EV Drive Unit Controller Mounting to Limit Motor Heat Transfer
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Solution Overview
Problem
Integrated mechanical and electrical structures in electric vehicle drive units can suffer from heat transmission issues, where heat generated by the electric motor is likely to be transmitted to the controller, potentially leading to increased temperatures and reduced performance.
Innovation Solution
The drive unit incorporates a bracket that fixes the controller to the electric motor with a gap between them, and the controller is attached to the first and second housings supporting the bearings, rather than the stator case. This configuration reduces heat transmission from the electric motor's stator to the controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the controller is attached to the electric motor in an integrated mechanical and electrical structure, then high-voltage wiring can be shortened and cost reduced, but heat generated from the electric motor is likely to be transmitted to the controller
Solution Approach 1:
The patent divides the electric motor structure into distinct segments: the stator case (housing the heat-generating stator) and the end housings (supporting the controller). By segmenting the mounting structure, the controller is attached to the end housings rather than the stator case, creating thermal separation while maintaining structural integration. This segmentation allows the controller to be positioned close to the motor for wiring efficiency while preventing direct heat transmission paths.
Solution Approach 2:
The end housings act as intermediary components between the stator case and the controller. Instead of attaching the controller directly to the heat-generating stator case, the bracket system uses the end housings as intermediate mounting points. These intermediaries provide mechanical support and electrical connection pathways while breaking the direct thermal conduction path from the stator to the controller.
2Length of moving object
If the controller is attached close to the electric motor, then wiring length is reduced, but heat transmission increases
Solution Approach 1:
The patent applies local quality differentiation by providing thermal insulation specifically at the mounting points where the controller attaches to the end housings. Insulating members are placed locally at these critical interfaces to block heat transmission paths. This localized thermal management allows the controller to remain close to the motor for short wiring while protecting it from heat exposure through targeted insulation at the attachment points.
3Device complexity
If the bracket is attached to the stator case, then the structure is simplified, but heat is transmitted to the controller through the bracket
Solution Approach 1:
The patent extracts the controller mounting function from the stator case and relocates it to the end housings. By taking out the mounting attachment point from the heat-generating stator case and placing it on the non-heat-generating end housings, the design eliminates the thermal transmission path through the bracket while maintaining structural support. This extraction separates the thermal management function from the structural mounting function.
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
This design effectively reduces the amount of heat transmitted to the controller, thereby preventing overheating and improving the reliability and efficiency of the electric vehicle's drive unit, while also allowing for cost-effective production of various motor models.
Implementation Method 1
the bracket is attached to the first housing and the second housing and not to the stator case... the amount of heat that is transmitted from the stator to the controller is reduced
Data Source
AI summary
A drive unit includes an electric motor, an MCU to supply a driving current to the electric motor, and a bracket fixing the MCU to the electric motor with a gap between the MCU and the electric motor. The electric motor includes a stator case accommodating a stator, a first housing including a bearing that supports one side of an output shaft of a rotor, and a second housing including a bearing that supports another side of the output shaft of the rotor. The bracket supporting the MCU is attached to the first housing and the second housing and not to the stator case.