直(zhi)線滑動單元的簡單介(jie)紹及系統設(she)計說明：
◎直(zhi)線滑(hua)動單元又稱線軌(gui)、滑(hua)軌(gui)、線性(xing)導軌(gui)、線性(xing)滑(hua)軌(gui)，用于(yu)直(zhi)線往復運動場(chang)合(he)，擁有(you)比(bi)直(zhi)線軸承(cheng)更高的(de)額定負載， 同(tong)時(shi)可(ke)以承(cheng)擔一定的(de)扭矩(ju)，可(ke)在高負載的(de)情況下實現高精度的(de)直(zhi)線運動.
直(zhi)線滑動(dong)單元分為(wei)方(fang)形滾珠直(zhi)線滑動(dong)單元，雙軸(zhou)芯滾輪直(zhi)線滑動(dong)單元，單軸(zhou)芯直(zhi)線滑動(dong)單元。
在大陸稱直線滑動單元，臺灣一般稱線性導軌(gui)，線性滑軌(gui)。
直線運(yun)動導軌(gui)的作用是用來支撐(cheng)和(he)引導運(yun)動部件，按給定的方向做往復直線運(yun)動。依(yi)按摩(mo)擦(ca)性質(zhi)而定，直線運(yun)動導軌(gui)可以分(fen)為(wei)滑動摩(mo)擦(ca)導軌(gui)、滾動摩(mo)擦(ca)導軌(gui)、彈性摩(mo)擦(ca)導軌(gui)、流(liu)體摩(mo)擦(ca)導軌(gui)等種類。
◎直線(xian)軸承(cheng)主要用(yong)在自動(dong)化(hua)機(ji)械上比較多,像(xiang)(xiang)德國進口(kou)的機(ji)床,紙碗機(ji),激光焊接機(ji)等等,當然直線(xian)軸承(cheng)和直線(xian)軸是配(pei)套用(yong)的.像(xiang)(xiang)直線(xian)滑動單元主要(yao)是(shi)用在精度要(yao)求比(bi)較高的(de)(de)(de)機械結構上,滑(hua)塊-使運動由(you)曲線轉變為(wei)直(zhi)(zhi)線。新的(de)(de)(de)導軌(gui)(gui)系統使機床可獲得(de)快速進給速度，在主軸(zhou)轉速相同的(de)(de)(de)情況下(xia)，快速進給是(shi)直(zhi)(zhi)線滑(hua)動單元(yuan)的(de)(de)(de)特點。直(zhi)(zhi)線滑(hua)動單元(yuan)與平面導軌(gui)(gui)一(yi)(yi)樣，有兩(liang)個基本元(yuan)件(jian)；一(yi)(yi)個作(zuo)為(wei)導向的(de)(de)(de)為(wei)固(gu)定元(yuan)件(jian)，另一(yi)(yi)個是(shi)移(yi)動元(yuan)件(jian)。由(you)于(yu)直(zhi)(zhi)線滑(hua)動單元(yuan)是(shi)標準部件(jian)，對機床制(zhi)造廠(chang)來說(shuo)．唯一(yi)(yi)要(yao)做(zuo)的(de)(de)(de)只是(shi)加(jia)工(gong)一(yi)(yi)個安裝(zhuang)導軌(gui)(gui)的(de)(de)(de)平面和校調(diao)導軌(gui)(gui)的(de)(de)(de)平行(xing)度。當然，為(wei)了保證(zheng)機床的(de)(de)(de)精度，床身或立柱少(shao)量的(de)(de)(de)刮研是(shi)必不(bu)可少(shao)的(de)(de)(de)，在多數情況下(xia)，安裝(zhuang)是(shi)比(bi)較簡(jian)單的(de)(de)(de)。
作為導(dao)向的(de)導(dao)軌(gui)(gui)(gui)為淬硬鋼，經精磨后置于安裝平(ping)面(mian)(mian)上。與平(ping)面(mian)(mian)導(dao)軌(gui)(gui)(gui)比較(jiao)，直(zhi)線(xian)滑動(dong)(dong)單元橫截面(mian)(mian)的(de)幾何形(xing)狀，比平(ping)面(mian)(mian)導(dao)軌(gui)(gui)(gui)復(fu)雜(za)，復(fu)雜(za)的(de)原因(yin)是(shi)因(yin)為導(dao)軌(gui)(gui)(gui)上需(xu)要加(jia)工出溝槽，以利于滑動(dong)(dong)元件的(de)移動(dong)(dong)，溝槽的(de)形(xing)狀和數量，取決于機床要完成的(de)功能(neng)。例如：一(yi)個既承受直(zhi)線(xian)作用力，又(you)承受顛(dian)覆力矩的(de)導(dao)軌(gui)(gui)(gui)系(xi)統(tong)，與僅(jin)承受直(zhi)線(xian)作用力的(de)導(dao)軌(gui)(gui)(gui)相比．設計上有很大的(de)不同。
