JPS6030499Y2 - Double-tube shock absorber that separates oil and gas - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a dual-tube shock absorber that separates oil and gas.

In general, in a dual-tube type gas-filled shock absorber that has an outer razor per tube that forms a gas chamber and an inner pressure tube that forms an oil chamber, the oil chamber and gas chamber are generally separated. If not, gas will enter through the oil hole in the upper bearing, and the seal will become a gas shaft seal instead of an oil shaft seal, so gas will easily escape to the outside, resulting in disturbances in the damping force waveform.

Additionally, as the piston rod moves up and down, gas enters the bearing guide, mixes with oil in the cylinder that generates damping force, and causes aeration, causing disturbances in the damping force waveform and play in operation. It can also cause abnormal noise.

For this reason, as a method for solving this problem, an oil damper is known, as disclosed in, for example, Japanese Utility Model Publication No. 48-25495.

In this type, a lip is provided on the seal portion to allow the flow of oil and gas from the cylinder to the gas chamber, while blocking the flow of gas from the gas chamber to the cylinder.

However, with this structure, unexpected pressure is applied to the main lip of the seal to confine the jet flowing from the guide of the bearing part in a local space, and high-temperature hydraulic oil generated from thermal energy due to the generation of damping force is unavoidable. As a result, the product was poured onto the lip while it was still warm, which inevitably resulted in a decrease in the durability of the seal itself.

In addition, the piston rod always bends during operation, generating a twisting moment, and the main lip of the seal needs to follow this movement, but this movement is restricted due to the lip provided on the seal, preventing twisting, etc. This is something that can be seen occurring.

Therefore, in order to solve these conventional drawbacks, we installed a flexible check valve independent of the seal in the middle of the passage connecting the cylinder and gas chamber in order to separate the oil and gas, improve the damping force waveform, and prevent noise. The applicant has developed a dual-tube shock absorber that takes into account the durability of the seal and has applied for a patent.

However, in this case, the check valve made of an elastic material such as rubber is fixed to the bent end of the packing plate, so the operating heat of the shock absorber □ is directly transmitted to the check valve, and the shock absorber is repeatedly operated. The seal behaves due to the amplitude movement of the piston rod due to the vibration, and the high frequency or chatter vibration caused by this behavior is directly propagated to the check valve, resulting in the check valve itself cracking or faltering, causing the check seal function to deteriorate. Not only does this lead to loss of followability, but since the packing plate is bent, the contact area between the packing plate and the packing decreases, increasing the load per unit area, which adversely affects the durability of the packing, and furthermore, the bearing There was a problem in that the fluid ejected from between the piston rod and the piston rod directly hit the packing, significantly reducing the performance of the packing itself.

Therefore, an object of the present invention is to bring the packing plate into contact with the bottom surface of the packing over the entire lower end without bending it, and furthermore, to make the packing plate contact the bottom surface of the packing over the entire lower end without bending, and further, to provide a support member that is located between the bottom surface of the packing plate and the bearing and is fixed to the support member that abuts the packing plate. By interposing a check valve with a flexible check seal lip, the seal and the check valve are made independent by the seal plate, and the behavior of the seal is not propagated to the seal lip of the check valve. Therefore, it is an object of the present invention to provide a shock absorber which does not cause cracks or sag in the check valve and has good durability and followability of the check valve as well as durability of the packing itself.

The embodiment of the present invention will be explained below with reference to the drawings. First, in the shock absorber, a bearing 2 is fixed to the upper end of a cylinder 1, and a piston rod 3 is slidably inserted into the center of the bearing 2. has oil chamber 4
is divided.

A cover 5 is fixed above the bearing 2.
A piston rod 3 passes through the center of the piston rod 3, and a gasket 6 is disposed inside the piston rod 3. An inner lip 7 of the gasket 6 slides on the outer circumference of the piston rod 3 to prevent oil leakage and leakage from the outside of the cover 5. Each prevents dust from entering.

Upper end of bearing 2 and seal plate 8 of seal 6
There is a flexible check seal lip part 1 on the support member 9 between the parts.
A check valve 10 is provided, in which the check valve 10 is pressed against the packing 6 side via the support member 9 by a spring S interposed between the check valve 10 and the bearing 2. An oil retaining chamber 11 and a chamber 12 are defined between the oil seal 6 and the bearing 2 by the oil seal 6, the piston rod 3, and the bearing 2.

The check valve 10 is formed by baking a flexible member such as rubber onto the lower inner periphery of a support member 9 serving as a reinforcing member to form a flexible seal lip portion 13 having a check seal function.

