1. Drawing of tooth profile of non-circular gear
At present, the envelope method and tooth profile folding algorithm are mostly used to solve the non-circular gear, but the tooth profile conversion method has low precision and complex process, so it is used less and less. In this paper, the envelope method is used to design the non-circular gear. This algorithm theory has been very mature, so it will not be detailed here. Referring to other literatures, the envelope of gear shaper tool with standard involute profile forms non-circular gear profile. According to the formula, the driving gear profile generated by envelope is shown in Figure 1. Similarly, the driven gear tooth profile can be generated, which will not be displayed here. Using the method of image processing, the tooth profile points can be extracted quickly, and the non-circular gear graphics can be obtained by importing the tooth profile point data into AutoCAD, as shown in Figure 2. In order to better represent the position and meshing of the two non-circular gears, the meshing diagram of the driving gear and the driven gear is drawn in combination with the rotation center of the non-circular gear obtained in Fig. 3.
2. Non-circular gear assembly
Import the two-dimensional graphics of the obtained non-circular gear into Pro / E, and use the stretching command to stretch the thickness of 40 mm. After stretching, the three-dimensional model of the non-circular gear is obtained. Set a hole with a diameter of 6 mm at the rotation center position obtained in Figure 3 as the installation position, assemble and set constraints in Pro / E software, and set the gear rotation command at the installation center point of driving wheel and driven wheel. After assembly, it is shown in Figure 4.
Set the motor at the rotation center of the driving wheel for rotation. At this time, the driven wheel will rotate with the driving wheel. It is observed that the gear pair has good meshing and stable rotation during the rotation process, meeting the requirements of gear rotation.