直(zhi)線(xian)滑(hua)(hua)動(dong)(dong)(dong)(dong)單(dan)(dan)元(yuan)(yuan)的(de)(de)(de)移動(dong)(dong)(dong)(dong)元(yuan)(yuan)件(jian)(jian)和(he)固(gu)定(ding)(ding)元(yuan)(yuan)件(jian)(jian)之(zhi)間(jian)不用(yong)(yong)(yong)中間(jian)介質，而(er)用(yong)(yong)(yong)滾動(dong)(dong)(dong)(dong)鋼(gang)(gang)(gang)球(qiu)(qiu)。因(yin)為(wei)(wei)滾動(dong)(dong)(dong)(dong)鋼(gang)(gang)(gang)球(qiu)(qiu)適應于高速運動(dong)(dong)(dong)(dong)、摩擦(ca)系數小、靈(ling)(ling)敏(min)度(du)(du)高，滿(man)足運動(dong)(dong)(dong)(dong)部件(jian)(jian)的(de)(de)(de)工(gong)作(zuo)要求，如機(ji)床(chuang)的(de)(de)(de)刀架(jia)，拖板(ban)等。直(zhi)線(xian)滑(hua)(hua)動(dong)(dong)(dong)(dong)單(dan)(dan)元(yuan)(yuan)系統(tong)的(de)(de)(de)固(gu)定(ding)(ding)元(yuan)(yuan)件(jian)(jian)(導(dao)(dao)(dao)軌(gui))的(de)(de)(de)基(ji)本功(gong)能如同軸承環，安裝鋼(gang)(gang)(gang)球(qiu)(qiu)的(de)(de)(de)支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)架(jia)，形狀為(wei)(wei)“v”字形。支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)架(jia)包裹著導(dao)(dao)(dao)軌(gui)的(de)(de)(de)頂部和(he)兩側面(mian)。為(wei)(wei)了支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)撐機(ji)床(chuang)的(de)(de)(de)工(gong)作(zuo)部件(jian)(jian)，一(yi)套(tao)直(zhi)線(xian)滑(hua)(hua)動(dong)(dong)(dong)(dong)單(dan)(dan)元(yuan)(yuan)至少(shao)有四個支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)架(jia)。用(yong)(yong)(yong)于支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)撐大型的(de)(de)(de)工(gong)作(zuo)部件(jian)(jian)，支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)架(jia)的(de)(de)(de)數量可以(yi)多于四個。 機(ji)床(chuang)的(de)(de)(de)工(gong)作(zuo)部件(jian)(jian)移動(dong)(dong)(dong)(dong)時，鋼(gang)(gang)(gang)球(qiu)(qiu)就在(zai)支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)架(jia)溝槽中循環流(liu)動(dong)(dong)(dong)(dong)，把支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)架(jia)的(de)(de)(de)磨(mo)損量分(fen)攤到(dao)各個鋼(gang)(gang)(gang)球(qiu)(qiu)上，從而(er)延長直(zhi)線(xian)滑(hua)(hua)動(dong)(dong)(dong)(dong)單(dan)(dan)元(yuan)(yuan)的(de)(de)(de)使用(yong)(yong)(yong)壽命。