Embedded Magnet Rotor Core Layout for Faster Torque Response
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Solution Overview
Problem
Existing embedded magnet type rotary motors struggle to improve the responsiveness of torque change while maintaining torque levels, due to limitations in existing technologies.
Innovation Solution
The embedded magnet type rotary motor incorporates a rotor core with permanent magnets positioned at the outer circumference, spaced circumferentially, and lightening holes with inclined wall surfaces that approach the rotation axis, optimizing magnetic force distribution and reducing moment of inertia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If lightening holes are formed in the rotor core to reduce weight and improve responsiveness, then the response of torque change is improved, but torque is reduced
Solution Approach 1:
The lightening holes are provided only in specific regions of the rotor core (outer circumferential portion at the N pole or S pole), not throughout the entire rotor core. This localized approach reduces weight and improves responsiveness while preserving the structural integrity and magnetic properties in critical areas, thereby maintaining torque output.
Solution Approach 2:
The lightening holes are asymmetrically positioned in the rotor core, specifically located only at the outer circumferential portion corresponding to either the N pole or S pole region. This asymmetric configuration optimizes the balance between weight reduction and torque maintenance by strategically placing holes where they have the greatest impact on responsiveness while minimizing their impact on torque-generating regions.
2Speed
If the rotor core weight is reduced to improve responsiveness, then the response of torque change is improved, but the structural strength is reduced
Solution Approach 1:
The lightening holes are confined to specific regions (outer circumferential portion at N or S pole) rather than being distributed throughout the entire rotor core. This localized weight reduction maintains structural strength in critical load-bearing areas while achieving the desired responsiveness improvement.
Solution Approach 2:
The rotor core is segmented into regions with different densities - the lightening holes create void spaces in non-critical areas while maintaining solid structure in critical areas. This segmentation allows weight reduction without compromising overall structural reliability.
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 configuration enhances the response of torque change while effectively suppressing torque reduction, leading to improved motor control and efficiency.
Implementation Method 1
the outer circumferential wall surface portion has an inclined wall surface portion that approaches the rotation axis as it moves from the center of one of the plurality of permanent magnets toward the magnetic pole side
Implementation Method 2
the rotor core has a plurality of lightening holes spaced from each other in the circumferential direction on the rotation axis side of the plurality of permanent magnets
Data Source
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AI summary
An embedded magnet type rotary motor comprising: a stator; and a rotor having a rotor core with a plurality of permanent magnets embedded therein and held inside the stator for rotation around a rotation axis, wherein the plurality of permanent magnets are held in the outer circumference of the rotor core, spaced from each other in a circumferential direction, and have magnetic poles at both ends in the circumferential direction; the rotor core has a plurality of lightening holes spaced from each other in the circumferential direction on the rotation axis side of the plurality of permanent magnets; each of the plurality of lightening holes has a bottom wall surface portion extending in the circumferential direction on the rotation axis side, an outer circumferential wall surface portion on the outer circumferential side, and a side wall surface portion connecting between the bottom wall surface portion and the outer circumferential wall surface portion; and the outer circumferential wall surface portion has an inclined wall surface portion that approaches the rotation axis as it moves from the center of one of the plurality of permanent magnets toward the magnetic pole side.