直(zhi)線導軌又稱線軌、滑(hua)軌、線性導軌、線性滑(hua)軌，用(yong)于高(gao)精(jing)或(huo)高(gao)速直(zhi)線往復運(yun)動(dong)場合，且可以承(cheng)擔一定(ding)的扭矩，可在高(gao)負載的情況(kuang)下實現高(gao)精(jing)度的直(zhi)線運(yun)動(dong)。

直線(xian)(xian)(xian)導(dao)軌(gui)(gui)運(yun)動(dong)(dong)(dong)的作用是用來支撐和(he)引導(dao)運(yun)動(dong)(dong)(dong)部(bu)件(jian)，按給定(ding)的方(fang)向做往復直線(xian)(xian)(xian)運(yun)動(dong)(dong)(dong)。　直線(xian)(xian)(xian)軸承主要用在(zai)(zai)(zai)自動(dong)(dong)(dong)化機械上比較多(duo),像(xiang)直線(xian)(xian)(xian)導(dao)軌(gui)(gui)主要是用在(zai)(zai)(zai)精度要求比較高(gao)的機械結構(gou)上,直線(xian)(xian)(xian)導(dao)軌(gui)(gui)的移動(dong)(dong)(dong)元(yuan)(yuan)件(jian)和(he)固(gu)定(ding)元(yuan)(yuan)件(jian)之間(jian)不用中間(jian)介質，而用滾(gun)動(dong)(dong)(dong)鋼球。可以理解為是一種滾(gun)動(dong)(dong)(dong)導(dao)引，是由鋼珠在(zai)(zai)(zai)滑(hua)塊跟導(dao)軌(gui)(gui)之間(jian)無限滾(gun)動(dong)(dong)(dong)循環， 從而使負載平(ping)(ping)臺沿著導(dao)軌(gui)(gui)輕易的高(gao)精度線(xian)(xian)(xian)性(xing)(xing)運(yun)動(dong)(dong)(dong)，并將(jiang)摩擦系(xi)數降至(zhi)平(ping)(ping)常傳統滑(hua)動(dong)(dong)(dong)導(dao)引的五十分之一，能(neng)輕易地達到很高(gao)的定(ding)位精度。滑(hua)塊跟導(dao)軌(gui)(gui)間(jian)末制單(dan)元(yuan)(yuan)設(she)計，使線(xian)(xian)(xian)形導(dao)軌(gui)(gui)同時承受上下左(zuo)右等各方(fang)向的負荷，回流(liu)系(xi)統及精簡化的結構(gou)設(she)計讓線(xian)(xian)(xian)性(xing)(xing)導(dao)軌(gui)(gui)有更平(ping)(ping)順(shun)且低噪音(yin)的運(yun)動(dong)(dong)(dong)。

滑塊-使(shi)運動(dong)由曲線轉變為直線。

直(zhi)線導軌主要是(shi)用(yong)在精度要求比較高(gao)的機(ji)械(xie)(xie)結構上(shang),直(zhi)線導軌的移(yi)動(dong)元(yuan)件和固定元(yuan)件之間不用(yong)中間介質，而用(yong)滾動(dong)鋼(gang)球。因為滾動(dong)鋼(gang)球適應(ying)(ying)于高(gao)速運動(dong)、摩擦系數小、靈敏度高(gao)，滿足運動(dong)部件的工(gong)作要求，被(bei)廣(guang)泛應(ying)(ying)用(yong)在自動(dong)化機(ji)械(xie)(xie)上(shang)比較多,像磨床(chuang)、銑床(chuang)、車床(chuang)、檢測(ce)儀器設備、木工(gong)機(ji)械(xie)(xie)、搬運機(ji)械(xie)(xie)、傳送裝置、自動(dong)化機(ji)械(xie)(xie)、半導體機(ji)械(xie)(xie)、包裝機(ji)械(xie)(xie)、機(ji)械(xie)(xie)手臂、自動(dong)化機(ji)床(chuang)、激(ji)光行業(ye)、汽車制(zhi)造、新能(neng)源(yuan)等行業(ye)。