為(wei)(wei)了消除支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)架(jia)與導(dao)(dao)(dao)軌(gui)之(zhi)間(jian)的(de)(de)(de)間(jian)隙，預加(jia)(jia)負(fu)(fu)載(zai)能提高導(dao)(dao)(dao)軌(gui)系統(tong)的(de)(de)(de)穩定(ding)(ding)性，預加(jia)(jia)負(fu)(fu)荷的(de)(de)(de)獲得．是在(zai)導(dao)(dao)(dao)軌(gui)和(he)支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)架(jia)之(zhi)間(jian)安裝超尺寸(cun)的(de)(de)(de)鋼(gang)(gang)(gang)球(qiu)(qiu)。鋼(gang)(gang)(gang)球(qiu)(qiu)直(zhi)徑公(gong)差為(wei)(wei)±20微米，以(yi)0.5微米為(wei)(wei)增量，將鋼(gang)(gang)(gang)球(qiu)(qiu)篩選分(fen)類，分(fen)別(bie)裝到(dao)導(dao)(dao)(dao)軌(gui)上，預加(jia)(jia)負(fu)(fu)載(zai)的(de)(de)(de)大小，取決于作(zuo)用(yong)(yong)(yong)在(zai)鋼(gang)(gang)(gang)球(qiu)(qiu)上的(de)(de)(de)作(zuo)用(yong)(yong)(yong)力。如果(guo)作(zuo)用(yong)(yong)(yong)在(zai)鋼(gang)(gang)(gang)球(qiu)(qiu)上的(de)(de)(de)作(zuo)用(yong)(yong)(yong)力太大，鋼(gang)(gang)(gang)球(qiu)(qiu)經受預加(jia)(jia)負(fu)(fu)荷時間(jian)過長，導(dao)(dao)(dao)致支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)架(jia)運動(dong)(dong)(dong)(dong)阻(zu)力增大。這里就有一(yi)個平(ping)衡作(zuo)用(yong)(yong)(yong)問題(ti)；為(wei)(wei)了提高系統(tong)的(de)(de)(de)靈(ling)(ling)敏(min)度(du)(du)，減(jian)(jian)少(shao)運動(dong)(dong)(dong)(dong)阻(zu)力，相應地要減(jian)(jian)少(shao)預加(jia)(jia)負(fu)(fu)荷，而(er)為(wei)(wei)了提高運動(dong)(dong)(dong)(dong)精度(du)(du)和(he)精度(du)(du)的(de)(de)(de)保持(chi)性，要求有足夠的(de)(de)(de)預加(jia)(jia)負(fu)(fu)數，這是矛盾的(de)(de)(de)兩方面(mian)。
工(gong)作時間過長(chang)，鋼(gang)球(qiu)開(kai)始(shi)(shi)磨損，作用在鋼(gang)球(qiu)上的預(yu)加負載開(kai)始(shi)(shi)減(jian)弱，導(dao)致(zhi)機床(chuang)工(gong)作部(bu)件(jian)運動(dong)精度(du)的降低。如(ru)果要保(bao)持初始(shi)(shi)精度(du)，必須更(geng)換導(dao)軌支架，甚至更(geng)換導(dao)軌。如(ru)果導(dao)軌系(xi)統已(yi)有(you)預(yu)加負載作用。系(xi)統精度(du)已(yi)喪失，唯一(yi)的方法是更(geng)換滾動(dong)元件(jian)。
