Ground Spring for Cable Shield EMI Leakage
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Solution Overview
Problem
Existing cable assemblies experience inadequate electromagnetic interference (EMI) shielding due to leakage above certain signal speeds, often damaging the cable braid and causing it to loosen, leading to insufficient shielding.
Innovation Solution
A ground spring is positioned between the cable bundle and the cable shield, with spring members that engage the inner surface of the cable shield to bias it radially outward, ensuring electrical connection to a conductive backshell, thereby enhancing EMI shielding without damaging the cable braid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the cable braid is dressed or flared over a ferrule or support ring, then the cable assembly can be assembled, but the cable braid becomes damaged and loosened leading to insufficient shielding and EMI leakage
Solution Approach 1:
The ground spring acts as an intermediary component between the cable braid and the ferrule/support ring. Instead of directly dressing or flaring the cable braid over rigid structures, the ground spring provides a compliant interface that maintains electrical connection without damaging the braid structure, thus preserving shielding integrity while enabling assembly
Solution Approach 2:
The ground spring changes the mechanical parameters of the connection interface by providing a flexible, spring-loaded contact instead of a rigid constraint. This allows the cable braid to maintain its braided structure while achieving reliable electrical connection to the backshell, preventing EMI leakage
2Reliability
If the cable shield connection is made rigid to ensure electrical connection, then electrical connectivity is achieved, but the cable braid is damaged and shielding becomes insufficient
Solution Approach 1:
The ground spring introduces dynamic compliance to the electrical connection. The spring members can deflect and accommodate movements or variations in the cable braid position while maintaining continuous electrical contact. This dynamic connection ensures reliable connectivity without imposing rigid constraints that would damage the braid structure
3Productivity
If signal speed is increased to improve data transmission, then productivity increases, but EMI leakage occurs above certain frequencies compromising signal integrity
Solution Approach 1:
The ground spring converts the potential harm of cable braid damage into a benefit by providing a separate, compliant connection mechanism. This allows the cable assembly to support high-speed signals with proper shielding, as the ground spring maintains intimate electrical contact between the shield and backshell without compromising the braid structure that would otherwise be damaged by rigid assembly methods
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 ground spring effectively reduces EMI emissions by ensuring a secure and consistent electrical connection between the cable shield and the backshell, maintaining shielding integrity even at high signal speeds without damaging the cable braid.
Implementation Method 1
The ground spring includes spring members engaging the inner surface of the cable shield and biasing the cable shield radially outward. The spring members are compressed inward by the cable shield and engage the inner surface of the cable shield. The spring members bias the cable shield radially outward and force the outer surface of the cable shield outward to electrically connect the cable shield to a conductive element.
Data Source
AI summary
An electrical connector assembly includes a cable assembly having a cable bundle of cables and a conductive cable shield surrounding and providing electrical shielding for the cable bundle. The cable assembly includes an electrical connector a housing holding contacts and a conductive backshell having a cavity that receives the electrical connector to provide electrical shielding for the electrical connector. The backshell has a cable channel at a rear of the backshell that receives the cable. A ground spring is coupled to the cable and positioned between the cable bundle and the cable shield. The ground spring includes spring members engaging the inner surface of the cable shield and biasing the cable shield radially outward. The ground spring is received in the cable channel and forces the outer surface of the cable shield outward against the backshell to electrically connect the cable shield to the backshell.