JPH0446101Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a damping force adjustment mechanism for a shock absorber that controls damping force depending on the stroke of a piston.

(Prior art) As a damping force adjustment mechanism for this type of shock absorber, the fourth
What is shown in the figure is conventionally known.

The shock absorber shown in FIG. 4 is provided with a cylinder 1 and an inner tube 2, and an oil reservoir chamber 3 is formed between the cylinder 1 and the inner tube 2.

A piston 4 is slidably installed inside the inner tube 2, and a rod 5 of the piston 4 is made hollow. A hollow pipe 7 is erected on a base member 6 provided at the lower end of the inner tube 2, and an auxiliary piston portion 8 formed at the tip of the hollow pipe 7 is made to face inside the rod 5.

Further, the piston 4 is also provided with a seal member 9 that slides into contact with the hollow pipe 7, and a control pressure chamber 10 is formed between the seal member 9 and the auxiliary piston portion 8.

When the piston 4 rises from the illustrated state, the hydraulic oil in the rod side chamber 11 flows out into the bottom side chamber 12 via the orifice 4a formed in the piston 4, but the excess flow flows through the next oil passage. The water flows to the bottom side chamber 12 via the water. That is, Rod5
Flows into the bottom side chamber 12 via the communication hole 13 formed in → control pressure chamber 10 → damping orifices 14, 15 formed in the hollow pipe 7 → hollow pipe 7 → damping port 16 formed at the lower end of this hollow pipe 7 .

When the piston 4 further rises, the lower damping port 15 is closed by the seal member 9, so that the hydraulic oil that has flowed into the control pressure chamber 10 passes only through the upper damping port 14 and enters the hollow pipe 7. flows to Therefore, when the lower damping port 15 is closed, the damping force is greater than when it is open.

As mentioned above, the substantial opening area of the damping port is controlled depending on the moving position of the piston 4, that is, its stroke, so the damping force is controlled depending on the stroke of the shock absorber. .

(Problems to be Solved by the Present Invention) In the conventional shock absorber as described above, the sliding resistance between the auxiliary piston part 8 and the seal member 9 becomes large, and the responsiveness deteriorates accordingly. There was a problem in that the hydraulic oil became contaminated due to wear and other factors, deteriorating the performance of the shock absorber.

In addition, in order to reduce the above-mentioned sliding resistance, it is possible to provide an appropriate clearance in the auxiliary piston section 8 and the seal member 9, but in this case, oil leakage from the control pressure chamber 10, etc. Problems such as damping force characteristics becoming inconsistent occur.

The object of this invention is to provide a shock absorber in which the action of the damping force adjustment mechanism does not affect the damping characteristics.

In order to achieve these objectives,
106388 and Japanese Utility Model Application No. 106388 and Utility Model Application No. 1987-72960, however, these devices arrange a suspension spring and a detection spring in series, and apply a load to the suspension spring that exceeds the initial set load of the detection spring. When the sensor spring is applied, the detection spring is deflected, and the damping force is changed by the amount of deflection.

However, in these conventional devices, since the detection spring is a coil spring, in order to keep the suspension spring and the detection spring in a balanced state, it is necessary to make the detection coil spring larger in the longitudinal direction. This creates a need for the control rod to move a large amount, leaving the problem that the control section itself becomes larger.

(Means for solving the problem) In order to solve these problems, this invention has a damping force generating valve that drains the hydraulic oil in the chamber that contracts according to the compression stroke of the piston into the oil reservoir chamber, and a damping force generating valve that is fitted on the outer periphery of the cylinder. a transmission plate disposed between the spring bearing and the suspension spring;
A detection spring made of a disc spring that is deflected by the spring force when the suspension spring is compressed is arranged between the transmission plate and the spring receiver, and the throttling resistance of the damping force generating valve is increased according to the amount of deflection of the detection spring. The present invention is characterized in that the control rod for controlling the transmission is in contact with the transmission plate.

(Operation of the present invention) The detection spring deflects in response to the spring force when the suspension spring contracts to the left, that is, the stroke of the piston, but since this detection spring is composed of a disc spring, a small amount of deflection of the detection spring The set pressure of the damping force generating valve is controlled. Therefore, the damping force characteristics are controlled depending on the stroke of the piston.

(Effects of the present invention) As mentioned above, since the throttling resistance of the damping force generating valve is adjusted by the amount of deflection of the suspension spring, it goes without saying that there is no sliding contact part as in the prior art. When adjusting the throttling resistance of the damping force generating valve, the movement of the control rod can be reduced, and the control section can be made smaller.

(Embodiment of the present invention) In the first embodiment shown in FIG. 1, a tube 17 is provided outside the cylinder S, and an oil reservoir chamber 18 is formed between the cylinder S and the tube 17.
A piston 19 is slidably installed inside the cylinder S, and the piston 19 divides the inside of the cylinder S into a rod side chamber 20 and a bottom side chamber 21.

