Integrated Fan-Flywheel BLDC Motor for High Inertia Cooling
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Solution Overview
Problem
Brushless DC motors in electric machining devices have a low moment of inertia due to their design, which limits their rotational energy and efficiency in machining operations, and they also face challenges in achieving sufficient cooling and compact size.
Innovation Solution
The flywheel is partially enclosed by the fan axially along the motor shaft, with the fan completely surrounding it in the radial direction, creating a robust and reliable design with high torque, and is manufactured from materials like brass or iron for high inertia and density, eliminating the need for balancing and ensuring a secure, noise-free, and efficient cooling air flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the rotor diameter is reduced to achieve high power density, then the motor size is reduced, but the moment of inertia and stored rotational energy decrease significantly
Solution Approach 1:
The patent combines the cooling fan and flywheel into a single integrated component that rotates together with the rotor. The fan blades are formed as extensions of the flywheel structure, creating a unified assembly that performs both cooling and energy storage functions simultaneously, thereby increasing moment of inertia without significantly increasing motor size
Solution Approach 2:
The integrated fan-flywheel component serves multiple functions: it provides cooling air flow through the fan blades, stores rotational energy through the flywheel mass, and maintains rotational inertia to smooth out torque fluctuations. This multi-functionality resolves the contradiction by achieving high power density while maintaining sufficient moment of inertia through a single compact component
2Stability of the object's composition
If a separate flywheel is added to increase moment of inertia, then rotational energy is improved, but the overall device size and complexity increase
Solution Approach 1:
Instead of adding a separate flywheel component, the patent integrates the flywheel function directly into the cooling fan structure. The fan blades are designed as extensions of the flywheel mass, creating a single-piece or closely integrated assembly that eliminates the need for separate mounting and connection mechanisms, thereby reducing structural complexity while maintaining high moment of inertia
3Temperature
If the fan is designed to completely surround the flywheel radially, then cooling efficiency is improved, but the axial length of the motor increases
Solution Approach 1:
The patent optimizes the fan-flywheel geometry by designing the fan blades to extend radially outward from the flywheel mass in a compact axial arrangement. The blades are positioned to create effective cooling air flow paths without requiring excessive axial length, achieving efficient cooling through optimized radial and axial dimension proportions rather than simply increasing overall size
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 configuration enhances the motor's efficiency, torque, and reliability while maintaining a compact size, allowing for direct installation without balancing and effective cooling, thus meeting the requirements of high moment of inertia and compactness.
Implementation Method 1
a fan for cooling the stator and/or the rotor of the brushless DC motor, wherein the fan and the flywheel are arranged for conjoint rotation on the motor shaft, with the flywheel being enclosed at least partially by the fan axially along the motor shaft
Implementation Method 2
the flywheel has very high inertia, a very high shaft pressure and a very high homogeneous density
Data Source
AI summary
A brushless direct current motor of an electrical machining device includes a stator, a rotor, a fan and a flywheel. The rotor, the fan and the flywheel are arranged for conjoint rotation on a motor shaft of the brushless direct current motor. The flywheel is at least partly surrounded axially along the motor shaft by the fan. The brushless direct current motor may be incorporated in a hand-held power tool.