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發布(bu)時間:2021-12-10 15:52:26 人(ren)氣:128117 來源:
填(tian)(tian)(tian)料(liao)(liao)(liao)改集(ji)式密封是指(zhi)通過預(yu)緊(jin)或(huo)介質壓力(li)的(de)自(zi)緊(jin)作(zuo)用(yong)(yong)(yong)使填(tian)(tian)(tian)料(liao)(liao)(liao)與轉動件及固定(ding)件之間產(chan)生(sheng)壓緊(jin)力(li)的(de)動密封裝置(zhi)(zhi)。又稱(cheng)“填(tian)(tian)(tian)料(liao)(liao)(liao)函密封”。結構形式較多(duo),主要由填(tian)(tian)(tian)料(liao)(liao)(liao)、填(tian)(tian)(tian)料(liao)(liao)(liao)箱和填(tian)(tian)(tian)料(liao)(liao)(liao)固定(ding)件組成。常用(yong)(yong)(yong)的(de)填(tian)(tian)(tian)料(liao)(liao)(liao)材料(liao)(liao)(liao)有(you)石(shi)棉織物(wu)、碳纖維(wei)、橡膠(jiao)、柔性(xing)石(shi)墨和工(gong)(gong)程塑(su)料(liao)(liao)(liao)等,預(yu)制成環狀(zhuang)(zhuang)或(huo)條狀(zhuang)(zhuang)(有(you)的(de)需(xu)預(yu)先浸漬潤滑性(xing)好的(de)填(tian)(tian)(tian)充物(wu)),并采(cai)用(yong)(yong)(yong)多(duo)環或(huo)螺旋狀(zhuang)(zhuang)多(duo)層結構。填(tian)(tian)(tian)料(liao)(liao)(liao)箱用(yong)(yong)(yong)以安置(zhi)(zhi)填(tian)(tian)(tian)料(liao)(liao)(liao)。填(tian)(tian)(tian)料(liao)(liao)(liao)固定(ding)件包(bao)括壓蓋、螺栓和彈(dan)簧(huang)等,用(yong)(yong)(yong)以使填(tian)(tian)(tian)料(liao)(liao)(liao)預(yu)緊(jin),工(gong)(gong)作(zuo)時阻止介質外漏,彈(dan)簧(huang)可(ke)起補償作(zuo)用(yong)(yong)(yong)。
填(tian)(tian)料裝入填(tian)(tian)料腔以后,經壓(ya)蓋(gai)螺絲對它(ta)作軸(zhou)向(xiang)壓(ya)縮,當(dang)軸(zhou)與(yu)填(tian)(tian)料有相對運動時,由于填(tian)(tian)料的(de)(de)(de)(de)(de)塑性(xing),使(shi)(shi)它(ta)產(chan)生徑向(xiang)力,并與(yu)軸(zhou)緊密接(jie)(jie)觸。與(yu)此同時,填(tian)(tian)料中浸漬的(de)(de)(de)(de)(de)潤滑(hua)(hua)劑被擠出(chu)(chu),在接(jie)(jie)觸面之(zhi)間形成(cheng)油膜。由于接(jie)(jie)觸狀態并不是特別均勻的(de)(de)(de)(de)(de),接(jie)(jie)觸部(bu)(bu)位便出(chu)(chu)現“邊(bian)界潤滑(hua)(hua)”狀態,稱為“軸(zhou)承(cheng)效(xiao)(xiao)應(ying)”;而未接(jie)(jie)觸的(de)(de)(de)(de)(de)凹(ao)部(bu)(bu)形成(cheng)小(xiao)油槽(cao),有較厚的(de)(de)(de)(de)(de)油膜,接(jie)(jie)觸部(bu)(bu)位與(yu)非接(jie)(jie)觸部(bu)(bu)位組成(cheng)一(yi)道不規則的(de)(de)(de)(de)(de)迷宮(gong),起阻止液流泄漏的(de)(de)(de)(de)(de)作用(yong),此稱“迷宮(gong)效(xiao)(xiao)應(ying)”。這就是填(tian)(tian)料密封的(de)(de)(de)(de)(de)機(ji)理。顯然,良好的(de)(de)(de)(de)(de)密封在于維持(chi)“軸(zhou)承(cheng)效(xiao)(xiao)應(ying)”和(he)“迷宮(gong)效(xiao)(xiao)應(ying)”。也就是說,要保持(chi)良好的(de)(de)(de)(de)(de)潤滑(hua)(hua)和(he)適當(dang)的(de)(de)(de)(de)(de)壓(ya)緊。若潤滑(hua)(hua)不良,或(huo)壓(ya)得過緊都會使(shi)(shi)油膜中斷(duan),造成(cheng)填(tian)(tian)料與(yu)軸(zhou)之(zhi)間出(chu)(chu)現干摩(mo)擦(ca),最(zui)后導致燒軸(zhou)和(he)出(chu)(chu)現嚴重磨損(sun)。
為此(ci),需(xu)要經(jing)常(chang)對填(tian)料(liao)(liao)(liao)的(de)(de)(de)壓(ya)緊(jin)程(cheng)度進行(xing)(xing)調整(zheng),以便填(tian)料(liao)(liao)(liao)中的(de)(de)(de)潤滑劑在運行(xing)(xing)一段時(shi)間流(liu)失之后,再擠出一些潤滑劑,同時(shi)補償填(tian)料(liao)(liao)(liao)因(yin)體積變(bian)化所造(zao)成的(de)(de)(de)壓(ya)緊(jin)力松弛。顯然,這樣(yang)經(jing)常(chang)擠壓(ya)填(tian)料(liao)(liao)(liao),最終將使浸漬(zi)劑枯竭,所以定期更(geng)換填(tian)料(liao)(liao)(liao)是(shi)必要的(de)(de)(de)。此(ci)外,為了維持液膜和帶走摩擦熱,有(you)意(yi)讓填(tian)料(liao)(liao)(liao)處有(you)少量泄漏也是(shi)必要的(de)(de)(de)。