JPH09217778A - Valve structure of hydraulic shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve structure of a hydraulic shock absorber, by which a leaf valve for very low-speed is prevented from biting in assembling. SOLUTION: A damping force producing mechanism is composed of an orifice provided leaf valve 8 whose inner peripheral side is pinched by an inner seat surface 106D of a piston and a piston nut 114 and whose outer peripheral side is brought in contact with an outer seat surface 106E of the piston, and a very low-speed leaf valve 111 incorporated in a spring seat assembly S 112 to be slidably guided by a cylindrical part 114A of the piston nut 114 and for energizing the leaf valve 8 from the back surface by a spring 113 in a state where the inner peripheral side is pinched between a spacer 109 to be taken as a supporting point of deflection and a disc 110 on which an opening window 110A communicated with an orifice 8B of the leaf valve 8 is formed and it faces the lower surface of the opening window 110A. Operating oil from an upper chamber A is parallely released to a lower chamber B through the leaf valve 8 and the leaf valve 111.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a valve structure for generating a damping force of a hydraulic shock absorber that suppresses vibration of a vehicle body such as a suspension system of an automobile.

[0002]

2. Description of the Related Art As this type of hydraulic shock absorber, for example, one disclosed in Japanese Utility Model Laid-Open No. 4-74753 shown in FIG. 3 (FIG. 3 corresponds to FIG. 7 of the official gazette) has been developed.
First, an outline of the structure will be described with reference to FIG. The hydraulic shock absorber mounted between the vehicle body and the wheels via the connecting member is
A piston valve PV is attached to the piston rod 2, and the cylinder 1 having the lower end portion to which the base valve BV is attached is housed in the outer cylinder 18 so that the piston valve PV is slidably housed therein. The packing case 17 accommodated is inserted from the upper part of the outer cylinder 18 and then the upper end of the outer cylinder 18 is hermetically sealed by welding all around. A tank chamber C is formed between the cylinder 1 and the outer cylinder 18.

When the piston rod 2 rises in the cylinder 1 filled with hydraulic oil, the sealed hydraulic oil in the piston upper chamber A flows out to the piston lower chamber B via the piston valve PV, The passage resistance at this time becomes the extension side damping force. The hydraulic oil corresponding to the piston rod withdrawal volume due to the rise of the piston rod 2 is transferred to the base valve arranged at the lower end of the cylinder 1 via the BV to the tank chamber C.
More inhaled.

Next, the piston portion of this hydraulic shock absorber will be described. A lower part of the piston rod 2 is provided with a spigot part 2A having a diameter smaller than that of the upper part, and a valve retainer 3, a leaf spring 4, a spacer 14, a check valve 5, a piston 11, a leaf valve with an orifice 8, a spacer 2 are provided therein.
2, the guide 9, and the leaf valve 7 for very low speed, the inner diameter of which is guided by a plurality of protrusions 9B provided on the outer periphery of the guide 9, are sequentially inserted. Finally, the piston valve 13 is formed by screwing the piston nut 13 with the spring seat 10 urged by the spring 12 and fastening it with a prescribed torque.

A piston 11 which divides the inside of the cylinder 1 into a piston upper chamber A and a piston lower chamber B has an outer peripheral passage 1
1A and the inner peripheral side passage 11B are formed. An annular opening window 11C is formed at the lower end of the inner peripheral passage 11B, and the opening leaf 11C is provided with an orifice leaf valve 8 as shown in FIG. The spacer 22 provided with the opening window 22A as shown in FIG. 3 (C) faces the spacer 22 via the guide 9 while being fixed on the inner peripheral side by the piston nut 13. In the so-called very low to low speed range where the piston speed is small and the pressure difference between the opening window 11C at the lower part of the piston and the lower piston chamber B is small, the outer periphery of the leaf valve 8 with an orifice biased by the spring 12 is closed. .

Since the opening window 11C at the bottom of the piston communicates with the opening 22A of the spacer 22 through the orifice 8B of the leaf valve 8 with an orifice, the spacer 2
The inner peripheral side of the very low speed leaf valve 7 facing the second opening window 22A is pushed open by using the outer peripheral flange portion of the spring seat 10 as a supporting point, and passes through the outer peripheral passage 9A of the guide 9 shown in FIG. 3 (D). , The inner recess 10C of the spring seat 10
And, it is opened to the piston lower chamber B through the outer peripheral notch 10A, and a damping force in a very low speed to low speed region is generated by the passage resistance at this time.

