Method and apparatus for the setting of the torque transmitted by a friction clutch

An apparatus for the setting of the torque transmitted by a friction clutch comprising:

• an actuator chain comprising an electric motor, a reduction gear unit and a mechanism for the conversion of the rotary movement of the electric motor into a displacement of a pressure plate of the friction clutch;
• a control unit for the determination of a desired angle of rotation (αDes) of the electric motor or of a link of the actuator chain from the torque to be transmitted by the friction clutch based on a given torque/angle dependence;
• a regulator which acts on the electric motor and by which the desired angle of rotation (αDes) can be set in a setting procedure;
• a sensor for the detection of the current angle of rotation (α);
• a measurement unit for the measurement of the power consumption of the electric motor;
• a calibration unit for the determination of a first correction angle (α′, Δα″) for the torque/angle dependence based on the power consumption measured by the measurement unit, on a given torque/power consumption dependence and on the angle of rotation (αActual) then currently detected by the sensor;
• and
• a correction unit for the taking into account of a variation of the torque/power consumption dependence caused by wear occurring within the actuator chain, wherein the correction unit includes a counter for the determination of the number of setting procedures of the electric motor within a preset time interval and uses the determined number for correcting the torque/power consumption dependence.

A method for setting the torque transmitted by a friction clutch having a moveable pressure plate, comprising:

• providing a clutch actuator mechanism having an electric motor driving a gear unit for controlling operation of a mechanism converting rotary movement of the electric motor into translational movement of the pressure plate;
• determining a desired angle of rotation (αDes) from a desired torque (MDes) to be transmitted by the friction clutch based on a first characteristic representing a given torque/angle dependence;
• determining an actual angle of rotation (αactual);
• generating a control signal for the electric motor based on the difference between the desired and actual angles of rotation for establishing a setting procedure of the electric motor;
• conducting a calibration procedure to compensate for wear in the friction clutch by determining a first correction angle (Δα′) for correcting the first characteristic based on a second characteristic representing a given torque/power consumption dependence;
• and
• conducting a correction procedure to compensate for wear in the clutch actuator mechanism by determining a second correction angle (Δα″) based on variations in the second characteristic.