• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.11
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• pp.1453-1459
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• 2011

A roller pinion gear (RPG) system composed of either a pin or a roller and its conjugated cam gear can improve the gear endurance from that of a conventional gear system by reducing the sliding contact while increasing the rolling motion. In this paper, we first proposed the exact cam gear profile and the self-intersection condition obtained when the profile shift coefficient is introduced. Then, we investigated the Hertzian contact stresses and the load stress factors while the varying the shape design parameters to predict the gear surface fatigue life, which is strongly related to the gear noise and vibration at the contact patch. The results show that the pitting life can be extended significantly by increasing the profile shift coefficient.

• Journal of Aerospace System Engineering
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• v.17 no.6
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• pp.27-34
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• 2023

This paper presents the application of a magnetic gear to the electric propulsion system for an aircraft. Since high torque is required in aircraft electric propulsion systems, combining a speed reducer can amplify the torque. However, mechanical gears have issues, such as friction, vibration, and heat generation, which lead to maintenance challenges. In the case of a direct-drive motor that does not use mechanical gears, the size and weight of the motor increase to achieve high torque. This paper proposes the application of a magnetic gear to solve the maintenance issues of mechanical gears and the weight increase problem of direct-drive motors in aircraft electric propulsion systems. In this paper, a magnetic gear suitable for aircraft electric propulsion systems is designed, and it is compared with a direct-drive motor in terms of performance and the feasibility of applying the magnetic gear is verified.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2223-2228
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• 2014

Available shafts with gears at each end of the cylinder-shaped steel are widely used as power train components for automobiles. In order to automate the production of a geared shaft, there are problems to be solved. After one side of the cylinder is cut in gears, one of the problems is to determine the position of the cylinder which has been already cut. The shaft is then to be fed ahead with geared position to the chuck with jaws in geared shape. The other problem is to acquire information on an angular position of the shaft to fit to the jaws of the chuck. This paper deals with the magnetic detection sensor of gear position. Coils are installed in two places. Self-inductances of coils are detected by the changes of reluctance and are then compared. The magnetic analysis also has been carried out by the finite element analysis (FEM).

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.398-403
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• 2000

The design of multi-stage gear drives is a time-consuming process that includes additional design problems, which are not considered in the design of single-stage gear drives. In the previous research works, the authors have proposed a new algorithm to design multi-stage gear drives at the preliminary design phase. The proposed design algorithm automates the design process by integrating the dimensional design and the configuration design process. In the configuration design process, the positions of gears and shafts are determined by minimizing the geometrical volume (size) of a gearbox. However, various types of spatial constraints should be satisfied in practical design situation. To locate input and output shaft in specified positions is the typical example of such problems. In this paper, the authors show the formulations of spatial constraints applied to the design of four-stage gear drives. The design solution shows considerably good results, and the design system is confirmed to be readily applicable to practical design situation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.1
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• pp.59-63
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• 2014

Elliptical gears are used in the oval flowmeter and oval flow meter inspects volume of water thanks to space by the elliptical shape. The purpose of this study is to judge accuracy of processing of the elliptical gear and develop inspection system using machine vision. Demand of machine vision is increasing while the factory automation is spreading and principle factor in-process inspection. But, gear inspection using the machine vision rarely used because of complex shape of gear. In this study, it seems possible that elliptical gear is inspected by inspection software using machine vision and inspection program can judge accuracy of processing of the elliptical gear designed this study.

• Proceedings of the KAIS Fall Conference
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• 2011.05b
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• pp.824-827
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• 2011

본 논문에서는 자동차 시트 리클라이너 기어의 파인 블랭킹 성형 실험을 통하여 V-링 설치 위치에 따른 기어의 다이 롤 높이 변화를 검토하였다. 3 종류의 다이 편과 가이드 플레이트 편을 설계하여 파인 블랭킹 금형을 제작하였으며 650 ton 파인블랭킹 프레스에서 성형 실험을 수행하였다. 실험으로부터 제품을 취출하여 다이 롤 높이를 측정하여 분석한 결과 기어 모듈과 관계없이 V-링 설치 위치가 가이드 플레이트에서 멀어짐에 따라 다이 롤 높이가 증가함을 파악할 수 있었다. 이와 같은 결과는 향후 파인 블랭킹 금형의 V-링을 설계할 때 다이 롤 높이를 최소화하기 위하여 유용하게 활용될 수 있을 것이다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.104-109
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• 2018

Generally, the durability of the parking lock gear is evaluated through an endurance test for the entire transmission but no test standard exists for the durability test of one part of a parking lock gear. Therefore, in this study, the durability test standards of the parking lock gear were determined autonomously, and the durability performance test was conducted. A static fracture test was carried out to determine the yield strength of the parking lock gear, and a durability test condition was set to 60 % of the yield strength. The durability test of 1,000,000 times was conducted under the given conditions using a dedicated test jig manufactured for the test. Because the jig fractured during the static fracture test, finite element analysis for the jig was carried out and the jig was re-designed. The modified jig was manufactured and the durability test was carried out based on the test standard of autonomously. The basic data on the performance and endurance limit of the parking lock gear were obtained using these tests and analyses, and the basic data will be used as fundamental materials for the design and the development of the parking lock gear.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.880-881
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• 2015

최근 풍력발전의 산업이 성장함에 따라 풍력 발전기의 부속품에 대한 연구도 활발해지고 있다. 이에 본 논문에서는 풍력 발전기의 기계적 증속기의 문제점을 개선한 비접촉식 자기 기어를 제안하고 기어비에 따른 기어의 특성을 분석하였다. 각 모델들의 전체 크기 및 자석 사용량은 동일하게 고정하였으며 기어비에 따른 극수 및 회전수만을 조절하여 도출된 결과값을 바탕으로 풍력발전기용 증속기 설계 시 기어비 결정에 대한 지표를 제시하고자 한다.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.5
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• pp.1023-1028
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• 2018

Mechanical gears driven by direct contact have problems including noise, vibration and heat. In order to, solve these problems, magnetic gears having a non-contact magnetic coupling have been proposed. Through various studies on magnetic gears, we found that losses are changed when the number of magnetic poles varies in the same gear ratio. For this reason, research team expect the iron loss of the magnetic gear and the Eddy current loss of the permanent magnet will have a certain tendency depending on the number of poles. This paper identified the magnetic gear's loss tendency according to the number of poles, and laid the basis for efficiency improvement design.

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.181-188
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• 2015

The non-contact permanent magnet gear has advantages of high efficiency and improved reliability. It has other advantages of no mechanical friction loss, very little noise and vibration, and no need for lubricant. With these advantages, the non-contact permanent magnet gear that solves the physical contact problem of the mechanical gear has drawn attention. Due to this unique non-contact characteristic, the non-contact permanent magnet gear which is capable of non-contact torque transmission has replaced mechanical gear. The mechanical gears which is in many fields of the modern industry, is used mostly for power transmitting mechanical devices. However, it also has the problem of a low torque density, which requires improvement. In this paper, a novel pole piece shape is proposed in order to improve the problem of low torque density of the non-contact permanent magnet gear. The experiment data required for predicting the relationships among them are obtained using finiteelement Operating method based on two-dimensional (2-D) numerical analysis. Therefore, this paper derived an optimal model for thenon-contact permanent magnet gear with the novel pole piece using the Box-Behnken design, and the validity of the optimal design of the proposed pole piece shape through variance analysis and regression analysis demonstrated. In this paper, we performed the thransfer torque analysis in order to improve the torque density and power density, we have performed on optimal design of proposed pole piece shape using box-behnken.