As the development of high-speed engines and aerospace technologies continues to advance, the demand for high-performance rolling bearings has reached unprecedented levels. This surge in demand can be attributed to the critical role that bearings play in ensuring the smooth operation of various high-speed systems. In particular, the aerospace industry relies heavily on bearings that can withstand extreme conditions while maintaining precision and reliability. One remarkable solution that has emerged to meet these demanding requirements is the use of full ceramic bearings. These bearings are engineered using advanced ceramic materials, such as silicon nitride and zirconia, for their balls and rings. The advantages of full ceramic bearings are numerous and include their exceptional hardness, high thermal shock resistance, and the ability to maintain precise performance even in the presence of high temperatures. This makes them a preferred choice for applications in micro-aircraft engines and gas turbines, where complex configurations and extreme temperatures are commonplace. However, the successful integration of full ceramic bearings into high-speed systems is not without its challenges. One of the primary issues stems from the inherent difference in thermal expansion between the ceramic outer ring and the steel inner ring. To address this discrepancy, full ceramic bearings are often installed within steel bearings. While this arrangement allows for the benefits of ceramic materials, it introduces a critical concern – the widening of the clearance between the rings at elevated temperatures.
This increase in clearance, driven by the thermal expansion disparity between ceramic and steel components, can lead to relative motion between the rings and the bearing seat. This relative motion has undesirable consequences, including impacts and additional wear on the bearing components. These adverse effects are detrimental to the precision and longevity of the bearing, which is contrary to the goals of maintaining operating accuracy in high-performance systems. Understanding the dynamic behavior of full ceramic bearings in the context of this temperature-induced clearance variation is a paramount concern. The vibration of the ball bearing-rotor system, which is central to the performance of these bearings, arises primarily from the interactions among the bearing components. This vibration is intricately linked to the impact and friction occurring between the balls and the raceways within the bearing. Numerous studies conducted in recent decades have illuminated the significance of operating temperature in bearing performance. The research has underscored the complex relationship between the temperature, the interaction of bearing components, and the resulting vibration. It is evident that temperature plays a pivotal role in determining bearing behavior, making it imperative to investigate the interactions among bearing elements across a wide temperature range. In contemporary research methods, the influence of operating temperature on ball-bearing vibration has predominantly been explored through modifications in the contact force between the balls and the raceways. However, relatively little attention has been given to the interaction between the balls and the bearing seat. This oversight is significant, especially in scenarios where full ceramic bearings are installed within steel bearings. In these cases, the clearance between the rings undergoes substantial variations as temperatures fluctuate. These changes in clearance introduce additional complexity into the system dynamics, leading to increased vibration caused by local impacts and oscillations. Furthermore, the trajectory of the outer ring within the bearing seat becomes notably intricate under these conditions.
In a new study published in the Mechanical Systems and Signal Processing Journal led by Dr. Huaitao Shi, Prof. Yangyang Li, Prof. Xiaotian Bai, Prof. Zinan Wang, Prof. Defang Zou, Prof. Zhigang Bao, and Prof. Zhong Wang from Shenyang Jianzhu University developed a dynamic model that takes into account temperature-related fit clearance and incorporates a flexible outer ring. This model enabled them to analyze the orbital and spinning motions of the outer ring at different temperatures. Several indicators were introduced to evaluate the relative motion between the outer ring and the pedestal, providing insights into dynamic behaviors based on contact theory. The dynamic model established in their study offers a comprehensive framework for examining the behavior of full ceramic bearings in wide temperature ranges. It considers the changing fit clearance due to temperature variations and elucidates the orbital and spinning motions of the outer ring.
The authors’ findings reveal that the impact of temperature on the dynamic characteristics of the bearing is achieved through changes in the clearance between the outer ring and the bearing seat, influenced by parameters such as temperature, speed, and load. Theoretical analysis of the results aligns closely with experimental findings, confirming the validity of the model. These research outcomes provide a robust theoretical foundation for the design and optimization of ceramic bearing systems in high-performance applications, particularly those characterized by wide temperature variations. In summary, the study represents a significant advancement in our understanding of full ceramic bearings’ dynamic behavior across a wide temperature range. It not only highlights the importance of temperature in bearing performance but also addresses the challenges posed by temperature-induced clearance variations when ceramic bearings are integrated into steel bearings. This research paves the way for the development of more reliable and precise bearing systems in high-speed engines and aerospace technologies, ultimately pushing the boundaries of what is achievable in these cutting-edge fields.
Huaitao Shi, Yangyang Li, Xiaotian Bai, Zinan Wang, Defang Zou, Zhigang Bao, Zhong Wang, Investigation of the orbit-spinning behaviors of the outer ring in a full ceramic ball bearing-steel pedestal system in wide temperature ranges, Mechanical Systems and Signal Processing, Volume 149, 2021, 107317,