• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.646-647
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• 2012

• Journal of Electrical Engineering and Technology
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• 제1권1호
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• pp.106-109
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• 2006

In this paper, the design and characteristics of a novel ultrasonic motor are investigated. Such a motor is appropriate far use in the optical zoom or auto focusing functions of the lens system in mobile phones. Its design and simulation of performances are carried out by FEM commercial software (ATILA). The shape of the motor is similar to a square without one side, on which an optical lens can be mounted. Two sheets of piezoelectric ceramics are adhered to both sides of two legs of the elastic body, respectively To drive the ultrasonic motor, the voltage is applied to two sheets of piezoelectric ceramics bonded to one leg. The rotation direction can be easily changed by switching the piezoelectric sheets bonded to the other leg, to which voltage is applied. A proto type of the motor is fabricated and its outer size is $10^*10^*2[mm3]$ including the camera lens of which the diameter is 7.5(mm). Its power consumption is about 0.3[W] and the speed of rotation is adjustable from 10 to 200[rpm] according to the applied voltage

• 한국정밀공학회지
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• 제30권11호
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• pp.1187-1192
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• 2013

In the case of 4 wheel drive (4-WD) type car, power switching occurs to 4-WD by operating lever or switch that operates power switching device attached in transfer case which can operate motor by electric signal. So if the RPM of motor is high, power switching will not exactly occur and can cause damage to gear in transfer case according to circumstances. So in this study, we applied 2 level of planet gear type motor spindle of motor drive part of a power train. And conducted decelerating to increase torque to switch power safe and accurately. Also, we researched efficiency of gear by designing reduction gear ratio and gear type and by calculating contact stress and bending strength. Based on researched content, we made drive head of power switching device and a reduction module which uses type that uses motor spindle as sun gear and ring gear as cover.

• 한국소음진동공학회논문집
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• 제15권4호
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• pp.499-505
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• 2005

In this paper, a new type of pi+ezoelectric stepping motor is designed, manufactured and tested. This motor is composed of piezoelectric torsional actuator and a pair of one-way clutch bearings. The torsional actuator consists of 16-polygonal tube of piezoceramic that can produce an angular displacement associated with shear mode. One-way clutch bearing converts oscillation of torsional actuator into a continuous stepping rotation. The proposed stepping motor does not require any conversion mechanism for stepping motion like any other motors. In the design process, the shear resonance mode of piezoelectric actuator is analyzed by using a commercial finite element analysis program, and the performance of the fabricated torsional actuator is measured. $0.124^{\circ}$ of maximum angular displacement is measured in square wave excitation on the actuator only. The stepping motor is manufactured by assembling a pair of one-way clutch bearings and the torsional actuator. The maximum rotation speed of 72rpm and the blocking torque of 3.136 mNm are measured at 3540 Hz and 100V/mm. Once the proposed piezoelectric stepping motor is miniaturized, it can be used for many compact and precise moving applications.

• 한국소음진동공학회논문집
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• 제22권7호
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• pp.642-649
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• 2012

This paper deals with a copper die casting induction motor which has several advantages of motor performance. The developed motor is used as spindle motor in machining center. The dynamic characteristic analysis of rotor is dealt with for precision machining. The critical speed of rotor considering rotation and gyroscopic effect should be above operating speed, 18,000 rpm, and have a 201 % sufficient separation margin. Also, the 3-D unbalance vibration response analysis is performed and enabled the prediction of the expected vibration amplitude by unbalance in high speed. The unbalance vibration responses of each position on the rotor are satisfied with allowable vibration displacement of API 611 standard according to balancing G grade(G 0.4, G 2.5, G 6.3). Copper die casting high speed induction motor is successfully developed and verified by experiment.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 춘계학술대회 논문집
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• pp.121-121
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• 2014

