Interlocking Joint Assembly for Thermal-Cycling Engine Connections
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Solution Overview
Problem
Conventional nut and bolt configurations in gas turbine engines face thermal cycling issues, leading to bolt seizure and increased assembly time, weight, and aerodynamic disruptions, while existing joint solutions suffer from radial movement and require complex arrangements.
Innovation Solution
A joint assembly featuring a connection member insertable into a cavity formed by concavities on opposing surfaces, with a protrusion and recess arrangement to prevent axial and radial separation, using a resilient retaining member to interlock components, allowing for secure assembly and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional nut and bolt configurations are used to secure engine components, then the components can be firmly joined, but the bolts tend to gall and seize due to thermal cycling, requiring expensive and time-consuming drilling out during disassembly
Solution Approach 1:
The joint assembly is divided into a connection member and a retaining member as separate functional elements. The connection member provides the joining function while the retaining member prevents axial movement, allowing for easier disassembly by addressing each function independently and avoiding the seizure issues that affect conventional bolts under thermal cycling
Solution Approach 2:
The retaining member is designed to prevent axial movement of the connection member before thermal cycling can cause galling or seizure. By pre-preventing axial displacement, the system eliminates the conditions that lead to bolt seizure during thermal operation, making future disassembly easier
2Strength
If nuts and bolts are used to join components, then secure connection is achieved, but suitable flanges must be provided on the parts which adds to weight and increases assembly time
Solution Approach 1:
The connection member and retaining member functions are merged into a single integrated joint assembly that can be inserted through a slot in the outer surface of the assembled components. This eliminates the need for separate flanges and multiple fastening operations, reducing both weight and assembly complexity while maintaining secure connection
Solution Approach 2:
The joint assembly serves multiple functions: the connection member provides the joining function while the retaining member prevents axial movement. This multi-functional design replaces the need for separate flanges and bolts, simplifying the overall structure and reducing assembly steps
3Strength
If bolts heads are positioned in the gas flow path to secure components, then the components are firmly joined, but the aerodynamics of the engine is disrupted and the bolt deterioration is accelerated
Solution Approach 1:
The joint assembly is designed to be inserted through a slot in the outer surface of the assembled components, positioning the connection member within the cavity between components rather than in the gas flow path. This extracts the fastening function from the aerodynamic flow path, eliminating aerodynamic disruption while maintaining joint strength
Solution Approach 2:
The slot in the outer surface serves as an intermediary pathway that allows the joint assembly to be installed without exposing bolt heads to the gas flow. The connection member is mediated through this slot into a protected position within the component cavity, shielding it from aerodynamic harmful effects
4Strength
If a wire is used as a close fit in the annular cavity to securely hold components together, then axial separation is prevented, but unwanted radial movement occurs between the opposing faces of the joint
Solution Approach 1:
The joint assembly segments the holding function (connection member in the cavity) from the radial stabilization function (retaining member preventing axial movement of the connection member). This segmentation allows each element to optimize its specific function without compromising the other, preventing both axial separation and radial movement
5Stability of the object's composition
If corresponding angularly offset joint faces with two wires are used to provide additional strength against radial movement, then radial stability is improved, but the device complexity and assembly difficulty increase
Solution Approach 1:
The connection member and retaining member are merged into a single integrated assembly that provides both axial holding and radial stabilization functions. This merging eliminates the need for two separate wires with angularly offset joint faces, reducing structural complexity while maintaining both axial and radial stability
Solution Approach 2:
The joint assembly serves as a universal solution that simultaneously provides axial holding strength through the connection member in the cavity and radial stability through the retaining member preventing axial movement. This multi-functional design replaces the complex two-wire arrangement with a single integrated component
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 joint assembly provides a secure, lightweight, and aerodynamically efficient connection that accommodates thermal expansion, reducing assembly time and minimizing radial movement, while allowing for easier maintenance and reduced weight.
Implementation Method 1
a connection member insertable into the cavity at the interface to prevent axial separation of the first and second components
Implementation Method 2
The free end may be axially insertable into the recess so as to prevent relative movement between the first and second component in a radial direction
Data Source
AI summary
A joint assembly joins first and second components about a common axis. The first component has a first end portion having a radially outwardly facing surface shaped to fit radially inside a second surface of a hollow second end portion of the second component to form an interface between the opposing first and second surfaces. The first and second surfaces have a concavity extending laterally with respect to the axis such that when the first and second surfaces are opposingly arranged the opposing concavities define a cavity at the interface. A retaining member is insertable into the cavity at the interface to prevent axial separation of the first and second components. One of the first and second end portions has a free end protrusion axially spaced from the concavity and the other of the first and second end portions has an axially extending recess arranged to receive the free end.