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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
Selecting the target year
Development of an Engine Oil Quality Monitoring System
Chun, Sang-Myung ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 27, issue 3, 2011, Pages 125~133
DOI : 10.9725/kstle.2011.27.3.125
The purpose of this study is to develop an engine oil quality monitoring system to warn the abnormal condition of engine oil. To do this, first of all, it is needed a personal controller development to measure the capacitance of a pre-developed engine oil deterioration detection sensor integrated with an oil filter. To measure the capacitance of engine oil in the sensor, it is used the way measuring the electric charging time in a capacitor by impressing DC volt. This method has merits on cost and signal stability. The measured capacitance is compensated by comparing with the one measured by an impedance analyzer. Also, using the dielectric constant gained by an impedance analyzer, the calculating equation of the dielectric constant of engine oil related with the currently developed sensor is decided. Then, the deterioration degree of engine oil is estimated according to the change rate of dielectric constant between green oil and used oil. Finally, using this dielectric constant information together with engine oil temperature and pressure, the currently developed engine oil quality monitoring system is to tell the abnormal state of engine oil.
A Study on the Effects of Contaminant Types on the Wear Degradation Characteristics in Internal Gear Pumps
Shin, Jung-Hun ; Ji, Kyung-Ryeol ; Kim, Hyoung-Eui ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 27, issue 3, 2011, Pages 134~139
DOI : 10.9725/kstle.2011.27.3.134
The mechanical equipments which are exposed to impure environment undergo significant reductions in their own lifetimes. Several environmental test procedures have been developed to analyze these phenomena. Moreover in the industry to require shorter development duration, accelerated life testers artificially add test containments into machines. In this research JIS Z 8901 test powder was added into internal gear pumps which are used as oil pumps in vehicles and thus the effects of the addition on the degradation of the pumps were examined. Three kinds of contaminants were selected. Two of the contaminants are identical in particle size but different in the composition of the ingredients. The other pair have identical ingredients and composition but different particle size. The quantity of contaminants was also an interesting factor in this study. The results show that each JIS contaminant caused notable degradation in the discharge flow characteristic of pumps while friction torque degradation did not have any tendency. Finally leakage rates were deduced and equivalent wear volume ratios were calculated.
Development of a Miniature Pendular Type Impact Testing Machine Using a Magnetic Powder Brake
You, In-Dong ; Lee, Man-Suk ; Kim, Ho-Kyung ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 27, issue 3, 2011, Pages 140~146
DOI : 10.9725/kstle.2011.27.3.140
A miniature pendular type impact testing machine was designed and developed, adopting a magnetic powder brake in order to investigate tensile and shear behavior of a small solder ball at high speed. In this testing system, the potential energy of the pendulum is transferred into the impact energy during its drop. Then, the impact energy is transmitted through the striker which is connected to the push rods to push the specimen for tensile loading. The tensile behavior of lead-free solder ball in diameter of 760
was successfully investigated in a speed range of 0.15 m/s~1.25 m/s using this designed device. The maximum tensile strength of the solder joint decreases with the loading speed in the testing condition. The maximum tensile strength of the joint was 56 MPa in the low speed region.
A Study on the Allowable Stress of TiN Coating During Repeated Sliding Condition by In-situ System
Moon, Bong-Ho ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 27, issue 3, 2011, Pages 147~155
DOI : 10.9725/kstle.2011.27.3.147
The ceramic coatings are excellent materials of cutting tools and sliding parts. To evaluate the wear characteristics of very thin ceramic coated layer, it is very important to investigate its wear process microscopically. An effective method for investigating the wear of a thin layer is the observation of wear process in microscopic detail using in-situ system. In this study, using the SEM Tribosystem as in-situ system, the microscopic wear mode of TiN coatings was investigated in repeated sliding. As results, four modes were observed for TiN coatings: Ploughing, powder formation, flake formation and coating delimitation. The observation of the microscopic wear by in-situ system can clarify the allowable stress of TiN coating.
Microwave Rectangular Waveguide Measurement of the Engine Oil Dielectric Constant
Kim, Ki-Hoon ; Kim, Young-Ju ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 27, issue 3, 2011, Pages 156~161
DOI : 10.9725/kstle.2011.27.3.156
The rectangular waveguide technique can be used to measure the complex permittivity of dielectric material of various thickness and cross section. This paper presents the analysis system of engine oil permittivity at which deterioration of engine oil is measured at the X-band(8-12.5 GHz). The middle of the rectangular waveguide has engine oil case and is connected with VNA(Vector Network Analyzer) for the measurement of the transmission
and then the permittivity is extracted. The deterioration of engine oil is proved by the comparison with both the extracted data and reference data. As the additional research, This paper suggest that an accurate permittivity is considered by not only the wave guide length but the air gap between oil case and the waveguide.
Load Distribution, Contact and Fatigue Life Analysis for Ball Bearing of Under Moment Load
Kim, Young-Kuk ; Moon, Seok-Man ; Kim, Tae-Wan ; Cho, Yong-Joo ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 27, issue 3, 2011, Pages 162~166
DOI : 10.9725/kstle.2011.27.3.162
This study is aimed to predict the fatigue life for bearings under combined radial, thrust and moment load. In order to do this, a series of simulation such as bearing load distribution, initial surface stress, subsurface stress and fatigue analysis is needed. And using the bearing's material fatigue property we can predict fatigue life for ball bearing.
Permanent Magnet Combined Thrust Magnetic Bearing Simulation and Experiment
Park, Byeong-Cheol ; Jung, Se-Yong ; Han, Sang-Chul ; Lee, Jeong-Phil ; Han, Young-Hee ; Park, Byung-Jun ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 27, issue 3, 2011, Pages 167~173
DOI : 10.9725/kstle.2011.27.3.167
In this paper, an actuator model of the thrust magnetic bearing for the flywheel energy storage is derived using magnetic circuit theory. And we compared this result with finite element magnetic field analysis result. Based on the actuator model, we made a simulation model of the thrust magnetic bearing system. We showed the closed loop transfer function and sensitivity function of the thrust magnetic bearing system using both the simulation model and the experiment. The experimental result at rotation velocity 18,000rpm of thrust magnetic bearing system is included.