JP3535273B2 - Hydraulic shock absorber valve structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve structure for a shock absorber, and more particularly to a valve structure for a hydraulic shock absorber having a high degree of freedom in setting damping characteristics at low to medium / high piston speeds.

[0002]

2. Description of the Related Art As a conventional hydraulic shock absorber, a piston rod 102 is inserted into a cylinder 101 as shown in FIG.
1. A piston 103 that is in sliding contact with the inner peripheral surface is attached to define two oil chambers S1 and S2. A compression side oil passage 104 and an extension side oil passage 105 are formed in the piston 103.
On both sides of the compression side valve 1 for opening and closing the compression side oil passage 104
06 and extension side valve 10 for opening and closing the extension side oil passage 105
7, the compression side valve 106 is provided with a slit 109a, and the extension side valve 107 has a plurality of plate valves 11 on the seat surface (round surface) 110 side of the piston 103.
There is a structure in which 1,112 and 113 are sequentially stacked.

And, these plate valves 111, 11
2, 113 is formed into a circular shape, and a seat surface 1 for receiving these
10 is formed in a circular shape (annular shape) as shown in FIG. The damping force characteristic in the extension stroke in such a valve structure is that the hydraulic oil in the oil chamber S1 is slit 109 of the compression side valve 106 when the piston speed is low.
When the piston speed is medium speed because the seat surface 110 has a circular shape (annular shape) because a relatively steep damping force characteristic is obtained by flowing from a into the oil chamber S2 through the compression side oil passage 104.
The expansion side valve 10 is operated by the hydraulic oil flowing into the expansion side oil passage 105.
7 is opened, and a relatively gentle damping force characteristic is obtained. When the circular seat surface is used as described above, an inflection point is generated in the damping force characteristic between the low speed region and the medium speed region, and the linear characteristic cannot be obtained.

Therefore, by forming the seat surface into a non-circular shape (non-annular shape) as shown in FIG. 10 (b), the valve is gradually opened even when the piston speed is in the low speed range so that the valve moves from the low speed range. There is also one that is designed to obtain a substantially linear damping force characteristic up to the medium speed range. However, when a non-circular seat surface is used, as can be seen from the figure, the valve opening in the high speed region becomes small and the damping force characteristic becomes relatively steep.

Therefore, as disclosed in Japanese Utility Model Laid-Open No. 60-99341, the shape of the intermediate plate valve 112, which serves as an intermediate seat constituting the valve 107, is shown in FIG. The plate valve 11 that becomes a sub valve by forming an eccentric shape as shown in FIG.
1 and a part of the entire circumference of the plate valve 113 serving as the main valve starts to bend, and then gradually bends along the entire circumference so that there is no inflection point from the low speed region to the medium speed region. Proposed.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
As disclosed in Japanese Patent No. 99341, in a valve structure in which an intermediate seat forming a valve is eccentric, although a damping force characteristic in a medium speed range similar to that of a circular seat surface is obtained, It is difficult to understand the correlation between the seat shape and the generated damping force.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides two oil chambers in a cylinder by a piston provided with a valve member whose inner peripheral portion is supported and a valve seat which receives the valve member. A hydraulic shock absorber, which is defined and has a damping flow path formed by the bending of the valve member according to the pressure difference between these two oil chambers, thereby exerting a damping force on the forward / backward movement of the piston rod with respect to the cylinder. In the valve structure of, the valve member is configured by stacking a sub valve, an intermediate seat, and a main valve from the valve seat side.
The sub-valve and the main valve are annular elastic plates having substantially the same inner and outer diameters, and the intermediate seat is formed with a plurality of radial feet that partially restrict the bending of the sub-valve.

More specifically, the inside of the cylinder is divided into two oil chambers by a piston having a valve member whose inner peripheral portion is supported and a valve seat for receiving the valve member.
In the valve structure of the hydraulic shock absorber, wherein the damping flow path is formed by the bending of the valve member according to the pressure difference between the two oil chambers, so that the damping force acts on the forward / backward movement of the piston rod with respect to the cylinder. An outer round, an intermediate round and an inner round are formed on the valve seat surface of the piston, and the valve member is formed by superposing a sub valve, an intermediate seat and a main valve from the valve seat surface side, and the sub valve and the main valve are An annular elastic plate having substantially the same inner and outer diameters is used.The sub-valve and the main valve are formed with an opening connected to the damping flow path formed between the intermediate round and the inner peripheral round. Forming a plurality of radial feet that partially regulate the deflection of the.