導(dao)(dao)軌(gui)系(xi)統的(de)(de)設計，力求固(gu)定元件(jian)和(he)移動元件(jian)之間有(you)最(zui)大的(de)(de)接觸(chu)(chu)面(mian)積(ji)(ji)，這不但能(neng)提高系(xi)統的(de)(de)承載能(neng)力，而且系(xi)統能(neng)承受間歇切削(xue)或重力切削(xue)產生的(de)(de)沖擊力，把作用力廣泛擴散，擴大承受力的(de)(de)面(mian)積(ji)(ji)。為(wei)(wei)(wei)了實現這一(yi)(yi)點(dian)，導(dao)(dao)軌(gui)系(xi)統的(de)(de)溝槽(cao)形(xing)(xing)狀有(you)多(duo)種(zhong)(zhong)多(duo)樣，具有(you)代表性(xing)(xing)的(de)(de)有(you)兩種(zhong)(zhong)，一(yi)(yi)種(zhong)(zhong)稱為(wei)(wei)(wei)哥(ge)待(dai)式(尖拱式)，形(xing)(xing)狀是(shi)半圓的(de)(de)延(yan)伸，接觸(chu)(chu)點(dian)為(wei)(wei)(wei)頂點(dian)；另一(yi)(yi)種(zhong)(zhong)為(wei)(wei)(wei)圓弧形(xing)(xing)，同(tong)樣能(neng)起相同(tong)的(de)(de)作用。無論哪(na)一(yi)(yi)種(zhong)(zhong)結(jie)構形(xing)(xing)式，目(mu)的(de)(de)只(zhi)有(you)一(yi)(yi)個，力求更(geng)多(duo)的(de)(de)滾(gun)動鋼球半徑與導(dao)(dao)軌(gui)接觸(chu)(chu)(固(gu)定元件(jian))。決定系(xi)統性(xing)(xing)能(neng)特點(dian)的(de)(de)因素是(shi)：滾(gun)動元件(jian)怎樣與導(dao)(dao)軌(gui)接觸(chu)(chu)，這是(shi)問題的(de)(de)關鍵。
◎直(zhi)線滑(hua)動單元又稱線軌(gui)、滑(hua)軌(gui)、線性(xing)導軌(gui)、線性(xing)滑(hua)軌(gui)，用于(yu)直(zhi)線往復運動場(chang)合(he)，擁有(you)比(bi)直(zhi)線軸承(cheng)更高的(de)額定負載， 同(tong)時(shi)可(ke)以承(cheng)擔一定的(de)扭矩(ju)，可(ke)在高負載的(de)情況下實現高精度的(de)直(zhi)線運動.
直(zhi)線滑動(dong)單元分為(wei)方(fang)形滾珠直(zhi)線滑動(dong)單元，雙軸(zhou)芯滾輪直(zhi)線滑動(dong)單元，單軸(zhou)芯直(zhi)線滑動(dong)單元。
在大陸稱直線滑動單元，臺灣一般稱線性導軌(gui)，線性滑軌(gui)。
直線運(yun)動導軌(gui)的作用是用來支撐(cheng)和(he)引導運(yun)動部件，按給定的方向做往復直線運(yun)動。依(yi)按摩(mo)擦(ca)性質(zhi)而定，直線運(yun)動導軌(gui)可以分(fen)為(wei)滑動摩(mo)擦(ca)導軌(gui)、滾動摩(mo)擦(ca)導軌(gui)、彈性摩(mo)擦(ca)導軌(gui)、流(liu)體摩(mo)擦(ca)導軌(gui)等種類。
◎直線(xian)軸承(cheng)主要用(yong)在自動(dong)化(hua)機(ji)械上比較多,像(xiang)(xiang)德國進口(kou)的機(ji)床,紙碗機(ji),激光焊接機(ji)等等,當然直線(xian)軸承(cheng)和直線(xian)軸是配(pei)套用(yong)的.像(xiang)(xiang)直線(xian)滑動單元主要(yao)是(shi)用在精度要(yao)求比(bi)較高的(de)(de)(de)機械結構上,滑(hua)塊-使運動由(you)曲線轉變為(wei)直(zhi)(zhi)線。新的(de)(de)(de)導軌(gui)(gui)系統使機床可獲得(de)快速進給速度，在主軸(zhou)轉速相同的(de)(de)(de)情況下(xia)，快速進給是(shi)直(zhi)(zhi)線滑(hua)動單元(yuan)的(de)(de)(de)特點。