Stamping die structure for inner hole flanging

The utility model discloses an inner hole flanging stamping die structure which comprises a vertical driving rod, a middle sleeve arranged outside the driving rod in a sleeved mode, an outer sleeve arranged outside the middle sleeve in a sleeved mode, a sliding block arranged below the middle sleeve and a base arranged below the sliding block. The driving rod is arranged in a corresponding hole in the insert in a penetrating mode, the insert is in clearance fit with the driving rod, the shape of the top of the insert is matched with the shape of the flanging of the inner hole, the driving rod and the outer sleeve are both in sliding connection with the middle sleeve, the sliding block is in sliding fit with the base, and the base is fixedly connected with the outer sleeve. Under the combined action of the insert moving upwards and the upper die moving downwards, an oil tank opening of a wheel cover is punched to form a flanging, so that the flanging of the oil tank opening is completed while the automobile wh