Patent ID: 8302526

Claim:
A seal structure in a fluid pressure device having a cylinder tube including an inner cylinder surface defining a chamber in the cylinder tube, an open end of the cylinder tube and a cover member that closes said open end, said fluid pressure device further having a piston displaceable along the cylinder chamber while in sealing contact with the inner cylinder surface, the piston being mounted to a piston rod that extends through the cover member, the seal structure comprising: a rigid plate shaped base body formed in a plate shape; a seal member formed from an elastic material and installed integrally on said base body, wherein said base body and seal member are installed in the opening end of said cylinder tube, wherein said base body and said seal member are together gripped between said cylinder tube and said cover member to form a first seal element that airtightly seals the joint between said cylinder tube and said cover member, wherein said base body and said seal member both extend radially inward from said inner cylinder surface along which the piston is displaceable, and toward said piston rod, and wherein said seal member further comprises a second seal element surrounding and engaging an outer circumferential surface of said piston rod to airtightly seal the chamber in the cylinder tube from the location where the piston rod extends through the cover member.