Cement bearing and retaining unit

A cement bearing and retaining unit comprises a central pipe, an upper clip sleeving the top end of the outer wall of the central pipe and a lower clip sleeving the outer wall of the central pipe. The cement bearing and retaining unit is characterized in that the outer diameter of the central pipe is provided with a reducing step, uniform distribution holes are formed at the largest outer diameter of the central pipe, shear pins are arranged in the uniform distribution holes, gaps are reserved between the upper clip and the central pipe and between the lower clip and the central pipe, an upper cone and a lower cone are respectively wedged into the gaps between the upper and lower clips and the central pipe, a rubber sleeve is axially arranged between the upper cone and the lower cone, a sleeve valve is connected to the lower end of the outer wall of the central pipe, one end of a valve body is arranged at the lower end of the inner wall of the central pipe while the other end of the same extends into the slee