DOWNHOLE MOTOR TWO-HINGE PROPELLER SHAFT Russian patent published in 2010 - IPC E21B4/02 

FIELD: engines and pumps.

SUBSTANCE: proposed propeller shaft comprises drive and driven hinges each made up of case and half-shaft locked against mutual turn by balls arranged in the case and half-shaft grooves and holes, main and extra annular thrust plain bearings comprising thrust bearings fitted in the case and thrusts coupled with the shaft. Working contact surfaces of said thrusts are spherical. It comprises also flexible boot and case nut to isolate hinge oil-filled cavity. Note here that thrust bearing contact surfaces and those of additional annular bearing thrust represent sphere fragments. Note also that radius of additional bearing sphere exceeds that of the main bearing sphere.

EFFECT: invention using larger-size half-shaft and stronger balls, and fitting additional thrust bearing and additional packing seal on working surface.

2 cl, 2 dwg