1、液壓(ya)密封件之形式選(xuan)擇

　　在液壓(ya)系(xi)統中，常(chang)見的密(mi)(mi)封形(xing)(xing)(xing)式有擠壓(ya)型O形(xing)(xing)(xing)密(mi)(mi)封圈(quan)(quan)(quan)、Y形(xing)(xing)(xing)圈(quan)(quan)(quan)、V形(xing)(xing)(xing)圈(quan)(quan)(quan)、U形(xing)(xing)(xing)圈(quan)(quan)(quan)唇形(xing)(xing)(xing)密(mi)(mi)封。唇形(xing)(xing)(xing)密(mi)(mi)封圈(quan)(quan)(quan)主要(yao)用于往復(fu)動密(mi)(mi)封，與O形(xing)(xing)(xing)圈(quan)(quan)(quan)等擠壓(ya)密(mi)(mi)封相(xiang)比(bi)，往復(fu)動密(mi)(mi)封使(shi)用唇形(xing)(xing)(xing)密(mi)(mi)封圈(quan)(quan)(quan)具有更(geng)好的綜(zong)合性(xing)能和更(geng)長的使(shi)用壽(shou)命。

　　唇形(xing)密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)圈(quan)的(de)密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)壓(ya)緊(jin)力(li)(li)(li)(li)是隨介(jie)質(zhi)(zhi)壓(ya)力(li)(li)(li)(li)的(de)改(gai)變而變化的(de)，工作中(zhong)始(shi)終應監控介(jie)質(zhi)(zhi)壓(ya)力(li)(li)(li)(li)的(de)變化，即(ji)能(neng)保證足夠的(de)密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)壓(ya)緊(jin)力(li)(li)(li)(li)，又不(bu)至(zhi)于產(chan)生(sheng)過大(da)的(de)摩擦力(li)(li)(li)(li)，擠(ji)壓(ya)性(xing)密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)主要(yao)靠預壓(ya)緊(jin)力(li)(li)(li)(li)產(chan)生(sheng)密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)力(li)(li)(li)(li)，密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)圈(quan)接(jie)觸(chu)壓(ya)力(li)(li)(li)(li)預先給定，工作中(zhong)不(bu)能(neng)根據介(jie)質(zhi)(zhi)壓(ya)力(li)(li)(li)(li)的(de)改(gai)變而變化。大(da)的(de)預壓(ya)力(li)(li)(li)(li)會(hui)使密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)圈(quan)與密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)面接(jie)觸(chu)面積增大(da)，產(chan)生(sheng)很大(da)的(de)摩擦阻力(li)(li)(li)(li)，過大(da)的(de)摩擦力(li)(li)(li)(li)會(hui)造成密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)圈(quan)的(de)破損(sun)，在低壓(ya)時造成啟(qi)動(dong)困難，或產(chan)生(sheng)爬行現象，唇形(xing)密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)圈(quan)可以(yi)通過唇部撐開，變形(xing)補償(chang)小的(de)磨損(sun)量，保證密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)效果和密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)壽(shou)命;而O形(xing)圈(quan)隨著摩擦余量的(de)減少，直接(jie)影響(xiang)其密(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)性(xing)。

　　2、液壓密封件之材料選擇

　　密封(feng)(feng)件(jian)形式和結構現在一(yi)般已經定(ding)型，各(ge)密封(feng)(feng)件(jian)質(zhi)(zhi)量(liang)區別(bie)主要在于(yu)制作(zuo)(zuo)材(cai)(cai)料上。密封(feng)(feng)材(cai)(cai)料主要使(shi)(shi)用橡膠和合成(cheng)樹脂。由于(yu)各(ge)種材(cai)(cai)料性(xing)能(neng)特點(dian)(dian)不(bu)(bu)同，性(xing)能(neng)特點(dian)(dian)不(bu)(bu)同，用途也(ye)就(jiu)有(you)(you)(you)所不(bu)(bu)同。選(xuan)用時(shi)需根據不(bu)(bu)同的(de)(de)使(shi)(shi)用條件(jian)和不(bu)(bu)同的(de)(de)使(shi)(shi)用條件(jian)作(zuo)(zuo)出合適的(de)(de)選(xuan)擇。另外，某一(yi)材(cai)(cai)質(zhi)(zhi)的(de)(de)密封(feng)(feng)對被密封(feng)(feng)的(de)(de)某一(yi)工(gong)作(zuo)(zuo)介(jie)質(zhi)(zhi)(如(ru)礦物油(you)等(deng))表現較好的(de)(de)密封(feng)(feng)性(xing)能(neng)，而對另一(yi)介(jie)質(zhi)(zhi)表現極差，這就(jiu)是密封(feng)(feng)材(cai)(cai)料與液(ye)壓油(you)的(de)(de)相容(rong)性(xing)。還有(you)(you)(you)，各(ge)種不(bu)(bu)同的(de)(de)密封(feng)(feng)材(cai)(cai)料對你不(bu)(bu)同的(de)(de)工(gong)作(zuo)(zuo)條件(jian)表現出不(bu)(bu)同的(de)(de)性(xing)能(neng)。有(you)(you)(you)些(xie)耐(nai)(nai)(nai)熱，有(you)(you)(you)些(xie)不(bu)(bu)耐(nai)(nai)(nai)熱;有(you)(you)(you)些(xie)耐(nai)(nai)(nai)酸，有(you)(you)(you)些(xie)耐(nai)(nai)(nai)堿，有(you)(you)(you)些(xie)耐(nai)(nai)(nai)水，有(you)(you)(you)些(xie)耐(nai)(nai)(nai)油(you);有(you)(you)(you)些(xie)抗熱，有(you)(you)(you)些(xie)耐(nai)(nai)(nai)低溫(wen)，有(you)(you)(you)些(xie)耐(nai)(nai)(nai)高溫(wen)，等(deng)等(deng)。這些(xie)因素在考慮密封(feng)(feng)件(jian)材(cai)(cai)料的(de)(de)時(shi)候需注(zhu)意。