Spoked rotor having sectioned, high volume magnets

Patent metadata

Field	Value
Publication number	US-12040662-B2
Application number	US-202117323814-A
Country	US
Kind code	B2
Filing date	May 18, 2021
Priority date	May 18, 2021
Publication date	Jul 16, 2024
Grant date	Jul 16, 2024

Abstract

A rotor assembly for an electric motor includes a rotor core and a plurality of magnets. The rotor core defines a rotation axis. Each of the magnets includes a magnet stem portion and a magnet arm portion. The magnet stem portion extends radially relative to the rotational axis to present a radially outermost stem end. The magnet arm portion is located at least in part radially outward from the stem end. In addition, the magnet arm portion extends circumferentially in opposite directions relative to the magnet stem portion.

First claim

The invention claimed is:

1. A rotor assembly for an electric motor, said rotor assembly comprising:
a rotor core defining a rotational axis and presenting an outer circumferential core surface,
said rotor core including a plurality of axially extending magnet slots, each of which presents a slot stem portion extending radially relative to the rotational axis, a slot arm portion, and a slot aperture extending outward from the slot arm portion,
said slot stem portion and said slot aperture being defined by a pair of radially extending, opposing sidewalls,
each sidewall having a circumferentially extending outer tab located proximate the outer circumferential core surface and spaced from the slot arm portion; and
a plurality of magnets spaced arcuately about said rotor core,
each of said magnets including a magnet stem portion and a magnet arm portion,
said magnet stem portion being received in the slot stem portion and extending radially relative to the rotational axis to present a radially outermost stem end,
said magnet arm portion being received in the slot arm portion and located at least in part radially outward from the stem end and extending circumferentially in opposite directions relative to the magnet stem portion.

2. The rotor assembly in accordance with claim 1 ,
each of said magnet stem and arm portions having a cuboid shape.

3. The rotor assembly in accordance with claim 2 ,
said magnet stem and arm portions being arranged substantially perpendicularly relative to one another.

4. The rotor assembly in accordance with claim 3 ,
said magnet arm portion being entirely located radially outward from the magnet stem portion.

5. The rotor assembly in accordance with claim 4 ,
said magnet stem and arm portions being in contact with one another, such that each magnet is continuous.

6. The rotor assembly in accordance with claim 5 ,
said magnet arm portion being singular, such that each magnet is T-shaped and includes only the singular magnet arm portion located radially outward from the magnet stem portion.

7. The rotor assembly in accordance with claim 6 ,
said magnet arm portion presenting an arm thickness measured in a radial direction,
said magnet stem portion presenting a stem thickness measured in a tangential direction perpendicular to the radial direction,
said arm and stem thicknesses being substantially equal.

8. The rotor assembly in accordance with claim 7 ,
said magnet stem portion defining a longitudinal stem axis that extends radially and is centrally located in the tangential direction,
said magnet arm portion extending equally in opposite directions relative to the longitudinal stem axis.

9. The rotor assembly in accordance with claim 1 ,
said magnet arm portion being spaced from the outer circumferential core surface.

10. The rotor assembly in accordance with claim 9 ,
said rotor core presenting a radially innermost hub that defines a central shaft-receiving opening,
said magnet stem portion being spaced from the hub.

11. The rotor assembly in accordance with claim 1 ,
said aperture being open.

12. The rotor assembly in accordance with claim 1 ,
each of said magnet slots being T-shaped.

13. The rotor assembly in accordance with claim 1 ,
said rotor core comprising a plurality of pole segments circumferentially spaced from one another, with a respective one of the magnet slots being defined between adjacent pole segments,
each pole segment including magnet-locating structure.

14. The rotor assembly in accordance with claim 13 ,
said magnet-locating structure comprising a circumferentially extending radially inner tab,
said radially inner tab extending into the slot stem portion of the corresponding magnet slot.

15. The rotor assembly in accordance with claim 1 ,
said magnet arm portion being entirely located radially outward from the magnet stem portion,
said magnet stem and arm portions being in contact with one another, such that each magnet is continuous.

16. The rotor assembly in accordance with claim 1 ,
said slot arm portion having a circumferentially extending first slot width,
said slot aperture having a circumferentially extending second slot width,
said first slot width being greater than said second slot width.

Assignees

• Nidec Motor Corp

Inventors

• Ley Bruce
• Sullivan Timothy H
• Wolf Scott

Classifications

• H02K2213/03

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

• H02K2201/06

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

• H02K5/04

  Casings or enclosures characterised by the shape, form or construction thereof · CPC title

• H02K1/14

  Stator cores with salient poles · CPC title

• H02K1/2773 Primary

  consisting of tangentially magnetized radial magnets · CPC title