| 摘要 |
A gear change (1) for a commercial vehicle comprising a main group (35) defining a plurality of transmission ratios and an auxiliary group (34) with two transmission ratios actuated by an actuator (37) with three positions corresponding respectively to two coupling positions and one neutral position; the actuator (37) is controlled by a control unit (47) in response to actuating signals (ss,sr) received by manual selectors (56,57), and it is adapted to place the auxiliary group (34) in the neutral position if the speed of rotation of the input shaft (2) exceeds a predetermined threshold value (sT). <IMAGE> |
