Electric machine with combined axial- and radial-flux

Patent metadata

Field	Value
Publication number	US-11482894-B2
Application number	US-202017071386-A
Country	US
Kind code	B2
Filing date	Oct 15, 2020
Priority date	Oct 15, 2020
Publication date	Oct 25, 2022
Grant date	Oct 25, 2022

Abstract

An axial-flux and radial-flux motor including a rotor mounted rotatably about a machine axis, with the rotor rotatively attached to a shaft. A stator assembly having a core with a non-ferromagnetic material and including a first axial-flux stator yoke with an inner wall rigidly attached on an outer surface of a first edge wall of the core. A second axial-flux stator yoke having an inner wall rigidly attached on an outer surface of a second edge wall of the core. The first and the second axial-flux stator yokes each include an outer wall with slots. A radial-flux stator yoke with slots includes an inner wall rigidly attached on a continuous outer wall of the core. The radial-flux stator yoke and the first and the second axial-flux stator yokes include laminated sheets. Windings positioned in the slots of the first and the second axial-flux stator yokes and the radial-flux stator yoke.

First claim

What is claimed is:

1. An electrical machine that is an axial-flux and radial-flux motor, comprising:
a rotor mounted rotatably about a machine axis, with the rotor rotatively attached to a shaft; and
a stator assembly having a stator core with a non-ferromagnetic material and including
a first axial-flux stator yoke having an inner wall rigidly attached on an outer surface of a first edge wall of the stator core, and a second axial-flux stator yoke having an inner wall rigidly attached on an outer surface of a second edge wall of the stator core, wherein the first and the second axial-flux stator yokes each include an outer wall with slots;
a radial-flux stator yoke with slots includes a continuous inner wall rigidly attached on a continuous outer wall of the stator core, wherein the radial-flux stator yoke and the first and the second axial-flux stator yokes include laminated sheets; and
windings positioned in the slots of the first and the second axial-flux stator yokes and the radial-flux stator yoke.

2. The electric machine of claim 1 , wherein the stator assembly is rigidly attached to the shaft, and wherein the first and the second axial-flux stator yokes have slots in an axial direction, the radial-flux stator yoke has slots located on an outer diameter surface of the continuous outer wall of the stator core, and the windings include a set of toroid-shaped multiphase windings configured within the slots of the first and second axial-flux stator yokes and the radial-flux stator yoke.

3. The electrical machine of claim 1 , further comprising:
a two axial-flux rotor assembly rotatively attached to the shaft via bearings, and engages with the first and the second axial-flux stator yokes, each axial-flux rotor assembly having an axial-flux rotor housing rigidly attached to an outer race of bearings, an axial-flux rotor back-iron attached to the axial-flux rotor housing, and an axial-flux permanent magnet array attached to the axial-flux rotor back-iron.

4. The electrical machine of claim 3 , further comprising:
a radial-flux rotor assembly rigidly connected to an axial-flux rotor housing, and rotatively engaged with the radial-flux stator yoke,
wherein the radial-flux rotor assembly includes a radial-flux rotor housing rigidly attached to the axial-flux rotor housing, a radial-flux rotor back-iron attached to the radial-flux rotor housing, and a radial-flux permanent magnet array attached to the axial-flux rotor back-iron.

5. The electrical machine of claim 4 , wherein the axial-flux permanent magnet arrays of the two axial-flux rotor assembly and the radial-flux permanent magnet array each have alternative polarity.

6. The electrical machine of claim 4 , wherein the first and second axial-flux stator yokes and the axial-flux rotor back-irons of the two axial-flux rotor assembly are made of spiral-shaped electrical lamination, or that the radial-flux stator yoke and radial-flux rotor back-iron are made of stacked electrical lamination.

7. The electrical machine to claim 1 , wherein the non-ferromagnetic material of the stator core includes at least 90% of one or more non-ferromagnetic materials.

8. The electrical machine of claim 1 , wherein the non-ferromagnetic material of the stator core is a material that is one of plastic, carbon fiber reinforced polymer, fiberglass or an iron (ferrous) free material.

