Induction Torque Motor Rotor Using Low Resistivity Soft Magnetic Material
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Solution Overview
Problem
Induction torque motors face limitations in achieving high performance efficiency due to the materials used in their rotors, which affect the conversion of electrical energy into mechanical energy.
Innovation Solution
The rotor of the induction torque motor is designed with a shaft member and a concentric cylindrical member made of a soft magnetic material with specific electric resistivity lower than or equal to 0.4 µΩ·m and relative permeability between 1000 and 50000, enhancing the motor's performance by optimizing the torque-to-loss ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional rotor materials are used in induction torque motors, then the motor structure is simple and easy to manufacture, but the performance efficiency (output torque to input power ratio) is limited
Solution Approach 1:
The patent applies parameter changes by selecting soft magnetic materials with specific electrical properties (electrical resistivity of 10-500 µΩ·cm and relative permeability of 100-5000). This changes the material parameters of the rotor to optimize the torque-to-loss ratio, thereby improving performance efficiency while maintaining manufacturing feasibility through the use of conventional soft magnetic materials like electrical steel sheets
Solution Approach 2:
The patent employs composite material structures by combining soft magnetic materials with specific electrical and magnetic properties in the rotor construction. The rotor uses stacked electrical steel sheets or sintered soft magnetic materials that composite multiple material characteristics to achieve both high efficiency and manufacturability
2Loss of energy
If the rotor material has high electrical resistivity, then eddy current losses are reduced, but the induced current generation and torque production are weakened
Solution Approach 1:
The patent resolves this contradiction by optimizing the electrical resistivity parameter to a specific range (10-500 µΩ·cm) that balances two opposing requirements: it is low enough to allow sufficient induced current generation for torque production, yet high enough to limit excessive eddy current losses. This parameter optimization enables simultaneous achievement of both goals
3Force
If the rotor material has high relative permeability, then magnetic flux concentration is improved, but magnetic saturation occurs more easily
Solution Approach 1:
The patent applies parameter changes by selecting soft magnetic materials with relative permeability in the range of 100-5000. This optimized permeability level provides sufficient magnetic flux concentration for effective torque generation while avoiding the excessive permeability that would lead to early magnetic saturation, thereby maintaining reliability across different operating conditions
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 significantly improves the efficiency of the induction torque motor by maintaining torque at a constant level even with slight slips, providing a more reliable and efficient conversion of electrical energy into mechanical energy.
Implementation Method 1
an induction current is generated in a rotor, which is an electric conductor, due to a rotating magnetic field generated by a stator. Thus, rotation torque corresponding to slip is obtained
Implementation Method 2
a cylindrical member that is concentrically connected to the shaft member and that is formed of a soft magnetic material having a specific electric resistivity lower than or equal to 0.4 µΩ·m and a relative permeability higher than or equal to 1000 and lower than or equal to 50000
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A rotor (1) for an induction torque motor according to the present invention comprises an axial body (1a) and a cylindrical body (1b) which is coupled to the axial body (1a) coaxially with the core of the axial body (1a) and is formed with a soft magnetic material wherein the specific electric resistivity is 0.4 [[mu]ohmsm] or less and the specific magnetic permeability is 1000 to 50000. An induction torque motor (TM) according to the present invention comprises the rotor (1) for an induction torque motor. Therefore, the rotor (1) for an induction torque motor and the induction torque motor (TM) according to the present invention can further improve performance.