Squirrel-Cage Rotor Balance via End Ring Brazing Deformation
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Solution Overview
Problem
Squirrel-cage rotors for electric motors face challenges in achieving balance and reducing vibration and noise due to rotary imbalance, with existing methods like attaching balance weights or using putty being costly and prone to detachment, and requiring complex production processes.
Innovation Solution
The method involves adjusting the amounts of material used for bonding in squirrel-cage rotors by deforming end rings and applying brazing material to improve rotor balance, providing mechanical and electrical connections that enhance stability and efficiency without adding new parts, allowing for separate steps to measure and correct imbalance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If balance weights are attached to the rotor, then rotor balance is improved, but device complexity and production cost increase
Solution Approach 1:
The patent merges the balance weight function with the end ring structure by forming protrusions directly on the end ring that serve as balance weights. This eliminates separate balance weight parts and their attachment steps, reducing device complexity while maintaining rotor balance improvement.
Solution Approach 2:
The end ring is given multiple functions: it serves as both the structural component connecting conductor bars and as the balance weight carrier through formed protrusions. This multi-functionality reduces the total number of parts needed in the rotor assembly.
2Manufacturing precision
If putty is applied to improve balance, then rotor balance is improved, but reliability decreases due to detachment risk
Solution Approach 1:
The patent replaces the putty material with metal protrusions formed from the end ring itself. These metal structures provide permanent, reliable balance correction without the detachment issues of organic materials like putty, effectively using a more durable material to replace a temporary solution.
3Manufacturing precision
If drilling or shaving is used to remove weight, then rotor balance is improved, but manufacturing complexity and waste increase
Solution Approach 1:
The balance correction features (protrusions) are formed during the end ring manufacturing process itself, before the rotor assembly is completed. This preliminary formation of balance features eliminates the need for subsequent drilling or shaving operations, simplifying the manufacturing process and reducing waste.
4Manufacturing precision
If separate balance weights are manufactured and attached, then rotor balance is improved, but production time and cost increase
Solution Approach 1:
The patent combines the end ring manufacturing and balance weight formation into a single integrated process. The protrusions are formed directly on the end ring during its production, eliminating the separate manufacturing and attachment steps for balance weights, thereby improving production efficiency.
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 approach results in a well-balanced rotor with higher reliability and lower production costs, as it strengthens electrical continuity and reduces vibration and noise, while allowing for easier adjustment of balance through controlled brazing material quantities.
Implementation Method 1
quantities of the braze used to bond various components of the rotor differing from each other by an amount to improve balance of the rotor
Implementation Method 2
heated to a prescribed temperature or melting point of the brazing material
Implementation Method 3
pressing is moved toward outer surfaces of the end rings to deform the end rings
Data Source
AI summary
To provide a well balanced squirrel-cage rotor for an electric motor, quantities of braze used to bond various rotor components are different from each other so as to serve as balance weight in order to improve balance.