| 摘要 |
PROBLEM TO BE SOLVED: To reduce the axial length of a hydraulic automatic tensioner and prevent a deficiency in supply of hydraulic oil by facilitating opening of a valve disc in a high-frequency region so as to prevent a reduction in load of a hydraulic damper. SOLUTION: A sleeve 13 is installed into a cylinder 11 filled with the hydraulic oil, and a flange 14 provided at the lower end of the sleeve is supported by a step part 15 formed at a lower part of the inner periphery of the cylinder. A rod 16 is inserted in the sleeve to partition the inside of the cylinder into a pressure chamber 17 and a reservoir chamber 18. The rod is applied with elastic force of a return spring 21. An arcuate passage 27 serving for communication between the pressure chamber and the reservoir chamber is formed in the flange. The passage is adapted to be opened and closed by the ring-like valve element 28 provided at a lower part of the flange, thereby reducing the axial length of the hydraulic automatic tensioner. The valve disc is adapted to move to an opening position by its own weight when the pressure in the pressure chamber is decreased, so as to prevent a delay in opening of the valve disc in the high-frequency region and also to prevent a reduction in load of the hydraulic damper by the hydraulic oil in the pressure chamber. COPYRIGHT: (C)2008,JPO&INPIT
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