• 한국기계가공학회지
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• 제10권4호
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• pp.22-30
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• 2011

This study analyzes harmonic vibration with natural frequency according to the configuration of damper clutch. In the case of double spring, equivalent stress at same direction of the revolution at inner and outer coil spring is over 30% as compared with at its opposite direction. Natural frequency or harmonic response with maximum deformation in case of the less coil pitch is below 3Hz as compared with in case of the more coil pitch. As the coil pitch of damper spring as the case 2 or 4 becomes smaller, its mass and deformation can be large. In these cases, spring constant and natural frequency become smaller. In the case 5 or 6 of double spring at natural vibration or harmonic response, the frequency becomes over 300Hz. As the result of this study is applied by the design of damper spring, the damage at its connected part is prevented and the durability can be predicted.

• 한국기계가공학회지
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• 제12권1호
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• pp.77-83
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• 2013

This paper presents the feasibility on the application of composite coil spring, which has great interest in the automobile industry. In order to obtain much lighter weight of the composite spring, it will be necessary to optimize the design variables such as fiber angles and diameter of coil, etc. First of all, mechanical properties were measured to consider the effects of FVR and ply angles for carbon fiber composite material. And the shear modulus with respect to ply angles were derived based on twisting angles calculated by torsional beam model. Next we determined the design parameters of composite coil spring, which has equivalent spring rate to the steel coil spring. In order to assess the proposed method, finite element model of the composite spring was developed and analysed to obtain the spring constant. The results showed that static spring rate of the composite spring was in a good agreement with that of steel spring.

• 대한안전경영과학회지
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• 제6권3호
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• pp.237-247
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• 2004

The condition of the manufacturing process in a factory should be diagnosed and maintained efficiently because any unexpected disorder in the process will be reason to decrease the efficiency of the overall system. However, if an expert experienced in this system leaves, there will be a problem for the efficient process diagnosis and maintenance, because disorder diagnosis within the process is normally dependent on the expert's experience. This paper suggests a process diagnosis using data mining based on the collected data from the coil-spring manufacturing process. The rules are generated for the relations between the attributes of the process and the output class of the product using a decision tree after selecting the effective attributes. Using the generated rules from decision tree, the condition of the current process is diagnosed and the possible maintenance actions are identified to correct any abnormal condition. Then, the appropriate maintenance action is recommended using the decision network.

• 한국기계가공학회지
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• 제6권3호
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• pp.85-91
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• 2007

This study was carried out to minimize the lifting force of a two hinge type stand mechanism. This unit is designed for the display devices in order to enhance the ergonomics for effective height adjustment and maintenance at any preferred position. The unit will be very useful for the mechanism fabricated with a coil spring and disc springs as a torque generator. The maximum and the minimum torque value should be calculated initially for the smooth lift. And the reasonable torque distribution is necessary to prevent any auto lift and auto dropping at any position because the torque generated by coil spring is more sensitive than disc spring in tilting the position. Therefore, the analysis of the coil spring is requisite to issue the specific torque value depending on the distorted angle with securing reliability of a long time storage condition. After the theoretical torque value was calculated, the evaluation was carried out by making a proto-type sample, then distorted angle was updated by experiment. The result of this study can readily be applied to various units for the optimization of the smooth lift.

• 한국생산제조학회지
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• 제22권1호
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• pp.131-137
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• 2013

Gas springs have been widely used in motor vehicles as well as in most areas of industry. Instead of coil springs, these gas springs are easily operated to extrusion process or compression process the doors because $N_2$ gas with high pressure and oil are charged in tube. Gas spring sustain the constant elasticity change rate in the high reaction force and long stroke, and they have compact design, appearance and an excellent assembling ability to be mounted easily with any applicatory products. By means of these aspects, gas springs have been widely used in stead of coil springs in the over all industries. In this study, using acommonly used program, ANSYS, the basic research about the heat transfer and equivalent stress change of bimetal.

