• 소음진동
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• 제10권1호
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• pp.74-81
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• 2000

The vibrational model of a helical gear pair is developed with considering the elastic deformation of the active teeth and the body to be a rigid. The main source of vibration in geared system which has been known to be the gear transmission error is mathematically formulated and used for the analysis of vibrational characteristics of geared system. As an example, a simple geared system containing a helical gearing is considered. The critical speeds are found by the campbell diagram and compared with the experimental results.

• 대한기계학회논문집A
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• 제34권2호
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• pp.237-243
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• 2010

본 논문은 자동차 변속기의 헬리컬기어 검사 장치에 대한 것이다. 기어 프로파일 전용 검사설비는 시간이 많이 소요되므로 생산라인용으로 적합하지 못하다. 본 논문에서 사용된 마스트기어를 이용하여 생산된 기어와 비교하여 방법은 보다 경제적이며 효율적이다. 본 논문에 사용된 3가지 기어검사 파라미터는 nick, 흔들림(run-out) 및 PCD (pitch circle diameter) 등이다. 기어검사장치의 측정정밀도에 영향을 미치는 요소들에 대해서도 또한 언급되었다. 이 장치는 현재 국내에서 전량 수입되는 기어 생산라인용 설비에 실제적으로 사용될 것이다.

• Journal of Biosystems Engineering
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• 제19권4호
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• pp.291-300
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• 1994

It is desired to operate tractor engines at or near maximum torque much of the time in field operation to increase fuel efficiency. To do this it is necessary to reduce engine speed and to shift gears to higher ratios as frequently as possible. Because of load variations in most drawbar work and inconvenience in gear shift, however, gear-type transmission are usually set in one ratio at unnecessarily high engine speeds, and engine-torque variations are used to compensate for changes in drawbar load. As a result, the most of time the tractor is not operated efficiently in terms of fuel consumption and work output. The objective of this study was to develop an automatic control system which is able to operate a tractor equipped with gear transmission under the optimal condition in terms of fuel efficiency with automatic governor setting and gear shift. An indoor experimental test set which can be used to simulate tractor operation, control engine speed and transmission ratio was developed in the previous paper. In this paper, the performance of the optimal operation system is reported. Through a series of tests, it was found that the automatic control system for optimal operation of tractors with gear transmission had a satisfactory performance.

• 한국자동차공학회논문집
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• 제6권6호
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• pp.243-251
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• 1998

A method of establishing the tooth modification for gear transmission of vehicles to reduce gear whine noise, caused by tooth impact phenomenon of mating gear, is introduced. The major causes of tooth impact are due to the deflections of gear teeth and shafts of transmission with the loaded condition including various kinds of manufacturing errors. The theoretical shape of tooth surface to avoid tooth impact is derived by the amount of elastic deformation of gear teeth and shaft and overall manufacturing error of machine tool. The surface function is converted with respect to the conventional commercial data usually communicated to the gear inspection system. The proposed method is applied to the gearbox of four wheel drive vehicle and shows the gear whine noise decreased to the 8 dB in the sound level.

• 산업공학
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• 제14권2호
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• pp.134-139
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• 2001

This paper describes an automatic design system for the parts that compose the power transmission. Power transmission is composed of shaft, gear, clutch, brake and housing. To design power transmission, there are many recurrent calculations and drawings needed with conventional design process. In this paper, we propose three dimensional automatic design system that reduce recurrent calculations and drawings. Developed system consists of two modules; 1) Design expert system module to assist determining design parameters of clutch, brake and gear. 2) Parametric modeling module to make three dimensional solid model automatically. The proposed system has been tested in the fields and found to be a useful system.

