Under the background that modern machine tools have higher requirements to the spindle system, the accuracy, stiffness, critical speed and dynamic stability of the spindle bearing also put forward higher requirements. Traditional steel spindle has been difficult to meet the needs, because of its inherent characteristics. Advanced ceramics have excellent performance, such as low density, low thermal expansion coefficient, high stiffness, wear resistance and good chemical and thermal stability, which can meet the requirements of modern machine tool spindle to the performance of bearing material. The longest fatigue life is the objective function, the calculation method of the ceramic bearing optimal design is the external point method of penalty function, and the all-ceramic bearings without inner rings are successfully manufactured by the advanced manufacturing technology. Finally, the high-speed ceramic motorized spindle prototype was assembled with high precision successfully, and its performance test and analysis were finished, the results show that using the all-ceramic bearing can effectively improve the rotation accuracy and rotational stiffness of the spindle-bearing system.

Abstract. Because of the extraordinary physical properties of engineering ceramics such as high hardness, low thermal expansion, light weight and abrasion resistant, it accommodates very well with the high-speed and precision requirements of spindle-bearing unit. In order to prove the superior dynamic characteristic of the all-ceramic spindle-bearing unit bacause of the application of engineering ceramics in shaft and bearing of spindle system, the natural frequency and modes of the all-ceramic spindle-bearing unit were analyzed. In this study, spindle-bearing model was built and analyzed by the Finite Element Method(FEM) and Hertz theory, comprehensively considering both of the stiffness of bearing and the effect of preload, which was different from the tranditional spindle analysis model. The research results show that all-ceramic spindle-bearing unit has higher natural frequency and better dynamic characteristics compare of traditional steel spindle-bearing unit.

One important demand on spindle systems in modern machine tools is to realize higher rotational speed in order to increase the machining efficiency. So, the low rotational inertia and high fundamental natural frequency are indispensable. Because of advanced ceramics' extraordinary physical properties such as high hardness, low thermal expansion, light weight, abrasion resistant and good chemical and thermal stability, it accommodates very well the high-speed and precision requirements of machine tool spindles. In this study, a high-speed ceramic spindle system equipped with high-performance structural ceramic shaft and fully-ceramic ball bearings was designed and developed. The high-speed ceramic motorized spindle prototype was assembled with high precision successfully, and its performance test and analysis were finished. The test results show that ceramic motorized spindle can reduce the high-speed rotational centrifugal force and inertia force and increase the stiffness and rotation accuracy of spindle-bearing system greatly.