JP2000179691A - Packing structure of piston, etc. - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the thickness of a sliding body by arranging a rubber magnet with permanent magnetism and elasticity and a seal ring which is urged thereby from its inner side and brought into slidable contact with an inner circumferential surface of an actuator body in an overlapped manner inside a packing groove provided in the sliding body such as a piston. SOLUTION: Only a packing groove 12 is provided on an outer circumferential surface of a piston 11 sliding in a cylinder body (actuator body) 10. A rubber magnet 13 and a seal ring 14 which is urged thereby from its inner side and brought into slidable contact with an inner circumferential surface of the cylinder body (actuator body) 10 are concentrically arranged inside the packing groove 12 in an overlapped manner. Thus, the elastic force by the rubber magnet 13 is constantly applied to the seal ring 14, and the outer circumferential surface of the seal ring 14 is constantly pressed against an inner circumferential surface of the cylinder body 10. The thickness of a sliding body such as a piston can be reduced thereby, and the overall length of the hydraulic actuator can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packing for sealing between a sliding member such as a piston and an inner peripheral surface of an actuator body in a hydraulic actuator such as a pneumatic cylinder or a hydraulic cylinder having a sliding member such as a piston. Regarding the structure.

[0002]

2. Description of the Related Art Conventionally, in a fluid pressure actuator such as a pneumatic cylinder or a hydraulic cylinder, when the position of the piston is detected from outside the actuator body by a magnetic sensitive sensor such as a magnetic proximity switch, as shown in FIG. A packing groove 2 and a magnet groove 3 are provided on the outer peripheral surface of the rubber member 1 in the sliding direction of the piston.

[0003]

Therefore, the piston 1
Of the actuator body 6
Had to be long.

[0004] It is an object of the present invention to reduce the thickness of a sliding body such as a piston and reduce the overall length of a fluid pressure actuator by adopting a conventional structure in which a packing groove and a magnet groove can be shared by one groove. It is to become.

[0005]

According to the present invention, there is provided a rubber magnet having permanent magnetism and elasticity inside a packing groove provided in a sliding member such as a piston, and a rubber magnet which is urged from the inside by the inside thereof to form an actuator body. A seal ring that slides on the inner peripheral surface is disposed so as to overlap.

[0006] The rubber magnet is pushed by a seal ring that is in sliding contact with the inner peripheral surface of the actuator body, and is housed in the packing groove in a compressed state.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a pneumatic cylinder will be described below.

As shown in the overall view of FIG. 1 and the partially enlarged view of FIG. 2, only one groove, that is, a packing groove 12 is provided on the outer peripheral surface of a piston 11 which slides in a cylinder body (actuator body) 10. This packing groove 1 is not
Inside 2, a rubber magnet 13 and a seal ring 14 urged from the inside and slidably in contact with the inner peripheral surface of the cylinder body 10 are arranged concentrically on top of each other.

The rubber magnet 13 is a mixture of a rubber material such as NBR rubber and a permanent magnetic material, and has both permanent magnetism and elasticity.

The seal ring 14 is made of a hard synthetic resin having excellent wear resistance such as ethylene tetrafluoride.

The rubber magnet 13 includes a seal ring 14
Is pressed into the packing groove 12 in a compressed state.
Thus, the outer peripheral surface of the seal ring 14 is constantly pressed against the inner peripheral surface of the cylinder body 10.

Although not shown, a magnetically responsive sensor such as a magnetic proximity switch for detecting the position of the piston 11 in response to a magnetic force from the rubber magnet 13 is attached to the outside of the cylinder body 10.

In the above description, the present invention is applied to a piston sliding portion of a pneumatic cylinder, but can be applied to a sliding member other than a piston.

[0014]

According to the present invention, a rubber magnet having permanent magnetism and elasticity and a seal ring are superposed and arranged inside one packing groove provided in a sliding body such as a piston,
Since the seal ring is in sliding contact with the inner peripheral surface of the actuator body by the elasticity of the rubber magnet, the thickness of a sliding body such as a piston can be reduced, and the overall length of the fluid pressure actuator can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a pneumatic cylinder to which the present invention is applied.

FIG. 2 is a sectional view showing a packing structure according to the present invention in detail by enlarging a part of FIG. 1;

FIG. 3 is a sectional view of a conventional pneumatic cylinder having a packing structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Cylinder main body 11 Piston 12 Packing groove 13 Rubber magnet 14 Seal ring

Claims (2)

[Claims] In a fluid pressure actuator for detecting the position of a sliding body such as a piston from the outside of an actuator body by a magnetically responsive sensor, a rubber having permanent magnetism and elasticity is provided in a packing groove provided in the sliding body. A packing structure for a piston or the like, wherein a magnet and a seal ring which is urged from the inside thereof and slidably contacts the inner peripheral surface of the actuator body are arranged in an overlapping manner. 2. The packing structure for a piston or the like according to claim 1, wherein the rubber magnet is housed in the packing groove in a compressed state by being pushed by a seal ring slidingly contacting the inner peripheral surface of the actuator body.