• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1517-1520
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• 2003

In this paper, we design a wedge type rail-clamp which can protect container crane from wind with constant clamping force regardless of the operating period. When we design wedge type rail clamp, it is important to determine the weight for locker to descent smoothly with an initial clamping force of rail and pad. Therefor, this paper suggest a process to decide a wright within proper range which could be obtained using FEA of wedge type rail clamp.

• Tribology and Lubricants
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• v.23 no.2
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• pp.61-65
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• 2007

It is very important to connect machinery and maintain it. This is usually done by bolt joint. There are two ways in connecting the bolt joint : the angle method and the torque method. The torque method is a method that let the clamping force maintain. The underhead of the bolt's head and the thread friction are the main influences. This study focuses on how the clamping farce and friction coefficient change under the condition in vibrating the underhead of the bolt's head part. As a result, under vibration condition, we found out that the clamping farce increases, while the friction coefficient decreases.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04b
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• pp.175-178
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• 2004

The microstructure, electrical, and clamping voltage characteristics of ZPCCD-based varistors were investigated at sintering time of 2 and 3 h. The average grain size and density of varistor were increased from 15.2 to 19.0 and from 5.5 to 5.6 $g/cm^3$ with sintering time, respectively. The nonlinear exponent was 65.4 for 2 h and 37.4 for 3 h, and leakage current was 0.54 ${\mu}A$ for 2 h and 0.67 ${\mu}A$ for 3 h. The dissipation factor was 0.0397 for 2 h and 0.0457 for 3 h. The clamping voltage ratio at surge current($8/20{\mu}s$) of 10~300 A was increased in the range of 1.56~2.17.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.843-848
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• 2000

In general, inchworm actuators are composed of two clamping piezoelectric elements and one expansion piezoelectric element. In this paper, two electromagnetic clampers are used for higher speed and high load. Dynamic equation is derived to simulate the behavior of the inchworm actuator with electromagnets. Electromagnetic clamper is used to improve the performance of the inchworm actuator. The electromagnetic clamper is composed of two permanent magnets and one traditional electromagnet. The permanent magnets play the role of the source of magnetic field to make clamping force higher, and the electromagnet is to change the mode between clamping and free. The driving voltage profile is also analyzed to improve the speed of inchworm actuator. The real system was manufactured and experimented to find dynamic characteristics and the maximum speed is obtained. Dynamic model is verified by comparing with experimental results.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.3
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• pp.26-35
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• 1997

In this study, the drawing characteristics of circular drawbead are examined with the plane strain elastic-plastic FE Method. Both the clamping load and the drawing load investigated by varying the process variables such as drawbead radius, closing depth and friction condition. The effective strain induced by the draw bead is also investigated. In order to verify the results, the computed results are compared with the existing experimental results. It has been found that both the clamping load and drawing loads are related with the geometry of the bead rather than the lubrication conditions.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.6
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• pp.745-750
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• 2011

A jig vise is a device to clamp workpiece precisely, which is widely used for various machine tools and manufacturing purpose. A new elastic structured jaw-wedge of jig vise is developed, in this paper, so as to satisfy the clamping requirement and the suppression effect of upright movement of workpiece. The advanced design parameters of jaw-wedge are derived step by step considering the stress distribution and the displacement profiles of ANSYS analysis, and it could find the optimum model which shows the uniform displacement profiles and exhibits the non-concentrated stress distribution of jaw neck. As a result, it is ascertained that an jaw-wedge developed in this study is the simple elastic structure which is effective for automatic multiple clamping purpose without the danger of shear crack or bucking of jaw.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.144-149
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• 1996

In this paper, the clamping type forging of helical gears has been investigated. Clamping type forging is an operation in which the product is constrained to extrude sideways through an orifice in the container wall. Punch is cylindrical shaped. The punch compresses a cylindrical billet placed in a die insert. As a consequence the material flows in a direction perpendicular to that of punch movement. The forging has been analysed by using the upper-bound method. A kinematically admissible velocity field has been developed, wherein, an involute curve has been introduced to represent tooth profile of the gear. Numerical calculations have been carried out to investigate the effects of various parameters, such as module, number of teeth, helix angle, friction factor and initial height of billet on the forging of helical gears.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.337-341
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• 2002

In these day, micro systems have gained attention with development of advance technologies. Researches about the fabrication of micro parts are actively made in the whole world. Among the researches, technology for micro injection molding machine is one of the key issues for fabrication of micro parts. In this study, we developed a micro injection molding machine for micro parts. To achieve this, injection unit was constructed using a screw with diameter of 12 mm. Clamping unit with clamping force of 1.75 kgf/$\textrm{cm}^2$ was constructed. Also verification test fur fabrication of micro parts was performed. It was performed that the micro injection molding machine can fabricate micro parts based on the result.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.279-281
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• 1996

This paper deals with the two stage surge protection device by using varistor and LC low pass filter. Recently varistor alone has been used with overvoltage protection devices for the AC power mains and has same problems associated with high remnant voltage and noise. In this work, in order to improve the cutoff performance of surge protection device, the lightning surge protection device having two stage hybrid circuit for an AC single phase mains was designed and fabricated. Operation characteristics and surge clamping performance of the surge protection device in an $8/20{\mu}s$ surge current are investigated. As a consequence, it is found that the proposed two stage surge protective device for AC power mains has a variety of advantages such as a smaller clamping voltage, high frequency noise reduction and large clamping capacity.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.12
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• pp.1611-1618
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• 2018

This paper proposes a new auxiliary resonant commutated pole (ARCP) inverter which has a modified auxiliary circuit. The proposed auxiliary circuit includes two auxiliary IGBT switches, an LC resonant circuit, and two clamping diodes. In order to analyze the performance of proposed ARCP inverter, computer simulations with PSCAD, and hardware experiments were carried out. Through analyzing the experimental results, it is known that the proposed ARCP inverter offers efficiency improvement of 1.5% compared with the hard-switching inverter.