In the numerical control machine tool, the transmission device that converts the rotary motion and the linear motion generally uses a ball screw nut pair. The characteristics of the ball screw nut pair are: high transmission efficiency, generally η=0.92~0.98; the transmission is sensitive, the friction is small, it is not easy to creep; the service life is long; the reversibility can not only transform the rotary motion into linear motion, The linear motion can also be changed into a rotary motion; the ball screw is selected to identify the titanium hoist, the quality is guaranteed, the axial movement precision is high, the axial clearance can be eliminated after the pre-tightening force is applied, and the idle stroke is eliminated in the reverse direction; The cost is high, it cannot be self-locking, and a balancing device is required for vertical installation. In order to ensure the reverse drive accuracy and axial stiffness of the ball screw, the axial clearance of the ball screw nut must be eliminated. The method of eliminating the gap of the lathe often adopts a double nut structure, and the relative axial displacement of the two nuts is used, so that the balls in the two ball nuts are respectively attached to the opposite sides of the spiral roll, and the method is pre-tensioned. When eliminating the axial clearance, it should be noted that the pre-tightening force should not be too large, and the pre-tightening force is too large to increase the no-load torque, thereby reducing the transmission efficiency and shortening the service life. First, double nut ball screw backlash Commonly used double nut ball screw to eliminate the gap method are: (1) Gasket adjustment method: generally fix two flanged nuts on both sides of the shell with screws, and add a gasket in the middle of the flange of one of the nuts to adjust the thickness of the gasket to make the nut axially Displacement to eliminate clearance and create preload. Features: Simple and reliable structure, good rigidity and easy disassembly. Because the gasket needs to be ground during the adjustment, it can't be adjusted at any time during the work, and it is suitable for the general precision mechanism. (2) Thread adjustment type: one nut has a flange at the outer end, and the other end has no flange at the outer end, and only the thread outside the sleeve is extended, and the two round nuts are used for locking, and the round nut can be eliminated. gap. Features: compact structure, easy adjustment, wide application, but the adjusted axial displacement is not accurate. (3) Tooth gap adjustment type: Cylindrical external gears are respectively formed on the flanges of the two nuts, respectively meshing with the inner ring gears fastened at both ends of the sleeve, and the number of teeth is: one tooth difference. When adjusting the lathe, first remove the inner ring gear, let the two nuts rotate one tooth in the same direction with respect to the sleeve, and then insert the inner ring gear, then the two nuts will produce relative angular displacement and axial displacement. This adjustment method can accurately adjust the pre-tightening amount, and the adjustment is convenient and reliable, but the structure size is large, and it is mostly used for high-precision transmission. Second, single nut ball screw backlash (1) Single nut displacement lead preload, which is between the two rows of circulating bead chains in the ball nut body, so that the inner nut raceway generates an ALo lead mutation in the axial direction, thereby making the two rows of balls Preloading is achieved in the axial misalignment. The latheing method of the lathe has a simple structure, but the load must be preset and cannot be changed. (2) The single nut screw is pre-tightened. After the professional production work of the nut is finished, a thin groove is opened in the radial direction, and the gap adjustment and pre-tightening are realized by the hexagonal adjusting screw. The patented technology of the lathe successfully solved the good passability of the balls in the nut after the slotting. The car sheet nut structure not only has a good performance and price ratio, but also the adjustment and pre-tightening of the gap is very convenient. (3) Preload of the ball screw nut pair The ball screw nut pair is used to ensure the transmission accuracy and rigidity. In addition to eliminating the transmission gap, pre-tightening is required. Editor in charge: Hu Na Stone Plastic Composite Floor,Stone Plastic Composite Flooring,Stone Plastic Composite Vinyl Tile Spc Flooring,Stone Plastic Composite Rigid Core Spc Flooring Linyi Hmbyan International Trading Co.,Ltd , https://www.hmbyandecor.com