Abstract: A drive force transmission apparatus is mountable on a four-wheel drive vehicle switchable between a four-wheel drive mode that transmits a drive force of an engine to front wheels and rear wheels, and a two-wheel drive mode that transmits the drive force to only the front wheels. The drive force transmission apparatus allows adjustment of the drive force to the rear wheels, and includes a multi-plate clutch, a piston for axially pressing the multi-plate clutch, an actuator for axially moving the piston, and a control unit for controlling the actuator. Upon satisfaction of a predetermined condition that indicates a high probability of the vehicle needing to be switched from the two-wheel drive mode to the four-wheel drive mode, the control unit causes the actuator to displace the piston by a predetermined amount with respect to an initial position of the piston toward the multi-plate clutch.

Abstract: An apparatus for controlling a four-wheel drive vehicle includes a tire friction circle calculator that calculates the size of a tire friction circle of each wheel on the basis of vehicle information including a tire vertical load, a resultant force calculator that calculates the magnitude of a resultant force of tire lateral and longitudinal forces for each wheel, a tire-friction-force usage rate calculator that calculates a tire-friction-force usage rate of each wheel that is the ratio of the magnitude of the resultant force to the size of the tire friction circle, and a driving-braking force adjustment controller that adjusts driving force or braking force applied to each wheel.

Abstract: 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.

Abstract: An apparatus for controlling a four-wheel drive vehicle includes a tire friction circle calculator that calculates the size of a tire friction circle of each wheel on the basis of vehicle information including a tire vertical load, a resultant force calculator that calculates the magnitude of a resultant force of tire lateral and longitudinal forces for each wheel, a tire-friction-force usage rate calculator that calculates a tire-friction-force usage rate of each wheel that is the ratio of the magnitude of the resultant force to the size of the tire friction circle, and a driving-braking force adjustment controller that adjusts driving force or braking force applied to each wheel.

Abstract: In a four-wheel-drive vehicle, a hydraulic unit has an electric motor, to which a motor current is supplied from a control device, and a pump that is actuated by rotation of a motor shaft, and a drive force transfer device has a piston that is moved by the pressure of working oil discharged from the pump, and a friction clutch that is switchable between a transfer state and a blocked state, in which transfer of a drive force to rear wheels is allowed and blocked, respectively, in accordance with movement of the piston. The control device detects the presence or absence of an abnormality of a flow passage forming member, which forms a flow passage for working oil, in accordance with at least any of a motor current and the number of revolutions of a motor shaft at the time when the motor shaft is rotated by applying a voltage to the electric motor.

Abstract: A clutch apparatus includes a clutch hub, a clutch drum, a multi-plate clutch having inner clutch plates and outer clutch plates, a piston for pressing the multi-plate clutch, an electric motor, a moving mechanism for moving the piston in an axial direction in accordance with the amount of rotation of the electric motor, and a control unit for controlling the electric motor. When increasing a rotational force that is transmitted between the clutch hub and the clutch drum by increasing electric current that is supplied to the electric motor, the control unit moves the piston in the axial direction by temporarily supplying the electric motor with the electric current having a first current value that is greater than a second current value corresponding to a target rotational force that needs to be transmitted between the clutch hub and the clutch drum.

Abstract: A driving-force transmitting apparatus includes first and second friction clutches, a piston that presses the first and second friction clutches, a hydraulic pump that feeds hydraulic oil to a cylinder chamber in the piston, an electric motor that drives the hydraulic pump, and a control apparatus that controls the electric motor to adjust the discharge pressure of the hydraulic pump. The control apparatus has a feedback control apparatus that controls the electric motor using a correction value based on a deviation between a target value and an actual value of the discharge pressure of the hydraulic pump, a hydraulic-oil temperature estimating apparatus that estimates a temperature of hydraulic oil, and a gain adjusting apparatus that changes a correction amount for feedback control in accordance with the estimated temperature of the hydraulic oil.

Abstract: 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.

Abstract: A control apparatus controls a driving force transmission device including: an electric motor; a pressing mechanism to convert the rotational force of the motor into an axial pressing force; friction clutches including friction members configured to come into frictional engagement with each other by the pressing force provided by the pressing mechanism. The driving force transmission device is configured to transmit a driving force between a pair of rotary members by the friction clutches. The apparatus includes: a target current calculating circuit to calculate a target current to be supplied to the motor; and a correction circuit to correct a voltage to be applied to the motor so as to reduce a difference between the target current and an actual current supplied to the motor. The correction circuit increases or reduces, in accordance with the actual current, the amount of correction of the voltage to be applied to the motor.

Abstract: 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.

Abstract: In a four-wheel-drive vehicle, a hydraulic unit has an electric motor, to which a motor current is supplied from a control device, and a pump that is actuated by rotation of a motor shaft, and a drive force transfer device has a piston that is moved by the pressure of working oil discharged from the pump, and a friction clutch that is switchable between a transfer state and a blocked state, in which transfer of a drive force to rear wheels is allowed and blocked, respectively, in accordance with movement of the piston. The control device detects the presence or absence of an abnormality of a flow passage forming member, which forms a flow passage for working oil, in accordance with at least any of a motor current and the number of revolutions of a motor shaft at the time when the motor shaft is rotated by applying a voltage to the electric motor.

