Straddle Electric Vehicle Motor Unit Positioning for Battery Space
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Solution Overview
Problem
Straddle type electric vehicles face limitations in cruising distance due to limited space for housing larger batteries, which restricts the vehicle's range.
Innovation Solution
The design includes a motor unit and battery supported by a main frame between the front and rear wheels, with the motor unit positioned overlapping the frame in a side view and the motor shaft disposed above and rearward of the pivot shaft, creating additional space for a larger battery while maintaining structural integrity and power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the battery capacity is increased to extend cruising distance, then the energy storage capability is improved, but the vehicle structure becomes more complex and space requirements increase
Solution Approach 1:
The motor shaft is positioned above the pivot shaft in the vertical dimension, creating three-dimensional space utilization. This vertical arrangement allows the battery to be placed in the space between the motor unit and the seat, effectively using vertical space to accommodate larger battery capacity without increasing horizontal footprint or structural complexity
2Use of energy by moving object
If a larger battery is installed to increase cruising distance, then the energy storage capability is improved, but the available housing space is insufficient
Solution Approach 1:
The battery is nested within the space created by the motor unit positioning. Specifically, the battery is placed in the void space between the motor unit (positioned above the pivot shaft) and the seat structure, effectively nesting the battery within existing structural voids rather than requiring additional dedicated housing space
3Volume of moving object
If the motor shaft is positioned above the pivot shaft, then the housing space for battery is increased, but the power transfer distance increases
Solution Approach 1:
The motor shaft is positioned above the pivot shaft in the vertical dimension rather than horizontally displaced, which increases housing space while minimizing the power transfer path length. The vertical alignment allows for a direct downward power transmission path to the swing arm and rear wheel, reducing energy loss despite the vertical displacement
Data Source
AI summary
A straddle type electric vehicle comprises a main frame, a motor unit including an electric motor, and a battery that supplies power to the motor unit. The main frame includes a left and right pair of portions. The motor unit is disposed overlapping the main frame in a side view of the vehicle. A motor shaft of the electric motor is disposed above the pivot shaft and rearward in the vehicle longitudinal direction.