JPH0710087Y2 - Fluid pressure cylinder with cushion device - Google Patents

Description

The present invention relates to a fluid pressure cylinder having a cushion device for decelerating and stopping a piston, and more particularly, to a fluid pressure cushion device and a magnetic force cushion device utilizing an attraction force. And a fluid pressure cylinder provided with.

[Prior Art] A cushion packing and a cushion ring tightly fitted into the cushion packing are provided, and the piston is decelerated by the air pressure temporarily enclosed by fitting the cushion ring into the cushion packing near the end of the stroke of the piston. Pneumatic cylinders with pneumatic cushioning devices for stopping are well known prior to filing the application.

However, the containment air pressure in the above-mentioned known pneumatic cushioning device is low at the beginning of the cushion stroke where the cushion ring fits into the cushion packing and becomes higher as it approaches the end of the cushion stroke, so there is a problem that the cushioning efficiency of the piston is low.

On the other hand, a pneumatic cylinder provided with a magnet on each of the facing surfaces of the cylinder and the piston, and a magnetic force cushion device for decelerating and stopping the piston by the repulsive force of the magnet near the stroke end of the piston is also known before the application of the present application. (For example, see Japanese Utility Model Laid-Open No. 62-183107).

However, since the repulsive force of the magnet in the magnetic force cushion device increases as the piston approaches the end of the stroke and the distance between the magnets decreases, the cushioning efficiency of the piston is low as in the pneumatic cushion device,
In addition, since a large repulsive force acts on the piston at the end of the stroke of the piston, there is a problem that the thrust of the pneumatic cylinder at the end of the stroke decreases.

[Problems to be Solved by the Invention] An object of the present invention is to provide a fluid pressure cushioning device and a magnetic force cushioning device utilizing the attraction force of a magnet together to provide a high piston cushioning efficiency and a reduction in thrust at the end of the stroke. There is no provision for a hydraulic cylinder.

[Means for Solving the Problems] In order to solve the above problems, a fluid pressure cylinder with a cushion device of the present invention includes a cushion packing and a cushion ring tightly fitted into the cushion packing, and is provided near the stroke end of the piston. A fluid pressure cushion device for decelerating and stopping the piston by the fluid pressure temporarily enclosed by fitting the cushion ring into the cushion packing, a first magnet fixed to the piston, and an outer sliding relative to the piston. Possible and above first
End of the stroke of the piston, and a second magnet that is attracted to the magnet of the second magnet, and a push rod that is provided on the second magnet and that extends to the opposite side through the piston and contacts the cylinder near the end of the stroke of the piston. A magnetic force cushion device for separating the second magnet attracted to the first magnet in the vicinity and decelerating and stopping the piston by the attraction force between the magnets is provided.

Further, in order to achieve the same object, in the above fluid pressure cylinder with a cushion device, the second magnet is provided with a reinforcing plate that abuts on the piston and forms a gap between the second magnet and the first magnet. I am trying.

[Operation] When the piston slides near the end of the stroke and reaches the cushion stroke where the cushion ring fits into the cushion packing, the temporarily confined fluid pressure on the discharge side rises and the push rod hits the cylinder. Since the second magnet is brought into contact with and separated from the first magnet that moves integrally with the piston, the piston is decelerated by the combined force of the braking force due to the confining fluid pressure and the braking force due to the attraction force between the magnets to end the stroke. Stop as a buffer.

In this case, since the attraction force between the magnets is the largest at the starting end of the cushion stroke, it is possible to apply a large braking force to the piston at the beginning of the cushion stroke to enhance the buffer efficiency. Also, the attraction force between the magnetic forces decreases as the cushion stroke progresses, but the braking force due to the contained fluid pressure increases rapidly as the cushion stroke progresses, so the total braking force acting on the piston is averaged over the entire cushion stroke. Be converted.

At the end of the stroke of the piston, the distance between the magnets is maximum and the attraction force becomes extremely small, so the thrust of the cylinder does not decrease at the end of the stroke.

When the piston slides in the opposite direction, the second magnet is attracted to the first magnet. In this case, if the second magnet is provided with a reinforcing plate that comes into contact with the piston and forms a gap between the magnets, collision between the magnets can be prevented.

[Embodiment] FIGS. 1 and 2 show a first embodiment of the present invention, in which a pneumatic cylinder 1 comprises a fluid pressure cushion device 2 and a magnetic force cushion device 3 utilizing the attraction force of a permanent magnet. ing.

The cylinder of the pneumatic cylinder 1 is formed by integrally connecting the cylinder tube 5, the head cover 6a, and the rod cover 6b by appropriate means, and the piston 8 and the cushion ring 9a on both sides thereof are formed at the reduced diameter portion of the tip of the piston rod 7. , 9
b is attached, and the cylinder is partitioned by the piston 8 into pressure chambers 10a and 10b.

The covers 6a, 6b are pressure air supply / discharge ports 12a, 12b, recesses 13a, 13b that are opened at the ports and open on the pressure chamber side, and flow paths 14a, 14b that connect the pressure chambers 10a, 10b to the recesses 13a, 13b. Cushion packings 15a, 15b in which the cushion rings 9a, 9b are tightly fitted are attached to the open edges of the recesses 13a, 13b, and the fluid pressure cushion device 2 is constituted by these. Further, needle valves 16a, 16b for adjusting the opening of the flow paths 14a, 14b are provided in the flow paths 14a, 14b.

The piston 8 has a first permanent magnet 20a fixed to the side surface,
20b and a slidable second permanent magnet 21a, 21b on the outside thereof are provided, and these magnets 20a and 21a and 20b and 21b are magnetized so as to attract each other.

