| 摘要 |
In an aspect, a tensioner includes a shaft and base unit, an arm, a pulley, a spring and a sleeve. The shaft and base unit is stationary. The spring is a helical torsion spring and is positioned to urge the arm in a free arm direction. The arm is urgable by the endless drive member in a load stop direction against urging by the spring. Movement of the arm in the load stop direction causes dimension change in the spring in a first radial direction. The sleeve may be fixed to the arm and engages the spring to limit the dimensional change. The sleeve has a plurality of axially extending ribs extending about its perimeter, which are circumferentially spaced and which simultaneously progressively engage the spring between a first angular position and a second angular position at which the spring is prevented from further movement in the first radial direction. |
