| 摘要 |
A hydraulic auto-tensioner is proposed which is free of deterioration in hydraulic damping function and which can sufficiently quickly generate hydraulic damping force. The auto-tensioner includes a sleeve (4) having its bottom end press-fitted in a sleeve fitting hole (3) formed in the bottom surface of a cylinder (1), a rod (5) having its bottom end slidably fitted in the sleeve (4), and a return spring (8) mounted between a spring support (7) provided at the upper portion of the rod (5) and the bottom surface of the cylinder (1). A passage (14) is formed between fitting surfaces of the sleeve fitting hole (3) and the sleeve (4) through which a pressure chamber (6) communicates with a reservoir chamber (13). A check valve (15) is mounted in the passage (14). The rod (5) is formed with a valve fitting hole (16) and a communication passage (17) through which the valve fitting hole (16) communicates with the reservoir chamber (13). A relief valve (20) is mounted in the valve fitting hole (16). An orifice (27) is formed between a valve hole (22) formed in a valve seat (21) of the relief valve (20) and a valve body (23) to prevent a sharp drop in pressure in the pressure chamber (6). |