[0009]

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an enlarged sectional view of a piston portion of a shock absorber to which a valve structure according to the present invention is applied, FIG. 2 is an exploded perspective view of the piston portion, and FIG.
(D) is a top view of the component which comprises a valve member.

In the figure, reference numeral 1 is a cylinder, and this cylinder 1
The piston rod 2 is inserted from above in the figure,
A piston 3 that is in sliding contact with the inner peripheral surface of the cylinder 1 is fixed to the tip of the piston rod 2, and the piston 3 defines the inside of the cylinder 1 into two oil chambers S1 and S2.

A compression side oil passage 4 and an extension side oil passage 5 are formed in the piston, and a compression side valve member 6 for opening and closing the compression side oil passage 4 is provided on one surface side (upper surface in FIG. 1) of the piston 3.
The extension side valve member 7 for opening and closing the extension side oil passage 5 is provided on the other surface side of the piston 3.

One side of the piston 3 is a valve seat surface, and an outer round 8, an intermediate round 9 and an inner round 10 are formed on the valve seat surface, and between the outer round 8 and the intermediate round 9. An annular flow path 11 is formed, and an annular flow path 12 is formed between the intermediate round 9 and the inner round 10. Then, the annular flow passage 11 communicates with the compression side oil passage 4, and the annular flow passage 12 extends.
Is in communication with.

The compression side valve member 6 includes a sub valve 13, an intermediate seat 14, a main valve 15 and a valve seat 16.
2 and 3, the sub-valve 13 is made of an annular elastic plate, and nine circular openings 13a are formed around it, as shown in FIGS. 2 and 3.
The intermediate seat 14 is radially formed with four legs 14a for partially restricting the bending of the sub-valve 6, and the main valve 15 is made of an annular elastic plate having the same diameter as that of the sub-valve 13 and is surrounded by three pieces. Is formed with an oval opening 15a. Here, the openings 13a and 15a are formed at locations corresponding to the annular flow path 12 and the extension-side oil path 4 with the radial direction as a reference.

The shape of the intermediate sheet 14 is 4
The shape is not limited to the one provided with two legs, and the shape in which the tips of the four legs 14a are swollen as shown in FIG.
One provided with two legs 14a as shown in (b) or one provided with three legs 14a as shown in FIG. 4 (c).

On the other hand, the extension side valve member 7 includes a sub valve 17,
Intermediate seat 18, main valve 19 and valve seat 2
0 is stacked from the opposite valve seat surface side, the sub-valve 17 and the main valve 19 are made of an annular elastic plate having the same diameter, and the intermediate seat 18 has the same outer diameter as the sub-valve 17 and the main valve 19. Fan-shaped notches 18a are formed at two locations.

The compression stroke of the shock absorber constructed as described above will be described with reference to FIGS. First, before shifting to the compression stroke, as shown in FIG. 5, the lower surface of the sub-valve 13 has an outer round 8, an intermediate round 9 and an inner round 10.
And a channel is not formed except for a portion of the fixed orifice 8b formed in the outer round 8 in close contact with. It should be noted that instead of providing the fixed orifice 8b for extremely low speed in the outer peripheral round 8, an outer peripheral slit valve may be used, or the fixed orifice 8b may be completely closed without providing the fixed orifice 8b.

Next, when the piston speed is low and in the compression stroke, as shown in FIG. 6, the portion of the sub-valve 13 which is disengaged from the foot 14a of the intermediate seat 14 is moved upward by the pressure of the hydraulic oil from the oil chamber S1. Bending, a gap 8a is formed in that portion, and the working oil in the oil chamber S1 is transferred to the oil chamber S through this gap 8a.
2 and a damping force is generated in the gap 8a.

Then, when the piston speed shifts from the low speed state to the medium speed, the deflection of the sub-valve 13 becomes large as shown in FIG. 7, and a gap 9a is formed between the intermediate round 9 and the sub-valve 13. 9a, the sub-valve opening 13a and the main valve opening 15a flow into the oil chamber S2, and a damping force is generated in the gap 9a. Further, as the piston speed increases, the main valve 15 also bends as shown in FIG. 8, and a large damping force is obtained.

Although the action on the compression side is as described above, according to the present invention, the damping force changes smoothly from low speed to high speed, and no inflection point is generated in the graph representing the damping force characteristic.

On the other hand, in the extension stroke of the shock absorber, when the piston speed is low, the working oil in the oil chamber S2 has the opening 15a of the main valve 15 constituting the compression side valve member 6, the opening 13a of the sub valve 13, and A portion corresponding to the fan-shaped notch portion 18a of the intermediate seat 18 of the sub-valve 17 flows through the extension side oil passage 5 and flows into the oil chamber S1 side through a gap formed by bending.

