| 摘要 |
PROBLEM TO BE SOLVED: To provide a seal ring for a variable valve timing system which is hardly damaged by the expansion of the ring at installation even if the ring is made thick in thickness, can be complicated in shape by injection molding, and is low in oil leakage, low in friction, and high in wear resistance.SOLUTION: In a variable valve timing system which comprises a cam shaft 5 for driving a suction valve and an exhaust valve of an internal combustion engine, an inside rotating body 3 fixed to the cam shaft 5, an outside rotating body 4 which rotates so as to be turnable relatively to the inside rotating body 3 by a working fluid at a change of the valve opening/closing timing of the suction valve or the exhaust valve, and a shaft body 2a which is arranged at an internal periphery of the inside rotating body 3 so as to be coaxial with the inside rotating body 3 and the outside rotating body 4, a seal ring 1 is formed between the inside rotating body 3 and the shaft body 2a, seals annular passages 8b, 9b being oil passages of the working fluid, and is formed by molding a polyphenylene sulfide resin composition containing an elastomer with a polyphenylene sulfide resin as a main composition. |
