• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.5
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• pp.81-87
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• 2002

The existing compressor steel seal used in automotive air-conditioner has the problem of oil leakage and deterioration in shielding performance, due to the abrasion and corrosion of the material. A new type of polymer resin seal studied in this research has the characteristics of high anti-abrasiveness and anti-corrosiveness, which can oversome the defects of the steel seal. In addition, the seal needs lower manufacturing cost and is appropriate to mass production, because it is made by the injection molding method requiring no mechanical processing. The profile generation program for seal mold has been developed using the gradient method, and the molding characteristics of the seal have analyzed through the flow analysis and the warpage analysis. The program has been verified by comparing the analysis results with the measured data of the test product. The research might be said to provide the basic method to produce the polymer resin seals with various types and dimensions.

• International Journal of Precision Engineering and Manufacturing
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• v.7 no.4
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• pp.23-27
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• 2006

Rubber is used in many industrial products, such as hoses, rubber belts, and oil seals. In particular, more than 200 rubber parts are used in automobiles. The design technology of these parts is largely dependent on field experience, which leads to lengthy and expensive developing procedures. However, with the help of recent developments in nonlinear computer analysis, new rubber products can be developed at low cost. In this study, rubber injection molding design variables, such as location and number of gates, were optimized using computer-aided engineering with the cross-WLF equation to produce CLIP rubber products made from ethylene propylene diene monomer(EPDM). The validity of the proposed design was evaluated by comparison with actual forming results.

• Journal of Aerospace System Engineering
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• v.6 no.2
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• pp.35-41
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• 2012

A reciprocating engine installed on a normal category airplane shall be effectively cooled by air flown through the engine compartment. A airplane powerplant designer has to design cooling air inlets, baffles, seals, and outlets to maintain cylinder head temperatures and oil temperature under the limits, and show compliance with appropriate airworthiness standard. In this study, cooling designs of the installed engine and compliance requirements applicable to the cooling designs were reviewed, and engine cooling flight test results were evaluated for design changes. Engine cooling certification test will be conducted in a next step.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.4
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• pp.473-485
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• 2015

The problems for non-rotating of a disc cutter proceed from the faults in inner parts of the disc cutter such as the leak of hydraulic fluid, the intrusion of tunnel mucks and water, overloading, overheating, poor assembly and substandard material. The rotating of a disc cutter is an indicator to show that the inner parts of disc cutter is operable, although the rotational torque depends on the extent of the damage. Therefore, the key in the problems for non-rotating of disc cutter is to maintain that the tapered roller bearings are working properly. This study aims to investigate the inner parts disassembled from disc cutters applied to the field tests in order to help decision for reuse of the disc cutters. As results, surface finishing to remove the scratch on the load zone of the hubs is needed, with the intent to reuse a hub. And the investigation of lapping surface by optical microscope of floating seals and the contamination test of oil need to be performed for reuse of a disc cutter. Especially, the analysis results show that the floating seals play a key role in the normal operation of bearings. There is nothing significant to report in the rest parts such as bearing, shaft, seal retainers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.579-584
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• 2017

The damper oil seal of a high-speed railway vehicle is made from nitrile butadiene rubber (NBR) in order to prevent lubricant from leaking into the damper and to stop harmful contaminants from entering the external environment while in service. Oil leakage through the seal primarily occurs from fatigue failure of the damper. Cumulative damage of the seal occurs due to the contact force between the rod and the rubber during movement due to track irregularities and cants, among other factors. Thus, the design of the oil seal should minimize the maximum principal strain at weak points. In this study, the optimal cross section of the damper oil seal was found using the multi-island genetic algorithm method to improve the durability of the damper. The optimal shape of the oil seal was derived using process automation and design optimization software. Nonlinear material properties for finite element analysis (FEA) of the rubber were determined by Marlow's model. The nonlinear FEA confirmed that the maximum principal strain at the oil leakage point was decreased 24% between the initial design and the optimum design.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.3
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• pp.165-171
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• 2023

The rotary joint connecting the upper and lower structures of construction machinery and special vehicles transmits hydraulic pressure as the shaft and housing rotate, and multiple seals are assembled to prevent oil leakage into the oil flow channel. Because the seal material is rigid and difficult to assemble, we sought a method to assemble it after cutting. The shapes of the cutting surface are L-shaped and / shaped, and the leakage standard when hydraulic pressure is applied is the contact pressure generated on the cutting surface. The structure and material of the seal are composed of a double elastomer, and nonlinear contact structural analysis is performed when only the high-rigidity PE material is cut. Studies have shown that the shorter the cutting length, the better the leakage prevention and the higher the possibility of leakage to the bottom surface where NBR and PE come into contact rather than the top surface where the PE and the housing come into contact.

