Liquid nitrogen refrigeration system for motor rotor shaft

The utility model discloses a liquid nitrogen freezing system for a motor rotor shaft, which comprises a freezing bin with a material taking and placing port, and a rotatable fixing mechanism is arranged in the freezing bin and is used for fixing the rotor shaft; an annular spray pipe is arranged above the fixing mechanism along the outer contour of the fixing mechanism, gas outlets are evenly distributed in the inner side wall of the spray pipe, the spray pipe is communicated with a liquid nitrogen inlet, and gas-liquid two-phase nitrogen is output from the gas outlets to freeze the rotor shaft. According to the utility model, gas-liquid two-phase nitrogen is uniformly sprayed by adopting the annular spray pipe, and the gas-liquid two-phase nitrogen is vaporific, can be fully and uniformly contacted with the rotor shaft and can also be subjected to cold impact on the rotor shaft, so that the rotor shaft is mildly cooled, cracks of the rotor shaft are avoided, the qualified rate of the frozen rotor shaft is i