JPS61211544A - Buffer - Google Patents

Abstract

PURPOSE:To make absorption capability for dynamic load variable by forming a fluid chamber for enclosing gas, by the first cylinder, the closed end of the first cylinder and a piston and connecting said chamber to a gas pressure source with variable supply pressure. CONSTITUTION:The end part of a rod tube 5 inserted inside of a cylinder tube 1, which is the first cylinder body, is connected to the side of a piston 2, and a dynamic load applied on the end part of the rod tube 5 is transmitted to displace the piston 2. Pressure of air in a fluid chamber A formed by the cylinder tube 1, piston 2 and a head cap 3 is set optionally by means of a compressor 13. Thus, te magnitude of damping force generated on the piston can be changed optionally.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a shock absorber, and particularly to a shock absorber that absorbs a dynamic load by utilizing the compressibility of gas.

[Background Art] For example, the following structure can be considered as a shock absorber that absorbs a dynamic body load by utilizing the elastic force generated when a gas such as air is compressed.

That is, a piston is slidably positioned in a bottomed cylindrical cylinder at a predetermined distance from the bottom of the cylinder, and the piston is a sealed cylinder consisting of the piston and the bottom of the cylinder, to which a dynamic load is applied via a piston rod. The air sealed in the fluid chamber is compressed by the movement of the piston, and the dynamic load is smoothly absorbed by the elastic force that is applied from the compressed air in a direction that prevents the movement of the piston. It is.

However, in the shock absorber having the above structure, while dynamic loads are repeatedly applied, the air sealed in the fluid chamber consisting of the cylinder bottom and the piston leaks to the outside through the sliding part of the piston and cylinder. If this occurs, characteristics such as the stroke of the piston and the ability to absorb dynamic loads will change, resulting in unstable operation.

Furthermore, performance such as the ability to absorb dynamic loads is almost uniquely determined by the diameter of the piston, the volume of the fluid chamber, and the pressure of the gas sealed in the fluid chamber during assembly.
Another drawback is that it is difficult to change specifications after manufacturing to predetermined dimensions.

In addition, the buffer that utilizes the compressibility of gas as mentioned above is
Because the movement is smooth, it is sometimes used to alleviate the impact force exerted on the worker from a load during manual work, etc.; Since there is no restraint, the piston rod moves freely around the shaft,
The inventors of the present invention have found that there are various drawbacks, such as making it difficult for the operator to hold the handle attached to the piston rod, reducing work efficiency.

[Object of the Invention] An object of the present invention is to provide a shock absorber whose operation is stable and whose dynamic load absorption capacity is variable.

[Summary of the Invention] The present invention has a structure in which a fluid chamber formed by a cylinder body, a closed end thereof, and a piston, and in which gas is sealed is connected to a gas pressure source whose supply pressure is variable. The gas pressure in the fluid chamber is stably maintained at a predetermined value to avoid performance fluctuations such as dynamic load absorption capacity caused by gas leakage from the fluid chamber, and the gas pressure in the fluid chamber can be maintained at any arbitrary value at any time. This makes it possible to adjust the dynamic load absorption capacity to a variable value.

[Embodiment 1] Figure 1 shows a cross-sectional view of a shock absorber which is an embodiment of the present invention.

A piston 2 is provided inside a cylindrical cylinder tube 1 (first cylindrical body) so as to be slidable in the axial direction.

Also, one end of the cylinder tube 1 is connected to a head cap 3 (
The closed end of the first cylindrical body is closed, and is airtightly fixed to the head cap 3 by caulking.

Furthermore, a rod cap 4 is fixed to the other end of the cylinder tube 1 by caulking, and one end of the rod tube 5 (second cylindrical body) passes through this rod cap 4 and extends in the axial direction of the cylinder tube l. It is movably inserted inside.

A rod bushing 6 is attached to a portion of the rod cap 4 through which the rod tube 5 passes, so that the rod tube 5 is smoothly guided in the axial direction.

The end of the rod tube 5 inserted into the cylinder tube 1 is connected to the side surface of the piston 2, and the rod tube 5 protrudes outside the cylinder tube 1.
The moving body acting on the end of the body is negative.

In this case, the connection between the rod tube 5 and the piston 2 is made airtight by caulking.

Further, a rod tube cap 7 is attached to the end of the rod tube 5 that projects outside the cylinder tube 1 and is subjected to a dynamic load, and is configured to be closed airtight by caulking.

