Curved Rotor Core Ribs for Rotating Electric Machine Stress Management
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Solution Overview
Problem
Existing rotors for rotating electric machines face challenges in managing centrifugal and press-fit stresses, particularly due to the rigidity and deformation of ribs, which affect the strength and weight distribution, leading to inefficiencies in stress reduction and performance.
Innovation Solution
The rotor design incorporates a rotor core with a through-hole and ribs that have curved shapes, allowing for increased rigidity and deformation absorption, with the first and second curved ribs crossing each other to enhance circumferential length and reduce stress, while maintaining high rigidity against centrifugal forces and allowing deformation under press-fit conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the ribs are arranged in a pinwheel configuration to reduce distortion, then the rib distortion in axial direction is reduced, but the rib strength and rigidity are compromised
Solution Approach 1:
The ribs are designed with curved surfaces instead of straight lines, where each rib has a curvature that bulges toward the outer circumference side. This curved configuration provides both distortion reduction and enhanced strength by distributing stresses more effectively across the rib structure while maintaining structural integrity under centrifugal forces.
2Strength
If the ribs are arranged in a spoke configuration to improve strength and reduce width, then the rib strength is improved and rotor core weight is reduced, but the rib rigidity against centrifugal forces is reduced
Solution Approach 1:
The curved rib configuration with bulging toward the outer circumference provides increased rigidity against centrifugal forces while maintaining the weight reduction benefits of the spoke arrangement. The curvature allows the ribs to better resist bending moments generated by rotation.
Solution Approach 2:
The rotor core employs composite construction with inner and outer circumference-side rotor cores connected by ribs, creating a structured composite that optimizes both strength and rigidity distribution throughout the rotor assembly.
3Stability of the object's composition
If the rotor core rigidity is increased to reduce deformation, then the stress reduction performance is improved, but the weight of the rotor core increases
Solution Approach 1:
The rotor core is divided into inner and outer circumference-side rotor cores connected by multiple ribs, creating a segmented structure that achieves high rigidity through the distributed rib network rather than increasing overall material quantity, thus controlling deformation without proportionally increasing weight.
Data Source
AI summary
A rotor for a rotating electric machine includes a rotor core, a plurality of permanent magnets, and a rotating shaft. The rotor core includes a through-hole, an inner circumference-side rotor core, an outer circumference-side rotor core, and a plurality of ribs. Each of the plurality of ribs includes a first curved rib and a second curved rib. The first curved rib extends to one side in a circumferential direction from an inner circumference side toward an outer circumference side. The first curved rib has a curved shape that bulges toward the outer circumference side and toward another side in the circumferential direction beyond a straight line that connects a first connecting portion between the first curved rib and the inner circumference-side rotor core and a second connecting portion between the first curved rib and the outer circumference-side rotor core.