Piston Ring Wire Geometry for Uniform Narrow Contact Width
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Solution Overview
Problem
Conventional methods struggle to form a piston ring with a small and uniform contact width due to limitations in shaping the corner portion of the wire, which affects the surface pressure and oil scrape-off performance.
Innovation Solution
A wire design with a tapered surface and a protruding surface divided by a virtual surface, allowing the corner portion to be formed sharp during the coiling process, enabling a small and uniform contact width independent of the die shape, and further enhanced by a surface treatment for reduced friction and improved abrasion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the lapping time is lengthened to obtain uniform contact width, then the contact width becomes uniform, but the contact width excessively increases causing drop in surface pressure
Solution Approach 1:
The wire is pre-formed with a corner portion having a predetermined shape before the lapping process. This preliminary shaping allows the lapping process to be more efficient and controlled, achieving uniform contact width without excessive lapping time that would otherwise increase contact width too much and reduce surface pressure.
Solution Approach 2:
The invention changes the geometric parameters of the wire corner portion (forming it with specific dimensions and shape before lapping) to optimize the lapping process outcomes. By controlling the initial corner portion dimensions, the final contact width and surface pressure can be precisely controlled without the trade-off present in conventional methods.
2Stress or pressure
If the contact width is reduced to maintain surface pressure, then surface pressure is maintained, but the contact width becomes non-uniform
Solution Approach 1:
The corner portion of the wire is pre-formed with precise dimensions and shape before the lapping process. This preliminary action ensures that the starting geometry is optimized, allowing the lapping process to produce both uniform contact width and adequate surface pressure simultaneously, rather than requiring a trade-off between these two parameters.
Solution Approach 2:
By changing and controlling the geometric parameters of the wire corner portion in advance (width, height, shape), the invention enables the lapping process to achieve both uniform contact width and sufficient surface pressure without compromising either parameter.
3Manufacturing precision
If the corner portion is made sharper to reduce contact width, then contact width decreases, but it becomes difficult to form due to die shape restrictions
Solution Approach 1:
The corner portion is pre-formed during the wire manufacturing process with a shape that is optimized for the subsequent lapping operation. This preliminary formation allows the creation of a sharp corner portion that would be difficult to achieve directly, by preparing the geometry in advance through controlled forming processes that are more capable than direct die drawing.
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
The solution achieves a small and uniform contact width, improving surface pressure and oil scrape-off performance while reducing friction and enhancing durability of the piston ring.
Implementation Method 1
an oil film can be formed due to a wedge effect between the tapered surface and the cylinder inner wall during a rising stroke of the piston
Implementation Method 2
The contact surface is formed by lapping the outer circumferential surface of the ring in the polishing step
Implementation Method 3
a coiling step of plastically processing a strip-shaped wire into an annular shape
Data Source
AI summary
In a surface of a wire, a first side surface forming an outer circumferential surface in a piston ring includes a tapered surface and a protruding surface, the protruding surface is divided into a first part and a second part by a first virtual surface extending from the tapered surface, and the first part includes a top and is formed in a protruding shape.