• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1996.10a
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• pp.174-184
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• 1996

Two methods for cold extrusion processes to produce an axisymmetric steel gear blank are investigated for comparing each other. The "classical" forming method consisting of four operations is selected first to be simulated using the rigid-plastic finite element method and uses single-die presses. The other using a fully automated transfer headers can produce the final part without interannealing. The final products must be checked at the design criteria such as area reduction, the extrusion ratio and punch diameter to depth ratio, especially punch buckling by simulations. FEM analysis is performed mainly for strain distribution, both process sequences are proved to have proper charicteristics suitable for each production method in terms of maximum load. Those simulation results will provide good design criteria in the future work to advance the manufacturing process.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.12
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• pp.3227-3235
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• 1994

This paper deals with an evaluation of the residual stress due to shot peening induced in a carburized gear tooth and its application to the fatigue crack propagation problem. A practical method is proposed on the basis of the assumption that the residual stress is caused by the difference of volume expansion in the case and the core, and the influence of both the reduction of retained austenite and the strain due to shot peening are considered. The evaluated residual stress is close to the measured stress, though the surface stress is rather overestimated. The stress intensity factor is computed by the influence function method, and it is shown that the factor is decreased by the residual stress in shot peened gear tooth. The shot peening is fairly effective to the reduction of fatigue crack growth rate. The crack propagation is simulated and the resistance due to shot peening is quantitatively demonstrated and discussed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.323-326
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• 2004

In these days, gear whine noise of the axle and transmission is getting more important for reduction of vehicle noise, because major noise of vehicle was reduced. Therefore, in this paper, axle noise and vibration is measured, and then the modal analysis and running modal analysis is applied for reduction of axle gear whine noise.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.1
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• pp.80-86
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• 2008

In this study. the noise sources were identified and the noise and vibration were reduced for an industrial forklift. To identify the noise sourses, noise signals were measured by a microphone on a driver seat and these signals were analyzed with a waterfall plot. For this purpose, the gear mesh frequencies from the gear box of a reducer were not only investigated but noise/vibration sourses of an electric motor were also examined. Furthermore, the frequency response functions were obtained to confirm the vibration and noise sourses. It was found that severe vibration and noise were generated in the casing and the connecting part of the reducer. The severe vibration and noise could be reduced by a structure modification.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2006.11a
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• pp.21-24
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• 2006

• International Journal of Automotive Technology
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• v.7 no.4
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• pp.477-483
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• 2006

A vibration model of a helical gear pair for vehicle transmission is developed by considering the elastic deformation of the active teeth and the body to be a rigid. The main source of vibration in a helical gear system which caused by the mass unbalances of rotors and the transmission errors of gearings in mathematically formulated and applied to the analysis of vibration characteristics of geared systems. As an example, a simple geared system containing a helical gearing is considered. The critical speeds are found by the Campbell diagram and compared with the experimental results We expect this developed program to contribute to the reduction of the vibration and noise on vehicle a transmission in the field of both design and manufacturing. In addition, this program can be used as a basic program for CAD/CAM of low-noised gear teeth.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.34-38
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• 2003

In metal working, cold forging that has profit to satisfy dimension accuracy is using in various manufacturing products. Recently, most of the interest thing is precision forging of gear. Gear forging product is more strength than broaching gear, and it has many advantages with reduction of factory expenses. The reason of difficulty to improve accuracy of gear dimension compare to another products is the dimension accuracy is very high, approximately 10$\mu\textrm{m}$, and because die of involute teeth and elastic strain of forged tool differ from standard curve. This paper represent quantitative analysis of die and teeth of forged tool, namely difference of curves, with experiments and analyze the factor of dimension gap, finally, will design compensated involute curve.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.4
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• pp.762-767
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• 1998

The main torsional vibration source of the powertrain is the fluctuation of engine torque. The gear rattle is impact generating in the backlash of the free gear due to this torsional vibration. Optimization of the clutch torsional characteristic is one of the effective method to reduce the idle gear rattle. Many researches have been reported on this problem but only few of them give sufficient consideration to the detailed clutch modeling and the experiment. This paper pays attention to the optimization of clutch design parameters and the experiment to reduce the idle gear rattle vibration and noise.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.697-701
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• 2007

In this paper, noise sources of a planocentric gear reducer are identified by experimental mehod. This study consider a reduction method of a noise/vibration about the gear, axle, bearing and others. Namely, the purpose of this study is to reduce a noise/vibration for a stability of the total system. Form the data to be measured through an experimental method, the problems of the gear, axle, bearing and others are examined closely, and the reducer is derived the model to be the engineering. The mechanism of the problem occurrence is examined through a parametric research about an each influence factor(Load). Lastly, the results of this study propose the model to be improved.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.224-231
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• 2006

A six-degree-of-freedom dynamic model with time-varying mesh stiffness/damping and friction has been developed for the dynamic analysis of a gear driving system. This model includes a spur gear pair, bearing, friction and prime mover. Using Newton???s method, equations of motion for the gear driving system were derived. Two computer programs are developed to calculate mesh stiffness, transmission error and friction force and analyze the dynamics of the modeled system using a time integration method. The influences of mesh stiffness/damping, bearing, and friction affecting the system were investigated by performing eigenvalue analysis and time response analysis. It is found that the reduction of the maximum peak magnitude by friction is decided according to designing the positions of pitch point and maximum peak in the responses.