Friction-Welded Piston Assembly With Weld Bead Deflection
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Solution Overview
Problem
Friction welding of piston parts often results in a weld bead forming in regions that need to remain clear for connecting rod movement, leading to mechanical contact and interference.
Innovation Solution
A deflecting device is integrated into the friction welding process to deflect the weld bead, ensuring it does not interfere with the connecting rod's movement by being in abutting contact and positioned to avoid contact with the connecting rod after assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If friction welding is used to join piston upper part and piston lower part, then the joining strength is improved, but the weld bead forms in regions that obstruct connecting rod movement
Solution Approach 1:
A deflecting device is introduced as an intermediary element during the friction welding process. This device actively redirects the weld bead away from the harmful region (inner shape below piston recess) to a safe location, allowing the welding process to proceed while preventing obstruction of connecting rod movement.
Solution Approach 2:
The deflecting device is positioned and configured before the friction welding process begins. By pre-establishing the deflection path, the weld bead is guided away from critical areas during the welding operation, preventing the formation of obstructions in advance rather than requiring post-processing.
2Ease of manufacture
If weld bead is formed in the inner shape below piston recess, then the friction welding process is simplified, but clearances for connecting rod movement are reduced
Solution Approach 1:
The deflecting device serves as a temporary intermediary tool that modifies the weld bead trajectory during manufacturing. It enables the welding process to maintain its simplicity while actively managing the weld bead placement to preserve necessary clearances for connecting rod operation.
Solution Approach 2:
The deflecting device applies a localized effect only to the weld bead material, redirecting it to specific safe zones without affecting the overall welding process or the properties of the piston components being joined. This selective intervention preserves clearances in critical areas.
3Length of moving object
If deflecting device is added to redirect weld bead, then clearance for connecting rod movement is maintained, but device complexity increases
Solution Approach 1:
The deflecting device is designed as a dedicated intermediary component with a specific function (redirecting weld bead). By isolating this function to a separate, relatively simple device, the complexity is contained and does not propagate to the entire welding system or require complex integration with the piston components.
Solution Approach 2:
The welding system is segmented into functional components: the friction welding mechanism, the clamping device, and the deflecting device. This segmentation allows the deflecting device to be optimized for its specific purpose of weld bead redirection without complicating the overall welding process or requiring redesign of other system components.
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 prevents the weld bead from obstructing the connecting rod's movement, maintaining necessary clearances and avoiding mechanical contact, thus ensuring smooth operation and reducing the need for post-processing adjustments.
Implementation Method 1
the piston upper part and the piston lower part are joined to one another by means of friction welding
Data Source
AI summary
A method for producing a piston for an internal combustion engine may include arranging a piston upper part and a piston lower part in a friction welding device. The piston upper part may include a piston head with a combustion recess. The piston lower part may include two mutually opposite skirt elements connected to one another via two mutually opposite pin bosses. The method may also include arranging a deflecting device configured to deflect at least one weld bead one of on and in the friction welding device. The method may further include joining the piston upper part and the piston lower part to one another via friction welding.