• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(I)
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• pp.188-192
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• 2002

In this study, Curve dependent wheel flange lubricator with grease spray type is introduced and checked and estimated a point of view reducing wheel flange wear and noise in the curve. Advantage of curve dependent wheel flange lubricators with grease spray type is found on the basis of the result of field test applied to KNR No. 1 Line(reconstruction car).

• 한국자동차공학회논문집
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• 제5권2호
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• pp.120-126
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• 1997

In this study, an effective estimation method of wheel acceleration is presented. The wheel acceleration is mainly used in the ABS(anti-lick brake system) and the TCS(traction control system). The wheel acceleration is a derivative term of the wheel speed which is generally measured by the wheel speed sensors. The results of a simple differentiation of the signal and an observation of the signal by Kalman filter show that Kalman filter has better performance than the simple differentiation. The differentiated sine signal which is contaminated with random noise shows a rugged signal compared with the signal which is filtered by the Kalman filter. The covariance of the differentiated signal is higher than that of the Kalman-filtered signal, too. The presented Kalman filter technique shows an effective way of solution to get the estimated wheel acceleration value which is sufficient to be applied to ABS or TCS control algorithms.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.6-12
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• 2010

철도소음은 공기역학적 소음, 차륜과 레일의 상호작용에 의한 전동소음과 고가구조음으로 나눌 수 있다. 열차의 속도한계에 의해 재래철도의 주소음원은 전동음이라고 알려져 있으며, 전동음에 대한 많은 연구가 이루어졌다. 또한 전동음을 주소음원으로 하여 철도소음에 대한 예측모델을 제시하고, 철도소음의 전파특징에 대한 연구가 다수 이루어졌다. 또한 근래에는 고가선로에 대한 고가진동음에 대한 연구가 진행되고 있다. 한편, 본 연구에서는 국내 고가철교에 거의 설치되어 있지 않은 방음터널에 대한 효과를 파악하고 앞으로 설치가 예상되는 고가철교 방음터널에 대한 설계 자료를 확보하기 위한 기초연구를 수행하였다.

• 한국철도학회논문집
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• 제11권2호
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• pp.176-181
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• 2008

철도차량의 차륜과 레일 시스템을 모사한 스킬소음 발생장치를 통해 실험을 수행하여 관련 원리를 실험적으로 증명하고 스킬소음 발생 메커니즘에 대한 체계적인 연구를 수행하였다. 이를 위해 스킬소음발생 메커니즘 연구를 소음원-전달계-반응계의 단계별로 진행하였다. 또한 차륜과 레일간의 스틱-슬립 운동에 의한 상대속도 또는 미끄러지는 수준과 마찰결과로서 계산되는 크립곡선과 발생 음압을 시간 및 주파수 영역에서 관찰하여 스킬 소음이 발생하는 조건을 살펴보았다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1889-1893
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• 2000

During the test drive of developing vehicle, a low frequency vibration of sprung mass on front outer wheel has been frequently observed in cornering with some speed. The purpose of this paper is to investigate the low frequency vibration of the sprung mass. The analysis result shows that the low frequency vibration is caused by sudden migration of the center of gravity of vihicle and it is determined by geometric points of suspension.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 춘계학술대회 논문집
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• pp.65-66
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• 2010

To improve the gear noise quality, gear tooth grinding machine are widely used in automotive industry. While using the gear profile grinding machine to improve the gear tooth quality of the transmission, several defects such as chattering, tooth waves that cause the gear noise occasionally happened. But it is very difficult to solve that problem, because there is no one who knows the setting up the optimal grinding condition appropriately. The abnormal manufacturing conditions which make the gear noise make the engineer to spend a lot of time, effort, and money. Due to demands for solving the serious abnormal gear noise happened in the new FF 6th stage automatic transmission in the mass product stage, the vibration checking process in the worm wheel axis, work rotation and fixed axis of the grinding machine were adapted to find the root causes. As a result, gear profile wave are affected by the work rotation axis's unbalance which is caused by worm wheel feeding speed. And a primary and the secondary grinding feeding speed, cutting oil, work fixed forces are also proved as the important factors. After setting up the grinding condition reported in this paper, it was adapted successfully to the grinding machine to manufacture the new FF 6th speed automatic transmissions' output gear. The gear noise was dramatically disappeared and the process and results will offer good guides to the engineers who manufacture the gear with the grinding machine.

