Propeller Blade Geometry for Air-Cooled Electric Propulsion Motors
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Solution Overview
Problem
Electric vertical taking-off and landing machines face challenges in efficiently cooling their motors, which leads to decreased motor efficiency and potential reliability and safety issues due to high temperatures.
Innovation Solution
An electric propulsion device is designed with a propeller that includes a rotary boss secured to the motor's rotating shaft and blades with a base end portion that has an airfoil shape continuously changing such that the trailing edge becomes parallel to the rotating shaft, facilitating air cooling of the motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If oil-cooling or water-cooling mechanism is incorporated to cool the motor, then motor cooling effectiveness is improved, but machine body weight increases
Solution Approach 1:
The patent employs air cooling instead of liquid cooling systems. The propeller blades are designed to generate airflow that passes through the motor housing, carrying away heat from the motor. This pneumatic cooling approach eliminates the need for heavy oil or water cooling mechanisms while effectively controlling motor temperature.
Solution Approach 2:
The propeller serves dual functions: generating propulsion thrust and cooling the motor through generated airflow. The blade design creates controlled airflow patterns that simultaneously achieve flight propulsion and motor cooling, eliminating the need for separate cooling systems and reducing overall weight.
2Weight of moving object
If air-cooling mechanism is used to cool the motor, then machine body weight is reduced, but cooling efficiency may be insufficient
Solution Approach 1:
The propeller blades feature localized variations in airfoil shape, particularly in the base end portion where the trailing edge is parallel to the rotating shaft. This local geometric modification creates specific airflow patterns that direct cool air through the motor housing, enhancing cooling efficiency at critical locations without adding weight.
Solution Approach 2:
The patent modifies the airfoil parameters of the propeller blades, specifically making the trailing edge parallel to the rotating shaft in the base end portion. This parameter change optimizes the airflow characteristics, increasing the velocity and direction of cooling air through the motor, thereby improving air cooling effectiveness.
3Power
If the motor operates at high load to provide propulsion force, then flight performance is improved, but motor temperature increases and efficiency decreases
Solution Approach 1:
The system uses its own operational characteristics to solve the cooling problem. The propeller, driven by the motor at high load, generates airflow that automatically cools the motor. The higher the motor load and propeller speed, the stronger the cooling effect, creating a self-regulating thermal management system.
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 effectively increases motor efficiency by utilizing air cooling, thereby enhancing the reliability and safety of the aircraft by preventing motor overheating.
Implementation Method 1
the present invention relates to an electric propulsion device capable of cooling a motor by air
Data Source
AI summary
Provided is an electric propulsion device 106 including a propeller 131 and a motor 121 for rotating the propeller, wherein the propeller includes a rotary boss 132 secured to a rotating shaft 123 of the motor, and blades 133 protruding radially outward from the rotary boss. Further, the blades include a base end portion with an airfoil continuously changing such that a trailing edge comes to be in parallel to the rotating shaft of the motor from a radially outer side to the rotary boss, in a vicinity of the rotary boss.