Straddle Vehicle Mudguard Connection Member Design

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Solution Overview

Problem

Straddle-type vehicles face challenges in providing sufficient protection against mud and ensuring the rigidity of the mudguard, particularly when the mudguard and rear fender are molded in one piece using a resin material, which can lead to insufficient rigidity and weight issues due to increased length.

Innovation Solution

A straddle-type vehicle design featuring a metal connection member with obliquely extending side walls and covered openings, connected to the seat frames forward of the rear flashers, which provides improved protection and rigidity while reducing weight by using a lightweight resin plate to cover the openings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the mudguard length in the front-rear direction is increased to provide sufficient protection against mud, then mud protection is improved, but the rigidity of the mudguard becomes insufficient due to the resin material

Engineering Contradiction:
Improvemud protectionVSAvoidmudguard rigidity
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent combines a metal connection member (high rigidity) with a resin mudguard (lightweight) to create a composite structure. The metal connection member provides the necessary rigidity support while the resin mudguard extends in length to provide adequate mud protection, resolving the contradiction between length and rigidity.

Inventive Principle:
Principle #40Composite materials

2Strength

If a metal connection member is used to ensure rigidity of the mudguard, then rigidity is improved, but the weight of the straddle-type vehicle increases

Engineering Contradiction:
Improvemudguard rigidityVSAvoidvehicle weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies metal material locally only where rigidity is critically needed (in the connection member between the mudguard and rear fender), while the rest of the mudguard remains lightweight resin. This localized use of heavy material minimizes weight increase while ensuring rigidity where necessary.

Inventive Principle:
Principle #3Local quality

3Weight of moving object

If the connection member is made small in size to reduce weight, then vehicle weight is reduced, but the protection against water and/or mud splashed from the rear wheel becomes insufficient

Engineering Contradiction:
Improvevehicle weightVSAvoidmud protection
Core Design Contradiction:
Weight of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent extends the connection member in the width direction (lateral dimension) rather than only in the front-rear direction. This dimensional change allows the connection member to provide effective mud protection by covering the wheel area laterally while keeping the front-rear length compact, thus maintaining low weight.

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

Data Source

PatentEP2949558B1Straddle-type vehicle
Publication Date: 2016.06.15 YAMAHA MOTOR CO LTD
  • EP2949558B1 patent drawingFigure 1
  • EP2949558B1 patent drawingFigure 2
  • EP2949558B1 patent drawingFigure 3

AI summary

A straddle-type vehicle (1) including right and left rear flashers (64R, 64L) disposed forward relative to a tail light (60), a metal connection member (70) disposed under the tail light (60), connected to right and left seat frames (40R, 40L) at positions forward relative to the right and left rear flashers (64R, 64L), and extending rearward from the right and left seat frames (40R, 40L), and a mudguard (80) connected to the connection member (70) wherein the connection member (70) includes a first left side wall extending obliquely downward and leftward from a first upper wall and including a first opening, and a first right side wall extending obliquely downward and rightward from the first upper wall and including a second opening and the first and second openings are covered with a plate member (90) molded of a resin material.