• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.2
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• pp.59-64
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• 2003

Continuously Variable Transmission (CVT) consists of a driving pulley and a driven pulley joined by rubber V-belt. Each pulley consists of a fixed flange and a movable flange. The main advantages of the U with V-belt, which has been Popular in Asia, are a simple mechanism less maintenance and low cost. One of the important factors which have an influence on the performance of the CVT is change of axial distance. Base on an experiment the effects of transfer torque and speed ratio of both driving pulley and driven pulley during the alteration of axial distance were studied.

• Design & Manufacturing
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• v.14 no.1
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• pp.30-35
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• 2020

Plastic pulleys used for the purpose of power transmission have to very high roundness characteristics. The roundness of plastic pulleys is influenced by many factors. In this study, the effect of molding conditions on the roundness of pulleys was analyzed using a numerical analysis program. To improve the roundness, molding conditions that minimize the amount of deformation of the pulley were studied through an experimental design method. Among the experimental design methods, the Taguchi method was used, and the main molding conditions affecting the deformation of the pulley were the resin temperature and the holding pressure. It was found that the amount of deformation is reduced by about 2.86% when molding with the optimum molding conditions compared to when the optimum molding conditions are not applied.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.637-638
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• 2006

V-belt pulleys play a key role in driving cooling pump, oil pump, air-conditioner and so on by using an engine power. Precision deep drawing is one of the main processes for manufacturing the pulleys. Operation variables of the deep drawing equipment, called the setup parameter, must be re-determined whenever the specifications of pulley to be produced are changed. The defect rates during a setup of equipment and the working hours needed for the setup are almost dependent on workers' know-how. This study designs the program for easily determining setup conditions in pulley manufacturing process.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.2
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• pp.129-135
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• 2011

Dry CVT(Continuously variable transmission) consists of a driving pulley and a driven pulley joined by rubber V-belt. Each pulley consists of a fixed flange and a movable flange. The movable flange of the driving pulley has the centrifugal roller and a ramp plate in the flange. The movable flange moves toward a fixed flange under the actuation of a centrifugal roller, as the driving pulley speed increases. The main advantages of the Dry CVT with V-belt, which has been popular in Asia, are a simple mechanism, less maintenance and low cost. The important claim which have an influence on the performance of the Dry CVT is the wear of the centrifugal roller. In this study ball type is proposed instead of roller type of movable flange to resolve claim. Also experiments are carried out for new model to evaluate performances.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.201-202
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• 2006

• International journal of advanced smart convergence
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• v.12 no.4
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• pp.451-457
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• 2023

Global warming is causing abnormal climates such as floods, droughts, and typhoons all over the world. According to some scientists, carbon dioxide emitted from automobiles is the main cause of global warming. To cope with this, each country is making efforts to replace the existing fossil fuel-powered engine-driven cars with electric vehicles. In order to commercialize small electric vehicles in Korea, it is necessary to solve many problems such as improvement of hill climbing capacity and improvement of power performance. In this study, we propose a proprietary model for a continuously variable transmission(CVT) of a small electric vehicle that can be operated on hills, in which a spring is mounted on a driving pulley and a driven pulley. A prototype of the CVT model using a spring was manufactured and attached to a small electric vehicle body.

• Journal of Power System Engineering
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• v.10 no.3
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• pp.73-80
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• 2006

The main advantages of the Dry CVT with V-belt, which has been popular in Asia, are a simple mechanism, less maintenance and low cost. The important factors which have an influence on the performance of the CVT are the weight of the centrifugal roller, the change of axial distance and spring force. Based on an experiment, the effects of load torque, speed ratio, and revolution of both the driving pulley and the driven pulley during the alteration of the axial distance, roller weight and spring constant were studied.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.5
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• pp.479-487
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• 2023

Recently, the destructive power of typhoons is continuously increasing owing to global warming. In a situation where the installation of floating wind turbines is increasing worldwide, concerns about the huge loss and collapse of floating offshore wind turbines owing to strong typhoons are deepening. A new type of disconnectable mooring system must be developed for the safe operation of floating offshore wind turbines. A new submersible mooring pulley considered in this study is devised to more easily attach or detach the floating of shore wind turbine with mooring lines compared with other disconnectable mooring apparatuses. To investigate the structural safety of the initial design of submersible mooring pulley that can be applied to an 8MW-class floating type offshore wind turbine, scale-down structural models were developed using a 3-D printer and structural tests were performed on the models. For the structural tests of the scale-down models, tensile specimens of acrylonitrile butadiene styrene material that was used in the 3-D printing were prepared, and the material properties were evaluated by conducting the tensile tests. The finite element analysis (FEA) of submersible mooring pulley was performed by applying the material properties obtained from the tensile tests and the same load and boundary conditions as in the scale-down model structural tests. Through the FEA, the structural weak parts on the submersible mooring pulley were reviewed. The structural model tests were conducted considering the main load conditions of submersible mooring pulley, and the FEA and test results were compared for the locations that exceeded the maximum tensile stress of the material. The results of the FEA and structural model tests indicated that the connection structure of the body and the wheel was weak in operating conditions and that of the body and the chain stopper was weak in mooring conditions. The results of this study enabled to experimentally verify the structural safety of the initial design of submersible mooring pulley. The study results can be usefully used to improve the structural strength of submersible mooring pulley in a detailed design stage.

• Journal of the Korean Society for Railway
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• v.12 no.5
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• pp.663-669
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• 2009

In the electrical railway, the increase of tensions in an overhead contact lines is essential to speed-up of train, because current collection quality largely depends on the ratio of a wave propagation speed to a train speed. For Kyungbu high-speed line, a pulley-type tensioning device is required to have a tension variation of maximum 3%. Therefore we developed a pulley-type tensioning device in order to meet tension variation requirement of the high-speed tensioning device. To verify the performance of the developed device, a performance test, overload test and failure test were carried out according to the factory test procedure of the Kyung-Bu High-speed line. Furthermore, we also performed reliability performance through not only a fatigue test in a factory, but also on-line verification test in Chungbuk line for over 1 year. These tests verified that the tensioning device had applicability to a main line.

• Steel and Composite Structures
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• v.21 no.4
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• pp.863-882
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• 2016

This study aims to introduce a new bracing system by which even super-wide frames with large openings can be braced. The proposed system, hereafter called Cable-Pulley Brace (CPB), is a tension-only bracing system with a rectilinear configuration. In CPB, a wire rope passes through a rectilinear path around the opening(s) and connects the lower corner of the frame to its opposite upper one. CPB is a secondary load resisting system with a nonlinear-elastic hysteretic behavior due to its initial pre-tension load. As a result, the required energy dissipation would be provided by the MRF itself, and the main intention of using CPB is to contribute to the initial and post-yield stiffness of the whole system. Using a stiffness calibration technique, optimum placement of the CPBs is discussed to yield a uniform displacement demand along the height of the structure. A displacement-based design procedure is proposed by which the MRF with CPB can be designed to achieve a uniform distribution of inter-story drifts with predefined values. Obtained results indicated that CPB leads to significant reductions in maximum and residual deformations of the MRF at the expense of minor increase in the maximum base shear and developed axial force demands in the columns. In the case of a typical 5-story residential building, compared to SMRF system, CPB system reduces maximum amounts of inter-story and residual drifts by 35% and 70%, respectively. Moreover, openings of the frame are not interrupted by the CPB. This is the most appealing feature of the proposed bracing system from architectural point of view.