• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.545-546
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• 2006

A problem of oil supply for a reciprocating compressor is very significant for an evaluation of reliability. Since a rotational motion of a crank shaft for the reciprocating compressor with small capacity is used for a power source of oil supply, a centrifugal force of the rotational shaft provides a stroke of oil inside the shaft like a centrifugal pump. The pumped oil rises following an inner wall and provided to a bearing passed through an oil supply hole at the side of the shaft for lubrication of the bearing. In this study, the amount of oil supply has been investigated by a numerical analysis for various conditions such as a shape of a groove, rpm of the compressor, and a shape of a flow channel. Also, a method of increasing oil supply for a low rpm has been studied so that the function can be improved for a variable condition.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.10a
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• pp.91-99
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• 1998

A correlation between the low-cycle fatigue life and the scuffing-failure life is demonstrated using the plastic strain in boundary lubricated sliding. Loadings proportional to hardness with three different lubricated conditions were used to evaluate the plastic strain. As the results of scuffing tests using vacuum pump oils in nitrogen gas, plastic strain shows 0.0062, and In the mineral oils and commercial engine oils in air, plastic strain show 0.0042 and 0.00092. Those are very useful to describe quantitatively the real lubricated sliding conditions, and are very effective to find the relation between the low-cycle fatigue life and the scuffing life.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.11a
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• pp.186-193
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• 2001

In the high pressure state, the leakage flow rate of hydraulics is one of serious problems and the great reason to decrease the volume efficiency. In this paper, I tried to clarify tribology characteristics for the slipper hydrostatic bearing in swash plate type axial piston pumps and motors by means of experiment . I measured the leakage flow rate between swash plate and piston shoe with change the supply pressure and oil temperature at a swash plate angle of 0。 . And I also investigated the slipper pocket pressure and calculated oil film thickness for theoretical method. So. 1 have analyzed the tribology characteristics of hydrostatic bearing for leakage flow rate and oil film thickness with oil temperature and supply pressure.

• Journal of the korean Society of Automotive Engineers
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• v.12 no.4
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• pp.35-46
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• 1990

The instantaneous friction in main bearings of a single cylinder diesel engine was determined by measuring the instantaneous angular velocity, calculating the resulting forces acting on the bearings, and solving the unsteady Reynolds equation in combination with the mobility method. The considered system consists of only the crankshaft with flywheel and oil pump. The thermal effects were not considered because of the short testing time. The tests were conducted using an electric start motor. The results indicated that when the bearing is not near equilibrium for very small speeds, simple film lubrication theories are not accurate. The details of grooves and unsteady terms in the Reynolds equation cannot be ignored for increasing efficiency of instantaneous friction calculation of the engine bearings. The effects of speed on instantaneous friction and energy lost in friction were determined.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.745-746
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• 2006

This lecture introduces new press, adapter and control concepts to size multi-level sintered components. The essential thing here is that the advantages of the multi-plate technology have been applied to the sizing adapter concept. Thus, the new concept meets the demands for a modern P/M manufacture and offers sufficient potential to size any future, complex sintered components such as synchronizer hubs, oil pump wheels and VCT parts with highest precision. Furthermore, it outlines a new flexible concept for the parts transfer, including feeding, orientation and lubrication while responding to the high demands on process stability and short change-over times.

• Journal of Drive and Control
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• v.14 no.1
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• pp.29-34
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• 2017

This study analyzed a life test method for a power take-off (PTO) gearbox. An engine transfers mechanical power (rotation and torque) to a hydraulic pump through a PTO Gearbox with one input shaft and three output shafts. PTO gear box durability under high loads over long time periods was tested using dynamometers. In order to reflect the rated operating conditions, power must be distributed to each output shaft, and experiments were conducted under various conditions to verify the characteristics of the distributed power. An accelerated life test was designed using speed and torque as acceleration factors. Also, efficiency tests were conducted under various load conditions. Also, a lubrication oil composition analysis was performed to analyze gearbox wear status.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1994.06b
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• pp.49-53
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• 1994

베인형 펌프, 모터 등의 마찰, 마모특성에 관해서 많은 연구가 있었으나, 베인펌프는 구조로부터의 제약이 많기 때문에, 대용량, 고압, 고속화라는 일련의 요구를 만족시키는 것이 쉽지 않아, 그 요구에 부응하기 위해 지금까지의 연구가 내마모성 작동유, 표면처리 기술, 특수 베인기구등의 개발을 제약에 부딪칠 때마다 필요에 따라 한결같이 경험적으로 이루어졌으며, 측정에 대한 면에서도 동적 조건 하에서의 측정은 거의 없으며, 해석에 관해서도 일반성이 상당히 결여된 상태라 할 수 있다. 따라서 본 연구에서는 유압 베인펌프의 베인과 캠링간의 접동 모델로써 동적 마찰 실험장치를 제작하여, 베인 선단의 마찰력을 측정하고 이를 기초로 하여 실기 유압 베인펌프의 베인과 켐링내면간의 접동부에 관한 마찰특성을 추정하는 것을 목적으로 하였다.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2004.11a
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• pp.255-260
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• 2004

Recently, the technologies related to the swash plate type oil hydraulic piston pump are requiring extreme technologies to overcome the limit of high efficiency in cope with high speed and pressure, and are devoted to compact the unit, to gain low noise level, and to adopt electronic technologies, and the question regarding to maximize the mechanical efficiency, that is, to minimize the torque loss by minimizing the leakage loss in the relative sliding region but these are in trade-off relation that tribological responding is very difficult. Cylinder block-valve pate in high speed relative sliding motion has the characteristics that should be extremely controlled for the optimization of these leakage loss and mechanical efficiency, and pressure resistance designing of them is important for high pressure performance. But, studies on the stress analysis of these parts have not been performed briskly, so in this paper the stress distribution and the region where the highest displacement appears are described through the static stress analysis using CATIA V5. Through the future studies on these theme, it has the purpose of finding the suitable materials for the other parts as well as cylinder block and valve plate, in cope with high pressure operation through the stress analysis with the most similar conditions for the practical operation.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.381-382
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• 2002

The Fluid film between the valve plate and the cylinder block was measured by use of a gap sensor and the mercury-cell slip ring unit under real working conditions. During the operating periods, experiments with discharge pressure, revolution speed, and valve geometry was carried out for the fluid film on the valve plate. To investigate the effect of the valve shape, we designed two valve plates each having a different shape; the first valve plate was a plane valve plate. while the second valve plate was a spherical valve plate. It was noted that these two valve plates observed different aspects of the fluid film characteristics between the cylinder block and the valve plate. The leakage flow rate and the shan torque were also investigated in order to clarify the difference between these two types of valve plates. From the results of this study. we found that the spherical valve plate estimated good fluid film patterns and performance more than the other valve plate in oil hydraulic axial piston pumps.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2004.11a
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• pp.158-161
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• 2004

In recent, the automotive number of korea has risen above 14millions vehicles. The automotive was settled down goods haying to live. In a flood of this automotive the accuracy diagnosis for the vehicle certainly need for people referencing car. To do this diagnosis, the researcher has to experience many example in the field and need to system them. Expecially, the study for failure of the engine nearly research in the korea. When moving parts of engine no problem. In order to work, the engine must operate normality state. In this paper the purpose study the failure for the tribological example of engine.