FAN FOR A MULTI-FLOW TURBOSHAFT ENGINE, AND TURBOSHAFT ENGINE EQUIPPED WITH SUCH A FAN
The fan comprises a fan disk able to be rotationally driven about a longitudinal axis and provided at the periphery with radial blades each comprising a root slideably engaged in a groove of the disk and, on the outside thereof, a vane, platforms surrounding the disk being interposed between the radial blades. Advantageously, the fan additionally comprises shock-absorbing wedges which are arranged tangentially at the exterior periphery of said disk underneath the platforms and between two roots of adjacent radial blades, each wedge being in tangential contact with the two adjacent blades.
1 . Fan for a multi-flow turboshaft engine, comprising a fan disc which is capable of being rotated about a longitudinal axis and which is provided, on the periphery thereof, with radial blades, each comprising a root which is slidably inserted into a groove in the disc, and, on the outside of said fan, a vane, attached platforms which surround the disc by being placed between the radial blades, and damping shims which are provided in respective cavities defined by the outer surface of the disc, the roots of the vanes, and the platform,
wherein the damping shims are arranged tangentially on the outer periphery of said disc, close to the outer surface thereof, between two roots of adjacent radial blades, are elastically deformable, and have a tangential width which is at least equal to the distance separating two adjacent blades on the periphery of the disc, each shim being mounted so as to be in tangential contact, as a result of compression, with the two adjacent blades, and a fixed support being provided in each cavity receiving a shim in order to radially hold said shim in position.
2 . The fan according to claim 1 , wherein the damping shims are provided between all the blades of the disc.
3 . The fan according to claim 1 , wherein each support is fixed on one side by a first fixing member which connects the disc to a connecting flange of a compressor drum, and on the other side by a second fixing member which connects the disc to the platform.
4 . The fan according to claim 3 , wherein said support is stirrup-shaped in the form of an upside down U, between the legs of which the damping shim is arranged and which is inserted between two external radial tabs on the disc, which interact with a central radial lug on the corresponding platform and the flange, respectively, said damping shim projecting tangentially from said U-shaped support in order to be in contact with the two roots of adjacent blades.
5 . The fan according to claim 1 , wherein each damping shim has an oblong, elliptical or similar shape, having rounded opposite side edges which come into contact, as a result of compression, with the respective roots of the adjacent blades.
6 . The fan according to claim 1 , wherein a metal plate is attached to an outer face of each damping shim.
7 . The fan according to claim 6 , wherein the plate is overmoulded onto the damping shim.
8 . The fan according to claim 1 , wherein the damping shims are made of a synthetic or natural polymer material, such as an elastomer.
9 . The fan according to claim 8 , wherein the material of the shims has a hardness in a range of from 60 to 90 Shore.
10 . Twin-spool turboshaft engine comprising, from upstream to downstream in the gas flow direction, a fan, a compressor, a combustion chamber, a turbine and an exhaust nozzle, wherein the engine further comprises the fan according to claim 1 .