The invention concerns a rotary assembly for a turbomachine, comprising: a disc (16) having an external periphery having an alternation of slots (22) and teeth (20), blades (14) extending radially from the disc (16), and the roots (24) of which are engaged axially and held radially in the slots (22) of the disc, platforms (30) extending circumferentially from the blades (14) and which are arranged circumferentially end to end, opposite each other, axial sealing means upstream and/or downstream of an annular zone extending radially from the platforms (30) as far as the disc (16). According to the invention, the sealing means comprise radially an internal annular part (64) and an external annular part (66) structurally separate from each other, and the facing radial ends of which are adapted for a relative radial movements by sliding sealingly, only an absorption of the centrifugal forces of the external part (66) being provided rotationally by the platforms (30).