Rotor Core Fitting Structure for Large Magnetic Pole Skew Offset
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Solution Overview
Problem
Existing rotating electric machine rotors face challenges in achieving a large circumferential offset for magnetic pole skew structures due to limitations in press working, necessitating increased axial length and constraining design flexibility.
Innovation Solution
The rotor core is formed by laminating core sheets with magnetic-pole forming parts having non-overlapping first and second fitting portions, where the second fitting portions are circumferentially offset, allowing for greater freedom in setting formation positions and securing a large offset angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If press working is used to form protrusions and recesses in core sheets, then the core sheets can be joined together, but the circumferential offset between protrusions and recesses is limited
Solution Approach 1:
The core sheet is divided into multiple pressing regions with protrusions and recesses formed in separate pressing operations. This segmentation allows each region to be formed independently with optimal positioning, achieving large circumferential offsets that would be impossible with a single press working operation.
Solution Approach 2:
The solution transitions from attempting to achieve circumferential offset within a single plane to utilizing the axial dimension by forming protrusions and recesses on opposite surfaces of the core sheet. This dimensional approach enables larger effective offsets without being constrained by the limited circumferential adjustment capability of press working tools.
2Manufacturing precision
If the axial length of the rotor core is increased to secure desired circumferential offset, then the skew structure can be achieved, but the device complexity and size increase
Solution Approach 1:
Instead of increasing axial length to achieve circumferential offset, the invention utilizes the radial thickness dimension of the core sheet. By forming protrusions and recesses at different radial positions and combining multiple core sheets, the desired skew structure is achieved without extending the axial length.
Solution Approach 2:
Multiple core sheets with different protrusion-recess configurations are laminated together to create a composite rotor core structure. This composite approach enables the accumulation of circumferential offset across layers while maintaining a compact axial length.
3Manufacturing precision
If the protrusions and recesses are formed by shifting die and punch in circumferential direction, then offset can be achieved, but the design flexibility is constrained
Solution Approach 1:
The core sheet design is segmented into multiple independent pressing regions that can be configured with different circumferential positions. This segmentation provides design flexibility by allowing each region to be optimized independently for specific magnetic pole requirements, rather than being constrained by a single shifted pattern.
Solution Approach 2:
Different regions of the core sheet are given different local characteristics through selectively forming protrusions and recesses in specific pressing regions. This local quality approach enables tailored magnetic pole configurations for different circumferential positions, enhancing design flexibility and adaptability.
Data Source
AI summary
A core for a rotating electric machine is formed by laminating a plurality of core sheet in an axial direction. Each of the core sheets has a first fitting portion and a second fitting portion. One of the first fitting portion and the second fitting portion has a convex shape protruding in the axial direction. The other of the first fitting portion and the second fitting portion has a concave shape recessed in the axial direction. An axially-adjacent pair of the core sheets are joined together by fitting the first fitting portion of one of the pair of the core sheets and the second fitting portion of the other of the pair of the core sheets to each other. The first fitting portion and the second fitting portion provided in a same one of the core sheets are located at positions not overlapping each other in the axial direction.