• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.11
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• pp.1064-1070
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• 2012

This paper analyzes the pitting's cause of elevator's worm gear type traction machine. To find a cause of pitting problem, we analyzed vibration, a proper design allowance and lubrication. We brought a conclusion that the cause of pitting is not a simple vibration problem, such as misalignment of worm reducer and rail, but mostly related to a designed allowance. In this case, the allowance is tight. In general, the allowance of traction machine and lubrication is varied by manufacturers. When the allowance is tight, a proper lubrication can diminish the pitting problem.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1529-1534
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• 2008

Recently, mixers are being widely used in the display and semiconductor company in order to mix the chemical materials. The mixer normally consists of shaft, hub, reduction gear, and driving motor. It is one of the key design factors to evaluate the dynamic characteristics caused by the rotation. In this study, the dynamic characteristics of the high speed mixer, such as vibration, noise and thermal radiation, are verified by the experiment. Through the experiment, it is shown that the structural unbalance mass of high speed mixer is the important source of the severe vibrations and maximum temperature is mixer bowl.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.4
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• pp.129-135
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• 1996

The area of gear vibration and noise, has recently been the focus of many studies. The proper kinematic and geometric design of gears, the mathematical modeling of gear system are essential for a good design. This work present a gear disign for reducing noise, and practical approaches used for machinery noise reduction slong with the summary of methods available for predicting gear noise in terms of the transmis- sion error, and show a comparative study with other methods. A new tooth profile modification is proposed for reducing vibration and noise of involute gears. The method is based on the use of cubic spline curves. The tooth profile is constrained to assume an involute shape during the loaded operation. Thus the new gear profile assures conjugate motion at all points along the line of action. The new profile is found to result in a more uniform static transmission error compared to not only standard involute profile but also modificated profile therby contributing to the improvement of vibration and noise characteristics of the gear.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.4
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• pp.762-767
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• 1998

The main torsional vibration source of the powertrain is the fluctuation of engine torque. The gear rattle is impact generating in the backlash of the free gear due to this torsional vibration. Optimization of the clutch torsional characteristic is one of the effective method to reduce the idle gear rattle. Many researches have been reported on this problem but only few of them give sufficient consideration to the detailed clutch modeling and the experiment. This paper pays attention to the optimization of clutch design parameters and the experiment to reduce the idle gear rattle vibration and noise.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.10a
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• pp.269-275
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• 2001

정밀가공기계 및 소음발생원의 방진재료로서 사용될 수 있는 재료는 우선 내부 및 외부진동의 흡수성과 감쇠성이 뛰어나야 하고, 시간 및 온도변화에 따라 형상 및 치수 정밀도가 안정되어야 하며, 불규칙한 외력과 운동전달기구의 변동 하중 하에서도 높은 정적, 동적 강성을 유지해야 한다. 본 연구에서 개발한 재료인 Ferrite-Resin 복합재료는 Resin-Concrete에 미세한 산화철을 filler 재료로 사용함으로써 주철 및 강의 구조재료가 갖는 강성과 비중의 값에 접근시킬 수이었다. 일반적으로 불포화 폴리에스테르 수지나 에폭시계 수지는 glass 전위점의 근처에서 진동에너지의 흡수가 큰 영역이 존재하며 이는 10 .mu.m 이내의 미세한 filler재료가 포함되었을 경우에도 그 종류에 관계없이 큰 변화가 없는 성질이다. 시험편을 통한 재료실험을 통하여 개발된 복합재료를 모델 구조물에 적용시킴으로서 그 적용성을 검토하였다. 앞으로의 수지와 Ferrite 함유량 및 제조 공정이 적절히 모색되면, 이 방진재료가 정밀기계의 구조재료로서 뿐만 아니라 냉동기, 소형선박의 기관실, 가전제품 및 기어박스 등의 케이싱 재료로 사용되는 방진재료로서 그 응용이 확대될 수 있을 것으로 본다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.12
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• pp.3246-3252
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• 1994

The vibration of meshing gear system is originated form teeth deformation, teeth contact ratio, profile error, etc. The gear vibration is classified as whine vibration during meshing and as rattle vibration during idling. In this study, the whine vibration is investigated under the assumption of piecewise linearity of elastic stiffness due to the variation of meshing. Numerical, theoretical and experimental investigations show the existence of the superharmonic components of the second and the third order. consistently It can be concluded that the superharmonic components in whine vibration of meshing gear is originated from the stiffness variation. It also shows that the higher order harmonics are reduced on the increase of motor speed.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.579-583
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• 2001

Cause of noise/vibration for the sheet feeding apparatus of digital MFP is investigated by analyzing the measured sound pressure and the strategy for reducing the noise level is suggested. Factors related to the noise/vibration are found by loading test and the measurement of the noise by assembling the components. By checking the center distance between gears and the boss height, precision of assembly is identified as a main factor of noise. From the result of analysis, it can be concluded that the noise level of sheet feeding apparatus can be reduced by maintaining the distance between gears and the precision of assembly adequately.

• Journal of the Korean Society of Safety
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• v.13 no.1
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• pp.34-39
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• 1998

This paper describes a evaluation method of sound power radiated from the vibrating faces of a single stage gear box using sound radiation. The vibration caused from meshing gears is transmitted to the gear box faces through shafts and bearings. A Boundary Element Method (BEM) is developed to calculate the sound power radiated from the faces with their velocity response which is based on the Building Block Approach (BBA). Radiation efficiency as well as the sound intensity on the surface of the gear box is also calculated. Sound power of the gear box is larger in the case that bearings have offset to the wall of the gear box than that bearings are on the center of the gear box. The sound power increases with the augmentation of the offset.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.11
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• pp.73-82
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• 2008

A dynamic model of reducer for generating facility of electric pourer having bevel gear pair and planetary gear train is developed by lumped method. The model accounts for the shaft and bearing flexibilities, gyroscopic effects and the force couplings among the transverse and torsion motions due to gearing. Vibration/noise analysis as well as strength of bevel gear pair and planetary gear train are considered. Exciting forces of high reducer for generating facility of electric power areconsidered as the mass unbalance of the rotors, misalignment and a function of gear transmission error. A Campbell diagram, in which the excitation sources caused by the mass unbalance of the rotors, misalignment and the transmitted errors of the gearing are considered, shows that, at the operating speed, there are not critical speed.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.4
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• pp.107-117
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• 1996

The shift feeling, a driver experiences during gear shifting, is a major factor in manual transmission quality. Recently, the shift feeling has becoming more severe every year in proportion to the higher torque and revolution speed of today's automotive engine. In this paper, first, the diagram of a relation between cone angle, sleeve chamfer angle, and friction coefficient of ring is investigated for easy design of Synchromesh system. And then, methodology to solve the shift problems such as clashing noise and rough shift, ect. by analyzing the synchronization procedure in sequence and by investigating the shift waveform if presented.