Single-disc central hob of shield machine

The utility model discloses a single-disc central hob of a shield machine, which comprises a cutter shaft (1), a cutter cover (6), a connecting bolt (8), a bearing inner sleeve (2), a bearing outer sleeve (3), a cutter body (4), a cutter ring (5) and a floating sealing ring (7). The bearing inner sleeve and the bearing outer sleeve matched mutually, and the cutter body and the cutter ring supported by the matched bearing inner sleeve and bearing outer sleeve are arranged in turn in the radial enlarging direction of the outer ring of the cutter shaft; the floating sealing ring is arranged between the bearing outer sleeve and the cutter cover; and the cutter shaft and the cutter cover are fixed together by the connecting bolt. The central hob is characterized in that: one cutter shaft is only fixedly connected with one cutter cover; a sealing tape is arranged on one side of the bearing outer sleeve, and the sealing tape is paired with the floating sealing ring arranged on the cutter cover to form a sealing pair; the hob has enough strength and good abrasion resistance, and the single-disc hob can be arranged in parallel on a cutter head; and when one blade is damaged, only half of the blade is replaced, so the hob is convenient to replace and install and adaptive to wide geological conditions.