Overmolded Insulating Envelope for Automotive Alternator Terminal
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Solution Overview
Problem
Existing solutions for connecting a motor vehicle's battery cable to a rotating electrical machine, such as an alternator, face issues with mechanical stability and electrical insulation, particularly due to thermal expansion and vibration-induced degradation, which can lead to short-circuits and damage.
Innovation Solution
A connection terminal with a core and an overmolded insulating envelope that includes high-thermal and mechanical performance inserts, along with a conductive male plug and indexing skirt, ensuring stable and isolated attachment to the heat sink and reducing the risk of accidental contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional metal components (metal thimble, metal male fixing lug, copper washer) are used for connection, then electrical conductivity is ensured, but electrical insulation from ground becomes difficult to guarantee
Solution Approach 1:
An insulating envelope made of electrically insulating material is introduced as an intermediary component that completely encases the metal core and all metal connection components. This envelope acts as a mediator between the conductive metal parts and the ground, providing reliable electrical insulation while maintaining simple connection structures.
Solution Approach 2:
The insulating envelope functions as a protective shell that completely surrounds the metal core, insulating washers, and clamping nut. This shell structure provides comprehensive electrical insulation from ground while allowing the internal metal components to maintain their mechanical and electrical functions.
2Strength
If metal components are used for mechanical connection, then mechanical strength is achieved, but thermal expansion causes loosening over time
Solution Approach 1:
The connection assembly combines metal components (core, washers, nut) with non-metallic insulating material (envelope). The metal parts provide mechanical strength and electrical conductivity, while the insulating envelope provides thermal isolation and structural stability, compensating for thermal expansion effects.
Solution Approach 2:
The insulating envelope acts as a protective shell that constrains and stabilizes the metal connection components. This shell structure prevents loosening by providing a stable framework that accommodates thermal expansion while maintaining mechanical connection integrity over time.
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 solution provides a stable, electrically isolated connection with reduced risk of short-circuits, maintaining mechanical and thermal stability over time, and facilitating easy assembly and maintenance.
Implementation Method 1
an envelope produced by overmoulding an electrically insulating material on the core, the insulating envelope entirely encasing all of the female fastening means and electrically conductive connection means
Implementation Method 2
the existing solutions for locking the 'metal lug/tightening nut' assembly on the rotating electrical machine in rotation are not entirely satisfactory and tend to deteriorate over time, for example under the effect thermal expansion of the various materials
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The terminal has a sleeve formed by overmolding an electrically insulated material on a core. The sleeve entirely encloses a female fixation unit and electrically conductive connection elements such as conductive washer (9) and spacer (10), except a transversal end face at a socket terminal of a rotary electric machine and an attachment at a female metal lug attached at an end of an electric cable. The unit has two inserts (8) formed from an insulating material having high thermal and mechanical characteristics. The inserts are introduced in an orifice (6) at respective faces of a ring (5). An independent claim is also included for a method for fabricating a connection terminal.