• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.4
• /
• pp.7-14
• /
• 1998

Noncircular gears have been used for obtaining the modified anglualr velocity ratio between parallel axes. The elliptical gear, which is a kind of noncircular gears, makes use of ellipse as a pitch curve, and is applied for the measurement of the discharge of liquid. The applications of an elliptical gear are more advantageous than any other mechanism as like a crank-slider linkage or a cam mechanism in view of the accuracy and the reliability to transmit the prescribed motion. In this paper, acceding to the theoretical involute tooth profile, two pairs of the elliptical gears were manufactured by using CNC wire electronic discharge machine. The proper ranges of the operating pressure angle and of module not to generate under cutting are studied on the change of the eccentricity, because it is the eccentricity of the pitch curve that determines most of the characteristics of the elliptical gear and then the vibration analysis is executed for the verification of harmonious rotating.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2001.02a
• /
• pp.104-107
• /
• 2001

Racetrack coils are used in many areas of superconductivity applications such as generators, motors, maglev, wiggler magnets and so on. Especially now a days a few advanced nations including U.S., Japan are developing high temperature superconducting(HTS) wire which has better performance than low temperature superconducting(LTS) wire. Most of HTS wires such as BSCCO-2223 are manufactured with PIT(Power In Tube) process, so the shape of the wire looks like tape different from LTS wire with round cross-sectional appearance like normal conductors. Generally HTS racetrack coils are composed of a few partial double-pancake colis and then the double-pancakes are jointed each other according to their applications.

• 한국정보통신설비학회:학술대회논문집
• /
• 2003.08a
• /
• pp.367-372
• /
• 2003

도심의 편리한 생활을 위해 초고속 데이터 통신, 상하수도, 가스등의 원할 한 공급이 요구되고 있으며 이러한 인프라 시설들은 지하터널을 통하여 공급이 되게 된다. 도심지의 교통혼잡과 소음, 진동으로 인한 사회비용의 증가와 민원으로 사실상 개착식 공법은 적용되기 어려운 실정에 있다. 특히 앞에 열거한 인프라 시설들은 2m이하의 중소형 크기로 마이크로터널링 공법이 널리 사용되고 있으며 최근에는 현실적인 현장의 요구와 공사비용의 절감을 위해 1m이하의 소형터널에 대한 요구가 늘어 나고 있으나 마이크로터널링 머신의 소형화에 따른 절삭력의 감소와 지하 장애물에 대한 대처가 어려워짐으로 이에 대한 해결책이 요구되고 있다. 이를 위해 워터젯이 장착된 마이크로터널링 머신이 소개된바 있지만 면판에 단순고정된 형태라 절삭면적 및 효율에 한계가 있다. 본 연구는 절삭면적의 확대 및 효율의 증가를 위해 공전하는 면판에 자전하는 워터젯 보조면판을 제안하였으며 워터젯에 가장 적합한 커터종류를 찾기 위해 절삭력을 고려한 성능계수를 제안하였다.

• Proceedings of the KIEE Conference
• /
• 2004.07d
• /
• pp.2347-2349
• /
• 2004

The iron loss in electric machines takes large part of machine losses and the reduction of iron loss brings the increase of the efficiency. In the rotating machines, however it is very difficult to calculate result because the measuring processes are very complex and laborious. As is well known, the relation between the flux density B and the magnetic field intensity H relation is not linear. For the iron loss, B and H must be measured and usually B becomes the reference wave(sine wave) and the following H is measured using H-coil. To make the B as sine wave, B is controlled by some devices. The error is controlled to become zero by the proposed algorithm which uses the bisection algorithm. The experiments are compared with the simulation results, and they show acceptable agreements.

