Precision electric spindleIt consists of a motor without a casing, a spindle, bearings, a spindle unit casing, a drive module, and a cooling device. The rotor of the motor is integrated with the spindle through a press fit method, and the spindle is supported by front and rear bearings. The stator of the motor is installed in the outer shell of the spindle unit through a cooling sleeve. The speed variation of the spindle is controlled by the spindle drive module, while the temperature rise in the spindle unit is limited by the cooling device. Sensors for measuring speed and angular displacement are installed at the rear end of the spindle, and the inner taper hole and end face at the front end are used to install cutting tools.

In CNC machine tools, precision electric spindles usually use variable frequency speed regulation. There are three main control methods: ordinary variable frequency drive and control, vector control drive and control, and direct torque control.

Ordinary frequency conversion is a scalar drive and control, with constant torque drive as its driving control characteristic, and output power is proportional to the speed. The dynamic performance of ordinary variable frequency control is not ideal, with poor control performance at low speeds, unstable output power, and no C-axis function. But due to its low price and simple structure, it is generally used in grinding machines and ordinary high-speed milling machines.

Vector control technology imitates the control of DC motors, using rotor magnetic field orientation and vector transformation methods to achieve drive and control, with good dynamic performance. The initial torque value of the vector control driver is very large, and the electric spindle itself has a simple structure and low inertia, so the starting acceleration is large. After starting, it can instantly reach the allowed maximum speed. This type of driver has two types: open-loop and closed-loop. The latter can provide feedback on position and speed, not only with better dynamic performance, but also with C-axis functionality; The former has slightly poorer dynamic performance and does not have C-axis function, but it is cheaper in price.

Direct torque control is a new high-performance AC speed regulation technology developed after vector control technology. Its control idea is novel, the system structure is simple and clear, and it is more suitable for driving high-speed electric spindles. It can better meet the dynamic and static characteristics of high-speed electric spindles, such as high speed, wide speed range, and high-speed instantaneous stop. It has become a popular technology in the field of AC transmission.

With the update of technology, the development of high-speed cutting technology, and the needs of practical applications, people have put forward increasingly high requirements for the performance of machine tool electric spindles. The development trend of electric spindle technology is mainly reflected in the following aspects:

1. Developing towards high speed, high power, and low speed, high torque.

2. Developing towards high precision and high rigidity.

3. Developing towards precise positioning (quasi stopping) direction

4. Developing towards fast start and fast stop.

5. Developing towards ultra high speed direction.

6. The standardization direction of GDZ09 electric spindle is developing. GDZ09 electric spindle is a specialized high-precision electric spindle for grinding inner holes, mainly used for precision grinding of various metal workpieces.