A ring gear assembly includes a ring gear, a gear box case, and a set of bolts. The ring gear includes a set of gear teeth inside the ring gear and arranged in a circle around the ring gear axis. The ring gear further includes a set of flanges arranged along at least one side of the ring gear. Each flange has a respective flange bolt hole therethrough, and each flange bolt hole has a respective bolt axis that is oriented perpendicular to the ring gear axis. The gear box case has a set of gear box bolt holes therethrough, each gear box bolt hole corresponding to a respective one of the flange bolt holes. Each of the bolts passes through a respective one of the gear box bolt holes and its corresponding flange bolt hole to fasten the ring gear to the gear box case.

A gearbox includes a sun gear, a plurality of planetary gears meshed with the sun gear, a rotating frame supporting the planetary gears, and a housing with an internal ring gear meshed with the planetary gears. The planetary gears include a first gear and a second gear coaxially connected to each other along an axial direction and rotating synchronously, the first gear meshed with the sun gear, and the second gear meshed with the internal ring gear of the housing. The rotating frame received in the housing has an upper frame and a lower frame with a central hole, each of the plurality of planetary gears is arranged between the upper frame and the lower frame by a mounting pin, the lower frame is supported by a flange connected to the housing, the sun gear is driven to rotate so as to operate the rotating frame. The gearbox of the present disclosure has low vibration and low noise.

A gear device includes an external gear, and an internal gear that meshes with the external gear. The external gear is formed of metal. The internal gear is formed of a carbon fiber reinforced resin.

Disclosed herein are actuator, planetary-gear apparatus, and structural-unit embodiments configured to reduce noise and vibration caused by operation of planetary gears. An embodiment may include a ring gear having an outer peripheral surface that extends in the axial direction. A first raised portion may be formed on said outer peripheral surface; and a housing having an inner peripheral surface that is provided facing, and with a gap from, the outer peripheral surface of the ring gear. A second raised portion may be formed on said inner peripheral surface. Movement of the ring gear in the circumferential direction is limited by linear contact or point contact between the first raised portion and the second raised portion, for example. The outer peripheral surface and/or the inner peripheral surface may be a surface of a crowned shape that is bowed in the outer radial direction, according to some further embodiments.

A method of manufacturing a mechanical part of the present invention includes a first process of forming, by performing a folding processing to an end portion of the material, a portion to be processed having a structure, in which a plurality of layers respectively having a thickness corresponding to a plate thickness of a material overlap each other, in the material such that a plate thickness direction of the layer is orthogonal to a plate thickness direction of the material; and a second process of changing, by performing a forging processing to the portion to be processed, a shape of the portion to be processed to a target shape while press-welding the layers of the portion to be processed to each other by plastic deformation.

There is provided a method of forming a ring gear, including providing a tube having an inner surface comprising gear teeth, the tube being a hollow tube formed by extrusion. The method also includes inserting a shaping tool into the tube, the shaping tool having tool teeth to mate with the gear teeth, and extended and retracted configurations. The shaping tool may be inserted into the tube in its retracted configuration. Moreover, the method includes extending the shaping tool into its extended configuration to cause the tool teeth to mate with the gear teeth and to exert a radially outward force on the tube. Furthermore, the method includes fixing a shape of an outer perimeter of the tube, retracting the shaping tool into its retracted configuration to reduce the radially outward force exerted by the shaping tool on the tube, and removing the shaping tool from the tube.

A planetary gear device includes: a housing cover disposed at one end portion of a housing in an axis direction, the housing being configured to house a sun gear and a planetary gear inside the housing; and a carrier cover disposed next to the housing cover in the axial direction in the inside, and configured to support a shaft of the planetary gear from one end portion side in the axial direction. One opposing part of a pair of opposing parts opposite to each other in the housing cover and the carrier cover includes a cone-shaped part whose diameter varies in the axial direction, and the other opposing part of the pair of opposing parts includes a sliding part configured to slide on a peripheral surface of the cone-shaped part with a same axis as an axis of the cone-shaped part.

In a wobble removal shaft coupling device including a wobble removal gear having an internal gear with a first central axial line and an external gear meshing with the wobble removal gear and having a second central axial line. The first and second central axial lines are in parallel with and offset from each other, and the external gear teeth are identical in number to the internal gear teeth of the wobble removal gear. At least one of the two sets of the gear teeth are resiliently deformable in a circumferential and/or radial direction so as to allow the two gears to be meshing with each other while permitting an eccentric wobbling movement of the external gear relative to the internal gear without requiring a play or a sliding engagement. The wobble removal shaft coupling device can be incorporated in a hypocycloid reduction gear device.

A configurable gear system that includes a set of gear segments; each gear segment of the set of gear segments including a base structure, a gearing surface connected to the base structure and extended along at least one face, and two segment connectors at opposing sides of the gearing surface; and wherein at least a subset of the gear segments interconnect through the gear connector interface into a gearing configuration.

A ring gear for an epicyclic or planetary reduction gear of a turbomachine, in particular of an aircraft, said ring gear extending about an axis X and comprising first and second coaxial annular elements and comprising, respectively, two inner annular toothing sets of different orientation, each of said toothing sets having a pitch diameter and a median plane substantially perpendicular to said axis and with an intersection point designated Y in an axial cross-section of the ring gear, said first and second annular elements further comprising, respectively, first and second radially outer annular flanges for attaching said first and second elements to each other, wherein each of said first and second flanges comprises a peripheral portion extending in a plane that is angled with respect to said axis X and that passes substantially through said intersection point Y.