Propulsion Wheel Motor with Integrated Liquid Cooling
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Solution Overview
Problem
Existing electric vehicle wheel assemblies with individual propulsion systems lack a compact and modular solution for independent control and efficient cooling, leading to increased maintenance costs and complexity.
Innovation Solution
A propulsion-braking module integrated within the wheel rim, featuring a direct torque transmission system, liquid cooling with a metal foam heat conductor, and a modular design with a cam-based braking system, allowing for independent wheel control and simplified maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a compact propulsion system is integrated within the wheel rim, then independent wheel control and vehicle flexibility are improved, but the device complexity increases
Solution Approach 1:
The patent combines the propulsion motor, braking system, cooling mechanism, and wheel rim into a single integrated propulsion-braking module. The motor is mounted directly to the wheel rim, and the braking system is incorporated within the same housing, eliminating the need for separate propulsion and braking systems. This merging approach enables independent wheel control while managing device complexity through functional integration.
Solution Approach 2:
The propulsion-braking module serves multiple functions: it provides propulsion through the electric motor, braking through the cam-actuated brake shoes, cooling through the liquid circulation system, and structural support as a wheel rim. This multi-functionality allows a single device to replace multiple separate systems, improving adaptability while controlling complexity.
2Temperature
If a liquid cooling system with metal foam heat conductor is implemented, then heat management efficiency is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent employs metal foam as a heat conductor within the cooling system. The porous structure of the metal foam provides a large surface area for heat transfer between the motor/stator and the circulating liquid, significantly improving heat management efficiency. The metal foam is integrated into the housing structure, allowing thermal management without requiring separate complex heat exchanger components.
Solution Approach 2:
The cooling system uses liquid circulation through channels formed in the housing to remove heat from the motor and stator. The hydraulic flow path is integrated into the structural housing, eliminating the need for separate piping systems. The liquid cooling approach provides efficient thermal management while maintaining a compact design.
3Ease of repair
If a modular propulsion-braking module design is adopted, then maintenance time and costs are reduced, but the initial device complexity increases
Solution Approach 1:
The propulsion system is designed as a modular propulsion-braking module that can be removed and replaced as a single unit. The module includes the motor, braking system, cooling mechanism, and wheel rim as an integrated assembly. This segmentation allows the entire propulsion system to be replaced without disassembling individual components, significantly reducing maintenance time and costs despite the initial complexity of creating the modular architecture.
4Loss of energy
If a direct torque transmission system with 1:1 ratio is used, then mechanical efficiency is improved, but the loss of torque control flexibility increases
Solution Approach 1:
The direct torque transmission system with 1:1 ratio eliminates the need for complex gear trains or torque conversion mechanisms. The motor rotor is directly connected to the wheel rim, allowing the motor to self-regulate torque output based on vehicle needs without energy loss through mechanical transmission components. This self-service approach maintains mechanical efficiency while the control system adjusts motor current to provide the required torque flexibility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The module provides flexible and efficient control of vehicle maneuvers, reduces maintenance time and costs, and ensures effective heat management through liquid cooling, while the modular design facilitates easy installation and replacement.
Implementation Method 1
The heat conductor is operable to transfer heat from the stator to the cooling liquid
Implementation Method 2
The inner water jacket housing is operable to circulate a cooling liquid circumferentially about an outer radial surface of the inner water jacket housing
Implementation Method 3
The heat conductor includes a metal foam
Implementation Method 4
The propulsion-braking module includes an electric motor having a rotor rotatable about the central axis, and a stator disposed radially inside the rotor
Implementation Method 5
Each of the pair of brake shoes includes a friction surface that is operable to engage a radial inner surface of the brake drum
Data Source
AI summary
A wheel assembly for an electric vehicle includes a wheel rim that is concentrically disposed about a central axis. A propulsion-braking module is disposed within an interior region of the wheel rim. The propulsion-braking module rotatably supports the wheel rim for rotation about the central axis. The propulsion-braking module includes a liquid cooled electric motor having a rotor rotatable about the central axis, and a stator disposed radially inside the rotor relative to the central axis. A motor-wheel interface hub is fixedly attached to the wheel rim, and is directly attached to the rotor for rotation with the rotor. The motor-wheel interface hub directly transmits torque from the electric motor to the wheel rim at a 1:1 ratio. The propulsion-braking module includes a drum brake system having an electric motor that rotates a cam device, which actuates the brake shoes.