• Journal of Convergence for Information Technology
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• v.12 no.2
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• pp.142-148
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• 2022

In this paper, the weight reduction design of the yaw gearbox for wind turbine was performed through the finite element analysis method, and the stability was checked by performing the critical speed analysis. The weight reduction product can improve engine efficiency, save parts materials, and earn economic benefits. The yaw gearbox is lightweighted with the goal of achieving a safety rate of 1.3 or higher for wind turbine as indicated by IEC61400-1. In order to reduce the weight of the carrier, a topology optimization method was performed. The safety factor was verified by performing finite element analysis on the carrier. In addition, the housing and carrier were modeled using the finite element method, and the gear train was modeled using MASTA. For the yaw gearbox, the housing and carrier FE model and the gear train model were connected by the partial structural synthesis method to perform the rotational vibration analysis. Vibration excitation sources are mass unbalance and gear mesh frrequemcy, and as a result of the critical speed analysis, it was found that there was no resonance within the operating speed range.

• Journal of Power System Engineering
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• v.21 no.4
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• pp.77-83
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• 2017

The aim of this paper is to solve the chattering and delayed response problems caused by gear backlash. In the gear mechanism based systems, for example, in robot systems, the actuators provide the reduction gear with motors to transfer effectively electric power to mechanical power. Therefore, the gear backlash exists and is an unavoidable fact which makes many undesirable problems. In this paper, the authors try to make a solution for this issue and, introduce several control methods which are PID only, PID with Smith predictor and super-twisting algorithm based SMC(sliding mode control). Each control method is applied to the real plant in which strong backlash is included. By comparison results, it is clear that SMC gives the best control performance with little backlash effects. Also, the usefulness and effectiveness of proposed control method is verified by experiment.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.9
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• pp.21-27
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• 2022

The rotorcraft engine gearbox transmits the power generated by the turboshaft engine to the rotor by reducing the rotational speed and increasing the torque. The core of the rotorcraft engine gearbox is lightweight performance, which requires maximum weight reduction within the range that meets various requirements and constraints. Therefore, lightweight design through gear macro geometry optimization is necessary. In this study, gear macro geometry optimization was performed to reduce the weight of a rotorcraft engine gearbox. NSGA-III was used for the optimization, resulting in a combination of the gear ratio and macro geometry that minimizes the weight of the total gear. In addition, the safety factor of the gears satisfied the given conditions.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.8
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• pp.885-893
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• 2006

A dynamic model of turbo air compressor having multi-helical gear pairs is developed by transfer matrix method. The model accounts for the shaft and bearing flexibilities, gyroscopic effects and the force couplings among the transverse, torsion, and axial motions due to gearing. The program which can be used to analyze and predict the vibrational characteristics by the mass unbalance of the rotors and gear transmission error of turbo compressor is developed with this system model We expect this developed program to contribute the reduction of the vibration/noise on turbo compressor in the field of both design and manufacturing and can be used as a basic sub-program for CAD/CAM of low-noised gear teeth also.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.2
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• pp.223-230
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• 2003

Stress patterns are created in the plastic spur gear tooth body by introducing a hole or a steel pin to improve stress distribution. Static analysis using finite element method is carried out to show the effect. The result shows that maximum stress as well as tooth tip displacement is dependent on the size and location of a hole or a steel pin. When a hole located on the tooth center line, the maximum static stress level and the tooth tip deflection is always higher than that of a solid gear. But, a considerable reduction in the maximum stress and tooth tip displacement is achieved by insertion of steel pin.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.6
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• pp.1312-1319
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• 1988

Internal gear is the important part of the planetary reduction gear system. This study aims at developing the numerical analysis method for design of spherical hob to manufacture internal gear. Methods of calculation of hob tooth profile, generating tooth profile and tooth profile errors such as the errors of pressure angle, tooth thickness and pitch of spherical hob must be made smaller than those of standard tooth profile. And, the smaller the pressure angle and the number of equivalent pinion tooth become, the larger the tooth profile errors are. One design example of spherical hob is proposed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.158-161
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• 2005

In this paper, the precision electric discharge machining technology, the powder electric discharge machining technology, is applied to making a cold forging die for making the helical type of clutch gear. Various working conditions are investigated with emphasis on reduction of the electrode wear and enhancement of the surface roughness. Through the research work, the key technology of making the helical gear forging dies is achieved.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.249-252
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• 2006

Wind turbine gearbox is a complex mechanical system that includes gear trains, shafts, bearings, and gearbox housings. All these component are interacting with each other therefore changing certain design parameter will affect other components. RomaxDesigner enables a reduction in development period by simulating the full gearbox system. The gear pairs, bearings and shafts are represented as analysis objects and the complex components are modelled by means of reduced stiffness matrices. The software allows durability analysis and advanced contact analysis including the effects of system misalignments in gear and bearing. In this paper the 2MW wind turbine gearbox was model led and a study on optimum design was conducted

• Journal of Institute of Convergence Technology
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• v.13 no.1
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• pp.7-12
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• 2023

The built-in motor with an integrated magnetic gear can realize high torque without a separate reduction device. In this paper, the main design parameters of the magnetic gear constituting the magnetic geared motor are derived and the sensitivity analysis results according to these design parameters are discussed. In particular, processing and assembly issues of modulators sandwiched between rotating bodies are discussed, and loss and magnetic force characteristics of various types of modulators are introduced. Since the modulator, which plays a key role in converting the torque of the magnetic gear, is desirable to have a separate form, it is inevitable to add a non-magnetic support to add torsional stiffness according to high-speed rotation, so the effect of this is also analyzed.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.6
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• pp.631-637
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• 2013

The characteristics of involute gear pump with eccentric gap between gear tip and housing have been studied in terms of volumetric flow rate and/or flow efficiency. The analysis has been done with FLUENT/R-13 employing with k-e model for the turbulent flow under the given conditions of rotational velocity, gap distance and outlet pressure. The effect of parameters continues to be shown for the eccentric gear as same as for the concentric gear such that the volumetric flow rate (volumetric efficiency) increases as the increases of rotational velocity and decrease of gap distance and of outlet pressure. In the meantime, the shape of pressure build-up appears to be exponentially increase as gap distance decreases at upstream position. The pressure is rapidly developing in the upstream and remains almost constant thereafter in the downstream of circumferential flow path. This typical characteristics becomes more profound as eccentricity increases. The pump performance for the eccentric gear pump with minimum gap distance shows better than its concentric counterpart. However, it shows not for the concentric pump with minimum gap distance. Therefore, the gap reduction due to eccentricity may be positive for pump performance.