Method and apparatus for manufacturing tyres

Abstract

A green tyre is built on a rigid toroidal support externally having a forming surface of a conformation corresponding to the inner conformation of the tyre. The built tyre is removed from the rigid toroidal support and engaged on an expandable toroidal support comprising a bladder. The green tyre engaged on the expandable toroidal support is introduced into a vulcanization mould and submitted to a vulcanization cycle.

1 - 45 . (canceled) 
     
     
         46 . An apparatus for manufacturing tyres, comprising:
 at least one rigid toroidal support externally having a forming surface of a conformation corresponding to an inner conformation of a built green tyre;   devices for building a green tyre on the rigid toroidal support;   at least one expandable toroidal support comprising at least one bladder;   devices for removing a built green tyre from the rigid toroidal support;   devices for engaging the built green tyre on the expandable toroidal support;   devices for introducing the built green tyre engaged on the expandable toroidal support into a vulcanisation mould; and   devices for curing the tyre enclosed in the vulcanisation mould.   
     
     
         47 . The apparatus as claimed in  claim 46 , wherein the rigid toroidal support is made up of a plurality of removably-engaged circumferential sectors disposed in mutual circumferential alignment relationship. 
     
     
         48 . The apparatus as claimed in  claim 46 , wherein said forming surface is substantially exempt from concavities or undercuts. 
     
     
         49 . The apparatus as claimed in  claim 46 , wherein the rigid toroidal support has bead seats axially spaced apart by a distance greater than 95% of the maximum axial distance measurable between axially opposite portions of the forming surface in parallel with a geometric axis of the toroidal support itself. 
     
     
         50 . The apparatus is claimed in  claim 46 , wherein said bladder has a main portion in the form of a layer made of elastomeric material substantially devoid of reinforcing inserts. 
     
     
         51 . The apparatus as claimed in  claim 46 , wherein the expandable toroidal support comprises:
 a pair of flanges coaxially facing each other and sealingly engaging opposite circumferential edges of the bladder; and   an inflow duct radially opening between said flanges into the bladder.   
     
     
         52 . The apparatus as claimed in  claim 46 , wherein the bladder is elastically deformable from a rest condition at which it has a substantially cylindrical conformation, to a work condition at which it is radially expanded and acts against the tyre taking the shape of an inner conformation of the tyre. 
     
     
         53 . The apparatus as claimed in  claim 51 , wherein the expandable toroidal support further comprises a centring member coaxially in engagement with said flanges. 
     
     
         54 . The apparatus as claimed in  claim 53 , wherein said centring member comprises at least one shank which is insertable in a centring seat arranged in the vulcanisation mould. 
     
     
         55 . The apparatus as claimed in  claim 51 , further comprising a pair of counter-rings in which each counter-ring is peripherally associated with one of said flanges to compress one bead of the tyre being processed against an inner surface of the vulcanisation mould. 
     
     
         56 . The apparatus as claimed in  claim 55 , wherein each of said counter-rings comprises a plurality of counter-sectors rotatably engaged in the vicinity of a peripheral edge of the respective flange and movable between a work position at which they have the respective end edges consecutively disposed along a circumferential alignment direction radially external to the flange, and a rest position at which they have the respective end edges in a radially internal position relative to the circumferential alignment direction. 
     
     
         57 . The apparatus as claimed in  claim 56 , wherein each counter-sector has an abutment tailpiece projecting from a rotation axis of the counter-sector on the opposite side from said end edge and set to act in abutment against the vulcanisation mould to inhibit rotation of the counter-sectors toward the rest position when the tyre is enclosed in the vulcanisation mould. 
     
     
         58 . The apparatus as claimed in  claim 56 , wherein the counter-sectors are movable from the work position to the maximum opened wide position to compress beads of the tyre enclosed in the vulcanisation mould against said vulcanisation mould. 
     
     
         59 . The apparatus as claimed in  claim 58 , wherein said vulcanisation mould further comprises stop seats set to act against the counter-sectors in the maximum opened wide position. 
     
     
         60 . The apparatus as claimed in  claim 46 , wherein said devices for curing the tyre comprise a feeding circuit opening into the vulcanisation mould and adapted to be operatively coupled with an inflow duct formed in the expandable toroidal support to supply a vulcanisation fluid into the expandable toroidal support. 
     
     
         61 . The apparatus as claimed in  claim 60 , wherein control devices operate on the feeding circuit to admit the vulcanisation fluid to a first pressure value for a predetermined time. 
     
     
         62 . The apparatus as claimed in  claim 61 , wherein the control devices operate on the feeding circuit to subsequently admit vulcanisation fluid to a second pressure value higher than the first pressure value. 
     
     
         63 . The apparatus as claimed in  claim 61 , wherein the first pressure value is about 1 bar to about 2.5 bars. 
     
     
         64 . The apparatus as claimed in  claim 62 , wherein the second pressure value is about 18 bars to about 30 bars. 
     
     
         65 . The apparatus as claimed in  claim 46 , further comprising devices for carrying out a lubricating treatment on the expandable toroidal support. 
     
     
         66 . The apparatus as claimed in  claim 65 , wherein said devices for carrying out a lubricating treatment operate on the expandable toroidal support positioned externally of the vulcanisation mould. 
     
     
         67 . The apparatus as claimed in  claim 46 , wherein said devices for building a green tyre on the rigid toroidal support comprise a plurality of building stations distributed along a building line, each building station being set to form one component of the green tyre directly on said rigid toroidal support. 
     
     
         68 . The apparatus as claimed in  claim 67 , wherein each of the building stations distributed along the building line operates on a respective green tyre being processed and carried by a respective rigid toroidal support being sequentially transferred from a building station to the next building station through robotized arms.