Positioning device of hydraulic cylinder

The utility model belongs to the technical field of hydraulic cylinders, and particularly relates to a positioning device of a hydraulic cylinder, which comprises a concave workbench, a servo motor is fixedly mounted on one side of the concave workbench, a threaded rod is fixedly connected to the output end of the servo motor, the other end of the threaded rod is connected with the inner side wall of the concave workbench through a bearing, and the bearing is fixedly connected with the inner side wall of the concave workbench. And the surface of the threaded rod is in threaded connection with a moving plate. The arc-shaped supporting plate, the second air cylinder and the second arc-shaped clamping plate are used in cooperation to fix cylinder barrels with different cylinder diameters, and the positioning barrel, the adjusting lead screw and the first arc-shaped clamping plate are used in cooperation to fix piston rods assembled in a matched mode according to the cylinder diameters. And the positioning barrel