• Tribology and Lubricants
• /
• v.28 no.1
• /
• pp.27-32
• /
• 2012

Oval gears are typical kinds of non-circular gears and are widely used in flow meters. This paper presents a tooth profile design of an oval gear according to the curvature of the pitch curve. The length of the pitch oval is divided by the number of teeth and the curvature of the divided points is obtained. The tooth profile is designed on the circle of the curvature as if it is the pitch circle of a gear. The teeth of the oval gear have the same module and pressure angle, but the pitch circle of each tooth differs in size. Thus, the teeth on the divided points of the pitch oval are different in shape. This type of oval gear will improve the meshing properties.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.8
• /
• pp.1029-1033
• /
• 2013

Elliptical gear is used as a rotor of oval flowmeter. The elliptical gear can assist water flow-rate measurement by the space of the elliptical shape. Presently, elliptical gears have been processed using hob tool imported from Japan. But if it were not for the technical cooperation with Japan company, the Elliptical gears can't be processed. The purpose of this study is developing a domestic technology for elliptical gears and overcoming the dependence of foreign technical skills. It will bring the import substitution effect. In case of pressure angle $20^{\circ}$, the elliptical gears have an interference of tooth. The increase of pressure angle makes the root of a tooth thick and the top of tooth thin. By results of this study, tooth of elliptical gear was designed and verified through the 2D and 3D simulation.

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

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.9 no.1
• /
• pp.99-105
• /
• 2010

This study was performed to solve the breaking problem in the fine blanking(FB) process of sector gears for car seat recliner using nickel chrome molybdenum steel(SNCM220) plate. The optimal design of embossing circle is changed to oval with labors' experiences and finite element analysis. The maximum principal stress and effective strain in a forming process are analyzed by commercial finite element software to solve the problems in embossing stage of FB process. As a result of FE analysis, the maximum principal stress in forming is lower than yield point of material. It is shown from experiments in the modified die that the formed gear does not break in embossing stage.

• Korean Journal of Veterinary Research
• /
• v.23 no.1
• /
• pp.101-104
• /
• 1983

Authors encountered a case of elk babesiosis in Daegu, Korea. The main symptoms observed before the death of the patient were elevated rectal temperature, severe degree of hemoglobinuria, icterus and recumbency. Hematologically, the erythrocyte count was 1.93 million per cu.mm 11% of which were infected with Babesia. Most(88%) of the protozoa were spherical or vacuolated ring form in shape, resembling B. bovis. However, the sizes (0.98-2.85) were slightly smaller than the latter. About 7% of the protozoa were vacuolated oval, the size of which varied from $2.06{\sim}2.95{\times}1.08{\sim}1.97$ ($2.53{\times}1.51$ in average). The remaining 5% were irregular in shape. Pear-shaped were scarcely observed. A three-gears-old Korean native cattle was inoculated subcutaneously with the elk's blood. However, no evidence of susceptibility was observed until 30 days postinoculation.