卡特挖掘機維修
CAT320B型挖掘機該機在施工過程中突然出現整機各人動作均異常緩慢（如空載回轉一圈需13s）的現象，而滿負荷運轉時，發動機轉速正常，煙色也正常。針對故障現象進行分析后，基本上可以排除來自發動機的原因，斷定故障出自液壓系統，可能是因液壓泵自身的機械故障造內泄嚴重，也可能是系統壓力不夠。別外，也可能是功率模式設定不正確。320B型液壓挖掘機設計有3種不同的功率模式：重載模式、普通模式，以及精細模式。液村系統所吸收的發動機功率分別是100%、90%和75%，如果將功率模式設置在精細模式，就有可能造成機器的動作緩慢。先導泵是為先導系統提供壓力油的，先導系統的作用之一就是控制主油路，使之完成相應的動作挖掘機維修,挖掘機修理,維修挖掘機,修理挖掘機。
如(ru)果該(gai)系(xi)統(tong)(tong)出(chu)(chu)現故障(zhang)，先導系(xi)統(tong)(tong)統(tong)(tong)壓(ya)力過(guo)低，使(shi)先導油無(wu)法對(dui)主(zhu)(zhu)(zhu)控(kong)(kong)(kong)閥(fa)進(jin)行相應(ying)的(de)(de)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)或主(zhu)(zhu)(zhu)控(kong)(kong)(kong)閥(fa)閥(fa)芯(xin)行程過(guo)小(xiao)，從(cong)(cong)而使(shi)主(zhu)(zhu)(zhu)油路流量不(bu)足，也可能導致機(ji)器動作(zuo)過(guo)緩。主(zhu)(zhu)(zhu)泵電子(zi)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)系(xi)統(tong)(tong)如(ru)果出(chu)(chu)現故障(zhang)，也可引起(qi)上述整(zheng)機(ji)的(de)(de)故障(zhang)現象(xiang)，對(dui)此，可按附圖排(pai)查。電子(zi)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)系(xi)統(tong)(tong)通過(guo)主(zhu)(zhu)(zhu)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)器來控(kong)(kong)(kong)制(zhi)(zhi)(zhi)主(zhu)(zhu)(zhu)液(ye)壓(ya)泵從(cong)(cong)發動機(ji)吸收(shou)(shou)的(de)(de)功(gong)(gong)率(lv)(lv)，使(shi)發動機(ji)輸(shu)出(chu)(chu)功(gong)(gong)率(lv)(lv)與(yu)液(ye)壓(ya)泵吸收(shou)(shou)的(de)(de)功(gong)(gong)率(lv)(lv)相匹(pi)配，以適應(ying)不(bu)同的(de)(de)工作(zuo)環境(jing)。電子(zi)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)系(xi)統(tong)(tong)的(de)(de)主(zhu)(zhu)(zhu)要功(gong)(gong)能是：當機(ji)器負(fu)載(zai)很大時(shi)，系(xi)統(tong)(tong)使(shi)液(ye)壓(ya)泵有(you)較(jiao)大的(de)(de)排(pai)量，使(shi)之輸(shu)出(chu)(chu)與(yu)發動機(ji)相匹(pi)配的(de)(de)最(zui)大功(gong)(gong)率(lv)(lv)；根據負(fu)載(zai)情(qing)況(kuang)，系(xi)統(tong)(tong)有(you)3種不(bu)同的(de)(de)功(gong)(gong)率(lv)(lv)模式(shi)，將液(ye)壓(ya)泵的(de)(de)輸(shu)出(chu)(chu)功(gong)(gong)率(lv)(lv)控(kong)(kong)(kong)制(zhi)(zhi)(zhi)在最(zui)佳狀態，減少燃油消(xiao)耗(hao)；空載(zai)或負(fu)荷很小(xiao)時(shi)，系(xi)統(tong)(tong)自(zi)動降(jiang)低發動機(ji)的(de)(de)轉速(su)并使(shi)主(zhu)(zhu)(zhu)泵排(pai)量減至最(zui)小(xiao)，可達到節能、降(jiang)耗(hao)且降(jiang)低噪聲。
