Internal expansion clamp

The utility model belongs to the field of gear machining, and particularly discloses an internal expansion clamp which is fixed on a support and comprises an expansion sleeve, a connecting seat is arranged at one end of the expansion sleeve, and a petal-shaped expansion head is arranged at the other end of the expansion sleeve. An expansion core is arranged in the expansion sleeve in a penetratingmode, 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. The base is fixed on the coupling, and the other end of the coupling is sleeved with the fixed sleeve; the sleeve is fixed to the support, the expansion sleeve is further sequentially sleeved with a spring and a stripper ring, a stroke hole is formed inthe outer wall of the stripper ring in the axial direction, a limiting bolt is arranged in the stroke hole in a penetrating mode, and the bolt is fixed to the expansion sleeve. The utility model aimsto solve the problems of di