JPH0218323Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluid pressure cylinder, and is particularly used in cases where there is a risk of misalignment between the axial center of a load and the axial center of the fluid pressure cylinder.

When a load is operated linearly by a fluid pressure cylinder, it is desirable that the axial center of the movement of the load coincides with the axial center of the fluid pressure cylinder, but this cannot always be expected. If there is a risk that these axes may shift, some kind of countermeasure is required, but the most common conventional countermeasure is to prevent eccentricity in the direction of shift at the connection between the load and the tip of the piston rod of the fluid pressure cylinder. is to use possible coupling devices. However, when using such a coupling device, there are disadvantages such as the unavoidable increase in the overall length and size of the device, the labor required for installation, and the high cost of the coupling device. have.

In order to solve the above-mentioned problems, a cylinder device described in Japanese Utility Model Publication No. 56-47369 has been proposed.
This uses a spherical bearing as the rod bush of the fluid pressure cylinder, and has a structure in which the piston rod and the piston are connected so that they can move and rotate over one diameter, and the piston rod rotates around the rod bush. In addition, since the connection position between the piston rod and the piston is changed, even if a bending force is applied to the piston rod, it is released. However, this cylinder device has the disadvantage that if an external force is applied in a direction other than the direction in which the piston rod and piston can move relative to each other, the force cannot be released.
Furthermore, since the structure is complicated, there is a high probability of failure, and the cost is high.

This idea was created in view of the above circumstances.
The object of the present invention is to provide a fluid pressure cylinder with a simple structure that can cope with loads whose axes do not match.

In the present invention, a substantially cylindrical bush that externally fits onto the piston rod is fitted into a substantially cylindrical recess provided in the center of the cylinder cover, and the bush has an inner circumferential surface and an inner end surface. Gaskets are installed to seal between the piston rod and the side wall surface of the recess, and a required gap is provided between the outer peripheral surface of the bush and the inner peripheral surface of the recess. The bushing is configured to be movable in the radial direction within the recess.

Hereinafter, the present invention will be described by way of examples with reference to the drawings.

In the figure, a rod cover 2 and a head cover 3 are attached to both ends of a cylinder tube 1. A piston 4 is slidably fitted inside the rod cover 2, and a piston rod 5 fixed to the piston 4 with a nut 5a covers the rod cover 2. It penetrates and protrudes outward. Rod cover 2 and head cover 3
The piston 4 is provided with ports 8 and 9 communicating with the rod side chamber 6 or the head side chamber 7, respectively, and the piston 4 is provided with a sliding ring 10 for sliding with low friction and a packing 11 for sealing. Rod cover 2 and head cover 3 have tie bolts 1
2 and a nut 13. 14
is Patsukin.

The rod cover 2 is provided with a cylindrical bush 15 that is slidably fitted onto the piston rod 5. The presser plate 17 is fitted into a slightly larger recess 16 and fixed from the outside with bolts 18 to prevent it from coming off. A packing 19 and a scraper 20 are provided on the inner circumferential surface of the bush 15, and a packing 21 is provided on the inner end surface, respectively, to seal between the piston rod 5 or the side wall surface of the recess 16, and to improve sealing performance. In the held state, the bushing 15 is movable in the radial direction within the recess 16, and is also slightly movable in the axial direction due to the elastic compression of the packing 21, so that the bushing 15 is slightly recessed. It is also possible to tilt within the location 16. The piston rod 5 is axially movable through this bushing 15, and
It is possible to move in the radial direction together with the bush 15. The movement of the piston rod 5 in the radial direction causes a force to act on the piston 4 to tilt it with respect to the axis, but normally the amount of tilting movement of the piston due to this action is very small, and the amount of tilting movement of the piston due to this action is very small. This can be absorbed by the clearance between the sliding ring 10 and the elasticity of the packing 11.

In the fluid pressure cylinder configured as described above,
Even if the axis of this fluid pressure cylinder and the axis of the load attached to the tip of the piston rod 5 are misaligned, the piston rod 5 can move in the radial direction together with the bush 15, so no lateral load is applied to the bush 15. Since there are no screws, there is no possibility of twisting or galling, and the bushings 15 and 19 and 2
1. Excessive wear and tear will not occur. In addition, even if the axis misalignment does not cause such damage, conventionally, this increases sliding resistance and impairs smooth operation, especially in hydraulic cylinders designed for low sliding friction. However, with the hydraulic cylinder of the above-described embodiment, there is almost no increase in sliding resistance, and smooth operation is not impaired. The packings 19 and 21 are mainly subjected to sliding motion only in the axial direction or the radial direction, respectively, and the repetition of force in the compressive direction is hardly generated due to misalignment of the axes, so a long life can be expected.

In the above-described embodiment, the bushing 15 has a cylindrical shape, but it may have other shapes, such as a two-stage cylindrical shape, an abacus bead shape, etc., as long as it is movable in the radial direction within the recess 16 and can be sealed. Patsukin 1
Various shapes can be adopted for the shapes of 9 and 21. If the misalignment of the axes is expected to be quite large, it is advisable to adopt a radially movable structure like the bush 15 or a spherical connection structure to connect the piston 4 and the piston rod 5. .

As described above, the present invention, despite its simple structure, can handle loads that do not match the axis of the fluid pressure cylinder, and does not require any special joints, which prevents the device from becoming larger and more complicated. be able to. When the bushing moves in the radial direction within the recess, the packing is not directly compressed by the movement, so the increase in sliding resistance due to misalignment of the axis can be reduced, and the packing can be compressed. You can expect a long life.

[Brief explanation of the drawing]

The figure is a sectional view showing an embodiment of the fluid pressure cylinder of the present invention. 1... Cylinder tube, 2... Rod cover (cylinder cover), 3... Head cover (cylinder cover), 4... Piston, 5... Piston rod, 15... Bush, 16... Recess, 19, 21
...Patsukin.

Claims (1)

[Scope of utility model registration request] A fluid pressure cylinder comprising a piston that slides within a cylinder tube provided with cylinder covers at both ends, and a piston rod that is connected to the piston and projects outward through at least one of the cylinder covers. A substantially cylindrical bushing externally fitted onto the piston rod is fitted into a substantially cylindrical recess provided at the center of the cylinder cover, and the bushing has the above-mentioned bushings on its inner peripheral surface and inner end surface. Gaskets are installed to seal between the piston rod and the side wall surface of the recess, and a required gap is provided between the outer peripheral surface of the bush and the inner peripheral surface of the recess. A hydraulic cylinder, wherein the bushing is configured to be radially movable within the recess.