车辆制动装置VehicleBrakingDevice30课.pptx

车辆制动装置VehicleBrakingDevice任务五F8型分配阀TypeF8distributionvalve主讲人李西安ZHENGZHOURAILWAYVOCATIONALTECHNICALCOLLEGESpeakerLiXi’an

F8型分配阀的作用（EffectsofF8typedistributingvalve）三2．常用制动作用及稳定性和安定性servicebrakingandstability

F8型分配阀的作用（EffectsofF8typedistributingvalve）三主控部处于制动位置。Thecontrolunitisinthebrakingposition.此时，由于缓解柱塞向上移动，切断压力风缸压缩空气向制动管逆流的通路，使主活塞上下两侧的压力差进一步增大，主活塞迅速向上移动。Atthispoint,asthereleaseplungermovesupward,itcutsoffthepathforcompressedairinthepressurechambertoflowbacktothebrakepipe,furtherincreasingthepressuredifferencebetweentheupperandlowersidesofthemainpiston.Themainpistonmovesrapidlyupward.缓解阀在弹簧的作用下，关闭制动缸与大气的通路。Undertheactionofthereleasevalvespring,thecommunicationbetweenthebrakecylinderandtheatmosphereisclosed.当制动管以常用制动减压时，主控部的主活塞上方的空气压力下降，而主活塞下方压力风缸压缩空气，开始向制动管逆流，Whenthebrakepipeisdepressurizedinservicebrakeapplication,theairpressureabovethemaincontrolpistoninthecontrolunitdecreases,whilethecompressedairbelowthemainpistoninthecontrolunitstartstoflowbacktothebrakepipe.但由于受缩堵Ⅰ的限制，其逆流速度较慢，However,duetotherestrictionofrestrictorI,theflowrateintheoppositedirectionisslow.随之主活塞上下形成一定的压力差，同时又有制动弹簧的预紧力作用，推动主活塞并带动缓解柱塞、主阀杆等向上移动。Asaresult,apressuredifferenceisformedbetweentheupperandlowersidesofthemainpistonandthepre-tensionforceofthebrakespringpushesthemainpiston,alongwiththereleaseplungerandthemainvalvestem,upwards.

F8型分配阀的作用（EffectsofF8typedistributingvalve）三第一阶段局减作用First-stagelocalreduction：主活塞上方的压缩空气经a3→缓解柱塞中心孔a4→缓解柱塞径向孔→缓解柱塞与局减阀套的沟槽→e5→局减阀中的缩堵Ⅳ→e4→e3→e2→e1→e→局减室，同时经通路e3→充气阀排气口排人大气，形成第一阶段局减作用Thecompressedairabovethemainpistongoesthrougha3→thecenterholea4ofthereleaseplunger→theradialholeofthereleaseplunger→thegroovebetweenthereleaseplungerandthelocalreductionvalveseat→e5→therestrictorIV