Design of new forging die for spiral bevel gear

Part drawing of driven spiral bevel gear

According to the deformation of metal, the precision die forging of spiral bevel gear can be divided into open die forging and closed die forging. Figures 1 and 2 respectively show the part drawing and three-dimensional modeling drawing of driven spiral bevel gear of Chinese automobile. The parameters of spiral bevel gear are shown in the table.

Three dimensional modeling drawing of driven spiral bevel gear parts

It can be seen from figures 1 and 2 that the shape of spiral bevel gear is relatively special, so it is difficult to adopt the die structure used in the usual closed die forging. For a long time, the research on the precision forging of this kind of spiral bevel gear is only limited to open die forging. Because the forging produced by open die forging will inevitably have flash and skin, which increases the cross-sectional area of the forging and increases the forging forming force required for processing, which will not only increase the subsequent processing, waste energy, and even damage the forging die due to excessive stress. Therefore, it is necessary to find a new closed die forging method to form spiral bevel gear. Based on the brief description of the open die forging die structure of spiral bevel gear and its problems in actual production, the new process of precision forging of spiral bevel gear is analyzed, and the new die structure is discussed.

Serial numberNameCodeCompanyCalculation formula and descriptionParameter value
1Number of teethZKnown25
2Large end modulus of tooth profilemmmKnown9
3Tooth profile angleα(°)Known20
4Addendum height coefficienth*αSelect by table0.85
5Top clearance coefficientc*Select by table0.188
6High displacement coefficientxx=-0.39(1-1/u*u)-0.29
7Tangential displacement coefficientSelect by table0
8Helix angle at the midpoint of tooth profileβ(°)Known35
9Spiral directionDextral
10Split cone angleδ(°)Select by table62.5
11Graduation circle diameterdmmd = mz225
12Cone distanceRmmR = d/2sinδ126.801
13Tooth width coefficientφRφR = 1/3.5-1/30.315
14Tooth widthbmmTake b= φR and b = 10m the smaller 40
15Addendum heighthammha = (h*a+x)m5.04
16Full tooth heighthmmh = (2h*a+c*)m16.992
17Root heighthfmmhf = h-ha11.952
18Addendum circle diameterdammda = d+2hacosδ229.6504
19Root angleθf(°)tanθf = hf/R5.385
20Tooth apex angleθa(°)θa2 = θf13.039
21Top cone angleδa(°)δa = δ + θa65.5
22Root cone angleδf(°)Δf = δ – θf57.1
23Cutter head diameterD0mmKnown228.6
Scroll to Top