• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.8
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• pp.1029-1033
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• 2013

Elliptical gear is used as a rotor of oval flowmeter. The elliptical gear can assist water flow-rate measurement by the space of the elliptical shape. Presently, elliptical gears have been processed using hob tool imported from Japan. But if it were not for the technical cooperation with Japan company, the Elliptical gears can't be processed. The purpose of this study is developing a domestic technology for elliptical gears and overcoming the dependence of foreign technical skills. It will bring the import substitution effect. In case of pressure angle $20^{\circ}$, the elliptical gears have an interference of tooth. The increase of pressure angle makes the root of a tooth thick and the top of tooth thin. By results of this study, tooth of elliptical gear was designed and verified through the 2D and 3D simulation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.11
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• pp.1453-1459
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• 2011

A roller pinion gear (RPG) system composed of either a pin or a roller and its conjugated cam gear can improve the gear endurance from that of a conventional gear system by reducing the sliding contact while increasing the rolling motion. In this paper, we first proposed the exact cam gear profile and the self-intersection condition obtained when the profile shift coefficient is introduced. Then, we investigated the Hertzian contact stresses and the load stress factors while the varying the shape design parameters to predict the gear surface fatigue life, which is strongly related to the gear noise and vibration at the contact patch. The results show that the pitting life can be extended significantly by increasing the profile shift coefficient.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.256-262
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• 2016

This study performed the back-pressure cold forging analysis to minimize the non-forming area of gear teeth for the output hub and reaction hub in automatic transmission. Two important factors of the back-pressure cold forging process, the load of the punch and the backup force applied to the sleeve, were determined through displacement control analysis. The non-forming area of the gear teeth was compared with both cases of the displacement control analysis and load control analysis, and their solution is similar to the measuring result of a real workpiece. The results show that the load of the punch is dependent on the reduction area of the workpiece, and the backup force applied to the sleeve is determined with regard to the cross-section-area of sleeve. This analysis procedure can be useful and effective in determining the manufacturing condition of the back-pressure cold forging process to minimize the non-forming area.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.2
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• pp.296-303
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• 1987

The composite gear which is composed of involute curve and circular arc has been studied. In the vicinity of pitch point, its profile is an involute curve, and in the dedenum, a circular arc. The curve in the dedendum is generated by the circular arc of the mating gear. Though the available range between minimum and maximum radius of circular arc can be given by existing tooth profile equation, there was no formulation which relates design parameters to the desired radius. It is attempted to get the formula for the radius of circular arc as a function of design parameters, such as unwounded angle, number of teeth, module, and pressure angle. The radius of circular arc, the chordal tooth thickness at working root circle, nominal bending stress, Hertz stress and contact ratio obtained from derived formula are compared with those of the existing design criteria. And these are compared with those of involute gear.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.4
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• pp.159-166
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• 2005

This study deals with the correction of gear tooth profile error by finish roll forming. First, we experimentally confirmed that the tooth profile error is a synthesis of the concave error and the pressure angle error. Since various types of tooth profile errors appear in the experiments, we introduced evaluation parameters for rolling gears to objectively evaluate profile quality. Using these evaluation parameters, we clarified the relationship among the tooth profile error, the addendum modification factor (A. M. factor), and the tool loading force. We verified the character of concave error, pressure angle error, tool loading force and number of cycles of finish roll forming by using a forced displacement method. This study makes clear that tool loading force and number of cycles of finish roll forming are very important factors that affect involute tooth profile error. The results of the experiment and analysis show that the proposed method reduces concave and pressure angle errors.

• Journal of Power System Engineering
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• v.14 no.3
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• pp.64-70
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• 2010

In this study, designing of precise linear transferring device which can be applied to industrial machine and robot industry has been introduced. The direction of power flow and output feature are similar to current Rack-Pinion type. However, unlimited length extensity via rack modulizing, and securing high velocity transportation have been realized by applying Pin-Pinion Gear type at the operation part. The analysis has been calculated to obtain the Pin-Pinion Gear's optimized tooth profile. As a result of research, it is impossible to control precisely even overlap at the teeth of involute and sprocket. Because they have peculiar gearing structure. Therefore, modified cycloid tooth has been proposed to perform high velocity, precise control without backlash.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.2
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• pp.162-167
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• 2003

This paper is the study on stress analysis for tooth modification of high speed gear using a finite element method. Gear drives constitute very important mechanisms in transmitting mechanical power processes which compromise several cost effective and engineering advantages. The load transmission which occurred by the contacting surfaces arises variable elastic deformations evaluated through finite element analysis. The automatic gear design program was developed to model gear shape precisely. This developed gear design system was used by pre-processor of FEM packages. The distribution of stresses at contacting surfaces was examined when gear tooth contacts. And this paper proposes a method for the tooth modification after carrying out stress analysis using a finite element method.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.8
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• pp.1057-1067
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• 2010

Vibration and noise analysis as well as strength of gear teeth, gear profile design are considered in order to develop the multi-gear train devices of synchro system for the guns of a warship. A new approach to the critical speed calculation of practical industrial multi-mesh geared system is presented. A transfer matrix model based on Hibner's branch method is developed and the natural properties of the branched rotor system are calculated with using the ${\lambda}$-matrix formulation. A Campbell diagram, in which the excitation sources caused by the mass unbalance of the rotors and the transmitted errors of the gearing are considered, shows that, at theoperating speed, there are not the critical speed.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.2
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• pp.102-112
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• 1997

This paper describes the method that can construct kinematically admissible velocity fields for forging of gear-like components which have tooth shape around the cylinder. The kinematically admissible velo- city fields for the various gear-like components, involute spur gear, trapezoidal spline, square spline, ser- ration and trochoidal gear, were constructed by pilling up the velocity components according to the shape of tooth and billet. The billets, of hollow and solid, were Al 2218 and 2024. To verify the method, the analyses and experiments were carried out and compared with each other. For analyses, the half pitches of com- ponents were divided into several deformation regions based on their tooth profile. A neutral surface was used to represent the inner flow of material during forging. Its location varied with the energy optimazation and its contour varied with the number of teeth. In experiment, the contour of material filling up the tooth zone is hyperbolic curve caused by the frictional drag on the interface of die-wall/workpiece but, in the analysis, it is an arc which retains the same contour during all forging operation.

• Journal of the Korean Institute of Gas
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• v.26 no.2
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• pp.21-26
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• 2022

Since the four-wheel drive transmits the driving force to all four wheels, the traction with the road surface increases, thereby increasing the driving force. However, it has the disadvantage of lowering fuel efficiency. Therefore, four-wheel drive is commonly used as a method of converting to optional four-wheel drive when necessary while driving in two-wheel drive. This selective four-wheel drive converts the driving force by mechanically changing the electric signal sent by the driver in the transfer case. In this study, in order to mechanically change the electrical signal, a reducer is applied to the motor to increase the torque to perform the function. Therefore, in this study, a reduction mechanism applicable to the motor inside the transfer case applied to convert the drive is derived, and the reduction ratio applying the planetary gear type is optimized accordingly. And based on the derived reduction ratio, two sets of planetary gears using a ring gear in common were applied to develop a planetary gear tooth type in which the input shaft and output shaft are decelerated in the same phase. Optimization design was carried out.