SMC電氣比例閥的結構原理：
輸入信號增大，供(gong)(gong)(gong)氣(qi)(qi)用電磁閥(fa)(fa)先導(dao)閥(fa)(fa)1換向，而排氣(qi)(qi)用電磁先導(dao)閥(fa)(fa)7處于復位狀態，則供(gong)(gong)(gong)氣(qi)(qi)壓(ya)(ya)力(li)(li)從(cong)SUP口通過閥(fa)(fa)1進(jin)(jin)入先導(dao)室5，先導(dao)室壓(ya)(ya)力(li)(li)上(shang)升，氣(qi)(qi)壓(ya)(ya)力(li)(li)作(zuo)用在膜片2的(de)(de)上(shang)方，則和膜片2相連的(de)(de)供(gong)(gong)(gong)氣(qi)(qi)閥(fa)(fa)芯(xin)4便開(kai)啟，排氣(qi)(qi)閥(fa)(fa)芯(xin)3關閉，產(chan)生輸出(chu)(chu)壓(ya)(ya)力(li)(li)。此輸出(chu)(chu)壓(ya)(ya)力(li)(li)通過壓(ya)(ya)力(li)(li)傳感器6反饋至控制回路8。在這里(li)，與(yu)目標(biao)值(zhi)進(jin)(jin)行快(kuai)速(su)比(bi)較修正(zheng)，直(zhi)到(dao)輸出(chu)(chu)壓(ya)(ya)力(li)(li)與(yu)輸入信號成(cheng)一(yi)定比(bi)例為止(zhi)，從(cong)而得到(dao)輸出(chu)(chu)壓(ya)(ya)力(li)(li)與(yu)輸入信號的(de)(de)變(bian)化成(cheng)比(bi)例的(de)(de)變(bian)化。由于沒(mei)有噴(pen)嘴擋板機構，故閥(fa)(fa)對雜質不(bu)敏感，可靠(kao)性高。

SMC電(dian)(dian)(dian)(dian)氣比(bi)例(li)(li)閥(fa)的(de)(de)(de)(de)(de)維(wei)修(xiu)方法(fa)(fa)(fa)：在(zai)(zai)(zai)(zai)實(shi)際(ji)的(de)(de)(de)(de)(de)維(wei)修(xiu)過(guo)程(cheng)(cheng)中，對(dui)(dui)存(cun)(cun)在(zai)(zai)(zai)(zai)問(wen)(wen)題(ti)的(de)(de)(de)(de)(de)零(ling)部(bu)件(jian)可(ke)以(yi)采取直(zhi)接(jie)更(geng)(geng)(geng)(geng)換(huan)的(de)(de)(de)(de)(de)方法(fa)(fa)(fa)，同時還(huan)要(yao)對(dui)(dui)該閥(fa)的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)氣零(ling)點(dian)和死區(qu)進行調(diao)節，如(ru)果有實(shi)驗條件(jian)還(huan)要(yao)對(dui)(dui)維(wei)修(xiu)后閥(fa)的(de)(de)(de)(de)(de)行程(cheng)(cheng)進行驗證。（1)更(geng)(geng)(geng)(geng)換(huan)存(cun)(cun)在(zai)(zai)(zai)(zai)問(wen)(wen)題(ti)的(de)(de)(de)(de)(de)零(ling)部(bu)件(jian)更(geng)(geng)(geng)(geng)換(huan)法(fa)(fa)(fa)是(shi)對(dui)(dui)存(cun)(cun)在(zai)(zai)(zai)(zai)問(wen)(wen)題(ti)的(de)(de)(de)(de)(de)零(ling)部(bu)件(jian)進行整(zheng)體或者(zhe)部(bu)分更(geng)(geng)(geng)(geng)換(huan)。