目前應用于數控外圓磨床的液壓傳動系統換向方法很多，對常用的液壓傳動系統換向方法進行分析，下面對其進行簡單的分析對比。行程換向閥的換向方法系統中的換向方法和換向控制參數對換向沖擊起著決定性的作用，外圓磨床采用液壓傳動系統。設計新的液壓換向系統迫在眉睫。以下從換向方法和控制策略的角度探討外圓磨床的換向沖擊。

換向(xiang)(xiang)閥(fa)(fa)芯上連接一個拔(ba)(ba)桿(gan)，采(cai)用(yong)(yong)行程(cheng)換向(xiang)(xiang)閥(fa)(fa)換向(xiang)(xiang)。利用(yong)(yong)工(gong)作(zuo)臺(tai)(tai)上的行程(cheng)擋塊推(tui)動(dong)(dong)(dong)(dong)拔(ba)(ba)桿(gan)實現(xian)自動(dong)(dong)(dong)(dong)換向(xiang)(xiang)。工(gong)作(zuo)臺(tai)(tai)慢速運動(dong)(dong)(dong)(dong)時(shi)，當(dang)(dang)換向(xiang)(xiang)閥(fa)(fa)到(dao)達(da)中間位置(zhi)時(shi)，無論液壓(ya)(ya)(ya)缸(gang)的左右兩腔(qiang)(qiang)是通過壓(ya)(ya)(ya)力(li)油的，還是通過回油的，或(huo)者都(dou)是關閉的。此時(shi)液壓(ya)(ya)(ya)缸(gang)的兩腔(qiang)(qiang)沒有液壓(ya)(ya)(ya)力(li)驅(qu)動(dong)(dong)(dong)(dong)，工(gong)作(zuo)臺(tai)(tai)的運動(dong)(dong)(dong)(dong)就會停止(zhi)，所以換向(xiang)(xiang)閥(fa)(fa)無法到(dao)達(da)另一端，所謂的死(si)點就出現(xian)了；金機通提示(shi)，當(dang)(dang)工(gong)作(zuo)臺(tai)(tai)高速運動(dong)(dong)(dong)(dong)時(shi)，擋塊推(tui)動(dong)(dong)(dong)(dong)拔(ba)(ba)桿(gan)，使(shi)換向(xiang)(xiang)閥(fa)(fa)的轉換方(fang)向(xiang)(xiang)非常快(kuai)，液壓(ya)(ya)(ya)缸(gang)的一腔(qiang)(qiang)壓(ya)(ya)(ya)力(li)突然從(cong)工(gong)作(zuo)壓(ya)(ya)(ya)力(li)p下降到(dao)0，另一腔(qiang)(qiang)從(cong)0突然上升到(dao)p，造成很大的換向(xiang)(xiang)沖擊。目前，該系統廣(guang)泛應用(yong)(yong)于小型外圓磨床。

行(xing)程(cheng)擋塊驅動行(xing)程(cheng)開關(guan)發出換(huan)向(xiang)(xiang)(xiang)(xiang)信號(hao)，行(xing)程(cheng)換(huan)向(xiang)(xiang)(xiang)(xiang)閥改為電磁換(huan)向(xiang)(xiang)(xiang)(xiang)閥。使電磁鐵動作推(tui)動滑(hua)閥換(huan)向(xiang)(xiang)(xiang)(xiang)，可以防止死(si)點，但(dan)它(ta)是一種(zhong)開關(guan)液(ye)(ye)壓閥，根據指令(ling)瞬間(jian)打(da)開或關(guan)閉，即瞬間(jian)打(da)開或切斷回油通(tong)道。這種(zhong)液(ye)(ye)壓換(huan)向(xiang)(xiang)(xiang)(xiang)系統在換(huan)向(xiang)(xiang)(xiang)(xiang)時會產(chan)生(sheng)很大的沖擊。采(cai)用電液(ye)(ye)換(huan)向(xiang)(xiang)(xiang)(xiang)閥的換(huan)向(xiang)(xiang)(xiang)(xiang)方(fang)法。

然后控制油(you)推動(dong)(dong)主(zhu)閥(fa)(fa)換(huan)(huan)(huan)(huan)向(xiang)(xiang)。在先導閥(fa)(fa)沒有換(huan)(huan)(huan)(huan)向(xiang)(xiang)之前，用電(dian)液(ye)(ye)(ye)換(huan)(huan)(huan)(huan)向(xiang)(xiang)閥(fa)(fa)代替(ti)電(dian)磁換(huan)(huan)(huan)(huan)向(xiang)(xiang)閥(fa)(fa)是一種新的換(huan)(huan)(huan)(huan)向(xiang)(xiang)方(fang)法。電(dian)液(ye)(ye)(ye)換(huan)(huan)(huan)(huan)向(xiang)(xiang)閥(fa)(fa)由先導閥(fa)(fa)電(dian)磁滑閥(fa)(fa)和主(zhu)閥(fa)(fa)液(ye)(ye)(ye)動(dong)(dong)滑閥(fa)(fa)組成。該系(xi)(xi)統(tong)(tong)通過(guo)先導閥(fa)(fa)換(huan)(huan)(huan)(huan)向(xiang)(xiang)切換(huan)(huan)(huan)(huan)控制油(you)路(lu)。控制油(you)路(lu)的油(you)流方(fang)向(xiang)(xiang)不變，換(huan)(huan)(huan)(huan)向(xiang)(xiang)閥(fa)(fa)始(shi)終保持在原來(lai)的一端，主(zhu)油(you)路(lu)方(fang)向(xiang)(xiang)不變，工作臺始(shi)終可(ke)以(yi)(yi)前進。配合理(li)想的控制曲(qu)線(xian)。外圓磨床采用電(dian)液(ye)(ye)(ye)比例閥(fa)(fa)的液(ye)(ye)(ye)壓(ya)傳(chuan)動(dong)(dong)系(xi)(xi)統(tong)(tong)換(huan)(huan)(huan)(huan)向(xiang)(xiang)系(xi)(xi)統(tong)(tong)。一種智能(neng)控制換(huan)(huan)(huan)(huan)向(xiang)(xiang)系(xi)(xi)統(tong)(tong)，可(ke)以(yi)(yi)通過(guo)主(zhu)動(dong)(dong)減少(shao)流量來(lai)降低速度，較終達到穩定無沖擊換(huan)(huan)(huan)(huan)向(xiang)(xiang)的目的。該液(ye)(ye)(ye)壓(ya)傳(chuan)動(dong)(dong)系(xi)(xi)統(tong)(tong)換(huan)(huan)(huan)(huan)向(xiang)(xiang)系(xi)(xi)統(tong)(tong)實現了良好的輸出位移或(huo)速度智能(neng)化。