• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.6
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• pp.452-457
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• 2016

Single screw compressors are widely used in the fields of air/gas compression, refrigeration, and chemical fluid transportation systems. A single-screw compressor is composed of a screw rotor and two gate rotors located at both sides. This simple construction enables low rotational speed of the rotor, efficient compression with low noise, low vibration, and long bearing life. Despite these merits, the design method of single-screw compressors is not well known. To accelerate the industrial application of single-screw compressors, a design method using coordinate transformation is presented in this paper, and a tool trajectory is established for machining. Finally, the screw rotor, which is machined using the proposed method, is presented.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.10a
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• pp.79-84
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• 1996

Recently a symmetric and non-symmetric profile of screw rotor has been designed in the interior. Howere the processing method of screw rotor and the cutter design for screw rotor were not studied. Therefor we could not make the shape of the screw rotor designed by profile function with computer. In this study we have made cutter profile design program and manufactured cutters for screw rotors using H.S.S We machined screw rotors of symmetric 4x6 profile non-sysmmetric 4x6 profile with almighty milling machine.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.907-912
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• 1994

Recently, a symmetric and non-symmetric profile of screw rotor has been designed in the interior. However the processing method of screw rotor and the cutter design for screw rotor were not studied. Therefore we could we could not make the shape of the screw rotor designed by profile function with computer. In this study, we have made cutter profile design program, and manufactured cutters for screw rotors using H.S.S. We have machined screw rotorts of symmetric 4*6 profile, non-symmetric 4*6 profile with almighty milling machine.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.2
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• pp.111-118
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• 2022

An electro-mechanical actuator (EMA) is an actuator that combines an electric motor with a mechanical power transmission elements, and it is suitable for urban air mobility (UAM) in terms of design freedom and maintenance. In this paper, the author presents the research results of the EMA that controls the rotor blade pitch angle of UAM. The actuator is based on an inverted roller screw and controls the blade pitch angle through a two-bar linkage. The dynamic equations for the actuator alone and the blade pitching motion with actuator were derived. For the latter, the equivalent moment of inertia is variable depending on the link angle due to the two-bar linkage. The variations of the equivalent moments of inertia are analyzed and compared in terms of the nut motion and the blade pitch motion. For an example model, the variation of the equivalent moment of inertia of the former is smaller than the latter, so it is judged that the dynamic equations derived from the point of view of the nut motion is suitable for the controller design.

• Polymer(Korea)
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• v.39 no.3
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• pp.441-452
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• 2015

Twin-screw kneader is an efficient polymer processing equipment. In this paper, the mixing performance of one novel intermeshing counter-rotating twin-screw kneader with different tip angles of the male rotor is simulated using the mesh superimposition technique (MST). Statistical analysis is carried out for the flow field using particle tracking technique, and distributive mixing performance is evaluated using the residence time distribution and segregation scale, while the dispersive mixing performance is estimated using the parameters such as shear rate, stretching rate and mixing index. The results show that the best distributive mixing performance is achieved when the tip angle is 0o, while the optimal dispersive mixing performance is obtained when the tip angle is 20o. The results in this paper provide a data basis for the selection of parameters and optimization of the performance for the screw rotors.

• The KSFM Journal of Fluid Machinery
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• v.16 no.1
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• pp.5-10
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• 2013

The performance of screw air compressor is affected by rotor profile, lobe number, air end wrap angle, rotor L/D ratio, suction and discharge ports, revolutions of air end and load regulation control, etc. In general, an efficient screw compressor needs a rotor profile of which has a large flow cross-section area, short sealing lines and a small blow-hole. In this study, experimental study was performed with newly designed $5{\times}6$ rotor profile and various shapes of air end. Results show that the measured specific power consumption of the newly designed screw compressor appeared to be lower than any other published data for the equivalent screw compressors manufactured.

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.139-142
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• 1999

Screw rotors are core parts of screw type air compressors, compressors in refrigerating machines and super chargers of automobiles etc. They are composed of a female and a male rotors which have complex section profiles and helically swept geometry. Screw type compressors have advantages of low noise, high efficiency, less needs in maintenance etc. Usually, machining process of screw rotors requires long machining time using CNC machine designed only for screw rotors, which increase the cost of production. In this work, the screw rotors for air-compressors were manufactured with fiber reinforced epoxy composite materials by resin transfer molding process. The mold for the RTM process was made of aluminum and silicon rubber and was designed for release of helical shape products. Composite screw rotors, manufactured by RTM process, have advantages of lightweight, less cost of production, good characteristics of vibration etc.