Variable-Porosity Gearbox Enclosure for Cooling and Load Bearing
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Solution Overview
Problem
Rotary-wing aircraft transmissions generate significant heat due to friction, requiring external heat exchangers that can lead to fluid leakage and weight penalties, necessitating a solution for reduced heat exchanger reliance and enhanced load-bearing capabilities.
Innovation Solution
A gearbox enclosure with an external liner, internal liner, and a variable porosity region that supports lubricant flow and load-bearing capabilities, utilizing additive manufacturing to create a lattice structure that dissipates heat and supports structural loads, reducing the need for external heat exchangers and load-bearing structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an external heat exchanger is used to remove heat from the transmission, then heat dissipation is improved, but the risk of fluid leakage and system complexity increases
Solution Approach 1:
The patent combines the heat dissipation function with the gearbox enclosure structure itself. The enclosure walls are designed with thermal conductivity properties that allow them to act as heat sinks, eliminating the need for separate external heat exchangers and fluid conduits. This integration removes the leakage risk associated with external cooling systems while maintaining effective heat removal from the transmission.
Solution Approach 2:
The patent extracts the fluid conduit system from the cooling mechanism. Instead of using liquid coolant through conduits, the design relies on direct thermal conduction through the enclosure walls to ambient air or mounting structures, removing the intermediary fluid medium that could leak and eliminating the associated reliability concerns.
2Temperature
If an external heat exchanger with fluid conduits is implemented, then heat removal capability is improved, but device complexity and weight increase
Solution Approach 1:
The thermal management function is merged into the structural enclosure itself. The gearbox housing serves dual purposes: containing the mechanical components and dissipating heat through its walls. This eliminates the need for separate heat exchanger components, fluid conduits, pumps, and associated mounting hardware, significantly reducing device complexity.
Solution Approach 2:
The enclosure structure performs multiple functions simultaneously: mechanical containment of gears and bearings, structural support, and thermal dissipation. This multi-functionality eliminates the need for dedicated heat exchanger components and fluid transport systems, reducing overall system complexity and component count.
3Strength
If traditional load-bearing structures are used in addition to the gearbox enclosure, then structural strength is improved, but weight increases
Solution Approach 1:
The gearbox enclosure is designed to serve dual purposes: housing the transmission components and providing load-bearing structural support for the aircraft. The enclosure walls are engineered with appropriate thickness and material properties to withstand aerodynamic loads and vibrations, eliminating the need for separate structural bracing or support structures and thereby reducing overall weight.
Solution Approach 2:
The structural support function is merged with the enclosure housing. Instead of having separate load-bearing frames or bracing in addition to the gearbox case, the case itself is designed as the primary structural element that attaches to and supports the aircraft rotor system, reducing redundant structural materials and weight.
4Device complexity
If the gearbox enclosure provides both heat dissipation and load-bearing functions, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs composite material construction for the gearbox enclosure, combining materials with optimized thermal and mechanical properties. This allows the single enclosure structure to simultaneously achieve both heat dissipation and load-bearing requirements through material selection rather than complex geometric features, reducing manufacturing precision requirements while maintaining dual 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 gearbox enclosure effectively removes heat from lubricants and supports structural loads, reducing the need for external heat exchangers and load-bearing structures, enhancing aircraft efficiency and safety by minimizing weight and fluid leakage risks.
Implementation Method 1
a variable porosity region disposed between the external liner and the internal liner. The variable porosity region may be configured for a lubricant to flow therethrough
Implementation Method 2
the variable porosity region may operate to remove substantially all of the heat energy of the lubricant as the lubricant passes between a lubricant input port and a lubricant output port of the gearbox enclosure
Implementation Method 3
the variable porosity region of the gearbox enclosure may comprise a lattice region comprising a porosity of between about 5.0% and about 85.0%. At least a portion of a gearbox enclosure may be configured to support a load of between about 1380.0 N/cm2 and about 124,200.0 N/cm2
Data Source
AI summary
Briefly, the disclosure relates to apparatuses and methods to form a gearbox enclosure comprising an external liner, an internal liner, and a variable porosity region disposed between the external liner and the internal liner. The variable porosity region may be configured to accommodate flow of the lubricant, thereby providing a capability to cool, for example, a lubricating fluid at an elevated temperature.