JPS6118058B2 - - 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 tube forming the gas chamber and an inner cylinder forming the oil chamber, if the oil chamber and gas chamber are not separated, the upper Gas enters through the oil holes in the bearing, and the seal becomes a gas shaft seal instead of an oil shaft seal, so the gas tends to escape to the outside, which tends to cause disturbances in the damping force waveform.
Additionally, as the piston rod moves up and down, gas infiltrates into the cylinder from the guide of the bearing section, and the oil and gas mix in the cylinder, creating an air ratio that disrupts the damping force waveform and causes play in the operation, causing abnormal noise. It can also be the cause of For this reason, a hydraulic shock absorber as disclosed in, for example, Japanese Utility Model Publication No. 48-25495 is known as a method for solving this problem. This one has a lip that acts as a check valve integrated into the seal part, allowing oil to flow from the cylinder to the gas chamber. It is formed to cut off the flow of gas from the gas chamber to the cylinder. However, in such a hydraulic shock absorber, the piston rod, which is slidably installed inside the shock absorber, is constantly bent during operation, generating a twisting moment, and the lip provided integrally with the sealing member must make a corresponding movement. However, since the lip is provided integrally with the sealing member, the movement is restrained by the lip.
As a result, twisting and the like occur, which not only deteriorates followability but also adversely affects durability and sealing performance. Furthermore, since the sealing member and the lip are integral, the lip and the sealing member must be made of the same material, and the position of the lip is determined by the relationship between the piston rod and the sealing member, and the position cannot be adjusted. This has caused various problems such as insufficient check functions.

Therefore, the purpose of the present invention is to solve these conventional drawbacks by providing a double cylinder that separates oil and gas, which significantly improves the durability and followability of the check valve lip, and improves the check function regarding gas sealing properties. The purpose of the present invention is to provide a type shock absorber. In order to achieve this object, the present invention includes a cylinder in which an oil chamber is formed, an outer tube disposed on the outer periphery of the cylinder, a gas chamber formed above between these cylinders and the outer tube, and a cylinder in which an oil chamber is formed. a piston rod that is movably provided within the cylinder and has one end protruding from the cylinder to the outside via a bearing and a sealing member that seals the inside and outside of the cylinder; a through hole that penetrates the bearing and opens into the gas chamber; and the gas chamber. In the shock absorber, the check valve mechanism is provided between the oil chamber in the cylinder and a check valve mechanism that allows oil to flow only from the oil chamber in the cylinder to the gas chamber side, and the check valve mechanism is connected to the seal member. The check valve mechanism is constructed of a separate member and is disposed between the bearing and the seal member without contacting the piston rod, while the proximal end side of the check valve mechanism is connected to the lower part of the seal member via a spring supported on the upper surface of the bearing. Further, the distal end of the check valve mechanism is brought into contact with a valve seat formed in the bearing so as to be able to be moved into and out of the valve seat, and is also located below the upper opening end position of the through hole. It is something.

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

In the figure, in the shock absorber, a bearing 25 is fixed to the upper end of a cylinder 1, a piston rod 3 is movably inserted into the center of the bearing 25, and an oil chamber 4 is defined within the cylinder 1.

Above the bearing 25 is a packing cover 26.
An outer tube 10 concentric with the cylinder 1 is fixed to this cover 26, and a gas chamber 1 is provided above between the outer tube 10 and the cylinder.
1 is partitioned, and by isolating the gas chamber 11 and the oil chamber 4, gas and oil can be separated. However, the lower part of the gas chamber 11 is filled with oil.

A packing 27 as a seal member is disposed within the cover 26, the piston rod 3 movably passes through the bearing 25 and the packing 27, and a plurality of lips 28 provided on the inner periphery of the packing 27 are in sliding contact with the piston rod 3. Prevents oil leakage and dust infiltration. An oil chamber 29 of an arbitrary size is formed between the packing 27 and the bearing 25 to temporarily store oil flowing out from the gap 13 between the bearing 25 and the piston rod 3. A through hole 33 is bored through the bearing 25 vertically, and this through hole 33 opens into a chamber 34 in the cover 26 and the gas chamber 11 to allow communication between the two. Oil room 2
A check valve mechanism V which is in a non-contact state with the piston rod 3 is disposed at the mouth end of the piston rod 9, and the proximal end side of the check valve mechanism V contacts the lower part of the packing 27, and the check valve 30, which is the distal end, is mounted on a bearing. 25
The valve seat 36 is brought into contact with the valve seat 36 so as to be openable and closable. That is,
Attach the thick base end of the check valve mechanism V to the gasket 27.
One end of the bearing 25 is accommodated in a housing recess 35 formed at the lower part of the bearing 25 through the plate 31.
It is pressed and held by a spring 32 supported on the upper surface, while the check valve 30, which is the tip, is applied to the bearing 2 by a slight set load due to its flexibility.
5. The valve seat 36, which is the outer peripheral tapered surface of a truncated conical protrusion 37 protruding from the upper part, is in contact with the valve seat 36 so as to be separable from the valve seat 36. Moreover, the check valve mechanism V has 30 check valves.
The tip of the through hole 33 is located below the level of the upper mouth end position 1 of the through hole 33.

