Piston Ring Contact Surface Shaping for Uniform Narrow Width
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Solution Overview
Problem
Conventional methods struggle to form a contact surface with a small and uniform width on piston rings with a tapered outer circumferential surface due to limitations imposed by the shape of the die used in manufacturing, leading to increased friction and potential deterioration in oil scrape-off performance.
Innovation Solution
A manufacturing method for piston rings involves a wire with specific side surfaces and protruding surfaces that are deformed during the coiling process to form a sharp corner portion, which is then polished to create a flat contact surface, allowing for a uniform and small contact width independent of die constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the lapping time is lengthened to obtain uniform contact width, then the contact width increases excessively, but the surface pressure drops and oil scrape-off performance deteriorates
Solution Approach 1:
The wire is pre-formed with a protruding surface that creates a corner portion with a predetermined small contact width before the lapping process. This preliminary shaping allows the lapping step to focus only on surface finishing rather than material removal for dimension control, thereby achieving uniform contact width without excessive lapping time and preserving surface pressure for effective oil scrape-off
2Ease of operation
If the contact width is reduced to improve surface pressure, then oil scrape-off performance improves, but the contact surface area decreases and may affect initial adaptivity
Solution Approach 1:
The protruding surface is designed to create a corner portion with a locally concentrated small contact width at the specific location where initial adaptivity is most critical. This localized contact geometry provides sufficient surface pressure for oil scrape-off while maintaining adequate overall contact area through the tapered surface configuration, thereby balancing both oil scrape-off performance and initial adaptivity
3Manufacturing precision
If the wire is molded with a sharp corner to achieve small contact width, then the die shape constraints limit the minimum achievable corner radius
Solution Approach 1:
The wire is pre-formed with a protruding surface that creates a corner portion with a predetermined small contact width before the lapping process. This preliminary shaping allows the lapping step to focus only on surface finishing rather than material removal for dimension control, thereby achieving uniform contact width without excessive lapping time and preserving surface pressure for effective oil scrape-off
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 method enables the formation of a piston ring with a small and uniform contact width, improving initial adaptivity and reducing friction while maintaining effective oil scrape-off performance.
Implementation Method 1
a coiling step of plastically processing a strip-shaped wire into an annular shape
Implementation Method 2
a lapping process of lapping the outer circumferential surface of the ring
Implementation Method 3
an oil film can be formed due to a wedge effect between the tapered surface and the cylinder inner wall
Data Source
Figure 1
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Figure 3
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.