| 摘要 |
PROBLEM TO BE SOLVED: To provide a piston in which a ring can be constantly fixed to a piston to prevent it from floating during long-period use, and improve actuation of the piston, and in which breakage of the ring can be prevented. SOLUTION: This piston comprises a piston main body 1, and the ring 2 engaged on the outer circumference of the piston body. The piston body is provided with a plurality of circular grooves 1a, 1b, 1c, 1d, 1e, and 1f axially formed in an outer circumference. The ring is composed of a ring body 2a provided along the outer circumference of the piston body, formed by pressurizing and pushing a disc of synthetic resin base material to the outer circumference of the piston body while it is heated and softened to be molded, and an inner circumferential side circular projection 2c engaged by flowing into each circular groove. Both end parts 2d and 2B of the ring body are bent to form bent parts, and each bent part is engaged in each circular groove in each side. Taper surfaces are formed in the outer circumference of each bent part to start from positions c and d corresponding to axial inner side of inner opening edges a and b of the circular groove in each side. COPYRIGHT: (C)2004,JPO&NCIPI
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