A sequential gear control device for a motor-vehicle gearbox comprising a pair of rotary drums

摘要

The gear control device (100) comprises a first drum (10) and a second drum (16) each rotatable about a respective rotation axis (X1, X2) and an actuation unit (42, 44, 46, 48) arranged to bring about rotation of the first and second drums (10, 16) in a synchronized manner about the respective rotation axes. Each of the first and second drums (10, 16) has, on its outer cylindrical surface, at least one guide channel (22, 26) in which at least one follower member (24, 28) is intended to be guided slidably to convert the rotary movement of the drum (10, 16) about its own rotation axis (X1, X2) into translatory movement of at least one engagement sleeve of the gearbox. A series of positioning notches (50) are provided on the outer cylindrical surface of the first drum (10) only and are spaced apart angularly along a circumference of the first drum (50) for snap-engagement by a stop member (54, 56) of the gear control device (100) associated with the first drum (10).