• 한국기계가공학회지
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• 제9권3호
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• pp.8-18
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• 2010

A total stroke of an opening or closing motion of a hinge mechanism for a folder-type mobile phone is composed of two portions. In the first portion, human fingers act a torque to open or close the folder. In this portion, the rotating folder compresses the coil spring installed in the hinge mechanism. In the last portion, this compressed coil spring generates a torque to rotate the folder. In this study, we have developed an algorithm to design a hinge mechanism to be operated by an arbitrary continuous torque in the first portion of the total stroke. Consequently, we can design hinge mechanisms that satisfy various demands of consumers. A pair of contours installed in the mechanism plays an important role. It transforms the folder's rotational motion into translation to compress the coil spring in the first portion; on the other hand, it transforms translational motion into the folder's rotation in the last portion. Using this algorithm we have designed the pair of the contour curves operated by an arbitrary continuous torque.

• 소성∙가공
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• 제21권8호
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• pp.473-478
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• 2012

The yoke, a component of conventional motor-driven power steering system, often contains welding defects from its manufacturing process. To eliminate these defects, the precision cold forging process has been tried. In this study, the double-action complex forging has been used to manufacture a torsion joint yoke. The backward extrusion proved faster than the forward extrusion in forging of the product. The double-action complex forging process utilized an upper die composed of a punch, a punch guide, a disc spring and a coil spring. The forged material pushes up the punch guide, and then the disc spring and the coil spring balances the backward extrusion force. Consequently, the flow of material was essentially in the forward direction, resulting in a successful forging operation. The forging load of Al 6061-T6 was higher than that of the automotive structural hot rolled plate.

• 한국정밀공학회지
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• 제30권1호
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• pp.47-52
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• 2013

In order to operate a search and rescue robot in hazardous area, the robot requires high mobility and adaptable locomotion for moving in unpredictable environments. In this paper, we propose the deformable soft wheel robot that can produce three kinds of driving modes; caterpillar driving mode, normal wheel driving mode, legged-wheel driving mode. The robot changes its driving mode as it faces the various obstacles such as a small gap, stairs etc. Soft film and composite materials are used for fabrication of deformable wheel structure and Shape Memory Alloy (SMA) coil spring actuators are attached on the structure as an artificial muscle. Film lamination and an composite manufacturing process is introduced and the robot design is required to be modified and compromised to applying the manufacturing process. The prototype is developed and tested for verifying feasibility of the deformable wheel locomotion.

• 한국산업융합학회 논문집
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• 제9권1호
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• pp.51-59
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• 2006

The study is diagnosis about fatigue failure phenomenon of heating coil spring (sup9) and heat treatment method that is used to crusher. Because more than 80~90% of damage announcement of breakdown of machine and construction is been caused in fatigue present state, fatigue failure became important leading person at design. Calculated design load is imposed repeatedly that fatigue breakdown is safe. Is phenomenon that change load is imposed in the construction continuously. Used coil spring applies heat 30minute by Quenching temperature $860^{\circ}C$ if see manufacturing process and temperature of gasoline of $50^{\circ}C$ keep after quench that know tempering a $460^{\circ}C$ 90minute a product be. If doto apply heat $950^{\circ}C$ material at rolling process historically before quenching, austenite formation clay pipe being done AGS(Austenite Grain Size) by 2.5~4 become. Apply heat quenching 30minute by $820^{\circ}C$ by improvement method and after quench that keep $50^{\circ}C$ in oil tempering if do $450^{\circ}C$, 90minute spring ideal formation sorbite formation of the river form and condition that satisfy most more than AGS 7 appeared. Also, we can secure authoritativeness through MT since shot peening processing.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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• pp.960-968
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• 2005

The high cost in maintaining complex manufacturing process makes it necessary to enhance an efficient maintenance system. For the effective maintenance of manufacturing process, precise fault diagnosis should be performed and an appropriate maintenance action should be executed. This paper suggests an intelligent fault diagnosis system using hybrid data mining. In this system, the rules for the fault diagnosis are generated by hybrid decision tree/genetic algorithm and the most effective maintenance action is selected by decision network and AHP. To verify the proposed intelligent fault diagnosis system, we compared the accuracy of the hybrid decision tree/genetic algorithm with one of the general decision tree learning algorithm(C4.5) by data collected from a coil-spring manufacturing process.