A wear ring 8 and a piston packing 9 having a diameter slightly larger than that of the piston 2 are attached to the sliding portion of the piston 2, which is slidably positioned inside the cylinder tube 1, and the piston packing 9, which is slightly larger in diameter than the diameter of the piston 2. It prevents the piston 2 from wobbling in the radial direction inside the tube 1 to enable smooth displacement, and absorbs the dynamic load by being compressed by the piston 2 that is displaced by the dynamic load via the rod tube 5. , a fluid chamber A consisting of a cylinder tube 1, a piston 2, and a head camp 3.
The air inside leaks out through the sliding part, and the fluid chamber A is formed in the navel cap 3 and is connected to the speed control valve 11 (gas pressure source) through a pressure boat 10 that communicates with the fluid chamber A. It is connected to a regulator 12 (gas pressure source) and a compressor 13 (gas pressure source), so that the pressure of the gas inside the fluid chamber A can be set to any value at any time.

In this way, since the structure is such that the pressure of the air in the fluid chamber A that absorbs the dynamic load applied via the rod tube 5 and the piston 2 is maintained at an arbitrary value, the fluid chamber A
Fluctuations in performance such as the dynamic load absorption capacity and the stroke of the piston 2 due to air leakage from inside can be avoided, and stable dynamic load absorption and return operations can be performed.

Furthermore, since the air pressure in the fluid chamber A can be adjusted to any value at any time, it can be easily applied to applications such as absorbing dynamic body loads of different sizes.

Further, in the axial direction of the central part of the cylinder tube 1, a guide bar 14 having a rectangular cross section is fixed at one end to the head cap 3 and has the other end extending through the central part of the piston 2 and protrudes into the inside of the rod tube 5. is provided.

A guide bush 15 through which the guide bar 14 is inserted is attached to the penetrating portion of the guide bar 14 of the piston 2.

This guide bushing I5 has a through hole formed in the axial direction of the central part of a cylindrical member and has a rectangular cross section that is slightly larger than the cross-sectional dimension of the guide bar 14. It is designed to be guided smoothly.

The guide bush 15 is fixed to the piston 2 by a lock pin 16, so that the piston 2 and the rod tube 5 fixed to the piston 2 cannot rotate around the axis.

In this way, the built-in anti-rotation mechanism that prevents the piston 2 and rod tube 5 from floating around the axis prevents the load from acting on the worker during manual work, for example. When used for purposes such as mitigating impact forces, the piston 2 and the rod tube 5 are prevented from floating around the axis, and the operator can easily remove the jig, such as a handle, attached to the rod tube 5. It is possible to hold it stably,
Work efficiency is improved.

In addition, a guide gasket 17 is attached to the portion of the piston 2 through which the guide bar 14 passes through, with a snap ring 19 via a washer 18, so that the portion where the guide bar 14 penetrates the piston 2 is kept airtight. It is said that

In this case, when the guide bar 14 enters the sealed fluid chamber B formed inside the rod tube 5, the air in the fluid chamber B is compressed, and after the dynamic load is released. The return operation of the rod tube 5 is performed smoothly.

Furthermore, bumpers 20 and 21 made of, for example, rubber are attached to both sides of the piston 2, respectively.
Piston 2 reciprocating inside cylinder tube I
is in contact with the head cap 3 or rod cap 4 at the end of the stroke, and the small end of the stroke is
In addition, a through hole 22 is formed in the rod cap 4 in the radial direction, so that when the piston 2 is moved to the right during dynamic load absorption operation, Negative pressure is prevented from forming in the space.

Furthermore, a mounting screw hole 23 is formed in the head camp 3 so that it can be easily mounted on a predetermined device.

The operation of this embodiment will be explained below.

First, the speed control valve 1 connected to the head cap 3
1 and the pressure regulator 12 as appropriate.
Air pressure obtained from the compressor 13 is set to a predetermined value and applied to the fluid chamber A within the cylinder tube 1, and the piston 2 in an unloaded state is in a position where it is in contact with the rod cap 4.

When a dynamic load is applied to the rod tube cap 7 at the end of the rod tube 5 in the direction of pushing the rod tube 5 into the cylinder tube 1, the rod tube cap 7 is connected to the rod tube 5 and positioned inside the cylinder tube 1. The piston 2 is displaced to the right in the figure, the air in the fluid chamber A is compressed, the internal pressure rises, a braking force is generated in a direction that prevents the displacement of the piston 2, and the dynamic load is gradually absorbed. Ru.

Next, when the dynamic load is released, the piston 2 is moved to the left in the figure by the internal pressure of the fluid chamber A to the position where it comes into contact with the rod cap 4, and the rod tube 5 connected to the piston 2 is moved into the cylinder. It is projected to the outside of the tube 1 and returned to the no-load position.

In this way, the pressure of the air in the fluid chamber A that absorbs the dynamic load applied through the rod tube 5 and the piston 2 can be adjusted to an arbitrary value by being connected to the speed control valve 11, the pressure regulator 12, and the compressor 13. Because of this structure, it is possible to avoid fluctuations in performance such as the dynamic load absorption capacity and the stroke of the piston 2 due to air leakage from the fluid chamber A, and stable dynamic load absorption and return operations can be performed. be exposed.

