D.C. BRUSHLESS MOTOR WITH MINIMIZED NET RADIAL FORCES AND LOW COGGING TORQUE

摘要

A ten pole/twelve slot brushless DC motor for a disk drive spindle includes a base; a cylindrical rotor structure rotating relative to the base and a generally symmetrically slotted stator structure fixed about an axis of rotation. The rotor structure includes a permanent magnet ring structure (56) defining ten permanently magnetized alternating north-south magnet segments (56a-56j). The stator structure includes a ferromagnetic core (60) defining twelve slots (65) between twelve stator poles (64). Coils of insulated wire are wound around the stator poles in one of a plurality of winding patterns and connected into a series of phases, e.g. three phases.