Large-scale machine tools, heavy-duty machine tools, and high-precision boring and milling machines mostly adopt a structure with a solid screw at both ends of the structure. In fact, there are two main structural modes for ball screws, but why use this method to fix the structure? This is a brief introduction to these two structural modes.
1. Ball screw The first type: one end is firm, one end is calm, the other end is firm, and the other end is calmly assembled. The bearing at the firm end can bear axial force and radial force at the same time, while the support method of ball screw bearing is the main support method. If it is used for a short screw bearing with a small stroke or a fully enclosed machine tool, if it is a 1.5-meter-long screw, it is a normal sign to change 0.05-0.1mm under different conditions of cold and heat. Nevertheless, because of its larger structure and easier assembly and debugging, most high-precision machine tools still adopt this structure; however, one thing that needs special stability is that when adopting this structure, a grating must be installed and a fully enclosed ring is used. Come response, in order to be able to or fully the performance of the lead screw.
Second, the second type of ball screw: one end is strong, the other end supports one end is strong, the other end supports this assembly method, the bearing of the strong end can also bear axial force and radial force at the same time, but the support can only bear radial force. It can either do a small amount of axial float, reduce or avoid the twists and turns caused by the weight of the lead screw, and thermal deformation can or calmly extend to one end. Therefore, this is the most widely used structure. At present, domestic small and medium-sized CNC lathes, vertical machining centers, etc. all adopt this structure with a firm method at both ends of the screw. Both ends of the screw are firm. With this method, the obvious advantage is that the solid-end bearing can withstand axial force at the same time, and can either apply an appropriate pre-tightening force to the screw to improve the supporting rigidity of the screw, and at the same time, it can or partially compensate the screw. The thermal deformation. Although it also has its shortcomings, that is, the use of this structure will make the ball screw scheduling work more cumbersome, but most of the installation structure mode is still adopted.
