Design And Optimization Of The Cardan Shaft Structure Of New Type Screw Drill

The universal shaft of screw drilling tool is one of the most vulnerable components in the screw drill.With the normalization and diversification of the screw drilling tools used in the drilling engineering,the failure of the universal shaft has become a problem to be solved urgently.There are natural defects in the traditional universal shaft because of its structural form or scope of application.It is difficult to obtain good application effect in the complicated downhole conditions,which limits the further development of the service life and work stability of the screw drill.In this paper,the principle of double cross universal transmission and the characteristics of the universal shaft drive of the screw drill are analyzed.A new type of universal shaft with the structural advantage is designed for the defects of the traditional universal shaft.Through the dynamic analysis of the universal shaft of the screw drilling tool,a key link of the design of the new spherical tooth insert universal shaft is given.Based on the working parameters of the universal shaft of the 7LZ172 type screw drill,the structure interference,the strength and the stress state of the cardan shaft are analyzed by the method of numerical calculation and dynamic simulation,and the optimal structural parameters of the key components of the embedded universal shaft are determined.Starting from the stagnation state and normal working state of the screw drill,the static stress simulation under static load and the stress simulation in the motion process are simulated with the optimal structure of the universal shaft as the model.The safety hysteresis torque of the new type 172 type screw drilling tool under the axial force of 100 kN is 11.67kN·m,and the safe working torque is 5.764kN·m.The application of this universal shaft in screw drilling tools has good prospects.