• 한국생산제조학회지
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• 제20권6호
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• pp.830-836
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• 2011

Most of pitch/yaw reducers consist of several planetary geartrains. Planetary geartrains make gearboxes to be small and light, low noise and good efficiency. Most important thing in the planetary geartrain is load distribution on the gear tooth flank. In this study, the effect of output shaft bearings on the load distribution of gear tooth flank has been investigated. The commercial software was employed to compare the load distribution of two models depending on the bearing type. The spherical roller bearing(SRB) and the cylindrical roller bearing(CRB) were used as output shaft bearings in the $1^{st}$ model, and two taper roller bearings(TRB) were used in the $2^{nd}$ model. As a result, it was found that the $2^{nd}$ model. showed better performances on the load distribution of gear tooth flank, this results stated that the output shaft bearing system could be important consideration when designing reducers for wind turbine systems.

• 한국기계가공학회지
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• 제11권6호
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• pp.195-200
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• 2012

In this study, parameters and requirements of an 120kW class monorail planetary gearbox was analysed and the adaptive planetary gearbox design was selected. The specification of the sun gear, planetary gear and carrier was set and the profile & lead was optimized. The mechanical efficiency of the optimized one and the original one was observed. Dynamo-tester system was used to observe the mechanical efficiency of the planetary gearbox. A dynamo unit was connected with the planetary gearbox which straightened through the motor by a coupling. The standard tooth shape planetary gearbox and modified tooth shape planetary gearbox were used as test pieces and the rotation speed was set from 600 to 6000rpm with 600rpm, 2.5min one step. In order to check the mechanical efficiency of the planetary gearbox, the tests were done as follows. 1) The power loss between driving motor and dynamo tester. 2) Temperature variation by different rotation speeds. 3) Noise variation by different rotation speeds.

• 한국기계가공학회지
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• 제16권6호
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• pp.15-20
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• 2017

This study analyzed the load change of the gear generated by the operation of the vehicle recliner through Finite Element Analysis. The basic model of the recliner used was a commercial product, and the effect of the seat frame was excluded. The load conditions applied to the recliner were set considering gravity, the mass of the seat's back frame, and the weight of a person. The operating mode was set to move the seat back from the vertical to the reclined position. As a result, it was found that the tooth bending amount of the gear rim and wheel increased from the cam rotation angle of 450 degrees, and a change in the contact ratio occurred. Furthermore, excessive torque fluctuations occurred in the ranges of 390 to 450 and 750 to 710 degrees. It was found that this occurred in the region of about 30 degrees before and after the point where the x-axis direction load is larger than the y-direction load. From this torque fluctuation it was determined to likely to cause chattering noise.

• 한국전자통신학회논문지
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• 제13권5호
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• pp.1023-1028
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• 2018

직접 접촉 방식의 기계적인 결합을 사용하는 기어는 접촉 마찰로 인한 소음, 진동, 발열 등의 문제가 지속적으로 제기되어왔기 때문에, 비접촉 자기(magnetic)결합을 이용한 마그네틱 기어(magnetic gear)가 제안되었다. 마그네틱 기어에 대한 연구 중 동일한 기어비에서 극수에 따라 손실의 차이가 발생함을 확인하였으며, 철손과 영구자석 와류손이 극수에 따라 일정한 경향성을 보일 것으로 예상되어 연구를 진행하였다. 본 논문에서는 마그네틱 기어의 극수에 따른 경향성을 확인하고 구체화하여 마그네틱 기어의 효율 개선 설계의 기반을 마련하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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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.

• 한국전자통신학회논문지
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• 제15권2호
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• pp.259-266
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• 2020

자기 기어는 기계식 기어와 동일하게 기어의 특성을 나타내면서 각 회전자가 접촉하지 않아 마찰에 의한 소음 및 발열, 유지보수문제에서 기계식 기어보다 유리하다. 또한 권선계자를 사용하는 회전자를 적용할 경우 기어의 출력조절은 물론, 기어비 및 위급상황에서 자체적인 구동차단까지 가능하여 자기 기어의 활용가능성은 무한하다. 하지만 권선계자를 사용할 경우 영구자석과 철심간의 흡인력에 의한 코깅토크가 나타나게 되고 이는 회전자의 진동을 유발하는 토크 리플성분의 증가로 이어진다. 따라서 본 논문에서는 권선계자를 사용하는 회전자의 토크 리플을 저감하기 위해 회전자의 다양한 형상을 분석하였으며, 자기 기어의 토크 리플을 저감하기 위한 최적의 형상을 제시하였다.

• 한국소음진동공학회논문집
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• 제25권6호
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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.

• 한국소음진동공학회논문집
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• 제14권5호
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• pp.363-369
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• 2004

Vibration/noise analysis as well as strength of gear teeth, roller bearing life. joural bearing design are considered in order to develop the high-speed machine centrifugal pump which had a speed increaser. A Campbell diagram, in which the excitation sources caused by the mass unbalance of the rotors and the transmitted errors of the gearing are considered. shows that. at the operating speed. there are not the critical speed. A high-speed machine centrifugal pump was made in order to evaluate developed speed increaser. Also, strict API standard were introduced for reliability evaluation of developed speed increaser, and performance evaluation were carried out. The result that evaluation items about bearing vibration, shaft vibration, noise, and lubrication temperature were selected, and were tested. a high-speed machine centrifugal pump were able to know what were satisfied with API standard all.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1461-1466
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• 2000

This paper investigates the noise reduction scheme in tractor cabin by using various steps of experiment. The experiments were performed in the field as well as in the lab to facilitate the detail test procedure. Some of the test results were compared with computational results. Several noise sources and paths were identified including the engine compartment (cooling fan and timing gear cover), hydraulic system and its components (hoses, tubes and there mount) and structural characteristics of the cab, window, mounting bracket and machine frame including steps. Throughout the several design changes, cab noise level was reduced from 80.2dBA to 74.8dBA.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.731-732
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• 2011

This paper shows a whole noise quality checking system for the new developed 6th speed automatic transmission manufactured in USA. Due to demand for manufacturing of the high NVH quality transmissions in the mass product line, some special checking system called EOL is adapted. This EOL system is using vibration analysis technologies. Through adapting vibration analysis technologies and functions likewise RMS, Crest Factor, Harmonics, Peak, Band, and Order tracking, various noise problems caused by wear, nick, and deformations could be successfully detected and predicted. Therefore, automatic transmissions manufactured in the USA could get high NVH quality.