| The stump grinding plays a great role in the development of fast-growing plantation and landscaping in our country. The main task in this period is the localization of stump grinder. Cutting shaft and cogged V-belt are key parts of stump grinder’s drive system. Cutting shaft is a kind of part with a flange. Welding processing method is better than turning for its lower cost and higher processing efficiency. The influence of welding on cutting shaft’s modal parameters is unknown and it may make the dynamical performance worse. The cogged V-belt of stump grinder is a transmission of great distance and high speed. The belt vibrates violently while working, which makes the transmission instability. The tooth profile and belt speed have effects on the vibration and stress of belt drive, but there’s still no research about the tooth profile and speed of cogged V-belt. By using numerical simulation and experimental method, the influence of welding on modal parameters and that of tooth profile and belt speed on vibration and stress were studied. The main research content are as follows:(1)After measuring the load of cutting shaft, static and transient analysis were done in Workbench software. The maximum stress was 155MPa and 2262MPa. By using unit birth and death method, welding simulation and modal analysis of cutting shaft were done in ANSYS software. After comparing the welding shaft, turning shaft and heat treated shaft, it was found that in a specific welding condition, the former 10 ordered natural frequencies rised by 13.02%. The result of modal parameters measurement showed that the former 10 ordered natural frequencies rised by 9.04%.(2)The rigid-flexible coupling simulation of trapezoid, circular, triangular cogged V-belt and conventional V-belt were done in MBD (Multi-Body Dynamics) software Recurdyn. At a speed of 700r/min and 2800r/min, the maximum bending stress of trapezoid, circular, triangular cogged V-belt were 78 N/mm2 and 115 N/mm2,98 N/mm2 and 148 N/mm2 and 400 N/mm2 and 136 N/mm2. The stress of conventional V belt is 85 N/mm2 at 700r/min. For trapezoid, circular cogged V-belt and conventional V-belt, the vibration was significant when the machine started. While the triangular V-belt vibrated severely all the time. The vibration at the speed of 2800r/min was more violent than that of 700r/min and the triangular cogged V-belt vibrated more violently while machine starting. For trapezoid cogged V-belt, the maximal lateral displacement and stress increased with the belt speeds.The results of static and transient analysis indicate that the foreign matter (metal, stone) around stump should be cleaned before grinding stump. The machine should stop when it encounters foreign matter. The results of welding simulation, modal analysis and modal parameters measurement shows that in a specific welding condition, a welding cutting shaft has a better dynamics performance and lower processing cost than turning shaft. The results of cogged V-belt rigid-flexible coupling simulation indicates that the trapezoid cogged V-belt is better than the other three kinds of belt and should be preferred while choosing and designing the belt. To reduce the lateral vibration and extend the working life of belt, the stump grinder should be working at a low speed whing grinding stump. |
