Thermally Conductive Propeller Hub for Motor Heat Dissipation
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Solution Overview
Problem
Electric motors in propeller-driven unmanned aerial vehicles (UAVs) face performance degradation and potential failure due to heat management issues, as increased temperature affects winding resistance and permanent magnet flux density, leading to reduced torque and efficiency, and vulnerability to particle interference in small air gaps.
Innovation Solution
A propeller drive assembly with a thermally conductive plastic hub and blades, along with a thermally conductive interface material, enhances heat transfer from the motor to the surrounding air, utilizing materials like CoolPoly E-series thermally conductive plastic and thermally conductive greases to maintain motor efficiency and prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional motor cooling methods are used, then motor temperature can be reduced, but motor efficiency and power output decrease due to increased air gaps vulnerable to particle interference
Solution Approach 1:
The patent combines the propeller hub with the motor cooling function by making the hub thermally conductive. The hub serves dual purposes: mechanical connection of the propeller to the motor rotor, and thermal conduction path from the motor windings to dissipate heat. This eliminates the need for separate cooling mechanisms that would require additional air gaps.
Solution Approach 2:
The propeller hub is designed with multi-functionality: it provides mechanical support for the propeller blades, maintains aerodynamic properties for efficient propulsion, and simultaneously acts as a thermally conductive heat sink for motor cooling. This universal design eliminates the trade-off between cooling effectiveness and motor efficiency.
2Temperature
If thermally conductive materials are used in the propeller hub, then heat dissipation improves, but manufacturing complexity increases
Solution Approach 1:
The patent employs composite materials in the propeller hub that combine structural integrity with thermal conductivity. These composite materials allow the hub to maintain mechanical strength and aerodynamic properties while providing efficient thermal conduction pathways for motor cooling.
Solution Approach 2:
The patent modifies the thermal conductivity parameter of the propeller hub material to optimize heat dissipation. By selecting materials with appropriate thermal conductivity values, the design achieves effective cooling without requiring complex active cooling systems or multiple components.
3Reliability
If small air gaps are used in motor design, then motor efficiency increases, but vulnerability to particle interference increases causing seizure
Solution Approach 1:
The patent extracts the cooling function from the traditional air gap space and relocates it to the propeller hub. This eliminates the need for large air gaps that would be required for passive cooling, allowing the motor to maintain small air gaps for high efficiency without the risk of particle-induced seizure.
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 reduces motor operating temperature, maintaining efficiency and power output while preventing overheating and particle-induced failures, by utilizing thermally conductive materials for efficient heat dissipation and convective transfer.
Implementation Method 1
a propeller having a hub and one or more opposing blades projecting from said hub, said hub being mechanically secured to said rotor and comprising a thermally conductive plastic so that heat generated in said motor is transferred to said surrounding air through said hub
Implementation Method 2
heat generated in said motor is transferred to said surrounding air through said hub
Implementation Method 3
a thermally conductive interface material positioned between said rotor and said hub, the thermally conductive interface material having a coefficient of thermal conductivity greater than or equal to a coefficient of thermal conductivity of said hub
Data Source
AI summary
A propeller drive assembly includes an electric motor having a stator and a rotor. During operation the motor generates heat. A propeller made from a thermally conductive plastic includes a hub that is secured to the rotor portion of the motor so that the heat generated within the motor is transferred by conductance through the thermally conductive hub and propeller and then, by convection, is absorbed by the surrounding air, as the propeller rotates through the air. A thermally conductive interface material can be positioned between the rotor portion of the motor and the hub of the propeller to increase the thermal efficiency of the heat transfer between the motor and the propeller. A thermally conductive grease can be used as the interface material and an O-ring seal can be provided about the rotor to prevent the grease from escaping during motor operation.