Patent ID: 8544567

Claim:
A drill bit having a distal end and a proximal end, the proximal end of the drill being configured to be coupled to an end of a drill string, the drill bit comprising: a cutting face at the distal end of the drill bit with one or more fixed cutting elements; a flow passage in fluid communication with the drill string and extending from the proximal end to the distal end to the cutting face; a flow interrupter contained completely within the drill bit and positioned to interrupt flow of fluid through the flow passage; a power section proximal to the flow interrupter and contained completely within the drill bit and within the flow passage, the power section having a housing and an inlet for drilling fluid flow into the housing of the power section and the power section being connected to drive the flow interrupter and cause, in operation, variable flow of fluid through the flow passage, the power section comprising a short stage positive displacement motor; and the flow passage including at least an aperture for drilling fluid flow around the power section and outside the housing, the at least an aperture and the inlet of the power section controlling, in operation, the ratio of fluid flux through the flow passage and the power section.