| 摘要 |
PROBLEM TO BE SOLVED: To improve reliability of operation with respect to minute fluctuation of tension of a belt in regard to an automatic tensioner which blocks movement of a rod by an external signal. SOLUTION: A piston 12 formed on the rod 11 is slidably inserted in a sleeve 9 fixed in a cylinder 10. A pressure chamber 14 in the sleeve 9 is filled with operating fluid. The operating fluid is stored in a reservoir chamber 15 between the cylinder 10 and the sleeve 9. A first passage 18 is provided for communicating the pressure chamber 14 with the reservoir chamber 15. A first check valve 19 is provided in the first passage 18 for allowing a flow of the operating fluid only from a reservoir chamber 15 side to a pressure chamber 14 side. A second chamber 20 is provided for communicating the pressure chamber 14 with the reservoir chamber 15. A second check valve 21 is provided in the second passage 20 for allowing a flow of the operating fluid only from the pressure chamber 14 side to the reservoir 15 side. A solenoid valve 22 for opening and closing the second passage 20 is provided between the second check valve 21 and the reservoir chamber 15, and a restrictor 23 is provided in the second chamber 20. A composition is adopted for energizing the rod 11 and the cylinder 10 by a return spring 17 in a direction for increasing the volume of the pressure chamber 14. COPYRIGHT: (C)2007,JPO&INPIT
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