Straddle Vehicle Tail Cover with Expanded Portions for Splash Deflection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional straddle-type vehicles face a dilemma in preventing splashes from the rear wheel while maintaining a lightweight rear section, as increasing the tail cover width to prevent splashes increases the vehicle's mass, and decreasing it allows splashes to reach the rider.

Innovation Solution

The design incorporates a mud catcher positioned rearward and above the rear wheel, with expanded portions on either side of the tail cover that extend outward and downward, and through holes between these portions to allow airflow, which catches and deflects splashes, ensuring the tail lamp's visibility and reducing the rear section's weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the width of the tail cover is increased to prevent splashes from coming into contact with the rider, then splash prevention is improved, but the mass of the rear portion of the vehicle is increased

Engineering Contradiction:
Improvesplash contact with riderVSAvoidmass of rear portion
Core Design Contradiction:
Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The tail cover is divided into a main body portion and separate expanded portions on the right and left sides. This segmentation allows the expanded portions to extend laterally to prevent splashes while keeping the main body compact, thus preventing splash contact without significantly increasing the overall mass of the rear portion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of uniformly increasing the width of the tail cover, the design adds lateral expansion in the width direction at specific locations (right and left expanded portions). This dimensional change allows splash prevention functionality to be added without proportionally increasing the mass of the entire rear portion.

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

2Weight of moving object

If the measurement in the vehicle width direction of the tail cover is decreased to reduce weight, then the weight of the rear portion is decreased, but splashes are likely to come into contact with the rider

Engineering Contradiction:
Improveweight of rear portionVSAvoidsplash contact with rider
Core Design Contradiction:
Weight of moving objectVSObject-affected harmful factors

Solution Approach 1:

The tail cover is segmented into a main body with limited width and separate expanded portions that extend laterally. This allows the main body to remain compact for weight reduction while the expanded portions provide the necessary lateral coverage to prevent splash contact with the rider.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The expanded portions are strategically positioned at the right and left sides of the tail cover where splash prevention is most needed. This local quality enhancement provides targeted protection against splashes without requiring a uniform increase in the width of the entire tail cover, thus maintaining weight efficiency.

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If the measurement in the vehicle width direction of the tail cover is increased to prevent splashes, then splash prevention is improved, but the visibility of emitted light of the tail lamp unit may be compromised

Engineering Contradiction:
Improvesplash preventionVSAvoidvisibility of tail lamp light
Core Design Contradiction:
Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The tail cover is segmented with expanded portions that extend laterally away from the central tail lamp unit. This segmentation allows the expanded portions to provide splash prevention coverage without obstructing the light emission path of the tail lamp, thus maintaining both splash prevention and light visibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The expanded portions are positioned asymmetrically on the right and left sides of the tail cover, extending outward from the central axis where the tail lamp is located. This asymmetric arrangement provides lateral splash protection while maintaining a clear central region for optimal tail lamp visibility.

Inventive Principle:
Principle #4Asymmetry

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 effectively prevents splashes from reaching the rider while maintaining a lightweight rear section and improving airflow to reduce air resistance, enhancing the riding experience.

Implementation Method 1

An air stream flows through the right through hole and the left through hole during the travelling of the vehicle. Thus, splashes splashed by the rear wheel are blown off to a position further rearward than the vehicle by the air stream passing through the right through hole and the left through hole.

Methodology Applied
Scientific EffectAir stream flow: Convection

Data Source

PatentEP2955090B1Straddle type vehicle
Publication Date: 2016.06.29 YAMAHA MOTOR CO LTD
  • EP2955090B1 patent drawingFigure 1
  • EP2955090B1 patent drawingFigure 2~3
  • EP2955090B1 patent drawingFigure 4

AI summary

A mud guard (40) and a tail lamp unit (33) are provided above a rear wheel (10). A tail cover unit (30) includes a tail cover (31) and a pair of right and left expanded portions (32). The pair of expanded portions (32) is provided at the right and left of the tail cover, respectively. Through holes (PS), which extend in a front-and-rear direction, are formed between a pair of side surfaces (312) of the tail cover and inner surfaces of the pair of expanded portions (32), respectively. A measurement (W3) in a vehicle width direction of the mud guard (40) is smaller than a measurement (W4) in the vehicle width direction from an outer end of the one expanded portion to an outer end of the other expanded portion, and is larger than a measurement (W2) in the vehicle width direction of the tail cover.