Self-locking nut

The utility model relates to a self-locking type nut which comprises a screw rod, the outer side of the screw rod is in threaded connection with a forward-screwing nut and a backward-screwing nut which are used for fixing the screw rod, and the outer side of the forward-screwing nut is provided with a fixing mechanism used for strengthening the self-locking capacity of the nut. A positioning mechanism used for connecting the forward-screwing nut and the reverse-screwing nut is arranged on the outer side of the reverse-screwing nut, the fixing mechanism comprises a fixing base fixed to the outer side of the forward-screwing nut, a positioning plate is movably connected to the upper surface of the fixing base, and a connecting plate is fixed to the side, away from the forward-screwing nut, of the positioning plate. According to the self-locking type nut, the fixing base and the positioning base are connected together through the fixing mechanism, so that the forward-rotating nut and the reverse-rotating nut are