Electric Motor Rotor Weight Imbalance Reduction
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Solution Overview
Problem
Existing electric motor rotors face challenges in reducing weight imbalance, leading to vibration and noise, particularly at high speeds, due to centrifugal forces caused by displaced centers of gravity, and existing solutions like raised parts or rotational buildup are complex and costly.
Innovation Solution
A rotor design featuring an iron core formed by stacking core sheets with predetermined shapes, where the angles of the stacked bodies in the rotation direction differ, reducing weight imbalance by offsetting thickness deviations and eccentricity, and a manufacturing method that simplifies the assembly process by using shear droop surfaces as guides for precise fitting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the iron core is press-fitted on raised parts on the rotary shaft surface, then weight imbalance is reduced and vibration is minimized, but the device complexity and manufacturing cost increase
Solution Approach 1:
The invention removes the raised parts from the rotary shaft and transfers the positioning function to protrusions formed directly on the iron core itself. This extraction simplifies the overall structure by eliminating unnecessary components while maintaining the weight balance function through the core's own geometric features
Solution Approach 2:
The invention combines the weight balance function and the positioning function into a single integrated structure. The protrusions on the iron core simultaneously serve to position the core on the shaft and to provide the necessary weight distribution, merging multiple functions into one component rather than requiring separate raised parts on the shaft
2Object-affected harmful factors
If rotational buildup is performed to reduce weight imbalance, then vibration is reduced, but the manufacturing cost and process complexity increase
Solution Approach 1:
The invention performs weight balance correction during the initial core formation process rather than requiring subsequent rotational buildup operations. The protrusions are formed as integral features of the core during stamping or pressing, allowing weight balance to be achieved in the primary manufacturing step without additional complex processes
3Speed
If the center of gravity of the rotor is displaced from the central axis, then centrifugal force is generated at high speeds, but this causes increased vibration and noise
Solution Approach 1:
The protrusions on the iron core act as counterweights that compensate for mass distribution imbalances. By strategically positioning these protrusions, the center of gravity is aligned with the rotation axis, canceling out centrifugal force effects during high-speed rotation and eliminating the resulting vibration and 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
The design effectively reduces centrifugal force and vibration, leading to quieter operation and a simpler, more reliable rotor structure with reduced noise and increased manufacturing efficiency.
Implementation Method 1
centrifugal force proportional to a distance between the center of gravity and the central axis is generated by rotation of the rotor. Since the centrifugal force is proportional to a square of a rotation speed, the centrifugal force becomes large especially in a case where the rotor rotates at a high speed
Implementation Method 2
an iron core having a plurality of stacked bodies formed by stacking core sheets having a predetermined shape
Data Source
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AI summary
A rotor of an electric motor according to the present disclosure includes an iron core having stacked bodies formed by stacking core sheets having a predetermined shape, the iron core has a first stacked body and a second stacked body that are a plurality of stacked bodies, and the first stacked body and the second stacked body are disposed such that angles of the stacked bodies in a rotation direction of the rotor are different from each other. A method for manufacturing a rotor of an electric motor according to the present disclosure is a method for manufacturing a rotor of an electric motor including an iron core including stacked bodies formed by stacking core sheets having a predetermined shape. The method includes preparing a first stacked body and a second stacked body as a plurality of stacked bodies and forming the iron core by disposing the first stacked body and the second stacked body such that angles of the first stacked body and the second stacked body in a rotation direction of the rotor are different from each other.