Abstract: Considering the centrifugal force of the bearing and the gyro moment， the dynamic load balance model of the ball was established and solved by the Newton-Raphson method. Then a transient thermal network model of the paired angular contact ball bearings of machine tool feed system was created with temperature nodes selected from bearings， the screw shafts and the bearing housings， considering the contact thermal resistance between the thermal nodes of the bearings. In this model， the internal temperature change of the bearing and the viscosity-temperature effect of the lubricant were used to modify the heat generation and thermal boundary conditions of the bearing heat source in real time. The transient temperature rise curves of important nodes such as bearing housing surface at different feed rates were predicted with differential matrix using Matlab software. The temperature field of the bearing system at different speeds was analyzed. The experimental verification under the actual working conditions of the bearing system at different feed rates was carried out to prove the validity of the prediction model.

Key words: CNC machine feed system, paired angular contact ball bearings, transient thermal characteristics, thermal network method, difference matrix