| 摘要 |
The invention provides a process for the injection molding of treads on a tire carcass which comprises feeding an elastomeric composition for molding the tire's tread to a plurality of equalization spaces symmetrically arranged with respect to the injection cavity of the mold where the tread is formed, the mix moving to the injection cavity from each of the spaces through a plurality of injection passages, the mix being fed to each of the spaces through at least one feeding passage and the ratio between average sliding gradients gamma i of the injection passages and gradients gamma a of the feeding passages being not lower than 8. The invention also provides an apparatus for the injection molding of a tread on a tire body having a plurality of feeding channels symmetrically arranged around the injection cavity, a plurality of equalization chambers arranged with the same symmetry and into which the feeding channels flow, and a plurality of injection orifices which connect each chamber with the cavity, the ratio between the sections of the injection orifices and the section of the feeding channels and the number of injection orifices where the delivery of each feeding channel spreads, being such that, when a fluid mix for molding the tread is flowing through them, the ratio between respective gradients gamma of average sliding is now lower than 8.
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