熟女俱乐部五十路六十路av_精品国产福利在线观看_国产香蕉视频在线播放_女人高潮特级毛片

拉彎(wan)就是把金屬板材(cai)(cai)、管(guan)(guan)材(cai)(cai)和型材(cai)(cai)彎(wan)曲成(cheng)一定(ding)曲率、形狀和尺寸(cun)的(de)工件的(de)沖壓成(cheng)形工藝(yi)。 拉彎(wan)成(cheng)形廣泛應(ying)用于制造高壓容器、鍋爐(lu)汽包、鍋爐(lu)爐(lu)管(guan)(guan)、船體(ti)的(de)鋼板及骨肋、各種器皿、儀器儀表構件以及箱柜鑲(xiang)條等。

    拉(la)彎(wan)根據工藝特點(dian)，可將(jiang)拉(la)彎(wan)分(fen)為頂彎(wan)、壓(ya)(ya)(ya)(ya)彎(wan)、以及滾彎(wan)， 壓(ya)(ya)(ya)(ya)彎(wan)是(shi)常用(yong)的(de)(de)(de)彎(wan)曲(qu)方(fang)法。所(suo)用(yong)設備大多為通用(yong)的(de)(de)(de)機(ji)(ji)(ji)械壓(ya)(ya)(ya)(ya)力機(ji)(ji)(ji)或液壓(ya)(ya)(ya)(ya)機(ji)(ji)(ji)，也有(you)用(yong)專用(yong)折(zhe)彎(wan)壓(ya)(ya)(ya)(ya)力機(ji)(ji)(ji)的(de)(de)(de)。常用(yong)的(de)(de)(de)滾彎(wan)設備是(shi)卷(juan)(juan)板(ban)(ban)機(ji)(ji)(ji)。三(san)(san)輥(gun)(gun)卷(juan)(juan)板(ban)(ban)機(ji)(ji)(ji)按三(san)(san)點(dian)決定一(yi)圓(yuan)的(de)(de)(de)道理，對(dui)板(ban)(ban)坯(pi)進行連續彎(wan)曲(qu)。三(san)(san)輥(gun)(gun)卷(juan)(juan)板(ban)(ban)機(ji)(ji)(ji)具有(you)兩個(ge)傳動(dong)(dong)(dong)(dong)輥(gun)(gun)（固定）和(he)一(yi)個(ge)壓(ya)(ya)(ya)(ya)下(xia)輥(gun)(gun)（可調(diao)）。調(diao)節壓(ya)(ya)(ya)(ya)下(xia)輥(gun)(gun)的(de)(de)(de)上(shang)下(xia)位置即可改變它與(yu)傳動(dong)(dong)(dong)(dong)輥(gun)(gun)之(zhi)(zhi)間的(de)(de)(de)相對(dui)距離(li)。拉(la)彎(wan)時，板(ban)(ban)材置于(yu)傳動(dong)(dong)(dong)(dong)輥(gun)(gun)和(he)壓(ya)(ya)(ya)(ya)下(xia)輥(gun)(gun)之(zhi)(zhi)間，傳動(dong)(dong)(dong)(dong)輥(gun)(gun)正反方(fang)向交換(huan)轉動(dong)(dong)(dong)(dong)，使(shi)板(ban)(ban)材往復運動(dong)(dong)(dong)(dong)。調(diao)節壓(ya)(ya)(ya)(ya)下(xia)輥(gun)(gun)使(shi)之(zhi)(zhi)逐步(bu)壓(ya)(ya)(ya)(ya)下(xia)，即可將(jiang)板(ban)(ban)材彎(wan)曲(qu)成所(suo)需曲(qu)率的(de)(de)(de)圓(yuan)柱面(mian)、圓(yuan)錐(zhui)面(mian)和(he)曲(qu)率較小的(de)(de)(de)雙曲(qu)面(mian)。壓(ya)(ya)(ya)(ya)下(xia)輥(gun)(gun)一(yi)端可升起，便于(yu)卸(xie)出(chu)工件。另外還有(you)四(si)輥(gun)(gun)和(he)多輥(gun)(gun)卷(juan)(juan)板(ban)(ban)機(ji)(ji)(ji)，四(si)輥(gun)(gun)卷(juan)(juan)板(ban)(ban)機(ji)(ji)(ji)用(yong)于(yu)卷(juan)(juan)制厚板(ban)(ban)圓(yuan)筒，四(si)輥(gun)(gun)以上(shang)的(de)(de)(de)多輥(gun)(gun)卷(juan)(juan)板(ban)(ban)機(ji)(ji)(ji)，用(yong)多對(dui)輥(gun)(gun)子將(jiang)板(ban)(ban)材逐漸彎(wan)曲(qu)成復雜的(de)(de)(de)型面(mian)。        

    對于精度(du)要求較(jiao)高，長度(du)和(he)曲率半徑要求較(jiao)大、橫(heng)向尺寸要求較(jiao)小(xiao)的彎(wan)曲件，可在專用的拉彎(wan)機上(shang)進(jin)行拉彎(wan)。拉彎(wan)時，板材(cai)全部厚度(du)上(shang)都受拉應力的作用，因而只(zhi)產(chan)生伸(shen)長變形，卸載后彈(dan)復(fu)引(yin)起的變形小(xiao)，容易(yi)保證精度(du)。