Integrally bladed disk comprising a hub having a face which is recessed relates a filling member

A blisk (11) for a turbomachine fan, this disc (11) comprising a hub (12) delimited by an upstream face (16) and a downstream face (17) and an outer peripheral face (14 ) and an inner peripheral face (15) of revolution defining an inner opening, the hub (12) carrying the blades (13) each having a leading edge (18) and a trailing edge (19), the hub (12 ) and the blades (13) constituting an integral assembly. The upstream face (16) and / or the downstream face (17) is offset by being located along the axis of rotation (AX) between the leading edges (18) and trailing edges (19) of the blades (13), the blisk (11) comprising a filling member (21) attached to the remote side, the filling member (21) comprising an inner centering collar (22) engaging in the inner face (15) the hub, a radial portion (23) pinning against the remote surface and an outer shroud (24) extending from the outer peripheral face (14) of the hub.