| As one of the core functions of the machine tool,the high-speed spindle is an indispensable and important unit for realizing high-speed machining and improving the machining efficiency,and has an important influence on the machining accuracy.High-speed spindle in engineering applications will generate a lot of heat,often in the water vapor,dust and other complex processing environment.The heat generation and dust and water vapor into the inevitable will cause irreversible damage to the spindle,shortening the motorized spindle life,resulting in huge economic losses and it is very important to analyze the influence of internal air flow field on the motorized spindle cooling and sealing effect.In this thesis,the 100MD60Y4 spindle was taken as the research object,the simulation model of the internal air flow field of the spindle was established,and the influence of the spindle speed and air gap on the cooling and sealing effect was analyzed.The experimental platforms were set up to detect fluid flow and test fluid flow velocity at the outlet of the motorized spindle.The specific research content is as follows:(1)The flow field and compressibility of the internal air flow field in the spindle and the properties of the compressed air of the lubrication spindle were analyzed and studied.The N-S equations used in calculating the air flow field were analyzed and derived.(2)The internal air flow field model of the spindle was established to analyse the influence of speed and air gap on the oil lubrication of the spindle bearings,stator and rotor cooling effect.Simulation analysis pointed out that:When the rotating speed was more than 30000 r/min,the area of the high-speed flow in the stator and rotor air gaps gradually increases and the flow field was evenly distributed,and the cooling effect of the air fluid on the stator and rotor clearance gradually increased;At the same time,as the rotating speed of the spindle increased,the flow velocity in the flow field inside the bearing was even,and the cooling effect on the bearing close to the air gap was better;The change of air gap had no obvious effect on the cooling effect of the bearing part.(3)Based on the above model,taking the rotation speed and air gap as factors,the influence of compressed air lubrication on the sealing performance of the oil-gas lubrication motorized spindle was simulated.Simulation analysis pointed out that:The front-end outlet air fluid was unevenly distributed and the sealing effect was poor at low speeds;At high speed,radial velocity gradient was formed along the front circular outlet,and the fluid distribution was uniform;During the process of gradually increasing the speed of the motorized spindle,the mean value of the flow velocity about the air fluid at the outlet was increasesd and the sealing effect was better;When the speed was increased to 24000r/min,the area of the negative pressure area in the radial direction at the exit of the front end of the electric spindle gradually increasesed,and the phenomenon of backflow gradually became serious,and the sealing effect became worse;Meanwhile,the larger for the gap,the front end of the spindle air outlet fluid flow rate increased more sensitive;When the rotation speed was increased to 24000r/min,the larger about the air gap,the backflow phenomenon was more serioused and the worse the sealing effect was.(4)The front fluid flow test platform was set up and the fluid flow front of the spindle was experimentally studied.The experimental platform of air flow velocity detection on both ends of the main shaft was established for the velocity test of air flow at both ends about the motorized spindle under different speed and different air gap conditions;The experimental results showed that the relative error of the air flow velocity and the simulation error of the two terminals are 7.2%and 3.1%respectively,and the simulation results are proved to be reliable... |
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