Abstract: A downhole drilling motor located near the end of a rotary drill string is powered by the drilling fluid for driving a rotary drill bit for the drilling of an oil or gas well or the like. Substantially all of the drilling fluid that exits the power producing section is channeled toward the nozzles of the drill bit with a small portion being diverted through the bearings of the motor. A series of elastomer flow restrictor elements, each responding to increased fluid pressure by reducing the flow area therethrough, controls the fluid flow through the bearings to within a narrow range of flow rates.

Abstract: A series of axially stacked rolling bearing assemblies for transmitting axial thrust load between relative rotating cylinders, such as in a fluid powered downhole motor, is provided with the bearing races of each assembly formed from a bearing material significantly softer than the balls thereof so as to readily wear to a condition wherein the thrust load is generally equally distributed throughout each assembly within the stack.

Abstract: An improved quick release coupling assembly for a drive shaft of a downhole motor is disclosed. The quick release coupling has an internally tapered collar to cause the mating taper on the outside surfaces of the clutch dogs to be held firmly by the collar and in intimate engaging relationship between the mating tapered surfaces. The angle of the mating tapered surfaces is greater than a self-locking angle so that the quick release feature permits easy disassembly of the joint, and thus the tool, on the rig floor or as well as in the shop.

Abstract: A downhole drilling motor located near the end of a rotary drill string is operated by the drilling mud for driving a rotary drill bit to drill an oil or gas well or the like. Fluid lubricated bearings are employed and a portion of the drilling fluid is diverted through the bearings of the downhole motor with the balance of the drilling fluid being discharged through ports of the drill bit. The diverted portion of the drilling fluid is transmitted along a flow path that results in an abrupt change of direction of flow. The flow path will purge a portion of the drilling fluid of unwant ed solids by diverting the solid along with the main portion of the drilling fluid through the motor and through and out of the drill bit. The entry of large contaminating solids or high-density and abrasive solids to the bearings is restricted. This prevents plugging of flow through the bearings and reduces wear in the bearings by reducing the volume of abrasive solids.