Design Of The Measuring System For The Internal Profile Of The Screw Drill Stator

As the core component of the screw drilling tool motor assembly,the accuracy of the inner contour of the screw drilling tool stator affects the performance of the screw drilling tools.By using the traditional non-centering inspection method of mandrels,it is possible to determine whether the inner diameter dimensions of the screw drilling tool stator meet the machining quality,but no quantitative conclusions can be drawn;The internal spiral surface measuring machine can not only measure the workpiece contour but also determine whether the stator inner diameter size is within the control range.However,due to its large size constrained by space,it is also unable to complete the inspection of longer workpieces.Therefore,this paper investigates the screw drilling tool stator section internal contour measurement system by using automatic centering technology,aiming to design a portable and efficient measurement system to realize the inspection of the machining quality of the screw drilling tool stator.Firstly,the requirements of the measurement system based on the main characteristics of the inner surface of the screw drilling tool stator and determines the technical indexe of the measurement system by combining the processing accuracy and inspection technology of the screw drilling tool stator was analyzed.Moreover,the measuring principle of the measuring system,designs the overall scheme of the screw drilling tool stator section internal profile measuring system,and introduces the selection method of angle and distance sensors were provided.Secondly,this paper investigates the mechanical relationship of the measurement system and determines the conditions for reliable contact of the centering mechanism and the critical value of the maximum contact force that can complete the movement of the measurement system in the inner cavity of the stator by using the method of hydrostatic analysis for gravity and friction of the measurement system.On this basis,the contact force is determined,and the relationship between the working load of the spring and the angle is obtained by converting it to the horizontal direction.In order to achieve adaptive adjustment,spring design is carried out to solve the relationship between the spring compression and the diameter of the substrate to be measured.Thirdly,the structure of the centering mechanism is studied in this paper,and the support structure of the centering mechanism is designed by using the parallelogram mechanism to realize the functions of supporting the measurement system and the centering mechanism up and down.By designing the drive-centering structure,the control of the sensor rotation and the movement of the measuring device are realized,which keeps the measuring system in the stator center position and provides the reference for the sensor to implement the measurement.In order to enable the adjustment of the measurement range,the pressure adjustment device is designed in this study,and the design of the engineering prototype of the measurement system is completed using the connection structure.Finally,a prototype screw drilling tool stator cross-section measurement system was built,and the radial circular runout of the mandrel was obtained by the measurement system centering mechanism mandrel circular runout detection experiment,and the eccentricity of the mandrel was obtained by the least squares fitted circle method.On this basis,measurement experiments of precision experimental cylinders are conducted to calibrate the measurement system adjustment device.The results show that the radial circular runout of the centering mechanism studied in this paper is 5.50 μm,the eccentricity is 1.56 μm,the extended uncertainty of the measurement system is 2.70 μm,and the measurement error of the screw drilling tool stator measurement system is less than 6.57 μm.This meets the requirements for the accuracy of screw drilling tool stator inspection.