汽車制動總泵的作用
剎車總泵是汽車(che)(che)行車(che)(che)剎(cha)車(che)(che)系(xi)統(tong)當中(zhong)的主(zhu)要控制裝置,在雙(shuang)回路(lu)主(zhu)制動系(xi)統(tong)的制動過程和釋放過程中(zhong)實現靈(ling)敏的隨(sui)動控制。
汽車制動總泵結構
總泵通(tong)(tong)常是由(you)缸(gang)體、活塞、活塞回位彈簧、復式(shi)閥(fa)(油液(ye)控制閥(fa))、皮碗(wan)(wan)、皮圈等部(bu)分組成。缸(gang)體上下分貯(zhu)液(ye)室(shi)、工(gong)作缸(gang)室(shi),活塞從(cong)缸(gang)體的(de)后(hou)(hou)端裝(zhuang)(zhuang)進(jin)缸(gang)內,將(jiang)缸(gang)體分為前、后(hou)(hou)兩(liang)室(shi),皮碗(wan)(wan)前的(de)前工(gong)作缸(gang)通(tong)(tong)向(xiang)貯(zhu)液(ye)室(shi)的(de)小孔為回油孔,皮圈前、活塞頂部(bu)之后(hou)(hou)的(de)后(hou)(hou)工(gong)作缸(gang)通(tong)(tong)向(xiang)貯(zhu)掖(ye)室(shi)的(de)大孔為進(jin)液(ye)孔(補償孔)。總泵安裝(zhuang)(zhuang)位置(zhi)都以活塞進(jin)口處為后(hou)(hou)。
汽車制動總泵工作原理
當踩下制動(dong)踏板(ban)時,推(tui)(tui)桿向前推(tui)(tui)動(dong)總(zong)泵活(huo)塞(sai),在皮碗(wan)遮(zhe)閉回油孔后,活(huo)塞(sai)前室油液壓(ya)力增高,復式閥(fa)門中間的出(chu)油閥(fa)被壓(ya)開,油液經過管(guan)路(lu)流向各制動(dong)車(che)輪分泵缸。油液推(tui)(tui)動(dong)分泵活(huo)塞(sai),克服制動(dong)蹄回位彈簧的拉力而(er)推(tui)(tui)開制動(dong)蹄.蹄片壓(ya)緊制動(dong)鼓,產(chan)生制動(dong)作用。
當駕駛者(zhe)踩下制(zhi)(zhi)動踏板并(bing)保(bao)持不(bu)動時,總泵(beng)前工(gong)作室及分(fen)泵(beng)缸(gang)內(nei)油(you)壓不(bu)再(zai)增加(jia),出油(you)閥(fa)在彈簧的(de)作用下關(guan)閉(bi),回油(you)閥(fa)也是關(guan)閉(bi)的(de),復式閥(fa)門處于(yu)雙關(guan)閉(bi)狀態(tai),總泵(beng)缸(gang)不(bu)再(zai)向車輪分(fen)泵(beng)缸(gang)供油(you),分(fen)泵(beng)缸(gang)內(nei)的(de)油(you)液也不(bu)能(neng)回流(liu),整個管路處于(yu)等壓,制(zhi)(zhi)動系維持一定的(de)制(zhi)(zhi)動強度。
放松制(zhi)(zhi)動(dong)(dong)踏板時,在(zai)踏板回(hui)位彈(dan)簧和活(huo)(huo)塞(sai)回(hui)位彈(dan)贊的作用(yong)下(xia),總泵(beng)(beng)活(huo)(huo)塞(sai)向后(hou)退,總泵(beng)(beng)缸(gang)(gang)前(qian)工作室(shi)油(you)(you)壓(ya)(ya)降低,分泵(beng)(beng)缸(gang)(gang)內(nei)高壓(ya)(ya)油(you)(you)液壓(ya)(ya)開(kai)復式(shi)閥(fa)門口外的回(hui)油(you)(you)閥(fa)流回(hui)總泵(beng)(beng)前(qian)室(shi)。