A power transmission system includes: a power source; a speed change unit, where the speed change unit is selectively power-coupled to the power source; a first motor generator unit; a system power output portion; and a mode conversion device, where the mode conversion device includes: a conversion device input portion and a conversion device output portion, the conversion device input portion outputs power from at least one of the power source and the first motor generator unit, the conversion device output portion is connected to an input end of the system power output portion, and the conversion device input portion is selectively power-coupled to the conversion device output portion; and when the conversion device input portion is power-coupled to the conversion device output portion, the rotational speed of the conversion device input portion is greater than or equal to the rotational speed of the conversion device output portion.

A drive-train for a vehicle having at least one electric drive unit (EM) which is, or can be, coupled by way of a driveshaft (AW) to at least a first transmission stage (i1), a second transmission stage (i2) and a third transmission stage (i3). At least one shifting device having at least two interlocking shifting elements (S1, S2) is provided for engaging the first and second transmission stages (i1, i2), and a frictional shifting element (S3) is provided for traction a force support of the first and the second transmission stages. The frictional shifting element (S3) is also provided for engaging the third transmission stage (i3).

A manufacturing method for a power transmission mechanism including: first and second shafts having first and second double helical gears; first and second rolling bearings rotatably supporting the shafts with respect to a case and restrict movement of the shafts in an axial direction thereof, includes an assembling step of assembling an outer ring of the first rolling bearing and an outer ring of the second rolling bearing to the case in a state where the outer rings are movable in the respective axial directions; and a positioning step of determining axial positions of the first rolling bearing and the second rolling bearing while rotating the first shaft and the second shaft in a state where the first double helical gear and the second double helical gear are meshed with each other, after the assembling step.

A manufacturing method for a power transmission mechanism including: first and second shafts having first and second double helical gears; first and second rolling bearings rotatably supporting the shafts with respect to a case and restrict movement of the shafts in an axial direction thereof, includes an assembling step of assembling an outer ring of the first rolling bearing and an outer ring of the second rolling bearing to the case in a state where the outer rings are movable in the respective axial directions; and a positioning step of determining axial positions of the first rolling bearing and the second rolling bearing while rotating the first shaft and the second shaft in a state where the first double helical gear and the second double helical gear are meshed with each other, after the assembling step.

An axle assembly having an electric motor module, a drive pinion, and at least one rotor bearing assembly. The electric motor module may have a rotor. The rotor and the drive pinion may be rotatable about a first axis. The first rotor bearing assembly may extend between the drive pinion and the rotor.

An axle assembly having an electric motor module, a drive pinion, and at least one rotor bearing assembly. The electric motor module may have a rotor. The rotor and the drive pinion may be rotatable about a first axis. The first rotor bearing assembly may extend between the drive pinion and the rotor.

A high-ratio differential reducer is provided. A carrier is connected to an input shaft. At least one planetary gear is supported to be rotatably supported by the carrier in an eccentric state from the carrier. A fixed annular gear meshes with the planetary gear in a state of being coaxially arranged with the carrier. A rotating annular gear meshes with the planetary gear in a state of being coaxially arranged with the fixed annular gear and has the number of teeth set by Equation below:
Z.sub.o=Z.sub.f±N.sub.p  (1),
where Z.sub.o is the number of teeth of the rotating annular gear, Z.sub.f is the number of teeth of the fixed annular gear, and N.sub.p is the number of planetary gears.

Piston apparatus for use with vehicle clutches are disclosed. A disclosed drive unit assembly for a vehicle includes a housing defining a first cavity and a second cavity fluidly coupled together. The drive unit assembly also includes a clutch positioned in the first cavity. Rotation of the clutch conveys a fluid from the first cavity to the second cavity. The drive unit assembly also includes a port extending from the second cavity to the first cavity to receive the fluid. The drive unit assembly also includes a piston positioned in the first cavity proximate to the port and configured to operate the clutch. Movement of the piston relative to the port controls a flow of the fluid through the port from the second cavity to the first cavity.

An axle assembly for frame rail vehicles is described herein. The axle assembly also includes a drive unit housing that includes an interior cavity enclosing first and second electric machines, a common gear reduction, a differential gear set, and a speed change mechanism with the first and second axle shafts partially disposed within the interior cavity and extending out of the drive unit housing. The drive unit housing includes a central cavity, a lower cavity, a first machine cavity, and a second machine cavity. The central cavity includes the common gear reduction and the axis of rotation of the first and second axle shafts. The lower cavity accumulates a volume of gearbox fluid with the speed change mechanism at least partially immersed in the lower cavity. The first machine cavity includes the first electric machine and the second machine cavity includes the second electric machine.

A differential includes a housing, an internal gear pair having an oscillating gear A and an output gear A, an internal gear pair consisting of an oscillating gear B and an output gear B, at least two A-type intermediate gears, and at least two B-type intermediate gears. Each A-type intermediate gear is radially fixed to the housing, and an axis of rotation of each A-type intermediate gear is parallel to an axis of rotation of the housing. Each A-type intermediate gear is meshed with at least one B-type intermediate gear, and the gear ratio of each gear pair consisting of an A-type intermediate gear and a B-type intermediate gear is the same. Each A-type intermediate gear includes an eccentric shaft having an axis parallel to its axis of rotation, and the eccentric shaft on each A-type intermediate gear has the same distance from the axis of rotation of the gear.