Segmented Socket Hole Geometry for Easier Nut Fitting
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Solution Overview
Problem
Existing electrical device assemblies face challenges in easily fitting nuts or bolt heads into socket holes due to positional and directional difficulties, which complicates the integration of electrical devices and resin members, particularly in insert molding processes.
Innovation Solution
The electrical device assembly incorporates a socket hole with an inclined guide surface and a housing portion, featuring segmented partitions that guide the nut or bolt head into position, ensuring easy fitting regardless of orientation, and includes arc-shaped corner portions to distribute rotational torque and prevent stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a simple cylindrical socket hole is used, then the manufacturing process is simple, but it is difficult to fit the nut properly due to positional and directional issues
Solution Approach 1:
The guide surface is divided into multiple segments (first guide surface segment, second guide surface segment, third guide surface segment) with different inclinations. Each segment handles a specific phase of the nut insertion process: the first segment receives the nut at a gentle angle, the second segment guides it deeper, and the third segment directs it to the final position. This segmentation resolves the contradiction by maintaining manufacturing simplicity while enabling proper nut fitting through functional division of the guide surface.
Solution Approach 2:
Different portions of the guide surface have different inclinations tailored to specific functions. The first guide surface segment has a first inclination, the second segment has a second inclination, and the third segment has a third inclination. This local differentiation allows each region to optimize for its specific task in the nut insertion process, resolving the contradiction between simple manufacturing and easy operation.
2Device complexity
If the guide surface has uniform inclination, then the structure is simple, but stress concentrates at corner portions causing damage
Solution Approach 1:
The guide surface features asymmetric corner portions (first corner portion, second corner portion, third corner portion) with different radii of curvature at different locations. This asymmetric design prevents stress concentration by distributing mechanical loads more evenly across the guide surface during nut insertion, resolving the contradiction between structural simplicity and reliability.
Solution Approach 2:
Corner portions of the guide surface are designed with curved surfaces having specific radii of curvature instead of sharp angles. The first corner portion has a first radius of curvature, the second corner portion has a second radius of curvature, and the third corner portion has a third radius of curvature. This curvature eliminates stress concentration points while maintaining overall structural simplicity.
3Manufacturing precision
If precise alignment features are added to the socket hole, then nut fitting precision improves, but the manufacturing process becomes more complex
Solution Approach 1:
The guide surface is designed with dynamic geometric progression through multiple segments with different inclinations. As the nut progresses through the socket hole, it encounters progressively steeper angles that naturally guide it to the correct final position. This dynamic approach achieves precise positioning through the inherent geometry of the insertion process rather than requiring additional static alignment features.
Solution Approach 2:
The guide surface segments are pre-configured with specific inclinations that perform the alignment action during the insertion process itself. The first, second, and third guide surface segments progressively orient the nut to the correct position before it reaches the housing portion, eliminating the need for post-insertion alignment adjustments or complex pre-alignment features.
Data Source
AI summary
In an electrical device assembly, the socket hole is provided in a resin member integrated with an electrical device. The socket hole has an opening, a guide surface and a housing portion. The guide surface has a plurality of segments partitioned by virtual line segments passing through the central axis and respective corner portions of the housing portion when viewed in a direction along the central axis, and at least one of the segments is a first segment. The first segment has a first end portion, a second end portion, and a central portion that protrudes so as to be closer to the opening than the first end portion and the second end portion are.