JPH0450449B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fluid pressure cylinder equipped with a brake operated by the cushion pressure of a cushion mechanism.

[Prior Art] Near the stroke end of a cylinder,
By fitting the cushion ring provided on the piston rod into the cushion gasket provided on the cylinder side, the fluid discharge flow path is closed or restricted, the discharged fluid is temporarily confined in the pressure chamber of the cylinder, and the cushion action is achieved. A fluid pressure cylinder configured to exert pressure is already known, as shown in, for example, Japanese Utility Model Application Publication No. 101006/1983.

The known cushion mechanism consisting of the above-mentioned cushion ring and cushion gasket has advantages such as a simple structure, small size, and low cost, and the ability to easily adjust the cushion action using a cushion valve. The cushion pressure confined in the pressure chamber by the cushion mechanism near the stroke end provides a buffering force to the piston, so if the inertia of the piston increases due to an increase in load or speed, the piston will There was insufficient buffering force to stop the piston, and there was a risk that the piston would collide with the cylinder at the end of its stroke.

Furthermore, if the cushioning force of the piston due to the cushioning pressure is increased in order to avoid collision between the piston and the cylinder, the pressure energy of the fluid confined by the cushioning mechanism will cause the piston to bounce back at the end of its stroke. .

In order to solve the above-mentioned drawbacks, the present inventors
The cushion pressure generated by the cushion mechanism is used as a buffering force to stop the piston, and the brake piston is actuated by the cushion pressure, and the brake piston presses the brake shoe against the piston rod to apply braking force to the piston rod. We proposed a fluid pressure cylinder (Utility Application No. 60-51900) and were able to achieve the desired purpose, but since a brake piston is used to transmit the cushion pressure to the brake shoe, the braking The problem was that the mechanism became larger and the number of parts increased.

[Problem to be Solved by the Invention] The problem to be solved by the present invention is to apply a buffering force and a braking force to the piston so that the piston can be reliably stopped at the end of its stroke, and in which the braking mechanism is compact. The object of the present invention is to provide an inexpensive fluid pressure cylinder.

[Means for Solving the Problems] In order to solve the above problems, the present invention has a cushion ring provided on the piston rod fitted into a cushion packing provided on the cylinder side at the stroke end of the cylinder, whereby the cylinder In a fluid pressure cylinder that temporarily confines discharged fluid in a pressure chamber to exhibit a cushioning action, the cushion packing is provided with an annular groove opening on the pressure chamber side, and the cushion packing includes: The present invention is characterized in that a brake shoe is integrally attached, the diameter of which is reduced by displacement of the cushion packing due to the containment fluid pressure, and which presses against the cushion ring.

[Function] Supply high pressure air to one pressure chamber of the cylinder,
When the air in the other pressure chamber is discharged, the piston slides to the air discharge side, and when the cushion ring provided on the piston rod fits into the cushion seal near the stroke end, the pressure chamber is temporarily sealed. Therefore, the pressure in the pressure chamber increases to generate cushion pressure, and this cushion pressure applies a buffering force to the piston. In addition, the cushion packing is displaced by the cushion pressure acting on the groove, and this causes the brake shoe to contract in diameter and press against the cushion ring, so that a braking force is applied to the piston.

Therefore, the piston is reliably stopped by the above-mentioned buffering force and braking force without colliding or rebounding at the end of the stroke.

[Embodiment] FIGS. 1 and 2 show a first embodiment of the present invention, in which a cylinder 1 is provided with a head cover 3 and a rod cover 4 at the end of a cylinder tube 2, as well as tie rods (not shown), etc. It is constructed by being integrally connected by.

On the other hand, the piston 5 sliding inside the cylinder tube 2 is fixed on a piston rod 7 by suitable means, and cushion rings 6, 6 formed on both sides of the piston have a diameter larger than that of the piston rod 7.
is installed.

