Lubricant-Supported Wheel-End Motor Assembly With Nested Planetary Drive
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Solution Overview
Problem
Current wheel-end electric motors for vehicular powertrain applications are heavy and bulky due to the need for robustness against shock and vibration, consuming valuable space and increasing weight, while also failing to adequately consider the tradeoffs between motor magnetic and electric structures and mechanical powertrain elements.
Innovation Solution
A modular lubricant-supported electric motor assembly comprising an electric motor module with a stator and rotor separated by a lubricant, a shifting and first stage module with a planetary gear reducer, and a final drive module, which provides adjustable drive torque and is designed to be compact, lightweight, and efficient, while maintaining compatibility with existing vehicle components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wheel-end electric motors incorporate large, heavy components to meet shock and vibration requirements, then robustness is improved, but weight and package volume increase
Solution Approach 1:
The patent combines the electric motor, planetary gear reducer, and final drive into a single integrated wheel-end assembly. This merging eliminates the need for separate heavy protective components by designing a unified structure where the motor housing itself provides the necessary robustness while containing all drive components, thereby reducing overall weight and package volume.
Solution Approach 2:
The patent nests the planetary gear reducer and final drive components within the motor housing and rotor assembly. The planetary gears are positioned inside the motor housing, and the final drive is integrated into the rotor structure, creating a compact nested arrangement that reduces package volume without requiring additional external protective structures.
2Reliability
If wheel-end electric motors incorporate large, heavy components to meet shock and vibration requirements, then robustness is improved, but package volume increases
Solution Approach 1:
The patent combines the electric motor, planetary gear reducer, and final drive into a single integrated wheel-end assembly. This merging eliminates the need for separate heavy protective components by designing a unified structure where the motor housing itself provides the necessary robustness while containing all drive components, thereby reducing overall weight and package volume.
Solution Approach 2:
The patent nests the planetary gear reducer and final drive components within the motor housing and rotor assembly. The planetary gears are positioned inside the motor housing, and the final drive is integrated into the rotor structure, creating a compact nested arrangement that reduces package volume without requiring additional external protective structures.
3Loss of energy
If prior art designs reduce ohmic losses and improve magnetics, then efficiency is improved, but tradeoffs with mechanical powertrain elements are not adequately considered
Solution Approach 1:
The patent integrates the electric motor, planetary gear reducer, and final drive into a single unified assembly where magnetic and mechanical elements are co-designed. The motor housing serves as both the structural support for the planetary gears and the housing for the electric motor, creating optimized interfaces between electromagnetic and mechanical components that reduce energy losses while managing complexity.
Solution Approach 2:
The motor housing performs multiple functions: it houses the electric motor, supports the planetary gear reducer, provides structural robustness for shock and vibration, and serves as the final drive housing. This multi-functionality eliminates the need for separate components and optimizes the integration between magnetic and mechanical powertrain elements.
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 lubricant-supported electric motor assembly achieves a smaller package size, lighter weight, higher torque and power density, and lower cost, while maintaining robustness against shock and vibration, and is compatible with existing vehicle systems without extensive redesign.
Implementation Method 1
A lubricant is disposed in the gap for supporting the rotor relative to the stator
Data Source
AI summary
A lubricant supported electric motor assembly includes an electric motor module, a shifting and first stage module, and a final drive module sequentially operably interconnected with one another for producing drive torque that is ultimately conducted to a wheel of a vehicle. The electric motor module includes a stator and a rotor defining an internal rotor cavity. The shifting and first stage module is disposed within the internal rotor cavity and includes a first planetary gear reducer assembly and an output gear selectively coupleable to said first planetary gear reducer assembly. The final drive module is disposed adjacent the shifting and first stage module and includes a second planetary gear reducer assembly operably coupled with the output gear. A shifting mechanism establishes selective coupling between the first planetary gear assembly and the output gear to transfer adjustable torque from the shifting and first stage module to the final drive device.