• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.172-177
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• 2004

A planetary gear trains has characteristics in compactness, power transformation ability and constant meshing. Usability is increased in applications of auto transmission and industrial gearbox. Study on optimum design of planetary gear train has been progressed on minimization of weight, miniaturization of planetary gear train and improvement of high strength. There are demands of study for the planetary gear train required long lift estimation In this wort being considered life, strength, intereference, contact ratio and aspect ratio, the optimum design algorithm is proposed to reduce the volume of planetary gear train with transferring the same amount of power. In the design of algorithm for planetary gear train, the determination of teeth number is separated to achieve simplicity and the simulated annealing method as a global optimal technique is used for optimal design method.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.311-314
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• 2008

The volume and size of the wind turbine gearbox has been increased with increasing transmitted power. The optimal sizing of gearbox is important due to limited space on the nacelle. The power-split type planetary gear train has been regarded as a better solution than conventional type from the point of view of the volume and weight. The purpose of this paper is to optimize the volume and weight of the gearbox by the analysis of structural characteristics and evaluation of strength of the power-split type planetary gear train.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.929-934
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• 2007

Various methods to improve the planetary gear noise in the vehicle were introduced. And planetary gear systems were analyzed Therefore a common thing among the different planetary gear systems which generate the gear noise in the vehicle was founded. Most importantly, a frequency versus vibration level map was introduced and a predictive method, which is considering the masking effect, to design the planetary gear sets in the concept design stage was described.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1728-1732
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• 2005

Gear trains are used in many machinery for variable speed ratios. Typical shapes of gear trains are two categories: simple gear trains and planetary gear trains. Generally the methods of the design typical shapes are two way. One of the methods is trailblazing design and the other is selective design in available types. This paper presents the mechanism types when input rotating velocity and output rotating velocity are maintained for useful planetary gear reducers of twelve types. Also, this paper gives the applicable example about rotating velocity of the gear axis, carrier velocity and the organized gear specifications

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.495-498
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• 2004

대전시 유성구 한국원자력연구소 부근 지역의 심부 단열대 확인을 위해 BHTV 검층, 일정구간별 정압 주입시험을 실시하였다. BHTV 조사 결과 A Zone(100m～120m)과 B Zone(250m～280m)이 연결되었다고 판단되며, 일정구간별 정압주입시험을 통해 B Zone(250m～280m)과 C Zone(400～420m)의 연결성을 추측할 수 있었다. 또한, 시추공의 심도별 지하수위 자료를 통해 지하 250m 부근에서 그 상부와 하부의 지하수 시스템이 연속되지 않은 독립된 시스템을 갖는다고 추측된다. 이러한 결론은 MP system이 설치된 시추공의 구간별 압력변화 결과에 의해서도 확인된다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.652-655
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• 2004

In gear-train design, power-flow analysis is a very important process. The method for power-flow analysis apply the power balance equation and torque balance equation to each fundamental circuit. Then, the equation are solved simultaneously to determine the power-flow in planetary gear train. In this paper we perform power-flow analysis of a 6-speed automatic transmission. With this results are used to represent block diagram. In addition, the efficiencies of epicyclic inversion of the 6-speed automatic transmission is obtained.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.3
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• pp.35-40
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• 1997

The traction drive has advantages of having high efficiency and transmitting the power without blacklash. However, when high ratio of speed reduction is desired, excessively large size is required. In this study, a new type of traction drive is invented, designed and manufactured so that stable speed reduction mech- anisms are available by adopting a cross roller type drive. It has a simple structure, but produces high speed reduction ratio. Power loss is observed, and also, driving torque and torque transfer efficiency are calculated. Pre-loads are needed in order that the traction drive transfers power without slipping, and the spacer is enlarged due to the pre-loading. After all, the key point of pre-load mechanism is that the spacer's diameter becomes larger as pre-loads are applied.

• 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.29 no.6
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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.

• Korean Journal of Plant Resources
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• v.1 no.1
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• pp.72-79
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• 1988

This experiment was conducted to breed the Boxthorn varieties with resistance to Anthracnose, good quality and high yielding potential in 1984 to 1986(3 years).The character of "Yu seong 1" with resistance to Anthracnose and "Yu seong 2"with good quality and high yielding potential are fellows;1, The plant type of "Yu seong 1" was semi-elect type but became to electtype after 60C" rediation and yield was decreased because of the number of flowers.2. The yield of "Yu seong 2" was the highest of all varieties.3. The quality(Extract and Betain contents) of "Yu seong 2" was the best ofall varieties and visible character was good.The results of this experinent showed that "Yu seong 1" should be promisinglines in south area because of resistance Anthracnose and "Yu seong 2" should bepromising lines in north area.hracnose and "Yu seong 2" should bepromising lines in north area.orth area.