Rod Guide Assembly Repair Using Electron Beam Seat Welding
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Solution Overview
Problem
The maintenance of aircraft engine fuel control units often requires the destruction and replacement of rod guide assemblies, leading to wastefulness and high costs, as existing methods do not allow for the reuse of components like the spring seat and rod after maintenance.
Innovation Solution
A method involving electron beam welding with a circular beam deflection pattern is used to securely attach a replacement spring seat to the existing rod of the rod guide assembly, allowing for the reuse of components, along with a fixture to hold the assembly in alignment during welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional welding methods are used to attach spring seat to rod, then the assembly can be maintained, but the components cannot be reused and full replacement is required
Solution Approach 1:
The patent extracts the spring seat from the rod assembly during maintenance, allowing it to be inspected, cleaned, and reused on a different rod. This separation enables component reuse rather than requiring complete assembly replacement, directly addressing the loss of substance issue.
Solution Approach 2:
The patent replaces conventional welding methods with electron beam welding to attach the spring seat to the rod. This substitution provides precise, localized welding capability that enables component reuse while maintaining assembly integrity, resolving the contradiction between manufacturability and component reusability.
2Manufacturing precision
If electron beam welding is used with circular beam deflection pattern, then precise welding is achieved enabling component reuse, but the device complexity increases
Solution Approach 1:
The patent employs a circular beam deflection pattern in the electron beam welding process, where the beam moves in a periodic circular motion during welding. This periodic action distributes heat evenly and creates precise welds, enabling manufacturing precision while the automated nature of the periodic pattern reduces operational complexity.
Solution Approach 2:
The patent utilizes electron beam welding parameters including beam energy, circular deflection radius, and welding speed to achieve precise welding. By optimizing these parameters, the process achieves high manufacturing precision with controlled device complexity, as the advanced equipment is offset by streamlined process parameters.
3Reliability
If complete assembly replacement is performed during maintenance, then reliability is ensured, but maintenance costs increase
Solution Approach 1:
The patent segments the fuel control unit into separable components (spring seat, rod, body) that can be independently maintained. By segmenting the assembly, individual components can be inspected, cleaned, and reused rather than replacing the entire assembly, reducing maintenance costs while maintaining reliability through targeted component replacement only when necessary.
Solution Approach 2:
The patent implements a process where the spring seat and rod are separated, inspected, and recovered for reuse on subsequent assemblies. This discarding and recovering approach eliminates the need for complete assembly replacement, significantly reducing maintenance costs while ensuring reliability through systematic component inspection and selective replacement.
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 approach enables the cost-effective reuse of rod guide assembly components, reducing waste and maintenance costs by allowing the re-securing of the spring seat to the rod, thus extending the life of the assembly without the need for full replacement.
Implementation Method 1
welding a replacement spring seat to the rod by: with the rod disposed on a first side of a wall of the replacement spring seat, directing an electron beam toward the wall of the replacement spring seat from a second side of the wall opposite the first side
Data Source
AI summary
A method of repairing a rod guide assembly of a fuel control unit of an aircraft engine is provided. The method comprises disconnecting a used spring seat from the rod of the rod guide assembly and welding a replacement spring seat to the rod using an electron beam controlled using a circular beam deflection pattern.