Spigot Load Transfer Interface for Compressor Scroll Housing
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Solution Overview
Problem
In aircraft engines with centrifugal impellers housed in scroll housings, the asymmetrical outer walls of the scroll housings lead to inconsistent load distribution, making it challenging to transfer loads effectively from the engine shaft to the engine casing.
Innovation Solution
A load transfer interface is introduced, comprising a first component with a spigot extending axially from an annular body and a second component with a spigot-receiving cavity, where the spigot-receiving cavity is positioned radially inwardly of the asymmetrically shaped outer wall, allowing for consistent load transfer from the bearing housing to the engine casing through an axisymmetric path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If loads are transferred through the asymmetrically shaped outer wall of the scroll housing, then the load transfer path is established, but the load distribution becomes inconsistent
Solution Approach 1:
The invention extracts the load transfer function from the asymmetrically shaped outer wall by introducing a dedicated axisymmetric spigot structure. The spigot is decoupled from the asymmetric scroll housing geometry, allowing load transfer to occur through a separate, symmetric load transfer path that ensures consistent load distribution while the asymmetric outer wall maintains its aerodynamic function
Solution Approach 2:
The spigot acts as an intermediary component between the scroll housing and the engine casing. It provides a dedicated load transfer interface that mediates the load transfer process, ensuring symmetric and consistent load distribution while allowing the asymmetric outer wall to maintain its structural and aerodynamic role
2Strength
If the scroll housing uses asymmetrically shaped outer walls for structural integrity, then the housing can contain the centrifugal impeller, but the material requirements increase leading to heavier design
Solution Approach 1:
The invention extracts the load transfer function from the asymmetric outer wall structure, allowing the outer wall to be optimized for its primary function of containing the centrifugal impeller and maintaining aerodynamic shape, rather than being over-designed for load transfer. This separation of functions reduces material requirements and weight
Solution Approach 2:
The invention applies local quality by introducing the spigot structure at specific locations where load transfer is needed, rather than reinforcing the entire asymmetric outer wall. The spigot provides localized load transfer capability with minimal material, while the rest of the outer wall maintains its asymmetric geometry for aerodynamic purposes
Data Source
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AI summary
There is provided a load transfer interface in an aircraft engine for transferring a load from a bearing housing (46) to an engine casing (32; 34). The load transfer interface comprises: a scroll coverplate (30) configured to be operatively coupled to and receive the load from a bearing housing (46), the scroll coverplate (30) having a first annular body (66) with a spigot (64; 64') extending axially from the first annular body (66) relative to a central engine axis (11); and a scroll housing (26) operatively coupled to the scroll coverplate (30) and configured to be operatively coupled to an engine casing (32; 34), the scroll housing (26) having a second annular body (70) with a spigot-receiving cavity (68; 68') disposed therein, the spigot-receiving cavity (68;68') shaped and positioned to receive the spigot (64; 64') of the scroll coverplate (30), the scroll housing (26) configured to receive the load from the scroll coverplate (30) and transfer the load to the engine casing (32; 34), the scroll housing (26) including a radially outer wall (28) that is asymmetrically-shaped about a circumference of the second annular body (70), the spigot-receiving cavity (68; 68') disposed radially inwardly of the radially outer wall (28), and wherein an axial width of a radially outer scroll area (44) defined by the radially outer wall (28) varies along a circumference of the scroll housing (26).