Precision high-speed electric spindles have a wide range of applications, but they also have many problems. Among them, thermal stability is a key issue that urgently needs to be addressed. whyHigh speed electric spindleWill there be any issues with thermal stability? How to overcome it? Because the electric spindle is composed of electric spindles, there is no doubt that a heat source has been added to the structure. Heat dissipation mainly includes losses in the stator winding. The heat generated by the stator winding accounts for more than two-thirds of the total heat of the motor.

The thermal radiation and heat transfer of precision high-speed electric spindles require reasonable lubrication and cooling of the spindle bearings, otherwise the high-speed operation of the electric spindle cannot be guaranteed. The cooling of the motor is more important for improving the thermal performance of the electric spindle. A circulating cooling water jacket is designed at the connection between the motor stator and the casing. Water is made of low thermal resistance materials, and the outer ring of the sleeve is equipped with a spiral shaped water tank. When the electric motor is running, circulating cooling water enters the water tank. Strictly controlling the inlet temperature of the cooling water, ensuring a certain pressure and flow rate, can improve the cooling effect. In order to prevent the motor from heating up and affecting the spindle bearings, the spindle should be made of high thermal resistance materials, so that the heat of the motor rotor is mainly transmitted to the transmission shaft through the air gap, and the cooling water maintains the stable thermal balance of the high-speed electric spindle on the transmission shaft.

In order to overcome the disadvantages of the two pre tightening methods mentioned above, the precision high-speed electric spindle can adopt a switch type pre tightening method in the spindle unit of the ultra high speed machining center, so that the spindle unit can adapt to low-speed and high load machining at the same time, and can meet the needs of ultra high speed machining. When performing low-speed heavy cutting, the bearing operates under a constant directional preload force; When performing high-speed light cutting, the system can actively switch to constant force pre tightening mode to avoid an increase in pre tightening force and improve the high-speed performance of the bearing.