Vehicle Door Mirror Visor Airflow Control for Wind Noise Reduction
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Solution Overview
Problem
Vehicular visual recognition devices, such as exterior rearview mirrors, experience noise issues like wind noise and whistling due to airflow entering through openings during vehicle travel.
Innovation Solution
The design incorporates a trunk portion with an opening for the optical axis, covered by an outer peripheral member with a peripheral wall, and a wall portion at the rear side of the opening, which directs airflow to minimize noise by creating a narrow and bent airflow path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an opening is formed in the outer peripheral member for the optical axis to pass through, then the viewing function is improved, but noise generation increases due to airflow entering the interior
Solution Approach 1:
A airflow control member is introduced as an intermediary element between the opening and the interior space. This member selectively allows optical signals to pass through while blocking or redirecting airflow, thereby mediating between the viewing function requirement and the noise reduction requirement
Solution Approach 2:
The outer peripheral member is designed with different local properties: the opening portion maintains high transparency for optical signals, while the airflow control portion provides aerodynamic functionality to block or redirect air flow. This local differentiation allows simultaneous achievement of viewing function and noise suppression
2Illumination intensity
If the opening portion is made larger to improve optical performance, then viewing quality is improved, but wind noise and whistling increase
Solution Approach 1:
The opening portion is segmented into multiple smaller openings or sub-apertures arranged in a specific pattern. This segmentation maintains sufficient total optical transmission area for good viewing quality while reducing the continuous open area that causes wind noise and whistling effects
Solution Approach 2:
The airflow control member acts as a mediator that allows optical signals to pass through the segmented openings while blocking or redirecting air flow, thereby enabling larger effective optical area without proportional increase in noise
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 noise generation by redirecting airflow, reducing the amount of air entering the interior and thus minimizing wind noise and whistling during vehicle travel.
Implementation Method 1
a wall portion that is provided at the trunk portion, and that, at a vehicle rear side portion of the opening portion, faces the peripheral wall at a radial direction side of the opening portion
Data Source
AI summary
An opening (irradiation opening (90A)), which faces an opening portion of an outer peripheral member and through which an optical axis of an optical member (lamp unit (46)) passes, is formed in a trunk portion (88) that, together with a viewing means (door mirror) for assisting viewing by a vehicle occupant of a vehicle, is covered by the outer peripheral member (visor cover). Further, a wall portion (106), which runs along a peripheral wall of the opening portion and, at a vehicle rear side portion, faces the peripheral wall at a radial direction side, is formed at the trunk portion. Air, which enters into the opening portion while the vehicle is traveling, passes-through a flow path that is bent by the peripheral wall and the wall portion, and the flow rate is reduced, and noise is suppressed.