直(zhi)(zhi)線滑(hua)動單元(yuan)與平面導軌(gui)(gui)一(yi)(yi)樣，有兩(liang)個基本元(yuan)件(jian)；一(yi)(yi)個作(zuo)為(wei)導向的(de)(de)(de)為(wei)固(gu)定元(yuan)件(jian)，另一(yi)(yi)個是(shi)移(yi)動元(yuan)件(jian)。由(you)于(yu)直(zhi)(zhi)線滑(hua)動單元(yuan)是(shi)標準部件(jian)，對機床制(zhi)造廠(chang)來說(shuo)．唯一(yi)(yi)要(yao)做(zuo)的(de)(de)(de)只是(shi)加(jia)工(gong)一(yi)(yi)個安裝(zhuang)導軌(gui)(gui)的(de)(de)(de)平面和校調(diao)導軌(gui)(gui)的(de)(de)(de)平行(xing)度。當然，為(wei)了保證(zheng)機床的(de)(de)(de)精度，床身或立柱少(shao)量的(de)(de)(de)刮研是(shi)必不(bu)可少(shao)的(de)(de)(de)，在多數情況下(xia)，安裝(zhuang)是(shi)比(bi)較簡(jian)單的(de)(de)(de)。
作為導(dao)向的(de)導(dao)軌(gui)(gui)(gui)為淬硬鋼，經精磨后置于安裝平(ping)面(mian)(mian)上。與平(ping)面(mian)(mian)導(dao)軌(gui)(gui)(gui)比較(jiao)，直(zhi)線(xian)滑動(dong)(dong)單元橫截面(mian)(mian)的(de)幾何形(xing)狀，比平(ping)面(mian)(mian)導(dao)軌(gui)(gui)(gui)復(fu)雜(za)，復(fu)雜(za)的(de)原因(yin)是(shi)因(yin)為導(dao)軌(gui)(gui)(gui)上需(xu)要加(jia)工出溝槽，以利于滑動(dong)(dong)元件的(de)移動(dong)(dong)，溝槽的(de)形(xing)狀和數量，取決于機床要完成的(de)功能(neng)。例如：一(yi)個既承受直(zhi)線(xian)作用力，又(you)承受顛(dian)覆力矩的(de)導(dao)軌(gui)(gui)(gui)系(xi)統(tong)，與僅(jin)承受直(zhi)線(xian)作用力的(de)導(dao)軌(gui)(gui)(gui)相比．設計上有很大的(de)不同。
直(zhi)線(xian)滑(hua)(hua)動(dong)(dong)(dong)(dong)單(dan)(dan)元(yuan)(yuan)的(de)(de)(de)移動(dong)(dong)(dong)(dong)元(yuan)(yuan)件(jian)(jian)和(he)固(gu)定(ding)(ding)元(yuan)(yuan)件(jian)(jian)之(zhi)間(jian)不用(yong)(yong)(yong)中間(jian)介質，而(er)用(yong)(yong)(yong)滾動(dong)(dong)(dong)(dong)鋼(gang)(gang)(gang)球(qiu)(qiu)。因(yin)為(wei)(wei)滾動(dong)(dong)(dong)(dong)鋼(gang)(gang)(gang)球(qiu)(qiu)適應于高速運動(dong)(dong)(dong)(dong)、摩擦(ca)系數小、靈(ling)(ling)敏(min)度(du)(du)高，滿(man)足運動(dong)(dong)(dong)(dong)部件(jian)(jian)的(de)(de)(de)工(gong)作(zuo)要求，如機(ji)床(chuang)的(de)(de)(de)刀架(jia)，拖板(ban)等。直(zhi)線(xian)滑(hua)(hua)動(dong)(dong)(dong)(dong)單(dan)(dan)元(yuan)(yuan)系統(tong)的(de)(de)(de)固(gu)定(ding)(ding)元(yuan)(yuan)件(jian)(jian)(導(dao)(dao)(dao)軌(gui))的(de)(de)(de)基(ji)本功(gong)能如同軸承環，安裝鋼(gang)(gang)(gang)球(qiu)(qiu)的(de)(de)(de)支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)架(jia)，形狀為(wei)(wei)“v”字形。