A control apparatus for a four-wheel drive vehicle includes a current detector configured to output a detection signal in accordance with the magnitude of an actual control current, a target current value calculator configured to calculate a target current value that is a target value of the control current, and a current controller configured to control a current output circuit to output the control current having the target current value calculated by the target current value calculator based on a result of detection performed by the current detector. When the four-wheel drive vehicle is in a two-wheel drive mode in which first and second friction clutches are released, the current controller performs zero-point adjustment for adjusting a zero point of the control current to be output from the current output circuit.

A clutch system for a motor vehicle includes a friction clutch and a magnetic clutch. The friction clutch is for transmitting a torque between a torque-introducing element and a torque-discharging element. The magnetic clutch is for actuating the friction clutch. The magnetic clutch includes an open position and a closed position, an axially displaceable permanent magnet, and an electromagnet for axially displacing the permanent magnet between the open position and the closed position of the magnetic clutch. The electromagnet has an activated state and a deactivated state. The permanent magnet is held magnetically fixed in the open position or in the closed position of the magnetic clutch when the electromagnet is in the deactivated state.

A clutch system for a motor vehicle includes a friction clutch and a magnetic clutch. The friction clutch is for transmitting a torque between a torque-introducing element and a torque-discharging element. The magnetic clutch is for actuating the friction clutch. The magnetic clutch includes an open position and a closed position, an axially displaceable permanent magnet, and an electromagnet for axially displacing the permanent magnet between the open position and the closed position of the magnetic clutch. The electromagnet has an activated state and a deactivated state. The permanent magnet is held magnetically fixed in the open position or in the closed position of the magnetic clutch when the electromagnet is in the deactivated state.

A clutch system for coupling a drive shaft of a motor vehicle engine to a transmission input shaft of a motor vehicle transmission is disclosed. The clutch system includes a friction clutch for transmitting a torque between a torque-introducing element and a torque-discharging element. It also includes a ramp system for an axial displacement of a pressure plate of the friction clutch, wherein the ramp system has an input ramp and an output ramp, which can be turned in relation to the input ramp to change an axial extent of the ramp system. A pilot clutch, which acts on the ramp system, is provided for actuating the friction clutch based on a differential speed between the torque-introducing element and the torque-discharging element. An electromagnet for a magnetic actuation of the pilot clutch is further provided, wherein the ramp system is arranged radially within the friction clutch and/or the pilot clutch.

A clutch system for coupling a drive shaft of a motor vehicle engine to a transmission input shaft of a motor vehicle transmission is disclosed. The clutch system includes a friction clutch for transmitting a torque between a torque-introducing element and a torque-discharging element. It also includes a ramp system for an axial displacement of a pressure plate of the friction clutch, wherein the ramp system has an input ramp and an output ramp, which can be turned in relation to the input ramp to change an axial extent of the ramp system. A pilot clutch, which acts on the ramp system, is provided for actuating the friction clutch based on a differential speed between the torque-introducing element and the torque-discharging element. An electromagnet for a magnetic actuation of the pilot clutch is further provided, wherein the ramp system is arranged radially within the friction clutch and/or the pilot clutch.

A driving force transmission control apparatus includes: a driving force transmission device that includes an electromagnetic clutch mechanism configured to generate a frictional force between clutch plates by energization of an electromagnetic coil and transmits a driving force by actuating the electromagnetic clutch mechanism; and a control device that controls the driving force transmission device. The control device includes a storage unit storing a hysteresis value representing the difference between a current value required to transmit a predetermined torque when an energization current to the electromagnetic coil is gradually increased and a current value required to transmit the predetermined torque when the energization current is gradually reduced, a torque command value calculator that calculates a torque command value, and a current command value calculator that calculates a current command value representing a target value of a current to be supplied to the electromagnetic coil based on the torque command value and the hysteresis value.

A driving force transmission control apparatus includes: a driving force transmission device that includes an electromagnetic clutch mechanism configured to generate a frictional force between clutch plates by energization of an electromagnetic coil and transmits a driving force by actuating the electromagnetic clutch mechanism; and a control device that controls the driving force transmission device. The control device includes a storage unit storing a hysteresis value representing the difference between a current value required to transmit a predetermined torque when an energization current to the electromagnetic coil is gradually increased and a current value required to transmit the predetermined torque when the energization current is gradually reduced, a torque command value calculator that calculates a torque command value, and a current command value calculator that calculates a current command value representing a target value of a current to be supplied to the electromagnetic coil based on the torque command value and the hysteresis value.

A control device controls a driving force transmission device that presses a main clutch using an actuator that generates a pressing force according to a supply current. The control device includes a current command value setting unit that sets a current command value based on I-T characteristic information indicating the relationship between a current supplied to the actuator and a driving force transmitted, a correction duration setting unit that sets a correction duration based on a responsiveness related value related to the responsiveness of the main clutch when an increase in the driving force to be transmitted by the main clutch becomes greater than or equal to a threshold, a correction unit that increases and corrects the current command value for the set correction duration, and the current control unit that performs current feedback control such that a current corresponding to the current command value is supplied to the actuator.

A control device controls a driving force transmission device that presses a main clutch using an actuator that generates a pressing force according to a supply current. The control device includes a current command value setting unit that sets a current command value based on I-T characteristic information indicating the relationship between a current supplied to the actuator and a driving force transmitted, a correction duration setting unit that sets a correction duration based on a responsiveness related value related to the responsiveness of the main clutch when an increase in the driving force to be transmitted by the main clutch becomes greater than or equal to a threshold, a correction unit that increases and corrects the current command value for the set correction duration, and the current control unit that performs current feedback control such that a current corresponding to the current command value is supplied to the actuator.

A transfer device of a vehicle is provided, which includes an input shaft for receiving an output torque of a drive source at an axial first side, a main-wheel output part provided on a second side and for outputting the output torque to main drive wheels, an auxiliary-wheel output shaft provided in parallel to the input shaft and for outputting the output torque to auxiliary drive wheels, a coupling provided on the input shaft and for extracting a part of the output torque, a drive member having a hollow section and provided on the input shaft, a driven member provided on the auxiliary-wheel output shaft and meshed with the drive member, a universal joint provided on the auxiliary-wheel output shaft, and a damper device provided on the input shaft or the auxiliary-wheel output shaft and for reducing noise that occurs due to a variation of the output torque.