Telescopic flanging inner expansion assembly and flanging device

A telescopic flanging inner expansion assembly for a pulp molded cup lid, comprising:

• a fixed air supply seat (1);
• a rotating shaft (2), wherein the rotating shaft (2) is configured to be in an upright state, the rotating shaft (2) penetrates through the fixed air supply seat (1) and is rotatable relative to the fixed air supply seat (1);
• a flanging positioning seat (3), wherein the flanging positioning seat (3) is mounted at a top of the rotating shaft (2);
• movable inner expansion blocks (4), wherein the movable inner expansion blocks (4) are circumferentially and evenly distributed around an axis line of the flanging positioning seat (3), and the movable inner expansion blocks (4) are configured to translate in a plane perpendicular to the axis line of the flanging positioning seat (3);
• a pneumatic driving mechanism, wherein the pneumatic driving mechanism comprises at least one first air passage (Q1) formed in the fixed air supply seat (1), and at least one second air passage (Q2) formed in the flanging positioning seat (3), each of the at least one first air passage (Q1) is communication with one of the at least one second air passage (Q2), and configured to supply air to drive the movable inner expansion blocks (4) to translate in the plane perpendicular to the axis line of the flanging positioning seat (3).