Sliding Seal Groove Layout for Stable Fluid Film Lubrication
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Solution Overview
Problem
Existing sliding components require numerous evenly distributed dynamic pressure generating grooves, which lead to unstable fluid film thickness and lubrication, compromising sealability and lubricity.
Innovation Solution
Grouping dynamic pressure generating grooves into unevenly distributed groups with longer central grooves and shorter peripheral grooves, forming a spiral pattern, to stabilize fluid film thickness and enhance lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large number of dynamic pressure generating grooves are evenly distributed in the circumferential direction, then the sealed fluid can be sufficiently drawn in, but the land portions become too small to hold a stable fluid film
Solution Approach 1:
The sliding surface is segmented into multiple dynamic pressure generating groove groups, where each group contains multiple grooves arranged in specific patterns. This segmentation allows sufficient fluid intake through multiple grooves while creating larger land portions between groups that can stabilize the fluid film.
Solution Approach 2:
The dynamic pressure generating grooves within each group are arranged asymmetrically rather than being evenly distributed. This asymmetric arrangement creates varying land portion sizes that can simultaneously draw in fluid effectively and provide stable regions for fluid film holding.
2Speed
If dynamic pressure generating grooves are evenly distributed, then fluid can be drawn uniformly, but the groove unprocessed section cannot be secured to stabilize fluid film thickness
Solution Approach 1:
Different regions of the sliding surface are given different qualities: some regions contain dynamic pressure generating grooves for fluid intake, while other regions (groove unprocessed sections) are left without grooves to provide stability. This local differentiation allows both efficient fluid drawing and stable fluid film formation.
3Reliability
If many grooves are formed to prevent leakage, then sealing is improved, but friction increases due to insufficient lubrication
Solution Approach 1:
The dynamic pressure generating grooves act as intermediaries that draw in sealed fluid to create a fluid film between the sliding surfaces. This fluid film serves as a mediator that reduces direct contact friction while the grooves themselves prevent leakage, thus resolving the contradiction between sealing and lubrication.
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
Stabilizes fluid film thickness and improves lubrication by securing a large groove unprocessed section, effectively generating dynamic pressure and preventing fluid leakage.
Implementation Method 1
a fluid (here, a sealed fluid) is drawn into the dynamic pressure generating groove from one end corresponding to the start point of the dynamic pressure generating groove due to the relative rotation between two sliding components so that a dynamic pressure is generated at the front end portion
Implementation Method 2
since a so-called fluid lubrication state is exhibited in which a sliding action is performed while a fluid film is interposed between the sliding surfaces, it is possible to lower the friction between the sliding components
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
There is provided a sliding component capable of securing a groove unprocessed section having a size capable of stably holding a fluid film while sufficiently securing lubricity of a sliding surface. A sliding surface (S) of an annular sliding component (3, 6) disposed at a relatively rotating position of a rotating machine is provided with a plurality of dynamic pressure generating groove groups (20) arranged in a circumferential direction, each including a plurality of dynamic pressure generating grooves (G) having a start point (21) opening to one radial edge of the sliding surface (S) and an end point (22) closing within the sliding surface (S) while extending circumferentially, in the circumferential direction and dynamic pressure generating grooves (G2 to G16) provided between the dynamic pressure generating grooves located at both ends the dynamic pressure generating groove groups are formed to be longer than the dynamic pressure generating grooves (G1 and G17) located at the both ends of the dynamic pressure generating groove group (20) in the circumferential direction.