Proportional rotary torquer

• US 20060214614A1
• Filed: 04/02/2004
• Published: 09/28/2006
• Est. Priority Date: 04/03/2003
• Status: Abandoned Application

• Current Assignee: Minebea Company Limited (MinebeaMitsumi Inc.)
• Original Assignee: Minebea Company Limited (MinebeaMitsumi Inc.)
• Inventors: Zhao, Shen
• Application Number:
  US10/551,533
• Publication Number:
  US 20060214614A1
• Time in Patent Office: Days
• US Class Current: 318/432
• CPC Class Codes: H02K 26/00 Machines adapted to function as torque motors, i.e. to exert a torque when stalled

Abstract

Salient poles 3a formed at a rotor core 3 are structured such that their facing surfaces facing permanent magnets 1a and 1b are formed in the shapes of circular arcs of which the radii at the circumferential center portion and at the circumferential end portions are different from each other. The angle between the line connecting one of the circumferential outlines of one of the salient poles 3a and the rotation center of the rotor core 3 and the line connecting the other circumferential outline of the same salient pole 3a and the rotation center of the rotor core 3 is not less than 100 degrees. Permanent magnets 1a and 1b are structured such that the radial thickness B of each circumferential end portion is from 90% to 95% of the radial thickness A of each circumferential center portion, so as to have circular arc surfaces of which center positions are different from each other. As a result, by supplying an electric current to the rotor coils, a constant electromagnetic torque is available within a relative angular displacement range of more than 90 degrees of the rotor and the stator, and the magnitude of electromagnetic torque is in proportion to the magnitude of the exciting current. When the exciting current is supplied in the direction opposite to that of the above current, the direction of the electromagnetic torque is opposite.

Claims

1. A proportional rotary torquer comprising:

a stator having plural permanent magnets; and

a rotor having a rotor core which plural salient poles are formed at, and one or more rotor coils are wound around;

wherein an electric current is supplied to the rotor coils, so that a relative angle position of the rotor and the stator is displaced;

wherein the permanent magnet has two circumferential end portions and one circumferential center portion, and the radial thickness of the circumferential end portion is from 90% to 95% of the radial thickness of the circumferential center portion;

wherein the distance from the radial outline of the center portion of the salient pole to the rotation center of the rotor core is not more than 99% of the distance from the radial outline of the circumferential end portion of the salient pole to the rotation center of the rotor core; and

wherein the angle between the line connecting one of the circumferential outlines of the salient pole and the rotation center of the rotor core and the line connecting the other circumferential outline of the same salient pole and the rotation center of the rotor core is not less than 100 degrees.

2. A proportional rotary torquer according to claim 1, wherein the proportional rotary torquer is structured such that:

the radial thickness of the permanent magnet at the circumferential end portions being smaller than the radial thickness of the permanent magnet at the circumferential center portion;

the distance from the radial outline of the center portion of the salient pole to the rotation center of the rotor core being smaller than the distance from the radial outline of the circumferential end portions of the salient pole to the rotation center of the rotor core; and

the angle between the line connecting one of circumferential outlines of the salient pole and the rotation center of the rotor core and the line connecting the other circumferential outline of the same salient pole and the rotation center of the rotor core being an obtuse angle.

3. A proportional rotary torquer according to claim 1, wherein the rotor core and the permanent magnet have facing surfaces facing each other, the facing surfaces of the rotor core and the permanent magnet formed in the shapes of the circular arc surfaces of which center positions are different from each other.

4. A proportional rotary torquer according to claim 1, wherein the permanent magnet has a facing surface facing the rotor core, the facing surface formed in the shape of an elliptical surface.

5. A proportional rotary torquer according to claim 1, wherein the permanent magnet has a facing surface facing the rotor core, the facing surface at the circumferential end portion formed in the shape of a flat-cut surface.

6. A proportional rotary torquer according to claim 1, wherein the rotor core has two facing surfaces respectively facing the two permanent magnets, each of the facing surfaces of the rotor core formed in the shapes of a plurality of circular arc surfaces of which center positions are different from each other.

7. A proportional rotary torquer according to claim 1, wherein the rotor core has two facing surfaces respectively facing the two permanent magnets, each of the facing surfaces formed in the shape of an elliptical surface.

8. A proportional rotary torquer according to claim 1, wherein the rotor core has two facing surfaces respectively facing the two permanent magnets, the facing surface at the circumferential end portion of the salient pole formed in the shape of a flat-cut surface.

9. A proportional rotary torquer according to claim 1, wherein the permanent magnet has two circumferential end portions, each of which has a non-magnetized region formed thereat.

10. A proportional rotary torquer according to claim 1, wherein the proportional rotary torquer further comprises one or more elastic members generating the torque at the magnitude proportional to the angular displacement of the rotor and in the direction opposite to the rotation direction of the rotor.