JPH0726593Y2 - Shock absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a shock absorber that absorbs kinetic energy of a load.

[Conventional technology]

Conventionally, a shock absorber for absorbing kinetic energy is often used in a stop device for stopping a kinetic load such as a pallet conveyed on a conveyor at a fixed position.

A conventional shock absorber absorbs the kinetic energy of the load as the piston connected to the piston rod moves in the pressure chamber, and after the load is removed, the piston and piston rod are automatically moved by a return spring. It is configured to return to the original position.

[Problems to be solved by the device]

However, if the load is only an inertial load, or if the position holding force of the load due to friction etc. is weak, the load is pushed back by the return spring together with the piston and piston rod in the direction of the original position after the stop, and therefore the load However, there is a problem that the load (for example, pallet) cannot be positioned because the stop position of is shifted.

On the other hand, without using a return spring as a return means, the return is made by the pressure of a fluid such as air, and the electromagnetic switching valve is used to control the supply timing of the pressure fluid for the return. Zorba is proposed.

However, this complicates the structure, and when the shock absorber is a hydraulic type and an oil tank for converting return air pressure into hydraulic pressure is used, a large space for the oil tank is required. Need
Further, there is a problem that compressed air easily mixes with oil.

In view of the above problems, the present invention has an object to provide a shock absorber having a simple structure that prevents the load from being pushed back by a return spring or the like after stopping, and prevents the position of the load from shifting after stopping. There is.

[Means for Solving the Problems]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention allows a piston connected to a piston rod to move in a pressure chamber toward a stroke end to absorb an impact and to return the piston and the piston rod by a returning means. In the shock absorber configured in
The cover on the stroke end side of the piston is provided with a permanent magnet for attracting the piston, and the permanent magnet is between an actuator attracting position and an attraction releasing position by an actuator. , Is configured to be movable in a direction perpendicular to the axis of the piston.

[Action]

By pushing the load against the tip of the piston rod,
The piston moves in the pressure chamber, thereby exerting a cushioning action, and the piston reaches the stroke end and stops.

At the stroke end of the piston, the piston is attracted to the permanent magnet, the axial movement of the piston is restricted, and the position of the piston is maintained.

When the permanent magnet is moved by the actuator, the attractive force between the permanent magnet and the piston is reduced, and the restriction on the axial movement of the piston is released.

When the load is removed, the piston and piston rod are returned by the return means.

〔Example〕

FIG. 2 is a sectional front view of the shock absorber 1 according to the present invention.

The shock absorber 1 includes a main body housing 4, covers 6 and 7 for closing both ends of the main body housing 4, a pressure tube 5 having a plurality of return holes 10, 10 ... And throttle holes 11, 11 ... Piston 8 sliding on the inner peripheral surface of tube 5,
A compression spring 2a for urging the piston 8 to the outlet side opposite to the stroke end, and an accumulator 9 provided between the pressure tube 5 and the main body housing 4 for storing oil flowing out from the pressure tube 5. , A piston rod 2 integrally connected to the piston 8, a cushion pad 3 attached to the tip of the piston rod 2, and an end made of a non-magnetic material such as stainless steel provided between the pressure tube 5 and the cover 6. It is composed of a plate 6b, a lock device 14 provided on the cover 6 on the stroke end side, and the like.

The piston 8 is provided with a check valve 13a made of hard balls 13 or the like, and when the piston 8 returns, oil flows through the check valve 13a from the piston chamber 5b into the pressure chamber 5a at high speed. The piston 8 is made of a magnetic material such as iron, and its entrance end is an attraction portion 8a that magnetically attracts a permanent magnet 23 described later.

Referring to FIG. 1, the lock device 14 includes a suction member 21 slidably provided in a hole 6a formed in a cover 6 made of a non-magnetic material, and a suction member 21 which serves as an axial center of a piston 8. It is composed of a single-acting pneumatic cylinder 22 for moving in a right angle direction.

The attraction member 21 includes a permanent magnet 23 and a holding member 24 for holding the permanent magnet 23 and connecting the permanent magnet 23 to the piston rod 25 of the pneumatic cylinder 22.

