JPS5824661B2 - Damping force generator in shock absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a damping force generating device in a shock absorber having a fluid sealed therein.

Some shock absorbers generate damping force by opening a so-called disk valve using fluid pressure corresponding to piston speed.

This type of shock absorber is used as a shock absorber for automobiles to absorb vibrations and improve riding comfort.

Many of this type of shock absorbers are of the telescopic type, and their damping force characteristics are not the same on the expansion side and the compression side, and generally the ratio is about 2:1 to 3:1.

Conventionally, in order to obtain damping force characteristics with such a ratio, separate disc valves that act on the expansion side and disc valves that act on the compression side are provided on both sides of the piston, and the characteristics of each disc valve are adjusted to this ratio. There are two types of disc valves, one in which a single disk valve generates damping force for both expansion and contraction, and its characteristics are adjusted to match the above ratio.

The present invention adopts the latter method, in which the valve retainer is provided so as to be movable within a certain range with respect to the oil field defining member, and in the non-operating state, the valve retainer is at one sliding limit position and at the other sliding limit position. The disk valve is positioned at a certain gap with respect to the sliding limit position, and one peripheral edge of the disc valve is placed on the valve seat of the valve retainer, and the other peripheral edge is placed on the valve seat of the oil field defining member, and the initial deflection is performed. A load is applied to contact the valve retainer, and the valve retainer is urged toward the disk valve side with a spring force smaller than the initial deflection load. During compression, the disk is moved around the contact position of the valve retainer at one sliding limit position as a fulcrum. The valve is characterized by being configured such that when the valve is deflected and extended, the disk valve follows the deflection of the disk valve and is displaced to the other sliding limit position, and then the disk valve is deflected using the valve seat of the oil field defining member as a fulcrum. It is something to do.

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, the inside of a pressure cylinder 1 of a shock absorber body M is divided into oil chambers A and H by a piston 2, which is an oil field defining member, and a piston rod 3 connected to the piston 2 is connected to the inside of the oil chamber A. It penetrates and extends to the outside of the pressure cylinder 1.

An outer cylinder 5 is provided concentrically on the circumference of the pressure cylinder 1, and an oil chamber C is formed between the cylinders 1 and 5, and a through hole 6 provided in the pressure cylinder connects the oil chamber C and the oil. Communicate with room B.

Further, the upper part of the oil chamber C is an air chamber that absorbs changes in volume.

The open ends of both cylinders 1.5 are respectively closed by end plates 7A and 7B, and a fitting 8A for attaching to the vehicle body is attached to the end plate 7A, and also to the end of the rod 3 that protrudes through the end plate IB. A fitting 8B for attaching to the vehicle body is attached.

The piston 2 is equipped with a disc valve structure, and in FIG. 2 showing the details, the piston rod 3 is
Shaft portions 3A and 3B with different diameters are provided at the ends of the shank, and a disc valve guide 9 is fitted into the shaft portion 3A, and this is inserted between the piston 2 and the stepped portion 4A. In addition to being locked, the valve retainer 10 is also sheathed so as to be slidable along the rod 3.

In addition, the piston 2 is fitted into the shaft portion 3B, and this is inserted into the stepped portion 4B.
It is integrally fixed to the rod 3 by being engaged with the rod 3.

Then, the outer peripheral edge 11a of a disc valve 11 made of one or more thin elastic discs fitted into the foot part 9A of the disc valve guide 9 is seated on the annular valve seat 2a of the piston 2 provided on the end face on the side of the oil chamber A. At the same time, the inner peripheral edge 11b of the disc valve 11 is attached to the annular valve seat 10a of the valve retainer 10.
bring it into contact with.

Further, a spring 12 is interposed between the valve retainer 10 and the disc valve guide 9.

In this state, the disc valve 11 is given some initial deflection load and the valve seat 10 of the valve retainer 10
a and the valve seat 2a of the piston 2, and the spring 12 is compressed and the disc valve guide 9
Although the spring force is smaller than the initial deflection load applied to the disc valve 11, it does not apply an initial load to the disc valve 11.

That is, the disk valve 11 is given an initial load by its own thickness t and the distance l between the valve seat 10a of the valve retainer and the valve seat 2a of the piston 2 when the valve retainer 10 is at the upper limit position as shown in the figure. It is.

As described above, the valve retainer 10 applies an initial load to the disc valve 11 in the normal, ie, non-operating state.
The disc valve 11 is held at the upper limit sliding position in contact with the disc valve retainer 9 due to the reaction force, and in this state, the valve seat 10'a and the piston 2 at the lower sliding limit position are held in contact with the disc valve retainer 9. A gap δ is formed between the seat 2b and the seat 2b.

Therefore, the valve retainer 10 can be displaced by δ toward the piston 2 when the disc valve 11 is bent toward the piston 2.

The piston 2 also has an orifice 13 communicating between the oil chambers A and B, an oil passage hole 14, and an annular cavity 16 to which the oil passage hole 14 is connected and allows the disc valve 11 to deflect toward the piston 2 side. is provided.

