This paper deals with a center-closed rotary servo valve in a hydraulic power steering (PS) system having an improved straight line stability during driving.Conventional rotary servo valves are of a center-open type and are poor in straight line stability because the assist pressure to steer occurs with even slight steering inputs.In the vicinity of neutral position the center-closed rotary servo valve does not produce assist pressure and leaves room for manual steering effort. The center-closed rotary servo valve is composed of a center-closed circuit and a center-open circuit in parallel. The center-closed circuit precisely controls the direction of oil flow to the cylinder chamber A or B in the vicinity of neutral position. The chamfers formed at center-closed metering edges control a lower level of assist pressure. Also the change of assist pressure from manual- to power-steering is smooth.So we have investigated characteristics of a steering gearbox with a center-closed rotary valve both on a test bench and on an actual vehicle. Test results demonstrated large improvements in straight line stability as well as steering feeling.


    Access

    Check access

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Center-Closed Rotary Servo Valve for Power Steering


    Additional title:

    Sae Technical Papers


    Contributors:

    Conference:

    International Congress & Exposition ; 1996



    Publication date :

    1996-02-01




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




    Center-closed rotary servo valve for power steering

    Fukumura,K. / Haga,K. / Suzuki,M. et al. | Automotive engineering | 1996


    Closed rotary cushion valve

    JIAO GUOWANG / ZHOU FEIPENG / DU JIANXI et al. | European Patent Office | 2023

    Free access

    Rotary valve of hydraulic power-assisted steering gear

    ZOU LIYAN / ZHANG ZHIFEN / HU XIANNENG et al. | European Patent Office | 2022

    Free access

    Two Dimensional Modeling of a Rotary Power Steering Valve

    Birsching, Joel E. | SAE Technical Papers | 1999


    Two Dimensional Modeling of a Rotary Power Steering Valve

    Birsching, J. E. / SAE | British Library Conference Proceedings | 1999