Turbine engine impeller
View Patent ↗A turbine engine rotor wheel including a disk including at least one slot formed in its outer periphery for mounting roots of blades, a presser being mounted between each blade root and a bottom of the slot. The presser is bistable in position and is capable of occupying a first stable position for assembly and disassembly in which it does not exert a force on the blade root, and a second stable position in which it exerts a radial force on the blade root to hold the blade stationary and to stabilize the blade in a final position.
1. A turbine engine rotor wheel comprising:
a disk including a slot formed in an outer periphery for mounting a root of a blade; and
a presser mounted between the blade root and a bottom of the slot, the presser being bistable in position, being capable of occupying a first stable position for assembly and disassembly in which the presser does not exert a force on the blade root, and a second stable position in which the presser exerts a radial force on the blade root to hold the blade stationary and to stabilize the blade in a final position,
wherein a shape and a weight of the presser are determined so that passage from the first stable position to the second stable position is performed by centrifuging,
wherein the presser comprises a spring blade that is deformable between the first and second positions,
wherein ends of the spring blade bear against the bottom of the slot and the spring blade includes a deformable central zone that is bistable in position, and
wherein the central zone of the spring blade includes a flyweight.
2. A wheel according to claim 1 , wherein the ends of the spring blade include curved rims that are folded towards the central zone.
3. A wheel according to claim 1 , wherein the presser is made of a material having shape memory, which is deformable under mechanical, thermal, or electric stress.
4. A wheel according to claim 1 , wherein the disk includes a circumferential slot in which the blade roots and the pressers are engaged.
5. A wheel according to claim 4 , wherein at least one circumferential end of each presser includes at least one tongue for bearing against the corresponding blade root.
6. A method of assembling and balancing a wheel comprising a disk including a slot formed in an outer periphery for mounting a root of a blade; and a presser mounted between the blade root and a bottom of the slot, the presser being bistable in position, being capable of occupying a first stable position for assembly and disassembly in which the presser does not exert a force on the blade root, and a second stable position in which the presser exerts a radial force on the blade root to hold the blade stationary and to stabilize the blade in a final position, wherein a shape and a weight of the presser are determined so that passage from the first stable position to the second stable position is performed by centrifuging, the method comprising:
mounting the blade and the presser in a mounting position in the slot of the disk;
causing the wheel to rotate at a speed that is fast enough to move the blade by centrifuging into a normal operating position and to cause the presser to pass into the second stable position so as to stabilize the blade in an operating position; and
balancing the wheel to eliminate any unbalance,
wherein a spacer is mounted circumferentially between two blades prior to one of the blades being held by the presser, the spacer being removed after the one of the blades is held by the presser.
7. A method according to claim 6 , wherein the presser is caused to pass into the second stable position by rotating at a speed faster than 2000 rpm, or during an operation of positioning an end of the blade.