電子(zi)(zi)(zi)控(kong)(kong)制(zhi)(zhi)系(xi)(xi)統(tong)的(de)(de)工作(zuo)(zuo)過程：電子(zi)(zi)(zi)控(kong)(kong)制(zhi)(zhi)系(xi)(xi)統(tong)的(de)(de)主(zhu)(zhu)要部件——主(zhu)(zhu)控(kong)(kong)制(zhi)(zhi)器接(jie)收(shou)來(lai)自(zi)各方面的(de)(de)輸入信號(hao)（如(ru)，油(you)門旋鈕的(de)(de)位置(zhi)(zhi)、監控(kong)(kong)器設置(zhi)(zhi)功(gong)率模式(shi)、主(zhu)(zhu)泵(beng)壓(ya)(ya)(ya)力傳(chuan)(chuan)感器傳(chuan)(chuan)回(hui)(hui)的(de)(de)壓(ya)(ya)(ya)力信號(hao)、油(you)門馬(ma)達(da)的(de)(de)位置(zhi)(zhi)傳(chuan)(chuan)回(hui)(hui)的(de)(de)壓(ya)(ya)(ya)力信號(hao)、油(you)門馬(ma)達(da)的(de)(de)位置(zhi)(zhi)傳(chuan)(chuan)感器信號(hao)，以及發動(dong)(dong)機速(su)度傳(chuan)(chuan)感器信號(hao)等）。主(zhu)(zhu)控(kong)(kong)制(zhi)(zhi)器處理這些輸入信號(hao)后，輸出(chu)指令給(gei)發動(dong)(dong)機的(de)(de)油(you)門馬(ma)達(da)和主(zhu)(zhu)液(ye)壓(ya)(ya)(ya)泵(beng)的(de)(de)主(zhu)(zhu)要控(kong)(kong)制(zhi)(zhi)部件——比(bi)例(li)減壓(ya)(ya)(ya)閥。油(you)門馬(ma)達(da)的(de)(de)相應動(dong)(dong)作(zuo)(zuo)可以改變發動(dong)(dong)機的(de)(de)轉速(su)，而比(bi)例(li)減壓(ya)(ya)(ya)閥的(de)(de)動(dong)(dong)作(zuo)(zuo)則可調節(jie)泵(beng)的(de)(de)排量(liang)，二(er)者在主(zhu)(zhu)控(kong)(kong)制(zhi)(zhi)器的(de)(de)控(kong)(kong)制(zhi)(zhi)下，使發動(dong)(dong)機和液(ye)壓(ya)(ya)(ya)系(xi)(xi)統(tong)達(da)到最佳匹(pi)配。因此，只要電子(zi)(zi)(zi)控(kong)(kong)制(zhi)(zhi)系(xi)(xi)統(tong)任何部位出(chu)現問題(ti)，都可能使機器無(wu)常工作(zuo)(zuo)。液(ye)壓(ya)(ya)(ya)泵(beng)自(zi)身調節(jie)系(xi)(xi)統(tong)有故(gu)障，可能是液(ye)壓(ya)(ya)(ya)泵(beng)調節(jie)器或(huo)者控(kong)(kong)制(zhi)(zhi)信號(hao)油(you)壓(ya)(ya)(ya)出(chu)現故(gu)障所致。
排(pai)除故障(zhang)的(de)(de)(de)方法(fa)是，根據上(shang)述分析，依次(ci)進行了相應的(de)(de)(de)檢查(cha)。大家知道，如果液(ye)壓(ya)(ya)(ya)系統(tong)(tong)有(you)故障(zhang)，不(bu)能(neng)再輕易在啟動發(fa)動機(ji)，因為(wei)那樣就有(you)可能(neng)造成某(mou)些(xie)液(ye)壓(ya)(ya)(ya)部件進一步地(di)損(sun)壞，從而(er)(er)污染整個液(ye)壓(ya)(ya)(ya)系統(tong)(tong)。故首先(xian)檢查(cha)了液(ye)壓(ya)(ya)(ya)油(you)(you)箱(xiang)的(de)(de)(de)油(you)(you)位(wei)，發(fa)現(xian)(xian)(xian)油(you)(you)位(wei)正(zheng)常；進而(er)(er)取出液(ye)壓(ya)(ya)(ya)油(you)(you)箱(xiang)中的(de)(de)(de)主回油(you)(you)濾芯以及(ji)殼體泄(xie)油(you)(you)濾芯和先(xian)導(dao)油(you)(you)濾芯，并(bing)(bing)逐一剖開檢查(cha)，看是否有(you)銅屑等異物，檢查(cha)結果是3個濾清器均(jun)正(zheng)常。