Multi-objective optimization design algorithm of dynamic and thermal performances of high speed spindle bearing
A multi-objective optimization design algorithm model for dynamic and thermal properties analysis of high speed spindle bearing is constructed. Stiffness of bearing can be obtained by solving equilibrium equations of inner ring of bearing. Heat generation of the high speed ball bearing is studied by analyzing the local friction in the bearing considering coupling of dynamic properties, a new model for evaluating bearing temperature is set up treating the contact surfaces between rolling elements and raceways as moving heat sources. Based on this model, multi-objective optimization of stiffness and temperature rising of high speed spindle bearings are studied. Pareto-optimal solution of high speed spindle bearing are given.
Thermal-mechanical fully coupled analysis of high-speed angular contact ball bearings
The thermal and mechanical properties of angular contact ball bearings are critical to their operating accuracy and service life. On the basis of the theory of dynamics and frictional heat generation, this work establishes a thermal-mechanical fully coupled model. The high-speed motion characteristics, temperature, and dynamic stiffness are analyzed, and the simulation results are compared with the theoretical calculation and experimental results. Then, the temperature and axial deformation of the bearings under different rotation speeds are analyzed, and the laws of mechanical and thermal characteristics of the bearings are obtained. Results show that an increase in the rotation speed of the inner ring causes the temperature of each component to increase, with the contact area of the balls showing the greatest increase in temperature. An increase in rotation speed also increases the axial deformation of the inner ring.
Temperature rise of hybrid ceramic and steel ball bearings with oil-mist lubrication©
Temperature rise of ball bearings is the limiting factor to increase rotating speeds. Ball bearings with ceramic balls have been gradually used on many high speed rotating systems due to low material density, low thermal expansion, high Youngs modulus and hardness. Because of high cooling efficiency and low equipment cost, oil-mist lubricating systems have been widely used on various ball bearing systems. Oil-mist lubrication can pravide ball bearings with steady air flow and continuous lubricating oil. A test rig for high-speed ball bearings with different lubrication systems has been developed. Performance tests of hybrid ceramic and steel ball bearings under different operating conditions including preload, air flow rate, oil quantity, and rotating speed were conducted in this test rig. The authors test results show that the proper preload of hybrid ceramie ball bearings is lower than that of steel ball bearings. The temperature of ball bearings increase with the rotating speed and the hybrid ceramic ball bearing always has lower temperature rise than the steel ball bearing. When the oil supply rate is larger than the proper range, the temperature rise of hybrid ceramic ball bearing and steel ball bearing gets closer. Increasing the air flow rate is an efficient way to reduce temperature rise of ball bearings.