Research On The Performance And Application Of The New Single-sided Membrane Restrictor

The non-circular curved surfaces have the merits of improving the lubrication,uniform loading,reducing the stress concentration and improving the service life.so they are generally applied in the high quality parts.However,the precision machining of the non-circular curved surface has been the key problem in the modern manufacturing technology,especially the precision machining of non-circular inner hole is more challenging.To provide a new machining method of the non-circular curved surface,this paper designed a new single-sided membrane restrictor used for controllable hydrostatic spindle.The basic theoretical studies of the radial hydrostatic bearing are carried out.The fundamental equations,such as Reynolds equation and flow continuity equation,and their computing method have been provided in this thesis.The investigation compares the four-recess hydrostatic bearings with circumferential oil-returning and without circumferential oil-returning on the structure characteristics and static performances.A simplified method of calculating the static performances of the four-recess hydrostatic bearings with circumferential oil-returning is used.Its practicability is verified by an example.An new single-sided membrane restrictor based on piezoelectric ceramic actuator is proposed in this thesis.Its structure characteristics and working principle are introduced.And the mathematical model of the membrane restrictor is proposed include the pressure and flow characteristics,the calculation formula of membrane stiffness and the stress analysis of membrane.The structural parameters optimization design of the new single-sided membrane restrictor is simplified to single objective nonlinear optimization problem.The objective of structural parameters optimization is achieved by using the Fmincon function in Matlab optimization toolbox.Two hydraulic active control systems of hydrostatic spindle are designed.The relationships between axis trajectory and piezoelectric ceramic actuator's output displacement and thrust are calculated and simulated.The paper compares the advantages and disadvantages of two hydraulic active control systems.The flow damping and stiffness of hydrostatic bearing are given.The influence of spindle eccentricity and oil pressure on the oil film stiffness coefficient and damping coefficient is analyzed.The dynamics model of the hydrostatic spindle based on the control of active single-sided membrane restrictors is established.System transfer function is given and the step response of the system is simulated in the thesis.The experiment system of the new single-sided membrane restrictor is established.The paper studies the static characteristics and the hysteresis characteristics of the piezoelectric ceramic actuator by the experiment.Piezoelectric ceramic actuator's output displacement is forecasted by using BP neural network model based on LM algorithm.The experiment of the new single-sided membrane restrictor about the dynamic response characteristics and flow characteristic is carried out.The flow formula of the membrane restrictor is obtained by using fitting process.