Process for making a tyre crown protection or reinforcing layer, the layer obtained and tyres including such a layer.

摘要

1. A process for producing a reinforcement ply (41) for use in the crown of a tyre (40), this process comprising the following features : (a) a strip (48) of three-dimensional fabric (43) is used, this strip having two side faces (4), two main faces (5), and at least two discontinuous portions (49) ; (b) each discontinuous portion is formed of at least two layers of fabric (7a, 7b), the faces facing these layers, known as "discontinuity faces" (70a, 70b), extending from one side face to the other ; (c) the strip is cut at these two discontinuous portions (49) in such a manner as to obtain a ply (51A) having two ends (52-1, 52-2) ; (d) in each discontinuous portion (49) the cut is effected through the entire thickness and over the entire width of each layer of fabric so as to obtain one of the ends of the ply, this end having an "abutment surface" (53) formed both by the cut surface (5a, 5b) of each layer and by a "discontinuity surface" this discontinuity surface being formed by part or all of at least one discontinuity face, said abutment surface thus joining the two main faces and the two side faces of the ply ; (e) the two ends of the ply are joined end to end by placing the abutment surface of one end into contact with the abutment surface of the other end over their entire areas, the abutment surface of one end then having substantially the same shape and the same area as the abutment surface of the other end ; this process being characterised by the following features : (f) the fabric (43) has a three-dimensional body (44) and reinforcement cords (45, 46) arranged within said body and held in place by said body, substantially all the voids in the fabric being capable of being impregnated with at least one material which forms part of the constitution of the tyre ; (g) at these two discontinuous portions (49), the cut is effected between the reinforcement cords (45, 46) ; (h) in each discontinuous portion the cut is effected along crossed planes (Pa , Pb ), each plane passing through a layer, the strip being arranged in such a manner as to have a generally flat shape ; (i) the body comprises weft threads (33) and warp threads (32), the weft threads being arranged between the warp threads substantially in several parallel planes, called weft planes (P33 ), within the thickness of the strip ; (j) the reinforcement cords (45, 46) are substantially arranged in at least two planes (P45 , P46 ) within the thickness of the strip, each layer of the discontinuous portions having at least one plane of reinforcement cords, the reinforcement cords having the same orientation in each plane, each plane of the reinforcement cords being parallel to the planes of the weft threads, or joined with one of these planes.