动静压轴承支承电主轴服役精度保持用磁力减载研究

Magnetic lightening on service precision keeping of an electric spindle system supported by hybrid bearing

为了保持动静压轴承支承电主轴的服役精度,提出采用电磁力消减静动态加工力的方案并研制了一套磁力减载系统。以磨床为例,建立电主轴系统的动力学模型,获取了载荷与轴端位移的关系;估算了磨削加工时产生的静态和动态加工力,提出了服役精度保持的静/动载荷需求;设计并建造了磁力减载系统,包括结构和测控两个模块;其中,结构模块特色在于磁力减载组件配备有万向支撑方案,测控模块支持开环和闭环两种控制策略;设计专项试验验证了减载系统的性能。研究结果表明:不转时减载组件可实现约35 N静载和28 N幅值谐波动载功能,初步证明采用电磁技术消减机床加工力是可行的。针对引入减载装置的电主轴系统,采用人工调节电流的开环控制策略更有效。

In order to keep the service precision of electric spindle supported by hybrid bearing, the method of reducing static and dynamic processing force by electromagnetic force was proposed and a magnetic lightening system was developed. Taking the grinding machine as an example, the dynamic model of the electric spindle system was established, and the relationship between force and displacement was obtained. The static and dynamic force in grinding processing were analyzed and estimated. Then the static and dynamic load demands for service precision keeping of electric spindle were put forward. The magnetic lightening system was designed and developed, which included the structure modules and the measurement-control module. A m o n g them, the feature of structure m o d u l e w a s the universal support scheme, a n d the measurement-control module supported open loop and closed loop control strategies. A special experiment was designed to verify the performance of the magnetic lightening system. It is showed that the magnetic lightening system can satisfy the function of static load 35 N and dynamic load 28 N. It is preliminarily evidenced that using electromagnetic technique to reduce machining force is feasible. For the electric spindle with lightening device, it is more effective by using an open loop load control strategy of artificial adjusting.