JPH058352Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a shot absorber, and in particular,
The present invention relates to an improvement in a shock absorber that can effectively prevent cavitation and swishing noise during expansion and contraction.

[Conventional technology]

In general, a shock absorber is designed so that when the piston moves up and down in the cylinder, a damping force is generated on either or both of the expansion and expansion sides by a predetermined damping valve, and the damping force at that time is In the medium to high speed range of the piston speed, the damping force is generated by the valve characteristics, and in the low speed range of the piston speed, the damping force is generated by the orifice characteristics.

As a structure capable of generating a damping force having an orifice characteristic in a low piston speed range, the structure shown in FIGS. 3 and 4, for example, has been proposed.

That is, FIG. 3 shows the piston part 2 in the cylinder 1.
This is a damping force generation structure with orifice characteristics, but this structure is disposed at the upper end of the piston body 2a and allows the hydraulic oil to flow into the inner port 2b of the piston body 2a.
The notch 2e formed in the check valve 2d that prevents the flow of hydraulic oil into the outer port 2c of the piston 2 reduces the rebound damping in the low speed range when the piston 2 moves up inside the cylinder 1. It is assumed that it is formed so as to enable the generation of force.

Further, FIG. 4 shows a damping force generating structure with orifice characteristics in the base valve part 3 in the cylinder 1, and this structure is arranged at the upper end of the valve case 3a and is applied to the inner port 3b of the valve case 3a. A stamped orifice formed in the seat portion 3e at the upper end of the valve case 3a adjacent to the check valve 3d allows hydraulic oil to flow in, but prevents hydraulic oil from flowing into the outer port 3c from the valve case 3a. 3f, the piston part is connected to cylinder 1.
The structure is such that it is possible to generate a compression damping force in a low speed range when descending inside the vehicle.

Therefore, by appropriately setting the flow path area of the notch 2e in the check valve 2d and the embossing orifice 3f in the seat part 3e,
This makes it possible to generate damping force in the low speed range of the desired piston speed.

[The problem that the idea attempts to solve]

However, in any of the above-mentioned proposals, cavitation and swiss noise are generated when a damping force with desired orifice characteristics is generated.

That is, when the notch 2e in the check valve 2d and the upstream side of the stamping orifice 3f in the seat part 3e become high-pressure sides, the high-pressure oil flows downstream through the notch 2e or the stamping orifice 3f, respectively. This will flow in and generate the desired low-speed damping force, but if the high-pressure oil flows out all at once to the low-pressure side, which is the downstream side, a so-called injection state of the hydraulic oil will occur. cavitation occurs,
Moreover, a swiss sound is also generated.

Furthermore, the above-mentioned cavitation and swiss noises become more noticeable when the flow path area of the orifice is made extremely small in order to increase the damping force in the low speed range.

Therefore, an object of the present invention is to provide a new shock absorber having a structure that eliminates the risk of cavitation or swishing noise when generating damping force in the low piston speed range using orifice characteristics.

[Means for solving problems]

In order to solve the above problems, the shock absorber according to the present invention has a port opening window at the upper end of the valve seat member that allows the upper end of the outer port bored in the valve seat member to open. In addition, in the shock absorber having a check valve consisting of a leaf valve disposed so as to close the port opening window from above, the valve seat member has an upper end opening at an upper end of the valve seat member. The valve seat member has a recess that is bored and arranged on the same circumference as the port opening window, and the recess is formed through a radial stamped orifice formed in the seat portion of the valve seat member. The check valve is characterized in that it communicates with the oil chamber above the check valve, and also communicates with the adjacent port opening window via a circumferential communication stamped orifice formed in the seat portion. be.

[Effect]

When the oil chamber above the check valve is on the high pressure side, the hydraulic oil from the high pressure side oil chamber flows into the recess through the stamped orifice and is depressurized in the recess, and the reduced pressure is activated. Oil flows into the port opening window through the communication stamped orifice in the seat section and flows out into the low pressure side oil chamber, so high pressure hydraulic oil from the high pressure chamber is injected into the low pressure side oil chamber. This prevents the air from flowing into the air in an unsteady condition, and cavitation and swishing noises are no longer generated.

〔Example〕

Hereinafter, the present invention will be explained based on the illustrated embodiments.

1 and 2 show the structure of a base valve part of a shock absorber according to an embodiment of the present invention, in which a base valve part 3 in a cylinder 1 is disposed outside the cylinder 1 and Outer tube 1 that partitions and forms a reservoir chamber C between
The valve case 30 is sandwiched between the upper surface of the bottom member 11 fitted into the inner periphery of the lower end of the valve case 30 and the lower end of the upper cylinder 1, and serves as a valve seat member.
has an inner port 30a and an outer port 30b, and has a port opening groove 30c on the inner peripheral side of its upper end, and a port opening window 30d and a recessed pressure reducing hole 30e on the outer peripheral side. and,
A damping valve 31 as a pressure side valve is adjacent to the lower end of the inner port 30a, and includes the port opening groove 30c, the port opening groove 30d and the pressure reducing hole 30.
A check valve 32 is disposed to close the valve e from above.

