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김성윤(SㆍYㆍKim),김유택(YㆍTㆍKim),남청도(CㆍDㆍNam),이영호(YㆍHㆍLee),강호근(HㆍKㆍKang),김성동(SㆍDㆍKim) 한국마린엔지니어링학회 2005 한국마린엔지니어링학회 학술대회 논문집 Vol.2005 No.-
The effect of break down of centrifugal pump due to entrained air has not been clarified yet. Thus, air-water two-phase flow experimental apparatus was installed to clarify the effect of break down. The performance results of a single-phase flow satisfied reappearance. Also, the heads coincided well impeller types.
Conceptual Design on a Direct-Operated Relief Valve with High-Precision and Large-Flow
S. D. Kim(김성동),J. H. Kim(김준현) 유공압건설기계학회 2021 유공압건설기계학회 학술대회논문집 Vol.2021 No.11
Conventional direct-acting relief valves have a few critical disadvantages. The three known disadvantages are the low pressure precision, the low allowable flow rate, and unstable chattering phenomena. In this research, design concepts are presented to improve the above mentioned disadvantages. Four key design concepts are applied in a direct-operated relief valve to achieve high pressure precision, large flow, and less chatter. The design concepts consist of poppet-opening flow-force configuration to balance the pressure force with spring force, a variable-elasticity spring to match the spring elasticity to the flow-force elasticity, a stabilization damper to achieve anti-chattering property, and a pilot piston that has small pressurizing area. The poppet-opening flow-force and the variable-elasticity spring are used to reduce the pressure override from the cracking pressure. The pilot piston with small pressurizing area helps to reduce the load force actuated on the spring and makes it possible to reduce the diameter of spring wire. Figure 1 shows the relief valve configuration to which these design concepts are applied. Figure 2 shows the flow-pressure performance of the valve which was calculated via a computer simulation. Figure 3 shows the stable response of pressure. This study presented only the conceptual ideas, and the process of designing and manufacturing prototype valves. The performance of prototype valves will be tested in the future.
에너지보존과 토크평형을 이용한 제로터 유압 펌프/모터의 배제용적 해석
김성동(S. D. Kim),김대명(D. M. Kim),함영복(Y. B. Ham) 유공압건설기계학회 2013 드라이브·컨트롤 Vol.10 No.2
It is difficult to analytically derive a volumetric displacement formula of gerotor hydraulic pump/motor because geometric shape of rotors is complicated. An analytical method about the volumetric displacement is proposed in this work, which is relatively easy and based upon two physical concepts. The first one is energy conservation between hydraulic energy of the pump/motor and mechanical input/output energy. The second concept is torque equilibrium with respect to inner and outer rotors. The formula about the volumetric displacement is derived for the common case of inner and outer rotors rotate with respect to fixed axes. The formula is verified by comparing another analytical displacement formula, and it is numerically verified by comparing numerical results, which is calculated for geometric specification of a motor. The numerical displacement is calculated through CAD software program and MATLAB program. The proposed analytical formula can be utilized in analysis and design of hydraulic gerotor motors.
회전날개 길이를 이용한 제로터 펌프의 용량에 관한 연구
김성동(S. D. Kim),김대명(D. M. Kim),구지석(J. S. Gu),오성진(S. J. Oh),함영복(Y. B. Ham) 유공압건설기계학회 2010 유공압건설기계학회 학술대회논문집 Vol.2010 No.10
It is hard and complex to analytically derive a formula for the volumetric-displacement of a Gerotor pump. An analytical method on the simple formula for calculating volumetric-displacement of a Gerotor pump is proposed in this work, which is relative easy and based upon using length of rotary teeth. The rotary teeth lengths mean the distances from axis of inner rotor or outer rotor to conatact points between inner and outer rotors. The proposed formula is verified through comparison with volumetric-displacement obtained from numerical CAD calculation.
가변주파수 신호를 이용한 서보 밸브 동특성 시험에 관한 연구
김성동(S.D. Kim),전세형(S.H. Jeon),진광호(K.H. Jin) 유공압건설기계학회 2014 유공압건설기계학회 학술대회논문집 Vol.2014 No.4
Signals of flowrate and spool displacement have been used to diagnose the dynamic performance of hydraulic servovalve. however, it is hand to measure a dynamic flowrate signal which rapidly varies in a short time period. Most of servovalves do not have a bwilt-in sensors for spool displacement. In the work, it was studied to use pressure signal to diagnose servovalve’s dynamic performance instead of the flowrate and displacement signals, The bandwidth frequencies to represent the dynamic properly of servovalves were measured from an experimental set-up. The bandwidth frequencies of load pressure for current input signal were compared with those of spool displacement.