Adjustable Oil Channel Mount for Gas Turbine Gear Drive
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Solution Overview
Problem
The differences in thermal expansion between aluminum oil channels and titanium alloy bearing support housings in gas turbine engines pose challenges at the mount interface, leading to potential misalignment and wear during operation.
Innovation Solution
The use of elongated connecting members with slots in the oil channel and bearing support, along with inserts and a Belleville spring washer, allows for radial adjustment and compensation for thermal expansion differences, ensuring secure mounting and efficient oil collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If aluminum material is used for the oil channel to reduce weight, then the weight of the oil channel is reduced, but thermal expansion differences cause misalignment and wear at the mount interface
Solution Approach 1:
The mounting system transitions from a rigid fixed connection to a dynamic adjustable connection. The oil channel is mounted on support blocks with adjustable positioning mechanisms that allow real-time compensation for thermal expansion differences between the aluminum oil channel and titanium bearing support housing, maintaining reliable mounting despite material differences.
Solution Approach 2:
Support blocks serve as intermediary elements between the aluminum oil channel and the titanium bearing support housing. These intermediaries provide a compliant mounting interface that accommodates differential thermal expansion, preventing direct contact and potential wear between the dissimilar materials while maintaining structural support.
2Stability of the object's composition
If fixed mounting is used to ensure stable oil channel position, then positioning stability is improved, but thermal expansion causes misalignment and wear
Solution Approach 1:
The mounting system incorporates dynamic adjustment capabilities through support blocks with adjustable positioning mechanisms. This allows the oil channel position to be maintained stably while accommodating thermal expansion movements, converting a static rigid connection into a dynamic system that adapts to thermal conditions.
Solution Approach 2:
The support blocks are designed with built-in compliance features and adjustment capabilities that anticipate thermal expansion effects. This beforehand cushioning allows the mounting system to absorb and compensate for thermal expansion differences before they cause misalignment or wear, protecting the interface from harmful effects.
3Strength
If rigid connection is used between oil channel and bearing support, then structural strength is improved, but differential thermal expansion causes wear at the interface
Solution Approach 1:
Support blocks act as intermediary elements between the oil channel and bearing support housing, providing a compliant interface that maintains mounting strength while preventing direct rigid contact. This intermediary layer absorbs differential thermal expansion, eliminating the wear mechanism that would occur in a direct rigid connection between dissimilar materials.
Solution Approach 2:
The mounting system incorporates flexible or compliant elements in the support blocks that allow for thermal expansion accommodation. These flexible components maintain structural strength while permitting the differential movement between aluminum and titanium parts, preventing interface wear through controlled compliance rather than rigid constraint.
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 solution effectively mitigates thermal expansion issues, maintaining the oil channel's concentricity with the fan drive gear system, preventing wear and ensuring efficient oil removal while accommodating differential expansion rates.
Implementation Method 1
a Belleville spring washer sits between a head of the connecting members and the oil channel, with the Belleville washer urging the oil channel toward the bearing support to compensate for any wear during operation
Implementation Method 2
Differences in thermal expansion between the aluminium and the titanium alloy have raised challenges at a mount interface
Data Source
AI summary
A turbine is operably connected to drive a compressor, and to drive a fan through a gear drive. A number of intermediate gears connecting an output shaft of the turbine to a fan drive shaft for the fan. An oil channel collects oil thrown outwardly of the gear drive. A bearing support mounts bearings supporting the fan drive shaft. The oil channel and the bearing support each include mating faces that are bolted together by a plurality of bolts. The bolts extend through oil channel holes in the mating face of the oil channel. The oil channel holes have one dimension which closely receives the bolts and another dimension which is larger than an outer diameter of the extending portion of the bolts, such that the bolts may adjust radially within the oil channel holes.