Furthermore, by appropriately adjusting the speed control valve 11 and pressure regulator 12, it is possible to adjust the air pressure in the fluid chamber A to any value at any time, making it suitable for applications that absorb dynamic loads of different sizes. Easy to use.

Further, when the rod tube 5 is moved in the direction of being pushed into the cylinder tube 1 in the dynamic load absorbing operation, the guide bar 14 is relatively entered into the fluid chamber B inside the rod tube 5, and the fluid is Since the internal pressure of the chamber B has been increased, when the dynamic body load is released, the return operation of the rod tube 5 is performed more smoothly in conjunction with the internal pressure of the fluid chamber A.

Further, the piston 2 has a guide bar 1 having a rectangular cross section.
4 and guided in the axial direction of the cylinder tube 1, the piston 2 and the rod tube 5 are prevented from floating around the axis. When the piston 2 and the rod tube 5 are used to alleviate the impact force exerted on the worker from a load in manual work, etc., it is possible to avoid the piston 2 and the rod tube 5 from being in a floating state around the axis, and the rod tube 5 It becomes possible for the worker to stably hold the attached jig, such as a handle, and work efficiency is improved.

Note that the present invention is not limited to the above-mentioned embodiments; for example, instead of the speed control valve 11, a two-port solenoid valve having a function of simply connecting or blocking a flow path that communicates the compressor 13 and the fluid chamber A may be used. It is also possible to provide

Further, the cross-sectional shape of the guide bar may be a square or a rectangle, or any other non-perfect circular shape that can prevent rotation, such as another polygon or an ellipse.

Note that it is also possible to provide a rotation prevention mechanism in which the outer circumferential surface of the rod tube 5 and the inner circumferential surface of the rod bush 6 have a non-perfect circular cross-sectional shape that can prevent rotation.

[Effect (1): The structure is formed by the closed end of the first cylindrical body and a piston that is displaced by the action of a dynamic load, and the gas is sealed in the fluid chamber, so there is no possibility of leakage of the gas sealed in the fluid chamber. Changes in performance such as the braking force generated in the piston and the stroke of the piston due to this are prevented, and stable dynamic load absorption operation can be obtained.

(2) As a result of (1) above, it is possible to set the gas pressure in the fluid chamber to a desired value, so the magnitude of the braking force generated on the piston can be arbitrarily changed, and the A shock absorber with variable load absorption capacity is obtained.

(3) A rectangular cross section that axially passes through a piston whose one end is fixed to the closed end of the first cylinder and whose other end is located inside the first cylinder and projects into the inside of the second cylinder. By providing a guide bar having a non-perfect circular cross-sectional shape capable of preventing rotation, the piston is prevented from floating around the axis.

(4) As a result of (3) above, when the piston and the second cylindrical body connected to the piston are This allows the operator to stably hold a jig such as a handle attached to the second cylindrical body, and improves work efficiency.

(5) As a result of (3) above, the gas pressure inside the second cylinder is increased by the guide bar that enters the second cylinder during the dynamic load absorption operation, so that the dynamic load is released. The return operation of the second cylindrical body after the second cylindrical body is carried out more smoothly.

[Brief explanation of drawings]

The figure is a sectional view of a shock absorber that is an embodiment of the present invention. 1... Cylinder tube (first cylindrical body), 2...
・Piston, 3... Head cap (closed end of the first cylindrical body), 4... Rod cap, 5... Rod tube (second cylindrical body), 6... Rod bush, 7...・Rod tube cap, 8... Wear ring, 9... Piston seal, 10... Pressure boat, 1... Speed control valve (gas pressure source), 12... Pressure regulator (gas pressure source), 13...Compressor (gas pressure source), 14...
Guide bar, 15...Guide bush, 16...Lock pin, 17...Guide bushing, 18...Washer, 19...Snap ring, 20.21...Bumper, 22... Through hole, 23... Mounting hole.

Claims (3)

[Claims] (1) a first cylindrical body with one end closed; a piston slidably positioned within the first cylindrical body; and a piston that is movable axially into the cylinder from the open end of the first cylindrical body. and a second cylinder whose ends protruding to the outside of the first cylinder and the ends connected to the piston are closed, respectively, the first cylinder and the first cylinder are closed. A shock absorber characterized in that a fluid chamber formed by the closed end of the cylindrical body and the piston and filled with gas is connected to a gas pressure source whose supply pressure is variable. (2) A non-piston whose one end is fixed to the closed end of the first cylinder and whose other end protrudes into the second cylinder through a piston that is located inside the first cylinder in the axial direction. 2. The shock absorber according to claim 1, further comprising a built-in anti-rotation mechanism having a guide bar having a circular cross section. (3) The shock absorber according to claim 1, wherein the gas is air.