3D FEM simulation of flow velocity field for 5052 aluminum alloy multi-row sprocket in cold semi-precision forging process

Based on the design of the multi-row sprocket with a new tooth profile,a cold semi-precision forging process for manufacturing 5052 aluminum alloy multi-row sprocket was presented.Through simulating the forging process of 5052 aluminum alloy sprocket billet with 3D rigid-viscoplastic FEM,both the distributions of flow velocity field in axial(U_Z),radial(U_R) and circumferential(U_θ) directions and the curves of velocity component in different deformation regions were respectively obtained.By comparison and analysis of the velocity varying curves,the velocity component relation conditions for filling the die cavity were clarified.It shows that when the die cavity is almost fully filled,the circumferential velocity U_θ increases sharply,implying that U_θplays a key role in fully filling the die cavity.

PROPER CONDITIONS OF MESHING FOR Hy-Vo SILENT CHAIN AND SPROCKET

Proper meshing of Hy-Vo silent chain and sprocket is important for realizing the transmission of the silent chain with more efficiency and less noise. Based on the study of the meshing theory of the Hy-Vo silent chain with the sprocket and the roll cutting machining principle of the sprocket with the hob, the proper conditions of the meshing for the Hy-Vo silent chain and the sprocket are put forward with the variable pitch characteristic of the Hy-Vo silent chain taken into consideration, and the proper meshing design method on the condition that the value of the link tooth pressure angle is unequal to the value of the sprocket tooth pressure angle is studied. Experiments show that this new design method is feasible. In addition, the design of the pitch, the sprocket tooth pressure angle and the fillet radius of the sprocket addendum circle are studied. It is crucial for guiding the design of the hob which cuts the Hy-Vo silent chain sprocket.

Upper-bound and finite element analyses of multi-row sprocket during cold semi-precision forging process

The cold semi-precision forging of a multi-row sprocket was investigated using upper-bound （UB） and finite element methods combined with experiments. Based on the design of a new tooth profile for the sprocket, a cold semi-precision forging process and a kinematically admissible velocity field for filling the die cavity were proposed. Using the UB method, the velocity fields of the sprocket billet in the forming process were divided theoretically and calculated. The process of forging a multi-row sprocket was simulated using the FEM package Deform-3D V6.1 to obtain the distributions of the velocity field and the effective stress field in filling the die cavity. Similar to the simulated results, the experiment on cold forging a 5052 aluminum alloy sprocket was successfully performed. By comparing the calculated （UB method）, experimental and simulated load-stroke curves, the calculated and simulated results were basically in accordance with the experimental results. The study provides a theoretical foundation for the development of the precision forging of multi-row sprockets.

MESHING THEORY AND DESIGN METHOD OF NEW SILENT CHAIN AND SPROCKET

Based on the study of the meshing theory of a new silent chain and sprockets, and the rolling cutting theory of sprocket and hob, the harmonious relations of dominating dimensions among the new silent chain, sprocket and hob is build, the meshing conditions are expatiated, and the resolved expression, which can instruct design and calculation, is educed. The tests show that the meshing design method is feasible.

祝贺太旧高速公路东西两段竣工通车

祝贺太旧高速公路东西两段竣工通车本刊编辑部金风送爽，又值国庆佳节。今年的国庆，对山西人民来说，是喜上加喜。因为太旧高速公路东西两段，经过５万名筑路员工两年的艰苦奋战，现在如期高标准、高质量竣工通车，取得了太旧工程的第一阶段胜利。这是全省人民的一件大喜...