Integral coaxial commutation and rotor magnets and apparatus and method for making same
First Claim
1. An integral annualr field and commutation magnet for a brushless DC motor formed on a single piece of permanently magnetized material and including a first annular field magnet portion at a first location and a second annular commutation magnet portion at a second location axially displaced from the first location, said field magnet portion having magnetized and unmagnetized sectors, said unmagnetized sectors being substantially unmagnetized portions of the magnetic material of said piece, being adjacent to magnetized sectors of the field magnet portion and integral therewith and having a substantial angular length.
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Abstract
An integral field and commutation magnet for use in DC brushless motor has both commutation and field magnet portions. Magnetized segments in both the field and commutation portions have oppositely oriented magnetic fields in the outward radial direction. An apparatus and method for making the one piece integral field and commutation magnet employ a fixture with a current conductor associated with magnetic flux paths corresponding to the segments of the commutation and field magnet portions to magnetize a single piece of permanently magnetizable material.
28 Citations
12 Claims
- 1. An integral annualr field and commutation magnet for a brushless DC motor formed on a single piece of permanently magnetized material and including a first annular field magnet portion at a first location and a second annular commutation magnet portion at a second location axially displaced from the first location, said field magnet portion having magnetized and unmagnetized sectors, said unmagnetized sectors being substantially unmagnetized portions of the magnetic material of said piece, being adjacent to magnetized sectors of the field magnet portion and integral therewith and having a substantial angular length.
- 9. An integral annular field and commutation magnet for a brushless DC motor having integral annular field and commutation portions at axially displaced first and second locations, said commutation portion comprising integral alternating oppositely radially magnetized commutation magnet sectors in close succession around the annular commutation magnet portion and the field magnet portion comprising integral oppositely radially magnetized field magnet sectors and integral substantially unmagnetized sectors of substantial angular length angularly adjacent radially magnetized sectors in the field magnet portion and defining null sectors.
Specification