Automobile gearbox and ratio change method for such a gearbox

摘要

The box has a synchronizer (18) for synchronizing a reverse gear (10) and a shaft (8). A speed sensor (28) measures a magnitude representing a rotational speed of a primary shaft (2), and a parameter input (30) inputs a parameter representing the rotational speed of a secondary shaft (4). A control unit (32) controls the box informed by a speed sensor and by the input (30) and receives the orders from a control block (26). The unit (32) controls the synchronization of the gear with the shaft (8) until the synchronizer indicates that more elevated gear ratio is attained. An independent claim is also included for a method for changing the gear ratio of a gearbox.