Since the flow rate of the hydraulic oil passing through the orifice 8B is small in the very low speed range, a pressure difference before and after the orifice 8B hardly occurs. However, when the very low speed leaf valve 7 downstream of the orifice is pushed open. A linear damping force can be obtained because passage resistance corresponding to the flexural rigidity is generated even with a small flow rate.

As the piston speed increases, the flow rate passing through the orifice 8B also increases, and the pressure difference before and after the orifice 8B also increases. As the piston speed approaches the medium speed range,
Since the pressure difference between the opening window 11C at the lower part of the piston and the lower part chamber B of the piston becomes large, the outer periphery of the leaf valve 8 with an orifice urged by the spring 12 is pushed open from the seat surface of the lower surface of the piston, so that the hydraulic oil is transferred to the piston Lower chamber B
And the damping force in the middle speed range and thereafter is generated by the passage resistance at this time.

That is, the upstream leaf valve 8 with an orifice and the downstream low-speed leaf valve 7 are structurally stacked in series, but the piston speed increases and the orifice 8B provided in the leaf valve with an orifice increases. When the pressure difference between the front and rear exceeds a set pressure determined by the urging force of the spring 12 and the flexural rigidity of the leaf valve 8 with an orifice,
Since the leaf valve with an orifice 8 itself is pushed open from the seat surface of the lower surface of the piston and operates as a damping force generating valve, the pressure difference before and after the orifice 8B does not increase further, and even if the piston speed further increases, The flow rate of the low-speed leaf valve 7 is constant.

The above description is for the cylinder 1 filled with hydraulic oil.
Regarding the extension side in which the piston rod 2 rises, on the contrary, when the piston rod 2 descends, the working oil corresponding to the piston rod entering volume of the sealed piston lower chamber B is A base valve mounted on the lower end of the cylinder 1 except that the check valve 5 urged by the leaf spring 4 is pushed open and passed through the outer peripheral passage 11A to replenish the piston upper chamber A which becomes negative pressure. It flows out into the tank chamber C via BV, and the passage resistance at this time becomes the compression side damping force.

[0011]

SUMMARY OF THE INVENTION In the actual open flat 4-74753 described in the prior art, the inner diameter of the very low speed leaf valve 7 is a plurality of projections 9 provided on the outer circumference of the guide 9.
It operates by being guided by B. However, when assembling the hydraulic shock absorber, the fine low speed leaf valve 7 is misaligned and the guide 9 and the spacer 22 or the guide 9 and the piston nut 1 are operated.
The inner peripheral side may be caught between 3 and and may be bitten. In this case, the very low speed leaf valve 7 that functions by being pushed open on the inner peripheral side becomes inoperable and loses its function as a damping valve.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a valve structure of a hydraulic shock absorber in which a very low speed leaf valve is not caught during assembly. That is.

[0013]

In order to solve the above-mentioned problems, the first means of the present invention is to use a piston that is assembled to the lower end of a piston rod and is movably inserted into the cylinder. In the hydraulic shock absorber having a damping force generation mechanism that divides the interior into two oil chambers and controls the flow of hydraulic oil generated in a communication passage that communicates the two oil chambers to generate a damping force, The generating mechanism includes a leaf valve with an orifice in which the inner seat side of the piston and the inner peripheral side are held by a piston nut, and the outer peripheral side abuts the outer seat surface of the piston, and a downstream side of the orifice provided in the leaf valve with the orifice. And is slidably guided by the cylindrical portion of the piston nut, and biases the leaf valve with the orifice from the back side by a spring. In the pulling seat subassembly, the inner peripheral side is clamped by a canzer serving as a bending support point and a disk having an opening window communicating with the orifice of the leaf valve with an orifice, and the inner surface is opposed to the lower surface of the opening window. It consists of a built-in low speed low speed leaf valve, and by releasing the hydraulic oil from the piston upper chamber via the communication passage in parallel to the piston lower chamber via the leaf valve with orifice and the low speed low speed leaf valve. is there.

