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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 8, Issue 2 - Oct 1992
Volume 8, Issue 1 - Apr 1992
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표면처리와 방청유의 선정
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 8, issue 2, 1992, Pages 1~6
Experimental Study on the Friction Characteristics of Friction Modifiers
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 8, issue 2, 1992, Pages 7~13
Wear experiments were conducted using the SRV machine on the lubricated conditions of the several temperature and load. Oil samples were prepared by adding several friction modifiers into both paraffinic base oil and engine oil. Friction and wear characteristics of the oils were determined and are discussed in connection with the friction modifiers contained, the testing temperature and the load applied. From the study, it was found the MoDTC and the MoDTP, added into the engine oil, caused drastic increase in wear and had a tendendy to lose the friction-reducing property on some specific conditions of temperature and/or load, though they had the good property on other conditions. Ashless friction modifiers and dispersed $MoS_2$ investigated showed the good friction-reducing property, but the loads, where they became active, were different.
A Study on Scuffing and the Formation of the Protective Layers Based on Dual Film Formation
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 8, issue 2, 1992, Pages 14~19
rate of growth of "protective" films of oxides and compounds derived from the lubricant. The protection afforded by the films is strongly dependent on lubricant and steel composition, initial composite surface roughness and the load/speed sequence or history in the early stages of sliding. The protective films, formed by chemical and mechanical action between lubricant and mating surfaces, delayed the surface roughening and offered higher load capacity. Given the great number of variables involved it is not possible to follow more than a few of the chemical changes on surfaces at the end of experiments. Ellipsometry was therefore used to monitor the formation and loss of dual protective films in real time, and also to find the effect of protective films on scuffing and break-in depending on lubricant conditions.
A Study on the Friction and Wear Characteristics of $Al_2O_3-TiC$
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 8, issue 2, 1992, Pages 20~25
Friction and wear behavior of hot isostatic pressed $Al_2O_3-TiC$ was experimentally examined. Pin-on-disk type friction and wear apparatus was designed and manufactured for the experiment. The experiments were conducted under unlubricated sliding motion in both low and high humidity for three kinds of sliding speed. $Al_2O_3-TiC$ and bearing steel were used as counterface materials. Friction coefficient, wear rate, and surface roughness were measured. Wear surface and wear debris were observed through optical microscope and SEM and analyzed by EDAX. The results showed that the counterface materials, the sliding speed, and the moisture at the sliding surface have significant influence on the friction coefficient and wear rate of $Al_2O_3-TiC$.
A Flying State Analysis of HDD Head Slider by Using An Optimization Technique
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 8, issue 2, 1992, Pages 26~34
This paper suggests a method to predict the flying state of the head slider in a hard disk drive (HDD) by using an optimization technique. The modified Reynolds equation for the hydrodynamic lubrication theory under the slip flow condition is used to describe the air-bearing system and a Finite Volume Method (FVM) is applied to solve the equation. Especially, Augmented Lagrange Multiplier (ALM) method is employed to find the minimum flying height, the pitch angle and the roll angle of the slider, which is shown to be faster and more general than the conventional update schemes. By using the proposed method, the variations of the flying state are analyzed as a function of the slider position in the direction of the disk radius for various disk velocities and skew angles.
Propagation Analysis of Surface Crack Due to Hertzian Contact
Kim, Seock-Sam ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 8, issue 2, 1992, Pages 35~43
Analysis of Hydrodynamic Lateral Forces Acting on Grooved Pistons in Hydraulic Piston Pumps
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 8, issue 2, 1992, Pages 44~49
Hydrodynamic lateral forces acting on circumferentially grooved and tapered pistons in hydraulic piston pumps are analyzed for the case where the axis of piston and cylinder are tilted with each other. The effects of grooves and tilting on lateral force and leakage flowrate are discussed from the analytical solution of one-dimensional Reynolds equation. The analytical solution is in accordance with the numerical solution of two-dimensional Reynolds equation as the number of grooves increases.
A Study on the Minimum Oil Film Thickness of Crankshaft Main Bearings in Engine
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 8, issue 2, 1992, Pages 50~63
The minimum oil film thicknesses (MOFT) in the crankshaft main bearings of a 1.5 liter, L-4, gasoline engine are measured and calculated to study the dynamically loaded engine bearing. The MOFT are measured simultaneously at each of the five main bearings using the total capacitance method(TCM). To improve the reliability of the TCM, a reasonable determination method of bearing clearance is introduced and the effects of bearipg cavitation and aeration on the test results are analyzed. Also the crankshaft is grounded by means of a slip ring instead of the friction contact method to improve the test precision. The calculation is based on the model of statically determinate beam, short bearing approximation and Mobility method. From the comparison between the measured and calculated MOFT curves, it is found that a qualitative similarity exists between them, but in all cases, measured MOFT are smaller than that of calculated. The crankshaft vibration and the imbalance of the load distribution between the engine bearings have important influence upon the MOFT curve. So it is found that the calculation result from the model of the statically determinate beam has a limitation in predicting bearing performance.
A Study on the Characteristics of Ceramic Ball Bearing
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 8, issue 2, 1992, Pages 64~72
The recent trends of rotating machinery demand high speed and high temperature operation, and the bearing with new material is required to be developed. Ceramic, especially silicon nitride, have been receiving attention as alternative material to conventional bearing steel. Ceramic ball bearing offers major performance advantages over steel bearing, for instance, high speed, maginal lubrication, high temperature, improved corrosion resistance and nonmagnetic capabilities etc.. In this paper, the mechanical characteristics of ceramic ball bearing (hybrid ceramic bearing and all ceramic bearing) were investigated, and the characteristics of ceramic bearing were compared with that of steel bearing. Deep groove ball bearing 6208 was taken the object of analysis. The main results of analysis were followings: the radial stiffness of hybrid and all ceramic bearing were 112% and 130% that of steel bearing, and the axial stiffness of all ceramic bearing was 110% that of steel bearing. According as rotating speed was up, the ball load, the contact angle, the contact stress and the spin-to-roll ratio between ball and raceway of ceramic bearing were far smaller than these of steel bearing. And there was not a significant difference between the minimum film thickness of ceramic bearing and steel bearing. It is expected that this research is contributed to enhanced fundamental technology for the practical applications of ceramic ball bearing.
A Study on the Pressure Characteristics in Low-Friction Piston Pad
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 8, issue 2, 1992, Pages 73~79
The pressure distribution between the piston pad and the cylinder wall is analyzed to reduce the friction and to get the dynamic stability in the low friction piston. The calculated results indicate that the rectangular pad may reduce the friction in comparison to the square one. And the low friction piston can be stabilized when the pressure difference between the top and bottom of the piston skirt is very small.