본 연구에서는 반도체 제조의 Diffusion 공정설비의 FFU (Fan Filter Unit) 진동에 의해 발생한 wafer 불량 현상을 규명 및 개선하였다. EFEM(Equipment Front End Module)의 Loading 부에 장착된 FOUP(Front Opening Unified Pod)에 들어 있는 Wafer 들이 설비 EFEM 하부로 떨어져 깨지거나 FOUP 내에서 겹침 현상이 발생하는 것을 확인하였다. 이에 생산현장의 모든 Diffusion 공정 설비를 조사하였으며, 그 결과 A 사(社)의 특정 설비에서만 발생되는 현상임을 확인하였다. 해당 A사(社)설비군에서만 월 평균 10 건의 Slot Mapping Error 가 발생하였으며, 이로 인해 Wafer가 재 제조된 매수가 월 평균 53 매로 확인되었다. 따라서 본 연구는 A 사(社)설비에서 발생하는 Mapping Error 의 원인 규명 및 개선을 위해 추진되었다. 총 12 개의 항목을 불량 발생 원인 후보 군으로 선정 후 예비 진단한 결과 FFU(Fan Filter Unit)에 의한 문제 발생 가능성이 가장 높을 것으로 추정되었다. 이에 따라 4 개의 서로 다른 물리적 환경/조건에서 진동을 측정하였으며, 최종 평가 결과 Motor 와 Blade 의 불균형에서 기인한 진동이 설비의 loader 부에 직접적으로 영향을 주는 것을 확인하였다. 진동 문제를 해결하기 위해 고 RPM blade 에서 저 RPM 및 유량 감소를 보완할 수 있는 신규모델로 교체하였다. 신규 Module(blade/motor) 장착 후 Load port 에서의 진동 측정 결과 개선 전 대비 91% 감소하였으며, 결과적으로 Slot mapping error 발생 건수가 50% 이상 감소되는 효과와 Wafer 재 제조 매수도 월 평균 약 43% 감소하는 효과를 얻을 수 있었다.

• 전력전자학회논문지
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• 제14권2호
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• pp.112-119
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• 2009

본 논문은 홀센서를 사용하는 고속 소형 BLDCM의 속도제어를 위해 PLL 방식을 적용하였다. 제안된 방식은 기준펄스 신호와 홀센서 신호와의 위상차를 이용하는 PLL 기반의 속도제어 기법으로, 별도의 속도 계산이 요구되지 않고, 지령전류는 직접 두 신호의 위상차에 의해 결정된다. 전류 지령은 두 펄스 신호의 위상차에 따라서, 전동기의 속도를 일정하게 유지하기 위하여 변화된다. 제안된 방식은 매우 간단하지만 효과적인 속도 제어를 구현할 수 있다. 또한, 부드러운 토크를 발생하기 위하여 지령 전류는 가속 및 감속 패턴을 따라 변동하도록 설계되었다. 제안된 방식은 50W, 40,000[rpm]급의 소형 고속 BLDCM에 적용하여 실험하였다.

• Tribology and Lubricants
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• 제10권1호
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• pp.14-26
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• 1994

The minimum oil film thickness(MOFT) in the connecting-rod bearing of a 1.5 liter, L-4, gasoline engine is measured up to 5500 rpm and calculated to study the dynamically loaded engine bearing. Short bearing approximation and Mobility method are used for theoretical analysis of oil film characteristics. And cylinder pressure, crank-pin surface temperature and bearing temperature are measured as the input data of theoretical analysis. The MOFT are measured by the total capacitance method(TCM). To improve the reliability of the test results, a reasonable determination method of bearing clearance is introduced and used, and the effects of cavitation and aeration on the test results are neglected. The crankshaft is grounded by means of a slip ring. A scissor type linkage system was developed to measure the MOFT and bearing temperature. The effects of engine speed, load and oil viscosity on the measured and calculated minimum oil film thicknesses are investigated at 1500 to 5500 rpm. From the comparison between the measured and calculated MOFT, it is found that a qualitative similarity exists between them, but in all cases, the measured MOFT are smaller than those calculated.

• 한국유체기계학회 논문집
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• 제18권3호
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• pp.33-37
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• 2015

A numerical study on the IPM/Bridge Diode cooling and coil cooling has been performed. Results are presented as plots of thermal resistance, temperature drop and RPM-ratio. CFD analysis for conventional cooling system has been performed as a reference case. As the RPM-Ratio was increased, heatsink thermal resistance and coil temperature were decreased. IPM/Bridge Diode thermal resistance and temperature of the coil is tended to be trade-off. The temperature of coil closest to the AC-motor fan showed the most significant change in accordance with duct design. The temperature of coil located at the top of DC-motor fan showed the most significant variation as the cooling air passes the heatsink fin area.

• 한국기계가공학회지
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• 제11권6호
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• pp.195-200
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• 2012

In this study, parameters and requirements of an 120kW class monorail planetary gearbox was analysed and the adaptive planetary gearbox design was selected. The specification of the sun gear, planetary gear and carrier was set and the profile & lead was optimized. The mechanical efficiency of the optimized one and the original one was observed. Dynamo-tester system was used to observe the mechanical efficiency of the planetary gearbox. A dynamo unit was connected with the planetary gearbox which straightened through the motor by a coupling. The standard tooth shape planetary gearbox and modified tooth shape planetary gearbox were used as test pieces and the rotation speed was set from 600 to 6000rpm with 600rpm, 2.5min one step. In order to check the mechanical efficiency of the planetary gearbox, the tests were done as follows. 1) The power loss between driving motor and dynamo tester. 2) Temperature variation by different rotation speeds. 3) Noise variation by different rotation speeds.