Internal expansion clamp

The utility model belongs to the field of gear machining, and discloses an internal expanding clamp which comprises a fixing support and an expanding sleeve, one end of the expanding sleeve is a connecting seat, and the other end of the expanding sleeve is a petal-shaped expanding head. An expansion core is arranged in the expansion sleeve in a penetrating mode, and the free end of the expansion core is conical and can move in the axial direction of the expansion sleeve through a driving mechanism A; the connecting seat is fixed on the coupling, and the other end of the coupling is connected with the sleeve; the sleeve is connected to the fixed bracket through a bearing and is driven to rotate through a driving mechanism B; the expansion sleeve is further sequentially sleeved with a springand a stripping ring, a stroke hole is formed in the outer wall of the stripping ring in the axial direction, a limiting bolt penetrates through the stroke hole, and the bolt is fixed to the expansion sleeve. The utility mod