High force and low noise linear fine-tooth motor

Patent metadata

Field	Value
Publication number	US-11296587-B2
Application number	US-201716341759-A
Country	US
Kind code	B2
Filing date	Nov 30, 2017
Priority date	Nov 30, 2016
Publication date	Apr 5, 2022
Grant date	Apr 5, 2022

Abstract

High force and low noise linear fine-tooth motors are described herein. Such motors can include armatures having fine teeth separated by narrow slots such that a ratio of a pitch between teeth and a pitch between permanent magnet poles is less than that of a conventional iron-core linear motor. In one embodiment, such a linear motor can include a first component having an armature including a plurality of iron cores surrounded by coil windings, and a second component having a plurality of permanent magnets with alternating polarity. The plurality of iron cores can be spaced apart from one another by an iron core pitch distance and the plurality of permanent magnets can be spaced apart from one another by a permanent magnet pole pitch distance, and a ratio of the iron core pitch to the magnetic pole pitch can be less than 1.33.

First claim

What is claimed is:

1. A linear motor, comprising:
a first component having an armature including a plurality of core teeth separated by slots and surrounded by coil windings, wherein the coil windings include a plurality of phase windings each wired in series to have alternating polarities, wherein a coil of one or more of the plurality of phase windings overlaps with coils of other ones of the plurality of phase windings, wherein the coil windings include coils wound from a bottom half of a first slot to a top half of a second slot, wherein there are one or more slots located between the first and second slot; and
a second component having a plurality of permanent magnets with alternating polarity;
wherein the first component and the second component are adjacent and configured to translate relative to one another along a movement axis;
wherein the plurality of core teeth are spaced apart from one another by an iron core pitch distance and the plurality of permanent magnets are spaced apart from one another by a permanent magnet pole pitch distance;
wherein a ratio of the iron core pitch distance to the permanent magnet pole pitch distance is less than or equal to 0.2.

2. The linear motor of claim 1 , wherein the first component is stationary and the second component is configured to translate relative to the first component.

3. The linear motor of claim 1 , wherein the second component is stationary and the first component is configured to translate relative to the second component.

4. The linear motor of claim 1 , wherein the first component has a length extending along the movement axis that is greater than a length of the second component extending along the movement axis.

5. The linear motor of claim 1 , wherein the second component has a length extending along the movement axis that is greater than a length of the first component extending along the movement axis.

6. The linear motor of claim 1 , wherein the plurality of permanent magnets are arranged in a Halbach array.

7. The linear motor of claim 1 , wherein a longitudinal axis of each of the plurality of permanent magnets is normal to the movement axis.

8. The linear motor or claim 1 , wherein a longitudinal axis of each of the plurality of permanent magnets is oblique to the movement axis.

9. The linear motor of claim 8 , wherein an angle (α) between the longitudinal axis of each permanent magnet and the movement axis is based on the iron core pitch distance (τ 1 ) and a depth of the armature (D) such that:

α
=

9
⁢
0

-

tan

-
1

⁢

τ
t

D

.

10. The linear motor of claim 8 , wherein an angle between the longitudinal axis of each permanent magnet and the movement axis is between about 80 degrees and about 90 degrees.

11. The linear motor of claim 10 , wherein the angle is about 85.6 degrees.

12. The linear motor of claim 1 , further comprising a power source coupled to the coil windings and configured to selectively energize the coil windings to cause relative movement of the first component and the second component.

13. The linear motor of claim 1 , wherein the coil windings include a plurality of separate phase windings.

14. The linear motor of claim 1 , wherein the coil windings include greater than three phase windings.

15. The linear motor of claim 1 , wherein the coil windings include five phase windings.

16. The linear motor of claim 1 , wherein the plurality of permanent magnets are disposed on a surface of the second component; and
wherein the first component and the second component are arranged such that the surface of the second component having the plurality of permanent magnets faces the armature of the first component.

17. The linear motor of claim 16 , further comprising:
a third component having a second armature including a second plurality of core teeth surrounded by coil windings; and
a second plurality of permanent magnets with alternating polarity disposed on an opposite surface of the second component from the surface having the plurality of permanent magnets;
wherein the second component is disposed between the first component and the third component such that each of the armatures faces one of the plurality of permanent magnets disposed on the second component.

18. The linear motor of claim 16 , further comprising:
a third component having a second plurality of permanent magnets with alternating polarity disposed on a surface thereof;
wherein the first component is disposed between the second component and the third component.

19. A method of reducing acoustic noise and vibration in a linear motor, comprising:
providing a first component having a plurality of core teeth separated by slots and surrounded by coil windings, wherein the coil windings include a plurality of phase windings each wired in series to have alternating polarities, wherein a coil of one or more of the plurality of phase windings overlaps with coils of other ones of the plurality of phase windings, wherein the coil windings include coils wound from a bottom half of a first slot to a top half of a second slot, wherein there are one or more slots located between the first and second slot;
providing a second component adjacent to the first component, the second component having a plurality of permanent magnets with alternating polarity; and
selectively energizing the coil windings to cause relative translation of the first component and the second component along a movement axis;
wherein the plurality of core teeth are spaced apart from one another by an iron core pitch distance and the plurality of permanent magnets are spaced apart from one another by a permanent magnet pole pitch distance;
wherein a ratio of the iron core pitch distance to the permanent magnet pole pitch distance is less than or equal to 0.2.

20. The method of claim 19 , further comprising skewing each of the plurality of permanent magnets such that a longitudinal axis of each permanent magnet is oblique to the movement axis.

21. The method of claim 20 , wherein an angle between the longitudinal axis of each permanent magnet and the movement axis is about 85.6 degrees.

22. The method of claim 19 , further comprising:
providing a second plurality of permanent magnets with alternating polarity on an opposite side of the second component from the plurality of permanent magnets; and
positioning a third component having a second plurality of core teeth surrounded by coil windings such that the second component is disposed between the first component and the third component and each of the armatures faces one of the plurality of permanent magnets of the second component to balance forces normal to the movement axis.

23. The method of claim 19 , further comprising:
providing a third component having a second plu

Assignees

• Massachusetts Inst Technology

Inventors

• Trumper David L
• Yoon Jun Young

Classifications

• H02K41/031 Primary

  of the permanent magnet type · CPC title

• H02K3/28

  Layout of windings or of connections between windings (windings for pole-changing H02K17/06, H02K17/14, H02K19/12, H02K19/32) · CPC title

• H02K2213/03

  Machines characterised by numerical values, ranges, mathematical expressions or similar information · CPC title

• H02K29/03

  with a magnetic circuit specially adapted for avoiding torque ripples or self-starting problems · CPC title

• H02K2201/06

  Magnetic cores, or permanent magnets characterised by their skew · CPC title