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(guo)該(gai)系(xi)(xi)(xi)統(tong)(tong)(tong)出(chu)(chu)現(xian)故(gu)障(zhang)，先(xian)導(dao)系(xi)(xi)(xi)統(tong)(tong)(tong)統(tong)(tong)(tong)壓(ya)力過(guo)低，使(shi)先(xian)導(dao)油無法對主(zhu)控(kong)閥(fa)進(jin)行(xing)相(xiang)應(ying)的(de)控(kong)制(zhi)或主(zhu)控(kong)閥(fa)閥(fa)芯行(xing)程(cheng)過(guo)小(xiao)(xiao)，從而使(shi)主(zhu)油路流量(liang)不(bu)足，也(ye)可能導(dao)致機(ji)(ji)器動(dong)作過(guo)緩。主(zhu)泵電(dian)子控(kong)制(zhi)系(xi)(xi)(xi)統(tong)(tong)(tong)如(ru)果(guo)出(chu)(chu)現(xian)故(gu)障(zhang)，也(ye)可引起上(shang)述整機(ji)(ji)的(de)故(gu)障(zhang)現(xian)象，對此，可按附圖排(pai)查。電(dian)子控(kong)制(zhi)系(xi)(xi)(xi)統(tong)(tong)(tong)通(tong)過(guo)主(zhu)控(kong)制(zhi)器來控(kong)制(zhi)主(zhu)液(ye)壓(ya)泵從發(fa)動(dong)機(ji)(ji)吸收(shou)(shou)的(de)功(gong)(gong)率(lv)(lv)，使(shi)發(fa)動(dong)機(ji)(ji)輸出(chu)(chu)功(gong)(gong)率(lv)(lv)與液(ye)壓(ya)泵吸收(shou)(shou)的(de)功(gong)(gong)率(lv)(lv)相(xiang)匹(pi)配，以適應(ying)不(bu)同的(de)工作環境。電(dian)子控(kong)制(zhi)系(xi)(xi)(xi)統(tong)(tong)(tong)的(de)主(zhu)要(yao)功(gong)(gong)能是：當機(ji)(ji)器負(fu)載(zai)很大(da)時，系(xi)(xi)(xi)統(tong)(tong)(tong)使(shi)液(ye)壓(ya)泵有較大(da)的(de)排(pai)量(liang)，使(shi)之輸出(chu)(chu)與發(fa)動(dong)機(ji)(ji)相(xiang)匹(pi)配的(de)最(zui)大(da)功(gong)(gong)率(lv)(lv)；根據負(fu)載(zai)情況，系(xi)(xi)(xi)統(tong)(tong)(tong)有3種不(bu)同的(de)功(gong)(gong)率(lv)(lv)模式，將液(ye)壓(ya)泵的(de)輸出(chu)(chu)功(gong)(gong)率(lv)(lv)控(kong)制(zhi)在最(zui)佳(jia)狀態，減(jian)少燃油消耗；空載(zai)或負(fu)荷(he)很小(xiao)(xiao)時，系(xi)(xi)(xi)統(tong)(tong)(tong)自動(dong)降低發(fa)動(dong)機(ji)(ji)的(de)轉速并使(shi)主(zhu)泵排(pai)量(liang)減(jian)至最(zui)小(xiao)(xiao)，可達到節能、降耗且(qie)降低噪聲。
電(dian)子控(kong)制(zhi)(zhi)(zhi)(zhi)系統(tong)的(de)(de)(de)(de)(de)(de)工作(zuo)過(guo)程：電(dian)子控(kong)制(zhi)(zhi)(zhi)(zhi)系統(tong)的(de)(de)(de)(de)(de)(de)主(zhu)(zhu)要部(bu)件——主(zhu)(zhu)控(kong)制(zhi)(zhi)(zhi)(zhi)器(qi)(qi)(qi)(qi)接收來自各(ge)方面的(de)(de)(de)(de)(de)(de)輸入信(xin)號(hao)(hao)（如(ru)，油(you)(you)門(men)旋鈕的(de)(de)(de)(de)(de)(de)位(wei)置、監控(kong)器(qi)(qi)(qi)(qi)設置功率模式、主(zhu)(zhu)泵(beng)(beng)(beng)壓力傳(chuan)感器(qi)(qi)(qi)(qi)傳(chuan)回的(de)(de)(de)(de)(de)(de)壓力信(xin)號(hao)(hao)、油(you)(you)門(men)馬(ma)達的(de)(de)(de)(de)(de)(de)位(wei)置傳(chuan)回的(de)(de)(de)(de)(de)(de)壓力信(xin)號(hao)(hao)、油(you)(you)門(men)馬(ma)達的(de)(de)(de)(de)(de)(de)位(wei)置傳(chuan)感器(qi)(qi)(qi)(qi)信(xin)號(hao)(hao)，以(yi)及(ji)發動機速度傳(chuan)感器(qi)(qi)(qi)(qi)信(xin)號(hao)(hao)等）。