A speed reducer comprises a transmission shaft, an eccentric wheel, a first wheel assembly, a rotating wheel and a second wheel assembly. The first wheel assembly comprises a first wheel disc and at least one first roller. The at least one first roller is disposed on the inner wall of first wheel disc. The rotating wheel comprises a main body comprising an outer ring structure and a concave structure. The outer ring structure comprises at least one first tooth. The at least one first tooth is in contact with the corresponding first roller. At least one second roller is disposed within the concave structure. The second wheel assembly comprises a second wheel disc and at least one second tooth. The at least one second tooth is disposed on an outer periphery of the second wheel assembly. The at least one second tooth is in contact with the corresponding second roller.

A cycloid speed reducer includes an input shaft, a rolling assembly, first and second cycloid discs, a crankshaft and an output disc. The first and second cycloid discs are disposed around the input shaft and driven by the input shaft. The first and second cycloid discs are located at two opposite sides of the rolling assembly, respectively. The crankshaft includes first and second eccentric ends and first and second concentric ends integrally formed as a one-piece structure and arranged sequentially. The first and second eccentric ends are linked with the first and second cycloid discs respectively. An eccentricity value is between any neighboring two of the concentric and eccentric ends. The diameters of all the concentric and eccentric ends are equal. The output disc is linked with the first or second concentric end. The output disc is a power output end of the cycloid speed reducer.

A cycloid speed reducer includes an input shaft, a rolling assembly, first and second cycloid discs, a crankshaft and an output disc. The first and second cycloid discs are disposed around the input shaft and driven by the input shaft. The first and second cycloid discs are located at two opposite sides of the rolling assembly, respectively. The crankshaft includes first and second eccentric ends and first and second concentric ends integrally formed as a one-piece structure and arranged sequentially. The first and second eccentric ends are linked with the first and second cycloid discs respectively. An eccentricity value is between any neighboring two of the concentric and eccentric ends. The diameters of all the concentric and eccentric ends are equal. The output disc is linked with the first or second concentric end. The output disc is a power output end of the cycloid speed reducer.

The p recessional gear transmission comprises a body, a satellite wheel with two bevel gear rings driven by a crankshaft in sphero-spatial motion around a fixed point, two central bevel wheels, one immobile fixed in the body and the other mobile mounted on a driven shaft. The teeth of the gear rings have a circular arc flank profile, those of the central bevel wheels are variable curvilinear. The configuration of the parameters of angles, the number of teeth, the ratio of the numbers of teeth of the mating wheels in the gears and the radius of the circular arc of the teeth profile of the gear rings determines the geometry and the kinematics of the contact of the teeth, the degree of frontal overlap, expressed by the number of simultaneously engaged pairs of teeth and defines the pressure angle between the mating flanks.

The p recessional gear transmission comprises a body, a satellite wheel with two bevel gear rings driven by a crankshaft in sphero-spatial motion around a fixed point, two central bevel wheels, one immobile fixed in the body and the other mobile mounted on a driven shaft. The teeth of the gear rings have a circular arc flank profile, those of the central bevel wheels are variable curvilinear. The configuration of the parameters of angles, the number of teeth, the ratio of the numbers of teeth of the mating wheels in the gears and the radius of the circular arc of the teeth profile of the gear rings determines the geometry and the kinematics of the contact of the teeth, the degree of frontal overlap, expressed by the number of simultaneously engaged pairs of teeth and defines the pressure angle between the mating flanks.

A mechanical gearbox for an aircraft turbomachine includes a sun gear having an axis (X) of rotation, a ring gear around the sun gear, and planet gears meshed with the sun gear and the ring gear. Each planet gear has a first toothing meshed with the sun gear and a second loathing meshed with the ring gear. The first toothing includes a series of upstream teeth and a series of downstream teeth located on either side of a plane (H) perpendicular to the axis (X) of rotation of the sun gear. The second toothing includes a series of upstream teeth and a series of downstream teeth located on either side of the plane (H) and separated from one another by the first toothing, these teeth being parallel to one another and to the axis (Y) of rotation of the planet gear.

A mechanical gearbox for an aircraft turbomachine includes a sun gear having an axis (X) of rotation, a ring gear around the sun gear, and planet gears meshed with the sun gear and the ring gear. Each planet gear has a first toothing meshed with the sun gear and a second loathing meshed with the ring gear. The first toothing includes a series of upstream teeth and a series of downstream teeth located on either side of a plane (H) perpendicular to the axis (X) of rotation of the sun gear. The second toothing includes a series of upstream teeth and a series of downstream teeth located on either side of the plane (H) and separated from one another by the first toothing, these teeth being parallel to one another and to the axis (Y) of rotation of the planet gear.

A speed reducer comprises a transmission shaft, an eccentric wheel, a first wheel assembly, a rotating wheel and a second wheel assembly. The first wheel assembly comprises a first wheel disc and at least one first roller. The at least one first roller is disposed on the inner wall of first wheel disc. The rotating wheel comprises a main body comprising an outer ring structure and a concave structure. The outer ring structure comprises at least one first tooth. The at least one first tooth is in contact with the corresponding first roller. At least one second roller is disposed within the concave structure. The second wheel assembly comprises a second wheel disc and at least one second tooth. The at least one second tooth is disposed on an outer periphery of the second wheel assembly. The at least one second tooth is in contact with the corresponding second roller.

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 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.