• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.694-697
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• 2005

The design of experiments are used for optimal design of formed tools to machine automobile bearing rubber seal die, which is classified into the high precision rubber mold. The clearance angle, rake angle and the length cutting edge are considered as the factors. The cutting force is selected to be a characteristic value and compared with the mean tool wear and life by repeated experiments. The design of the experiment is based on the repeated one-way factorial design, which finds the significance of the factors and the best level to predict the tool life by using ANOVA and regression.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.449-452
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• 2009

Ink-jet printed (IJP) self-aligned (SA) organic light emitting diodes (OLEDs) and its application to light emitting seal have investigated. Ink-jet printing of light emitting material is carried out onto transparent anode covered with insulating material. Laminated light emitting seal with SA IJP OLED without photo - lithographic process and any vacuum process, noncontact type electromagnetic power supply without electric power supply line, and light emitting tag with network type RF communication terminal by controlling display information were demonstrated.

• Tribology and Lubricants
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• v.11 no.3
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• pp.54-58
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• 1995

This paper deals with an experimental study on the dynamic behaviour of rubber oil seals when the interferences between the shaft and the seal lip as well as the dynamic eccentricities are present. The micro-separation of the sealing gap was observed with the aid of an image processing apparatus. The temperature of the seal lip edge, friction torque and the dynamic sealing gap profile are experimentally investigated for the initial interference and the shaft eccentricity. The data was simultaneously measured under the operation conditions. Experimental results show that, as the shaft speed is increased, the leakage of sealed fluids is increasing for a certain range of shaft speeds. The test data indicates that the shaft eccentricity clearly produces the gap separation between the shaft and the seal lip which is unable to follow the radial displacement of shaft as the shaft speed increases.

• Journal of the Korean Society of Safety
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• v.31 no.1
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• pp.19-24
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• 2016

Rubber parts are widely used in many applications such as dampers, shock absorbers, and seals used in railway and automotive industries. Much research has thus far been conducted on property estimation and life prediction of rubber parts. To predict the service life of rubber parts at room temperature, most prior work adopts the well-known Arrhenius model that needs the accelerated life test in high-temperature conditions. However, they may not reflect the actual conditions of use that rubber parts are usually used under a specific strain condition during long period of time. In this context, we propose a method for the life prediction of rubber parts in actual conditions of use. The proposed method is based on the accelerated life test using stress relaxation during which three relatively high elongation percentages (100%, 200%, and 300%) are applied to the rubber specimens. Rubber specimens were prepared in accordance with KS M 6518 standard and three stress relaxation testers were fabricated for actual experiments. Finally, a inverse power model for life prediction was derived from experimental results. The predicted life was compared with the actual test life for validation.

• Journal of the Korean Institute of Gas
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• v.9 no.1 s.26
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• pp.26-32
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• 2005

This paper presents the design safety of metal seals in pressure vessels. For a high-pressure vessel, a metal seal is usually used as a primary sealing, and an elastomeric rubber O-ring is adopted as a secondary sealing unit. The FEM computed results show that an aluminium material for sealing a gas leakage is superior to a steel one because of the thermal expansion rate. The deformation and stress distributions on the metal seal and pressure vessel structures are mainly dominated by transferred temperature compared to those of the gas pressure in which is supplied by an external pump. Thus, the temperature of a metal seal material should be restricted to under $200^{\circ}C$.

• Tribology and Lubricants
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• v.35 no.1
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• pp.52-58
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• 2019

In the case of high-voltage connectors applied to automobiles, waterproofing has become an important issue for the safety of automobiles. In this study, structural analysis is performed on silicone rubber-type waterproof seals used in the voltage connector. For the structural analysis, the tensile properties of the actual rubber seal are evaluated using a miniaturized tensile testing machine. The Mooney-Rivlin material constants of the rubber seal are determined as follows; $D_1=0$, $C_{01}=0.241$, $C_{10}=0.0142$. The analysis shows that the contact pressure at the top of the seal where the seal and male connector are in contact is approximately three times higher than that at the bottom of the seal where the seal and female connector are in contact. It is confirmed that the waterproofing performance of the rubber seal depends on the contact pressure of the seal bottom where the seal and female connector are in contact. The contact pressure for waterproofing is found to be 4.7 bar. The strain concentration of the curved part is attributed to excessive initial tension. Therefore, a redesign is recommended for uniform stress or strain distribution in the curved section of the seal in response to the stress relaxation problem due to permanent deformation.

