Permanent Magnet Motor Stator Rigidity and Vibration Control
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Solution Overview
Problem
Existing permanent magnet motors face challenges in reconciling reductions in size and increases in output with reductions in vibration and noise, as concentrated-winding motors reduce rigidity and increase vibration noise, while distributed-winding motors increase armature resistance and reduce output efficiency.
Innovation Solution
A permanent magnet motor design featuring a stator core with radially inward protruding teeth and a connecting portion between adjacent teeth, along with a frame that holds the stator core, where the armature winding is concentrated and the inner circumferential ends of adjacent teeth are connected, optimizing the radial thickness of the core back and frame to achieve balanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If concentrated-winding motor is used, then output is increased and size is reduced, but rigidity of teeth is reduced and vibration noise increases
Solution Approach 1:
The invention divides the stator core into multiple teeth with connecting portions between them, segmenting the structure to maintain rigidity while accommodating concentrated windings. The connecting portions act as separate structural elements that reinforce the overall stator core rigidity without interfering with the concentrated winding configuration.
Solution Approach 2:
The invention uses a composite structure combining the stator core teeth with connecting portions made of magnetic material. This composite construction provides both the magnetic functionality needed for concentrated windings and the structural rigidity to reduce vibration noise, resolving the contradiction between power output and vibration control.
2Object-affected harmful factors
If distributed-winding motor is used, then rigidity of teeth is raised and vibration noise is reduced, but armature resistance is increased and output efficiency is reduced
Solution Approach 1:
The invention applies local quality by providing connecting portions only at specific locations between adjacent teeth, rather than throughout the entire stator core. This localized reinforcement maintains rigidity to reduce vibration noise while minimizing interference with the concentrated winding configuration, thereby preserving output efficiency.
Solution Approach 2:
Instead of using distributed windings to achieve rigidity, the invention inverts the approach by maintaining concentrated windings for high efficiency and achieving rigidity through the connecting portions structure. This reversal of the conventional approach resolves the contradiction between vibration reduction and output efficiency.
3Power
If radial thickness of core back is reduced to increase slot cross-sectional area, then output is increased, but rigidity of stator core decreases and vibration noise increases
Solution Approach 1:
The invention addresses the rigidity issue by adding structural elements in a different dimension - the connecting portions extend between teeth in the circumferential direction. This dimensional addition provides rigidity without increasing the radial thickness, allowing slot cross-sectional area to be increased while maintaining stator core rigidity.
4Volume of moving object
If radial thickness of frame is reduced to decrease motor size, then size is reduced, but frame rigidity decreases and vibration noise increases
Solution Approach 1:
The invention merges the frame's vibration reduction function with the stator core structure by incorporating connecting portions that extend from the teeth to the frame. This integration allows the frame to maintain rigidity against vibration without requiring increased radial thickness, thus reducing motor size while controlling vibration noise.
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 vibration and noise while maintaining compact size and high output, by ensuring the stator core's rigidity and slot cross-sectional area are optimized, thereby improving motor efficiency and reducing electromagnetic vibrational forces.
Implementation Method 1
a rotor that includes a rotor core and permanent magnets. The armature winding is constituted by a plurality of coils that are respectively wound so as to be concentrated on the teeth
Implementation Method 2
reductions in vibration and noise can be reconciled with reductions in size and increases in output in the permanent magnet motor
Data Source
AI summary
A permanent magnet motor includes: a stator including: a stator core in which teeth are respectively arranged circumferentially so as to protrude radially inward from an annular core back; an armature winding that is mounted to the stator core; and a frame that holds the stator core in an internally fitted state; and a rotor that includes a rotor core and permanent magnets, the armature winding being constituted by a plurality of coils that are respectively wound so as to be concentrated on the teeth, wherein: inner circumferential ends of adjacent teeth are connected together by a connecting portion; and 0.122≦(t2+t3)/r4≦0.202 is satisfied, where t2 is a thickness of the core back, t3 is a thickness of the frame, and r4 is an outside radius of the frame.