主(zhu)(zhu)控(kong)制(zhi)(zhi)(zhi)(zhi)器(qi)(qi)(qi)(qi)處理(li)這些輸入信(xin)號(hao)(hao)后，輸出(chu)指令給發動機的(de)(de)(de)(de)(de)(de)油(you)(you)門(men)馬(ma)達和主(zhu)(zhu)液壓泵(beng)(beng)(beng)的(de)(de)(de)(de)(de)(de)主(zhu)(zhu)要控(kong)制(zhi)(zhi)(zhi)(zhi)部(bu)件——比例減(jian)壓閥。油(you)(you)門(men)馬(ma)達的(de)(de)(de)(de)(de)(de)相應動作(zuo)可(ke)(ke)以(yi)改變發動機的(de)(de)(de)(de)(de)(de)轉速，而比例減(jian)壓閥的(de)(de)(de)(de)(de)(de)動作(zuo)則可(ke)(ke)調(diao)節泵(beng)(beng)(beng)的(de)(de)(de)(de)(de)(de)排量，二者(zhe)在主(zhu)(zhu)控(kong)制(zhi)(zhi)(zhi)(zhi)器(qi)(qi)(qi)(qi)的(de)(de)(de)(de)(de)(de)控(kong)制(zhi)(zhi)(zhi)(zhi)下，使發動機和液壓系統(tong)達到(dao)最(zui)佳匹配。因此，只要電(dian)子控(kong)制(zhi)(zhi)(zhi)(zhi)系統(tong)任何部(bu)位(wei)出(chu)現問題，都可(ke)(ke)能使機器(qi)(qi)(qi)(qi)無常工作(zuo)。液壓泵(beng)(beng)(beng)自身調(diao)節系統(tong)有(you)故障，可(ke)(ke)能是液壓泵(beng)(beng)(beng)調(diao)節器(qi)(qi)(qi)(qi)或(huo)者(zhe)控(kong)制(zhi)(zhi)(zhi)(zhi)信(xin)號(hao)(hao)油(you)(you)壓出(chu)現故障所致。
排除故(gu)(gu)障(zhang)的(de)方法是，根(gen)據(ju)上述分析，依次進(jin)(jin)行了相應(ying)的(de)檢查(cha)(cha)。大(da)家知道，如果液(ye)(ye)壓(ya)(ya)(ya)系(xi)統(tong)有故(gu)(gu)障(zhang)，不能再輕易在啟動發動機，因為那樣就有可(ke)能造成某些液(ye)(ye)壓(ya)(ya)(ya)部件(jian)進(jin)(jin)一步(bu)地(di)損壞，從(cong)而(er)污(wu)染整個液(ye)(ye)壓(ya)(ya)(ya)系(xi)統(tong)。故(gu)(gu)首(shou)先檢查(cha)(cha)了液(ye)(ye)壓(ya)(ya)(ya)油(you)箱的(de)油(you)位，發現(xian)油(you)位正(zheng)常(chang)；進(jin)(jin)而(er)取(qu)出(chu)液(ye)(ye)壓(ya)(ya)(ya)油(you)箱中的(de)主(zhu)回油(you)濾芯(xin)以及殼(ke)體泄油(you)濾芯(xin)和先導(dao)油(you)濾芯(xin)，并逐(zhu)一剖開檢查(cha)(cha)，看是否(fou)有銅屑(xie)等異物，檢查(cha)(cha)結果是3個濾清(qing)器均正(zheng)常(chang)。于是，裝上新(xin)的(de)濾芯(xin)，啟動發動機并以怠速運轉(zhuan)，傾(qing)聽液(ye)(ye)壓(ya)(ya)(ya)泵的(de)聲音，結果液(ye)(ye)壓(ya)(ya)(ya)泵并無異響；再測量系(xi)統(tong)壓(ya)(ya)(ya)力，得(de)到主(zhu)安全閥的(de)溢流壓(ya)(ya)(ya)力為34.3MPa，即系(xi)統(tong)壓(ya)(ya)(ya)力正(zheng)常(chang)。因此(ci)(ci)，可(ke)排除液(ye)(ye)壓(ya)(ya)(ya)泵出(chu)現(xian)機械損壞的(de)結論。重(zhong)新(xin)設(she)置(zhi)功率模(mo)式(shi)于重(zhong)載模(mo)式(shi)，試機，動作依然緩(huan)慢(man)，以此(ci)(ci)可(ke)以排除因功率模(mo)式(shi)設(she)置(zhi)不正(zheng)確而(er)出(chu)現(xian)故(gu)(gu)障(zhang)的(de)可(ke)能原因。
