JPH0354995Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a valve seat of a piston against which a leaf valve abuts.

(Prior Art) FIG. 5 shows one end surface of a conventional piston, and FIG. 6 shows a longitudinal section of a part of the same piston.
is formed, and to explain the extension side flow path 51, one end opening of the extension side flow path 51 is a pressure receiving part 54 defined by the valve seat 53, and this pressure receiving part 54 is connected to a plurality of leaves. Valve 55a
It is closed by a valve 55 which overlaps...

During the extension, the valve 55 is bent upward by the hydraulic pressure, opening the flow path 51 and allowing the hydraulic oil to flow into the piston 5.
The oil flows from one oil chamber defined by 0 into the other oil chamber.

(Problems to be Solved by the Invention) In the conventional piston described above, the widths of the seat surfaces 53a of the valve seats 53 are equal. On the other hand, since the center of the valve 55 is fixed to the piston 50, if the valve 55 warps during compression, the distance between the valve 55 and the seat surface 53a will be smaller on the radially inner side than on the radially outer side. Become. As a result, the flow path opened by the warping of the valve 55 causes a large pressure difference in the radially inner portion of the valve 55, as shown in FIG.

When a large pressure difference occurs, the flow rate increases, cavitation occurs in the radially inner portion of the valve 55, and the durability of this portion decreases and it becomes easily damaged.

(Means for Solving the Problems) In order to solve the above problems, the present invention aims to reduce the width of the seat surface of the portion of the seat surface that the leaf valve contacts, where the radially inner part of the leaf valve contacts, to the outer part. It was made to be larger than the width of .

(Function) The width of the part of the valve seat surface where the radially inner side of the leaf valve contacts is increased, which increases the length of the flow path in this part, increases viscous resistance, reduces flow velocity, and makes cavitation less likely to occur. Become.

(Example) An example of the present invention will be described below based on the accompanying drawings.

Fig. 1 is a cross-sectional view of a main part of a shock absorber to which a valve seat according to the present invention is applied, and Fig. 2 is an end view of a piston. A piston 3 that slides on the inner circumferential surface of the cylinder 1 is fixed to the upper end of the cylinder 1 by a nut 4.

The piston 3 has an extension side passage 5 and a compression side passage 6.
is formed. The extension side flow path 5 and the compression side flow path 6 have substantially the same shape, although their upper and lower shapes are reversed. A pressure receiving part 8 surrounded by a valve seat 7 is formed at the upper end of the extension side flow path 5, and this pressure receiving part 8 is closed by a valve 9 made up of a plurality of stacked leaf valves 9a. Further, a pressure receiving part is similarly formed at the lower end of the compression side flow path 6 by a valve seat, and this pressure receiving part is connected to the leaf valve 10.
It is closed by the valve 10 that overlaps the valves a.

Here, as shown in FIG. 2, the width of the valve seat 7 forming the pressure receiving part 8 is the width of the radially inner part 7a.
T ₁ is made larger than the width T ₂ of the radially outer portion 7b.

In the above, when stretched, the outer part of the valve 9 warps more than the inner part as shown in FIG. Since the width T ₁ of the portion 7a is large, the length of the flow path in the inner portion 7a becomes longer, so viscous resistance increases, the flow velocity in this flow path becomes slower, and cavitation does not occur.

FIG. 4 is a view similar to FIG. 2 showing another embodiment.
In this embodiment, the outer wall is made non-parallel so that the width of the inner portion 7a is increased.

(Effects of the invention) As explained above, according to the invention, in a piston equipped with a leaf valve, the width of the portion of the valve seat formed on the piston that is in contact with the radially inner side of the leaf valve is increased. So,
When the leaf valve warps and the flow path is revised by hydraulic pressure, the length of the flow path formed between the radially inner part of the leaf valve and the valve seat increases, viscous resistance increases, and the flow velocity decreases. Cavitation is less likely to occur, and the durability of the radially inner portion of the valve, which was conventionally prone to damage, is improved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the main part of a shock absorber to which the valve seat according to the present invention is applied, Fig. 2 is a view showing the end face of the piston, Fig. 3 is a sectional view of the main part of the piston, and Fig. 4 is another embodiment. FIG. 5 is an end view of a conventional piston, and FIG. 6 is a sectional view of a main part of the conventional piston. In the drawing, 3 is the piston, 5 and 6 are the flow paths, 7 is the valve seat, 8 is the pressure receiving part, 9 is the valve, T ₁ is the width of the seat surface on the radially inner side, and T ₂ is the seat on the radially outer side. It is the width of the surface.

Claims (1)

[Scope of utility model registration request] In a piston in which one end opening of a flow path formed in the piston is closed with a leaf valve, the width of the valve seat surface that the leaf valve comes into contact with is the width of the part that the radially inner part of the leaf valve contacts with the radially outer part. A piston valve seat characterized by having a width larger than the width of the part where the two parts come into contact.