工(gong)程(cheng)機械與(yu)維(wei)修(xiu)(xiu)若挖掘機出(chu)(chu)現(xian)(xian)(xian)小故(gu)障(zhang)(zhang)后維(wei)修(xiu)(xiu)不當，不僅不能(neng)(neng)排(pai)除故(gu)障(zhang)(zhang)，還可(ke)(ke)造成挖掘機無常(chang)(chang)工(gong)作，甚至導致挖掘機使(shi)用壽命縮短、過早進行大修(xiu)(xiu)。因(yin)此(ci)(ci)，當挖掘機液壓(ya)系(xi)統(tong)(tong)出(chu)(chu)現(xian)(xian)(xian)故(gu)障(zhang)(zhang)必須認真分(fen)析(xi)(xi)及時(shi)排(pai)除。修(xiu)(xiu)哥(ge)今(jin)兒(er)就說一個挖掘機動(dong)(dong)臂(bei)提(ti)升(sheng)(sheng)故(gu)障(zhang)(zhang)出(chu)(chu)現(xian)(xian)(xian)后的(de)分(fen)析(xi)(xi)實例(li)，希(xi)望大家有(you)(you)所借(jie)鑒。一臺挖掘機操縱動(dong)(dong)臂(bei)提(ti)升(sheng)(sheng)時(shi)，出(chu)(chu)現(xian)(xian)(xian)提(ti)升(sheng)(sheng)速度(du)(du)比正(zheng)常(chang)(chang)速度(du)(du)明顯緩慢，其(qi)他動(dong)(dong)作均正(zheng)常(chang)(chang)。此(ci)(ci)時(shi)不用惶恐，先分(fen)析(xi)(xi)排(pai)查，然(ran)后必能(neng)(neng)找(zhao)出(chu)(chu)故(gu)障(zhang)(zhang)原(yuan)因(yin)得(de)以解決(jue)。1.分(fen)析(xi)(xi)故(gu)障(zhang)(zhang)原(yuan)因(yin)按照(zhao)其(qi)液壓(ya)系(xi)統(tong)(tong)原(yuan)理分(fen)析(xi)(xi)，只是(shi)動(dong)(dong)臂(bei)提(ti)升(sheng)(sheng)動(dong)(dong)作緩慢，可(ke)(ke)排(pai)除多個動(dong)(dong)作公(gong)用元件出(chu)(chu)現(xian)(xian)(xian)故(gu)障(zhang)(zhang)的(de)可(ke)(ke)能(neng)(neng)，因(yin)此(ci)(ci)可(ke)(ke)將故(gu)障(zhang)(zhang)范圍縮小到(dao)與(yu)動(dong)(dong)臂(bei)提(ti)升(sheng)(sheng)相關(guan)的(de)先導油(you)路和工(gong)作油(you)路范圍內(nei)。與(yu)動(dong)(dong)臂(bei)提(ti)升(sheng)(sheng)有(you)(you)關(guan)的(de)液壓(ya)原(yuan)件有(you)(you)動(dong)(dong)臂(bei)Ⅱ閥動(dong)(dong)臂(bei)缸動(dong)(dong)臂(bei)保持閥動(dong)(dong)臂(bei)提(ti)升(sheng)(sheng)過載(zai)溢流閥12。
如圖1所(suo)示。動(dong)(dong)(dong)(dong)臂(bei)(bei)(bei)(bei)(bei)提(ti)(ti)升緩慢與(yu)這些元件(jian)(jian)通過(guo)的(de)液(ye)壓油流量減小有(you)關，圖1中用(yong)彩色(se)線條畫出了動(dong)(dong)(dong)(dong)臂(bei)(bei)(bei)(bei)(bei)提(ti)(ti)升時的(de)工作(zuo)(zuo)油路。從圖1中可以看出，引起流量減小的(de)原因(yin)可能有(you)以下(xia)(xia)5點：一(yi)是動(dong)(dong)(dong)(dong)臂(bei)(bei)(bei)(bei)(bei)缸(gang)8內泄，二是動(dong)(dong)(dong)(dong)臂(bei)(bei)(bei)(bei)(bei)保(bao)(bao)持閥(fa)11故(gu)障(zhang)，三是動(dong)(dong)(dong)(dong)臂(bei)(bei)(bei)(bei)(bei)提(ti)(ti)升過(guo)載溢流閥(fa)12故(gu)障(zhang)，四是動(dong)(dong)(dong)(dong)臂(bei)(bei)(bei)(bei)(bei)提(ti)(ti)升先(xian)導壓力低，五是動(dong)(dong)(dong)(dong)臂(bei)(bei)(bei)(bei)(bei)Ⅰ閥(fa)14或動(dong)(dong)(dong)(dong)臂(bei)(bei)(bei)(bei)(bei)Ⅱ閥(fa)5卡(ka)滯(zhi)。