• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.3
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• pp.33-38
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• 2002

This paper deals with pressure ripple attenuation far separated-type Hydrostatic Transmission (HST) consisting ova variable axial piston pump connected in an open loop to a fried displacement axial piston motor. Pressure ripples in HST is major source of vibration which can lead to fatigue failure of components and cause noise. In order to reduce the pressure ripple, an annular tube tripe hydraulic filter is proposed to attenuate pressure ripples with the high frequencies components to achieve better noise reduction in HST. The basic principle of a hydraulic filter is allied to propagation of pressure wave, reflection, absorption in cross section of discontinuity and resonance in the hydraulic pipeline. It is experimentally shown that the hydraulic filter attenuates about 30∼40dB of pressure ripple with high frequencies. These results will assist in modeling and design of noise reduction in hydraulic control systems, and provide a means of designing a quieter HST.

• Journal of Drive and Control
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• v.7 no.3
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• pp.20-28
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• 2010

• Journal of the KSME
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• v.20 no.2
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• pp.141-144
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• 1980

유압장치를 사용함에 따라 발생하는 오염물의 순서에 따라 그에 대한 대책을 다음 (표 1)에 표 시한다. 열화, 오염 요인의 점검 항목으로서는 (1) 발생녹 (2) 수분함유량 (3) 스러지량 (4) 외부 로의 혼입 오염물 (5) 열의 발생 복사열 (6) 도료 (7) 필터 (8) 유압작 등유가 있다.

• 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.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.117-123
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• 2003

This paper deals with pressure ripple and noise reduction characteristics for a hydrostatic transmission(HST) consisting of a variable axial piston pump connected in an open loop to a fixed displacement axial piston motor. Pressure ripples in HST is major source of vibration, which can lead to fatigue failure of components and cause noise. In order to reduce the pressure ripple, an annular tube type hydraulic filter proposes to absorb pressure ripples with the high frequencies components to achieve better noise attenuation in HST. The basic principle tube is applied to propagation of pressure wave, reflection, absorption in cross section of discontinuity and resonance in the hydraulic pipeline. It is experimently confirmed that a hydraulic filter is absorbed to be about 30∼40dB of pressure ripple with high frequencies. These results will assist in modeling and design of noise reduction in hydraulic control systems, and here, should provide a means of designing a quieter HST.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.281-286
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• 1998

In this paper, a Helmholtz resonator type hydraulic filter is proposed to absorb flow and pressure ripple produced from a axial piston pump. The basic principle of hydraulic filter is applied to propagation of preossure waves, reflection, absorption in cross section of discontinuity and resonance in the pipeline. This filter has advantage of the compact size and high degree of freedom of installation. The design scheme of hydraulic filter based on viscous wave theory are developed and manufactured two kinds of filter to investigate damping capability. It is experimently confirmed that these filter is absorbed to be about 20dB of flow and pressure ripple with high frequencies.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.1
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• pp.15-24
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• 1986

Pressure trasients must deal with safety problem of system. For identification of physical situation that can and method of limiting surges are essential consideration in sucessful design. The finite difference equation by method of characteristics are derived from the governing equation of unsteady flow in a pipe, and solved by using boundary condition derived. A computer program which can simulate general hydraulic system is developed by using finite difference equations and boundary conditions derived. The sumulated resulted by developed computer program are in fair agreement with experiment result.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.10
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• pp.83-92
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• 2004

This paper concerns servo filter design for KSR-III gimbal engine actuation system. When the actuator system is attached to engine mount frame, unexpected resonant modes in low frequency can occur and make the control system unstable. In order to prevent the resonance in the actuation system, a proper lowpass servo filter is designed. Based on the dynamic test data including the resonant effect, the shape of the servo filter is determined, and then the corresponding parameters are optimally designed. The best solution is finally selected via dynamic tests including the servo filter.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.1
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• pp.69-78
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• 1999

In this study a new pattern of pressure control of hydraulic cylinder using high speed On-Off solenoid valve in the electro-hydraulic system has been suggested. The control valve is 3-way high speed On-Off solenoid valve which is operated by PWM(Pulse Width Modulation)control signal. The high speed On-Off solenoid valve has a tendency to induce severe pressure fluctuation in the hydraulic actuator so it has not been used for the purpose of closed loop control with direct pres-sure feedback. In this study closed loop control with direct pressure feedback is enabled by using a digital filter which has linear minimum mean square filter algorithm. Through some experiments it is confirmed that stable pressure control can be realized by the proposed control technique.

• Journal of IKEEE
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• v.18 no.3
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• pp.420-426
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• 2014

In this paper, we have implemented the low temperature fluidity test system with the composited fuel filter and heater, which has tested the low temperature fluidity of gasoline, an engine start time, the consumption of electricity and power to evaluate the system performance. The test condition have used the diesel fuel, the normal temperature, the diesel fuel supply pressure $3.4kgf/cm^2$ at $-20{\sim}-30^{\circ}C$, the fuel supply quantization 60 l/H, the setting current 30 A and the voltage $13V_{dc}$. In order to simulate the operation of diesel fuel filter, we will establish the composited fuel filter into test jig, and be filled with chamber tank and filter by a constant flow quantization and pressure. After these, it shall be cold for setting time. And then we have measured the consumption current and power of heater, an operating time and pressure of filter.