| 摘要 |
A clutch (18) engaged by means of flyweights (29) and a spring (34) directly meshes an input sun gear (9) and an output planet-wheel carrier (13). If the engagement pressure is insufficient for the torque to be transmitted, the crown wheel (8) slows down and is then stopped by a free wheel (16), while an axial thrust (Pac) produced by the helical teeth releases the clutch (18). The device then functions as a step-down device. To accelerate the procedure, a control unit (152) senses the onset of the slip of the clutch (18) and activates an actuator (44, 46) for releasing the clutch (18) before the forces produced by the teeth occur. In alternative embodiments of the invention, the control unit controls sequential operation forces when two or more clutches must be practically simultaneously actuated. The invention is useful for enhancing the comfort of use and reducing wear and stresses. |
