| 摘要 |
<p>A pneumatic tyre comprises a tread portion (2) provided with tread grooves (G) defining a groove bottom (9S), and a mould parting line (ML) in the groove bottom, the mould parting line (ML) extending circumferentially of the tyre, wherein the groove bottom (G) is provided with a protrusion (10) protruding radially outwardly from the groove bottom (9S) and extending along the mould parting line (ML), and the width of the protrusion gradually decreases from the groove bottom (9S) to the radially outer end (10E) of the protrusion (10). A mould comprises a tread shaping face (22) for shaping the tread portion, and at least two moulds (21U,21L) having split faces forming a parting line (ML) on the tread shaping face (22), the tread shaping face (22) being provided with protruding parts for forming the tread grooves, wherein the parting line (ML) extends across at least one of the protruding parts so that the mould parting line (ML) runs substantially circumferentially in the groove bottom of a moulded tyre, and in the above-mentioned at least one of the protruding parts, a corner (K) between the tread shaping face (22) and each of the split faces being cut off so that a gradually decreasing gap is formed between the split faces. <IMAGE></p> |
