Patent ID: 8436501
Filing Date: 2013-05-07
Classification: F16C,H02K,Y10T

Abstract:
1. A manufacturing method of a rotor for an electric gear motor, wherein the rotor includes a rotatable shaft and a bearing, and the bearing is fixed to the rotatable shaft at an axial location between a worm portion, in which a worm is formed, and a core fixation portion, which is adapted to securely hold a rotor core of the rotor therearound, the manufacturing method comprising: shaping a shaft preform, which is made of metal and has a generally constant outer diameter along a generally entire length of the shaft preform, by cold forging to form the rotatable shaft, so that a small diameter portion, which has an outer diameter smaller than an outer diameter of the core fixation portion, is cold-forged on the shaft preform, and a flange, which is configured into an annular form and has an outer diameter larger than the outer diameter of the core fixation portion, is cold-forged on the shaft preform at the axial location between the small diameter portion and the core fixation portion; forming the worm in the small diameter portion to produce the worm portion having the worm by thread rolling after the shaping of the shaft preform; positioning the bearing relative to the rotatable shaft by inserting the bearing over the rotatable shaft until the bearing contacts the flange after the forming of the worm; and fixing the bearing to the rotatable shaft after the positioning of the bearing such that a swaged portion is formed in an outer peripheral portion of the rotatable shaft on an opposite axial side of the bearing, which is axially opposite from the flange, by swaging a corresponding part of the outer peripheral portion of the rotatable shaft such that the corresponding part of the outer peripheral portion of the rotatable shaft is radially outwardly bulged to form the swaged portion, and the swaged portion is axially pressed against the bearing to axially securely clamp the bearing between the swaged portion and the flange.