Impeller structure of shield pump

The invention provides an impeller structure of a shield pump. The impeller structure comprises an impeller body and a drive shaft; a runner is formed in the impeller body; a hub is provided at the center of the rear end of the impeller body; a center shaft hole used for being connected with the drive shaft is formed in the center in the hub; a medium inlet is formed in the front end of the impeller body; a medium outlet is formed in a blade of the impeller body; the medium inlet communicates with the medium outlet through the runner; a plurality of annular protrusions are provided on the periphery of the hub in the axis direction; inclined planes are provided on the upper portions of the annular protrusions; and the included angles between the inclined planes and the horizontal plane are30 degrees to 60 degrees. When the drive shaft drives the impeller to rotate, the annular protrusions can also rotate along with the impeller, so that when a high-temperature medium upwards comes to agap between the hub and a