A hydrostatic actuator system includes an electric motor for delivering a hydraulic fluid via a piston unit. The actuator system is operating using a method in which a change in volume caused by a temperature change is sensed by a pressure measurement. The method reliably identifies a state of the transfer of the hydraulic fluid from a planetary roller transmission compartment into the master piston. The pressure measurement is continuously evaluated, and, in the event of a negative signal of the pressure measurement, suction of the hydraulic fluid by a planetary roller transmission lying in the hydraulic fluid between the electric motor and the piston unit into the piston unit is recognized and a fault signal is output.

A method determines the travel of a clutch in a hydraulic clutch-actuation system. A hydraulic signal which extends between a transmitting end and a receiving end is acted upon by an acoustic signal for the generation of a wave packet. The acoustic signal on the transmitting end of the clutch-actuation system is fed into the hydraulic fluid, a wave packet generated by the acoustic signal on the receiving end is reflected back to the transmitting end, a running time of the transmitted and reflected wave packet on the transmitting end is evaluated to determine the coupling travel.

This vehicle transmission system includes a transmission (21), a clutch device (26), a clutch control unit (61), and a shift operation detecting means (48), and, when a hydraulic pressure is supplied from a clutch actuator (50) to a slave cylinder (28), the clutch device (26) moves to a connection side, in an in-gear stop state in which the transmission (21) is in an in-gear state, and a vehicle (1) is in a stop state, the clutch actuator (50) supplies a standby hydraulic pressure (WP) to the slave cylinder (28), and the clutch control unit (61) sets the standby hydraulic pressure (WP) to a first setting value (P1) during non-detection in which a shift operation is not detected by the shift operation detecting means (48) and sets the standby hydraulic pressure (WP) to a second setting value (P2) lower than the first setting value (P1) when the shift operation is detected by the shift operation detecting means (48).

Disclosed is a clutch control reference value setting method including generating a current-hydraulic pressure model, setting a temporary VKP to a current causing a maximum difference between a model hydraulic pressure and a measured hydraulic pressure, determining that the temporary VKP is valid when a deflection amount calculated from a difference integral value acquired by integrating differences between the model hydraulic pressure and the measured hydraulic pressure while increasing the current is greater than a first reference value under a condition that the first target pressure is applied to the clutch, determining that the temporary VKP is appropriate when a deflection amount calculated from a difference integral value acquired by integrating differences between the model hydraulic pressure and the measured hydraulic pressure while increasing the current is proper under a condition that a second target pressure is applied to the clutch.

This vehicle transmission system includes a transmission (21), a clutch device (26), a clutch control unit (61), and a shift operation detecting means (48), and, when a hydraulic pressure is supplied from a clutch actuator (50) to a slave cylinder (28), the clutch device (26) moves to a connection side, in an in-gear stop state in which the transmission (21) is in an in-gear state, and a vehicle (1) is in a stop state, the clutch actuator (50) supplies a standby hydraulic pressure (WP) to the slave cylinder (28), and the clutch control unit (61) sets the standby hydraulic pressure (WP) to a first setting value (P1) during non-detection in which a shift operation is not detected by the shift operation detecting means (48) and sets the standby hydraulic pressure (WP) to a second setting value (P2) lower than the first setting value (P1) when the shift operation is detected by the shift operation detecting means (48).

A clutch connecting/disconnecting device comprises: a clutch pedal; a clutch cylinder; a depression force transmission mechanism; and an actuator. The depression force transmission mechanism is configured to include a cylinder device. The cylinder device includes an input piston, an output piston, a first oil chamber, and a second oil chamber. A pressure receiving area on the first oil chamber side of the output piston is made equal to a pressure receiving area on the second oil chamber side of the output piston. The first oil chamber and the second oil chamber are connected via an electromagnetic valve connecting and disconnecting between the first oil chamber and the second oil chamber, and the actuator is connected to the output piston in a power transmitting manner.

Disclosed is a clutch control reference value setting method including generating a current-hydraulic pressure model, setting a temporary VKP to a current causing a maximum difference between a model hydraulic pressure and a measured hydraulic pressure, determining that the temporary VKP is valid when a deflection amount calculated from a difference integral value acquired by integrating differences between the model hydraulic pressure and the measured hydraulic pressure while increasing the current is greater than a first reference value under a condition that the first target pressure is applied to the clutch, determining that the temporary VKP is appropriate when a deflection amount calculated from a difference integral value acquired by integrating differences between the model hydraulic pressure and the measured hydraulic pressure while increasing the current is proper under a condition that a second target pressure is applied to the clutch.

Setting a system pressure for a hydraulically actuated clutch comprises

a) Providing a system comprising a pump drivable by an electrically operated motor controlled by a control unit that senses a motor current and rotational speed and a system temperature is determined;

b) a characteristic diagram is provided specifying values for at least the motor current and rotational speed for different system operating points;

c) Accessing the characteristic diagram while operating a vehicle;

d) Sensing at least the motor current and rotational speed at at least a first operating point and determining the system temperature ;

e) Comparing the values, acquired in step d) for the current and speed with the values for the current and rotational speed from the characteristic diagram according to step b);

f) Adapting the characteristic diagram for the system on the basis of the parameters determined in step d).

A vehicle drive train, has a clutch unit actuatable by an actuating unit, and a sensor for determining the coupling status. The actuating unit includes an electromagnetic actuator having a piston movable from a starting to an end position. At least the piston and the clutch are acted on by a transmission fluid. Operating the drive train can include: a) actuating the actuator and moving the piston from the starting position; b) ascertaining a measured sensor value; c) ascertaining a temperature of the transmission fluid by measuring an electrical resistance of the actuator and/or measuring a first time interval between actuation of the actuator according to step a) and the detection by the sensor of an intermediate position that is reached by the piston; d) determining an actual position of the piston based on the measured sensor value and the temperature; and e) moving the piston, starting from the determined actual position, into the end position.

The invention relates to a method for determining the absolute position of a component of an actuator rotating about a rotational axis, in particular a clutch actuator, wherein the component has a co-rotating magnetic element (18), and the absolute position of the magnetic element (18) is detected by way of a multi-turn sensor (16) located opposite the magnetic element (18), which is supplied with a voltage. In a method, in which the absolute position can be detected without great constructional effort, a position of the magnetic element (18) is monitored by a Wiegand wire unit (19), which detects a movement of the component when the actuator (3, 12, 13) is turned off, and if a movement is detected, transmits a voltage pulse to the multi-turn sensor (16) for measuring the current position of the component.