Electric Drive Unit Terminal Integration for Miniaturization
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Solution Overview
Problem
The existing electric drive units for vehicles, as described in JP 2019-036436 A, face challenges in miniaturization due to the number of parts required for electrical connections between the AC motor and power converter, which also hinders the replaceability of power converter components.
Innovation Solution
The electric drive unit design includes a multi-phase AC motor and a power converter with terminals that are directly connected via fasteners through an electric motor case, reducing the number of parts and space required for electrical connections while maintaining the replaceability of the power converter by using a service hole for fastening, allowing the power converter to be fixed to the motor case without additional parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional parts (terminal blocks, connectors, cables) are used to connect AC motor and power converter terminals, then electrical connection reliability is improved, but the number of parts increases and space is consumed
Solution Approach 1:
The patent merges multiple separate connection components (terminal blocks, connectors, cables) into a single integrated terminal structure. The AC motor terminals and power converter terminals are directly connected through a unified terminal assembly that is fixed to the motor case, eliminating the need for intermediate connection parts while maintaining electrical connection reliability.
Solution Approach 2:
The patent extracts and eliminates unnecessary intermediate connection components from the electrical connection system. By removing terminal blocks, connectors, and cables that were previously required, the design achieves direct terminal-to-terminal connection between the AC motor and power converter, reducing part count while preserving connection functionality.
2Reliability
If additional parts (terminal blocks, connectors, cables) are used to connect AC motor and power converter terminals, then electrical connection reliability is improved, but space is consumed hindering miniaturization
Solution Approach 1:
The patent merges multiple separate connection components (terminal blocks, connectors, cables) into a single integrated terminal structure. The AC motor terminals and power converter terminals are directly connected through a unified terminal assembly that is fixed to the motor case, eliminating the need for intermediate connection parts while maintaining electrical connection reliability.
Solution Approach 2:
The patent repositions the power converter to partially overlap the AC motor in the axial direction, utilizing the radial space within the motor housing. This dimensional arrangement allows the terminals to be connected directly without requiring additional axial space for intermediate connectors and cables, thereby reducing the overall volume of the electric drive unit.
3Device complexity
If terminals are directly connected via fasteners through motor case, then number of parts is reduced and space is saved, but replaceability of power converter parts may be compromised
Solution Approach 1:
The patent segments the terminal connection structure into modular components: the terminal assembly is separately fixable to the motor case via service holes, and the power converter is separately fixable to the motor case. This segmentation allows the power converter to be removed and replaced independently while maintaining the terminal connection infrastructure, thus preserving replaceability while reducing overall part count.
Solution Approach 2:
The patent incorporates service holes and fastening structures into the motor case in advance during manufacturing. These pre-prepared connection points allow for easy assembly and disassembly of the power converter and terminal components, facilitating future maintenance and part replacement without requiring complex disassembly procedures.
4Ease of repair
If power converter is fixed to motor case with direct terminal connection, then replaceability of power converter is improved, but additional fastening structures are required
Solution Approach 1:
The patent designs the service holes and fastening structures to serve multiple functions: they are used during initial assembly to secure the terminal assembly and power converter to the motor case, and they are also used during maintenance to facilitate quick removal and replacement of the power converter. This multi-functionality reduces the need for separate fastening mechanisms while improving replaceability.
Data Source
AI summary
An electric drive unit includes a multi-phase AC motor including a plurality of first terminals, and a power converter including a plurality of second terminals. The power converter is fixed to an electric motor case so as to partially overlap the AC motor in an axial direction with a wall portion interposed therebetween. Each first terminal includes a first extended portion extending from the stator along the axial direction, and a first fastening portion. Each second terminal includes a second extended portion extending along an extending direction at a portion of the power converter that does not overlap the AC motor in the axial direction; and a second fastening portion. The electric motor case includes a communication hole formed in the wall portion, and a service hole formed in a portion located on an extension line of the fastener parallel to an insertion direction of the fastener.