Gear Housing Snap-Fastener Design for Deflection Control
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Solution Overview
Problem
Actuator housing components with snap-fit fasteners are prone to damage during handling and assembly, requiring excessive fasteners that increase manufacturing costs and complexity due to undesirable deflection caused by worm gear forces.
Innovation Solution
A snap-fit fastener system featuring a clip and lug design with a U-shaped plate portion and elastic properties, minimizing the number of fasteners needed and protecting the fasteners from damage by integrating them within the housing components, ensuring secure assembly without excessive deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If snap-fit fastener components are used to join housing cover and container, then assembly is simple and can be performed without tools, but the fastener components may protrude from edge portions and break during handling
Solution Approach 1:
The fastener components are nested within recesses formed in the housing container and cover. The clip is received within a recess in the container, and the lug is received within a recess in the cover, preventing protrusion and breakage while maintaining snap-fit assembly simplicity
Solution Approach 2:
Recesses are introduced as intermediary structures that accommodate the fastener components, protecting them from damage during handling while allowing them to function properly during assembly
2Strength
If five or six fasteners are used to retain cover on container, then the cover is securely retained against separation forces, but the number of fasteners increases the likelihood of damage and measurement effort
Solution Approach 1:
Multiple fastener functions are merged into fewer, more robust fastener components positioned to handle the separation forces generated by the worm gear, reducing the total number of fasteners needed while maintaining retention strength
Solution Approach 2:
The fasteners are positioned at strategic locations that optimize their ability to resist separation forces, changing the spatial arrangement from a simple distributed pattern to a optimized configuration that reduces the number of fasteners required
3Strength
If fasteners are positioned at gear housing sidewalls, then they provide retention, but the distance from force application at gear shaft causes excessive deflection of the cover
Solution Approach 1:
The fasteners are repositioned from the sidewalls to the free edge of the container, changing their spatial location to a position that minimizes cover deflection while maintaining retention capability against separation forces
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 securely joins housing components with reduced risk of damage during handling and assembly, minimizing the number of fasteners required while preventing undesirable deflection, thus enhancing manufacturability and assembly efficiency.
Implementation Method 1
The latch bar has a first end, a second end that is opposed to the first end, an outer edge that extends between the first end and the second end in a direction perpendicular to the axis and an inner edge that is parallel to the outer edge
Data Source
AI summary
A housing a housing container, a housing cover configured to close an open end of the housing container and a snap-fit fastener that secures a rim of the housing cover to a sidewall of the housing container. The housing container includes a base and a sidewall that protrudes from the base. The fastener includes an elastic clip that is disposed on an outer surface of the sidewall and a rigid lug that protrudes from the cover and engages the clip. The clip has a U-shaped plate portion that extends in parallel to the sidewall and defines clip opening. The lug includes a ridge that protrudes into the clip opening and engages the plate portion. The plate portion is dimensioned so that an outer edge of the plate portion is disposed no further from the container base than the sidewall free edge.