• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.6
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• pp.8-14
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• 2001

We develop a method to analyze dynamic behavior off multi-stage gear train system. The example system consists of three shafts supported by ball bearings at the ends of them and two pairs of spur gear set. For exact analysis, the meshing tooth pair of gear set is modeled as spring and damper having time-dependent meshing stiffness and damping. The bearing is modeled as spring. The result of this analysis is compared to that of other model having mean mesh stiffness. The effect of the excitation force by the unbalance off rotor off motor is also analyzed. Finally, the change ova natural frequency of the whole system due to the change of an angle between three shafts is compared in each case, and from this analysis, the avoiding angle for design is advised.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.07a
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• pp.372-377
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• 2003

'92년부터 추진한 농업구조개선으로 시설원예 농업은 현대화 대형화되어 환기를 위한 천측창 개폐장치와 보온을 위한 커튼개폐장치의 자동화로 시설원예농업의 편의성을 증대시켰다. 천측창 동력개폐장치에 있어서는 설치개소가 많고 빈번한 작동으로 일찍이 동력개폐기 문제점이 지적되었고, 그에 따른 많은 개선이 이루어졌다 초기의 동력개폐기는 2단 웜기어 감속방식을 사용하여 동력전달효율이 낮아지고 웜기어의 마모로 고장이 잦고 수명이 짧아지는 문제가 있어 감속방식을 유성기어로 전환하여 실용화되면서 많은 발전을 이루어 왔다. (중략)

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.2
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• pp.73-80
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• 2016

To reduce the mechanical energy loss and to get the high energy efficiency, an apparatus of wave power generation inducing a consistent one way rotating motion from the wave reciprocation motions was developed and the hydraulic experiments for the real electric power production were conducted and the results were discussed. In the experiments for the shape of the buoyant tank, the efficiency of the fixed 9 cm diameter type enduring the wave plate weight was 14.6% and this was the best result for all shapes. But although the free sliding type was expected to represent a high efficiency, the experiments did not show a good result as 8.5% efficiency. Therefore, the shape of buoyant tank was decided as the fixed 9 cm diameter type in the next all tests. In the experiments for the various incident waves, when the water depth was 90 cm, the average efficiencies were measured as 3.9% in the 2nd gear, 4.9% in the 3rd gear, 4.9% in the 4th gear, 12.0% in the 5th gear, 10.0% in the 6th gear, 3.1% in the 7th gear, and 3.0% in the 8th gear. Also, when the water depth was 80 cm, the average efficiency was shown as 15.0% with 5th gear condition. Therefore the high average efficiency as 13.5% was given with 80~90 cm water depth and the 5th gear in the model.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.1077-1078
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• 2009

• Journal of the Korean Institute of Gas
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• v.24 no.6
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• pp.55-60
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• 2020

As research and development of eco-friendly vehicles are expanding worldwide, additional devices of vehicles are reduced or deleted to increase the mileage, or research is being conducted to reduce weight. Among them, the multi-stage transmission that was applied to the internal combustion engine vehicle was deleted and replaced with a reducer, and the initial driving power is secured by increasing the torque through the control of the motor output value. However, since frequent motor speed change can result in a load increase, this study attempts to develop a compact and lightweight manual two-stage reducer with a general reducer structure. Therefore, a two-speed transmission with two gear ratio was designed by inserting a large gear and a small gear in a structure with a parallel shaft to connect the gears with a V-belt in the form of a parallel shaft reducer, and setting the gear ratio of the low and high gears respectively. In addition, power performance according to the rotational speed and load of the transmission was checked through a test, and the heat generation characteristics generated during driving were checked to verify the validity of the transmission.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.78-78
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• 2017

현재 국내에 공급되고 있는 잡곡류 수확기는 보행형 예취기, 탈곡기 위주의 저능률 기계화 수준으로 고능률의 콤바인 수확기 개발이 필요하며, 특히 잡곡류가 소규모 경작지의 영세농가 위주로 재배되어 저가격의 소형 콤바인 수확기 개발이 절실히 요구되고 있다. 따라서 본 연구는 소규모 밭의 두류 및 잡곡 수확작업에 적응성이 뛰어나며, 농기계 임대사업소의 활용도를 높일 수 있고, 여성과 고령자도 쉽게 운전할 수 있어 수확작업의 노동력을 크게 절감할 수 있는 저가격의 25kW급 자주식 소형 콤바인을 개발하고자 시작기를 설계 제작하였다. 시작기의 주요부로 엔진은 25kW/2600rpm 3기통 디젤엔진을 탑재하였으며, 동력전달부는 주변속 3단, 부변속 2단의 선택맞물림 기어식의 변속장치를 이용하였다. 주행부는 궤도형으로 조향클러치와 습식 원판식 제동장치를 채용하였다. 전처리부는 선단거리 1700 mm의 디바이더와 상하좌우 수동 조절되는 회전속도 약 42 rpm의 정오각형 릴로 구성하였으며, 전처리부의 최대 승강높이는 740 mm이었다. 작물이송부는 돌기부착 오거와 체인컨베이어로 구성되어 있으며, 탈곡부는 단동형 축류식의 직경 440 mm, 길이 1180 mm의 급동과 높이 65 mm, 지름 10 mm의 46개 강봉형 급치, 격자형 수망으로 구성하였으며, 회전속도는 약 325 rpm으로 작동하도록 하였다. 선별 정선부는 요동 송풍선별식으로 곡립판, 볏짚체, 곡립체, 송풍팬으로 구성하였고 송풍팬의 회전속도는 약 850 rpm, 요동진동수는 약 5.8 Hz로 작동하도록 하였다. 곡물이송부와 재처리부는 수평이송 외경 103 mm, 수직이송 외경 110 mm의 피치가 모두 82 mm인 스크류컨베이어를 이용하였으며, 곡물탱크는 용량이 250 로 2개의 배출구로 곡물을 포대에 담도록 하였다. 그 외 시작기는 운전조작부, 유압장치부, 전기장치부 등을 갖도록 설계 제작하였다. 전체적인 기체의 크기는 길이${\times}$폭${\times}$높이 $3935{\times}1900{\times}2440mm$이었으며, 기체 중량은 약 1753 kg이었다. 콩 대상 기초 성능시험 결과 시작기의 작업속도는 약 0.5 m/s, 작업능률은 약 11 a/h로 나타났다.