| 摘要 |
PROBLEM TO BE SOLVED: To release a damper action of an automatic tensioner, and to facilitate the releasing operation. SOLUTION: In this automatic tensioner 5, a sleeve 8 is fitted in a cylinder 7, a plunger 10 is slidably inserted into the sleeve 8 to partition the inside of the cylinder 7 into a pressure chamber 11 and a reservoir chamber 12, a rod 16 moving integrally with the plunger 10 is provided, and a return spring 19 energizing the rod 16 in a direction projecting from the cylinder 7 is provided. In the automatic tensioner 5, a through hole 23 is formed at a bottom 9 of the sleeve 8, a bypass passage 24 communicating the through hole 23 with the reservoir chamber 12 is formed, radial direction grooves 25 and 26 extending from the through hole 23 are provided at an inner bottom surface of the sleeve 8, the through hole 23 and the radial direction grooves 25 and 26 are covered with a valve element 27 provided to be overlapped with the inner bottom surface of the sleeve 8, a through hole 28 is formed in the valve element 27, and a rotary shaft 30 rotating and operating the valve element 27 is provided between a position where the through hole 28 is communicated with the radial direction grooves 25 and 26 and a position where the communication is not performed. COPYRIGHT: (C)2009,JPO&INPIT
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