• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.2
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• pp.84-89
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• 2011

This paper studied the carburizing of chromium molybdenum steel which the heat treatment effect of gear geometric tolerance, OPD, Runout, the surface hardness, the maximum hardness, the core hardness and the bending fatigue strength were investigated. Firstly, the deformation is observed, and the results of circularity, squareness, OPD and Runout of SCM822, SCM425, and SCM415 are obtained in order. Secondly, in order to investigate the gear hardness, the surface hardness, the maximum hardness and the core hardness of SCM822, SCM425, and SCM415 are obtained; and the surface hardness of SCM822 is about 10% higher than SCM415's, and about 3% higher than SCM425's. Thirdly, the fatigue strength of SCM822 is about 10% higher than SCM415's, and about 7% higher than SCM425's in the fatigue test results. At last, for the purpose of the minimum deformation of heat treatment, and also the improvement of fatigue strength, the best gear material is SCM822 in this test.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.6
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• pp.195-200
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• 2012

In this study, parameters and requirements of an 120kW class monorail planetary gearbox was analysed and the adaptive planetary gearbox design was selected. The specification of the sun gear, planetary gear and carrier was set and the profile & lead was optimized. The mechanical efficiency of the optimized one and the original one was observed. Dynamo-tester system was used to observe the mechanical efficiency of the planetary gearbox. A dynamo unit was connected with the planetary gearbox which straightened through the motor by a coupling. The standard tooth shape planetary gearbox and modified tooth shape planetary gearbox were used as test pieces and the rotation speed was set from 600 to 6000rpm with 600rpm, 2.5min one step. In order to check the mechanical efficiency of the planetary gearbox, the tests were done as follows. 1) The power loss between driving motor and dynamo tester. 2) Temperature variation by different rotation speeds. 3) Noise variation by different rotation speeds.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.6
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• pp.46-53
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• 2014

An automatic grease lubricator provides an adequate amount of fresh grease constantly to any type of rotating machine to minimize friction heat and reduce friction loss. This study seeks to develop an automatic grease lubricator by means of rapid prototyping with a gear-driven mechanism and a controlled operation time. The ultimate design is to lubricate an adequate amount of grease by a simple dip-switch clicking mechanism according to an advanced set cycle. The backlash of the gear was minimized to increase the power, and to increase the power of the mechanism, the binding frequency and the thickness of the coil were changed. To control the rotation cycles of the main shaft according to certain set numbers, different resistances and chips were used in the design of the circuit which controls the electrical signals via a pulse. A digital mock-up was analyzed and the rapid prototyping (RP) trial products were tested with a PCB circuit and grease. An evaluation of the outlet capacity of RP trial products was conducted, as the friction caused by the outlet on the wall surface was an important factor in the operation of the equipment. Finally, a finishing process was applied to decrease the roughness of a surface to a comparable level to test the performance of the product.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.6
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• pp.15-20
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• 2017

This study analyzed the load change of the gear generated by the operation of the vehicle recliner through Finite Element Analysis. The basic model of the recliner used was a commercial product, and the effect of the seat frame was excluded. The load conditions applied to the recliner were set considering gravity, the mass of the seat's back frame, and the weight of a person. The operating mode was set to move the seat back from the vertical to the reclined position. As a result, it was found that the tooth bending amount of the gear rim and wheel increased from the cam rotation angle of 450 degrees, and a change in the contact ratio occurred. Furthermore, excessive torque fluctuations occurred in the ranges of 390 to 450 and 750 to 710 degrees. It was found that this occurred in the region of about 30 degrees before and after the point where the x-axis direction load is larger than the y-direction load. From this torque fluctuation it was determined to likely to cause chattering noise.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.3
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• pp.342-349
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• 2011

