• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.479-483
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• 1987

The reducers are widely used to reduce output speed and to amplify driving torque of actuator for industrial robots and many industrial units. But the vibration of robot, which is affected by the reducer, becomes a problem for robot which has to move a driven part with high accuracy. This paper compares experimentally the vibration characteristics of the reducer for industrial robot.

• Journal of the Korean Society for Precision Engineering
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• v.5 no.3
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• pp.81-90
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• 1988

In recent, the requirement of remote control of hychaulic system is in- creasing. The actuator unit whose output position is proportional to input electrical signal needs a pressure reducer and a dump valve. The pressure reducer provides a constant regulated pressure and filters contaminants. The dump valve supplies proper pressure to the pressure reducer and unloads when the system is not operated. In this thesis, dump valve and pressure reducer with auxiliary function are studied. The choke in the pressure reducer prevents actuator from supplying higher pressure than necessary pressure at beginning, and the spring constant affects on the dynamic characterisics. In dump valve, it is proved that diameter of servo-slide hold and choke diameter of dump plunger affects on damping response.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.7
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• pp.599-604
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• 2012

In this study, the safety of the driving gear reducer of ESW(essential service water) traveling sea water screen was evaluated through seismic analysis. Mode analysis of gear reducer was performed for reliability of analysis. Seismic analysis was performed in operating basis earthquake(OBE) and safe shutdown earthquake(SSE), which were applied as design condition using floor response spectrum( FRS). The maximum strain of gear reducer under OBE and SSE were 20.4 ${\mu}$ and 33.6 ${\mu}$, respectively. The maximum stresses were 2.42 MPa under OBE condition and 4.36 MPa under SSE condition, which were smaller than the allowable strength of material.

• Journal of Biosystems Engineering
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• v.22 no.4
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• pp.497-502
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• 1997

Automation facilities of greenhouses have been continuously developed. However, the conventional two-stage worm gear reducer reveals some problems, including low transmission efficiency. The worm gear reducer also have some difficulties in manufacturing and short life. Therefore, this study was performed to develop a planetary gear reducer, having a high Sear reduction ratio and high torque transmission efficiency. The planetary gear system consisted of a fixed ring gear and a 2-teeth differential ring gear turning slow, as the planetary pinion orbits fast around the fixed ring gear. The developed gear system can achieve a high speed reduction rate at one stage. The reducing system was employed to the greenhouse ventilation system. The reducer has the transmission efficiency of 70.5%, 2∼3 times longer life time, and twofold roll-up torque at an affordable price, comparing with conventional reducers. This reducer can be also applied to many industrial equipments, such as industrial crane, hoist, elevator and gondola etc.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.11a
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• pp.289-295
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• 1999

A new conceptual wave rolling ball reducer was proposed and investigated. The main components of the reducer were a eccentric input shaft and bearings, followers with balls, a flange, and a outer ring with waved groove. Followers moved along the holes of the flange according to the rotation of the shaft. And the balls installed in tips of followers were rolled with the waved groove of outer ring. When the shaft was rotated as one revolution and the outer ring was fixed, the flange was rotated as one wave. The kinematic analysis of the reducer carried out. The forces of each components were estimated, and the main design parameters were investigated. The design program using Visual C++ and Auto Lisp to determine the design parameters and to generate the drawing sheet.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.3
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• pp.63-68
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• 2017

In order to process more complicated and higher-precision parts, generally, an additional axis for a machine tool is needed which was an approach to minimize the cost of tool modification. A table with a rotary reducer that can rotate through the axis of the gear system was employed to a machine tool to achieve the purpose of adding an extra motion axis. In general, the motion of the rotary reducer is driven by a worm/wheel or helical gear system, which is different from the hypoid helical gear structure that used in this research. Reliability of guarantee of high accurancy throughout the whole life cycle is on of the critical factors to evaluate a rotary reducer in this field. In this paper, in order to evaluate life-time of rotary reducer, a low-cost accelerated life test was developed to satisfy the demands of clients.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.6
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• pp.732-737
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• 2011

The planetary gear reducer becomes more and more widely used in machine industries. The planetary gear reducer has a significant role to transmit power to wheel & tire module in the In-wheel system. Thus, the planetary gear reducer should have strong stiffness and durability. In this paper, the contact and bending stresses at the tooth of the planetary gear reducer are analyzed using MASTA, a commercial gear design and analysis software. Stress distribution at the tooth face of the sun, planetary and annulus gears are obtained using the finite element method. The design modification is performed using the response surface method. The usefulness of the design modification and optimization method presented in this paper is verified by comparing the maximum stresses of the original and optimized planetary gear tooth.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.62.2-62.2
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• 2010

The CQUEAN (Camera for QUasars in EArly uNiverse) is an optical CCD camera optimized for the observation of high redshift QSOs to understand the nature of early universe. The focal reducer, which is composed of four spherical lens, is allowed to secure a wider field of view for CQUEAN, by reducing the focal length of the system by one third. We designed the lens configuration, the lens barrel, and the adapters to assemble to attach focal reducer to the CCD camera system. We performed tolerance analysis using ZEMAX. The manufacturing of the focal reducer system and its lab test of optical performance were already finished. It turned out that the performance can meet the original requirement, with the aberration and alignment error taken into account. We successfully attached the focal reducer and CQUEAN to the cassegrain focus of 2.1m telescope at McDonald Observatory, USA, and several tests of CQUEAN system were carried out. In this presentation, I will show the process of focal reducer fabrication and the result of performance test.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.46-47
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• 2018

High performance concrete with low water-to-cement ratio has been widely used with increased demand of high rising buildings and huge scaled structures. Additionally, for high performance concrete, various SCMs are replaced to improve its performance from fresh state to hardened state. With the drawback of increased viscosity of the concrete mixture for high performance concrete, low-viscosity typed high range water reducer is the relatively new admixture. Therefore, as a goal of the research, under using various SCMs with wide range of content, the performance of low-viscosity typed high range water reducer was evaluated. Especially, in this research, the influence of low-viscosity typed high range water reducer on rheological properties including plastic viscosity and yield stress were assessed. As a result of the research, it is expected to provide a fundamental information of low -viscosity typed high ranged water reducer on high performance concrete with various conditions of SCMs.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.11
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• pp.1399-1406
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• 2011

The reducer of the mixer is one of the main parts of the processor used for water and wastewater treatment. In this study, an advanced reducer with a drywell structure was developed in order to prevent oil leakage during operation in the field. During the development of the advanced reducer prototype, a mockup, a metal mold, and a cast were made using CAD and a CNC machine. The structural safety of the reducer prototype's lower housing (drywell structure) was checked using the ALGOR commercial FEM analysis code, which yielded a von Mises stress of about 123 N/mm2, which is below the yield stress of 250 N/$mm^2$, and a natural frequency of about 650-700 Hz. In addition, the torque transmission efficiency for the advanced prototype was 95.87%, which is about 8% more than that found in a previous study, 88.45%, and the sound level was below 75 dB. Furthermore, no oil leakage or abnormal sound or vibration occurred. Therefore, an optimally designed advanced reducer prototype has been successfully developed.