Thermally enhanced hub motor

• US 9,755,485 B1
• Filed: 02/15/2017
• Issued: 09/05/2017
• Est. Priority Date: 03/07/2016
• Status: Active Grant

• Current Assignee: Future Motion, Inc.
• Original Assignee: Future Motion, Inc.
• Inventors: Doerksen, Kyle Jonathan, Blachinsky, Dan, de la Rua, Julian, Hancock, Clyde
• Primary Examiner(s): Gurari, Erez
• Application Number:
  US15/433,194
• Publication Number:
  US 20170257008A1
• Time in Patent Office: 202 Days
• CPC Class Codes: A62C 27/00 Fire-fighting land vehicles
• CPC Class Codes: B07C 3/12 using electric or electronic detecting means B07C3/14 takes precedence
• CPC Class Codes: B60K 7/0007 the motor being electric
• CPC Class Codes: B60L 50/64 Constructional details of batteries specially adapted for electric vehicles
• CPC Class Codes: B62K 1/00 Unicycles
• CPC Class Codes: B62K 11/007 Automatic balancing machines with single main ground engaging wheel or coaxial wheels supporting a rider
• CPC Class Codes: B62K 11/02 Frames motorcycles or cycles with auxiliary engines characterised by position of engine B62M
• CPC Class Codes: B62K 2202/00 Motorised scooters
• CPC Class Codes: B62M 7/12 with the engine beside or within the driven wheel
• CPC Class Codes: H02K 1/187 to inner stators
• CPC Class Codes: H02K 15/02 of stator or rotor bodies
• CPC Class Codes: H02K 5/02 Casings or enclosures characterised by the material thereof
• CPC Class Codes: H02K 9/223 Heat bridges
• CPC Class Codes: H02K 9/227 Heat sinks
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles

Abstract

Apparatuses and methods relating to hub motors having enhanced thermal characteristics may include a hub motor having a stator comprising steel and a central axle (e.g., a mandrel and shaft) comprising a material with a substantially higher thermal conductivity than the stator (e.g., aluminum). Heat may be transferred from the stator through the axle of the motor to an outside heat sink. Manufacturing of thermally enhanced hub motors may include extrusion and/or cryogenic fitting methods relating to the central mandrel and shaft.

Claims

1. An electric vehicle comprising:

a frame;

a wheel assembly including a rotatable ground-contacting element;

a hub motor configured to rotate the ground-contacting element to propel the electric vehicle, the hub motor including;

a rotor,

a stator disposed concentrically within the rotor, such that the rotor is configured to rotate about the stator, and

an axle portion formed as a single piece and coupled to the frame, the axle portion having a central shaft extending axially from a mandrel fixed concentrically within the stator, an outer surface of the mandrel in direct contact with the stator;

wherein the axle portion consists of a single material having a thermal conductivity substantially higher than the stator, and the mandrel is connected to the central shaft by a plurality of radial connection members that are unitary with the mandrel and the central shaft.

2. The vehicle of claim 1, wherein the stator comprises steel, and the axle consists of an aluminum alloy.

3. The vehicle of claim 1, wherein the mandrel is cylindrical.

4. The vehicle of claim 1, wherein the central shaft is in direct contact with the frame.

5. The vehicle of claim 1, wherein the mandrel has two opposing end portions, and the central shaft extends axially from both of the end portions of the mandrel.

6. The vehicle of claim 1, wherein the mandrel is disposed concentrically within the stator in an interference fit.

7. An electric vehicle comprising:

a frame;

at least one wheel assembly coupled to the frame and including a rotatable ground-contacting element;

a hub motor corresponding to each wheel assembly and configured to rotate the corresponding ground-contacting element to propel the electric vehicle, each hub motor including;

a stator disposed concentrically within the ground-contacting element, and

an axle portion formed as a single piece having a central shaft extending axially from a mandrel fixed concentrically within the stator, the mandrel having an outer diameter larger than the central shaft, an outer surface of the mandrel in direct contact with the stator, the central shaft and the mandrel comprising material having a thermal conductivity higher than a thermal conductivity of the stator;

wherein the axle portion of each hub motor is in thermal communication with the frame, and the mandrel is connected to the central shaft by a plurality of radial connectors unitary with the mandrel and the central shaft.

8. The vehicle of claim 7, wherein the central shaft and mandrel comprise an aluminum alloy.

9. The vehicle of claim 7, wherein the frame comprises aluminum.

10. The vehicle of claim 7, wherein the mandrel has an outer diameter larger than the central shaft.

11. The vehicle of claim 10, wherein the mandrel is cylindrical.

12. The vehicle of claim 7, wherein the axle portion of each hub motor is directly coupled to the frame.

13. The vehicle of claim 7, wherein the at least one wheel assembly includes two wheel assemblies.

14. The vehicle of claim 7, wherein the vehicle is chosen from the set consisting of an electric scooter, an electric bicycle, and a self-balancing electric vehicle.

15. An electric vehicle comprising:

a frame;

at least one wheel assembly coupled to the frame and including a rotatable ground-contacting element;

a hub motor corresponding to each wheel assembly and configured to rotate the corresponding ground-contacting element to propel the electric vehicle, each hub motor including;

a stator disposed concentrically within the ground-contacting element, and

an axle portion formed as a single piece having a central shaft extending axially from a mandrel fixed concentrically within the stator, the mandrel having an outer diameter larger than the central shaft, an outer surface of the mandrel in direct contact with the stator, the central shaft and the mandrel comprising material having a thermal conductivity higher than a thermal conductivity of the stator;

wherein the axle portion of each hub motor is in thermal communication with the frame, the axle portion of each hub motor further comprises a connection block, and the central shaft is coupled to the frame through the connection block.

16. The vehicle of claim 15, wherein the axle portion extends from opposing sides of the stator.

17. The vehicle of claim 15, wherein the frame comprises aluminum.

18. The vehicle of claim 15, wherein the axle portion consists essentially of an aluminum alloy.

19. The vehicle of claim 15, wherein the mandrel is disposed concentrically within the stator in an interference fit.