The key to the internal support of precision electric spindles in machine tools is the spindle bearings, which bear large radial and axial loads and require high rotational accuracy, low temperature rise, maximum radial and axial stiffness, and a long service life to maintain accuracy. Therefore, the performance of the electric spindle is crucial for its functional use.

Precision electric spindleBy adopting new smelting technologies and equipment, or improving traditional smelting processes and equipment, the oxygen content and number of inclusions in steel can be reduced, the distribution, size, and shape of inclusions can be improved, and the crystallization state can be improved, thereby improving the metallurgical quality of the original steel grades and producing long-life, pure, or ultra-high purity steel.

The replacement of precision electric spindles needs to follow certain principles, otherwise improper operation can easily cause damage. The replacement of machine tool spindle bearings needs to follow three principles:

(1) Allowable speed

In a correctly installed and well lubricated environment, it is allowed to be 0.3 to 0.5 times the maximum speed of the bearing. Under normal circumstances, it is more appropriate to use 0.2 times the maximum speed.

(2) Allow tilt angle

In general, bearings do not allow the shaft to tilt relative to the housing hole, and if there is tilt, it should not exceed 2 °.

(3) Allowable temperature

Under normal load conditions, lubricants with high temperature resistance and sufficient lubrication, the spindle bearings of general machine tools are allowed to operate at ambient temperatures ranging from -30 ℃ to 150 ℃.

The general fit between a precision electric spindle and a shaft is a transitional fit, while the general fit between a seat ring and a bearing seat hole is a clearance fit. The central axis ring of a bidirectional bearing should be fixed on the shaft to prevent rolling relative to the shaft. If the installation is reversed, not only will the spindle bearings of the machine tool not work properly, but various mating surfaces will also be damaged.