Front Wheel Suspension Damper Positioning for Straddle Vehicles

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Solution Overview

Problem

Conventional front wheel supporting structures in vehicles with a swing arm mechanism have a damper member positioned low on the vehicle, leading to a low height from the road surface, reduced bank angle, and increased complexity due to longer distances and complicated structures.

Innovation Solution

The front wheel supporting structure positions the damper member rearward of the front wheel and head pipe, incorporates a link mechanism with a bell crank member, and uses additional front arms and connecting members to shorten the distance between the damper and the front arm, enhance responsiveness, and secure a larger bank angle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the damper member is disposed on the lower side of the front arm along the vehicle-width direction, then the structure is conventional and simple, but the height of the damper member from the road surface becomes low and a large bank angle cannot be secured

Engineering Contradiction:
Improvestructure complexityVSAvoidbank angle
Core Design Contradiction:
Device complexityVSShape

Solution Approach 1:

The damper member is repositioned from a lateral arrangement (vehicle-width direction) to a longitudinal arrangement (vehicle-length direction), specifically disposed between the front arm and the head pipe. This dimensional change in placement allows the damper to achieve a more optimal position that secures a larger bank angle while maintaining structural simplicity

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

2Device complexity

If the damper member is disposed on the lower side of the front arm, then the conventional structure is maintained, but the distance from the damper member to the arm supporting portion becomes long and the structure becomes complicated

Engineering Contradiction:
Improvestructure complexityVSAvoiddistance from damper to arm supporting portion
Core Design Contradiction:
Device complexityVSLength of stationary object

Solution Approach 1:

The damper member is extracted from its conventional position on the lower side of the front arm and repositioned to the space between the front arm and the head pipe. This extraction and relocation shortens the distance from the damper to the arm supporting portion, reducing structural complexity while maintaining the suspension function

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If the damper member is positioned with a long distance from the front arm, then the conventional layout is maintained, but the responsiveness of the damper member to vertical movement of the front wheel is reduced

Engineering Contradiction:
Improvedamper responsivenessVSAvoiddistance from damper to front arm
Core Design Contradiction:
ProductivityVSLength of stationary object

Solution Approach 1:

The damper member is preliminarily positioned in the optimal location between the front arm and the head pipe, where it can immediately and effectively respond to vertical movements of the front wheel. This preliminary placement ensures that the damper is always in the best position to provide suspension action, enhancing responsiveness

Inventive Principle:
Principle #10Preliminary action

4Object-affected harmful factors

If the damper member is disposed low from the road surface, then the conventional position is maintained, but pebbles flicked during running are more prone to hit the damper member

Engineering Contradiction:
Improvepebble impact on damperVSAvoidheight of damper from road surface
Core Design Contradiction:
Object-affected harmful factorsVSLength of stationary object

Solution Approach 1:

The head pipe serves as an intermediary structure that protects the damper member from pebble impact. By positioning the damper between the front arm and the head pipe, the head pipe acts as a shield, preventing pebbles flicked during running from directly hitting the damper member

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2743163B1Front wheel supporting structure for straddle-type vehicle
Publication Date: 2017.04.05 KAWASAKI JUKOGYO KK
  • EP2743163B1 patent drawingFigure 1
  • EP2743163B1 patent drawingFigure 2
  • EP2743163B1 patent drawingFigure 3

AI summary

A front wheel supporting structure for a vehicle comprises a front arm (10) for supporting a front axle (6) and a suspension mechanism (12) for resiliently suppressing vertical swinging motion of the front arm (10). The suspension mechanism includes a damper member (33) disposed along a lateral direction between a head pipe (1) and the front arm (10), and a connecting member (32, 34) for connecting the front arm (10) with the damper member (33) such that vertical swinging motion of the front arm (10) is converted into lateral motion of the damper member (33).