Under travel actuator, particularly for an automobile clutch

Travel compensation actuator, in particular for a motor vehicle, comprising a driving mechanism (16) and a motor (12) driving the driving mechanism along an outward and a return path, further comprising means (14) for compensating travel which connect the motor (12) to the drive mechanism (16) and which can be displaced by said motor along an adjustment path (P0-P2) and along a drive path (P3-P4) of the driving mechanism (16), said compensating means comprising means (22, 24) for adjusting the position of a drive stop of the driving mechanism and two combined means (34a, 34b) for unidirectional travel which are mounted on the casing (10) of the actuator and which operate in conjunction with the means of adjustment in order to rotate them by one turn in one direction or the other when the compensating means (14) are displaced by the motor in one direction or the other from an intermediary position (P1) of their adjustment course, with said compensating means (14) comprising a slide element (18), which is displaced within the casing (10) of the actuator and driven by the motor (12) along said adjustment and drive paths, and a screw-nut system (22, 24) mounted on the slide member (18), in which the screw (22) constituting the drive stop of the driving mechanism (16) and being displaced and arrested in rotation in the slide member (18), the nut (24) being screwed onto the screw, rotated on the slide member and comprising an outer toothing (30) that works in conjunction with the two combined means of unidirectional travel (34a, 34b) when the slide member (18) travels along said adjustment path.