A4VG系列(lie)變(bian)(bian)(bian)(bian)量柱(zhu)塞泵(beng)的(de)EP控(kong)(kong)制(zhi)采(cai)用(yong)比(bi)例閥直接控(kong)(kong)制(zhi)變(bian)(bian)(bian)(bian)量活塞，結構簡單，制(zhi)造成(cheng)本低，抗污染能力(li)強。其控(kong)(kong)制(zhi)電(dian)(dian)l流(liu)要(yao)求(qiu)大（即操(cao)作功率(lv)要(yao)求(qiu)大），最(zui)大流(liu)最(zui)所(suo)需．最(zui)大電(dian)(dian)流(liu)為(wei)600mA（24V電(dian)(dian)壓），響(xiang)應(ying)(ying)速度也(ye)較慢。當變(bian)(bian)(bian)(bian)量活塞上移(yi)時(shi)，帶(dai)動(dong)(dong)(dong)反(fan)饋(kui)桿繞固定轉(zhuan)(zhuan)軸(zhou)(zhou)轉(zhuan)(zhuan)動(dong)(dong)(dong)，通過(guo)(guo)反(fan)饋(kui)桿撥柱(zhu)帶(dai)動(dong)(dong)(dong)伺服(fu)平(ping)衡桿固定轉(zhuan)(zhuan)軸(zhou)(zhou)中心(xin)順(shun)時(shi)針(zhen)擺動(dong)(dong)(dong) ．拉動(dong)(dong)(dong)彈(dan)簧(huang)(huang)下(xia)行(xing)(xing)(xing)(xing)。因電(dian)(dian)磁(ci)力(li)fT。一定，彈(dan)簧(huang)(huang)下(xia)行(xing)(xing)(xing)(xing)時(shi)，彈(dan)簧(huang)(huang)力(li)不會增加，只能拉動(dong)(dong)(dong)伺服(fu)平(ping)衡桿和(he)伺服(fu)閥芯(xin)下(xia)行(xing)(xing)(xing)(xing)，當伺服(fu)閥芯(xin)下(xia)行(xing)(xing)(xing)(xing)到中位(wei)（即伺服(fu)閥芯(xin)下(xia)移(yi)z，此(ci)時(shi)變(bian)(bian)(bian)(bian)量活塞上行(xing)(xing)(xing)(xing)Y=X1b／c），變(bian)(bian)(bian)(bian)量活塞上下(xia)腔(qiang)進出(chu)油 口(kou)均關閉．變(bian)(bian)(bian)(bian)量活塞停(ting)止運動(dong)(dong)(dong) ，反(fan)饋(kui)桿撥柱(zhu)也(ye)停(ting)止轉(zhuan)(zhuan)動(dong)(dong)(dong)。這樣只要(yao)給定變(bian)(bian)(bian)(bian)量斜軸(zhou)(zhou)泵(beng)磁(ci)閥一個電(dian)(dian)流(liu)，（允(yun)許范圍內）．比(bi)例電(dian)(dian)磁(ci)鐵就產(chan)生相應(ying)(ying)的(de)電(dian)(dian)磁(ci)力(li) ，經(jing)過(guo)(guo) 以上一系列(lie)過(guo)(guo)程，使變(bian)(bian)(bian)(bian)量斜軸(zhou)(zhou)泵(beng)變(bian)(bian)(bian)(bian)量活塞位(wei)移(yi)相應(ying)(ying)量，即可對應(ying)(ying)一定排量的(de)輸出(chu)，實(shi)現電(dian)(dian)液比(bi)例控(kong)(kong)制(zhi)變(bian)(bian)(bian)(bian)量。