Device for axially retaining blades mounted on a turbomachine rotor disk
A device for axially retaining blades mounted on a turbomachine rotor disk is disclosed. The device includes a rotor disk having a plurality of slots and a flange extending radially outwards, cooperating with a bearing face of the disk to define a groove that is open radially outwards. The device also includes a plurality of blades, each having a root mounted in a slot of the disk, each blade root having a respective radial bearing face that corresponds to the bearing face of the disk and that has at least one nib extending radially inwards thereover to define a notch that is open radially inwards, and a retaining ring that is mounted against the bearing faces of the disk and of the blade roots. The retaining ring is housed in the groove of the disk, is held outwardly in the notches of the blade roots, and is constituted by a plurality of angular segments placed end to end.
1. A device for axially retaining blades mounted on a turbomachine rotor disk, the device comprising:
a rotor disk comprising:
a plurality of substantially axial slots disposed at an outer periphery of the rotor disk that are outwardly open; and
on a radial bearing face, a flange extending radially outwards to co-operate with said bearing face to define an annular groove that is open radially outwardly;
a plurality of blades, each comprising a root mounted in a corresponding slot of the rotor disk, each blade root being provided, on a radial bearing face thereof that corresponds to the bearing face of the rotor disk, with at least one nib extending radially inwards so as to cooperate with said bearing face of the blade root to define an annular notch that is open radially inwards; and
a retaining ring mounted against the bearing faces of the rotor disk and of the blade roots, said retaining ring being housed in the groove of the disk, the retaining ring being constituted by a plurality of angular segments placed end to end, each of the angular segments being a single piece assembly,
wherein an outer circumference of each of the angular segments of the retaining ring is held in the notches of the blade roots and an inner circumference of each of the angular segments of the retaining ring is held in the groove of the disk, an upstream face of each of the angular segments of the retaining ring abuts a downstream face of the blade root and a downstream face of each of the angular segments of the retaining ring abuts an upstream inner face of the nib, and
wherein the weight of at least one of the segments of the retaining ring being greater than that of the other segments,
wherein the at least one of segments with a greater weight includes an extra thickness on the downstream face of segment, the extra thickness is provided radially above a radially outer face of the flange, and
a projection extending axially in a downstream direction, the projection being provided radially above the extra thickness.
2. A device according to claim 1 , wherein each of the annular segments of the retaining ring includes outwardly open cutouts so as to enable the nibs of the blade roots to pass therethrough while mounting the retaining ring in the groove of the rotor disk.
3. A device according to claim 1 , wherein the retaining ring includes means for preventing the ring from turning in the groove of the rotor disk.
4. A device according to claim 3 , wherein at least one of the annular segments of the retaining ring includes a foldable tongue that is suitable for being folded out between two adjacent nibs of the blade roots to prevent the retaining ring from turning in the groove of the rotor disk.
5. A turbomachine, including at least one device according to claim 1 for axially retaining blades mounted on a rotor disk.
6. A device according to claim 1 , wherein the extra thickness extends circumferentially over all of the segment.
7. A device according to claim 1 , wherein the extra thickness extends circumferentially over a portion of the segment.