JPH0579528A - Oil damper - Google Patents

Abstract

PURPOSE:To maintain damping characteristic at a constant level by means of a simple structure even if viscosity of working oil is varied in response to temperature. CONSTITUTION:A fluid chamber 30 which moves synchronously with a piston 3 which partitions the inside of a cylinder 2 into a first chamber 5 and a second chamber 6 is provided. A regulation member 25 which is actuatel according to a volumetric variation of the temperature of fluid filled in the fluid chamber 30 is provided, and an opening of an orifice 23 which connects the first chamber 5 to the second chamber 6 is varied according to the operation of the regulation member 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil damper, and is particularly suitable for being used in an environment where the temperature changes drastically.

[0002]

2. Description of the Related Art A conventional oil damper 101 shown in FIG.
The first chamber 104 and the second chamber 105 inside the cylinder 103 separated by the piston 102 communicate with each other through an orifice 106 provided in the piston 102.
A spring 10 is provided between the piston 102 and the cylinder 103.
7, the spring 1 expands and contracts, and the piston 1
02 moves back and forth. When the piston 102 moves, the hydraulic oil filled in the cylinder 103 causes the orifice 1
The vibration of the spring 107 is attenuated because it is narrowed at 06.

[0003]

When the conventional oil damper is used in an environment where the temperature changes remarkably, such as in outer space, the viscosity of the hydraulic oil changes, and the damping characteristic changes greatly.

Therefore, it is conceivable that the orifice provided in the piston is an electric variable orifice and the opening degree of the orifice is changed and adjusted according to the temperature change. However, if the electric variable orifice is used as the orifice, the structure becomes complicated and a control device is also required, resulting in a large and expensive one.

In view of the above-mentioned prior art, it is an object of the present invention to provide an oil damper which has a simple structure and is capable of adjusting the opening of the orifice according to the temperature change.

[0006]

The characteristic feature of the oil damper according to the present invention is that the first chamber and the second chamber inside the cylinder separated by the piston communicate with each other through the orifice provided in the piston. In the oil damper, a fluid chamber that moves along with the piston is provided, and an adjusting member that operates according to a volume change due to the heat of the fluid filled in the fluid chamber is provided, and the opening of the orifice is performed by the operation of the adjusting member. The point is that the degree can be changed.

[0007]

According to the structure of the present invention, when the adjusting member is activated by thermal expansion or thermal contraction of the fluid filled in the fluid chamber, the opening of the orifice provided in the piston changes. As a result, even if the viscosity of the oil filled in the cylinder changes due to the temperature change, the opening of the orifice changes due to the operation of the adjusting member according to the temperature change, so that the damping characteristic can be prevented from changing. ..

[0008]

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

The oil damper 1 shown in FIG. 1 is used, for example, for shock absorption when an artificial satellite is docked in outer space, and is mainly composed of a cylinder 2, a piston 3 and a spring 10. The piston 3 is inserted into the cylinder 2 so as to be movable in the left-right direction in the drawing. A seal ring 4 contacting the inner circumference of the cylinder 2 on the outer circumference of the piston 3.
Is attached, whereby the interior of the cylinder 2 is separated by the piston 3 into a first chamber 5 and a second chamber 6. Further, seal rings 7 and 8 which are in contact with the outer circumference of the piston 3 are attached to the inner circumferences of both ends of the cylinder 2. In addition,
Spaces 15 and 16 surrounded by the outer circumference of the piston 3 protruding from both ends of the cylinder 2, the peripheral walls 11 and 12 integrally formed with the cylinder 2, and the bellows 13 and 14 are formed. By filling the fluid with the atmospheric pressure, the seal rings 7 and 8 are protected when the oil damper 1 is used in outer space.

A flange 9 is formed at the left end of the piston 3 in the drawing, and a compression coil spring 10 is interposed between the flange 9 and the left end of the cylinder 2 in the drawing. The elastic force of the spring 10 causes the piston 3 to move in the drawing. Pressed to the left.

The piston 3 is hollow and is separated by a partition wall 17 into a third chamber 18 on the right side in the drawing and a fourth chamber 19 on the left side in the drawing. The third chamber and the second chamber communicate with each other through a through hole 35 formed in the piston 3. The partition 17
A cylindrical peripheral wall 20 protruding toward the third chamber 18 is integrally formed therewith, and a cylindrical guide member 21 is screwed inside the peripheral wall 20. A tubular valve member 22 is inserted into the guide member 21 so as to be movable in the left-right direction in the drawing. The internal space of the valve member 22 communicates with the first chamber 5 through a through hole 34 formed in the partition wall 17. The valve member 2
An orifice 23 is formed at the bottom of No. 2 and a plurality of through holes 22a are formed at the periphery. In addition, the valve member 22 is an inward flange 21a formed at the right end of the guide member 21 in the figure.
A spring 24 is provided for pressing against. This valve member 2
When 2 is pressed against the inward flange 21a, the space between the through hole 22a of the valve member 22 and the third chamber 18 is closed, and the valve member 22 resists the elastic force of the spring 24 to the left in the drawing. In the state of moving to the one side, the space between the through hole 22a and the third chamber 18 is opened.

