JPH0346267Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Industrial application field) The present invention relates to a valve structure for a hydraulic shock absorber.

(Problems to be solved by conventional techniques and ideas) A piston with a rod connected thereto is slidably fitted into a cylinder filled with hydraulic oil, and between the piston and a valve seat provided on the outer periphery of the piston rod. A valve structure of a hydraulic shock absorber is known in which a leaf valve having a plurality of annular elastic bodies stacked on top of each other is interposed, and a damping force is generated by the deflection resistance of the leaf valve.

In a valve structure with such a configuration, there is one in which a plurality of annular elastic bodies provided between the piston and the valve seat have the same inner diameter and different plate thicknesses,
The relationship between piston speed and damping force of a hydraulic shock absorber equipped with this valve structure is as shown in FIGS. 3 and 4. FIG. 3 shows the change in the damping force due to the change in the number of elastic bodies, in which the number of elastic bodies is small in A, and increases in numbers B and C. Figure 4 shows the change in damping force due to changes in the plate thickness of the elastic body.
The thickness of the plate increases as it becomes C'. Further, as is clear from FIGS. 3 and 4, the damping force of the shock absorber having the above-mentioned valve structure is directly proportional to the piston speed.

By the way, it is generally desirable for a vehicle to have a soft feeling on flat roads and a hard and stable feeling on rough roads.
For this reason, it is desirable for a vehicle shock absorber to generate a low damping force when the piston speed is low, and a high damping force when the piston speed is high.

Therefore, a hydraulic shock absorber valve structure with progressive characteristics that generates a lower damping force at low piston speeds and an even higher damping force at high piston speeds was desired.

On the other hand, in the conventional valve structure mentioned above, there is almost no gap between the elastic body and the piston rod, especially between the elastic body with the smallest inner diameter and the piston rod, so even when the piston slides, the hydraulic oil does not flow. There was a risk that the valve seat would not slide smoothly because it did not hit the valve seat directly. Therefore, it was desired to have a valve structure in which the hydraulic oil directly hits the valve seat when the piston slides, allowing the valve seat to slide smoothly.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a method in which a piston with a rod connected thereto is slidably fitted into a cylinder filled with hydraulic oil, and a piston is provided between the piston and the outer periphery of the piston rod. A leaf valve with multiple annular elastic bodies stacked on top of each other is inserted between the valve seat and the valve seat.
In the valve structure of the hydraulic shock absorber in which damping force is generated by the deflection deformation resistance of the leaf valve, the plate thickness of the plurality of elastic bodies is increased from one located on the piston side to one located on the valve seat side. The inner diameter of the plurality of elastic bodies is gradually increased from those located on the valve seat side to those located on the piston side, and between the inner diameter part of the leaf valve closest to the valve seat and the outer periphery of the rod. It is characterized by providing a gap of a predetermined width.

(Function) The damping force of the hydraulic shock absorber can be set higher when the piston speed is high and lower when the piston speed is low, and progressive characteristics can be obtained. Furthermore, since the hydraulic oil directly hits the valve seat when the piston slides, the valve seat can slide smoothly.

(Embodiment) A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a half-cut vertical cross-sectional view of the valve structure of a hydraulic shock absorber according to the present invention, where 1 is a hydraulic shock absorber, 2 is a cylinder filled with hydraulic oil, and the cylinder 2
By slidably fitting the piston 3 therein, a chamber S1 and a chamber S2 are formed in the cylinder 2, and one end of a piston rod 5 is fixed to the piston 3 with a nut 4.

A small diameter portion 5a is formed directly below the piston 3 of the piston rod 5, and the inner diameter portion 8a of the cap 8 is held between the supports 6 and 7 fitted to the small diameter portion 5a, and the upper end of the cylindrical portion 8b of the cap 8 is connected to the outer circumference of the piston 3. to be locked. Then piston 3 and cap 8
A chamber S3 is formed by the space surrounded by the piston 3, and this chamber S3 communicates with the chamber S2 through the communication hole 3a formed in the piston 3 on the one hand, and the cap 8 on the other hand.
It communicates with the room S1 through a window 8c provided in the room.