更(geng)(geng)(geng)(geng)換(huan)法(fa)(fa)(fa)在(zai)(zai)(zai)(zai)工(gong)程(cheng)(cheng)機械閥(fa)的(de)(de)(de)(de)(de)維(wei)修(xiu)中應用(yong)(yong)相(xiang)(xiang)當廣泛，該方法(fa)(fa)(fa)的(de)(de)(de)(de)(de)關(guan)鍵是(shi)查找出現(xian)問(wen)(wen)題(ti)的(de)(de)(de)(de)(de)部(bu)件(jian)，找到(dao)問(wen)(wen)題(ti)后就可(ke)以(yi)更(geng)(geng)(geng)(geng)換(huan)一(yi)個(ge)與之相(xiang)(xiang)同的(de)(de)(de)(de)(de)完(wan)好部(bu)件(jian)，一(yi)般(ban)情況下(xia)通過(guo)這種維(wei)修(xiu)方法(fa)(fa)(fa)就能使(shi)閥(fa)實(shi)現(xian)正常(chang)工(gong)作。導(dao)致比(bi)例(li)(li)閥(fa)失效比(bi)較普(pu)遍(bian)的(de)(de)(de)(de)(de)原因是(shi)閥(fa)的(de)(de)(de)(de)(de)密封件(jian)過(guo)度磨損(sun)、閥(fa)芯(xin)(xin)(xin)位(wei)移(yi)傳感(gan)器(qi)探針折(zhe)斷，而集成放大(da)器(qi)一(yi)般(ban)不會出現(xian)問(wen)(wen)題(ti)。（2)電(dian)(dian)(dian)(dian)氣零(ling)點(dian)的(de)(de)(de)(de)(de)調(diao)節在(zai)(zai)(zai)(zai)工(gong)程(cheng)(cheng)機械中，比(bi)例(li)(li)閥(fa)一(yi)直(zhi)工(gong)作在(zai)(zai)(zai)(zai)惡劣的(de)(de)(de)(de)(de)環境下(xia)，而其電(dian)(dian)(dian)(dian)氣零(ling)點(dian)易受(shou)到(dao)外(wai)界環境的(de)(de)(de)(de)(de)干擾，ATOS比(bi)例(li)(li)閥(fa)因此在(zai)(zai)(zai)(zai)更(geng)(geng)(geng)(geng)換(huan)了失效的(de)(de)(de)(de)(de)零(ling)部(bu)件(jian)后就應當對(dui)(dui)其電(dian)(dian)(dian)(dian)氣零(ling)點(dian)進行檢測，對(dui)(dui)不符合要(yao)求的(de)(de)(de)(de)(de)應重新標定。一(yi)般(ban)檢測方法(fa)(fa)(fa)如(ru)下(xia):給比(bi)例(li)(li)閥(fa)的(de)(de)(de)(de)(de)放大(da)器(qi)供電(dian)(dian)(dian)(dian)(一(yi)般(ban)情況下(xia)0一(yi)24 V)，ATOS比(bi)例(li)(li)閥(fa)確保閥(fa)芯(xin)(xin)(xin)處于斷電(dian)(dian)(dian)(dian)狀態，用(yong)(yong)萬用(yong)(yong)電(dian)(dian)(dian)(dian)表(直(zhi)流擋，0.25 V量程(cheng)(cheng))檢測閥(fa)芯(xin)(xin)(xin)位(wei)移(yi)反(fan)(fan)饋(kui)信號，在(zai)(zai)(zai)(zai)閥(fa)芯(xin)(xin)(xin)沒有接(jie)受(shou)指令的(de)(de)(de)(de)(de)條件(jian)下(xia)，要(yao)求閥(fa)芯(xin)(xin)(xin)位(wei)移(yi)反(fan)(fan)饋(kui)電(dian)(dian)(dian)(dian)壓(ya)為(wei)零(ling)。如(ru)果不為(wei)零(ling)就應調(diao)節閥(fa)芯(xin)(xin)(xin)位(wei)移(yi)傳感(gan)器(qi)的(de)(de)(de)(de)(de)調(diao)節螺母，直(zhi)至閥(fa)芯(xin)(xin)(xin)反(fan)(fan)饋(kui)電(dian)(dian)(dian)(dian)壓(ya)為(wei)零(ling)。