Electric Vehicle Drive Unit Width Reduction via Vertical Motor Orientation
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Solution Overview
Problem
The existing drive systems for electric vehicles, which integrate a motor and reducer, face challenges in reducing vehicle width dimensions due to the motor's size protrusion from the wheel recess, making it difficult to design compact vehicles, especially for smaller vehicles where space is limited.
Innovation Solution
The proposed solution involves a vertically-swingable upper and lower arm structure connected to the vehicle body frame, with the drive unit, including an integrated electric motor and reducer, positioned in a way that the motor shaft overlaps a line extending from the wheel's rotation center, and the reducer is partially housed within the wheel's recessed portion, allowing for a more compact design by optimizing the placement of components within the vehicle width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the motor size is increased to provide greater drive power, then the drive power is improved, but the motor protrudes more from the wheel recess toward the vehicle width center, increasing the vehicle width dimension
Solution Approach 1:
The patent repositions the motor from a horizontal arrangement (protruding toward vehicle width center) to a vertical arrangement (extending in the vehicle height direction). The motor is disposed above the upper arm with its axis extending in the vehicle width direction, allowing the drive unit to increase in size without increasing vehicle width dimension. This dimensional transition resolves the contradiction between drive power and vehicle width.
2Device complexity
If the motor and reducer are integrated to reduce component count, then device complexity is reduced, but the integrated unit protrudes more from the wheel recess, increasing vehicle width dimension
Solution Approach 1:
The integrated motor-reducer unit is positioned vertically above the upper arm rather than horizontally at the wheel recess. The motor case and reducer case are arranged in the vehicle height direction, with the motor shaft extending in the vehicle width direction. This vertical placement eliminates the protrusion problem while maintaining the integration benefits.
Solution Approach 2:
The motor is disposed within the space above the upper arm, nested within the vehicle body structure. The motor case is positioned such that it does not protrude beyond the vehicle width boundaries, effectively nesting the drive unit within the available vertical space rather than horizontal space.
3Length of stationary object
If the motor is positioned to overlap the wheel recess to reduce vehicle width, then vehicle width dimension is reduced, but the motor shaft cannot be properly aligned with the wheel rotation center for efficient power transmission
Solution Approach 1:
The motor shaft is positioned to extend in the vehicle width direction and overlap the line from the wheel rotation center, achieving proper alignment for power transmission. Meanwhile, the motor case itself is positioned above the upper arm in the vehicle height direction, so it does not protrude horizontally. This separates the shaft alignment requirement from the motor housing position.
Data Source
AI summary
A drive unit and a rear cushion overlap each other in a vehicle front view. Since the rear cushion is disposed to overlap the drive unit, the dimension in a vehicle width direction can be made smaller than that in the case where the cushion is disposed on the vehicle width center side of the drive unit.