The head cover 3 and the rod cover 4 each have a recess 11 formed in their center from the piston 5 side, and a cushion packing 16 is disposed on the mouth side of the recess 11 so as to be displaceable by a stopper 19. The bottom side is formed to have a larger diameter than the cushion ring 6, and has a port 14 for supplying and discharging high-pressure air.
It communicates with

The cushion packing 16 has an annular groove 1
5, is made of an elastic material such as rubber, and the above-mentioned cushion ring 6 is closely inserted into the center hole, and the pressure chamber of the cylinder 1 is 20 constitutes a cushion mechanism.

Behind the cushion packing 16, a plurality of brake shoes 17, . . . are integrally attached in the radial direction.
7, . . . are loosely fitted into the recess 11 so as to be able to contract in diameter, with their peripheries inclined toward the piston 5 by the inner edges of the support ring 18 that is fitted and fixed in the recess 11.

The brake shoes 17, . . . have arc-shaped braking surfaces 22, as shown in FIG.
The inner diameter of the virtual circle formed by ... is slightly larger than that of the cushion ring 6 in the non-braking state shown in FIG. When this happens, the braking surface 22 is formed to come into pressure contact with the cushion ring 6 to apply a braking force. Further, the brake shoes 17,... are formed of a metallic material made by sintering metal powder, a cermet made by sintering a porcelain material and metal powder, etc., but it is also possible to line only the braking surface 22 with these materials. Alternatively, or instead of the brake shoes 17, the cushion ring 6 can be made of the above-mentioned material.

Although not shown in the drawings, the contact surfaces 23 of the brake shoes 17, .

Furthermore, a communication hole 24 is provided in the covers 3 and 4 to communicate the pressure chamber 20 of the cylinder 1 with the port 14 (see Fig. 2). An adjustable cushion bubble 25 is provided.

The rod cover 4 is provided with a rod hole 26 as shown in FIG.
It is led out of the cylinder 1 in an airtight manner through the cushion packing 16, brake shoe 17, support ring 18, and rod hole 26 mentioned above.

Reference numeral 27 in FIG. 1 denotes a piston seal that seals between the piston 5 and the cylinder tube 2;
Reference numeral 28 denotes a wear ring, which is attached to a groove formed on the outer periphery of the piston 5.

Next, the operation of the first embodiment will be explained.

In FIG. 1, high pressure air is supplied to the pressure chamber 20 on the head side by a switching valve (not shown), and the air in the pressure chamber 20 on the rod side is transferred to the cushion packing 16 on the rod side and the brake shoe. 17,..., the gap between the support ring 18 and the piston rod 7, and the port 14, which is open to the atmosphere, and the piston 5
is shown sliding to the left in FIG. 1 due to the high pressure air supplied to the pressure chamber 20 on the head side.

Due to the sliding movement of the piston 5, the cushion ring 6
When the rod is inserted into the cushion packing 16, the fluid pressure in the pressure chamber 20 acting on the concave groove 15 of the cushion packing 16 seals the inner and outer peripheral parts of the cushion packing 16, and the pressure chamber 20 on the rod side is sealed. is temporarily sealed, causing the internal pressure to rise rapidly. This increased internal pressure in the pressure chamber 20 acts as a cushion pressure on the piston 5, and also acts on the brake shoe 17,...
is pressed against the support ring 18, the brake shoes 17, .

Due to this displacement, the inner diameters of the brake shoes 17, ... are reduced, so that the braking surfaces 22, ... press against the outer circumferential surface of the cushion ring 6, applying a braking force to the cushion ring 6, and The damping force and the braking force ensure that the piston 5 stops without colliding with the cover at the end of its stroke or bouncing back due to the elastic energy of the cushion pressure.

The air confined in the pressure chamber 20 on the rod side passes through the communication hole 24 and the cushion valve 25 and is gradually released from the port 14. When the cushion pressure decreases, the brake shoes 17,... The elastic restoring force returns to the original state and the braking action is released.

When the switching valve (not shown) is switched to supply high pressure air to the pressure chamber 20 on the rod side, and the air on the head side is released to the atmosphere through the port 14, the high pressure air is transferred from the port 14 on the rod side to the rod side pressure chamber 20. The chamber 20 is fed and the piston 5 slides to the right. The following operations are similar to those described above.

