| 摘要 |
PURPOSE:To secure smooth sliding motion in a piston, by installing a cup seal at the side of a pressure chamber of the spherical body piston and also a pressing force transmitting member at the opposite side of the chamber, respectively. CONSTITUTION:A metallic spherical body piston 3 contact slidingly on an inner circumference of a cylinder hole 2 is fitly inserted into this cylinder hole 2 formed in a cylinder body 1 free of movement toward a cylinder shaft. The backside 5b formed in a concave spherical surface upon molding a hard ring 5a on the peripheral edge of a rubber cup seal 5 is stuck fast to a surface adjoining a hydraulic chamber 4 of the spherical body piston 3. In addition, a ball receiving part 8a at the tip expanded in diameter of a push rod 8 comes into contact with the opposite side of the hydraulic chamber of the spherical body piston 3. |
