• Transactions of Materials Processing
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• v.25 no.4
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• pp.268-274
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• 2016

In the automotive seat industry, the use of a fine blanking press is important for manufacturing of high precision products. Among them, a gear part which is a main component of an automotive seat recliner is generally manufactured by fine blanking press. However, the use of conventional mechanical press has been increasing in manufacture of gear part because of low productivity of fine blanking press. In this study, new forming process is suggested to fabricate the gear part with high precision by using mechanical press. The effect of flow restriction die (FRD) which has the restriction of blank edge on dimensional accuracy is investigated by FE-analysis. FE-analysis results for different conditions of FRD indicated that FRD has high dimensional accuracy with the lowest roll-over and the highest perpendicularity of gear part. After application to fabrication of the gear part using mechanical press, the measured dimensional characteristic was compared with the required specification of final product. In addition, results of the performance test showed that the product fabricated by developed process satisfied the required strength and durability. The results show that the suggested forming process by using FRD and mechanical press can replace fine blanking on the viewpoint of dimensional accuracy and productivity.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.2
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• pp.64-72
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• 2022

Gear designers need to select the proper tolerances for deviations in both the center distance and parallelism of axes because these deviations cause high stresses and lead to fatigue breakage of the teeth. In this study, a three-dimensional finite element analysis model was developed for a helical gear used in metro vehicles, and a bending stress analysis method for gear pairs was established according to the contact position change. Using this model, the effect of shaft misalignment due to the center distance and shaft parallelism deviations on the bending stress of the gear was analyzed. As a result, the magnitude of the bending stress changed nearly linearly with the change in the center distance deviation. The tooth contact of the helical gear is biased toward the end of the tooth width when the parallelism deviations of the shaft occur, and the tooth root bending stress increases.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.6
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• pp.897-902
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• 2012

Low speed vehicle(LSV), golf carts have unique requirements to differential gear design. For double axle torque LSV differential loading conditions were determined with the help of analytical model and ANSYS finite element analysis. With stress safety factor 3.15, fatigue safety factor 1.08 and fatigue life 106 cycle ring gear teeth strength analysis is performed and structure design optimized. This allows reducing overall cost of differential unit.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.311-314
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• 2008

The volume and size of the wind turbine gearbox has been increased with increasing transmitted power. The optimal sizing of gearbox is important due to limited space on the nacelle. The power-split type planetary gear train has been regarded as a better solution than conventional type from the point of view of the volume and weight. The purpose of this paper is to optimize the volume and weight of the gearbox by the analysis of structural characteristics and evaluation of strength of the power-split type planetary gear train.

• Journal of Power System Engineering
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• v.21 no.1
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• pp.5-10
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• 2017

Pitch drive system in wind turbine is composed by the planetary gear system to satisfied its required performance such as long life and light weight for gear train. When the planetary gear system can reduce its volume and weight, the power consumption of the wind turbine can be reduced. In this study, the planetary gear system of the pitch drive system in medium-sized wind turbine is obtained for weight reduction by shape optimization method. And the planetary gear system is verified for their strength by the structural analysis.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.11
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• pp.73-82
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• 2008

A dynamic model of reducer for generating facility of electric pourer having bevel gear pair and planetary gear train is developed by lumped method. The model accounts for the shaft and bearing flexibilities, gyroscopic effects and the force couplings among the transverse and torsion motions due to gearing. Vibration/noise analysis as well as strength of bevel gear pair and planetary gear train are considered. Exciting forces of high reducer for generating facility of electric power areconsidered as the mass unbalance of the rotors, misalignment and a function of gear transmission error. A Campbell diagram, in which the excitation sources caused by the mass unbalance of the rotors, misalignment and the transmitted errors of the gearing are considered, shows that, at the operating speed, there are not critical speed.

