• Tribology and Lubricants
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• v.26 no.4
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• pp.240-245
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• 2010

This paper describes the influence on engine main bearing behavior of the oil film when the fuel is diluted on a diesel engine equipped with DPF system. Oil film pressure and the thickness is calculated in accordance to the fuel dilution. The calculation is based on the numerical analysis of the engine main bearing. As a result, the engine oil viscosity decreased as the fuel dilution increased. This led the increment of the maximum oil thickness pressure. Verification of the minimum oil film thickness settlement by the engine gas pressure and the fuel dilution was confirmed. Destruction possibility of the engine main bearing was foreseen when the engine speed was 2000 rpm with the fuel dilution 15% and the 5W40 engine oil.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.5
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• pp.88-95
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• 2015

The thickness of adsorbed molecular layers is the most critical factor in studying thin-film lubrication, and it is the most essential parameter that distinguishes thin-film from thick-film lubrication analysis. The thin film between the shaft and bearing surface within a very narrow gap was considered. The general Reynolds equation has been derived for calculating thin-film lubrication parameters affecting the performance of the circular journal bearing. Investigation of the load-carrying capacity and pressure distribution for the journal bearing considering the adsorbed layer thickness has been carried out. A Reynolds equation appropriate for the journal bearing is used in this paper for the analysis, and it is discussed using the finite difference method of the central difference scheme. The parameters, such as eccentricity and attitude angle, are used for discussing the load-carrying capacity of the journal bearing. The results reported in this paper should be applied to analysis of the journal bearing with different lubrication factors. The steady-state analysis of the journal bearing is conducted using the Reynolds model under thin-film lubrication conditions. For a journal bearing, several parameters, such as a pressure, load capacity, and pressure components of the bearing can be obtained, and these results can be stored in a sequential data file for later analysis. Finally, their distribution can be displayed and analyzed easily by using the MATLAB GUI technique. The load-carrying capability of the journal bearing is observed for the specified operating conditions. This work could be helpful for the understanding and research of the mechanism of thin-film lubrication.

• Journal of Korean Society of Steel Construction
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• v.17 no.6 s.79
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• pp.717-726
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• 2005

This study investigates the bearing pressure distribution and design of an H-section steel column baseplate under concentric loading. In general, the size and thickness of the baseplate are determined with the assumption that the bearing pressure of the column baseplate is distributed uniformly. When the column is loaded lightly, however, the baseplate becomes smaller andthinner and the bearing pressure of the baseplate is distributed non-uniformly. In this study, the distribution of the bearing pressure is investigated using the experimental method and the analytical method. Seven specimens of the H-section steel column baseplate were fabricated and tested. The analysis of the specimens was performed using the finite element analysis program, ANSYS. It is not appropriate to use the Limit State Design,which assumes that the bearing pressure of the baseplate is distributed uniformly,because the bearing pressure is distributed non-uniformly and is concentrated under the column sectio.

• Journal of Korean Society of Steel Construction
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• v.16 no.4 s.71
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• pp.463-470
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• 2004

In this study, the bearing pressure distribution and design method of rectangular steel tubular column base plates under concentric loading were investigated. In general, the size and thickness of the baseplate are determined with the assumption that the bearing pressure of the column baseplate is uniformly distributed. When the column is loaded lightly, however, the size of the baseplate becomes smaller, the thickness becomes thinner and the bearing pressure of the baseplate is not distributed evenly. In this study, the distribution of the bearing pressure was investigated using the experimental and analytical methods. Four test specimens of the rectangular steel column baseplate were fabricated and tested. The analysis of the specimens was done using the finite element analysis program ANSYS. The result was that it was appropriate to use the effective width method to design the lightly loaded column baseplate, because the bearing pressure was not distributed evenly and was only concentrated under the column section.