When the piston speed further increases, the main valve 19 also bends and a large damping force is generated. Although the action on the extension side is as described above, the damping force changes smoothly from low speed to medium / high speed, and no inflection point is generated in the graph showing the damping force characteristic.

[0023]

FIG. 11 is a graph comparing the relationship between the damping force characteristic on the compression side and the piston speed. Conventionally, in order to reduce the damping force in the low speed range, the thickness of the check valve is reduced. If it is made smaller, the damping force in the high speed range becomes smaller. Conversely, if the plate thickness of the check valve is made thicker in order to increase the damping force in the high speed range, the damping force in the low speed range also becomes large. According to the method, the damping force in the low speed range can be reduced and the damping force in the high speed range can be increased, and the generated damping force changes extremely smoothly from the low speed range to the high speed range.

As described above, according to the present invention, the sub-valve, the intermediate seat, and the main valve are stacked from the valve seat side to form the valve member, and the sub-valve and the main valve have substantially the same inner and outer diameters. In addition to being composed of an annular elastic plate, the intermediate seat has a plurality of radial feet that partially regulate the deflection of the sub-valve, so it is almost linear from the low speed range to the medium speed range, and at the high speed range it is the original. A damping force characteristic determined by the seat surface is obtained.
Further, it becomes easy to grasp the correlation with the damping force generated by the number of legs of the intermediate sheet and the opening angle, and it is possible to secure the degree of freedom in setting the damping characteristics.

[0025]

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of a piston portion of a shock absorber to which a valve structure according to the present invention is applied.

FIG. 2 is an exploded perspective view of the piston portion.

3A to 3D are plan views of parts constituting a valve member.

4A to 4C are plan views showing another embodiment of the intermediate sheet.

FIG. 5 is a view showing a state before the compression side valve member is actuated.

FIG. 6 is a diagram showing an operation of a compression side valve member in a low speed range.

FIG. 7 is a diagram showing the action of the compression side valve member in the medium speed range.

FIG. 8 is a view showing the action of the compression side valve member in a high speed range.

FIG. 9 is an enlarged sectional view of a piston portion of a shock absorber to which a conventional valve structure is applied.

10A to 10C are plan views of a conventional sheet surface shape and an intermediate sheet.

FIG. 11 is a graph showing damping force characteristics.

[Explanation of symbols]

1 ... Cylinder, 2 ... Piston rod, 3 ... Piston, 4
... compression side oil passage, 5 ... extension side oil passage, 6 ... compression side valve member, 7
... extension side valve member, 8 ... outer round, 8a, 9a ... gap, 9 ... intermediate round, 10 ... inner lined, 11, 1
2 ... Annular flow path, 13, 17 ... Sub valve, 13a, 1
5a ... opening, 14,18 ... intermediate sheet, 14a ... foot, 1
5, 19 ... Main valve, S1, S2 ... Oil chamber.

Claims (2)

(57) [Claims] 1. A piston provided with a valve member whose inner peripheral portion is supported and a valve seat for receiving the valve member defines the inside of a cylinder into two oil chambers, and a pressure difference between the two oil chambers is defined. In the valve structure of the hydraulic shock absorber, in which the damping flow path is formed by the bending of the corresponding valve member, the damping force acts on the forward / backward movement of the piston rod with respect to the cylinder, and the valve member includes a sub valve and an intermediate seat. A main valve and a main valve are superposed from the valve seat side, the sub-valve and the main valve are made of an annular elastic plate having substantially the same inner and outer diameters, and the intermediate seat has a radial shape that partially restricts the deflection of the sub-valve. A valve structure for a hydraulic shock absorber having a plurality of legs formed therein. 2. A cylinder provided with a piston having a valve member whose inner peripheral portion is supported and a valve seat for receiving the valve member defines two oil chambers in the cylinder, and a pressure difference between the two oil chambers is defined. In the valve structure of the hydraulic shock absorber in which the damping flow path is formed by the flexure of the valve member according to the above, a damping force is applied to the forward / backward movement of the piston rod with respect to the cylinder. A round, an intermediate round and an inner peripheral round are formed, and the valve member is configured by stacking a sub valve, an intermediate seat and a main valve from the valve seat surface side.
The sub-valve and the main valve are made of an annular elastic plate having substantially the same inner and outer diameters, and the sub-valve and the main valve are formed with an opening that is connected to the damping flow path formed between the intermediate round and the inner circumferential round. Further, the valve structure of the hydraulic shock absorber, wherein a plurality of radial feet are formed on the intermediate seat to partially restrict the bending of the sub-valve.