Double-layer self-centering clamp

A double-layer self-centering clamp comprises three clamping blocks which are evenly arranged in the circumferential direction, the three clamping blocks are fixedly connected with three sliding blocks on a hydraulic chuck through bolts respectively, bolt holes used for installing bolts are formed in the clamping blocks, and a rigid clamping part matched with a differential shell is arranged on the right side of each clamping block. An elastic clamping part matched with the differential mechanism shell is arranged on the left side of the clamping block, and a through groove is formed in one side of the elastic clamping part. The three clamping blocks can be opened and closed along with the three sliding blocks on the hydraulic chuck, a through groove is formed in one side of the elastic clamping part, and the elastic clamping part can have trace elastic deformation, so that circumferential positioning of the differential mechanism shell can be more tightly attached. 一种双层自定心夹具，所述双层自定心夹具包括圆周均匀布置的三个夹块，三个夹块分别与液压卡