1、液壓密封件之形(xing)式(shi)選擇

　　在液壓系統(tong)中，常(chang)見(jian)的(de)密(mi)封形(xing)式有(you)擠(ji)壓型(xing)O形(xing)密(mi)封圈(quan)、Y形(xing)圈(quan)、V形(xing)圈(quan)、U形(xing)圈(quan)唇形(xing)密(mi)封。唇形(xing)密(mi)封圈(quan)主要用(yong)于往復(fu)動(dong)密(mi)封，與O形(xing)圈(quan)等擠(ji)壓密(mi)封相比，往復(fu)動(dong)密(mi)封使用(yong)唇形(xing)密(mi)封圈(quan)具有(you)更好的(de)綜合性(xing)能和(he)更長(chang)的(de)使用(yong)壽命(ming)。

　　唇(chun)(chun)形(xing)(xing)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)圈的(de)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)壓(ya)緊力(li)(li)是隨(sui)介質壓(ya)力(li)(li)的(de)改變(bian)(bian)而(er)(er)變(bian)(bian)化的(de)，工作中(zhong)(zhong)始終應監(jian)控(kong)介質壓(ya)力(li)(li)的(de)變(bian)(bian)化，即能保證足(zu)夠的(de)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)壓(ya)緊力(li)(li)，又不至于產(chan)生(sheng)過大的(de)摩擦(ca)力(li)(li)，擠壓(ya)性密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)主要靠預(yu)壓(ya)緊力(li)(li)產(chan)生(sheng)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)力(li)(li)，密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)圈接觸(chu)壓(ya)力(li)(li)預(yu)先給定，工作中(zhong)(zhong)不能根(gen)據介質壓(ya)力(li)(li)的(de)改變(bian)(bian)而(er)(er)變(bian)(bian)化。大的(de)預(yu)壓(ya)力(li)(li)會使密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)圈與密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)面接觸(chu)面積增大，產(chan)生(sheng)很大的(de)摩擦(ca)阻力(li)(li)，過大的(de)摩擦(ca)力(li)(li)會造成密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)圈的(de)破(po)損(sun)，在低壓(ya)時造成啟動困難，或產(chan)生(sheng)爬行(xing)現象，唇(chun)(chun)形(xing)(xing)密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)圈可(ke)以(yi)通過唇(chun)(chun)部撐開，變(bian)(bian)形(xing)(xing)補償小的(de)磨損(sun)量，保證密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)效果和密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)壽命;而(er)(er)O形(xing)(xing)圈隨(sui)著(zhu)摩擦(ca)余量的(de)減少，直接影響其密(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)性。

　　2、液壓密(mi)封件之材料(liao)選擇

　　密封(feng)(feng)件(jian)形式和結構現(xian)在一(yi)般已(yi)經(jing)定型，各(ge)密封(feng)(feng)件(jian)質(zhi)量區別主要在于制(zhi)作材(cai)(cai)料上。密封(feng)(feng)材(cai)(cai)料主要使用(yong)(yong)橡膠(jiao)和合(he)成樹脂(zhi)。由于各(ge)種材(cai)(cai)料性(xing)能(neng)特點(dian)不(bu)(bu)同(tong)，性(xing)能(neng)特點(dian)不(bu)(bu)同(tong)，用(yong)(yong)途也就(jiu)有(you)(you)(you)(you)(you)(you)所不(bu)(bu)同(tong)。選用(yong)(yong)時需根據不(bu)(bu)同(tong)的(de)使用(yong)(yong)條(tiao)(tiao)件(jian)和不(bu)(bu)同(tong)的(de)使用(yong)(yong)條(tiao)(tiao)件(jian)作出合(he)適的(de)選擇。另外，某一(yi)材(cai)(cai)質(zhi)的(de)密封(feng)(feng)對被密封(feng)(feng)的(de)某一(yi)工作介(jie)質(zhi)(如礦物油(you)等(deng)(deng))表(biao)現(xian)較(jiao)好的(de)密封(feng)(feng)性(xing)能(neng)，而對另一(yi)介(jie)質(zhi)表(biao)現(xian)極差，這(zhe)就(jiu)是密封(feng)(feng)材(cai)(cai)料與(yu)液壓油(you)的(de)相容(rong)性(xing)。還有(you)(you)(you)(you)(you)(you)，各(ge)種不(bu)(bu)同(tong)的(de)密封(feng)(feng)材(cai)(cai)料對你不(bu)(bu)同(tong)的(de)工作條(tiao)(tiao)件(jian)表(biao)現(xian)出不(bu)(bu)同(tong)的(de)性(xing)能(neng)。有(you)(you)(you)(you)(you)(you)些(xie)耐(nai)熱(re)，有(you)(you)(you)(you)(you)(you)些(xie)不(bu)(bu)耐(nai)熱(re);有(you)(you)(you)(you)(you)(you)些(xie)耐(nai)酸，有(you)(you)(you)(you)(you)(you)些(xie)耐(nai)堿，有(you)(you)(you)(you)(you)(you)些(xie)耐(nai)水(shui)，有(you)(you)(you)(you)(you)(you)些(xie)耐(nai)油(you);有(you)(you)(you)(you)(you)(you)些(xie)抗熱(re)，有(you)(you)(you)(you)(you)(you)些(xie)耐(nai)低溫(wen)，有(you)(you)(you)(you)(you)(you)些(xie)耐(nai)高溫(wen)，等(deng)(deng)等(deng)(deng)。這(zhe)些(xie)因素在考慮密封(feng)(feng)件(jian)材(cai)(cai)料的(de)時候需注意。