• Proceedings of the KIPE Conference
• /
• 2016.11a
• /
• pp.228-229
• /
• 2016

본 논문에서는 전기자동차에 2단 기어를 사용하여 모터와 인버터 측면에서의 효율 개선을 목표로 하고 있다. 2단 기어 시스템에서의 높은 기어비를 갖는 1단 기어는 차량의 바퀴 쪽에서의 높은 토크를 낼 수 있도록 하며, 낮은 기어비를 갖는 2단 기어는 더 넓은 범위의 속도 구간을 보여준다. 2단 기어 시스템에서 개선된 효율을 보이기 위하여 토크와 속도 그리고 효율을 고려한 변속시점을 제안한다.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2017.04a
• /
• pp.11-11
• /
• 2017

지속적인 고령화 추세에 따라 여성과 고령층의 노동력이 차지하는 비율이 높아지고 있어, 사용하기 편리한 소형농기계의 요구가 증가하고 있는 실정이다. 본 연구에서 사용한 소형 관리기는 정식 작업 전 경운, 정지 등 다양한 작업이 가능한 농기계이다. 본 연구에서는 소형 관리기에 토크 측정 시스템을 구성하였으며, 작업 중 가장 큰 부하를 받는 구굴 작업 부하를 측정하였다. 또한, 작업 시 가장 직접적으로 영향을 받는 PTO (Power Take Off) 기어의 부하 용량(load capacity)을 기어 해석 소프트웨어를 이용하여 분석하였다. PTO 기어의 부하 용량은 안전율, 피로수명을 대상으로 평가하였다. 측정된 부하 데이터는 변동 하중이므로, 부하 크기와 빈도수의 규칙적인 신호로 단순화하기 위하여 레인플로우 카운팅 방법을 사용하였으며, SWT (Smith-Watson-Topper) 방법을 이용하여 공칭 토크를 계산하였다. PTO 기어의 안전율은 ISO 6336, 피로 수명은 마이너 법칙(Miner rule)을 이용하여 계산하였다. PTO의 변속 단수 총 2단이며, 5개의 스퍼 기어로 구성되어 있다. 시뮬레이션 결과, 소형 관리기의 주행 속도 또는 PTO의 회전속도 증가에 따라 PTO에서 발생하는 평균 부하가 크게 나타났다. 또한 주행 단수 및 PTO 기어 단수가 증가할수록 기어의 안전율과 피로 수명이 감소하였으며, 특히 PTO 기어의 안전율은 접촉 응력에서의 안전율보다 굽힘 응력에서의 안전율이 급격하게 감소하였다. 소형 관리기의 PTO 수명은 주행 단수 2단, PTO 단수 2단 일 때 가장 적게 나타났다. 따라서 소형 관리기의 주행 속도와 PTO 회전 속도를 저속으로 작업하는 것이 PTO 기어의 수명에 더 유리할 것으로 판단된다.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
• /
• 2005.05a
• /
• pp.188-191
• /
• 2005

본 논문에서는 RF 플라즈마 발생 장치인 RF-Match의 기구적 최적 설계를 제안하였다. RF-Match의 정합소자 구동 기어단의 효율 개선을 위해 베벨기어를 웜기어로 대체 설계하여 백래쉬를 제거하였으며, 정합소자의 고전력 인가로 인한 아크 발생 문제의 해결을 위해 접지를 개선하여 RF-Match의 기구적 성능을 향상 시켰다.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.15 no.3
• /
• pp.17-23
• /
• 2006

The strength estimation is carried out for injection molded plastic stepped gear. The stepped gear is considered as a plate model which is fixed by two edges and freed on the other sides. The stress of common normal gear is calculated by Lewis formula which can be derived quite simply from the equation fur the stress at the root of a cantilever beam. Stress ratio(step factor) between the common normal gear and stepped gear is proposed for the ratio of the bending stress of normal gear and that of stepped gear. This study proposes the step factor added in Dupont equation which is used for strength estimation of injection molded plastic stepped gear.

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

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

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2003.07a
• /
• pp.372-377
• /
• 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 Advanced Marine Engineering and Technology
• /
• v.39 no.9
• /
• pp.895-902
• /
• 2015

In this paper, finite element analysis of a cycloidal pitch reducer for a 2 MW-class wind turbine is reviewed. The system is composed of one cycloid set, one spur gear set, an input shaft, an output shaft, and a housing. The system was also evaluated for stability by analyzing spur gear strength according to ISO 6336. An analysis of the natural vibration characteristics of the 2 MW-class wind turbine cycloid pitch reducer was performed with attention to critical speed with input mass unbalance, output mass unbalance, spur gear transmission error, cycloid gear transmission error, and excitation frequency.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.29 no.1
• /
• pp.37-44
• /
• 2016

This study is concerned with the numerical investigation of dynamic characteristics of 2.5MW-class wind turbine gearbox in which the misalignment improvement of plenary gear shafts by the flexible pins and the dynamic impact response are analyzed by the finite element method. The tooth contact between gears is modelled using the line element having the equivalent tooth stiffness and the contact ratio to accurately and effectively reflect the load transmission in the internal complex gear system. The equivalent tooth stiffness is calculated by utilizing the tooth deformation analysis and the impulse torque is applied to the input shaft for the dynamics response characteristic analysis. Through the numerical experiments, the equivalent tooth stiffness model was validated and the misalignment improvement of planetary gear shafts was confirmed from the comparison with the cases of fixed shafts at one and both ends.

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