1、液壓(ya)密封件(jian)之形式(shi)選擇

　　在液(ye)壓系統中，常見的(de)密(mi)封(feng)(feng)形(xing)(xing)式有(you)(you)擠(ji)壓型O形(xing)(xing)密(mi)封(feng)(feng)圈(quan)(quan)、Y形(xing)(xing)圈(quan)(quan)、V形(xing)(xing)圈(quan)(quan)、U形(xing)(xing)圈(quan)(quan)唇(chun)(chun)形(xing)(xing)密(mi)封(feng)(feng)。唇(chun)(chun)形(xing)(xing)密(mi)封(feng)(feng)圈(quan)(quan)主要(yao)用于往(wang)復(fu)動密(mi)封(feng)(feng)，與O形(xing)(xing)圈(quan)(quan)等擠(ji)壓密(mi)封(feng)(feng)相比(bi)，往(wang)復(fu)動密(mi)封(feng)(feng)使用唇(chun)(chun)形(xing)(xing)密(mi)封(feng)(feng)圈(quan)(quan)具(ju)有(you)(you)更好的(de)綜合性(xing)能和更長的(de)使用壽命(ming)。

　　唇形(xing)密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)圈(quan)(quan)的(de)(de)密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)壓(ya)緊(jin)力(li)(li)是隨介質壓(ya)力(li)(li)的(de)(de)改變(bian)(bian)而變(bian)(bian)化的(de)(de)，工作中(zhong)始終應(ying)監控(kong)介質壓(ya)力(li)(li)的(de)(de)變(bian)(bian)化，即能保證足(zu)夠的(de)(de)密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)壓(ya)緊(jin)力(li)(li)，又不(bu)至于(yu)產(chan)(chan)生過大(da)的(de)(de)摩擦(ca)力(li)(li)，擠(ji)壓(ya)性密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)主要靠預壓(ya)緊(jin)力(li)(li)產(chan)(chan)生密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)力(li)(li)，密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)圈(quan)(quan)接(jie)觸壓(ya)力(li)(li)預先給定，工作中(zhong)不(bu)能根據介質壓(ya)力(li)(li)的(de)(de)改變(bian)(bian)而變(bian)(bian)化。大(da)的(de)(de)預壓(ya)力(li)(li)會使密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)圈(quan)(quan)與密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)面(mian)接(jie)觸面(mian)積增大(da)，產(chan)(chan)生很大(da)的(de)(de)摩擦(ca)阻力(li)(li)，過大(da)的(de)(de)摩擦(ca)力(li)(li)會造成密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)圈(quan)(quan)的(de)(de)破損，在(zai)低壓(ya)時造成啟動困難，或(huo)產(chan)(chan)生爬行現象，唇形(xing)密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)圈(quan)(quan)可(ke)以通過唇部撐開，變(bian)(bian)形(xing)補(bu)償小(xiao)的(de)(de)磨損量(liang)，保證密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)效果和(he)密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)壽(shou)命;而O形(xing)圈(quan)(quan)隨著摩擦(ca)余量(liang)的(de)(de)減少，直(zhi)接(jie)影響其(qi)密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)性。

　　2、液壓密(mi)封(feng)件之材(cai)料選擇

　　密(mi)封(feng)(feng)(feng)(feng)件(jian)形式和(he)結構(gou)現(xian)在一(yi)般已經定(ding)型，各(ge)密(mi)封(feng)(feng)(feng)(feng)件(jian)質(zhi)量區別(bie)主要(yao)在于(yu)制作(zuo)材(cai)(cai)(cai)(cai)料(liao)上。密(mi)封(feng)(feng)(feng)(feng)材(cai)(cai)(cai)(cai)料(liao)主要(yao)使(shi)用(yong)(yong)橡膠和(he)合成樹脂。由于(yu)各(ge)種材(cai)(cai)(cai)(cai)料(liao)性能(neng)(neng)特點(dian)不(bu)(bu)(bu)(bu)同(tong)(tong)(tong)，性能(neng)(neng)特點(dian)不(bu)(bu)(bu)(bu)同(tong)(tong)(tong)，用(yong)(yong)途也(ye)就有(you)(you)所不(bu)(bu)(bu)(bu)同(tong)(tong)(tong)。選用(yong)(yong)時需(xu)根據不(bu)(bu)(bu)(bu)同(tong)(tong)(tong)的(de)(de)使(shi)用(yong)(yong)條件(jian)和(he)不(bu)(bu)(bu)(bu)同(tong)(tong)(tong)的(de)(de)使(shi)用(yong)(yong)條件(jian)作(zuo)出合適的(de)(de)選擇(ze)。另外，某一(yi)材(cai)(cai)(cai)(cai)質(zhi)的(de)(de)密(mi)封(feng)(feng)(feng)(feng)對(dui)被密(mi)封(feng)(feng)(feng)(feng)的(de)(de)某一(yi)工(gong)作(zuo)介質(zhi)(如礦物油等)表(biao)現(xian)較好的(de)(de)密(mi)封(feng)(feng)(feng)(feng)性能(neng)(neng)，而對(dui)另一(yi)介質(zhi)表(biao)現(xian)極差，這就是密(mi)封(feng)(feng)(feng)(feng)材(cai)(cai)(cai)(cai)料(liao)與液壓油的(de)(de)相容性。還有(you)(you)，各(ge)種不(bu)(bu)(bu)(bu)同(tong)(tong)(tong)的(de)(de)密(mi)封(feng)(feng)(feng)(feng)材(cai)(cai)(cai)(cai)料(liao)對(dui)你不(bu)(bu)(bu)(bu)同(tong)(tong)(tong)的(de)(de)工(gong)作(zuo)條件(jian)表(biao)現(xian)出不(bu)(bu)(bu)(bu)同(tong)(tong)(tong)的(de)(de)性能(neng)(neng)。有(you)(you)些(xie)(xie)(xie)(xie)耐(nai)(nai)熱，有(you)(you)些(xie)(xie)(xie)(xie)不(bu)(bu)(bu)(bu)耐(nai)(nai)熱;有(you)(you)些(xie)(xie)(xie)(xie)耐(nai)(nai)酸(suan)，有(you)(you)些(xie)(xie)(xie)(xie)耐(nai)(nai)堿，有(you)(you)些(xie)(xie)(xie)(xie)耐(nai)(nai)水，有(you)(you)些(xie)(xie)(xie)(xie)耐(nai)(nai)油;有(you)(you)些(xie)(xie)(xie)(xie)抗(kang)熱，有(you)(you)些(xie)(xie)(xie)(xie)耐(nai)(nai)低溫，有(you)(you)些(xie)(xie)(xie)(xie)耐(nai)(nai)高溫，等等。這些(xie)(xie)(xie)(xie)因素在考慮密(mi)封(feng)(feng)(feng)(feng)件(jian)材(cai)(cai)(cai)(cai)料(liao)的(de)(de)時候需(xu)注意。