• Tribology and Lubricants
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• v.3 no.2
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• pp.72-80
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• 1987

A planocentric torque driver comprises a stationary internal gear with the teeth of a circular concave profile and an external gear of an epitrochoid curve. The contact mechanism of the teeth is examined and analyzed by means of computer simulation. Analyses of load variation on the tooth and strength of appliance is carried out. And the output device is examined. Finally, the design of a 59:1 reduction ratio torque driver is presented.

• Tribology and Lubricants
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• v.4 no.2
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• pp.60-67
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• 1988

Conventional theory of gear mechanism can't be applied to analyze the harmonic drive due to specific movement of the teeth. This paper deals with an analysis of kinematics and geometry of the tooth engagement of a harmonic drive comprising circular spline, flexspline and wave generator. A theoretical new tooth profile of the flexspline in meshing internal rigid gear with involute profile is obtained. Characteristics of harmonic drive reducer are shown according to parameters such as deviation coefficient, deviation distance, addendum modification coefficient. As an example, the design of harmonic drive with 1:80 reduction ratio is presented.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.6_3
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• pp.1223-1231
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• 2023

In the case of internal combustion engine vehicles, transmissions are essential for various reasons, such as vehicle starting and speed control. However, in the case of electric vehicles, unlike internal combustion engine vehicles, a transmission is not necessarily required. Of course, considering the efficiency of electric vehicles, a transmission is necessary, but installing the existing transmission as is has the opposite effect due to increased vehicle weight, so it has not been considered so far. In this paper, a non-contact reducer type using the Arago disc effect is proposed rather than a transmission using a conventional gear train, and the aim is to examine whether this can increase the driving efficiency of electric vehicles while minimizing weight. In addition, the effectiveness of the proposed reducer will be verified by manufacturing and testing it.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.4
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• pp.344-349
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• 2009

To improve performance of the main landing gear for helicopters, a semi-active control landing gear is introduced in this paper. An MR damper based on commercial finite element electromagnetic field analysis of an electromagnet has been adapted the shock absorber. Force control algorithm (which maintains constantly the sum of air spring force and damping force as internal forces) which keep the sum of air spring force and damping force constant during landing, has been used for the controller, applied to control the semi-active landing gear. A series of drop simulations using ADAMS has been done with the passive, sky-hook control type, and force control type landing gears. The result of each simulation has been compared to evaluate the landing performance of the proposed force control type landing gear.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.3
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• pp.83-89
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• 2000

In hydraulic control system turbine and gear motor type flowmeters are widely used to measure the flow rate under steady flow conditions. With the recent growth of interest in the measurement of instantaneous values of unsteady flow rate the test of the transient response of these flowmeters are in some significance. however an unsteady flow rate mea-surment and its calibration method with a fast response and a high accuracy have not beendeveloped. In this research particularly the dynamic characteristics of turbine and gear motor type flowmeters are investigated experimentally and simple mathematical models are proposed. The measured flow rate waveforms are compared with those by remote instan-taneous flow rate measurement method(RIFM) which has been developed by author and used for calibration As the result of frequency response test gain and phase between the measured flow rate waveforms by turbine type flowmeter and those estimated by RIFM are in good agreement up to 70Hz For the gear motor type flowmeter th simulated results by a math-ematical model proposed here agree well with the experiment nearly up to 100Hz. Also it if sound that the pressure drop across the flowmeter is increased in proportion to the frequency of the flow rate variation in a high frequency region of more than 100Hz. It can be explained that the dealy of gear motor type flowmeter in high frequency regionis mainly attributed to a first order delay consisting of the inertia of gears and internal leakage of the gear motor.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.571-582
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• 2010

Typically nondestructive inspection methods of the large gear units are applied to penetrate non-destructive inspection. Nondestructive penetrating inspection put into the small openings of the defect to penetration liquid, remove to excess penetration liquid on the surface of the gear units, spread with developing solution and we can find the small defect by coating with penetration liquid. However, this method has so many issues because of penetrate nondestructive tests on the gear assembly. The steep angle of screw is hard to achieved full penetration and has the problem to remove the excess. In contrast, the magnetic nondestructive inspection is easy to detect subsurface defects and subtle defects. According to the inspection results the stress concentrates in gear surface, some internal defects and microscopic flaws exist on the gear units are not found to penetrate the nondestructive inspection, but magnetic nondestructive inspection could have found many defect. Therefore, a reasonable method of nondestructive inspection for the large gear units is suitable to magnetic nondestructive inspection.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.3
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• pp.30-38
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• 2015

As products using LEDs are developed actively, also there has been large request for LED products that can replace traditional lamps like fluorescent lamps and metal halide lamps. But so far there is no proper standard that manufacturer can use and test it. As a result manufacturer can't develop retrofit LED lamps and sell it even they have technology. In this study, by analyzing control gear for fluorescent lamp that is currently used in market which is magnetic or electronic ballast, I'd like to develop proper test method by investigating compatibility between all-type control gear and LED retrofit products.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.45 no.4
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• pp.276-286
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• 2009

The main purpose of this research is to analyze economic feasibility of biodegradable sonw crab gill net model project. The results of benefit/cost analysis show that use of the biodegradable gear is economically feasible. Assuming that the rate of gill net lost is 5 percent, net present value was estimated 311,898,282-590,533,375won, benefit-cost ratio 1.816-1.923 and internal rate of return 7.96-10.59%. The development and diffusion of biodegradable fishing gear appear to make a significant contribution to fisheries resource conservation and marine ecosystem protection. In addition, biodegradable gear production firms may have a good opportunity of exporting it to other coastal states, depending on the progress of WTO subsidy negotiation.

• Journal of Korea Foundry Society
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• v.24 no.6
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• pp.347-355
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• 2004

In the die casting process, the flow of liquid metal has significant influence on the quality of casting products and die life. For the optimal process design of automobile gear housing, various analyses were performed in this study by using computer simulation code, MAGMAsoft. The simulation has been focused on the molten metal behaviors during the mold filling and solidification stages for the sound casting products. Also the internal defects were predicted by application of air pressure and feeding criteria.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.3
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• pp.295-302
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• 2014

An internal gear pump is required to improve the flow rate and noise. Furthermore, such pumps are durable and small in size. In this study, equations of the rotor shape with multiple profiles (ellipse 1-involute-ellipse 2) were derived, and relevant performance parameters (pressure angle, irregularity, and specific sliding) of the internal gear pump to noise were predicted and compared. Rotor profiles and performance parameters were obtained by a prediction algorithm for theoretical analysis, and the effects between the design parameters and the performance parameters were analyzed. Based on the analysis results of the effects, an optimal design of the rotor profile was proposed, and a noise test of the prototype was performed to evaluate the reliability of the design.