Applied Motion Products, Inc.

Donald J MaCleod

The present invention is an improved brushless direct current (DC) motor for use in various applications, including disk drives in data processing applications. The improved motor includes a rotor portion, containing a ring magnet with alternately radially polarized zones, a shaft portion, a stator portion, having a stator stack, and conducting windings and power and control circuitry. The stator stack includes a plurality of poles, each pole having a greater amount of magnetic material at one end than the other end. The structure of the stator stack poles urges the rotor portion to detent positions from which it is magnetically driven to rotation upon application of winding current and further urges rotation upon current application regardless of rotor position. The improved motor provides an economical, reliable starting rotation motor which functions in an unimpeded fashion at normal operating speeds and is adaptable as a rotational motion source for a variety of applications.

Brushless DC motor assembly with improved stator pole

A tachometer assembly is provided for use with electrical rotary magnetic motors. The assembly includes a conventional brushless DC motor (12) having a radially polarized main field ring magnet (24) forming the rotor (16) about a stator (18). The tachometer portion includes a commutator ring magnet (26) formed on one edge of the main field magnet (24) and an axially displaced circuit board (14) including one or more unbranched conducting traces (40). The commutator ring (26) includes a plurality of alternately axially polarized segments (27) which induce sinusoidal signals in the conductive traces (40) as the rotor (16) is rotated with respect to the circuit board (14). The tachometer assembly is utilized to generate rotational velocity and analog positional data for manipulation and control of the motor (12). The primary uses are in servo control mechanisms in the data processing and computer peripheral industries.

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Aptos, CA, United States of America

Donald J MaCleod