| 摘要 |
PROBLEM TO BE SOLVED: To change, in a hydraulic auto tensioner for applying a tension to a belt of a belt transmission device for use in an internal combustion engine, the damping force in compression of the tensioner in two stages according to the magnitude of rotational fluctuation of an engine without perfectly locking a flow passage in spite of use of general oil. SOLUTION: A plunger attached to an upper mounting member is slidably fitted to a cylinder attached to a lower mounting member, a reservoir chamber is formed between these members and a housing covering them, and a coil spring is provided to bias the plunger and the cylinder in a mutually separating direction. A check valve which allows passing of only oil from the reservoir chamber into the cylinder is provided at a lower portion of the cylinder, and a high pressure oil chamber is formed within the cylinder. A first throttle is formed in a return oil passage connecting the high pressure oil chamber to the reservoir chamber through the inside of the plunger and the inside of the mounting members, a solenoid valve is provided serially to the first throttle, and a second throttle is formed on or in the vicinity of the solenoid valve serially to the first valve. COPYRIGHT: (C)2011,JPO&INPIT
|
