JPH0329604Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fluid pressure cylinder equipped with a brake operated by the cushion pressure of a cushion mechanism.

[Prior Art] 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, and the cushioning action is performed. For example, a fluid pressure cylinder designed to exert
As shown in the publication, this is already known.

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

Additionally, 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 elastic energy of the fluid confined in the cushioning mechanism will cause the piston to rebound at the end of its stroke. There is a drawback that the kinetic energy of the piston, which consists of load and speed, is limited and cannot be increased.

In order to solve the above-mentioned drawbacks, the inventors of the present invention
As shown in FIG. 2, brake shoes 43a and 43 are attached to a piston rod 41 to which a piston 42 is fixed.
b loosely fit into the piston 42 and the brake shoe 4.
Brake spring 44 between 3a and 43b
a, 44b are provided, and the brake shoes 43a, 43b are brought into contact with the pivots 45a, 45b near the stroke end of the piston 42, so that the brake shoes 43a, 43b are tilted with respect to the piston rod 41. Fluid cylinder that applies braking force to the piston rod 41
(Utility Model No. 61-175604)).

The previously proposed fluid pressure cylinder has the advantage of being able to apply braking force to the piston rod with a simple configuration, but in order to reliably stop a piston driven at high load and high speed at the stroke end, it is necessary to The braking force of the brake shoe had to be increased by some means.

[Problems to be solved by the invention] The invention uses a braking mechanism with a simple structure to apply braking force to the piston, and also applies a buffering force due to cushion pressure to the piston, so that the piston can be operated under high loads and high speeds. Even when driving
The problem to be solved is to obtain a compact hydraulic cylinder that can be reliably stopped at the end of its stroke.

[Means for solving the problem] The present invention is a fluid pressure cylinder that drives the piston by supplying and discharging high-pressure air to both sides of the piston in the cylinder. A brake shoe is slidably fitted onto the piston rod between the piston rod and the stopper mounted at the same position, and applies a braking force by tilting with respect to the piston rod.
The inside of the cylinder is divided into a cushion chamber between the piston and the brake shoe, and a pressure chamber between the brake shoe and the cylinder cover, and air from the pressure chamber to the cushion chamber is passed around the outer periphery of the brake shoe, A one-way packing that blocks air from the cushion chamber to the pressure chamber is installed, and a brake spring is provided between the brake shoe and the piston to bring the brake shoe into contact with the stopper, and the eccentric position of the cylinder cover is The above-mentioned problem has been solved by adopting a technical means of fixing the pivot on which the brake shoe comes into contact.

[Function] When high-pressure air is supplied to one pressure chamber of a fluid pressure cylinder and the air from the other pressure chamber is exhausted, the one-way packing installed on the brake shoe on the high-pressure air supply side releases the air from the pressure chamber. Since the air flows into the cushion chamber, the piston slides toward the pressure chamber on the air discharge side.

When the brake shoe comes into contact with the eccentrically provided pivot near the stroke end of the piston and prevents the brake shoe and the piston rod from sliding together, an eccentric force acts on the brake shoe and the brake shoe Since the Y is inclined with respect to the axis of the piston rod, the corners of its inner peripheral surface come into pressure contact with the piston rod, and a braking force is applied to the piston rod. In this case, the brake shoe slides slightly in the direction of the piston, and the resulting increase in the biasing force of the brake spring also increases the braking force of the brake shoe. In addition, the air in the cushion chamber on the discharge side is prevented from flowing from the outer surface of the brake shoe toward the pressure chamber by the one-way packing, so the air is temporarily confined in the cushion chamber and cushion pressure is generated. This cushion pressure provides a buffering force to the piston, so even when the piston is driven under high load and at high speed, it will not collide with the cylinder or bounce at the end of its stroke, and the piston will maintain its stroke. Stop at the end.

Next, when the supply and discharge of high-pressure air to the pressure chamber is reversed, the inclined brake shoe returns to its original state and the braking force is released, so that the piston slides in the opposite direction without any hindrance.

