A propped cantilever carrier is described that can be used in planetary gear systems. The carrier can comprise cantilevered arms extending outward from a central hub. At the end of each cantilever a post can extend downward that is configured to receive bearings and gears. A plate can comprise a hole for each post in the carrier. When the plate is coupled to the carrier it can hold the bearings and gears in place and provide added strength to the carrier. The strength benefits are large compared to the light weight of the carrier (with plate) apparatus.

A steering reaction force apparatus for a vehicle includes: a housing that is openable and closable by a cover unit, a stator unit fixed to an inside of the housing, a rotor unit disposed to face the stator unit and to be rotated by electromagnetic interaction with the stator unit, a transmission shaft unit connected to the rotor unit to rotate in conjunction with the rotor unit, a power transmission unit disposed inside the rotor unit to transmit a rotational force of the transmission shaft unit to a steering shaft, and a retainer unit to support the power transmission unit with respect to the cover unit.

Methods and systems for an electric axle assembly are provided herein. The electric axle assembly includes, in one example, an electric machine with a rotor shaft having an output gear thereon. The electric axle assembly further includes a planetary gearset with a carrier coupled to a pair of axle shafts, a first ring gear with external teeth that are rotationally coupled to the output gear; and a sun gear meshing with a plurality of planet gears that rotate on the carrier, where, in the axle assembly, internal teeth of the ring gear are rotationally coupled to the plurality of planet gears, and where, in the axle assembly, the sun gear or the carrier are grounded by a housing of the electric axle assembly.

A power tool includes a motor, a speed reducer and a speed-reducing-ratio change mechanism. The speed reducer includes planetary gear mechanisms arranged in multiple stages. The speed-reducing-ratio change mechanism is configured to change a speed reducing ratio of the speed reducer in response to a change of a rotating direction of a motor shaft. At least two stages of the planetary gear mechanisms are configured such that an internal gear in each stage selectively functions as a fixed element. The speed-reducing-ratio change mechanism includes a one-way clutch and a lock mechanism configured to non-rotatably lock the internal gears of the at least two stages when the one-way clutch does not transmit rotation, and to rotate the internal gears of the at least two stages when the one-way clutch transmits rotation. The at least two stages include a speed-increasing planetary gear mechanism and a speed-reducing planetary gear mechanism.

A power tool includes a motor, a speed reducer and a speed-reducing-ratio change mechanism. The speed reducer includes planetary gear mechanisms arranged in multiple stages. The speed-reducing-ratio change mechanism is configured to change a speed reducing ratio of the speed reducer in response to a change of a rotating direction of a motor shaft. At least two stages of the planetary gear mechanisms are configured such that an internal gear in each stage selectively functions as a fixed element. The speed-reducing-ratio change mechanism includes a one-way clutch and a lock mechanism configured to non-rotatably lock the internal gears of the at least two stages when the one-way clutch does not transmit rotation, and to rotate the internal gears of the at least two stages when the one-way clutch transmits rotation. The at least two stages include a speed-increasing planetary gear mechanism and a speed-reducing planetary gear mechanism.

A gas turbine engine configured with an engine core. A fan located upstream of the engine core, the fan comprising a plurality of fan blades; and a gearbox arranged to receive an input from the core shaft and to output drive to the fan so as to drive the fan at a lower rotational speed than the core shaft. The gearbox being an epicyclic gearbox comprising a sun gear, a plurality of planet gears, a ring gear, and a planet carrier on which the planet gears are mounted, the planet carrier having an effective linear torsional stiffness and the gearbox having a gear mesh stiffness between the planet gears and the ring gear. Additionally, the product of the effective linear torsional stiffness of the planet carrier and the gear mesh stiffness between the planet gears and the ring gear is greater than or equal to 5.0×10.sup.18 N.sup.2m.sup.−2.

A hover-capable aircraft is described that comprises a drive unit, a rotor and a transmission interposed between the drive unit and the rotor; the transmission comprises a gear; the gear, in turn, comprises a main body rotatable about a first axis and a plurality of first teeth projecting in a cantilever fashion from the main body; the gear comprises a first pair of first rings axially opposite to each other and cooperating with the gear so as to exert a radial force on the gear.

A hover-capable aircraft is described that comprises a drive unit, a rotor and a transmission interposed between the drive unit and the rotor; the transmission comprises a gear; the gear, in turn, comprises a main body rotatable about a first axis and a plurality of first teeth projecting in a cantilever fashion from the main body; the gear comprises a first pair of first rings axially opposite to each other and cooperating with the gear so as to exert a radial force on the gear.

An apparatus and a method of retaining a bearing assembly having a bore to a shaft received within the bore, the method comprising physically limiting the axial movement of the bearing assembly on the shaft by a retainer mounted to an end of the shaft and having a portion extending radially beyond the shaft and into an axial path of the bearing assembly.

An apparatus and a method of retaining a bearing assembly having a bore to a shaft received within the bore, the method comprising physically limiting the axial movement of the bearing assembly on the shaft by a retainer mounted to an end of the shaft and having a portion extending radially beyond the shaft and into an axial path of the bearing assembly.