• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1995.03a
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• pp.41-53
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• 1995

Forging of spur gears has been investigated by means of upper-bound method. The term forging means forging of spur gears with solid cylindrical billets, hollow billets with flat punch. Kinematically admissbile velocity field for forging of spur gears has been proposed in this study. The 1/2 pitch of spur gear has been divided into seven dieformation regions, wherein, an involute curve has been introduced to represent the shape of die profile. Especially neutral surface has been introduced intor forging of hollow gears from hollow billets. By using the kinematically admissible velocity field, the powder requirements and suitable conditions for forging fo spur gears were successfully calculated with numerical method. According to the analysis , the acceptable number of teeth for forging of spur gears is from 15 to 20.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.347-348
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• 2006

Among various gear system, planetary gear system has the best characteristics in high efficiency, excellent strength capacity, easy convertible speed control, and compact design aspect. Strength of gear is considered as the most important design factor. We have studied tooth form and the planetary gear system that have high reduction gear ratio is created by using the involute curve.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1142-1147
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• 2004

The tooth profile of helical gear that is manufactured by the rack cutter consists of the involute curve and the trochoid curve. However, gear designers are very hard to calculate the exact profile because it needs very complex information about the gear manufacturing. Therefore, the purpose of this study is to develop the automatic generation program for the helical gear using the Solid Works API. First, involute and trochoide coordinates by the rack cutter are calculated. Using the data, Visual Basic program for the helical gear model is coded. This work gives us the quick helical gear modeling and can be used as the modeling for the finite element analysis.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1997.11a
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• pp.28-28
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• 1997

복합재료 부품을 설계할 때 필연적으로 한 부품이 두 가지 역할을 해야 하는 경우, 적용할 소재의 특성이 두 가지 필요조건을 만족하는 경우는 문제없으나 그렇지 않으면 단일 부품을 두 가지 소재로 설계/제조하여야 한다. 이때 계면의 강도를 최대로 할 수 있는 방법중의 하나가 involute construction 공정이며, 이 공정을 적용하는데 필요한 패턴설계와 적층 공정 및 두 소재사이의 계면 위치 등에 관하여 연구하였다. 계면의 형상을 톱니형으로 하기 위하여 패턴 설계는 1부품에 4가지 설계가 필요하고 적층 공정은 적층 치구를 이용하여야 한다. 계면의 위치는 적층 오차, 성형 중 수축 등을 고려하여 설계하여야 원하는 치수로 부품을 제작할 수 있다는 결론을 얻을 수 있었다. 적층 오차와 성형 중 수축에 의한 양을 분석하여 재 설계하였으며 그 결과 원하는 부분에 정확히 계면을 위치하게 할 수 있는 방법을 개발하였다. 2질 일체형 부품을 이러한 방법으로 제작하면 fabric prepreg를 이용하는 어떤 방법 보다도 정확한 부품을 제작할 수 있을 것으로 생각된다.

• Tribology and Lubricants
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• v.4 no.2
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• pp.28-35
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• 1988

A general and efficient algorithm is proposed for the analysis of the frictionless elastic contact problems. It utilizes a simplex-type algorithm with a modified entry rule and incoporates finite element method to obtain flexibility matrices. The algorithmic solution is compared with the Hertzian solution for the contact problem between two cylinders to prove its accuracy and the contact problem between pin and piston rod is solved and compared with the numerical results of Frankavilla and Zienkiewicz to demonstrate the generality and effectiveness of the suggested algorithm. The contact problem between mating involute gear teeth at the worst load position is considered. The computed contact stress is smaller than the result of Hertz's theory applied to the contact between two kinematically equivalent discs and the contact area is larger than that of Hertz's theory.

• Tribology and Lubricants
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• v.24 no.5
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• pp.221-227
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• 2008

This paper presents a step-by-step design of noncircular gears. From the diagram of angular velocity ratio of a noncircular gear pair, the pitch curves of the two mating gears are determined, and the perimeter of the pitch curve has been divided into equal-length segments by the number of teeth. A master tooth profile, which is a composite curve of circular arcs that represents involute, has been introduced. A noncircular gear pair has been designed by imposing the master tooth on the divided points of the pitch curve, and a full fillet has been achieved between neighbour teeth. Thus, the whole profile of the noncircular gear is a composite curve of arcs only, and consequently NC codes for wire EDM can be easily generated.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.12
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• pp.1237-1244
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• 2015

A gerotor can be manufactured in a miniature size because it has a high discharge per cycle and a simple structure. Gerotors are widely used for the lubrication oil of an engine and as the hydraulic source of an automatic transmission. Recently, improvements in fuel efficiency and noise reduction have come to the fore in the automobile industry, and it has been necessary for better fuel efficiency to continuously improve the flow rate and noise of internal gear pumps through the optimal design of the gerotor and port shape. In this study, gerotors were generated based on the equations derived for a lobe shape with multiple profiles (ellipse 1-elliptical involute-ellipse 2). The ranges of the design parameters were considered to prevent a cusp and loop. In addition, the optimal lobe shape was obtained by determining the influence of the lobe shape on the performances (flow rate, irregularity, etc.), according to the values of the design parameters.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.6
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• pp.631-637
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• 2013

The characteristics of involute gear pump with eccentric gap between gear tip and housing have been studied in terms of volumetric flow rate and/or flow efficiency. The analysis has been done with FLUENT/R-13 employing with k-e model for the turbulent flow under the given conditions of rotational velocity, gap distance and outlet pressure. The effect of parameters continues to be shown for the eccentric gear as same as for the concentric gear such that the volumetric flow rate (volumetric efficiency) increases as the increases of rotational velocity and decrease of gap distance and of outlet pressure. In the meantime, the shape of pressure build-up appears to be exponentially increase as gap distance decreases at upstream position. The pressure is rapidly developing in the upstream and remains almost constant thereafter in the downstream of circumferential flow path. This typical characteristics becomes more profound as eccentricity increases. The pump performance for the eccentric gear pump with minimum gap distance shows better than its concentric counterpart. However, it shows not for the concentric pump with minimum gap distance. Therefore, the gap reduction due to eccentricity may be positive for pump performance.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.1
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• pp.1-10
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• 1993

A design method of gear tooth profile which can reduce the noise of gear is studied. The tooth profile is generated by combining involute and cycloid tooth curves in which the involute tooth profile is near the pitch point and cycloid tooth profile at the addendum and the dedendum. Considering parameters which have an influence on the reduction of gear noise and building up a design conditions for the noise reduction of gear, the lower-noise combined gear tooth profile is designed. For the check of noise reduction of the combined gear profile, two pairs of combined profile gear, two pairs of involute gear, and a pair of cycloid gear were manufactured by the NC Wire Cutting Machine, and the experiment for measuring of gear noise was carried out on each pair. The noise reduction of the combined profile gear was obtained.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.9
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• pp.67-77
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• 2010

An internal lobe pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications. In particular, the pump is an essential machine element of an automotive engine to feed lubricant oil. The subject of this paper is the theoretical analysis of internal lobe pump whose the main components are the rotors: usually the outer one is characterized by lobe with elliptical and involute shapes, while the inner rotor profile is determined as conjugate to the other. And the integrated design system which is composed of three main modules has been developed through AutoLISP under AutoCAD circumstance plus CFD-ACE+. It generates new lobe profile and calculates automatically the flow rate and flow rate irregularity according to the lobe profile generated. CFD simulation results show trends similar to those carried out in experiments, and a quantitative comparison is presented. Results obtained from the automotive integrated design system enable the designer and manufacturer of oil pump to be more efficient in this field.