[Embodiment] FIG. 1 shows an embodiment of the present invention, in which a cylinder 1 is constructed by screwing a head cover 3 and a rod cover 4 onto the end of a cylinder tube 2.

On the other hand, the piston rod 6 of the piston 5 sliding in the cylinder 1 has a piston mounting step 7, and the piston 5 is brought into contact with the step 7.
A brake show guide 9 is fitted onto the distal end side of the piston rod 6, and is fixed by a stopper 10a which is screwed onto a nut 11.
Further, a stopper 10b is fixed to the opposite side of the piston rod 6 from the side on which the brake shoe guide 9 is fitted, at a position where the distance from the piston 5 is equal to that of the brake shoe guide 9, by appropriate means. .

Both end surfaces of the piston 5 and stoppers 10a, 1
0b, brake shoes 15a and 15b are provided with a groove 16 on the outer peripheral surface and an annular groove 17 on the side surface on the piston side. The brake shoes 15a, 15b are loosely fitted so as to be movable, and the brake shoes 15a, 15b are
The biasing force of coil-shaped brake springs 20a, 20b installed between the groove 17 and the piston 5 always urges the brake springs to contact the stoppers 10a, 10b.

The brake shoes 15a, 15b are made of a metallic material made by sintering metal powder, a cermet made by sintering a porcelain material and metal powder, or the like. It may also be lined.

In addition, a one-way packing 21 having a U-shaped cross section and open on the piston 5 side is attached to the concave groove 16 on the outer peripheral surface of the brake shoes 15a and 15b so that the outer lip 22 of the packing 21 is in close contact with the cylinder tube 2. By the packing 21, the cylinder 1 is closed to the pressure chambers 23a, 23b between the covers 3, 4 and the brake shoes 15a, 15b and the brake shoes 1.
5a, 15b and cushion chambers 24a, 24b between the piston 5. The gaps between the brake shoes 15a, 15b and the piston rod 6 limit the amount of air in the cushion chambers 24a, 24b that flows out into the pressure chambers 23a, 23b.
The cushion pressures of a and 24b are determined.

The one-way packing 21 includes pressure chambers 23a,
23b to the cushion chambers 24a, 24b, the air causes the outer lip 22 to pass away from the inner wall of the cylinder tube 2, while the air flows in the opposite direction. This serves to prevent the outer lip portion 22 from coming into close contact with the inner wall of the cylinder tube 2.

The head cover 3 and the rod cover 4 have pivots 25a and 25b fixed at eccentric positions on their inner end surfaces, and holes 26a and 26b are provided at the center of their inner surfaces through which the stoppers 10a and 10b can be inserted together with the piston rod 6. Hole 26a,
Pressure chambers 23a, 23 of cylinder 1 through 26b
Ports 27a and 27b for supplying and discharging high-pressure air are opened to b. Further, the rod cover 4 has a rod hole 28 through which the piston rod 6 is led out.

On the other hand, high-pressure air from the high-pressure air source 30 is piped to be supplied to and discharged from the ports 27a and 27b via the electromagnetic switching valve 1 and the air supply and discharge pipes 32a and 32b. , 32b are each provided with a speed controller 33.

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

In FIG. 1, the electromagnetic switching valve 31 is energized, and high-pressure air from the high-pressure air source 30 passes through the electromagnetic switching valve 31, the supply/discharge pipe 32a, and the speed controller 33, and from the port 27a to the pressure chamber 23a on the head side. Indicates that the power is being supplied to the In this state, the outer lip 22 of the one-way packing 21 attached to the concave groove 16 of the brake shoe 15a is separated from the cylinder tube 2 by high pressure air, so the high pressure air flows inside and outside the brake shoe 15a. It is also supplied to the cushion chamber 24a through the gap.

On the other hand, the air in the pressure chamber 23b on the rod side is released to the atmosphere through the port 27b, the speed controller 33, the supply/discharge pipe 32b, and the electromagnetic switching valve 31, so the piston 5 slides to the left in FIG. move. FIG. 1 shows a state in which the piston 5 has moved to the left and the brake shoe 15b has come into contact with the pivot 25b.

