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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 27, Issue 6 - Dec 2011
Volume 27, Issue 5 - Oct 2011
Volume 27, Issue 4 - Aug 2011
Volume 27, Issue 3 - Jun 2011
Volume 27, Issue 2 - Apr 2011
Volume 27, Issue 1 - Feb 2011
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Bending Mode Vibration Control of a Flexible Shaft Supported by a Hybrid Air-foil Magnetic Bearing
Jeong, Se-Na ; Ahn, Hyeong-Joon ; Kim, Seung-Jong ; Lee, Yong-Bok ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 27, issue 2, 2011, Pages 57~64
DOI : 10.9725/kstle.2011.27.2.057
Hybrid air-foil magnetic bearing integrates two oil free bearing technologies synergetically to adopt the strengths of two bearings with minimizing their weaknesses. This paper presents bending mode vibration control of a flexible shaft supported by the hybrid air-foil magnetic bearing. An experiment set-up of a flexible shaft supported by the hybrid air-foil magnetic bearing is built. In order to verify the effectiveness of the hybrid bearing, unbalance responses of the flexible shaft supported by three different bearings: air-foil, magnetic and hybrid bearings are compared. Effect of load sharing between air-foil and magnetic bearings are investigated through changing the control gain and the rotor center position of magnetic bearing. The experimental results shows that the hybrid bearing can control the bending mode vibration of the flexible shaft effectively and an optimal performance can be achieved with an appropriate load sharing between the air-foil and the magnetic bearings.
Wear Characteristics of AlBC for Piston Head of Power Servo Cylinder
Cho, Yon-Sang ; Park, Heung-Sik ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 27, issue 2, 2011, Pages 65~70
DOI : 10.9725/kstle.2011.27.2.065
The power servo cylinder for driving accurately turbine stop valve of an atomic power plant is necessary to do turn-over owing to a leakage of oil and a structure problem, especially, it of a power plant be in demand a high quality standard depends entirely on import. There are much problem that the AlBC be to used as a material of piston head in cylinder are caused by wear. Therefore, it is necessary to examine friction characteristics of it. In this study, wear test experiments was carried out with AlBC and SCM440, using reciprocating friction tester of pin on disk. This result was shown that the wear mechanism of AlBC on working condition is adhesive wear and the maximum temperature of infra redray thermal image of frictional surface show over 2 mm from contact surface of pin and disk.
Theoretical Analysis of Water Hydrostatic Journal Bearings
Park, Seong-Hwan ; Park, Sang-Shin ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 27, issue 2, 2011, Pages 71~76
DOI : 10.9725/kstle.2011.27.2.071
In this study, the nondimensional load capacity of water hydrodynamic journal bearings is calculated. A generalized coordinate formulation is applied to handle the complexity of bearing geometry. A window-based analysis program is developed to analysis the cylindrical hydrostatic bearings. Load capacities are calculated according to some design parameters such as clearance, diameter of orifice, size of recesses and temperature. The results are presented and discussed.
Thermohydrodynamic Lubrication Analysis of Journal Bearing on Steam Turbine Shipping Engine Involving the Mixture of Water within Turbine Oil
Chun, Sang-Myung ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 27, issue 2, 2011, Pages 77~87
DOI : 10.9725/kstle.2011.27.2.077
In this study, using the governing equation for thermohydrodyamic lubrication involving the homogeneous mixture of incompressible fluid derived by based on the principle of continuum mechanics, it is discussed the effects of water within turbine oil on the performance of high speed journal bearing of a steam turbine shipping engine. The governing equation is the general equation being able to be applied on the mixture of Newtonian fluid and non-Newtonian fluid. Here, the fluid viscosity index, n of power-law non-Newtonian fluid is supposed to be 1 for the application of the journal bearing in a steam turbine shipping engine lubricated with the mixture of two Newtonian fluid, for example, water within turbine oil. The results related with the bearing performance are showed.
