Patent ID: 9512924
Filing Date: 2016-12-06
CPC Classification: F16J

Claim Text:
1. A sealing structure, comprising: an annular elastic seal made of rubber and having an inner diameter and an outer diameter, the seal insertable into a recess formed in an inner peripheral surface of a bore through which a reciprocating rod is inserted; and a backup ring configured to support a first surface of the elastic seal, wherein a portion of the elastic seal distal from the first surface of the elastic seal includes an inside diameter lip arranged on the inner diameter of the seal and an outside diameter lip arranged on the outside diameter of the seal, the sealing structure further includes a guide ring having a first axial end and a second axial end, the guide ring provided adjacent an inner circumferential surface of the elastic seal, made of synthetic resin, and integrally including a thin wall portion proximate to the second axial end of the guide ring, the thinwall portion having a first end portion being in contact with the backup ring, and which is configured to support a seal inner peripheral surface of the elastic seal toward the first surface of the elastic seal, and a projecting portion having a semi-circular cross-section proximate to the first axial end of the guide ring and connected to the thin wall portion, fitted into a recess formed in an axially central portion of the seal inner peripheral surface, a thickness of the thin wall portion being different from a thickness of the projecting portion, and having a round V-shaped cross section, wherein the thinwall portion is disposed radially outward from a cylindrical surface of the inner diameter of the guide ring, the projecting portion to form a space between the thinwall portion and the reciprocating rod, an outer peripheral surface of the backup ring includes an inclined guide surface formed such that a diameter of the backup ring gradually increases toward a back surface of the backup ring, a space is formed in a corner portion of the recess located toward the back surface of the backup ring, the space defined by the inner peripheral surface of the bore, a portion of the elastic seal, and a portion of the inclined guide surface, and under pressures, rubber in a surrounding region of a proximal portion of the inside diameter lip of the elastic seal is guided radially outward by the projecting portion, and a portion of the rubber forming the elastic seal is guided into the space along the inclined guide surface.