• Proceedings of the KSME Conference
• /
• 2001.11a
• /
• pp.562-567
• /
• 2001

The number of required modes to provide accurate force information in a truncated model of a flexible structure is investigated. In the case of modal truncation of a distributed parameter system, the difference in convergence rates between displacements and forces is discussed. The residual flexibility, a term from past literature, is used to recapture some of the lost force information in a truncated model. This paper presents numerical and experimental results of a study where the residual flexibility is used in conjunction with a Kalman filter so that accurate force information may be obtained from a small set of displacement measurements with a reduced-order model. The motivation for this paper is to be able to obtain accurate information about unmeasurable dynamic reaction forces in a rotating machine for diagnostic and control purposes.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2003.10a
• /
• pp.164-169
• /
• 2003

The purpose of this study is to develop a practical image inspect ion system that could recognize it correctly, endowing flexibility to the productive field, although the same object for work will be changed in the size and rotated. In this experiment, it selected a fighter, rotating the direction from 30$^{\circ}$ to 45 simultaneously while changing the size from 1/4 to 1/16, as an object inspection without using another hardware for exclusive image processing. The invariant moments, Hu has suggested, was used as feature vector moment descriptor. As a result of the experiment, the image inspect ion system developed from this research was operated in real-time regardless of the chance of size and rotation for the object inspection, and it maintained the correspondent rates steadily above from 94％ to 96％. Accordingly, it is considered as the flexibility can be considerably endowed to the factory automat ion when the image inspect ion system developed from this research is applied to the product ive field.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2003.10a
• /
• pp.324-328
• /
• 2003

The Magnetoeheological fluid has the properties that it's viscosity has dramastic changed under some magnetic fields therefore, Magnetorhlogical fluids has been used for micro polishing of the micro part( for example, a aspherical surface in a micro lens). The polishing process may appears as follows. A part rotating on the spindle is brought into contact with an Magnetorhological finshing(MRF) fluids which is set in motion by the moving wall. In the region where the part and the MRF fulid ate brought into contact, the applied magnetic field creates the conditions necessary for the material removal from the part surface. The material removal takes place in a certain region contacting the surface of the part which can be called the polishing spot or zone. The polishing mechanism of the material removal in the contact zone is considered as a process governed by the particularities of the Bingham flow in the contact zone. Resonable calculated and experimental magnitudes of the material removal rate f3r glass polishing lends support the validity of the approach.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.114-118
• /
• 2001

HP Laser Interferometer Measurement System[HP5529A] is one of the most powerful equipment for measurement of the motion accuracy. The straightness measurement system of the HP5529A is composed of wollastone prism and reflector. In this system, straightness error is measured by relative lateral motion between prism and reflector. But rotating motion of prism or reflector as moving optic causes not real straightness error but additive straightness error. Especially unwanted straightness error as this becomes very large when reflector is used as moving optic and an interval between reflector and prism is distant. In this paper, the compensation method is proposed for removing additive error and experiment is carried out for theoretical verification.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.848-851
• /
• 2003

In this paper, a separating system for used CRT recycling is presented. Depend on manufacturer CRTs has small differences in dimension for the same model, but the dimensions of the panel are nearly same. To simplifying configuration of the system, we developed CRT fixing pallets for every model of CRT. The height of cutting position for every model of CRT will be same. The cutting machine has two rotating arm and use metal-bond type diamond cutting wheel. Instead of water, two vortex tube type air-coolers are used for the cooling of cutter. Workers in recycling factory are generally old people. Therefore, control program should be easy to use and operate. Thus we developed GUI with very simple interface.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.10 no.1
• /
• pp.56-61
• /
• 1986

Rotor dynamic response of pumps is greatly influenced by the nature of the hydraulic forces arising from wearing seal, balance drum and impeller, etc.. Therefore, rotor dynamic analysis should be conducted during the design stage in order to aleviate some of the vibrational problems which might occur during the operational life of pumps. Previsousely, the authors have proposed the method to obtain the dynamic seal coefficients of the annular plain seal, convergent and divergent tapered seals, parallel grooved seal, spiral grooved seal and annular stepped seal. On the basis of these results, this paper presents the investigated effect of seals on the stability behavior of a centrifugal pump. The results show the effects of seal geometry, pressure difference, clearance, length/diameter ratio, on stability behavior.