A control system of a four-wheel drive vehicle and a gradient value setting device of the vehicle is provided so as to reliably control a wheel skid despite the vehicle facing an intersecting direction intersecting a maximum tilt line direction. The vehicle includes an engine, front and rear wheels, an electronic control 4WD coupling, and a control unit. The distribution amount of the driving force to the rear wheels is set by the electronic control 4WD coupling. The control unit determines whether or not the vehicle faces the intersecting direction on the inclined road, and if so, sets the driving force distribution amount so that the difference between the driving force distribution amount to the front wheels and to the rear wheels is smaller as compared with on a flat road, and commands the electronic control 4WD coupling to distribute the driving force by the distribution amount.

An electronic self-locking connect and disconnect system for vehicles. The system includes a motor which turns a gear that meshes with a ring gear contained within a housing. The ring gear meshes with a lead screw thread on an outer surface of a lead screw. When the motor is activated the ring gear rotates the lead screw thread which selectively engages or disengages the clutch. A groove extends on the outer surface of and transverse to the lead screw thread. A pin extends radially inward from an inner surface of the housing till part of the pin is located within the groove. When the pin contacts a radial wall of the groove it prevents further rotation of the lead screw which prevents the stub shaft from axially moving beyond predetermined points. A spring and a sliding collar may be utilized to accommodate full motor travel regardless of the clutch state.

The power transmission device includes an internal-combustion engine 25, a drive-source-side shaft, a flywheel 30 provided on the drive-source-side shaft 2, a speed changer 10, which has an input shaft and an output, and clutches C1 and C2 capable of releasably transmitting the power between the drive-source-side shaft 2 and the input shaft, wherein the internal-combustion engine 25 and the speed changer 10 are disposed in the traveling direction of the vehicle. A differential gear mechanism 101 and a drive shaft 201, which are positioned between the flywheel 30 and the clutches C1 and C2 so as to be orthogonal to the drive-source-side shaft 2 and which transmit the power output from the speed changer 10 to left and right drive wheels RW, are provided. The drive shaft 201 is disposed above the central axis of rotation of the drive-source-side shaft 2.

The power transmission device includes an internal-combustion engine 25, a drive-source-side shaft, a flywheel 30 provided on the drive-source-side shaft 2, a speed changer 10, which has an input shaft and an output, and clutches C1 and C2 capable of releasably transmitting the power between the drive-source-side shaft 2 and the input shaft, wherein the internal-combustion engine 25 and the speed changer 10 are disposed in the traveling direction of the vehicle. A differential gear mechanism 101 and a drive shaft 201, which are positioned between the flywheel 30 and the clutches C1 and C2 so as to be orthogonal to the drive-source-side shaft 2 and which transmit the power output from the speed changer 10 to left and right drive wheels RW, are provided. The drive shaft 201 is disposed above the central axis of rotation of the drive-source-side shaft 2.

An off-road vehicle has two front wheels and two rear wheels, the rear wheels being connected to a spool gear driven by a motor. The vehicle also has a left front brake, a right front brake and a single rear brake. Speeds of left and right front wheels are respectively monitored by left and right front speed sensors. A single sensor monitors a common speed of left and right rear wheels. Two user actuated braking input devices, for example a hand lever and a foot lever, may be used independently or concurrently to provide a braking command. An anti-lock braking system may use speed measurements from the various speed sensors to control selective application of pressure on the left front brake, the right front brake and the rear brake.

An off-road vehicle has two front wheels and two rear wheels, the rear wheels being connected to a spool gear driven by a motor. The vehicle also has a left front brake, a right front brake and a single rear brake. Speeds of left and right front wheels are respectively monitored by left and right front speed sensors. A single sensor monitors a common speed of left and right rear wheels. Two user actuated braking input devices, for example a hand lever and a foot lever, may be used independently or concurrently to provide a braking command. An anti-lock braking system may use speed measurements from the various speed sensors to control selective application of pressure on the left front brake, the right front brake and the rear brake.

A hydrostatic traction drive includes a first hydraulic machine that is coupled to a drive unit. The first hydraulic machine is hydraulically arranged in a hydraulic circuit with a second hydraulic machine. The second hydraulic machine has a drive shaft that is connected in a rotationally fixed fashion to a lockable differential. The traction drive has a control unit that is configured so as to control at least one measure for traction control as a function of a rotational speed of the second hydraulic machine. The at least one measure includes one or more of a measure for detecting a loss of traction and a measure for overcoming the loss of traction. A method for controlling the traction drive includes eliminating a loss of traction of the traction drive with use of the control unit as a function of the rotational speed of the second hydraulic machine.

A powertrain for a motor vehicle, with a differential planetary gear system, which has at least one ring gear with ring gear toothing, at least one sun gear with sun gear toothing, planetary gears which engage with the ring gear toothing on one side and with the sun gear toothing on the other side, and a planetary gear carrier, on which the planetary gears are rotatably mounted. The ring gear toothing and the sun gear toothing have the same number of respective gear wheel teeth.

A vehicle drive system includes a slip acquisition unit that acquires occurrence of excessive slip, an addition slip point calculating unit that calculates addition slip points in a time-discrete manner, based on having acquired that the excessive slip has occurred, a cumulative slip point calculating unit that accumulates the addition slip points and calculates a cumulative slip point over time, a drive state switching unit that switches between 2WD and AWD based on cumulative slip points and a drive state switching threshold value, and a cumulative slip point resetting unit triggered by a lateral acceleration correlation value of the vehicle reaching a lateral acceleration threshold value or higher, or a drive force correlation value of the drive wheels reaching a drive force correlation threshold value or higher, to reset the cumulative slip point to a value smaller than the drive state switching threshold value.

A vehicle drive system includes a slip acquisition unit that acquires occurrence of excessive slip, an addition slip point calculating unit that calculates addition slip points in a time-discrete manner, based on having acquired that the excessive slip has occurred, a cumulative slip point calculating unit that accumulates the addition slip points and calculates a cumulative slip point over time, a drive state switching unit that switches between 2WD and AWD based on cumulative slip points and a drive state switching threshold value, and a cumulative slip point resetting unit triggered by a lateral acceleration correlation value of the vehicle reaching a lateral acceleration threshold value or higher, or a drive force correlation value of the drive wheels reaching a drive force correlation threshold value or higher, to reset the cumulative slip point to a value smaller than the drive state switching threshold value.