預應力軋機的(de)(de)原(yuan)理(li)及(ji)特點： 采用(yong)預(yu)(yu)(yu)應(ying)(ying)力(li)(li)(li)的(de)(de)方法(fa)可減(jian)少軋(ya)(ya)(ya)機(ji)(ji)(ji)(ji)(ji)彈(dan)跳變(bian)(bian)(bian)形(xing),預(yu)(yu)(yu)應(ying)(ying)力(li)(li)(li)軋(ya)(ya)(ya)機(ji)(ji)(ji)(ji)(ji)也(ye)是一(yi)種高剛(gang)(gang)度(du)軋(ya)(ya)(ya)機(ji)(ji)(ji)(ji)(ji)。它的(de)(de)基本原(yuan)理(li)是：利用(yong)受(shou)壓(ya)(ya)(ya)(ya)零件在(zai)(zai)軋(ya)(ya)(ya)制(zhi)(zhi)(zhi)前(qian)對(dui)機(ji)(ji)(ji)(ji)(ji)架(jia)(jia)(jia)(jia)施加預(yu)(yu)(yu)應(ying)(ying)力(li)(li)(li)，使其(qi)(qi)處于受(shou)力(li)(li)(li)狀(zhuang)態。這樣(yang)在(zai)(zai)軋(ya)(ya)(ya)制(zhi)(zhi)(zhi)時，由(you)(you)于預(yu)(yu)(yu)應(ying)(ying)力(li)(li)(li)的(de)(de)作(zuo)(zuo)(zuo)用(yong)，機(ji)(ji)(ji)(ji)(ji)架(jia)(jia)(jia)(jia)的(de)(de)彈(dan)性變(bian)(bian)(bian)形(xing)變(bian)(bian)(bian)化(hua)減(jian)小，從(cong)而提高了(le)軋(ya)(ya)(ya)機(ji)(ji)(ji)(ji)(ji)的(de)(de)剛(gang)(gang)度(du)。預(yu)(yu)(yu)應(ying)(ying)力(li)(li)(li)軋(ya)(ya)(ya)機(ji)(ji)(ji)(ji)(ji)在(zai)(zai)機(ji)(ji)(ji)(ji)(ji)架(jia)(jia)(jia)(jia)的(de)(de)橫(heng)梁(liang)與(yu)(yu)下(xia)支撐輥(gun)軸(zhou)承(cheng)座(zuo)之(zhi)(zhi)(zhi)間增設預(yu)(yu)(yu)應(ying)(ying)力(li)(li)(li)拉(la)桿，以(yi)及(ji)在(zai)(zai)下(xia)橫(heng)梁(liang)與(yu)(yu)下(xia)軸(zhou)承(cheng)座(zuo)之(zhi)(zhi)(zhi)間裝設預(yu)(yu)(yu)應(ying)(ying)力(li)(li)(li)加載液壓(ya)(ya)(ya)(ya)缸。軋(ya)(ya)(ya)制(zhi)(zhi)(zhi)前(qian)，液壓(ya)(ya)(ya)(ya)缸 對(dui)機(ji)(ji)(ji)(ji)(ji)座(zuo)進行預(yu)(yu)(yu)應(ying)(ying)力(li)(li)(li)加載，此時機(ji)(ji)(ji)(ji)(ji)架(jia)(jia)(jia)(jia)受(shou)拉(la)力(li)(li)(li)，而下(xia)軸(zhou)承(cheng)座(zuo)7和(he)壓(ya)(ya)(ya)(ya)桿 則(ze)受(shou)壓(ya)(ya)(ya)(ya)力(li)(li)(li)，其(qi)(qi)大(da)小都等于預(yu)(yu)(yu)緊(jin)力(li)(li)(li)(通(tong)常(chang)預(yu)(yu)(yu)緊(jin)力(li)(li)(li)要(yao)大(da)于1.5 倍的(de)(de)軋(ya)(ya)(ya)制(zhi)(zhi)(zhi)力(li)(li)(li)。 在(zai)(zai)預(yu)(yu)(yu)緊(jin)力(li)(li)(li)，機(ji)(ji)(ji)(ji)(ji)架(jia)(jia)(jia)(jia)產生(sheng)(sheng)拉(la)伸變(bian)(bian)(bian)形(xing)l1件產生(sheng)(sheng)壓(ya)(ya)(ya)(ya)縮變(bian)(bian)(bian)形(xing) 。直線AB 表示機(ji)(ji)(ji)(ji)(ji)架(jia)(jia)(jia)(jia)受(shou)力(li)(li)(li)與(yu)(yu)變(bian)(bian)(bian)形(xing)的(de)(de)關系(xi)，直線CD 則(ze)表示受(shou)壓(ya)(ya)(ya)(ya)零件的(de)(de)受(shou)力(li)(li)(li)與(yu)(yu)變(bian)(bian)(bian)形(xing)的(de)(de)關系(xi)。 