| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic auto tensioner using a bellows and having improved durability. SOLUTION: A sleeve 4 is provided in a cylinder 1 in which operating oil is filled, a pressure chamber 6 is formed in the sleeve by slidably inserting the lower end of a rod 5 into the sleeve, and a return spring 8 is incorporated between a spring seat 7 provided at the upper part of the rod 5 and the inner bottom face of the cylinder for energizing the cylinder and the rod in the elongating direction. The expansive bellows 11 is mounted between the outer periphery of the spring seat and the upper part of the cylinder to form a reservoir chamber 23 between the cylinder and the sleeve, and a check valve 25 is provided in a passage 24 making the reservoir chamber communicate with the pressure chamber. When the cylinder and the rod are pushed in the shrinking direction, the check valve closes the passage and operating oil in the pressure chamber alleviates the pushing force. The bellows is formed in a bellows shape, and a shape retaining ring 17 is embedded in an outer gathered portion 15 and an inner gathered portion 16 of the bellows 12 for preventing the deformation and breakage of the bellows in the radial direction when the bellows is expanded. COPYRIGHT: (C)2009,JPO&INPIT
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