| 摘要 |
PROBLEM TO BE SOLVED: To provide an automatic tensioner capable of preventing hydraulic oil in a reservoir chamber from easily leaking to the outside of a cylinder, and excelling in reliability over a long time. SOLUTION: This automatic tensioner is structured such that hydraulic oil is sealed in the cylinder by arranging oil seals 15 and 16 at an open-side end of the cylinder 10; a sleeve 13 is arranged in the cylinder; the inside of the cylinder is divided into a pressure chamber 18 and the reservoir chamber 19 by a plunger 17 slidably inserted into the sleeve; a leak space communicating with the pressure chamber and the reservoir chamber is formed between the plunger and the sliding surface of the sleeve; a passage 36 for making the pressure chamber communicate with the reservoir chamber, and a check valve 37 are formed in the plunger; a rod 20 axially moving integrally with the plunger is arranged; the rod is made to slidably penetrate the oil seals; and a return spring 22 energizing the rod is arranged. In the automatic tensioner, the hydraulic oil is prevented from leaking by providing the oil seals with a pressure-side lip receiving pressure in the reservoir chamber, and a non-pressure-side lip without receiving the pressure in the reservoir chamber. COPYRIGHT: (C)2008,JPO&INPIT
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