Method and Apparatus for Manufacturing Pneumatic Tyres

A method of manufacturing a pneumatic tyre for a vehicle wheel, comprising the steps of:

• setting a green tyre comprising a tread band having a radially external surface, on a toroidal support provided with an outer surface conforming in shape to an inner surface of the tyre;
• setting a vulcanisation mould having a moulding cavity defined by two half shells adapted to be moved close to each other in an axial direction and circumscribed by centripetally approachable circumferential sectors carrying forming ridges facing a geometric axis of the moulding cavity and movable in through slits set in the half shells;
• closing the tyre into the moulding cavity;
• pressing the tyre against the outer surface of the toroidal support;
• administering heat to the inner surface of the tyre pressed against the toroidal support keeping the circumferential sectors spaced apart from the radially external surface of the tread band;
• centripetally approaching the circumferential sectors of the mould to cause at least partial penetration of the forming ridges into the radially external surface of the tread band of the tyre;
• pressing the radially external surface of the tread band of the tyre against a radially internal surface of the moulding cavity;
• and
• administering heat to the tyre penetrated by the forming ridges of the circumferential sectors.

An apparatus for manufacturing pneumatic tyres for vehicle wheels, comprising:

• a toroidal support having an outer surface conforming in shape to the inner surface of a green tyre under working conditions comprising a tread band provided with a radially external surface;
• devices for arranging the green tyre on the toroidal support;
• a vulcanisation mould having two half shells adapted to be moved close to each other to define a moulding cavity and centripetally-approachable circumferential sectors circumscribing the moulding cavity and carrying forming ridges facing the geometric axis of the moulding cavity and movable in through slits set in said half shells;
• devices for closing the tyre into the moulding cavity;
• devices for pressing the tyre enclosed in the moulding cavity against the outer surface of the toroidal support;
• first devices for administering heat to the inner surface of the tyre pressed against the toroidal support;
• driving devices to be activated subsequent to closure of the tyre into the moulding cavity to cause translation of the circumferential sectors between a first work condition at which the forming ridges are radially spaced apart from the radially external surface of the tread band of the tyre enclosed in the moulding cavity, and a second work condition at which the forming ridges penetrate at least partly into the radially external surface of the tread band;
• devices for pressing the radially external surface of the tread band of the tyre against a radially internal surface of the moulding cavity;
• and
• second devices for administering heat to the tyre penetrated by the forming ridges of the circumferential sectors.