• Title/Summary/Keyword: Hydraulic Attenuator

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Hydraulic Pulsation and Noise Reduction using the Helmholtz Attenuator (헬름홀츠 감쇠기를 응용한 유압시스템의 유압맥동 및 소음 최소화 연구)

  • 김동현;이대옥;최근국
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.04a
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    • pp.614-619
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    • 1997
  • The hydraulic pressure pulsation has on the effected on the acoustic nosie and control performance of the hydraulic-servo system. The Helmholtz attenuator introduction on the hydraulic line is an efficient device to reduce the hydraulic pulsation. The salient feature of causing hydraulic pulsation and the frequency characteristics of Helmholtz attenuator are studied. The hydraulic filter design parameters such as the locating position, connecting orifice area and accumulator volume are mathematically analyzed. The instrumental works are carried out with the remarkable reduction of the hydraulic pressure pulsation magnitude and the acoustic noise level.

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An Investigation into the State-Space Model for a Hydraulic Attenuator (유압 감쇄기의 상태공간 모델에 대한 연구)

  • Lee, Jae-Cheon
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.5
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    • pp.168-175
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    • 2002
  • The hydraulic acoustic attenuator fur an automotive active suspension system is so highly nonlinear and of high order that the analysis in time-domain has been performed quite little. In this paper, a state-space representation of the dynamics for a hydraulic attenuator was presented utilizing the electrical analogy. And the results of experiment were compared with those of simulation to validate the state-space model proposed. The comparison revealed that the state-space model proposed is practically applicable to estimate the dynamic responses of the hydraulic attenuator in time-domain.

Impedance Characteristics of an Expansion-Resonator Type Pulsation Attenuator(Attenuation on Flow and Pressure Ripple form a Hydraulic Piston Pump) (팽창 공명기형 맥동 감쇠기의 임피던스 특성(유압용 피스톤 펌프의 유량.압력맥동 감쇠))

  • 이상기
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.9 no.1
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    • pp.88-95
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    • 2000
  • In this paper, an expansion-resonator type pulsation attenuator is proposed to absorb and attenuate flow an pressure ripple with high frequencies generated from hydraulic control systems. The basic principle of a pulsation attenuator proposed here is applied to propagation, reflection, absorption of pressure waves at the cross section of discontinuity and resonance in the pipeline. It has advantage of the compact size and high degree fo freedom for installation in hydraulic systems. The design scheme based on distributed parameter pipeline system with dissipative viscous compressible model is developed. To investigate the reduction of flow and pressure ripple with high frequencies produced by swash plate type axial piston pump, two kinds of attenuators are manufactured. It is experimently confirmed that the spectral intensity of flow and pressure ripple with high frequencies from the pump are reduced up to about 20$^{\circ}$~30dB by using attenuators proposed here. The calculated results were in good agreement with the measured values. From there sults of this study, it is shown that an expansion-resonator type pulsation attenuator is effective in a wide frequency ranges to attenuate the flow and pressure ripple from hydraulic components.

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REDUCTION OF PRESSURE RIPPLES USING A PARALLEL LINE IN HYDRAULIC PIPELINE

  • KIM K. H.;JANG J. S.;JUNG D. S.;KIM H. E.
    • International Journal of Automotive Technology
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    • v.6 no.1
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    • pp.65-70
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    • 2005
  • Pressure ripples, which are inevitably generated by a fluctuation of flow rate caused by a pump mechanism, include noises and vibrations in hydraulic pipeline. These noises and vibration deteriorate the stability and accuracy of hydraulic systems. The accumulator and hydraulic attenuator are normally used to reduce the pressure ripples. In this study, a parallel line is introduced to the hydraulic pipeline for the hydraulic system with a bent-axis piston pump as a method to reduce the pressure ripples. The dynamic characteristics of the hydraulic pipeline with a parallel line are analyzed by a transfer matrix in the frequency domain. The usefulness of the hydraulic pipeline with a parallel line was ascertained by experiment and simulation. The results from the experiment and simulation show that the hydraulic pipeline with a parallel line were effective in reducing the pressure ripples.

A Study on the Reduction in Pressure Ripples for a Bent-Axis Piston Pump by a Phase Interference (위상간섭을 이용한 사축식 액셜 피스톤 펌프의 압력맥동 감소에 대한 연구)

  • 김경훈;최명진;이규원;장주섭
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.9
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    • pp.103-110
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    • 2004
  • Pressure ripples yield noise and vibration in hydraulic pipelines, which are inevitably generated by a fluctuation of flow rate in the pump mechanism, and such noise and vibration deteriorate the stability and accuracy of hydraulic systems. To reduce the pressure ripples, accumulator and hydraulic attenuator are normally used. In this study, parallel pipeline with a bent-axis piston pump is introduced to a hydraulic pipe system as a method for reducing the pressure ripples and using the transfer matrix method, the dynamic characteristics of the pipe system are analysed and compared with experimental results. The results show that the phase interference using parallel pipeline with a bent-axis piston pump is effective to reduce the pressure ripples in the hydraulic pipelines.

Construction of a Pilot Headbox System and Pressure Monitoring Apparatus for the Development of High Speed Hydraulic Headboxes

  • Youn, Hye-Jung;Lee, Hak-Lae
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.35 no.5
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    • pp.37-45
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    • 2003
  • To investigate the influence of the design and operating parameters of the headbox on hydrodynamics, a pilot headbox system and pressure monitoring apparatus were constructed. The pilot headbox system consisted of a circulating water reservoir, centrifugal pump, distributor, turbulence generator and slice. The distributor was designed to function as a pressure attenuator. Flow rate to the headbox and MD and CD velocity profiles in the slice zone were monitored using an ultrasonic flowmeter and Pitot tubes, respectively. As the distance from the step diffusor increased, evener CD velocity profile was observed. Wall effect increased with the increase of the velocity. Flow stability in the headbox was evaluated by injecting a dye at the outlet of the distributor. Application of theoretical analysis based on CFD in designing headboxes is briefly discussed.