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EP0032441A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Brushless D.C. motor and control circuit therefor

Assignee: Individual
•
Filing: 1981-01-09
•
Granted: —
•
Expires: 2001-01-09
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Abstract

Abstract A brushless d.c. motor comprises a multi-coil structure bonded to a soft iron magnetic shell (20) forming the stator of the motor. A rotor assembly (25) comprises at least a pair of permanent magnets (28) mounted on the rotor portion of the motor. Control circuitry (12) comprises sensor elements such as Hall Effect devices (30) mounted with the magnetic portion (32) thereof on the rotor shaft for rotation therewith and with stationary sensor portions (34), corresponding in number and angular location to the number of coils in the multi-coil structure. The control circuitry further comprises a programmed micro-processor (40) for analyzing the angular position of the rotating magnet assembly, for correlating the same with a required direction of rotation and for providing the proper commands to a solid state coil exciting circuit (44,45,46) to drive the coils of the multi-coil structure. The excitation of the stator coils is varied at the rate of twice the number of sensor elements (34) per revolution of the rotor (25). The motor assembly of the invention has a high torque per unit volume efficiency and a high work output per power input efficiency, comparable to the efficiencies of conventional D.C. brush motors.

Inventors

  • 👤 Howard F. Hendricks

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-28 13:26
CPC Classifications
H; H02; H02K; H02K29/00; H02K29/06; H02K29/08

Claims Analysis

Total Claims: 11
Claim 1
Independent Claim 106 words
A motor assembly comprising a brushless DC motor and control circuitry therefor, including a rotor mounting at least a pair of permanent magnets, a stator including a number of excitable coils and a rotor position sensing device including a plurality of sensor elements the output of each of which is dependent on the angular position of the rotor, characterized in that a logic decoding system (12) is provided for receiving output signals (50,51,52,53,54) from the sensors and controlling a coil exciting circuit (44,45,46) to vary the excitation of the stator coils at the rate of twice the number of sensor elements per revolution of the rotor.
Claim 2
Dependent Claim 106 words
A motor assembly comprising a brushless DC motor and control circuitry therefor, including a rotor mounting at least a pair of permanent magnets, a stator including a number of excitable coils and a rotor position sensing device including a plurality of sensor elements the output of each of which is dependent on the angular position of the rotor, characterized in that a logic decoding system (12) is provided for receiving output signals (50,51,52,53,54) from the sensors and controlling a coil exciting circuit (44,45,46) to vary the excitation of the stator coils at the rate of twice the number of sensor elements per revolution of the rotor.
Claim 3
Dependent Claim 25 words
A motor assembly according to claim 1, wherein each of the coils comprises series connected coil elements diametrically opposed to one another on the stator.
Claim 4
Dependent Claim 20 words
A motor assembly according to either preceding claim, wherein the coils are connected to one another in series aiding relationship.
Claim 5
Dependent Claim 26 words
A motor assembly according to any preceding claim, wherein the namber of excitable coil elements of the stator is twice the number of the sensor elements.
Claim 6
Dependent Claim 35 words
A motor assembly according to any preceding claim, further comprising signal inverting means (43) for inverting the output signals (50,51,52,53,54) from the sensors to the logic decoding system (12) for reversal of the rotor direction.
Claim 7
Dependent Claim 16 words
A motor assembly according to any preceding claim, wherein the rotor mounts four permanent magnets thereon.
Claim 8
Dependent Claim 14 words
A motor assembly according to claim 6, wherein the stator includes five excitable coils.
Claim 9
Dependent Claim 17 words
A motor assembly according to claim 7, wherein the rotor position sensing device includes five sensor elements.
Claim 10
Dependent Claim 27 words
A motor assembly according to any preceding claim, wherein the sensor elements are permanent magnets and the rotor position sensing device is a Hall Effect sensing device.
Claim 11
Dependent Claim 22 words
A motor assembly according to any preceding claim, wherein the coils of the stator are bonded to a soft iron magnetic shell.

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