• 한국기계가공학회지
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• 제12권6호
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• pp.142-151
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• 2013

This study develops an automation system for metallic mold design that is applicable in forging non-axial symmetric parts. The metallic mold design program is used to design the metallic mold using two-dimensional axial symmetric metallic molds and to predict the stress concentration using finite element analyses. Then, the program redesigns the metallic mold using variables such as the optimal split diameter, maximum allowable inner pressure, fit tolerance, and stress distribution, which are calculated using the metallic mold design program. When the involute spur gear is forged, stress concentration occurs on the tooth root bounded at the symmetric surface. The SCM4 material is suitable for metallic molds because the stress is less than the yield strength of the insert and it acts on the tooth root regardless of the inner pressure. The metallic mold for forging non-axial symmetric parts can be designed through adjusting the magnitude of the contact pressure. The program developed in this study can be applied to metallic mold designs in involute spur gears of forging, which is an ordinary non-axial symmetric part.

• 호남수학학술지
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• 제27권2호
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• pp.267-271
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• 2005

We study hypersurfaces in the Euclidean space with the following property: the tangential part of the position vector has constant length. As a result, we prove that among the connected and complete hypersurfaces in the Euclidean space, only the hypersphere centered at the origin satisfies the property.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.1227-1228
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• 2010

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.1209-1210
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• 2010

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 추계학술대회 논문집
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• pp.263-264
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• 2009

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 춘계학술대회 논문집
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• pp.541-542
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• 2007

• Imaging Science in Dentistry
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• 제45권2호
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• pp.123-131
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• 2015

Throughout the years, various classifications have evolved for the diagnosis of vascular anomalies. However, it remains difficult to classify a number of such lesions. Because all hemangiomas were previously considered to involute, if a lesion with imaging and clinical characteristics of hemangioma does not involute, then there is no subclass in which to classify such a lesion, as reported in one of our cases. The recent classification proposed by the International Society for the Study of Vascular Anomalies (ISSVA, 2014) has solved this problem by including non-involuting and partially involuting hemangioma in the classification. We present here five cases of vascular anomalies and discuss their diagnosis in accordance with the ISSVA (2014) classification. A non-involuting lesion should not always be diagnosed as a vascular malformation. A non-involuting lesion can be either a hemangioma or a vascular malformation depending upon its clinicopathologic and imaging characteristics.

• Tribology and Lubricants
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• 제30권4호
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• pp.212-217
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• 2014

A counter gear transmits the rotation angle, so the angular velocity ratio of the gear does not necessarily need to be constant in the meshing process. As a pinion has a small number of teeth when combined with an internal gear for counters, tooth interference can occur with the use of an involute curve. This paper introduces circular arcs that represent a tooth profile and fillet for the profile design of a pinion through the combination of arcs with lines. The straight line of a rack tooth represents the profile of a mating internal gear. Thus, the circular arc and line maintain contact during the rotation of the counter gear. This paper presents an analysis of the meshing of the circular arc tooth and rack tooth along with the properties of the counter gear, such as the change in rotational velocity and amount of backlash. The contact ratio of the counter gear is 1 because the tooth contact occurs between circular arcs and line. The initial position of tooth contact, which denotes the simultaneous contact of two teeth, is found. As the rotation of the pinion, only one tooth keeps the contact situation. This meshing property is analyzed by the geometrical constraints of the tooth profile in contact and the results are presented as graphical diagrams in which tooth-arc movements are superimposed.

• 한국지능시스템학회논문지
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• 제16권3호
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• pp.315-320
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• 2006

산업 현장에서는 많은 종류의 감속기들이 사용되고 있다. 그 중 로봇에서는 사이클로이드(cycloid) 치형 혹은 인벌루트(involute) 치형을 가진 고정밀도의 감속기를 사용한다. 그 이유는 로봇 시스템에서는 위치 제어를 하는데 있어서 고정밀의 감속기를 사용하는 것이 필수적이기 때문이다. 본 논문에서는 기본적으로는 삼각형 치형을 가지고 있지만 새로운 직선치형을 갖는 로봇 감속기(RSR)를 제안한다. 제안한 감속기는 유한요소 해석법을 이용한 강도, 응력, 강성 테스트에서 좋은 결과를 얻을 수 있었으며, 편심계수를 변화시켜 최적의 치형 운동을 얻을 수 있도록 설계하여 응력이 적게 걸리고 소음을 낮출 수 있도록 하였다.

• 한국정밀공학회지
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• 제28권5호
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• pp.614-622
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• 2011

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 multiple profile(ellipse1, involute and ellipse2) shapes, while the inner rotor profile is determined as conjugate to the other. Also, the design of outer rotor depends on new applications with removing carryover phenomenon. The system generates new lobe profile and calculates automatically the flow rate and flow rate irregularity according to the lobe profile generated. In order to obtain rotor shapes in performance and to find optimize the design parameters, a Taguchi method is proposed in this paper. Results obtained from the analysis enable the designer and manufacturer of oil pump to be more efficient in this field.