, during the contraction operation of the hydraulic shock absorber in which the piston 3 descends in the cylinder 1 at a very low speed, although not shown, for example, when the annular leaf valve 5 has an orifice made of a notch, or the annular leaf valve 4 is seated. When the valve seat 10 has an orifice made of stamping, and further, when the support portion 11 has a choke made of a groove, the hydraulic oil from the other chamber R2 passes through this orifice or choke and flows out into the one chamber R1. However, the damping action of the orifice characteristic or the choke characteristic is performed, and the hydraulic shock absorber does not rapidly contract. In addition, when forming the choke which consists of a groove | channel in the support part 11, it becomes advantageous at the point which can lengthen a passage length.

  When the hydraulic shock absorber extends at an extremely low speed, although not shown, for example, when the annular leaf valve 4 has an orifice made of a notch, or the valve seat on which the annular leaf valve 4 is seated is an orifice made by stamping. In this case, the hydraulic oil from one chamber R1 passes through this orifice and flows into the other chamber R2, so that the orifice characteristic is damped, and the hydraulic shock absorber does not extend rapidly.

  As described above, the hydraulic shock absorber according to the present invention is a single cylinder upright type, the cylinder 1 is a lower end side member and is connected to the axle side of the vehicle, and the rod 2 is an upper end side member. Although it is connected to the vehicle body side, instead of this, although not shown, the hydraulic shock absorber may be set in an inverted type, and instead of being formed in a single cylinder type, a double cylinder type is used. It may be formed.

  In the above description, the partition body is described as the piston 3 in the cylinder 1. However, instead of this, the partition body may be a valve disk constituting the base valve in the cylinder 1 although not illustrated. good.

  Further, in the above description, the pressure side port 3b has a larger sectional area and the valve seat 10 on which the pressure side leaf valve 5 is seated is provided with the support portions 11 and 12, but instead of this, In conjunction with this, the expansion side port 3a may have a larger cross-sectional area, and the valve seat on which the expansion side leaf valve 4 is seated may be provided with a support portion.

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Rod 2a Tip part 2b Step part 2c Tip screw part 3 Piston which is a partition body 3a Port on extension side 3b Port on pressure side which is port 3c, 3e Recessed part 3d Opening window 3f, 3g Inner peripheral side fixed part Valve 6 Piston nut 10 Valve seat 11, 12 Supporting part a Inner peripheral edge part b Opening edge part c Edge line part R1 One chamber R2 Other chamber X, Y part

Claims (3)

A partition body that partitions the one chamber and the other chamber, a port that is formed in the partition body and communicates with the one chamber and the other chamber, and an annular leaf valve that is stacked on the one chamber side of the partition body In the hydraulic shock absorber that has
A valve seat that is formed on the one chamber side of the partition wall and opens the port inward and seats the annular leaf valve;
The valve seat has a support portion that protrudes inward on the inner periphery to support the annular leaf valve,
A hydraulic shock absorber characterized in that the inside of the valve seat having the support portion is used as the port.   The valve seat is continuous with an inner peripheral portion capable of contacting the radially inner side of the annular leaf valve, an outer peripheral portion capable of contacting the radially outer side of the annular leaf valve, and both ends of the inner peripheral portion and the outer peripheral portion. The left side portion and the right side portion, and the support portion is provided on both the inner peripheral portion and the outer peripheral portion, the outer peripheral portion, or the left side portion and the right side portion. Hydraulic shock absorber.   The said support part is provided in the center part of the circumferential direction of the said outer peripheral part of the said valve seat, The planar shape of the upper surface which becomes the same surface as the upper surface of the said valve seat becomes a divergent shape toward the outer periphery. The hydraulic shock absorber according to claim 2.

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