Patent ID: 8176939

Claim:
A fluid pressure equipment provided with a low-sliding packing, having a housing provided with a flow-passage hole through which a pressure fluid flows and sliding member slidable in the flow-passage hole in an axial direction of the flow-passage hole, in which a packing housing groove is formed in an outer periphery of the sliding member, and a ring-shaped packing is housed in the packing housing groove, characterized in that: the packing comprises a ring-shaped inner-peripheral seal portion provided with an arc-shaped inner-peripheral seal face brought into contact with a groove bottom of the packing housing groove, a ring-shaped outer peripheral seal portion provided with an arc-shaped outer-peripheral seal face in sliding contact with a hole inner face of the flow-passage hole, and a ring-shaped intermediate flexible portion formed by providing a ring-shaped recess groove with a flat bottom in a region between the inner-peripheral seal portion and the outer-peripheral seal portion on both right and left side faces of the packing and curved by an action of a fluid pressure; the inner-peripheral seal portion and the outer-peripheral seal portion have both right and left flat side faces in parallel with each other, thickness of the inner-peripheral seal portion and the outer-peripheral seal portion is equal to each other and formed smaller than a groove width of the packing housing groove; and the intermediate flexible portion has both right and left flat side faces in parallel with each other, the thickness of the intermediate flexible portion is formed smaller than the thickness of the inner-peripheral seal portion and the outer-peripheral seal portion, and a ring width of the intermediate flexible portion in the packing radial direction is formed equal to or larger than the thickness of the intermediate flexible portion.