• 한국기계가공학회지
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• 제15권5호
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• pp.48-56
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• 2016

In this paper, we analyze the power flow of an eight-speed automatic transmission by using a lever analogy for the manufacturing of planetary gears. The results indicate that the engine power is passed down to the carrier and ring gear in the first double pinion planetary gear (DPPG1), and to the sun gear, carrier, and ring gear in DPPG3 for the first speed. Although the power flow is similar in the second speed, the power circulation occurs in the second single pinion planetary gear (SPPG2). For the third speed, the engine power is passed from the carrier to the ring gear in DPPG, at which point the power is split between the sun gears of SPPG2 and DPPG3.

• 한국기계가공학회지
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• 제15권5호
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• pp.66-72
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• 2016

Gearboxes are mechanical components that transmit power by adjusting input and output speed and torque. Their design requirements include small size, light weight, and long lifespan. We have investigated the effects of carrier pinhole position error on the load sharing and load distribution characteristics of a planetary gear set with four planet gears. The simulation model for a simple planetary gear set was developed and verified by comparing analytical results with a putative model. Then, we derived the load sharing and load distribution characteristics under various pinhole position error conditions using the prototypical simulation model. The results showed that the mesh load factor and face load factor increased with the pinhole position error, which then influenced the safety factor for tooth bending strength and surface durability.

• 한국소음진동공학회논문집
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• 제24권7호
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• pp.549-554
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• 2014

In general, there has been a lot of research concerned about the gear noise known to be proportional to gear transmission error for external gears likewise spur, helical gear, and hypoid gears. But, In the case of planetary gear set, gear noise study is insufficient because of the difficulty of designing, manufacturing, and understanding of its mechanical system. This study is aimed to develop the transmission error measurement equipment for the planetary gear sets used in the automatic transmission. By comparing the results of the transmission error and noise objectively, user could select the optimized planetary gear set which has quiet noise level before manufacturing the automatic transmission.

• 한국기계가공학회지
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• 제19권10호
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• pp.31-35
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• 2020

Hydraulic winches for transportation and logistics in the shipbuilding and marine plant fields require multi-stage planetary gear modules with high gear ratios. Due to environmental conditions in the ship, durability is crucial. Further, we are currently relying on foreign products. The development of domestic technology will reduce cost, save time, and improve the export market. Thus, we developed a multi-stage planetary gear module for a hydraulic winch and evaluated its performance through several tests of the hydraulic brake torque, maximum torque, and load endurance.

• Journal of Advanced Marine Engineering and Technology
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• 제34권6호
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• pp.806-815
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• 2010

풍력발전기용 증속기는 유성기어시스템과 헬리컬기어(또는 스퍼기어) 쌍으로 구성된다. 본 연구에서는 AGMA2001 및 ISO281기준으로 설계된 기존 및 제안된 기어열로 구성된 기어트레인들에 대하여 동력전달 특성들을 비교 분석하였다. 기어트레인의 레이아웃 설계는 기어트레인의 총중량, 출력밀도, 99% 수명시간, 최대 기어 굽힘/면압응력이 산출되었다. 설계에 사용된 설계요구조건들은 블레이드 접선속도 40 ~ 100 m/s, 1000 ~ 1800 rpm 의 발전기 입력속도, 그리고 1 ~ 8 MW의 동력 범위이다. 따라서 본 연구에서 도출된 기어열의 특성들은 기어트레인의 고 신뢰성/초 경량화 설계에 기초자료로 활용될 수 있다.

• Tribology and Lubricants
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• 제38권1호
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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.

• 한국기계가공학회지
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• 제10권4호
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• pp.38-43
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• 2011

Industrial reducer is in general use to Deck Crane. High-precision and high-efficient reducer is minimized the power-loss and energy-loss of a machine. So it contribute the price reduction and life extension. Reducer is usually using the Planetary gear reducer. Planetary gear reducer is composed the sun gear, planet gear, internal gear and casing. Industrial reducer's wear and breakage have a short-life. To solve this problem, it is using the profile-shifted-gear or tooth modification. This study was carried out the effect of addendum modification coefficient on tooth fillet bending strength to planetary reducer. Tooth fillet bending stress is calculate. And all parameter were expressed the function of addendum modification coefficient. And then stress concentration factor of tooth fillet curve was express the function of addendum modification coefficient using comparison between theory and finite element analysis.

• Tribology and Lubricants
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• 제29권6호
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• pp.378-385
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• 2013

An epicyclic gearing system is compact and lightweight. However, it is difficult to share the driving force equally because the system has closed gear trains with multiple driving points, and it always has geometrical errors in the elements. Thus, in the case of planetary gears, the first problem is how to distribute the load evenly to the numerous planets. The method widely used abroad for this purpose is to utilize the elastic deformation of the components of the structure. However, the deflection is very complicated, and it is very easy for vibration problems to occur because of the decrease in the natural frequencies. Therefore, to equalize the load on the planets, this paper discusses the principle and theory behind the functioning of a floating intermediate ring. This magnifies the displacement of a planet's center arising from the equilibrium of the load and the lubricating film pressure, which improves the compliance of the planets. The results show that load equalization of the planets is possible through this improvement in their compliance.

• 한국기계가공학회지
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• 제15권6호
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• pp.115-121
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• 2016

The aircraft flight control system controls an aircraft's direction and flying attitude, and actuators are key components of control systems. Actuators can be classified as Geared Rotary Actuator (GRA) and Ball Screw Actuator (BSA). GRA is used in mid-sized aircraft, and BSA is used in larger aircraft. A two-stage differential GRA model was suggested in this paper, and structural analysis and performance tests were performed. According to the analysis and experiment, the stiffness of the two-stage differential GRA was 17.57% higher than that of the conventional GRA, and the structural safety was improved.

• 대한기계학회논문집A
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• 제24권10호
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• pp.2619-2627
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• 2000

In this paper, the vibrational characteristics of a foot mount type gearbox for epicyclic gear train have been studied. The modal parameters and mode shapes of a gearbox have been computed using AN SYS code. Modal testing was carried out to verify the FEM analysis model. It has been shown that the analysis results are in good agreements with the experimental results. Harmonic analysis has been executed to verify the effect of thickness variance of gearbox housing on the modal response. Analyzing the calculated results, some guides for optimal vibration response has been deduced.