• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.4
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• pp.245-250
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• 2015

To verify the possibility of generating rattling noise from a motor on caliper brake system, a test was conducted using a caliper excited with vibrations similar to that in a vehicle running on actual roads; this test was conducted using a quiet shaker installed in an anechoic room. After several hours of external excitation, the test assembly was loosened, and the frequency of rattling noise generation increased. A microphone was used to record the generated noise. The measured signals were analyzed by conventional spectrum analysis. Since the noise is generated as an impact response, the advantages of employing Prony analysis was discussed, and the results were compared to those obtained using conventional fast Fourier transforms. The accuracy of Prony analysis was through endurance tests on different brake systems.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1994.04a
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• pp.100-105
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• 1994

본 연구에서는 변속기 중립상태에서 클러치 설계 인자인 비틀림 스프링과 건마찰에 의해서 클러치에 나타나는 히스테리시스, 그리고 클러치 디스크의 정적처짐을 발생시키는 드래그토크(drag torque)가 클러치의 동적인 거동과 기어래틀에 미치는 영향을 분석하고자 한다.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.3
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• pp.88-96
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• 1998

The rattle noise is the most significant in many kinds of manual gearbox nioses, which is generated at the idle stage of the engine operation. The main torsional vibrat- ion source of the driveline is the fluctuation of the engine torque. The gear rattle is impacts generating in the backlash of the free gear due to this torsional vibration. Many researchers reported the clutch torsional characteristic optimization method to reduce the idle gear rattle but only few of them give sufficient consideration to the system parameters like gear backlash, drag torque, system inertia, inertia distribution, engine torque fluctuation, idle engine rotation speed, and accessory load. In this paper, influence rate of system parameters on the gear rattle is presented and counterplans like backlash reduction, drag torque increase, inertia addition, inertia distribution modification and engine torque characteristic control are suggested.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.562-566
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• 1997

The main torsional vibration source of the driveline is the fluctuation of the engine torque. The gear rattle is impacts generating in the backlash of the free gear due to this torsional vibration Optimization of the clutch torsional characteristic is one of the effective methods to reduce the idle gear rattle. Many researches have been reported on this problem but only few of them give sufficient consideration to the full clutch design parameters(stiffness, hysteresis torque, preload, first stage length) and drag torque This paper pays attention to the gear impact mechanism, clutch design parameters and drag torque to reduce the idle gear rattle with computer simulation.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.3
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• pp.29-36
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• 1998

In recent year, as the demand about low vibration and noise vehicle is increased constantly. automobile companies try to a lot of things to achieve this demand. Gear rattle vibration become an emergency problem to be cured at idling. There are two kinds method to reduce idle gear rattle vibration One is optimization of clutch damper design parameters(stiffness, hysteresis torque, preload, length of lst stage) the other is system parameters modification(inertia, drag torque, backlash, etc) But these methods are impossible to estimate influence rate of each gearpair on the idle gear rattle vibration. In this study, 14degrees of freedom nonlinear model is developed to analyze influnce rate of each gearpair on the idle gear rattle vibration and the counterplan to reduce the gear noise is suggeted through the shift system modification.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.2
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• pp.30-41
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• 1995

Gear rattle is a source of vibration and noise in automotive gearbox casing and generally occurs at or near system resonant frequencies. The neutral gear rattle of the gearbox. is affected by the stiffness and hysteresis torque in the clutch disk and drag torque determining balancing point of the clutch disk operating range. The experiment is carried out in the pre-damper type clutch and a manual transmission of a automobile equipped for inline four-sylinder four-cycle 1.5L MPI engine and the computer simulation is executed by 5th order Runge-Kutta method. The results of the simulation analysis and experimental studies show the dynamic behavior of clutch and a phenomenon of the neutral gear rattle with respect to drag torque and torsional characteristics of the clutch.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.5
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• pp.679-683
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• 2013

BSR noise emerges in a vehicle as a result of road vibrations, engine vibrations, and speaker vibrations. BSR noise occurs with an irregular impact or stick slip friction phenomenon as the influence of the resonance mode when the vibration input load is transferred along poor joint and contacting pairs of the system. A sub-structure method of finite element analysis is required to detect impacts and slip in the full vehicle model. This study presents a method for sub-structure modeling and a rattle and squeak detection methodology that considers the characteristics of road vibration inputs.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.658-659
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• 2014

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.67-68
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• 2010

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.650-651
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• 2011