Servo-assisted control system for the gears of a single clutch gearbox of a motor vehicle

A servo-assisted control system for a single clutch gearbox of a motor vehicle having six or seven forward gears and a reverse gear, the system comprising:

• four actuating forks each of which is associated to one or two gears and has a first engagement member;
• a first hydraulically-operated actuator device for controlling the engagement of all the gears by selection and engagement movements, said first hydraulically-operated actuator device comprising
• a shaft provided with four second engagement members for engagement each with a respective first engagement member of the actuating forks, the shaft being arranged to turn about an axis of the shaft and to translate in the direction of the axis of the shaft;
• a cylinder coaxial to the shaft, the cylinder being arranged only to translate in a direction of an axis of the cylinder;
• and
• a pin drivingly connected either to the shaft or to the cylinder and engaging in an S-shape groove provided either in the cylinder or in the shaft, respectively, so as to link the rotational and translational movements of the shaft with the translational movement of the cylinder;
• and
• a second hydraulically-operated actuator device arranged to lock or release selectively the translational movement of the cylinder of the first hydraulically-operated actuator device.