For gear and shaft parts, the material selection and structure design is very strict due to the function of transmission power. In order to improve the bearing capacity, gear and shaft are generally made of alloy steel. External gears are recommended to use materials such as 20CrMnMo, 17Cr2Ni2A, 20CrNi2MoA, 17CrNiMo6 and 17Cr2Ni2MoA. 42CrMoA, A and other materials are recommended for inner gear ring and shaft parts. The forging method is used to make the blank, which can obtain good forging tissue fibers and corresponding mechanical characteristics. Reasonable preheating treatment and intermediate and final heat treatment process ensure that the integrated mechanical properties of materials meet the design requirements.
The precision of the main driving gear in the gearbox is not less than 6 GB/T10095 and the inner gear is not less than 6 GB/T10095. Generally, the final heat treatment method is carburized and hardened. The surface hardness of the tooth reaches HRC60+/-2, and it has good anti-wear contact strength. The core of the tooth has relatively low hardness and good toughness, which can improve the bending strength.
When processing herringbone teeth, if the overall structure, there should be a fall-off groove between the half herringbone gear; In the case of assembling the herringbone gear, the two halves of the gear are respectively processed according to the ordinary cylindrical gear, and finally the two are accurately aligned with the teeth, and then through interference fit on the shaft.
In gear machining, it is very important to specify the process standard. When machining the shaft gear, the center hole of the end of the two shafts is usually installed on the machine tool. Cylindrical gears are positioned on the machine tool by means of internal holes and an end face as the process reference.
In a pair of gear pairs, the tooth width of the pinion is slightly larger than that of the pinion, mainly to compensate for axial size changes and ease of installation. In order to reduce the load inhomogeneity caused by axial deflection and elastic deformation in transmission, the gear teeth should be modified during tooth shaping.