| 摘要 |
A sectorial force balanced drill bit, including conventional and bi-center drill bits, having the true center of rotation the same as, or about the same as, the bit mass axis. The bit mass axis is a longitudinal axis located off-center to the geometric axis of the bit and comprises the center of mass point. This balancing allows a greater longevity for the cutters. Additionally, a method for sectorially force balancing drill bits is provided. The method includes dividing the drill bit into one or more sections, calculating the magnitude and direction of the resultant radial imbalance force for the cutters of each section, adjusting the cutters and/or blades until the magnitude of the resultant radial imbalance force is about the same for each section and the direction of the resultant radial imbalance force for each section is about 2pi/n, where n is the number of sections, from the adjacent section.
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