Abstract: A drive force transmission apparatus is mountable on a four-wheel drive vehicle switchable between a four-wheel drive mode that transmits a drive force of an engine to front wheels and rear wheels, and a two-wheel drive mode that transmits the drive force to only the front wheels. The drive force transmission apparatus allows adjustment of the drive force to the rear wheels, and includes a multi-plate clutch, a piston for axially pressing the multi-plate clutch, an actuator for axially moving the piston, and a control unit for controlling the actuator. Upon satisfaction of a predetermined condition that indicates a high probability of the vehicle needing to be switched from the two-wheel drive mode to the four-wheel drive mode, the control unit causes the actuator to displace the piston by a predetermined amount with respect to an initial position of the piston toward the multi-plate clutch.

Abstract: A clutch apparatus includes a clutch hub, a clutch drum, a multi-plate clutch having inner clutch plates and outer clutch plates, a piston for pressing the multi-plate clutch, an electric motor, a moving mechanism for moving the piston in an axial direction in accordance with the amount of rotation of the electric motor, and a control unit for controlling the electric motor. When increasing a rotational force that is transmitted between the clutch hub and the clutch drum by increasing electric current that is supplied to the electric motor, the control unit moves the piston in the axial direction by temporarily supplying the electric motor with the electric current having a first current value that is greater than a second current value corresponding to a target rotational force that needs to be transmitted between the clutch hub and the clutch drum.

Abstract: 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.

Abstract: Provided is a control device for a four-wheel drive which can maintain driving stability while restraining noise and vibration. A control device includes: a second control device that, when at least one of front wheel has slipped, engages a dog clutch after rotating a propeller shaft by a rotational force transmitted via first and second friction clutches; and a third control device that, if a predetermined condition is satisfied when the front wheels are not slipping, engages the dog clutch after rotating the propeller shaft by the rotational force transmitted via the first and second friction clutches. The time required to synchronize the dog clutch by the third control device is longer than that required to synchronize the dog clutch by the second control device.

Abstract: A control apparatus controls a driving force transmission device including: an electric motor; a pressing mechanism to convert the rotational force of the motor into an axial pressing force; friction clutches including friction members configured to come into frictional engagement with each other by the pressing force provided by the pressing mechanism. The driving force transmission device is configured to transmit a driving force between a pair of rotary members by the friction clutches. The apparatus includes: a target current calculating circuit to calculate a target current to be supplied to the motor, and a correction circuit to correct a voltage to be applied to the motor so as to reduce a difference between the target current and an actual current supplied to the motor. The correction circuit increases or reduces, in accordance with the actual current, the amount of correction of the voltage to be applied to the motor.

Abstract: A driving-force transmitting apparatus 1 includes first and second friction clutches, a piston that presses the first and second friction clutches, a hydraulic pump that feeds hydraulic oil to a cylinder chamber in the piston, an electric motor that drives the hydraulic pump, and a control apparatus that controls the electric motor to adjust the discharge pressure of the hydraulic pump. The control apparatus has a feedback control apparatus that controls the electric motor using a correction value based on a deviation between a target value and an actual value of the discharge pressure of the hydraulic pump, a hydraulic-oil temperature estimating apparatus that estimates a temperature of hydraulic oil, and a gain adjusting apparatus that changes a correction amount for feedback control in accordance with the estimated temperature of the hydraulic oil.

Abstract: Provided is a control device for a four-wheel drive which can maintain driving stability while restraining noise and vibration. A control device includes: a second control device that, when at least one of front wheel has slipped, engages a dog clutch after rotating a propeller shaft by a rotational force transmitted via first and second friction clutches; and a third control device that, if a predetermined condition is satisfied when the front wheels are not slipping, engages the dog clutch after rotating the propeller shaft by the rotational force transmitted via the first and second friction clutches. The time required to synchronize the dog clutch by the third control device is longer than that required to synchronize the dog clutch by the second control device.

Abstract: When a vehicle speed is equal to or higher than a first vehicle speed threshold value or an uphill gradient is lower than a first gradient threshold value and uphill start control is cancelled, if a state where the vehicle speed is lower than a second vehicle speed threshold value and the uphill gradient is equal to or higher than a second gradient threshold value continues for a first set time, uphill start control is executed. When the vehicle speed is decreased after being once increased within a range where the vehicle speed is lower than the first vehicle speed threshold value and uphill start control is cancelled, if a state where the vehicle speed is lower than the second vehicle speed threshold value and the uphill gradient is equal to or higher than the second gradient threshold value continues for a second set time, the uphill start control is executed.

Abstract: Discloses is a method of controlling a four-wheel drive vehicle equipped with a torque distribution device capable of changing a torque distribution amount for secondary driven wheels according to an input current to be applied thereto. This method comprises the steps of: applying, to the torque distribution device, a current value corresponding to a target torque distribution amount; and, performing a current changing control for increasing and reducing the input current to the torque distribution device. The step of performing a current changing control includes causing the input current to the torque distribution device to be temporarily increased to a value greater than the current value corresponding to the target torque distribution amount, and then returned to the current value corresponding to the target torque distribution amount, and repeating the temporary increasing of the input current at least at intervals of a predetermined time.