• Journal of the Korean Society for Precision Engineering
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• v.33 no.2
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• pp.109-114
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• 2016

Nowadays, lower gear vibration and noise are necessary for drivers in automotive gearbox, which means that transmission gearbox should be optimized to avoid noise annoyance and fatigue before quantity production. Transmission error (T.E.) is the excitation factor that affects the noise level known as gear whine, and is also the dominant source of noise in the gear transmission system. In this paper, the research background, the definition of T.E. and gear micro-modification were firstly presented, and then different transmission errors of loaded torques for the spur gear pair were studied and compared by a commercial software. It was determined that the optimum gear micro-modification could be applied to optimize the transmission error of the loaded gear pair. In the future, a transmission test rig which is introduced in this paper is about to be used to study the T.E. after gear micro-geometry modification. And finally, the optimized modification can be verified by B&K testing equipment in the semi-anechoic room later.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.6 s.183
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• pp.44-51
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• 2006

This paper deals with the aspects of die design for the multistage fine tooth hub gear in the cold forging process. In order to manufacture the cold forged product for the precision hub gear used as the ARD 370 system of bicycle, it examines the influences of different designs on the metal flow through experiments and FE-simulation. To find the combination of design parameters which minimize the damage value, the low gear length, upper gear length and inner diameter as design parameters are considered. An orthogonal fraction factorial experiment is employed to study the influence of each parameter on the objective function or characteristics. The optimal punch shape of fine tooth hub gear is designed using the results of FE-simulation and the artificial neural network. To verify the optimal punch shape, the experiments of the cold forging of the hub gear are executed.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.3
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• pp.207-216
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• 2016

A gerotor is suitable for miniature manufacturing because it has high discharge per 1 cycle and a simple structure, while also being widely used for lubrication oil of engines and as a hydraulic source of automatic transmission. In the automobile industry, improvements in fuel efficiency and noise reduction have recently come to the fore. It has also been necessary to continuously improve the flow rate and noise of internal gear pumps for better fuel efficiency through optimal gerotor and port shape design. In this study, to develop an optimal gerotor with a new lobe shape, 2-ellipses-combined, the equation of the lobe shape was derived, and CFD analysis results were compared for 2-ellipses with those of the previous gerotors (3-ellipses and ellipse1-involuteellipse2). A performance test for the oil pump with the optimal rotor (2-ellipses) was carried out and showed good agreement with the results obtained from CFD analysis.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.929-932
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• 2011

We developed a valve actuator controller for thruster system. This thruster system has four actuators and the actuator use a BLDC motor. Controller was made based on system and control requirement. The controller is consist of power, control and Amp. The control module use a micro-controller which is TMS320F28335 of Texas Instruments. It works for digital PID control and CAN communication and system control. The amp module for three phase BLDC motor use IGBT.

• Environmental and Resource Economics Review
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• v.7 no.1
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• pp.165-183
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• 1997

생명공학은 기술의 특성상 보건 의료, 농업, 자원 환경, 에너지 등 광범위한 산업에 응용될 수 있는 고부가가치형, 두뇌기술집약형, 탈공해형, 자원 및 에너지절약형 기술이라는 특징을 지니고 있어 21세기 미래산업을 선도할 것으로 기대되고 있다. 본 연구의 목적은 생명공학기술이 1980년과 1990년 사이의 산업구조에 어떠한 변화를 초래하였는지를 알아보는 것이다. 생명공학의 산업경제적 파급효과를 분석해 보기 위해 한국은행에서 발행한 산업연관표를 이용하여 생명공학 관련산업의 지원에 따른 국내 제반산업의 생산변화율을 측정하였다. 정부의 지원이나 금리 및 세제의 혜택을 통해 생명공학 산업 관련 비용이 감소하게 되면 이에 따른 가격변화가 국내 산업발전과 고용의 증가를 갖는 것으로 믿어진다. 고정계수 아닌 변화계수를 특징으로 하는 본 모형의 접근방법은 생명공학에 대한 재정지원 및 세제 인센티브 등을 외생변수로 처리하여 산업구조 변화의 추이와 고용유발 등을 예측하였다. 본 논문의 가설은 생명공학의 영역이 점차 증대되어 나아가기 때문에 1980년의 제반산업의 영향은 1990년의 영향보다는 적어야 한다. 즉 생명공학 관련비용 하락이 전체산업에 미치는 1980년의 생산율 증가보다 1990년의 생산율 증가가 커야 할 것이다. 본 가설에 대한 검증의 과정에서 얻은 통계치를 통해 생명공학산업이 한국 산업 전체에 미치는 영향이 10년 동안에 그 차이가 거의 없어 미성숙 단계에 있다는 결론을 짓게 되었다. 따라서 생명공학 분야의 계속적인 발전을 위해서는 선진국 수준의 독자적 기술개발을 통한 국제 경쟁력을 강화해야 하는데 이를 위한 정부 및 민간기업 투자확대와 연구개발 지원체제의 확대가 요망되고 있다.

