Research On Hydrostatic Bearing Of Grinder Spindle Based On PM Flow Controller

As a key component which plays supporting role in the spindle system,the application of hydrostatic bearing becomes wider and wider in high efficiency and precision machine tool. The throttle,the pressure compensation component of the hydrostatic bearing,makes hydrostatic bearing have a certain carrying capacity and adapt to the load changes.PM flow controller is a single-side film throttle of oil supply preloading and preconditioning.The fluid flow of PM flow controller increases as pocket pressure rises up,thus well adapted to changes of external load,results in almost no change in hydrostatic column,therefore,huge stiffness is achieved.It's precisely because of the unique pressure-flow characteristics of PM flow controller, compared with capillaries approximately 4 times the stiffness can be achieved for comparable ratios on account of this using PM flow controllers.In this paper,we find a way of using PM flow controller in hydrostatic bearing,analyze static and dynamic property of hydrostatic bearing based on PM flow controller,so theoretical references for the design of hydrostatic bearing are provided.The main research content of this paper is represented as follows:(1)We study the deformation mechanism of thin film in PM flow controller and obtain the relationship between thin film deformation and pocket pressure.Then,use PM flow controller for 4-pockets hydrostatic centripetal bearing without returning oil slot,research on hydrostatic bearing based on PM flow controller,meanwhile,the calculation formulas for stiffness and load-bearing capacity are derived.At last,use numerical analysis to analyse the influence of static property and 7 design parameters, provides theoretical references for the actual design of hydrostatic bearing based on PM flow controller.(2)We analyze the static rigidity of hydrostatic spindle based on PM flow controller,the influence of transmission direction,the length of the grinding wheel overhanging,supporting distance between front and rear bearing,supply pressure and flow ratio on the static rigidity of hydrostatic spindle.Then improvement measures to increase the static characteristics of the spindle are put forward.(3)In order to study the dynamic property of hydrostatic bearing based on PM flow controller,combine flow continuity equation with motion differential equation of the spindle to form motion equations to describe the movement of hydrostatic bearing system,linearize the motion equations,obtain the transfer function of hydrostatic bearing system under linearization according to Laplace transform.And then exert step load and sinusoidal wave load on the hydrostatic bearing system separately,make enough use of Matlab simulink to study dynamic property of hydrostatic bearing system in time and frequency domain respectively.(4)Some experiments were done to explore the relationship between temperature rise in hydrostatic bearing and spindle speed,and at last draw a conclusion like this:temperature rise increases with the increase of the spindle speed.