支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)架(jia)包裹著導(dao)(dao)(dao)軌(gui)的(de)(de)(de)頂部和(he)兩側面(mian)。為(wei)(wei)了支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)撐機(ji)床(chuang)的(de)(de)(de)工(gong)作(zuo)部件(jian)(jian)，一(yi)套(tao)直(zhi)線(xian)滑(hua)(hua)動(dong)(dong)(dong)(dong)單(dan)(dan)元(yuan)(yuan)至少(shao)有四個支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)架(jia)。用(yong)(yong)(yong)于支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)撐大型的(de)(de)(de)工(gong)作(zuo)部件(jian)(jian)，支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)架(jia)的(de)(de)(de)數量可以(yi)多于四個。 機(ji)床(chuang)的(de)(de)(de)工(gong)作(zuo)部件(jian)(jian)移動(dong)(dong)(dong)(dong)時，鋼(gang)(gang)(gang)球(qiu)(qiu)就在(zai)支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)架(jia)溝槽中循環流(liu)動(dong)(dong)(dong)(dong)，把支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)架(jia)的(de)(de)(de)磨(mo)損量分(fen)攤到(dao)各個鋼(gang)(gang)(gang)球(qiu)(qiu)上，從而(er)延長直(zhi)線(xian)滑(hua)(hua)動(dong)(dong)(dong)(dong)單(dan)(dan)元(yuan)(yuan)的(de)(de)(de)使用(yong)(yong)(yong)壽命。為(wei)(wei)了消除支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)架(jia)與導(dao)(dao)(dao)軌(gui)之(zhi)間(jian)的(de)(de)(de)間(jian)隙，預加(jia)(jia)負(fu)(fu)載(zai)能提高導(dao)(dao)(dao)軌(gui)系統(tong)的(de)(de)(de)穩定(ding)(ding)性，預加(jia)(jia)負(fu)(fu)荷的(de)(de)(de)獲得．是在(zai)導(dao)(dao)(dao)軌(gui)和(he)支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)架(jia)之(zhi)間(jian)安裝超尺寸(cun)的(de)(de)(de)鋼(gang)(gang)(gang)球(qiu)(qiu)。鋼(gang)(gang)(gang)球(qiu)(qiu)直(zhi)徑公(gong)差為(wei)(wei)±20微米，以(yi)0.5微米為(wei)(wei)增量，將鋼(gang)(gang)(gang)球(qiu)(qiu)篩選分(fen)類，分(fen)別(bie)裝到(dao)導(dao)(dao)(dao)軌(gui)上，預加(jia)(jia)負(fu)(fu)載(zai)的(de)(de)(de)大小，取決于作(zuo)用(yong)(yong)(yong)在(zai)鋼(gang)(gang)(gang)球(qiu)(qiu)上的(de)(de)(de)作(zuo)用(yong)(yong)(yong)力。