With the advancement of industries such as high-speed railways, new energy vehicles, and wind power, bearings are frequently exposed to various electric field environments, leading to the need for lubricating oil films of bearings to withstand voltage. One of the major issues caused by the breakdown discharge process of the lubricating oil film in bearings is the generation of local instantaneous high temperatures. This temperature rise is a key factor contributing to problems such as high operating temperature of bearings, surface damage in the contact area, and degradation of lubrication performance. This research article focuses on the comprehensive influence of bearing friction and electrical factors. It establishes a heat source calculation model and a temperature field simulation model specifically for current-carrying bearings. This study analyzes both the overall temperature rise of bearings and the local temperature rise resulting from breakdown discharge. Furthermore, the accuracy of the simulation analysis is verified through experiments. The temperature field simulation and experimental results consistently indicate that electrical environmental factors can cause an increase in the overall temperature rise of a bearing. Additionally, the breakdown and discharge of the lubricating oil film generate local instantaneous high temperatures in the contact area of the bearing.

The traction motor is a crucial component of high-speed electric multiple units, and its operational reliability is directly impacted by the temperature increase in the bearings. To accurately predict and simulate the temperature change process of traction motor bearings during operation, a fluid–solid–thermal simulation analysis model of grease-lubricated deep groove ball bearings was constructed. This model aimed to simulate the temperature rise of the bearing and the grease flow process, which was validated through experiments. The results from the simulation analysis and tests indicate that the temperature in the contact zone between the bearing rolling element and the raceway, as well as the ring temperature, initially increases to a peak and then gradually decreases, eventually stabilizing once the bearing’s heat generation power and heat transfer power reach equilibrium. Furthermore, the established fluid–solid–thermal coupling simulation analysis model can accurately predict the amount of grease required for effective lubrication in the bearing cavity, which stabilizes along with the bearing temperature. The findings of this research can serve as a theoretical foundation and technical support for monitoring the health status of high-speed EMU traction motor bearings.

Blisks are complex thin-walled parts with specific structures that have narrow channels and a large degree of bowed-twisted blades. Five-axis machining technology critically influences blisk surface quality and production efficiency, as the toolpath determines machining accuracy for complex curved blades. A method of optimal cutter location calculation for linear interpolation path based on the constraint of equal theoretical machining error is proposed. Based on the kinematics model of the machine tool, the mapping relationship between the trajectory deviation of the five-axis of machine tool and the tool pose deviation in the workpiece coordinate system is established, and then the maximum overcut/undercut value under the coupling action of the tool tip deviation and the tool orientation deviation is estimated. Based on this, a method to estimate the upper limit of theoretical machining error caused during the movement of the tool along the linear path is proposed. And the algorithm for searching discrete cutter locations on the trajectory of cutting contacts is given to maximize the length of linear path based on the constraint of equal machining error. Experimental results demonstrate that the proposed method effectively reduces redundant cutter locations on linear paths and enhances blisk surface quality by replacing conventional constant chord error control with a more preblisk machining error constraint.