A rod (adjustment member) 25 is inserted into the partition wall 17, a tip portion 25a of the rod 25 is tapered toward the right in the drawing, and the tip portion 25a is arranged inside the orifice 23. There is. As a result, when the rod 25 moves to the right in the drawing, the opening of the orifice 23 decreases, and when the rod 25 moves to the left in the drawing, the opening of the orifice 23 increases.

Flanges 26 and 27 are formed at the left end of the rod 25 in the figure and an axially intermediate portion, and an elastically deformable plate 28 is integrated with the axially intermediate flange 27. Is attached to. A bellows 29 is attached between the plate 28 and the flange 26. As a result, the fourth chamber 19 is
It is divided into a fluid chamber 30 on the left side of the bellows 29, an internal space 31 of the bellows 29, and a space 32 on the right side of the plate 28. Liquid or gas having a large coefficient of thermal expansion is enclosed in the fluid chamber 30, and the inner space 32 of the bellows 29 is filled.
Atmospheric pressure gas is enclosed in. The right space 32 of the plate 28 communicates with the first chamber 5 through a communication hole 33 formed in the piston 3.

By supplying the working oil to the inside of the cylinder 2, the first chamber 5, the second chamber 6, the third chamber 18 and the space 32 are filled with the working oil.

According to the oil damper 1 having the above structure, when the piston 3 receives an impact and moves to the right in the figure, the impact is absorbed by the elastic deformation of the spring 10. This movement of the piston 3 to the right in the figure causes the hydraulic oil in the second chamber 6 to move to the third position.
The pressure of the hydraulic oil flowing into the chamber 18 acts on the valve member 22. This causes the valve member 22 to move to the spring 24.
Since the third chamber 18 and the opening 22a of the valve member 22 communicate with each other by moving to the left in the figure against the elastic force of the hydraulic fluid, the hydraulic oil communicates not only through the orifice 23 but also through the opening 24. From the hole 34 to the first chamber 5. Therefore, even if the flow of the hydraulic oil is throttled in the orifice 23, the impact absorption due to the elastic deformation of the spring 10 is not hindered.

Next, the restoring force of the spring 10 causes the piston 3 to move.
Is moved to the left in the figure, the hydraulic oil in the first chamber 5 is transferred to the communication hole 3
4 to the inside of the valve member 22. Thereby, the valve member 2
2 is a guide member 2 due to the elastic force of the spring 24 and the pressure of the hydraulic oil.
1 is pressed against the inward flange 21a and the through hole 22a
And the third chamber 18 are closed. Therefore, the hydraulic oil flowing from the first chamber 5 to the second chamber 6 via the third chamber 18 is throttled at the orifice 23, and a force for preventing the movement of the spring 10 of the piston 3 due to the restoring force is generated. Vibration is dampened.

When the ambient temperature of the oil damper 1 changes,
Since the volume of the fluid filled in the fluid chamber 30 changes according to the coefficient of thermal expansion, the bellows 29 expands and contracts and the rod 25 moves in the left-right direction in FIG. Even if the viscosity of the hydraulic oil inside the cylinder 2 changes according to the temperature due to the change in the opening degree of the orifice 23 based on the movement of the rod 25,
The damping characteristics do not change. That is, when the temperature rises and the viscosity of the hydraulic oil decreases, the thermal expansion of the fluid in the fluid chamber 30 moves the rod 25 to the right in the figure, the opening of the orifice 23 decreases, and the temperature decreases. When the viscosity of the fluid becomes high, the rod 25 moves leftward in the drawing due to thermal contraction of the fluid in the fluid chamber 30, and the opening degree of the orifice 23 increases.

The present invention is not limited to the above embodiment. For example, although the present invention is applied to the oil damper used in outer space in the above embodiment, the present invention can be applied to any oil damper used in an environment where the temperature changes significantly. Further, although the present invention is applied to the oil damper in which the valve member of the check valve is provided with the orifice in the above-described embodiment, the present invention can also be applied to an oil damper having no check valve function.

[0019]

According to the oil damper of the present invention, the opening of the orifice provided in the piston is adjusted according to the temperature change, so that the viscosity of the working oil inside the cylinder changes according to the temperature change. The damping characteristic can be kept constant, and the opening degree of the orifice is adjusted according to the volume change due to the heat of the fluid filled in the fluid chamber, so that the structure can be simplified.

[Brief description of drawings]

FIG. 1 is a sectional view of an oil damper according to an embodiment of the present invention.

FIG. 2 is a sectional view of an oil damper according to a conventional example.

[Explanation of symbols]

 1 Oil Damper 2 Cylinder 3 Piston 5 1st Chamber 6 2nd Chamber 23 Orifice 25 Rod (Adjustment Member) 30 Fluid Chamber

Claims (1)

[Claims] 1. An oil damper in which a first chamber and a second chamber inside a cylinder separated by a piston communicate with each other through an orifice provided in the piston, and a fluid chamber which moves along with the piston is provided. An oil damper provided with an adjusting member that operates according to a volume change due to heat of a fluid filled in the fluid chamber, and the opening degree of the orifice can be changed by the operation of the adjusting member.