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 four-wheel drive force distribution apparatus for distributing drive forces to the wheels of a four-wheel drive vehicle, in which the distribution of drive force to the front inside wheel (2a) and the distribution of drive force to the rear inside wheel (3a) are adjusted based on a ground load of the front inside wheel (2a) and a ground load of the rear inside wheel (3a) when the vehicle is turning, and the distribution of drive force to the front inside wheel (2a) compared with distribution of drive force to the rear inside wheel (3a) is reduced the smaller the ratio of the ground load of the front inside wheel (2a) to the ground load of the rear inside wheel (3a) during turning.

A four-wheel drive force distribution apparatus for distributing drive forces to the wheels of a four-wheel drive vehicle, in which the distribution of drive force to the front inside wheel (2a) and the distribution of drive force to the rear inside wheel (3a) are adjusted based on a ground load of the front inside wheel (2a) and a ground load of the rear inside wheel (3a) when the vehicle is turning, and the distribution of drive force to the front inside wheel (2a) compared with distribution of drive force to the rear inside wheel (3a) is reduced the smaller the ratio of the ground load of the front inside wheel (2a) to the ground load of the rear inside wheel (3a) during turning.

An improved twin clutch, two-speed disconnect secondary drive unit, which may be configured as a rear drive unit (RDU) for an all wheel drive vehicle is provided. The RDU is driven through an input shaft, which is connected to a vehicle drive source such as a motor, and includes a twin clutch assembly, which is connected to the drive shaft and is selectively actuated to drive left and right main shafts, which drive respective wheels of the vehicle. The RDU further includes a modular a shift assembly mountable to one or both of said main shafts to drive output shafts, wherein each shift assembly is selectively operable between the hi-range and lo-range modes to shift driving operation of the output shafts between hi-speed and lo-speed operation. The shift assembly may be controlled by improved mono-stable or bi-stable actuators.

A through the road (TTR) hybridization strategy is proposed to facilitate introduction of hybrid electric vehicle technology in a significant portion of current and expected trucking fleets. In some cases, the technologies can be retrofitted onto an existing vehicle (e.g., a truck, a tractor unit, a trailer, a tractor-trailer configuration, at a tandem, etc.). In some cases, the technologies can be built into new vehicles. In some cases, one vehicle may be built or retrofitted to operate in tandem with another and provide the hybridization benefits contemplated herein. By supplementing motive forces delivered through a primary drivetrain and fuel-fed engine with supplemental torque delivered at one or more electrically-powered drive axles, improvements in overall fuel efficiency and performance may be delivered, typically without significant redesign of existing components and systems that have been proven in the trucking industry.

A rotary power transmission device includes a housing, a clutch, an actuator and a retaining body. The housing has an annular surface and an interior in which multiple components are received for rotation. The clutch is received within the housing and has a clutch ring selectively engageable with one of said multiple components. The actuator has a limit surface, a coil and a plunger driven for movement along an axis and relative to the clutch, and the plunger is received over and movable along the annular surface. The retaining body has a blocking surface radially overlapped with the limit surface and arranged to be contacted by the limit surface to prevent removal of the plunger from the annular surface.

A secondary drive unit (SDU) for the secondary axis of an all wheel drive vehicle consists of an SDU housing defining a first section for receiving a main shaft which is connected to a drive source and a second section for enclosing a twin clutch assembly. The twin clutch assembly has a common clutch housing connected to the main shaft, a left clutch for selectively connecting a left output shaft and the clutch housing, a right clutch for selectively connecting a right output shaft and the clutch housing, and a rigid center plate separating the left and right clutches. The twin clutch assembly may be activated by a dual action piston assembly to decrease all wheel drive synchronization and connection response times.

A secondary drive unit (SDU) for the secondary axis of an all wheel drive vehicle consists of an SDU housing defining a first section for receiving a main shaft which is connected to a drive source and a second section for enclosing a twin clutch assembly. The twin clutch assembly has a common clutch housing connected to the main shaft, a left clutch for selectively connecting a left output shaft and the clutch housing, a right clutch for selectively connecting a right output shaft and the clutch housing, and a rigid center plate separating the left and right clutches. The twin clutch assembly may be activated by a dual action piston assembly to decrease all wheel drive synchronization and connection response times.

A transfer includes: an input shaft; a motor; first and second output shafts; first and second planetary gear devices; an input switching unit; a transmission switching unit; and a distribution switching unit. Further, connection states of the input shaft, the first and the second planetary gear devices, the first and the second output shafts can be switched to a plurality of modes including first, second, and third modes by the input switching unit, the transmission switching unit, and the distribution switching unit.

A motor vehicle, including a drivable front axle, a drivable rear axle, an internal combustion engine, an automatic transmission coupled thereto, and a switchable torque distribution unit which is coupled to the automatic transmission and enables all-wheel drive, which torque distribution unit is coupled to the front axle and the rear axle. A torque generated by the internal combustion engine can be directed from the torque distribution unit either to the front or rear axle or distributed to both axles. An electric machine is provided which is coupled to the rear axle. A torque generated by the electric machine which is provided to the rear axle is provided to the torque distribution unit via the coupling and can also be provided from this torque distribution unit to the front axle.