Electric Vehicle Drive Device Integrated Power Supply Terminal
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Solution Overview
Problem
The existing power supply means for electric vehicle drive devices is complicated, leading to increased part count and size, and is prone to vibration-induced failures due to the use of independent power supply connectors.
Innovation Solution
The power supply terminal box is integrated into the housing, eliminating the need for an independent connector and providing a simplified structure that includes a partition between the electric motor and speed reduction unit, with a rotation angle sensor and lead wire terminal integrated into the housing, and bearings are symmetrically attached to prevent eccentric loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an independent power supply connector is used to supply power to the electric motor, then power delivery is achieved, but the structure becomes complicated and the connector may detach due to vibration
Solution Approach 1:
The power supply terminal box is integrated into the housing structure, merging two previously separate components (housing and power supply connector) into a single unified structure. This eliminates the independent connector that was prone to vibration-induced detachment, thereby improving reliability while reducing structural complexity.
2Use of energy by moving object
If multiple separate components (connector, terminal box, housing) are used for power supply, then power delivery function is achieved, but the number of parts increases and size increases
Solution Approach 1:
The housing and power supply terminal box are merged into a single integrated structure, reducing the number of separate parts. The power supply cable passes through the housing to connect to the terminal box that is now part of the housing, eliminating the need for a separate independent connector component.
3Ease of manufacture
If bearings are attached asymmetrically to the output member, then assembly is simplified, but eccentric loads cause mechanical instability
Solution Approach 1:
The patent applies symmetry principle (opposite of asymmetry) by attaching bearings symmetrically at both ends of the input shaft. The first bearing is attached to the housing on the inboard side, while the second bearing is attached to the output member on the outboard side, creating a balanced symmetric configuration that prevents eccentric loads and improves mechanical stability.
Data Source
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AI summary
An object of the present invention is to achieve reduction in cost and size of power supply means for an electric motor by obviating the need of a power supply connector therefor as an independent part. In a drive device for an electric vehicle including: a speed reduction unit 12 including an input shaft 13 driven by output of an electric motor 11; a hub unit 15 rotationally driven by an output member 14 of the speed reduction unit 12; and a housing 16 accommodating the electric motor 11 and the speed reduction unit 12, there is provided with a power supply terminal box 76 made up of: an accommodation recessed portion 94 provided in a rear end surface of the housing 16; a power supply terminal 82 provided inside the accommodation recessed portion 94; a communication hole 95 in communication with the accommodation recessed portion 94 and an interior of the housing 16; and a cover member 96 of the accommodation recessed portion 94.