軋(ya)(ya)(ya)制(zhi)(zhi)(zhi)時， 在(zai)(zai)軋(ya)(ya)(ya)制(zhi)(zhi)(zhi)力(li)(li)(li)P 的(de)(de)作(zuo)(zuo)(zuo)用(yong)下(xia)，機(ji)(ji)(ji)(ji)(ji)架(jia)(jia)(jia)(jia)上的(de)(de)作(zuo)(zuo)(zuo)用(yong)力(li)(li)(li)由(you)(you)0P 變(bian)(bian)(bian)為1P ，變(bian)(bian)(bian)形(xing)由(you)(you)1l 變(bian)(bian)(bian)為'1l，增加了(le)一(yi)個δ 。受(shou)壓(ya)(ya)(ya)(ya)件的(de)(de)作(zuo)(zuo)(zuo)用(yong)力(li)(li)(li)由(you)(you)0P變(bian)(bian)(bian)為2P ，變(bian)(bian)(bian)形(xing)由(you)(you)2l 變(bian)(bian)(bian)為'2l ，減(jian)少了(le)一(yi)個δ 。所以(yi)，由(you)(you)軋(ya)(ya)(ya)制(zhi)(zhi)(zhi)力(li)(li)(li)P 引起的(de)(de)軋(ya)(ya)(ya)機(ji)(ji)(ji)(ji)(ji)的(de)(de)彈(dan)性變(bian)(bian)(bian)形(xing)δ 12PKKδ=+    此時，預(yu)(yu)(yu)應(ying)(ying)力(li)(li)(li)軋(ya)(ya)(ya)機(ji)(ji)(ji)(ji)(ji)的(de)(de)剛(gang)(gang)度(du)系(xi)數為K = K1 + K2 。對(dui)于一(yi)般(ban)軋(ya)(ya)(ya)機(ji)(ji)(ji)(ji)(ji)，在(zai)(zai)軋(ya)(ya)(ya)制(zhi)(zhi)(zhi)力(li)(li)(li)P 作(zuo)(zuo)(zuo)用(yong)下(xia)，機(ji)(ji)(ji)(ji)(ji)架(jia)(jia)(jia)(jia)和(he)受(shou)壓(ya)(ya)(ya)(ya)件的(de)(de)彈(dan)性變(bian)(bian)(bian)形(xing)之(zhi)(zhi)(zhi)和(he)即為軋(ya)(ya)(ya)機(ji)(ji)(ji)(ji)(ji)的(de)(de)彈(dan)性變(bian)(bian)(bian)形(xing) 故一(yi)般(ban)軋(ya)(ya)(ya)機(ji)(ji)(ji)(ji)(ji)的(de)(de)剛(gang)(gang)度(du)系(xi)數可見(jian)，預(yu)(yu)(yu)應(ying)(ying)力(li)(li)(li)軋(ya)(ya)(ya)機(ji)(ji)(ji)(ji)(ji)的(de)(de)剛(gang)(gang)度(du)系(xi)數要(yao)比(bi)普通(tong)軋(ya)(ya)(ya)機(ji)(ji)(ji)(ji)(ji)的(de)(de)剛(gang)(gang)度(du)系(xi)數大(da)。但是預(yu)(yu)(yu)應(ying)(ying)力(li)(li)(li)軋(ya)(ya)(ya)機(ji)(ji)(ji)(ji)(ji)采用(yong)液壓(ya)(ya)(ya)(ya)螺母和(he)壓(ya)(ya)(ya)(ya)桿，使軋(ya)(ya)(ya)機(ji)(ji)(ji)(ji)(ji)結(jie)構變(bian)(bian)(bian)的(de)(de)復雜，加工(gong)精度(du)要(yao)求提高，尤(you)其(qi)(qi)對(dui)壓(ya)(ya)(ya)(ya)桿的(de)(de)制(zhi)(zhi)(zhi)造質量要(yao)求較高，為了(le)施加預(yu)(yu)(yu)應(ying)(ying)力(li)(li)(li)，還(huan)需(xu)備有高壓(ya)(ya)(ya)(ya)油泵(beng)和(he)一(yi)套油壓(ya)(ya)(ya)(ya)系(xi)統。當換輥(gun)或改(gai)變(bian)(bian)(bian)軋(ya)(ya)(ya)輥(gun)直徑時，需(xu)要(yao)換上軋(ya)(ya)(ya)輥(gun)軸(zhou)承(cheng)座(zuo)與(yu)(yu)半(ban)機(ji)(ji)(ji)(ji)(ji)架(jia)(jia)(jia)(jia)之(zhi)(zhi)(zhi)間的(de)(de)調(diao)(diao)整墊片，而且預(yu)(yu)(yu)應(ying)(ying)力(li)(li)(li)軋(ya)(ya)(ya)機(ji)(ji)(ji)(ji)(ji)不能實現對(dui)稱調(diao)(diao)整。