Balancing system for turbomachine rotor

A turbomachine rotor balancing system comprising a balancing flange provided with an annular core delimited radially in a first direction by a junction zone from which a plurality of through-passageways extends radially in said first direction toward a radial free flange end, each through-passageway having a radial summit, in a second direction opposite to said first direction, belonging to said junction zone;

• and
• a plurality of balance weights fixedly mounted onto said balancing flange by at least one screw/nut assembly passing through one of said passageways, a head of the screw pressing against a first face of said balancing flange and said balance weight pressing against a second face of said balancing flange, opposite to the first face,
• wherein, for each of said through-passageways, said balancing flange has on its first face a first recess passing via said radial summit and extending on either side of said junction zone, this first recess being deprived of contact with the screw head, said balancing flange having, on its second face, a second recess passing via said radial summit and extending on either side of said junction zone, this second recess being deprived of contact with said balance weight.