How To Install The Ball Screw
1. One end is fixed and one end is free
The ball screw is installed with one end fixed and the other free. The fixed end bearing needs to bear axial force and radial force at the same time. This support method is suitable for short lead screws with small strokes or fully closed-loop machine tools. Because the mechanical positioning accuracy of this structure is relatively unreliable, especially compared with the lead screw with a larger long diameter, the thermal deformation is very obvious. The lead screw with a length of 1.5m has a 0.05- A change of 0.10mm is normal. However, because this structure is simple, it is more convenient for installation and debugging, so there are still many high-precision machine tools using this structure. It should be noted that gratings need to be installed and full closed-loop feedback is used.
2. One end is fixed and one end is supported
One end of the ball screw is fixed and the other end is supported. The fixed end also bears axial force and radial force at the same time; the support end only bears radial force, and can do a small amount of axial floating, which can reduce or avoid the bending caused by the weight of the lead screw to a certain extent, and the thermal deformation of the lead screw Able to extend freely to one end. This method should be the most widely used. At present, small and medium-sized CNC machine tools and vertical machining centers in China basically adopt this structure.
3. Both ends are fixed
Both ends of the lead screw are fixed. The fixed end bearing can bear the axial force at the same time. This kind of support method can apply a suitable pre-tightening force to the lead screw to a certain extent, improve the rigidity of the lead screw support, and partially compensate the thermal deformation of the lead screw.
This method is also usually used for large machine tools, heavy machine tools and high-precision boring and milling machines. However, the adjustment of this kind of screw will be relatively frequent. If the preload at both ends is too large, the final stroke of the screw will be longer than the designed stroke, and the pitch will be larger than the preset. If the pre-tightening force of the lock nut at both ends of the screw is insufficient, the use effect may be relatively unsatisfactory, which may easily cause the machine tool to vibrate and reduce the accuracy. Therefore, when loading and unloading the lead screw, be sure to adjust it according to the original manufacturer's instructions, or adjust it with the help of equipment, and do not handle it without authorization.