Development Of Running In Test Bench With Load For Disc Hob Of Tunnel Boring Machine

The tunnel boring machine mainly uses disc cutters for rock crushing,in order to ensure the quality and service life of the hobs.so it is urgent to develop a disc-shaped disc cutter running test bench that meets the actual working conditions,and ensure the performance of the factory disc-shaped hob through the load-loaded running-in test and improve the service life of the tool.In this thesis,taking the disc hob with load running test bench as the research object,the overall mechanical structure and hydraulic loading system of the test bench are designed by combining theoretical calculation and simulation analysis,and the main elements are as follows:The overall layout scheme and functional requirements of this test bench are put forward,and the running-in test bench is composed of three parts: mechanical structure,hydraulic system and electrical control system,in order to meet the strength and stiffness requirements of the test bench,the design optimization and finite element simulation analysis of the test bench hob limit structure,guide structure and friction transmission structure are carried out.The hydraulic loading system of the disc hob running test bench was developed,and the mathematical model of the hydraulic system of the test bench was established based on the modeling method of transfer function analysis,and the working process of the hydraulic system of the running-in test bench was simulated by AMESim simulation software,in order to ensure that the hydraulic loading system has sufficient stability reserves and rapid response,the dynamic performance of the hydraulic system was studied from the perspective of time domain and frequency domain.The results show that the amplitude margin of the open-loop frequency characteristics of the system is 15.2 d B and the phase angle margin is 45.7°,and the system has sufficient stability reserves and rapid response.The test bench adopts the running-in mode of on-load friction transmission,and the life of the friction wheel will be affected under the action of mechanical cyclic stress and thermal stress,and the life of the friction wheel is the key to the running-in test.Based on Ansys Workbench finite element software,the friction wheel and hob contact model was established,and the instantaneous temperature field,contact stress,contact friction stress and overall service life of the friction wheel in the contact zone of the friction wheel and the knife ring were analyzed by direct coupling method.The results show that under the high-cycle fatigue cycle,the theoretical calculated life of the friction wheel is 135,000 times,and the structure is not damaged.Debug the electrical control system of the running-in test bench to ensure that the electrical control system of the test bench meets the predetermined requirements.Install temperature sensors,pressure sensors and photoelectric sensors,and conduct sensor performance tests to ensure the accuracy and stability of sensor measurement results.The influence of hobs on hob torque and temperature under different loads and different speeds is studied.The test results show that the torque of the hob increases with the increase of the load force,and the temperature of the hob increases with the increase of the running-in speed,but the temperature rise is small,and there is no serious heating phenomenon.