• Proceedings of the KAIS Fall Conference
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• 2011.12b
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• pp.417-420
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• 2011

본 논문에서는 자전거의 구동 및 변속 창치인 스프라켓에 관한 연구이다. FEM을 이용하여 티타늄 소재 스프라켓의 구조해석을 수행하기 위해 10단 Cassette를 설계하였고, 사용자가 가장 많이 사용하는 단수인 4, 5, 6단을 티타늄 소재로 선정하였다. 티타늄 재료의 물성치를 실험을 통해 확보하였으며, 이를 이용하여 티타늄 스프라켓의 각 치형에 걸리는 Equivalent Stress를 구하였고 스프라켓 고정장치인 스파이더와의 체결 후의 Equivalent Stress를 구하여 티타늄 스프라켓의 안정성을 확보한다.

• Tribology and Lubricants
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• v.36 no.2
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• pp.64-67
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• 2020

In the conventional gerotor design, the circular arc tooth of the outer rotor is first introduced, and then the inner rotor profile is generated by simulating the outer rotor motion while the inner rotor is fixed. The profile generation of tooth meshing exhibits relativity; therefore, the outer rotor profile can be generated by the movement of the inner rotor. In this study, we propose the design of a gerotor with a pin-tooth inner rotor. First, the pin-tooth inner rotor is devised, and then the outer rotor profile is generated. The profile of the inner rotor is simply composed of equally arranged pins along a circle. The root of the inner rotor is designed as a conjugated arc of two pins. The trajectory of the pin center is obtained by the inner rotor operation, and then the outer rotor profile is determined as a parallel curve of the trajectory. In this gerotor design, the inner rotor has a simple configuration, and contact occurs between the pin parts of the inner rotor and the whole profile of the outer rotor. This affects the material selection and machining process. The pin tooth can be used to design the outer and inner rotors, enabling a double gerotor mechanism corresponding to a planetary gear system.

• Journal of Digital Convergence
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• v.15 no.10
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• pp.445-454
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• 2017

Recently, playing musical instruments in the application or website which is a sort of playing has been catching on for ordinary people even though they don't know how to play musical instruments. It appears that such playing has randomness which is quite natural. Thus, 'Random operation method' which induces the observing audience and changes them to manage actively is developed and suggested for the image system in this paper by utilizing Launch Pad, based on theoretical background and case analysis. Step Sequencer was developed in two ways: the image system is realized with Step Sequencer by connecting external program or made as clips to arrange them for each key on Launch Pad and implement, which is keyboard launch type.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.5
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• pp.85-92
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• 1998

This present paper describes a mathematical model of profile shifted elliptical gears, and this model is based on the concepts of envelope theory and conjugate geometry between the blank and the straight-sided rack cutter. The geometric model of the rack cutter includes working regions generating involute curves and fillets for trocoidal curves, and furthermore the addendum modified coeff. is considered for avoiding undercutting. The addendum modified coeff. is changed linearly along with pitch curves and must be the same absolute value at both major semi-axis and minor semi-axis. If undercutting is at all pronounced, the undercut tooth not only are weakened in strength, but lose a small portion of the involute adjacent to the base circle, then this loss of involute may cause a serious reduction in the length of contact. A very effective method of avoiding undercutting is to use the so-called profile shifted gearing. Non-undercutting condition is examined with the change of eccentricity and addendum modified coeff. in elliptical gears and then the minimum number of tooth is proposed not to gernerate undercutting phenomenon.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.1
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• pp.19-25
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• 2007

Among the precision reduction gent drivers lot robot system, the cycloid reducer is well known for it's high performances. Designing this reducer, there are many factors which must be considered. First, a geometrical analysis of tooth shape must be drawn from the basic concept. Second, loads, stresses and modification factors on tooth should be calculated exactly. Finally, a computer software to optimize the design of cycloid tooth needs developing on the basis of the geometric and force equations. In this research, the expert system to design the cycloid reducer was developed using Visual C++ so, the most important factors can be obtained automatically as the user put the simple input data.