Self-lock device of motor connecting box cover

The utility model relates to a motor self-lock device, in particular to a self-lock device of a motor connecting box cover. The self-lock device of the motor connecting box cover solves the problems that when connection and disconnection of an existing motor connecting box cover are carried out, a bolt is prone to dropping, operation is difficult, and a machine is easy to damage. The self-lock device of the motor connecting box cover comprises a connecting box cover body, wherein a bolt is screwed on the connecting box cover body, a gasket is sleeved on the bolt, a column-shaped hole is formed in the lower portion of a bolt hole of the connecting box cover body, the diameter of the column-shaped hole is larger than the diameter of the bolt hole, a rubber ring located inside the column-shaped hole is tightly sleeved on the bolt, and the distance between the rubber ring and the gasket is smaller than the thickness of the connecting box cover body. The self-lock device of the motor connecting box cover is reason