Pierce Nut Geometry for Pullout Resistance Without Complex Molds
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Solution Overview
Problem
Manufacturing pierce nuts with recess grooves on the outer circumference surface requires complex molds, leading to increased mold breakage and higher production costs.
Innovation Solution
A pierce nut design featuring a main body, plateau portion, and pilot portion with specific cross-sectional shapes and varying gap lengths due to non-symmetrical intersections, allowing secure attachment to a plate material without complex surface shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a recess groove is provided on the outer circumference surface of the pilot portion, then pullout resistance and rotational resistance are improved, but manufacturing complexity and mold breakage frequency increase
Solution Approach 1:
The patent applies asymmetry by making the cross-sectional shape of the pilot portion differ from that of the plateau portion. Specifically, the pilot portion has a first cross-sectional shape with n corners while the plateau portion has a second cross-sectional shape with m corners (where n ≠ m). This asymmetric configuration creates variable gap lengths around the neck portion without requiring complex recess grooves on the outer circumference surface, thus improving pullout resistance while maintaining simple mold structures.
Solution Approach 2:
The patent transitions from modifying the outer circumference surface (2D surface feature) to modifying the cross-sectional shapes in different dimensional planes. By changing the cross-sectional shapes of the pilot and plateau portions and creating a 3D variable gap structure around the neck portion, the invention achieves enhanced pullout resistance through volumetric geometry rather than surface features, simplifying mold requirements.
2Strength
If a recess groove is provided on the outer circumference surface of the pilot portion, then rotational resistance is improved, but manufacturing complexity and mold breakage frequency increase
Solution Approach 1:
The asymmetric cross-sectional shapes of the pilot portion (n corners) and plateau portion (m corners, where n ≠ m) create an inherently asymmetric gap distribution around the neck portion. This asymmetry provides effective rotational resistance by creating uneven engagement with the plate material, eliminating the need for complex symmetric recess grooves and reducing overall shape complexity.
3Ease of manufacture
If a simple shape is adopted for the pierce nut, then manufacturing cost decreases, but attachment security may be compromised
Solution Approach 1:
The asymmetric cross-sectional configuration provides enhanced attachment security through variable gap lengths without increasing manufacturing complexity. The different corner counts (n and m) create an optimized engagement pattern with the plate material that improves both pullout and rotational resistance, achieving high reliability with simple, cost-effective molding.
Data Source
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AI summary
A pierce nut includes a main body, a plateau portion, and a pilot portion. The plateau portion is provided around the center of a flat surface of the main body and has a thin-plate shape. The pilot portion protrudes in an extending direction, around the center of a terrace surface of the plateau portion. The terrace surface of the plateau portion is formed to be raised from the flat surface. A gap (16, 116, 216) is formed around a neck portion (15, 115, 215) between the plateau portion and the pilot portion, due to connection between an outer circumference surface (32, 132) of the pilot portion and the terrace surface of the plateau portion through the neck portion (15, 115, 215). On a first intersection plane (PL11, PL21) intersecting the extending direction, the pilot portion has a first cross-sectional shape with n corners, n being a natural number that is equal to or larger than 4.