External Rotor Motor Airflow Structure for Magnet Cooling
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Solution Overview
Problem
Existing external rotor motors with internally cooled stators suffer from insufficient cooling of the permanent magnets, leading to reduced efficiency due to elevated temperatures.
Innovation Solution
The rotor design includes a back-iron ring with permanent magnets, a carrier connecting the back-iron ring to the shaft, and circulation openings and flow guide ribs for air circulation, combined with a liquid-cooled stator to enhance cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the rotor design includes circulation openings and flow guide ribs for air circulation, then the temperature distribution in the motor becomes more even, but the device complexity increases
Solution Approach 1:
The rotor structure serves itself by using its own rotation to drive the air circulation. The circulation openings and flow guide ribs are designed to automatically generate air flow paths through the rotor interior during rotation, eliminating the need for external fans or pumps for rotor cooling.
Solution Approach 2:
The flow guide ribs are designed with specific geometric parameters (angles, heights, spacing) that optimize air flow patterns. By carefully selecting these parameters, effective cooling is achieved without excessive complexity in the rotor structure.
2Temperature
If two cooling mechanisms (liquid-cooled stator and air circulation in rotor) are combined, then cooling efficiency is enhanced, but the device complexity increases
Solution Approach 1:
The liquid cooling channels in the stator and air circulation paths in the rotor are merged into a unified cooling system. The two cooling mechanisms work together synergistically, with liquid cooling handling stator heat and air circulation handling rotor heat, creating a comprehensive thermal management solution.
Solution Approach 2:
The air circulation system serves multiple functions: it cools the permanent magnets, removes heat from the rotor interior, and works in conjunction with the liquid cooling system. The same air flow paths serve both cooling and temperature distribution uniformity functions.
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 achieves more even temperature distribution within the motor, reducing the temperature of the permanent magnets and thereby improving the motor's efficiency and performance.
Implementation Method 1
The rotor can cause air circulation during operation, which leads to a more even temperature distribution in the electric motor and thus reduces the temperature of the permanent magnets
Implementation Method 2
The stator surrounds an interior in which a channel for cooling liquid runs
Data Source
AI summary
An electric motor has a shaft, a stator with windings, and a rotor surrounding the stator and having a back-iron ring. Permanent magnets are arranged on an inner side of the back-iron ring, and a carrier connects the back-iron ring to the shaft. A housing encloses the rotor and the stator and has an opening through which the shaft projects. The carrier has several circulation openings and several flow guide ribs for air circulation in one end face.