The pneumatic cylinder 22 has a cylinder body 22a, which is provided with a screw on the outer peripheral surface and is screwed into the cover 6, and a piston rod 2
It is composed of a piston 26 integrally connected with 5, a compression spring 27 for urging the piston 26 toward the entrance side, and the like. 28 is a port.

Further, the hole 6a of the cover 6 communicates with the atmosphere via the hole 31 and the air breather 32.

Next, the operation of the shock absorber 1 configured as described above will be described.

First, in the state shown in FIG. 2, when the cushion pad 3 collides with the load from the direction of arrow B, the piston 8 moves in the pressure tube 5 toward the stroke end, and accordingly, the piston 8 moves through the throttle hole 11. The back pressure of the oil flowing out from the throttle hole 11 is generated in the pressure chamber 5a to generate a drag force on the piston 8, which absorbs the kinetic energy of the load and exerts a buffering action, so that the piston 8 is closed. It reaches the stroke end and stops (state of FIG. 1).

At the stroke end of the piston 8, the suction portion 8a of the piston 8
Is attracted by the permanent magnet 23, and the movement of the piston 8 in the axial direction is restricted. Therefore, even if the position holding force of the load is weak, the position of the stroke end of the piston 8 is held without being pushed back by the compression spring 2a.

When compressed air is supplied from the port 28 of the pneumatic cylinder 22, the piston 26 and the piston rod 25 move to the outlet side against the compression spring 27, whereby the suction member 21 moves upward in FIG. The attraction force between 8a and the permanent magnet 23 is greatly reduced. Therefore, the restriction on the axial movement of the piston 8 is released. When the load is removed in this state, the piston 8 and the piston rod 2 return to their original positions by the compression spring 2a.

When the supply of compressed air to the port 28 is stopped, the piston rod 25 and the piston 26 are returned to their original positions by the compression spring 27.

According to the above-described embodiment, the attraction portion 8a and the permanent magnet 23 are attracted to each other at the stroke end of the piston 8, and the axial movement of the piston 8 is regulated and held at that position, so that after the load is stopped. It is not pushed back by the compression spring 2a, and the position after the load is stopped does not shift.

Further, when the movement restriction of the piston 8 is released, the suction member 21 is moved by the pneumatic cylinder 22 in the direction perpendicular to the axial center of the piston 8, so that the suction force between the suction portion 8a and the permanent magnet 23 is large. Since the suction member 21 can be easily moved and therefore the driving force of the pneumatic cylinder 22 may be small, the suction member 21 can be made small in size, and the suction member
There is little wear due to sliding of 21 and other parts.

In the above-described embodiment, the shock absorber 1 may be attached to the moving side (load side), and the fixed side may be attached with a stopper for the cushion pad 3 to abut.

In the above-described embodiment, the attracting portion 8a may be composed of the permanent magnet 23 and a permanent magnet of a magnetic pole for attracting. Pneumatic cylinder
Instead of 22, a hydraulic cylinder or solenoid may be used. The method and structure of the shock absorber 1 can be variously modified in addition to the above. Various other members can be adopted as the structure, shape, material and the like of the other members.

[Effect of device]

According to the present invention, the load is not pushed back by the returning means after the load is stopped, and the position of the load after the stop is not displaced. Moreover, the structure is simple.

[Brief description of drawings]

FIG. 1 is a sectional front view of a main part of a shock absorber 1 according to the present invention, and FIG. 2 is a sectional front view of a shock absorber according to the present invention. 1 ... Shock absorber, 2 ... Piston rod, 2a
...... Compression spring (returning means), 5a ...... Pressure chamber, 6 ...... Cover, 8 ...... Piston, 22 ...... Pneumatic cylinder (actuator), 23 ...... Permanent magnet.

Claims (1)

[Scope of utility model registration request] 1. A shock absorber configured to absorb a shock by a piston connected to a piston rod moving in a pressure chamber toward a stroke end, and to restore the piston and the piston rod by a restoring means. In the above, the cover on the stroke end side of the piston is provided with a permanent magnet for attracting the piston, and the permanent magnet has a position where the piston is attracted and a position where the attraction is released by an actuator. The shock absorber is characterized in that it is movable in a direction perpendicular to the axial center of the piston between the two.