An axle disconnect device including a shift collar slidable in an axial direction of the axle disconnect device, the shift collar switchable between a connect mode and a disconnect mode; a first solenoid including a threaded end; a second solenoid including locker arm; a return spring configured to bias a movement of the shift collar towards the connect mode; a groove on the shift collar configured to receive the locker arm when the shift collar is in the connect mode; and a lead screw on the shift collar configured to mesh with the threaded end to move the shift collar toward the disconnect mode against the bias force of the return spring.

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 thus—in a drive-dependent and switchable manner—determines 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.

An all-wheel-drive vehicle includes a primary axle operably coupled to an engine and a secondary axle having an input operably coupled to the engine a first halfshaft, a second halfshaft, a first clutch selectively connecting the first halfshaft to the input, and a second clutch selectively connecting the second halfshaft to the input. A transmission has an input coupled to the engine and output coupled to the primary drive axle. A driveshaft couples a power-transfer unit and the input, and a third clutch selectively couples the output to the driveshaft. A controller is programmed to, during a power-limiting routine, command a torque to the engine based on closed-loop feedback control such that the torque decreases when a calculated slip of a selected one of the first and second clutches is greater than a target slip of the selected clutch and increases when the calculated slip is less than the target slip.

A drive switching mechanism of a utility vehicle includes: a two-wheel drive and four-wheel drive switching device that switches between two-wheel drive and four-wheel drive of the utility vehicle; and a control unit that controls the drive switching mechanism. The two-wheel drive and four-wheel drive switching device switches between two-wheel drive and four-wheel drive by using a first clutch. The control unit permits the two-wheel drive and four-wheel drive switching device to switch from two-wheel drive to four-wheel drive when a rotation difference of the first clutch becomes equal to or smaller than a predetermined value.

A method for operating a clutch of a drive train of a vehicle wherein the clutch, a drive motor primary axis having first wheels that can be driven by the drive motor as first axis and a second axis having second wheels are driven by the drive motor via the clutch as second axis, with the clutch being adjusted between a closed position, wherein a first coupling torque of the clutch is set, and at least one second position differing from the closed position, wherein a second coupling torque of the clutch that is lower than the first coupling torque is set: determining at least one coefficient of friction of a roadway the vehicle is located on; and as a factor of the determined coefficient of friction: adjusting a basic torque of the clutch, with the clutch being prestressed in the second position by the basic torque.

A method for controlling a clutch unit for a drive train of a motor vehicle, wherein the clutch unit comprises a wet-running friction clutch for controllably transmitting torque from an input element to an output element of the clutch unit, wherein the clutch unit comprises oil for cooling the friction clutch, wherein heat inputs which contribute to heating the oil of the clutch unit are calculated, heat outflows which contribute to cooling the oil of the clutch unit are calculated and, as a function of the heat inputs and heat outflows, a maximum admissible clutch torque is calculated, and wherein the current clutch torque of the friction clutch is limited to the maximum admissible clutch torque.

Controlling a clutch by means of an actuator, wherein at least one first shaft can be torque-transmittingly connected to a second shaft by means of the clutch, the clutch in one of at least three states, where in an disengaged first state, a torque cannot be transmitted, in a second state, a torque can be transmitted such that the speeds of the first shaft and the second shaft are synchronized in the second state, and in an engaged third state, a required torque can be transmitted; wherein, in various states and in an operating mode associated with the particular state, the actuator is adjusted at a different speed in order to adjust the clutch.

A utility vehicle includes: a pair of front wheels; a pair of rear wheels; at least one front wheel power source configured to drive the front wheels and not to drive the rear wheels; at least one rear wheel power source configured to drive the rear wheels and not to drive the front wheels; and a controller that controls the front wheel power source and the rear wheel power source. Upon receiving a predetermined two-wheel drive command, the controller brings the front wheel power source into a non-operative state while allowing the rear wheel power source to drive the rear wheels. Upon receiving a predetermined four-wheel drive command, the controller brings the front wheel power source into operation while allowing the rear wheel power source to drive the rear wheels.

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 method for operating a clutch of a drive train of a vehicle wherein the clutch, a drive motor primary axis having first wheels that can be driven by the drive motor as first axis and a second axis having second wheels are driven by the drive motor via the clutch as second axis, with the clutch being adjusted between a closed position, wherein a first coupling torque of the clutch is set, and at least one second position differing from the closed position, wherein a second coupling torque of the clutch that is lower than the first coupling torque is set: determining at least one coefficient of friction of a roadway the vehicle is located on; and as a factor of the determined coefficient of friction: adjusting a basic torque of the clutch, with the clutch being prestressed in the second position by the basic torque.