Research On Optimization Design Of Key Structure Of Directional Traversing Power Drilling Tools

With the transformation of national economic growth mode,the main emphasis of economic has been transferred.Pipeline construction and renovation is focused in the future.Among them,the large diameter(580-1016mm)pipeline crossing in hard rock often encountered.Horizontal directional drilling technology is considered as a priority since its high construction quality,short construction time,less personnel requirements and environmental pollution.However,traditional horizontal directional crossing technique is not suitable for large diameter,long-distance cross since there are many problems,for example,crossing length is limited because it is poor in drill pipe stress,control direction ability and drilling stability.The best way to solve the problem is to use power reaming technology,which uses the power drill directly connected to reamer.Power reaming drill is the most difficult and critical in power reaming technology.The output torque of the drill should reach 30kN· m,speed should less than 60rpm based on the process requirement.In accordance with the drilling design theory,the designed power drill is long,heavy,exceeding the company’s manufacturing capacity,poor in trafficability,difficult in service condition,limited in scope of application,which lead to the promotion of the implementation technology is difficult to obtain.In order to solve these problems,it is need to develop a power drill that is short,large output torque and easy to use.This paper carried out the following work.1.Take an analysis on horizontal directional crossing process in references from typical crossing projects.Determine reasonable parameters after measuring the work capacity of the equipment.2.According to the characteristics of the process,design different specifications of the screw drill based on the classical theory.Optimize parameters of moters assembly in order to further reduce the weight and length of the drill.3.In addition to the rubber stator,a great influence on tool life is universal shaft assembly.The ball-type cardan shaft is used in this article rather than the petals-type cardan which is heavy and easy to collision with shell.But it comes to the conclusion after stress analysis that crush deformation may occur in the axial and torsional loads at impact.Therefore,the cylinder ellipsoid ball cardan shaft assembly is designed to resolve the problem that frequent starts and stops.4.The bearings tend to sustain a large push or pull force when it works in drilling,back dragging and stuck freeing.It is concluded for bearing stress analysis that the bearing is limited in axial tension.Then change bearing with cross-cylindrical roller bearings in place of previous.Rearsh on different load of cross-cylindrical roller bearings to verify its reliability and safety.This improvement shorten the length of the power drill.5.On the basis of buttress thread type and short teeth Eyck female thread,the thread parameters were optimized in order to ensure the safety,since the newly developed 0343mm power drill has large output torque,withstand high drag force.(?)343mm power drill is designed based on the horizontal directional drilling technology.This power drill is short,light,low speed,high torque,easy to use,flexible in operation.It has a certain significance for domestic horizontal directional power reaming technology.