Timing belt tensioner with damped constant spring tensioning and belt tooth disengagement prevention.

摘要

A timing belt tension device (28) comprises a fixed structure (30) having a spring pressed pivoted structure (34) mounted thereon for pivotal movement about a first axis between first and second limiting positions. The pivoted structure carries a timing belt engaging pulley (36) for rotational movement about a second axis parallel with the first axis. A one-way clutch mechanism (40) is provided for permitting pivotal movement of the pivoted structure in a direction toward a second limiting position and for limiting the pivotal movement of the pivoted structure in an opposite direction toward the first limiting position beyond a predetermined distance measured from the nearest position of the pivoted structure to the second limiting position. The predetermined distance has a maximum dimension such as to prevent loosening of the timing belt (12) engaged by the pulley sufficient to allow disengagement of a tooth (14) thereof with a tooth (18 or 24) of a timing pulley (16 or 22) and a minimum dimension such as to accommodate normal operating low amplitude movements and thermal expansion during operation. A damping system (42) is provided for damping the operating movements of the pivoted structure permitted by the one-way clutch mechanism (40).