Method for making brake discs in fiber reinforced material and brake disc made with such method

A method for making brake discs of a fibre-reinforced material, each brake disc comprising a braking band having a predetermined thickness, said method comprising the following steps:

• a) arranging a winding mandrel having a predetermined outer diameter;
• b) forming at least one layer of fibres having a predetermined width;
• c) impregnating the layer of fibres with at least one binder resin;
• d) winding the layer of fibres impregnated with resin about the mandrel to form a coaxially hollow cylindrical body of a brake disc, having a predetermined outer diameter and an inner diameter substantially equivalent to a diameter of the mandrel, the layer of fibres being wound about the mandrel according to at least one winding direction substantially parallel to a direction of a length of the layer;
• and
• e) heating the cylindrical body to at least partially cross-link the binder resin to obtain a solid semi-finished cylindrical body of a brake disc;
• f) cutting the semi-finished cylindrical body into slices transversely to a longitudinal axis of the cylindrical body according to predetermined thicknesses, each slice being a disc-shaped body which defines at least the braking band of a brake disc;
• g) post-crosslinking thermal treatment, said step g) being carried out on the semi-finished cylinder body;
• h) moulding the cylindrical body or individual slices of the cylindrical body obtained as a result of the cutting step f), the moulding step h) being carried out before the step a) of post-crosslinking thermal treatment;
• wherein the moulding step h) is carried out on the cylindrical body or on individual slices of the cylindrical body by plastically deforming in the axial direction a central portion of the cylindrical body or of the disc-shaped body defined by a single slice to obtain a coaxial cap on the cylindrical body or on the disc-shaped body, axially protruding therefrom, said coaxial cap defining a bell of the brake disc, an unreformed peripheral annular part of the cylindrical body or of the disc-shaped body defining the braking band of the brake disc.

A method for making brake discs of a fibre-reinforced material, each brake disc comprising a braking band having a predetermined thickness, said method comprising the following steps:

• a) arranging a winding mandrel having a predetermined outer diameter;
• b) forming at least one layer of fibres having a predetermined width;
• c) impregnating the layer of fibres with at least one binder resin;
• d) winding the layer of fibres impregnated with resin about the mandrel to form a coaxially hollow cylindrical body of a brake disc, having a predetermined outer diameter and an inner diameter substantially equivalent to a diameter of the mandrel, the layer of fibres being wound about the mandrel according to at least one winding direction substantially parallel to a direction of a length of the layer;
• e) heating the cylindrical body to at least partially cross-link the binder resin to obtain a solid semi-finished cylindrical body of a brake disc;
• and
• f) cutting out through openings on the layer of fibres, said cut out step f) being carried out before the step d) of winding the layer about the mandrel;
• wherein said through openings are obtained on the layer of fibres according to a row distribution, each row of openings extending in the direction of a width of the layer, the openings of one row being aligned with the openings of the other rows in the direction of the length of the layer of fibres;
• wherein interdistance between the rows of openings is adjusted as a function of the radial position that the single row must take in the cylindrical body relative to the other rows, so that during the winding step d) the openings radially overlap so as to form radial cavities, each of the radial cavities extends from the outer surface of a final cylindrical body up to a predetermined radial depth, said cavities defining radial ventilation channels formed in the thickness of the braking band of the brake disc to be obtained.