Abstract：VVT-Cam sprocket is a key part of automobile engine, which consequently require a relatively high matching precision as an automobile transmission mechanism. In this paper, based on the continuum powder material model, a simulation analysis of the density distribution of the green compact under three schematic designs was carried out using the finite element software- DEFORM. The structural and dimensional optimization of the mold and the improvement of the uniformity of density distribution were realized through the numerical simulation analysis. The results prove that the optimal design can satisfy the accuracy, density and performance requirements for the sprocket manufactured by the advanced net forming method of powder metallurgy. A upper and a bottom die structure with a powder leaking hole at the corresponding position of the keyhole is designed, so that the supersaturated powder at the keyhole can be moved and the phenomenon of overpressure can be prevented. When the size of leaking hole is small, the overpressure phenomenon can not be alleviated. When the size of leaking hole is large, the powder around the keyhole loses, forming a low density area, resulting in uneven overall density distribution. When the volume of the powder leakage hole is designed as 2/3 of the keyhole volume, the blank with the most uniform density distribution can be obtained.
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2018, Vol. 23 
