Straddle Electric Vehicle Motor Layout for Compact Design

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Solution Overview

Problem

Straddle electric vehicles face challenges in compact layout design due to limited space, making it difficult to optimize the arrangement of on-vehicle parts.

Innovation Solution

The vehicle incorporates a motor case that accommodates an electric motor and output shaft, with the motor driving shaft located in front of and under the output shaft, allowing for a compact layout by aligning the motor and output shaft in an inclined direction, and utilizing a pivot frame with curved shape to maximize space efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the motor and output shaft are arranged in a conventional layout, then the driving force transmission is straightforward, but the vehicle size increases and compact layout becomes difficult

Engineering Contradiction:
Improvevehicle sizeVSAvoidlayout complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The motor driving shaft is positioned in front of and under the output shaft, creating a three-dimensional arrangement that utilizes vertical and longitudinal space more efficiently. This dimensional reorganization allows the motor case to be compact while maintaining the driving force transmission path, thereby reducing overall vehicle size without complicating the layout.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The motor case is designed to accommodate both the electric motor and the output shaft within a single integrated housing. The motor driving shaft is positioned to extend from the motor while the output shaft is located behind it, creating a nested arrangement where components share space efficiently, thus reducing the volume required for the motor assembly.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of manufacture

If the motor case is made larger to accommodate components comfortably, then component installation is easier, but the vehicle dimensions increase

Engineering Contradiction:
Improvecomponent installation easeVSAvoidvehicle length
Core Design Contradiction:
Ease of manufactureVSLength of stationary object

Solution Approach 1:

The motor case integrates the accommodation of the electric motor, output shaft, and motor driving shaft into a single unified structure. This merging of functions into one component eliminates the need for separate housings or mounting structures, thereby simplifying installation while maintaining a compact overall dimension that does not increase vehicle length.

Inventive Principle:
Principle #5Merging (Combining)

3Quantity of substance

If the battery arrangement space is increased, then battery capacity can be enhanced, but the vehicle size increases

Engineering Contradiction:
Improvebattery capacityVSAvoidvehicle size
Core Design Contradiction:
Quantity of substanceVSVolume of moving object

Solution Approach 1:

By positioning the motor driving shaft in front of and under the output shaft, the motor assembly occupies a compact three-dimensional space that does not extend significantly in the longitudinal direction. This creates available space in the vehicle floor area and vertical profile, allowing battery arrangement space to be increased without proportionally increasing overall vehicle size.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4311753A1Straddle electric vehicle
Publication Date: 2024.01.31 KAWASAKI MOTORS LTD
  • EP4311753A1 patent drawingFigure 1
  • EP4311753A1 patent drawingFigure 2
  • EP4311753A1 patent drawingFigure 3

AI summary

A straddle electric vehicle includes: a vehicle body frame; an electric motor including a motor driving shaft that outputs driving force by which a rear wheel is driven; a speed reducer that reduces the speed of the driving force of the motor driving shaft; an output shaft to which the driving force is transmitted from the speed reducer; an endless loop through which the driving force is transmitted from the output shaft to the rear wheel; and a motor case accommodating the electric motor and the output shaft. The motor driving shaft is located in front of and under the output shaft.