• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2002.10b
• /
• pp.269-270
• /
• 2002

Antiwear(AW) properties of phoshphonic acid derivatives for trimethylolpropane (TMP) esters were investigated under boundary conditions. AW effect of dialkyl phosphonates depends on polarity of base fluid. They provide good AW performance in less polar TMP esters, whereas their AW effect is not sufficient in polar TMP esters. Amine salts of phosphonic acid were developed as new AW additiνe system for TMP esters. They provide excellent AW performance even in polar TMP esters.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2005.10a
• /
• pp.67-83
• /
• 2005

[ $\blacklozenge$ ] Farm equipment market very cyclic - weather, economic factors, import/export markets $\blacklozenge$ Mergers of companies continuing $\blacklozenge$ Major Tractor OEMs have lubricant specifications $\blacksquare$ Their own house branded THF $\blacksquare$ Constant review reflecting the changes in equipment $\blacksquare$ Less interest in approving outside additives/oils for others $\blacklozenge$ Future THF lubricant market $\blacksquare$ ' Universal' THF may five way to individual products for each OEM $\blacksquare$ Sumps are getting smaller $\blacksquare$ Increased use of hydraulic system vs. mechanical $\blacklozenge$ Additive companies will need to meet many challenges

• Journal of the Korean Society for Precision Engineering
• /
• v.23 no.6 s.183
• /
• pp.37-43
• /
• 2006

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2004.11a
• /
• pp.139-142
• /
• 2004

The object of the present work is the acoustic emission energy analysis of subambient pressure tri-pad slider. Head/disk interaction during start/stop and constant speed were detected by using acoustic emission (AE) test system The frequency spectrum analysis is performed using the AE signal obtained during the head/disk interaction Natural frequency analysis was performed using Ansys program. Acoustic emission energy was calculated for the slider modes.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1996.10a
• /
• pp.176-182
• /
• 1996

This paper describes an empherical equation which is to predict the engine condition of the supersonic aircraft. The equation, which is a function of running time of engine and engine oil, is derived from the trend analysis of JOAP data. Qualitative analysis is carried out to make up for the weak points in the current JOAP system. Also wear debris collected from the abnormal engine is analyzed by EDS to detect the damaged parts of engine.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1998.04a
• /
• pp.335-341
• /
• 1998

In this study, the dynamic characteritics in various loading methods for wear tester were investigated experimentally. As for the dead-weight, the pneumatic, and the hydraulic method, the load control performance against external disturbances was estimated under the several loading conditions like the different sliding speed, the varied normal load, and the misaligument. The hydraulic loading method showed the most stable loading performance of all the loading methods in the experiment.

• Tribology and Lubricants
• /
• v.11 no.1
• /
• pp.44-49
• /
• 1995

Friction characteristic of an engine crankshaft bearing is affected by revolution speed, applied loads, and viscosity of lubrication. So, experimental investigation is required to observe the friction characteristics using these factors. Hydraulic cylinder, servo controller system which can be modified the applied load, and test rig for the observation of the characteristics of engine crankshaft bearings were designed and fabricated, and some experiments were performed. Friction torque, journal locus and circumferential temperature variation of crankshaft bearing were measured according to applied load, revolution speed, and oil inlet temperature.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1998.04a
• /
• pp.241-245
• /
• 1998

The traditional approach is to characterize the behavior and performance of fluid film hydrodynamic journal bearings by means of linearized bearing analysis. The objective of this paper is to examine the nonlinear characteristics of the journal bearing when an external sinusoidal shock is given to the system. The oil film force is obtained by solving the finite width Reynolds equation at each time step by the solution of the column method. Frequency response functions obtained from both linear and nonlinear bearing simulations are compared with each other.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.10a
• /
• pp.395-396
• /
• 2006

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1998.10a
• /
• pp.203-211
• /
• 1998

ER clutch is a device using electro-rheological fluid which is one of so called intelligent materials. Power transmission behavior of an ER clutch can be controlled by electrical field applied tb the fluid. In this work, a new type of servomechanism is developed with two ER clutchs, driven by two electrical motors rotating in reverse directions. The concentric cylinder type ER clutch is operated by PID control. The system shows good angular position control characteristics with respect to sinusoidal and square inputs.