Arc Magnet Rotor Design for Compact EV Motors
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Solution Overview
Problem
The existing rotors of rotating electrical machines for electric vehicles face challenges in reducing size while maintaining cost-effectiveness, as the arrangement of arc magnets leads to increased circumferential length and rotor size.
Innovation Solution
A rotor design featuring outer and inner diameter side arc magnets with symmetrical arrangements and shared shapes, where the arc centers are strategically positioned to minimize circumferential length, allowing for the use of the same arc magnets across different portions, thereby reducing manufacturing costs and size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If arc magnets are arranged with arc centers on the d-axis to simplify manufacturing, then manufacturing cost is reduced, but the circumferential length of the magnetic pole portion increases and rotor size increases
Solution Approach 1:
The patent applies asymmetry by positioning the arc centers of inner diameter side arc magnets off the d-axis (at positions other than the arc center of outer diameter side arc magnets). This asymmetric arrangement allows the magnetic pole portion to be more compact in the circumferential direction, reducing the rotor's overall size while still enabling cost-effective manufacturing through standardized arc magnet designs.
Solution Approach 2:
The patent transitions from a single-layer arrangement to a multi-layer configuration, placing arc magnets at different radial positions (outer diameter side and inner diameter side). This dimensional change allows for more flexible space utilization, enabling the arc centers to be positioned optimally for each layer to minimize circumferential length while maintaining manufacturing efficiency.
2Ease of manufacture
If the same arc magnet shape is used for all positions to reduce manufacturing cost, then manufacturing cost is reduced, but it becomes difficult to suppress rotor size
Solution Approach 1:
The patent applies universality by designing arc magnets with standardized shapes and dimensions that can be used across multiple positions (outer diameter side and both inner diameter side positions). This universal design simplifies manufacturing processes and reduces costs while the strategic positioning of these standardized magnets optimizes the rotor's overall size.
Solution Approach 2:
While maintaining standardized magnet shapes for cost efficiency, the patent introduces asymmetry in the positioning of these magnets, particularly placing inner diameter side arc magnets with their arc centers off the d-axis. This combination of standardized shapes with asymmetric positioning achieves both cost reduction and size suppression.
3Length of stationary object
If arc magnets are arranged to minimize circumferential length, then rotor size is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent segments the magnetic pole portion into distinct outer diameter side and inner diameter side regions, each with specific arc magnet arrangements. This segmentation allows for optimized positioning in each region to minimize circumferential length while maintaining manageable manufacturing complexity through systematic organization.
Solution Approach 2:
By using standardized arc magnet designs that can serve multiple positions, the patent reduces the variety of unique components needed, thereby simplifying manufacturing processes despite the complex spatial arrangement. The same basic magnet shape is used across different positions, 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 design effectively reduces manufacturing costs and suppresses the increase in rotor size by utilizing the same arc magnets for different portions, enhancing output performance through improved magnetic flux concentration and torque efficiency.
Implementation Method 1
enhancing output performance through improved magnetic flux concentration and torque efficiency
Data Source
AI summary
A rotor of a rotating electrical machine includes a substantially annular rotor core and a plurality of magnetic pole portions formed at predetermined intervals in a circumferential direction of the rotor core. Each magnetic pole portion includes an outer diameter side magnet portion configured by an outer diameter side circular arc magnet arranged so as to protrude radially inward and an inner diameter side magnet portion located radially inward of the outer diameter side magnet portion and configured by a pair of inner diameter side arc magnets arranged so as to radially inward of the radially outer magnet portion. Each arc magnet is an arc magnet in which an inner peripheral surface and an outer peripheral surface have the same arc center.