• 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.

• CDE review
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• v.23 no.1
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• pp.33-37
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• 2017

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.3
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• pp.253-261
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• 2014

In this paper, vibration analysis of power differential gear train for 2.5MW wind turbine system is analyzed. which system is composed of two planetary gear set, one helical gear set and main shaft that connected by flange. Planetary gear set, helical gear set, main shaft are modeled in MASTA program and housing, torque arm, carrier, flange components are modeling by finite element method. Each models are combined by component mode superposition. To analysis of natural vibration characteristic about 2.5MW wind turbine gear train was performed and check about critical speed with wind load, mass unbalance, angle misalignment excitation frequency.

• 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.

• Tribology and Lubricants
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• v.38 no.5
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• pp.179-184
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• 2022

The power train of transmission for 21-ton grade wheel excavator makes use of a complex gear train composed of a planetary and helical gear system to drive the wheel excavator by transmitting power to the axle. The complex gear train with a shift mode is an important part of the transmission because of strength problems in an extreme environment. To calculate the specifications of the complex gear train and analyze the gear bending and compressive stresses of the complex gear train, this study analyzes gear bending and compressive stresses accurately for the optimal design of the complex gear train with respect to cost and reliability. In this article, the gear bending and compressive stresses of the complex gear train are calculated using the Lewes and Hertz equation. Evaluating the results with the data of the allowable bending and compressive stress from the stress and number of cycles curves of the gears verified the calculated specifications of the complex gear train. A computer structure analysis is performed with the 3D model of the planetary and helical gears to analyze the structure strength of the complex gear train. The results demonstrate that the durability and strength of the complex gear train are safe, because the safety factors of the bending and compressive stresses are more than 1.0.

• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.293-294
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• 2011

본 논문에서는 유성기어를 사용한 직병렬 혼합형 하이브리드 자동차(SPHEV)의 파워트레인 모델링과 하이브리드 자동차의 모드(전기자동차 모드(EV), 엔진 모드, 하이브리드 모드(HEV) 등등)변화에 따른 파워 분배 및 동특성 해석에 대하여 기술한다. 내연기관, 전동기, Energy Storage System(ESS)과 같은 구성요소들의 정격은 에너지 개념과 Electrical Peaking Hybrid(ELPH)를 이용하여 설계하였으며, 동특성 분석을 위하여 전력전자 분야 에서 널리 사용되고 있는 시뮬레이션 툴인 PSIM을 이용하여 모델링 하였다.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.5
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• pp.508-514
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• 2015

In this paper, the powertrain efficiency is analyzed for the input split type hybrid electric vehicle. For considering the powertrain loss, the power loss models of planetary gear and motor are applied. And, the mathematic equations of powertrain speed and torque are found by using the lever analogy. With the above models and equations, the powertrain efficiency is analyzed for the 0 to 180 km/h vehicle velocity range. From the analysis results, it is found that the transmission efficiency with the power loss of planetary gear is smaller maximum 2.1% than the transmission efficiency without the power loss of planetary gear.

• Tribology and Lubricants
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• v.38 no.1
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• pp.22-26
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• 2022

A 1.7-ton grade small excavator is a construction equipment that can perform various functions in limited spaces where heavy equipment cannot enter easily. Owing to the recent acceleration of urbanization, it has been used increasingly in drainage and gas pipes, as well as for road repair works in urban areas. The power train of a traveling reducer for a 1.7-ton grade small excavator utilizes a complex planetary gear system. Complex planetary gears are vital to the power train of a traveling reducer as it mitigates the fatigue strength problem. In the present study, the specifications of a complex planetary gear train are calculated; furthermore, the gear bending and compressive stresses of the complex planetary gears are analyzed to achieve an optimal design of the latter in terms of cost and reliability. In this study, the actual gear bending and compressive stresses of a planetary gear system are analyzed using a self-developed gear design program based on the Lewes and Hertz equation. Subsequently, the calculated specifications of the complex planetary gears are verified by evaluating the results with the data of allowable bending and compressive stress based on curves of stress vs. number of cycles of the gears.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.5
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• pp.138-144
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• 2012

Recent environmental issues such as exhaust gas and greenhouse effect make the agricultural machinery market takes into account the hybrid and electric propulsion technology used in automotive engineering. Generally the agricultural machinery, particularly an agricultural tractor, needs large load capacity and long continuous operating time comparing with conventional vehicles. In case of a pure electric tractor, it is necessary for considering large capacity batteries and long charging time. Therefore we take an AER extended PHEV (All Electric Range extended Plug-in Hybrid Electric Vehicle) power transmission system in developing an electric tractor in this study. First we propose a PHEV powertrain structure in order to substitute the conventional diesel engine equipped tractor. And we performed the road tests using a conventional mechanical tractor with various load conditions, which were classified and statistically treated real agricultural works. The test results were analysed with respect to the power characteristics of the power source. Finally using the test result, we designed two-stepped reduction gear ratios in the proposed an electric tractor powertrain for carrying out typical agricultural works.

• Tribology and Lubricants
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• v.37 no.2
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• pp.48-53
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• 2021

Wind energy is considered as the most competitive energy source in terms of power generation cost and efficiency. The power train of the pitch drive for a wind turbine uses a 3-stage complex planetary gear system in being developed locally. A gear train of the pitch drive consists of an electric or hydraulic motor and a planetary decelerator, which optimizes the pitch angle of the blade for wind generators in response to the change in wind speed. However, it is prone to many problems, such as excessive repair costs in case of failure. Complex planetary gears are very important parts of a pitch drive system because of strength problem. When gears are designed for the power train of a pitch drive, it is necessary to analyze the fatigue strength of gears. While calculating the specifications of the complex planetary gears along with the bending and compressive stresses of the gears, it is necessary to analyze the fatigue strength of gears to obtain an optimal design of the complex planetary gears in terms of cost and reliability. In this study, the specifications of planetary gears are calculated using a self-developed gear design program. The actual gear bending and compressive stresses of the planetary gear system were analyzed using the Lewes and Hertz equation. Additionally, the calculated specifications of the complex planetary gears were verified by evaluating the results from the Stress - No. of cycles curves of gears.