• Tribology and Lubricants
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• v.40 no.2
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• pp.54-60
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• 2024

This study experimentally identifies the effects of end shape, clearance, total damper length, journal eccentricity ratio, oil supply pressure, and oil flow rate on the damping coefficient of a squeeze film damper (SFD) with piston ring seal ends and a central groove. The SFD is composed of a lubricating fluid flowing between the outer race of a rolling element bearing and cartridge, along with an anti-rotation pin to prevent the rotation of the outer race. The device provides additional viscous damping to a rotating system. Additionally, piston ring seals attached at both ends of the damper increase the damping coefficient of the rotating system by reducing oil leakage. Because these different design conditions affect the damping coefficient of an SFD, we perform experiments including different conditions. Tests show that the damping coefficient increases significantly in the SFD with piston ring seal ends compared with the SFD with open ends. The damping coefficient also increases with increasing total damper length and journal eccentricity ratio, and decreases with increasing clearance. Additionally, in contrast to the trend observed for the SFD with open ends, the damping coefficient for the SFD with piston ring seal ends increases with increasing supply pressure and flow rate as the frequency decreases but shows consistent results as the frequency increases.

• Journal of Advanced Marine Engineering and Technology
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• v.15 no.4
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• pp.29-45
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• 1991

Lip type stern tube sealing systems have used in almost all the middle or large ships which are being constructed in these days. It seems that the pressure fluctuation of the seal ring interspace, the cross-section profile and the materials quality of the seal rings have great effects on the sealing fuction of this sealing system. In this paper, the mechanical movement of lip seal ring which plays the most important role in stern tube sealing system and the possibility of leakage caused by pressure fluctuation are studied by theory and experiment. Using the finite element method for the axi-symetric object which receives the torsional load, the displacement and stress analysis of the seal rings, and also the possibility of crack occurance is checked by theoretical analysis. If the force which seal ring lip periphery receives is too small, there will be the possibility of leakage caused by the pressure fluctuation of the seal ring interspace, and if this force is too large, the frictional force between the seal ring and the liner will become problematical. The possibility of leakage caused by hardening of seal ring materials and creep phenomena of tested seal rings are also examined. The trial seal rings were designed and manufactured using the program of displacement and stress analysis developed in this study and the experimental apparatus to test the trial seal rings was also designed and manufactured. This trial seal rings were fitted in the experimental apparatus which was made in the same form as an actual stern tube. The one side of this apparatus was filled with sea water and the other side of it was filled with the lubricating oil. The leakage of oil and sea water was checked and the temperature was measured, rotating the propeller shaft at the constant velocity by D.C. motor. It was proved that the trial seal rings made in Viton rubber functioned excellenty but the trial seal rings made in N.B.R. rubber had problem in its durability.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.344-349
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• 2012

This paper presents a new small-sized damper featuring magneto-rheological (MR) fluid which can be applied to vibration control system. The proposed MR damper consists of cylinder, piston, a couple of bearings, oil-seals and magnetic circuit which has two coils. In this damper, approximately 5cc of MR fluid is used. The damping force of the MR damper is designed to be followed by linear shear-mode Bingham-plastic model. In order to verify the performance of the MR damper, an experimental apparatus is established. In the experimental test, the damping force of the MR damper is measured with respect to time, displacement and velocity. In addition, the time response of MR damper is measured when 1A of step current is applied. Finally, The proposed small MR damper is applied to vibration control. In this process, a simple 1-DOF system is modeled and controlled using PID controller.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.11
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• pp.1121-1127
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• 2012

This paper presents a new small-sized damper featuring magneto-rheological(MR) fluid which can be applied to vibration control system. The proposed MR damper consists of cylinder, piston, a couple of bearings, oil-seals and magnetic circuit which has two coils. In this damper, approximately 5cc of MR fluid is used. The damping force of the MR damper is designed to be followed by linear shear-mode Bingham-plastic model. In order to verify the performance of the MR damper, an experimental apparatus is established. In the experimental test, the damping force of the MR damper is measured with respect to time, displacement and velocity. In addition, the time response of MR damper is measured when 1A of step current is applied. Finally, the proposed small MR damper is applied to vibration control. In this process, a simple 1-DOF system is modeled and controlled using PID controller.