• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.317-322
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• 1994

The design and performance verification of collocated capacitance sensor system for magnetic bearing is presented. Noncollocation between actuators and sensors may cause unstable rotor behavior. The capacitance sensor is not affected by magnetic field. PCB type capacitance sensor is installed between magnetic bearing polse. so, collocation of sensors and actuators can be achieved. Experiment of sensor's static and dynamic charactistics is conducted. Modeling of the rotor system supported by magnetic bearing is made. And performance comparison between simulation and experiment is showed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04a
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• pp.615-619
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• 1995

The unbalance response analysis is one of the essential area in the forced vibration analysis of rotor-bearing systems. Local bearing parameters in ortor-bearing systems are the major sources which give rise to a difficulty in unbalance response computation due to the complicated dynamic properties such as rotational speed dependency and anisotropy. In the present paper, an exact condensation procedure is introduced to easily take into account bearing parameters in computation of unbalance responses for rotor bearing systems. The present method is illustrated through a numerical example and compared with the conventional method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.105-106
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• 2011

• Journal of the Korean Society for Precision Engineering
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• v.33 no.4
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• pp.257-264
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• 2016

Solid state joining techniques are increasingly applied in a wide range of industrial applications. Friction welding is a solid state welding technique that is used to join similar or dissimilar materials. In this study, friction welding was applied to rotor shaft composed of a disk and a shaft. The disk and shaft were manufactured by hot forging and rolling, respectively. The aim of the study was to predict the structural characteristics during hot forging and friction welding process for rotor shaft of turbo charger. The structural characteristics were determined by heat input and heat affected zone (HAZ) during a short cycle time. Thus, transient FE analysis for hot forging and friction welding was based on heat transfer. The results were used to predict structural characteristics during hot forging and friction welding processes. The prototype of rotor shaft was manufactured by the result-based process parameters.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.9
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• pp.1003-1011
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• 2012

A new type of gerotor developed in this paper has the inner rotor designed by inserting a polycircular-arc between the hypocycloid and epicycloid curves, and we also suggest that the outer rotor be designed using the closed-form equation for the inner rotor and a method of modification. Thus, it is possible to design a gerotor for which there is no cusp and loop, as in this case undercut is prevented. We developed automated program for rotor design and calculation of the flow rate and flow rate irregularity. And we also demonstrate the superior performance of the gerotor developed in this study by analyzing the internal fluid flow using a commercial computation fluid dynamics-code (CFD).

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.7
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• pp.891-896
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• 2010

A gerotor is used in power-steering units (PSUs) as well as in hydraulic motors or pumps. The inner rotor is developed on the basis of the shape of the outer rotor tooth, which normally has one arc. The method of generating inner rotor on the basis of a generalized shape of outer rotor is analyzed with a view to improve PSU characteristics. An arc-shaped outer rotor with two curvatures was used in the analysis; design parameters such as the shape and curvature of the inner rotor, the flow rate of the gerotor, the position of contact point, and slip velocity are calculated, and these results are shown. This analysis enables us to develop a new design of compact PSUs.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.759-760
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• 2012

• Journal of the Korean Society for Precision Engineering
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• v.32 no.8
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• pp.713-718
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• 2015

This article describes the calculation procedure for the dynamic characteristics of a high-pressure labyrinth seal wherein the friction force and rotor whirling force are considered; SFCP, the commercial code developed by Lee and two colleagues, is used in the procedure. The simulation results were reviewed in comparison to those of the experiments provided by Benckert; additionally, the SFCP simulation results were verified using the CFD analysis presented by Toshio Hirano. This calculation procedure may therefore be applied to the dynamic characteristics of the labyrinth seals of high-pressure turbo machinery.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.5
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• pp.22-33
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• 1997

This paper describes a research work of developing a computer-aided design of blanking and piercing for stator and rotor parts. Based on knowledge-based rules, the die design system, STRTDES2, is designed by considering several factors, such as complexities of blank geometry and punch profile, and availability of press equipment and standard parts. Therefore this system can carry out a die design for each process which is obtained from the result of an automated process planning system, STRTDES1 and generate part drawing and the assembly drawing of die set in graphic forms. Knowledges for die layout are extracted from plasticity theories, relevant references and empirical know-hows of experts in blanking industries.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.672-675
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• 1997

This paper presents the identification of rotor dynamic parameters. The solution of the system equation can be obtained using least square method. The sensitivity analysis is performed to extract optimized solution, which is considered to be insensitive to inherent measurement errors. The cosine and sine term of orbit shapes can be obtained by experiment the orbit analysis at a different speed after doing orbit analysis at an arbitrary selected speed. This values measured time domain used to search the stiffness and damping coefficients of rotor bearing.