There are three main methods to adjust the ball screw clearance:
1. Shim clearance adjustment type: usually use screws to connect the flanges of the two nuts of the ball screw, and add shims between the flanges. Adjust the thickness of the gasket to make the nut produce axial displacement, so as to eliminate the gap and produce the pretension force. This structure is characterized by simple structure, good reliability, high rigidity and convenient handling. However, the adjustment is time-consuming and cannot be adjusted at will during work, unless the gasket with different thickness is replaced.
2. Thread clearance adjustment type: the outer end of one nut has a flange and the outer end of the other nut has no flange, which is made of thread. It extends out of the sleeve and is fixed with two round nuts. When the round nut is rotated, the clearance can be eliminated and the pretension force can be generated. After adjustment, another round nut can be used to lock it.
3. Tooth difference clearance adjustment type: cylindrical gears are made on the flanges of two nuts, and the number of teeth between the two is one tooth, and they are installed in the inner gear ring, which is fixed on the sleeve with screws or locating pins. During adjustment, first remove the inner gear rings at both ends. When two ball nuts turn the same number of teeth relative to the sleeve in the same direction, one ball nut will produce relative angular displacement to the other ball nut, so that the ball nut will move relative to the spiral raceway of the ball screw, so as to eliminate the gap and apply the preload.
Source: Shanghai Huiteng
