数控机床对进给传动机构的要求
数控(kong)(kong)(kong)机(ji)床(chuang)的(de)(de)(de)(de)(de)进(jin)(jin)给传(chuan)(chuan)(chuan)动(dong)(dong)系(xi)(xi)统(tong)(tong)(tong)常用伺服(fu)(fu)进(jin)(jin)给系(xi)(xi)统(tong)(tong)(tong)来工作(zuo)。伺服(fu)(fu)进(jin)(jin)给系(xi)(xi)统(tong)(tong)(tong)的(de)(de)(de)(de)(de)作(zuo)用是(shi)根据数控(kong)(kong)(kong)系(xi)(xi)统(tong)(tong)(tong)传(chuan)(chuan)(chuan)来的(de)(de)(de)(de)(de)指令(ling)消息，进(jin)(jin)行放大(da)(da)以后控(kong)(kong)(kong)制(zhi)执行部(bu)件(jian)(jian)的(de)(de)(de)(de)(de)运(yun)动(dong)(dong)，不仅控(kong)(kong)(kong)制(zhi)进(jin)(jin)给运(yun)动(dong)(dong)的(de)(de)(de)(de)(de)速度(du)，而(er)且还要精确控(kong)(kong)(kong)制(zhi)刀(dao)具(ju)相对于工件(jian)(jian)的(de)(de)(de)(de)(de)移动(dong)(dong)位置和轨迹。一个典型的(de)(de)(de)(de)(de)数控(kong)(kong)(kong)机(ji)床(chuang)闭环控(kong)(kong)(kong)制(zhi)的(de)(de)(de)(de)(de)进(jin)(jin)给系(xi)(xi)统(tong)(tong)(tong)，通(tong)常由位置比较，放大(da)(da)部(bu)件(jian)(jian)，驱动(dong)(dong)单元，机(ji)械进(jin)(jin)给传(chuan)(chuan)(chuan)动(dong)(dong)机(ji)构(gou)和检测(ce)反馈元件(jian)(jian)等几部(bu)分组成。其中，数控(kong)(kong)(kong)机(ji)床(chuang)的(de)(de)(de)(de)(de)机(ji)械进(jin)(jin)给传(chuan)(chuan)(chuan)动(dong)(dong)机(ji)构(gou)是(shi)指将伺服(fu)(fu)电动(dong)(dong)机(ji)的(de)(de)(de)(de)(de)旋转运(yun)动(dong)(dong)变为工作(zuo)台(tai)或刀(dao)架直线(xian)进(jin)(jin)给运(yun)动(dong)(dong)的(de)(de)(de)(de)(de)整个机(ji)械传(chuan)(chuan)(chuan)动(dong)(dong)链(lian)，主要包括(kuo)减速装置，丝杆螺母副，导向部(bu)件(jian)(jian)及其支承件(jian)(jian)等。数控(kong)(kong)(kong)机(ji)床(chuang)进(jin)(jin)给机(ji)构(gou)是(shi)伺服(fu)(fu)系(xi)(xi)统(tong)(tong)(tong)中的(de)(de)(de)(de)(de)一个重要环节，除了具(ju)有较高的(de)(de)(de)(de)(de)定(ding)位精度(du)之外(wai)，还应具(ju)有良好(hao)的(de)(de)(de)(de)(de)动(dong)(dong)态响应特性，系(xi)(xi)统(tong)(tong)(tong)跟踪指令(ling)信号(hao)的(de)(de)(de)(de)(de)响应要快，稳定(ding)性要好(hao)。
为确保数控机(ji)床进(jin)(jin)给(ji)系统的传动(dong)精度，系统的稳定(ding)性和(he)动(dong)态响应特性，对进(jin)(jin)给(ji)机(ji)构提出了无间(jian)隙，低摩擦，低惯(guan)量，高刚(gang)度，高谐振率(lv)以及有适宜阻尼比等要求。为达到这些要求，主要采取如下措施：
尽量采用低(di)摩擦的(de)传动，如(ru)采用静压导轨，滚动导轨和滚珠丝杆等，以(yi)减少摩擦力(li)。
采用最佳的传动比，以(yi)提(ti)高机床分辨率，使工(gong)作台(tai)尽(jin)可能大地加速，以(yi)达到跟踪指令，使系统折算到驱动轴上(shang)的传动惯(guan)量尽(jin)量小。
缩短传(chuan)动(dong)链(lian)以(yi)及用(yong)预(yu)紧的(de)(de)办法(fa)提高传(chuan)动(dong)系统的(de)(de)刚度，如采用(yong)电动(dong)机(ji)直接驱动(dong)丝杆(gan)，应有预(yu)加负载的(de)(de)滚动(dong)导轨和(he)滚动(dong)丝杆(gan)副，丝杆(gan)支(zhi)承设(she)计成(cheng)两端向固定(ding)的(de)(de)，并可用(yong)预(yu)拉伸(shen)的(de)(de)结构(gou)等办法(fa)来提高传(chuan)动(dong)系统的(de)(de)刚度。
尽量消(xiao)除(chu)传动间隙，减少反向死区误(wu)差(cha)，如采用消(xiao)除(chu)间隙的联轴器，采用有(you)消(xiao)除(chu)间隙措(cuo)施的传动副等。
