Automotive Register Fin Serration and Chamfering for Wind Noise Reduction
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Solution Overview
Problem
Conventional air outlet registers for automobile ventilation and air conditioning experience increased wind noise when the movable fin is turned significantly upward, downward, leftward, or rightward due to increased contact area with flat surfaces, leading to eddying flows and noise amplification.
Innovation Solution
A register design featuring a serrated portion with roundly chamfered angle portions on the upstream edge of the fins, reducing flat surfaces and promoting air flow along curved surfaces, thereby minimizing eddying flows and wind noise, with specific configurations for radius of curvature, serration height, pitch, and fin width to maintain directivity and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the movable fin is turned significantly upward, downward, leftward, or rightward from the front side, then the air blowing direction is adjusted to meet occupant needs, but the contact area of air with flat surfaces in the thickness direction of the movable fin increases, causing air flows to synchronize and form large eddying flows that increase wind noise
Solution Approach 1:
The patent applies curvature by forming roundly chamfered angle portions at the edges of the movable fin. This replaces sharp flat edges with curved surfaces, causing air flows to follow the curved path rather than synchronizing on flat surfaces. The curved surfaces disrupt the formation of large eddying flows by creating irregular flow patterns, thereby reducing wind noise while maintaining adjustable air blowing direction functionality
Solution Approach 2:
The patent segments the edge portion of the movable fin by forming multiple notched portions and roundly chamfered angle portions along the edge. This segmentation breaks up the continuous flat surface into discrete segments, preventing air flows from synchronizing across the entire edge. The segmented structure creates multiple small irregular flow zones that cancel each other out, reducing overall wind noise
2Object-generated harmful factors
If a serration structure is formed on the edge portion of the movable fin, then small-sized eddying flows are formed to reduce wind noise, but when the fin is turned at large angles, the increased contact area with flat surfaces causes air flows to synchronize and form large eddying flows again
Solution Approach 1:
The patent enhances the serration structure by adding roundly chamfered angle portions to the edges of each serration. This curvature modification ensures that even when the fin is turned at large angles, the air flows encounter curved surfaces rather than flat edges, preventing synchronization of air flows. The curved serrations maintain small-sized eddying flows across all turning angles, making the noise reduction effective throughout the full range of fin motion
Solution Approach 2:
The patent applies different surface qualities to different parts of the movable fin. The main surface of the fin remains relatively flat for effective air direction control, while the edge portions feature notched portions and roundly chamfered angle portions to disrupt air flow synchronization. This local differentiation allows the fin to maintain adaptability across all turning angles while specifically addressing wind noise at the critical edge regions where air flow separation occurs
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 design effectively reduces wind noise by minimizing eddying flows when the fins are turned, while maintaining air directivity and preventing resonance sounds, through the use of serrated and chamfered features that disrupt airflow synchronization.
Implementation Method 1
a serrated portion including a large number of juxtaposed serrations is formed on an edge portion on an upstream side of the fin, and angle portions forming outlines of all of the serrations are roundly chamfered to form chamfered portions on the entire outlines
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Provided is a register capable of reducing wind noise when movable fins are largely turned upward, downward, leftward, or rightward from the front side. In a register, a ventilation passage (21) is provided inside a retainer (2) so as to communicate with an air outlet (11) of a bezel (1), and inside the air outlet (11), a front movable louver (3) and a rear movable louver (5) constituting a cross fin type register are provided by disposing fins (50) orthogonal to each other. On an edge portion on an upstream side of the fin (50), a serrated portion (60) including a large number of juxtaposed serrations (61) is formed, and all angle portions forming outlines of all serrations (61) are roundly chamfered to form chamfered portions (62) on the entire outlines.