Mechanical Seal Sliding Member With Femtosecond Laser Grating
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Solution Overview
Problem
The lubricating characteristics of mechanical seal sliding members are hindered by insufficient fluid film thickness and partial fractures leading to increased coefficient of friction and temperature at the sliding surface, resulting in suboptimal performance and potential leakage.
Innovation Solution
A mechanical seal sliding member with a periodic grating structure formed by irradiating a linearly polarized femtosecond laser on the sliding surface, creating fine ridges that enhance lubrication by maintaining a stable fluid film without excessive leakage, achieved through precise control of ridge pitch, depth, and orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a silicon carbide sliding member contacts another silicon carbide sliding member, then the PV limit increases and performance improves, but abnormal noise and linking occur at startup period
Solution Approach 1:
The patent applies preliminary action by forming a liquid reservoir in advance within the sliding member structure. This reservoir stores lubricating liquid that is automatically discharged when frictional heat generates during operation, particularly at startup period, to form a lubricating film before solid contact occurs, thereby preventing abnormal noise and linking while maintaining high PV limit performance
2Reliability
If a carbon material sliding member contacts a silicon carbide sliding member, then sealing performance improves, but carbon blisters and microcracks form on the sliding surface
Solution Approach 1:
The patent utilizes porous materials by incorporating a liquid reservoir with controlled porosity (5-50% volume ratio) into the sliding member. This porous structure stores and controls the release of lubricating liquid, which forms a protective film between the carbon and silicon carbide surfaces, preventing direct contact that would cause carbon blisters and microcracks while maintaining effective sealing performance
3Power
If cemented carbide and carbon material sliding members are used in freezer applications, then high PV value is achieved, but thermal shock produces heat cracks and carbon bulges
Solution Approach 1:
The patent applies parameter changes by modifying the physical state and distribution of lubricating liquid through temperature-dependent parameters. The liquid reservoir maintains optimal lubrication parameters across varying temperatures by automatically adjusting liquid discharge based on frictional heat generation, preventing thermal shock-induced cracks and bulges while sustaining high PV values in freezer applications
4Reliability
If the fluid lubricating film thickness is increased, then lubricating characteristics improve, but fluid leakage increases
Solution Approach 1:
The patent extracts the lubricating liquid from the general fluid system and stores it separately in a dedicated liquid reservoir (5-50% volume ratio of the sliding member). This extracted liquid is then controlled to discharge only where and when needed through frictional heat activation, forming a localized lubricating film that improves lubricating characteristics without causing excessive fluid leakage from the seal system
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 effectively reduces the coefficient of friction and stabilizes the sliding surface temperature, improving lubricating characteristics and sealing efficiency while minimizing fluid leakage, as demonstrated by the formation of fine grating sections using femtosecond laser technology.
Implementation Method 1
a periodic grating structure formed by irradiating a linearly polarized femtosecond laser on the sliding surface
Implementation Method 2
irradiating a linearly polarized femtosecond laser with irradiating energy adjacent to a process threshold level to a material surface
Implementation Method 3
improve lubricating characteristics such as lowering and stabilizing the coefficient of friction
Data Source
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AI summary
The present invention provides a mechanical seal sliding member with high lubricating characteristics, in which the coefficient of friction and the temperature of sliding surfaces are lowered and stabilized without excessive leakage. In the mechanical seal sliding member of the present invention, on the sliding surface 2, a plurality of grating sections 5 are formed separately in each of which a plurality of linear shape ridge portions parallel to each other are formed in a predetermined region with a predetermined pitch. The linear shape ridge portions of the plurality of grating sections are formed as inclined at a predetermined angle to a sliding direction of the sliding surfaces 2. Such periodic structure can improve the lubricating characteristics for lubrication. By irradiating a linearly polarized femtosecond laser with irradiating energy adjacent to a process threshold level to a material surface, a fine periodic structure with a cycle interval comparable with a laser wavelength and with a ridge depth half or less than the laser wavelength can be formed by a self-structuring manner.