US-20260128625-A1 - IN-WHEEL ELECTRIC MACHINES FOR ELECTRIC VEHICLES

Abstract

In-wheel electric machines (e.g., electric motors, electric generators, etc.) for electric vehicles are disclosed. An example in-wheel electric machine includes a stator and a rotor. The stator includes a ferromagnetic core, a plurality of teeth circumferentially arranged about the ferromagnetic core, and a plurality of edgewise coils coupled to the plurality of teeth. Respective ones of the plurality of teeth extend in a radially outward direction from the ferromagnetic core and are spaced apart from one another by respective ones of a plurality of slots. Respective ones of the plurality of edgewise coils are radially loaded onto the respective ones of the plurality of teeth. The rotor is located externally relative to the stator and is configured to rotate relative to the stator. The rotor includes a plurality of permanent magnets arranged in a Halbach array.

Inventors

• Ville PIIPPO
• Tuomo LEHTIMÄKI
• Gareth Roberts
• Joshua Best
• Oliver Holt

Assignees

• DONUT LAB DEVELOPMENT OÜ

Dates

Publication Date

20260507

Application Date

20241107

Claims (20)

1. 1 . An in-wheel electric machine, comprising: a stator including: a ferromagnetic core; a plurality of teeth circumferentially arranged about the ferromagnetic core, respective ones of the teeth extending in a radially outward direction from the ferromagnetic core and being spaced apart from one another by respective ones of a plurality of slots; and a plurality of edgewise coils coupled to the plurality of teeth, respective ones of the edgewise coils being radially loaded onto the respective ones of the teeth; and a rotor located externally relative to the stator, the rotor including a plurality of permanent magnets arranged in a Halbach array, the rotor configured to rotate relative to the stator.
2. 2 . The in-wheel electric machine of claim 1 , wherein each tooth from among the plurality of teeth includes a pair of parallel walls extending in an axial direction of the stator.
3. 3 . The in-wheel electric machine of claim 2 , wherein the parallel walls form a pair of opposed, axially-extending, parallel surfaces configured to enable one of the plurality of edgewise coils to be radially loaded onto one of the plurality of teeth.
4. 4 . The in-wheel electric machine of claim 1 , wherein the stator includes a total of fifty-four teeth and a total of fifty-four slots.
5. 5 . The in-wheel electric machine of claim 4 , wherein the rotor includes a total of fifty-two poles provided by the plurality of permanent magnets, wherein the in-wheel electric machine accordingly has a slot pole combination of fifty-four slots and fifty-two poles.
6. 6 . The in-wheel electric machine of claim 1 , wherein the respective ones of the edgewise coils are coupled to one another.
7. 7 . The in-wheel electric machine of claim 6 , wherein connections between the respective ones of the edgewise coils are formed via respective ones of a plurality of interconnect members, wherein each one of the interconnect members extends between two of the respective ones of the edgewise coils, wherein each one of the interconnect members includes a first end configured to be coupled to a connection point of a first one of the edgewise coils and a second end configured to be coupled to a connection point of a second one of the edgewise coils located adjacent the first one of the edgewise coils.
8. 8 . The in-wheel electric machine of claim 6 , wherein connections between the respective ones of the edgewise coils are formed via respective ones of a plurality of extension arms integrally formed in a first subset of the respective ones of the edgewise coils, wherein a second subset of the respective ones of the edgewise coils do not include the plurality of extension arms, wherein each one of the edgewise coils from among the first subset of the respective ones of the edgewise coils includes a first extension arm configured to be coupled to a connection point of a first one of the edgewise coils from among the second subset of the respective ones of the edgewise coils and a second extension arm configured to be coupled to a connection point of a second one of the edgewise coils from among the second subset of the respective ones of the edgewise coils, wherein the one of the edgewise coils from among the first subset of the respective ones of the edgewise coils is located between the first one and the second one of the edgewise coils from among the second subset of the respective ones of the edgewise coils.
9. 9 . The in-wheel electric machine of claim 6 , wherein connections between the respective ones of the edgewise coils are formed subsequent to the respective ones of the edgewise coils being radially loaded onto the respective ones of the teeth.
10. 10 . The in-wheel electric machine of claim 6 , wherein connections between the respective ones of the edgewise coils are formed prior to the respective ones of the edgewise coils being radially loaded onto the respective ones of the teeth.
11. 11 . The in-wheel electric machine of claim 10 , wherein the connections between the respective ones of the edgewise coils result in formation of a chain including the respective ones of the edgewise coils, wherein the chain is configured to be radially loaded onto the respective ones of the teeth subsequent to formation of the chain.
12. 12 . The in-wheel electric machine of claim 1 , wherein the respective ones of the edgewise coils are arranged as a chain formed by a continuous wire, wherein the chain is configured to be radially loaded onto the respective ones of the teeth subsequent to formation of the chain.
13. 13 . The in-wheel electric machine of claim 1 , further comprising a tire coupled to and located externally relative to the rotor.
14. 14 . A method for assembling an in-wheel electric machine, the method comprising: radially loading respective ones of a plurality of edgewise coils onto respective ones of a plurality of teeth of a stator of the in-wheel electric machine, the stator including a ferromagnetic core, the respective ones of the teeth circumferentially arranged about the ferromagnetic core, the respective ones of the teeth extending in a radially outward direction from the ferromagnetic core and being spaced apart from one another by respective ones of a plurality of slots; and locating a rotor of the in-wheel electric machine externally relative to the stator, the rotor including a plurality of permanent magnets arranged in a Halbach array, the rotor configured to rotate relative to the stator.
15. 15 . The method of claim 14 , wherein each tooth from among the plurality of teeth includes a pair of parallel walls extending in an axial direction of the stator, the parallel walls forming a pair of opposed, axially-extending, parallel surfaces configured to enable one of the plurality of edgewise coils to be radially loaded onto one of the plurality of teeth.
16. 16 . The method of claim 14 , further comprising coupling the respective ones of the edgewise coils to one another.
17. 17 . The method of claim 16 , wherein connections between the respective ones of the edgewise coils are formed subsequent to the respective ones of the edgewise coils being radially loaded onto the respective ones of the teeth.
18. 18 . The method of claim 16 , wherein connections between the respective ones of the edgewise coils are formed prior to the respective ones of the edgewise coils being radially loaded onto the respective ones of the teeth.
19. 19 . The method of claim 18 , wherein the connections between the respective ones of the edgewise coils result in formation of a chain including the respective ones of the edgewise coils, wherein the chain is configured to be radially loaded onto the respective ones of the teeth subsequent to formation of the chain.
20. 20 . The method of claim 14 , wherein the respective ones of the edgewise coils are arranged as a chain formed by a continuous wire, wherein the chain is configured to be radially loaded onto the respective ones of the teeth subsequent to formation of the chain.

