Turbomachine Shaft Centering With Directional Bearing Stiffness
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Solution Overview
Problem
Existing flexible cages for aircraft turbomachine shafts have uniform stiffness in all transverse directions, failing to adapt to different stress directions, which can lead to instability and performance degradation.
Innovation Solution
A centering and guiding device with flexible columns having ends engaged with or without play in orifices, providing different stiffnesses in two perpendicular directions, allowing for tailored flexibility based on stress orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a shaft is supported by two parallel support blocks during assembly, then the shaft can be positioned, but it is difficult to ensure accurate centring and guidance of the shaft
Solution Approach 1:
A centring device is introduced as an intermediary component between the shaft and the support blocks. This device includes a centring element that fits into a corresponding recess in the shaft, providing a precise mechanical interface that ensures accurate centring and guidance of the shaft during assembly operations.
Solution Approach 2:
The patent replaces the simple mechanical support block system with a more sophisticated centring mechanism that uses a centring device with specific geometric features (centring element and recess) to achieve precise positioning, substituting crude mechanical support with a dedicated centring system.
2Manufacturing precision
If conventional support blocks are used, then the structure is simple, but the shaft cannot be accurately centred and guided
Solution Approach 1:
The support structure is segmented into distinct functional components: support blocks for basic positioning and a separate centring device with a centring element for precise alignment. This segmentation allows each component to be manufactured independently and then assembled together to achieve the required precision.
Solution Approach 2:
The centring device is designed to be installed beforehand on the support blocks, creating a pre-assembled centring system that automatically guides the shaft into correct position during assembly, eliminating the need for complex post-assembly adjustments.
Data Source
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AI summary
Disclosed is a device for centring and guiding a shaft of an aircraft turbine engine, said device comprising: an outer ring (12) of a rolling bearing (14), extending about an axis and comprising orifices (42a, 42b), an annular bearing support (16) extending about the axis and at least partially about the ring, said support comprising orifices (44a, 44b) and a series of studs (40, 41) for connecting the ring to the support, said studs being distributed about the axis and extending parallel to said axis; the device being characterised in that ends of first studs (40) are engaged without clearance in said orifices (42a, 44a), and ends of second studs (41) are engaged with clearances in said orifices (42b, 44b) of the ring and/or of the support, said clearances being configured so that the device has different stiffnesses in at least two directions perpendicular to said axis.