Patent ID: 7234572

Claim:
A braking band for a disk-brake disk, comprising at least two plates connected to one another by connecting elements, in which the space between the plates forms an internal air-duct for the cooling of the braking band, wherein at least one of the plates has, in one of its surfaces defining the air-ducts, at least one groove which extends substantially along at least a portion of an orbit around the axis of symmetry of the disk and has a cross-section which becomes wider, towards the air-duct, for a predominant portion of its depth such that said groove has a length and a width wherein said length is greater than five times said width, wherein the groove has a trapezoidal shape which becomes wider towards the air-duct, in which oblique sides of the trapezium are inclined at an angle of about 85° to the longer base, and the groove is produce by casting by means of trapezoidal protuberances on an annular band of a core which defines the shape of said internal air-duct.