The invention exposes an electric spindle angular contact
ball bearing pre-tightening force regulating mechanism. An elastic check ring for a hole, angular contact ball bearings and an oil stopping ring are sequentially arranged on a spindle in a sleeving manner; three
layers of sleeves are installed between the bearings installed in pairs; a non-
contact type temperature sensor is installed between the bearings and the oil stopping ring; an
angular acceleration vibration sensor is installed at the
tail end of the electric spindle; and an oil spraying
nozzle is installed on the face of the outer side of the bearings. A piezoelectric
ceramic driving power source, a connector
assembly, an oil receiving
nozzle and a water receiving
nozzle are installed on an end cover on the
tail portion of the electric spindle. The piezoelectric
ceramic driving power source is connected with two annularly stacked piezoelectric
ceramic sleeves through a circuit. According to the technical scheme, by means of a good automatic pre-tightening force regulating technology, the pre-tightening force of the electric spindle bearings is effectively regulated, the electric spindle temperature rise is regulated and controlled,
noise is lowed, the supporting precision and the rotating precision of the bearings are improved, the service life of the bearings is prolonged, and therefore the dynamic performance of the electric spindle is improved, and the
machining precision and the work efficiency of a
machine tool adopting an electric spindle unit are improved.