An input gear assembly in which the input gear is coupled to the input shaft via a pair of spaced-apart pilot regions of the input shaft. One of the pilot regions is disposed adjacent to one of the bearings used, with the pilot region formed in or on the input shaft itself and engaging a corresponding internal surface of the input gear. Another of the pilot regions is formed in the inner bearing raceway of another of the bearings used, with the pilot region formed as an elongate portion of the inner bearing raceway of the input shaft and engaging another corresponding internal surface of the input gear. For manufacturing simplicity, this additional pilot region and the remainder of the elongate inner bearing raceway have the same material properties, surface treatment, straightness, and cylindricity. This arrangement prevents tilting of the input gear with respect to the input shaft and bearing shaft, thereby enhancing performance.

A transmission structure of a helicopter according to one aspect is a transmission structure that transmits power from a prime mover to a rotary wing in the helicopter. The transmission structure includes: a housing; an input shaft that transmits the power of the prime mover to a gear arranged in the housing; a bearing supporting the input shaft in the housing such that the input shaft is rotatable, the bearing including an annular inner ring that holds the input shaft, an annular outer ring that is arranged outside the inner ring in a radial direction and fixed to the housing, and rolling elements sandwiched between the inner ring and the outer ring; and a sleeve that is sandwiched between an inner peripheral surface of the inner ring and the input shaft and is lower in heat conductivity than the inner ring and the input shaft.

A magnetic geared rotary electric machine includes: a casing; a stator which includes a stator core, a coil, and a stator magnet provided inside the stator core; a first rotor which includes pole pieces provided inside the stator; a second rotor which includes a rotor core provided inside the first rotor and rotor magnets provided in the rotor core at intervals in a circumferential direction; movable bearings which are provided in the casing so as to be arranged at intervals in the circumferential direction and which come into contact with at least one of outer peripheral surfaces of the first rotor and the second rotor; and actuators which move the movable bearings in a direction included in a plane orthogonal to an axis.

A journal bearing comprising a first component and a second component, the first and second components being arranged to rotate relative to one another in normal use. The first component comprises a first body, a first layer forming a functional surface facing the second component, and a first subsurface layer between the body and the layer. The first subsurface layer is formed of a material having a first coefficient of thermal expansion in the radial direction, and the first body is formed of a material having a second coefficient of thermal expansion in the radial direction. The first coefficient of thermal expansion is lower than the second coefficient of thermal expansion.

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 carrier assembly has a pair of axially spaced-apart plates defining an axial gap therebetween. The plates have a plurality of planetary bores on a plurality of planetary axes. A plurality of planetary gear mount assemblies are disposed on the planetary axes and mounted within the planetary bores of the gear carrier. Each assembly comprises a journal bearing shaft having a pair of compliance grooves extending axially from opposed axial ends of the shaft. An inner cylindrical surface of each compliance groove defines a shaft mounting surface. A pair of collars is provided to assemble each journal bearing shaft to the carrier. Each collar has a mounting socket mating the shaft mounting surface and an external collar surface matching the planetary bore diameter.

A gas turbine engine comprises a gearbox comprising a sun gear, an annulus gear, a plurality of planet gears and a planet gear carrier. The sun gear meshes with the planet gears and the planet gears mesh with the annulus gear. Each planet gear is rotatably mounted in the planet gear carrier. The planet gear carrier comprises a plurality of axles arranged parallel to the axis of the gearbox. The axially spaced ends of each axle are secured to the planet gear carrier. Each planet gear is rotatably mounted on a corresponding one of the axles by a bearing arrangement. Each bearing arrangement comprises a journal bearing and a rolling element bearing and each planet gear is rotatably mounted on a journal bearing and each journal bearing is rotatably mounted on an axle by at least one rolling element bearing.

A gear unit for a motor vehicle having a drive shaft extending axially and mounted rotatably, and a worm gear shaft which cooperates with a worm gear wheel. A torque-transmitting coupling connects the drive shaft to one end of the worm gear shaft with the other end supported by a bearing. A pretension element loads the bearing and correspondingly the worm gear shaft so the worm gear shaft is biased or pressed against the worm gear wheel. The torque-transmitting coupling provides a suitable connection between the drive shaft and worm gear shaft.

A worm gear drive mechanism (1) having a housing (8), a rotatably mounted worm gear (4) and a worm shaft (2) rotatably mounted at at least one bearing point (7), wherein the bearing point (7) has a displacement element (10) for displacing the axial spacing (17) between the gear axis of rotation (6) of the worm gear (4) and the shaft axis of rotation (5) of the worm shaft (2).