Input Shaft Contact Seal Assembly for Bearing Heat Damage
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Solution Overview
Problem
Variable frequency generators in aerospace applications experience damage due to heat generated by frictional engagement between fixed and rotating surfaces, leading to damage in bearings and drive shafts, necessitating a more reliable sealing interface than the existing hydrodynamic input seal.
Innovation Solution
A contact sealing assembly is introduced, comprising a support structure, bearing assembly, and input seal with a face plate anti-rotation pin and sealing elements like O-rings, which directly contacts the input shaft and bearing assembly, forming a reliable seal and reducing the risk of oil leakage and debris ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydrodynamic input seal is used to seal the input shaft bearing, then the sealing function is provided, but heat generated by frictional engagement damages the bearings and drive shaft
Solution Approach 1:
The patent extracts the sealing function from the hydrodynamic seal that was causing frictional heat and transfers it to a contact seal assembly. The contact seal assembly includes a seal housing, seal plate, and sealing elements that provide sealing without the frictional engagement problems of the hydrodynamic seal, thereby removing the harmful thermal effect while preserving the necessary sealing function.
Solution Approach 2:
The contact seal assembly acts as an intermediary between the input shaft and the bearing seal cavity. It provides a sealing interface that prevents oil leakage and debris ingress without creating the frictional heat that damaged the bearings and drive shafts in the previous hydrodynamic seal design.
2Reliability
If a contact sealing assembly is introduced to prevent frictional heat damage, then reliability improves, but device complexity increases
Solution Approach 1:
The contact seal assembly is segmented into distinct functional components: a seal housing that provides structural support and mounting, a seal plate that forms the sealing surface, and sealing elements (such as O-rings or lip seals) that provide the actual sealing function. This segmentation allows each component to be optimized for its specific function and facilitates easier manufacturing, assembly, and maintenance.
Solution Approach 2:
The contact seal assembly is designed to perform multiple functions: sealing the bearing cavity, preventing oil leakage, blocking debris ingress, and providing structural support for the bearing assembly. By consolidating these functions into a single integrated assembly, the patent reduces overall system complexity compared to having separate components for each function.
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 contact sealing assembly effectively prevents damage from frictional heat, offering improved reliability and cost-effectiveness, suitable for both new and existing variable frequency generators, and maintains proper operation during decoupling scenarios.
Implementation Method 1
heat created by the frictional engagement between a fixed and rotating surface associated with an input shaft
Data Source
AI summary
A sealing assembly of an input shaft includes a support structure, a bearing assembly, and an input seal. The input seal including an input seal housing having a first portion and a second portion. The first portion is arranged adjacent the bearing assembly. At least one face plate anti-rotation pin is coupled to the input seal housing and positioned adjacent the input shaft. A face plate is positioned adjacent the second portion. The face plate is configured to directly contact the input shaft.