Shielded Connector Contact Cage Reduces RF Leakage and Insertion Force

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Shielded electrical connectors used in automotive applications face challenges in achieving adequate electromagnetic shielding while maintaining low cost and minimizing RF leakage and connector insertion force, due to issues with contact between shield terminals.

Innovation Solution

A shielded electrical connector assembly featuring a contact cage with arcuate contact arms and a slideable attachment to the shield terminal, which compressively contacts the mating terminal's inner wall, reducing RF leakage and insertion force, and utilizing a stainless steel contact cage with folded tabs for secure attachment and minimal openings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lances (cantilevered contacts) are used to provide electrical contact between shield terminals, then electrical contact is improved, but RF leakage increases due to openings in the shield terminals

Engineering Contradiction:

Improveelectrical contactVSAvoidRF leakage

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

A contact cage is introduced as an intermediary component between the shield terminal and mating connector. The contact cage includes multiple contact fingers that make contact with the mating shield terminal, eliminating the need for lances that create openings. This mediator structure provides reliable electrical contact while maintaining shield integrity and preventing RF leakage.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The contact function is segmented from the shield terminal structure itself. Instead of forming lances directly in the shield terminal (which creates openings), the contact function is separated into a distinct contact cage component with multiple individual contact fingers. This segmentation allows the shield terminal to remain intact for RF shielding while the separate contact cage provides the necessary electrical connection.

Inventive Principle:

Principle #1Segmentation

2Reliability

If copper rings are used to provide electrical contact between shield terminals, then electrical contact is improved, but connector insertion force increases to levels that make assembling difficult

Engineering Contradiction:

Improveelectrical contactVSAvoidconnector insertion force

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The contact cage is designed with flexible contact fingers that can dynamically adjust during insertion. The contact fingers are resilient and can deflect to accommodate manufacturing tolerances and mating variations, providing consistent contact force without requiring high insertion force. This dynamic design allows the contacts to engage progressively as the connector is inserted, rather than requiring all contacts to engage simultaneously at high force.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The contact fingers are constructed as flexible, thin-walled elements that can bend and deform elastically. This flexibility allows the contact cage to engage the mating shield terminal with low insertion force while maintaining reliable electrical contact. The thin-walled construction enables the contacts to conform to the mating surface without requiring excessive force, solving the assembly difficulty problem.

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If cold drawn tubular shield terminals are used to meet signal loss and contact resistance specifications, then performance specifications are met, but manufacturing cost increases

Engineering Contradiction:

Improvesignal loss and contact resistanceVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The shield terminal is designed using a cost-effective stamping and forming process rather than expensive cold drawing. The contact cage is made from a relatively inexpensive phosphor bronze or beryllium copper alloy that can be efficiently stamped into shape. This approach replaces the high-cost cold drawn tubular construction with a more economical stamped construction that achieves the same electrical and shielding performance.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The material parameters and geometric parameters of the shield terminal are optimized for the stamping process rather than cold drawing. The terminal is designed with features that are naturally suited to stamping, such as integrated contact fingers and cage structures. This parameter change in the manufacturing approach and design geometry significantly reduces manufacturing cost while maintaining the required electrical contact and shielding properties.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP3787125B1Shielded electrical connector assembly and manufacturing method thereof

Publication Date: 2022.08.03 APTIV TECHNOLOGIES LTD

Figure 1
Figure 2
Figure 3~4

AI summary

A shielded electrical connector assembly (10) is presented herein. The shielded electrical connector assembly (10) includes a shield terminal (32) having an attachment portion (22) configured to be connected to a shield conductor (38) of a coaxial cable (18) and a connection portion (44) configured to be received within a mating shield terminal (20) and a contact cage (46) surrounding a forward segment of the connection portion (44) and slideably attached to the shield terminal (32). The contact cage (46) defines a plurality of arcuate contact arms (48) configured to be in intimate compressive contact with a mating shield terminal inner wall (50) which causes the contact cage (46) to extend rearwardly when the shield terminal (32) is inserted within the mating shield terminal (20). Methods (100, 200) of forming and interconnecting a shielded electrical connector assembly (10) are also presented herein.