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.

The cooling of precision electric spindles is due to the integration of the motor into the spindle unit and the high speed of the electric spindle, which generates a large amount of heat during operation, causing a temperature rise in the electric spindle and deteriorating its thermal and dynamic characteristics, thereby affecting the normal operation of the electric spindle. Therefore, certain measures need to be taken to control the temperature of the electric spindle and keep it constant within a certain value. At present, machine tools generally use the method of forced circulation oil cooling to cool the stator and spindle bearings of the electric spindle. That is to say, the cooling oil through the oil cooling device is forced to circulate outside the spindle stator and spindle bearings, taking away the heat generated by the high-speed rotation of the spindle.

When starting the electric spindle, it is necessary to ensure that the circulating cooling water required for the spindle sleeve is already turned on, and the temperature of the cooling water cannot exceed 35 ℃. Of course, it cannot be too low, nor can tap water be directly used as cooling water during the operation of the electric spindle, in order to avoid condensation of the hot air inside the electric spindle when it is cooled, which will affect insulation and bearing rust.

Secondly, the flow rate of cooling water should be controlled at 3-6L/min, and it should be clean and free of debris to prevent blockage of the channel. The water volume in the cooling water tank of the electric spindle is about 60L~100L; The inlet and outlet should not be too close to each other, so that there is a cooling process for the water in the tank, and the temperature difference between the inlet and outlet can reach a certain level to prevent hot water circulation and failure to achieve cooling effect.

In addition, in order to reduce the heat generation of precision electric spindle bearings, it is necessary to lubricate the spindle bearings reasonably.