Piston Rod Friction Welding With Shielded Flash Chamber Sealing
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Solution Overview
Problem
Existing methods for manufacturing piston and piston rod assemblies often result in contamination or damage to seal assemblies due to the sequence of welding operations, making it difficult to achieve a clean weld of the piston to the piston rod while maintaining the integrity of the seal assembly.
Innovation Solution
A method involving friction welding, where the piston is welded to the piston rod with a flash portion and chamber design, allowing for a clean welding step after the seal assembly is placed, and the joint area is shielded within the flash chamber, preventing external interference and contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If welding operations are performed before placing the seal assembly, then the welding can be completed without interference, but the seal assembly becomes contaminated or damaged by welding particles
Solution Approach 1:
The seal assembly is placed around the piston rod before the welding operation between the piston and piston rod. This preliminary placement allows the seal to be positioned in a clean environment before welding particles are generated, preventing contamination while maintaining production efficiency.
Solution Approach 2:
The piston rod acts as an intermediary element that allows the seal assembly to be positioned between the welding zone and the final assembly. By placing the seal on the piston rod before welding, the piston rod serves as a carrier that protects the seal from direct exposure to welding particles.
2Reliability
If the seal assembly is placed before welding operations, then contamination to the seal is prevented, but the welding operation becomes more complex due to the presence of the seal
Solution Approach 1:
The welding operation is segmented into two independent steps: first welding the rod head to the piston rod, then welding the piston to the piston rod. The seal assembly is placed on the piston rod between these steps, allowing each welding operation to proceed separately without the seal interfering with the welding process.
Solution Approach 2:
The piston rod serves as a dynamic carrier that holds the seal assembly during the welding process. The seal can be positioned and secured on the piston rod, allowing the welding operation to proceed around it without requiring permanent fixation or complex positioning mechanisms.
3Manufacturing precision
If the piston is welded to the piston rod after the seal assembly is placed, then a clean weld is achieved, but the welding must be performed in a specific sequence that increases manufacturing time
Solution Approach 1:
The seal assembly is preliminarily placed on the piston rod before the piston welding operation. This allows the welding to be performed cleanly without requiring additional cleaning steps or rework, maintaining manufacturing efficiency while ensuring weld quality.
Solution Approach 2:
The manufacturing process maintains continuity by placing the seal assembly and performing the piston welding in a continuous sequence without interrupting the production flow. The seal placement and welding operations are integrated into a single manufacturing cycle, minimizing idle time.
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 ensures a strong, clean weld of both the piston and piston rod assembly, reducing the risk of contamination and damage to the seal assembly, and enhances mechanical strength, suitable for heavy-duty applications.
Implementation Method 1
friction welding the piston rod to the piston by causing a relative rotation and an axial pressure in between the flash surface of the piston rod and chamber bottom of the piston such that the flash surface joins to the chamber bottom
Data Source
Figure 1~2
Figure 3A~3B
Figure 3C~4
AI summary
A piston and piston rod assembly for a linear actuator is manufactured by a friction welding method. The piston rod comprises a flash portion formed by a narrowed portion with a flash surface formed by an end face. The piston comprises a flash chamber formed by a centrally positioned recess. In the friction welding method the flash portion is inserted into the flash chamber and a relative rotation and an axial pressure in between the piston rod and the piston is carried out such that the flash surface joins to the chamber bottom. Advantageously, a clean welding step is provided which step allows a prior placement of a seal assembly around the piston rod. The seal assembly including a wiper, seal ring and a gland can be placed around the piston rod before the clean welding step is carried out.