Study On The Normal Force And Rolling Force Prediction Model Of Inserted Tooth Hob

Because of the high efficiency and safety construction,the raise boring machine has been widely used in shaft construction engineering in recent years.For the hob is the critical component that contact with the rock,the force between hob and rock directly affects the construction efficiency in the process of rock-breaking drilling by raise boring machine.It is great significance to the construction worked by raise boring machine of study the rock-breaking force by inserted tooth hob,because inserted tooth hobs are the most used cutters in the raise boring machine.The prediction model of rock-breaking force is established by analyzing the force of single tooth that penetration into the rock and the motion trajectory of inserted tooth hob.The prediction formula of the rockbreaking force is deduced according to the model and verified by simulation.The main research contents and conclusions are as below:(1)Based on the contact theory of the tooth penetration to the rock and rock breaking theory,the force of the contact surface which between the tooth and the rock is analyzed.We can get that the distribution of contact forces can be simplified to uniform distribution and the force direction is perpendicular to the contact surface.(2)According to the structure and the rolling method of the insert tooth hob,the motion trajectory formula of inserted tooth hob is deduced and the trajectory diagram of the center point of hob has been made.(3)By analyzing the contact force of half-side spherical tooth,the calculation formula of rock-breaking force by single tooth is obtained.According to the results of the contact force on half-side spherical tooth and the results of inserted tooth hob motion trajectory,the prediction model of rock-breaking force by inserted tooth hob is established and the rock-breaking force calculation formula is deduced.Make curves and analysis it.(4)Made simulations to the model of single tooth penetration into rock and the model of single row inserted tooth hob penetration into rock,the simulation results are compared with the theoretical results and the correction parameters of the prediction formula is proposed.(5)The model of different kinds of multi-row inserted tooth hob penetration into rock is simulated.We can get that each of the hob will not cause any disturbance to the other hob when the single-row inserted tooth hob is rolled side by side.Therefore,the calculation formula of rock-breaking force can be used to predict the rock-breaking force of multi-row inserted tooth hob.