• 한국도로학회논문집
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• 제7권2호
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• pp.97-107
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• 2005

반복주행시험에서 얻은 침하깊이와 동적안정도는 아스팔트 혼합물의 소성변형 저항성 평가를 위하여 널리 사용되고 있다. 하지만 바퀴의 재질에 따라 다르게 얻어지는 실정이다. 따라서 본 연구는 반복주행시험시 핵심요소라 할 수 있는 바퀴의 재질에 대하여 연구하였다. 이를 위하여 2종류(7.5mm, 15mm)의 고무바퀴와 고무를 씌우지 않은 강재(Steel)바퀴 한 종류를 사용하였으며, 반복주행시험을 통하여 바퀴재질에 따른 혼합물의 소성변형 저항성을 평가하였다. 또한 반복주행시험에서 얻은 침하깊이와 동적안정도를 Kim test의 변형강도와의 상관성 분석을 통하여 반복주행 시험용 최적 바퀴를 선정하는데 이용하였다. 고무두께가 15mm, 7.5mm, 0mm에 대한 상관성 분석결과 각각 0.7, 0.8. 0.9 이상이 나와 고무를 사용하지 않은 강재바퀴가 변형강도와의 상관성이 가장 높은 값을 보여주어 향후 반복주행시험시 강재바퀴의 사용이 소성변형을 예측하는데 가장 유리 할 것으로 판단된다.

• 전기학회논문지
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• 제62권4호
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• pp.577-583
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• 2013

We have analyzed influence of potential rise in negative bus, which caused by decrease of power feeding line insulation, upon protecting method of DC ground protection device which detecting potential rise between negative bus and ground in order to detect ground fault in the rubber wheel system. For this purpose, we proposed negative potential equation between negative bus and ground and calculated negative potential according to system condition changes by estimating power feeding line insulation changes in steel wheel system and rubber wheel system, and equalizing DC power feeding system when ground fault occurred. Also, in order to estimate negative potential of real system, we modeled the rubber wheel system, and simulated normal status, grounding fault occurrence and power feeding line insulation changes. In normal status, negative potential did not rise significantly regardless of vehicle operation. When ground fault occurred, negative potential rose up over 300V regardless of fault resistance. However, we also observed that negative potential rose when power feeding line insulation dropped down under $1M{\Omega}$. In conclusion, our result shows that in case of rubber wheel system unlike steel wheel system, relay will be prevented maloperation and insulation status observation can be ensured when ground over voltage relay will be set 200V ~ 300V.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제27회 춘계학술대회
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• pp.271-276
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• 1998

To apply the wear resistant steel plate for heavy duty vehicle, the wear characterisms of various kinds of commercial steel plates were invesigated by dry sand/rubber wheel tester which was tested under scratch abrasion mode. The wear tested pnaterials were boron steels which were manufactured by thereto machanical control process (TMCP) in order to achieve higher hardness. As the result of the test, wear resistance of steel plate increases with the hardness and carbon content. The wear loss of wear resistance steel plate (Hv440) is a half times than tinat of SWS490A (Hv160) steel plate in dry sand-rubber wheel test and the result in field test is similar to this dry sand/rubber wheel test result. Therefore, dry sand/rubber wheel tester can be used to predict the scratch abrasion life of the parts for heavy duty vehicle.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.349-355
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• 2003

Traffic congestion caused by cverpopulation has a major detrimental effect on bringing about social and economic problems ia city area. Therefore Un order to maintain and sustain smooth flow of railway system, we are willing to introduce Light Rail Transit System. Rubber wheel type and guideway far AGT have been concentrated on our study Especially, the prototype of LRT turnout system has been developed. Furthermore, the structural analysis for the guideway system has been completed to secure reliability for the LRT system. In the near future, the tumout system of rubber wheel and guideway shall be applied in Korea. We hope reliability fer the system shall be secured without any major difficulties. As a result, we expect to expedite the localization of rubber wheel type and guideway for AGT.

• 한국정밀공학회지
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• 제23권1호
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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.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.1196-1201
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• 1993

Test of Caterpillar Challenger 65 tractor which has rubber tracks, and articulated four wheel drive tractor with dual wheels and a mechanical front wheel drive tractor were conducted on an unplowed and plouwed wheat stubble field. The following parameters were analyzed : tractive efficiency (ηv), net tractive coefficient ($\phi$n), slip ($\sigma$) , drawbar pull(Fv), drawbar power (Pv) and forward velocity(v). The maximum net tractive coefficient was established at the tractive efficiency of 0.60 on the unplowed wheat stubble field : for the Challenger 65 tractor 0.855 ; 4WD 0.624 and MFWD 0.534 and on the plowed wheat stubble field with the tractive efficiency of 0.40 for the Challenger 65 tractor 0.82 : 4WD 0.57 and for tractor MFWD 0.48.

• 한국자동차공학회논문집
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• 제9권5호
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• pp.165-172
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• 2001

Wheel bearing units were almost exclusively used for car front wheel, where the two ball rows are directly side by side with integrated rubber seal. The seal is of important for wheel bearing units due to the adverse environmental conditions with mud and splash water. The seal of wheel bearing units was designed to have geometry with multi lips, which elastic lip contacts and deforms with bearing. The equation of reaction force for deformed lip as cantilever beam was previously used for seal lip design. But it's result was not useful because deflection of the beam differs from lip's. In this study, deformed shape of the lip was assumed to and order function which is more similar to lip deformation and made the equation for reaction force prediction. The Reaction forces from each other equations were compared with results by FEA to prove usefulness of new equation.

• 대한소아치과학회지
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• 제6권1호
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• pp.7-13
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• 1979

To evaluate the surface roughness of subgingival area of S. P. crown margins subjected to various polishing procedures, the study was performed by use of metallograph and surface roughness tester. The following results were obtained; 1) Abrasive stone wheel produced the roughest surface ($16.0{\mu}m$). 2) Final polish with rouge after polishing with rubber wheel, subsequent to abrasive stone wheel, produced the smoothest surface ($0.3{\mu}m$). 3) Both polish with rubber wheel after polshing with abrasive stone wheel, and polish with pumice (coarse$\rightarrow$medium$\rightarrow$fine) produced same surface roughness ($0.8{\mu}m$).

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.1197-1204
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• 2004

The metropolitan cities and operation companies of urban transit railway are driving to construct the LRT(light rail transit) system because of the advantage of construction cost and environmental serviceability. This study suggests the optimal design method of steel box girder considering dynamic characteristics of LRT with rubber wheel. The behavior and design constraints are formulated based on the structural design criteria for LRT. Genetic algorithm is applied to the minimum weight design of structural system. A typical example is solved to illustrate the applicability of the proposed minimization algorithm. From the results of application example, the optimum design of steel box girder is successfully accomplished. Therefore, this system can act as a consultant to assist novice designers in the design of steel box girder for LRT with rubber wheel.

• Tribology and Lubricants
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• 제35권5호
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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.