• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.313-317
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• 2001

Magneto-Rheological fluid (MR fluid) is known as a class of functional fluid with controllable apparent viscosity of the fluid by the applied magnetic field strength. Extensive researches with the functional fluids have been done on applications of the fluid to mechanical components such as suspension, absorber, engine mount, clutch, break, valve, etc. In this study, a new torsional damper using MR fluid is proposed, and the response property of the damper was theoretically investigated. The present damper is quit effective for reducing the driveline vibration in a wide range of the engine speed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.6
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• pp.377-383
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• 2015

Torsion mode or bending mode of drive-line for rear-wheel drive vehicle exists in low frequency band. If resonance exists there between natural mode of driveline and powertrain excitation force, drive-line will manifest excessive vibration response. Also, the vibration response can be transmitted to vehicle body and can induce booming noise. A vehicle in this study exhibits a booming noise problem under specific transmission gear condition. To draw performance improvement plan, finite element analysis technique was used. Modification was evaluated qualitatively and priorities were derived. Finally, effectiveness of best modification was verified through test and full vehicle FE analysis.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.2
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• pp.51-61
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• 1995

A coast down test mothod has been used to determine the resistance forces on running vehicle due to the aerodynamic drag, rolling resistance and driveline resistance. Most of the tests, however, are based on the Velocity-Time measurements, which require a sophisticated velocity measuring device and contain much error by nature. In the present study a coast down test method based on Distance-Time measurements is introduced, which contains the original idea of Russian scientist Prof. Petrushov along with the suggestions for improvement of the accuracy.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.3
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• pp.132-140
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• 1996

This paper developes a torsional vibration model of heavy duty truck drive line for simulation of a driving rattle, which causes very annoying noise to driver at the full load driving condition. Test results show a peak in the fit plots at the frequency of the 2nd harmonics of propeller shaft revolution. A 10 d.o.f. lumped parameter nonlinear torsional vibration model is constructed and engine torque variation is calculated from P- .theta. diagram. Time responses are simulated and compared with the test results, which show fairly good agreement. The effects of paramenter change are investigated, and the optimum configuration is proposed.

• Journal of the Korean Society of Safety
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• v.27 no.4
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• pp.121-127
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• 2012

Vehicle Inspection System is to examine the condition of vehicle regularly at the national level to protect lives and properties of the people from traffic accidents due to vehicle's fault. However, the vehicle inspection method, criteria, period and effectiveness have become a controversial issue, because of examining safety management of vehicle by drivers regardless of regular vehicle inspection. Therefore, the aim of this study is to investigate vehicle inspection timeliness and risk level of inspection items through basic statistical survey and portfolio analysis. The results of the research through practical analysis are: (1) The inspection failure rates between 3 and 6 model year tend to increase. (2) The failure of inspection items for safety highly impacts on traffic accident rate in terms of accident risks. (3) According to the result of portfolio analysis, faulty items located 1st quadrant are riding device, driveline system, controlling device, steering actuator, and fuel system.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.7
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• pp.221-228
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• 1999

A full-time four wheel drive vehicle is driven literally full time by the front and the rear wheels. Front and rear drive shafts are rotated rapidly in the extremely torsional state, which can cause various vibration and noise problems. The purpose of this study is to reduce the vibration and the noise of the full -time four wheel drive vehicle. In this paper, both the causes and the methods for reduction of torsional vibration are suggested. For this study, the characteristics of the torsional vibration are analyzed by free and forced torsional vibration simulation. And this paper described the influence upon the torsional vibration with emphasis shafting system. The validity of simulation models is checked by the field test. The forced vibration simulation with the variations of shaft design factors are performed by the checked models. According to the simulation , the resonance region shifts and the torque fluctuation varies in the system,. Finally, the methods and the effects for the torsional vibration reduction in driveline are proposed.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.9
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• pp.915-921
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• 2013

Most of large scale solar panel handling robots adopt the timing-belt drive system for its driveline because of the simplicity and the easiness of implementation. The vibration caused by the flexure of the timing belt would increase as the size and the weight of the panel that the robot handles increase and the vibration would deteriorate the precision and/or productivity of the whole robot system. For the development of a proper control system and for the improvement of the design of the robot it is important to estimate the oscillatory response of the robot system including the flexible drive system properly. In this paper a flexible multi-body dynamics model of a large-scale solar-panel-handling robot with the flexible timing-belt drive system is developed using a generic multi-body dynamics analysis program, RecurDyn.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.8
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• pp.8-17
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• 2019

In this study, a model reduction technique was used to develop a precise noise and vibration prediction model for the individual components of a driveline system. The dynamic reduced-order model generated by the Craig-Bampton method was applied to perform dynamic analysis of an electric agricultural power cart. The natural frequency and acceleration response results were analyzed according to the different number of dominant sub-structural modes contained in the reduced-order models. Through the analysis results, it was confirmed that a sufficient number of dominant sub-structures to satisfy the operating conditions should be selected to construct an optimal reduced-order model.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.9
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• pp.20-27
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• 2021

The effective surface of lens was studied for injection molding process and to enable mass production of f-theta lens, which is the primary component of laser printers and laser scanning systems. Injection molding is an optimal method if f-theta lens is frequently used for the mass production of plastic lenses as an aspherical lens that requires ultra-precision. A uniform injection molding system should be maintained to produce high quality lenses. Additionally, to maintain these injection molding systems, various factors such as pressure, speed, temperature, mold and cooling should be considered. However, a lens with the optical characteristics of an f-theta lens can be obtained. The effects of melting and cooling of plastic resin on the effective surface of f-theta lenses and the numerous factors that affect the injection molding process were studied.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.11
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• pp.115-120
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• 2021

In this study, cigarettes, which are an essential element in the production of tobacco, are generally not cylindrical. The main materials used for cigarettes are generally hemp and pulp. For the production of cylindrical cigarettes, the cigarettes or cylinders are mounted via gluing. This adhesive is a vinyl acetate emulsion, a high-temperature melt adhesive, and is adhered in a cylindrical shape immediately after being linearly applied to the inner surface of the paper roll or a local part. These adhesives are greatly affected by the atmospheric temperature of the manufacturing space in summer and winter. In the summer, even if the adhesive is temporarily adhered, the coagulation time of the adhesive is long, and problems such as deterioration of the adhesive state occur. in the winter, there is a problem that the temperature of the manufacturing space is low and the adhesive force of the adhesive is poor, resulting in defective adhesive products. In order to solve these problems, another heat transfer device is utilized to cure the remaining adhesive to ensure higher adhesiveness.