Manufacturing technology of curved bevel gear for automobile drive axle

At present, there are two kinds of gear systems in China, Gleason system and Oricon system. The tooth line made by Gleason is circular arc or approximate circular arc, and the tooth shape contraction mode is gradual reduction, commonly known as spiral bevel gear or gradual reduction bevel gear. The tooth line made by orikon is an extended epicycloid, and the tooth shape is equal height, so it is called extended epicycloid bevel gear or equal height bevel gear. No matter what kind of bevel gear, if the active and passive axis is offset, it is also called hypoid gear or hyperbolic gear. It has been suggested that Gleason bevel gear and Oricon bevel gear are collectively referred to as spiral bevel gear. The author believes that it is inappropriate that only “curved bevel gear” can include Gleason bevel gear and Oricon bevel gear. Of course, curved bevel gear also includes Klinger bevel gear, but this bevel gear is rarely used in automobile drive axle. Modern automobile drive axle requires curved bevel gear to have higher bearing capacity and better ride comfort. China produces nearly 20 million sets of curved bevel gears every year, most of which are spiral bevel gears (including accessories), which is the largest manufacturing country in the world. However, at present, most enterprises in the domestic gear industry have backward manufacturing equipment and process level, weak quality awareness, overcapacity of medium and low-end products, increasingly fierce market competition and declining profit margin. The production capacity of high-end products is insufficient, most of them still rely on imports, and the export volume is very small.

The products of large and medium-sized manufacturing enterprises of curved bevel gear of automobile drive axle in China are mainly matched with automobile drive axle. The products produced by small manufacturing enterprises are mainly supplied to the accessories market, and some products are also supplied to special-purpose vehicle drive axle. The product division of automobile drive axle curved bevel gear manufacturing enterprises is clear, and their respective supply channels are formed according to micro automobile drive axle, medium and light automobile drive axle and heavy automobile drive axle. The gears matched with the drive axle of micro vehicles are mainly Wuling series and Chang’an series. The drive axle of medium and light vehicles is mainly matched with Isuzu series, BAIC series, JAC series, overbearing series, Ruifeng series, Harvard series, cheetah series, golden cup bread series, etc. the drive axle of heavy vehicles is mainly matched with 153 series, 457 series, Steyr series, beiben series Man series, 460, 485, 498 series and other products. Automobile drive axle spiral bevel gear manufacturing enterprises used to be mainly distributed around automobile and axle manufacturing enterprises, but in recent years, there have been two new development trends, namely industrial agglomeration effect and downward extension of group industrial chain. For example, in Shandong, there are more than 20 heavy truck drive axle gear manufacturing enterprises, and about 10 with an annual output of 200000 sets of gears. In recent years, in order to obtain high-quality curved bevel gears, many automobile groups and axle manufacturing enterprises have spared no expense in importing advanced manufacturing equipment to produce bevel gears by themselves, such as qingte group, Liaoning Shuguang, Jinan Heavy Truck Group, etc.

Face milling Face hobbing

The processing technology of curved bevel gear of automobile drive axle is mainly divided into two categories: face milling and face hobbing. As shown in Figure 1, there are two corresponding tooth systems: Gleason system and Oricon system. At present, orikon has merged with klinberg company of Germany and mastered the complete set of processing technology of equal height bevel gear. In the 21st century, Gleason company of the United States has also developed its own system of end face hobbing technology for machining equal high tooth bevel gears. The Phoenix second generation gear milling machine developed by Gleason company can not only use end face milling method to process tapered teeth, but also use end face hobbing method to process equal high teeth.