Next, the operation of the damping force generating device according to the present invention will be explained.

When the piston 2 is extended at a low speed, the oil in the oil chamber A first flows into the oil chamber B through the orifice 13 and generates a damping force.

Then, as the speed of the piston 2 increases, the pressure of the oil in the oil chamber A increases, and the inner circumferential edge 11b of the disc valve 11 begins to bend. slides toward the piston 2 side.

Therefore, as long as the valve retainer 10 is not displaced by δ and comes into contact with the seat 2b of the piston 2, even if the disc valve 11 is bent, the valve retainer 10 and the disc valve 1
No oil passage is formed between the two.

Furthermore, the pressure of the oil in the oil chamber A increases, and the disc valve 1
1 is further bent and the valve retainer 10 comes into contact with the seat 2b of the piston 2, the disc valve 11 is bent for the first time using the valve seat 2a of the piston 2 as a fulcrum, and the disc valve 1
A passage is formed between the valve retainer 1 and the valve retainer 10, and a damping force is generated when the oil passes through this passage.

Furthermore, when acting on the compression side, the oil in the oil chamber B first flows into the oil chamber A through the orifice 13 and generates a damping force.

When the speed of the piston 2 increases, the pressure in the oil chamber B increases, and the outer circumferential edge of the disk valve 11 bends with the valve seat 10a of the valve retainer 10 as a fulcrum. A passage is formed between the piston 2 and the outer peripheral edge of the disc valve 11, spaced apart from the valve seat 2a, and a damping force is generated when the oil in the oil chamber B passes through this passage.

By varying the size of the gap δ between the valve retainer 10 and the piston 2 in a stationary state, the damping force ratio between the expansion side and the compression side can be changed, and the gap δ can be increased. If the damping force ratio becomes large, the opposite is true if the space δ is made small.

FIG. 3 shows another embodiment of the invention.

In this device, an ear portion 2c is provided on the outer circumferential edge of the piston 2 to fit and hold the outer circumferential edge 11a of the disc valve 11, and an ear portion 2c is provided on the inner circumference of the ear portion 2c to provide oil when the outer circumferential edge 11a of the disc valve 11 is bent. Route 1 connecting rooms A and B
4 will be provided.

Further, the shaft portion 3A into which the pub retainer 10 is fitted is provided integrally with the piston 2.

As a result, the disc valve guide 9 shown in FIG. 2 is omitted and a mere seat plate 15 of the spring 12 is provided instead.

Further, 13 is an orifice that functions similarly to the orifice 13 in FIG.

FIG. 4 shows still another embodiment of the present invention.

In this embodiment, the outer peripheral edge 11 of the disc valve 11
a with the valve retainer 10, and also hold the disc valve 1.
This is different from the above two examples in that the inner circumferential edge 11b of the piston 2 is pressed by the valve seat 2a of the piston 2.

In each embodiment, the disc valve structure for generating damping force is provided between the oil chambers A and B, but it goes without saying that it may be provided between the oil chambers B and C.

As described above, the present invention has a very simple configuration, and
The damping force ratio between expansion and compression can be varied by using one disc valve made of thin elastic material, and when the shock absorber operates on one side, that is, on the expansion side, the disc valve flexes and becomes partitioned. Even if an attempt is made to communicate between the chambers divided by the oil field defining member, the chambers separated by the oil field defining member will not communicate until after the valve retainer has been displaced beyond a predetermined value.
There are no sudden fluid pressure fluctuations around the disc valve, and the occurrence of natural vibration of the disc valve can be prevented.

Furthermore, by changing the amount of displacement of the valve retainer, the timing of communication by the disc valve can be controlled, so the damping force ratio during expansion or compression can be set arbitrarily.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a shock absorber to which the device of the present invention is applied, and FIGS. 2, 3, and 4 are enlarged cross-sectional views of essential parts showing one embodiment of the device of the present invention, respectively. 2... Oil field defining member, 10... Valve retainer, 11... Disc valve, δ...
···gap.

Claims (1)

[Claims] 1. In a shock absorber equipped with a disc valve that communicates a space partitioned by a hydraulic defining member through both expansion and contraction deflection, the valve retainer can be displaced within a certain range with respect to the oil field defining member. in the non-operating state, the valve retainer is at one sliding limit position and is positioned at a certain distance from the other sliding limit position, and the one peripheral edge of the disc valve is positioned at one of the sliding limit positions. . A spring force smaller than the initial deflection load is applied to the valve seat of the valve retainer by applying an initial deflection load to the valve seat of the valve retainer and applying an initial deflection load to the other peripheral edge of the valve seat of the oil field defining member. When compressed, the palburi is at one sliding limit position. The disc valve flexes using the contact position of the retainer as a fulcrum,
Further, during expansion, the disc valve follows the deflection of the disc valve and is displaced to the other sliding limit position, and then the disc valve is deflected using the valve seat of the oil field defining member as a fulcrum. . Main device.