Japanese scholars K Kondo and K ohga proposed the gear split flow forging method and applied it to spur gears. At the same time, their applicability in the precision forging of ring gears was studied. By artificially setting the shunting hole in the return, the return material is filled in the die cavity with the reduction of the shunting hole, so that the precision forgings can be obtained under low forming force. Luoshanming et al. Put forward a new process of closed pre forging and split flow final forging for spiral bevel gears on the basis of split flow forging. J. C.choi put forward the process of gear precision forging inward split forming, further developed the split method, carried out finite element simulation analysis, and applied this technology to the forging of spur gears.
Jidongsheng studied the forming mechanism of hollow split flow forging, established an optimization model with the minimum forming force as the objective function, and combined the two to complete the structural design of the die for hollow split flow forging forming spur gear. The forging has good forming quality and improves the die life.
Liuhuawei et al. Analyzed the precision forging process of spur bevel gear, formulated the key points of process design including forging drawing design, gross dimension selection and precision forging deformation force determination, discussed the structure and working process of precision forging die, defined the factors affecting die life, and put forward the problems that should be paid attention to in the use of die.
Wangchunfen studied the phenomenon of tooth fracture of conical gear made of 20Cr2Ni4A steel during use. By analyzing chemical composition, mechanical properties, metallography, fracture analysis and 3D video microscopic imaging, it was found that the tooth fracture belongs to fatigue fracture. The reason is that the gear forging is poor and the inappropriate forging ratio is selected, As a result, the mechanical properties of the residual cast structure were reduced, and the root machining tool marks were too deep, resulting in stress concentration.
Zhang Chi et al. Studied the development of block forging at home and abroad, and found that a large number of bevel gears were produced by this process in foreign countries in the s of the last century. The bevel gears produced by this process have high precision and long service life of the forging die.