车辆制动装置VehicleBrakingDevice28课.pptx

车辆制动装置VehicleBrakingDevice120型控制阀MODEL120CONTROLVALVE主讲人李西安ZHENGZHOURAILWAYVOCATIONALTECHNICALCOLLEGESpeakerLiXi’an

制动保压位BrakingPressureMaintainingPosition（五）司机施行制动管常用制动减压，当制动管减压量达到要求时，将自动制动阀手把移到保压位，制动管停止减压呈保压状态。Driverusuallyreducespressurebyapplyingthebrakespipes.Whenthebraketubepressurereductionreachestherequirements,itwillmovetheautomaticbrakevalvehandtothepressureprotectionlevelandthebraketubestoppressurereductionisinthepressureprotectionstate.制动管刚停止减压时，作用部的主活塞、节制阀和滑阀仍处于制动位，副风缸压缩空气继续向制动缸充气使其压力降低。Whenthebrakepipejuststopsdecompression,themainpiston,controlvalveandslidevalveoftheactingpartarestillinthebrakepositionandtheauxiliaryaircylindercompressedaircontinuestoinflatethebrakecylindertoreducethepressure.当副风缸压力下降到接近制动管压力（实际上是副风缸压力稍低于制动管压力）时，主活塞在被压缩的稳定弹簧的弹力及自重作用下，主活塞带动节制阀下移6mm(滑阀不动)，至主活塞杆的上肩接触到滑阀上端面时为止，节制阀开放了滑阀背面的f1和f2孔，盖住滑阀背面的f3孔，形成了制动保压位。Whenthesecondaryaircylinderpressuredropstoclosetothebrakepipepressure(actuallythesecondaryaircylinderpressureslightlybelowthebrakepipepressure),themainpistoninthecompressionofthestablespringelasticityandweightandthemainpistondrivecontrolvalvedown6mm(slidevalve)tothemainpistonrodshouldercontacttheupperendoftheslidevalveandthecontrolvalveopenthebackoftheslideofthef1andf2holes,coverthef3holeonthebackofthespoolvalveandformthebrakepressurelevel.节制阀盖住滑阀背面的f3孔，切断了副风缸压力空气向制动缸的充气通路，副风缸停止降压，制动缸停止升压，滑阀仍处于制动位，实现制动保压作用。Thecontrolvalvecoversthef3holeonthebackoftheslidevalve,cuttingofftheairpressureofthesecondaryaircylindertothebrakecylinder.Thesecondaryaircylinderstopsthepressureandthebrakecylinderstopstheboostandtheslidevalveisstillinthebrakingpositiontorealizingthepressureprotectioneffectofthebrake.

制动保压位BrakingPressureMaintainingPosition（五）图7—30120阀制动保压位

紧急制动位Emergencybrakingpo