Quick-action bistable polarized electromagnetic actuator

• US 7,898,122 B2
• Filed: 04/06/2006
• Issued: 03/01/2011
• Est. Priority Date: 04/06/2005
• Status: Active Grant

• Current Assignee: Moving Magnet Technologies
• Original Assignee: Moving Magnet Technologies
• Inventors: Andrieux, Gael, Biwersi, Stephane
• Primary Examiner(s): Leung; Quyen
• Assistant Examiner(s): Gonzalez Quinones; Jose A
• Application Number:
  US11/910,172
• Publication Number:
  US 20080284261A1
• Time in Patent Office: 1,790 Days
• Field of Search: 310 34- 37, 310 28- 30, 310/32, 335/229, 123/90.11
• US Class Current: 310/30
• CPC Class Codes: F01L 9/20 by electric means
• CPC Class Codes: F02D 2041/2079 the circuit having several coils acting on the same anchor
• CPC Class Codes: F02D 41/20 Output circuits, e.g. for controlling currents in command coils
• CPC Class Codes: H01F 2007/1692 Electromagnets or actuators with two coils
• CPC Class Codes: H01F 7/122 by permanent magnets H01F7/1615, H01F7/1646 take precedence
• CPC Class Codes: H01F 7/13 characterised by pulling-force characteristics
• CPC Class Codes: H01F 7/14 Pivoting armatures H01F7/17 takes precedence
• CPC Class Codes: H01F 7/1646 Armatures or stationary parts of magnetic circuit having permanent magnet

Abstract

The invention relates to an electromagnetic actuator comprised of a mobile assembly, a fixed ferromagnetic stator assembly, at least one electric field coil, and of at least one permanent magnet, having two stable positions of equilibrium without current at its ends of travel. The invention is characterized in that the mobile assembly has two distinct ferromagnetic armatures placed on both sides of the stator assembly and each forms, together with the stator assembly, at least one magnetic circuit, and is characterized in that the permanent magnet magnetically cooperates with one of the other ferromagnetic mobile parts in a stable position of equilibrium without current at the end of travel.

Claims

1. An electromagnetic actuator, comprising:

a fixed ferromagnetic statoric assembly including a single electric energizing coil and a permanent magnet;

first and second separate ferromagnetic armatures distributed on either side of the statoric assembly, the first and second armatures having a fixed relative position and being movable between first and second de-energized stable end positions;

the first and second armatures each forming one magnetic circuit with the statoric assembly in the first and second end positions, respectively; and

the permanent magnet magnetically cooperates with the first and second armatures to form a magnetic circuit, respectively, in each of the first and second end positions.

2. An electromagnetic actuator according to claim 1, characterized in that the statoric assembly is composed of a ferromagnetic core surrounded by a thin transversely magnetized magnet, said core being further surrounded by the electric coil coaxial with the permanent magnet, said statoric assembly further including an outer yoke surrounding said permanent magnet and said electric coil, so as to form pole tips capable of magnetically cooperating with either one of the ferromagnetic armatures.

3. An electromagnetic actuator according to claim 1, characterized in that the statoric assembly has a rectangular cross-section.

4. An electromagnetic actuator according to claim 1, characterized in that the statoric assembly has a circular cross-section.

5. An electromagnetic actuator according to claim 2, further comprising an axis going through the statoric assembly and supporting at least one ferromagnetic armature having a cross-section corresponding to the cross-section of the outer yoke.

6. An electromagnetic actuator according to claim 2, further comprising an axis going through the statoric assembly and supporting the first and second ferromagnetic armatures disposed on either side of the statoric assembly.

7. An electromagnetic actuator according to claim 1, characterized in that the first and second armatures move linearly.

8. An electromagnetic actuator according to claim 1, characterized in that the electromagnetic actuator is single-phase.

9. An electromagnetic actuator according to claim 1, further comprising an elastic system exerting a force tending to hold the first and second armatures close to a middle of travel of the first and second armatures.

10. An electromagnetic actuator according to claim 9, characterized in that said elastic system is composed of two compression springs, each exerting a substantially equivalent force on each of the first and second armatures composing mechanical stops for the springs.

11. An electromagnetic actuator according to claim 10, characterized in that springs are placed on a same side of the statoric assembly and separated by an additional mechanical part mounted on an axis of the first and second armatures.

12. An electromagnetic actuator according to claim 1, further comprising two flat magnets disposed substantially symmetrically with respect to a median plane containing a displacement axis of the first and second armatures.

13. An electromagnetic actuator according to claim 1, further comprising a magnetized thin bushing (OZ), having an axis of revolution which is colinear with a main axis of the actuator and which is substantially radially magnetized.

14. An electromagnetic actuator according to claim 1, characterized in that the statoric part is laminated.

15. An electromagnetic actuator according to claim 1, characterized in that either armature comes in direct contact with the statoric assembly in the ends of travel positions.

16. An electromagnetic actuator according to claim 1, further comprising a nonmagnetic part which secures a residual air-gap in the ends of travel of the first and second armatures.

17. An electromagnetic actuator according to claim 1, characterized in that a residual air-gap is maintained at ends of travel positions of the armatures between the armatures and the statoric assembly, by an element of the armatures and an element of a frame which the statoric assembly is integral with.

18. An electromagnetic actuator according to claim 1, characterized in that a current modulation in a phase of the actuator allows a minimization of an impact velocity at an end of travel.

19. An electromagnetic actuator according to claim 1, further comprising at least one sensor detecting a position of the first and second armatures.

20. An electromagnetic actuator according to claim 1, further comprising at least one position sensor embedded in a statoric armature.

21. An electromagnetic actuator according to claim 1, further comprising at least one position sensor integrated in the first or second armature.

22. An electromagnetic actuator according to claim 1, further comprising at least one means for determining a current in at least one of the actuator'"'"'s phases.

23. An electromagnetic actuator according to claim 1, further comprising means for optimizing driving of the actuator by minimizing an impact velocity at an end of travel of the first and second armatures based on current information of a phase of the actuator and/or position information of the first or second armature.

24. An electromagnetic actuator according to claim 1, wherein

the first and second armatures are hinged around a rotating axis and are arranged to contact the statoric part by rotating to one of the first and second end positions to contact a beveled surface of magnetic poles of the statoric part.

25. An electromagnetic actuator according to claim 24, wherein

the rotation axis is located substantially at a center of a median plane between the first and second armatures.

26. An electromagnetic actuator according to claim 24, wherein

a direction of the rotating of the first and second armatures lies in a plane which cross-sects the single coil.

27. An electromagnetic actuator according to claim 1, wherein

the single coil has a long axis which extends in a linear direction which is common to a direction of travel of the first and second armatures between the first and second de-energized stable end positions.