Multi-Phase Magnetic Component Selective Nitriding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic materials used in electric machines face a tradeoff between efficient magnetic utilization and mechanical load-bearing capability, with existing methods struggling to control saturation magnetization effectively, particularly in hybrid and electric vehicle traction applications where power density and efficiency are critical.
Innovation Solution
A magnetic component with regions of varying nitrogen content, formed through selective nitriding, allowing for precise control of saturation magnetization by creating magnetic, partially-magnetic, and non-magnetic regions, thereby optimizing magnetic flux distribution and mechanical integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional ferrous-based magnetic steels are used to increase power density, then magnetic utilization is improved, but mechanical load-bearing capability deteriorates
Solution Approach 1:
The patent applies local quality by creating regions with different nitrogen contents within the magnetic component. High nitrogen content regions (0.1-0.4 wt%) provide enhanced mechanical strength and load-bearing capability, while low nitrogen content regions (<0.1 wt%) maintain high magnetic saturation and efficient magnetic flux coupling. This spatial variation in nitrogen distribution allows the component to simultaneously achieve both improved mechanical properties and magnetic performance in different locations.
Solution Approach 2:
The patent creates a composite microstructure by combining regions with different nitrogen contents, effectively producing a multi-phase material system. The high nitrogen regions act as mechanically strengthened zones, while low nitrogen regions serve as magnetically optimized zones. This composite approach allows the magnetic component to exhibit both high strength and high magnetic utilization, resolving the tradeoff between mechanical load-bearing capability and power density.
2Power
If carbides are added to stabilize austenite regions, then magnetic flux distribution is improved, but coercivity increases and magnetic saturation decreases
Solution Approach 1:
The patent changes the chemical composition parameter by controlling nitrogen content in different regions instead of relying on carbide formation. By introducing nitrogen at controlled concentrations (0.1-0.4 wt% in high nitrogen regions, <0.1 wt% in low nitrogen regions), the patent stabilizes austenite phases and controls magnetic properties without the harmful effects of carbide precipitation. This parameter change approach achieves desired magnetic flux distribution while maintaining low coercivity and high magnetic saturation.
3Power
If machine size is increased to improve power density, then magnetic utilization increases, but mass and cost increase
Solution Approach 1:
The patent applies local quality by creating spatially varying nitrogen content regions that optimize both magnetic and mechanical properties locally. This allows the magnetic component to achieve high power density without increasing overall machine size, as the enhanced local properties enable more efficient use of the existing component volume. The high nitrogen regions provide mechanical strength to support higher loads, while low nitrogen regions maximize magnetic flux coupling efficiency.
4Power
If rotor speed is increased to improve power density, then efficiency increases, but constant power speed range is reduced
Solution Approach 1:
The patent creates a composite microstructure with regions of different nitrogen contents that provides both high-speed performance and extended operational range. The high nitrogen regions maintain mechanical integrity at high rotor speeds, enabling efficient operation at elevated velocities. Simultaneously, the low nitrogen regions maintain optimal magnetic properties across a broader speed range, extending the constant power operating window and improving overall adaptability.
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
This approach enhances power density and efficiency in electric machines by allowing precise control of magnetic flux distribution and mechanical integrity, addressing the tradeoff between magnetic utilization and mechanical load-bearing capabilities.
Implementation Method 1
formed through selective nitriding, allowing for precise control of saturation magnetization by creating magnetic, partially-magnetic, and non-magnetic regions
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A magnetic component (10) including first and second regions (20, 30), and a method of varying the magnetization values in different regions of the magnetic component are disclosed. The first and the second regions are characterized by a nitrogen content that is different from each other. At least one of the first region and the second region is partially-magnetic and has a nitrogen content in a range from about 0.1 weight % to about 0.4 weight % of that region. A concentration of carbon, if present, of both the first and second regions is less than about 0.05 weight% of the respective regions.