Patent ID: 7703551

Claim:
A fluid driven down-hole drilling motor having a rotor which rotates in a first direction relative to a stator about a longitudinal axis of a well bore in which a drill string containing the motor is journalled, the rotor operative under the pressure of a drilling fluid, the drilling motor including a flex shaft mountable to the rotor, the drilling motor comprising a cylindrical flow collar mountable at a first end thereof to an opposite end of the flex shaft opposite to the rotor, said cylindrical flow collar having a cylindrical sidewall and a second end opposite said first end wherein said second end of said flow collar has a bore and is mountable to a hollow drill bit so that said bore is in fluid communication with the drill bit, wherein at least one ramped aperture is formed in said side wall of said flow collar, each ramped aperture including an inlet on an outer surface of said sidewall and a corresponding opening within said flow collar such that the drilling fluid may be directed to the bore in the second end of the flow collar, said at least one ramped aperture in fluid communication with said bore such that the drilling fluid enters said bore via, sequentially, said inlet and said opening, wherein said each ramped aperture includes an inclined ramp surface and an inclined side surface extending radially, relative to a longitudinal axis of the bore, between said inlet and said opening, said ramped surface and side ramp surface formed such that the drilling fluid flowing under pressure down past the flex shaft is directed and drawn into said ramped aperture along a fluid flow path which spirals downwardly and radially inwardly of said flow collar so as to then flow into said bore, whereby pressure loss associated with drawing the drilling fluid into said at least one ramped aperture is thereby minimized.