Research And Design Of Single Screw Drilling Tool Based On New Molded Lines

With the unprecedented increase in demand for oil products at home and abroad as well as the rapid development of oil drilling industry,single screw drilling tools have gradually replaced other types of down hole power drilling tools,and became the down hole power drilling tools that people use most in the process of oil drilling today.Because of its low manufacture cost,less difficulty,high performance in screw-liner pair meshing,long service life and convenient molded line analysis,single screw drilling tools using new molded lines gradually draw the attentions of the relevant researchers.There are in-depth studies in some poblems such as high manufacture difficulty as well as lower service life caused by poor meshing performance of conventional cycloid single screw drilling tools in this paper and according to the results of the study,a set of single screw drilling tools using new molded lines which have convenient manufacture process,advanced meshing properties and long service life are designed.The design and the structural parameters optimization method of the most frequently used outer equidistant molded lines of curtate hypocycloid are elaborated firstly and the selection and calculation of the structure parameter of screw-liner pair are completed,providing certain theory reference and comparison basis for the follow-up design and research of new molded lines and single screw motor using new molded lines.This paper mainly completed the design and research of new molded lines of single screw motor.First of all,through the establishment of mathematical model of original tooth profile curve,the equations of original tooth profile curve are deduced.And then,the equations of conjugate tooth profile of new molded curve and the equations of flow areas of screw-liner pair of new molded lines are deduced with inner roll method and normal method.The change rule of curvature of new molded lines is analyzed.The optimal curvature K~*of screw-liner pair using new molded lines is defined.Seven independent structure parameters of screw-liner pair using new molded lines are defined.The contrast analyses of independent structure parameters,flow area and the curvature of new molded lines and outer equidistant molded lines of curtate hypocycloid are completed.The whole structure design of single screw drilling tools using new molded lines is completed.Single screw drilling tools include bypass-valve assy,drop-proof assy,single screw motor assy using new molded lines,cardan shaft assy and transmission shaft assy.The calculation of structure parameters of single screw drilling tools using new molded lines,the model selection of cardan shaft assy and the calculation of the biggest change Angle are completed.The structure design scheme of each assy is completed and the design drawings of key parts of each assy are gave.The strength check and reliability analysis of the transmission shaft assy and the strength check and fatigue life calculation of the cardan shaft assy are completed.