China began to tackle the key problems of the complete set of theory and processing technology of Gleason spiral bevel gears in 1973. After more than 40 years of development, a series of research results have been obtained. In the aspect of tooth surface design and simulation analysis, this paper makes an in-depth theoretical research on the tooth surface design, tooth surface contact analysis, tooth surface NC machining, tooth surface error detection and correction of spiral bevel gear, and develops the spiral bevel gear design calculation and tooth surface analysis software suitable for China’s national conditions. In terms of tool manufacturing, Harbin first tool factory, Harbin tool factory and other enterprises have owned the R & D technology and production capacity of Gleason tools. In terms of NC machining, Tianjin First Machine Tool General Factory, Tianjin Jingcheng Machine Tool Co., Ltd. and Luoyang Keda Yuege NC Machine Tool Co., Ltd. developed spiral bevel gear NC milling machines and put them on the market in batches; The CNC gear grinding machine for spiral bevel gears developed by Zhongda Chuangyuan and hallang kaishuai has also been applied in the domestic market. In terms of tooth surface error detection, Harbin quantity group and Harbin Jingda company have developed a gear measurement center, which can detect the tooth surface error of spiral bevel gear.

Relatively speaking, the research on Oricon bevel gear technology in China is still in its infancy. Compared with Gleason spiral bevel gear, Oricon bevel gear has the advantages of high processing efficiency, strong bearing capacity and low noise. Therefore, it is more and more favored by gear users. This gear system has attracted great attention of domestic axle manufacturing enterprises and gear processing enterprises in recent years. In foreign countries, it has become a technical trend to use the end face hobbing method to process equal high tooth bevel gears. For example, dozens of “five knife method” production lines originally used by Volkswagen have been changed to “two knife method” to process equal high teeth; In 2007, American axle company completely eliminated tapered teeth and adopted equal height teeth; Rockwell, the largest axle company in the United States, also uses equal height teeth in all its new plants; Famous automobile companies such as Ford, GM, Toyota and Honda also began to process high tooth bevel gears; Gleason company, which has been using the end face milling method to process bevel gears, also began to vigorously develop the end face hobbing technology. Therefore, two tooth systems will coexist in the future, and the share of equal height bevel gear in the market will gradually expand.

Facing this market situation, domestic gear manufacturing enterprises also began to invest in the construction of equal high tooth bevel gear processing production line in order to obtain market share. However, due to historical reasons and the limitation of manufacturing equipment, the technical research of equal high tooth bevel gear in China is relatively backward. At present, it is still in the initial stage in tooth surface design, tool R & D, machine tool manufacturing and tooth surface detection and correction. Although the face hobbing technology of equal height bevel gear has developed mature abroad and realized the digital closed-loop manufacturing technology, this technology is still monopolized by klinberg company in Germany and Gleason company in the United States. The two companies keep the end face hobbing technology of bevel gears confidential and do not disclose any relevant technical data. Therefore, for China, this technology is like a black box, which still puzzles relevant enterprises and technicians.

In order to have the production capacity to process high tooth bevel gears, some large and medium-sized domestic enterprises, such as FAW Group, Zhuzhou gear, Jinan heavy truck, Dongfeng axle, qingtezhongli, Shuguang group, Jiangsu Shuanghuan, Zhengzhou Huawei and Shaoguan Hongda, imported Oricon C series CNC gear milling machine and Gleason Phoenix second-generation CNC gear milling machine, as well as gear milling cutter head and CNC grinding machine Knife bar detector, cutter loader, gear measuring center and other equipment, the whole set of equipment costs tens of millions, and the high price is beyond the reach of most small and medium-sized enterprises in China. Therefore, it is not realistic to rely on a large number of imported equipment to improve the processing capacity of equal height bevel gears in China, and what we introduce is only equipment, and we can not really master the processing technology of equal height bevel gears. The lack of this processing technology not only increases the gap between China and the international advanced manufacturing technology of curved bevel gear of automobile drive axle, hinders the development of bevel gear technology in China, but also makes us lose our competitiveness in the international automobile drive axle gear market. Therefore, it is an urgent task for us to study the face hobbing technology of equal high tooth bevel gear and realize the localization of manufacturing equipment.

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