Patent ID: 7122929
Filing Date: 2006-10-17
Classification: G11B,H02K

Abstract:
1. A spindle motor for a disk driving device, comprising: a housing having an annular hole and a cylindrical projection portion formed integrally with the housing; a stator comprising a stack and coils wound around the stack, the stator is mounted on an outer circumference of the cylindrical projection portion of the housing to confront a magnet; a lead wire of the coils is connected to an electric supplying connector portion; and a rotor having a central hole and a downwardly depending flange at an outer periphery thereof, the magnet is disposed on an inner peripheral surface of the downwardly depending flange of the rotor, the rotor supported rotatably relative to the housing by a bearing means, the bearing means is a double row ball bearing and comprising a sleeve outer ring, a plurality of first balls, a plurality of second balls, an inner ring and a shaft, the sleeve outer ring having a pair of outer raceway grooves on an inner circumference surface of the sleeve outer ring, the shaft having a small diameter portion and a large diameter portion with an inner raceway groove on the outer circumference surface of the large diameter portion, the inner ring is fixed on the small diameter portion of the shaft, the first balls are disposed between one outer raceway groove of the sleeve outer ring and an inner raceway groove formed on an outer circumference surface of the inner ring, the second balls are disposed between another outer raceway groove of the sleeve outer ring and the inner raceway groove of the large diameter portion of the shaft, wherein the large diameter portion of the shaft is fitted in the annular hole of the housing, the sleeve outer ring is fitted in the central hole of the rotor, one end portion of the sleeve outer ring being located in the cylindrical projection portion and the housing and rotor are made of a super engineering plastic material and are unitarily formed by injection molding.