• Title/Summary/Keyword: Hydraulic Analysis

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A Study on the Dynamic Characteristics of ABS Hydraulic Control Valve (ABS 유압 제어 밸브의 동 특성 해석에 관한 연구)

  • 김병우;송창섭
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.4
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    • pp.121-130
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    • 2001
  • For the purpose of optimal control of anti-lock brake systems, precise dynamic characteristics analysis of hydraulic modulator, especially solenoid valve is necessary. However, most of researches so far have dealt with dynamic characteristic analysis of valve itself, and the results have been restrictively applied to the actual ABS modulator, where hydraulic pressure is acting. In this study, mathmatical modeling and experimental analysis were peformed in order to evaluate the valve dynamic characteristics when the hydraulic pressure is applied. High pressure on the master cylinder that affects on the valve dynamic characteristics have been analyzed quantitatively, and performance improvement methods have been suggested through parameter study. Consequently, results of solenoid valve dynamic characteristics analysis derived in the study can be utilized as criteria for the optimal control of anti-lock brake systems.

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Friction Characteristics of an Hydraulic Cylinder for an Automotive Manual Clutch (자동차 수동 클러치 유압 실린더의 마찰 특성)

  • Lee, Byoung-Soo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.14 no.4
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    • pp.32-38
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    • 2006
  • A clutch hydraulic system for automotive manual transmissions transfers hydraulic pressure generated by driver's pedal manipulation to the clutch mechanism. The foot effort when the clutch pedal is pushed is different than that when the clutch is returned. The effort or load difference, called hysteresis, is caused by the friction produced between rubber seal and inner wall inside the hydraulic cylinder. This clutch pedal travel foot effort hysteresis is essential for a clutch hydraulic system design and analysis. The dynamic model for a clutch hydraulic system is developed and a simulation analysis is performed to estimate the fiction coefficient as a function of the cylinder pressure. The simulation result is then compared to the measurements obtained from a clutch hydraulic system tester to ensure the reliability of the dynamic model and the coefficients estimated. Also the estimated friction coefficients at various pressure values are compared to those reported by an independent study.

Life Analysis of High Pressure Hydraulic Hose Assemblies by Impulse Test (충격압력을 이용한 고압용 유압호스 조립체의 수명분석)

  • Lee Y.B.;Kim H.E.;Yoo Y.C.;Park J.H.;Ko J.M.;Kwak D.H.;Lee J.K.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.1 no.1
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    • pp.10-16
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    • 2004
  • The failures such as leakage and burst stemmed from the repetitive motions of bending and stretching of the assembly of hydraulic hose in construction machines, agriculture machines, vehicles, and industrial heavy machines can induce big troubles. Therefore, the hydraulic hose itself eventually requires an estimation of life to operate the hydraulic system safely. In this research, we have qualitatively selected the efficient test items by the analysis of the life and potential failures of hydraulic hose. We have used more than seven of hydraulic hoses simultaneously for the research. We have applied impulse pressure and half omega flexing motions to the accelerated life testing Test results have been expressed by employing weibull plot.

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Characteristic Analysis of the Damper Cylinder for the Automotive Hydraulic Clutch System (차량용 유압 클러치시스템의 댐퍼실린더 특성해석)

  • Lee, Choon-Tae
    • Transactions of the Korean Society of Automotive Engineers
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    • v.16 no.3
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    • pp.151-158
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    • 2008
  • The clutch system is a subcomponent of the transmission that is designed to engage and disengage power flow between the engine and the transmission. Recently, the engine power of automobile has been continuously increased because of customer's demand for the bigger one. As the engine power is increased, the vibration transmitted to the hydraulic clutch operating system has been increased. Therefore the demand for the reduction of clutch pedal vibration during the operation has been increased. This paper describes the pressure pulsation reduction characteristics of the damper cylinder which is applied to the hydraulic clutch operating system. And the purpose of this study is to propose an analysis model and investigate the effect of the design variable variations for the hydraulic clutch system. Especially, we studied the effect of damper cylinder parameter variations on the hydraulic clutch system performance.

Hydraulic System Simulation and Vehicle Dynamic Modeling for the Analysis and Development of Tire Roller Prototype (유압 구동식 타이어 로울러 Prototype의 유압 시스템 설계 및 차량 동역학적 모델링)

  • 박춘식;김준호;김상겸;김정하
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.137-137
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    • 2000
  • In this research. we developed Tire Roller Prototype which is operated hydraulic transmission system. For develop the theoretically computer aided system, we practiced the simulation of hydraulic system and dynamic modeling and will compare with the experiment results of Tire Roller Prototype. We conceptualize the new hydraulic system and derive the equations of motion for dynamic analysis. Finally, we will design the controller, which can manage the hydraulic circuit of servo mechanism system. We define new hydraulic system and integrate modeling of Tire Roller through simulation of h\ulcornerdraulic system and design of controller. From above procedure. Hydraulic transmission system characteristics and target performance can be investigated. To follow the required performance, we select the parts of Tire Roller. We manufactured the prototype of Tire Roller, and will install the equipment for experiment.

