Design And Manufacture Of 7LZ172 Metallic Displacement Positive Motor

Positive displacement motors(PDM),as a certain kind of downhole motors,have been widely used in drilling procedures and proved efficacious.Nevertheless,as the drilling depths as well as temperatures keep increasing,motors' thermotolerant ability has been more and more important.Since conventional stators(which are key components in the PDMs)are made of rubber,and due to the characteristics of rubber,conventional motors are more and more unlikely to meet the requirements of high temperature,corrosion and wear working conditions in deep and ultra-deep drilling procedures.Hence,the design of metallic PDMs(which do not consist of rubber components)is quite significant.In order to design metallic PDMs,this paper first implements analysis on the operating principles and characteristics of them,especially on the curve types of the motors that are critical for the motors to achieve their normal functions,and chooses the normal hypocycloid as the curve that used in the design of 7LZ172 metallic PDM,then calculates essential parameters of the motor.Changes the conventional interference fit between rotors and stators into clearance fit,then completes the design of 7LZ172 metallic PDM and establishes 3D models of the motors under different clearances using Creo Parametric.According to the analysis on the operating principles and characteristics of motors,chooses the pressure drop as the target parameter,and implements CFD analysis on the established 3D models of the designed motors with the help of ANSYS Fluent,analyzes the influence of clearances and the characteristics of drilling fluids on the performances of the motors.Selects and uses the electrochemical machining(ECM)as the manufacture technology for the stators of the designed motors,and CNC helical milling for the rotors,and manufactures 2 stators and 3 rotors,then cross matches them to acquire motors of different clearances.Arranges and implements pressure charging experiments in normal temperature on the motors and analyzes the results of the experiments.