Analysis On Excavating Performance Of Gripper And Thrust Mechanism Of TBM

Full face hard rock tunnel boring machine(short for TBM) is the major equipment for tunnel construction of railway, highway, water conservancy, municipal construction and so on, which has the advantages of fast, high quality, environmental protection, safety in relation to the traditional borehole-blasting method and becomes the first selection of the tunnel construction equipment. Gripping-thrusting-regripping mechanism is the core transmission assembly unit to realize continuous cycle operation, which is of great importance to excavating performance. On the basis of systematic analysis of mechanism constitution and working principle, the mechanism topology structure feature is studied. Then, further study of kinematic characteristic is carried out. Statics analysis model is constructed and force of the key components is analyzed. Finally, the virtual prototype simulation of the mechanism is implemented. The main content of the dissertation is as follows:Firstly, topology structure, actuation mode of cylinders and working principle of the gripping-thrusting-regripping mechanism are analyzed systematically. The DOF of different operating condition is calculated. The topology structure feature of mechanism is studied. Equivalent topology structure of different operating condition is built.Secondly, the model of forward displacement analysis and inverse position analysis are established. Then online adjusting(or trajectory correction) motion model is set up. The online adjusting function is deduced, which reveals the mapping rules between the hydraulic cylinder parameters and the main beam pose. On this basis, the correction trajectory is planned.Then, under the premise of reasonable stress assumption in components, the statics analysis model of shield is constructed. The influence rule of force in shield impacting on force in saddle, torque cylinder and gripper is studied. Establishing statics analysis model of gripping-thrusting-regripping system, force characteristics of main beam, guide rail, saddle and gripper are analyzed, which reveal the mapping rules between force of driving hydraulic cylinder and external load on cutter head.In the end, the CAD model is built and assembled using commercial software of Solidworks. The rationality of the mechanism motion is verified by motion simulation. Stress simulation is conducted used the finite method. The force of the key components is analyzed, which provides certain reference for the design of the physical prototype.