故(gu)障(zhang)排查(cha)(cha)（1）檢查(cha)(cha)動(dong)(dong)(dong)(dong)臂(bei)(bei)(bei)(bei)(bei)缸(gang)如果動(dong)(dong)(dong)(dong)臂(bei)(bei)(bei)(bei)(bei)缸(gang)內泄，一(yi)般伴(ban)有(you)動(dong)(dong)(dong)(dong)臂(bei)(bei)(bei)(bei)(bei)自然下(xia)(xia)沉現象。我們請操作(zuo)(zuo)人員將動(dong)(dong)(dong)(dong)臂(bei)(bei)(bei)(bei)(bei)舉升后(hou)停止(zhi)，檢查(cha)(cha)動(dong)(dong)(dong)(dong)臂(bei)(bei)(bei)(bei)(bei)沒有(you)明(ming)顯下(xia)(xia)沉現象。用(yong)動(dong)(dong)(dong)(dong)臂(bei)(bei)(bei)(bei)(bei)下(xia)(xia)降方法(fa)支(zhi)起挖掘機，支(zhi)撐動(dong)(dong)(dong)(dong)作(zuo)(zuo)有(you)力，由此排除動(dong)(dong)(dong)(dong)臂(bei)(bei)(bei)(bei)(bei)缸(gang)內泄的(de)可能，同時也說明(ming)動(dong)(dong)(dong)(dong)臂(bei)(bei)(bei)(bei)(bei)Ⅰ閥(fa)、動(dong)(dong)(dong)(dong)臂(bei)(bei)(bei)(bei)(bei)Ⅱ閥(fa)閥(fa)芯工作(zuo)(zuo)正常(chang)。（2）檢查(cha)(cha)動(dong)(dong)(dong)(dong)臂(bei)(bei)(bei)(bei)(bei)保(bao)(bao)持閥(fa)該機動(dong)(dong)(dong)(dong)臂(bei)(bei)(bei)(bei)(bei)保(bao)(bao)持閥(fa)與(yu)斗桿保(bao)(bao)持閥(fa)結構相同，（斗桿保(bao)(bao)持閥(fa)工作(zuo)(zuo)正常(chang)），為了在檢查(cha)(cha)過(guo)程(cheng)中盡量少拆解(jie)元件(jian)(jian)。
我們將(jiang)動臂(bei)(bei)(bei)(bei)保(bao)持(chi)閥(fa)(fa)與(yu)斗(dou)桿保(bao)持(chi)閥(fa)(fa)互換(huan)安裝(zhuang)，以此(ci)進行對比(bi)試驗(yan)，結果故(gu)(gu)障(zhang)(zhang)現象沒有改變(bian)，由(you)此(ci)排除了動臂(bei)(bei)(bei)(bei)保(bao)持(chi)閥(fa)(fa)存在故(gu)(gu)障(zhang)(zhang)的(de)(de)可能(neng)。動臂(bei)(bei)(bei)(bei)提(ti)(ti)升(sheng)(sheng)壓(ya)(ya)(ya)力取決于主(zhu)溢(yi)流閥(fa)(fa)（設(she)定(ding)壓(ya)(ya)(ya)力為32.0MPa）和動臂(bei)(bei)(bei)(bei)提(ti)(ti)升(sheng)(sheng)過(guo)(guo)載(zai)(zai)(zai)溢(yi)流閥(fa)(fa)（設(she)定(ding)壓(ya)(ya)(ya)力為35.0MPa）。將(jiang)動臂(bei)(bei)(bei)(bei)提(ti)(ti)升(sheng)(sheng)到頂后(hou)繼續提(ti)(ti)升(sheng)(sheng)，使動臂(bei)(bei)(bei)(bei)提(ti)(ti)升(sheng)(sheng)過(guo)(guo)載(zai)(zai)(zai)溢(yi)流閥(fa)(fa)溢(yi)流，此(ci)時測量主(zhu)泵中的(de)(de)前泵壓(ya)(ya)(ya)力為21.2MPa，后(hou)泵壓(ya)(ya)(ya)力為15.6MPa，這說明該壓(ya)(ya)(ya)力值過(guo)(guo)低。因(yin)該機其他動作正常，說明主(zhu)溢(yi)流閥(fa)(fa)正常。