05552682 is referenced by 17 patents and cites 7 patents.

A signal of one pulse per turn of a motor is obtained by using an m-phase driving coil (L) to be reciprocally electrified in positive and negative directions; a driving magnet which faces the driving coil (L), whose driving magnetic poles S and N are alternately polarized, and which rotates together with a rotary shaft; homopolar position detecting magnetic element (N+) formed on at least one of the driving magnetic poles (N and S); magnetic detectors arranged so as to face the driving magnet to detect the magnetic fields of both the driving magnetic poles (N and S) and the position detecting magnetic element (N+); a brushless-motor driving circuit for supplying a driving current to the driving coil (L) in accordance with signals provided from magnetic detectors; and a synthesizing element for synthesizing a rotational position signal from signals provided from the magnetic detectors, a counter electromotive voltage waveform of the driving coil (L), and a reference voltage (COM). Therefore, the component cost can be decreased because the existing PG sensor and PG magnet are unnecessary, and also the manufacturing cost can be decreased because it is unnecessary to install the PG magnet and mount the PG sensor on a board. Moreover, the board can be downsized because space for the PG sensor and PG-sensor wiring space is unnecessary.

Device for detecting rotational position of brushless motor
Application Number
Publication Number
Application Date
March 6, 1995
Publication Date
September 3, 1996
Isao Ushikoshi
McAulay Fisher Nissen Goldberg & Kiel
Sankyo Seiki Mfg
H02P 6/16
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