Optimal Design And Performance Research Of Hydrostatic Bearing For Grinding Wheel Spindle System Of Heavy-duty CNC Roll Grinder

The main purpose of Heavy-load CNC roll grinder is to grind large rolls and heavy back-up rolls in metallurgical industry.Its main features are super heavy,super large and super wide.At present,hydrostatic bearing is the most commonly used sliding bearing in heavy-load CNC roll grinder.The performance of hydrostatic bearing will directly affect the performance of the whole heavy-load CNC roll grinder.The grinding accuracy and bearing capacity of the spindle system of the heavy-load CNC roll grinder are determined by the working performance of the hydrostatic bearing,and the heating of the bearing will result in the degenerating of the lubricating oil and reduce the grinding accuracy of the heavy-load CNC roll grinder.Therefore,in order to meet the work performance demand of Heavy-load CNC roll grinder,it is necessary to optimize and analyze the hydrostatic bearing of Heavyload CNC roll grinder,and verify and compare its main performance.Therefore,this article mainly carries out the following research content:(1)In view of the problem that the static pressure bearing of Heavy-load CNC roll grinder is easy to be damaged due to its poor thermal performance,the improvement is made from two aspects of changing the oil chamber structure and increasing the oil groove.The performance of the static pressure bearing of Heavy-load CNC roll grinder before and after the improvement is compared and analyzed,and the structure of the static pressure bearing of Heavy-load CNC roll grinder is analyzed according to the application requirements.As to provide reference Based on this,the structure of hydrostatic bearing is improved.The main structure of Heavy-load CNC roller grinder is selected and the parameters are selected.The orifice throttle is selected as the external oil supply equipment.The relationship between pore diameter transformation of orifice restrictor and oil film clearance,bearing stiffness and friction power consumption of hydrostatic bearing is further analyzed to determine the optimal hole diameter.(2)The working parameters of hydrostatic bearing of Heavy-load CNC roll grinder are selected according to experience,which leads to the problem of poor overall performance.The multi-objective optimization of Heavy-load CNC roll grinder is carried out by using the Particle swarm optimization.The objective function is the maximum oil film stiffness,the minimum power loss and the minimum temperature rise,the penalty function is used to assign a weighted coefficient to the objective function to obtain better design parameters.Finally,the stress and deformation of the bearing Bush are compared with those before optimization by fluid-solid coupling method.The results show that the optimized structure has better performance.(3)The heavy-load CNC roller grinder is operated under heavy load,and the force of static pressure shaft is dynamic load.This part mainly studies the displacement and stress changes of static pressure bearing under dynamic load.Through this,the dynamic performance of static bearing can be determined for a period of time.If the frequency of static bearing is close to the natural frequency of the bearing body,it will cause resonance of static bearing,which will cause damage of bearing and reduce the service life of bearing.The modal analysis of static pressure bearing can get the frequency and mode of each stage of bearing,so as to avoid every frequency as far as possible,and to a large extent,eliminate resonance.But in order to ensure that the static bearing can maintain stable mechanical performance under the external interference,we need to analyze the harmonic response of the static pressure bearing.This chapter mainly analyzes the theory of stiffness theory and harmonious response of static pressure bearing,which extends from the theoretical basis to simulation.The first 10 modes of the static pressure bearing of Heavy-load CNC roller grinder are analyzed by ANSYS software.The corresponding correlation is obtained.The minimum frequency of static bearing(8269.8Hz)of Heavy-load CNC roller grinder is compared with the speed of spindle when working.The maximum speed of Heavy-load CNC roller grinder is 2000r/min,which is far less than the critical speed(75%).At the same time,the static pressure bearing is simulated according to harmonic response theory.The maximum deformation is 0.001279 mm at the resonance frequency of 3500 Hz,which is far less than the allowable deformation.(4)The oil film of hydrostatic bearing of Heavy-load CNC roll grinder is simulated by FLUENT software,the influence of different oil supply pressure and spindle speed on the temperature field and pressure field of hydrostatic bearing of Heavy-load CNC roller grinder were compared by simulation.At the same time,the influence of different oil film thickness on temperature field of hydrostatic bearing is analyzed.It provides theoretical guidance for the design and analysis of hydrostatic bearing for Heavy-load CNC roll grinder.