Figure 1 shows the spur gear processed by the through continuous “cold extrusion + cold shaping” composite forming process. The vernier caliper is used for rough measurement. The minimum diameters of the upper and lower tooth tops are 74.40mm and 73.86mm respectively, which meet the requirements of the subsequent outer circle. The lower end face is about 2mm convex and the upper end face is about 2mm concave.
3906 spur gear measuring center is used to measure the experimental spur gear. The detection equipment is shown in Figure 2. Five formed spur gears are randomly selected for testing. The total tooth profile deviation and total helix deviation of the left and right tooth surfaces of the four teeth selected at the approximate quartering position along the circumference of the spur gear are tested, and the mean value of the test data is calculated. The average total tooth profile deviation is 12.2 μ m. The accuracy of tooth profile is grade 6, and the total deviation of average helix is 24.2 μ m. The accuracy of tooth direction is grade 8.
Fig. 3 is the inspection report of tooth profile and tooth direction of compound formed spur gear. The measurement results show that the maximum total deviation of tooth profile is 12.2 μ m. The tooth profile accuracy grade of GB / t10095 is grade 6; The maximum total deviation of helix is 26.6 μ m. It has reached grade 8 of GB / t10095 tooth direction accuracy. Through continuous “cold extrusion + cold shaping” compound forming process can be used to process and produce large modulus spur gear for truck with accuracy of Grade 8.
After turning two end faces, boring inner holes, turning outer circles and chamfering, the compound formed spur gear has full tooth shape and good tooth surface quality, as shown in Figure 4.