The damping valve 31 is a stacked annular leaf valve, and is interposed on the outer periphery of the lower end of the set pin 33 that passes through the center of the valve case 30 so that the inner end is fixed and the outer end is free. and is fixed by caulking the lower end of the set pin 33.

The check valve 32 is an annular leaf valve, but in this embodiment, it has a notch 32a on the inner circumferential side, so that an oil chamber above the check valve 32 (an oil chamber below the piston) can be connected to the check valve 32. The hydraulic oil is formed so as to flow into the inner port 30a through the notch 32a on the inner peripheral side.

Therefore, in this embodiment, the valve case 3
The port opening window 30d and pressure reduction hole 30e formed at the upper end of
The following structure allows hydraulic oil to flow into the port opening window 30d from the oil chamber above the check valve 32.

That is, the pressure reduction hole 30e and the port opening window 3
0d is a valve case 30 which is a valve seat member.
It is formed by sheet parts 30f, 30g, and 30h that project from the upper end (see Fig. 2), and the sheet parts 30f, 30h that define the decompression hole 30e are stamped. Orifice chair 3
0i and a communication embossing orifice 30j are formed. Then, a stamping orifice 30i formed in the seat portion 30f on the outer peripheral side
It is assumed that the pressure reduction hole 30e and the oil chamber above the check valve communicate with each other through the pressure reduction hole 30e, and the pressure reduction hole 30e and the port opening window 30d communicate with each other through the stamped orifice 30j formed in the seat portion 30g.

Therefore, in this embodiment, the above-mentioned embossing orifices 30i and 30j form a so-called orifice. And the said embossing orifice 30
The multi-stage orifice consisting of i and 30j generates a compression side damping force with desired orifice characteristics in the low piston speed range during the compression side stroke when the piston part descends in the cylinder 1, and also generates a compression side damping force with desired orifice characteristics. The hydraulic oil from the lower chamber serving as a side oil chamber flows through the stamping orifice 30i into the pressure reducing hole 30e and is depressurized, and then passes through the stamping orifice 30j to the port opening window 30d.
As a result, the fuel flows into the reservoir chamber C, which is the low-pressure side, and does not flow out to the reservoir chamber C side, which is the low-pressure side, exhibiting an injection state while remaining at high pressure.

It goes without saying that the compression damping force in the medium and high piston speed range is generated by the front damping valve 31.

Although the configuration in the above embodiment is presented as a structure that generates a compression damping force in the base valve part, it is of course possible to use a structure that generates a rebound damping force in the piston part. be.

[Effect of idea]

As described above, according to the present invention, the recess communicates with the high-pressure side oil chamber via the stamped orifice, and also communicates with the port opening window via the communicating stamped orifice, so that the low speed range of the piston speed due to the orifice characteristics When generating damping force, the hydraulic oil from the high pressure side is not suddenly leaked to the low pressure side, so when the hydraulic oil leaks from the high pressure side, the injection state of the hydraulic oil will not be changed in the future, causing cavitation and swishing noise. This has the advantage of eliminating the risk of occurrence.

Furthermore, according to the present invention, since the recess is disposed on the same circumference as the port opening window, there is no need to bulge the valve seat member outward, and the piston is required to reduce the diameter of the shock absorber in recent years. There is also the effect that it can be easily implemented on the valve case in the main body or base valve section.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view partially showing a shock absorber according to an embodiment of the present invention, Fig. 2 is a top end view of a valve case which is a valve seat member, and Figs. FIG. 3 is a longitudinal sectional view partially showing the shock absorber. 1...Cylinder, 3...Base valve part, 30
...Valve case, 30b...Outside port, 30
d... Port opening window, 30e... Decompression hole, 30
f, 30g... Seat portion, 30i, 30j... Communication stamped orifice, 32... Check valve.

Claims (1)

[Scope of utility model registration request] A leaf valve that has a port opening window at the upper end of the valve seat member that allows the upper end of an outer port formed in the valve seat member to open, and is arranged so as to close the port opening window from above. In the shock absorber having a check valve, the valve seat member is bored so that its upper end opens at the upper end of the valve seat member, and is disposed on the same circumference as the port opening window. a recess formed in the valve seat member, the recess communicating with the oil chamber above the check valve via a radial stamped orifice formed in the seat portion of the valve seat member; What is claimed is: 1. A shock absorber characterized in that the shock absorber is connected to an adjacent port opening window through a circumferential communication engraved orifice.