Analysis On The Thermal Characteristics Of Ultra High-speed Aerostatic Motorized Spindle

Aerostatic motorized spindle was widely used in precision&ultra-high speed&light load cutting equipment because of its advantages:low friction characteristics, excellent high&low speed and high&low temperature performance, smooth movement, and high rotary precision, low noise, small vibration, compact structure, short transmission chain, higher mechanical efficiency. And thermal characteristics of aerostatic motorized spindle is the major factors to effect spindle stability and machining precision of machine tool.Therefore, researching on thermal characteristics of aerostatic motorized spindle are significant to improve the thermal stability and thermal rigidity of the spindle.At present, compared with high speed&high-power rolling bearing motorized spindle, researches on the ultra-high speed aerostatic motorized spindle are very few in domestic. In this article, the ultra-high speed aerostatic motorized spindle has been studied, using the3-D finite element modeling and simulation analysis methods to simulate thermal characteristics of aerostatic motorized spindle and carrying out the experiment research. The main research works include the following1、Internal thermodynamic characteristics of ultra-high speed aerostatic motorized spindle are analyzed.Heat generated and heat transfered mechanism arc got at adiabatic equal entropy state.The rules of heat generated and exchanged as well as factors effect temperature rise and methods for simplified model of aerostatic bearing are analyzed.2、The3-D entity modeling of ultra-high speed aerostatic motorized spindle which considerated real structure of the motor in-built and aerostatic bearing was built in order to get a more accurate finite element analysis result. The contact heat resistance was considered when dealing with the finite element analysis model according to the assembly relationship of the parts. The heat source and heat dissipation characteristics of aerostatic motorized spindle are accurately analyzed and quantitatively calculated to get heat genereated rate of main heat source and heat transfered cocfficicnt of aerostatic motorized spindle and its relationship flowing with spindle structure,spindle rotating speed,water flow of cooling system, gas flow and environment temperature.The temperature field distribution results at different operating conditions, different spindle rotating speed, different material surface emissivity are contrasted and some measures improving temperature rise of the ultra-high speed aerostatic motorized spindle are proposed.3. Finally,the thermal characteristics of ultra-high speed aerostatic motorized spindle under no-load are experimental studied.The experimental results are close to the simulation analysis results that shows3-D finite element entity model built in this article and the model processing method of aerostatic motorized spindle are reasonable; the boundary conditions calculated for the finite element simulation analysis are reasonable, and the simulation results has a certain reference value.