JPS5824658Y2 - Buffer valve structure - Google Patents

Description

[Detailed description of the invention] The present invention relates to a valve structure that is installed in a hydraulic shock absorber to generate damping force, and in particular relates to a valve structure that allows the damping force characteristics on the expansion side and compression side to be freely adjusted. be.

Conventional hydraulic shock absorbers generate damping force by applying throttling resistance to the liquid moving between hydraulic pressure chambers separated from each other, and this throttling resistance force is generated by a valve. ing.

Various configurations have been proposed for this type of valve structure, but there is one that uses a leaf valve, which has a simple structure and provides reliable operation and effect, and there are currently many available. It's being used.

A valve structure using this leaf valve has one or two valve bodies formed in an annular shape made of an elastic plate-like member interposed in a communication path that communicates hydraulic pressure chambers that are separated from each other. By deforming in one direction or the opposite direction in response to the reciprocating flow of liquid accompanying the expansion and compression of the shock absorber, a throttling action, that is, a damping action is exerted depending on the degree of deformation.

However, in this configuration, the same leaf valve is deformed by the reciprocating flow of liquid, so the direction of deformation of the leaf valve changes due to the reciprocating flow, but the deformation resistance is almost constant in either direction. Therefore, it has the characteristic that the damping force during expansion and compression is almost the same.

Therefore, if there is a request to make the damping force during compression different from that during extension, such as making the damping force during compression smaller than that during extension, it is necessary to provide separate parts and add a new configuration. This results in a complicated structure and causes problems such as the difficulty of adjusting the damping force.

The present invention was developed in view of the above, and the deformation resistance of the leaf valve body is made to differ depending on the direction of the night flow.
This allows the damping force to be different during expansion and compression, as well as the first. It is an object of the present invention to provide a bulb structure of a shock absorber that allows fine adjustment of the damping force characteristics by appropriately changing the material and dimensions of the second leaf valve.

The present invention will be explained below with reference to embodiments shown in the drawings.

FIG. 1 is a cross-sectional view of a single-tube hydraulic shock absorber 1 having the valve structure of the present invention, particularly the piston portion, and the configuration of its main parts is shown in FIGS. 2 and 3 in its operating state. be.

In the figure, 2 is a cylinder filled with hydraulic oil, 3
4 is a piston that is slidably inserted into the cylinder 2 and separates an upper pressure chamber A and a lower pressure chamber B on both upper and lower sides thereof; This is a piston rod that penetrates the upper pressure chamber A and protrudes liquid-tightly and movably outside the cylinder 2.

The piston 2 has an annular projection 6 on its upper surface, and a communication hole vertically penetrates the piston 2 within the annular projection 6. , 7 are arranged in the circumferential direction.

A relatively thick support 8 and a thin spacer 9 are fitted onto the piston rod 4 so that the end surface of the support 8 forms a shoulder for locking the inner circumference of a leaf valve, which will be described later.
An oil-permeable cap 10 is fitted onto the support 8 and is secured at its flange portion 8a.

Further, a valve disk 11 is slidably fitted to the support 8, and a spring 12 is elastically loaded between the support 8 and the cap 10.
It is biased downward in the figure.

This valve disk 11 has a clamping part 14 projecting in the radial direction from a central collar part 13, and the clamping part 14 is provided with communication holes 15.degree. 15 extending vertically in the circumferential direction.

Note that a slight step is provided between the lower surface of the outer edge of the pinching portion 14 and the lower surface of the collar portion 13.

Between the annular protrusion 6 of the piston and the spacer below the support 8, there are two leaf valves formed of annular elastic plates, namely, a first valve body 16 on the upper side and a second valve body 17 on the lower side. A leaf valve consisting of
(The valve disc 11 is configured to come into elastic contact with the upper surface of the valve disc 11.)

These, 1st. The second valve bodies 16 and 17 are formed to have the same dimensions, and their outer diameters are somewhat smaller than the inner diameter of the cap 10, and their inner diameters are smaller than the outer diameter of the support 8.

And these first. A thin annular spacer 18 with a minute width is interposed between the inner diameter edges of the second valve bodies 16 and 17, so that the leaf valves 16 and 17 are spaced apart by a minute distance from each other. It has become.

Next, the operation of the structure of the present invention having the above configuration will be explained with reference to FIGS. 2 and 3.

FIG. 2 shows a state in which the piston rod 4 and piston 3 move upward and the shock absorber is extended.

