Lightweight Inner-Rotor Motor for Flying Devices
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Solution Overview
Problem
The existing inner-rotor-type motors for small flying devices are heavy due to the use of dense materials like electromagnetic steel plates, which hinders weight reduction and increases the risk of dust and chemical contamination, while outer-rotor-type motors lack dust-proofness.
Innovation Solution
A lightweight inner-rotor-type motor with a cylindrical permanent magnet and a reduced rotor yoke, featuring a stator with an annular yoke and teeth, and a rotor with anisotropically arranged magnetic poles, supported by bearings, to enhance dust-proofness and reduce weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an inner-rotor-type motor with electromagnetic steel plates is used, then dust-proofness is improved, but weight increases
Solution Approach 1:
The patent changes the material parameter of the rotor core from traditional electromagnetic steel plates (specific gravity ~7.65) to a resin material with filling particles (specific gravity ~2.0), achieving a 73% weight reduction while maintaining motor functionality through altered material composition
Solution Approach 2:
The patent employs composite materials by combining resin with filling particles in the rotor core, creating a lightweight composite structure that replaces dense electromagnetic steel plates while maintaining necessary mechanical and magnetic properties
2Weight of moving object
If an outer-rotor-type motor is used, then weight is reduced, but dust-proofness deteriorates
Solution Approach 1:
The patent inverts the traditional inner-rotor structure by placing the permanent magnet on the rotor periphery rather than at the center, creating an outer-rotor configuration that achieves weight reduction while the resin-based construction maintains dust-proofness
3Power
If traditional electromagnetic steel plates are used for rotor core, then magnetic circuit performance is maintained, but weight reduction is prevented
Solution Approach 1:
The patent changes the material parameters of the rotor core from high-density electromagnetic steel to a resin-based composite with filling particles, achieving dramatic weight reduction while the permanent magnet configuration maintains necessary magnetic circuit performance
Solution Approach 2:
The patent replaces the traditional steel-based magnetic circuit structure with a resin-based composite structure containing permanent magnets, substituting the mechanical material system to achieve weight reduction while maintaining electromagnetic functionality
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 solution provides a flying device with improved dust-proofness and reduced weight, enhancing its performance and industrial value by using a lightweight motor configuration that maintains mechanical strength and efficiency.
Implementation Method 1
a permanent magnet 8 of a cylindrical shape, having anisotropically arranged magnetic poles and positioned inside the stator core 4 via a gap
Implementation Method 2
The rotor 19 includes a permanent magnet 8 of a cylindrical shape, having anisotropically arranged magnetic poles
Data Source
AI summary
A flying device includes a plurality of rotary vanes, a motor element serving as a driving source for each of the plurality of rotary vanes, the motor element driving and rotating a main shaft of the rotary vanes, and a drive circuit. The motor element includes a stator, a rotor, and a pair of bearings. The stator includes a stator core having an annular yoke and a plurality of teeth projecting inward from the annular yoke, and stator windings wound respectively around the plurality of teeth of the stator core. The rotor includes a permanent magnet of a cylindrical shape located inside the stator core via a gap, the permanent magnet being positioned counter to the plurality of teeth, a rotor yoke in contact with a cylindrical inner wall surface of the permanent magnet, and a shaft pivotally supported at an axis of the rotor yoke, the shaft being connected to the main shaft. The pair of bearings pivotally support the shaft to allow the shaft to rotate freely, and are located respectively on both sides of a direction of a rotating shaft of the rotor. The permanent magnet has anisotropically arranged magnetic poles, and a number of the magnetic poles is P representing an even number. The permanent magnet is configured such that the rotor yoke is smaller in weight than the permanent magnet. The drive circuit controls a stator current supplied to the stator windings.