Mechanical braking structure of turning tool

The utility model relates to the field of barring tools, in particular to a mechanical braking structure of a barring tool, which comprises a barring fixing structure, a barring rotating structure, a braking gear ring and a braking module, the braking gear ring is connected with the turning fixing structure and is coaxial with a rotating shaft of the turning rotating structure, and first braking teeth are arranged on an inner ring of the braking gear ring in a circumferential array mode; the braking module comprises a braking block and a telescopic mechanism, the telescopic mechanism is arranged on the turning rotating structure, the braking block is arranged at the telescopic end of the telescopic mechanism, and second braking teeth meshed with the first braking teeth are arranged on the braking block. The barring device has the advantages that the barring fixing structure and the barring rotating structure can be completely braked at any time under the condition that large braking force is not needed due to