• 한국안전학회지
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• 제10권4호
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• pp.13-21
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• 1995

On mini-bus with diesel engine, at idle rpm for taking measurement to reduce gear rattle noise, was tested by the three clutch disc samples by turns, then measured the fluctuation of revolution of engine & transmission and parallel vibration of differential gear & transmission. By analyzing the measured data, the gear rattle noise, the matching design and tuning technic of transmission are comprehended and established. Conclusions of this test are as follows ; (1) Fluctuation of revolution on transmission is greatly affected by torsion of clutch disc according to fluctuation of engine revolution transmit to transmission through clutch system. Especially, gear rattle noise can be reduced by minimaizing the fluctuation of the revolution of transmission using pre-damper type clutch disc. (2) The reason of gear rattle noise is higher in summer than winter and driving longer period than initial driving is due to affection by drag torque changing. So, it is necessary for manufacturer to choose proper oil to transmission. (3) It can be occurred jumping and crash noise by applying the pre-damper type clutch disc for reducing the gear rattle noise. So, it is necessary to do test with actual vehicle according to test procedure.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.602-603
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• 2014

A gearbox can be regarded as a self-exciting dynamic system, which has a vibration source. Transmission error (TE) is considered to be an main excitation source for gear noise and vibration. The TE excitation is transmitted through the gears, shafts, bearings, and housings. Thus, an experimental approach to each mechanical parts is useful in order to understand and evaluate the dynamic behaviour of a gearbox. This study is focused on the transmission and vibration characteristics of a helical gear system in development stage. In addition, by considering the tolerance factors and resonance characteristics, the vibration response of actual dynamic system is analysed.

• 한국정밀공학회지
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• 제13권10호
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• pp.36-45
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• 1996

The precise estimation of the reliability and life of the Ravigneaux planetary gear train used in an automatic transmission is necessary in order to enable accurate material and geometric properties to reliability distrobution and the number of load cycles at failure. These are critical for the proba- bilistic design of complex planetary gear system as Ravigneaux type particularly during various gear ratios. The Ravigneaux planetary gear train has five gears, such as a forward and a reverse sun gear, a short and a long pinion, and an annulus gear. In this paper, the Ravigneaux gear system is analyzed to figure out the reliablity distribution. i.e. the probability of survival in the system without its overhaul. First, the reliablity method based on the Weibull distribution is used in conjuction with the Palmgren's model to predict both the individual reliabilities of its components and the nimber of load cycles when the system failed. Then using the presented method, the life of the Ravigneaux gear system can be determined. Alwo the different design parameters such as tooth face width, material property, and Weibull exponent are applied and reached to optimal ones. Thus, the precise evaluation of the reliability and life of the Ravigneaux planetary gear train used in an automatic transmission can be effectively carried out.

• 한국기계가공학회지
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• 제20권5호
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• pp.8-16
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• 2021

This study develops a shaft analysis model for the optimization of the power transmission system. The finite element method was used for the shaft analysis model. The shaft and gear were assumed Timoshenko beams. Strength was evaluated according to DIN 743, and gear misalignment was calculated through ISO 6336 and the coordinate system rotation. The analysis software for a power transmission system was developed using Visual Studio 2019. The analysis results of the developed program were compared with those of commercial software (MASTA, KISSsoft, and Romax). We confirmed that the force, deformation, and safety factors at each node were the same as those of the commercial software. The absolute value of the gear misalignment of the developed program and commercial software was different. However, the gear misalignment tended to increase with increasing the displacement in the tooth width direction.

• Journal of Mechanical Science and Technology
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• 제20권7호
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• pp.941-949
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• 2006

Nonlinear behavior analysis was used to verify whether a one-way clutch is effective for reducing the torsional vibration of a paired spur gear system under periodic excitation. The dynamic responses were studied over a wide frequency range by speed sweeping to check the nonlinear behavior using numerical integration. The gear system with a one-way clutch showed typical nonlinear behavior. The oscillating component of the dynamic transmission error was reduced over the entire frequency range compared to a system without a one-way clutch. The one-way clutch also eliminated unsteady continuous jump phenomena over multiple solution bands, and prevented double-side contact, even with very small backlash. Installing a one-way clutch on both sides of the gear system was more effective at mitigating the negative effects of external periodic excitation and various parameter changes than a conventional gear system without a one-way clutch.