Leaning Vehicle Link Mechanism for Compact Wheelbase

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The existing vehicle design with a body frame that can lean and two front wheels faces an issue where the size in the left-and-right direction is reduced, but the size in the front-and-rear direction is increased due to the link mechanism's inclination, leading to an enlarged wheelbase and interference with the front wheels.

Innovation Solution

The vehicle is configured with a link support portion that turns the upper and lower cross members at a smaller acute angle relative to the up-and-down direction, and a vertical frame portion with a front edge that is positioned closer to the rear wheels to reduce the rearward movement of the front wheels and minimize interference, allowing for a more compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If the link mechanism is configured with inclined upper and lower cross members to support the front wheels above them, then the size in the left-and-right direction is reduced, but the size in the front-and-rear direction is increased due to rearward wheel movement

Engineering Contradiction:
Improvesize in left-and-right directionVSAvoidsize in front-and-rear direction
Core Design Contradiction:
Area of moving objectVSLength of moving object

Solution Approach 1:

The patent changes the geometric parameters of the link mechanism, specifically making the upper and lower cross members substantially horizontal rather than inclined, and positioning them above the front wheels. This parameter change allows the front wheels to move vertically without significant rearward movement, resolving the contradiction between reducing left-and-right size and minimizing front-and-rear size.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Instead of positioning the cross members below the front wheels with inclined geometry (conventional approach), the patent inverts the arrangement by positioning the cross members above the front wheels with horizontal geometry. This inversion allows the link mechanism to achieve compactness in both left-and-right and front-and-rear directions simultaneously.

Inventive Principle:
Principle #13The other way round (Inversion)

2Ease of operation

If the vertical frame portion is positioned to avoid interference with the front wheels, then the front wheels can move freely, but the wheelbase is enlarged

Engineering Contradiction:
Improvefront wheel movement freedomVSAvoidwheelbase
Core Design Contradiction:
Ease of operationVSLength of moving object

Solution Approach 1:

The patent changes the position and orientation parameters of the vertical frame portion, positioning its front edge closer to the front wheels and orienting it at a specific angle. This allows the vertical frame portion to be closer to the front wheels without causing interference, thereby reducing the wheelbase while maintaining wheel movement freedom.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2923930B1vehicle
Publication Date: 2016.11.30 YAMAHA MOTOR CO LTD
  • EP2923930B1 patent drawingFigure 1
  • EP2923930B1 patent drawingFigure 2
  • EP2923930B1 patent drawingFigure 3

AI summary

The purpose of the present invention is to provide a vehicle comprising two front wheels and a vehicle frame capable of being inclined and capable of reducing the size of the vehicle in both the left/right direction and the front/rear direction. A link support section rotatably supports an upper cross member and a lower cross member, in a state in which the acute angle between a virtual plane vertical to the rotation axis of the upper cross member and the lower cross member and the up/down direction of the vehicle frame is smaller than the acute angle between the rotation axis of a steering shaft and the up/down direction of the vehicle frame. An upper/lower frame section is arranged such that the upper end of the forward edge thereof is parallel to the rotation axis of the steering shaft and is in front of a virtual plane that comes in contact with the rear sections of the right front wheel and left front wheel in vehicle upright state. The width in the left/right direction between the upper end and the lower end on the forward edge is formed so as to be smaller than the gap between the right front wheel and the left front wheel, and the acute angle between a virtual line passing through the upper end and the lower end and the up/down direction of the vehicle frame is formed so as to be smaller than the acute angle between the rotation axis of the steering shaft and the up/down direction of the vehicle frame.