Leaning Vehicle Tread Width Adjustment Mechanism

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Solution Overview

Problem

Existing leaning vehicles face challenges in changing tread width without compromising steering properties or operational feel, often requiring additional components like adaptors which can affect inertial moment and tire wear.

Innovation Solution

A leaning vehicle design featuring a link mechanism with offset leaning axes and interchangeable side members that change the tread width by altering the position of front wheels relative to the body frame, maintaining parallelism with ground contact surfaces to minimize steering interference and inertial changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If adaptors are mounted on front wheels to change tread width, then tread width is adjusted, but inertial moment changes and steering properties are compromised

Engineering Contradiction:
Improvetread width adjustmentVSAvoidsteering properties
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The link mechanism is divided into interchangeable left and right side members that can be independently configured. Each side member has offset leaning axes that can be positioned at different distances from the steering axis, allowing tread width adjustment while maintaining balanced inertial properties through symmetric configuration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The side members utilize asymmetric offset leaning axes relative to the steering axis to achieve tread width adjustment. The offset distance creates the necessary geometric relationship for wheel positioning while the symmetric arrangement of left and right side members maintains overall vehicle balance and minimizes inertial changes.

Inventive Principle:
Principle #4Asymmetry

2Adaptability or versatility

If conventional link mechanisms are used to change tread width, then wheel positions are adjusted, but steering interference increases due to non-parallel ground contact

Engineering Contradiction:
Improvetread width adjustmentVSAvoidsteering operation
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The design changes the geometric parameters of the link mechanism by configuring the offset leaning axes at specific distances from the steering axis. This parameter optimization ensures that when the vehicle leans, the ground contact points of the front wheels remain parallel to the original ground contact line, eliminating steering interference during tread width adjustment.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If additional components like adaptors are added to change tread width, then tread width is adjusted, but device complexity increases

Engineering Contradiction:
Improvetread width adjustmentVSAvoidmechanism structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The interchangeable side members serve multiple functions: they adjust tread width, maintain steering properties, and preserve inertial balance simultaneously. By integrating the offset leaning axis configuration directly into the side members rather than using separate adaptors, the mechanism achieves multi-functionality without increasing overall device complexity.

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

Data Source

PatentEP3620361B1Leaning vehicle
Publication Date: 2020.12.09 YAMAHA MOTOR CO LTD
  • EP3620361B1 patent drawingFigure 1
  • EP3620361B1 patent drawingFigure 2
  • EP3620361B1 patent drawingFigure 3

AI summary

By exchanging positions of the first side member (11) and the second side member (12), one of a first state and a second state is selected to change a tread width of a leaning vehicle. At least one of an upper left leaning axis (LUL) and a lower left leaning axis (LDL) is offset from a left steering axis (SL) in the left-right direction of the body (21) frame as viewed from the front-rear direction of the body frame. At least one of an upper right leaning axis (LUR) and a lower right leaning axis (LDR) is offset from a right steering axis (SR) in the left-right direction of the body frame as viewed from the front-rear direction of the body frame. In any case where the first state or the second state is selected, following conditions are established. An offset amount in association with the left side member is equal to an offset amount in association with the right side member. A left straight line (L1) connecting the upper left leaning axis (LUL) and the lower left leaning axis (LDL) overlaps a ground contact surface of a left front wheel (31) as viewed from the front-rear direction of the body frame. A right straight line (L2) connecting the upper right leaning axis (LUR) and the lower right leaning axis (LDR) overlaps a ground contact surface of a right front wheel (32) as viewed from the front-rear direction of the body frame.