Leaning Vehicle Shock Tower Layout for Tire Positioning Freedom

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Solution Overview

Problem

Existing leaning vehicles face challenges in increasing the degree of freedom regarding the positions of tires in the vehicle body frame while maintaining the size reduction of the shock absorber tower and link mechanism, and enhancing the rigidity of the support mechanism for the shock absorber tower.

Innovation Solution

The shock absorber tower is positioned further forward or backward in the vehicle-body-frame direction than the arm-member supported parts, avoiding interference and allowing for a reduction in size and increased design freedom of the mechanism, with a focus on maintaining rigidity through tensile load characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the shock absorber tower is positioned between the arm-member supported parts, then the mechanism size is reduced and rigidity is enhanced, but the degree of freedom regarding tire positions is limited

Engineering Contradiction:
Improvedegree of freedom regarding tire positionsVSAvoidmechanism size and configuration flexibility
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The shock absorber tower is repositioned from a horizontal arrangement (between arm-member supported parts) to a vertical arrangement (above or below them in the vehicle-body-frame up-down direction). This dimensional change allows the tower to occupy space in the vertical dimension rather than the horizontal dimension, thereby increasing freedom in tire positioning while maintaining compact mechanism size.

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

2Adaptability or versatility

If the shock absorber tower is repositioned to increase tire positioning freedom, then adaptability is improved, but the rigidity of the support mechanism may be compromised

Engineering Contradiction:
Improvetire positioning freedomVSAvoidrigidity of support mechanism
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

By moving the shock absorber tower to the vertical dimension (above or below arm-member supported parts), the patent maintains structural rigidity through the vertical support path while freeing up horizontal space for enhanced tire positioning flexibility. The tower's vertical orientation preserves its load-bearing capability.

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

Solution Approach 2:

The support mechanism is segmented into distinct vertical and horizontal functional zones: the shock absorber tower handles vertical load support in the up-down direction, while the arm-member supported parts handle horizontal positioning. This segmentation allows each component to optimize its function without compromising overall rigidity or adaptability.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If the shock absorber tower is positioned to avoid interference with arm members, then ease of manufacture is improved, but the mechanism size may increase

Engineering Contradiction:
Improveinterference avoidanceVSAvoidmechanism volume
Core Design Contradiction:
Ease of manufactureVSVolume of moving object

Solution Approach 1:

The shock absorber tower is relocated to the vertical dimension (above or below arm-member supported parts), utilizing the up-down direction to avoid horizontal interference with arm members during movement. This dimensional separation eliminates the need for complex interference-clearance designs while maintaining compact overall mechanism volume.

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

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration allows for increased freedom in tire positioning, reduced mechanism size, and maintained rigidity of the support mechanism for the shock absorber tower, facilitating easier design modifications and interference avoidance.

Implementation Method 1

The shock absorber tower is supported by the vehicle body frame so as to rotate around a tower central shaft that extends in the vehicle-body-frame front-back direction

Methodology Applied
Scientific EffectRotation:

Implementation Method 2

The left arm mechanism swings in the vehicle-body-frame upward direction when the vehicle body frame leans in the leaning-vehicle leftward direction, and swings in the vehicle-body-frame downward direction when the vehicle body frame leans in the leaning-vehicle rightward direction

Methodology Applied
Scientific EffectMechanical linkage motion:

Implementation Method 3

The left shock absorber has a cushioning action. A first end part of the left shock absorber is connected to the upper-left arm member or the lower-left arm member

Methodology Applied
Scientific EffectCushioning: Damping

Data Source

PatentEP3623270B1Leaning vehicle
Publication Date: 2025.07.02 YAMAHA MOTOR CO LTD
  • EP3623270B1 patent drawingFigure 1
  • EP3623270B1 patent drawingFigure 2
  • EP3623270B1 patent drawingFigure 3

AI summary

An object of the present invention to provide a leaning vehicle in which the degree of freedom regarding the positions of tires in the vehicle body frame can be increased while also reducing the size of a mechanism that includes a shock absorber tower and a link mechanism and maintaining the rigidity of a support mechanism for the shock absorber tower in the vehicle body frame. In a leaning vehicle 1 according to the present invention, a shock absorber tower (57) is disposed further forward in a vehicle-body-frame (21) frontward direction f than an upper-left-arm-member supported part (511) at which an upper-left arm member (51) to which a first end part (331) of a left shock absorber (33) is connected is supported by the vehicle body frame (21), and an upper-right-arm-member supported part (531) at which an upper-right arm member (53) to which a first end part (341) of a right shock absorber (34) is connected is supported by the vehicle body frame (21).