Locking device, vehicle-mounted sound equipment mounting structure and vehicle

The invention discloses a locking device, a vehicle-mounted sound equipment mounting structure and a vehicle, the locking device comprises a mounting rack, a driving unit, a swing arm, a locking piece and a connecting rod, and the driving unit is mounted on the mounting rack; one end of the swing arm is rotationally mounted on the mounting frame through a first rotating shaft; the swing arm is in transmission connection with the driving unit; one end of the locking piece is rotationally connected with the other end of the swing arm through a second rotating shaft; one end of the connecting rod is rotationally connected with the other end of the locking piece through a third rotating shaft; the other end of the connecting rod is rotationally mounted on the mounting frame through a fourth rotating shaft; wherein the first rotating shaft, the third rotating shaft and the fourth rotating shaft are distributed in a triangular shape, the axes of the three rotating shafts are parallel, and a limiting structure is ar