Rotor, rotating electric machine, electric compressor, and refrigeration/air-conditioning apparatus
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Solution Overview
Problem
Conventional rotating electric machines with reduced connection portion thickness to minimize magnetic short circuits and leakage magnetic flux do not adequately decrease the cross-sectional area, leading to insufficient strength and magnetic resistance.
Innovation Solution
A rotor design featuring a radial connection portion with minimum width portions and a circumferential connection portion having a uniform and non-uniform thickness, where the thickness increases from a minimum value, to enhance magnetic resistance while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the thickness of the connection portion is decreased to increase magnetic resistance, then leakage magnetic flux is reduced, but the strength of the connection portion becomes insufficient
Solution Approach 1:
The connection portion is designed with non-uniform thickness, featuring a thinned region with smaller thickness and a regular region with larger thickness. This local variation in thickness allows the thinned region to increase magnetic resistance and reduce leakage magnetic flux, while the regular region maintains structural strength and prevents core plate deformation under centrifugal force.
2Loss of energy
If the cross-sectional area of the connection portion is decreased to increase magnetic resistance, then leakage magnetic flux is reduced, but the structural integrity of the rotor core is compromised
Solution Approach 1:
The connection portion incorporates a thinned region with reduced cross-sectional area to increase magnetic resistance and reduce leakage magnetic flux. This local modification is strategically positioned to affect magnetic flux distribution without compromising the overall structural integrity of the rotor core.
Solution Approach 2:
Instead of uniformly decreasing the cross-sectional area of the connection portion, the invention introduces a thickness dimension variation within the connection portion itself. The thinned region has smaller thickness compared to the regular region, creating a three-dimensional structure that optimizes both magnetic resistance and structural strength.
3Loss of energy
If coining is performed to thin the connection portion, then magnetic resistance is increased, but the range of thinned portion is limited and cross-sectional area reduction is insufficient
Solution Approach 1:
The connection portion is designed with a thinned region that has smaller thickness compared to the regular region. This local quality variation allows for sufficient cross-sectional area reduction in the thinned region, thereby increasing magnetic resistance and reducing leakage magnetic flux more effectively than conventional coining methods.
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
The design effectively reduces leakage magnetic flux and ensures sufficient strength, improving the efficiency of the rotating electric machine by spreading stress concentrations and increasing magnetic resistance.
Implementation Method 1
rotates the rotor by interaction between a magnetic field generated by each permanent magnet embedded in the rotor and a magnetic field generated by applying a current to a coil provided in a stator
Implementation Method 2
a magnetic field generated by applying a current to a coil provided in a stator
Implementation Method 3
a part of a magnetic flux generated from the permanent magnet embedded in each magnet insertion hole does not reach the stator, and a magnetic short circuit occurs in which a loop is formed
Data Source
AI summary
A rotor core is configured by stacking a plurality of core plates each including: an inner peripheral side core portion; an outer peripheral side core portion; a magnet insertion hole; a radial connection portion to be connected to the inner peripheral side core portion; a circumferential connection portion to be connected between the outer peripheral side core portion and the radial connection portion, including a minimum width portion having a width smaller than widths at both ends, and having a width smoothly decreasing from both ends toward the minimum width portion; and a thin portion including a uniform thickness portion which is provided in the circumferential connection portion and which has a uniform thickness and a non-uniform thickness portion which is adjacent to the uniform thickness portion and which has an increasing thickness, the thin portion having the minimum width portion within the uniform thickness portion.