Electric Motorcycle Cable Harness Layout for Easier Motor Mounting

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Solution Overview

Problem

The existing straddled electric vehicles face difficulties in workability due to the restricted length of the power cable connecting the drive circuit and electric motor, which limits the sequential mounting of these components on the body frame.

Innovation Solution

A straddled electric vehicle design featuring a first cable harness with a forward-located portion and a curved configuration, allowing for a sufficient length and reduced load on the power cables, while maintaining a compact layout and preventing vehicle width increase, with the motor unit positioned behind the motor drive unit and battery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the drive circuit and electric motor are connected with a power cable before mounting on the body frame, then electrical connection is established, but the mounting workability is restricted due to cable length limitations

Engineering Contradiction:
Improveelectrical connectionVSAvoidmounting workability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The cable harness is routed through the longitudinal direction of the vehicle body, utilizing the length dimension rather than only the lateral dimension. This allows the cable to reach from the drive circuit to the motor unit even when both components are mounted on opposite sides of the body frame, resolving the contradiction between establishing electrical connection and maintaining mounting workability.

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

2Ease of operation

If the motor unit and motor drive unit are positioned far apart to accommodate cable length, then mounting flexibility is improved, but the vehicle width increases

Engineering Contradiction:
Improvemounting flexibilityVSAvoidvehicle width
Core Design Contradiction:
Ease of operationVSLength of moving object

Solution Approach 1:

Instead of positioning components far apart in the lateral dimension to accommodate cable length, the solution routes the cable through the longitudinal dimension of the vehicle body. This allows compact lateral positioning of the motor unit and drive circuit while maintaining mounting flexibility through sufficient cable length routed along the body's length.

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

Solution Approach 2:

The cable harness includes a curved portion with a radius of curvature greater than three times the cable diameter, allowing the cable to bend smoothly around the battery and other components. This curved routing enables the cable to reach between components positioned close together laterally without increasing vehicle width, while maintaining mounting flexibility.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP3812619A1Straddled electric vehicle
Publication Date: 2021.04.28 YAMAHA MOTOR CO LTD
  • EP3812619A1 patent drawingFigure 1
  • EP3812619A1 patent drawingFigure 2
  • EP3812619A1 patent drawingFigure 3

AI summary

To improve workability of attaching a motor drive unit and a motor unit to a vehicle body, an electric two-wheeled vehicle 1 includes a battery 50, a motor unit 40, a motor drive unit 30, and a first cable harness 61 for electrically connecting an electric motor 41 and a drive circuit 31 and sending power of the battery 50 from the drive circuit 31 to the electric motor 41. The motor unit 40 is disposed behind the motor drive unit 30. The first cable harness 61 has, in a middle thereof, a portion (margin portion 61e) located forward than a front surface 36g of the motor drive unit 30.