The second means divides the inside of the cylinder into two oil chambers by a piston that is assembled to the lower end of the piston rod and is movably inserted into the cylinder.
In a hydraulic shock absorber having a damping force generation mechanism that controls a flow of hydraulic oil generated in a communication passage that communicates two oil chambers to generate a damping force, the damping force generation mechanism and an inner seat surface of the piston. A leaf valve with an orifice in which the inner peripheral side is held by the piston nut and the outer peripheral side abuts the outer seat surface of the piston, and a slide valve on the cylindrical portion of the piston nut located downstream of the orifice provided in the leaf valve with the orifice. On the upper surface of the canzer, which is superposed on the upper side of the valve stopper for restricting the deflection and serves as a supporting point of the deflection, on the disk subassembly that is movably guided and biases the leaf valve with an orifice from the back side by a spring, And the disk having an opening window communicating with the orifice, the inner peripheral side is held, and A low-speed leaf valve incorporated in a manner to face the lower surface of the opening window, and hydraulic oil from the piston upper chamber via the communication passage is passed through the leaf valve with an orifice and the low-speed leaf valve. It is to release in parallel with the piston lower chamber.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a valve structure of a hydraulic shock absorber according to the present invention will be described with reference to a first embodiment shown in FIG.
In the case of a so-called extension stroke in which the piston rod 102 extends with respect to the cylinder 1, the passage resistance when the hydraulic oil in the piston upper chamber A moves to the piston lower chamber B through the piston valve PV becomes the extension side damping force. On the other hand, in the case of the so-called contraction stroke in which the piston rod 102 descends, the working oil corresponding to the piston rod entry volume of the sealed piston lower chamber B is the outer peripheral passage 106A of the piston 106.
Through the base valve BV attached to the lower end of the cylinder 1, except that the check valve 105 urged by the non-return spring 104 is pushed open and replenished in the piston upper chamber A which becomes negative pressure. Flow out into the tank chamber C, and the passage resistance at this time becomes the compression side damping force. Since the operation as a damping force generation valve is almost the same,
Hereinafter, the piston valve PV will be mainly described. The same parts as those of the conventional technology will be described with the same reference numerals, and the description of the parts having the same effects will be omitted.

A lower part of the piston rod 102 is provided with a spigot part 102A having a diameter smaller than that of the upper part, and a check valve 105, a piston ring 107 and a guide bush 108, which are biased by a valve retainer 103 and a non-return spring 104, are provided there. Mounted piston 106,
The leaf valve 8 with an orifice is sequentially inserted. Finally, screw the piston nut 114 with the spring 113 and the spring seat sub-assembly S112,
Tighten with the specified torque.

Here, the spring seat subassembly S112 includes the disk 110 and the opening window 11 of the disk.
The inner diameter side of the leaf valve 111 for low speed facing the lower surface of 0A and the canzer 109 on the lower surface thereof, which serves as a support point for bending, is fitted and inserted so as to overlap the outer surface of the cylindrical portion of the spring seat 112, and the upper end surface of the cylindrical portion is conical. Is a sub-assembly part fixed by expansion or caulking with a cylindrical pressing jig, and the inner cylinder side is the cylindrical portion 1 of the piston nut 114.
14A is slidably guided to urge the outer peripheral rear surface of the leaf valve 8 with an orifice by a spring 113. The lower surface of the collar of the spring seat 112 is the spring 1
The seating surface receives the biasing force of 13, and the upper surface serves as a stopper for restricting the bending of the very low speed leaf valve 111.

An outer peripheral passage 106A and an inner peripheral passage 106B are formed in the piston 106 which divides the interior of the cylinder 1 into a piston upper chamber A and a piston lower chamber B. An annular opening window 106 is provided on the downstream side of the inner peripheral passage 106B.
C is formed, and the same leaf valve 8 with an orifice as shown in FIG. 3 (B) is urged by the spring 113 through the spring seat subassembly S112 on the outer peripheral back surface to the outer seat surface 106E below the piston. While abutting, the inner peripheral side is sandwiched by the inner seat surface 106D of the lower portion of the piston and the upper end surface of the cylindrical portion 114A of the piston nut that serves as a supporting point for bending, and faces the opening window 106C of the lower portion of the piston. In the so-called very low to low speed range where the piston speed is low and the pressure difference between the opening window 106C at the lower part of the piston and the lower piston chamber B is small, the outer periphery of the leaf valve 8 with an orifice whose outer peripheral back surface is biased by the spring 113 is closed. Has been done.

Since the opening window 106C at the lower portion of the piston communicates with the communication hole 110B of the disc 110 via the orifice 8B of the leaf valve with an orifice, the leaf valve for very low speeds facing the opening window 110A of the disc 110. The outer peripheral side of 111 is pushed open by using the outer diameter of the canzer 109 as a supporting point for bending, and the hydraulic oil is transferred to the piston lower chamber B.
And the damping force in the low to low speed range is generated by the passage resistance at this time. Since the flow rate of the hydraulic oil passing through the orifice 8B is small in the very low speed region, a pressure difference before and after the orifice 8B hardly occurs, but when the leaf valve 111 for the very low speed downstream of the orifice is pushed open, a small flow rate occurs. However, since the passage resistance corresponding to the flexural rigidity is generated, a linear damping force can be obtained.

