Research Of Motorized Spindle With Ceramic Hybrid Bearings Lubricated By Water-based Lubricant

The modern equipment manufacturing industry proposes higher demand for machine tools.The motorized spindle is one of the most important components in a machine tool.The water lubricated ceramic bearing has been considered to be the best choice for high-speed and high-precision spindle.However,there are issues to be resolved,such as the lubricant,bearing materials,dynamic performance of the rotor-bearing system,design and manufacturing of the ceramic bearing and the reliability of the spindle.The research content as follows:1.The tribology properties of silica-based non-oxide ceramics were tested in different aqueous solutions of lower alcohols.The comparison was base on the quantitative results,such as friction,wear,load carrying ability and lubrication regime.The results show that:（1）The tribology properties of self-mated Si₃N₄ were influenced by the concentration of alcohols,high concentration could significantly improve the tribological properties;the high temperature of lubricant could deteriorate the tribological properties;low concentration（around 5vol.%）may deteriorate the tribological properties.（2）The tribology properties of self-mated SiC increased with the concentration of alcohols.（3）In pure water and low concentration aqueous solutions of glycol or glycerol,self-mated SiC displayed better performance;however,when the concentration was high,self-mated Si₃N₄ was better.2.The nonlinear dynamic response of rotor-bearing system was investigated.The nonlinear damping suspension was introduced to the system for vibration isolation,then the effect of the nonlinear damping suspension on nonperiodic motions of the system was discussed.And the influence of system parameters was investigated.3.To protect the ceramic bearings,a “Whole-wrap” structure design criteria was summarized.The detailed design examples were introduced based on three types of spindle arrangements,these examples have formed independent intellectual property rights system.Take universal type spindle for example,the design and manufacturing process of ceramic bearings was introduced,and the spindle was finished.4.The ceramics spindle was tested.The results show that the water-based lubricant could reduce the temperature rise significantly.And the ceramic bearings show excellent reliability and the wear resistance under water-based lubricant.