Bag provided with expansion means

A bag provided with an expansion means, the bag comprising:

• a bag body having a storage space formed therein;
• a cushion pocket forming a predetermined space inside the storage space of the bag body and having an opening spatially connecting the predetermined space of the cushion pocket with the storage space of the bag body;
• and
• an expansion means which is accommodated in the cushion pocket, and of which the total volume is variable when air is injected or discharged through an injection portion, the expansion means including an expansion body forming an air injection space into which the air is injected, and the injection portion provided on the expansion body and allowing the air injection space to selectively communicate with an outside,
• wherein the injection portion comprises:
• an injection frame coupled to the expansion body of the expansion means and having an air hole through which the air passes to the air injection space, and
• a valve plate being in a flat plate shape, mounted in close contact with an edge of the air hole, and having a first end fixed to the injection frame and a movable second end opposite to the first end and positioned being in close contact with an edge of the air hole, and
• wherein the valve plate is configured to be elastically deformed by injected air when the air is injected toward the air hole such that the movable second end of the valve plate is separated from the injection frame by the injected air and opens the air hole, and the valve plate is configured to be restored to an original shape thereof when air injection is stopped such that the movable second end comes into close contact with the edge of the air hole and shields the air hole.