直線導軌又稱線軌、滑(hua)(hua)軌、線性導軌、線性滑(hua)(hua)軌，用于高(gao)精或高(gao)速直線往復(fu)運動(dong)場合，且可以承擔一定的(de)扭矩(ju)，可在高(gao)負載的(de)情況下實現(xian)高(gao)精度的(de)直線運動(dong)。

直線導(dao)(dao)(dao)軌(gui)(gui)運(yun)(yun)動(dong)(dong)(dong)的(de)(de)作(zuo)用(yong)(yong)是(shi)用(yong)(yong)來支撐和引(yin)導(dao)(dao)(dao)運(yun)(yun)動(dong)(dong)(dong)部件(jian)，按給定(ding)的(de)(de)方向(xiang)做(zuo)往復直線運(yun)(yun)動(dong)(dong)(dong)。　直線軸承(cheng)主(zhu)要用(yong)(yong)在(zai)自動(dong)(dong)(dong)化(hua)機械(xie)上(shang)比(bi)(bi)較多,像直線導(dao)(dao)(dao)軌(gui)(gui)主(zhu)要是(shi)用(yong)(yong)在(zai)精度要求比(bi)(bi)較高(gao)的(de)(de)機械(xie)結構上(shang),直線導(dao)(dao)(dao)軌(gui)(gui)的(de)(de)移動(dong)(dong)(dong)元件(jian)和固定(ding)元件(jian)之(zhi)間(jian)不用(yong)(yong)中(zhong)間(jian)介質，而(er)用(yong)(yong)滾動(dong)(dong)(dong)鋼球。可以(yi)理解為(wei)是(shi)一種滾動(dong)(dong)(dong)導(dao)(dao)(dao)引(yin)，是(shi)由鋼珠(zhu)在(zai)滑(hua)(hua)塊跟(gen)導(dao)(dao)(dao)軌(gui)(gui)之(zhi)間(jian)無限滾動(dong)(dong)(dong)循環， 從而(er)使(shi)負載平臺沿著導(dao)(dao)(dao)軌(gui)(gui)輕(qing)易(yi)的(de)(de)高(gao)精度線性(xing)運(yun)(yun)動(dong)(dong)(dong)，并將摩擦系(xi)數降至(zhi)平常傳統(tong)滑(hua)(hua)動(dong)(dong)(dong)導(dao)(dao)(dao)引(yin)的(de)(de)五(wu)十分之(zhi)一，能輕(qing)易(yi)地(di)達(da)到(dao)很高(gao)的(de)(de)定(ding)位精度。滑(hua)(hua)塊跟(gen)導(dao)(dao)(dao)軌(gui)(gui)間(jian)末制單元設(she)計，使(shi)線形導(dao)(dao)(dao)軌(gui)(gui)同時承(cheng)受上(shang)下左右等各方向(xiang)的(de)(de)負荷，回流系(xi)統(tong)及(ji)精簡化(hua)的(de)(de)結構設(she)計讓線性(xing)導(dao)(dao)(dao)軌(gui)(gui)有更平順(shun)且低噪(zao)音(yin)的(de)(de)運(yun)(yun)動(dong)(dong)(dong)。

滑塊-使運(yun)動(dong)由(you)曲線轉變為直線。

直(zhi)線導軌主要是用(yong)在(zai)精度要求(qiu)比較高(gao)的(de)機(ji)械結構上(shang)(shang),直(zhi)線導軌的(de)移動元件(jian)(jian)和固定元件(jian)(jian)之(zhi)間不用(yong)中間介質，而用(yong)滾(gun)動鋼球。因為(wei)滾(gun)動鋼球適應(ying)于(yu)高(gao)速(su)運(yun)(yun)動、摩擦系數小、靈敏度高(gao)，滿足(zu)運(yun)(yun)動部件(jian)(jian)的(de)工作要求(qiu)，被廣泛(fan)應(ying)用(yong)在(zai)自(zi)動化(hua)(hua)機(ji)械上(shang)(shang)比較多,像(xiang)磨(mo)床、銑(xian)床、車床、檢測(ce)儀(yi)器設(she)備、木工機(ji)械、搬運(yun)(yun)機(ji)械、傳送(song)裝置(zhi)、自(zi)動化(hua)(hua)機(ji)械、半導體機(ji)械、包裝機(ji)械、機(ji)械手(shou)臂、自(zi)動化(hua)(hua)機(ji)床、激光(guang)行(xing)業、汽車制造、新能源等行(xing)業。