Retention Pin Melt Jointing for Gas Turbine Reliability
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Solution Overview
Problem
Traditional mechanical fasteners like rivets lack controlled material strength and structural integrity, leading to potential damage in high-stress or high-temperature environments, such as gas turbine engines, due to operator variability and the risk of rivet heads being liberated.
Innovation Solution
A retention pin assembly is formed by melting a pin into a pocket without creating a metallurgical joint, allowing the pin to rotate freely and be easily removable, using a welder to fill a countersink or bore-like pocket with molten metal that quickly cools and is ground flush, ensuring the pin's fatigue properties match solution heat-treated material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional rivet fasteners are used, then ease of manufacture is improved, but reliability deteriorates due to uncontrolled material strength and risk of rivet head liberation
Solution Approach 1:
The patent replaces the traditional mechanical rivet forming system with a melting-based joining system. Instead of mechanically deforming rivet material, the invention uses localized melting of the pin material to create a controlled joint, substituting mechanical action with thermal action to achieve both ease of manufacture and improved reliability
Solution Approach 2:
The invention changes the physical state of the pin material from solid to liquid and back to solid through controlled melting and cooling. This parameter change allows the material to flow into the pocket and create a reliable joint while maintaining control over the joining process, resolving the contradiction between ease of manufacture and reliability
2Ease of operation
If rivet constructs are used, then ease of operation is improved, but harmful factors increase due to rivet heads being liberated into engines
Solution Approach 1:
The invention extracts the problematic rivet head from the fastener system. By melting the pin material into the pocket without forming a traditional rivet head, the design eliminates the component that could be liberated and cause damage, while maintaining the ease of operation through simple installation and removal processes
Solution Approach 2:
The invention converts the potential harm of material liberation into a benefit by directing the molten material into the pocket where it solidifies to form a secure joint. The melting process, which could potentially cause damage, is instead used to create a reliable connection that prevents harmful liberation
3Reliability
If melt forming is used, then reliability is improved through controlled material strength, but manufacturing precision requirements increase
Solution Approach 1:
The invention applies preliminary action by pre-forming the pocket with specific geometric characteristics before the melting process. The pocket is designed with controlled dimensions and surface features that guide the molten material, ensuring reliable joint formation without requiring extreme precision during the melting operation itself
Solution Approach 2:
The invention utilizes the phase transition of the pin material from solid to liquid and back to solid to achieve reliable joining. The controlled melting and solidification process allows the material to adapt to the pocket geometry, reducing the stringency of manufacturing precision requirements while maintaining joint reliability
4Ease of manufacture
If traditional fasteners are used, then ease of manufacture is improved, but fatigue properties deteriorate due to overworking and uncontrolled material strength
Solution Approach 1:
The invention replaces mechanical forming with thermal processing to preserve fatigue properties. By using localized melting instead of mechanical deformation, the grain structure and material properties are maintained without the damaging effects of overworking, achieving both ease of manufacture and improved fatigue resistance
Solution Approach 2:
The invention changes the processing parameter from mechanical force to thermal energy, allowing the pin material to be joined without subjecting it to the high stresses that cause fatigue degradation. This parameter change enables easy manufacturing while preserving the material's fatigue properties
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 solution provides a reliable, customizable mechanical joint with improved fatigue properties and ease of removal, eliminating the risks associated with traditional rivets and allowing for use in sensitive environments like gas turbine engines without damaging the underlying components.
Implementation Method 1
The welder can watch the molten metal flow into the pocket
Implementation Method 2
The molten pin metal immediately cools to fill the pocket
Data Source
AI summary
An improved retention pin assembly and method of forming a pin assembly that uses a melt in a pocket without a metallurgical joint having been formed. The assembly can be generated by a method of forming a joint which includes providing a metal shaft and a member that is operable to receive the shaft. A pocket is formed within the member which operates to receive a melt pool. Next the shaft is inserted into apertures in the member. A welding or melting operation is then performed to create a melted portion that occupies the pocket. A joint is created using a retention pin.