• Proceedings of the KSR Conference
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• 2004.10a
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• pp.601-605
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• 2004

Railway wheel is the important element of rolling-stock in the viewpoint of running safety. Thus, the material properties of strength, fatigue crack, durability are needed, and the standards for test and criteria of whee] are established to guarantee quality of wheel. In the meantime, the suppliers for wheel in domestic are varied from domestic monopolization to diverse company of China, Russia, Czech Republic, etc. The uniform quality of wheel is important from a maintenance point of view. We collected wheel samples of diverse vendors to analyze the uniformity of wheel on the basis of korea national standard. We tested material properties and analyzed the test data statistically.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.914-917
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• 2000

Application of ceramics, carbide, ferrite has grown considerably due to significant improvement in their mechanical properties such as light weight, chemical stability , super wear resistance and electronical. Despite these character, the me of advanced material has not increased because of poor machinability. The method of using of metal bond wheel was proposed. But it is difficult that metal bond wheel can be dressed. Recently, the technology of in-process electrolytic dressing is developed to solve this problem. This method need wheel for electrolytic dressing, power supply and electrolyte. But development of wheel for electrolytic dressing is the most need. The aim of this study is development of wheel for electrolytic and appraisement of CIB-diamond lapping wheel

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.858-861
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• 2000

Application of ceramics, carbide, ferrite has grown considerably due to significant improvement in their mechanical properties such as light weight chemical stability super wear resistance and electronical. Despite these character, the use of hi-tech material has not increased because of poor machinability. The method of using of metal bond wheel was proposed. But it is difficult that metal bond wheel can be dressed. Recently, the technology of in-process electrolytic dressing is developed to solve this problem. This method need wheel for electrolytic dressing, power supply and electrolyte. But development of wheel for electrolytic dressing is the most need. The aim of this study is development of wheel for electrolytic and appraisement of CIB-diamond lapping wheel

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.925-929
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• 2001

Ultra-abrasives such as diamond and CBN have used to maintain accuracy and form deviation for superalloy etc. This study contains the dry cylindrical grinding of metals with Vitrified-bond CBN wheel and Resinoid-bond CBN wheel. For various conditions of grinding speed, workpiece speed, grinding depth and feed speed of table, the grinding resistance, the surface roughness, and the material removal are measured and discussed.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.315-320
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• 2001

Ultra-abrasives such as diamond and CBN have used to maintain accuracy and form deviation for superalloy etc. This study contains the dry cylindrical grinding of metals with Vitrified-bond CBN wheel and Resinoid-bond CBN wheel. For various condition of grinding speed, workpiece speed, grinding depth and feed speed of table, the grinding resistance, the surface roughness, and material removal are measured and discussed.

• Journal of Power System Engineering
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• v.21 no.2
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• pp.41-47
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• 2017

Boron steel (51B20) was cold forged using by new designed dies to apply for automotive aluminum wheel nut. The formability and mechanical properties of boron steel were compared with carbon steel(S45C) which has been used up to date for the wheel nut material. The formability was investigated on the dies designed with various types of punch nose using by FEM. The metal flow and compressive stress on the dies during cold forging were investigated and compared each other. The forging process with a new designed die showed the improved metal flow with a reduced forging load which resulted in the significant increase of the die life. It was recommended that the carbon steel for automotive wheel nut material could be substituted by the boron steel.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.9
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• pp.2866-2874
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• 1996

In the grinding of difficult-to-materials, the major problmes of conventional grinding are grinding burn, wheel wear, grinding surface crack, loading and glazing, When a conventioanl grinding wheel is used, wheel wear and grinding surface crack easily occur in low heat conductive material and annealed steel. Intermittent grinding is suitable for diffcult-to-matrical such as stainless steel, titanium alloy, aluminum alloy and copper alloy. The purpose of this paper is to develop a new type intermittent wheel of the grinding system for improving the problem of stainless steel grinding, to observe the effect of intermittent grinding on surface quality and grinding characteristics of stainless steel grinding using intermittent grinding wheel. The characteristics of intermittent grinding system improve surface quality, low grinding temperature and low loading.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.1 s.178
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• pp.145-151
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• 2006

Wheel bearing unit has been exclusively applied to car wheel supporting device. The seal for wheel bearing is required to have both high sealing effects and low reaction forces because wheel bearing are operated on adverse environmental conditions such as mud and splash water. High sealing effects are for the protection of bearing ball wear from dust influx. In order to ensure high sealing effects, it is a easiest way to increase contact force which are affected by geometric characteristics, material properties and interferences between seal and inner bearing but induces higher wear phenomena. Interferences in all variables are most important factor to determine the performance of wheel bearing. In this study, optimization of interference amount was performed with finite element analysis with commercial code ABAQUS. For the sake of finite element analysis, tensile tests of rubber material were conducted and governing equation of nonlinear behavior was achieved. Hock-up bearing was manufactured with optimized interference amount. Results of torque and mud spray tests using this bearing unit are performed. Less torque and moisture influx of bearing with optimized interference amount is evidence to validity of this study.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.1009-1014
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• 1997

The small material removal rate of elastic emission machinong (EEM) becomes a serious problem due to using fine powder particles for obtaining finished of high quality. If a cylindrical polyurethane-wheel is used as a tool for accelerating powder particles, the efficiency of machining may be increased through enlarging the machining regionand increasing the surface velocity of the wheel. If these analyicl results are compared with experimental ones, characteristics of EEM using polyurethan-wheel can be clarified. In this study, effects of EEM using cylindrical polyurethane-wheel on the surface roughness and the material removal rate were verified through polishing of the brittle material under various conditions. The high-efficient polishing of silicon wafer has been also carried out using this method.

• 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.