After the research model of transmission gear transmission mechanism is established, the software is used to set the operating conditions as input speed of 6 000 R / min, torque of 120 n · m and power of 75 kW. The fourth gear is selected for static analysis, transmission error analysis and tooth contact analysis. Gear static analysis can study the strength performance of gear, mainly including contact strength check and bending strength check. Through the static analysis of the gear, the stress of the gear can be checked, and the damage rate and life of the gear can be studied. The stress, damage analysis and safety factor of the fourth gear before modification are listed.

The maximum contact stress of master and slave gears is large, and the safety factor of contact strength is small. In the actual working process, there is the possibility of contact strength fatigue failure, so it is necessary to complete the design optimization, so as to improve the strength.

The vibration and noise of gear is a very important evaluation index. The transmission error of gear has a great influence on the noise of gear. The analysis of transmission error of gear can effectively minimize the meshing deviation of gear and enhance the stability and accuracy of power transmission process. Run the gear transmission error module of the software to analyze the transmission error in the meshing process of the fourth gear. Generally, in order to reduce the noise of the transmission as much as possible, the transmission error should be reduced as much as possible, and the control range should be less than 2 μ M. As shown in Figure 1, the transmission error curve of the fourth gear of the gear transmission mechanism of the front transmission is modified.

It can be seen from Figure 1 that before the modification, the peak transmission error of the fourth gear is 2.30 μ m, and the transmission error of gear motion is too large, which affects the stability of power transmission and does not meet the design requirements, so it needs to be optimized.

When the gear is in meshing motion, the tooth surface load of the gear will have a great impact on the maximum bearing capacity of the gear. A good tooth surface load distribution can improve the maximum load that the gear can bear, avoid the damage of tooth strength caused by stress concentration, improve the load bearing capacity of the gear, and improve the working life of the gear. Using the software to analyze, the load of unit meshing length on the tooth surface of the 4th gear before modification can be obtained, as shown in Figure 2.

In Figure 2, it can be found that the load distribution on the tooth surface of the 4th gear is uneven, resulting in serious load stress bias, and the maximum load per unit meshing length is 376 MPa. Due to the influence of gear deformation and assembly accuracy in the process of power transmission, the phenomenon of eccentric load occurs in the process of gear movement. Therefore, it is necessary to use gear three-dimensional modification technology for optimization.

When the gear is in meshing motion, the tooth surface load of the gear will have a great impact on the maximum bearing capacity of the gear. A good tooth surface load distribution can improve the maximum load that the gear can bear, avoid the damage of tooth strength caused by stress concentration, improve the load bearing capacity of the gear, and improve the working life of the gear. Using the software to analyze, the load of unit meshing length on the tooth surface of the 4th gear before modification can be obtained, as shown in Figure 2.

In Figure 2, it can be found that the load distribution on the tooth surface of the 4th gear is uneven, resulting in serious load stress bias, and the maximum load per unit meshing length is 376 MPa. Due to the influence of gear deformation and assembly accuracy in the process of power transmission, the phenomenon of eccentric load occurs in the process of gear movement. Therefore, it is necessary to use gear three-dimensional modification technology for optimization.