| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a hydraulic auto tensioner which can impart proper tension to a belt at a normal operation of an engine and a start of the engine by a starter generator.SOLUTION: A male screw 30 is arranged at an external periphery of a lower end of a rod 16, and a nut member 31 engaged with the male screw 30 is rotatably supported into a cylinder 10 and regulated in movement in the axial direction. The male screw 30 and a female screw 32 of the nut member 31 are formed into serration shapes in which flank angles of pressure-side flanks are larger than flank angles of loosening-side flanks, and the serration-shaped screws are set in a loosening condition that the nut member 31 rotates against a load of an elastic force by which a return spring 20 presses the cylinder 10 and the rod 16 to extension directions, and in a lock condition that the rotation of the nut member 31 is prohibited against a load of an abrupt press-in force which contracts the cylinder 10 and the rod 16.</p> |