測試先導壓力，其值(zhi)為(wei)(wei)4.1MPa，屬正(zheng)常(chang)。因(yin)此，可以(yi)排除先導系統(tong)出現(xian)(xian)故(gu)障(zhang)的(de)(de)(de)(de)可能性。于(yu)是，驗證電子(zi)控制(zhi)(zhi)系統(tong)是否出現(xian)(xian)故(gu)障(zhang)。此故(gu)障(zhang)的(de)(de)(de)(de)判斷(duan)方法比(bi)較(jiao)簡單，因(yin)為(wei)(wei)系統(tong)上(shang)設置(zhi)有手動備用開(kai)關，當主(zhu)控制(zhi)(zhi)器(qi)(qi)(qi)(qi)或監控器(qi)(qi)(qi)(qi)出現(xian)(xian)問題時(shi)，將備用開(kai)關扳至手動位置(zhi)，可使機(ji)器(qi)(qi)(qi)(qi)繼續工(gong)作(zuo)。按上(shang)述方法操作(zuo)機(ji)器(qi)(qi)(qi)(qi)，結(jie)果動作(zuo)依然緩慢。故(gu)可初步認為(wei)(wei)主(zhu)控制(zhi)(zhi)器(qi)(qi)(qi)(qi)正(zheng)常(chang)；后(hou)又將開(kai)關反扳回自動位置(zhi)，再檢(jian)驗主(zhu)控制(zhi)(zhi)器(qi)(qi)(qi)(qi)上(shang)的(de)(de)(de)(de)3個(ge)發(fa)光二(er)(er)極管，見3個(ge)二(er)(er)極管均為(wei)(wei)綠光，再次證明(ming)主(zhu)控制(zhi)(zhi)器(qi)(qi)(qi)(qi)以(yi)及主(zhu)控制(zhi)(zhi)器(qi)(qi)(qi)(qi)與監控器(qi)(qi)(qi)(qi)之間的(de)(de)(de)(de)通(tong)(tong)信(xin)線路正(zheng)常(chang)。卡特彼勒(le)公司(si)的(de)(de)(de)(de)挖掘機(ji)上(shang)監控系統(tong)有很(hen)強的(de)(de)(de)(de)自檢(jian)及數據記憶功能，因(yin)此，我們可以(yi)通(tong)(tong)過監控器(qi)(qi)(qi)(qi)了解其他電子(zi)元(yuan)件的(de)(de)(de)(de)狀(zhuang)態和數據，從而(er)判斷(duan)它們工(gong)作(zuo)是否正(zheng)常(chang)。從監控器(qi)(qi)(qi)(qi)上(shang)輸入密(mi)碼后(hou)。
進(jin)入卡(ka)特彼(bi)勒的(de)(de)維修(xiu)模式，先檢(jian)(jian)(jian)查稆種(zhong)開關的(de)(de)狀(zhuang)態，結果表(biao)明各種(zhong)開關均處于(yu)(yu)正常狀(zhuang)態位置；然后檢(jian)(jian)(jian)查發(fa)動機額定(ding)轉速(su)以(yi)及泵(beng)在主(zhu)安全閥(fa)(fa)泄流時的(de)(de)壓(ya)(ya)(ya)(ya)(ya)力(li)，監控(kong)(kong)器顯(xian)示(shi)這項數據(ju)為1800r/min和(he)34.3MPa，均為正常值(zhi)；檢(jian)(jian)(jian)查比(bi)(bi)例減(jian)速(su)壓(ya)(ya)(ya)(ya)(ya)閥(fa)(fa)的(de)(de)壓(ya)(ya)(ya)(ya)(ya)力(li)變化范圍(wei)，在正常的(de)(de)操作(zuo)過(guo)程中，監控(kong)(kong)器顯(xian)示(shi)比(bi)(bi)便(bian)減(jian)壓(ya)(ya)(ya)(ya)(ya)閥(fa)(fa)的(de)(de)壓(ya)(ya)(ya)(ya)(ya)力(li)變化范圍(wei)為3.2~0.76MPa，即比(bi)(bi)例減(jian)壓(ya)(ya)(ya)(ya)(ya)閥(fa)(fa)的(de)(de)壓(ya)(ya)(ya)(ya)(ya)力(li)變化正常。