1、液壓密封件之(zhi)形式選(xuan)擇

　　在液壓(ya)系統中，常見的(de)(de)密(mi)(mi)(mi)封形(xing)式有(you)擠(ji)壓(ya)型O形(xing)密(mi)(mi)(mi)封圈(quan)(quan)、Y形(xing)圈(quan)(quan)、V形(xing)圈(quan)(quan)、U形(xing)圈(quan)(quan)唇形(xing)密(mi)(mi)(mi)封。唇形(xing)密(mi)(mi)(mi)封圈(quan)(quan)主要(yao)用(yong)于往復動(dong)密(mi)(mi)(mi)封，與O形(xing)圈(quan)(quan)等擠(ji)壓(ya)密(mi)(mi)(mi)封相比(bi)，往復動(dong)密(mi)(mi)(mi)封使(shi)用(yong)唇形(xing)密(mi)(mi)(mi)封圈(quan)(quan)具有(you)更好(hao)的(de)(de)綜合性能和更長的(de)(de)使(shi)用(yong)壽命。

　　唇形密(mi)(mi)封(feng)(feng)(feng)(feng)(feng)圈(quan)的(de)(de)(de)(de)密(mi)(mi)封(feng)(feng)(feng)(feng)(feng)壓(ya)(ya)(ya)(ya)緊力(li)(li)是(shi)隨(sui)介質(zhi)壓(ya)(ya)(ya)(ya)力(li)(li)的(de)(de)(de)(de)改變(bian)而變(bian)化的(de)(de)(de)(de)，工作(zuo)中始終應(ying)監控介質(zhi)壓(ya)(ya)(ya)(ya)力(li)(li)的(de)(de)(de)(de)變(bian)化，即(ji)能保證(zheng)(zheng)足夠的(de)(de)(de)(de)密(mi)(mi)封(feng)(feng)(feng)(feng)(feng)壓(ya)(ya)(ya)(ya)緊力(li)(li)，又不(bu)至于(yu)產生(sheng)(sheng)(sheng)過大(da)的(de)(de)(de)(de)摩擦(ca)力(li)(li)，擠壓(ya)(ya)(ya)(ya)性(xing)密(mi)(mi)封(feng)(feng)(feng)(feng)(feng)主要靠預(yu)壓(ya)(ya)(ya)(ya)緊力(li)(li)產生(sheng)(sheng)(sheng)密(mi)(mi)封(feng)(feng)(feng)(feng)(feng)力(li)(li)，密(mi)(mi)封(feng)(feng)(feng)(feng)(feng)圈(quan)接(jie)觸壓(ya)(ya)(ya)(ya)力(li)(li)預(yu)先給定，工作(zuo)中不(bu)能根據介質(zhi)壓(ya)(ya)(ya)(ya)力(li)(li)的(de)(de)(de)(de)改變(bian)而變(bian)化。大(da)的(de)(de)(de)(de)預(yu)壓(ya)(ya)(ya)(ya)力(li)(li)會使密(mi)(mi)封(feng)(feng)(feng)(feng)(feng)圈(quan)與密(mi)(mi)封(feng)(feng)(feng)(feng)(feng)面接(jie)觸面積(ji)增(zeng)大(da)，產生(sheng)(sheng)(sheng)很大(da)的(de)(de)(de)(de)摩擦(ca)阻力(li)(li)，過大(da)的(de)(de)(de)(de)摩擦(ca)力(li)(li)會造(zao)成(cheng)(cheng)密(mi)(mi)封(feng)(feng)(feng)(feng)(feng)圈(quan)的(de)(de)(de)(de)破損，在低壓(ya)(ya)(ya)(ya)時(shi)造(zao)成(cheng)(cheng)啟動困難，或產生(sheng)(sheng)(sheng)爬行現象，唇形密(mi)(mi)封(feng)(feng)(feng)(feng)(feng)圈(quan)可以通過唇部撐(cheng)開(kai)，變(bian)形補償小的(de)(de)(de)(de)磨損量，保證(zheng)(zheng)密(mi)(mi)封(feng)(feng)(feng)(feng)(feng)效果和密(mi)(mi)封(feng)(feng)(feng)(feng)(feng)壽命;而O形圈(quan)隨(sui)著摩擦(ca)余量的(de)(de)(de)(de)減少(shao)，直接(jie)影響其(qi)密(mi)(mi)封(feng)(feng)(feng)(feng)(feng)性(xing)。

　　2、液壓密封件(jian)之材料選擇

　　密(mi)(mi)(mi)封(feng)(feng)件形式和結構現在一(yi)般已經定(ding)型，各(ge)(ge)密(mi)(mi)(mi)封(feng)(feng)件質(zhi)(zhi)量區別主(zhu)要在于(yu)制作(zuo)材料(liao)上(shang)。密(mi)(mi)(mi)封(feng)(feng)材料(liao)主(zhu)要使用橡膠(jiao)和合(he)成樹(shu)脂。由于(yu)各(ge)(ge)種材料(liao)性能特(te)點不(bu)同(tong)(tong)，性能特(te)點不(bu)同(tong)(tong)，用途(tu)也就(jiu)有(you)所不(bu)同(tong)(tong)。選用時(shi)需(xu)根據不(bu)同(tong)(tong)的使用條件和不(bu)同(tong)(tong)的使用條件作(zuo)出合(he)適的選擇。另外，某(mou)一(yi)材質(zhi)(zhi)的密(mi)(mi)(mi)封(feng)(feng)對(dui)被(bei)密(mi)(mi)(mi)封(feng)(feng)的某(mou)一(yi)工(gong)作(zuo)介(jie)質(zhi)(zhi)(如礦物油(you)等(deng))表現較好的密(mi)(mi)(mi)封(feng)(feng)性能，而對(dui)另一(yi)介(jie)質(zhi)(zhi)表現極差(cha)，這就(jiu)是密(mi)(mi)(mi)封(feng)(feng)材料(liao)與液壓(ya)油(you)的相(xiang)容性。還有(you)，各(ge)(ge)種不(bu)同(tong)(tong)的密(mi)(mi)(mi)封(feng)(feng)材料(liao)對(dui)你不(bu)同(tong)(tong)的工(gong)作(zuo)條件表現出不(bu)同(tong)(tong)的性能。有(you)些(xie)耐熱(re)，有(you)些(xie)不(bu)耐熱(re);有(you)些(xie)耐酸，有(you)些(xie)耐堿，有(you)些(xie)耐水，有(you)些(xie)耐油(you);有(you)些(xie)抗熱(re)，有(you)些(xie)耐低溫(wen)，有(you)些(xie)耐高溫(wen)，等(deng)等(deng)。這些(xie)因素(su)在考慮密(mi)(mi)(mi)封(feng)(feng)件材料(liao)的時(shi)候需(xu)注意(yi)。