A rotor (101, 201) for an induction machine, the rotor (101, 201) comprising - a ferromagnetic rotor core structure, - a plurality of rotor bars (103, 104) in slots of the rotor core structure, and - a first end ring and a second end ring electrically connecting first ends and second ends of the rotor bars (103, 104), respectively, to each other at a first end and a second end of a cage winding, respectively, wherein the cage winding is constituted by the rotor bars (103, 104) and the first and second end-rings (105, 106), wherein the first and second ends of the rotor bars (103, 104) are attached to openings of the first and second end-rings (105, 106), respectively, by expansion of the first and second ends of the rotor bars (103, 104) in transverse directions of the rotor bars (103, 104), the expansion being caused by axial press having been directed to the first and second ends of the rotor bars (103, 104) and wherein material of the rotor bars (103, 104) is softer than material of the first and second end-rings (105, 106), characterized in that the rotor (101, 201) further comprises one or more ring-shaped disc springs (107, 108) surrounding a geometric axis of rotation of the rotor (101, 201), the one or more ring-shaped disc springs (107, 108) being axially between the first and second end-rings (105, 106), respectively, and the rotor core structure, and radially between the rotor bars (103, 104) and the geometric axis of rotation of the rotor (101, 201), and the one or more ring-shaped disc springs (107, 108) being axially compressed and, as a corollary of axial compression, being radially spread against the rotor bars (103, 104) so that the one or more ring-shaped disc springs (107, 108) are arranged to press the rotor bars (103, 104) radially away from the geometric axis of rotation of the rotor (101, 201) and to maintain the balance of the rotor (101, 201) during rotation of the rotor (101, 201). - a ferromagnetic rotor core structure, - a plurality of rotor bars (103, 104) in slots of the rotor core structure, and - a first end ring and a second end ring electrically connecting first ends and second ends of the rotor bars (103, 104), respectively, to each other at a first end and a second end of a cage winding, respectively, wherein the cage winding is constituted by the rotor bars (103, 104) and the first and second end-rings (105, 106), wherein the first and second ends of the rotor bars (103, 104) are attached to openings of the first and second end-rings (105, 106), respectively, by expansion of the first and second ends of the rotor bars (103, 104) in transverse directions of the rotor bars (103, 104), the expansion being caused by axial press having been directed to the first and second ends of the rotor bars (103, 104) and wherein material of the rotor bars (103, 104) is softer than material of the first and second end-rings (105, 106), characterized in that the rotor (101, 201) further comprises one or more ring-shaped disc springs (107, 108) surrounding a geometric axis of rotation of the rotor (101, 201), the one or more ring-shaped disc springs (107, 108) being axially between the first and second end-rings (105, 106), respectively, and the rotor core structure, and radially between the rotor bars (103, 104) and the geometric axis of rotation of the rotor (101, 201), and the one or more ring-shaped disc springs (107, 108) being axially compressed and, as a corollary of axial compression, being radially spread against the rotor bars (103, 104) so that the one or more ring-shaped disc springs (107, 108) are arranged to press the rotor bars (103, 104) radially away from the geometric axis of rotation of the rotor (101, 201) and to maintain the balance of the rotor (101, 201) during rotation of the rotor (101, 201). wherein the first and second ends of the rotor bars (103, 104) are attached to openings of the first and second end-rings (105, 106), respectively, by expansion of the first and second ends of the rotor bars (103, 104) in transverse directions of the rotor bars (103, 104), the expansion being caused by axial press having been directed to the first and second ends of the rotor bars (103, 104) and wherein material of the rotor bars (103, 104) is softer than material of the first and second end-rings (105, 106), characterized in that the rotor (101, 201) further comprises one or more ring-shaped disc springs (107, 108) surrounding a geometric axis of rotation of the rotor (101, 201), the one or more ring-shaped disc springs (107, 108) being axially between the first and second end-rings (105, 106), respectively, and the rotor core structure, and radially between the rotor bars (103, 104) and the geometric axis of rotation of the rotor (101, 201), and the one or more ring-shaped disc springs (107, 108) being axially compressed and, as a corollary of axial compression, being radially spread against the rotor bars (103, 104) so that the one or more ring-shaped disc springs (107, 108) are arranged to press the rotor bars (103, 104) radially away from the geometric axis of rotation of the rotor (101, 201) and to maintain the balance of the rotor (101, 201) during rotation of the rotor (101, 201).