• Tribology and Lubricants
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• v.22 no.6
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• pp.329-334
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• 2006

In CNG (Compressed natural gas) fuel supply line, whose main components are receptacle and check valve are used to charge high pressure gas to the tank of NGV (Natural gas vehicle). It is reported that the seal is separated occasionally form valve seat and results in blockage of gas flow. In this paper, MARC is used to investigate the reasons of seal separation and suggest design improvements. The static gas pressure distributions acting on the seal which calculated using FLUENT are considered to investigate accurate seal deformation behaviors. Deformed seal shapes are obtained for various amounts of seal interference and its location, gas pressure distributions and Young's modulus of the rubber used. The results showed that the reasons of seal separation problems are verified theoretically, and suggested examples of new design method. Therefore the present numerical methods can be applied in designing and performance analysis of rubber seals adopted in high pressure fluid machineries.

• Journal of Applied Reliability
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• v.7 no.1
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• pp.31-43
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• 2007

The function of O-ring seals is to prevent leakage during the service life of the components in which they are installed. The life prediction of O-ring is very important at various industry fields. Generally, to evaluated the long-term performance of O-ring in severe environments has applied a life prediction technique based on accelerated life test (ALT). In this work, Accelerated thermal aging test(l20, 130, 140, $150^{\circ}C$) of O-ring was applied for life prediction of O-ring. The property changes after thermal aging test was measured using TGA, DSC, FT - IR, Video Microscope and SEM. Shape parameter and life prediction were obtained using MINITAB program.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.5
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• pp.112-118
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• 2003

The friction coefficients of the rubber for clutch master cylinder were experimentally measured in this study. The cylindrical rubber samples for primary cup-seal and secondary cup-seal were tested against the aluminum or the steel plates of master cylinder housing under the various conditions of brake oil temperatures and normal loads. Dry sliding friction coefficients were also measured under various load conditions. The test revealed following results. First, the friction coefficient under fluid lubrication condition in general decreases, as the oil temperature or normal load increases. Second, the steel plate of low surface roughness yielded comparatively low friction coefficient on the range of 0.30∼0.67. On the other hand, the aluminum plate of high surface roughness yielded high friction coefficient on the range of 0.31∼1.15. Third, the friction coefficient of dry surface contact decreases as the normal load increases. This is contrary to the general principle of friction coefficient between metal plates.

• Tribology and Lubricants
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• v.34 no.5
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• pp.197-207
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• 2018

Thermal deterioration of fuel due to long-term storage influences engine performance and causes malfunctions. Fuel stability is usually evaluated via heat resistance and thermal stability during a brief heat shock at high temperature; storage stability in this scenario means that there is very little change in the quality of the fuel during long-term storage. In addition, rubber-based products such as oil seals, O-rings, and rubber hoses can influence the quality of the fuel. When these rubber products are in contact with fuel, they can swell, mechanically weaken, and occasionally crack, thus leaking low molar weight rubber and additives including plasticizer and antioxidant into the fuel to degrade its properties and shorten its useful lifetime. This study determines the thermal stabilities of three kinds of synthetic fuels by evaluating their low temperature kinematic viscosities, chemical composition changes via GC analyses, gross heat of combustion, and color changes. We evaluate the compression set of O-rings by immersing one NBR and two FKM rubber O-rings in the three synthetic fuel samples in airtight containers at variable storage temperatures for six months; from this, we estimate the lifetimes of the O-rings using the Power law model. There were very little changes in the chemical compositions and gross heat of combustion after six months of the experiment. The lifetimes are thus dependent on the materials of the rubber products, and in particular, the FKM O-ring was calculated to have a theoretical lifetime of 200 to 5,700 years. These results indicate that the synthetic fuels maintain their physical properties even after long-term storage at high temperatures, and the FKM O-ring is suitable for long-term sealing of these fuels.