隨著(zhu)制(zhi)(zhi)動(dong)(dong)液的流回(hui),制(zhi)(zhi)動(dong)(dong)蹄在(zai)其回(hui)位彈(dan)簧的拉力(li)(li)下(xia)合攏,制(zhi)(zhi)動(dong)(dong)狀態解除(chu)。由(you)于(yu)總泵(beng)(beng)活(huo)(huo)塞(sai)回(hui)位彈(dan)簧在(zai)裝配狀態下(xia)就有一定(ding)的預(yu)壓(ya)(ya)力(li)(li),當油(you)(you)液回(hui)流油(you)(you)壓(ya)(ya)降低到不能克(ke)服預(yu)壓(ya)(ya)力(li)(li)時,回(hui)油(you)(you)閥(fa)又關閉,制(zhi)(zhi)動(dong)(dong)液停止流回(hui),于(yu)是(shi)管(guan)道及(ji)(ji)分泵(beng)(beng)缸(gang)(gang)內(nei)油(you)(you)壓(ya)(ya)比總泵(beng)(beng)缸(gang)(gang)內(nei)油(you)(you)壓(ya)(ya)高出(chu)約0.5公(gong)斤(jin)/平方(fang)厘米。這(zhe)就是(shi)所謂(wei)分泵(beng)(beng)缸(gang)(gang)及(ji)(ji)管(guan)道中(zhong)的殘余(yu)壓(ya)(ya)力(li)(li),這(zhe)個(ge)殘余(yu)壓(ya)(ya)力(li)(li)可以為(wei)下(xia)次制(zhi)(zhi)動(dong)(dong)的迅速(su)實現提供(gong)條件。
當迅(xun)(xun)(xun)速放松制(zhi)動(dong)(dong)(dong)踏(ta)板時(shi),總泵(beng)活(huo)塞在(zai)回位彈簧作用下(xia)迅(xun)(xun)(xun)速后(hou)退,總泵(beng)缸(gang)(gang)的(de)前(qian)工(gong)(gong)作室(shi)(shi)內容積擴大,油壓(ya)(ya)迅(xun)(xun)(xun)速降低,各分泵(beng)缸(gang)(gang)內油液受管道阻力的(de)影(ying)響,來不及(ji)流回并充滿活(huo)塞前(qian)工(gong)(gong)作室(shi)(shi),活(huo)塞前(qian)工(gong)(gong)作室(shi)(shi)會(hui)出現(xian)負壓(ya)(ya),而活(huo)塞后(hou)工(gong)(gong)作室(shi)(shi)油壓(ya)(ya)相對(dui)較(jiao)高。在(zai)此壓(ya)(ya)力差(cha)的(de)作用下(xia),貯液室(shi)(shi)內的(de)油液便(bian)經(jing)進液大孔、活(huo)塞后(hou)室(shi)(shi)、活(huo)塞頂部的(de)六個小孔,翻過皮碗的(de)邊緣(yuan)流入活(huo)塞前(qian)工(gong)(gong)作室(shi)(shi)。此時(shi)再踩下(xia)制(zhi)動(dong)(dong)(dong)踏(ta)板,又會(hui)有制(zhi)動(dong)(dong)(dong)液供給(gei)各分泵(beng)缸(gang)(gang),以增強制(zhi)動(dong)(dong)(dong)效(xiao)率。踩一腳制(zhi)動(dong)(dong)(dong)感覺到制(zhi)動(dong)(dong)(dong)力不足時(shi),二腳制(zhi)動(dong)(dong)(dong)便(bian)會(hui)生效(xiao)。
汽車制動總泵常見故障診斷
1、剎車偏軟
