• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.87.1-87
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• 2003

• Electrical & Electronic Materials
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• v.10 no.7
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• pp.727-731
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• 1997

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.495-496
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• 2010

• Tribology and Lubricants
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• v.27 no.5
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• pp.249-255
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• 2011

Recently the demand for a fast and precise actuator in semiconductor industries is growing larger. A SAW motor is now expected as a new friction-drive actuator to meet such demand. However, its friction and wear properties are almost unknown and its low stability and reliability still remain to be solved. In this research the tests of SAW motor were carried out and its durability was discussed. The effect of wear caused by friction on the driving force and driving speed were clarified.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.864-866
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• 2012

이동로봇은 동작 특성상 다수의 하드웨어로 구성되기 때문에 분산제어 방식으로 동작하는 것이 필수적이므로 네트워크 기반의 인터페이스 설계가 중요하다. 다양한 네트워크 중 전장에서 산업현장에 이르기까지 여러 분야에 적용중인 CAN 버스 통신을 적용하여 이동로봇을 구성하는 각 하드웨어의 독립성과 장애물 판단, 모터 구동 등을 정확하게 제어함으로써 자율주행에 따른 이동로봇의 성능을 향상시키고 하드웨어 추가에도 대응이 가능하도록 설계하였다.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.267-268
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• 2016

기존 EV용 모터구동 Boost Converter의 경우, 모터 기동 시 필요한 순간적인 큰 전류를 배터리에서 공급하기 때문에 배터리의 수명이 감소되는 문제점이 있다. 이를 해결하기 위해 출력 단에 Super Cap. String을 사용하여 순간적으로 필요한 큰 전류를 공급하였다. 하지만 Super Cap. String은 높은 전압을 견뎌야 하기 때문에 회로의 전체적인 부피가 커지고 원가를 증가시키는 문제점이 있다. 본 논문에서는 낮은 내압의 Super Cap. String을 사용 할 수 있는 Modified Boost Converter를 제안한다. 제안 회로는 Super Cap. String을 사용하여 배터리의 효율을 극대화 시킬 수 있으며, Super Cap. String의 직렬 연결 개수 감소로 회로의 소형화 및 원가 저감이 가능하다. 본 논문에서는 제안된 회로의 이론적 특성을 분석하고 모의실험을 통해 제안회로의 우수성을 검증하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.1 s.173
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• pp.269-274
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• 2000

Frictions and electrical contact voltages of the herringbone-grooved hydrodynamic bearing(HHB) were 9, measured to use in a laser scanner motor. This bearing with varying loads, speeds, oil viscosity, and radial clearances successfully operated up to 28,000rpm and 0.5N. Experimental results under various environments confirmed that this bearing had excellent performance with low friction force, and operated without contact between shaft and sleeve.

• The KSFM Journal of Fluid Machinery
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• v.1 no.1 s.1
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• pp.32-40
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• 1998

Aerodynamic performance of a cooling fan of driving motor was enhanced modifying the vane-shroud configuration. Performance of a target model was evaluated to obtain baseline data. The aerodynamic performance and sound pressure level were tested and measured with different numbers of vane of increased length. The tested models show high and stable performance and low values of specific noise level. The long vane-shroud structure induces more stable through flow and decreases the tip leakage flow, which contributes to the increases of performance and efficiency. The sound pressure level increases for the modified model, however, specific noise level decreases.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.439-444
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• 2004

The important problem in high speed spindle is to reduce and minimize the thermal effect by motor and ball bearings. In this study. the effects of bearing preload and cooling for high speed spindle with high frequency motor are investigated. A high speed spindle is composed of angular contact ball bearings, high frequency motor, grease lubrication, oil jacket cooling, and so on. Heat generation of the bearing and the high frequency motor are estimated from the theoretical and experimental data. The thermal analyses of high speed spindle to minimize the thermal effect and maximize the cooling effect are carried out under the various cooling conditions and preload. Method of variable bearing preload and cooling can be useful to design the high speed motor spindle. The results show that the optimal preload and cooling are very effective to minimize the thermal displacement by motor and ball bearing.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.5
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• pp.29-34
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• 2014

Cooling the in-wheel motor in electric vehicles is critical to its performance and durability. In this study, thermal flow analysis was conducted by evaluating the thermal performance of two conventional cooling models for in-wheel motors under the continuous rating base speed condition. For conventional model #1, in which cooling oil was stagnant in the lower end of the motor, the maximum temperature of the coil was $221.7^{\circ}C$; for conventional model #2, in which cooling oil was circulated through the exit and entrance of the housing and jig, the maximum temperature of the coil was $155.4^{\circ}C$. Therefore, both models proved unsuitable for in-wheel motors since the motor control specifications limited the maximum temperature to $150^{\circ}C$.