如果(guo)作(zuo)用(yong)(yong)(yong)在(zai)鋼(gang)(gang)(gang)球(qiu)(qiu)上的(de)(de)(de)作(zuo)用(yong)(yong)(yong)力太大，鋼(gang)(gang)(gang)球(qiu)(qiu)經受預加(jia)(jia)負(fu)(fu)荷時間(jian)過長，導(dao)(dao)(dao)致支(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)架(jia)運動(dong)(dong)(dong)(dong)阻(zu)力增大。這里就有一(yi)個平(ping)衡作(zuo)用(yong)(yong)(yong)問題(ti)；為(wei)(wei)了提高系統(tong)的(de)(de)(de)靈(ling)(ling)敏(min)度(du)(du)，減(jian)(jian)少(shao)運動(dong)(dong)(dong)(dong)阻(zu)力，相應地要減(jian)(jian)少(shao)預加(jia)(jia)負(fu)(fu)荷，而(er)為(wei)(wei)了提高運動(dong)(dong)(dong)(dong)精度(du)(du)和(he)精度(du)(du)的(de)(de)(de)保持(chi)性，要求有足夠的(de)(de)(de)預加(jia)(jia)負(fu)(fu)數，這是矛盾的(de)(de)(de)兩方面(mian)。
工(gong)作時間過長(chang)，鋼(gang)球(qiu)開(kai)始(shi)(shi)磨損，作用在鋼(gang)球(qiu)上的預(yu)加負載開(kai)始(shi)(shi)減(jian)弱，導(dao)致(zhi)機床(chuang)工(gong)作部(bu)件(jian)運動(dong)精度(du)的降低。如(ru)果要保(bao)持初始(shi)(shi)精度(du)，必須更(geng)換導(dao)軌支架，甚至更(geng)換導(dao)軌。如(ru)果導(dao)軌系(xi)統已(yi)有(you)預(yu)加負載作用。系(xi)統精度(du)已(yi)喪失，唯一(yi)的方法是更(geng)換滾動(dong)元件(jian)。
導(dao)(dao)軌(gui)系(xi)統的(de)(de)設計，力求固(gu)定元件(jian)和(he)移動元件(jian)之間有(you)最(zui)大的(de)(de)接觸(chu)(chu)面(mian)積(ji)(ji)，這不但能(neng)提高系(xi)統的(de)(de)承載能(neng)力，而且系(xi)統能(neng)承受間歇切削(xue)或重力切削(xue)產生的(de)(de)沖擊力，把作用力廣泛擴散，擴大承受力的(de)(de)面(mian)積(ji)(ji)。為(wei)(wei)(wei)了實現這一(yi)(yi)點(dian)，導(dao)(dao)軌(gui)系(xi)統的(de)(de)溝槽(cao)形(xing)(xing)狀有(you)多(duo)種(zhong)(zhong)多(duo)樣，具有(you)代表性(xing)(xing)的(de)(de)有(you)兩種(zhong)(zhong)，一(yi)(yi)種(zhong)(zhong)稱為(wei)(wei)(wei)哥(ge)待(dai)式(尖拱式)，形(xing)(xing)狀是(shi)半圓的(de)(de)延(yan)伸，接觸(chu)(chu)點(dian)為(wei)(wei)(wei)頂點(dian)；另一(yi)(yi)種(zhong)(zhong)為(wei)(wei)(wei)圓弧形(xing)(xing)，同(tong)樣能(neng)起相同(tong)的(de)(de)作用。無論哪(na)一(yi)(yi)種(zhong)(zhong)結(jie)構形(xing)(xing)式，目(mu)的(de)(de)只(zhi)有(you)一(yi)(yi)個，力求更(geng)多(duo)的(de)(de)滾(gun)動鋼球半徑與導(dao)(dao)軌(gui)接觸(chu)(chu)(固(gu)定元件(jian))。決定系(xi)統性(xing)(xing)能(neng)特點(dian)的(de)(de)因素是(shi)：滾(gun)動元件(jian)怎樣與導(dao)(dao)軌(gui)接觸(chu)(chu)，這是(shi)問題的(de)(de)關鍵。
