1、液(ye)壓密封件之(zhi)形式(shi)選擇(ze)

　　在液壓系統中，常見的(de)密封(feng)形(xing)式(shi)有擠壓型O形(xing)密封(feng)圈(quan)(quan)、Y形(xing)圈(quan)(quan)、V形(xing)圈(quan)(quan)、U形(xing)圈(quan)(quan)唇形(xing)密封(feng)。唇形(xing)密封(feng)圈(quan)(quan)主要用于(yu)往(wang)復(fu)動(dong)密封(feng)，與O形(xing)圈(quan)(quan)等擠壓密封(feng)相比，往(wang)復(fu)動(dong)密封(feng)使(shi)用唇形(xing)密封(feng)圈(quan)(quan)具有更好(hao)的(de)綜合性能和更長的(de)使(shi)用壽命。

　　唇(chun)(chun)形(xing)密(mi)(mi)封(feng)(feng)(feng)圈(quan)(quan)的(de)(de)密(mi)(mi)封(feng)(feng)(feng)壓(ya)(ya)(ya)(ya)緊力(li)(li)(li)是隨介(jie)質壓(ya)(ya)(ya)(ya)力(li)(li)(li)的(de)(de)改變(bian)(bian)而變(bian)(bian)化的(de)(de)，工作(zuo)中始終(zhong)應監控介(jie)質壓(ya)(ya)(ya)(ya)力(li)(li)(li)的(de)(de)變(bian)(bian)化，即能保證足夠的(de)(de)密(mi)(mi)封(feng)(feng)(feng)壓(ya)(ya)(ya)(ya)緊力(li)(li)(li)，又不至于產生(sheng)過(guo)大的(de)(de)摩擦(ca)力(li)(li)(li)，擠壓(ya)(ya)(ya)(ya)性(xing)密(mi)(mi)封(feng)(feng)(feng)主要靠預(yu)壓(ya)(ya)(ya)(ya)緊力(li)(li)(li)產生(sheng)密(mi)(mi)封(feng)(feng)(feng)力(li)(li)(li)，密(mi)(mi)封(feng)(feng)(feng)圈(quan)(quan)接觸壓(ya)(ya)(ya)(ya)力(li)(li)(li)預(yu)先給定，工作(zuo)中不能根據介(jie)質壓(ya)(ya)(ya)(ya)力(li)(li)(li)的(de)(de)改變(bian)(bian)而變(bian)(bian)化。大的(de)(de)預(yu)壓(ya)(ya)(ya)(ya)力(li)(li)(li)會使密(mi)(mi)封(feng)(feng)(feng)圈(quan)(quan)與密(mi)(mi)封(feng)(feng)(feng)面接觸面積增大，產生(sheng)很(hen)大的(de)(de)摩擦(ca)阻力(li)(li)(li)，過(guo)大的(de)(de)摩擦(ca)力(li)(li)(li)會造成密(mi)(mi)封(feng)(feng)(feng)圈(quan)(quan)的(de)(de)破(po)損，在低壓(ya)(ya)(ya)(ya)時造成啟動困難，或產生(sheng)爬行現象，唇(chun)(chun)形(xing)密(mi)(mi)封(feng)(feng)(feng)圈(quan)(quan)可以通過(guo)唇(chun)(chun)部(bu)撐開，變(bian)(bian)形(xing)補(bu)償小的(de)(de)磨(mo)損量，保證密(mi)(mi)封(feng)(feng)(feng)效果(guo)和密(mi)(mi)封(feng)(feng)(feng)壽命;而O形(xing)圈(quan)(quan)隨著摩擦(ca)余(yu)量的(de)(de)減少，直接影響其密(mi)(mi)封(feng)(feng)(feng)性(xing)。

　　2、液壓(ya)密(mi)封件之材(cai)料選擇

　　密(mi)(mi)封(feng)(feng)件形式和(he)結構現(xian)在(zai)(zai)一般已經定型，各密(mi)(mi)封(feng)(feng)件質(zhi)量區別主要在(zai)(zai)于(yu)制作(zuo)材(cai)料(liao)上。密(mi)(mi)封(feng)(feng)材(cai)料(liao)主要使用(yong)(yong)橡膠(jiao)和(he)合成樹脂(zhi)。由于(yu)各種材(cai)料(liao)性(xing)能(neng)特點不(bu)同(tong)(tong)(tong)(tong)，性(xing)能(neng)特點不(bu)同(tong)(tong)(tong)(tong)，用(yong)(yong)途也就有(you)所不(bu)同(tong)(tong)(tong)(tong)。選用(yong)(yong)時需(xu)根據不(bu)同(tong)(tong)(tong)(tong)的使用(yong)(yong)條(tiao)件和(he)不(bu)同(tong)(tong)(tong)(tong)的使用(yong)(yong)條(tiao)件作(zuo)出(chu)合適的選擇。另外，某一材(cai)質(zhi)的密(mi)(mi)封(feng)(feng)對(dui)被密(mi)(mi)封(feng)(feng)的某一工作(zuo)介質(zhi)(如(ru)礦(kuang)物油(you)等)表(biao)現(xian)較(jiao)好的密(mi)(mi)封(feng)(feng)性(xing)能(neng)，而對(dui)另一介質(zhi)表(biao)現(xian)極差，這(zhe)就是(shi)密(mi)(mi)封(feng)(feng)材(cai)料(liao)與液(ye)壓油(you)的相容性(xing)。還有(you)，各種不(bu)同(tong)(tong)(tong)(tong)的密(mi)(mi)封(feng)(feng)材(cai)料(liao)對(dui)你不(bu)同(tong)(tong)(tong)(tong)的工作(zuo)條(tiao)件表(biao)現(xian)出(chu)不(bu)同(tong)(tong)(tong)(tong)的性(xing)能(neng)。有(you)些(xie)耐(nai)(nai)熱(re)，有(you)些(xie)不(bu)耐(nai)(nai)熱(re);有(you)些(xie)耐(nai)(nai)酸，有(you)些(xie)耐(nai)(nai)堿，有(you)些(xie)耐(nai)(nai)水(shui)，有(you)些(xie)耐(nai)(nai)油(you);有(you)些(xie)抗熱(re)，有(you)些(xie)耐(nai)(nai)低溫(wen)，有(you)些(xie)耐(nai)(nai)高溫(wen)，等等。這(zhe)些(xie)因(yin)素在(zai)(zai)考(kao)慮密(mi)(mi)封(feng)(feng)件材(cai)料(liao)的時候需(xu)注意。