Heavy duty spiral bevel gear has many excellent characteristics, such as stable transmission performance, low noise, large transmission torque and so on. Therefore, it is widely used in the transmission system of heavy vehicles. At the same time, it meets the requirements of light weight, high bearing capacity, low energy consumption, high reliability and long life of heavy vehicles. Heavy duty spiral bevel gear is a special bevel gear, and its tooth surface pitch line is curve. During the transmission of heavy-duty spiral bevel gear pair, its teeth contact gradually and smoothly from one end to the other end, so the number of teeth engaged at the same time is more than that of spur gear. The helical angle direction of the big teeth and the small teeth of the heavy-duty spiral bevel gear is opposite and the size is the same, so it has a greater degree of coincidence than the straight bevel gear, which is the reason for its low noise and low vibration, as shown in the figure.
However, the design and manufacture of heavy-duty spiral bevel gear is the most complex among all kinds of gears, and the quality control is extremely difficult. Due to domestic heavy-duty spiral bevel gear materials and other reasons, the heavy-duty spiral bevel gear has large deformation after heat treatment. Only by grinding teeth can the deformation error be corrected, the accuracy and strength be improved, and the transmission noise be reduced, Therefore, at present, more than 65% of heavy-duty spiral bevel gears generally adopt the process of “gear milling – heat treatment – gear grinding”.
For the carburizing and grinding process of 30crmnti, 18Cr2Ni4WA and other high-strength alloy steels, the fatigue strength of high alloy high-strength steel is very sensitive to the machined surface defects. In the grinding process, the surface roughness, microcrack, residual stress, microhardness, metamorphic layer depth, metallographic structure and other factors of the gear tooth surface will play a decisive role in the bending fatigue, impact resistance and contact fatigue of the gear tooth root. The formation of residual stress, metamorphic layer depth and other factors often comes from multiple key processes of gear processing, which is cumulative and has considerable complexity.
At present, there is a lack of research on thermal processing and surface integrity in the manufacturing process of heavy-duty spiral bevel gears. There are some problems in the products, such as large heat treatment deformation, grinding cracks or burns on the surface, and excessive roughness of the gear surface affecting the meshing, resulting in low production efficiency and low product qualification rate (< 85%), so it is urgent to carry out the research on the surface integrity of grinding tooth surface, Solve the damage problem in the grinding process of heavy-duty spiral bevel gear and improve the productivity of heavy-duty spiral bevel gear.
According to the machining requirements of typical heavy-duty spiral bevel gears of heavy-duty vehicles in the present and future, the grinding quality of heavy-duty spiral bevel gears can be effectively reduced by carrying out the research on the grinding surface performance of heavy-duty spiral bevel gears, realizing the control of gear surface integrity and the optimal pre control of grinding parameters. Through the improvement and optimization of process parameters, it can not only promote the manufacturing level of the whole heavy-duty spiral bevel gear, but also provide technical support for the research and development of new heavy vehicles.