• 드라이브 ㆍ 컨트롤
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• 제14권1호
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• pp.1-7
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• 2017

The power train of a concrete truck mixer reducer includes differential planetary gears to get a large reduction ratio for operating the mixer drum in a compact structure. These differential planetary gears are a very important part of the mixer reducer where strength problems are the main concern. Gear bending stress, gear compressive stress and scoring failure are the main concerns. Many failures in differential planetary gears are due to the insufficient gear strength and resonance problems caused by major excitation forces such as gear mating failure in the transmission. In the present study, where the excitation frequencies are the gear tooth passing frequencies of the mating gears, a Campbell diagram is used to calculate differential planetary gear critical speeds. Mode shapes and natural frequencies of the differential planetary gears are calculated by CATIA V5. These are used to predict gear resonance failures by comparing the working speed range with the critical speeds due to the gear transmission errors of the differential planetary gears.

• 드라이브 ㆍ 컨트롤
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• 제14권4호
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• pp.71-78
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• 2017

The power train of hydro-mechanical continuously variable transmission (HMCVT) for 8-ton class forklift includes hydro-static units, hydraulic multi-wet disc brake & clutches and complex helical & planetary gears. The helical & planetary gears are key components of HMCVT's power train wherein strength problems are the main concerns including gear bending stress, gear compressive stress, and scoring failure. Many failures in power train gears of HMCVT are due to the insufficient gear strength and resonance problems caused by major excitation forces, such as gear transmission error of mating gear fair in the transmission. In this study, wherein excitation frequencies are the gear tooth passing frequencies of the mating gears, a Campbell diagram is used to calculate the power train gears' critical speeds. Mode shapes and natural frequencies of the power train gears are calculated by CATIA V5. These are used to predict resonance failures by comparing the actual working speed range with the critical speeds due to the gear transmission errors of HMCVT's power train gears.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.803-806
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• 2002

This paper estimated the stability of centrifuge as its rotating speed compared with the natural frequency of cylinder and screw by finite element analysis. It shows that the one of exciting causes is the tooth passing frequency of input and output parts by the periodic characteristics of transmission error due to an planetary gear having three stages. Also, it proposed the critical speed of cylinder and screw by the Campbell diagram.

• Tribology and Lubricants
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• 제35권1호
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• pp.71-76
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• 2019

The differential planetary gear reducer as a main component of the concrete mixer driving mechanism requires a strong torque to mix concrete compounds. As this component is currently dependent on imports, it is necessary to develop it by conducting a study on vibration analysis and the resonance problem. The noise and vibration of a concrete mixer reducer increase owing to the transmission error of planetary gears, and the damage of components occurs owing to the problems in design and production. In this study, the tooth-passing frequency is calculated to evaluate the noise and vibration of a mixer reducer, and a fast Fourier transform (FFT) analysis is conducted through a vibration test using an acceleration sensor. The vibration of the reducer is measured at three points of input and output of the shaft and planetary gear housing with fixed and variable revolutions per minute. The operating conditions of gears and bearings are evaluated by performing the FFT analysis, and the resonance problem is verified. The results show that No. 1 pinion and ring gears revolve disproportionately. The amplitude values appear high, and the wear of tooth faces occur in tooth-passing frequencies and harmonic components of No. 1 and No. 2 pinion-ring gears. Therefore, we conclude that design changes in the reducer and a correction of tooth profiles are required.

• Journal of Advanced Marine Engineering and Technology
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• 제35권6호
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• pp.786-795
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• 2011

본 연구에서는 블레이드, 증속기, 발전기, 케이스를 포함한 풍력 발전시스템의 진동 모델을 개발 하였다. 특히 유성기어열에서의 유성기어는 유연핀에 지지가 되어 있는데, 이는 비틀림만을 고려하지 않고 유성기어의 회전 방향의 접선방향으로의 병진 운동을 고려하였으며, 풍력발전시스템이 마운트에 지지되어 있는 특징을 고려하여 케이스에 의한 운동을 포함 하였다. 풍력발전 시스템의 진동특성을 파악하기위하여, 풍하중, 불평형, 치합전달오차에 등에 의한 자려가진원을 구하였고, 운전속도 범위 내에서 위험속도 분석을 하였다. 위험속도해석결과, 2단 치통과 주파수에 의해서 81.2Hz, 104.7Hz 모드에서 공진이 발생하며, 3단 치통과 주파수에 의해서 264.5Hz, 377Hz, 424.6Hz 모드에서 공진이 발생하는 것을 알 수 있었다. 또한, 공진이 발생하는 진동모드를 분석하여 진동저감 대책을 수립하였다.

• 드라이브 ㆍ 컨트롤
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• 제19권4호
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• pp.1-9
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• 2022

The structure and operating principle of the 2-speed shift reducer were explained, the allowable bending stress value of the material was compared with the analysis result through FM structural analysis program, and the average stress distribution value of von Mises was performed on the gear root atmosphere. The structural safety of the 2-speed planetary gear reducer was verified through FM structural analysis. The natural frequency was calculated by applying the specifications of the planetary gears of the 2-speed gearbox, and the critical speed of resonance was calculated by calculating the natural frequency and the transmission error of the engaged gear pair. As a result of analyzing the critical speed, since it is formed higher than the actual operating speed range, it is considered safe because there is no resonance problem due to the suggested specifications of the planetary gears of the 2-speed shift reduction.