Sliding Component Shallow Grooves Leakage Lubrication
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Solution Overview
Problem
Existing sliding components for mechanical seals and bearings face challenges in reducing leakage and improving lubrication characteristics, especially at startup and stop, where dynamic pressure is insufficient, leading to noise and excessive contact between sealing faces.
Innovation Solution
The implementation of extremely shallow parallel grooves with submicron-level depth and specific roughness on the sealing face, oriented in various directions relative to the sliding direction, to control fluid flow and generate dynamic pressure, thereby reducing leakage and enhancing lubrication characteristics without increasing friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If dynamic pressure-generating grooves are processed to a depth of several μm or more by machining, blasting, or laser, then low friction is achieved in the medium-speed region and high-speed region, but sufficient load capacity cannot be achieved in the low-speed region
Solution Approach 1:
The patent changes the depth parameter of the grooves from conventional several μm to extremely shallow depth of 1 μm or less, and specifically sets the depth within the range of 0.1 μm to 1 μm. This parameter change enables the grooves to generate sufficient dynamic pressure even at low speeds while maintaining low friction characteristics across all speed regions.
Solution Approach 2:
The patent designs the groove depth to be extremely shallow (0.1-1 μm) so that the grooves can dynamically adapt to different operating conditions. At low speeds, the shallow grooves generate adequate dynamic pressure without excessive fluid flow; at medium and high speeds, they maintain low friction while providing sufficient load capacity through optimized dynamic pressure generation.
2Loss of energy
If multiple dynamic pressure-generating grooves are provided to generate dynamic pressure between the sealing faces, then low friction is achieved in the medium-speed region and high-speed region, but sufficient dynamic pressure is not generated at startup and stop
Solution Approach 1:
The patent changes the groove depth parameter to extremely shallow (0.1-1 μm), which enables effective dynamic pressure generation even at startup and stop conditions. The shallow depth ensures that fluid is effectively trapped and pressurized in the grooves, providing sufficient lubrication when the sealing faces are stationary or moving slowly, while maintaining low friction during normal operation.
3Loss of substance
If the clearance h and pressure slope are decreased to reduce the leakage rate, then leakage is reduced, but friction increases and lubrication characteristics deteriorate
Solution Approach 1:
The patent applies local quality by creating extremely shallow grooves (0.1-1 μm depth) at specific locations on the sealing face. These localized groove structures generate dynamic pressure and control fluid flow in specific regions, enabling leakage reduction without compromising overall lubrication characteristics. The grooves are strategically positioned to optimize both sealing and lubrication functions simultaneously.
4Reliability
If conventional dynamic pressure-generating grooves are used, then effective sealing is achieved in the normal rotational speed region, but noise and excessive contact between sealing faces occur at startup and stop
Solution Approach 1:
The patent changes the groove depth parameter to extremely shallow (0.1-1 μm), which prevents excessive contact and noise at startup and stop while maintaining effective sealing during normal rotation. The shallow depth ensures that fluid is trapped effectively in the grooves even at low speeds, providing continuous lubrication and preventing direct contact between sealing faces during transient operations.
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 solution effectively reduces leakage and improves lubrication at startup and stop phases by forming a thin fluid film and adjusting fluid flow direction, maintaining good lubrication performance without increasing leakage, even at low pressures and during rotation in both directions.
Implementation Method 1
generation of dynamic pressure between the sealing faces by means of rotation
Implementation Method 2
creating a so-called fluid lubrication state, which represents a state of surfaces sliding against each other with a liquid film in between
Implementation Method 3
the sealed fluid entering the extremely shallow parallel grooves forms an extremely thin fluid film and the action of its surface tension increases the pressure region where the fluid can be sealed
Data Source
Figure 1(a)~1(d)
Figure 2(a)~2(b)
Figure 3(a)~3(d)
AI summary
{Technical Problem} Provide a sliding component that reduces the leakage rate of sealed fluid and significantly improves the lubrication characteristics at startup or stop, while being actuated by means of fluid lubrication in the rotation phase, thereby achieving the effects of sealing and lubrication at the same time. {Solution to Problem} The sliding component is characterized in that: on one sealing face of a pair of sliding parts that slide relative to each other, multiple positive pressure-generating mechanisms that comprise extremely shallow parallel grooves running roughly in parallel with the sealing face and having submicron-level height differences are provided independently in the circumferential direction; extremely shallow thin grooves are formed on the sealing face on the low-pressure fluid side of the extremely shallow parallel grooves; the extremely shallow parallel grooves communicate with the high-pressure fluid side; and the extremely shallow thin grooves communicate with the extremely shallow parallel grooves, but are isolated from the low-pressure fluid side by a seal area.