As the piston speed increases, the flow rate passing through the orifice 8B also increases, and the pressure difference before and after the orifice 8B also increases. As the piston speed approaches the medium speed range,
Since the pressure difference between the opening window 106C in the lower portion of the piston and the lower chamber B of the piston becomes large, the outer periphery of the leaf valve 8 with an orifice biased by the spring 113 is pushed open from the outer seat surface 106E on the lower surface of the piston and the operating oil is released. Flows out into the piston lower chamber B, and due to the passage resistance at this time,
Generates damping force after the medium speed range.

That is, although the upstream leaf valve 8 with an orifice and the downstream low speed leaf valve 111 are structurally assembled in series, the orifice provided in the leaf valve 8 with an orifice increases as the piston speed increases. 8
When the pressure difference before and after B exceeds a set pressure determined by the urging force of the spring 113 and the flexural rigidity of the leaf valve 8 with an orifice, the leaf valve 8 with an orifice is pushed open from the outer seat surface 106E below the piston and damped. Since it operates as a force generation valve, the pressure difference before and after the orifice 8B does not increase further, and even if the piston speed further increases, the flow rate flowing to the very low speed leaf valve 111 becomes constant.

According to this structure, the disk 110, the very low speed leaf valve 111, and the canzer 109 on the lower surface thereof which serves as a supporting point for bending are preliminarily set in the spring seat 11.
Since it can be sub-assembled to 2, it is possible to prevent the bite of the low speed leaf valve from being caught in the prior art. Moreover, the spring seat subassembly S112 can be easily attached to the piston nut 114 because it can be handled as one component, and the piston valve PV can be easily attached to the piston rod inlay portion 102A. Further, since the canzer 109 arranged on the lower surface of the very low speed leaf valve 111 is punched by a die and has an outer diameter having a constant size as a bending support point, the very low speed leaf valve 111 is bent. As a result of the variation in rigidity being reduced, the damping force in the low to low speed range is stabilized.

Next, a second embodiment of the present invention shown in FIG. 2 will be described. The difference from the first embodiment shown in FIG. 1 is that
The inner diameter side of the leaf valve 211 for very low speed, the canzer 209 on the lower surface thereof, which serves as a support point for the flexure, and the valve stopper 212 for restricting the flexure is fitted and inserted so as to overlap the outer surface of the cylindrical portion of the disk 210, and the lower end surface of the cylindrical portion is conical. The disk sub-assembly S210 is formed by expanding the pipe with a flat pressing jig or fixing it by caulking or the like. In the disc subassembly S210, the inner cylinder side is slidably guided by the cylindrical portion 214A of the piston nut, and the outer peripheral rear surface of the leaf valve 8 with an orifice is provided with a spring 21.
Energize with 3. Also a leaf valve with an orifice 8
Like the first embodiment shown in FIG. 1, the inner circumference is held between the inner seat surface 106D of the lower portion of the piston and the upper end surface of the cylindrical portion 214A of the piston nut that serves as a supporting point for the deflection, and the opening window of the lower portion of the piston is held. It faces 106C.

According to this structure, the very low speed leaf valve 211, the canzer 209, and the valve stopper 212 can be sub-assembled to the disk 210 in advance, so that the very low speed leaf valve of the prior art can be used. It is possible to prevent biting in advance. The disc sub-assembly S21 can be attached to the piston nut.
It is easy because 0 can be treated as one component, and the piston valve PV can be easily assembled to the piston rod inlay portion 102A. Further, as in the case of the first embodiment, the canzer 209 arranged on the lower surface of the very low speed leaf valve 211 is punched by the mold and the outer diameter of which the size is constant serves as a bending support point. As a result of the variation in the flexural rigidity of the very low speed leaf valve 211 being reduced, the damping force in the very low to low speed range is stabilized.
The mechanism of generating the damping force in the low to low speed range and the medium speed range and thereafter is the same as that in FIG.

[0025]

In the case of the first embodiment, since the leaf valve for very low speed can be pre-assembled in the spring seat together with the canzer, the leaf valve for very low speed is misaligned when the hydraulic shock absorber is assembled. Therefore, it is possible to prevent the bite from occurring, and prevent the damping force of the hydraulic shock absorber from being defective due to the defective operation of the very low speed leaf valve. Further, in the case of the second embodiment, since the leaf valve for very low speed can be pre-assembled to the disk together with the canzer and the valve stopper, the leaf valve for very low speed is misaligned when the hydraulic shock absorber is assembled. Therefore, it is possible to prevent the bite from occurring, and prevent the damping force of the hydraulic shock absorber from being defective due to the defective operation of the very low speed leaf valve. Further, in both the first and second embodiments, by disposing a canzer having a constant inner diameter dimension serving as a support point for bending on the lower surface of the leaf valve for very low speed,
The damping force in the low speed range can be stabilized. In addition, also in the case of the first and second embodiments, as the spring seat and the disc sub-assembly component, it is possible to measure and select the damping force in a very low speed to low speed range before assembling to the hydraulic shock absorber, so that the hydraulic shock absorber It is possible to reduce the occurrence of defective damping force after assembly in a container.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a hydraulic shock absorber showing a first embodiment of the present invention.

