Hydraulic machine for fine blanking of sheet metal

The invention discloses a hydraulic machine for fine blanking of sheet metal. The hydraulic machine comprises a machine body, a main oil cylinder, a back-pressure cylinder, a gear ring cylinder and a sliding block, wherein the gear ring cylinder is arranged in a lower workbench of the machine body; the upper end of a piston rod of the gear ring cylinder is supported in a lower guide sleeve; the lower guide sleeve is fixed in a central hole of a workbench plate; the main oil cylinder perpendicularly downward penetrates through an upper cross beam and is fixed at the center of the upper cross beam; the head part of a piston rod of the main oil cylinder is fixed on the upper side of the sliding block; the back-pressure cylinder is positioned in the sliding block; the lower side of the back-pressure cylinder is fixed inside the lower part of the sliding block; the lower end of a piston rod of the back-pressure cylinder is supported in an upper guide sleeve; and the upper guide sleeve is fixed in a central hole of