| 摘要 |
PROBLEM TO BE SOLVED: To provide a piston in which a ring can be always fixed on the piston side and the ring is prevented from floating during use over a long period of time so that a favorable operation of the piston can be assured and the ring can be prevented from being broken. SOLUTION: The piston comprises a piston body 1 and a ring 2 fitted on an outer periphery of the piston body. The piston body includes on outer periphery of the piston body a plurality of annular grooves 1a, 1b, 1c and 1d arrayed in the axial direction. The ring comprises a ring body 2a extending on the outer periphery of the piston body and inner peripheral side annular projections 2c fitted in the respective annular grooves. The ring body is formed by heating and softening a disk-like synthetic resin base material while applying pressure to the disk-like synthetic resin base material and forcibly fitting the same on the outer periphery of the piston body. The inner peripheral side annular projections are formed of part of the base material which has flowed in the annular grooves. In the piston with the above constitution, annular engagement grooves A, B are formed on both end portions of the piston body in the axial direction. Both ends of the ring body are bent to form hook sections 3d, 3B. The hook sections are fitted in the engagement grooves. COPYRIGHT: (C)2004,JPO&NCIPI
|