FIG. 2 is a vertical sectional view of a hydraulic shock absorber showing a second embodiment of the present invention.

FIG. 3 is a vertical sectional view of a hydraulic shock absorber according to a conventional technique.

[Explanation of symbols]

 1 Cylinder A Piston upper chamber B Piston lower chamber 8 Leaf valve with orifice 8B Orifice 102 Piston rod 106 Piston 106B Communication passage (inner peripheral passage) 106D Piston inner seat surface 106E Piston outer seat surface 109,209 Kans 110,210 Disc S210 Disc subassembly 110A, 210A Open window provided in disc 111, 211 Leaf valve for very low speed 112 Spring seat S112 Spring seat subassembly 113, 213 Spring 114, 214 Piston nut 114A, 214A Cylindrical part of piston nut 212 Valve Stopper

Claims (4)

[Claims] 1. A piston, which is assembled to a lower end portion of a piston rod and is movably inserted into a cylinder, divides the inside of the cylinder into two oil chambers and generates the oil in a communication passage communicating between the two oil chambers. In a hydraulic shock absorber having a damping force generating mechanism that controls the flow of hydraulic oil to generate a damping force, the damping force generating mechanism is such that the inner seat side of the piston and a piston nut hold the inner peripheral side and the outer peripheral side of the piston. The leaf valve with an orifice that comes into contact with the outer seat surface of the, and downstream of the orifice provided in the leaf valve with the orifice, is slidably guided by the cylindrical portion of the piston nut, The spring seat sub-assembly, which is biased from the back side by a spring, has the cans and the A leaf valve for a fine low speed, which is sandwiched on the inner peripheral side by a disc having an opening window communicating with the orifice of a leaf valve with a refill and is installed in a manner to face the lower surface of the opening window, A valve structure of a hydraulic shock absorber, characterized in that hydraulic oil from an upper chamber of a piston via a passage is released in parallel to a lower chamber of the piston via a leaf valve with an orifice and a leaf valve for very low speed. 2. The spring seat sub-assembly includes a disk having an opening window communicating with the orifice, a canzer serving as a supporting point for bending, and the canzer and the disk facing the lower surface of the opening window of the disk. 2. A hydraulic shock absorber according to claim 1, wherein a leaf valve for a very low speed held in a mode is superposed on the outer surface of the cylindrical portion of the spring seat, and the upper end of the cylindrical portion is fixed by expansion or caulking. Valve structure. 3. A piston, which is assembled to the lower end of a piston rod and is movably inserted into the cylinder, partitions the interior of the cylinder into two oil chambers and creates a communication passage that connects the two oil chambers. In a hydraulic shock absorber having a damping force generating mechanism that controls the flow of hydraulic oil to generate a damping force, the damping force generating mechanism is such that the inner seat side of the piston and a piston nut hold the inner peripheral side and the outer peripheral side of the piston. The leaf valve with an orifice that comes into contact with the outer seat surface of the, and downstream of the orifice provided in the leaf valve with the orifice, is slidably guided by the cylindrical portion of the piston nut, A disc sub-assembly that is biased from the back by a spring is superimposed on the upper side of the valve stopper that regulates bending. In the upper surface of the canzer serving as a support point for the flexure, the inner peripheral side is held by the canzer and a disk having an opening window communicating with the orifice, and the inner surface is sandwiched so as to face the lower surface of the opening window. And a fine low-speed leaf valve, and is configured to release hydraulic oil from the piston upper chamber via the communication passage in parallel to the piston lower chamber via the leaf valve with an orifice and the low-speed leaf valve. The valve structure of the hydraulic shock absorber, which is characterized in that 4. The disc sub-assembly is held by a valve stopper that regulates flexure, a canzer that serves as a support point for flexure, and a face facing the lower surface of the opening window by the canzer and the inner seat surface of the disc. 4. A valve structure for a hydraulic shock absorber according to claim 3, wherein the leaf valve for a very low speed is superposed on the outer surface of the cylindrical portion of the disc and is inserted therein, and the lower end of the cylindrical portion is fixed by expansion or caulking.