1、液(ye)壓密封件之形式選擇

　　在液(ye)壓(ya)系統(tong)中(zhong)，常見(jian)的密(mi)封(feng)形(xing)(xing)式有擠壓(ya)型O形(xing)(xing)密(mi)封(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)。唇(chun)(chun)形(xing)(xing)密(mi)封(feng)圈(quan)(quan)主要用(yong)于往(wang)復(fu)動密(mi)封(feng)，與O形(xing)(xing)圈(quan)(quan)等擠壓(ya)密(mi)封(feng)相比，往(wang)復(fu)動密(mi)封(feng)使用(yong)唇(chun)(chun)形(xing)(xing)密(mi)封(feng)圈(quan)(quan)具有更好的綜合性(xing)能和更長的使用(yong)壽命(ming)。

　　唇(chun)形(xing)密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)圈(quan)的密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)壓(ya)(ya)(ya)(ya)(ya)緊(jin)力(li)(li)(li)是隨介(jie)質(zhi)壓(ya)(ya)(ya)(ya)(ya)力(li)(li)(li)的改變(bian)而變(bian)化(hua)的，工作(zuo)中(zhong)始終應(ying)監(jian)控(kong)介(jie)質(zhi)壓(ya)(ya)(ya)(ya)(ya)力(li)(li)(li)的變(bian)化(hua)，即能保證足夠的密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)壓(ya)(ya)(ya)(ya)(ya)緊(jin)力(li)(li)(li)，又不至于產(chan)生(sheng)過大(da)(da)的摩擦力(li)(li)(li)，擠壓(ya)(ya)(ya)(ya)(ya)性密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)主要靠預壓(ya)(ya)(ya)(ya)(ya)緊(jin)力(li)(li)(li)產(chan)生(sheng)密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)力(li)(li)(li)，密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)圈(quan)接(jie)觸壓(ya)(ya)(ya)(ya)(ya)力(li)(li)(li)預先給定(ding)，工作(zuo)中(zhong)不能根據介(jie)質(zhi)壓(ya)(ya)(ya)(ya)(ya)力(li)(li)(li)的改變(bian)而變(bian)化(hua)。大(da)(da)的預壓(ya)(ya)(ya)(ya)(ya)力(li)(li)(li)會使密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)圈(quan)與(yu)密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)面(mian)接(jie)觸面(mian)積增大(da)(da)，產(chan)生(sheng)很大(da)(da)的摩擦阻(zu)力(li)(li)(li)，過大(da)(da)的摩擦力(li)(li)(li)會造成(cheng)密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)圈(quan)的破損，在低(di)壓(ya)(ya)(ya)(ya)(ya)時造成(cheng)啟動困難，或產(chan)生(sheng)爬行現象，唇(chun)形(xing)密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)圈(quan)可以通過唇(chun)部撐(cheng)開，變(bian)形(xing)補償小的磨損量(liang)，保證密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)效(xiao)果和密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)壽(shou)命;而O形(xing)圈(quan)隨著摩擦余量(liang)的減少，直接(jie)影響其密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)性。

　　2、液壓密(mi)封件(jian)之(zhi)材料選擇

　　密(mi)(mi)封(feng)(feng)件(jian)(jian)形式和(he)結構現(xian)在(zai)(zai)一(yi)般已(yi)經定型，各(ge)(ge)密(mi)(mi)封(feng)(feng)件(jian)(jian)質量區別主(zhu)要(yao)在(zai)(zai)于制(zhi)作(zuo)材(cai)(cai)料(liao)上。密(mi)(mi)封(feng)(feng)材(cai)(cai)料(liao)主(zhu)要(yao)使(shi)用(yong)(yong)(yong)橡膠和(he)合成樹脂(zhi)。由于各(ge)(ge)種(zhong)(zhong)材(cai)(cai)料(liao)性(xing)(xing)(xing)(xing)能特(te)點不(bu)同，性(xing)(xing)(xing)(xing)能特(te)點不(bu)同，用(yong)(yong)(yong)途也就(jiu)有(you)(you)(you)所(suo)不(bu)同。選用(yong)(yong)(yong)時需根據不(bu)同的(de)(de)使(shi)用(yong)(yong)(yong)條件(jian)(jian)和(he)不(bu)同的(de)(de)使(shi)用(yong)(yong)(yong)條件(jian)(jian)作(zuo)出合適的(de)(de)選擇。另(ling)外，某一(yi)材(cai)(cai)質的(de)(de)密(mi)(mi)封(feng)(feng)對(dui)被密(mi)(mi)封(feng)(feng)的(de)(de)某一(yi)工作(zuo)介(jie)質(如礦物油等)表現(xian)較好的(de)(de)密(mi)(mi)封(feng)(feng)性(xing)(xing)(xing)(xing)能，而對(dui)另(ling)一(yi)介(jie)質表現(xian)極差，這(zhe)就(jiu)是密(mi)(mi)封(feng)(feng)材(cai)(cai)料(liao)與液(ye)壓油的(de)(de)相容性(xing)(xing)(xing)(xing)。還有(you)(you)(you)，各(ge)(ge)種(zhong)(zhong)不(bu)同的(de)(de)密(mi)(mi)封(feng)(feng)材(cai)(cai)料(liao)對(dui)你不(bu)同的(de)(de)工作(zuo)條件(jian)(jian)表現(xian)出不(bu)同的(de)(de)性(xing)(xing)(xing)(xing)能。有(you)(you)(you)些(xie)(xie)(xie)耐(nai)(nai)(nai)熱，有(you)(you)(you)些(xie)(xie)(xie)不(bu)耐(nai)(nai)(nai)熱;有(you)(you)(you)些(xie)(xie)(xie)耐(nai)(nai)(nai)酸，有(you)(you)(you)些(xie)(xie)(xie)耐(nai)(nai)(nai)堿，有(you)(you)(you)些(xie)(xie)(xie)耐(nai)(nai)(nai)水(shui)，有(you)(you)(you)些(xie)(xie)(xie)耐(nai)(nai)(nai)油;有(you)(you)(you)些(xie)(xie)(xie)抗熱，有(you)(you)(you)些(xie)(xie)(xie)耐(nai)(nai)(nai)低溫，有(you)(you)(you)些(xie)(xie)(xie)耐(nai)(nai)(nai)高溫，等等。這(zhe)些(xie)(xie)(xie)因素在(zai)(zai)考(kao)慮密(mi)(mi)封(feng)(feng)件(jian)(jian)材(cai)(cai)料(liao)的(de)(de)時候需注意。