Stacked Permanent Magnet Rotor Assembly for Low-NVH Manufacturing
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Solution Overview
Problem
The high overall process difficulty of the rotor in permanent magnet motors leads to low production efficiency, which is a challenge in achieving optimal NVH performance.
Innovation Solution
The rotor is designed with at least two coaxially stacked rotor assemblies, each with evenly arranged permanent magnet slot groups, and bosses in the laminations to facilitate an axial combination structure, reducing magnetic field offset and torque, thereby simplifying the production process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If adjacent rotor magnetic poles are slightly staggered with different included angles to optimize NVH performance, then electromagnetic noise is reduced, but the overall process difficulty of the rotor increases and production efficiency decreases
Solution Approach 1:
The rotor is divided into a first rotor assembly and a second rotor assembly that can be manufactured separately and then assembled together. Each assembly contains rotor laminations with permanent magnet slots, and the assemblies are connected through boss fitting. This segmentation allows each assembly to be produced independently using standardized processes, avoiding the need for complex single-piece manufacturing while achieving the staggered magnetic pole configuration for optimized NVH performance.
Solution Approach 2:
The first rotor assembly and second rotor assembly are combined through axial stacking and boss fitting to form the complete rotor. The magnetic fields of the two assemblies are offset relative to each other, achieving the desired NVH optimization. This merging approach maintains production efficiency by using modular components that can be assembled through simple fitting operations rather than complex integrated manufacturing.
2Reliability
If a complex rotor structure with staggered magnetic poles is used to reduce torque ripple, then NVH performance is optimized, but the manufacturing process becomes more difficult
Solution Approach 1:
The rotor is segmented into two separate assemblies that can be manufactured using standard processes. Each assembly contains rotor laminations with permanent magnet slots arranged in specific patterns. The segmentation transforms a complex single-piece manufacturing challenge into two simpler, standardized manufacturing processes followed by a straightforward assembly operation.
Solution Approach 2:
The boss structure serves as an intermediary element that facilitates the connection between the first and second rotor assemblies. The bosses protrude from the laminations and fit into corresponding slots, providing a simple mechanical interface that enables assembly without complex fastening or joining processes. This intermediary structure simplifies the overall manufacturing process while maintaining the desired magnetic pole configuration.
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 design optimizes NVH performance, reduces production complexity, and enhances the reliability and efficiency of the permanent magnet motor, facilitating mass production.
Implementation Method 1
a first permanent magnet is disposed in each first permanent magnet slot. a second permanent magnet is disposed in each second permanent magnet slot
Implementation Method 2
A magnetic field offset between the first rotor assembly and the second rotor assembly can be implemented by using the first bosses in the first rotor laminations and the second bosses in the second rotor laminations, so that a torque between the first rotor assembly and the second rotor assembly is reduced
Data Source
AI summary
This application describes examples of a rotor, a permanent magnet motor and a powertrain. In one example, in a first rotor assembly of a rotor structure, each first rotor lamination is provided with a plurality of first permanent magnet slot groups, and a first boss is disposed at one end that is of each first permanent magnet slot of the first permanent magnet slot group and that is close to an outer edge of the first rotor lamination. In a second rotor assembly of the rotor structure, each second rotor lamination is provided with a plurality of second permanent magnet slot groups, and a second boss is disposed at one end that is of each second permanent magnet slot of the second permanent magnet slot group and that is close to an outer edge of the second rotor lamination.