Method and apparatus for moulding and curing tyres for vehicle wheels
AssigneePirelli Pneumatici S.p.A.
InventorRenato Caretta
Life of this patent
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Abstract
A method of molding and curing tires for vehicle wheels includes the steps of disposing a tire being processed on a toroidal support, enclosing the tire and the toroidal support inside a molding cavity defined in a vulcanization mold, pressing the outer surface of the tire against the molding cavity walls, and administering heat to the tire to cause molecular crosslinking of the tire. The pressing step includes the steps of compressing side portions of the tire between the molding cavity walls and the outer surface of the toroidal support, concurrently with the closing step, and imposing an expansion to a radially-outer portion of the tire to bring the radially-outer portion of the tire against the walls of the molding cavity.
Claims33
A method of moulding and curing tires for vehicle wheels, comprising the following steps:
- disposing a tire being processed (7) on a toroidal support (10) the outer surface (10a) of which substantially mates an inner surface (7b) of the tire itself;
- closing the tire (7) and the toroidal support (10) inside a moulding cavity (6) defined in a vulcanization mould, said moulding cavity (6) having walls the shape of which matches that of an outer surface (7a) of the tire (7) when vulcanization has been completed;
- pressing the tire (7) by its outer surface (7a) against the moulding cavity (6) walls;
- administering heat to the tire being processed (7) to cause a molecular crosslinking of same, characterized in that said pressing step comprises the following actions:
- compressing side portions (8) of the tire (7), extending away from the inner circumferential edges (8a) thereof, between the walls of the moulding cavity (6) and the outer surface (10a) of the toroidal support (10) concurrently with said closing step;
- imposing an expansion to a radially outer portion (9) of the tire (7), delimited between said side portions (8), to bring said radially outer portion (9) against the inner walls of the moulding cavity (6).
An apparatus for moulding and curing tires for vehicle wheels, comprising:
- a toroidal support (10) arranged to engage a tire being processed (7), said toroidal support (10) having an outer surface (10a) substantially mating an inner surface (7b) of the tire itself;
- a vulcanization mould (2) arranged to receive the toroidal support (10) carrying the tire being processed (7) within a moulding cavity (6) having a tire-holding space delimited between the outer surface of the toroidal support (10) and walls of the moulding cavity (6) itself mating an outer surface (7a) of the cured tire (7);
- pressing devices (4a, 4b, 13, 19) for pressing the outer surface (7a) of the tire (7) against the inner wall of the mould (6);
- heating devices for transmitting heat to the tire (7) enclosed in the moulding cavity (6),
- characterized in that, under said closed condition, said holding space has radially inner portions having shape and sizes substantially corresponding to the shape and sizes of side portions (8) of he tire (7), extending away from inner circumferential edges (5b) of same, and a radially outer portion having radial dimensions greater than the radial dimensions of a radially outer portion (9) of the tire (7) extending between the side portions (8) of the tire itself.
Dependencies are inferred from the claim text.