Dongfanghong tractors produced by Luoyang No.1 tractor manufacturing plant of China are very important traction equipment for farming, harvesting and transportation, as shown in Figure 1. In heavy tractor parts, worm is the most commonly used parts, its quality will affect the performance of the tractor.
The worm gear mechanism in the gearbox of Dongfanghong tractor is the most common component. The gear model can be created by Pro / E. There are two ways to create the model: one is direct modeling, the other is parametric modeling. The parametric modeling method is based on the direct modeling method. By recording the modeling steps, you can refer to the modeling process of the first one when creating the second one, and directly input the dimension parameters to create a new part.
When modeling the helical gear (see Figure 2), we first establish a two-dimensional sketch, then complete the preliminary model through a series of operations such as stretching, scanning and cutting, and modify the gear model according to some details of the gear and the fit with the worm. In the process of gear modeling, steps can be saved to design parameter modeling software. For example, by combining with VB software and developing parametric modeling software, new helical gears can be generated by inputting parameters.
The modeling of worm is similar to that of helical gear, as shown in Figure 3. After the basic model is established, the established worm feature is rotated and excised to obtain the complete worm feature. During the simulation, the appropriate position can be selected according to the parameters needed in gear optimization, and the simulation parameters can be output.
Select the items to be measured, select the measurement position or axis according to the requirements, click apply and confirm, and then select the items to be output (such as speed, acceleration or displacement). This time, the maximum torque is selected to check the gear system.
Figure 4 shows the curve obtained by ADMAS software through simulation calculation. According to the curve, the maximum torque in motion can be obtained. In the design of gear system, the device can be checked according to the maximum torque to check whether the mechanical load is within the allowable range, so as to achieve the purpose of parts optimization.
