Integrated Drive Case Layout for Larger Inverter Packaging
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Solution Overview
Problem
The axial size of the inverter housing portion in existing vehicle drive devices is limited by mating surfaces between housing components, leading to increased size and manufacturing costs due to the need for multiple fastening and sealing members.
Innovation Solution
A vehicle drive device with a case design where the joint surface between the case body and cover member is located on one side in the axial direction, allowing for a larger inverter housing chamber and reducing the number of components by integrating the case body and cover member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional transmission system with multiple components (transmission case, differential case, bearings, gears) is used, then power transmission function is achieved, but the number of parts increases and assembly complexity increases
Solution Approach 1:
The patent combines the transmission case and differential case into a single integrated case structure. The transmission gears, planetary gears, and differential mechanism are all housed within this unified case, eliminating the need for separate transmission and differential cases. This merging reduces the number of parts and assembly steps while maintaining the power transmission function.
Solution Approach 2:
The single case structure serves multiple functions: it acts as the transmission case housing, the differential case housing, and provides mounting surfaces for both transmission gears and planetary differential components. This multi-functional design reduces overall system complexity while ensuring reliable power transmission through all mechanisms.
2Ease of manufacture
If multiple separate cases (transmission case, differential case) are used, then functional separation is achieved, but assembly steps increase and manufacturing cost increases
Solution Approach 1:
The patent integrates the transmission case and differential case into one unified structure, eliminating the need to manufacture and assemble separate cases. This single case is manufactured as one piece or pre-assembled unit, reducing manufacturing steps and costs while simplifying the overall assembly process.
3Volume of moving object
If a compact gear arrangement is used, then space utilization is improved, but gear meshing precision becomes difficult to ensure
Solution Approach 1:
The patent employs a planetary gear system where gears rotate on multiple axes simultaneously. The planetary gears engage with both the sun gear and ring gear, creating dynamic meshing relationships that maintain precise tooth contact despite compact dimensions. This dynamic gear arrangement achieves compact space utilization while preserving gear meshing precision through the inherent geometry of planetary engagement.
Data Source
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AI summary
A case (1) includes: a case body (11) forming a first housing chamber (5) housing a rotating electrical machine (MG) and gears (G) and a second housing chamber (3) housing an inverter device (INV); and a cover member (12). The cover member (12) is joined to an axial second side (L2) of the case body (11), and disposed to cover the axial second side (L2) of the first housing chamber (5). The case body (11) includes a partition wall (70) separating the first housing chamber (5) and the second housing chamber (3), a peripheral wall (61) covering the first housing chamber (5) from outside in a radial direction (R), and an axial wall (62) covering an axial first side (L1) of the second housing chamber (5). The partition wall (70), the peripheral wall (61), and the axial wall (62) are integrally formed.