CNC machining of the main transmission configuration

1. Variable speed gear transmission

The main shaft motor changes speed through two gears, so that the main shaft gets two speed series of low speed and high speed, so that it becomes section stepless speed regulation. When the speed is reduced by gear transmission, the output torque and speed adjustment range are expanded, especially the speed adjustment range of the constant power output of the spindle to meet the requirements of the output torque, power characteristics and speed adjustment range of the spindle. This kind of configuration way is used more in big, medium numerical control machine tool.

2. Belt transmission

The spindle motor transmits its motion through the toothed synchronous belt to the spindle in a constant ratio transmission. This configuration mode has stable transmission, simple structure and convenient installation and debugging. It is mainly used in small CNC machine tools, but only for the spindle with low torque.

3. Direct drive mode of speed-regulating motor

There are two types of this configuration. The output shaft of the spindle motor is directly connected with the spindle through the precision coupling, which has the advantages of compact structure and high transmission efficiency, but the variation of spindle speed and torque output is completely consistent with the output characteristics of the motor, so it is limited in use. With the improvement of the performance of the spindle motor, this method will be used more and more. As shown in figure 6-2d), the spindle is integrated with the motor rotor, which is called the inner motor spindle. The advantages of this mode are that the structure of the spindle is more compact, the stiffness is high, the weight is light, the inertia is small, the response frequency of starting and stopping can be improved, and it is helpful to control vibration and noise.