Mechanical gear shifting mechanism with self-locking function and engineering machinery

The utility model belongs to the technical field of mechanical gear shifting, and discloses a mechanical gear shifting mechanism with a self-locking function and engineering machinery. The mechanical gear shifting mechanism with the self-locking function comprises a speed change operating valve and a gear shifting device. The gear shifting device comprises a shell, a gear shifting rod, a turbine, a worm and a linkage assembly, the turbine and the worm are rotationally arranged on the shell, the worm is in transmission connection with the turbine, one end of the linkage assembly is in transmission connection with the worm, the other end of the linkage assembly is connected with the distribution valve rod, the gear shifting rod is fixedly arranged on the turbine, and the turbine can be driven to rotate by shifting the gear shifting rod. The worm wheel drives the linkage assembly to move through the worm so that the distribution valve rod can move, and then gear change of the gearbox is achieved. According to th