5Lange K.Some aspects of the development of cold forging tohigh-tech precision technology[J]. Journal of Material ProcessingTechnology,1992,35 : 245-257.
6Y.K.Lee,S.R.Lee,C.Hlee,D.Y.Yang.Process modification of bev-el gear forging using three -dimensinal finite element analysis[J].Joumal of Material Processing Technology, 2001,113: 59-63.
7K Kondo, K Ohga.Precision cold die forging of a ring gear bydivided flow method [J]. International Journal of Machine Toolsand Manufacture, 1995,35(8): 1105-1113.
8Jongung Choi,Hae -Yong Cho,Jaechan Choi.Upper BoundAnalysis for Forging of Trochoidal Gears.Journal of MaterialsProcessing Technology ,2000,103(3 ) :347-352.