Under travel actuator, particularly for automobile clutch

A travel compensation actuator for a clutch of a motor vehicle, comprising:

• a casing;
• a driving mechanism (16);
• a motor (12) mounted to the casing for driving the driving mechanism along an outward and a return path;
• and
• travel compensating means 14 for compensating travel of the driving mechanism and connecting the motor (12) to the driving mechanism (16);
• the travel compensating means (14) mounted to the casing (10) and displaceable inside the casing by the motor along an adjustment path (P0-P2) and along a drive path (P3-P4) of the driving mechanism (16);
• the travel compensating means comprising a slide element (18) displaceable within the casing (10) and driven by the motor (12) along the adjustment and drive paths, means (22, 24) for adjusting the position of a drive stop of the driving mechanism and two combined means (34a, 34b) for unidirectional travel of the drive stop;
• the position adjustment means including a screw (22) defining the drive stop and a nut (24) screwed onto the screw (22) both mounted inside the casing (10);
• the two combined unidirectional travel means (34a, 34b) are mounted inside the casing (10) to cooperate with the position adjustment means (22, 24) in order to displace the position adjustment means (22, 24) by one step in one direction or the other when the travel compensating means (14) are displaced by the motor in one direction or the other from an intermediary position (P1) of the adjustment path;
• the position adjustment means (22, 24) mounted to the slide member (18) such that the screw (22) being linearly displaceable and non-rotatable in the slide member (18);
• the nut (24) being rotatable on the slide member and comprising an external teeth (30) cooperating with the two combined unidirectional travel means (34a, 34b) when the slide member (18) travels along the adjustment path;
• the combined unidirectional travel means comprising two unidirectional drive rings (34a, 34b) mounted in a rotational manner around the slide member (18) and having an internal teeth (32) intended to work in cooperating with the external teeth (30) of the nut (24), the two unidirectional drive rings engaging elastic means of return (40)3 inducing the two unidirectional drive rings to rotate in opposite directions until the two unidirectional drive rings come to rest against stops formed on the slide member (18).