1、液壓(ya)密(mi)封件之形式選擇

　　在液壓(ya)(ya)系統中，常見的(de)(de)密(mi)封形(xing)式有(you)擠壓(ya)(ya)型O形(xing)密(mi)封圈(quan)、Y形(xing)圈(quan)、V形(xing)圈(quan)、U形(xing)圈(quan)唇(chun)形(xing)密(mi)封。唇(chun)形(xing)密(mi)封圈(quan)主要用于往復動(dong)密(mi)封，與O形(xing)圈(quan)等擠壓(ya)(ya)密(mi)封相(xiang)比，往復動(dong)密(mi)封使用唇(chun)形(xing)密(mi)封圈(quan)具有(you)更好的(de)(de)綜(zong)合性能和更長的(de)(de)使用壽命(ming)。

　　唇形(xing)(xing)密(mi)(mi)(mi)(mi)封(feng)圈的密(mi)(mi)(mi)(mi)封(feng)壓(ya)(ya)緊力(li)是隨介質(zhi)壓(ya)(ya)力(li)的改變(bian)而(er)變(bian)化的，工(gong)作中始終(zhong)應監控介質(zhi)壓(ya)(ya)力(li)的變(bian)化，即能保(bao)證足夠的密(mi)(mi)(mi)(mi)封(feng)壓(ya)(ya)緊力(li)，又不(bu)至于產生過(guo)大的摩擦(ca)(ca)力(li)，擠(ji)壓(ya)(ya)性(xing)密(mi)(mi)(mi)(mi)封(feng)主要靠(kao)預(yu)壓(ya)(ya)緊力(li)產生密(mi)(mi)(mi)(mi)封(feng)力(li)，密(mi)(mi)(mi)(mi)封(feng)圈接觸壓(ya)(ya)力(li)預(yu)先給定，工(gong)作中不(bu)能根據介質(zhi)壓(ya)(ya)力(li)的改變(bian)而(er)變(bian)化。大的預(yu)壓(ya)(ya)力(li)會(hui)使(shi)密(mi)(mi)(mi)(mi)封(feng)圈與密(mi)(mi)(mi)(mi)封(feng)面(mian)(mian)接觸面(mian)(mian)積增大，產生很大的摩擦(ca)(ca)阻(zu)力(li)，過(guo)大的摩擦(ca)(ca)力(li)會(hui)造成密(mi)(mi)(mi)(mi)封(feng)圈的破損，在低壓(ya)(ya)時造成啟動(dong)困難(nan)，或產生爬行現(xian)象，唇形(xing)(xing)密(mi)(mi)(mi)(mi)封(feng)圈可以通過(guo)唇部撐(cheng)開，變(bian)形(xing)(xing)補(bu)償小的磨損量(liang)，保(bao)證密(mi)(mi)(mi)(mi)封(feng)效(xiao)果和密(mi)(mi)(mi)(mi)封(feng)壽命;而(er)O形(xing)(xing)圈隨著(zhu)摩擦(ca)(ca)余(yu)量(liang)的減少，直接影(ying)響其密(mi)(mi)(mi)(mi)封(feng)性(xing)。

　　2、液壓密封(feng)件之(zhi)材料(liao)選擇

　　密封(feng)件(jian)形(xing)式和結構(gou)現(xian)在(zai)一般已(yi)經(jing)定型，各(ge)密封(feng)件(jian)質(zhi)(zhi)量區(qu)別(bie)主要(yao)在(zai)于(yu)制(zhi)作材(cai)(cai)料(liao)(liao)上(shang)。密封(feng)材(cai)(cai)料(liao)(liao)主要(yao)使用(yong)橡膠和合成樹脂。由于(yu)各(ge)種(zhong)材(cai)(cai)料(liao)(liao)性能(neng)特點(dian)不(bu)(bu)(bu)(bu)同(tong)(tong)，性能(neng)特點(dian)不(bu)(bu)(bu)(bu)同(tong)(tong)，用(yong)途也就有(you)(you)所不(bu)(bu)(bu)(bu)同(tong)(tong)。選用(yong)時需根據(ju)不(bu)(bu)(bu)(bu)同(tong)(tong)的(de)(de)(de)(de)(de)使用(yong)條(tiao)件(jian)和不(bu)(bu)(bu)(bu)同(tong)(tong)的(de)(de)(de)(de)(de)使用(yong)條(tiao)件(jian)作出合適的(de)(de)(de)(de)(de)選擇。另外(wai)，某一材(cai)(cai)質(zhi)(zhi)的(de)(de)(de)(de)(de)密封(feng)對被密封(feng)的(de)(de)(de)(de)(de)某一工(gong)作介質(zhi)(zhi)(如(ru)礦物(wu)油等(deng))表(biao)現(xian)較好的(de)(de)(de)(de)(de)密封(feng)性能(neng)，而對另一介質(zhi)(zhi)表(biao)現(xian)極差，這(zhe)就是密封(feng)材(cai)(cai)料(liao)(liao)與液壓油的(de)(de)(de)(de)(de)相容性。還有(you)(you)，各(ge)種(zhong)不(bu)(bu)(bu)(bu)同(tong)(tong)的(de)(de)(de)(de)(de)密封(feng)材(cai)(cai)料(liao)(liao)對你不(bu)(bu)(bu)(bu)同(tong)(tong)的(de)(de)(de)(de)(de)工(gong)作條(tiao)件(jian)表(biao)現(xian)出不(bu)(bu)(bu)(bu)同(tong)(tong)的(de)(de)(de)(de)(de)性能(neng)。有(you)(you)些(xie)(xie)(xie)耐(nai)(nai)(nai)熱，有(you)(you)些(xie)(xie)(xie)不(bu)(bu)(bu)(bu)耐(nai)(nai)(nai)熱;有(you)(you)些(xie)(xie)(xie)耐(nai)(nai)(nai)酸，有(you)(you)些(xie)(xie)(xie)耐(nai)(nai)(nai)堿，有(you)(you)些(xie)(xie)(xie)耐(nai)(nai)(nai)水(shui)，有(you)(you)些(xie)(xie)(xie)耐(nai)(nai)(nai)油;有(you)(you)些(xie)(xie)(xie)抗熱，有(you)(you)些(xie)(xie)(xie)耐(nai)(nai)(nai)低溫，有(you)(you)些(xie)(xie)(xie)耐(nai)(nai)(nai)高溫，等(deng)等(deng)。這(zhe)些(xie)(xie)(xie)因(yin)素在(zai)考慮密封(feng)件(jian)材(cai)(cai)料(liao)(liao)的(de)(de)(de)(de)(de)時候需注意。