Vehicle Mirror Seal Lip Design for Wind Noise Reduction
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Solution Overview
Problem
Existing mirror assemblies for vehicle side doors face wind noise issues due to gaps between the housing and support arm, which are exacerbated by hard seal members that compromise sealing performance and hinder folding motion.
Innovation Solution
A seal member formed from a single unitary rubber material with obliquely extended seal lips is used, compressible between the inner and outer base members, allowing for flexible engagement with both the support arm and housing to seal gaps while enabling unrestricted movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hard seal member is used to minimize interference with housing folding motion, then ease of operation is improved, but sealing performance deteriorates due to assembly tolerances creating leak paths
Solution Approach 1:
The seal member material hardness is changed from hard to soft, allowing it to deform and conform to assembly tolerances while maintaining sealing effectiveness. The soft material enables the seal lips to adapt to slight misalignments between housing and support arm, eliminating leak paths without restricting folding motion.
Solution Approach 2:
The seal member is constructed from composite or multi-material rubber composition with varying durometer levels - softer regions for sealing contact surfaces and slightly harder regions for structural integrity. This allows the seal to simultaneously provide effective sealing against tolerances while maintaining flexibility for folding operation.
2Reliability
If a soft seal member is used to maintain sealing performance, then reliability is improved, but ease of operation deteriorates due to resistance against folding motion
Solution Approach 1:
The seal member exhibits local quality variations with different material properties in different regions. The seal lips contacting the housing and support arm use softer material for effective sealing, while the body portion has slightly higher durometer to reduce resistance to folding motion. This localized property differentiation resolves the contradiction between sealing effectiveness and operational ease.
Solution Approach 2:
The seal member is designed with dynamic characteristics that allow it to be soft during static sealing conditions but exhibit reduced resistance during dynamic folding operation. The material composition and geometric design enable the seal to flex and yield during folding motion while maintaining sealing contact, effectively adapting its mechanical properties to the operational state.
3Ease of operation
If a gap is provided between housing and support arm to allow folding motion, then ease of operation is improved, but object-affected harmful factors worsen due to wind noise
Solution Approach 1:
The seal member acts as an intermediary element positioned in the gap between the housing and support arm. It physically bridges the gap, blocking wind noise transmission while still permitting the housing to fold. The seal member's flexible material allows it to accommodate folding motion while maintaining the noise-blocking function, effectively mediating between the conflicting requirements of motion freedom and noise reduction.
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 solution effectively reduces wind noise and maintains sealing performance by using a flexible seal member that allows for the housing's folding motion without compromising the seal, addressing the limitations of hard seal members in existing technologies.
Implementation Method 1
The seal member includes a base at least partially compressed by one of the support arm and the housing
Implementation Method 2
The seal member is formed of a single unitary rubber material
Data Source
AI summary
An external mirror assembly for a vehicle includes a support arm adapted to be affixed to an associated vehicle side door, and a housing movably connected to the support arm via a pivoting structure. The pivoting structure is connected to the support arm and to a bracket supported within the housing. A seal member surrounds the connection of the housing to the support arm. The seal member includes a base at least partially compressed by one of the support arm and the housing. The seal member includes an outer periphery portion defining a first seal lip and an inner periphery portion defining a second seal lip. One of the first seal lip and the second seal lip is configured to sealingly engage the support arm and the other of the first seal lip and the second seal lip configured to sealingly engage the housing.