• Journal of the Korean Society of Manufacturing Technology Engineers
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• 제23권2호
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• pp.109-117
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• 2014

This paper reports a method to modify the gear tooth profile of a wind turbine gearbox to reduce the noise caused by the impact of the gear teeth. The major causes of tooth impact are the elastic deformation of the gear teeth, shafts, and case of the gearbox under loading, and the fabrication tolerances in gear manufacturing. In this study, the tooth profile was modified considering the elastic deformation of the gear tooth and the tooth lead modification to compensate for tooth interference in the lead direction as a result of shaft deformations. The method was applied to the gearbox of a 2.5MW wind turbine, and the transmission error was characterized before and after modifying the gear teeth. For the modified gear teeth, the transmission error (67.6%) was lower by 17.8%. Additionally, the gear contact stress was reduced by 6.3%, to 22.3%.

• Journal of the Korean Society for Precision Engineering
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• 제1권3호
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• pp.85-94
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• 1984

The WILDHABER-NOVIKOV gear, one of the circular arc gears, has the large contact area between the convex and concave profiled mating teeth, moves from one end of the tooth to the other axially making a face contact. Hence it provides a large load capacity than the Involute gear and still satisfying the law of gearing. In order to analyze the gear stress, a photoelastic investigation was carried out. Photo elastic model of the WILDHABER-NOVIKOV gears were made of Araldite CT200 in this investigation. For both the many teeth gear and the few teeth gear segments, External gears of all addendum type WILDHABER-NOVIKOV gear and the involute gear were tested. Included were the models with various profile raddi at the same pressure angle 20 .deg. and module 13.5. The flank stresses and fillet stresses of these gears were observed in each case and compared with those of gears. From this investigation, the following results were obtained. A. In the case of having many teeth gear: As the profile radius is increased, the fillet stresses of the WILDHABER-NOVIKOV gear become the same or less than that of the INVOLUTE gea, and the flank stress becomes smaller than that of the INVOLUTE gear. Therefore the better design condition is satisfied with a large profile radius. B. IN the case of having a few teeth gear: As the profile radius is increased the flank stress of WILDHABER-NOVIKOV gear becomes smaller than that of the INVOLUTE gear, but the fillet stresses become larger than that of the INVOLUTE gear. Therefore the larger design condition is satisfied with small profile radius.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제27권5호
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• pp.758-763
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• 2003

A profile shifted gear system was analyzed to select the optimum profile shift coefficient, which minimizes gear teeth deflection. Contact force and deformation overlap were calculated by means of FEM and contact theory. The deformation overlap is suggested for an effective indicator to represent the whole deformation of gear system. The optimum value of profile shift coefficients was presented with respect to the deformation of gear system.

• Journal of the Korean Society of Mechanical Technology
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• 제13권4호
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• pp.117-124
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• 2011

A gear pump is a type of pump that displaces a volume of fluid by physical or mechanical action, or positive displacement pump. Power is applied to one of the gears and transmitted to a second driven gear via meshing teeth. This paper describes the hydraulic gear pump for an elevator. In gear pump, since geometrically special forms of gear tooth, 'Pulsations' is always caused in the delivery pressure and quantity. In other words, it is found that the number of delivery pressure pulsation per each revolution is always equal to that of the gear-teeth of the gear, which is coincident with the pulsation of the ideal delivery quantity. Some experimental results are given to verify the effectiveness of the developed pump.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 한국윤활학회 2002년도 제35회 춘계학술대회
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• pp.200-206
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• 2002

Pressure and film thickness of contacting surfaces between teeth of the involute spur gear in lubricated condition were studied by a numerical method. Dynamics of the gear and pinion was considered to gel ail accurate initial clearance between gear teeth. The 3-dimensional non-steady elastohydrodanamic lubrication analysis on the gear teeth showed a slight higher pressure at the inlet region of the contacting face as well as pressure spike at the outlet region and a more thick film thickness than that of steady condition.

• Journal of the Korean Society of Industry Convergence
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• 제25권6_1호
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• pp.941-952
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• 2022

In this study, additive manufacturing technology was applied to restore a planner miller that was unusable due to aging. The drive spur gear of the planner miller was inoperable due to many defects in the teeth. The shape of the defective gear teeth was restored by deposition of the defective teeth using the DED method. However, as the location of the deposition head and the location of the set origin became farther, the deposition shape was different from the modeling shape. Nonetheless, since the modeling of the deposition part was designed to be larger than the tooth shape of the original gear, it was possible to completely restore all gear teeth through post-processing. The arrangement interval of the flow lines of the deposition part was narrower than that of the substrate. The hardness of the substrate was 172 HV, and that of the deposition part was 345 HV, which was twice as high as that of the substrate.

• Design & Manufacturing
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• 제6권2호
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• pp.54-58
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• 2012

A counter shaft gear is an important part in the transmission system of vehicle. Its shape is relatively complicated and should meets high strength. Traditionally it has been manufactured as follows; the counter shaft gear has consisted of a clutch and helical body with teeth which are forged and machined for teeth respectively and then attached by frictional welding. In this study, a new hot forging process was proposed and designed so that the counter shaft gear is formed as one body without divide it into two parts. Furthermore, the precision forging process has been developed for the clutch teeth without additional grinding.

• Tribology and Lubricants
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• 제39권5호
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• pp.173-182
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• 2023

The composite planetary gear reducer, a power transmission component of armored vehicles, operates at a high torque and is used in severe environments such as mountain, gravel or unpaved roads. Therefore, they must be designed and manufactured to have high durability. To design such a planetary gear reducer, there are numerous specifications to validate, such as selecting the module and the number of teeth of each gear satisfied the requirements, and calculating gear specifications and durability strength. Because planetary gears constitute a combination of several gears, there are many restrictions and interferences in selecting the number of teeth and addendum modification coefficients, and designing the tooth shape. Developing an auto design program is necessary to design various planetary gears more conveniently and quickly. In this study, a planetary gear reducer design software, widely used in various machines and armored vehicles, was developed. This design software can automatically select the number of teeth and modules of the gears, calculate specifications and quickly evaluate its fatigue durability strength and scoring failure according to the planetary gear reducer design theory.

• Design & Manufacturing
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• 제6권2호
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• pp.6-11
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• 2012

A counter shaft gear is an important part in the transmission system of vehicle. Its shape is relatively complicated and should meets high strength. Traditionally the counter shaft gear has been manufactured as follows; a spline body is firstly machined for teeth and then attached to the main gear body by frictional welding, and finally is finished by grinding. Therefore it is necessary to develop a new manufacturing technology eliminating both frictional welding and grinding processes. In this study, a new hot forging process was proposed and designed so that the spline body with teeth and main gear body are formed as one body. Finite element simulations and experimental works were peformed for design of forging processes to get the quality final precision-forged product. Consequently the most suitable blocker process could be obtained.

• Transactions of the Korean Society of Automotive Engineers
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• 제6권6호
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• pp.243-251
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• 1998

A method of establishing the tooth modification for gear transmission of vehicles to reduce gear whine noise, caused by tooth impact phenomenon of mating gear, is introduced. The major causes of tooth impact are due to the deflections of gear teeth and shafts of transmission with the loaded condition including various kinds of manufacturing errors. The theoretical shape of tooth surface to avoid tooth impact is derived by the amount of elastic deformation of gear teeth and shaft and overall manufacturing error of machine tool. The surface function is converted with respect to the conventional commercial data usually communicated to the gear inspection system. The proposed method is applied to the gearbox of four wheel drive vehicle and shows the gear whine noise decreased to the 8 dB in the sound level.