Inclined Piston Joining Surfaces to Keep Weld Spatter Out
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Solution Overview
Problem
Weld spatter formation inside the cooling channel of a combustion engine piston is difficult to remove and can cause damage during engine operation when the weld seam ends within the cooling channel.
Innovation Solution
A piston blank design where the joining surfaces are inclined relative to the central axis, allowing a laser beam to weld without passing through the cooling channel, preventing spatter formation by directing the beam into the piston upper part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the weld seam ends inside the cooling channel, then the piston can be assembled, but weld spatter forms inside the cooling channel which is difficult to remove and can cause damage
Solution Approach 1:
The joining surface of the piston upper part is designed with an inclined tangential plane relative to the central axis, creating an asymmetric geometry. This asymmetry ensures that the laser beam, when oriented in the tangential plane, intersects the inner surface of the piston upper part rather than passing through the cooling channel, thereby preventing weld spatter formation inside the cooling channel while maintaining proper weld connection
2Strength
If the laser beam is oriented to weld the joining surfaces, then the piston lower part and upper part are connected, but the laser beam may pass through the cooling channel causing spatter
Solution Approach 1:
The design applies local quality by creating a specific geometric feature (inclined tangential plane) at the joining surface of the piston upper part. This local geometric modification ensures that the laser beam interacts with the inner surface at a specific location, directing the welding energy into the piston material rather than through the cooling channel, thus achieving proper weld strength while preventing spatter
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
Prevents weld spatter from forming inside the cooling channel, ensuring reliable assembly and operation of the piston by ensuring the weld seam does not intersect the cooling channel, thus reducing the risk of damage to the piston and engine.
Implementation Method 1
align a laser beam used for welding in such a way that it runs in the tangential plane
Implementation Method 2
The joining surfaces can be at least partially melted for this purpose
Data Source
AI summary
Piston blank for a piston, comprising a piston lower part, which comprises a first joining surface running around a central axis of the piston blank, and a piston upper part, which comprises a second joining surface running around the central axis and an inner surface running around the central axis and adjoining the second joining surface as viewed along the central axis, wherein the piston upper part can be placed with its second joining surface on the first joining surface, and wherein a tangential plane which is assigned to the second joining surface is inclined relative to the central axis such that the tangential plane intersects the inner surface.