Snap Locking Features Spatial Gap Elimination

Solution Overview

Problem

Snap locking features in electrical connection systems result in spatial gaps due to 'over travel' during assembly, leading to increased forces from vibration and thermal cycling, reducing product life and increasing warranty costs.

Innovation Solution

A method using ultrasonic vibrational energy to form a protrusion on one component, which contacts the other component, eliminating the spatial gap between mating surfaces by deforming a portion of the first part to create a dimple and corresponding protrusion, ensuring direct contact and minimizing relative motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If snap locking features are assembled with over travel distance to accommodate resilient member flexing, then the locking features can engage properly, but a spatial gap forms between mating surfaces that allows relative motion under vibration and thermal cycling

Engineering Contradiction:

Improvelocking feature engagementVSAvoidrelative motion from vibration and thermal cycling

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The protrusion is formed on the resilient member before assembly, pre-positioned to contact the rigid member and eliminate the gap that would normally form due to over travel. This preliminary geometric modification ensures that when assembly occurs, the gap is already compensated for, preventing relative motion under vibration and thermal cycling while maintaining proper locking engagement.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A localized protrusion is added to a specific portion of the resilient member (the snap locking feature) rather than modifying the entire component. This localized geometric change allows the resilient member to maintain its overall flexibility and locking function while creating a specific contact point that eliminates the spatial gap between mating surfaces.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If over travel distance is used in snap locking assembly, then resilient members can flex and engage, but spatial gaps form that cause force multiplication factors of two to three times greater than expected

Engineering Contradiction:

Improveresilient member flexing and engagementVSAvoidforces during vibration testing

Core Design Contradiction:

Ease of operationVSForce

Solution Approach 1:

The protrusion is formed on the resilient member before assembly, pre-positioned to contact the rigid member and eliminate the gap that would normally form due to over travel. This preliminary geometric modification ensures that when assembly occurs, the gap is already compensated for, preventing relative motion under vibration and thermal cycling while maintaining proper locking engagement.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A localized protrusion is added to a specific portion of the resilient member (the snap locking feature) rather than modifying the entire component. This localized geometric change allows the resilient member to maintain its overall flexibility and locking function while creating a specific contact point that eliminates the spatial gap between mating surfaces.

Inventive Principle:

Principle #3Local quality

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 method reduces forces experienced during vibration, enhances assembly reliability, and aligns vibration performance with expected results, making the connection more resistant to inadvertent disassembly and reducing warranty costs.

Implementation Method 1

The protrusion may be formed by applying ultrasonic vibrational energy to the first part using a generally cylindrical probe

Methodology Applied

Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Data Source

PatentUS10082168B2Method for reducing spatial gaps in snap locking features

Publication Date: 2018.09.25 APTIV TECHNOLOGIES AG

AI summary

A method of closing a spatial gap between a first mating surface of a first snap locking feature defined by a first part and a second mating surface of a second snap locking feature defined by a second part. This method includes the steps of attaching the first and second parts to one another by sliding the first and second snap locking features over one another until the first mating surface is proximate the second mating surface and deforming a portion of the first part to fabricate a protrusion that contacts the second part and urges the second part in a direction effective to place the first and second mating surfaces into direct contact with one another.