Permanent magnet motor having teeth with fingers

摘要

A permanent magnet-type stepping motor broadly includes: a movable member (e.g., a rotor) having a number of magnetic poles on a surface thereof, with adjacent poles being of opposite polarity, the number of poles being a function of a constant, the number of phases and a desired step interval; and a stationary member (e.g., a stator) having a number of equally-spaced teeth arranged to face toward said movable member surface, each of said teeth having a plurality of fingers arranged to face toward said movable member surface, the number of said teeth being a whole integer that is a function of a constant, the number of said poles, the number of said fingers on each stator tooth, and the number of phases.

主权项

1. A permanent magnet-type stepping motor having a motor driver, a movable member and a stationary member, comprising:
a number of circumferentially spaced magnetic poles on a surface of one of said members, with adjacent poles being of opposite polarity, the number of poles being a function of a constant, the number of phases and a desired step interval; said magnetic poles having a separation region between adjacent magnetic poles; a number of equally-spaced teeth on the other of said members, said teeth being arranged to face toward said one member surface, each of said teeth having a plurality of circumferentially spaced fingers arranged to face toward said one member surface, the number of said teeth being a whole integer that is a function of a constant, the number of said poles, the number of fingers on each stator tooth, and the number of phases; wherein said fingers are spaced from one another such that the fingers on any given tooth will align with poles of the same polarity; wherein said one member is a rotor having an outer surface, said other member is a stator, said desired step interval is a desired step angle, and said teeth are spaced circularly about said stator to face toward said rotor outer surface; wherein the number of said rotor poles is an even integer determined from the equation:step⁢⁢angle=(drive⁢⁢number)×360⁢°(no.⁢of⁢⁢phases)×(no.⁢of⁢⁢rotor⁢⁢poles)where the drive number is 1 for a bipolar drive and 2 for a unipolar drive; and
wherein the maximum number of stator teeth (m) per phase is determined by the equation:m≤int(no.⁢of⁢⁢rotor⁢⁢poles[2×(no.⁢of⁢⁢fingers⁢⁢per⁢⁢stator⁢⁢tooth)-1]×(no.⁢of⁢⁢phases)),where the expression, int(x), is the integer function that returns the integer portion of its argument (x).