• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1576-1580
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• 2007

Typical lip seals are widely used as sealing mechanism of rotary and reciprocating shaft. Double lip seal has comparatively high stiffness and dynamic radial eccentricity. Usually material of these seals is made of elastomer and nonlinear finite element analysis is required to analyze behaviour of this material because Young's modulus is varied with working load. In this paper, MSC MARC/MENTAT is used for nonlinear analysis of double lip seal with pressure variation and interference. The contact normal force of double lip seal between lip and shaft is analyzed to reduce power loss when shaft rotates.

• Tribology and Lubricants
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• 제35권4호
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• pp.215-221
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• 2019

A gerotor set consists of two elements, an inner rotor and an outer rotor. The outer rotor has one more tooth than the inner rotor and has its centerline positioned at a fixed eccentricity from the centerline of the inner rotor. Although gerotors come in a variety of geometric configurations, all gerotor sets share the basic principle of having generated tooth profiles that provide continuous tight sealing during operation. The size of the gerotor is proportional to the number of teeth and the amount of eccentricity. The interior of an inner rotor with a large number of teeth has an enough space to include other machine elements. In this paper, the double gerotor mechanism, constructed by putting a small gerotor in the interior of a large inner rotor, is conceptualized. The double gerotor set is composed of an inner rotor, a planetary rotor, and an outer rotor. The inside profile of the planetary rotor corresponds to the outer rotor profile of the small gerotor, and the outside profile is the inner rotor profile of the large gerotor. In the double gerotor, the centers of the inner and the outer rotor are coincident because the eccentricities of two gerotors are balanced. The operation of a double gerotor is examined by analyzing the planetary motion, and a feasibility study for application of the double gerotor for hydraulic motors and pumps is performed. The double gerotor set has much application potential as a component of hydraulic systems.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2000년도 학술대회논문집
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• pp.225-230
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• 2000

This paper describes a double-ended current fed push-pull type high frequency resonant inverter used as the power supply for wax-sealing. The proposed inverter can realize ZVS operation by using resonant capacitor to ZVS capacitor and has some merits not only reduction of switch current distribution but also extension of load range compare to the conventional single-ended current fed push-pull type high frequency resonant inverter. This analysis of proposed circuit uses normalized parameter ad characteristic estimation which is needed in each step before design is generally described according to normalized frequency($\mu$), normalized resistance(λ) and parameters. It is also presented as an example of method of the circuit design based on estimation analysis values from theoretical analysis. The theoretical analysis is proved through experiment and this circuit shows that it can be used practically as the power supply system for wax-sealing and DC-DC converter.

• Tribology and Lubricants
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• 제19권1호
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• pp.9-14
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• 2003

The sealing performance of an elastomeric O-ring using the double layered material has been analyzed fer the contact stress behaviors that develop between the O-ring seal and the surfaces with which it comes into contact. The leakage of an O-ring will occur when the pressure differential across the seal Just exceeds the initial (or static) peak contact stress. The contact stress behaviors that develop in compressed O-rings, in common case of dovetail grooved geometry, are investigated using the finite element method. The FE analysis includes material hyperelasticity and axisymmetry. The computed FEM results show that the contact stress behaviors are related to the ratio of diameter between the inner ring and the outer ring, and the temperature of vacuum chamber.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 춘계학술대회 논문집
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• pp.239-244
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• 2001

Hot hydrostatic extruder was developed. The main objective of the development is forming fine wire and tube. On account of effectiveness and high performance, the extruder was designed to have double action. Therefore the main cylinder and mandrel can be driven independently. To cope with severe condition of high temperature and pressure, wire-wound container equipped with heater was used. Sealing technique also is important in this process, so seal ring was made of super-elastic metal. Another key for successful forming is choice of proper pressure medium. Fine wire and tube produced by the extruder can be used in semiconductor industry and medicine.

