• Journal of the Korean Society for Precision Engineering
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• v.23 no.9 s.186
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• pp.54-60
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• 2006

Fitting process carried out in automobile transmission assembly line is classified into three classes; heat fitting, press fitting, and their combined fitting. Heat fitting is a method that heats gear to a suitable range under the tempering temperature and squeezes it toward the outer diameter of shaft. Its stress depends on the yield strength of gear. Press fitting is a method that generally squeezes gear toward that of shaft at room temperature by press. Another method heats warmly gear and safely squeezes it toward that of shaft. Warm shrink fitting process for automobile transmission part is now gradually increased, but the parts (shaft/gear) assembled by this process produced dimensional changes of gear profile in both radial and circumferential directions. So that it may cause noise and vibration between gears. In order to solve these problems, we need an analysis of warm shrink fitting process, in which design parameters are involved; contact pressure according to fitting interference between outer diameter of shaft and inner diameter of gear, fitting temperature, and profile tolerance of gear. In this study, an closed form equation to predict contact pressure and fitting load was proposed in order to develop optimization technique of warm shrink fitting process and verified its reliability through the experimental results measured in the field and FEM, that is, thermal-structural coupled field analysis. Actual loads measured in the field have a good agreement with the results obtained by theoretical and finite element analysis and also the expanded amounts of the gear profile in both radial and circumferential directions are within the limit tolerances used in the field.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.5 s.182
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• pp.37-43
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• 2006

Fitting process carried out in automobile transmission assembly line is classified into three classes; heat fitting, press fitting, and their combined fitting. Heat fitting is a method that heats gear to a suitable range under the tempering temperature and squeezes it toward the outer diameter of shaft. Its stress depends on the yield strength of gear. Press fitting is a method that generally squeezes gear toward that of shaft at room temperature by press. Another method heats warmly gear and safely squeezes it toward that of shaft. Warm shrink fitting process for automobile transmission part is now gradually increased, but the parts (shaft/gear) assembled by this process produced dimensional change in both outer diameter and profile of the gear. So that it may cause noise and vibration between gears. In order to solve these problems, we need an analysis of warm shrink fitting process, in which design parameters are involved; contact pressure according to fitting interference between outer diameter of shaft and inner diameter of gear, fitting temperature, and profile tolerance of gear. In this study, an closed form equation to predict contact pressure and fitting load was proposed in order to develop optimization technique of warm shrink fitting process and verified its reliability through the experimental results measured in the field and FEM, that is, thermal-structural coupled field analysis. Actual loads measured in the field have a good agreement with the results obtained by theoretical and finite element analysis and also the expanded amounts of the outer diameters of the gears have a good agreement with results.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.6
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• pp.47-54
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• 2008

Fitting process carried out in the automobile transmission assembly line is classified into three classes; heat fitting, press fitting, and their combined fitting. Heat fitting is a method that heats gear to a suitable range under the tempering temperature and squeezes it toward the outer diameter of shaft. Its stress depends on the yield strength of gear. Press fitting is a method that generally squeezes gear toward that of shaft at room temperature by a press. Another method heats warmly gear and safely squeezes it toward that of shaft. Warm shrink fitting process for the automobile transmission part is now gradually increased, but the parts (shaft/gear) assembled by this process produced dimensional changes in both the outer diameter and profile of the gear. So that it may cause noise and vibration between gears. In order to solve these problems, we need an analysis of warm shrink fitting process, in which design parameters are involved; contact pressure according to fitting interference between outer diameter of shaft and inner diameter of gear, fitting temperature, and profile tolerance of gear. In this study, an closed form equation to predict contact pressure and fitting load was proposed in order to develop an optimization technique of the warm shrink fitting process and verified its reliability through the experimental results measured in the field and FEM, that is, thermal-structural coupled field analysis. Actual loads measured in the field was in good agreements with the results obtained by the theoretical and finite element analysis.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.30.2-34
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• 1999

The hydroforming technology has gained in importance over the last few years, because of its potential for substantial weight avings costs reduction and quality improvement such as collision property, shape fixability and rigidity of white body. However, in comparison with the traditional sheet forming process, the hydroforming is much younger and the main development efforts were made in the last 15 years. The new technology, high pressure tublar hydroforming in particular, involves many process parameters to be optimized. This paper covers a brief overview of the hydroforming simulator as well as design of die and tools. The effects of typical parameters such as internal pressure and axial compression stroke are presented. Moreover, the conditions of forming failure occurrences such as fracture and wrinkle are examinated.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1810-1815
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• 2003

Tube hydroforming provides a number of advantages over conventional stamping process, including fewer secondary operation, weight reduction, assembly simplification, adaptability to forming of complex structural components and improved structural strength and stiffness. In this study, the effect of the heat treatment on the hydro-formability has been investigated. By using the mild steel tube bulging test is performed at various heat treatment conditions to evaluate the hydro-formability.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.3
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• pp.259-268
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• 2015

An optimization method for the tube hydroforming process is developed using the equivalent static loads method for non linear static response structural optimization (ESLSO). The aims of the tube hydroforming optimization are to determine the axial forces (axial feedings) and the internal pressures, and to obtain the desired shape without failures after hydroforming analysis. Therefore, the magnitude of the forces should be design variables in the optimization process. Also, some tube hydroforming optimization needs to consider the result of the thickness in nonlinear dynamic analysis as responses. However, the external forces are considered as constants and the thickness is not a response in the linear response optimization process of the original ESLSO. Thus, a new ESLSO process is proposed to overcome the difficulties and some examples are solved to validate the proposed method.