A compact geared reduction unit for application with transmission shaft subjected to radial loads, comprising a box-like body inside which a gear system is accommodated for the transmission of rotary motion from a driving shaft to a transmission shaft, which is provided with an output reduction stage of the epicyclic type; the output reduction stage comprises a driving sun gear which rotates about a main axis and a ring gear which is integrally associated with the box-like body, between which multiple planet gears are engaged which are supported in rotation about respective longitudinal axes which are parallel to the main axis by a transmission planet carrier, which in turn rotates about the main axis and is associated so as to be integral in rotation with the transmission shaft at a connection region. The reduction unit furthermore provides for rolling means adapted to support radial loads associated with the transmission shaft.

A mechanical gearbox for aircraft includes a sun gear with an external toothing, a ring gear with an internal toothing, and planet gears which are meshed with the sun gear and the ring gear and which each have a first toothing of average diameter D32 meshed with the toothing of the sun gear, and a second toothing of average diameter D28, different from D32, meshed with the internal toothing of the ring gear. The planet gears are guided by hydrodynamic bearings which each include a first smooth guiding surface extending at least partly under the first toothing, and a second smooth guiding surface extending at least partly under the second toothing.

A mechanical gearbox for aircraft includes a sun gear with an external toothing, a ring gear with an internal toothing, and planet gears which are meshed with the sun gear and the ring gear and which each have a first toothing of average diameter D32 meshed with the toothing of the sun gear, and a second toothing of average diameter D28, different from D32, meshed with the internal toothing of the ring gear. The planet gears are guided by hydrodynamic bearings which each include a first smooth guiding surface extending at least partly under the first toothing, and a second smooth guiding surface extending at least partly under the second toothing.

A universal driving device includes a sun gear rotatably provided, a ring gear, wherein a rotation axis of the ring gear is moved relative to a rotation axis of the sun gear in a plane of rotation parallel to a plane of rotation of the sun gear, at least one gear train configured to allow relative motion between the rotation axes of the sun gear and the ring gear and to form a continuous power transmission state between the sun gear and the ring gear, and at least one balance gear engaged with the ring gear.

An actuator is provided which includes a stationary frame; an output plate disposed within said stationary frame; a top plate; a stator disposed between said stationary frame and said top plate, said stator describing an annulus; a rotor disposed within the annulus of said stator; a principal bearing disposed between said stationary frame and said output plate; a pinion gear; and a star gear which meshes with said pinion gear.

An actuator is provided which includes a stationary frame; an output plate disposed within said stationary frame; a top plate; a stator disposed between said stationary frame and said top plate, said stator describing an annulus; a rotor disposed within the annulus of said stator; a principal bearing disposed between said stationary frame and said output plate; a pinion gear; and a star gear which meshes with said pinion gear.

Provided is an electric actuator, including: a driving motor (2); a motion conversion mechanism (6) configured to convert a rotary motion of the driving motor (2) to a linear motion; a transmission gear mechanism (5) configured to transmit a driving force from the driving motor (2) to the motion conversion mechanism (6); and a speed reduction mechanism (3) configured to reduce a speed of the rotary motion of the driving motor (2), and output the rotary motion reduced in speed to the transmission gear mechanism (5), wherein a side of one end portion of a rotation shaft (18) of a gear (16) of the transmission gear mechanism (5) is rotatably supported by a bearing (19), and a side of another end portion of the rotation shaft (18) of the gear (16) is rotatably supported by the output shaft (2a) of the driving motor (2).

A gear assembly including a first gear including a rim and a plurality of teeth. The plurality of teeth is configured to contact one or more of another plurality of teeth. A non-axisymmetric structure is defined at the rim. The non-axisymmetric structure is a non-contacting structure of the gear assembly.

A gear assembly including a first gear including a rim and a plurality of teeth. The plurality of teeth is configured to contact one or more of another plurality of teeth. A non-axisymmetric structure is defined at the rim. The non-axisymmetric structure is a non-contacting structure of the gear assembly.

A power transmission device includes a pin gear having a plurality of power transmission pins that are relatively moved corresponding to a tooth shape formed on an outer gear, a motor arranged in a direction crossing a rotation axis of the pin gear, and generating power to rotate the pin gear, and a motion transfer unit connected to the pin gear and the motor between the pin gear and the motor, and transferring a rotational motion of the motor to a rotational motion of the pin gear.