An apparatus and method for reducing edge contact stress concentrations in a press-fit. The apparatus and method of the present disclosure specifically provide for a press-fit collar having a channel circumscribing a collar axis. The channel having an asymmetrical cross-sectional profile in a radial face. The asymmetrical cross-sectional profile being configured to reduce an edge contact pressure.

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 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 planetary transmission (2) includes a stepped planetary gear (24), or planetary gears, which are connected to each other, that is/are disposed radially between a first shaft (6) and axially-adjacent first and second ring gears (12, 16). The stepped planetary gear, or connected planetary gears, include(s) a first gearing region (26) that meshes with a sun gear (8) on the first shaft (6) and the first ring gear (12), as well as a helically-toothed second gearing region (28) that meshes with the second ring gear (16). A cylindrical support region (32) is coaxially provided on/around the first shaft. The stepped planetary gear or the connected planetary gears is/are supported on the cylindrical support region of the first shaft by the outer circumferential surface of the second gearing region. The second gearing region lies on the addendum circle of the second gearing region.

Provided is a friction transmission device including an input raceway ring, a planetary rolling element that is disposed around a rotation axis of the input raceway ring and comes into contact with the input raceway ring; an output raceway ring that comes into contact with the planetary rolling element and is connected to an output shaft, and a first support raceway ring and a second support raceway ring that come into contact with the planetary rolling element. A quadrangle is formed by extension lines of normal vectors at contact points between the planetary rolling element and the respective raceway rings.

A torque transfer device has plural planets arranged for planetary rotation about one or more sun gears and within one or more ring gears. Each planet includes at least one planetary gear set comprising plural planetary gears connected to rotate together, but having a different diameter to form a differential gear system. To improve load sharing, the plural planetary gears of each planetary gear set may have a different helical angle, the plural planetary gear sets being axially movable with respect to one another. Alternatively or in addition, the planetary gears may be made flexible with respect to radial forces.

A wind turbine gearbox, in particular planetary gearbox, has at least one gear which is mounted on an axle, wherein a sliding surface is arranged between the gear and the axle. The sliding surface is arranged on at least one layer of a deposition welded material made from a sliding bearing material. Furthermore, a method produces the wind turbine gearbox.

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.