Permanent magnet segment for use with a BLDC motor assembly

摘要

A BLDC electric motor assembly (24) includes a rotor (42) having a plurality of magnet segments (50) securely retained thereabout by an annular ring (68) which is shrunk in situ in an electromagnetic forming operation. The magnet segments (50) are formed with tongues (62, 64) on their upper and lower ends (56, 58). One tongue (64) seats in a retaining pocket (48) molded on the rotor shaft (40), whereas the other tongue (62) provides a ledge into which the ring (68) seats. After the magnet forming operation, wherein the ring (68) is shrunk, the outer surface of the ring (68) is flush with the outer surfaces (54) of the magnet segments (50).

主权项

1. A permanent magnet segment of the type used in an array of permanent magnet segments supported by an annular ring on a rotor in a brushless direct current (BLDC) electric motor assembly, said permanent magnet segment comprising:
an inner surface; a convex, semi-cylindrical outer surface; an upper end; a lower end spaced longitudinally from said upper end; opposing, generally parallel side edges extending longitudinally between said upper and lower ends; a first tongue adjacent said upper end sized and shaped for receiving an annular ring member adjacent to the outer surface of the permanent magnet segment; and a second tongue adjacent said lower end that is sized and shaped to be retained by a retaining pocket of a BLDC electric motor assembly; wherein the permanent magnet segment is one of an array of permanent magnet segments, wherein each of the array of permanent magnet segments is arranged so that the annular ring member loosely encircles the array of permanent magnet segments during a process for assembling the BLDC electric motor assembly, and wherein the annular ring member shrinks in size during the process for assembling the BLDC electric motor assembly.