Simple expansion joint

The utility model discloses a simple expansion joint which is characterized in that two connection flanges, an outer cylinder, an inner cylinder and a plate-shaped substrate are included, the two connection flanges are in bilateral symmetry, the outer cylinder and the inner cylinder are distributed between the connection flanges from left to right, the substrate is located under the connection flanges, the outer cylinder and the inner cylinder and are fixedly connected with the connection flanges, the outer cylinder and the inner cylinder, the inner cylinder is welded to the outer cylinder, the connection flanges are provided with holes allowing connection pieces to penetrate, the diameter of the holes is consistent with that of a core hole of the outer cylinder and that of a core hole of the inner cylinder, and the diameter of the holes is equal to that of the ends of the connection pieces to penetrate. The two ends of the connection pieces to penetrate penetrate through the outer cylinder and the inner cylinder of the expansion joint respectively, and the diameter of the holes, allowing the connection pieces to penetrate, in the outer cylinder and the diameter of the holes, allowing the connection pieces to penetrate, in the inner cylinder are equal to that of the connection pieces, so that certain axial pull force and certain radial force can be well borne by additionally arranging the expansion joint on the butt joint portion of the two connection pieces, stress on bolts of a flange plate is shared, and connection reliability of the two connection pieces is guaranteed.