Motor Rotor Bonding Structure for High-Speed Magnetic Bridge Strength
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Solution Overview
Problem
The existing permanent-magnet synchronous motors in electric vehicles face a limitation in maximum speed due to the vulnerability of magnetic bridges in the rotor core to centrifugal forces at high speeds, leading to reduced robustness and lower torque density.
Innovation Solution
A motor rotor apparatus with a non-magnetic high-hardness bonding element embedded in the rotor core, featuring air sub-grooves with teeth and slots, which forms a bearing structure to absorb centrifugal forces and distribute stress, thereby enhancing the rotor's robustness and increasing the motor's maximum speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the quantity of air regions in the rotor is increased to increase magnetic reluctance torque, then the magnetic reluctance torque increases, but the magnetic bridge is prone to damage due to centrifugal force at high speeds, decreasing rotor robustness
Solution Approach 1:
The patent applies composite materials by combining non-magnetic high-hardness materials (such as aluminum or ceramic) with the rotor core material. The bonding element made of non-magnetic high-hardness material is embedded in the rotor core to reinforce the magnetic bridge structure, enabling it to withstand centrifugal forces at high speeds while maintaining the air regions needed for magnetic reluctance torque
Solution Approach 2:
The patent applies local quality by strategically placing the bonding element specifically at the magnetic bridge region where structural reinforcement is needed. The bonding element is embedded in the rotor core at the location of the magnetic bridge to provide localized strengthening without affecting other parts of the rotor, thus maintaining rotor robustness while preserving the air region configuration for torque generation
2Power
If the quantity of air regions in the rotor is increased to increase magnetic reluctance torque, then the magnetic reluctance torque increases, but the maximum speed of the motor is restricted from reaching high speeds
Solution Approach 1:
The bonding element made of non-magnetic high-hardness material reinforces the magnetic bridge structure, enabling the rotor to withstand the centrifugal forces generated at high speeds. This structural reinforcement removes the speed limitation while maintaining the air region configuration necessary for magnetic reluctance torque generation
Solution Approach 2:
The patent changes the mechanical strength parameter of the rotor core by introducing the bonding element with high hardness and non-magnetic properties. This parameter change allows the rotor structure to withstand higher centrifugal forces, thereby enabling operation at higher speeds without compromising the magnetic bridge integrity
3Power
If permanent magnets are increased to increase permanent-magnet torque, then the permanent-magnet torque increases, but the use of rare earth resources increases and manufacturing costs increase
Solution Approach 1:
The patent converts the traditionally harmful effect of air regions (which weaken the magnetic bridge) into a beneficial feature by introducing the bonding element. The air regions are now used to generate magnetic reluctance torque, which complements the permanent-magnet torque, allowing for a reduction in permanent magnet quantity while maintaining or improving overall torque output
Solution Approach 2:
The patent changes the torque generation mechanism by introducing magnetic reluctance torque as an additional component. By modifying the rotor structure to include air regions with bonding element reinforcement, the motor can generate torque through magnetic reluctance in addition to permanent-magnet torque, reducing dependence on permanent magnets and rare earth resources
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 solution effectively disperses centrifugal forces, ensuring robustness at high speeds and increasing the motor's maximum speed while reducing the need for permanent magnets and rare earth resources, thus improving energy efficiency and power density.
Implementation Method 1
a centrifugal force generated by a motor rotor that rotates at a high speed is applied to the magnetic bridge
Implementation Method 2
The bonding element made of the non-magnetic material does not affect distribution of a magnetic field
Implementation Method 3
The stator magnetic field interacts with the rotor magnetic field to drive the permanent-magnet motor to rotate
Data Source
AI summary
A motor rotor apparatus includes a rotor core and a bonding element embedded in the rotor core. The rotor core includes a first air sub-groove, and the first air sub-groove includes a first tooth and a first slot. The bonding element includes a second tooth and a second slot. The first tooth is engaged with the second tooth, and the first slot is engaged with the second slot.