Stator Housing Ground Contact for Heat Dissipation and Static Control
Solution Overview
Problem
In automated vehicle transmissions, brushless electric motors experience detachment of electronic assemblies from the stator housing due to vibrations, leading to inadequate heat dissipation and potential static charge buildup, which can affect the operation of surrounding components.
Innovation Solution
A metal stator housing with a contact point integrated as one part, connected via a ground cable to the vehicle bodywork, ensuring effective heat dissipation and preventing static charge buildup, while maintaining a secure and cost-effective assembly process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the electronic assembly is thermally insulated from the stator housing, then heat dissipation from the stator housing is improved, but the electrical contact between the electronic assembly and stator housing becomes insufficient
Solution Approach 1:
The electrical connection is segmented into two independent functions: the screw provides mechanical fastening and electrical contact, while the dedicated ground cable provides the ground connection. This segmentation allows the electrical contact function to be maintained independently from the thermal insulation function.
Solution Approach 2:
A dedicated ground cable acts as an intermediary element between the stator housing and the electronic assembly, providing a reliable ground connection path that is independent of the thermal insulation arrangement. The ground cable ensures electrical contact without compromising thermal insulation.
2Strength
If screws are used to fasten the electronic assembly to the stator housing, then mechanical connection is achieved, but the screw may become detached or loosened due to vibrations
Solution Approach 1:
The design anticipates the loosening problem by providing a redundant ground connection through the ground cable. Even if the screw connection deteriorates over time due to vibrations, the ground connection remains intact, cushioning against the potential failure mode.
3Reliability
If a ground cable is connected to the stator housing, then static charge buildup is prevented, but additional components and assembly steps are required
Solution Approach 1:
The ground cable connection is merged with the existing electrical connection structure. The ground cable is routed through the same mounting area and secured using the same fastening mechanism (screw) as the electronic assembly, combining multiple functions into a single assembly operation.
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 prevents static charge buildup, ensures reliable operation, reduces electromagnetic interference, and eliminates the need for additional insulation, resulting in a safer, more efficient, and cost-effective electric motor design.
Implementation Method 1
a ground cable (also described as a ground line or ground connection) is in electrical contact with the contact point by means of which a static charge build-up on the stator housing is avoided. As a consequence, an electrical charge transfer is rendered possible from the stator housing by way of the ground cable to the bodywork.
Implementation Method 2
during the operation of the electric motor, heat that is produced within the field winding is dissipated to said stator housing
Data Source
AI summary
An electric motor for an adjusting device of a motor vehicle, particularly of a gearbox actuator, has a stator energized by an electronic mechanism and a rotor for powering the motor. The stator is disposed in a metallic stator housing on which a contact point for connecting an earth cable is integrally shaped.