Thrust Bearing Shaft Airflow Segmentation for Cooling
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Solution Overview
Problem
Existing thrust bearing designs in aircraft compressor systems suffer from insufficient cross-sectional flow area, leading to inadequate airflow and potential inefficiencies in cooling and operation.
Innovation Solution
The thrust bearing shaft features an enlarged disk with a first cylindrical portion and a second cylindrical portion of smaller diameter, along with a hollow bore containing a ledge with a central hole and twelve air holes, providing increased airflow passages and ensuring adequate flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a conventional thrust bearing shaft design is used, then the structure is simple, but the cross-sectional flow area is insufficient leading to inadequate airflow
Solution Approach 1:
The shaft is divided into multiple functional sections: a first cylindrical portion with outer air holes for external airflow, a second cylindrical portion with inner air holes for internal airflow, and a disk portion with thrust bearing surfaces. This segmentation allows independent optimization of airflow paths and increases total flow area without creating a monolithic complex structure.
Solution Approach 2:
The invention transitions from a simple cylindrical shaft to a multi-dimensional structure by adding a disk portion with thrust bearing surfaces and creating both outer and inner airflow passages. This dimensional expansion provides additional flow paths and increases the effective cross-sectional area for air cooling without proportionally increasing structural complexity.
2Quantity of substance
If the ledge cross-sectional area is increased to improve airflow, then airflow adequacy is achieved, but the manufacturing complexity increases
Solution Approach 1:
The air cooling holes are segmented into two distinct groups: outer air cooling holes in the first cylindrical portion and inner air cooling holes in the second cylindrical portion. This segmentation allows each group to be optimized independently for its specific airflow function while simplifying the overall manufacturing process compared to creating a single complex high-area passage.
Solution Approach 2:
Different regions of the shaft are given different qualities: the first cylindrical portion has outer air holes for external cooling, the second cylindrical portion has inner air holes for internal cooling, and the disk has thrust bearing surfaces. This local differentiation optimizes airflow in each region without requiring a uniformly complex structure throughout, improving manufacturability.
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 enhanced airflow passages improve airflow efficiency, ensuring sufficient air flow and operational stability in the compressor system.
Implementation Method 1
cooling air is brought into a bearing cooling inlet. The cooling air passes along thrust bearing surfaces, and then may pass between the shaft and various housing portions
Implementation Method 2
Air passes through the air passages, with a portion on a rear side of the disk passing into an interior bore of the thrust shaft
Data Source
AI summary
A thrust bearing shaft has an enlarged disk at one axial end to provide a rotating surface in a thrust bearing. A first cylindrical portion extends from the disk. A second cylindrical portion has a smaller diameter than the first cylindrical portion and extends from the first cylindrical portion to an end of the thrust shaft remote from the disk. The thrust shaft has a hollow bore with a ledge extending across the bore at a location within the first cylindrical portion. The ledge is formed with a central hole of a first hole diameter, and twelve air holes spaced circumferentially about the central hole. The twelve holes are formed of a second hole diameter, with a ratio of the first hole diameter to the second hole diameter being between 2.55 and 2.71. In addition, a bearing assembly, a compressor, and a method of assembling a compressor are disclosed.