Seal structure in hydraulic cylinder, and said hydraulic cylinder

Abstract

The invention provides a seal structure in a hydraulic cylinder, and said hydraulic cylinder, that allows for smooth action of the piston and allows a packing to have longer life. The seal structure is a seal structure between a piston and a cylinder hole in a hydraulic cylinder. A packing 20, having a pair of seal sections 23 (23a), 24 (24a) at the two end sections of an outer peripheral surfacein direction of an axis L, is formed so that the external diameter thereof is less than the diameter of a slid-against surface 3c of a cylinder hole 3, in a state in which the packing 20 is mounted ina concave groove 12 of a sliding surface 4c of a piston 4. In a state in which a compressed fluid is supplied to either of a pair of chambers 3a, 3b of the cylinder hole divided by the piston, a sideend section on the higher-pressure-chamber side of the packing extends in the radial direction Y due to elastic deformation caused by the pressure of the compressed fluid, causing a seal section on the higher-pressure-chamber side to narrow a gap [delta] formed with the slid-against surface of the cylinder hole, or causing the seal section to come into contact with the slid-against surface.

Description

technical field [0001] The present invention relates to a sealing structure between a sliding surface constituted by an outer peripheral surface of the piston and a surface to be slid constituted by an inner peripheral surface of the cylinder bore in a fluid pressure cylinder in which a piston is slidably accommodated in a cylinder bore, and the Fluid cylinder. Background technique [0002] Fluid pressure cylinders that use the pressure of compressed air such as compressed fluid to make the piston slide in the cylinder bore have been widely known in the past, for example, as disclosed in Patent Document 1. In such a fluid pressure cylinder, the cylinder bore is divided into one by the piston. opposite room. At this time, an annular packing, which is a sealing member made of a rubber elastic material, is mounted on the sliding surface formed by the outer peripheral surface surrounding the shaft of the piston, thereby preventing the compressed fluid from passing through the s...

AI Technical Summary

Problems solved by technology

[0004] However, if the above-mentioned packing is maintained in a state of being crimped and stopped on the sliding surface of the cylinder bore for a long period of time, there is a fear of permanent deformation or sticking to the sliding surface.

On the other hand, when the piston is in motion, because the filler is directly affected by the state of the sliding surface (roughness of the sliding surface, state of the lubricating film, etc.), there is a friction between the sliding friction and the lubricating film due to the sliding friction with the sliding surface. Sliding wear and distortion of the packing due to the unevenness of the packing, resulting in damage, deterioration, or adverse effects on the action of the piston (lower operating efficiency, cogging, etc.)

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