Run flat device

A run flat device intended to be mounted in a tyre around a wheel rim of a vehicle, the device comprising at least one assembly of two monobloc half-shells assembled axially, each monobloc half-shell being made of a composite material based on fibres embedded in a thermoplastic or thermosetting resin, each monobloc half-shell comprising a radially internal periphery, a radially external periphery and a lateral wall connecting the radially internal periphery to the radially external periphery configured so as to form an internal recess within said at least one assembly that is axially closed by the lateral wall of each monobloc half-shell and each monobloc half-shell further comprising a plurality of circumferentially distributed anti-compression ribs extending, within the internal recess, radially from the radially external periphery towards the radially internal periphery,

• wherein each monobloc half-shell comprises a frustoconical surface extending circumferentially from the radially internal periphery towards the radially external periphery over at least one portion of the lateral wall, said frustoconical surface being designed to ensure a positioning of a wedge between said monobloc half-shell and a bead of a tyre so that said bead of the tyre is locked against the rim of the wheel,
• wherein each monobloc half-shell comprises at the level of its radially internal periphery a plurality of anti-bending buttresses interposed between the anti-compression ribs, each anti-bending buttress being circumferentially distributed and extending radially from the radially internal periphery towards the radially external periphery, each anti-bending buttress being housed in a portion of the internal recess formed by the frustoconical surface.