An axle assembly having a gear reduction unit that is configured to operatively connect an electric motor to a drive pinion. The gear reduction unit includes at least two gear sets. A shift collar is rotatable with the drive pinion and moveable along the drive pinion to couple a gear set to the drive pinion.

An automatic transmission includes a second planetary gear mechanism having a sun gear, a carrier, and a ring gear being defined as first, second and third elements, respectively, when a single pinion type planetary gear mechanism is applied; the carrier, the ring gear, and the sun gear being defined as the first, second, and third elements, respectively, when a double pinion type is applied; a first brake, a switching clutch being switchable to a first position where the third element is selectively fixed to a housing; a first clutch, a second clutch, a third clutch, and a fourth clutch. The first brake fixes a sun gear of a first planetary gear mechanism to the housing, the switching clutch fixes the third element to the housing, and the fourth clutch connects the second element to a carrier of the third planetary gear mechanism when establishing a reverse speed stage.

An automatic transmission includes a second planetary gear mechanism having a sun gear, a carrier, and a ring gear being defined as first, second and third elements, respectively, when a single pinion type planetary gear mechanism is applied; the carrier, the ring gear, and the sun gear being defined as the first, second, and third elements, respectively, when a double pinion type is applied; a first brake, a switching clutch being switchable to a first position where the third element is selectively fixed to a housing; a first clutch, a second clutch, a third clutch, and a fourth clutch. The first brake fixes a sun gear of a first planetary gear mechanism to the housing, the switching clutch fixes the third element to the housing, and the fourth clutch connects the second element to a carrier of the third planetary gear mechanism when establishing a reverse speed stage.

A multi-stage transmission for a vehicle may include an input shaft, an output shaft, first, second, third, and fourth planetary gear devices disposed between the input shaft and the output shaft to transmit rotary force, each of the first, second, third, and fourth planetary gear devices having three rotary elements, and at least six shifting elements connected to the rotary elements of the planetary gear devices.

A multi-stage transmission for a vehicle may include an input shaft, an output shaft, first, second, third, and fourth planetary gear devices disposed between the input shaft and the output shaft to transmit rotary force, each of the first, second, third, and fourth planetary gear devices having three rotary elements, and at least six shifting elements connected to the rotary elements of the planetary gear devices.

A door for allowing access to an interior space of a housing, one end of the housing is sealed with a cover having a plurality of cover components, the door comprising: a sun gear comprising a rotational axis, the sun gear is attached to the housing; a ring having a central axis coaxially disposed with the rotational axis of the sun gear; and a plurality of planetary gears evenly distributed about the central axis of the ring, each the planetary gear comprising a rotational axis and rotationally coupled to the ring and the sun gear, wherein the rotational axis of each the planetary gear is disposed parallel to the central axis of the ring, wherein each of the cover components is configured to be attached to one of the plurality of planetary gears and when the ring is rotated with respect to the housing, the plurality of cover components separate.

A door for allowing access to an interior space of a housing, one end of the housing is sealed with a cover having a plurality of cover components, the door comprising: a sun gear comprising a rotational axis, the sun gear is attached to the housing; a ring having a central axis coaxially disposed with the rotational axis of the sun gear; and a plurality of planetary gears evenly distributed about the central axis of the ring, each the planetary gear comprising a rotational axis and rotationally coupled to the ring and the sun gear, wherein the rotational axis of each the planetary gear is disposed parallel to the central axis of the ring, wherein each of the cover components is configured to be attached to one of the plurality of planetary gears and when the ring is rotated with respect to the housing, the plurality of cover components separate.

A drive device for a hybrid-drive motor vehicle, having an internal combustion engine as a primary drive, an electric engine as a secondary drive, and having planetary gear units that are coupled with one another that can be shifted into different gear steps through shift elements and brakes. The planetary gear units being connectable to a common output shaft by way of input elements and output elements. The reaction elements thereof can be coupled or firmly braked, wherein the drive device can be operated in an electromotor drive, a primary drive having gear steps (gears), or in a hybrid drive.

A drive device for a hybrid-drive motor vehicle, having an internal combustion engine as a primary drive, an electric engine as a secondary drive, and having planetary gear units that are coupled with one another that can be shifted into different gear steps through shift elements and brakes. The planetary gear units being connectable to a common output shaft by way of input elements and output elements. The reaction elements thereof can be coupled or firmly braked, wherein the drive device can be operated in an electromotor drive, a primary drive having gear steps (gears), or in a hybrid drive.

A transmission is provided having a control module, an input member, an output member, four planetary gear sets, a plurality of interconnecting members, and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices include clutches and brakes. The control module includes a control logic sequence for performing a coasting downshift of the transmission.