Selection of oil-air lubrication for high-speed electric spindle bearings1

Bearings are an indispensable part of mechanical equipment. In the motorized spindle, the reliable operation of the bearings is more important, which directly affects the performance indicators of the machine tool. In addition to the bearing performance is affected by its own material, the choice of lubrication and cooling method is also very important. To achieve high-speed cutting of machine tools, first of all, the rotational speed of the shaft must be high. High rotational speed requires stable bearing performance. Lubrication is an important factor to ensure bearing performance. Using the bearing oil and gas lubrication, the bearing can be well lubricated, the motorized spindle runs more stably, and obtains a good operating index.

Among the factors affecting the speed and performance of the electrospindle, thermal deformation is related to lubrication. The internal heat source of the electric spindle comes from two aspects: the heat generated by the built-in motor and the spindle bearing.

The heating of the spindle bearing can be solved by using oil and gas lubrication. The bearing size of the electric spindle is not too large, and does not require a large amount of lubricating oil to lubricate. If the traditional lubrication method uses a large amount of lubricating oil for invasive lubrication, the method is not desirable, mainly because it cannot provide good lubrication, and a large amount of lubricating oil will be wasted. During the continuous circulation of lubricating oil, the oil temperature will rise due to the friction between oil molecules, which is not conducive to the operation of the electric spindle. Therefore, oil and gas lubrication of bearings is selected. This micro-lubrication method can reduce the supply of lubricating oil, which not only eliminates the heat generated by the friction of a large number of oil molecules, but also has a better lubrication effect. The bearing is lubricated by oil and gas, and the oil supply follows the principle of a small amount of oil at a time. Each time, the oil is quantitatively supplied in a very small amount, and the oil supply frequency is increased to meet the lubrication requirements of the bearing. In this lubrication method, the compressed air drives the lubricating oil film to the friction surface, the lubricating oil fully plays a role in lubrication, and the compressed air can also take away the heat generated by friction and play a cooling role.

The selection of bearing oil and gas lubrication can summarize the advantages as follows:

1. The consumption of lubricating oil is low, and the cost is saved.

2. The lubrication effect is good, which ensures the design performance of the electric spindle.< /p>3. Compressed air can take away the heat generated inside the electric spindle, which can effectively prevent the bearing from being deformed due to heat.

4. The positive pressure inside the bearing prevents the intrusion of impurities.