Variable reluctance stepper motor
AssigneeKollmorgen Technologies Corporation
InventorLawrence W. Langley
Life of this patent
Estimating the term…
Abstract
A variable reluctance stepper motor including cooperating fixed and moving structures having tooth-like patterns of equal pitch but with the fixed and moving teeth having different lengths, measured in the direction of movement. The smaller teeth are divided into groups which are offset from one another by fractions of a tooth pitch to provide a bi-directional motor capable of being stepped from one position to the next with the teeth tending to produce force in the desired direction carrying essentially all of the flux and the teeth tending to produce force in the opposite direction carrying essentially no flux. Methods and techniques are also disclosed for fabricating tooth structures and bearing systems.
Claims16
A variable reluctance, bi-directional stepper motor comprising:
- a first member having a plurality of teeth, each of said teeth having both a pitch P and a width equal to P/2;
- and
- a second member moveable relative to said first member, said second member comprising two poles, each pole having two sets of teeth, each of said teeth having both a pitch P and a width equal to P/4, the sets of teeth in each pole being offset from each other by an amount equal to (n.+-.1/2)P, n being an integer, said poles being offset from each other by an amount equal to (m.+-.1/4)P, m being an integer, each of said poles having associated therewith a winding adapted for connection to a direct current source, said second member having associated therewith at least one magnet.
A linear, variable reluctance, bi-directional stepper motor comprising:
- a first cylindrical member having a plurality of regular helical teeth with grooves therebetween, each of said teeth having both a pitch P and a width equal to P/2;
- and
- a second cylindrical member surrounding at least a portion of said first member, said second member comprising two annular poles separated by an annular permanent magnet, each pole having two annular elements separated by an annular winding, adapted for connection to a direct current source, each element having a set of regular helical teeth with grooves therebetween, each of said teeth having both a pitch P and a width equal to P/4, the sets of teeth in each pole being offset longitudinally from each other by an amount equal to (n.+-.1/2)P, n being an integer, said poles being offset from each other in the longitudinal direction by an amount equal to (m.+-.1/4)P, m being an integer.
A disk, rotary, variable reluctance, bi-directional stepper motor comprising:
- a disk-shaped rotor mounted on a shaft and having a plurality of wedge-shaped, radially extending equally spaced teeth having an angular pitch P and an angular width equal to P/2;
- and
- a stator comprising two poles one disposed on each side of said rotor, each stator pole having two sets of wedge-shaped, radially extending, equally spaced teeth having an angular pitch P and an angular width equal to P/4, the locii of said sets of stator teeth describing circles having two different radii, the sets of teeth in each stator pole being offset from each other by an angular amount equal to (n.+-.1/2)P, n being an integer, the two stator poles being offset from each other by an angular amount equal to (m.+-.1/4)P, m being an integer, each stator pole also including an annular magnet and an annular winding adapted for connection to a direct current source.
A motor according to claim 13 wherein the magnet is a rare earth permanent magnet.
A cylindrical, rotary, variable bi-directional stepper motor comprising:
- a cylindrical rotor having a plurality of longitudinally extending teeth with grooves therebetween, said rotor teeth having an angular pitch P and an angular width equal to P/2;
- and
- a cylindrical stator surrounding said rotor, said stator having two annular poles separated by an annular magnet, each stator pole having two sets of equally spaced, longitudinally extending teeth having an angular pitch P and an angular width equal to P/4, the sets of teeth in each stator pole being offset from each other by an angular amount equal to (n.+-.1/2)P, n being an integer, the two stator poles being offset from each other by an angular amount equal to (m.+-.1/4)P, m being an integer, the sets of teeth in each stator pole being separated by an annular winding adapted for connection to a direct current source.
A variable reluctance, bi-directional stepper motor comprising:
- a first member having a plurality of teeth, each of said teething having both a pitch P and a width equal to P/2;
- and
- a second member moveable relative to said first member, said second member comprising two poles, each pole having two sets of teeth, each of said teeth having both a pitch P and a width equal to P/4, the sets of teeth in each pole being offset from each other by an amount equal to (n.+-.1/2)P, n being an integer, said poles being offset from each other by an amount equal to (m.+-.1/4)P, m being an integer, each of said poles having associated therewith a winding adapted for connection to a direct current source, said second member having associated therewith at least one permanent magnet.
Dependencies are inferred from the claim text.