When the brake shoe 15b comes into contact with the eccentrically provided pivot 25b, the brake shoe 15b is partially pressed by the pivot 25b and is inclined with respect to the axis of the piston rod 6, so that a part of its inner peripheral surface comes into pressure contact with the outer peripheral surface of the piston rod 6, applying braking force to the piston rod 6, reducing the gap between the brake shoe 15b and the piston rod 6, and reducing the air flow by the one-way packing 21 installed in the groove 16. Since the blocking restricts the amount of air flowing out of the cushion chamber 24b, a cushion pressure is generated in the cushion chamber 24b, and the piston 5 receives a damping force.
In this case, the brake shoe 15b slides slightly in the direction of the piston, but the resulting increase in the biasing force of the brake spring 20b also promotes the inclination of the brake shoe 5b, increasing the braking force. Therefore, in combination with the buffering force that the piston 5 receives, even if the piston 5 is driven at high speed and under high load, it will stop at the end of its stroke.

Next, when the electromagnetic switching valve 31 is de-energized and the supply and discharge of high-pressure air to the pressure chambers 23a and 23b is reversed, the brake shoe 15b returns from the tilted state due to the backward movement of the piston rod 6, and the braking force is released. Therefore, the piston 5 slides toward the head side without any trouble, receives an action similar to the above-mentioned action near the stroke end, and stops at the end of the stroke.

In the above embodiment, a cushion mechanism consisting of a cushion ring and a cushion packing, and a brake mechanism consisting of a brake shoe, a brake spring, etc. are provided on both the head side and the rod side of the cylinder. It can be provided on either the side or the rod side.

[Effects of the invention] The present invention not only applies braking force to the piston by pressing the pivoted brake shoe against the piston rod near the stroke end of the piston, but also uses a one-way packing attached to the outer periphery of the brake shoe. by blocking the flow of air from the cushion chamber to the pressure chamber at the outer periphery of the brake shoe to generate cushion pressure in the cushion chamber,
This also causes a buffering force to act on the piston, so even if the piston is driven at high speed and under high load, it can be reliably stopped at the end of its stroke.

Furthermore, the present invention is simple and inexpensive since the brake mechanism is composed of a brake shoe fitted loosely into the piston rod, a brake spring that applies a biasing force to the brake shoe, a stopper on the piston rod, and a pivot provided on the cover. Not only that, but the cylinder can be formed very compactly, and its structure is suitable for application to small cylinders, and it is possible to obtain a compact cylinder with a brake that has a cushioning action that has not been available in the past. can.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view showing an embodiment of the present invention, and FIG. 2 is a longitudinal sectional front view of a previously proposed fluid pressure cylinder. 1... Cylinder, 5... Piston, 6... Piston rod, 10a, 10b... Stopper, 16
... Concave groove, 15a, 15b ... Brake shoe,
20a, 20b...Brake spring, 21...
...One-way packing, 23a, 23b...Pressure chamber, 24a, 24b...Cushion chamber, 25a,
25b...Pivot.

Claims (1)

[Scope of utility model registration request] In a fluid pressure cylinder that drives the piston by supplying and discharging high pressure air to both sides of the piston in the cylinder, on the piston rod between the piston fixed to the piston rod and a stopper installed at a necessary braking distance from the piston, A brake shoe that applies braking force by tilting with respect to the piston rod is slidably fitted loosely, and the pressure inside the cylinder is reduced between the cushion chamber between the piston and the brake shoe, and the pressure between the brake shoe and the cylinder cover. A one-way packing is installed on the outer periphery of the brake shoe to allow air to pass from the pressure chamber to the cushion chamber and to block air from the cushion chamber to the pressure chamber. A hydraulic cylinder with a brake, characterized in that a brake spring is provided between the piston and the brake shoe to bring the brake shoe into contact with the stopper, and a pivot on which the brake shoe comes into contact is fixed at an eccentric position of the cylinder cover.