Patent ID: 8152676

Claim:
A speed change gear comprising: a housing that supports an input shaft and an output shaft rotatably about a common input/output axis, and that has a plurality of internal gears having different inside diameters on its inner peripheral surface; and a plurality of change gear units that are respectively arranged at locations of the housing in a direction along the input/output axis, at which the plurality of internal gears are formed, that are respectively in mesh with the plurality of internal gears, and that change the speed of rotation from the input shaft to the output shaft, wherein each of the change gear units includes a rotating member that is supported by the housing rotatably about the input/output axis, and that has one of a pin protruding in the direction along the input/output axis and an insertion hole in which the pin is inserted; an eccentric member that centers on an eccentric axis that is eccentric with respect to the input/output axis; and an annular oscillating member that is rotatably supported on an outer peripheral side of the eccentric member, that has an external gear which is formed on an outer peripheral surface and which is able to be in mesh with the internal gear and the other one of the pin and the insertion hole, and that oscillatingly rotates as the eccentric member rotates about the input/output axis, wherein the plurality of change gear units include one side change gear unit and the other side change gear unit that are next to each other, the eccentric member of the one side change gear unit is coupled to one of the input shaft and the output shaft, the rotating member of the one side change gear unit is coupled to the eccentric member of the other side change gear unit, the rotating member of the other side change gear unit is coupled to the other one of the input shaft and the output shaft, and the eccentric member of the other side change gear unit is integrally coupled to the rotating member of the one side change gear unit at a location eccentric in a radial direction of the rotating member of the one side change gear unit such that a radially outer peripheral surface of the rotating member of the one side change gear unit rotatably supports the eccentric member of the other side change gear unit.