Radial car tyre mfr. to reduce waviness in breaker layer and breaker building drum

摘要

In a process for mfg. a vehicle tyre with a radical carcass: a) the radially inner breaker layers (11,13) are preformed with a wave-like cross-section in which at least one axial area (30',31') corresponding to a tread channel has a large radial, than other axial areas; b) a radially outer breaker layer (14) with circumferentially parallel cords is wrapped over the inner breaker layers (11,13) and the tread strip is wound around the breaker assembly (11,13,14); c) the breaker and tread assembly (11,13,14) is then combined with a performed carcass and moulded and vulcanised. A drum for building the breaker layers (11,13,14) has a contoured surface with circumferential raised areas of larger dia. (30,31,32;30',32',32') spaced across the axial direction and corresponding to the circumferential channels of the tread profile.