Low-friction Rolled Ball Screw--SFA2510-3.8-263-335-C7---25mm Diameter Rolled Ball Screw

Installation Methods of Ball Screws

1. Fixed at both ends

Both ends of the ball screw are fixed. The bearings at the fixed ends can bear axial force simultaneously. This supporting method can apply an appropriate preload to the ball screw to a certain extent, improve the stiffness of the ball screw support, and partially compensate for the thermal deformation of the ball screw set.

2. Fixed at one end and free at the other

The industrial ball screw adopts the installation method where one end is fixed and the other end is free. The bearing at the fixed end must bear both axial force and radial force. This supporting method is suitable for short ball screws with small strokes or machine tools with full closed-loop systems. Because the mechanical positioning accuracy of this structure is relatively unreliable, especially for ball screws with a large length-diameter ratio, their thermal deformation is very obvious. It is very normal for a 1.5m-long ball screw to have a change of 0.05-0.10mm under different cold and hot environments. However, due to the simple structure of this type, it is more convenient for installation and debugging, so many high-precision machine tools still use this structure. It should be noted that a grating needs to be added, and full closed-loop feedback should be adopted.

3. Fixed at one end and supported at the other

One end of the ball screw is fixed, and the other end is supported. The fixed end also bears both axial force and radial force; the supported end only bears radial force and can make slight axial floating, which can reduce or avoid the bending caused by the self-weight of the ball screw pair to a certain extent, and at the same time, the thermal deformation of the ball screw and nut can freely extend to one end. This method should be the most widely used. At present, most domestic small and medium-sized CNC machine tools, vertical machining centers, etc., basically adopt this structure.

This method is also usually used for large machine tools, heavy-duty machine tools, and high-precision boring and milling machines. However, the adjustment of such screws will be relatively frequent. If the preload at both ends is too large, the final stroke of the ball screw with nut will be longer than the designed stroke, and the pitch will also be larger than the preset one. If the preload of the lock nuts at both ends of the screw is insufficient, the use effect may be quite unsatisfactory, which may easily cause machine tool vibration and reduce accuracy. Therefore, when loading and unloading such screws, adjustments must be made by the manufacturer's instructions or with the help of instruments and equipment. Do not handle them without authorization.