The second magnets 21a, 21b are provided with push rods 22a, ..., 22b, .., and axial through holes 23a, .., 23b, .. (See FIG. 2), the push rods 22a, ..., 22b, ... Are the axial holes formed in the piston 8 and the first magnets 20a, 20b, and the through holes 2 described above.
3b, ..., 23a, ..., Extending from the magnets 21b and 21a by a cushion stroke 1 and sealed by a seal ring provided on the outer periphery of the hole formed in the piston 8,
The magnetic force cushion device 3 is configured by these magnets and the push rod.

Next, the cushioning action of the first embodiment will be described.

In FIG. 1, the piston 8 strokes toward the head side by the pressurized air supplied to the pressure chamber 10b, and the cushion ring 9a
Fit into the cushion packing 15a, and push rod 2
.. shows the state where the cushion stroke starts, with the tips of 2a, ... Contacting the head cover 6a. Magnets 20a, 21a and 20b
And 21b are adsorbed.

When the cushion ring 9a is fitted into the cushion packing 15a, the exhaust air from the pressure chamber 10a is contained,
The piston 8 is decelerated by this containment air pressure, and the contained air is contained in the flow passage 14a, the needle valve 16a and the recess.
It gradually flows out through 13a.

The braking force Fa by the fluid pressure cushion device 2 rapidly increases as the piston 8 approaches the end of the cushion stroke l, as shown in FIG.

When the piston 8 plunges into the cushion stroke, the push rods 22a, ... Contact the head cover 6a, and the second magnet 21a stops at that position against the attraction force with the first magnet 20a. The piston 8 is also decelerated by the attraction force between the magnets 20a and 21a. This attraction force is large when the distance between the magnets is small, and is small when the distance is large. Therefore, the braking force Fm by the magnetic force cushion device 3 is
As shown in FIG. 4, it is the largest at the starting end of the cushion stroke l, and then rapidly decreases.

Therefore, the total braking force Ft acting on the piston 8 during the cushion stroke is averaged as shown by the dotted line in FIG. 4 and the fluctuation is small, and the piston 8 is decelerated by the averaged total braking force Ft. It is stopped at the end of the stroke as a buffer. In this case, since the braking force Fm of the magnetic cushion device 3 is the largest at the starting end of the cushion stroke, the cushioning efficiency of the piston is high, and the adsorption force is extremely small at the stroke end of the piston 8 (cushion stroke end). The thrust does not decrease at the end of the stroke.

When the supply and discharge of the pressurized air in the pressure chambers 10a and 10b is reversed, the piston 8 slides to the rod side. The cushion action acting on the piston 8 near the end of the stroke on the rod side is
It is the same as the case of the head side.

FIG. 3 shows an essential part of the second embodiment of the present invention. The magnets 21a and 21b in the second embodiment are provided with a reinforcing plate 25 on the pressure chamber side, the tip of the bent portion of which abuts against the piston 8 and is pushed. rod
22a and 22b are formed integrally with the reinforcing plate 25.

The reinforcing plate 25 is configured so that when the tip of the bent portion comes into contact with the piston 8, a gap b is created between the magnets 20a and 21a and 20a and 21a, whereby the magnets 20a, 21a and 20b. And 21b collision and magnet at end of stroke
The contact between the covers 21a, 21b and the covers 6a, 6b is prevented.

Other configurations and operations of the second embodiment are the same as those of the first embodiment.

[Effects of the Invention] The fluid pressure cylinder of the present invention is provided with a fluid pressure cushion device having a large braking force in the latter half of the cushion stroke and a magnetic cushion device utilizing the attraction force of a magnet having a large braking force in the first half of the cushion stroke. Since the braking force acting on the piston during the cushion stroke is averaged, the piston can be efficiently decelerated and stopped at the end of the stroke in a buffer manner.

Further, since the magnetic force cushion device using the attractive force has an extremely small attractive force at the end of the stroke, even if the magnetic force cushion device is used, the thrust of the fluid pressure cylinder does not decrease at the end of the stroke.

Further, since the second magnet is provided with the reinforcing plate that comes into contact with the piston and forms a gap between the second magnet and the first magnet, it is possible to prevent collision between the magnets and prolong the life of the magnets.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of a first embodiment of the present invention with a part omitted, FIG. 2 is an exploded perspective view of an essential part of the same as above, and FIG. 3 is a longitudinal section showing an essential part of a second embodiment of the present invention. The front view and FIG. 4 are diagrams showing the relationship between the cushion stroke and the braking force. 1 ... Fluid pressure cylinder, 2 ... Fluid pressure cushion device,
3 ... Magnetic cushion device, 8 ... Piston, 9a, 9b ...
… Cushion ring, 15a, 15b …… Cushion packing, 20a, 20b …… First magnet, 21a, 21b… Second magnet,
22a, 22b …… Push rod, 25 …… Reinforcement plate.

Claims (2)

[Scope of utility model registration request] 1. A cushion packing and a cushion ring tightly fitted in the cushion packing, wherein the piston is decelerated by the fluid pressure temporarily contained by fitting the cushion ring into the cushion packing near the stroke end of the piston. A fluid pressure cushion device to be stopped, a first magnet fixed to the piston, a second magnet outside the first magnet, which is slidable relative to the piston and attracted to the first magnet, and the second magnet. A push rod that extends through the piston on the opposite side and abuts the cylinder near the stroke end of the piston, and separates the second magnet attracted to the first magnet near the stroke end of the piston. And a magnetic force cushion device for decelerating and stopping the piston by the attractive force between the magnets. Cushion device with a fluid pressure cylinder, wherein the door. 2. The fluid pressure with a cushion device according to claim 1, wherein the second magnet is provided with a reinforcing plate that comes into contact with the piston and forms a gap between the second magnet and the first magnet. Cylinder.