Description

FIELD OF THE DISCLOSURE This disclosure relates generally to electric machines (e.g., electric motors, electric generators, etc.) and, more specifically, to in-wheel electric machines for electric vehicles. BACKGROUND Electric motors typically include a stator, a rotor, wound wire (often referred to as “windings”), and field magnets. The stator and the rotor are mechanical components. The rotor is configured to rotate relative to the stator. The stator and the rotor can be implemented in either an internal rotor configuration in which the stator circumscribes the rotor, or conversely in an external rotor configuration in which the rotor circumscribes the stator. The windings and the field magnets are electrical components. One of these components is connected to the stator, while the other is connected to the rotor. A ferromagnetic core of the stator and the windings and the field magnets form a magnetic circuit in which the field magnets generate a magnetic field that interacts with the windings. In response to electrical current supplied to the windings, the magnetic field associated with the field magnets generates torque on the rotor, which in turn causes the rotor to rotate relative to the stator. Electric motors accordingly transform electrical energy into mechanical energy. An electric generator can be constructed in a manner similar to that of the electric motor described above, but with the electric generator instead being configured to transform mechanical energy into electrical energy. An electric machine can be implemented to function and/or operate as both an electric motor and an electric generator. Electric motors exist in many forms and varieties, and can generally be classified based on factors such as the type of power supply, the intended application, the configuration, and the output type. For example, electric motors can be powered by either direct current (DC) sources (e.g., batteries or rectifiers) or alternating current (AC) sources (e.g., power grids, generators, or inverters), can be either brushless or brushed, can be either synchronous or asynchronous, can be configured for either radial flux or axial flux, can include either permanent magnets or electromagnets, and can operate on polyphase, three-phase, two-phase, or single-phase power. Electric motors are widely used across multiple industries (e.g., automotive, medical, household, etc.) and a variety of applications including vehicles, appliances, tools, fans, blowers, turbines, compressors, pumps, etc. Electric vehicles have risen in popularity over the past decade. Electric vehicles are typically powered by one or more electric motor(s) that draw(s) electricity from an onboard rechargeable battery. Electric vehicles exist in many forms; wheeled electric vehicles, for example, include cars, vans, trucks, motorcycles, scooters, etc. that include at least one wheel powered by an electric motor. The majority of wheeled electric vehicles include powertrains having an inboard electric motor, transmission, and driveline, all of which contribute to the mass, complexity, and losses of the propulsion system, as well as a volume penalty within the chassis of the vehicle. In some implementations of a wheeled electric vehicle, the primary components of the electric motor are integrated into and/or incorporated within the wheel itself. Such implementations are commonly referred to as “in-wheel” electric motors. A key advantage of in-wheel electric motors is the ability to eliminate many if not all of the aforementioned peripheral components and the penalties associated therewith, and also to provide significant improvement in transient performance. An in-wheel electric motor is one form of a direct drive electric machine. The integration of electric motors into other forms of direct drive electric machines (e.g., appliances, medical devices, etc.) that do not necessarily include a wheel has also recently risen in popularity. The teachings set forth in the instant disclosure are applicable to direct drive electric machines of all types, including without limitation to in-wheel electric machines (e.g., in-wheel electric motors) for electric vehicles. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of an example electric machine having an internal rotor configuration. FIG. 2 is a side view of an example electric machine having an external rotor configuration. FIG. 3 is a block diagram of an example electric vehicle including an in-wheel electric machine. FIG. 4 is a perspective view of an example implementation of the electric vehicle of FIG. 3. FIG. 5 is a side view of an example stator. FIG. 6 is an enlarged view of a portion of FIG. 5. FIG. 7 is a perspective view of an example edgewise coil. FIG. 8 is a perspective view of the edgewise coil of FIG. 7 positioned for radial loading onto a tooth of the stator of FIG. 5. FIG. 9 is another perspective view of the edgewise coil of FIG. 7 positioned for radial loading onto a tooth of th