Sintered Stator-Yoke Sheet Assembly for Low Magnetic Leakage
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Solution Overview
Problem
Existing manufacturing methods for stator-yoke assemblies in electric machines are complex and lack a simple, reliable method to produce star-yoke assemblies with low magnetic leakage and high stiffness.
Innovation Solution
A manufacturing process involving the production of layers from a paste of soft magnetic powder particles and a binder, followed by drying, sintering, and joining these layers to form small stacks, which are then contoured and separated into star and yoke parts, using adhesive lacquer for bonding and material removal to achieve the desired shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sheet metal manufacturing methods are used, then manufacturing complexity is reduced, but magnetic leakage increases and stiffness decreases
Solution Approach 1:
The patent uses composite material technology by combining soft magnetic powder particles with a binder to create sintered sheets. This composite structure achieves low magnetic leakage while maintaining manufacturing simplicity, as the powder metallurgy process allows for direct formation of complex geometries without conventional sheet metal working
Solution Approach 2:
The patent changes the physical and chemical parameters of the magnetic material by controlling the sintering process. By adjusting sintering temperature, time, and atmosphere, the magnetic properties and mechanical strength are optimized to achieve low magnetic leakage while keeping the manufacturing process simple
2Strength
If conventional sheet metal components are used, then manufacturing is simpler, but stiffness is insufficient for the joining process
Solution Approach 1:
The sintered composite material provides superior stiffness compared to conventional sheet metal. The interlocking powder structure and binder system create a rigid component that can withstand the joining process forces while maintaining manufacturing simplicity through the sintering process
Solution Approach 2:
The stator-yoke assembly is segmented into multiple thin sintered sheets that are stacked and joined together. This segmentation allows each individual sheet to be manufactured simply through sintering, while the stacked assembly achieves the required overall stiffness for the joining process
3Reliability
If thin sintered sheets are stacked to form the stator-yoke assembly, then magnetic leakage is reduced and stiffness is increased, but manufacturing process becomes more complex
Solution Approach 1:
The stator-yoke assembly is divided into multiple thin sintered sheets that are stacked in sequence. Each sheet can be manufactured independently through the sintering process, and the stacking arrangement reduces magnetic leakage paths while the cumulative structure provides the necessary stiffness
Solution Approach 2:
A binder is used as an intermediary material between the soft magnetic powder particles. This binder holds the particles together during sintering and in the final assembled structure, enabling the stacking of multiple sheets while maintaining structural integrity and reducing manufacturing complexity
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 method simplifies the manufacturing process, ensures high stiffness and low magnetic stray fields, and facilitates easy handling and assembly of stator-yoke assemblies.
Implementation Method 1
the layers are dried and then sintered so that the layers each form a sheet with a layer thickness
Implementation Method 2
In this furnace (or another furnace), any remaining binder is removed before sintering, primarily by evaporation
Implementation Method 3
the adhesive lacquer is dried, the sheets coated with the adhesive lacquer are stacked on top of each other and pressed together, and the adhesive lacquer is activated, for example by heating
Data Source
Figure 1~3
Figure 4~5
Figure 6~7
AI summary
To manufacture a stator-yoke assembly of an electric machine, star parts (16) are stacked in a stacking direction (z) to form a star assembly (19) with an inner ring and teeth projecting radially outwards from the inner ring, and yoke parts (17) are stacked in the stacking direction (z) to form a yoke assembly (22). After the radially outwards projecting teeth are wound with a stator winding (21), the star assembly (19) and the yoke assembly (22) are joined together so that the yoke assembly (22) radially surrounds the star assembly (19). To manufacture the star parts (16) and the yoke parts (17), layers (2) are produced from a paste (1) consisting of soft magnetic powder particles (3) and a binder (4). The layers (2) are dried and then sintered, so that the layers (2) each form a sheet (7, 7', 7") with a layer thickness (d1).The sheets (7, 7', 7") are joined to form small stacks (8) with a respective stack thickness (d2), each small stack (8) comprising several stacked sheets (7, 7', 7") in the stacking direction (z). The small stacks (8) are contoured by material removal and separated into the star parts (16) and the yoke parts (17).