• Korean Journal of Agricultural Science
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• v.46 no.4
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• pp.723-735
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• 2019

The power-train is the most important component of an agricultural tractor. In this study, the strength of the driving gear transmission of an 82 kW-class tractor was analyzed using equivalent torque during plow tillage. The load measurement system consisted of an engine revolution speed sensor, torque-meters, revolution speed sensors for four axles, and pressure sensors for two hydraulic pumps. The load data were measured during plow tillage for four speed stages: F2 (2.78 km/h), F5 (5.35 km/h), F7 (7.98 km/h), and F8 (9.75 km/h). Aspects of the gear-strength such as bending stress, contact stress, and safety factors were analyzed under two torque conditions: the equivalent torque at the highest plow load for the F8 speed stage and the maximum engine torque. The simulation results using KISSsoft showed that the maximum engine torque conditions had a lower safety factor than did the highest equivalent torque condition. The bending safety factors were > 1 at all gear stages, indicating that gear breakage did not occur under actual measured operating conditions, nor under the maximum torque conditions. However, the equivalent torque condition in the contact stress safety factor was > 1, and the maximum torque condition was < 1 at the first gear pair. The method of analysis using the equivalent torque showed lower stress and higher safety factor than did the method using maximum torque. Therefore, when designing a tractor by applying actual working torque, equivalent torque method would support more reliable product development.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.44-48
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• 2003

In metal working, cold forging that has profit to satisfy dimension accuracy is using in various manufacturing products. Recently, most of the interest thing is precision forging of gear, Gear forging product is more strength than broaching gear, and it has many advantages with reduction of factory expenses. The reason of difficulty to improve accuracy of gear dimension compare to another products is the dimension accuracy is very high, approximately 10$\mu\textrm{m}$, and because die of involute teeth and elastic strain of forged tool differ from standard curve. This paper represent quantitative analysis of die and teeth of forged tool, namely difference of curves, with experiments and analyze the factor of dimension gap, finally, will design compensated involute curve.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.6
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• pp.47-54
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• 2008

Fitting process carried out in the automobile transmission assembly line is classified into three classes; heat fitting, press fitting, and their combined fitting. Heat fitting is a method that heats gear to a suitable range under the tempering temperature and squeezes it toward the outer diameter of shaft. Its stress depends on the yield strength of gear. Press fitting is a method that generally squeezes gear toward that of shaft at room temperature by a press. Another method heats warmly gear and safely squeezes it toward that of shaft. Warm shrink fitting process for the automobile transmission part is now gradually increased, but the parts (shaft/gear) assembled by this process produced dimensional changes in both the outer diameter and profile of the gear. So that it may cause noise and vibration between gears. In order to solve these problems, we need an analysis of warm shrink fitting process, in which design parameters are involved; contact pressure according to fitting interference between outer diameter of shaft and inner diameter of gear, fitting temperature, and profile tolerance of gear. In this study, an closed form equation to predict contact pressure and fitting load was proposed in order to develop an optimization technique of the warm shrink fitting process and verified its reliability through the experimental results measured in the field and FEM, that is, thermal-structural coupled field analysis. Actual loads measured in the field was in good agreements with the results obtained by the theoretical and finite element analysis.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.29 no.2
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• pp.117-123
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• 1993

In order to analysis the tensile properties of the high-tech fibers for fishing gear materials. tensile strength was tested on raw materials, single yarns and netting twines(plied yarns)made of nylon, kevlar 29 and techmilon respectively. The results obtained are as follows: 1. The tensile stress and tenacity of unknotted single yarns in dry and wet conditions were 3 to 3.5 times greater in the high-tech fibers than in nylon. But the elongation of the high-tech fibers was about 15% of that in nylon. 2. The tensile strength of knotted single yarns in dry and wet conditions was arranged in order of as follows : techmilon. kelver 29, and nylon. The ratio of knot strength to tensile strength, knot efficiency, was the highest in nylon. 3. The tensile strength of unknotted netting twines in dry and wet conditions was 2.3 to 2.5 times greater in the high-tech fibers than in nylon. 4. The tensile strength of knotted netting twines in dry and wet conditions was arranged in order of as follows : techmilon, kevlar 29, nylon. The knot efficiency was the highest in nylon.