静压气浮直驱转台热特性

以开发满足精密工程应用的静压气浮直驱转台为目标，研究静压气浮直驱转台结构的热稳定性.首先，分析了静压气浮直驱转台的发热-传热特性，建立了三维热特性有限元模型，计算了气浮直驱转台的温度场云图；用间接耦合的分析方法，将温度场作加载条件，进行转台热-结构耦合分析；然后，对比研究了两种直驱电机安置结构对转台热稳定性的影响，提出了静压气浮直驱转台的空气强制对流冷却方案；最后，完成了无框力矩电机后置式静压气浮直驱转台的温度场检测实验.实验结果表明，静压气浮直驱转台测试点的计算与实测温度的最大误差为1.93 ℃，稳态温度场分布计算精度较高；温度分布稳态时，气浮转台止推轴承气膜单侧间隙的变化量为0.55 μm，在空气轴承气膜设计允许的波动范围内，对轴承性能不产生明显的影响.电机后置式直驱静压气浮转台结构的热稳定性好，适合工业应用.

Thermal characteristic of aerostatic direct-driven rotary stage

In order to develop a precision aerostatic direct-driven rotary stage for precision engineering application, the thermal structure stability and forced cooling method were investigated. First, the heat generation and heat transfer characteristics of this aerostatic direct-driven rotary stage were analyzed, and finite element model of thermal characteristics was set up. The temperature field distribution in the aerostatic direct-driven rotary table was obtained. Then, according to the indirect coupling analysis method, the thermal-structural coupling deformation of the rotary stage was calculated by taking the temperature field as loading conditions. Next, through comparing thermal deformation, the aerostatic direct-driven rotary stage structure thermal stability was discussed, and an air forced convection cooling method and the gas circuit design were provided. Finally, temperature field distribution test experiments were carried out. Experimental results indicate that temperature field distribution calculator precision is high, and maximum bias of the finite element calculation is 1.93 ℃, and the air film thickness change of the thrust air bearing is less than 0.55 μm which is within the permitted range and has no effect on air bearing performance. The rear-motor aerostatic direct-driven rotary stage has good thermal stability and is suitable for industrial application.