Design And Performance Test Of Bi-cone Hydrostatic Spindle

Ultra-precision machining technology is very important to the entire manufacturing industry.Ultra-precision machining relies on ultra-precision CNC machine tools.The hydrostatic spindle and turntable are the key components of ultra-precision CNC machine tools.Therefore,the development is of great significance to the development of the hydrostatic spindle.In view of the existing problems in the processing of the polygonal Fresnel structure of the roller mold,this topic proposes a four-axis linkage radial Fresnel cutting method for the cylindrical surface of the roller.Now it is necessary to modify the existing roller machine tool in the laboratory.Add a low-speed and high-stability hydrostatic rotary A-axis to the X-axis of the roller machine tool,and develop a compact hydrostatic direct-drive rotary shaft for tool installation.In this paper,a bi-conic hydrostatic spindle with high rigidity and good stability is designed,and the calculation formulas for the bearing capacity,stiffness,friction torque and temperature rise of the bi-conic hydrostatic bearing are deduced,and its manufacturing process.The control system has been systematically studied,and the performance of the main shaft has been tested and analyzed,which laid the foundation for the development of this type of hydrostatic main shaft.The research work of the thesis mainly includes:1.Overall scheme design.In this paper,first,In this paper,first,according to the performance indicators and use requirements required for the rotation and positioning of the A-axis,a bi-conic hydrostatic bearing is designed.The bearing can carry axial and radial loads at the same time,and it is also convenient to adjust the bearing gap.The motor is directly driven,and the circular grating is used for position feedback.2.Bearing throttling mode.The bi-conic bearing adopts the slit throttling method.Based on the calculation formula of slit throttling bearing,the rigidity and bearing capacity calculation model of double cone hydrostatic bearing is established.According to the viscous fluid shear force formula,the internal friction torque of the oil film of the hydrostatic bearing and the average temperature rise of the hydraulic oil are calculated.The theoretical calculation results of the bi-conic hydrostatic bearing are verified by the finite element simulation software.3.Design and research of spindle control system.This paper designs and studies the control system of the bi-conic hydrostatic main shaft,analyzes the control mode and control principle of the control system,establishes a closed-loop servo system model of the bi-conic hydrostatic main shaft,and derives the mathematical model of the torque motor movement.Simulink simulation is used to analyze the response speed and steady-state error of the servo system.4.The performance test of the spindle.The static stiffness and rotation accuracy of the spindle were tested.When the oil supply pressure is 1.8MPa,the axial stiffness of the bearing is about 153N/?m,the radial stiffness is about 105N/?m,and the static rotation accuracy of the spindle is better than 0.1?m.The rotation accuracy of the spindle is measured by the Lion rotation error analyzer.The radial synchronization error of the spindle is about 0.09?m,the asynchronous error is about 0.08?m,and the axial movement error is about 0.05?m.