Load-Zone Recess Plain Bearing for Water-Lubricated Wear Reduction
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Solution Overview
Problem
Existing plain bearings using low-viscosity fluids like water experience increased wear during run-up and lack efficient lubrication, especially in marine applications, where conventional hydrostatic bearings require high-pressure pumps and are costly, and hydrodynamic bearings are not effective.
Innovation Solution
Incorporating small-surface longitudinal recesses in the load zone of the bearing bore, which can be supplied with a pressurized fluid to reduce wear, combining the benefits of hydrostatic and hydrodynamic bearings without the need for high-pressure pumps, and using suitable plastics to minimize mechanical contact wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hydrostatic plain bearings are used to reduce wear, then wear is reduced, but high-pressure pumps are required which increase device complexity and cost
Solution Approach 1:
The patent applies local quality by providing hydrostatic pressure compensation only in the load zone through localized recesses (32) in the bearing bore, rather than requiring system-wide high-pressure pumping. The recesses are positioned specifically in the load zone (30) to provide pressure compensation where needed, while other areas rely on hydrodynamic effects.
Solution Approach 2:
The bearing surface is segmented into different functional zones: load zones with hydrostatic recesses for pressure compensation and non-load zones relying on hydrodynamic lubrication. This segmentation allows the bearing to use different lubrication mechanisms in different areas, reducing the need for high-pressure pumps while maintaining wear protection where most needed.
2Adaptability or versatility
If hydrodynamic plain bearings are used for low-viscosity fluids, then the bearing can operate with water, but wear increases during run-up and the bearing is not effective
Solution Approach 1:
The hydrostatic recesses are pre-filled with lubricant and maintain a reservoir of lubricating fluid in the load zone. During run-up before hydrodynamic pressure builds, this preliminary lubricant supply in the recesses provides immediate wear protection, preventing the increased wear that occurs in conventional hydrodynamic bearings during startup.
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 achieves a 90% reduction in wear and supports loads up to 0.6 MPa, comparable to oil lubrication, with a simpler design that is cost-effective and suitable for marine applications, using a low-viscosity fluid like water.
Implementation Method 1
for wear reduction of the plain bearing the at least one longitudinal recess can be acted upon by an external fluid supply with a fluid under a pressure
Implementation Method 2
hydrodynamic plain bearings operating with water or with other fluids find widespread use for low-maintenance and, due to a developing fluid film, practically friction-free supporting of machine parts
Data Source
AI summary
A plain bearing includes a base body having a substantially cylindrical bore bounded by a bore surface, and the bore surface has a longitudinal recess in a load-zone region that is open radially inward and has curved ends connected by axially extending sides. A cylindrical shaft extends through the bore and over the load zone and has an outer diameter less than an inner diameter of the bore. A fluid channel has an opening in the recess and provides fluid to the recess at a pressure that is maintained at a level to offset no more than about 40 percent of a force produced by the shaft in the direction of the load zone.