The purpose of this paper is to describe experimental results about the butt welding and bead on plate welding of the high power Continuous Wave (CW) Fiber laser for Ultra-low carbon Interstitial Free(IF) steel plate for gear part of car. After being welded of the gear parts by the fiber laser and electron beam Microstructures of melting zone had been mixed acicular, granular bainitic, quasi-polygonal and widmanstatten ferrite because of a radical thermal diffusion after welding, difference of critical volume and grain size. As a result of experiment, when gear parts were welded by the fiber laser and electron beam, the fiber laser welding has been stable properties without internal defects more than the electron beam welding. Therefore it has the very advantages of welding high quality and productivity more than conventional melting method. The optimal welding processing parameters for gear parts were as follows : the laser power and welding speed were 3kWatt, 30mm/sec respectively. At this time heat input was $21.2{\times}10^3J/cm^2$.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.2
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• pp.130-136
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• 2022

Reducing production costs through net-shaped cold forging is an important aspect in the automobile industry. In this study, we intend to produce a net-shaped electronic parking brake (EPB) serration gear for automobiles, using multi-stage cold forging. These serrations are then assembled to the reduction gear of an EPB actuator. The forging process of the serrations and the cold forging design were verified through finite element analysis (FEA) in order to evaluate metal flow. The forging machine was selected by checking the load using FEA. Based on the FEA results, molds were designed, and parts were made using multi-stage cold forging to produce a net-shaped serration gear.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.8
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• pp.1506-1511
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• 2002

A computer aided expert system fur spur, helical, bevel and worm gears was newly developed by using AutoiCAD system and its AutoLISP computer language in the present study. Two methods are available for a designer to draw a gear. The first method needs the gear design parameters such as pressure, module, number of tooth, shaft angle, velocity, materials, etc. When the gear design parameters are inputted, a gear is drawn in AutoCAD system and maximum allowable power and shaft diameter are calculated additionally. The second method calculates all dimensions and gear design parameters to draw a gear when the information such as transmission, reduction ratio, nm, materials and pressure are inputted. The system includes four programs. Each program is composed of a data input module, a database module, a strength calculation module, a drawing module, a text module and a drawing edit module. In conclusion, the CAD system would be widely used in companies to find the geometric data and manufacturing course.

• International Journal of Precision Engineering and Manufacturing
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• v.1 no.1
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• pp.5-14
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• 2000

In the design of epicyclic gearing, the analysis of interference and mechanical efficiency is an important index. As an applied way, epicyclic gearing can be used for planetary gear drive and differential gear unit. In case that one of its components is fixed with intend, it is called planetary gear drive. On the contrary, in case that no component is fixed, it is called differential gear unit. In this paper, various design constraints and interferences are defined for 2K-H I type epicyclic gearing which is a basic arrangement of diverse epicyclic gearings. And various interferences are analyzed, and mechanical efficiency is calculated in case that 2K-H I epicyclic gearing is used for a differential gear unit as the change of gear ratio, cutter pressure angle, addendum modification coefficient. As that results, trend of mechanical efficiency is investigated in the ranges of addendum modification coefficients which would not lead to interferences, and the optimal range of addendum modification coefficient which can generate the maximum mechanical efficiency are presented. In order to prove results of theoretical efficiency analysis, experimental studies are performed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.270-275
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• 2008

The straight bevel gear for automobile part has been manufactured by the cold forging instead of the gear machining tool for the mass production. The application to CAD/CAM system has been necessary in order to develop the precision product quickly by forging through the minimization of trial and error and confirm the reproducibility. In the study, the straight bevel gear with the crown teeth has been modelled by the CAD/CAM system. The master gear after the gearing test has been machined after the modelling, NC data generation and verification. The die for forging and the jig for machining has been manufactured using the master gear.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.144-148
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• 2007

In this paper, we present a systematical procedure to develop a precision enclosed die forging process for a bevel gear of a passengers' car. The detailed procedure involves bear gear CAD modeling, process design and CAE simulation, CAM and die making, material preparation, and prototype manufacturing using both the technologies and machines accumulated and equipped in the technology innovation center(TIC) of Gyeongsang National University. It is demonstrated that the presented approach guarantees bevel gears with the second KS grade quality, which can be used for the differential gear of the passengers' car.