Traction Motor Interface Sealing for Thermal Movement and Isolation
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Solution Overview
Problem
Existing interface arrangements for electric traction systems in vehicles face challenges in maintaining reliable electrical insulation and fluidic sealing across a wide temperature range while accommodating thermal expansion and mechanical movement between the stator housing and protective housing of the electric traction motor and power electronics.
Innovation Solution
An interface arrangement featuring a sealing element made of rubber, elastomer, or silicone, with contact plates of copper or aluminum alloy, and optionally a ferritic metal ring, that securely connects and insulates the stator housing and protective housing, allowing for thermal movement and electrical conductivity, while using vulcanization for adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple sealing elements made of different materials are used to fluidically separate the power electronics from the motor interior, then the sealing reliability is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent combines multiple sealing functions into a single sealing element made of thermoplastic elastomer. This single element simultaneously provides fluidic sealing, electrical insulation, and mechanical flexibility to accommodate thermal expansion, replacing what would traditionally require multiple separate sealing components made of different materials.
Solution Approach 2:
The patent employs thermoplastic elastomer as a composite material that integrates the properties of both thermoplastics (processability, electrical insulation) and elastomers (flexibility, sealing capability). This composite material allows the single sealing element to maintain reliable sealing and insulation across the wide temperature range of -40°C to 180°C while accommodating dimensional changes.
2Reliability
If the interface arrangement compensates for thermal expansion of housing and contact plate, then the reliability across temperature range is improved, but the design complexity increases
Solution Approach 1:
The patent utilizes the temperature-dependent properties of thermoplastic elastomer, which changes its physical parameters (flexibility, elasticity) with temperature. This allows the sealing element to automatically adapt to thermal expansion and contraction of the housing and contact plate without requiring additional compensation mechanisms.
Solution Approach 2:
The sealing element itself provides the thermal compensation function through its inherent elastomeric properties. The material naturally expands and contracts with temperature changes, maintaining sealing contact and electrical insulation without requiring external compensation devices or complex design interventions.
3Reliability
If the contact plate reaches through the stator housing and protective housing, then the electrical connection is improved, but the risk of fluid leakage and contamination increases
Solution Approach 1:
The patent uses a flexible thermoplastic elastomer sealing element that forms a sealed enclosure around the contact plate as it passes through the housing. This flexible sealing structure allows the contact plate to move electrically while preventing oil and coolant from penetrating through the passage, thus eliminating the harmful fluid leakage risk.
Solution Approach 2:
The sealing element acts as an intermediary between the electrical connection requirement (contact plate passing through) and the sealing requirement (preventing fluid leakage). It provides a transition zone that allows electrical conductivity while blocking fluid passage, resolving the contradiction between these two opposing requirements.
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 interface arrangement ensures long-lasting electrical insulation and fluidic separation, maintaining functionality across extreme temperatures and mechanical stress, thereby extending the system's lifetime and ensuring environmental protection.
Implementation Method 1
The sealing element must electrically isolate an electric interface of the electric motor, comprising at least one contact plate, from a stator housing of the electric motor and a protective housing of the electronic module
Implementation Method 2
the interface arrangement has at least one sealing element, which fluidically separates the power electronics from the interior of the electric traction motor in order to protect the power electronics and prevents a leakage of oil from the stator housing
Implementation Method 3
the interface arrangement must compensate for thermally produced changes in dimension of the stator housing, the protective housing and/or the contact plate
Implementation Method 4
using vulcanization for adhesion
Data Source
AI summary
An interface arrangement for an electric traction system of a vehicle comprises a stator housing of an electric traction motor of the electric traction system, a protective housing of a power electronics of the electric traction system and at least one contact plate of an electric interface of the electric traction motor reaching through the stator housing and the protective housing and a sealing element having the at least one contact plate reaching through the sealing element. An electric traction system for a vehicle, and a method for making a sealing element for an interface arrangement of an electric traction system of a vehicle are also provided.