• 한국자동차공학회논문집
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• 제8권6호
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• pp.70-78
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• 2000

A balanced vane pump for the use of automotive power steering systems generates a flow ripple which is imposed upon the mean flow rate. The flow ripple interacts with the characteristics of the connected pipes, valves and steering gear in a complex manner to produce a pressure ripple, also known as fluid-borne noise. In order to reduce vibration level and produce quieter and more reliable power steering systems, it is important to measure the flow ripple produced by a pump with high accuracy and fast response. In this paper, the flow ripple generated by a vane pump in automotive power steering systems is measured by the remote instantaneous flow rate measurement method (RIFM) using hydraulic pipeline dynamics. In experiment, flow and pressure ripple wave forms are measured under various operating conditions. Also, the parameters affected upon the flow and pressure ripple are investigated by the frequency analysis.

• 한국생산제조학회지
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• 제7권3호
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• pp.22-28
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• 1998

This paper presents experimental investigations on the attenuation characteristics of pressure ripple in automotive power steering hydraulic hoses. Also, a mathematical model of hydraulic hoses is proposed to support design of the power steering hydraulic circuit and analyze the attenuation characteristics of pressure ripples. The experimental results show that the pulsation attenuation characteristics of hydraulic hoses is remarkably affected by the flexible metal tube inserted coaxially inside a hydraulic hose with a finite length as well as viscoelastic properties of hose wall. It is also shown that the predicted results by the model proposed here agree well with the measured results over a wied range of frequency.

• 한국자동차공학회논문집
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• 제7권9호
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• pp.105-111
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• 1999

The paper presents development of a Hardware-In-the-Loop simulation (HILS) system for the purpose of testing performance, stability, and reliability of an electronic power steering system(EPS). In order to realistically test an EPS by the proposed HILS apparatus, a simulated uniaxial dynamic rack force is applied physically to the EPS hardware by a pnumatic actuator. An EPS hardware is composed of steering wheel &column, a rack & pinion mechanism, andas motor-driven power steering system. A command signal for a pneumatic rack-force actuator is generated from the vehicle handling lumped parameter dynamic model 9software) that is simulated in real time by using a very fast digital signal processor. The inputs to the real-time vehicle dynamic simulation model are a constant vehicle forward speed and from wheel steering angles driven through a steering system by a driver. The output from a real-time simulation model is an electric signal that is proportional to the uniaxial rack force. The vehicle handling lumped parameter dynamic model is validated by a fully nonlinear constrained multibody vehicle dynamic model. The HILS system simulation results sow that the proposed HILS system may be used to realistically test the performance stability , and reliability of an electronic power steering system is a repeated way.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2011년도 추계학술논문집 2부
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• pp.421-424
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• 2011

연비절감 및 조향감 향상을 위한 EHPS 시스템은 엔진 동력 기반의 HPS(Hydraulic Power Steering)시스템과는 달리 탈 엔진형 조향 기술로써 동력원인 BLDC 모터, 고압펌프 일체형 모듈, 상용 HPS 시스템의 기본 유압회로, 조향계 시스템 및 BLDC 모터를 제어하고 최적 조향력을 생성하기 위한 로직이 포함된 ECU로 구성되며. 주요구성 모듈은 펌프부, 모터부, 제어부로 분류된다. 본 논문에서는 펌프부의 외접형 Gear펌프의 시제품 제작하였고 구동토크 측정실험의 Data를 통해 기존 EHPS용 Gear펌프와 비교평가를 하였다.

• 한국자동차공학회논문집
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• 제16권4호
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• pp.135-142
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• 2008

Hydraulic power steering system has been adopted in seniority passenger and commercial vehicle system for an easy maneuverability and a smoother ride. In this study, hydraulic power steering system analysis model which includes hydraulics and mechanical sub-systems was developed using commercial software, AMESim in order to predict characteristics for various steering components. Each component which constructs system was modeled and verified by experimentally obtained characteristics curves of each components. The parameter sensitivity analysis such as valve opening area, torsional stiffness of torsion bar for system design are carried out by the analysis and experimental method. The predicted results by the development model were a good agreement with experimentally obtained results. The sensitivity investigation results rotary torque when changing an input shaft edge width, was most sensitive, to change in angle and slot width and supply flow of input shaft edge is not a lot sensitively.

• 동력기계공학회지
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• 제4권2호
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• pp.65-70
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• 2000

The shimmy phenomenon, or the radial vibration of steering wheel, happens frequently at a high speed, complicated with suspension system, steering system, vehicle body, engine, transmission and tire. In this study, the suspension system and steering system are modeled by the reference of vehicle body design coordinates(T.L.H), the coordinate system usually used by passenger car maker. In addition, the theoretical results from numerical method have been investigated and compared with the experimental ones by the correlating analysis between the tire and sub-system. The steering and suspension system modeled for the numerical analysis are both independent type. This study developed an analysis program which could forecast the shimmy level in advance by the variation of properties in each system and the change in design of new model.

• 한국정밀공학회지
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• 제16권12호
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• pp.214-221
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• 1999

In this research, a power-assisted steering system is modeled as a part of a full vehicle dynamic model. The dynamic model of the steering system incorporates hydraulic and dynamic relations between major parts of a steering system, such as steering column, control valve, rack and pinion gear. Through an experimental setup of the steering system, the steering system model is validated. The steering model is included in a full vehicle dynamic model of a car, where kinematic relations between steering and suspension system are defined, and various simulations are performed to evaluate the performance of steering system in conjunction with overall dynamic performance of the vehicle.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.51-56
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• 2002

High pressure hose having tuning cables, called 'Resonator hose' is frequently used to attenuate pressure ripple generated by the pump for reducing the vehicle interior noise. A number of studies have been conducted on the resonator hose and its analytical models. However, there are few studies which deal with the influence of resonator hose on vehicle interior noise because the most of studies focused on transmission loss of the resonator hose. This paper presents NVH test results of power steering system and frequency analysis results. In the frequency analysis, both the relations between vibration, pressure ripple and vehicle interior noise and also the design parameters of high pressure hose influencing on vehicle interior noise were discussed. The test was done for various high pressure hose specimens in full turn condition.

• 한국자동차공학회논문집
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• 제10권4호
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• pp.166-174
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• 2002

Power steering systems far automobile are becoming ever more popular because they reduce steering efforts of the drivers, especially during parking lot maneuver. In this paper, the controller of the motor driven hydraulic power steering(MDHPS) has been designed and developed. This system uses a power source of DC motor instead of engine power source for power steering drive oil pump. The developed MDHPS system is accomplished a highly sensitive power steering resulted from electronic control under variable driving condition. Furthermore, this system is more improvement than type of engine driving far fuel economy.

• 한국공작기계학회논문집
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• 제14권1호
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• pp.66-72
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• 2005

The working tactor of this study, an agriculture machine, is consisted of 4 wheel driving system with gear trains and 4-type wheel steering system. Since technological regions for 4 wheel driving system and 4-type wheel steering system are some large, we divide on two studies on 4 wheel driving system and 4-type wheel steering system This study develops transmission and axle that are very important units for strong working operation because the power of tractor is largely affected by transmission and axle. Even if the development of the power train is some common technology, it is very complicated work and needs many experience know-hows. So, for new given specifications fitted to the working tractor, a kind of new agriculture machine, this study haws out processes that are development of assembly drawing and strength analysis through classical method and CAE software for all internal parts and housing cases.