Combined self-centering clamping mechanism

The utility model discloses a combined automatic centering and clamping device comprising a clamp body and a hydrocylinder internally provided with a piston, wherein one end of the clamp body is provided with a plunger piston, and the other end is sealed; the piston supports and is connected with the plunger piston; the clamp body behind the plunger piston is internally provided with a sealing cavity leading to the outer surface of the circumference of the clamp body; an elastic sleeve is arranged at the circumference of the clamp body corresponding to the sealing cavity; the sealing cavity is internally provided with pressure transmission medium; and the outer circumference of the elastic sleeve is also sleeved with an elastic expanding sleeve. The combined automatic centering and clamping device has high centering precision, rapid clamping speed and small shape error.