汽(qi)車(che)行駛中制(zhi)(zhi)(zhi)動(dong)(dong)時,制(zhi)(zhi)(zhi)動(dong)(dong)減速度小,制(zhi)(zhi)(zhi)動(dong)(dong)距離長,液壓制(zhi)(zhi)(zhi)動(dong)(dong)系統(tong)產(chan)生制(zhi)(zhi)(zhi)動(dong)(dong)效能(neng)不(bu)(bu)良(liang)(liang)的(de)原因,一般(ban)可(ke)(ke)根據(ju)制(zhi)(zhi)(zhi)動(dong)(dong)踏(ta)(ta)板(ban)行程(cheng)、踏(ta)(ta)制(zhi)(zhi)(zhi)動(dong)(dong)踏(ta)(ta)板(ban)時的(de)軟硬感覺、踏(ta)(ta)下制(zhi)(zhi)(zhi)動(dong)(dong)踏(ta)(ta)板(ban)后的(de)穩(wen)定(ding)性(xing)(xing)來判(pan)斷。維持制(zhi)(zhi)(zhi)動(dong)(dong)時,踏(ta)(ta)板(ban)的(de)高度若緩慢下降,說明制(zhi)(zhi)(zhi)動(dong)(dong)管路某處(chu)破裂、接頭密閉不(bu)(bu)良(liang)(liang)、總泵或(huo)分泵活塞密封不(bu)(bu)良(liang)(liang)、回油閥及(ji)出(chu)油閥不(bu)(bu)良(liang)(liang)。可(ke)(ke)首(shou)先踏(ta)(ta)下制(zhi)(zhi)(zhi)動(dong)(dong)踏(ta)(ta)板(ban),觀(guan)察有無制(zhi)(zhi)(zhi)動(dong)(dong)液滲(shen)漏部位。若外部正常,則(ze)應檢(jian)查分泵或(huo)總泵故(gu)障。連續(xu)幾(ji)腳(jiao)制(zhi)(zhi)(zhi)動(dong)(dong)時踏(ta)(ta)板(ban)高度稍有增高,并有彈性(xing)(xing)感,說明制(zhi)(zhi)(zhi)動(dong)(dong)管路中滲(shen)入了空氣。
2、剎車跑偏
剎車(che)時,方(fang)向跑偏,特別是沒有(you)裝ABS剎車(che)防抱死裝置的汽車(che),方(fang)向控制不了,其原因為(wei)剎車(che)磨損不均(jun),總泵一(yi)個(ge)活塞油封膨脹、一(yi)個(ge)分泵漏(lou)油所致。
3、剎車抖動
剎車時(shi)擺振,方向盤(pan)彈手。原因(yin)為剎車盤(pan)擺差超限,剎車鉗變形,剎車片磨成錐(zhui)形。發生此類情況必須進廠檢(jian)修(xiu)。
4、剎車吱吱響
一般為剎車盤、片或制(zhi)動鼓、蹄片磨損不平所致。
5、剎車突然失靈
汽車在行駛中,一腳或連續幾腳剎車,剎車均被踏到底,剎車突然失靈。原因:制動總泵或分泵漏油嚴重;制(zhi)(zhi)動總(zong)泵或分泵活塞密(mi)封圈破損(sun),或剎車油路中(zhong)有(you)過多的(de)空氣。如發生此情況(kuang),司機應(ying)迅速連續(xu)兩腳剎車。發生制(zhi)(zhi)動失(shi)靈的(de)故障,應(ying)立即停車檢查。首先觀察制(zhi)(zhi)動液(ye)罐中(zhong)的(de)制(zhi)(zhi)動液(ye)有(you)無虧(kui)損(sun),然后(hou)觀察制(zhi)(zhi)動總(zong)泵、分泵、油管(guan)有(you)無泄漏制(zhi)(zhi)動液(ye)處。
6、剎車不回
踏(ta)下制(zhi)(zhi)動踏(ta)板(ban)時感到(dao)既高(gao)(gao)又硬或(huo)沒有自由(you)行程(cheng),汽車起步(bu)困難或(huo)行駛費力。故障現象:踩剎(cha)車踏(ta)板(ban),踏(ta)板(ban)不(bu)升(sheng)高(gao)(gao),無阻力。需(xu)判(pan)斷制(zhi)(zhi)動液是否(fou)缺失(shi);制(zhi)(zhi)動分(fen)泵、管路及(ji)接頭(tou)處是否(fou)漏油;總泵、分(fen)泵零部件是否(fou)損壞。