• 한국표면공학회지
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• 제54권1호
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• pp.30-36
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• 2021

In this study, double-layered anodizing films were formed on Al 5052 and Al 6061 alloys consecutively first in sulfuric acid and then in oxalic acid, and hardness, withstand voltage, surface roughness and acid resistance of the anodizing films were compared with single-layered anodizing films in sulfuric acid and oxalic acid electrolytes. Hardness of the double-layered anodizing film decreased with increasing ratio of inner layer to outer layer for both Al 5052 and Al 6061 alloys, suggesting that outer anodizing film formed in sulfuric acid electrolyte is damaged during the second anodizing in oxalic acid electrolyte. Withstand voltage of the double-layered anodizing films increased with increasing the thickness ratio of inner layer to outer layer. Surface roughness of the double-layered anodizing films were comparable with that of single-layered anodizing film formed in sulfuric acid but higher than that of single layer anodizing film formed in oxalic acid electrolyte. In acid resistance test, all of the double-layered and single-layered anodizing films showed good acid resistance more than 3 h without any visible gas evolution, which is attributable to sealing of pores. Based on the experimental results obtained in this work, it is possible to design a double-layered anodizing film with cost-effectiveness and improved physical and electrical properties by combining two consecutive anodizing processes of sulfuric acid anodizing and oxalic acid anodizing methods.

• 대한기계학회논문집
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• 제17권5호
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• pp.1150-1160
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• 1993

본 연구에서는 보압과정시 급속한 압력구배에 의한 관성항의 영향을 고려하기 위해 수정된 Hele-Shaw 모델과 압축열 발생항, 온도와 압력의 변화에 따른 수지의 밀 도 이완현상에 대한 모델의 도입 및 유한요소법을 이용한 수치해석적 방법을 제시하여 정확한 잔류압력을 구하고 성형조건 및 물성치에 따른 수지의 거동을 살펴보고자 한다.

• 한국생산제조학회지
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• 제18권4호
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• pp.436-441
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• 2009

An air filter is a device to remove dust from the air supplied to the automotive engine. A requirement for the optimum air filter is to improve the capability to remove particles from the air it takes in, that is the efficiency and amount of dust collection. By removing dust from the air, the air filter prevents the engine cylinder from wear, reduces ventilation resistance, and thus improves engine output and guarantees intake performance. In order to guarantee such air filter performance, it is very important to properly seal the air filter. For passenger cars made in Korea, the air filters are fabricated with steel caps as their frames are large and their engine capacity is big. Recently however, European countries and Japan started using urethane for manufacturing the air filter, so that all foreign-made cars now have urethane filters. The urethanes used for air filters are applied in two ways: One is to use soft urethane for both top and bottom of the air filter and the other is to use soft urethane for the top and hard urethane for the bottom. Each of these method has unique problems. In this study, hard urethane is used for both top and bottom of the filter in order to improve those problems and increase the sealing efficiency. Especially for the top, NBR (rubber mold) is pre-settled in tough urethane and then the urethane is solidified through foaming, which makes it possible to develop a solid and double-sealed filter.

• 한국초전도ㆍ저온공학회논문지
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• 제13권1호
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• pp.51-55
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• 2011

In this study, the liquid-vapor (L-V) separator equipped with liquid-level meter is developed. In the developed L-V separator, the flange is designed to be attachable so that the separator can be flexibly applied under any cases where the volumetric of L-V separator is varied by the system requirement. The leak-tightness between the attachable flange and the chamber is experimentally confirmed with the use of double groove indium wire sealing even under the high pressure up to 20 bar. In addition, the liquid-level meter is designed and fabricated to figure out the inner state of L-V separator. It consists with 19 carbon composition resistors in series. All resistors are separately calibrated in the temperature range from 77 K to 200 K. The performance of the L-V separator and the liquid-level meter is investigated with experimental tests, and the result is presented in this paper.

• 멤브레인
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• 제21권4호
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• pp.321-328
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• 2011

$PrBa_{0.9}Sr_{0.1}Co_2O_{5+{\delta}}$ 조성의 산화물을 고상반응법을 이용하여 합성하였다. 합성된 분말은 압축 성형 후 $1,250^{\circ}C$에서 소결하여 치밀한 세라믹 분리막을 제조하였다. 제조된 $PrBa_{0.9}Sr_{0.1}Co_2O_{5+{\delta}}$분리막은 XRD분석 결과 이중 페롭스카이트 (double perovskite)구조를 보였다. 밀봉재료로는 pyrex ring을 사용하여 가스누출 실험 및 산소투과 분석을 하였다. 산소투과량 분석은 $850{\sim}950^{\circ}C$범위에서 측정되었다. 산소투과실험 결과, 투과량은 온도증가에 따라 0.15에서 $0.32mL/cm^2{\cdot}min$로 증가하였다.