Integral Centering Spring with Fluid Damping Cavity
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Solution Overview
Problem
Conventional centering springs in gas turbine engines are costly and complex due to tight tolerances and short lengths, leading to reduced fatigue life and increased stress, which complicates assembly and maintenance within small bearing compartments.
Innovation Solution
A centering spring design featuring an annular flange and body with resilient members that form damping cavities, allowing for a longer axial length and reduced bending stresses, integrating bearing support and fluid delivery functions into a single component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If conventional centering springs are used with short axial length to fit small bearing compartments, then the geometric constraints are satisfied, but the bending stresses increase and fatigue life decreases
Solution Approach 1:
The centering spring design transitions from a conventional short axial configuration to an extended radial configuration. The resilient members extend radially outward from the bearing support, allowing the spring to achieve sufficient length for acceptable stress levels in the radial dimension rather than being constrained axially. This dimensional change enables the spring to fit within small bearing compartments while maintaining adequate length for fatigue resistance.
2Device complexity
If conventional centering springs with multiple parts and tightly-toleranced interfaces are used, then the geometric constraints are satisfied, but the manufacturing cost and complexity increase
Solution Approach 1:
The invention merges multiple conventional components into a single integrated centering spring structure. The resilient members are directly formed as part of the centering spring body, eliminating the need for separate bearing supports, retaining features, and multiple fastening components. This consolidation reduces the number of parts and interfaces, simplifying manufacturing and reducing costs while maintaining the necessary geometric constraints within small bearing compartments.
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 enhances fatigue life and reduces complexity by minimizing bending stresses and the number of components, enabling more efficient assembly and maintenance while maintaining geometric constraints.
Implementation Method 1
a deflection of the body relative to the flange is restrained by a restoring force produced by the resilient member
Implementation Method 2
the outer race is shaped to form an annular cavity between the outer race and the bearing support, which forms a squeeze film damper (SFD) when filled with a damping fluid. With this configuration, radial displacement of the outer race relative to the bearing support is restrained by squeeze film pressure.
Data Source
Figure 1
Figure 2
AI summary
An assembly includes a centering spring (22) having an annular flange (24), an annular body (26), and a plurality of resilient beams (29) extending from the flange to the body. The annular flange defines a passage (80) that extends at least radially inward with respect to a centerline (12) circumscribed by the flange from a radially outer surface (34) of the flange to a radially inner surface (42) of the flange. The annular body is spaced from the flange along the centerline, a radially outer surface (62) of the body forming a first annular cavity (20) relative to an adjacent surface configured to be a first fluid damper. A deflection of the body relative to the flange is restrained by a restoring force produced by the plurality of resilient beams and the first fluid damper. A method includes providing the aforementioned assembly and passing a damping fluid through the passage of the flange.