Spiral bevel gear has been widely used in aviation, automobile, shipbuilding, engineering machinery and many other industrial fields. Spiral bevel gear can be seen as the straight bevel gear is cut into countless slices and then rotated. The tooth meshing is carried out continuously and smoothly from one end to the other. Because of the increase of the overlap coefficient, the spiral bevel gear runs more smoothly than the straight bevel gear and the zero degree bevel gear, and the bearing capacity is also higher, and the noise and vibration of high-speed operation are significantly reduced. Therefore, the straight bevel gears used in aviation, navigation, automobile, tractor and various precision machine tools have been gradually replaced by spiral bevel gears, and the design and manufacture of spiral bevel gears occupy a very important position in the mechanical industry.
Under the ideal working conditions, the working tooth surfaces of spiral bevel gears should all participate in the work. At the same time, the contact marks of the gear teeth gradually disappear at the top and end of the teeth. In this way, the gear has the maximum bearing capacity, and the operation is the most stable, no noise. But in fact, in all working conditions, this kind of ideal tooth contact is impossible. The design and manufacturing errors of the support and gear must be considered, and the manufacturing and assembly errors limit the effective contact length and width.
With the development of modern industry, the high load and high speed of gear transmission has become the trend of the development of gear industry, and the requirements for the performance of gear transmission are higher and higher. The traditional design and calculation methods can not meet the requirements. In processing and manufacturing, including the adoption of CNC and other advanced technologies, the research on the relationship between the tooth surface contact mark and the bearing capacity in the process of gear meshing has a more and more direct and important role in guiding production.
In the early sixties, it was proposed to use tooth contact analysis to analyze the light load running quality and contact characteristics of spiral bevel gear pair and hypoid gear pair. Since then, it has been improved, considering the edge contact, and has been widely used in gear industry. The premise of the correctness of this analysis method is: gear pair under no load or light load.