Abstract: A four-wheel-drive vehicle includes: an engine as a driving source; a right front wheel and a left front wheel as main driving wheels and a right rear wheel and a left rear wheel as sub-driving wheels that are driven by a driving force of the engine; a driving force transmission device that transmits part of the driving force of the engine to the right rear wheel and the left rear wheel; and a control device that controls the driving force transmission device. The control device is configured to, when the four-wheel-drive vehicle moves straight forward, adjust the driving force transmitted to the right rear wheel and the left rear wheel by the driving force transmission device so as to maintain a state where the magnitude of a front-rear force generated in the right front wheel and the left front wheel is greater than zero.

Abstract: Systems, apparatus, and methods to control fluid associated with vehicle clutches are disclosed. A disclosed apparatus includes a drive unit assembly for a vehicle. The drive unit assembly includes a housing and a clutch in a cavity of the housing. Rotation of a drum of the clutch expels a fluid from the cavity. The apparatus also includes a vehicle controller configured to disengage the clutch via an actuator. Actuation of the actuator reduces a flow of the fluid into the cavity. The vehicle controller is also configured to maintain engagement of a vehicle transfer device operatively coupled between a vehicle transmission and the drum such that the drum continues to rotate for a time interval during which the clutch is disengaged.

Abstract: Systems, apparatus, and methods to control fluid associated with vehicle clutches are disclosed. A disclosed apparatus includes a drive unit assembly for a vehicle. The drive unit assembly includes a housing and a clutch in a cavity of the housing. Rotation of a drum of the clutch expels a fluid from the cavity. The apparatus also includes a vehicle controller configured to disengage the clutch via an actuator. Actuation of the actuator reduces a flow of the fluid into the cavity.

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 four-wheel drive vehicle includes front wheels, rear wheels to which a driving force of an engine is transmitted via a propeller shaft, a dog clutch that enables blocking of transmission of the driving force from the engine to the propeller shaft, and a multi-disc clutch that enables blocking of transmission of the driving force from the propeller shaft to the rear wheels. During two-wheel driving in which the transmission of the driving force through the dog clutch and the multi-disc clutch is blocked, an ECU in the four-wheel drive vehicle calculates an estimated driving force estimated to be transmitted to the front wheels based on a vehicle speed and an amount of acceleration operation. The ECU allows the multi-disc clutch to transmit the driving force when the estimated driving force is larger than a driving force threshold defined according to a slip limit torque for the front wheels.

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 four-wheel-drive vehicle includes a first driving force transmission system and a second driving force transmission system. A control device controls the second driving force transmission system. The control device includes a road surface state determination section that determines whether a coefficient of friction of a road surface is equal to or higher than a predetermined value based on an index value regarding the coefficient of friction of the road surface, controls a dog clutch such that the dog clutch is engaged irrespective of the index value regarding the coefficient of friction of the road surface when an ignition switch is brought into the on-state, and controls the dog clutch such that the dog clutch is brought into the disengaged state when it is determined that the coefficient of friction of the road surface is equal to or higher than the predetermined value.

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: A seal member is attached to a cover which occludes a gear case as a housing unit. The seal member is formed of elastomer and integrally formed with: a plate-shaped portion formed into a disc shape which covers the inner surface of the cover; an inner seal portion which is positioned on the inner peripheral edge of a through-hole, and comes into sliding contact with the outer peripheral surface of an output member; an outer seal portion which is positioned on the periphery of the cover, and comes into contact with the opening end of the housing unit; and anchor portions which latch onto the front surface of the cover via mounting holes provided to the cover. The boundary between the seal member and the cover extends only to the outside of the gear case, and does not extend to the inside of the gear case.

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 four-wheel drive vehicle includes front wheels, rear wheels to which a driving force of an engine is transmitted via a propeller shaft, a dog clutch that enables blocking of transmission of the driving force from the engine to the propeller shaft, and a multi-disc clutch that enables blocking of transmission of the driving force from the propeller shaft to the rear wheels. During two-wheel driving in which the transmission of the driving force through the dog clutch and the multi-disc clutch is blocked, an ECU in the four-wheel drive vehicle calculates an estimated driving force estimated to be transmitted to the front wheels based on a vehicle speed and an amount of acceleration operation. The ECU allows the multi-disc clutch to transmit the driving force when the estimated driving force is larger than a driving force threshold defined according to a slip limit torque for the front wheels.

Abstract: A seal member is attached to a cover which occludes a gear case as a housing unit. The seal member is formed of elastomer and integrally formed with: a plate-shaped portion formed into a disc shape which covers the inner surface of the cover; an inner seal portion which is positioned on the inner peripheral edge of a through-hole, and comes into sliding contact with the outer peripheral surface of an output member; an outer seal portion which is positioned on the periphery of the cover, and comes into contact with the opening end of the housing unit; and anchor portions which latch onto the front surface of the cover via mounting holes provided to the cover. The boundary between the seal member and the cover extends only to the outside of the gear case, and does not extend to the inside of the gear case.