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입도분석과 현장수리시험에 의한 수리전도도의 특성 비교

  • Ham Se-Yeong;Jeong Jae-Yeol;Lee Jeong-Hwan;Kim Hyeong-Su;Han Jeong-Sang
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2005.04a
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    • pp.446-450
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    • 2005
  • Hydraulic conductivity of unconsolidated media can be determined by aquifer tests, laboratory tests and empirical equations based on grain size analysis. Commonly, the different methods give different hydraulic conductivities. Grain size measurements were done to determine hydraulic conductivity, using 184 soil samples collected from eight boreholes in a riverbank filtration area, Daesan-Myeon, Changwon City, Korea, Pumping tests were conducted at the riverbank filtration area. The average hydraulic conductivity by the empirical relations from grain size measurements comes out around $10^{-2}m/s$, 22 to 55 times higher than by the pumping test analyses. The hydraulic conductivity obtained from the empirical equations is interpreted to have a relationship with steady-state condition while that obtained from the pumping tests is interpreted to have a relationship with unsteady-state condition. Thus, hydraulic conductivity obtained from various methods should be critically analyzed for reasonable management of groundwater development.

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Design of a Hydraulic System for a Power Split type CVT (동력분기식 무단변속기의 유압구동부 설계)

  • 김정윤
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.1
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    • pp.168-173
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    • 2004
  • This article describes the design of a hydraulic system for a power split type continuously variable transmission (CVT). The CVT considered here, is composed of planetary gears, clutches, and a torque converter which is mainly used for the realization of CVT function. Similar to automatic transmissions, the hydraulic system of CVT is designed for supplying hydraulic flows and pressures to each component of CVT, in order to activate the clutch engagements and torque converter operation, and to cool the drivetrain. By using the mathematical models of drivetrain, a simulation program was developed to investigate the power performance of CVT equipped vehicle and the operating conditions of each component of CVT. And the design parameters of the hydraulic system and clutches were calculated using the operating conditions and power requirements which obtained from the simulation results. Finally the hydraulic circuit design of prototyped valve body is presented based on the numerical results of this analysis.

Experimental Thermal Analysis of Hydraulic System in a Special Vehicle (특장차량 유압시스템 내 열적 특성 분석)

  • Choi, Yu Hyun;Lee, Sang Ho
    • Journal of the Korean Society of Mechanical Technology
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    • v.13 no.4
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    • pp.85-91
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    • 2011
  • Experimental analysis has been carried out to investigate thermal characteristics of hydraulic system in special vehicles. Hydraulic system performance is largely influenced by oil temperature, and there are considerable performance decline and malfunctions in the system for high temperature conditions caused by heavy load and continuous operation. Transient oil temperature and pressure variation are analyzed and heat generation rates in the several main system parts are compared for various flow rates. With the start of system operation oil temperature gradually increases, and viscosity deceases by about 70% as temperature increases from $20^{\circ}C$ to $80^{\circ}C$. Operation pressure in the hydraulic system decreases with oil temperature, and its variation rate becomes less steep as oil temperature increases. Heat generation rate in hydraulic pump also depends on the oil temperature, and it reaches maximum near $50^{\circ}C$. These results in this study can be applied to optimal design of efficient hydraulic system in special vehicles.

Development of Hydraulic Device Performance Test Equipment Automation Process (유압 디바이스 성능 검사 장비 자동화 공정 개발)

  • Kim, Hong-Rok;Chung, Won-Jee;Seol, Sang-Seok;Park, Sang-Hyeok;Lee, Kyeong-Tae
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.19 no.10
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    • pp.74-80
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    • 2020
  • Crawler-type hydraulic devices facilitate forward and backward driving of construction equipment by converting power into mechanical energy. The existing hydraulic device performance test process is time- and labor-intensive. This study aims to improve efficiency and productivity by automating the hydraulic device production performance test processes, which have been separately conducted so far. We also used SolidWorksⓇ, a 3D modeling program, and ANSYSⓇ, a structural analysis tool, for structural analysis and to verify the suitability of fixing pins required for connecting a hydraulic device to performance test equipment. Our results that employing an automated hydraulic device performance test process improves efficiency.

Case of Improving Design by Using Analysis Model of Hydraulic System for Dental Chair (치과용 유니트체어 유압구동 시스템 해석모델을 활용한 개선설계 사례)

  • Dae Kyung Noh;Dong Won Lee;Taek June Kim;Joo Sup Jang
    • Journal of Drive and Control
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    • v.20 no.2
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    • pp.1-6
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    • 2023
  • This study aims to develop a Korean dental chair hydraulic circuit by improving the existing equipment in order to localize foreign leading companies' products. The suggested Hydraulic circuit can be applicable to varied sectors where height and backrest angle control of chair-type equipment are required. The study followed the steps below. First, three kinds of foreign hydraulic circuits were analyzed and three kinds of Korean dental chair hydraulic circuits were suggested. Second, it was determined whether the three kinds of Korean hydraulic circuits operate normally through SimulationX, a software specialized in multi domain analysis, and the effectiveness of each circuit was examined.