Wear and Friction Behavior on the Surface of Swash Plate of Compressor for Air Condition System of Automobile
Kwon, Yun-Ki ; Lee, Geon-Ho ; Lee, Ki-Chun ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 27, issue 2, 2011, Pages 88~94
DOI : 10.9725/kstle.2011.27.2.088
The tribological characteristics of the swash plate surface of a compressor which is for automobile were investigated. For surface treatments, PTFE and
are used as a solid lubricant, together with copper alloy. Test condition is set considering actual driving condition. Wear testing is conducted using pin on disk type tester, and the coefficient of friction and the temperature on friction surface are measured. Also, to determine the wear patterns, cross-section of friction surface is analyzed by SEM(scanning electrode microscope). The
, both at dry and lubricated conditions, friction surface and the coefficient of friction maintained rather stable results. But, the PTFE, at oil less condition, sample resulted in rather unstable condition. In case of copper alloy, quite higher friction coefficients(higher than 0.1) were obtained at dry condition. At the temperature of
, seizure has occurred.
Characteristics Evaluation of Light Brake disc and Linning for Railway Vehicle In Terms of Tribology
Kim, Sung-Kwon ; Lee, Hi-Sung ; Kwon, Seok-Jin ; Kwon, Sung-Tae ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 27, issue 2, 2011, Pages 95~100
DOI : 10.9725/kstle.2011.27.2.095
The brake disc materials for railway vehicle have been mainly used cast-iron. The brake disc and pad should be light, resist to a thermal crack and absorb enough friction energy. In order to satisfy this requirement, aluminum alloy brake disc for railway vehicle has been newly developed. The aluminum itself has not been considered the friction material for railway vehicle. However, in the case of aluminum composite with dispersed ceramic particles, friction characteristics, resistance to wear and heat are much improved. In the present study, aluminum composite brake disc of 20% ceramic particle and three kinds of organic pads have been tested in dynamometer. The results show that Al MMC brake disc and pad have good friction coefficient and wear rate, and thermal cracks in brake disc have not been initiated. Also, the Al MMC brake disc can be applied to railway vehicle of 150 km/h.
Frictional Loss Analysis of a Reciprocating Compressor with Thrust Ball Bearing
Kim, Tae-Jong ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 27, issue 2, 2011, Pages 101~108
DOI : 10.9725/kstle.2011.27.2.101
In this paper, a study on the frictional losses and dynamic behaviors of a reciprocating compression mechanism used in small refrigeration compressor is performed. In the problem formulation of the compressor dynamics, the viscous frictional force between piston and cylinder wall is considered in order to determine the coupled dynamic behaviors of piston and crankshaft supported on a thrust ball bearing. The solutions of the equations of motion of the reciprocating mechanism along with the time dependent Reynolds equations for the lubricating film between piston and cylinder wall and lubricant films of the journal bearings are obtained simultaneously. The hydrodynamic forces of journal bearings are calculated using finite bearing model and G
m-bel boundary condition. And, a Newton-Raphson procedure was employed in solving the nonlinear equations of piston and crankshaft with a thrust ball bearing. The results explored the effects of design parameters on the frictional losses and dynamic stability of the compression mechanism.
Improvement of Low Temperature Fuel Characteristics by Pour Point Depressant
Lim, Young-Kwan ; Lee, Joung-Min ; Jeong, Choong-Sub ; Kim, Jong-Ryeol ; Yim, Eui-Soon ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 27, issue 2, 2011, Pages 109~114
DOI : 10.9725/kstle.2011.27.2.109
The low temperature characteristics of automotive diesel have been legally regulated due to the fact that solid particle in diesel at low temperature can cause severe problems in the vehicle. The biodiesel is well known for eco-friendly fuel, which is one of the most popular alternative petrodiesel, but it is easy to solidified at low temperature than petrodiesel at low temperature. For that reason, in this study, we investigated the low temperature fuel characteristics of diesel-biodiesel blends which were prepared to mix 6 different kinds of biodiesel to winter diesel fuel, respectively. Also, we confirmed to improve low temperature fuel characteristics by pour point depressant.