• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.11
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• pp.1477-1482
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• 2011

Using a one-way clutch has been reported to be very effective in reducing the vibration of gear pairs. However, study on the effect of using a one-way clutch has been based on numerical analysis only, and no experimental study has yet been executed. Hence, in this study, experiments to verify the effectiveness of using a one-way clutch to reduce the torsional vibration have been executed. Dynamic responses over a wide range of speeds have been compared for various numbers and positions of the clutch. The results of the experiments verified that a one-way clutch is effective in reducing the vibration by decreasing the tooth mesh vibration as well as the vibration transmitted from the input shaft.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.12
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• pp.953-960
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• 2020

This paper presents an optimization of gear web design used in a main gear train of an engine reduction gearbox for a rotorcraft. The optimization involves the minimization of a total weight, transmission error, misalignment, and face load distribution factor. In particular, three design variables such as a gear web thickness, location of rim-web connection, and location of shaft-web connection were set as design parameters. In the optimization process, web, rim and shaft of gears were converted from the 3D CAD geometry model to the finite element model, and then provided as input to the gear simulation program, MASTA. Lastly, NSGA-II optimization method was used to find the best combination of design parameters. As a result of the optimization, the total weight, transmission error, misalignment, face load distribution factor were all reduced, and the maximum stress was also shown to be a safe level, confirming that the overall gear performance was improved.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.6
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• pp.806-815
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• 2010

Gear trains are combined with the planetary gear units and helical gear units. It is known that the combination type is decisive to the system performances of the transmissions. In this paper, within the commonly used range of the design requirements for medium and large scaled (1~8 MW) wind turbines, the transmission characteristics of the typical layouts of the gear train are investigated. According to the international standard by ANSI/AGMA/AWEA 6006-A03, the gear boxes are basically designed and compared with respect to the system lifes of 99% reliability, total weight, the power densities, overall diameter/length and the maximum stresses of the gear teeth. With these comparison works, the characteristics of the layouts of gear trains are discussed.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.6
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• pp.45-51
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• 2002

The existing methods to split overall gear ratio of the cylindrical multi-stage gear train have their own limitations to be used in practical design and are also problematic to be implemented in a formalized algerian. This paper proposes two types of new methods to find gear ratios best approximating the overall gear ratio. The proposed methods are quite general to be applied to the gear train having any number of stages, and offer a considerably good result in a very short time. The first method uses the random search method and the second one is based on the simulated annealing algorithm. The proposed algorithms are expected to be very useful not only as an independent program to split overall gear ratio, but also as a desist sub-module for the integrated desist system of multi-stage gear drives.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.687-692
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• 2002

This paper reviews the existing methods to divide the gear ratios of a multi-stage gear train, and proposes a simulated annealing-based algorithm to find the best gear ratios. The existing methods have their own limitations to be used in practical design, and are also problematic to be automated in a design system. However, the proposed algorithm is a general one which can be applied to gear trains having any number of stages, and offers a satisfactory result in a very short time. It is expected to be useful as a design sub-module of the design system for multi-stage gear drives.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1991.06a
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• pp.70-75
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• 1991

기어는 기계시스템에서 동력전달 및 운동전환을 담당하는 기본 요소로 공작기계, 건설기계, 농업기계 등의 산업기계와 항공기, 자동차, 선박등의 운송분야, 사무용 및 계측기기 등 산업전반에 걸쳐 사용되고 있으며, 최근에는 로보트를 위시한 자동화 장치의 구동 및 동력전달 장치로 사용되고 있다. 최근의 기어시스템은 기계류의 일반적인 경향인 고속, 고부하, 결량화 추세에 따라 고정밀, 소형화되어 가고 있으며 부하한계에 가깝도록 큰 하중에 견딜것이 요구되고 있다. 따라서 기어의 설계 및 제작시, 여유있는 설계가 허용되지 않으며 정밀성을 높이기 위한 설계로, 설계인자의 세분화가 요구되어지고 있다. 국제적으로 통용되고 있는 강도설계 규격에서 면압강도시 표면상태계수(Surface condition factor)를 정의하고 있다. 본 연구에서는 동력순환식 기어 시험장치를 이용하여 표면처리 상태가 다른 3종류(열처리를 하지 않은 기어, 침탄 및 고주파 표면 열처리한 기어)의 스퍼어 기어를 이요하여 회전수별 표면거칠기의 변화 상태를 고찰하고, 변수를 응용하여 물리적 의미를 파아갛고, 윤활해석을 통한 윤활조건과 치면상태와의 상호 관계에 대하여 고찰해 보고자 한다.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.922-923
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• 2015

