Single-rod type presser foot driving structure of sewing machine

The utility model relates to a single-rod type presser foot driving structure of a sewing machine, which comprises a mounting seat, a transmission crankshaft connected with the mounting seat, a first connecting rod, a cam crank connected with a main shaft of the sewing machine, a second connecting rod connected with a presser foot, and an extension crank, the two ends of the first connecting rod are rotationally arranged on the transmission crankshaft and the cam crank respectively, one end of the second connecting rod is rotationally arranged on the transmission crankshaft, the other end of the second connecting rod is used for being connected with a presser foot, one end of the extension crank is rotationally arranged on the cam crank, and the other end of the extension crank is used for being connected with the presser foot. And the other end of the extension crank extends to the outer side of the machine body of the sewing machine and is connected with an output shaft of a motor. The extension crank and t