Gear is a kind of mechanical element with continuous meshing transmission of motion and power on the rim, which plays a key role in mechanical appliances. Under normal working condition, gear can realize transmission and other functions. Gear transmission device is the most widely used and stable mechanism and transmission device at present. At the same time, gear is also the core component of many mechanical products. However, due to the high intensity of mechanical production and other related factors, mechanical gears often fail, leading to mechanical paralysis and other problems, reducing the production efficiency of mining enterprises, leading to the occurrence of safety accidents, which must be improved. Therefore, it is of great significance to understand the failure forms of gears, analyze the failure causes of gears, study the control methods of mechanical gear cracking, and put forward specific control methods, so as to improve the fatigue strength of gears, mechanical life and increase the production efficiency of enterprises.
For the problem of mechanical low-speed and heavy-duty gear cracking failure, the material selection and design of mechanical low-speed and heavy-duty gear are optimized
① At first, the cracking and spalling propagate along the crack on both sides. The cracked area is squeezed and worn in the process of meshing. In many cycles, the crack propagates rapidly, and finally the gear cracks and spalls.
② In the process of cracking, plastic deformation has been formed between the two cracked surfaces due to mutual extrusion. Because the cracked surface has been squeezed and worn for a long time, the cracked grain surface has been ground flat in the cracking process, which indicates that the cracked surface has been squeezed and worn for a long time in the cracking process.
③ Through the comparison of machinability, forgeability, wear resistance, hardenability and overload resistance, the Ni Cr Mo steel with better performance in all aspects should be selected.
④ The heat treatment process of Ni Cr Mo steel with hard tooth surface steel such as chromium steel should be carburized at 930 ℃, quenched at 820 ℃, cooled by 60 ℃ engine oil, and reheated at 180 ℃. The heat treatment process is simpler than that of Ni Cr steel, with shorter production cycle and lower cost. The surface strengthening treatment should be carried out after carburizing or grinding.
⑤ During the gear installation, the flatness, meshing clearance, center moment, parallelism, bearing installation and contact area of the center line of the gear shaft should be considered.