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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Tribologists and Lubrication Engineers
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Journal DOI :
The Korean Society of Tribologists and Lubrication Engineers
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Volume & Issues
Volume 11, Issue 5 - Dec 1995
Volume 11, Issue 4 - Dec 1995
Volume 11, Issue 3 - Sep 1995
Volume 11, Issue 2 - Jun 1995
Volume 11, Issue 1 - Mar 1995
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Viscosity Index Enhancement Through Dumb-Bell Blending of Lubricants
Shim, Joo-Sup ; Cho, Won-Oh ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 11, issue 2, 1995, Pages 1~7
Viscosity index is an arbitray number used to characterize the variation of lubricant viscosity with respect to temperature. It is well recognized in the oil industry that as refining severity increases, lubricant VI increases. Consequently, VI is often perceived as a measure of lubricant quality. Futhermore, a 95 VI minimum specification is commonly imposed in marketing base stocks. These factors provide the incentitive for this study to carefully analyze VI definition and two component viscosity blending techniques to investigate how they affect VI change, and finally to examine possible avenues to produce 95+VI base stocks by blending sub-95 VI base stocks.
A Study on The Filtration Characteristics of Magnetic Fibrous Polymeric Filter with Packing Density Profile as a New Oil Filter
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 11, issue 2, 1995, Pages 8~14
The filtration of the magnetic fibrous polymeric filter with packing density profile made of a self-bonded, nonwoven structure comprising a thermoplastic polymer and a magnetic substance was investigated using an oil filter tester, a particle quantifier and an image analyzer system. The magnetic fibrous polymeric filter showed excellent filtration efficiency compared with conventional paper filter. From the experimental results, It is deduced that the filtration mechanism of conventional paper filter is only the function of physical porosity by surface filteration. On the other hand, the newly magnetic fibrous polymeric filter is designed with a new concept in filtration mechanism. That is, it has a dual function of depth and magnetic filters by physical porosity and magnetic attraction. The newly magnetic fibrous polymeric filter has been shown to be a highly effective oil filter for lubrication systems.
A Study on the Flying Characteristics of Zero-Load Sliders
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 11, issue 2, 1995, Pages 15~23
A zero-load slider is composed of two outside rails which produce a lift force pushing up the slider from the disk surface and a wide reverse step region which produces a suction force attracting the slider to the disk surface. In this paper, the flying characteristics of zero-load sliders are obtained by using an optimization technique. In the pressure calculation module, the FIFD scheme is used to solve the modified Reynolds equation. The BFGS method and a line search algorithm is employed to predict the static flying attitude. To investigate the effect of the geometric- parameters of zero-load sliders on the flying characteristics, recess depth, front step width, rail width, and taper height are varied and the corresponding flying attitudes are obtained. Simulation results demonstrate that recess depth and rail width have significant influences on the flying characteristics.
Analysis of Contact Stress in Slewing Ring Bearings
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 11, issue 2, 1995, Pages 24~33
This paper presents the contact stress distributions between the multi-contact bodies and the total reaction forces for various types of contact geometry for multi-load slewing ring bearings. The FEM results indicate that the slope of the roller type of slewing ring bearing has slightly steeper than that of the ball type. This is because the roller type wire race bearings is stiffer than the ball type bearing. The total reaction force of ball type slewing bearing shows much higher than that of wire race slewing bearings.
Characterization of the Boundary Films Formed in Lubricated Sliding at High Temperatures
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 11, issue 2, 1995, Pages 34~43
The boundary films formed in sliding on steel surfaces were characterized using various lubricants. The mechanism of boundary film formation and loss was investigated over a range of temperature. The thickness of the boundary films was monitored in-situ by an ellipsometer, and the composition of the films was analyzed by XPS. The performance of the lubricants is closely associated with boundary film forming ability. In order to achieve high load carrying capacity, a boundary film must be formed on the surface. Sliding is necessary to form the films and some time is also required. As temperature increases, chemical reactivity increases the film formation rate, while the film removal rate increases due to thg decrease of durability of the boundary film material. There is a balance between these two competing mechanisms and this balance is reflected in the boundary film thickness.
Sliding Frictional Characteristics with the Change of Dynamic Parameters in the Friction Measurement
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 11, issue 2, 1995, Pages 44~55
Frictional characteristics with the change of dynamic parameters, such as stiffness, inertia and damping, in the friction measurement at dry sliding surfaces were experimentally and theoretically investigated throughout the study. Dynamic frictional force and the variation in the normal load were mainly measured at the various conditions of system dynamic parameters with which stiffness in the normal direction, loading mechanisms and test materials were varied. For the normal load, mechanisms using both a dead weight and a pneumatic cylinder were applied, which resulted in change of the inertia and damping of the test rig. Test materials were steel, rosin and PTFE, which have different types of intrinsic frictional characteristics. Test results showed that frictional characteristics under different dynamic parameters could be different even though the operating variables were the same and also they could result in the variation in the normal load, which could consequently affect the wear mechanism.
A Study on the Stability Improvement of Rotor System Supported by Hydrodynamic Bearing
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 11, issue 2, 1995, Pages 56~62
The anisotropic pressure distribution of the hydrodynamic bearing may generate the unstable vibration phenomenon over a certain speed. These vibrations, known as whirl, whip or rotor instability, cannot be sustained over a wide range of rotational spees. Besides these vibrations not only perturb the normal operation of a rotating machine, but may also cause serious damage to the machinery system. And, it is really impossible to change one parameter without changing others, or difficult to fabricate the modified non-circular type bearing, with all the other cures used just now, In this study, hybrid bearing with magnetic exciter is designed for stability improvement of hydrodynamic bearing rotor system without changing mechanical parameters. For stability study, eigenvalue study of the bearing-rotor system is executed by finite element method and results of analyses and experiments show the possibilities of the stability improvement of the hydrodynamic bearing system by using the electricmagnetic force.
Design and Analysis of Gerotor for Hydraulic Motors
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 11, issue 2, 1995, Pages 63~70
The analytical design method of gerotor profile, based on an envelope of a family of curves, is proposed. Analysis to calculate the flow rate and the torque capacity of a gerotor set are presented. The influence of the circular tooth radius and the amount of eccentricity on the configuration of a gerotor has been explored in this paper. The variation of the inlet volume and the fluctuation of the generated torque are also analyzed.