Straddle-Type Vehicle Front Shield With Recesses For Wind Noise

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Solution Overview

Problem

Conventional front structures for straddle-type vehicles with shields positioned above the front cowl and a clearance between them fail to adequately improve aerodynamic characteristics and reduce wind noise, particularly in vehicles where the shield stands more upright than the front cowl.

Innovation Solution

A front structure featuring a shield with recessed portions along its fundamental curved surface, a narrow portion created by notching inward, and a central opening, supported by a meter stay that also functions as a visor, which directs wind flow to reduce the joining of winds at different velocities and enhance windbreak effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a shield is provided on an upper part of a front cowl with a clearance between them, then the vehicle can accommodate different vehicle types (tourer vehicles), but aerodynamic characteristics and wind noise reduction are insufficient

Engineering Contradiction:
Improvevehicle type accommodationVSAvoidwind noise
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The shield is designed with recess portions at specific locations (left and right parts) to create local variations in surface geometry. These recess portions modify the airflow pattern locally, reducing the joining of upper and lower traveling winds with different flow velocities, thereby suppressing wind noise while maintaining the overall shield structure and vehicle type adaptability

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If a shield is provided on an upper part of a front cowl with a clearance between them, then the vehicle can accommodate different vehicle types (tourer vehicles), but aerodynamic characteristics are insufficient

Engineering Contradiction:
Improvevehicle type accommodationVSAvoidair resistance
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The recess portions are strategically positioned at the left and right parts of the shield to locally modify airflow characteristics. This local geometric modification reduces turbulence and improves aerodynamic flow patterns, decreasing air resistance and energy loss while preserving the shield's overall function and vehicle type versatility

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If notch portions are formed by notching the shield inward to create a narrow portion, then the shield can reduce wind noise at higher positions, but the shield structure becomes more complex

Engineering Contradiction:
Improvewind noise at high positionVSAvoidshield structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The shield is segmented by forming notch portions that create a narrow portion with a central opening. This segmentation divides the shield structure into distinct regions (left and right parts with recess portions, and a central opening), allowing targeted airflow control at different locations. The segmentation enables effective wind noise reduction at high positions while maintaining a manageable structural complexity through systematic design

Inventive Principle:
Principle #1Segmentation

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 suppresses wind noise and air resistance, maintains turning performance, and reduces wind power against occupants, achieving improved aerodynamics and windbreak similar to a taller shield with fewer components.

Implementation Method 1

the shield is formed along a fundamental curved surface (61W) that causes a wind during traveling to flow to the left and right of the vehicle body

Methodology Applied
Scientific EffectAerodynamic flow: Aerodynamic Heating

Implementation Method 2

the recess portions being recessed from the fundamental curved surface (61W) are arranged at left and right parts of the shield (61)... reduce the joining of upper and lower traveling winds that are located at the left and right parts of the shield and different in flow velocity

Methodology Applied
Scientific EffectFlow separation: Flow Separation

Implementation Method 3

an upper surface of the meter stay (101) is formed in a shape that causes a wind having flowed through the shield opening (61Y) to flow upward

Methodology Applied
Scientific EffectAerodynamic flow guidance: Aerofoil

Implementation Method 4

the shield (61) is provided with a narrow portion (61S) where the shield is narrowed in a vehicle width-wise direction by notch portions (61A)... the air volume of a traveling wind to flow to the left and right in the narrow portion is reduced

Methodology Applied
Scientific EffectFlow constriction: Venturi Effect

Data Source

PatentEP3059149B1Front structure of straddle-type vehicle
Publication Date: 2018.12.05 HONDA MOTOR CO LTD
  • EP3059149B1 patent drawingFigure 1
  • EP3059149B1 patent drawingFigure 2
  • EP3059149B1 patent drawingFigure 3(A)~3(B)

AI summary

A front structure of a straddle-type vehicle enabling suppression of wind noise includes a shield (61) that is provided on an upper part of a front cowl (54) with a clearance between them. The shield (61) is formed along a fundamental curved surface (61W) that causes a wind during traveling to flow to the left and right of a vehicle body, and shield recess portions (61X), recessed from the fundamental curved surface (61W), are arranged at left and right parts of the shield (61).