• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.7 s.100
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• pp.865-870
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• 2005

Torque fluctuation of the engine and angular velocity variation of propeller shaft is the main excitation source for torsional vibration in the vehicle driveline. Experimental model for engine system is constructed with 4 cylinder 4 cycle diesel engine including Motor-Propeller Shaft-Axle-Wheel system. The angular velocity is measured by magnetic pickup and FV converter at the engine flywheel and propeller shaft. This paper presents the theoretical mechanism of these excitation sources and it is identified by the experimental methods.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.10a
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• pp.316-321
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• 1997

The purpose of this study is to reduce the vibration noise of differential gear by reducing torque fluctuation of drive pinion shaft which causes vibration noise of differential gear in rear wheel drive vehicles. For this we developed multi-degree of freedom analysis model in which mass moment of inertia and torsional spring combined, the validity of the simulation model was checked by the field test and we examined the influence of torsional vibration of driveline elements by performing forced vibration analysis of engine excitation torque. We studied the methods for reducing torsional vibration of driveline according to the design factor of propeller shaft and examined the effects reducing vibration differential gear by applying flexible coupling.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.6
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• pp.45-54
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• 2019

In this study, we analyze the rattle noise of a power takeoff (PTO) driveline and develop a PTO driveline resonance model. We measured the rattle noise of the PTO driveline on the output shaft and, by analyzing the rattle noise in the time domain, we determine that the engine expansion stroke period matches the sound pressure of rattle noise. This finding helped us demonstrate that the rattle noise is caused by the collision between the PTO driving gear and the gear driven by the engine expansion stroke; the torsional vibration caused by this collision is affected by the angular velocity fluctuation of the PTO drive shaft. By measuring the angular velocity of the PTO drive shaft, we confirm that the angular velocity fluctuation of the engine flywheel tends to excessively amplify the PTO drive shaft angular velocity fluctuation. We conclude that the resonance, which occurs when the operating frequency of the engine is close to the natural frequency of the tractor power transmission system, causes the excessive angular velocity fluctuation of the PTO drive shaft. We performed a modal analysis of the PTO driveline resonance and, using the characteristic equation, we show that the resonance occurs when the engine rotation speed is close to 850 rpm, which matches the natural frequency of the PTO driveline.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.1
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• pp.169-176
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• 1998

This paper presents the vibration characteristics of a motorcycle body frame. In order to study the excitation mechanism. for example, of handle vibration, discrete models and finite element model are developed for the calculation of natural frequencies and mode shapes of the driveline and body. which can lead to the resonances. Experiments are also conducted to compare with the analytical results From the various kinds of vibration reduction methods, the technical realizable one is presented to reduce the handle vibration responses at the start of driving.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.3
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• pp.209-217
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• 2002

This gaper discusses a multidisciplinary design optimization of the engine mounting system to improve the ride quality of a vehicle and to remove the possibility of the resonance between the powertrain system and vehicle systems. The driveline model attempts to support engine mount development by providing sufficient detail for design modification assessment in a modeling environment. Design variables used in this study are the locations, the angles and the stiffness of an engine mount system. The goal of the optimization is both decoupling the roll mode ova powertrain and minimizing the vibration transmitted to the vehicle including the powertrain, simultaneously. By applying forced vibration analysis for vehicle systems and mode decouple analysis for the engine mount system, it is shown that improved optimization result is obtained.

• Journal of the Korean Society for Precision Engineering
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• v.8 no.4
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• pp.137-145
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• 1991

A universal joint is a connecting device of two hinges which can transmit torque from one shaft to another at fixed or at varying angles of intersection. It has been used properly not only as rotational but also as intermittent motion. For the particular kinematics condition of a universal joint, torsional and bending vibrations are produced excessively in an elastic driveline. In this paper only the torsional vibration behavior of a driveline with universal joints is analyzed numerically with the discrete model and a design method of the dynamic vibration damper is proposed, in order to reduce torsional vibrations especially in resonance region as a result of parametric variation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.11
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• pp.1957-1964
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• 1997

Torsional vibration is to vibrate strongly when the ignition pulses of the engine is excited with natural frequency of driveline. Torsional vibration like this can cause various noises as rattle and booming. For this study multi-degree of freedom analysis model of torsional vibration, which is combined with mass moment of inertia and torsional spring, was developed toward two wheel drive, four wheel drive and torsional vibration characteristics were compared and analyzed through the natural frequences, mode shapes and frequency response characteristics which was acquired by the simulation of it. The pertinence of that model was proved by the field test and the outcome of the simulations coincided with feeling test. Therefore, four wheel drive simulation model is considered to be useful thing for reducing torsional vibration of driveline and developing full-time four wheel drive vehicles.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.3
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• pp.1-7
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• 2007

Torque fluctuation of an engine and angular velocity variation of a propeller shaft are the main excitation sources in a vehicle driveline. This paper presents the mechanism of these excitation sources. An equivalent model of the engine system and propeller shaft system is constructed to simulate the excitation phenomena. The analytical model contains the geometrical and dynamic mechanism. Combustion pressure of the cylinder is measured from dynamometer. The computer simulation is carried out by commercial program package. Results of the simulations show the characteristics of the torsional excitation source of the driveline.

• 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 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.