Patent ID: 8684878
Filing Date: 2014-04-01
Classification: F16H

Abstract:
1. A speed reducer comprising a stationary housing, an internal gear supported by the housing and having a plurality of internal teeth on an inner periphery of the internal gear, an input shaft including an eccentric disk provided at one end portion of the input shaft and rotatable in the internal gear, an output shaft coaxial with the input shaft, a cage provided at an end portion of the output shaft facing the input shaft and rotatably disposed between the internal gear and the eccentric disk, said cage being formed with circumferentially equidistantly spaced apart pockets which are not equal in number to the internal teeth of the internal gear at a portion of the cage that is radially aligned with the eccentric disk, rollers received in the respective pockets and configured to mesh with the respective rollers one after another when the eccentric disk rotates such that when the input shaft rotates once, each roller moves in a circumferential direction by a distance equal to a circumferential dimension of one of the internal teeth, whereby the output shaft is rotated at a reduced speed, characterized in that the cage is formed with an annular recess at a corner between a radially inner surface of the cage and a closed end surface of the cage.