抄録
Drilling ability of rotary cone bits were measured experimentally at atmospheric pressure. A laboratory drilling equipment used in this study could measure accurately load to rock, torque of a bit and displacement of a bit. When a bit rotated, there occurred the vertical vibration caused by movement of each tooth of cones of the bit. This vertical vibration of a bit produced variations in torque of a bit and load to rock and also in instantaneous drilling rate. Analyses of these variations measured by this equipment would be used to understand the accurate drilling ability of rotary bits.
