填(tian)(tian)(tian)料(liao)(liao)(liao)(liao)改(gai)集(ji)式密(mi)(mi)封(feng)是(shi)指(zhi)通過預緊或介質壓力的自緊作(zuo)用(yong)使填(tian)(tian)(tian)料(liao)(liao)(liao)(liao)與轉動(dong)件(jian)及固(gu)(gu)定(ding)件(jian)之間產生壓緊力的動(dong)密(mi)(mi)封(feng)裝置(zhi)。又(you)稱(cheng)“填(tian)(tian)(tian)料(liao)(liao)(liao)(liao)函密(mi)(mi)封(feng)”。結構形式較多，主(zhu)要(yao)由填(tian)(tian)(tian)料(liao)(liao)(liao)(liao)、填(tian)(tian)(tian)料(liao)(liao)(liao)(liao)箱(xiang)和填(tian)(tian)(tian)料(liao)(liao)(liao)(liao)固(gu)(gu)定(ding)件(jian)組成(cheng)。常用(yong)的填(tian)(tian)(tian)料(liao)(liao)(liao)(liao)材料(liao)(liao)(liao)(liao)有石棉織物、碳(tan)纖(xian)維(wei)、橡膠(jiao)、柔(rou)性(xing)石墨和工程塑料(liao)(liao)(liao)(liao)等，預制(zhi)成(cheng)環狀或條(tiao)狀（有的需(xu)預先浸漬潤滑性(xing)好的填(tian)(tian)(tian)充物），并采(cai)用(yong)多環或螺旋(xuan)狀多層結構。填(tian)(tian)(tian)料(liao)(liao)(liao)(liao)箱(xiang)用(yong)以安置(zhi)填(tian)(tian)(tian)料(liao)(liao)(liao)(liao)。填(tian)(tian)(tian)料(liao)(liao)(liao)(liao)固(gu)(gu)定(ding)件(jian)包括(kuo)壓蓋、螺栓和彈(dan)簧等，用(yong)以使填(tian)(tian)(tian)料(liao)(liao)(liao)(liao)預緊，工作(zuo)時阻(zu)止介質外漏，彈(dan)簧可起補償(chang)作(zuo)用(yong)。

　　填(tian)(tian)料(liao)裝入填(tian)(tian)料(liao)腔(qiang)以后(hou)，經壓蓋螺絲(si)對它作軸(zhou)(zhou)向(xiang)(xiang)壓縮，當軸(zhou)(zhou)與(yu)(yu)(yu)填(tian)(tian)料(liao)有相對運動時，由于填(tian)(tian)料(liao)的(de)(de)(de)塑性，使(shi)它產生徑向(xiang)(xiang)力，并與(yu)(yu)(yu)軸(zhou)(zhou)緊密(mi)接(jie)(jie)(jie)觸(chu)(chu)(chu)。與(yu)(yu)(yu)此同時，填(tian)(tian)料(liao)中(zhong)浸(jin)漬的(de)(de)(de)潤(run)(run)滑(hua)劑被擠出，在接(jie)(jie)(jie)觸(chu)(chu)(chu)面之間形(xing)成(cheng)油膜(mo)(mo)。由于接(jie)(jie)(jie)觸(chu)(chu)(chu)狀態(tai)(tai)并不(bu)是(shi)特別均勻的(de)(de)(de)，接(jie)(jie)(jie)觸(chu)(chu)(chu)部(bu)位(wei)(wei)(wei)便出現“邊界潤(run)(run)滑(hua)”狀態(tai)(tai)，稱(cheng)為(wei)“軸(zhou)(zhou)承(cheng)(cheng)效(xiao)(xiao)應(ying)”；而未(wei)接(jie)(jie)(jie)觸(chu)(chu)(chu)的(de)(de)(de)凹部(bu)形(xing)成(cheng)小油槽，有較厚的(de)(de)(de)油膜(mo)(mo)，接(jie)(jie)(jie)觸(chu)(chu)(chu)部(bu)位(wei)(wei)(wei)與(yu)(yu)(yu)非(fei)接(jie)(jie)(jie)觸(chu)(chu)(chu)部(bu)位(wei)(wei)(wei)組成(cheng)一道不(bu)規則的(de)(de)(de)迷(mi)宮，起阻止液流泄漏的(de)(de)(de)作用，此稱(cheng)“迷(mi)宮效(xiao)(xiao)應(ying)”。這就是(shi)填(tian)(tian)料(liao)密(mi)封的(de)(de)(de)機理。顯然，良(liang)好(hao)的(de)(de)(de)密(mi)封在于維(wei)持“軸(zhou)(zhou)承(cheng)(cheng)效(xiao)(xiao)應(ying)”和“迷(mi)宮效(xiao)(xiao)應(ying)”。也就是(shi)說，要保(bao)持良(liang)好(hao)的(de)(de)(de)潤(run)(run)滑(hua)和適當的(de)(de)(de)壓緊。若(ruo)潤(run)(run)滑(hua)不(bu)良(liang)，或壓得過緊都會使(shi)油膜(mo)(mo)中(zhong)斷，造成(cheng)填(tian)(tian)料(liao)與(yu)(yu)(yu)軸(zhou)(zhou)之間出現干摩(mo)擦(ca)，最后(hou)導致燒軸(zhou)(zhou)和出現嚴重磨損。

　　為此(ci)，需要(yao)經常對填(tian)(tian)(tian)料(liao)(liao)的壓緊(jin)程度進行調整，以便填(tian)(tian)(tian)料(liao)(liao)中的潤滑劑在(zai)運行一段時間(jian)流失之后(hou)，再(zai)擠出一些(xie)潤滑劑，同(tong)時補償填(tian)(tian)(tian)料(liao)(liao)因(yin)體積變化所造成的壓緊(jin)力松弛。顯然(ran)，這樣經常擠壓填(tian)(tian)(tian)料(liao)(liao)，最終將使浸漬劑枯竭，所以定期更換填(tian)(tian)(tian)料(liao)(liao)是必要(yao)的。此(ci)外，為了維持液(ye)膜和(he)帶走(zou)摩擦(ca)熱，有(you)(you)意讓填(tian)(tian)(tian)料(liao)(liao)處有(you)(you)少(shao)量泄漏也是必要(yao)的。