Friction Welding Piston Rod Boring Process
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Solution Overview
Problem
The existing piston rod manufacturing methods using friction welding often result in stress concentration at the joining face due to beads formed on the inner circumference, leading to potential fractures and reduced durability.
Innovation Solution
A piston rod manufacturing method that involves friction welding the rod main body and rod head, followed by a boring process to remove center segregation impurities through a hole penetrating the joining face, eliminating the bead and stress concentration, and allowing for the use of lower-quality materials to reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the respective end surfaces of the rod main body and the rod head are hollowed out before friction welding to remove impurities, then the joint strength is improved, but beads are formed on the inner circumferential side of the joining face which cannot be removed after welding, causing stress concentration and potential fracture
Solution Approach 1:
Instead of hollowing out the axial center portions before friction welding as in conventional methods, this invention performs friction welding first on the solid rod main body and rod head, then hollows out the axial center portions after welding. This inversion of the process sequence allows the beads formed during welding to be removed during the subsequent hollowing out operation, eliminating stress concentration points while maintaining the benefit of impurity removal for joint strength.
2Manufacturing precision
If hollowing out is performed before friction welding, then impurities are removed from the axial center portion, but the process complexity increases and manufacturing efficiency decreases
Solution Approach 1:
This invention merges two operations into one: the hollowing out process simultaneously removes both the beads formed during friction welding and the impurities caused by center segregation. By combining these removal functions into a single post-welding hollowing out operation, the process complexity is reduced compared to performing hollowing out before welding, while achieving both bead removal and impurity elimination.
3Manufacturing precision
If hollowing out is performed before friction welding, then impurities are removed, but manufacturing time increases
Solution Approach 1:
By inverting the process sequence to perform friction welding before hollowing out, this invention eliminates the need for a separate pre-welding hollowing out operation. The single post-welding hollowing out operation serves dual purposes: removing beads and removing impurities. This reduces the total number of operations and manufacturing time compared to conventional methods that require hollowing out before welding.
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 method enhances the durability of the joined body by removing center segregation impurities, preventing fractures, and enabling the use of less expensive materials, while also facilitating effective quality inspections without detecting hollow spaces as defects.
Implementation Method 1
a rod main body 2 and a rod head 3 are joined by friction welding
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A piston rod manufacturing method of manufacturing a piston rod by joining a solid rod main body and a solid rod head includes a first step of joining respective end surfaces of the rod main body and the rod head by friction welding; and a second step of performing boring process on an axial center portion from the rod head side so as to penetrate through a joining face between the rod main body and the rod head.