| 摘要 |
PROBLEM TO BE SOLVED: To provide the rotary excavating machine of a shield propulsion machine for excavating bedrock for reducing the generation of wearing based on the difference in distance from a rotation center while maintaining the durability of the bearing of an annular excavation blade. SOLUTION: Conical roller bits 9 (a, b) in a pair so that they obliquely oppose the front central part of a cutter head 2 each other are arranged at a position where the apex of a virtual cone that is circumscribed to is separated from a rotary shaft RC of the cutter head 2 by the amount of eccentricity so that they simultaneously come into contact with a surface where first to third annular blades that are integrated and have different radii orthogonally cross the rotary shaft RC, namely the rock surface of the natural ground, thus allowing the conical roller bits 9 to roll along the rock surface without sliding greatly even if the bits 9 are provided near the rotary shaft RC since the radius of a first annular blade 93 near the rotary shaft RC is small, operating an appropriate amount of prying force to the rock surface of the natural ground and hence preventing the compaction phenomenon of grit from occurring easily, and greatly reducing the wearing of the tool nose of the roller bits that are generated by the extreme difference in slide friction caused by the difference in arrangement positions. |
