| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic auto tensioner for preventing the excessive tension of a belt. SOLUTION: A sleeve 4 is provided in a cylinder 1 in which operating oil is filled, a rod 5 is slidably inserted at its lower end into the sleeve to form a pressure chamber 6 in the sleeve, and a return spring 8 is incorporated between a spring seat 7 provided at the upper part of the rod and the inner bottom face of the cylinder for energizing the cylinder and the rod in their elongating direction. A check valve 15 is provided in a passage 14 which communicates a reservoir chamber 13 formed between the cylinder and the sleeve with the pressure chamber for closing the passage so that the operating oil in the pressure chamber reduces pushing force on the cylinder and the rod when pushed in their contracting direction. A communication passage 16 is formed in the rod for communicating the pressure chamber with the reservoir chamber, and a relief valve 18 is incorporated in the communication passage. The relief valve keeps fluctuation pressure in the pressure chamber at a constant upper limit value to prevent the excessive tension of the belt whose tension is adjusted with the thrust of the rod. COPYRIGHT: (C)2009,JPO&INPIT |
