车辆制动装置VehicleBrakingDevice08课

车辆制动装置VehicleBrakingDevice任务六120型控制阀Mission6120controlvalve主讲人李西安ZHENGZHOURAILWAYVOCATIONAL&TECHNICALCOLLEGESpeakerLiXi’an制动保压作用及自动补风作用（Brakingpressuremaintainingfunctionandautomaticairreplenishmentfunction）3.制动保压作用及自动补风作用（Brakingpressuremaintainingfunctionandautomaticairreplenishmentfunction）3.

制动保压作用（Brakingpressuremaintaining

function）（1）在常用制动过程中，制动管停止减压后，副风缸的压缩空气继续进入制动缸及小活塞上方空间，Intheregularbrakingprocess,afterthepressurereductioninthebrakepipestops,thecompressedairfromtheauxiliarycylindercontinuestoenterthebrakecylinderandthespaceabovethesmallpiston.当作用在主阀上向下的作用力大于向上的作用力时，主阀小活塞和主活塞一起向下移，平衡阀关闭，Intheregularbrakingprocess,afterthepressurereductioninthebrakepipestops,thecompressedairfromtheauxiliarycylindercontinuestoenterthebrakecylinderandthespaceabovethesmallpiston.此时副风缸向制动缸的充气通路被切断，副风缸停止向制动缸供气。Atthistime,theairsupplyfromtheauxiliarycylindertothebrakecylinderiscutoff,theauxiliarycylinderstopssupplyingairtothebrakecylinder.主阀的其他通路与常用制动时相同，主阀处于制动保压位。Atthistime,theairsupplyfromtheauxiliarycylindertothebrakecylinderiscutoff,theauxiliarycylinderstopssupplyingairtothebrakecylinder.制动管停止减压后，辅助室的压缩空气继续排人大气，Afterthepressurereductioninthebrakepipestops,thecompressedairintheauxiliarychambercontinuestoexhausttotheatmosphere.当辅助阀活塞上侧的压力低于下侧压力时，辅助阀活塞带动辅助阀杆向上移动，关闭辅助室与大气的通路，Whenthepressureontheuppersideoftheauxiliaryvalvepistonislowerthanthepressureonthelowerside,theauxiliaryvalvepistondrivestheauxiliaryvalverodtomoveupward,closingthepassagebetweentheauxiliarychamberandtheatmosphere.辅助室停止排气，辅助阀也处于保压位状态。Theexhaustfromtheauxiliarychamberstopsandtheauxiliaryvalveisalsointhepressuremaintainingposition.制动保压作用及自动补风作用（Brakingpressuremaintainingfunctionandautomaticairreplenishmentfunction）3.

自动补风作用（Theexhaustfromtheauxiliarychamber）

（2）制动保压位，主控部三压力机构处于平衡状态，即制动管压力与制动缸压力作用在主活塞与小活塞上向下的压力与压力风缸作用在主活塞上向上的压力平衡。Inthebrakingpressuremaintainingposition,thethree-pressuremechanismofthemaincontrolsectionisinabalancedstate,thatis,thedownwardforceexertedbythebrakepipepressureandthebrakecylinderpressureonthemainpistonandthesmallpistonisbalancedwiththeupwardforceexertedbythepressurechamberonthemainpiston.长大下坡道运行因制动时间长，闸瓦磨耗引起制动缸活塞行程伸长，使得制动缸容积增大或因制动缸漏泄，均会引起制动缸压力下降，则反映在小活塞上侧压力下降，

Duringlongdownhilloperation,duetoprolongedbraking,thebrakecylinderpistonstrokebecomeslongerduetobrakeliningwear,resultinginanincreaseinbrakecylindervolume,orduetobrakecylinderleakage,whichwillcauseadecreaseinbrakecylinderpressure.主控部三压力机构失去保压位的平衡，机构向上的力大于向下的力，主活塞和小活塞上移，主阀杆再次推开平衡阀，使副风缸向制动缸和小活塞上方充气。

Thisdecreaseisreflectedinadecreaseinpressureontheuppersideofthesmallpiston,thethree-pressuremechanismofthemaincontrolsectionlosesthebalancedpressuremaintainingpositionandtheupwardforceisgreaterthanthedownwardforceinthemechanism,causingthemainpistonandthesmallpistontomoveupward,themainvalvestempushesopenthebalancevalveagain,allowingtheauxiliarycylindertosupplyairtothebrakecylinderandthespaceabovethesmallpiston.当制动缸恢复到原平衡压力时，主活塞和小活塞下移，平衡阀再一次关闭，停止副风缸向制动缸补送压力空气。

