• 제목/요약/키워드: Valve Materials

검색결과 344건 처리시간 0.033초

Measurment of Fluid Film Thickness on The Valve Plate in Oil Hydraulic Axial Piston Pumps (Part II : Spherical Design Effects)

  • Kim Jong-Ki;Kim Hyoung-Eui;Lee Yong-Bum;Jung Jae-Youn;Oh Seok-Hyung
    • Journal of Mechanical Science and Technology
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    • 제19권2호
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    • pp.655-663
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    • 2005
  • Tribological characteristics in the sliding parts of oil hydraulic piston pumps are very important in increasing overall efficiency. In this study, the fluid film between the valve plate and the cylinder block was measured by using a gap sensor and the mercury-cell slip ring unit under real working conditions. To investigate the effect of the valve shape, we designed three valve plates each having a different shape. One of the valve plates was without bearing pad, another valve plate had bearing pad and the last valve plate was a spherical valve plate. It was noted that these three valve plates observed different aspects of the fluid film characteristics between the cylinder block and the valve plate. The leakage flow rates and the shaft torque were also investigated in order to clarify the performance difference between these three types of valve plates. From the results of this study, we found that the spherical valve plate estimated good fluid film patterns and good performance more than the other valve plates in oil hydraulic axial piston pumps.

벤더형 고응답 압전밸브의 주파수 특성에 관한 연구 (A Study on Frequency Characteristics of a Bender Type High-Speed Piezoelectric Pneumatic Valve)

  • 윤소남;함영복;박중호;이성수
    • 드라이브 ㆍ 컨트롤
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    • 제9권4호
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    • pp.14-18
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    • 2012
  • Two kinds of piezoelectric actuator are applied to the valve for controlling the direction, the flow and the pressure of the fluid. One is a stack type piezoelectric actuator which has very fast response characteristics but very tiny displacement. The other is a bender type piezoelectric actuator which has also fast response characteristics but lower than the stack type one, and has longer displacement than the stack type one. So, the bender type piezoelectric actuator has advantage to apply to the valve for controlling a large amount of flow and fast on-off operating. In this study, the bender type piezoelectric pneumatic valve for color sorter is designed and fabricated. The new type high speed piezo valve with the both side supporting mechanism for high operating frequency and high reliability is discussed for separating the foreign body from the grains. Finally, the performance characteristics of a fabricated valve are analyzed and the frequency characteristics are also discussed for substituting the conventional type solenoid actuator.

밸브 거동 특성 파악을 위한 hole 센서의 적용에 관한 실험적 연구 (The Experimental Study on Characteristics of Valve System using Hole Type Valve Lift Sensor)

  • 문건필;이용규;이승진;최교남;정동수;박성영
    • 한국자동차공학회논문집
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    • 제16권3호
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    • pp.80-86
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    • 2008
  • Recently, controlled auto ignition(CAI) in gasoline engines are drawing more attentions due to its extremely low level of NOx emissions and potentials in lowering the fuel consumption rate. The one of the key techniques for realizing CAI combustion in engines is the control of valve system. Since the valve linkage system with higher complexity, or even earn-less valve systems, such as electro-hydraulic and electro-magnetic system, are adopted in CAI engines, it is not easy to estimate the valve lift profile from earn profiles. Therefore new measurement techniques for valve lift in CAI engines have been tried and tested. In this paper, hole type valve lift sensor was developed and tested to check the applicability in CAI engines. The valve lifts could be obtained from the sensor signal, which depends on the distance from the sensor to magnet attached to valve. Various engine speeds, ranging from 2,000 to 6,000 rpm, and valve lifts, maximum up to 9.7 mm, were tested. It was found that the sensor output for valve lift had accuracy of 98% in comparison with the basic specifications of valve lift through improvements of sensor driving circuit.

극저온 선형 팽창기용 리드밸브의 기하학적 형상변화에 따른 유동 특성 연구 (A Study on the Flow Characteristics of Reed Valve with Variable Geometric Variations for Cryogenic Linear Expander)

  • 정은아;김지우;염한길;윤소남
    • 드라이브 ㆍ 컨트롤
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    • 제12권4호
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    • pp.48-53
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    • 2015
  • This paper deals with the flow characteristics of a reed valve analyzed using computational dynamics(CFD) for optimal design. The seat sizes of the valve are modeled asØ6[mm] and Ø8[mm] to compare the flow characteristics. The inlet boundary condition is entered at 10[kPa], 15[kPa], 20[kPa], and 30[kPa] and the outlet boundary condition is set to the atmospheric pressure. The flow coefficient(C) and pressure loss coefficient(K) are calculated from the results of flow analysis. From the analysis results, it was confirmed that the flow coefficient of a reed valve having a seat size of Ø6[mm] is greater than that having a seat size of Ø8[mm], and the coefficient of pressure loss of a valve with a seat size of Ø6[mm] is lower than the Ø8[mm] size valve.

