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US 4,048,531 AGranted
Variable reluctance stepper motor
AssigneeThe Singer Company
InventorsKenneth G. Buess, Murray Hefter
Life of this patent
Estimating the term…
Abstract
A variable reluctance stepper motor includes an energizable first stator cooperative with a first rotor for imparting incremental motion to the rotor and a second stator generating a permanent magnetic field and a second rotor cooperative therewith to restrain the rotor from drift rotation upon deenergization of the first stator. The second stator-second rotor combination defines positions of minimum magnetic reluctance radially angularly coincident with those provided by the first stator-first rotor combination. A lead screw is displaced rectilinearly to provide a linear output according with rotor shaft rotation.
Claims6
A variable reluctance stepper motor comprising:
- a. a first stator having a plurality of poles, with said poles energizable to generate and selectively rotate a magnetic field, including means for energization comprising a first winding encircling each of said poles and first circuit means for providing plural series circuits, each series circuit including therein a distinct group of such first windings, said first stator generating an incrementally rotating magnetic field upon sequential energization of said series circuits;
- b. a rotor shaft;
- c. a first rotor having a second number of poles different from the number of poles in said first stator, said first rotor supported by said shaft in radially spaced relation to said first stator for imparting rotation to said shaft in accordance with rotation of said magnetic field, said first stator and said first rotor together defining a predetermined number of rotational positions for said first rotor where minimum magnetic reluctance exists between said first stator and said first rotor;
- d. a second stator having a third number of poles;
- e. a second rotor supported by said shaft in radially spaced relation to said second stator, said second rotor having a fourth number of poles different from said third number of poles with the poles of said rotor and said stator defining a further number of rotational positions for said second rotor wherein a minimum magnetic reluctance exists between said second stator and said second rotor, said further rotational position number being equal to or an integral multiple of said predetermined rotational position number;
- and
- f. means associated with said second stator and said second rotor for generating a fixed magnetic field for restraining rotation of said rotor shaft from one of said further predetermined number of rotational positions upon de-energization of said first stator.
4 more elements
A variable reluctance stepper motor comprising;
- a. a first stator having a plurality of poles, with said poles energizable to generate and selectively rotate a magnetic field;
- b. a rotor shaft;
- c. a first rotor having a second number of poles different from the number of poles in said first stator, said first rotor supported by said shaft in radially spaced relation to said first stator for imparting rotation to said shaft in accordance with rotation of said magnetic field, said first stator and said first rotor together defining a predetermined number of rotational positions for said first rotor where minimum magnetic reluctance exists between said first stator and said first rotor;
- d. a second stator having a third number of poles;
- e. a second rotor supported by said shaft in radially spaced relation to said second stator, said second rotor having a fourth number of poles different from said third number of poles with the poles of said rotor and said stator defining a further number of rotational positions for said second rotor wherein a minimum magnetic reluctance exists between said second stator and said second rotor, said further rotational position number being equal to or an integral multiple of said predetermined rotational position number, a plurality of windings, each winding encircling one of said second stator poles, said second rotor including a plurality of teeth extending radially relative to said rotor shaft, each of said teeth defining one of said second rotor poles, and inducing signals in said winding of respectively different character upon respective clockwise and counterclockwise rotation of said rotor shaft;
- and
- f. means associated with said second stator and said second rotor for generating a fixed magnetic field for restraining rotation of said rotor shaft from one of said further predetermined number of rotational positions upon de-energization of said first stator.
4 more elements
A variable reluctance stepper motor comprising;
- a. a first stator having a plurality of poles, with said poles energizable to generate and selectively rotate a magnetic field;
- b. a rotor shaft defining a hollow interior in part threaded, said motor further including an exteriorly threaded shaft disposed in said rotor shaft interior in engagement with said threaded part thereof and displaced rectilinearly upon rotation of said rotor shaft;
- c. a first rotor having a second number of poles different from the number of poles in said first stator, said first rotor supported by said shaft in radially spaced relation to said first stator for imparting rotation to said shaft in accordance with rotation of said magnetic field, said first stator and said first rotor together defining a predetermined number of rotational positions for said first rotor where minimum magnetic reluctance exists between said first stator and said first rotor;
- d. a second stator having a third number of poles;
- e. a second rotor supported by said shaft in radially spaced relation to said second stator, said second rotor having a fourth number of poles different from said third number of poles with the poles of said rotor and said stator defining a further number of rotational positions for said second rotor wherein a minimum magnetic reluctance exists between said second stator and said second rotor, said further rotational position number being equal to or an integral multiple of said predetermined rotational position number;
- and
- f. means associated with said second stator and said second rotor for generating a fixed magnetic field for restraining rotation of said rotor shaft from one of said further predetermined number of rotational positions upon de-energization of said first stator.
4 more elements
A variable reluctance stepper motor comprising;
- a. a first stator having a plurality of poles, with said poles energizable to generate and selectively rotate a magnetic field;
- b. a rotor shaft;
- c. first rotor having a second number of poles different from the number of poles in said first stator, said first rotor supported by said shaft in radially spaced relation to said first stator for imparting rotation to said shaft in accordance with rotation of said magnetic field, said first stator and said first rotor together defining a predetermined number of rotational positions for said first rotor where minimum magnetic reluctance exists between said first stator and said first rotor;
- d. a second stator having a third number of poles;
- e. a second rotor supported by said shaft in radially spaced relation to said second stator, said second rotor having a fourth number of poles different from said third number of poles with the poles of said rotor and said stator defining a further number of rotational positions for said second rotor wherein a minimum magnetic reluctance exists between said second stator and said second rotor, said further rotational position number being equal to or an integral multiple of said predetermined rotational position number;
- f. means associated with said second stator and said second rotor for generating a fixed magnetic field for restraining rotation of said rotor shaft from one of said further predetermined number of rotational positions upon de-energization of said first stator;
- and
- g. a plurality of windings, each winding encircling one of said second stator poles, the windings encircling each of said second stator poles all connected in series with each other.
5 more elements
Dependencies are inferred from the claim text.