풍력발전기는 2000년대 초반에 발전기 회전자 직경이 80m에 이르는 2MW급 풍력발전기들이 여러 회사에서 개발되면서 경제성 및 신뢰성도 향상되어 비약적인 발전을 이루게 되었다. 풍력발전시장의 신규발주와 설치장소가 한계점에 이르게 됨으로써 경제성이 뛰어난 대형 풍력발전기의 필요성이 대두되고 있다. 이와 같이 풍력발전기의 대형화 추세는 대형화를 통해 에너지 효율의 증대뿐만 아니라 단위 용량 당 건설비 및 설비비 절감이 가능하기 때문에 풍력발전기 대형화를 위한 기술개발이 활발히 진행되고 있다. 하지만 현재 풍력발전기에 사용되는 기계적 기어박스는 윤활유 주입 및 보수 점검의 문제점이나 소음, 진동, 마찰에 의한 열 발생 등의 문제점들을 가지고 있다. 이러한 문제점을 해결하기 위하여 기계적 기어박스를 마그네틱 기어를 이용하여 구성하고자 한다. 따라서 본 논문에서는 마그네틱 기어를 이용하여 10MW급 풍력발전기의 기어박스를 설계하고 그 가능성을 검토하고자 한다.

• Journal of Drive and Control
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• v.10 no.2
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• pp.30-36
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• 2013

Tractor is a farm vehicle that is designed to provide a high tractive effort at low speed. It is used for versatile agricultural tasks such as hauling a trailer, tillage, mowing and construction work. Most older tractors use a manual transmission. However, as the intensity of work increases, tractors equipped with automatic transmission become popular due to the work convenience. In order to give the operator a large degree of control in field work, 24 gears with automatic 8-speed and manual 3-speed are arranged in transmission. This paper deals with the gear train that is designed for 8-speed automatic transmission by the engagement of multi-disk clutches. The gear ratio for each speed as well as power transmission mechanism is analyzed through velocity analysis. In addition, constraints of mesh gear ratio are derived by investigating the power flow path in velocity diagram for the given 8-speed gear ratio.

• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.1
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• pp.132-138
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• 1999

This paper addresses an analytical approach to the mechanical error analysis of gear train and tolerance design and manufacture of gear train in restricted space considering motor driving torque, driving system inertia, motor acceleration, motor rotor inertia and friction torque. The gear train is designed to have optimum gear ratio in restricted space and each gear is manufactured to have the lowest weight and each gear tooth is heat-treated to have robustness. Based on the small difference between the mechanical error analysis and measurement, gear train design with optimum gear ratio and restricted space and robustness is proposed

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.3
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• pp.237-243
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• 2012

The thickness optimization of the gearbox housing for 5MW wind turbine is carried out with the help of the efficient structure analysis model and the approximation model of objective function. Wind turbine gearbox is a complex structural system composed of a number of gear trains, shafts, bearing and gearbox housing, requiring a tremendous number of elements for the structural analysis and design. In this paper, an effective analysis and design model considering the tooth stiffness of helical gears is proposed. It enables to significantly reduce the total element number and the analysis time. Through the numerical optimization of housing thickness making use of the effective gearbox model and the approximate model of objective function, the total weight of the gearbox housing is minimized. It has been observed from the numerical experiment that the approximation model is reliable and the optimization result is acceptable and verified analysis.