Analysis Of The Thermal Characteristics In Angular Contact Ball Bearings

Rolling bearings are the most common and widely used in machinery industry and play an important role in mechanical equipment. In engineering practice, the failure caused by the heat generation in rolling bearings has severe effects on the machine, and it is very important to study the temperature field of bearings. Thermal characteristics of angular contact ball bearing have been analyzed with heat transfer and tribology.Firstly, for 7005 C angular contact ball bearings lubricated with oil, a heat transfer model of thermal nodes has been built. The computing model of the temperature field has been established with the thermal network method, and the temperature for each node is obtained. Effects of the rotational speed, the load, the centrifugal force and the spinning on the bearing temperature rise are discussed. Results show that, higher speed and heavier load lead to higher temperature rise. As the rotational speed increases, effects of the centrifugal force and spinning on the temperature rise increase. Especially at high speed, effects of the centrifugal force and spinning on the temperature rise can not be neglected.Then, the temperature field is used as the the solid body temperature boundary conditions, the non-Newtonian thermal elastohydrodynamic problem of angular contact ball bearing lubricated with oil is analyzed. Results show that, when the temperature of the inner ring or the ball in rolling bearing rises, the oil film temperature becomes higher, whereas the frictional coefficient, the central and minimum film thickness decrease. The frictional coefficient of the bearing increases with the increasing characteristics shear stress.Thirdly, for 7008 C angular contact ball bearings lubricated with grease, the temperature field of angular contact ball bearings is investigated with the thermal network method and experimental method, respectively. Results show that, when the load is constant, the vibration of the bearing increases with the increase in spindle speed, and the temperature difference obtained by the two methods is larger. When the spindle speed is constant, the vibration of the bearings is relatively small with theincrease in axial load, and the temperature difference of the outer ring obtained by the two methods decreases.Finally, the temperature field of 7008 C angular contact ball bearings is investigated with the finite element method. Comparison of the solution obtained by the experiment and thermal network method is provided. Results show that, spinning should be considered for high-speed bearings. The results of the experimental method,the thermal network and finite element method are slightly different. However, with the increase in rotational speed, the variation in the temperature of the outer race is coincident for the three methods.