• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1998.05a
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• pp.25-30
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• 1998

최근 산업이 발달함에 따라 기계회전계는 고속화, 정밀화 그리고 고부하에 따른 성능 향상과 내구성이 요구되고 있으면 기어 구동계는 강성, 효율향상, 저진동, 저소음 기어의 개발이 요구되고 있다. 그러나 기어는 제작오차, 조립오차, 치의 변형, 마모등으로 인하여 전달오차가 발생하게된다. (중략)

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.12
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• pp.1005-1011
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• 2016

The fundamental reason for gear noise is transmission error. Transmission error occurs because of STE (static transmission error) and DTE (dynamic transmission error), while a pair of gears is meshing. These errors are generated by the deflection of the teeth and the friction on the surface of the teeth. In addition, the vibration generated by transmission error leads to excited bearings. The bearings support the shafts, and the noise is radiated after exciting the gear casing. The analysis of the contact stress in helical gear tooth flanks indicates that it is due to impact loading, such as the sudden engagement and disengagement of a gear. Stress analysis is performed for different roll positions, in order to determine the most critical roll angle. Dynamic analysis is performed on this critical roll position, in order to evaluate variation in stresses and tooth contact force, with respect to time. In this study, transmission error analysis was implemented on a spur and helical gear with involute geometry and a modified geometry profile. In addition, in order to evaluate the intensity of impact due to sudden engagement and significant backlash, the impact factor was calculated using the finite element analysis results of static and dynamic maximum bending stresses.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.2
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• pp.169-177
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• 2017

In this paper, classification of spall and crack faults of gear teeth is studied by applying the ensemble empirical mode decomposition(EEMD) for the gear transmission error(TE). Finite element models of the gears with the two faults are built, and TE is obtained by simulation of the gears under loaded contact. EEMD is applied to the residuals of the TE which are the difference between the normal and faulty signal. From the result, the difference of spall and crack faults are clearly identified by the intrinsic mode functions(IMF). A simple test bed is installed to illustrate the approach, which consists of motor, brake and a pair of spur gears. Two gears are employed to obtain the TE for the normal, spalled, and cracked gears, and the type of the faults are separated by the same EEMD application process. In order to quantify the results, crest factors are applied to each IMF. Characteristics of spall and crack are well represented by the crest factors of the first and the third IMF, which are used as the feature signals. The classification is carried out using the Bayes decision theory using the feature signals acquired through the experiments.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.10a
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• pp.50-55
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• 1995

진동하는 경계면의 진동장 및 음장을 재구성하기 위하여 음장측정치 및 경계요소법을 이용한 음향 홀로그래피 방법을 연구하였다. 특히, 측정잡음 및 전달행렬의 특이성에 의해 발생하는 재구성 오차에 대하여 고찰하였다. 재구성의 정확도를 나타내기 위하여 전달행렬의 특이인자를 도입하였다. 예제로 한면이 진동하는 직육면체 상자를 고려하였다. 결과로부터 매우 작은 측정잡음에 대해서도 전달행렬의 특이성 재구성 오차가 크게 발생하며, 측정위치에 따라 전달행렬의 특이성이 크게 영향 받음을 확인하였다. EfI방법을 이용하여 최적의 측정점을 선택한 결과 전달행렬의 특이성을 크게 줄일 수 있었으며 이때 측정점의 위치는 가진주파수에 관계없이 큰 음장이 형성되는 소음원의 근접장에 위치함을 알 수 있다. 또한 저주파 가진에 비해 고주파 가진이 작은 특이인자값을 나타내며, 따라서 재구성 오차가 작음을 알 수 있었다. 재구성장의 정밀도를 향상시키기 위하여, 부가적으로 진동장의 norm을 제한하는 적절화방법을 도입하였다. 모델의 최소자승오차를 최소화 하는 최적의 적절화변수를 추정하여 이로부터 재구성 오차를 줄일 수 있었다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.284-284
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• 2003

• The Journal of the Acoustical Society of Korea
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• v.20 no.6
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• pp.75-81
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• 2001

In this paper we analyzed the localization error of near-field detection algorithm in the sea. The near-field detection algorithms using triangulation and wavefront curvature basically assume a signal in two dimension of bearing and range. But the assumption causes localization error because there is three dimension of bearing, range, and depth in the sea. Even through three dimensional effect is considered, the localization error is occurred if multipath propagation in the sea is ignored. To analyze the localization error in the sea, we simulate the near-field localization using acoustic propagation model and focused beamforming considering wavefront curvature. The simulation results indicate that localization error always occurs in the sea and the error varied with sound velocity profile, water depth, bottom slope, source range, etc.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.5
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• pp.206-212
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• 1999

In this paper, the transmission error of a atar type Epicyclic Gear Train (EGT) has been studied. Dynamic analysis has been executes calculate the rotation angle of the input and output shafts at various loads. Transmission Error of EGT has been measured to compare with the analysis results. There are qualitative similarity between the experimental and analytical results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.689-690
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• 2013

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.359-362
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• 2000

ANC시스템에 있어서 현재 많이 이용되고있는 Filtered-X LMS 알고리즘에서 2차 음원과 제어점간의 임펄스응답은, 미리 동정하여 사용하는 것이 일반적이지만, 2차 음원과 제어점간의 전달특성이 이후에 변화할 경우, 실제의 전달함수와 적응에 이용한 전달함수간에 모델링 오차가 발생하게된다. 이 모델링 오차에 의하여 알고리즘은 오동작을 일으키고, 시스템은 불안정하게 되기도 한다. 따라서, 본 연구에서는 참조신호가 랜덤신호일 경우에 발생하는 모델링 오차와 Filtered-X LMS 알고리즘의 오동작에 관한 이론식을 도출하고, 시뮬레이션을 통하여 이를 입증하였다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.6
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• pp.470-475
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• 2014

In the past, transmission error(T.E.) has been identified as one of the main sources of gear whine noise, which cause serious passengers irritation at high frequency. In this study, to identify the correlation of the T.E. and gear whine noise, a T.E. measuring system was developed. By comparing the T.E. and gear whine noise level, T.E. target value which can represent the gear noise was proposed. The conclusions are followed: (I) It is possible to measure T.E. of the gear pairs (II) Similar trends are observed between T.E. and gear whine noise. (III) By observing the T.E. pattern, presence of sideband noise can be predicted. (IV) Proposed T.E. target value can be adopted to the gear manufacturing for gear noise quality management.