Therefore, the oil overflowing from the oil chamber 29 is drained into the annular recess 34' located below the upper opening end position l of the through hole 33.
This means that the check valve 30 is in contact with this stored oil. Therefore, gas from the gas chamber 11 passes through the check valve 3.
Even if the lubricant acts on the lubricant at zero, it will not dry, and so-called dry lubrication can be prevented.

On the other hand, as the piston rod 3 slides, oil in the oil chamber 4 leaks from the gap 13 between the bearing 25 and the piston rod 3 into the oil chamber 29, and this leaked oil is temporarily stored in the oil chamber 29, but When the internal pressure rises due to the oil filling the check valve 29, this oil pushes open the check valve 30, accumulates in the annular recess 34', and then flows out into the gas chamber 11 through the through hole 33. On the other hand, the gas pressure in the gas chamber 11 acts on the check valve 30 through the through hole 33 and the chamber 34 to force it in the closing direction, thereby cutting off the flow of gas from the gas chamber 11 toward the oil chamber 4 side.

According to the present invention, the following effects are achieved. In other words, since the check valve mechanism is made up of a separate member and is independent of the seal member, even if a bending or twisting moment occurs in the seal member, the check valve mechanism will not follow the movement of the seal member. The check valve at the tip does not need to be twisted. The material of the check valve that is most suitable for performing the check function can be selected regardless of the material of the seal member, and the opening pressure can be freely controlled accordingly. The pressure applied to the seal can be optimally controlled by adjusting the increase in the amount of ejection from the gap with the piston rod and the decrease in rubber hardness due to high temperatures to changes in opening pressure. Furthermore, by removing the check valve mechanism, it is possible to easily configure it as a standard shock absorber that is not a gas-filled type. Since the check valve mechanism is in a non-contact state with the piston rod, it is not affected by the vibrations of the piston rod and can improve durability. The check valve can be assembled independently of the piston rod, making assembly easy.
Since the tip of the check valve mechanism is located below the upper opening of the through hole, this tip comes into contact with the oil that has accumulated below the upper opening of the through hole, causing dry lubrication. The durability of the check valve mechanism is improved. Since there is nothing to prevent the check valve from deflecting outward, the response when opening is good.

[Brief explanation of the drawing]

The accompanying drawing is a partially cutaway vertical side view of a shock absorber according to an embodiment of the present invention. 1... Cylinder, 2... Bearing, 3... Piston rod, 10... Outer tube, 11
... Gas chamber, 27 ... Seal member, 28 ... Lip, 29 ... Oil chamber, 30 ... Check valve, 32 ...
... Spring, 35 ... Accommodation recess, 36 ... Valve seat, V ... Check valve mechanism, l ... Upper mouth end position of through hole.

Claims (1)

[Claims] 1. A cylinder forming an oil chamber, an outer tube provided on the outer periphery of the cylinder, a gas chamber formed above between these cylinders and the outer tube, and a cylinder provided movably within the cylinder and having one end. The piston rod protrudes from the cylinder to the outside through a bearing and a sealing member that seals the inside and outside of the cylinder, and the piston rod is located between the through hole that penetrates the bearing and opens into the gas chamber, and the gas chamber and the oil chamber in the cylinder. In a shock absorber equipped with a check valve mechanism that allows oil to flow only from the oil chamber to the gas chamber side in the cylinder, the check valve mechanism is constructed of a member separate from the seal member and is not connected to the piston rod. While the check valve mechanism is disposed between the bearing and the seal member in a state of contact, the proximal end side of the check valve mechanism is pressed against the lower part of the seal member via a spring supported on the upper surface of the bearing, and the distal end of the check valve mechanism is A double-tube type shock that separates oil and gas, characterized in that the valve seat formed in the bearing is in contact with the valve seat so that it can be moved into and out of the valve seat, and is located below the upper opening end position of the through hole. absorber.