In the previous models of rolling bearings with a single fault, the displacement deviation caused by the collision of the fault to the rolling element changes instantly. However, the displacement deviation should change gradually. Here, the asymptotic idea is introduced to describe the change of the displacement deviation. The calculation method of the deviation is given. An asymptotic model of rolling bearings with an inner raceway fault is constructed. Then, the simulation of the SKF6205 bearing with a single fault is carried out. The differences between the previous model and the asymptotic model for the responses and the displacement deviation are compared. The effects of the speed and fault size on the dynamic characteristics are analyzed. Finally, the experiments are carried out to corroborate the rationality of the constructed model. The research results can provide theoretical support for the dynamic analysis, fault diagnosis, and reliability analysis of rolling bearings.

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Clearance between the disk and shaft can lead to the aggravation of the system fault. To solve this problem, a disk-shaft dynamic model with the clearance-eccentric coupling faults is established by the finite element method. Based upon the model, the dynamic characteristics of the system with different influence factors such as clearance and rotating speed are acquired by comprehensive analysis. Meanwhile, the accuracy of the dynamic model is verified by experiment investigations. The results show that frequency components in the spectrum include the shaft’s rotating frequency and high frequency multiplication components. And the sawtooth phenomenon from the trajectory diagram of disk center can be observed. With the increase of rotating speed, the disk-shaft contact stress and strain energy first decrease and then increase, while the speed difference of disk to shaft and vibration amplitude increase, and the number of high frequency multiplication components in the spectrum decreases gradually. Furthermore, with the increase of clearance, the stable values of the disk-shaft contact stress and strain energy decrease, while the vibration amplitude, the number of high frequency multiplication components and speed difference increase gradually, and the trajectory shape of disk center changes from closed circle to hollow ring.

This article describes the process of replacing imported bearings with domestic composite sliding bearings in the hydroelectric engineering industry from three main aspects: thrust bearing of hydraulic generator, water distributor bearing of hydraulic turbine and spherical plain bearing of steel gate of hydraulic metal structure; expounds that we have adopted the development mode of imitation and independent innovation instead of plagiarism or re-innovation after technology introduction. In the process of domestic development, we relied on our continuous learning and innovation, focused on intellectual property protection, and aimed at the advanced international level; summarizes the achievements made in the application technology level of domestic products through our own efforts over the past 40 years, i.e. achieving the replacement of imported bearings with domestic bearings and realizing the export of domestic bearings; and presents the prospect of application of composite sliding bearings in hydroelectric engineering.

At present, the majority of the research on dynamic model of rolling bearings with multiple faults is conducted on the assumption that the displacement deviation between raceway and rolling element changes instantaneously. However, the deviation should vary gradually. As a result, an asymptotic model of rolling bearings with multiple faults on outer raceway is established, considering the interaction of multiple faults. Synchroextracting transformation method is employed to describe the joint time-frequency distribution of the faulty rolling bearings. The discrepancies between the asymptotic model and the traditional model are contrasted and analyzed via simulation modeling. Simultaneously, the effects of fault number and fault interval on the joint time-frequency distribution are investigated. Finally, experiments are performed to verify the rationality of the established model. Simulation results demonstrate that the joint time-frequency distribution derived by the asymptotic model includes not only the fault characteristic frequency but also the rotating frequency. The central frequency increases in a multiple of the fault characteristic frequency as the fault number increase, as does its energy amplitude. Only when multiple faults are uniformly distributed among the interval range of rolling elements, the energy amplitude of the central frequency can reach the maximum. The energy amplitude of the rotating frequency scarcely changes as the fault interval and fault number vary.