In the above embodiment, the cushion mechanism and the brake mechanism are provided on both the head side and the rod side of the cylinder, but they may be provided on either the head side or the rod side if necessary.

FIG. 4 shows another example of the configuration of the brake shoe in the first embodiment, and this brake shoe 30
has a hollow truncated cone shape and has a slit 31 in the generatrix direction, and the inner surface of the center hole is a braking surface 32. When the conical surface of this brake shoe 30 is pressed against the inner edge of the support ring 18, the slit 3
1, the braking surface 32 is displaced in the direction of diameter reduction by
is pressed against the outer periphery of the cushion ring 6.

FIG. 5 shows a second embodiment of the invention;
A recess 35 is formed in the rod cover 34 of the embodiment, and a support ring 37 of a cushion packing 38 is fitted into the inner wall of the recess 35.

The cushion packing 38 has an annular groove 41 that opens on the pressure chamber side, and is made of an elastic material such as rubber. A hollow cylindrical brake shoe 39 shown in FIG. 6A or B is integrally formed on the inner surface of the cushion packing 38. The inner edge on the piston 5 side has an annular lip 40 into which the cushion ring 6 is tightly fitted.

6A and 6B show a configuration example of the brake shoe 39 in the second embodiment, and the brake shoe 39 in FIG. 6A has slits 39a in the axial direction alternately from both ends of the cylinder to near the other end. is formed,
The brake shoe 39 in FIG. 6B is formed with a slit 39b extending over the entire length in the axial direction.

In the cushion packing 38, the cushion pressure formed by fitting the cushion ring 6 into the lip portion 40 acts in the groove 41, thereby displacing the inner part of the cushion packing 38 in the diametrical direction. , brake shoe 39 and cushion ring 6
are pressed together, but the rest is the same as the first embodiment.

The above-mentioned cushion mechanism and brake mechanism are
It can also be provided on the rod side of the cylinder.

The other configurations and operations of the second embodiment are the same as those of the first embodiment, so detailed explanation thereof will be omitted.

[Effects of the Invention] In the present invention, near the stroke end of the piston, the piston receives a buffering force due to the cushion pressure, and the brake shoe is reduced in diameter by the cushion pressure acting on the concave groove of the cushion packing. By applying braking force to the cushion ring, even when the piston is under a large load and moving at high speed, it not only prevents the piston from colliding with the cylinder, but also prevents the piston from rebounding due to the elastic energy of the fluid generated by the cushioning pressure. The piston can be reliably stopped at the stroke end.

In addition, since the cushion pressure is applied to the brake shoe integrated into the cushion packing,
The braking mechanism can be made compact and inexpensive.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view of the first embodiment of the present invention, FIG. 2 is a top end view of the same, FIG. 3 is a perspective view of the brake shoe shown in FIG. 1, and FIG. 4 is another configuration of the brake shoe. FIG. 5 is a longitudinal sectional view of a main part of a second embodiment of the present invention, and FIGS. 6A and 6B are perspective views of a brake shoe of the second embodiment. 1...Cylinder, 6...Cushion ring, 7
... Piston rod, 15, 41 ... Concave groove, 1
6,38...Cushion patchkin, 17,30,
39... Brake shoe, 18, 37... Support ring, 20... Pressure chamber.

Claims (1)

[Claims] 1. At the stroke end of the cylinder, a cushion ring provided on the piston rod is fitted into a cushion packing provided on the cylinder side, thereby temporarily sealing the discharged fluid in the pressure chamber of the cylinder, In the fluid pressure cylinder that exhibits a cushioning action, the cushion packing is provided with an annular groove opening on the pressure chamber side, and the cushion packing is configured to have a diameter reduced by displacement of the cushion packing due to the containment fluid pressure. do,
A fluid pressure cylinder, characterized in that a brake shoe is integrally attached to press the above-mentioned cushion ring.