Research On Machine Tool Structure And Error Analysis Of Screw Finishing Machining

Because of simple equipment, easy operation, small footprint and high transmissionefficiency, the progressing cavity pump has been widely used in crude production for manyoilfield in China recent years. As a positive displacement pump, the movement of its rotorand stator is under the conditions of the interference fit. The stator usually consists of therubber bushing and steel jacket, the rotor consists of alloy steel which passed by the processof machining and chromium plating. So the rotor is the key instrument of the progressingcavity pump, its surface will influence the life and work efficiency on oil exploration. How toimprove the surface of rotor will be researched in this paper.This paper discussed the method of machining for the rotor at home and abroad, andanalyzed the design of the screw linear method. Three dimensional models for the rotor andstator were obtained by the parameterized design method base on software. Because of theadvantage of belt grinding, belt grinding was chosen as finished machining method. The paperdescribed the removal principle of belt grinding and established removal model, thenanalyzed the pressure which generated in the elastic deformation zone and plastic deformationzone when the workpiece was machining.Innovative machine tool structure for belt grinding finishing rotor surface was proposedin this paper. The machine tool structure includes enclosed belt and forming contact wheel. Inthe process of machining, the rotational movement and axially moving motion move togetherand drive the grinding tools to machine. According to the characteristics between the cross-section of the workpiece and the contact wheel section line, the mathematical expressionswhich transformed in the known conditions of the end face of the cross-sectional shape intoaxial cross-sectional shape and method truncate.Selection of rubber materials as the contact wheel helps to reduce the vibration in theprocessing. The finite element method was used to achieve pure rubber contact wheel,composite steel contact roller and both the force of the contact wheel deformation analysis. The displacement and the pressure change curve relationship were obtained under differentpressure, which provided a theoretical basis for the error analysis.The machine tool structure for belt grinding error which was proposed in this paper wasanalyzed, especially machine geometric errors. A comprehensive mathematical modeling forthe machine tool structure for belt grinding wan established. Through the analysis of basicmotor unit of the machine tool, the unit error expressions were given, which could be used forerror compensation.