9. The electrical machine of claim 1 , wherein the non-ferromagnetic material of the stator core includes a level of an electrically conductive material and a level of mechanical stiffness associated with one of titanium, fiber glass or acetal homopolymer.

10. The electrical machine of claim 1 , wherein the non-ferromagnetic material of the stator core is a material that is one or more non-ferromagnetic metals obtained from sulfide, carbonate or silicate minerals, and is non-magnetic.

11. The electrical machine of claim 1 , wherein the windings are wrapped around the assembled stator yoke and include a winding pattern having end turns which are termed toroidal windings, such that the toroidal windings reduces an amount of a length of the end turns, resulting in an increase in an amount of overall efficiency of the electrical machine, when compared with a similarly configured electric machine without the toroidal windings.

12. The electrical machine to claim 1 , wherein the windings include a copper material and are wrapped around the assembled stator yoke that include a winding pattern with end turns that are termed toroidal windings, such that the toroidal windings reduces an amount of a length of the end turns, resulting in a total amount of a motor's windings copper loss which improves a motor's overall efficiency.

13. The electrical machine of claim 1 , wherein the windings are thermally connected to the shaft, such that the thermal connection of the windings and the shaft is implemented using a thermally conductive and electrically insulating material of epoxy.

14. The electrical machine of claim 1 , further comprising:
bearings are utilized so the rotor is rotatively attached to the shaft, such that the shaft is a hollow stationary shaft, and
wherein the stator core and the shaft include a coupling feature adapted to selectively couple and mate the stator core to the shaft, so that the stator assembly is fixed to the shaft in order to transmit a torque action and maintain an angular correspondence, to produce a torque force.

15. An electrical machine that is an axial-flux and radial-flux motor, comprising:
a rotor mounted rotatably about a machine axis, with the rotor rotatively attached to a stationary shaft; and
a stator assembly including
a stator core with a non-ferromagnetic material, the stator core including a first edge wall, a second edge wall and a continuous outer wall circumferentially positioned around the stator core;
a first axial-flux stator yoke having an inner wall rigidly attached on an outer surface of a first edge wall of the stator core, and a second axial-flux stator yoke having an inner wall rigidly attached on an outer surface of a second edge wall of the stator core, wherein the first and the second axial-flux stator yokes each include an outer wall with slots;
a radial-flux stator yoke with slots includes a continuous inner wall rigidly attached on a continuous outer wall of the stator core, wherein the radial-flux stator yoke and the first and the second axial-flux stator yokes include laminated sheets; and
windings positioned in the slots of the first and the second axial-flux stator yokes and the radial-flux stator yoke, wherein the stator assembly is fixed to the stationary shaft of which the rotor rotates around the same stationary shaft, in order to transmit a torque action to produce a torque force.

16. The electrical machine of claim 15 , wherein the radial-flux stator yoke includes stacked laminations of sheets that are electrically laminated and insulated from each other, such that sheets have substantially a same shape, and are stacked one on top of another in an axial direction or connected to one another.

17. The electrical machine of claim 15 , wherein the first and second axial-flux stator yokes includes stacked laminations of sheets that are electrically laminated and insulated from each other, the stacked laminations of sheets are axisymmetric relative to a radial straight line, wherein the laminations for the first and second axial-flux stator yokes include the sheets stacked one on top of another in a radial direction or connected to one another.

18. The electrical machine of claim 15 , wher

Assignees

• Mitsubishi Electric Res Laboratories Inc

Inventors

• Zhou Lei
• Wang Bingnan
• Wang Hongyu

Classifications

• H02K16/00 Primary

  Machines with more than one rotor or stator {(machines for transmitting mechanical power from a driving shaft to a driven shaft and comprising structurally interrelated motor and generator parts H02K51/00; permanent magnet machines with multiple rotors or stators relatively rotated for vectorially combining the excitation fields or the armature voltages H02K21/029)} · CPC title

• H02K1/16 Primary

  Stator cores with slots for windings · CPC title

• H02K16/04

  Machines with one rotor and two stators · CPC title

• H02K1/148

  Sectional cores (H02K1/141 takes precedence) · CPC title

• H02K1/182

  to stators axially facing the rotor, i.e. with axial or conical air gap · CPC title