Squirrel-cage rotor for asynchronous motors

A squirrel -cage rotor (1) for asynchronous motors is provided with a lamination stack (2) made of a magnetic material and a plurality of bars (8), the intermediate portions- (9) of which engage respective slots (3) of the lamination stack (2); the end portions (12) of the bars (8) protrude with respect to the lamination stack (3) at both axial ends of the rotor (1) and are fixed to two shorting rings (13); a plurality of spaces (15) are defined, axially, by the lamination stack (2) and the shorting rings (13), and tangentially by the end portions (12) of the bars (8); part of such spaces (15) is engaged by stiffening blocks (17) arranged in contact with the end portions (12) of the adjacent bars (8).