• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.916-919
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• 2002

Cam mechanism is one of the common devices used in lots of automatic machinery. This paper introduces to an inverse cam mechanism. The inverse cam mechanism has a reverse structure as compared with common cam mechanism. For shape design of the inverse cam the approach used in this paper is an instant velocity center method that find the contact point between cam and roller at any contact time. And a computer program is developed for shape design and simulation by visual $C^{++}$ language. As the results, this paper presents two examples for the shape design of the inverse cam mechanism in order to prove the accuracy of the design procedures.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.411-415
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• 2002

In this paper, a mechanical probe for CMM (Coordinate Measuring Machine) with a three-axis force-sensing unit is proposed, which is capable of measuring an actual contact position without the lobbing effect and the pre-travel error. The force-sensing unit detects the external force, which is act on the stylus of CMM during the measuring process. Thus, the contact point of the stylus of CMM can be estimated ken the direction of measured force components. Based on the structural analysis of the proposed CMM probe, the transformation matrix is derived and calibrated so that it shows linear relationships between the estimated force components from the output voltages and the real input forces. And, the relationships are verified through the computer simulation. The results show that the proposed mechanical probe is very useful fur detecting the contacting force components on measuring process of CMM.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.4
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• pp.79-83
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• 2010

Recently, the flat wiper which is one piece wiper and subjected to a pressing force at a single center point is gaining wide applications on automotive windshields. However, nonuniform reactive pressure distributions takes place, so that wiping is not completed at such locations. The wiping performance of the flat wiper is best when a wiper and a curved windshield have perfect contact without gaps under the specified pressing force of 13 ~ 15 gf/cm. Therefore, it is necessary that the realistic curvature equation of a wiper spring-rail should be obtained. Finite element analysis, CATIA script-macro function, and the least square method were utilized to find out the curvature of a spring-rail for a perfect contact with a windshield under a specified concentrated load. The curvature equation became the third order polynomial.

• Proceedings of the KSR Conference
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• 2002.10b
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• pp.820-825
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• 2002

As the speed of rail transit is higher, it is very important to secure the safety and confidence of the braking device and in the point of view, by means of the rise of the temperature from the friction between the disk and pad which are the actual part of a braking system, the damage of brake disk is the main cause to lose the safety of braking device. Therefore, in this study, to predict the danger of a disk brake and to know its max. temperature in the train service the module of a temperature measurement by the non-contact method was developed.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.4
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• pp.153-160
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• 2001

In order to analyze the degradation process of epoxy/glass fiber for outdoor condition, FRP laminate was exposed to high temperature. Then, the degradation process was evaluated by comparing contact angle, surface potential, surface resistivity, and XPS. The experimental results showed that the amount of weight loss, contact angle, surface potential and surface resistivity increased up to 200 $^{\circ}C$ as a function of temperature. These phenomena show the existence of hydrophobic surface. With the change to the hydrophobic surface and the electrical potential and resistivity on FRP surface increased. In XPS to analyze surface chemical structures, the increased hydrophobicity in thermal increase of unsaturated double bond in carbon chains. Aslo, thermal treatment caused the discoloration on the point of treated surface. These phenomena were attributed to the generations of ether group.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.5
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• pp.85-95
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• 2001

This study proposed a technique for inverse problem, linear approximation of contact position and loading in single and double meshing of spiral bevel gear , using 2-dimension model considered near the tooth by root stress. Determine root stress is carried out far the gear tooth by finite element method and boundary element method. Boundary element discretization near contact point is carefully performed to keep high computational accuracy. And from those estimated results, the comparing estimate value with boundary element method value was discussed.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.523-528
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• 2003

AS City traffic means, the electric railway of the role is overwhelming with recognizing good merits of safety, no environment disruption and accurate destination time. Currently, Korea subway are running about 290km through eight subway lines. The latest constructed subway had been made by imperoved matherials which is going on improving. Therefore, we researched this project to keep up facilites easily, repress a leakge current and reduse install cost and repair time in changing facility at overhead Contact wire system because of arc by reforming construction plan about Expansion Joint and Air Section which is regarded as weak point when facilities are fixed and maintianed of Rigid Trolley bar System. as above we can contribute various part to making useful O.C.S(overhead contact wire system)

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.4
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• pp.159-164
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• 2003

In this paper, a three-dimensional finite element method and construction of equivalent-circuit for a linear ultrasonic motor are presented. The validity of three-dimensional finite element routine in this paper is experimentally confirmed by analyzing impedance of a piezoelectric transducer. Using this confirmed finite element routine, impedance and vibration mode of a linear ultrasonic motor are calculated. Elliptical motion of contact point between vibrator and rail of the linear ultrasonic motor is shown for determination of contact points. By using the finite element method and analytic equations, characteristics of the linear ultrasonic motor, such as thrust force, speed, losses, powers and efficiency, are calculated. The results are confirmed by experiment. Finally, equivalent circuit parameters of the linear ultrasonic motor are obtained using the three-dimensional finite element method and analytic equations.

• Textile Coloration and Finishing
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• v.29 no.2
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• pp.55-61
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• 2017

A non-fluorinated polystearyl methacrylate water repellent was synthesized by emulsion polymerization. The number and weight averaged molecular weights were obtained at around 137,277 and 237,754g/mole. The melting point was observed at $32^{\circ}C$. The contact angle of water droplet on fabrics treated with the water repellent was $140{\sim}145^{\circ}$ for cotton and polyester, and $125{\sim}130^{\circ}$ for wool and nylon. Since the critical surface tension was estimated at 20.7mN/m, even though relatively not so strong as fluorinated water repellent, it is considered to be used as a good water repellent practically.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.909-910
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• 2007

To design the Molded Case Circuit Breaker(MCCB) requires electromagnetic analysis in contact system when the circuit breakers interrupt fault currents. This paper has made sure that there are two ways increasing arc driving force, one is a change of contact point and the other way inserts additionally the magnetic plate. Finally, we have carried out the analysis of eddy current to identify a decrease of arc driving force because of fault currents. In this paper, MCCB models have been analyzed base on 3D-FEM by Maxwell program.