a squirrel - cage rotor of an asynchronous machine includes a laminated core having grooves and positioned in fixed rotative engagement on a shaft , and a squirrel cage including short - circuit rods which are received in the grooves and have opposite front faces , and short - circuit rings which connect the short - circuit rods on the front faces . shrink rings respectively surround the short - circuit rings at least radially outside and rest on the shaft . a pressure - resistant hardenable plastic is provided in a gap between the short - circuit rings and the shrink rings .