| 摘要 |
PROBLEM TO BE SOLVED: To provide a digging head having excellent digging efficiency and less damaging a digging claw, a drilling device, a press-in machine, and a drilling method. SOLUTION: This digging head 30 comprises an outer peripheral head 31 and a center head 32 installed at the center of the outer periphery head 31. The outer periphery head 31 and the center head 32 are rotatable and vertically movable independently of each other. By rotating the center head 32 at a higher speed than that of the outer periphery head 31, and controlling the peripheral speed of the digging claw 33 of the center head 32 to approximately the same as that of the digging claw 33 of the outer periphery head 31, the digging efficiency can be increased. When the center head 32 and the periphery head 31 are rotated in directions reverse to each other, the directional deviation of a drilled hole 3 can also be reduced. In addition, by digging the outer peripheral part of a guide hole 4 after the guide hole is drilled by the center head 32, run-out is reduced, accuracy in the drilling direction is increased, and damage to the digging claw 33 can be reduced. COPYRIGHT: (C)2006,JPO&NCIPI
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