Electric Machine Heat-Sensitive Joint for High-Temperature Protection
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Solution Overview
Problem
Existing electric machines lack effective high-temperature protection mechanisms that are efficient, cost-effective, and capable of withstanding prolonged exposure to high temperatures, especially in automotive applications, where overheating can lead to malfunction, damage, or safety hazards.
Innovation Solution
An electric machine design featuring a heat-dissipative structure with conductive tracks and heat-conductive filler, combined with a heat-sensitive joint system using a brazing alloy, which breaks at a predetermined temperature to disconnect power supply, and an elastic element to ensure efficient heat dissipation and power cutoff.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a customary thermal fuse is fitted along a power supply circuit to cut off power in the event of overheating, then high-temperature protection is provided, but the thermal fuse cannot be oven brazed with other electrical components and must be installed separately, increasing assembly time and costs
Solution Approach 1:
The patent combines the thermal fuse with the printed circuit board assembly by making the thermal fuse body integrally form the printed circuit board or being brazed thereto. This merging allows the thermal fuse to be oven brazed together with other electrical components in a single process, eliminating separate installation steps and reducing assembly time while maintaining reliable high-temperature protection.
2Reliability
If a customary thermal fuse is fitted to provide high-temperature protection, then safety is improved, but the thermal fuse contains fluxes that cause gradual deterioration when subjected to constantly high temperatures, making it unsuitable for high-temperature environments
Solution Approach 1:
The patent changes the material parameters of the thermal fuse by using a fusible alloy with a melting point between 100°C and 200°C and specifically avoiding fluxes that deteriorate at high temperatures. The thermal fuse body is designed to withstand constant high-temperature exposure without gradual deterioration, while the fusible element remains stable until the protection threshold is reached, enabling long service life in high-temperature environments like automotive engine compartments.
3Reliability
If conventional thermal fuses are used for high-temperature protection, then power cutoff is achieved, but the structure cannot be integrated with other machine components, limiting efficiency in terms of cost, weight and overall functioning
Solution Approach 1:
The patent merges the thermal fuse with the printed circuit board and other electrical components by making the thermal fuse body integrally form the printed circuit board or being brazed thereto. This integration reduces the number of separate components, simplifies the overall structure, reduces weight, and improves cost-efficiency while maintaining reliable high-temperature protection functionality.
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 reliable high-temperature protection, reduces production costs, and supports wider operating current and temperature ranges, ensuring safety and efficiency in high-temperature environments without the limitations of traditional thermal fuses.
Implementation Method 1
heat-conductive filler
Implementation Method 2
brazing alloy, which breaks at a predetermined temperature
Implementation Method 3
heat-dissipative structure
Data Source
AI summary
An electric machine includes a plurality of conductive tracks defining an electric power circuit, to provide current for electronic power components, a printed circuit board which mounts the conductive tracks, an enclosure which defines a housing for the printed circuit board and has a dissipative wall, a heat-conductive filler interposed between the printed circuit board and the enclosure, an elastic device acting on the printed circuit board to press it against the dissipative wall, a conductive element held in position by at least one heat-sensitive joint and disposed to connect a first track and a second track to close the electric power circuit. The elastic device includes an elastic element pressed against the conductive element to apply a force on the heat-sensitive joint and the heat-sensitive joint is configured to break if subjected to a temperature higher than a predetermined threshold temperature to open the electric power circuit.