Self-adaptive bearing clearance spacer ring for central hob

The utility model discloses a center hob self-adaptive bearing clearance spacer ring which comprises a self-adaptive bearing clearance adjusting spacer ring, a hob lower support is arranged at the top of the self-adaptive bearing clearance adjusting spacer ring, a hob upper support is arranged at the top of the hob lower support, two bearing inner rings are arranged in the hob lower support, and a bearing inner ring is arranged in the bearing inner rings. Bearing outer rings are rotationally connected to the interiors of the bearing inner rings, a hob hub is connected to the top of the hob upper support through a floating seal, and two hob rings are symmetrically arranged at the top of the hob hub; according to the utility model, the design is simple and practical, and the tunnel boring machine can be normally propelled in a hard rock stratum with the rock stratum strength of more than 150MPa, so that the hobbing cutter and the bearing have an automatic adjustment effect, the problem of abnormal scrapping of