Electric machine having rotor with slanted permanent magnets

Patent metadata

Field	Value
Publication number	US-2016126790-A1
Application number	US-201314899005-A
Country	US
Kind code	A1
Filing date	Jun 20, 2013
Priority date	Jun 20, 2013
Publication date	May 5, 2016
Grant date	—

Abstract

An electric machine including a rotor and an annularly-shaped first stator is provided. The rotor includes an annularly-shaped rotor body and permanent magnets positionally-fixed relative to the rotor body. The first stator includes circumferentially-spaced stator poles. The rotor and the first stator are concentric and axially-aligned relative to an axial centerline of the electric machine. Each of the permanent magnets creates a magnetic dipole. Each magnetic dipole extends along a dipole axis that passes through the respective permanent magnet. Each dipole axis extends in a first plane. The centerline of the electric machine extends in a second plane that is at least substantially perpendicular to the first plane. Each of the permanent magnets is positioned so that a magnet angle that is between 15° and 75° is defined between the respective dipole axis and a radial axis that extends between the respective permanent magnet and the centerline.

First claim

What is claimed is:

1 . An electric machine, comprising:
a rotor that includes an annularly-shaped rotor body and a plurality of permanent magnets positionally-fixed relative to the rotor body; an annularly-shaped first stator that includes a plurality of circumferentially-spaced stator poles; wherein the rotor and the first stator are concentric and axially-aligned relative to an axial centerline of the electric machine; wherein each of the plurality of permanent magnets creates a magnetic dipole, wherein each magnetic dipole extends along a dipole axis that passes through the respective permanent magnet, wherein each dipole axis extends in a first plane, and wherein the centerline of the electric machine extends in a second plane that is at least substantially perpendicular to the first plane; wherein each of the plurality of permanent magnets is positioned so that a magnet angle that is between 15° and 75° is defined between the respective dipole axis and a radial axis that extends between the respective permanent magnet and the centerline of the electric machine.

2 . The electric machine of claim 1 , wherein the rotor body includes a plurality of axially-extending slots within which the plurality of permanent magnets are disposed.

3 . The electric machine of claim 1 , wherein the magnet angles of the plurality of permanent magnets are all the same.

4 . The electric machine of claim 1 , wherein the magnet angles of the plurality of permanent magnets are not all the same.

5 . The electric machine of claim 1 , wherein the rotor includes a plurality of magnet groups, wherein each of the plurality of magnet groups includes at least two of the plurality of permanent magnets, wherein the magnet angles of the plurality of permanent magnets within each of the plurality of magnet groups are form a pattern that is repeated within each of plurality of magnet groups.

6 . The electric machine of claim 1 , wherein the plurality of permanent magnets are positioned so that the magnetic dipole of each of the plurality of permanent magnets has a polarity that is opposite the magnetic dipole of an adjacent permanent magnet.

7 . The electric machine of claim 1 , wherein the plurality of permanent magnets are positioned so that they are circumferentially overlapping.

8 . The electric machine of claim 7 , wherein a radially outer end of each of the plurality of permanent magnets circumferentially overlaps a radially inner end of an adjacent permanent magnet.

9 . The electric machine of claim 1 , wherein the plurality of permanent magnets are positioned so that they are circumferentially non-overlapping.

10 . The electric machine of claim 1 , wherein each of the plurality of permanent magnets has an outer exposure fraction that is equal to a ratio of a body width of the respective permanent magnet and an inner exposure width of the respective permanent magnet, wherein the outer exposure fraction is greater than one.

11 . The electric machine of claim 1 , wherein each of the plurality of permanent magnets has an inner exposure fraction that is equal to a ratio of a body width of the respective peimanent magnet and an inner exposure width of the respective permanent magnet, wherein the inner exposure fraction is greater than one.

12 . The electric machine of claim 1 , wherein the rotor includes a plurality of flux barriers, wherein each of the plurality of flux barriers is disposed circumferentially between one of the plurality of permanent magnets and an adjacent permanent magnet.

13 . The electric machine of claim 12 , wherein each of the plurality of flux barriers is an axially-extending aperture disposed in the rotor.

14 . The electric machine of claim 1 , wherein each of the plurality of stator poles of the first stator is formed by a stator tooth that extends radially from the first stator, and a stator coil that is wound around the stator tooth.

15 . The electric machine of claim 1 , further comprising an annularly-shaped second stator that includes a plurality of circumferentially-spaced stator poles.

16 . The electric machine of claim 15 , wherein each of the plurality of stator poles of the second stator is formed by a stator tooth that extends radially from the second stator, and a stator coil that is wound around the stator tooth.

17 . The electric machine of claim 15 , wherein the rotor, the first stator, and the second stator are concentric and axially-aligned relative to the centerline of the electric machine, and wherein the rotor is positioned concentrically between the first stator and the second stator.

18 . The electric machine of claim 15 , wherein each of the plurality of stator poles on the first stator corresponds to one of the plurality of stator poles on the second stator, and wherein the corresponding stator poles on the first and second stators are offset from one another by an offset angle.

19 . A rotor for use in an electric machine, comprising:
an annularly-shaped rotor body and a plurality of permanent magnets positionally-fixed relative to the rotor body; wherein the rotor body is concentric relative to an axially-extending centerline of the electric machine; wherein the rotor body includes a plurality of axially-positioned rotor rings, each including a plurality of arcuate rotor body pieces that are positioned end-to-end to form the respective rotor rings; wherein each of the plurality of permanent magnets creates a magnetic dipole, wherein each magnetic dipole extends along a dipole axis that passes through the respective permanent magnet, wherein each dipole axis extends in a first plane, and wherein the centerline of the electric machine extends in a second plane that is at least substantially perpendicular to the first plane; wherein each of the plurality of permanent magnets is positioned so that a magnet angle that is between 15° and 75° is defined between the respective dipole axis and a radial axis that extends between the respective permanent magnet and the centerline of the electric machine.

20 . A rotor for use in an electric machine, comprising:
an annularly-shaped rotor body and a plurality of permanent magnets positionally-fixed relative to the rotor body; wherein the rotor body is concentric relative to an axially-extending centerline of the electric machine; wherein the rotor body includes a plurality of arcuate rotor body pieces that are positioned end-to-end to form the rotor body; wherein each of the arcuate rotor body pieces includes a plurality of axially-positioned panels that are axially-compressed to form the respective rotor body piece; wherein each of the plurality of permanent magnets creates a magnetic dipole, wherein each magnetic dipole extends along a dipole axis that passes through the respective permanent magnet, wherein each dipole axis extends in a first plane, and wherein the centerline of the electric machine extends in a second plane that is at least substantially perpendicular to the first plane; wherein each of the plurality of permanent magnets is positioned so that a magnet angle that is between 15° and 75° is defined between the respective dipole axis and a radial axis that extends between the respective permanent magnet and the centerline of the electric machine.

Assignees

• Otis Elevator Co

Inventors

• Piech Zbigniew
• Tangudu Jagadeesh
• Himmelmann Richard A

Classifications

• H02K1/27 Primary

  Rotor cores with permanent magnets · CPC title

• H02K1/2766

  having a flux concentration effect · CPC title

• H02K16/04

  Machines with one rotor and two stators · CPC title

• H02K1/30

  using intermediate parts, e.g. spiders · CPC title

• H02K1/276

  Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM] · CPC title