In this state, the liquid in the upper pressure chamber A tries to flow through the communication hole 15 of the valve disc 11 as shown by the arrow in the figure.
At this time, the valve disk 11 is moved downward due to the hydraulic pressure difference between the upper and lower portions of the valve disk 11, and first, the lower surface of the collar portion 13 displaces the inner peripheral portion of the leaf valve downward mainly against the bending rigidity of the second valve body IT. Furthermore, when the differential is turned into a dog, the outer peripheral part of the leaf valve is compressed between the piston 3 and the clamping part 14.

At this time, the outer circumferential portion of the first valve body 16 is deflected slightly downward by an amount corresponding to the thickness of the spacer 18 as an initial deflection.

Then, the liquid passing through the communication hole 15 causes the inner circumferential portion of the first valve body 16 to deflect downward, and accordingly, the second valve body 17 is integrally deflected via the spacer 18 by more than the above-mentioned initial deflection. It flows through the gap between the valve disk and the collar portion 13, and then through the communication hole T of the piston and into the lower pressure chamber B.

Therefore, in this operating state, the first. second valve body 16,
A force is required to deflect 17 together, and the resistance force, or damping force, is the dog.

On the other hand, as shown in FIG. 3, when the piston 3 moves downward and the shock absorber is compressed, the liquid in the lower pressure chamber B moves upward through the communication hole 7 of the piston, and first the second valve body 1T Only the outer circumferential portion of the liquid is flexed upward, and it flows into the upper pressure chamber A through between the annular projection 6 and the cap 10.

Therefore, the resistance force at this time is sufficient to deflect only the second valve body 17. Its damping force becomes smaller.

Then, when the hydraulic pressure further increases and the outer periphery of the second valve body 17 is bent upward by more than the distance provided by the spacer 18, the outer periphery of the second valve body 17 becomes the outer periphery of the first valve body 16. Since the liquid flows while contacting the outer circumferential parts of both leaf valves and integrally bending them, a damping force is generated based on the combined bending rigidity of both valve bodies.
Since there is no initial deflection due to the spacer 18, in this case, even if the outer peripheral portion of the first valve body 16 comes into contact with the clamping portion 14, it will only deflect without the initial deflection of the spacer 1. , therefore the damping force is smaller than when it is extended.

Therefore, the difference in damping force during expansion and compression depends on whether the first valve body 16 and the second valve body 17 act together, or whether only the second valve body 17 acts. By appropriately changing the thickness of the valve body 16, the elastic modulus of the material, etc., and changing its flexural rigidity, the damping force during expansion can be changed broadly and minutely without significantly changing the damping force during compression. It becomes possible to do so.

In addition, by changing the bending force of the second valve body 17, the damping force during both compression and expansion can be changed, and the diameter of the communication hole 15 of the valve disk and the step size on both lower surfaces of the collar part 13 and the clamping part 14 can be changed. There is no need to mention that the damping force during extension can be changed somewhat by changing the following.

In summary, the present invention is based on the first piston installed between the support and the piston. Although it has a simple structure that only requires a spacer between the inner circumference of the second leaf valve, it is possible to set the damping force characteristics at the time of expansion and compression of the shock absorber as desired, and the damping force can be adjusted independently. This has the effect that it can be adjusted to

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a piston portion of a shock absorber provided with the valve structure of the present invention, and FIGS. 2 and 3 are partially enlarged views for explaining the operation. 1...Buffer, 2...Cylinder, 3...Piston,
4... Piston rod, 6... Annular projection, 7... Communication hole, 8... Support, 11... Valve disc,
12... Spring, 15... Communication hole, 16... First valve body, 17... Second valve body, 18... Spacer, A, B... Pressure chamber.

Claims (1)

[Scope of utility model registration request] A leaf valve is interposed in the fluid passage between a support having a valve disk elastically mounted on the outer periphery and a piston fixed to the piston rod together with the support, and the flow rate is reduced based on the deflection deformation resistance of the inner and outer peripheries of the leaf valve. In the valve structure of the shock absorber, the leaf valve is slidably interposed between the annular projection of the piston and the support, and the leaf valve First and second valve bodies are formed in an annular shape from an elastic plate material and have an inner diameter smaller than the outer diameter of the support, and are arranged in parallel in the axial direction, and are located on the inner periphery of both valve bodies. 1. A valve structure for a shock absorber, characterized in that an annular spacer is interposed between the two so that the valve disk comes into elastic contact with an outer peripheral portion.