• Journal of Applied Reliability
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• v.9 no.4
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• pp.275-290
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• 2009

This paper considers accelerated thermal degradation tests which are performed for rubber seal materials used for undersea tunnels constructed by immersion method. Three types of rubber seals are tested; rubber expansion seal, omega seal, and shock absorber hose. Main ingredient of rubber expansion seal is EPDM(Ethylene Propylene Diene Monomer) and that of both omega seal and shock absorber hose is SBR(Styrene Butadiene Rubber). The accelerated stress is temperature and an Arrhenius model is introduced to describe the relationship between the lifetime and the stress. From the accelerated degradation tests, dominant failure mode of the rubber seals is found to be the loss of elongation. The lifetime distribution and the service life of the rubber seals at use condition are estimated from the test results. The acceleration factor for three types of rubber seals are also investigated.

• Tribology and Lubricants
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• v.12 no.1
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• pp.42-46
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• 1996

This paper deals with a numerical study of the dynamic response of rubber oil seals for rotating shaft when interference as well as static and dynamic eccentricities are present. In loss of contact conditions the dynamic curve of oil seals is numerically simulated using the FEM package MSC/NASTRAN. The direct integration method is selected to analyze the time domain response of the seal lip-shaft contact. The computed results based on the experimental data indicate that the increased rotating speed may produce the gap separation between lip edge of rubber seals and shaft. These results will be very useful in predicting the dynamic leakage due to contact behaviors of rubber oil seals under dynamic conditions.

• Tribology and Lubricants
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• v.14 no.2
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• pp.21-25
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• 1998

This paper presents the experimental results of the friction characteristics of double liptype oil seals which show an improvement in sealing performance over single lip-type oil seals. The major differences between two oil seals are the number of contact lip, and seal materials; Nitrile Butadine Rubber(NBR) and urethane rubber. The measured results show that the friction torques of double lip seals show 12-17% increases compared with those of single lip-type seals. But the sealing performance and service life of double lip oil seals have been increased and stabilized due to an optimized design of the seal lip and material properties.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.04a
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• pp.307-313
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• 1998

This paper presents the experimental results of the friction characteristics of double lip-type oil seals which show an improvement in sealing performance over single lip-type oil seals. The major differences between two oil seals are the number of contact lip and seal materials; Nitrile Butadine Rubber(NBR) and urethane rubber. The measured results show that the friction torque of double lip seals shows 12-17% increases compared with those of single lip-type seals. But the sealing performance and service life of double tip oil seals have been increased and stabilized due to an optimized design of the seal lip and material properties.

• Journal of Power System Engineering
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• v.21 no.6
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• pp.86-93
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• 2017

Silicone rubber wire seals are widely used in automotive connector systems for waterproofing and so on. The purpose of this paper is to predict and evaluate the sealing performance of wire seals using finite element analysis. The material properties of the rubber seals were determined by the curve fitting of uniaxial tensile test and equibiaxial tensile test data. The response surface method was used to determine the optimum shape of the wire seal. In order to verify the accuracy and reliability of the simulations on the deformation prediction of wire seals, experiments were also carried out.

• Journal of Advanced Marine Engineering and Technology
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• v.15 no.5
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• pp.47-54
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• 1991

The lip seals widely used nowadays in stern tube sealing system of ships have radial sealing contact with shafts or liners, on the other hand the face seals of stern tube sealing system have axial sealing contact with seat. Because of axial sealing contact, the face seals have a large number of merits such as durability of life, simplicity of structure, easy fitting and replacement, etc. In this paper, for the purpose of development of face seals, the fundamental properties of axial sealing contact were analyzed and a trial face seal was designed and manufactured using N.B.R. rubber and Thordon which is widely used for bearing materials. The seal proper of trial face seal was made from N.B.R. rubber and the face insert was made from Thordon, thermosetting resins which are three dimensional, cross linked condensation polylmers. The performance test of trial face seal was carried out on the test bench which was specially designed and manufactured. The results were satisfactory enough to be used in practical stern tube sealing system.

• Tribology and Lubricants
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• v.35 no.5
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• pp.267-273
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• 2019

Wheel bearings are important automotive parts that bear the vehicle weight and translate rotation motion; in addition, their seals are components that prevent grease leakage and foreign material from entering from the outside of the bearings. Recently, as the need for electric vehicles and eco-friendly vehicles has been emerging, the reduction in fuel consumption and $CO_2$ emissions are becoming the most important issues for automobile manufacturers. In the case of wheel bearings, seals are a key part of drag torque. In this study, we investigate the prediction of the drag torque taking into consideration the hyperelastic and viscoelastic material properties of automotive wheel bearing seals. Numerical analysis based on the finite element method is conducted for the deformation analyses of the seals. To improve the reliability of the rubber seal analysis, three types of rubber material properties are considered, and analysis is conducted using the hyperelastic material properties. Viscoelastic material property tests are also conducted. Deformation analysis considering the hyperelastic and viscoelastic material properties is performed, and the effects of the viscoelastic material properties are compared with the results obtained by the consideration of the hyperelastic material properties. As a result of these analyses, the drag torque is 0.29 Nm when the hyperelastic characteristics are taken into account, and the drag torque is 0.27 Nm when both the hyperelastic and viscoelastic characteristics are taken into account. Therefore, it is determined that the analysis considering both hyperelastic and viscoelastic characteristics must be performed because of its reliability in predicting the drag torque of the rubber seals.

• Tribology and Lubricants
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• v.10 no.2
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• pp.39-42
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• 1994

This paper deals with the distributions of the contact stress in oil seals. The distributions of the contact stress due to the temperature effects are analyzed for various values of the interference for a nitrile rubber seal. The calculated FEM results show that the relative maximum stresses occur at the contacting area against the shaft, the flex zone, and the contacting area of the garter spring grooves. Using the coupled temperature-stress FEM a nalysis, the contact force of a radial lip seal with and without the garter spring are studied as a function of shaft diameter. The calculated results of mechanical analysis show good correspondence with those of the coupled thermal-mechanical analysis method except small values of the interference. And the calculated results indicated that the thermal stresses only have a very minor influence on the deformed shape of the lip seal as the interference increases. But the coupled temperature-stress analysis will be very useful tool to predict the contact behaviors of rubber lip seals for small values of the interference.

• Tribology and Lubricants
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• v.9 no.1
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• pp.32-37
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• 1993

The equations are derived for the evaluation of the axial contact forces. The contact forces of rubber seals are analyzed as a function of the ratio of real contact length, the thickness of seal lip, the inclined angle of seal lip, and the interference between the edge of seal lip and the rotating inner ring. The experimental apparatus is developed for the test of seal lip contact force. The data for designing rubber seals are presented in terms of the ratio of real contact length, initial inclined lip angle, lip thickness. and the interference. The results obtained from the derived equation for the contact force are in good agreement with the experimental results.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.12 s.189
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• pp.80-87
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• 2006

Seals are usually made from elastomer, a kind of rubber, and it has the non-linearity and hyper-elasticity. U-type seals are used to prevent the leakage of internal fluid sealed in hydraulic actuator because they have more excellent performance than O-rings or rectangular seals. As a core part of hydraulic actuator, U-type seal gives much effect on performance and reliability of actuator. This study considers an NBR U-type seal under high pressure of a hydraulic actuator, and provides its deformation, stress-strain characteristic and contact force using the non-linear finite element analysis. Analysis results are compared with the experimental ones performed by the self-developed testing equipment. Verification result shows that this study presents a good application process for the effective design of U-type seals under high operation pressure.