車輛制動(dòng)裝置VehicleBrakingDevice12課

車輛制動(dòng)裝置VehicleBrakingDevice任務(wù)五F8型分配閥MISSION5F8DISTRIBUTIONVALVE主講人李西安ZHENGZHOURAILWAYVOCATIONAL&TECHNICALCOLLEGESpeakerLiXi’an緊急制動(dòng)作用(Emergencybrakingfunction)五、緊急制動(dòng)作用(Emergencybrakingfunction)五、緊急制動(dòng)時(shí)，主控部的動(dòng)作與常用制動(dòng)時(shí)相同，只是由于制動(dòng)管的減壓速度比常用制動(dòng)時(shí)快，主控部的動(dòng)作更迅速。Duringemergencybraking,theoperationofthemaincontrolsectionisthesameasinregularbraking,exceptthatthepressurereductionspeedinthebrakepipeisfaster,resultinginamorerapidoperationofthemaincontrolsection.另外，主活塞上下兩側(cè)形成的壓力差也比常用制動(dòng)時(shí)大的多，所以平衡閥處于全開狀態(tài)，副風(fēng)缸的壓縮空氣迅速進(jìn)入制動(dòng)缸，制動(dòng)缸的壓力迅速上升。Additionally,thepressuredifferenceformedonbothsidesofthemainpistonduringemergencybrakingismuchlargerthaninregularbraking,sothebalancevalveisinafullyopenstate,thecompressedairfromtheauxiliarycylinderrapidlyentersthebrakecylinder,causingthebrakecylinderpressuretoriserapidly.此時(shí)，輔助室的壓縮空氣除經(jīng)常用制動(dòng)排風(fēng)堵排大氣外，輔助室與緊急排風(fēng)堵Ⅵ的聯(lián)絡(luò)通路也被打開，輔助室的壓縮空氣經(jīng)兩路同時(shí)排人大氣。Atthistime,inadditiontothecompressedairintheauxiliarychamberbeingexhaustedtotheatmospherethroughregularbrakeventing,thecommunicationpassagebetweentheauxiliarychamberandtheemergencyventingplugVIisalsoopened,thecompressedairintheauxiliarychamberisexhaustedtotheatmospherethroughbothpathssimultaneously.同時(shí)，由于制動(dòng)管緊急減壓，輔助閥活塞下方的空氣壓力驟降，輔助閥活塞的上下兩側(cè)形成較大的壓力差，輔助閥活塞迅速向下移動(dòng)，輔助閥桿壓縮放風(fēng)閥彈簧，頂開緊急放風(fēng)閥，使制動(dòng)管的壓縮空氣從放風(fēng)閥迅速排人大氣，達(dá)到緊急排風(fēng)的目的。Atthesametime,duetotheemergencypressurereductioninthebrakepipe,theairpressurebelowtheauxiliaryvalvepistondropssuddenly,resultinginalargepressuredifferenceonbothsidesoftheauxiliaryvalvepiston.Theauxiliaryvalvepistonquicklymovesdownward,compressingthespringoftheexhaustvalve,pushingopentheemergencyexhaustvalveandallowingthecompressedairinthebrakepipetoquicklyexhausttotheatmosphere,achievingthepurposeofemergencyventing.緊急制動(dòng)作用(Emergencybrakingfunction)五、當(dāng)制動(dòng)缸空氣壓力超過限壓閥彈簧的預(yù)緊力時(shí)，限壓閥向上移動(dòng)，關(guān)閉副風(fēng)缸向制動(dòng)缸的充氣通路，此時(shí)，雖然主閥處于緊急制動(dòng)狀態(tài)，但制動(dòng)缸的空氣壓力不能繼續(xù)上升，制動(dòng)缸的最高壓力值受限壓閥的控制。Whenthebrakecylinderairpressureexceedsthepre-tighteningforceofthepressure-limitingvalvespring,thepressurelimitingvalvemovesupward,closingtheairsupplypassagefromtheauxiliarycylindertothebrakecylinder.Atthistime,althoughthemainvalveisinthestateofemergencybraking,theairpressureinthebrakecylindercannotcontinuetorise,asthemaximumpressureinthebrakecylinderiscontrolledbythepressurelimitingvalve.緊急制動(dòng)時(shí)，制動(dòng)管的空氣壓力迅速降至0后，輔助室的壓縮空氣繼續(xù)由兩排人大氣，大約需經(jīng)10-15s降至0，在此過程中，放風(fēng)閥一直處于開放狀態(tài)，制動(dòng)管無法施行再充氣。Duringemergencybraking,whentheairpressureinthebrakepiperapidlydropstozero,thecompressedairintheauxiliarychambercontinuestobeventedtotheatmospherethroughtwopassages.Thisprocesstakesapproximately10-15secondsforthepressuretodecreasetozero.Thereleasevalveremainsopenthroughoutthisprocess,preventingthebrakepipefrombeingrecharged.限壓閥的限壓值可根據(jù)不同的要求進(jìn)行調(diào)整。Thepressurelimitingvalueofthepressurelimitingvalvecanbeadjustedaccordingtodifferentrequirements.因此，F(xiàn)8型制動(dòng)機(jī)在緊急制動(dòng)后，必須保持15s以后，才能施行充氣緩解作用。Consequently,theF8typebrakesystemrequiresaminimumof15secondsafteremergencybrak