A rod 22 provided on the piston 19
tube 1 while guiding it to the bearing 23.
It is made to protrude outward from 7.

A base valve 24 is provided at the lower end of the cylinder S as described above, and the bottom side chamber 21
When the hydraulic oil from the base valve 24 passes through the base valve 24, a predetermined throttling resistance is applied, and in the opposite case, a free flow state occurs.

When the hydraulic oil in the bottom side chamber 21 passes through the base valve 24, it flows into the flow path 26.

This flow path 26 communicates with the oil reservoir chamber 18 via a damping force generating valve V, and the structure of this damping force generating valve V is as follows.

That is, a port 28 communicating with the flow path 26 is formed in the valve case 27 provided on the side surface of the tube 17, and a seat portion 28 of this port 28 is formed.
A is opened and closed using a poppet 29.

Further, one end of the control rod l is exposed to the valve case 27, and the control rod l
and a control spring 30 between the poppet 29 and the poppet 29.
is interposed.

Furthermore, this control rod l includes a return spring 31.
However, this return spring 31 is connected to a stepped portion 32 formed on the valve case 27 and the control rod l.
It is interposed between the spring receiver 33 provided in

The control rod 1 as described above is slidably supported by a bearing 34, and has its other end protruding outward from the valve case 27, and a transmission plate 35 is brought into contact with the protruding end.

The transmission plate 35 has a suspension spring 36
It is made to be able to slide freely on the cylindrical portion 37a of the spring receiver 37, and to cover an annular recess 37b formed in the spring receiver 37.

A dish-shaped detection spring b is provided in the annular recess 37b of the spring receiver 37, and normally the transmission plate 35 is kept in a slightly pushed-up state.

When the piston 19 descends and the pressure in the bottom chamber 21 increases, the hydraulic oil in the bottom chamber 21 passes through the base valve 24 and flows out.

When the hydraulic oil in the bottom side chamber 21 passes through the base valve 24 in this manner, flow resistance is applied to the flow at that time, and a desired damping force is generated. The hydraulic fluid that has passed through the base valve 24 in this manner passes through the damping force generating valve V.

In other words, when the pressure on the flow path 26 side becomes equal to or higher than the set pressure of the damping force generation valve V, the generation valve V opens.
The hydraulic oil flows out into the oil reservoir chamber 18 via the port 28 → poppet 29 → passage 38, and when it passes through the damping force generating valve V, the desired damping force is exerted.

The set pressure of this damping force generating valve V is determined depending on the stroke of the piston 19,
The principle is as follows.

That is, when the piston 19 descends, the suspension spring 36 is compressed, and the spring force at that time acts on the detection spring b via the transmission plate 35, causing the detection spring b to bend in the direction of flattening it. Let it happen. Therefore, the transmission plate 35 descends against the detection spring b, pushing down the control rod l.

When the control rod 1 moves as described above, the control spring 30 is compressed and its spring force increases, and the set pressure of the damping force generating valve V increases accordingly.

That is, in this embodiment, the detection spring b detects the stroke of the piston by converting it into the spring force of the suspension spring 36, and
Control spring 30 according to the detected spring force
It is designed to control.

Furthermore, when the piston 19 rises, a desired damping force is generated via a known damping force generating valve provided on the piston 19, and the oil reservoir chamber
8 flows into the bottom side chamber 21 from the flow path 25 via the check valve and the base valve 24.

The second embodiment shown in FIG. 2 has a needle 3 instead of the poppet 29 of the damping force generating valve V of the first embodiment.
9, the third embodiment shown in FIG.
In place of the poppet 29, a blocking valve 40 for blocking the passage 38 is provided, and the other configurations are the same as in the first embodiment.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing the first embodiment of this invention, Figure 2 is a sectional view of the main parts of the second embodiment, and Figure 3 is a sectional view of the main part of the second embodiment.
The figure is a sectional view of the main part of the third embodiment, and FIG. 4 is a sectional view of a conventional shock absorber. 19... Piston, 18... Oil sump chamber, 20...
Rod side chamber, 21... Bottom side chamber, 36... Suspension spring, V... Damping force generating valve, b... Detection spring, l... Control rod.

Claims (1)

[Scope of utility model registration request] a damping force generating valve that causes hydraulic oil in a chamber that contracts in accordance with the compression stroke of the piston to flow out into an oil reservoir chamber;
It consists of a spring holder fitted onto the outer periphery of the cylinder, a transmission plate disposed between the spring holder and the suspension spring, and a disc spring that bends with the spring force when the suspension spring is compressed between the transmission plate and the spring holder. A damping force adjustment mechanism for a shock absorber, which includes a detection spring and a control rod that abuts the transmission plate to increase the throttle resistance of the damping force generating valve according to the amount of deflection of the detection spring.