A driving force distribution control device mounted on a four-wheel drive vehicle is provided. A coupling mechanism controller connects a drive shaft with an auxiliary driving wheel and sets a fastening force as a first fastening force, when an increase rate in an accelerator opening becomes more than a given value and a vehicle speed is below a given first speed, and changes the fastening force from the first fastening force to a second fastening force, when a slip of at least one of main driving wheels is detected after the fastening force is set to the first fastening force, and before a given time period has lapsed from the setting of the fastening force, or before the vehicle speed becomes faster than a given second speed. The second fastening force at least immediately after the change of the fastening force is a value larger than the first fastening force.

The invention relates to an electrically driven clutch actuators (1) for actuating the clutch of a transmission of a vehicle. An actuator comprises a spindle nut (11) on a spindle (9) and a pressure piece (13) displaceable relative to the spindle nut (11) and coupled to the spindle nut by a biasing spring (15). By rotation of the threaded spindle under a driving force of an electric motor (5), the spindle nut (11) compresses the biasing spring (15) and displaces the pressure piece (13) to disengage the clutch. A latching mechanism (16) is configured to limit displacement of the spindle nut away from the pressure piece under the force of the expanding biasing spring when the driving force is reduced below a predetermined level. Further, a control unit is described that reduces the driving force in response to a trigger condition to reduce power consumption in the clutch disengaged state.

A friction engagement element control system is provided, which includes a friction engagement element including friction plates, which are an input-side friction plate and an output-side friction plate, and an actuation system configured to engage the input-side friction plate with the output-side friction plate with a pushing force, the friction plates having a characteristic in which a friction coefficient thereof decreases as a rotational difference between the friction plates increases. The device includes a controller configured to control the pushing force so that the negative slope characteristic becomes a positive slope characteristic in which a frictional force of the friction engagement element decreases as the rotational difference decreases, when engaging the friction engagement element.

A friction engagement element control system is provided, which includes a friction engagement element including friction plates, and an actuation system configured to engage an input-side friction plate with an output-side friction plate with a pushing force, the friction plates having a negative slope characteristic in which a friction coefficient thereof decreases as a rotational difference between the friction plates increases, a rotational difference sensor of the friction engagement element, a separator configured to divide a variation in the detected rotational difference into a high-frequency component that is a vibration component and other low-frequency components, and a controller configured to control a pushing force only for the vibration component of the rotational difference so that the negative slope characteristic becomes a positive slope characteristic in which a frictional force of the friction engagement element decreases as the rotational difference decreases, when engaging the friction engagement element.

A vehicle drive device includes: an electric motor; a multi-plate clutch including a plurality of clutch plates; a pressing mechanism configured to press the multi-plate clutch; an output rotary member to which a drive force of the electric motor is transferred through the multi-plate clutch; and a control device configured to control the electric motor and the pressing mechanism. The control device is configured to control the pressing mechanism using information on the result of test operation performed while the vehicle is stationary.

Controlling a multiplate clutch situated between an input shaft and an output shaft for the switchable transmission of torques, wherein in the event of a torque request and a subsequent engagement of the multiplate clutch, includes: a) determining a setpoint engagement force, acting in an axial direction, of the multiplate clutch for transmitting a setpoint torque to the output shaft; b) determining and setting a limiting engagement force that is less than the setpoint engagement force, and c) setting the setpoint engagement force in a time-delayed manner;
wherein a transmission of an actual torque is achieved by limiting the setpoint engagement force to the limiting engagement force, so that a maximum actual torque that is transmitted upon engagement of the multiplate clutch exceeds a setpoint torque to be transmitted by at most 5%.

A driving force distribution control device mounted on a four-wheel drive vehicle is provided. A coupling mechanism controller connects a drive shaft with an auxiliary driving wheel and sets a fastening force as a first fastening force, when an increase rate in an accelerator opening becomes more than a given value and a vehicle speed is below a given first speed, and changes the fastening force from the first fastening force to a second fastening force, when a slip of at least one of main driving wheels is detected after the fastening force is set to the first fastening force, and before a given time period has lapsed from the setting of the fastening force, or before the vehicle speed becomes faster than a given second speed. The second fastening force at least immediately after the change of the fastening force is a value larger than the first fastening force.

A control system in a four-wheel-drive motor vehicle for the distribution of drive forces at least from a drive of the motor vehicle to wheels of the first and second axles of the motor vehicle, at least including:

a distribution device for distributing the drive forces to the first and second axles; rotation rate sensors for detecting the rotation rate of the two axles and/or the wheels of the motor vehicle, a central control device that is connected to a distribution controller and the sensors and a vehicle communication system, wherein the distribution controller is attached to the distribution unit and performs control both to a setpoint torque and to a setpoint rotation rate, and thusin a drive-dependent and switchable mannerdetermines a distribution ratio of the drive forces to be distributed to the first and second axles on the basis of the ratio between the torque and the setpoint torque or between the setpoint rotation rate and the setpoint rotation rate.

A four-wheel-drive vehicle includes: a pump that is actuated by an electric motor; a friction clutch that has a plurality of clutch plates that are pressed by a piston that is movable by working oil discharged from the pump; a control device that controls the electric motor; front wheels, to which a drive force of an engine is always transferred; and rear wheels, to which the drive force of the engine is transferred in accordance with the fastening force of the friction clutch. When it is determined that the vehicle is in a high fastening force-requiring state in which it is necessary for the friction clutch to transfer a large drive force temporarily, the control device causes the electric motor to output torque that is larger than torque that the electric motor can continuously output.

Controlling a multiplate clutch situated between an input shaft and an output shaft for the switchable transmission of torques, wherein in the event of a torque request and a subsequent engagement of the multiplate clutch, includes: a) determining a setpoint engagement force, acting in an axial direction, of the multiplate clutch for transmitting a setpoint torque to the output shaft; b) determining and setting a limiting engagement force that is less than the setpoint engagement force, and c) setting the setpoint engagement force in a time-delayed manner;

wherein a transmission of an actual torque is achieved by limiting the setpoint engagement force to the limiting engagement force, so that a maximum actual torque that is transmitted upon engagement of the multiplate clutch exceeds a setpoint torque to be transmitted by at most 5%.