1. The external thread of one nut is used to adjust the relative axial position of the two nuts through the round nut to realize the pre tightening.

2、在两个螺母的凸缘上分别切出齿数差为1的齿轮，两个齿轮分别与两端相应的内齿圈相啮合，内齿圈用螺钉紧固在螺母座上。

2. The gears with tooth number difference of 1 are cut out on the flanges of the two nuts. The two gears are meshed with the corresponding inner gear rings at both ends, and the inner gear rings are fastened on the nut seat with screws.

通过转动其中一个螺母，使两螺母的相互位置发生变化，以调整间隙和施加预紧力。此种方法机构简单可靠。刚性好，应用为广泛。在双螺母间加垫片的形式可有生产厂根据用户要求事先调整好预紧力，使用时装卸非常方便。

By turning one of the nuts, the mutual position of the two nuts is changed to adjust the clearance and apply the preload. This method is simple and reliable. It has good rigidity and is widely used. In the form of adding gasket between the double nuts, the manufacturer can adjust the preload in advance according to the user's requirements, so it is very convenient to unload when using.

4、将螺母的内螺纹滚道在中部的一圈上产生一个导程突变量，从而使左右端的滚珠在装配后产生轴向错位实现预紧。滚珠丝杆螺母副轴向间隙的目的：增加预紧减少反向时的空行程，出现无反向死区，同时提高了传动刚度和传动精度。

4. The internal thread raceway of the nut produces a lead mutation on the middle circle, so that the left and right end balls produce axial dislocation after assembly to realize preloading. The purpose of eliminating the axial clearance of the ball screw nut pair is to increase the preload, reduce the empty stroke in the reverse direction, so that there is no reverse dead zone, and improve the transmission stiffness and transmission accuracy.