| 摘要 |
<p>A pulley unit, in particular for an internal combustion engine, comprises a hub (3) for a driving shaft, a ring-shaped element (5) externally coaxial to the hub (3) and having a seat for the engagement by a belt, and a connection device (14, 15) interposed between the hub (3) and the ring-shaped element (5). The connection device (14, 15) is adapted to undergo elastic deformations in consequence of the tendency of the hub (3) to assume a speed different from that one of the ring-shaped element (5), in order to carry out the function of a flexible coupling at least for small variations of said speed difference. The connection device (14, 15) has a behaviour different depending on the tendency of the hub (3) to rotate faster or slower than the ring-shaped element (5). When the tendency of the hub (3) to rotate faster than the ring-shaped element (5) increases, the device assumes the behaviour of a flexible coupling with increasing stiffness, while in the opposite case the connection device tends to uncouple the hub (3) from the ring-shaped element (5). <IMAGE></p> |
