HVAC Door Sealing Surface Graining for Low-Noise Operation
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Solution Overview
Problem
Conventional HVAC systems in vehicles experience noise issues due to high friction between elastomer doors and case surfaces as they rotate, leading to audible sounds during position changes.
Innovation Solution
The implementation of a grained surface on the case touch area, which reduces the frictional force between the elastomer door and the case by minimizing the effective contact area, thereby reducing the energy required to move the door and minimizing noise output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a smooth elastomer edge is used to facilitate sealing between the door and case, then sealing effectiveness is improved, but friction and noise increase during door movement
Solution Approach 1:
The patent applies different surface qualities to different regions of the case. The sealing surface (case touch area) is grained to reduce friction, while other areas maintain their original smooth finish. This localized modification allows the elastomer to seal effectively against the grained surface without experiencing excessive friction during movement.
Solution Approach 2:
The patent changes the surface roughness parameter of the case touch area by applying a grain pattern. This parameter change reduces the coefficient of friction between the elastomer and the case surface, thereby reducing noise and friction during door operation while maintaining sealing effectiveness.
2Adaptability or versatility
If the door is made rotatable to control airflow volume, then airflow control capability is improved, but friction-based noise is generated during position changes
Solution Approach 1:
The grained surface is applied specifically to the case touch area where the elastomer contacts the case during rotation. This localized treatment allows the door to rotate freely for airflow control without generating noise at the contact interface.
3Reliability
If the elastomer contacts the case along a surface contact area for sealing, then sealing effectiveness is improved, but the energy required to move the door increases
Solution Approach 1:
By changing the surface roughness parameter of the case touch area through graining, the coefficient of friction is reduced. This allows the elastomer to maintain surface contact for sealing while requiring less energy to initiate and maintain door movement.
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 grained surface effectively reduces noise levels by more than 5 dBA when the door transitions from a closed to an open position while maintaining a seal to prevent air leakage, enhancing passenger comfort.
Implementation Method 1
The grained surface on the case touch area reduces the frictional force between the elastomer door and the case by minimizing the effective contact area
Implementation Method 2
Each door may include an elastomer along one or more sides of the door to facilitate sealing between one-side of the door and the case to restrict any air leakage to the other side
Data Source
AI summary
Disclosed is an HVAC system configured to reduce noise. The HVAC system includes a door having a first and second end. The door includes an elastomer along the first end and a rotatable member adjacent the second end. The elastomer includes a door touch area. The case defines an internal case portion, external case portion, and a case opening fluidly connecting the internal and external case portion. The case is configured to receive the rotatable member of the door such that the door is rotatable about an axis between a first position, where the door covers the case opening, and a second position, where the door does not cover the case opening. The case includes a case touch area with a graining. The door touch area and the case touch area are substantially parallel and in contact along a surface contact area when the door is in the first position.