Method for assembling at least one ring cooperating by shrinking with a shrink-fitting surface of a part

A method for assembling at least one ring cooperating by shrinking with a shrink-fitting surface of a part defining a reference axis and having a through axial cavity, the shrink-fitting surface being turned radially away from the reference axis, the part having a free upper end and an inner wall extending around the reference axis turned radially toward the reference axis and extending axially while delimiting at least part of the axial cavity, the assembly method comprising:

• a step of forming, on the inner wall, splines extending axially;
• a step for shrinking the ring on the shrink-fitting surface of the part so that a lower transverse face of the ring comes into abutment against a shoulder of the part;
• the assembly method comprising, after the step of forming the splines and prior to the step of shrinking the ring onto the shrink-fitting surface of the part, a step of radial elastoplastic expansion of an upper portion of the part, which results in a widening of the shrink-fitting surface and of a portion of the splines, the subsequent shrinking of the ring on the shrink-fitting surface causing a deformation of the upper portion such that said portion of the splines approaches the reference axis.