• Journal of the Korean Society for Precision Engineering
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• v.22 no.3 s.168
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• pp.21-28
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• 2005

In the hot forging process lubricant influences on frictional condition only, but in the warm forging process it influence on the formability such as dimensional accuracy, filling state and frictional condition and it is important to estimate a lubricating characteristic of lubricants in the warm forging. In this paper, in order to evaluate the formability of billet in warm forging process according to the lubricant and lubricating method, lubricant and lubricating test have been performed using oil-based and water-based lubricant which were widely used in the hot and warm forging processes. The surface roughness of initial billet was measured to evaluate the influence on the formability of billet and the forming load and dimensional accuracy were compared and evaluated. From the experimental results, it can be known that water-based lubricants are more excellent than oil-based lubricants for warm forging of complex shape like a bevel gear. Also, in this study characteristics of deformation have been investigated according to surface treatment of initial billet.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.2 no.1
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• pp.1-6
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• 2001

This study is concerned with the cold forging of sintered preform by rotary forging process and direct powder compacting process. An experiment has been carried out using the rotary powder forging press (500kN) which had been designed and equipped with the rotational conical die inclined to the central axis of the press at certain angle The effect of process variables was observed and measured by several mechanical test, such as hardness distribution density, and microstructure of the specimens. It is found that the highly densified P/M parts can be obtained and this process is very effective for improving quality of the powder products.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1997.10a
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• pp.22-23
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• 1997

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1999.04a
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• pp.539-540
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• 1999

• Journal of the Korean Society for Precision Engineering
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• v.9 no.4
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• pp.78-89
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• 1992

The most important criteria of quality of meshing and contact of gears are the low level of noise and the sufficient dimensions and location of the contact. A new approach for determination of machine-tool settings for spiral bevel gears is proposed. The proposed settings provide a function of transmission errors, the desired location and orientation of contact. The function is able to absorb piece-wise linear functions of transmission errors that are caused by the gear misalignment and to reduce the gear noise. The determination of pinion machine-tool settings is based on the local synthesis of gears. A computer program for simulation of meshing bearing contact and determination of transmission errors for misaligned has been developed.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.730-733
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• 2001

A computer aided design system for spur, helical, bevel and worm gears by using AutoCAD system and its AutoLISP computer language was newly developed in this study. Two methods are available for a designer to draw a gear. The first method needs the gear design parameters such as pressure, module, number of tooth, shaft angle, velocity, materials, etc. When the gear design parameters are inputted, a gear is drawn in AutoCAD system and maximum allowable power and shaft diameter are calculated additionally. The second method calculates all dimensions and gear design parameters to draw a gear when the information such as transmission, reduction ratio, rpm, materials and pressure are inputted. The system includes four programs. Each program is composed of a data input module, a database module, a strength calculation module, a drawing module, a text module and a drawing edit module. In conclusion, the CAD system would be widely used in companies to find the geometric data and manufacturing course.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.6
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• pp.99-103
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• 2014

A hypoid gear is a type of spiral bevel gear whose axis does not intersect with the axis of the meshing gear. The size of a hypoid gear is compact and the ratio of contact is high; therefore, the noise is lower than in other types. Due to these characteristics, the hypoid gear is commonly used in manufacturing processes such as those of escalators and subway screen doors. The purpose of this paper is to develop a reducer using the hypoid gear. In order to check the stability of the proposed reducer, 3D modeling is carried out by CATIA, and a structural analysis is performed using FEM (a finite element method).

• Journal of the Korean Society for Precision Engineering
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• v.20 no.7
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• pp.185-192
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• 2003

This paper proposes an efficient mechanism design system of multi-stage gear drives including not only parallel shaft gears but also non-parallel gears such as bevel and worm gear drives. The system automatically generates three dimensional structures of specification-adjusted mechanisms, and shows the sorted list of the mechanisms according to the evaluation result by using a fuzzy expert system. The list can be used as reliable candidates of the spatial mechanism structures of multi-stage gear drives. Thus, it is expected that the system can increase the efficiency of design and cut off the expenses of preliminary design considerably.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.139-142
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• 2009

As important mechanical elements, gears have been used widely in power transferring systems such as automobile transmission and there have been several researches trying to make gear parts with cold or warm forging in order to reduce cost and time required to gear manufacturing process. Although forging processes of spur and bevel gears have been developed as practical level owing to active previous researches in Korea, the manufacturing of helical gear has been still depended on traditional gear cutting processes such as hobbing, deburring and shaving. In order to manufacture helical gears with cold forging process, a research project supported by government has been conducted by Daegu university, KIMS and TAK and this paper deals with effects of back pressure forming technique to cold forging of helical gear as a fundamental research.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.184-187
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• 2005

Forging process is one of the forming process and is used widely in automobile parts and manufacture industry. Especially the gears like spur gear, helical gear, bevel gear were produced by machine tool, but recently they have been manufactured by forging process. The goal of this study is to study forming process with data obtained by comparison between forward extrusion and upsetting simulation results and formability improvement by various heat treatment conditions. By analysis data of 3D FEM by upsetting and forward extrusion forming, the forming process of clutch gear develops using data based on 3D FEM analysis. Through tensile test using specimens by various heat treatment conditions, the optimal heat treatment condition is obtained by comparison the results of tensile test.