Perfectionnements à l'armature de sommet des pneumatiques

摘要

836,290. Pneumatic tyres. COMPAGNIE GENERALE DES ETABLISSEMENTS MICHELIN. Feb. 17, 1958 [Feb. 16, 1957; June 3, 1957], No. 5156/58. Class 144 (2). A pneumatic tyre has a crown reinforcement of rubber embedded cord plies, the cords of which are crossed in at least the central band of the reinforcement and the side bands of the reinforcement flanking said central band having a greater resistance to flexure under the influence of forces tending to produce side slip of the tyre tread. The greater rigidity of the side bands may be effected by a smaller cord angle or by the use of cords or embedding rubber of different physical characteristics from those in the central band. The plies of the respective bands may be independent, either abutting or overlapping, Fig. 7, at the adjacent side edges of the bands, or at least one of the central band plies may extend continuously across the full width of the reinforcement, Fig. 6. The central band may be three times as wide as each side band, and where the adjacent band plies overlap such overlap may be for one-quarter to onesixth the width of the central band. The crown reinforcement may comprise a ply of radial cords extending either the full width of the reinforcement or across each side band only, in which latter case such plies may comprise extensions of carcase plies. The carcase may be devoid of cord reinforcement or may comprise bead to bead radial cord plies. Fig. 1 shows side bands 1 and 3 of cross-laid plies of cords 4, 5 and 41, 51 subtending a cord angle with the circumferential direction of from 0 to 30 degrees, and a central band 2 of cross-laid plies of cords 6, 7 having a cord angle of from 15 to 50 degrees, the reinforcement including a full width ply of radial cords 9. The cords in each ply may be discontinuous short lengths or may be continuous across the reinforcement as shown in heavy lines in Fig. 2. The reinforcement may comprise embedding rubber of higher modulus of elasticity than the tread rubber. Specifications 628,060, 677,166, 698,915 and 789,770 are referred to.