• Transactions of The Korea Fluid Power Systems Society
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• v.7 no.3
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• pp.7-12
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• 2010

In the case of hydraulic piston motor, hydrostatic bearing is designed to be adapted the hydrostatic bearing for the relative lubrication in the structural design. It's available to make it highly efficient and that's why it's widely used. The thing which largely influence the high pressure, the high efficiency, and the life is the hydrostatic bearing between a shoe and a swash plate. In this study, with the most general "hydrostatic bearing shoe" that has one recess as the subject of this research, I designed and made the 4 kind of piston shoe that have different orifice diameter each other, and studied the features of the hydrostatic bearing by observing the change of the leakage flow rate, the torque and the volumetric efficiency through experiments on the changes of the pressure & the speed of the revolution. As a result, the bigger diameter of the orifice, the less torque. And with an increase of the orifice diameter under the high pressure, the leakage flow rate decreased remarkably. Also it was observed the leakage flow rate increased linearly according to the increase of the supply pressure.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1989.11a
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• pp.94-99
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• 1989

This paper analyzes file stiffness, damping coefficient, friction force and flow coefficient of externally pressurized oil journal beating, including the effect of journal rotation according to the Sommerfeld number. This paper assumed that the oil in the whole pocket has constant pressure, and that the oil in the whole bearing region has constant viscosity, temperature and density. Reynolds equation is derived from Nuvier - Stokes equation and continuity equation. And solved bearing pressure by ADI method for whole bearing region and fitted with out flow rate of pocket region. The model for numerical simulation is hydro - static oil journal bearing for high-speed, high-accuracy lathe spindle.

• Tribology and Lubricants
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• v.17 no.6
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• pp.467-475
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• 2001

Feasibility study of gas-lubricated bearing in micro gas turbine was performed. Based on Reynolds equation, finite difference method with coupled boundary was developed to analyze bearing characteristics, such as load capacity, mass flow rates and stiffness. By the bearing force and mass flow rates analysis with the variation of supply pressure, bearing clearance and capillary radius, acceptable range of design parameters were suggested in terms of load capacity and stiffness of bearings. Additionally, coupled boundary effect on pressure distribution was investigated and it is stated that coupling could reduce an excitation force due to narrow pressure distribution.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.11a
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• pp.273-281
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• 2001

Feasibility study of gas-lubricated bearing in micro gas turbine was performed. Based on Reynolds equation, finite difference method with coupled boundary was developed to analyze bearing characteristics, such as load-carrying capacity, mass flow rates and stiffness. By the bearing force and mass flow rates analysis with the variation of supply pressure, bearing clearance and capillary radius, acceptable range of design parameters were suggested in terms of load capacity and stiffness of bearings. Additionally, coupled boundary effect on pressure distribution was investigated and it is stated that coupling could reduce all excitation force due to narrow pressure distribution.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.5 no.3
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• pp.92-98
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• 2006

In this study, the behavior characteristics of a hydrostatic thrust bearing used in hydraulic equipment was analyzed using a commercial finite element program, ADINA. The solid domain was modeled with the fluid domain simultaneously to solve the fully coupled problem, because this is a problem where a fully coupled analysis is needed in order to model the fluid-structure interaction(FSI). The results such as bearing deformation, stress, film thickness and lifting bearing force were obtained through FSI analysis, and then they were compared with the results calculated from the classical method, a single step sequential analysis. It was found that the result difference between two analyses was increased according to the injection pressure. Therefore, in case of high pressure loading, it is desirable to conduct the FSI analysis to examine the deformation characteristics of a hydrostatic slipper bearing.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.75-78
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• 2005

In this paper, an experimental study on porous air bearing stiffness for ultra precision positioning system was performed. In general manufacturer provide bearing stiffness under specific air pressure, but the air pressure used in the field is different. Therefore it is necessary to know the stiffness of air bearing under the pressure used in the field. In order to know that, experimental device which can realize actual operating conditions was made. Using this device, static and dynamic stiffness of air bearing can be obtained. As a result, displacement error occurred around 1 $\mu$m at recommended load.