填(tian)(tian)料(liao)(liao)(liao)改集(ji)式(shi)密(mi)(mi)封(feng)(feng)是(shi)指通過預(yu)(yu)(yu)緊(jin)或(huo)介質壓力(li)的自緊(jin)作用(yong)(yong)(yong)使填(tian)(tian)料(liao)(liao)(liao)與轉動(dong)(dong)件(jian)及固定件(jian)之間(jian)產生壓緊(jin)力(li)的動(dong)(dong)密(mi)(mi)封(feng)(feng)裝置。又稱“填(tian)(tian)料(liao)(liao)(liao)函密(mi)(mi)封(feng)(feng)”。結(jie)構形式(shi)較多(duo)，主要(yao)由(you)填(tian)(tian)料(liao)(liao)(liao)、填(tian)(tian)料(liao)(liao)(liao)箱和(he)填(tian)(tian)料(liao)(liao)(liao)固定件(jian)組成(cheng)。常用(yong)(yong)(yong)的填(tian)(tian)料(liao)(liao)(liao)材(cai)料(liao)(liao)(liao)有石(shi)棉(mian)織(zhi)物、碳(tan)纖維、橡膠、柔性(xing)石(shi)墨和(he)工程塑料(liao)(liao)(liao)等，預(yu)(yu)(yu)制成(cheng)環(huan)狀或(huo)條狀（有的需預(yu)(yu)(yu)先浸漬潤滑性(xing)好的填(tian)(tian)充物），并采(cai)用(yong)(yong)(yong)多(duo)環(huan)或(huo)螺旋狀多(duo)層(ceng)結(jie)構。填(tian)(tian)料(liao)(liao)(liao)箱用(yong)(yong)(yong)以安置填(tian)(tian)料(liao)(liao)(liao)。填(tian)(tian)料(liao)(liao)(liao)固定件(jian)包(bao)括壓蓋、螺栓(shuan)和(he)彈簧等，用(yong)(yong)(yong)以使填(tian)(tian)料(liao)(liao)(liao)預(yu)(yu)(yu)緊(jin)，工作時(shi)阻止(zhi)介質外漏，彈簧可起補償作用(yong)(yong)(yong)。

　　填(tian)(tian)料(liao)裝入填(tian)(tian)料(liao)腔以后，經壓(ya)蓋(gai)螺絲對(dui)它作(zuo)軸向(xiang)壓(ya)縮，當軸與(yu)(yu)(yu)填(tian)(tian)料(liao)有相對(dui)運動(dong)時，由(you)(you)于填(tian)(tian)料(liao)的(de)(de)(de)塑性，使(shi)它產生徑向(xiang)力，并與(yu)(yu)(yu)軸緊密(mi)接(jie)(jie)(jie)(jie)觸。與(yu)(yu)(yu)此(ci)同時，填(tian)(tian)料(liao)中浸漬(zi)的(de)(de)(de)潤(run)滑(hua)劑被擠出，在(zai)接(jie)(jie)(jie)(jie)觸面之(zhi)(zhi)間形(xing)成油(you)膜。由(you)(you)于接(jie)(jie)(jie)(jie)觸狀態(tai)并不是(shi)特別均勻的(de)(de)(de)，接(jie)(jie)(jie)(jie)觸部位(wei)(wei)便(bian)出現(xian)“邊界潤(run)滑(hua)”狀態(tai)，稱為“軸承(cheng)效應”；而未(wei)接(jie)(jie)(jie)(jie)觸的(de)(de)(de)凹部形(xing)成小油(you)槽，有較厚的(de)(de)(de)油(you)膜，接(jie)(jie)(jie)(jie)觸部位(wei)(wei)與(yu)(yu)(yu)非接(jie)(jie)(jie)(jie)觸部位(wei)(wei)組成一道(dao)不規(gui)則的(de)(de)(de)迷宮(gong)(gong)，起(qi)阻止液流泄漏(lou)的(de)(de)(de)作(zuo)用，此(ci)稱“迷宮(gong)(gong)效應”。這就是(shi)填(tian)(tian)料(liao)密(mi)封(feng)的(de)(de)(de)機(ji)理(li)。顯然，良好的(de)(de)(de)密(mi)封(feng)在(zai)于維持“軸承(cheng)效應”和“迷宮(gong)(gong)效應”。也就是(shi)說，要保持良好的(de)(de)(de)潤(run)滑(hua)和適當的(de)(de)(de)壓(ya)緊。若潤(run)滑(hua)不良，或壓(ya)得過緊都會使(shi)油(you)膜中斷(duan)，造成填(tian)(tian)料(liao)與(yu)(yu)(yu)軸之(zhi)(zhi)間出現(xian)干摩擦，最后導致燒(shao)軸和出現(xian)嚴重磨損。

　　為(wei)(wei)此(ci)，需要(yao)經常對填(tian)(tian)(tian)料(liao)的壓(ya)緊(jin)程度(du)進行調整(zheng)，以便填(tian)(tian)(tian)料(liao)中的潤(run)滑(hua)劑在(zai)運行一段(duan)時(shi)間流失之后，再擠(ji)出一些(xie)潤(run)滑(hua)劑，同時(shi)補償填(tian)(tian)(tian)料(liao)因體積變化所造成(cheng)的壓(ya)緊(jin)力(li)松弛。顯(xian)然，這(zhe)樣經常擠(ji)壓(ya)填(tian)(tian)(tian)料(liao)，最終(zhong)將(jiang)使(shi)浸漬劑枯(ku)竭，所以定期更換填(tian)(tian)(tian)料(liao)是必要(yao)的。此(ci)外，為(wei)(wei)了維持液(ye)膜(mo)和帶走摩(mo)擦(ca)熱，有(you)(you)意讓填(tian)(tian)(tian)料(liao)處(chu)有(you)(you)少量(liang)泄(xie)漏也是必要(yao)的。