• Journal of the Korean Society for Nondestructive Testing
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• v.15 no.4
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• pp.520-530
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• 1996

In this study, the artificial defects in rotary compressor are classified using pattern recognition of acoustic emission signal. For this purpose the computer program is developed. The neural network classifier is compared with the statistical classifier such as the linear discriminant function classifier and empirical Bayesian classifier. It is concluded that the former is better. It is possible to acquire the recognition rate of above 99% by neural network classifier.

• Transactions of Materials Processing
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• v.7 no.5
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• pp.432-438
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• 1998

The process variables i.e. the speed of forming, the ratio of thickness to diameter the shape of formed materials and the reduction of area were selected in order to study the process of the rotary swaging. It was found that the process variables affected the quality of products, i.e. the hardness the surface roughness and the degree of precision of products. Variation of hardness in deformed samples was mainly dependent on the reduction of area. Upon forming tubes applying the t/D ration higher than 1/10 led to the formation of defects on products which may be reduced by application of mandrels.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.5
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• pp.491-502
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• 1997

This paper describes a theoretical and exprimental investigation of the pressure - time histories of some basic internal combustion engine exhaust systems. The program package is utilized the method of characteristics to solve the general equations of one - dimensional unsteady gas flow. This analysis is then combined with boundary models, based on quasi - steady flow approach, to give a complete treatment of the flow behavior in the exhaust system. Using a rotary valve exhaust simulator, experimental pressure - time histories were obtained. The predictions are com¬pared with measured results and show a high degree of correlation in amplitude and phasing.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.5
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• pp.20-26
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• 1997

A System for reducing vehicle body roll by active control is developed. The stabilizer bar with hydraulic rotary actuator produces anti-roll moment which suppresses roll tendency. This reduction of roll improves the driving safety as well as the ride comfort. Vehicle test data shows considerable reduction of roll angle during steady-state turning. Also improvement of ride comfort is achieved by making the actuator freely rotatable, i.e. by connecting all chambers of actuator in normal driving conditions. A control algorithm using steering wheel angle and vehicle speed signal as input valve is applied. It is compared with signal of the G-sensor.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.11
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• pp.160-166
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• 2002

In this paper, data acquisition and analysis of a measuring machine for marine engine's cams is discussed. A rotary encoder and linear scale of the machine to measure angular and linear displacement respectively are interfaced to the PC via encoder board with 2 channels. The design and measuring data are interpolated by cubic spline curves to compute the precision error which is defined by the maximum and minimum distances between two curves. The minimum zone fit of ISO is employed to evaluate the geometric deviation. The developed system takes only 5 minutes to measure and analyze while the CMM takes over 1 hours even with a skilled operator.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.6-9
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• 2005

In this study, the ultra precision centerless grinder for ferrule grinding was designed. As the good-qualified ferrule is required a precise and fine grinding, grinding machine for ferrule must have a high accuracy and a sufficient stiffness. The centerless grinder is composed of the high damping concrete bed, grinding wheel spindle unit, regulating wheel spindle unit, feeding table and dressing unit. For a newly developed centerless grinder, hydrostatic system with high precision feeding and high stiffness was proposed. The grinding and regulating wheel spindle units were composed of hydrostatic spindle and feeding table was hydrostatic table. The prototype of hydrostatic table was manufactured and tested.

• Tribology and Lubricants
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• v.12 no.4
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• pp.43-51
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• 1996

Rapid increase of refrigeration & air-conditioning system (r & a system) in modem industries brings attention to the urgency of research & development as a core technology in the area. And it is required to the compatibility problem of r & a system to alternative refrigerant for the protection of environment. Then, it is requested to study the lubrication characteristics of refrigerant compressor which is the core technology in the r & a system. The study of lubrication characteristics in the critical sliding component is essential for the design of refrigerant compressor. Therefore, theoretical investigation of the lubrication characteristics of rotary compressor for r & a system is studied. The Runge-Kutta method is used for the analysis of the behavior of rolling piston in the rotary compressor. The results show that the rotating speed of shaft and the discharge pressure have an important effect upon the angular velocity of the rolling piston. This results give important basic data for the further lubrication analysis and design of the rotary compressor.

• Transactions of Materials Processing
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• v.20 no.2
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• pp.93-98
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• 2011

Electroforming is a kind of metal molding technology. After gilding on the possession object(conductivity, nonconductivity) separate it with possession object and produce a part or duplicate. This process has an excellent ability of duplicating detailed figure. To simplify the manufacturing process of a rotary screen, this study was adopted electroforming technology and produced silicon rubber mandrel. Furthermore, to indicate the optimal condition for the acquisition of high-qualified rotary screen product, the experiment was executed with pH, time, sulfamate nickel solution according to density which were the main factors to decide the condition, then compared it with the product made by original "S" company in Holland. As a result, the figure of hole was more obvious and correct. Also the open size increased by more than 2-3%.

• Journal of Biosystems Engineering
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• v.26 no.3
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• pp.229-236
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• 2001

The torque loads acting on the input shaft of the transmission and final driving shaft of the tractor having a cage wheel attached to the driving tries as a traction aid were measured during the rotavating operations in a poorly drained paddy field. Using the measured load data load spectra were constructed. Effects of the design parameters of the cage wheel on the load characteristics were also analyzed. The torque load exerted on the input shaft decreased as the diameter of the cage wheel increased and increased as the rotavator speed increased. The torque load exerted on the final driving shaft increased as the working speed of the tractor increased and decreased as the rotavator speed increased. The torque load on the final driving shaft with the cage wheel were greater than those without the cage wheel.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.857-862
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• 2002

Compressor is a major noise source of air-conditioner. Especially, its low frequency band noise below 1000Hz is very important because it will not be attenuated by passing through the cover panel and heat exchanger in air-conditioner. The factors affecting the low frequency band noise are studied by geometric similarity along with several experiments, and the low frequency noise is closely related with the discharge holes of muffler as well as the cavity of lower shell. The low frequency band noise is significantly reduced by proposed designs.