A gas turbine engine comprises a gearbox comprising a sun gear, an annulus gear, a plurality of planet gears and a carrier. Each planet gear is rotatably mounted in the carrier by a bearing. The sun gear meshes with the planet gears and the planet gears mesh with the annulus gear. The sun gear, the planet gears and the annulus gear comprise helical gear teeth. The annulus gear is secured to a surrounding structure by a radially extending member. A face of the flange nearest the middle of the annulus gear is axially spaced from the middle of the annulus gear by a first distance. The reference diameter of the annulus gear is radially spaced from a point at which the radially extending member is secured to the surrounding structure by a second distance. The ratio of first distance to second distance is between and including 0.5 and 1.2 such that misalignment between the annulus gear and the planet gears is reduced to minimise vibrations, noise, stress and wear of the gearbox.

A gas turbine engine comprises a gearbox comprising a sun gear, an annulus gear, a plurality of planet gears and a carrier. Each planet gear is rotatably mounted in the carrier by a bearing. The sun gear meshes with the planet gears and the planet gears mesh with the annulus gear. The sun gear, the planet gears and the annulus gear comprise helical gear teeth. The annulus gear is secured to a surrounding structure by a radially extending member. A face of the flange nearest the middle of the annulus gear is axially spaced from the middle of the annulus gear by a first distance. The reference diameter of the annulus gear is radially spaced from a point at which the radially extending member is secured to the surrounding structure by a second distance. The ratio of first distance to second distance is between and including 0.5 and 1.2 such that misalignment between the annulus gear and the planet gears is reduced to minimise vibrations, noise, stress and wear of the gearbox.

A cycloid speed reducer has a housing for accommodating a piece of equipment. Outer pins in meshing engagement with cycloid gears of a reduction gear portion are incorporated into the housing as a sliding bearing. A lubrication ring for lubricating the outer pins is slidably incorporated into the housing. The outer pins are lubricated by the outer pin lubricating ring. Inner pins are lubricated by a lubricating ring. The pair of cycloid gears are lubricated via the outer pins and the inner pins. As a result, friction between components is reduced, whereby frictional resistance decreases and durability is enhanced. In addition, the cycloid speed reducer can be manufactured as a small, compact unit.

A cycloid speed reducer has a housing for accommodating a piece of equipment. Outer pins in meshing engagement with cycloid gears of a reduction gear portion are incorporated into the housing as a sliding bearing. A lubrication ring for lubricating the outer pins is slidably incorporated into the housing. The outer pins are lubricated by the outer pin lubricating ring. Inner pins are lubricated by a lubricating ring. The pair of cycloid gears are lubricated via the outer pins and the inner pins. As a result, friction between components is reduced, whereby frictional resistance decreases and durability is enhanced. In addition, the cycloid speed reducer can be manufactured as a small, compact unit.

A transmission comprising at least one rim 1 and at least one wheel 2. An outside surface of the wheel 2 is adapted to engage with an inside surface of the rim 1. The wheel 2 is rotatable about a first axis B and the rim 2 is rotatable about a second axis A. The second axis A is at a distance from the first axis B. The inside surface of the rim 1 has a cyclic polygonal shape with an angle between each adjoining side 4 of the polygon being greater than 90?. The outer surface of the wheel 2 has a cyclic polygonal shape with an angle between each adjoining side 6 of the polygon being greater than 90?. Each side 6 of the wheel 2 engaging with a side 4 of the rim 1 of equal length during rotation of said transmission.

A ring gear for an aircraft mechanical gearbox, the ring gear having an annular shape about an axis and having an internal toothing at its internal periphery, an external annular flange or splines at its external periphery, and an annular web extending between the internal toothing and the external flange or splines. The web can include an annular row of arms which are distributed about the axis, these arms connecting the internal toothing to the external flange or splines and being formed in a single piece with the internal toothing and the external flange or splines.

A ring gear for an aircraft mechanical gearbox, the ring gear having an annular shape about an axis and having an internal toothing at its internal periphery, an external annular flange or splines at its external periphery, and an annular web extending between the internal toothing and the external flange or splines. The web can include an annular row of arms which are distributed about the axis, these arms connecting the internal toothing to the external flange or splines and being formed in a single piece with the internal toothing and the external flange or splines.

A pinion cage for supporting at least one spiral gear planet wheel in a spiral gear planetary gear train for an adjustment device for adjusting two structural components which can be adjusted relative to one another, wherein the spiral gear planet wheel comprises a planet wheel axle which comprises a first axial section extending over the spiral gear planet wheel and comprises a second axial section extending over the spiral gear planet wheel, and the pinion cage comprises a tubular base body which defines a pinion cage axis, at least one perforation arranged in the base body and penetrating through it, a first support section starting from the perforation, a second support section starting from the perforation, wherein the first and the second support sections are constructed for rotatably receiving the first and the second axial sections and are arranged in such a manner that the planet wheel axle runs in a twisted manner to the pinion cage axis if the axial sections are received in the support sections, and the pinion cage comprises a first fixing means connected to the base body for fixing the first axial section in the base body and a spiral gear planetary gear train with such a pinion cage and to an engine transmission unit with such a spiral gear planetary gear train.

A pinion cage for supporting at least one spiral gear planet wheel in a spiral gear planetary gear train for an adjustment device for adjusting two structural components which can be adjusted relative to one another, wherein the spiral gear planet wheel comprises a planet wheel axle which comprises a first axial section extending over the spiral gear planet wheel and comprises a second axial section extending over the spiral gear planet wheel, and the pinion cage comprises a tubular base body which defines a pinion cage axis, at least one perforation arranged in the base body and penetrating through it, a first support section starting from the perforation, a second support section starting from the perforation, wherein the first and the second support sections are constructed for rotatably receiving the first and the second axial sections and are arranged in such a manner that the planet wheel axle runs in a twisted manner to the pinion cage axis if the axial sections are received in the support sections, and the pinion cage comprises a first fixing means connected to the base body for fixing the first axial section in the base body and a spiral gear planetary gear train with such a pinion cage and to an engine transmission unit with such a spiral gear planetary gear train.

A reaction arm for use with a torque generating device, the reaction arm including a reaction bar, and a body portion having a first internal diameter, and having formed on an internal surface thereof a female spline having a second internal diameter and a guide bushing having a third internal diameter, the first, second, and third internal diameter being distinctly sized.