Machining Method And Tool Design For Stator Mould Core Of Elliptical Screw Pump

The oil extraction screw pump is a widely used oilfield mechanical oil extraction equipment.The double-head single screw pump is far superior to the single-head single screw pump in terms of displacement,efficiency,energy consumption and force status.It is mainly composed of a nitrile rubber stator and a metal rotor.The elliptical screw pump is a new type of screw pump.It overcomes the snapping phenomenon in the isometric design of the stator and rotor lines of the traditional cycloid screw pump.It can effectively reduce the meshing error between the stator and the rotor and improve the screw pump.The working performance and service life.At present,the production of nitrile rubber stators is inseparable from the stator core,and the common screw stator core processing methods also have certain limitations,such as low processing efficiency,poor accuracy or complex processing parameter configuration.Therefore,based on the linear analysis of the stator and rotor of a kind of ellipse-like doublehead single screw pump,combined with the motion law of envelope milling,the ellipse-like double-head single screw pump stator cores with different leads are developed.Tool.This paper analyzes the formation of the helical curved surface of the stator core of the elliptical single-screw pump.The elliptical rotor is used to envelop the core line of the stator according to the internal rolling method.From the cross-section profile of the stator core,a three-dimensional model of the stator core is established.Analyze the section parameters of the stator core,and determine the relationship between the cross-section curve perpendicular to the end of the stator core and the set of section points according to the characteristic equation of the stator core helical surface.According to the movement mode of the tool and the workpiece for machining the stator core,the expression of the radius of curvature of the unit lead section curve is obtained,and the selection range of the arc radius of the tool tip is determined.According to the length and slope of the cutting edge,a 55° diamond-shaped standard blade with an inscribed circle diameter of 25.4mm is used.Research the generation methods of lateral and longitudinal errors,analyze the curve of lateral error with the diameter of cutter head and the expression of longitudinal error when the lead is 100 mm.Preferably,the diameter of cutter head is 315 mm to realize the machining of screw pump stator core.Using numerical control simulation processing technology to simulate the processing of the stator core,the feasibility of milling by the disc milling cutter was verified according to whether the overcut and residual height occurred;the dynamic process of the milling process of the disc milling cutter was simulated by the finite element analysis software.Under the condition of 300r/min,according to the magnitude and fluctuation of the reaction force,the preferred rake angle value is 8° and the relief angle value is 15°;at the same time,the modal analysis of the cutter head of the disc milling cutter is carried out,and according to the modal analysis results,The optimization direction of the cutter head is proposed.