• Title/Summary/Keyword: MR 밸브

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A Numerical Study of New Vehicle Hydraulic Lift Activation by a Magneto-rheological Valve System for Precise Position Control (정밀 위치 제어를 위해 MR 밸브 시스템을 활용한 차량 유압 리프트에 대한 수치해석적 고찰)

  • Lee, TaeHoon;Park, Jhin-Ha;Choi, Seung-Bok;Shin, Cheol-Soo;Choi, Ji-Young
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.27 no.1
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    • pp.28-35
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    • 2017
  • Recently, conventional hydraulic car lift systems face the technological limitations due to a lack of height control. The demand for height controllability is required in many tasks such as wheel alignment, and requires compensation for the structural deformation of the lift caused by irregular load distribution. In order to resolve this limitation of the conventional car lift, in this work, a new type of a hydraulic vehicle lift using a magneto-rheological (MR) valve system is proposed and analyzed. Firstly, the dynamic model of vehicle lift is formulated to evaluate control performance; subsequently, an MR valve is designed to obtain the desired pressure drop required in the car lift. Next, a proportional-integral-derivative (PID) controller is formulated to achieve accurate control of the lifting height and then computer simulations are undertaken to show accurate height control performances of the proposed new car lift system.

Electromagnetic Design and Performance Evaluation of an MR valve (MR 밸브의 전자기적 설계와 성능 평가)

  • Kim, Ki-Han;Nam, Yun-Joo;Park, Myeong-Kwan
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.968-973
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    • 2007
  • This paper presents an electromagnetic design for the magneto-rheological fluid valve. The MR valve can control high-level fluid power without moving parts, due to the apparent viscosity controllability of the MR fluid in magnetic fields. In order to improve the static characteristic of the MR valve, the length of the flux path is decreased by removing the unnecessary bulk of the yoke. Then, in order to improve the dynamic and hysteretic characteristics, the magnetic reluctance of the ferromagnetic material is increased by minimizing the cross sectional area through which the flux passes. Two MR valves, one is a conventional type valve and the other is the proposed one, were fabricated and performance evaluation is experimentally achieved through the comparison study using by-pass damper system.

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Electromagnetic Design and Performance Evaluation of an MR Valve (MR 밸브의 전자기적 설계와 성능평가)

  • Kim, Ki-Han;Nam, Yun-Joo;Park, Myeong-Kwan
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.32 no.3
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    • pp.240-249
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    • 2008
  • This paper presents an electromagnetic design method for magneto-rheological (MR) valves. Since the apparent viscosity of MR fluids is adjusted by applying magnetic fields, the MR valves can control high-level fluid power without any mechanical moving parts. In order to improve the performances of the MR valve, it is important that the magnetic field is effectively supplied to the MR fluid. For the purpose, the magnetic circuit composed with the yoke for forming magnetic flux path, the electromagnetic coil and the MR fluid should be well designed. In order to improve the static characteristic of the MR valve, the length of the magnetic flux path is decreased by removing the unnecessary bulk of the yoke. Also, in order to improve its dynamic and hysteretic characteristics, the magnetic reluctance of the magnetic circuit should be increased by minimizing the cross-sectional area of the yoke through which the magnetic flux passes. After two MR valves, one is a conventional type valve and the other is the proposed one, are designed and fabricated, their performances are evaluated experimentally.

A Study on the Analysis of Magnetoresistive Behavior in Giant Magnetoresistive Spin Valve Trilayer Films (거대자기저항 스핀밸브 삼층박막의 자기저항 거동 해석에 관한 연구)

  • 김형준;이병일;주승기
    • Journal of the Korean Magnetics Society
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    • v.8 no.4
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    • pp.224-230
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    • 1998
  • The relationships between R-H curves of gaint magnetoresistance (GMR) spin valve trilayer films and M-H curves of each magnetic layer consisting of the trilayer films were analyzed and simple formula representing the relations between the curves were suggested for theoretical analysis and study of magnetoresistance (MR) in those films, especially where the MR is from the difference of coercivity. Using two kinds of NiFe/Cu/Co films, which had been deposited on Cu(50 $\AA$)/Si(111, 4$^{\circ}$ tilt-cut) and Cu(50 $\AA$)/glass, R-H and M-H curves were measured and compared with the calculated ones, which were obtained by appying the M-H curves of single NiFe and Co films, deposited on the same substrates, to the previously reported single-domain and multi-domain models. The calcuated ones were well consistent with the measured ones and the suggested simple relationships between R-H and M-H curves are thought to be very useful for the deep understanding of MR behavior and the reasonable approach to improve MR properties in GMR spin valve trilayer films.

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Magnetoresistance Effect of Ta/NiFe/Cu/Co Pseudo Spin Valve Structure (Ta/NiFe/Cu/Co Pseudo 스핀밸브 구조의 자기저항 효과)

  • Joo, Ho-Wan;Choi, Jin-Hyup;Choi, Sang-Dae;Lee, Ky-Am
    • Journal of the Korean Magnetics Society
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    • v.14 no.1
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    • pp.25-28
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    • 2004
  • The dependence of sensitivity, MR ratio, coercivity (Hc) and switching fields as a function of thickness of each magnetic layers(Co, NiFe and Cu) were investigated in pseudo spin valves with a structure of Ta/NiFe/Cu/Co. As measured results dependence of the thickness of each magnetic layer, we obtained MR ratio of 7.26% for Ta(4 nm)/NiFe(7.5 nm)/Cu(3 nm)/Co(5 nm) pseudo spin valves. Also, we could control properties of magnetoresistance for independent magnetization courses of each magnetic layer. Especially, we found that we could control coercivity as constant MR ratio dependence of Co thickness.

