Magnet Embedded Motor Rotor Core Using Nanocrystalline and Amorphous Materials
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Solution Overview
Problem
In interior permanent magnet motors, increasing rotor speed enhances counter electromotive voltage, while reducing magnetic flux density to mitigate this increases torque loss.
Innovation Solution
A magnet embedded type motor design featuring a stator and rotor with laminated metal foils, radially arranged magnets, and specific magnetic flux leakage prevention structures made of nanocrystalline and amorphous soft magnetic materials to manage magnetic flux and torque effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If rotor speed is increased, then motor output is improved, but counter electromotive voltage increases
Solution Approach 1:
The patent applies local quality by using different soft magnetic materials (nanocrystalline vs. amorphous) in different regions of the rotor core. Specifically, the first soft magnetic material with different magnetic properties from the second soft magnetic material is used in specific portions of the rotor core to locally control magnetic flux distribution, thereby reducing counter electromotive voltage while maintaining motor output.
2Use of energy by moving object
If magnetic flux density is decreased, then counter electromotive voltage is reduced, but torque decreases
Solution Approach 1:
The patent uses local quality by implementing regions with different magnetic flux densities within the rotor core. The first soft magnetic material is used in portions where magnetic flux concentration is beneficial for torque generation, while the second soft magnetic material is used in portions where flux density reduction helps lower counter electromotive voltage, achieving both objectives simultaneously.
Solution Approach 2:
The patent employs composite materials by combining two different soft magnetic materials (nanocrystalline and amorphous) in the rotor core. Each material contributes different magnetic properties, allowing the composite structure to optimize both torque generation and counter electromotive voltage reduction that cannot be achieved with a single material.
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 reduces counter electromotive voltage while maintaining torque, improving motor efficiency and output, especially at high speeds.
Implementation Method 1
the rotor core has a pair of radially arranged magnet holes, a center side magnetic flux leakage prevention hole, and center side bridge portions for each magnetic pole
Implementation Method 2
In the rotor core, the center side bridge portion, a center portion on the center side with respect to the outer peripheral portion, and an inter-magnetic pole portion between the magnetic poles mutually adjacent in the circumferential direction are made of a nanocrystalline soft magnetic material, and another portion is made of an amorphous soft magnetic material
Implementation Method 3
heating the center side bridge portion, a center portion, and an inter-magnetic pole portion of the metal foil to transform the heated portions to a nanocrystalline soft magnetic material while keeping a part other than the center side bridge portion, the center portion, and the inter-magnetic pole portion to an amorphous soft magnetic material
Implementation Method 4
heating the center side bridge portion, a center portion, and an inter-magnetic pole portion of the metal foil to transform the heated portions
Data Source
AI summary
An magnet embedded type motor capable of reducing a counter electromotive voltage while suppressing reduction of a torque is provided. The magnet embedded type motor of the present disclosure includes a stator and a rotor rotatably disposed inside the stator. The rotor includes a rotor core and a plurality of magnet groups embedded in the rotor core along a circumferential direction, the rotor core includes a plurality of laminated metal foils. The rotor core has a pair of radially arranged magnet holes, a center side magnetic flux leakage prevention hole, and center side bridge portions for each magnetic pole. A pair of radially arranged magnets are embedded in the radially arranged magnet holes. In the rotor core, the center side bridge portion, a center portion, and an inter-magnetic pole portion are made of a nanocrystalline soft magnetic material, and another portion is made of an amorphous soft magnetic material.