Air compressor structure

An air compressor structure, comprising:

• a cylinder;
• a piston, coupled in the cylinder and performing reciprocating motion to generate compressed air;
• a cylinder lid, assembled to the cylinder to receive the compressed air;
• and
• a pressure gauge, comprising:
• a propelling barrel, movably disposed in the cylinder lid and having a gear rack;
• a value panel, disposed on a surface of the cylinder lid;
• and
• a pointer, having a pointing portion and a pivot, wherein the pivot is disposed on the cylinder lid and has a gear engaged to the gear rack, and the pointing portion extends from the pivot and is located on the value panel;
• and
• a spring, disposed in the cylinder lid and abutting against the propelling barrel, wherein the compressed air provides a driving force to the propelling barrel, so that the propelling barrel moves within the cylinder lid and deforms the spring to generate an elastic force, the moving propelling barrel moves the pointing portion of the pointer on the value panel through a collaboration of the gear rack and the gear until the driving force and the elastic force are balanced, and the propelling barrel stops moving to reflect a pressure value of the compressed air,
• wherein the pressure gauge further comprises a sealing ring sleeved on the propelling barrel and abutting against an inner wall of the cylinder lid, and the sealing ring moves within the cylinder lid along with the propelling barrel.