Patent ID: 8739684

Claim:
A fluid pressure apparatus comprising: a housing including a slide hole formed therein; a partitioning member that moves in an axial direction along an interior of the slide hole; and a packing that is installed on an outer circumference of the partitioning member, wherein the packing comprises an annular seal member made of an elastic material, and at least one support ring made of a low-friction material, the seal member being installed in an annular packing installation groove formed on an outer circumference of the partitioning member, the at least one support ring being mounted on an outer circumference of the seal member; the seal member includes, on the outer circumference thereof, a sealing projection that contacts an inner circumferential surface of the slide hole, and at least one shoulder portion formed on both sides or one side of the sealing projection and which project outwardly from the packing installation groove; the at least one support ring is provided on both sides or one side of the sealing projection, and protrudes from the seal member in an axial direction thereof; and the at least one support ring includes a support surface, which is parallel on an outer circumference thereof with an axial direction of the partitioning member, and wherein when a transverse load does not act on the partitioning member, the sealing projection is pressed against the inner circumferential surface of the slide hole and thereby is elastically compressed and deformed, and the support surface of the at least one support ring contacts with the inner circumferential surface of the slide hole while an inner circumferential surface of the at least one support ring is out of contact with the outer circumference of the partitioning member; and when at least a certain amount of transverse load acts on the partitioning member, the sealing projection is pressed against the inner circumferential surface of the slide hole and thereby is elastically compressed and deformed, and the support surface of the at least one support ring contacts with the inner circumferential surface of the slide hole while the inner circumferential surface of the at least one support ring contacts with the outer circumference of the partitioning member.