To provide a rock bit capable of reducing a surface pressure from a pit wall and suppressing the occurrence of vibrations.
According to a first embodiment, the rock bit includes a bit body having a journal, a cone capable of rotating relative to the bit body, a bearing between the cone and the journal, and a seal disposed between the cone and the journal to seal up the bearing; the cone has a gauge surface which comes into contact with the sidewall of a pit; and the gauge surface is covered with a diamond composite material, which is preferably spread widely and smoothly over the gauge surface. In a second embodiment, the bit body is provided with a ring bit disposed on its outer periphery. The cone of the tri-cone bit does not have a gauge chip nor a surface chip contacting the sidewall of the pit, but has only a cemented carbide chip contacting the bottom of the pit.
| JP2001295576A | 2001-10-26 |
Hideto Asamura
Hajime Asamura
Tadashi Tanaka
Toru Mori
Yutaka Yoshida
Ken Kanai
Katsunori Shirae
Hiroyuki Hashimoto
Next Patent: CONTROL SYSTEM FOR VARIABLE DAMPING DAMPER IN VIBRATION CONTROL STRUCTURE