于是，裝上(shang)新的(de)(de)(de)濾芯，啟動發(fa)動機(ji)并(bing)(bing)以怠(dai)速(su)運轉，傾聽液(ye)壓(ya)(ya)(ya)泵的(de)(de)(de)聲音，結果液(ye)壓(ya)(ya)(ya)泵并(bing)(bing)無異響；再測量系統(tong)(tong)壓(ya)(ya)(ya)力，得到主安全閥的(de)(de)(de)溢流壓(ya)(ya)(ya)力為(wei)34.3MPa，即系統(tong)(tong)壓(ya)(ya)(ya)力正(zheng)常。因此，可排(pai)除液(ye)壓(ya)(ya)(ya)泵出現(xian)(xian)(xian)機(ji)械損(sun)壞的(de)(de)(de)結論。重新設置功(gong)率(lv)模(mo)式(shi)于重載模(mo)式(shi)，試機(ji)，動作依然緩慢，以此可以排(pai)除因功(gong)率(lv)模(mo)式(shi)設置不(bu)正(zheng)確(que)而(er)(er)出現(xian)(xian)(xian)故障(zhang)的(de)(de)(de)可能(neng)原因。
測試先導(dao)壓力，其(qi)值為4.1MPa，屬正(zheng)(zheng)常。因(yin)此(ci)(ci)(ci)，可(ke)(ke)(ke)以排除(chu)先導(dao)系統出現故障(zhang)的(de)(de)可(ke)(ke)(ke)能性。于是(shi)，驗證電子(zi)控(kong)制(zhi)系統是(shi)否出現故障(zhang)。此(ci)(ci)(ci)故障(zhang)的(de)(de)判斷(duan)方法(fa)比較簡單，因(yin)為系統上(shang)(shang)設置有手動(dong)備用開關，當主(zhu)(zhu)控(kong)制(zhi)器(qi)或監(jian)控(kong)器(qi)出現問(wen)題時，將(jiang)備用開關扳(ban)至(zhi)手動(dong)位置，可(ke)(ke)(ke)使機器(qi)繼續工作(zuo)(zuo)。按上(shang)(shang)述方法(fa)操作(zuo)(zuo)機器(qi)，結果動(dong)作(zuo)(zuo)依然緩慢。故可(ke)(ke)(ke)初步認為主(zhu)(zhu)控(kong)制(zhi)器(qi)正(zheng)(zheng)常；后又將(jiang)開關反扳(ban)回自動(dong)位置，再(zai)檢驗主(zhu)(zhu)控(kong)制(zhi)器(qi)上(shang)(shang)的(de)(de)3個(ge)發光二(er)極管(guan)，見3個(ge)二(er)極管(guan)均為綠光，再(zai)次證明主(zhu)(zhu)控(kong)制(zhi)器(qi)以及(ji)主(zhu)(zhu)控(kong)制(zhi)器(qi)與監(jian)控(kong)器(qi)之(zhi)間的(de)(de)通信(xin)線路正(zheng)(zheng)常。卡特彼(bi)勒(le)公司的(de)(de)挖掘機上(shang)(shang)監(jian)控(kong)系統有很強的(de)(de)自檢及(ji)數據(ju)記憶功(gong)能，因(yin)此(ci)(ci)(ci)，我們可(ke)(ke)(ke)以通過監(jian)控(kong)器(qi)了解其(qi)他電子(zi)元件的(de)(de)狀態(tai)和數據(ju)，從(cong)而判斷(duan)它們工作(zuo)(zuo)是(shi)否正(zheng)(zheng)常。從(cong)監(jian)控(kong)器(qi)上(shang)(shang)輸入密碼(ma)后。