Whenthebrakecylinderpressurereturnstotheoriginalbalancedpressure,themainpistonandthesmallpistonmovedownward,thebalancevalveclosesagainandtheairsupplyfromtheauxiliarycylindertothebrakecylinderstops.这一过程即自动补风作用，保证实现了制动力不衰减的性能。分配阀的这一性能，适应于长大下坡道运行。

Thisprocessiscalledautomaticairreplenishment,whichensuresthatthebrakingforcedoesnotdecrease.Thisfeatureofthedistributionvalveissuitableforlongdownhilloperations.阶段缓解保压作用（Stagereleasepressuremaintainingfunction）4.阶段缓解保压作用（Stagereleasepressuremaintainingfunction）4.当转换盖板装于阶段缓解位置时，F8型分配阀具有阶段缓解作用，就是在充气缓解时制动管停止增压，制动缸压力也相应地停止向大气排气，实现制动机的阶段性缓解动作。Whenthetransitioncoverplateisinthestagereleaseposition,theF8typedistributingvalvehasastagereleasefunction,whichmeansthatduringtheairreleaseprocess,thepressurizedairsupplytothebrakepipestopsandthebrakecylinderpressurealsostopsexhaustingtotheatmosphere,achievingthestagereleaseactionofthebrakingsystem.在转换盖板阶段缓解位，由于转换盖板切断了压力风缸与制动管的直接联络通路，主控部处于缓解位时，压力风缸的压缩空气就不能直接向制动管逆流，其空气压力基本保持不变。

Whenthetransitioncoverplateisinthestagereleaseposition,asitcutsoffthedirectconnectionbetweenthepressurechamberandthebrakepipe,whenthemaincontrolsectionisinthereleaseposition,thecompressedairinthepressurechambercannotdirectlyflowbacktothebrakepipeanditsairpressureremainsbasicallyunchanged.当制动管停止增压，而作用在小活塞上方的制动缸压力与作用在主活塞上方的制动管压力的合力小于压力风缸空气向上的作用力时，主活塞向上移动，使制动管、制动缸和压力风缸三者压力维持平衡状态。

Whenthepressuresupplytothebrakepipestopsandthecombinedforceofthebrakecylinderpressureactingontheuppersideofthesmallpistonandthebrakepipepressureactingontheuppersideofthemainpistonislessthantheupwardforceofthepressurechamber,themainpistonmovesupward,maintainingthebalanceofpressureamongthebrakepipe,thebrakecylinderandthepressurechamber.此时，主活塞带动缓解柱塞向上移动，缓解阀关闭，切断了制动缸向大气的排气通路，F8型分配阀的主阀从充气缓解状态进入阶段缓解保压位。

Atthistime,themainpistondrivesthereleaseplungertomoveupward,closingthereleasevalveandcuttingofftheexhaustpassagefromthebrakecylindertotheatmosphere.ThemainvalveoftheF8typedistributionvalveentersthestagereleasepressuremaintainingpositionfromtheairreleaseposition.阶段缓解保压作用（Stagereleasepressuremaintainingfunction）4.在制动缸空气压力降至20kPa以下，充气阀在其弹簧作用下向上移动，充气阀杆重新沟通压力风缸与制动管的联络通路，压力风缸的压缩空气先向制动管逆流，等压力风缸空气压力小于制动管空气压力后，制动管向压力风缸充气。Onlywhenthebrakecylinderairpressuredropsbelow20kPa,theinflationvalvemovesupwardundertheactionofitsspring,reconnectingthecommunicationpassagebetweenthepressurechamberandthebrakepipeandthecompressedairinthepressurechamberflowsbacktothebrakepipe,whentheairpressureinthepressurechamberislowerthantheairpressureinthebrakepipe,thebrakepipestartstobeinflated.

阶段缓解保压位（Stagereleasepressuremaintaining

position）是在充气缓解作用后施行的制动管保压状态isthebrakepipepressuremaintainingstateimplementedaftertheairreleaseaction.所以缓解柱塞、主活塞、主活塞杆等都处于下方位置（即缓解阀刚关闭的位置）Therefore,thereleaseplunger,mainpiston,mainpistonrod,etc.,areallinthedownwardposition(i.e.,justclosed