• Proceedings of the KSR Conference
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• 2002.05a
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• pp.399-403
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• 2002

The transmission system of high speed train serve in the severe condition compared with those of other trains, namely, they have to transmit high power to run with high speed and they have to make maximum use of the limited space. To clarify the strength of gear for Korea High-Speed Train, a bending fatigue test of gear specimen is performed and compare with actual gear's. From this result, specimen test is useful to infer S-N curve and endurance limit of actual gear that much time and expense are consumed.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.92-97
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• 2004

The aim of this study is to estimate the strength of injection molded plastic stepped gear. We considered stepped gear as plate model which are fixed by two edges. While, on the other sides are free. Normal gear is calculated by Lewis formula which can be derived quite simply from the equation for the stress at the root of a cantilever beam. Stress ratio(step factor) is represented for the ratio of the bending stress of normal and the bending stress of stepped gear, and it is plotted by face width factor. This study is propose the step factor added in Dupont equation which are strength estimation of step gear

• Journal of the Korean Society for Precision Engineering
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• v.14 no.9
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• pp.61-67
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• 1997

Hardened layer and compressive residual stress created by carburized treatment effect on bending strength of gear massively. Also, shot peening treatment improves the strength of carburized gear as it does the hardness and residual stress of surface layer. In these days shot peening techniques are welcomed as one of physical improvement ways around the surface of materials. It is used widely because qualitative analysis of shot peening has become possible and surface treatment can be done with very little costs comparaed to other surface improvement methods. Therefore this study investigates the effect of shot peening in surface shape and bending fatigue strength after doing many kinds of shot peening treatments, then doing fatigue test and also explained characteristics of shot peening gear.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.4
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• pp.38-43
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• 2011

Industrial reducer is in general use to Deck Crane. High-precision and high-efficient reducer is minimized the power-loss and energy-loss of a machine. So it contribute the price reduction and life extension. Reducer is usually using the Planetary gear reducer. Planetary gear reducer is composed the sun gear, planet gear, internal gear and casing. Industrial reducer's wear and breakage have a short-life. To solve this problem, it is using the profile-shifted-gear or tooth modification. This study was carried out the effect of addendum modification coefficient on tooth fillet bending strength to planetary reducer. Tooth fillet bending stress is calculate. And all parameter were expressed the function of addendum modification coefficient. And then stress concentration factor of tooth fillet curve was express the function of addendum modification coefficient using comparison between theory and finite element analysis.

• Tribology and Lubricants
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• v.38 no.1
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• pp.22-26
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• 2022

A 1.7-ton grade small excavator is a construction equipment that can perform various functions in limited spaces where heavy equipment cannot enter easily. Owing to the recent acceleration of urbanization, it has been used increasingly in drainage and gas pipes, as well as for road repair works in urban areas. The power train of a traveling reducer for a 1.7-ton grade small excavator utilizes a complex planetary gear system. Complex planetary gears are vital to the power train of a traveling reducer as it mitigates the fatigue strength problem. In the present study, the specifications of a complex planetary gear train are calculated; furthermore, the gear bending and compressive stresses of the complex planetary gears are analyzed to achieve an optimal design of the latter in terms of cost and reliability. In this study, the actual gear bending and compressive stresses of a planetary gear system are analyzed using a self-developed gear design program based on the Lewes and Hertz equation. Subsequently, the calculated specifications of the complex planetary gears are verified by evaluating the results with the data of allowable bending and compressive stress based on curves of stress vs. number of cycles of the gears.

• Journal of Drive and Control
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• v.13 no.4
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• pp.45-51
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• 2016

The power train of a hydro-mechanical, continuously variable transmission for forklifts makes use of hydro-static units, hydraulic multi-wet disc brakes & clutches, and complex helical & planetary gears. The complex helical & planetary gears are very important parts of the transmission because of a strength problem. In the present study, we calculated the specifications of the complex helical & planetary gear train, and analyzed the gear bending and compressive stresses of the gears. It is necessary to analyze the gear bending and compressive stresses thoroughly for optimal design of the complex helical & planetary gears with respect to cost and reliability. In this paper, we analyze the actual gear bending and compressive stresses of complex helical & planetary gears using the Lewes & Hertz equation, and we also verify the calculated specifications of the complex helical & planetary gears by evaluating the results of the data of allowable bending and compressive stress using the Stress vrs Number of Cycles curves of gears.

• Journal of Powder Materials
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• v.4 no.4
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• pp.258-267
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• 1997

The powder forging process is an attractive manufacturing route for bevel gears. It offers beneficial material utilization and the minimization of finishing operations over that of conventional hot forging. The paper describes the process conditions for the powder forging of bevel gear, for example, powder alloy design, preform design, deformation of sintered preform, forging processes. The characteristics of prototype gear are investigated with microstructure, the density distribution, surface roughness of tooth, bending strength test of tooth, etc. The results of the bending strength test may prove the mechanical properties of powder forged gear.

• Journal of the korean Society of Automotive Engineers
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• v.6 no.3
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• pp.45-54
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• 1984

Bending strength of an internal gear tooth is discussed as tooth form factor taking into account the actual stress magnitude. Stress analysis was carried out by the finite element method(FEM) for the calculation of tooth form factor of an internal gear. This paper also investigated the influences of number of teeth and addendum modification coefficient of the internal gear and the influences of number of teeth, addendum modification coefficient, pressure angle, radius of rounding of tooth tip, and bottom clearance coefficient of the pinion-shaped cutter on tooth form factor of internal gear. Generalizing the resultant data, a simple formula for the tooth form factor of an internal gear was derived for the calculation of tooth bending strength of an internal gear.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.7
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• pp.66-73
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• 1995

Rating systems of bevel gears(straight, spiral, and zerol bevel gears) which are commonly used as power transmission devices for non-papallel axes are developed on the personal computer, which analyze and/or evaluate the gear design and the service performance at the point of view of strength and durability. The typical considerations of the ratings are the bending strength, the surface durability, and the scoring resistance. The ratings are carried out using the reliable standards of AGMA & Gleason Works. Therefore, the system is built so that the variables or factors considered differently in those standards and the strength, dura- bility, and scoring partially in Gleason are appraised seperately by each method, and a series of the estimation processes is integrated into the system so as to compare each result. The developed rating systems can be used in the initial stage of gear design process, and also a better design can be performed by the evaluation of the initial design at the view point of gear strength and durability. Additionally, it is useful for the trouble-shooting of bevel gear system and to the purpose of introducing the methods for maintaining design strength in service, with appraising the gear strength after design or with appraising the influencing factor as a whole. Therefore, this rating systems can help the aim of design automation of bevel gears.

• Journal of Drive and Control
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• v.12 no.4
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• pp.77-81
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• 2015

In general, the gears of mixer reducer for concrete mixer truck make use of the differential type planetary gear system to rotate mixer drum smoothly on the initial conditions. The planetary gear system is very important part of mixer reducer for concrete mixer truck because of strength problem. In the present study, calculating the gear specifications and analyzing the gear bending & compressive stresses of the differential planetary gear system for mixer reducer are necessary to analyze gear bending and compressive stresses confidently, for optimal design of the planetary gear system in respect to cost and reliability. As a result, analyzing actual gear bending and compressive stresses of the planetary gear system using Lewes & Hertz equation and verifying the calculated specifications of the planetary gear system, evaluate the results with the data of allowable bending and compressive stress from the Stress-No. of cycles curves of gears.