• 한국소음진동공학회논문집
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• 제20권7호
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• pp.665-671
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• 2010

To improve the gear noise quality, gear tooth grinding machine are widely used in automotive industry. While using the gear profile grinding machine to improve the gear tooth quality of the transmission, several defects such as chattering, tooth waves that cause the gear noise occasionally happened. But it is very difficult to solve that problem, because there is no one who knows the setting up the optimal grinding condition appropriately. The abnormal manufacturing conditions which make the gear noise make the engineer to spend a lot of time, effort, and money. Due to demands for solving the serious abnormal gear noise happened in the automatic transmission in the mass product stage, the vibration checking process in the worm wheel axis, work rotation and fixed axis of the grinding machine were adapted to find the root causes. As a result, gear profile wave are affected by the work rotation axis's unbalance which is caused by worm wheel feeding speed. And a primary and the secondary grinding feeding speed, cutting oil, work fixed forces are also proved as the important factors. After setting up the grinding condition reported in this paper, it was adapted successfully to the grinding machine to manufacture the new automatic transmissions' gear. The gear noise was dramatically disappeared and the process and the results will offer good guides to the engineers who manufacture the gear with the grinding machine.

• 한국소음진동공학회논문집
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• 제12권10호
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• pp.758-765
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• 2002

KITECH and ODS performed a study of internal and external noise prediction of the Korean high speed prototype test train(HSR 350X). The object of this study was 3 kinds of cars, trailer car(TT2), motorized car(TMI ) and power car(TPI) and the predicted noise was for the two different driving speeds in free field and tunnel conditions. Data of carbody design and noise sources were delivered from manufactures. Some of noise sources which were not available in the project team, were chosen by experiences of ODS. Internal noise level of each car was predicted for two cases i.e, at 300 km/h and 350 km/h. In addition sound transmission path and dominant noise sources were also investigated for each section of the car, which is circular shell typed part of whole carbody. In case of TT2, the dominating sound transmission path is the (floor in terms of structure-borne noise and air-borne noise. The main noise sources are structure-borne noise from the yaw-damper and air-borne noise from the wheel/rail contact, whereas the dominating sound transmission path of TMI are floor and sidewall below the window in terms of structure-borne noise. The main noise sources of TMI are structure-borne noise from motor/gear unit and the yaw-damper in the free field, and air-borne noise from the wheel/rail contact and structure-borne noise from motor/gear unit in the tunnel. Through the external noise prediction for the KHST test train formation, the noise form the wheel/rail contact is estimated as one of the major sources. In addition, the noise specification of sub-component was proposed for managing each sub-surpplier to reach the KHST noise requirement. The specification provide the sound power of machinery part and transmission loss of component of carbody structure. The predicted noise level in each case exceeded the required limit. Through this study, the noise characteristics of the test train were investigated by simulation, and then the actual test will be performed in near future. Both measured and calculated data will be compared and further work for noise reduction will be continued.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.917-923
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• 2002

KITECH and ODS performed a study of internal and external noise prediction of the KHST test train. The object of this study was 3 kind of cars; trailer car(TT2), motorized car(TM1) and power car(TP1) and the predicted noise was calculated for the two different driving speeds in free field and tunnel conditions. Data of carbody design and noise sources were delivered from each manufactures. Some of noise sources which were not available in project team, were chosen by experiences of ODS. Internal noise level of each car were predicted for two cases i.e, at 300 km/h and 350 km/h. In addition sound transmission path and dominant noise sources were also investigated of each section of car, which is circular shell typed part of whole carbody. In case of TT2, the dominating sound transmission path is floor in terms or structure-borne noise and air-borne noise. The main noise sources are structure-borne noise from the yaw-damper and air-borne noise from the wheel/rail contact, whereas the dominating sound transmission path of TM1 are floor and sidewall below the window in terms of structure-borne noise. The main noise sources of TM1 are structure-borne noise from motor/gear unit and the yaw-damper in the free field, and air-borne noise from the wheel/rail contact and structure-borne noise from motor/gear unit in the tunnel. Through the external noise prediction for the KHST test train formation, the noise form the wheel/rail contact is estimated as one of the major sources. In addition, the noise specification of sub-component was proposed for managing each sub-surpplier to reach the KHST noise requirement. The specification provide the sound power of machinery part and transmission loss of component of carbody structure. The predicted noise level in each case exceeded the required limit. Through this study, the noise characteristics of the test train were investigated by simulation, and then the actual test will be performed in near future. Both measured and calculated data will be compared and further work for noise reduction will be continued.

• 소음진동
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• 제7권6호
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• pp.1001-1006
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• 1997

Railroad noise is one of the main causes of environmental impact. Whenever a new railroad line is planned or a housing project near an existing railroad is proposed, an estimate of the relevant noise levels is usually required. For this, it is necessary to quantify those paramters that affect the railroad noise. This paper presents an accurate prediction of railroad noise.