Rotor Iron Core Smooth End Surfaces for Magnet Installation
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Solution Overview
Problem
The surface magnet-type rotor manufacturing process is hindered by step differences between projecting sections and permanent magnets, leading to magnet loss and reduced manufacturing efficiency, and increased weight of rotary electrical machines, which negatively impacts fuel consumption in electric power steering devices.
Innovation Solution
The radial outer side end surfaces of second projecting sections are smoothly continuous with those of first projecting sections, preventing step differences and allowing for efficient magnet installation without reducing performance, by ensuring smooth movement and maintaining reluctance torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the height of the projecting sections is lowered to reduce step difference, then the step difference between projecting sections and permanent magnets is reduced, but the reluctance torque produced by the projecting sections is reduced
Solution Approach 1:
The invention introduces a new dimensional parameter - the radial-direction outer side end surface continuity - to resolve the contradiction. By ensuring smooth continuity in the radial direction between first and second projecting sections, the invention eliminates step differences without reducing projection height, thereby maintaining reluctance torque while improving manufacturing precision during magnet installation
2Force
If the structure of the rotary electrical machine is enlarged to suppress decrease in reluctance torque, then the reluctance torque is maintained, but the weight of the rotary electrical machine becomes greater
Solution Approach 1:
The invention changes the geometric parameters of the projecting sections by ensuring smooth continuity of radial-direction outer side end surfaces between first and second projecting sections. This parameter optimization allows maintaining sufficient projection height for adequate reluctance torque while avoiding unnecessary structural enlargement, thereby preventing weight increase in the rotary electrical machine
3Adaptability or versatility
If a step difference occurs between projecting sections and permanent magnets, then the structure can accommodate different heights, but the magnets may catch on the step difference, be lost and the manufacture becomes laborious
Solution Approach 1:
The invention applies the principle of smooth continuity by ensuring that the radial-direction outer side end surfaces of first and second projecting sections are smoothly continuous. This curved/continuous surface design eliminates abrupt step differences that cause magnets to catch, allowing magnets to be installed smoothly without loss or rework, thereby improving manufacturing efficiency while maintaining adaptability
Data Source
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AI summary
A rotor iron core has first and second iron cores which overlap mutually in a direction along an axis line. The front iron core includes a first iron core main body and a plurality of first projecting sections which project to a radial outer side from an outer circumferential section of the first iron core main body. The second iron core includes a second iron core main body which overlaps with the first iron core main body and a plurality of second projecting sections which project to a radial outer side from an outer circumferential section of the second iron core main body. When the rotor iron core is viewed along the axis line, portions of the second projecting sections protrude as extension sections to outward in the circumferential direction, from the first projecting sections. Furthermore, when the rotor iron core is viewed along the axis line, radial-direction outer side end surfaces of the extension parts are smoothly continuous with radial-direction outer side end surfaces of the first projecting sections.