The spindle on the CNC lathe drives the rotary motion of the workpiece. The spindle on the vertical machining center drives the rotary motion of the milling cutter, the boring tool and the grinding wheel. The main drive motion of the CNC machine is dragged by the main drive motor. Today we are going to talk about the shifting system of the main drive motion of CNC machine tools:
  At present, the main drive motor of CNC machine tools has basically no longer used ordinary AC asynchronous motors and traditional DC speed-regulated motors, and they are gradually replaced by emerging AC variable frequency speed control servo motors and DC servo speed control motors. The main motion of CNC machine tools requires a large speed range to ensure that the proper amount of chips can be used during machining to achieve the desired productivity, machining accuracy and surface quality. In order to meet the requirements of various workpieces and various workpiece materials, we would like to congratulate the CNC machine tools for automatic tool change and the speed control range of the main motion of the machining center should be further expanded.
  
  The shifting of the CNC machine tool is automatically performed according to the control command, so the shifting mechanism must be adapted to the requirements of automatic operation. Due to the improvement of the speed control system of the DC and AC variable speed spindle motors, it is not only convenient to realize a wide range of stepless speed change, but also reduces the intermediate transmission link and improves the reliability of the shift control, so in the main drive system of the CNC machine tool It can show its superiority.
  
  In order to ensure the torque at low speed, some CNC machine tools are equipped with gear shifting based on the continuously variable speed of AC and DC motors. Since the main motion adopts stepless speed change, constant speed chip control can be realized when measuring inclined end faces on large CNC lathes, so as to further improve production efficiency and surface quality. The main drive of CNC machine tools mainly has the following configuration modes:
  
  1. Main drive through belt drive: This is mainly used on small CNC machine tools to avoid vibration and noise caused by gear drive. But it can only be used with the spindle with the required torque characteristics.
  
  2. Main drive directly driven by the speed control motor: This main drive mode greatly simplifies the structure of the spindle housing and the spindle, and effectively improves the rigidity of the spindle components. However, the spindle output torque is small, and the motor heating has a great influence on the accuracy of the spindle.
  
  3. Main drive with variable speed gear: This is a way to use more large and large type CNC machine tools. With a few pairs of gear reductions, the output torque is increased to meet the spindle's requirements for output torque characteristics. Some small CNC machine tools use this type of transmission to obtain the torque required for strong chipping. The displacement of the slip gear is mostly achieved by using a hydraulic fork or directly driving the gear by a hydraulic cylinder.