再(zai)查盾現實故(gu)(gu)障(zhang)(zhang)(zhang)代(dai)碼(ma)和(he)以(yi)前記錄的(de)(de)故(gu)(gu)障(zhang)(zhang)(zhang)代(dai)碼(ma)，監控(kong)(kong)器均未顯(xian)示(shi)何(he)故(gu)(gu)障(zhang)(zhang)(zhang)代(dai)碼(ma)，至此可(ke)以(yi)肯(ken)定(ding)，問題(ti)不(bu)是出(chu)在電子控(kong)(kong)制(zhi)系統。最后，檢(jian)(jian)(jian)查液(ye)壓(ya)(ya)(ya)(ya)(ya)泵(beng)自身調(diao)節(jie)系統。其上、下泵(beng)的(de)(de)調(diao)節(jie)器是分開的(de)(de)，通過(guo)對左、右單邊行走的(de)(de)測(ce)試表(biao)時均存在問題(ti)，由于(yu)(yu)兩泵(beng)調(diao)節(jie)器均出(chu)現故(gu)(gu)障(zhang)(zhang)(zhang)的(de)(de)可(ke)能性較小，我(wo)們先將(jiang)其放在一邊。
從外(wai)(wai)部(bu)著看查(cha)起。液壓(ya)(ya)泵(beng)(beng)調節器(qi)的(de)(de)外(wai)(wai)部(bu)控(kong)(kong)制(zhi)信號有兩個(ge)：一(yi)個(ge)取自主(zhu)(zhu)(zhu)控(kong)(kong)閥(fa)(fa)中(zhong)心油道(dao)的(de)(de)壓(ya)(ya)力(li)(li)PN，上(shang)(shang)、下(xia)(xia)泵(beng)(beng)各(ge)一(yi)；另(ling)一(yi)個(ge)是(shi)來自同時(shi)控(kong)(kong)制(zhi)上(shang)(shang)、下(xia)(xia)泵(beng)(beng)的(de)(de)比(bi)例減(jian)壓(ya)(ya)閥(fa)(fa)的(de)(de)壓(ya)(ya)力(li)(li)PS。先(xian)分別測量上(shang)(shang)、下(xia)(xia)泵(beng)(beng)的(de)(de)壓(ya)(ya)力(li)(li)PN值(zhi)，得到當主(zhu)(zhu)(zhu)控(kong)(kong)閥(fa)(fa)中(zhong)位(wei)時(shi)壓(ya)(ya)力(li)(li)為(wei)4.07MPa，無論有任(ren)何(he)一(yi)下(xia)(xia)動作，PN即下(xia)(xia)降為(wei)0.35MPa，PN值(zhi)正(zheng)常(chang)。再測量PS值(zhi)，雖(sui)然(ran)已經通過(guo)監(jian)控(kong)(kong)器(qi)已查(cha)看到了PS值(zhi)的(de)(de)變化范圍，且其(qi)壓(ya)(ya)力(li)(li)變化值(zhi)正(zheng)常(chang)，但這(zhe)并(bing)不(bu)一(yi)定準確，因為(wei)比(bi)例減(jian)壓(ya)(ya)閥(fa)(fa)上(shang)(shang)并(bing)沒(mei)有壓(ya)(ya)力(li)(li)傳感器(qi)直接(jie)給主(zhu)(zhu)(zhu)控(kong)(kong)制(zhi)器(qi)經信號輸入，監(jian)控(kong)(kong)器(qi)顯示的(de)(de)壓(ya)(ya)力(li)(li)值(zhi)是(shi)主(zhu)(zhu)(zhu)控(kong)(kong)制(zhi)器(qi)通過(guo)對比(bi)例減(jian)壓(ya)(ya)閥(fa)(fa)的(de)(de)輸出電(dian)流信號經分析轉換而成(cheng)的(de)(de)、也就是(shi)說，此(ci)壓(ya)(ya)力(li)(li)值(zhi)對應主(zhu)(zhu)(zhu)控(kong)(kong)制(zhi)器(qi)對比(bi)例減(jian)壓(ya)(ya)閥(fa)(fa)輸出電(dian)流的(de)(de)強弱。為(wei)此(ci)，在泵(beng)(beng)體上(shang)(shang)的(de)(de)PS壓(ya)(ya)力(li)(li)側點接(jie)上(shang)(shang)壓(ya)(ya)力(li)(li)表。
