Composite Drive Unit Housing for Electric Vehicles
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Solution Overview
Problem
Current electric vehicle drive unit housings made from cast aluminum are heavy and fail to adequately reduce noise, vibration, and harshness (NVH) while maintaining gear alignment and proper gear meshing.
Innovation Solution
A composite shell drive unit housing with a structural support skeleton that includes a plurality of annular bearing support portions and a composite shell molded to the skeleton, utilizing materials like continuous fiber composites and polymers to enhance stiffness and reduce weight, while also providing electromagnetic interference (EMI) shielding and electrical grounding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If cast aluminum housing is used, then structural strength is sufficient, but weight is excessive and NVH performance is inadequate
Solution Approach 1:
The patent applies composite materials by combining a metal structural support skeleton with a composite shell material (such as carbon fiber reinforced polymer). This composite construction reduces housing weight while the specific material properties of the composite shell provide superior NVH performance compared to traditional cast aluminum housings.
2Weight of moving object
If composite materials are used to reduce weight, then weight is reduced, but structural stiffness between bearings may be insufficient
Solution Approach 1:
The housing is segmented into two functional parts: a metal structural support skeleton that provides critical structural stiffness and bearing support, and a composite shell that reduces weight and provides NVH benefits. This segmentation allows each material to optimize its specific function without compromising overall performance.
Solution Approach 2:
The patent uses composite materials in a hybrid construction where the metal skeleton maintains structural stiffness between bearings while the composite shell reduces overall weight. The combination leverages the high stiffness-to-weight ratio of metals for structural support and the low density of composites for weight reduction.
3Weight of moving object
If complex composite structure is implemented, then weight and NVH are improved, but manufacturing complexity increases
Solution Approach 1:
By dividing the housing into a metal skeleton and composite shell, the patent simplifies the manufacturing process compared to creating a fully complex composite structure. The metal skeleton can be manufactured using conventional processes, and the composite shell is molded separately then attached, reducing overall manufacturing complexity while achieving weight and NVH benefits.
Data Source
AI summary
An electric motor drive unit including an electric motor having an output shaft and a plurality of gears in driving engagement with the output shaft. The plurality of gears being supported by a plurality of laterally spaced bearings. A composite housing member includes a structural support skeleton supporting multiple ones of the plurality of laterally spaced bearings and a composite shell molded to the structural support skeleton.