A valve seat 9 is fitted into the support 6 so as to be slidable in the vertical direction, and a flow passage 9a is provided in the valve seat.
A spring 10 is elastically mounted between the stepped portion 9b formed at the lower part of the valve seat 9 and the cap 8, and the elastic force of the spring 10 always pushes the valve seat 9 upward, that is, toward the piston 3 side. to strengthen

On the other hand, the piston 3 and the valve seat 9 in the chamber S3
A leaf valve 11 in which a plurality of annular elastic bodies 11a are stacked is interposed between them. The leaf valve 11
As is clear from FIG. 1, the elastic bodies 11a... are thicker and have a larger inner diameter as they are located closer to the piston 3, and gradually become thinner and have a smaller inner diameter as they are closer to the valve seat 9. It's summery. Further, a gap S of a predetermined width is provided between the inner diameter portion of the elastic body 11a located closest to the valve seat 9 and the outer periphery of the support 6.

In addition, 12 in the drawing is a seal member provided between the piston 3 and the cylinder 2.

In the above, the piston 3 and the piston rod 5
moves downward and the hydraulic shock absorber 1 is compressed, the hydraulic oil in the chamber S1 passes through the flow path 9a of the valve seat 9 from the window 8c of the cap 8, pushes up the leaf valve 11, and pushes the leaf valve 11 upward. the chamber S2 through the flow path 3a of the piston 3.
flows into. At this time, the hydraulic oil causes the leaf valve 11 to flex, thereby generating a damping force.
In the present invention, the elastic bodies 11a... are made thinner and have smaller inner diameters as they are located closer to the valve seat, and gradually increase in thickness and inner diameter as they are closer to the piston 9. The damping force characteristic curve of the shock absorber 1 can be made as shown in FIG. In other words, it is possible to obtain a progressive characteristic curve that is gentle in the low piston speed range and increases greatly as the piston speed increases. This damping force is lower in the low piston speed range and higher in the high speed range compared to conventional piston speeds, so it provides a soft feeling on flat roads and a hard and stable feeling on uneven roads when the vehicle is running. Therefore, running stability can be increased.

On the other hand, when the piston 3 and the piston rod 5 move upward and the hydraulic shock absorber 1 expands, the hydraulic oil in the chamber S2 flows into the chamber S3 through the flow passage 3a of the piston 3, and the flow pressure causes the leaf valve 11 , the valve seat 9 is pushed down against the elastic force of the spring 10, and the leaf valve enters the chamber S1 through the gap created between the piston 3 and the leaf valve 11 and the window 8c of the cap 8. At this time, a damping force is generated by pushing down the valve seat 9 against the elastic force of the spring 10. By the way, in the present invention, a gap S of a predetermined width is provided between the inner diameter part of the elastic body 11a located closest to the valve seat 9 and the outer periphery of the support 6, so that when the hydraulic shock absorber 1 is extended, that is, the piston 3, the hydraulic oil in the chamber S2 follows the sliding movement of the piston 3 and comes into direct contact with the valve seat 9. This allows the valve seat 9 to move downward more smoothly.

(Effects of the invention) As described above, according to the invention, the damping force of the hydraulic shock absorber is further increased when the piston speed is high.
When the piston speed is low, it can be set even lower and progressive characteristics can be obtained.
Therefore, when the vehicle is running, a soft feeling can be obtained on a flat road surface, and a hard and stable feeling can be obtained on an uneven road surface, thereby increasing running stability.

Further, since the hydraulic oil directly hits the valve seat when the piston slides, it is possible to obtain effects such as smoother sliding of the valve seat.

[Brief explanation of drawings]

Fig. 1 is a half-cut longitudinal sectional view of the valve structure of the hydraulic shock absorber according to the present invention, Fig. 2 is a diagram showing the damping force characteristics of the same valve structure, and Figs. 3 and 4 are the damping force characteristics of the hydraulic shock absorber. FIG. In addition, in the drawing, 2 is a cylinder, 3 is a piston, and 4 is a cylinder.
9 is a piston rod, 9 is a valve seat, 11 is a leaf valve, 11a is an elastic body, and S is a gap.

Claims (1)

[Claims for Utility Model Registration] A piston with a piston rod connected thereto is slidably fitted into a cylinder filled with hydraulic oil, and a plurality of annular elastic rings are provided between the piston and a valve seat provided on the outer periphery of the piston rod. In the valve structure of a hydraulic shock absorber in which a leaf valve having overlapping bodies is interposed and a damping force is generated by the deflection deformation resistance of the leaf valve, the plate thickness of the plurality of elastic bodies is adjusted toward the piston side. The inner diameters of the plurality of elastic bodies are formed to gradually become smaller from those located on the valve seat side to those located on the piston side, and the inner diameters of the plurality of elastic bodies are gradually increased from those located on the valve seat side to those located on the piston side, A valve structure for a hydraulic shock absorber, characterized in that a gap of a predetermined width is provided between an inner diameter part of an elastic leaf valve and an outer peripheral part of a rod.