Pierce Nut Pilot Geometry for Rotational and Pullout Resistance
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Solution Overview
Problem
Manufacturing pierce nuts with recess grooves on the outer circumference surface requires complex molds, leading to high mold breakage rates and increased costs.
Innovation Solution
A pierce nut design featuring a main body, plateau portion, and pilot portion with specific cross-sectional shapes and angles that allow for varying gap lengths and diameters at different rotational positions, enhancing rotational and pullout resistance without complex surface features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a recess groove is provided on the outer circumference surface of the pilot portion to improve pullout resistance and rotational resistance, then the attachment security is improved, but the mold complexity increases and manufacturing costs rise
Solution Approach 1:
The pilot portion is designed with an asymmetric cross-sectional shape where the outer circumference line has different lengths at different positions along the extending direction. Specifically, the outer circumference line length is longer on the first intersection plane closer to the distal end surface and shorter on planes closer to the terrace surface. This asymmetric geometry creates varying gap lengths between the pilot portion and plate material at different rotational positions, generating both rotational and pullout resistance without requiring complex surface features or recess grooves.
Solution Approach 2:
The invention changes the geometric parameters of the pilot portion by defining its cross-sectional shape through specific corner configurations (n corners on one intersection plane, m corners on another intersection plane where m > n). This parameter variation creates the desired asymmetric profile that provides attachment security while maintaining manufacturing simplicity.
2Stability of the object's composition
If a recess groove is provided on the outer circumference surface to enhance rotational resistance, then the rotational stability is improved, but the manufacturing precision requirements increase due to complex mold preparation
Solution Approach 1:
The asymmetric cross-sectional shape of the pilot portion with varying outer circumference line lengths creates different gap lengths at different rotational positions. This geometric asymmetry inherently provides rotational stability by creating resistance to rotation without requiring precisely formed recess grooves, thereby reducing mold preparation precision requirements.
3Ease of manufacture
If a simple shape is adopted for the pierce nut to reduce manufacturing costs, then the ease of manufacture is improved, but the pullout resistance and rotational resistance decrease
Solution Approach 1:
The invention achieves both manufacturing simplicity and pullout resistance by using an asymmetric pilot portion shape that can be formed with relatively simple molding processes. The asymmetric geometry itself, rather than complex surface features, provides the necessary attachment security through varying gap lengths that create resistance to both pulling and rotation.
Solution Approach 2:
By changing the cross-sectional parameters of the pilot portion (different corner configurations at different heights), the invention achieves both ease of manufacture and improved pullout resistance. The parameter variation creates the functional asymmetry needed for attachment security while maintaining manufacturing simplicity.
4Device complexity
If a simple shape is adopted for the pierce nut to reduce mold complexity, then the manufacturing cost is reduced, but the rotational resistance decreases
Solution Approach 1:
The asymmetric cross-sectional shape of the pilot portion with varying outer circumference line lengths creates different gap lengths at different rotational positions. This geometric asymmetry inherently provides rotational resistance by creating unequal clearance zones that resist rotation, all while maintaining a relatively simple overall shape that does not require complex molding operations.
Data Source
AI summary
A pierce nut comprising: a main body; a plateau portion that is provided around a center of a flat surface of the main body and has a thin-plate shape; and a pilot portion that protrudes in an extending direction from around a center of a terrace surface of the plateau portion, wherein the terrace surface of the plateau portion is formed to be raised from the flat surface, and an outer circumference surface of the pilot portion and the terrace surface of the plateau portion are connected through a neck portion between the plateau portion and the pilot portion such that a gap is formed around the neck portion, and on a first intersection plane intersecting the extending direction, the pilot portion has a first cross-sectional shape with n corners (where n is a natural number equal to or larger than 4).