Housing Ventilation Member With Stress-Relieved Insertion Root
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Solution Overview
Problem
Conventional ventilation members for housings are prone to cracking on the inner circumferential surface of the insertion portion at the root, leading to potential detachment from the housing due to stress concentration.
Innovation Solution
The ventilation member design includes receding portions between the inner and outer circumferential surfaces at the root of the insertion portion, reducing stress concentration and preventing cracks, along with an air-permeable membrane and a support with a vent hole for airflow, and a sealing member for secure attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insertion portions are inserted into the opening while being elastically deformed radially inwardly and fixed to the opening, then the ventilation member can be securely attached to the housing, but the inner circumferential surface of the insertion portion may crack due to stress concentration
Solution Approach 1:
The patent applies local quality by creating a receding portion at a specific location (the root of the insertion portion) to redistribute stress. This local structural modification reduces stress concentration at the critical inner circumferential surface while maintaining the overall attachment function, thereby preventing cracks without compromising attachment security.
Solution Approach 2:
The receding portion is designed in advance as a preventive measure to reduce stress concentration before cracks can form. By pre-modifying the geometry of the insertion portion root, the design anticipates and prevents the stress concentration problem that would otherwise occur during elastic deformation and attachment.
2Ease of operation
If the insertion portions are made to elastically deform radially inwardly for insertion, then the ventilation member can be installed in the opening, but stress concentration at the root may lead to fracture and detachment
Solution Approach 1:
The receding portion creates a local structural feature at the insertion portion root that redistributes stress during elastic deformation. This local modification allows the insertion portion to maintain its elastic deformation capability for easy installation while preventing stress concentration that would lead to fracture and detachment.
3Device complexity
If the insertion portion has a uniform cross-section, then the structure is simple, but stress concentrates at the inner circumferential surface at the root during deformation
Solution Approach 1:
Instead of making the entire insertion portion complex, the patent applies a localized receding portion only at the root area where stress concentration occurs. This minimal structural modification reduces stress concentration without significantly increasing overall device complexity, maintaining simplicity while addressing the critical stress issue.
Solution Approach 2:
The receding portion introduces a dimensional variation in the radial direction at the insertion portion root. By creating this step-like feature that reduces the radial dimension at the critical location, the design redistributes stress in a way that prevents concentration at the inner circumferential surface.
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 prevents cracks on the inner circumferential surface of the insertion portion at the root, ensuring secure attachment and reduced risk of detachment while maintaining airflow through the housing.
Implementation Method 1
the insertion portions being adapted to be elastically deformed radially inwardly when the insertion portions are inserted into the opening and then to be fixed to the opening
Data Source
AI summary
The ventilation member of the present invention includes: a support; and an air-permeable membrane disposed on the support. The support includes: a base portion supporting the air-permeable membrane; and a leg portion extending from the base portion toward the interior space of a housing and adapted to fix the ventilation member to the opening of the housing. The leg portion includes: insertion portions separated from each other in a circumferential direction by slits formed between the insertion portions in an insertion start side of the leg portion, the insertion portions being adapted to be elastically deformed radially inwardly when the insertion portions are inserted into the opening and then to be fixed to the opening; and receding portions in the insertion portions. In a region between an edge of an inner circumferential surface of the insertion portion and an edge of an outer circumferential surface of the insertion portion at a root of the insertion portion, the receding portion recedes from an imaginary circumferential end surface in a direction away from the slit and recedes from an imaginary inner circumferential surface toward the outer circumferential surface, when the imaginary circumferential end surface is defined as an imaginary end surface including a central axis of the support and a first reference line parallel to the central axis and passing through the edge of the outer circumferential surface and the imaginary inner circumferential surface is defined as an imaginary surface extending in the circumferential direction from the edge of the inner circumferential surface toward the slit.