비례솔레노이드 밸브의 해석을 위한 전후처리기에 대한 연구 (Research on Pre- and Post-Processor for Analysis of Proportional Solenoid Valve)

  • 윤동원;함상용;박중호;윤소남;김칠성
    • 대한기계학회논문집A
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    • 제36권8호
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    • pp.865-871
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    • 2012
  • 본 논문에서는 기존의 유한요소 프로그램을 이용하여 솔레노이드 밸브의 해석을 용이하게 하는 프로그램 개발에 대해서 다루었다. 비례솔레노이드 밸브에서 정확한 해를 얻기 위해서는 이론적인 식보다 기존의 유한요소 해석툴을 이용하는 것이 유리하며, 이때 사용자의 편의성을 위해서 솔레노이드의 형상을 삼각형, 사각형 등의 간단한 도형의 조합이라고 가정하여 모델링하도록 하였다. 이러한 가정을 사용하여 개발된 솔레노이드 해석 프로그램은 사용자가 솔레노이드의 유한요소 모델을 쉽게 생성할 수 있도록 해주었다. 개발된 프로그램의 유용성을 검증하기 위해 실제 솔레노이드 밸브에 대한 해석을 수행하였으며, 해석결과 개발된 프로그램은 솔레노이드 밸브의 비례특성을 잘 해석할 수 있음을 알 수 있었다.

가솔린엔진용 E-EGR 밸브 특성에 관한 연구 (A Study on the Characteristics of the Electronic EGR Valve for Gasoline Engine)

  • 박철웅;김창기
    • 한국자동차공학회논문집
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    • 제16권1호
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    • pp.127-133
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    • 2008
  • Since the 1960's, exhaust gas recirculation(EGR) has been used effectively in spark ignition(SI) engines to control the exhaust emissions of the oxides of nitrogen(NOx). The most important requirements for the application of EGR systems to conventional SI engines are controllable flow rate and good dynamic response. In order to evaluate the characteristics of the electronic EGR valve, a test bench which is consisted of blower, heater, air flow meter and driving unit for electronic EGR valve was set up to simulate engine operating conditions. During the tests, the valve actuation parameters were controlled and the valve lifts and flow rates were measured to infer the characteristics of EGR valve. The results confirmed the capabilities of mathematical analysis and it seems that the correction for the valve lift and potentiometer output is necessary to achieve precise control of EGR rates.

적층 벤더형 압전식 공압밸브의 내구 특성 (Endurance of Pneumatic Valve with a Multi-bender PZT Actuator)

  • 윤소남;박인섭
    • 동력기계공학회지
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    • 제18권2호
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    • pp.31-36
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    • 2014
  • In this paper, pneumatic valve which consists of valve body, valve controller, nozzle and a multi-bender PZT actuator was suggested and fabricated. The fabricated pneumatic valve was experimented for performance evaluation. From the experimental results, we know that the flow rate of the suggested valve is 23 lpm at the pressure difference of 1bar and the maximum flow rate is 30 lpm at the pressure difference of 4 bar. The flow rates after endurance test of 9.8 million were 22.57 lpm and 28.62 lpm at the pressure difference of 1bar and 4bar, respectably. Finally, it was verified that the B10 life of the suggested pneumatic valve is over 50 million.

압전식 비례제어밸브 (Proportional Flow Control Valve with PZT Actuator)

  • 윤소남;김찬용;함영복;윤석진;이경우
    • 한국세라믹학회지
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    • 제42권11호
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    • pp.758-762
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    • 2005
  • Gas valve for domestic use is used for flow control of LPG (Liquefied Petroleum Gas) or LNG (Liquefied Natural Gas) of which pressure is about $200\;mmH_{2}O(\fallingdotseq0.0196\;[bar])$. Currently, two kinds of valves such as rotary type and button type are widely used in many applications. But, these valves have some problems that they are not controllable and reliable. Piezo actuation combined with modem microelectronics provides a reliable, quiet, low energy, infinitely adjustable gas valve. In this paper, gas valve using piezo actuator which are bimorph and a circle type was studied. Also, Prototype for gas valve was manufactured and characteristics of the prototype gas valve were analyzed.

Development of the Pneumatic Servo Valve

  • Kim, Dong-Soo;Choi, Byung-Oh;Kim, Kwang-Young;Lee, Won-Hee
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2003년도 ICCAS
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    • pp.1146-1151
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    • 2003
  • Pneumatic servo valve is an electro-mechanical device which change electric signals to a proper pneumatic signals, that is, flowrate and pressure. In this study, a pneumatic servo valve was designed and each simulation was conducted on any variation in the flowrate depending upon the magnetic force of the linear force motor and the displacement of the spool. And permanent magnet was used as a material for the plunger of the servo valve. Thereby, a low electrical power consumption type coil was desinged. And a modeling for the coil design was conducted by using the magnetic circuit. also, the feasibility of the modeling was verified by using a commercial magnetic field analysis program. The designed and fabrication of the spool and sleeve, position sensor, servo controller and the dynamic characteristic verified by the experiment.

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