Electromagnetic actuators and component designs therefor

Patent metadata

Field	Value
Publication number	US-9787169-B2
Application number	US-201414217095-A
Country	US
Kind code	B2
Filing date	Mar 17, 2014
Priority date	Mar 15, 2013
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

Abstract

An embodiment of an electromagnetic actuator, such as a moving magnet actuator (MMA), includes a back iron, a first coil winding, a second coil winding, a mover, and a permanent magnet. The first and second coil windings are connected to the back iron, and have generally annular shapes. The mover moves relative to the back iron during use of the MMA. The permanent magnet is connected to the mover and moves with the mover during use of the MMA. The permanent magnet has a generally annular shape.

First claim

The invention claimed is:

1. An electromagnetic actuator, comprising:
a first coil winding having a generally annular shape;
a second coil winding having a generally annular shape, said second coil winding located radially inside of said first coil winding;
a permanent magnet having a generally annular shape and located radially between said first coil winding and said second coil winding, said permanent magnet moving relative to said first and second coil windings and moving solely within an axial extent provided between axial ends of said first and second coil windings during use of the electromagnetic actuator;
a mover connected to said permanent magnet and moving with said permanent magnet relative to said first and second coil windings during use of the electromagnetic actuator; and
a stationary back iron having a closed axial end and having an open axial end through which said mover extends, wherein said closed axial end serves as a magnetic flux path and said open axial end lacks a magnetic flux path via said back iron, and wherein, during use of the electromagnetic actuator, emitted magnetic flux passes through said closed axial end.

2. An electromagnetic actuator as set forth in claim 1 , wherein said back iron has an outer portion that is generally cylindrical and has an inner portion that is generally cylindrical and is located radially-inwardly of said outer portion, said first coil winding is connected to said outer portion and said second coil winding is connected to said inner portion.

3. An electromagnetic actuator as set forth in claim 1 , further comprising:
a third coil winding having a generally annular shape and located axially away from said first coil winding;
a fourth coil winding having a generally annular shape, said fourth coil winding located radially inside of said third coil winding, said fourth coil winding located axially away from said second coil winding;
a second permanent magnet having a generally annular shape and located radially between said third coil winding and said fourth coil winding, said second permanent magnet moving relative to said third and fourth coil windings during use of the electromagnetic actuator; and
said mover connected to said second permanent magnet, said mover moving with said first and second permanent magnets during use of the electromagnetic actuator.

4. An electromagnetic actuator as set forth in claim 3 , said back iron having an outer portion that is generally cylindrical and having an inner portion that is generally cylindrical and is located radially-inwardly of said outer portion, said first coil winding and said third coil winding connected to said outer portion, said second coil winding and said fourth coil winding connected to said inner portion.

5. An electromagnetic actuator as set forth in claim 1 , further comprising:
said back iron connected to said first coil winding and connected to said coil winding;
a third coil winding indirectly connected to said back iron, said third coil winding having a generally annular shape and located radially between said first coil winding and said second coil winding; and
a second permanent magnet connected to said mover and moving with said mover during use of the electromagnetic actuator, said second permanent magnet having a generally annular shape and located radially between said second coil winding and said third coil winding, said first permanent magnet located radially between said first coil winding and said third coil winding.

6. An electromagnetic actuator as set forth in claim 1 , further comprising:
said back iron connected to said first coil winding and connected to said second coil winding;
a third coil winding connected to said back iron, said third coil winding having a generally annular shape and located radially between said first coil winding and said second coil winding;
a fourth coil winding connected to said back iron, said fourth coil winding having a generally annular shape and located radially between said first coil winding and said third coil winding; and
a second permanent magnet connected to said mover and moving with said mover during use of the electromagnetic actuator, said second permanent magnet having a generally annular shape and located radially between said second coil winding and said third coil winding, said first permanent magnet located radially between said first coil winding and said fourth coil winding.

7. An electromagnetic actuator as set forth in claim 1 , wherein said first coil winding, said second coil winding, or both, has an axial end with a greater number of individual coil windings than the number of individual coil windings away from said axial end.

8. An electromagnetic actuator as set forth in claim 1 , wherein said first coil winding and said second coil winding are concentric with respect to each other, said permanent magnet is concentric with respect to said first coil winding and said second coil winding, and said first coil winding and said second coil winding generally confront each other across a spacing, and said permanent magnet is located within said spacing radially between said first coil winding and said second coil winding and moves in said spacing during use of the electromagnetic actuator.

9. An electromagnetic actuator as set forth in claim 1 , wherein said permanent magnet is magnetized in a radial direction relative to the generally annular shape of said permanent magnet.

10. An electromagnetic actuator as set forth in claim 1 , wherein said back iron has a hollow interior defined at least in part by an inside surface of said outer portion, by an outside surface of said inner portion, and by a back wall of said closed axial end.

11. An electromagnetic actuator comprising:
a first coil winding having a generally annular shape;
a second coil winding having a generally annular shape, said second coil winding located radially inside of said first coil winding;
a permanent magnet having a generally annular shape and located radially between said first coil winding and said second coil winding, said permanent magnet moving relative to said first and second coil windings during use of the electromagnetic actuator;
a third coil winding having a generally annular shape and located axially away from said first coil winding;
a fourth coil winding having a generally annular shape, said fourth coil winding located radially inside of said third coil winding, said fourth coil winding located axially away from said second coil winding;
a second permanent magnet having a generally annular shape and located radially between said third coil winding and said fourth coil winding, said second permanent magnet moving relative to said third and fourth coil windings during use of the electromagnetic actuator;
a mover connected to said first permanent magnet and connected to said second permanent magnet, said mover moving with said first and second permanent magnets during use of the electromagnetic actuator; and
a stationary back iron, said back iron having an outer portion that is generally cylindrical and having an inner portion that is generally cylindrical and is located radially-inwardly of said outer portion, said first coil winding and said third coil winding connected to said outer portion, said second coil winding and said fourth coil winding connected to said inner portion, wherein said back iron has a first open axial end and has a second open axial end opposite said first open axial end.

12. A moving magnet actuator, comprising:
a first coil winding having a generally annular shape;
a second coil winding having a generally annular shape, said second coil winding located radially in

Assignees

• Univ Michigan Regents

Inventors

• Hiemstra David
• Parmar Gaurav
• Welch Cory
• Awtar Shorya

Classifications

• H02K33/12

  with armatures moving in alternate directions by alternate energisation of two coil systems · CPC title

• H02K41/0356 Primary

  moving along a straight path · CPC title

• H02K33/00

  Motors with reciprocating, oscillating or vibrating magnet, armature or coil system (arrangements for handling mechanical energy structurally associated with motors H02K7/00, e.g. H02K7/06) · CPC title