The drive unit according to the present disclosure includes two fluid motors serving as drive sources for generating rotational forces, and a channel member having a supply channel for supplying a pressure fluid to the two fluid motors. Each of the two fluid motors includes: a casing having a supply port and a discharge port for the pressure fluid; a drive shaft rotatably supported to the casing; and a motive power generating unit provided in the casing and configured to rotate the drive shaft with the pressure fluid, the pressure fluid being supplied through the supply port and discharged through the discharge port. The two fluid motors are arranged such that the respective drive shafts are disposed parallel to each other and oriented toward opposite sides along rotation axes of the drive shafts. The supply channel supplies the pressure fluid to the supply ports of the two fluid motors.

A power transmission apparatus may include a first motor-generator including a first stator fixed to a first housing, and a first rotor; a second motor-generator including a second stator fixed to a second housing and a second rotor; a first planetary gear set including first and third rotation elements connected to the first rotor and a first wheel, respectively, and a third rotation element; a second planetary gear set including fourth, fifth and sixth rotation elements connected to the second rotor, a second wheel, and the third rotation element, respectively; a first clutch selectively locking up the first planetary gear set by selectively connecting two out of the first to third rotation elements; a second clutch selectively locking up the second planetary gear set by selectively connecting two of the fourth to sixth rotation elements; and a brake selectively fixing the third and sixth rotation elements to a third housing.

A power transmission apparatus may include a first motor-generator including a first stator fixed to a first housing, and a first rotor; a second motor-generator including a second stator fixed to a second housing and a second rotor; a first planetary gear set including first and third rotation elements connected to the first rotor and a first wheel, respectively, and a third rotation element; a second planetary gear set including fourth, fifth and sixth rotation elements connected to the second rotor, a second wheel, and the third rotation element, respectively; a first clutch selectively locking up the first planetary gear set by selectively connecting two out of the first to third rotation elements; a second clutch selectively locking up the second planetary gear set by selectively connecting two of the fourth to sixth rotation elements; and a brake selectively fixing the third and sixth rotation elements to a third housing.

A gas turbine engine according to an example of the present disclosure includes, among other things, a propulsor section including a propulsor, a gear reduction, a first spool including a first compressor, a first turbine and a first shaft, and a second spool including a second compressor, a second turbine and a second shaft. The gear reduction includes a carrier and a plurality of gears. The plurality of gears include a sun gear, a ring gear, and a plurality of intermediate gears that engage the sun gear and the ring gear. At least two of the plurality of gears are double helical gears in meshed engagement.

A gas turbine engine according to an example of the present disclosure includes, among other things, a propulsor section including a propulsor, a gear reduction, a first spool including a first compressor, a first turbine and a first shaft, and a second spool including a second compressor, a second turbine and a second shaft. The gear reduction includes a carrier and a plurality of gears. The plurality of gears include a sun gear, a ring gear, and a plurality of intermediate gears that engage the sun gear and the ring gear. At least two of the plurality of gears are double helical gears in meshed engagement.

Provided is a speed reducer including: a first reduction unit disposed at an input stage of a multi-stage reduction unit that decelerates a rotational driving force of an electric motor from an input stage side toward an output stage side and transmits the decelerated rotational driving force to a rotational drive unit; a first ring gear meshed with first planetary gears provided in the first reduction unit; and a third reduction unit disposed at an output stage of the multi-stage reduction unit and having a first case. The first ring gear is provided in the first case of the third reduction unit.

Provided is a speed reducer including: a first reduction unit disposed at an input stage of a multi-stage reduction unit that decelerates a rotational driving force of an electric motor from an input stage side toward an output stage side and transmits the decelerated rotational driving force to a rotational drive unit; a first ring gear meshed with first planetary gears provided in the first reduction unit; and a third reduction unit disposed at an output stage of the multi-stage reduction unit and having a first case. The first ring gear is provided in the first case of the third reduction unit.

A gearbox includes a sun gear, a plurality of planetary gears meshed with the sun gear, a rotating frame supporting the planetary gears, and a housing with an internal ring gear meshed with the planetary gears. The planetary gears include a first gear and a second gear coaxially connected to each other along an axial direction and rotating synchronously, the first gear meshed with the sun gear, and the second gear meshed with the internal ring gear of the housing. The rotating frame received in the housing has an upper frame and a lower frame with a central hole, each of the plurality of planetary gears is arranged between the upper frame and the lower frame by a mounting pin, the lower frame is supported by a flange connected to the housing, the sun gear is driven to rotate so as to operate the rotating frame. The gearbox of the present disclosure has low vibration and low noise.

A turbomachine engine includes a fan assembly and a core engine comprising a turbine and an input shaft rotatable with the turbine is provided. A single-stage epicyclic gear assembly receives the input shaft at a first speed and drives an output shaft coupled to the fan assembly at a second speed. A sun gear rotates about a longitudinal centerline of the gear assembly and has a sun gear-mesh region along the longitudinal centerline of the gear assembly where the sun gear is configured to contact a plurality of planet gears. A ring gear-mesh region is provided along the longitudinal centerline of the gear assembly where a ring gear is configured to contact the plurality of planet gears. The sun gear-mesh region is axially offset from the ring gear-mesh region along the longitudinal centerline.

A turbomachine engine includes a fan assembly and a core engine comprising a turbine and an input shaft rotatable with the turbine is provided. A single-stage epicyclic gear assembly receives the input shaft at a first speed and drives an output shaft coupled to the fan assembly at a second speed. A sun gear rotates about a longitudinal centerline of the gear assembly and has a sun gear-mesh region along the longitudinal centerline of the gear assembly where the sun gear is configured to contact a plurality of planet gears. A ring gear-mesh region is provided along the longitudinal centerline of the gear assembly where a ring gear is configured to contact the plurality of planet gears. The sun gear-mesh region is axially offset from the ring gear-mesh region along the longitudinal centerline.