Outer Mirror Peripheral Groove for Wind Noise Suppression
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Solution Overview
Problem
Wind noise is generated by the resonance of airflow through the gap between the mirror plate and mirror visor in vehicle outer mirrors, leading to increased noise levels.
Innovation Solution
A peripheral groove is provided along the peripheral edge of the mirror plate, which reduces wind noise by attenuating sound waves reflected within the groove.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a gap is provided between the mirror plate and mirror visor, then the mirror plate can be installed and adjusted, but wind noise is generated by airflow resonance through the gap
Solution Approach 1:
The peripheral edge of the mirror plate is segmented by forming a peripheral groove that divides the gap into multiple sub-gaps. This segmentation disrupts the airflow path and prevents resonance, reducing wind noise while maintaining the necessary gap for mirror plate installation and adjustment.
Solution Approach 2:
The peripheral groove acts as an intermediary structure between the mirror plate and mirror visor. It modifies the airflow characteristics in the gap region, transforming the continuous gap into a structured path that reduces resonance while still allowing for mechanical adjustment.
2Object-generated harmful factors
If the gap between mirror plate and mirror visor is reduced, then wind noise is reduced, but mirror plate installation and adjustment become difficult
Solution Approach 1:
Instead of reducing the overall gap size, the peripheral groove segments the gap into smaller sub-gaps. This maintains the total gap width needed for installation and adjustment while creating multiple narrow flow paths that reduce resonance and wind noise.
3Object-generated harmful factors
If the peripheral groove width varies from opening toward bottom, then sound wave attenuation is enhanced, but manufacturing complexity increases
Solution Approach 1:
The peripheral groove has varying width along its length, with the width changing from the opening toward the bottom. This local variation optimizes sound wave attenuation at different positions, creating better noise reduction performance while the groove can still be formed using standard molding or machining techniques.
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
The peripheral groove effectively suppresses wind noise by interfering with airflow and attenuating sound waves, thereby reducing noise generation.
Implementation Method 1
The peripheral groove provided in the peripheral edge of the mirror plate reduces wind noise generated by an airflow passing through a gap between the mirror plate and the mirror visor. The sound waves repeatedly reflected in the peripheral groove are attenuated.
Data Source
AI summary
The outer mirror includes a mirror plate and a mirror visor surrounding the mirror plate. The mirror visor has a peripheral wall portion facing the peripheral edge of the mirror plate with a gap therebetween. A peripheral groove extending along the direction in which the peripheral edge extends is formed in the peripheral edge of the mirror plate. The peripheral groove has a triangular cross-sectional shape and opens toward the peripheral wall portion.