Abstract: A seal member is attached to a cover which occludes a gear case as a housing unit. The seal member is formed of elastomer and integrally formed with: a plate-shaped portion formed into a disc shape which covers the inner surface of the cover; an inner seal portion which is positioned on the inner peripheral edge of a through-hole, and comes into sliding contact with the outer peripheral surface of an output member; an outer seal portion which is positioned on the periphery of the cover, and comes into contact with the opening end of the housing unit; and anchor portions which latch onto the front surface of the cover via mounting holes provided to the cover. The boundary between the seal member and the cover extends only to the outside of the gear case, and does not extend to the inside of the gear case.

Abstract: An ECU of a four wheel drive vehicle controls a transmission torque of a driving force transmission apparatus provided between a rear differential and a left rear wheel. The ECU includes a first computation unit that computes a command torque to be transmitted to the left rear wheel by the driving force transmission apparatus, based on a traveling state of the four wheel drive vehicle; and a second computation unit that corrects the command torque computed by the first computation unit, if a difference between rotation speeds of a pair of side gears of the rear differential is larger than or equal to a predetermined value.

Abstract: A four-wheel-drive vehicle includes a dog clutch provided between a propeller shaft and an engine, a torque coupling provided between a rear differential and rear wheels, and an ECU that controls the dog clutch and the torque coupling. When a drive mode is switched from a two-wheel-drive mode where the transmissions of torque by the dog clutch and the torque coupling are both interrupted, to a four-wheel-drive mode, the ECU sets the amount of torque that is transmitted by the torque coupling to a first torque value (T1) to increase the speed of rotation of the propeller shaft, and then sets the amount of torque that is transmitted by the torque coupling to a second torque value (T2) that is lower than the first torque value (T1), and engages the dog clutch when the rotations of first and second rotary members of the dog clutch are synchronized with each other.

Abstract: A driving force distribution controller comprises: a control device determining the value of torque which must be transmitted to a rear wheel; and a driving force transmission device transmitting torque corresponding to the torque value determined by the control device to the rear wheel. The control device reduces a torque value calculated based on an opening degree of an accelerator and a rotational speed difference when the rotational speed of an engine is lower than a first threshold value but higher than a second threshold value.

Abstract: A four-wheel-drive vehicle includes a clutch that is able to allow and interrupt transmission of driving force to a propeller shaft, and a traction control unit that controls at least one of the driving force generated by an engine and braking force applied to right and left front wheels to suppress a slip of the right and left front wheels. When the drive mode is switched from a two-wheel-drive mode to a four-wheel-drive mode, if the relative rotational speed between a first rotary member and a second rotary member constituting a clutch is equal to or higher than a predetermined value, an ECU outputs a control command signal for suppressing the slip of the right and left front wheels to the traction control unit.

Abstract: A four-wheel-drive vehicle includes: a drive source which generates torque forming a driving force of the vehicle; a driving force transmission system which transmits the torque of the drive source to main driven wheels and auxiliary driven wheels; and a dog clutch provided in the driving force transmission system and capable of transmitting the torque to an auxiliary driven wheel side by engagement of a recess portion and a protruding portion. The vehicle further includes: a determination unit which determines whether a friction coefficient of a road surface is lower than a predetermined value based on an index value relating to the friction coefficient of the road surface; and a control unit which generates a control signal which causes engagement of the dog clutch before the vehicle starts when the determination unit determines that the friction coefficient of the road surface is lower than the predetermined value.

Abstract: An ECU of a four wheel drive vehicle controls a transmission torque of a driving force transmission apparatus provided between a rear differential and a left rear wheel. The ECU includes a first computation unit that computes a command torque to be transmitted to the left rear wheel by the driving force transmission apparatus, based on a traveling state of the four wheel drive vehicle; and a second computation unit that corrects the command torque computed by the first computation unit, if a difference between rotation speeds of a pair of side gears of the rear differential is larger than or equal to a predetermined value.

Abstract: A four-wheel-drive vehicle includes a first driving force transmission system and a second driving force transmission system. A control device controls the second driving force transmission system. The control device includes a road surface state determination section that determines whether a coefficient of friction of a road surface is equal to or higher than a predetermined value based on an index value regarding the coefficient of friction of the road surface, controls a dog clutch such that the dog clutch is engaged irrespective of the index value regarding the coefficient of friction of the road surface when an ignition switch is brought into the on-state, and controls the dog clutch such that the dog clutch is brought into the disengaged state when it is determined that the coefficient of friction of the road surface is equal to or higher than the predetermined value.