A Study on the Design of Valve Mode MR Damper using Permanent Magnet (영구자석을 이용한 밸브모드 MR 감쇠기 설계에 관한 연구)

  • Kim, Jung-Hoon;Oh, Jun-Ho
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.10
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    • pp.69-76
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    • 2000
  • Lots of semi-active control devices have been developed in recent years because they have the best features of passive and active system. Especially, controllable magneto-rheological(MR) fluid devices have received significant attention in these area of research. The MR fluid is the material that reversibly changes from a free-flowing, linear viscous fluid to a semisolid with a controllable yield strength in milliseconds when exposed to a magnetic field. If the magnetic field is induced by moving a permanent magnet instead of applying current to a solenoid, it is possible to design a MR damper consuming low power because the power consumption is reduced at steady state. This paper proposes valve mode MR damper using permanent magnetic circuit that has wide range of operation with low power consumption, a design parameter is adopted. The magnetic circuit, material of choke and choke type are selected experimentally with the design parameter. The behaviors of the damper are examined and torque tracking control using PID feedback controller is performed for step, ramp and sinusoidal trajectiories.

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PWM Control of On-Off Valves using MR Fluid Spool (MR유체 스풀을 이용한 온-오프 밸브의 PWM제어)

  • 양택주;배형섭;박명관
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.1709-1712
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    • 2003
  • Almost the on-off type solenoid valve is used to hydraulic system. It has a strong point that concerned about rapid response, electric and hydraulic characteristic at the same time. In this paper we produced the new type spool using the MR fluid different from the others. Also we controlled a cylinder position through PWM method. And using the AMESim software, We compared our new type spool valve with existed one from data of simulation and experiment.

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Magnetoresistance of IrMn-Based Spin Filter Specular Spin Valves (IrMn 스핀필터 스페큘라 스핀밸브의 자기저항 특성)

  • Hwang, J.Y.;Rhee, J.R.
    • Journal of the Korean Magnetics Society
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    • v.14 no.6
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    • pp.236-239
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    • 2004
  • We studied the specular spin valve (SSV) having the spin filter layer (SFL) in contact with the ultrathin free layer composed of Ta3/NiFe2/IrMn7/CoFel/(NOLl)/CoFe2/Cu1.8/CoFe( $t_{F}$)/Cu( $t_{SF}$ )/(NOL2)/Ta3.5 (in nm) by the magnetron sputtering system. For this antiferromagnetic I $r_{22}$M $n_{78}$-pinned spin filter specular spin valve (SFSSV) films, an optimal magnetoresistance (MR) ratio of 11.9% was obtained when both the free layer thickness ( $t_{F}$) and the SFL thickness ( $t_{SF}$ ) were 1.5 nm, and the MR ratio higher than 11% was maintained even when the $t_{F}$ was reduced to 1.0 nm. It was due to increase of specular electron by the nano-oxide layer (NOL) and of current shunting through the SFL. Moreover, the interlayer coupling field ( $H_{int}$) between free layer and pinned layer could be explained by considering the RKKY and magnetostatic coupling. The coercivity of the free layer ( $H_{cf}$ ) was significantly reduced as compared to the traditional spin valve (TSV), and was remained as low as 4 Oe when the $t_{F}$ varied from 1 nm to 4 urn. It was found that the SFL made it possible to reduce the free layer thickness and enhance the MR ratio without degrading the soft magnetic property of the free layer.

The Dependences of Magnetoresistance and Exchange Biasing on Annealing temperature in Top and Bottom Type Specular Spin Valves with Nano-oxide Layers (나노 옥사이드 층을 가진 스펙큘라 스핀밸브의 자기저항 특성 및 교환바이어스의 열처리 온도 의존성)

  • Jang, S.H.;Kang, T.;Kim, H.J.;Kim, K.Y.
    • Journal of the Korean Magnetics Society
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    • v.12 no.3
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    • pp.103-108
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    • 2002
  • We investigated magnetoresistance(MR) and exchange bias properties by annealing in top and bosom type spin valves (SV) with nano-oxide layers (NOL). In top SVs with NOL, MR ratio of 9.2% is obtained after postdeposition annealing at 250$\^{C}$. In bottom SVs with NOL, MR ratio of 10.1 % is obtained after postdeposition annealing at 250$\^{C}$. Therefore, specular reflection of the NOL in bottom SVs is higher than that of the NOL in top SVs. Exchange biasing of bottom SVs with NOL is 28% higher than that of bottom SVs without NOL after annealing. This enhancement of exchange biasing is thought to be due to the reduced magnetic moment of the pinned layer with NOL and enhanced (111) FeMn texture.

A study on the force control of a servo actuator with built-in MR Valve (MR 밸브 내장형 서보 액추에이터의 힘 제어에 관한 연구)

  • Ahn K.K.;Song J.Y.;Kim J.S.;Ahn Y.K.;Park J.H.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.3 no.1
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    • pp.1-6
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    • 2006
  • A servo actuator with a valve using MR (Magneto-Rheological) fluid is proposed for fluid control systems. The MR fluid is well known as a functional fluid whose apparent viscosity is controlled by the applied magnetic field strength. The pressure in the MR cylinder can be controlled by the applied magnetic field strength. Good points of the MR cylinder are more simple, compact and reliable structure than a conventional oil hydraulic cylinder. The experimental results show that the MR cylinder could be used as a servo actuator.

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