Torque Motor Thermal Coupling via Stationary Stator Plate
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Solution Overview
Problem
Brushed torque motors experience overheating due to insufficient conductive heat transfer paths, particularly in designs with gear reduction mechanisms, limiting their performance under high aerodynamic loads.
Innovation Solution
A torque motor design featuring a large area rotor and stator separated by a small air gap for frictionless thermal coupling, with the stator conductively coupled to the motor housing using thermal gap pads or high conductivity compounds, allowing efficient heat conduction regardless of rotor rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a gear reduction mechanism is used in the torque motor, then torque output is increased, but the conductive heat transfer path becomes insufficient causing rotor overheating
Solution Approach 1:
The patent introduces a stationary heat transfer plate as an intermediary component between the rotating rotor and the external environment. This plate provides a dedicated conductive heat transfer path that does not interfere with rotor rotation, allowing efficient heat removal from the rotor while maintaining the gear reduction mechanism for high torque output
Solution Approach 2:
The patent segments the heat transfer function from the mechanical drive function by using a separate stationary heat transfer plate independent of the gear reduction mechanism. This allows the gear mechanism to focus on torque multiplication while the separate plate handles thermal management, resolving the conflict between torque output and heat dissipation
2Temperature
If the air gap between rotor and stator is reduced to improve thermal coupling, then heat transfer efficiency increases, but friction and mechanical contact risks increase
Solution Approach 1:
The patent uses a stationary heat transfer plate as an intermediary that contacts the rotor through a minimal air gap. This plate absorbs heat from the rotor surface and conducts it away through its stationary mounting, providing efficient thermal coupling without requiring the rotor to maintain continuous mechanical contact or suffer from friction
Solution Approach 2:
The patent replaces mechanical thermal coupling (which would require direct contact and cause friction) with a near-contact air gap system. The minimal air gap provides sufficient thermal conduction while eliminating mechanical friction and wear, substituting a thermal field solution for a mechanical contact solution
3Temperature
If conventional cooling systems (fans or coolant) are added to the torque motor, then heat dissipation improves, but device complexity and reliability decrease
Solution Approach 1:
The patent implements a passive heat transfer system where the stationary plate automatically conducts heat from the rotor to the external environment through conduction and convection, without requiring active cooling components. The system uses natural thermal gradients and ambient air flow to remove heat, eliminating the need for fans, pumps, or coolant circulation systems
Solution Approach 2:
The patent extracts the cooling function from the rotating assembly and places it in a stationary component. By removing active cooling systems from the rotor-stator assembly and using a separate stationary heat transfer plate, the patent eliminates complex moving parts while maintaining effective heat dissipation
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 effectively dissipates heat, enabling the torque motor to counteract higher aerodynamic loads at faster aircraft speeds without the need for fans or coolant systems, and can be easily retrofitted into existing systems, significantly reducing armature temperature rises and increasing operational efficiency.
Implementation Method 1
Heat from the rotor is transferred to the stator by conduction. The air gap may have a dimension of about 0.002 to 0.003 inches.
Implementation Method 2
The stator may be conductively coupled to the torque motor housing by one of a thermal gap pad or high conductivity thermal gap filling compound.
Data Source
AI summary
A torque motor includes a large area rotor, a stator surrounding at least a portion of the rotor, and a small air gap separating the rotor from the stator to allow frictionless thermal coupling between the rotor and the stator. Heat from the rotor is transferred to the stator by conduction. The stator contacts an inner surface for a housing of the torque motor for conductively coupling to a cold environment air flow exterior to the torque motor housing. The air gap may have a dimension of about 0.002 to 0.003 inches. The stator may be conductively coupled to the torque motor housing by one of a thermal gap pad or high conductivity thermal gap filling compound. Heat conduction from the rotor to the stator preferably occurs without rotation of the rotor.