Further, an outer tube 14 concentric with the cylinder 1 is fixed to the cover 5, and a gas chamber 15 is defined within the outer tube 14. By isolating the gas chamber 15 and the oil chamber 4, gas and oil can be separated. It is now possible to do so.

However, the lower part of the gas chamber 15 is filled with oil.

On the other hand, a through hole 16 is bored in the bearing 2, and this through hole 16
The oil storage chamber 11 and the chamber 12 are made to communicate with the gas chamber 15.

In this case, since the check valve 10 is disposed in contact with the packing 6, the gas from the gas chamber 15 acts in the direction of closing the seal lip portion 13 of the check valve 10, and therefore flows out into the oil storage chamber 11. However, when the internal pressure of the oil storage chamber 11 increases, the seal lip portion 13 of the check valve 10 is bent, and the oil in the oil storage chamber 11 flows out into the gas chamber 15 through the through hole 16.
Furthermore, the oil is configured to flow down to the oil level below the gas chamber 15.

That is, in the shock absorber of the present invention, oil in the oil chamber due to the sliding movement of the piston rod 3 leaks into the oil storage chamber 11 from the gap between the bearing 2 and the screw 1, 13, and this leaked oil is temporarily stored. However, since the seal lip portion 13 of the check valve 10 is flexible and comes into contact between the lower surface of the gasket 6 and the bearing 2 under a minute set load, this oil is stored in the oil storage chamber 11. When the oil chamber 11 is filled with oil and the internal pressure rises above the set load of the seal lip portion 13 of the check valve 10, the seal lip portion 13 of the check valve 10 bends outward and opens, opening the oil storage chamber. 11 oil in chamber 12,
It is made to flow into the gas chamber 15 through the through hole 16.

At this time, since the check valve 10 has a support member 9 built inside, the flexible check seal lip portion 13 of the check valve 10 is always reinforced and supported with a constant strength, and the support member 9 of the check valve 10 9 is piston rod 3
Because they are separated by the packing plate 8 interposed between the oil seal 6 and the oil seal 6 that comes into contact with the piston rod, the behavioral force of the packing 6 due to high frequency or chatter vibration of the piston rod 3, the packing plate 8 and the check valve 10 are Since this movement is absorbed by the deviation that occurs between the contact surfaces of the check valve 10, the seal lip portion 13 does not move to follow this behavior, and the durability of the check valve 10 itself is significantly improved, making it possible to withstand long-term use. Not only piston rod 3
It is also possible to improve the followability of the packing 6 to the inclination of.

In the shock absorber according to the embodiment described above, the packing 6 and the check valve 10 are independent of each other through the packing plate 8, so that even if bending or twisting moment occurs in the packing 6, the check valve 10 As described above, since the seal lip 13 of the check valve 10 does not follow the movement of the seal 6, the seal lip 13 of the check valve 10 does not become distorted, and the jet flow to the lip 7 of the seal 6 is not confined within the same room, reducing the jet pressure. becomes possible.

Furthermore, the flexible sealing lip portion 13 of the check valve 10
The opening pressure can be controlled freely by selecting the material, such as rubber hardness, regardless of the seal.
It is possible to optimally control the pressure applied to the seal by synchronizing the decrease in the viscosity of the hydraulic oil due to high temperatures, the increase in the amount of ejection from the gap between the bearing and the piston rod, and the decrease in rubber hardness due to high temperatures.

Furthermore, by removing the check valve, it is possible to easily configure the shock absorber as a standard shock absorber that is not a gas-filled type.

Furthermore, since the jet flow toward the lip of the seal is stored in the oil storage chamber, which has a large space, a cooling effect can be expected in terms of temperature, and the jet pressure can be reduced.

[Brief explanation of the drawing]

The figure is a partially cutaway vertical sectional view of a shock absorber according to an embodiment of the present invention. 1...Cylinder, 2...Bearing,
3... Piston rod, 6... Packingskin, 8... Packing plate, 9...
Support member, 10... Check valve, 13...
...Check seal lip part, 15...Gas chamber, S...Spring.

Claims (1)

[Scope of utility model registration request] In a shock absorber, a bearing for guiding a piston rod and a packing for preventing external leakage of hydraulic oil are interposed in the upper part of the cylinder, and an outer tube for partitioning a gas chamber is arranged on the outside of the cylinder, A packing plate is attached to the lower end of the packing, and a check valve having a flexible check seal lip portion whose base end is fixed to a support member that abuts the packing plate is interposed between the packing plate and the upper end of the bearing. A double-tube type that separates oil and gas, in which the seal lip of the check valve is brought into contact with the bearing, and a spring is disposed on the upper surface of the bearing to press the support member toward the packing plate. shock absorber.