Capped Wheel Fastener with Deflected Projections for Weight Reduction

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Solution Overview

Problem

Automotive wheel nuts are prone to corrosion due to their exposure to wet and salty environments, affecting their aesthetic appearance, and there is a need to reduce their weight while maintaining durability and aesthetics to improve energy efficiency.

Innovation Solution

A fastener design featuring a threaded body with a top portion and a bottom portion forming a horizontal shelf, where projections on the shelf extend radially outward to axially retain a cap with a double wall section, eliminating the need for a radial flange, thus reducing weight and simplifying assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a radial flange is used to secure the cap, then the cap retention is improved, but the weight and material cost increase

Engineering Contradiction:
Improvecap retentionVSAvoidwheel nut weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent removes the radial flange from the fastener body, extracting the unnecessary component that added weight. Instead, projections on the shelf engage with the cap wall to provide cap retention, achieving the same function with less material.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent concentrates the retention function at specific locations (projections on the shelf engaging with the cap wall) rather than using a comprehensive radial flange structure. This localized approach reduces material while maintaining effectiveness.

Inventive Principle:
Principle #3Local quality

2Reliability

If a complex assembly process is used to secure the cap, then the cap retention is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improvecap retentionVSAvoidassembly process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The projections on the shelf automatically engage with the cap wall during assembly through elastic deformation, creating a self-retaining mechanism that eliminates complex assembly steps while ensuring reliable cap retention.

Inventive Principle:
Principle #25Self-service

3Strength

If more material is used to reinforce the fastener body, then the strength is improved, but the weight increases

Engineering Contradiction:
Improvefastener body strengthVSAvoidwheel nut weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent segments the reinforcement function into discrete projections on the shelf rather than adding material throughout the entire fastener body. This targeted reinforcement provides necessary strength while minimizing weight increase.

Inventive Principle:
Principle #1Segmentation

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 reduces the weight of wheel nuts, improves handling performance, and maintains durability and aesthetics by using an interference fit and projections to secure the cap, which also simplifies the assembly process and reduces material costs.

Implementation Method 1

the plurality of projections are deflecting the plurality of projections radially outward beyond the circular cross-section of the bottom portion of the fastener body

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3242046B1Capped wheel fastener and method of assembly
Publication Date: 2021.12.29 MACLEAN FOGG CO
  • EP3242046B1 patent drawingFigure 1A~1B
  • EP3242046B1 patent drawingFigure 2A~2C
  • EP3242046B1 patent drawingFigure 3A~3C

AI summary

A capped fastener is provided with deflected projections on the nut body for securing a cap on the nut body. The deflected projections fit within a double walled edge of the cap. The projections are deflected through a simple method during the assembly process.