SPINDLE OIL-FILLED SECTION OF HYDRAULIC DOWNHOLE MOTOR Russian patent published in 2012 - IPC E21B4/02 

FIELD: engines and pumps.

SUBSTANCE: proposed section consists of interconnected slidable tubular case and hollow shaft. Tubular case is made up of threaded tubular elements. Hollow shaft is made up of threaded hollow elements running in front and rear axial thrust bearings and fron and rear radial plane bearings. Mud fluid is forced through hollow shaft. Shaft front threaded hollow element has thread for bit. From seal module is arranged between front threaded tubular element and shaft fron threaded hollow element on bit thread side. Annular slidable piston with inner and outer seals is arranged between case and shaft. Tight oil chamber is made between front seal module, annular piston, case and shaft, while annular piston isolates tight oil chamber from that filled with mud fluid. Besides, it comprises extra threaded tubular element of the case that incorporates in-motor plain bearing arranged between front and rear thrust bearings. Shaft front hollow threaded element shank with bit thread is connected with said plain bearing. Fishing nut with front and rear thrust end is arranged between front thrust bearing end and shaft front threaded hollow element end on thread of the latter. Diameter of said nut exceeds that of front radial plain bearing. Note here that annular piston is arranged between its radial plain bearing and rear plain bearing to make unloading chamber filled with mud fluid. Holes are made in case threaded tubular element for discharging a portion of mud fluid via rear radial plain bearing radial gap and unloading chamber from the case.

EFFECT: higher reliability, longer life.

4 cl, 6 dwg