In order to obtain high transmission stiffness for the feed system of CNC machine tools, in addition to strengthening the stiffness of the ball screw nut itself, the correct installation of the ball screw and the structural stiffness of its support are also factors that can not be ignored. The inaccuracy of the bearing and its support at the end of the nut seat and screw and their excessive deformation after being stressed will affect the transmission stiffness of the feed system.

因此，螺母座的孔與螺母之間必須保持良好的配合，并應(yīng)保證孔對端面的垂直度。螺母座應(yīng)增加適當(dāng)?shù)睦甙澹⒓哟舐菽缸蜋C(jī)床結(jié)合部件的面積，以提高螺母座的局部剛度和接觸剛度。

Therefore, it is necessary to keep a good fit between the hole of the nut seat and the nut, and ensure the perpendicularity of the hole to the end face. In order to improve the local stiffness and contact stiffness of the nut seat, the appropriate rib plate should be added to the nut seat, and the area of the nut seat and the joint parts of the machine tool should be increased.

滾珠絲杠的不正確及支承結(jié)構(gòu)的剛度不足，會使?jié)L珠絲桿的壽命大大下降。因此要注意軸承的選用和組合，尤其是軸向剛度要求較高。為了提高支承的軸向剛度，選擇適當(dāng)?shù)臐L動軸承及其支承方式是十分重要的。

If the ball screw is not correct and the stiffness of the supporting structure is insufficient, the service life of the ball screw will be greatly reduced. Therefore, attention should be paid to the selection and combination of bearings, especially the requirement of axial stiffness. In order to improve the axial stiffness of the bearing, it is very important to select the proper rolling bearing and its supporting mode.

(1)“雙推一自由”式這種方式適用于短絲杠。

(1) "Double push one free" type is suitable for short lead screw.

(2)“雙推一支承”式這種方式可避免絲杠因自重引起彎曲，以及高速回轉(zhuǎn)時自由端的晃動。

(2) "Double push and one support" type can avoid the bending of lead screw due to self weight and the shaking of free end when rotating at high speed.

(3)“單推一單推”或“雙推一單推”式它的優(yōu)點(diǎn)是可對絲杠進(jìn)行預(yù)拉伸安裝。預(yù)拉伸的好處有：

(3) "Single push one single push" or "double push one single push" type has the advantage that the lead screw can be pre stretched and installed. The benefits of pre stretching are:

①減少絲杠因自重引起的彎曲。

① Reduce the bending of lead screw due to self weight.

②在推力軸承預(yù)緊力大于絲杠軸向載荷1／3的條件下，絲杠拉壓剛度可提高四倍。

② When the preload of the thrust bearing is greater than 1 / 3 of the maximum axial load of the lead screw, the tension compression stiffness of the lead screw can be increased by four times.

③絲杠不會因溫升而伸長(溫升只減小預(yù)拉伸應(yīng)力)，保持了絲杠精度。此外，這種支承方式使絲杠只承受拉力，不承受壓力。因此不存在壓桿穩(wěn)定性問題。

③ The lead screw will not elongate due to temperature rise (the temperature rise only reduces the pre tensile stress), thus maintaining the accuracy of the lead screw. In addition, this supporting method makes the lead screw only bear tension, not pressure. Therefore, there is no stability problem.

(4)“雙推一雙推”式這種支承方式剛度。只要軸承無軸向間隙，絲杠的拉壓剛度可提高四倍。可以進(jìn)行預(yù)拉伸安裝，克服熱膨脹。當(dāng)溫升超過預(yù)計(jì)的溫升時，不會像“單推一單推”式那樣產(chǎn)生軸向間隙。這種支承方式的缺點(diǎn)是：實(shí)現(xiàn)預(yù)拉伸及其調(diào)整方法較第三種支承方式復(fù)雜。

(4) "Double push one double push" type has the highest stiffness. As long as the bearing has no axial clearance, the tension and compression stiffness of the lead screw can be increased by four times. It can be pre stretched to overcome thermal expansion. When the temperature rise exceeds the expected temperature rise, the axial clearance will not be generated as the "single push one single push" type. The biggest disadvantage of this supporting method is that it is more complex to realize pre stretching and its adjustment than the third one.