Piston Ring Asymmetrical Machining for Thin Profiles
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Solution Overview
Problem
Current grinding disk technology is unable to achieve the necessary axial dimensioning for piston rings with heights less than 2 mm, specifically in internal combustion engines, where a sharp scraping edge is required while maintaining economical machining.
Innovation Solution
The method involves applying a wear-resistant layer to the tapered rail of the piston ring and performing partial material removal only on the rail flank that forms the scraping edge, allowing for asymmetrical machining and increased cycle time efficiency, enabling the production of sharp scraping edges in piston rings with heights as low as 1.5 mm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If symmetrical machining of both rail flanks is performed, then the running surface shape is maintained, but the cycle time increases and productivity decreases
Solution Approach 1:
The patent applies asymmetrical machining by treating only one rail flank (the scraping edge) differently from the other. The active scraping rail flank is machined to a sharp edge with specific geometry, while the inactive rail flank is left unmachined or minimally machined. This asymmetrical approach maintains the necessary running surface shape for the scraping function while reducing total machining time and increasing productivity.
2Manufacturing precision
If the grinding disk machines the entire rail flank depth, then complete material removal is achieved, but the tool wear increases and machining complexity increases
Solution Approach 1:
The patent applies local quality by concentrating the machining action only where needed - specifically on the active scraping rail flank to create a sharp scraping edge. The grinding process is localized to remove material only from the portion of the rail flank that forms the scraping edge, rather than machining the entire rail flank depth. This reduces tool wear and simplifies the machining process while achieving the required functional geometry.
3Length of moving object
If piston ring height is reduced to 1.5 mm or less, then the engine design requirements are met, but the available grinding disk technology cannot achieve the necessary axial dimensioning
Solution Approach 1:
The patent applies parameter changes by modifying the machining approach specifically for small-diameter, low-height piston rings. Instead of using conventional grinding disk technology that cannot achieve the necessary axial dimensioning for rings with height of 1.5 mm or less, the invention changes the machining parameters and method to profile grind only the active scraping rail flank. This enables precise axial dimensioning and sharp scraping edge formation in miniaturized piston rings that meet modern engine design requirements.
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 allows for the production of piston rings with high shape conformity and low tangential forces, enabling efficient machining of sharp scraping edges in smaller dimensions, particularly in gasoline and diesel engines, while maintaining economical production.
Implementation Method 1
the running surface of, for example, electroplated, profile-ground spiral expander rings
Implementation Method 2
profile-grinding the running rail flanks so that a defined cylindrical remaining surface is produced
Data Source
AI summary
Method for producing a piston ring having an axial height <2 mm, said piston ring having a radially outer running surface provided with at least one rail, a radially inner circumferential surface, and upper and lower flank surfaces extending therebetween, wherein said rail is provided with a contour that is tapered radially outwardly, thereafter the running surface, together with the flanks of the tapered rail, is provided with at least one wear-resistant layer, and then only the flank of the rail that is to form a scraping edge is subjected to at least partial material removal to form the scraping edge.