• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.5
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• pp.489-495
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• 2016

This study focuses on a detailed ball-bearing model for spur gears. The nonlinear ball-bearing stiffness with radial clearance is derived and calculated. The bearing stiffness is used to the 3-degree-of-freedom (DOF) spur gear system model. The mode characteristics of the gear system model are analyzed and verified by performing finite-element analysis (FEA). From the results, the bearing stiffness on the radial clearance was more sensitive under low-load conditions compared to high-load conditions. The bearing stiffness significantly affected the gear dynamics in the low-frequency region, while the mesh stiffness affected the high natural frequency.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.8
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• pp.847-853
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• 2011

In this study, a hybrid powder-extrusion process involving the control of temperature dwelling time for improving the formability of Zn-22Al powder was developed and the effect of dwelling time on the mechanical properties of a spur gear with a pitch circle having a diameter of 1.8 mm was investigated. General extrusion experiments were carried out at different temperatures such as 290, 300, and $310^{\circ}C$. Spur gears with good qualities and without any surface defects were obtained in the case of extrusion temperature of $310^{\circ}C$ and ball-milling duration of 32 h. The Vickers hardness distribution was non-uniform, and after the sintering process, an internal crack was generated because of the different deformation energy between gear central part and teeth. To overcome the abovementioned problems, research on controlling the dwelling time of the extrusion temperature in the powder-extrusion process was carried out. Good-quality spur gears were obtained when the dwelling time was 15 min.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.2
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• pp.121-130
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• 2023

Finite element analysis is widely used to predict the structural stability and tooth contact performance of gears. This study focused on the effect of finite element modeling conditions of a spur gear on the simulation result and the model simplification. The gear body and teeth, teeth width, configuration of mesh, frictional coefficient, and simulation time interval (gear mesh cycle division) were selected for model simplification for gear analysis. The static transmission error during a single-gear mesh cycle was calculated to represent the performance of the gear, and the elapsed time was measured as a simplification factor. Contact stress distribution was also checked. The differences in maximum transmission error and elapsed time depending on the model simplification methods were analyzed. After all simplification methods were estimated, an optimal combination of the methods was defined, and the result was compared with that of the most detailed modeling methods.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.28-31
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• 2002

In this study, we develop automatic design program, which create 3D model of spur gear and helical gear used VisuaILISP and create helical gear in the CATIA using 2D profile of gear. This model become the standard model, which give not only in itself mold information but also computer processed product with measuring date. Spur gear require mathematical examination of involute curve and trocoidal fillet curve. Automatic design program, which have a mathematical development create the profile of spur gear.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.3
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• pp.103-110
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• 2014

In this study, spur and helical box models of an existing machine tool are investigated using structural and fatigue analyses. As the helical box model is shown to have less stress and deformation than those characteristics of the spur box model, the helical box has more strength and more transmission efficiency on the structure. In terms of fatigue analysis, the helical box model has more repeated fatigue strength than that of the spur box model. These study results can be effectively utilized in the design of real gear boxes of machine tools by anticipating and investigating prevention and durability against damage.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.4
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• pp.358-364
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• 2012

This work dealt with dynamic characteristics of spur gear and helical gear system to understand the gear vibration and noise. To find out dynamic characteristics in the gear system, a finite element model and an analytic model for the gear system were used. Using the models, the natural frequency and mode-shape characteristics of spur gears and helical gears were calculated. Two models show that natural frequencies of helical gears were lower than those of spur gears. Mode-shape characteristics of gear pairs by analytical model and some issues of finite element modeling were also discussed. Impact test was used to validate the finite element model.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.2
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• pp.171-176
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• 2002

This paper is the study on stress analysis of spur gear using a finite element method. Gear drives constitute very important mechanisms in transmitting mechanical power processes compromising several cost effective and engineering advantages. The load transmission occurred by the contacting surfaces arises variable elastic deformations which are being evaluated through finite element analysis. The automatic gear design program is developed to model gear shape precisely. This gear design system developed was used by pre-processor of FEM packages. The distribution of stresses at contacting surfaces was examined when a pair of gear contact.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.05a
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• pp.259-266
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• 2002

The basic concept of 'tooth profile modification' is to change a part of the involute profile to reduce the load in that area and appropriate profile modifications can help gears to run quietly and resist scoring, pitting and tooth breakage. In this study, the modification of tooth profile to make a smooth transmission of the normal loads in spur gears has been developed. The modified tooth profile has been determined by the total deflection at contact points. We use the AGMA Standard to design basic gear profile, We also developed a gear design Program using tooth profile modification

• Journal of the Korean Society for Precision Engineering
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• v.19 no.10
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• pp.202-211
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• 2002

The basic concept of 'tooth profile modification' to change a part of the involute profile to reduce the load in that area and appropriate profile modifications can help gears to run quietly and resist scoring, pitting and tooth breakage. In this study, the modification of tooth profile to make a smooth transmission of the normal loads in spur gears has been developed. The modified tooth profile has been determined by the total deflection at contact points. We use the AGMA Standard to design basic gear profile. We also developed a gear design program using tooth profile modification.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.9
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• pp.1005-1012
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• 2014

Gears are critical elements in automobiles, and their use as power transmitting machine elements in engineering applications is quite extensive. In the areas of contact between gear teeth, the condition of a gear is likely to deteriorate due to contact fatigue, wear, material defects, lubrication failure, etc. Thus, it is necessary to monitor its condition to ensure smooth power transmission. Gear teeth deterioration causes failures such as abrasive wear, scuffing, pitting, and spalling. These failures lead to a higher level of vibration signals in the gear system. This paper presents the results of an experiment on the surface fatigue wear of a spur gear system. The correlation between the estimated specific film thickness, statistical parameter of the vibration signals, and Stribeck curve was considered in this study.