1、液壓密(mi)封件(jian)之(zhi)形式選擇

　　在(zai)液壓(ya)系統中，常(chang)見(jian)的(de)密(mi)封(feng)(feng)形(xing)(xing)式(shi)有(you)擠(ji)壓(ya)型O形(xing)(xing)密(mi)封(feng)(feng)圈、Y形(xing)(xing)圈、V形(xing)(xing)圈、U形(xing)(xing)圈唇形(xing)(xing)密(mi)封(feng)(feng)。唇形(xing)(xing)密(mi)封(feng)(feng)圈主(zhu)要用(yong)(yong)于往復動(dong)密(mi)封(feng)(feng)，與O形(xing)(xing)圈等擠(ji)壓(ya)密(mi)封(feng)(feng)相(xiang)比，往復動(dong)密(mi)封(feng)(feng)使用(yong)(yong)唇形(xing)(xing)密(mi)封(feng)(feng)圈具(ju)有(you)更好(hao)的(de)綜合性能和更長(chang)的(de)使用(yong)(yong)壽命(ming)。

　　唇(chun)(chun)形密(mi)(mi)封(feng)圈(quan)(quan)的(de)(de)密(mi)(mi)封(feng)壓(ya)(ya)(ya)(ya)(ya)(ya)緊力(li)(li)是隨介(jie)質(zhi)壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)(li)的(de)(de)改變(bian)而變(bian)化的(de)(de)，工作(zuo)中始終(zhong)應(ying)監控介(jie)質(zhi)壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)(li)的(de)(de)變(bian)化，即能保(bao)(bao)證足夠的(de)(de)密(mi)(mi)封(feng)壓(ya)(ya)(ya)(ya)(ya)(ya)緊力(li)(li)，又不(bu)至于產(chan)生過(guo)大的(de)(de)摩(mo)擦(ca)(ca)力(li)(li)，擠壓(ya)(ya)(ya)(ya)(ya)(ya)性(xing)(xing)密(mi)(mi)封(feng)主(zhu)要(yao)靠預(yu)壓(ya)(ya)(ya)(ya)(ya)(ya)緊力(li)(li)產(chan)生密(mi)(mi)封(feng)力(li)(li)，密(mi)(mi)封(feng)圈(quan)(quan)接(jie)觸(chu)壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)(li)預(yu)先(xian)給定，工作(zuo)中不(bu)能根(gen)據(ju)介(jie)質(zhi)壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)(li)的(de)(de)改變(bian)而變(bian)化。大的(de)(de)預(yu)壓(ya)(ya)(ya)(ya)(ya)(ya)力(li)(li)會(hui)使密(mi)(mi)封(feng)圈(quan)(quan)與(yu)密(mi)(mi)封(feng)面接(jie)觸(chu)面積增(zeng)大，產(chan)生很大的(de)(de)摩(mo)擦(ca)(ca)阻力(li)(li)，過(guo)大的(de)(de)摩(mo)擦(ca)(ca)力(li)(li)會(hui)造成(cheng)密(mi)(mi)封(feng)圈(quan)(quan)的(de)(de)破損，在(zai)低壓(ya)(ya)(ya)(ya)(ya)(ya)時造成(cheng)啟動困難(nan)，或產(chan)生爬(pa)行現象(xiang)，唇(chun)(chun)形密(mi)(mi)封(feng)圈(quan)(quan)可以通過(guo)唇(chun)(chun)部撐(cheng)開(kai)，變(bian)形補償(chang)小(xiao)的(de)(de)磨損量(liang)，保(bao)(bao)證密(mi)(mi)封(feng)效(xiao)果(guo)和(he)密(mi)(mi)封(feng)壽命;而O形圈(quan)(quan)隨著摩(mo)擦(ca)(ca)余量(liang)的(de)(de)減少(shao)，直接(jie)影響其(qi)密(mi)(mi)封(feng)性(xing)(xing)。

　　2、液壓(ya)密封件(jian)之材(cai)料(liao)選擇(ze)

　　密(mi)(mi)封(feng)件形式和結構現(xian)(xian)在一(yi)(yi)般(ban)已經(jing)定型(xing)，各(ge)密(mi)(mi)封(feng)件質量(liang)區(qu)別主要在于制作材料(liao)上。密(mi)(mi)封(feng)材料(liao)主要使(shi)(shi)用(yong)(yong)橡膠(jiao)和合(he)成樹脂(zhi)。由于各(ge)種材料(liao)性(xing)能(neng)特(te)點不(bu)同(tong)(tong)，性(xing)能(neng)特(te)點不(bu)同(tong)(tong)，用(yong)(yong)途也就有(you)(you)(you)(you)(you)所不(bu)同(tong)(tong)。選用(yong)(yong)時需(xu)根據不(bu)同(tong)(tong)的(de)使(shi)(shi)用(yong)(yong)條件和不(bu)同(tong)(tong)的(de)使(shi)(shi)用(yong)(yong)條件作出合(he)適的(de)選擇。另外，某(mou)一(yi)(yi)材質的(de)密(mi)(mi)封(feng)對被密(mi)(mi)封(feng)的(de)某(mou)一(yi)(yi)工作介質(如礦物(wu)油等(deng))表(biao)現(xian)(xian)較好的(de)密(mi)(mi)封(feng)性(xing)能(neng)，而對另一(yi)(yi)介質表(biao)現(xian)(xian)極(ji)差，這就是密(mi)(mi)封(feng)材料(liao)與(yu)液(ye)壓(ya)油的(de)相容性(xing)。還有(you)(you)(you)(you)(you)，各(ge)種不(bu)同(tong)(tong)的(de)密(mi)(mi)封(feng)材料(liao)對你(ni)不(bu)同(tong)(tong)的(de)工作條件表(biao)現(xian)(xian)出不(bu)同(tong)(tong)的(de)性(xing)能(neng)。有(you)(you)(you)(you)(you)些(xie)(xie)(xie)(xie)耐(nai)(nai)(nai)熱，有(you)(you)(you)(you)(you)些(xie)(xie)(xie)(xie)不(bu)耐(nai)(nai)(nai)熱;有(you)(you)(you)(you)(you)些(xie)(xie)(xie)(xie)耐(nai)(nai)(nai)酸，有(you)(you)(you)(you)(you)些(xie)(xie)(xie)(xie)耐(nai)(nai)(nai)堿，有(you)(you)(you)(you)(you)些(xie)(xie)(xie)(xie)耐(nai)(nai)(nai)水，有(you)(you)(you)(you)(you)些(xie)(xie)(xie)(xie)耐(nai)(nai)(nai)油;有(you)(you)(you)(you)(you)些(xie)(xie)(xie)(xie)抗熱，有(you)(you)(you)(you)(you)些(xie)(xie)(xie)(xie)耐(nai)(nai)(nai)低溫，有(you)(you)(you)(you)(you)些(xie)(xie)(xie)(xie)耐(nai)(nai)(nai)高溫，等(deng)等(deng)。這些(xie)(xie)(xie)(xie)因素在考慮密(mi)(mi)封(feng)件材料(liao)的(de)時候需(xu)注意。