Random Dimple Distribution for Sliding Parts Friction
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Solution Overview
Problem
Existing sliding parts with dimples on sealing faces do not adequately address the influence of dimple opening diameters on friction reduction and sliding characteristics, particularly at varying temperatures and low speeds.
Innovation Solution
Randomly distributing dimples of different diameters on the sealing faces, with diameters ranging from 30 to 100 μm and depths between 50 to 1,000 nm, to improve sliding characteristics and reduce friction coefficients, while maintaining effective sealing and lubricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If dimples are provided on a sealing face to reduce friction, then sliding characteristic is improved, but sealing property deteriorates due to fluid leakage
Solution Approach 1:
The sealing face is divided into different regions with different properties: a dimple formation region containing multiple dimples for reducing friction, and a flat seal face region for maintaining sealing. This local differentiation allows each region to perform its specific function optimally without interfering with the other.
Solution Approach 2:
The sealing face is segmented into distinct functional zones: the dimple formation region (with multiple separated dimples) and the flat seal face region. This segmentation ensures that the friction-reducing dimples are confined to a specific area while the sealing function is maintained in another area.
2Ease of manufacture
If dimples with uniform depth are provided on sealing face, then manufacturing is simplified, but sliding property deteriorates at varying temperatures due to unstable load capacity
Solution Approach 1:
Dimples with different depths are strategically arranged in different regions of the dimple formation area. Dimples with greater depth provide higher load capacity at low temperatures, while dimples with smaller depth maintain stable load capacity at high temperatures, creating a composite effect that stabilizes sliding properties across temperature variations.
Solution Approach 2:
The dimple structure functions as a composite system combining multiple depth variations (50-200 nm and 200-1000 nm ranges) within the same sealing face, analogous to composite materials that combine different properties to achieve superior overall performance.
3Ease of operation
If large number of dimples are arranged on sealing face to improve lubrication, then friction coefficient is reduced, but sealing performance deteriorates due to increased leakage paths
Solution Approach 1:
The sealing face is divided into a dimple formation region (for lubrication) and a flat seal face region (for sealing). By confining dimples to a localized region rather than distributing them across the entire sealing face, the invention maintains sealing integrity while providing sufficient lubrication in the designated area.
Solution Approach 2:
The sealing face is segmented into functional zones where dimples are concentrated in the dimple formation region, separated from the flat seal face region. This segmentation creates distinct zones for lubrication and sealing functions, preventing the trade-off between the two.
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 friction coefficients across a wide range of bearing characteristic numbers, enhances sliding performance at low speeds, and ensures simultaneous sealing and lubricity, with no leakage observed during testing.
Implementation Method 1
a load capacity due to a fluid bearing pressure generated in a fluid lying between the sealing face and the opposing sealing face at the time of sliding
Implementation Method 2
there has been an even greater demand for lower friction in order to reduce mechanical loss while preventing leakage of a sealed fluid... by applying various texturing. For example, there is a known method of arranging dimples on a sealing face
Data Source
AI summary
By randomly arranging dimples provided on a sealing face, a sliding characteristic is improved in a wide range of a bearing characteristic number on the sealing face. A pair of sliding parts in which a plurality of dimples is arranged on at least one of sealing faces that relatively slide on each other is characterized in that each of the plurality of dimples is provided independently from the other dimples, and arranged in such a manner that the plurality of dimples having different opening diameters is randomly distributed.