Snap Flange Relief Geometry for Low-Stress Secure Assembly

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Solution Overview

Problem

Snap-type assemblies face challenges in providing sufficient overlap between tab and pocket for secure connection without causing plastic deformation, fracture, or damage, particularly at the neck of the snapping flange due to high stress concentrations.

Innovation Solution

A multi-component snap assembly with a snap flange featuring a contact face with a relief, providing at least three distinct contact points during insertion, and a retention pocket on a more rigid component, allowing for a predominantly radial inward engagement to reduce stress and ensure secure attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If sufficient overlap is provided between the tab and pocket to ensure secure attachment, then the attachment strength is improved, but the stress concentration at the neck of the snapping flange increases causing plastic deformation, fracture, or damage

Engineering Contradiction:

Improveattachment strengthVSAvoidstress concentration

Core Design Contradiction:

StrengthVSStress or pressure

Solution Approach 1:

The contact face of the snap nose is segmented into multiple distinct contact points (at least three) arranged along the insertion path. This segmentation distributes the attachment force across multiple locations rather than concentrating it at a single point, thereby reducing stress concentration at the neck while maintaining sufficient overall overlap for secure attachment

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The snap nose features a relief or reduced cross-section region that locally modifies the geometry to create an asymmetrical profile. This local quality change creates multiple contact points with the retention pocket wall during insertion, distributing the stress along the insertion path rather than concentrating it at the neck, thus preventing plastic deformation and fracture

Inventive Principle:

Principle #3Local quality

2Productivity

If the second component is pressed radially inward during assembly, then the assembly speed is improved, but the stress on the snap flange increases

Engineering Contradiction:

Improveassembly speedVSAvoidstress on snap flange

Core Design Contradiction:

ProductivityVSStress or pressure

Solution Approach 1:

The snap nose geometry is pre-configured with an asymmetrical profile and relief region that guides the second component along a controlled insertion path. This preliminary geometric arrangement ensures that as the component is pressed radially inward, the contact points engage progressively along the predetermined path, distributing the stress before final engagement occurs

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The insertion process incorporates both radial and axial movement components rather than purely radial pressing. The snap nose geometry guides the second component to move along a three-dimensional path that combines radial inward motion with axial displacement, distributing the stress over a longer effective path and reducing peak stress on the snap flange while maintaining assembly speed

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS12104646B2Snap feature assembly and method

Publication Date: 2024.10.01 SCHAEFFLER TECHNOLOGIES AG & CO KG

AI summary

A multi-component snap assembly is disclosed herein in which a snap flange has a snap nose with a contact face including a relief. The relief is configured to prevent undesirably high stress in the snap flange during assembly with another component that includes a retention pocket. A method of attaching or connecting two components with each other using a snap flange with a relief is also disclosed herein.