Linear motor with electromagnetically actuated spring mover

Patent metadata

Field	Value
Publication number	US-9685847-B2
Application number	US-201414169506-A
Country	US
Kind code	B2
Filing date	Jan 31, 2014
Priority date	Jan 31, 2014
Publication date	Jun 20, 2017
Grant date	Jun 20, 2017

Abstract

Reluctance-based resonant linear motors and methods of operation are provided. An example linear motor includes a spring having a plurality of coils. The linear motor includes a stator coaxially surrounding at least a portion of the spring. The stator includes a plurality of teeth. The linear motor includes a plurality of windings respectively positioned within a plurality of winding cavities respectively formed by the plurality of teeth. The application of electrical energy to the plurality of windings generates a magnetic field that flows through one or more of the coils of the spring. The flow of the magnetic field through the one or more coils of the spring causes the spring to actuate towards a compressed position. An example method includes periodically applying electrical energy to the plurality of windings such that the spring oscillates at a resonance frequency associated with the linear motor.

First claim

What is claimed is:

1. A linear motor comprising:
a spring having a plurality of coils;
a stator coaxially surrounding at least a portion of the spring, wherein the stator comprises a plurality of teeth; and
a plurality of windings respectively positioned within a plurality of winding cavities respectively formed by the plurality of teeth, an uncompressed pitch of the spring being greater than a winding interval between each of the plurality of windings;
wherein application of electrical energy to the plurality of windings generates a magnetic field that flows through one or more of the coils of the spring; and
wherein the flow of the magnetic field through the one or more coils of the spring causes the spring to actuate towards a compressed position.

2. The linear motor of claim 1 , wherein:
application of the electrical energy to the plurality of windings respectively generates a plurality of flux loops;
the spring is positioned within the stator such that a substantial portion of each of the plurality of flux loops flows through one or more of the coils of the spring; and
the flow of each of the plurality of flux loops through the respective one or more of the coils of the spring causes the spring to actuate towards the compressed position.

3. The linear motor of claim 1 , wherein:
the spring provides a first amount of reluctance to the magnetic field when the spring is in an uncompressed position;
the spring provides a second amount of reluctance to the magnetic field when the spring is in the compressed position; and
the first amount is greater than the second amount, such that the flow of the magnetic field through the one or more coils of the spring results in magnetic forces that cause the spring to actuate towards the compressed position, thereby minimizing system reluctance.

4. The linear motor of claim 1 , wherein a first end of the spring is secured in place with respect to a first end of the stator.

5. The linear motor of claim 4 , wherein the first end of the spring is aligned with the winding cavity most proximate to the first end of the stator.

6. The linear motor of claim 1 , wherein the plurality of teeth comprise a plurality of annular teeth spaced at intervals along a longitudinal axis of the stator and extending inwards towards the spring.

7. The linear motor of claim 1 , wherein the plurality of windings have alternating winding directions.

8. The linear motor of claim 1 , wherein:
application of the electrical energy to the plurality of windings respectively generates a plurality of flux loops; and
each of the plurality of flux loops flows through two of the plurality of teeth.

9. The linear motor of claim 1 , further comprising a piston driven by the spring.

10. The linear motor of claim 9 , further comprising a cylinder having a chamber into which the piston is driven to compress a gas.

11. The linear motor of claim 1 , wherein the plurality of coils respectively have a generally rectangular cross-sectional area.

12. A linear motor comprising:
a spring having a plurality of coils, wherein a plurality of air gaps respectively exist between the plurality of coils when the spring is in an uncompressed position;
a generally cylindrical stator surrounding at least a portion of the spring; and
a plurality of windings respectively positioned within a plurality of winding cavities spaced along a longitudinal axis of the stator, wherein a pitch of the spring is greater than a winding interval between each of the plurality of windings;
wherein application of electrical energy to the plurality of windings generates a magnetic field that flows through one or more of the plurality of coils; and
wherein the flow of the magnetic field through the one or more of the plurality of coils actuates the spring towards a compressed position in which the plurality of air gaps are reduced, thereby reducing the reluctance experienced by the magnetic field.

13. The linear motor of claim 12 , wherein:
application of electrical energy to the plurality of windings respectively generates a plurality of flux loops having alternating rotational directions;
the spring is positioned within the stator such that a substantial portion of each of the plurality of flux loops flows through one or more of the coils of the spring; and
the flow of each of the plurality of flux loops through the respective one or more coils of the spring actuates the spring towards the compressed position in which the plurality of air gaps are reduced, thereby reducing the reluctance experienced by each of the plurality of flux loops.

14. The linear motor of claim 13 , wherein:
the plurality of winding cavities are respectively formed by a plurality of pairs of teeth extending from the stator inwards towards the spring; and
the flux loop generated by each winding flows through the stator and the pair of teeth forming the winding cavity.

15. A method of operating a linear motor, the method comprising:
providing the linear motor, wherein the linear motor comprises:
a spring having a plurality of coils;
a stator coaxially surrounding at least a portion of the spring, wherein the stator comprises a plurality of teeth; and
a plurality of windings respectively positioned within a plurality of winding cavities respectively formed by the plurality of teeth; and
applying electrical energy to the plurality of windings to generate a magnetic field that flows through one or more of the coils of the spring, wherein applying electrical energy to the plurality of windings to generate the magnetic field comprises applying to the plurality of windings a sinusoidal voltage waveform having a frequency that is equal to one-half a resonant frequency associated with the linear motor;
wherein the flow of the magnetic field through the one or more coils of the spring causes the spring to actuate towards a compressed position.

16. The method of claim 15 , wherein applying electrical energy to the plurality of windings to generate the magnetic field comprises applying to the plurality of windings a square voltage waveform having a frequency that is equal to a resonant frequency associated with the linear motor.

Assignees

• Gen Electric
• Haier Us Appliance Solutions Inc

Inventors

• Filippa Mariano Pablo

Classifications

• F04B17/03

  driven by electric motors · CPC title

• H02K41/02

  Linear motors; Sectional motors · CPC title

• H02K41/00

  Propulsion systems in which a rigid body is moved along a path due to dynamo-electric interaction between the body and a magnetic field travelling along the path {(electromagnetic launchers F41B6/00)} · 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

• H02K33/04

  wherein the frequency of operation is determined by the frequency of uninterrupted AC energisation · CPC title