進入卡特(te)彼勒的(de)(de)維修模式，先檢查(cha)稆種(zhong)開(kai)關(guan)的(de)(de)狀(zhuang)態(tai)，結(jie)果表(biao)明(ming)各(ge)種(zhong)開(kai)關(guan)均(jun)處于正常狀(zhuang)態(tai)位置；然后檢查(cha)發動機額定(ding)轉速(su)以及泵(beng)在主安(an)全閥泄流(liu)時(shi)的(de)(de)壓(ya)力，監(jian)控器顯(xian)示(shi)這(zhe)項數據(ju)為(wei)1800r/min和34.3MPa，均(jun)為(wei)正常值；檢查(cha)比(bi)例(li)減速(su)壓(ya)閥的(de)(de)壓(ya)力變(bian)(bian)化(hua)范圍(wei)，在正常的(de)(de)操作過(guo)(guo)程中，監(jian)控器顯(xian)示(shi)比(bi)便減壓(ya)閥的(de)(de)壓(ya)力變(bian)(bian)化(hua)范圍(wei)為(wei)3.2~0.76MPa，即比(bi)例(li)減壓(ya)閥的(de)(de)壓(ya)力變(bian)(bian)化(hua)正常。再查(cha)盾現(xian)實故(gu)障代碼和以前記錄的(de)(de)故(gu)障代碼，監(jian)控器均(jun)未顯(xian)示(shi)何故(gu)障代碼，至此可(ke)以肯(ken)定(ding)，問題不(bu)是出在電子(zi)控制(zhi)系統。最后，檢查(cha)液壓(ya)泵(beng)自身調(diao)(diao)節(jie)系統。其(qi)上、下泵(beng)的(de)(de)調(diao)(diao)節(jie)器是分開(kai)的(de)(de)，通過(guo)(guo)對左、右單邊(bian)行(xing)走(zou)的(de)(de)測試表(biao)時(shi)均(jun)存(cun)在問題，由(you)于兩泵(beng)調(diao)(diao)節(jie)器均(jun)出現(xian)故(gu)障的(de)(de)可(ke)能性較小，我們先將其(qi)放(fang)在一(yi)邊(bian)。
從外部著(zhu)看查起。液壓(ya)(ya)(ya)泵(beng)(beng)調節器(qi)的(de)外部控(kong)(kong)(kong)制(zhi)信號(hao)有兩個(ge)：一(yi)個(ge)取(qu)自(zi)主(zhu)控(kong)(kong)(kong)閥(fa)中(zhong)心油道的(de)壓(ya)(ya)(ya)力(li)PN，上(shang)、下(xia)泵(beng)(beng)各一(yi)；另一(yi)個(ge)是(shi)來自(zi)同時控(kong)(kong)(kong)制(zhi)上(shang)、下(xia)泵(beng)(beng)的(de)比例減(jian)(jian)(jian)壓(ya)(ya)(ya)閥(fa)的(de)壓(ya)(ya)(ya)力(li)PS。先分別測量(liang)上(shang)、下(xia)泵(beng)(beng)的(de)壓(ya)(ya)(ya)力(li)PN值(zhi)(zhi)，得到當主(zhu)控(kong)(kong)(kong)閥(fa)中(zhong)位時壓(ya)(ya)(ya)力(li)為4.07MPa，無論有任何一(yi)下(xia)動作，PN即下(xia)降為0.35MPa，PN值(zhi)(zhi)正常。再測量(liang)PS值(zhi)(zhi)，雖(sui)然已經通過監(jian)控(kong)(kong)(kong)器(qi)已查看到了PS值(zhi)(zhi)的(de)變(bian)化范圍(wei)，且其壓(ya)(ya)(ya)力(li)變(bian)化值(zhi)(zhi)正常，但這并不(bu)一(yi)定準確(que)，因為比例減(jian)(jian)(jian)壓(ya)(ya)(ya)閥(fa)上(shang)并沒(mei)有壓(ya)(ya)(ya)力(li)傳感器(qi)直(zhi)接給(gei)主(zhu)控(kong)(kong)(kong)制(zhi)器(qi)經信號(hao)輸(shu)入，監(jian)控(kong)(kong)(kong)器(qi)顯示的(de)壓(ya)(ya)(ya)力(li)值(zhi)(zhi)是(shi)主(zhu)控(kong)(kong)(kong)制(zhi)器(qi)通過對比例減(jian)(jian)(jian)壓(ya)(ya)(ya)閥(fa)的(de)輸(shu)出(chu)電流信號(hao)經分析轉換而(er)成的(de)、也就是(shi)說，此壓(ya)(ya)(ya)力(li)值(zhi)(zhi)對應主(zhu)控(kong)(kong)(kong)制(zhi)器(qi)對比例減(jian)(jian)(jian)壓(ya)(ya)(ya)閥(fa)輸(shu)出(chu)電流的(de)強弱。為此，在(zai)泵(beng)(beng)體(ti)上(shang)的(de)PS壓(ya)(ya)(ya)力(li)側(ce)點接上(shang)壓(ya)(ya)(ya)力(li)表。