由(you)此(ci)初步判斷動臂(bei)(bei)(bei)(bei)提(ti)(ti)升(sheng)(sheng)過(guo)(guo)載(zai)(zai)(zai)溢(yi)流閥(fa)(fa)存在故(gu)(gu)障(zhang)(zhang)的(de)(de)可能(neng)性(xing)較大，用功能(neng)正常的(de)(de)鏟斗(dou)過(guo)(guo)載(zai)(zai)(zai)溢(yi)流閥(fa)(fa)與(yu)動臂(bei)(bei)(bei)(bei)提(ti)(ti)升(sheng)(sheng)過(guo)(guo)載(zai)(zai)(zai)溢(yi)流閥(fa)(fa)互換(huan)（這2個(ge)閥(fa)(fa)的(de)(de)結構(gou)及調定(ding)壓(ya)(ya)(ya)力相同），故(gu)(gu)障(zhang)(zhang)現象依舊，這說明動臂(bei)(bei)(bei)(bei)提(ti)(ti)升(sheng)(sheng)過(guo)(guo)載(zai)(zai)(zai)溢(yi)流閥(fa)(fa)無(wu)故(gu)(gu)障(zhang)(zhang)。檢查(cha)動臂(bei)(bei)(bei)(bei)提(ti)(ti)升(sheng)(sheng)先導(dao)壓(ya)(ya)(ya)力測量先導(dao)泵輸出先導(dao)油壓(ya)(ya)(ya)力（1次壓(ya)(ya)(ya)力）為3.95MPa。
該(gai)壓(ya)(ya)力(li)(li)正(zheng)常。測(ce)量(liang)先(xian)(xian)(xian)導(dao)(dao)(dao)控制閥(fa)(fa)全開啟(qi)狀態，輸至(zhi)動(dong)(dong)(dong)臂(bei)(bei)動(dong)(dong)(dong)作(zuo)(zuo)時(shi)先(xian)(xian)(xian)導(dao)(dao)(dao)壓(ya)(ya)力(li)(li)（二次(ci)(ci)(ci)壓(ya)(ya)力(li)(li)）為(wei)1.78MPa，該(gai)壓(ya)(ya)力(li)(li)較低。將先(xian)(xian)(xian)導(dao)(dao)(dao)手(shou)柄底端連接(jie)(jie)鏟(chan)(chan)斗挖掘(jue)動(dong)(dong)(dong)作(zuo)(zuo)的(de)(de)先(xian)(xian)(xian)導(dao)(dao)(dao)油(you)管與動(dong)(dong)(dong)臂(bei)(bei)提(ti)升的(de)(de)先(xian)(xian)(xian)導(dao)(dao)(dao)油(you)管互(hu)換(huan)，故障(zhang)(zhang)現象并沒(mei)有改變，這說明(ming)先(xian)(xian)(xian)導(dao)(dao)(dao)控制閥(fa)(fa)本身無故障(zhang)(zhang)。在動(dong)(dong)(dong)臂(bei)(bei)Ⅰ閥(fa)(fa)、動(dong)(dong)(dong)臂(bei)(bei)Ⅱ閥(fa)(fa)的(de)(de)端蓋(gai)測(ce)量(liang)推動(dong)(dong)(dong)閥(fa)(fa)芯動(dong)(dong)(dong)作(zuo)(zuo)的(de)(de)先(xian)(xian)(xian)導(dao)(dao)(dao)壓(ya)(ya)力(li)(li)（二次(ci)(ci)(ci)壓(ya)(ya)力(li)(li)）為(wei)1.87MPa，在鏟(chan)(chan)斗閥(fa)(fa)端蓋(gai)測(ce)量(liang)鏟(chan)(chan)斗挖掘(jue)的(de)(de)先(xian)(xian)(xian)導(dao)(dao)(dao)壓(ya)(ya)力(li)(li)（二次(ci)(ci)(ci)壓(ya)(ya)力(li)(li)）為(wei)3.97MPa。測(ce)量(liang)結果說明(ming)推動(dong)(dong)(dong)動(dong)(dong)(dong)臂(bei)(bei)Ⅰ閥(fa)(fa)或(huo)動(dong)(dong)(dong)臂(bei)(bei)Ⅱ閥(fa)(fa)的(de)(de)先(xian)(xian)(xian)導(dao)(dao)(dao)壓(ya)(ya)力(li)(li)（二次(ci)(ci)(ci)壓(ya)(ya)力(li)(li)）在端蓋(gai)處(chu)有泄漏。