• 한국산학기술학회논문지
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• 제14권2호
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• pp.548-553
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• 2013

Electro-Hydraulic Power Steering(EHPS) 시스템은 오일펌프에 직결된 전기모터를 통해 조향 조작력을 발생시키는 시스템이다. 이러한 스티어링 시스템 부품의 원가 및 성능을 최적화시키는 것은 매우 중요하다. 현재까지 EHPS 시스템과 같은 유압시스템의 개발은 실차 실험을 통해 문제점을 보완하여 개발하고 있기 때문에 많은 시간과 비용이 발생한다. 본 논문에서는 EHPS용 개발한 외접형 기어펌프의 토출유량측정실험을 수행하고 실험 데이터를 통하여 토출유량을 계산할 수 있는 유량 근사식을 제안하였다. 제안한 유량 근사식의 검증을 위해 실험데이터 및 AMESim 유량값과 비교하였고, 그 결과 각각의 유량특성간 오차율 5%내외로 유사성을 입증하였다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.177-182
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• 2002

In the paper, the development of high-speed industrial turbo blowers with foil air bearings is presented as a first successful commercialization in the world. Their target market is various from wastewater treatment to cement factory processes which require compressed air ranging between 0.6 and 0.8 bar gauge. Employing the state-of·the-art technology of the high-speed BLDC motors, the bump-type foil air bearings and the high- efficient turbo impellers/diffusers, so much compact, efficient and silent blower machines of a single stage are now available in the market, aiming to replace the existing inefficient, bulky and noisy ones, such as roots blowers. The first production lines are established fur 25,75 and 150 hp class blowers. Rotational speeds from about 20,000 to 80,000 rpm are realized directly from the high-speed BLDC motors without any gear boxes, and no lubrication oil is required. A brief introduction of design, manufacture and test results is presented fur mechanical, electrical and aerodynamic performance.

• 한국산학기술학회논문지
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• 제13권3호
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• pp.1008-1013
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• 2012

EHPS는 탈엔진형 조향기술로 BLDC 모터를 통해 유압펌프를 작동시켜 조향력을 보조하는 동력 조향장치이다. EHPS는 BLDC 모터, 기어펌프 및 유압회로, 파워 스티어링 등으로 이루어진 전기전자, 유압 및 기계시스템의 복합적 시스템으로 모델링이 어렵다. 본 논문에서는 EHPS 시스템의 구성 부품을 수학적 모델링 하였고, AMESim을 이용하여 multi-domain 시스템의 시뮬레이션 모델을 구축하였다. 이를 활용한 다양한 시뮬레이션을 통해 개발 초기단계에서의 시행착오를 줄이고 완성도 높은 EHPS 개발 업무를 수행하는 데 도움을 줄 수 있을 것으로 사료된다.

• Journal of Biosystems Engineering
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• 제43권1호
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• pp.1-13
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• 2018

Purpose: The development of compact tractors that can be used in dry fields, greenhouses, and orchards for pest control, weeding, transportation, and harvesting is necessary. The development and performance evaluation of power transmission units are very important when it comes to tractor development. This study evaluates the performance of a driving power transmission unit of a 50 kW multi-purpose narrow tractor. Methods: The performance of the transmission and forward-reverse clutch, which are the main components of the driving power transmission unit of multi-purpose narrow tractors, was evaluated herein. The transmission performance was evaluated in terms of power transmission efficiency, noise, and axle load, while the forward-reverse clutch performance was evaluated in terms of durability. The transmission's power transmission efficiency accounts for the measurement of transmission losses, which occur in the transmission's gear, bearing, and oil seal. The motor's power was input in the transmission's input shaft. The rotational speed and torque were measured in the final output shaft. The noise was measured at each speed level after installing a microphone on the left, right, and upper sides. The axle load test was performed through a continuous equilibrium load test, in which a constant load was continuously applied. The forward-reverse clutch performance was calculated using the engine torque to axle torque ratio with the assembled engine and transmission. Results: The loss of power in the transmission efficiency test of the driving power unit was 6.0-9.7 kW based on all gear steps. This loss of horsepower was equal to 11-18% of the input power (52 kW). The transmission efficiency of the driving power unit was 81.5-89.0%. The noise of the driving power unit was 50-57 dB at 800 rpm, 70-77 dB at 1600 rpm, and 76-83 dB at 2400 rpm. The axle load test verified that the input torque and axle revolutions were constant. The results of the forward-reverse clutch performance test revealed that hydraulic pressure and torque changes were stably maintained when moving forward or backward, and its operation met the hydraulic design standards. Conclusions: When comprehensively examined, these research results were similar to the main driving power transmission systems from USA and Japan in terms of performance. Based on these results, tractor prototypes are expected to be created and supplied to farmhouses after going through sufficient in-situ adaptability tests.