Filling structure self-adaptive to packaging bags of different specifications

The invention provides a filling structure self-adaptive to different specifications of packaging bags, which is characterized by comprising a mounting rack, a barrel, a lower barrel, bag opening mechanisms, bag holding mechanisms, bag pressing mechanisms and vibrators, the barrel and the lower barrel are both arranged on the mounting rack, the barrel is located above the lower barrel, the bag opening mechanisms are arranged on two sides of the lower barrel, and the bag holding mechanisms are arranged on two sides of the lower barrel. The bag holding mechanisms are arranged at the two ends of the mounting frame, the bag pressing mechanism is arranged on the bag opening mechanism and used for pressing the opening portion of the packaging bag opened by the bag opening mechanism, and the vibrators are arranged on the two sides of the barrel. According to the bag opening mechanism and the bag holding mechanism, the stretching range of a bag opening air cylinder and a pushing air cylinder is adjusted through a str