Straddled Vehicle Power Unit With Overlapping Electric Motor Support

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Solution Overview

Problem

The existing straddled vehicles with a power unit including a continuously variable transmission and an electric motor face challenges in maintaining a compact structure and easy maintenance, particularly due to the extended length of the power unit in the up-down direction, which affects foot grounding and seat positioning, making it difficult for the driver to reach the ground.

Innovation Solution

The straddled vehicle design includes a power unit that supports the rear wheel at both ends with a first support, where the electric motor is positioned to overlap the support in a side view, allowing for a more compact layout by integrating the electric motor outside the crankcase and using a cylindrical portion and plate portion for support, with easy installation and maintenance features.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the electric motor is disposed higher than the first support or the first support is disposed higher than the electric motor, then the power unit includes both the electric motor and first support, but the length of the power unit in the up-down direction becomes long

Engineering Contradiction:
Improvepower unit structureVSAvoidpower unit length in up-down direction
Core Design Contradiction:
Device complexityVSLength of stationary object

Solution Approach 1:

The patent transitions from vertical stacking (up-down direction) to horizontal overlapping (front-rear direction) by positioning the electric motor to overlap the first support in side view. This dimensional change allows both components to coexist without increasing the power unit's height, thereby reducing the length in the up-down direction while maintaining structural integrity.

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

2Device complexity

If the power unit is disposed at a relatively high position due to long length in up-down direction, then the seat is disposed at a relatively high position, but it becomes difficult for the driver to reach the ground with the foot

Engineering Contradiction:
Improvepower unit configurationVSAvoidfoot grounding property
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

By repositioning the electric motor to overlap the first support horizontally rather than vertically, the power unit's height is reduced. This allows the power unit and seat to be positioned lower, improving the driver's ability to reach the ground while maintaining all necessary functional relationships between components.

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

3Device complexity

If the rear wheel is supported only at one end by the power unit (cantilevered), then the structure is simplified, but the rear wheel is not supported at both ends

Engineering Contradiction:
Improverear wheel support structureVSAvoidrear wheel support stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The first support structure is designed to serve multiple functions: it supports the rear arm, provides mounting for the electric motor, and contributes to supporting the rear wheel at both ends. This multi-functional design achieves dual-end support without significantly increasing structural complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4596384A1Straddled vehicle
Publication Date: 2025.08.06 YAMAHA MOTOR CO LTD
  • EP4596384A1 patent drawingFigure 1
  • EP4596384A1 patent drawingFigure 2
  • EP4596384A1 patent drawingFigure 3

AI summary

A straddled vehicle (1) includes a vehicle body frame (3), a power unit (11), a rear arm (53), and a rear wheel (55). The power unit (11) swings with respect to the vehicle body frame (3). The rear arm (53) swings with respect to the vehicle body frame (3). The rear wheel (55) is supported by the power unit (11) and the rear arm (53). The power unit (11) includes an engine (12), a continuously variable transmission (21), an electric motor (31), and a first support (41). The engine (12) generates power. The continuously variable transmission (21) transmits power of the engine (12) to the rear wheels (55). The electric motor (31) changes the gear ratio of the continuously variable transmission (21). The first support (41) supports the rear arm (53). At least a part of the electric motor (31) overlaps the first support (41) in vehicle side view.