檢查(cha)動(dong)(dong)(dong)臂(bei)(bei)Ⅰ閥(fa)(fa)和(he)動(dong)(dong)(dong)臂(bei)(bei)Ⅱ閥(fa)(fa)采用由動(dong)(dong)(dong)臂(bei)(bei)Ⅰ閥(fa)(fa)或(huo)動(dong)(dong)(dong)臂(bei)(bei)Ⅱ閥(fa)(fa)分別(bie)(bie)單獨控制動(dong)(dong)(dong)臂(bei)(bei)提(ti)升，判別(bie)(bie)先(xian)(xian)(xian)導(dao)(dao)(dao)壓(ya)(ya)力(li)(li)（二次(ci)(ci)(ci)壓(ya)(ya)力(li)(li)）故障(zhang)(zhang)部位。先(xian)(xian)(xian)在動(dong)(dong)(dong)臂(bei)(bei)Ⅱ閥(fa)(fa)端蓋(gai)上(shang)(shang)連接(jie)(jie)帶(dai)有測(ce)壓(ya)(ya)接(jie)(jie)口的(de)(de)接(jie)(jie)頭，再在接(jie)(jie)頭上(shang)(shang)連接(jie)(jie)壓(ya)(ya)力(li)(li)表，并將動(dong)(dong)(dong)臂(bei)(bei)Ⅰ閥(fa)(fa)的(de)(de)油(you)口暫時(shi)堵死(si)。
當由動(dong)(dong)(dong)(dong)(dong)(dong)臂(bei)(bei)Ⅱ閥(fa)(fa)單獨操縱動(dong)(dong)(dong)(dong)(dong)(dong)臂(bei)(bei)提(ti)升(sheng)時(shi)，測(ce)量先導(dao)壓(ya)(ya)(ya)力(li)(li)（二次壓(ya)(ya)(ya)力(li)(li)）為3.98MPa，動(dong)(dong)(dong)(dong)(dong)(dong)臂(bei)(bei)可以(yi)(yi)提(ti)升(sheng)。以(yi)(yi)同(tong)樣方法測(ce)試動(dong)(dong)(dong)(dong)(dong)(dong)臂(bei)(bei)Ⅰ閥(fa)(fa)，當單獨用(yong)動(dong)(dong)(dong)(dong)(dong)(dong)臂(bei)(bei)Ⅰ控制動(dong)(dong)(dong)(dong)(dong)(dong)臂(bei)(bei)提(ti)升(sheng)時(shi)，測(ce)量先導(dao)壓(ya)(ya)(ya)力(li)(li)（二次壓(ya)(ya)(ya)力(li)(li)）為1.88MPa，這(zhe)說明(ming)動(dong)(dong)(dong)(dong)(dong)(dong)臂(bei)(bei)Ⅰ閥(fa)(fa)端(duan)(duan)蓋處有泄漏。拆卸檢(jian)查(cha)該(gai)(gai)(gai)端(duan)(duan)蓋，沒有發現(xian)明(ming)顯泄漏問題。用(yong)同(tong)型(xing)號另一臺挖(wa)掘(jue)機(ji)的同(tong)一閥(fa)(fa)芯互(hu)換，測(ce)量先導(dao)壓(ya)(ya)(ya)力(li)(li)依然無明(ming)顯故障(zhang)。排(pai)查(cha)到(dao)這(zhe)里，我(wo)們只能詢問駕駛員該(gai)(gai)(gai)機(ji)以(yi)(yi)前此(ci)處是否進行過(guo)修(xiu)理。得知在此(ci)次故障(zhang)之前，該(gai)(gai)(gai)挖(wa)掘(jue)機(ji)曾(ceng)出(chu)現(xian)過(guo)因(yin)動(dong)(dong)(dong)(dong)(dong)(dong)臂(bei)(bei)Ⅰ閥(fa)(fa)芯卡(ka)滯導(dao)致動(dong)(dong)(dong)(dong)(dong)(dong)臂(bei)(bei)無法動(dong)(dong)(dong)(dong)(dong)(dong)作故障(zhang)，由其他維修(xiu)人員進行過(guo)維修(xiu)。維修(xiu)時(shi)對動(dong)(dong)(dong)(dong)(dong)(dong)臂(bei)(bei)Ⅰ閥(fa)(fa)芯及(ji)閥(fa)(fa)孔進行過(guo)修(xiu)磨，修(xiu)磨部位在該(gai)(gai)(gai)閥(fa)(fa)第1環的環狀臺肩(jian)處。該(gai)(gai)(gai)閥(fa)(fa)第1環臺肩(jian)與閥(fa)(fa)芯的間隙起密封、隔(ge)離兩端(duan)(duan)油壓(ya)(ya)(ya)的作用(yong)，臺肩(jian)上端(duan)(duan)面是推(tui)動(dong)(dong)(dong)(dong)(dong)(dong)閥(fa)(fa)芯移(yi)動(dong)(dong)(dong)(dong)(dong)(dong)的先導(dao)壓(ya)(ya)(ya)力(li)(li)油（二次壓(ya)(ya)(ya)力(li)(li)）。