Spiral bevel gear plays an important role in transmission machinery. However, its tooth surface shape, transmission characteristics, the structure of machining machine tool and machining adjustment are more complex. Spiral bevel gear transmission has become the key technology and commanding point of gear transmission, and has always been the focus of gear experts and scholars at home and abroad. The key to analyze the gear meshing is to reveal the meshing transmission mechanism of the gear pair and fully understand the influence of various parameters in the gear pair on its meshing performance. The strength of spiral bevel gears directly affects the performance of the whole mechanical equipment. Its transmission accuracy, mechanical efficiency and bearing capacity will directly affect the working life, vibration and noise of gear teeth. Experts and scholars in the field of gears all over the world have been engaged in the research of spiral bevel gears.
The concept of spiral bevel gear was first put forward by Gleason company of the United States. The company not only created the geometric relationship of spiral bevel gear transmission, but also accurately analyzed and studied its tooth surface geometry. When working, the gear needs to have sufficient strength, stability, large service life and other excellent properties to make it safe and reliable in the working state. In order to meet such requirements, the strength calculation must be carried out according to the load size and basic dimensional parameters in the design process. The strength checking calculation of spiral bevel gear mainly includes the calculation of tooth surface contact strength and the calculation of tooth root bending strength. In order to check the bending and contact strength of gears, the gear teeth are traditionally completed as a cantilever beam. The calculation of this method is more complex, and it is prone to errors or even errors. The verification cycle is long, the difficulty is large, and the accuracy is not high. Spiral bevel gear reducer usually works under dynamic load, which will lead to a great difference between the actual force of gear teeth and the static load of ideal beam. This method can not reflect the overall deformation and stress of the structure, and it is difficult to guide the design of spiral bevel gear.
If the design parameters of spiral bevel gear change, the drawing needs to be redesigned. Obviously, the efficiency of this design method is relatively low, and it is difficult to design spiral bevel gear products with ideal quality. Since the 1970s, China’s Zheng Changqi, Zeng Tao, Wu Xutang and other experts and scholars have carried out various research work on the calculation card, calculation program and tooth surface contact program of spiral bevel gear design and processing, analyzed its compilation principle and deduced a variety of calculation formulas.
At the same time, these experts and scholars in spiral bevel gear also put forward the calculation principle of load contact analysis of spiral bevel gear. In 1998, Fang Zongde simplified the contact under load as a contact line along the long axis of the instantaneous contact ellipse. In the 1980s, the contact strength of spiral bevel gears was obtained by the calculation method of Hertz theory, but the theory could not accurately determine the deformation on the tooth surface, the load distribution in each contact area and the load distribution of simultaneous meshing teeth. This method is only an approximate method. In fact, when meshing, the gear teeth have a long tooth direction contact area, a short tooth height contact area, and the rigidity of the gear teeth is relatively large. The classical elastic contact theory can not give a good analytical expression. Moreover, this theory is only applicable to some semi infinite objects with simple shape or some symmetrical bodies with simple shape. With Gleason’s increasing ability to design and produce spiral bevel gears, the company has gradually formed a complete set of technology on spiral bevel gears. Internationally, Gleason has become a leading enterprise in the spiral bevel gear manufacturing industry.