Well drilling apparatus

Claim 1

A WELL DRILLING ASSEMBLY COMPRISING A MOTOR CASING SECTION ADAPTED TO BE SECURED TO THE LOWER END OF A STRING OF DRILL PIPE, A CONNECTING ROD CASING SECTION SECURED TO THE LOWER END OF SAID MOTOR CASING SECTION, AND A BEARING CASING SECTION SECURED TO THE LOWER END OF SAID CONNECTING ROD CASING SECTION, A HYDRAULIC MOTOR ADAPTED TO BE DRIVEN BY A STREAM OF FLUID UNDER PRESSURE COMPRISING A STATOR OF RESILIENT MATERIAL BONDED WITHIN SAID MOTOR CASING SECTION AND HAVING A DOUBLE INTERNAL HELICAL THREAD, A RADIAL BEARING MOUNTED IN SAID BEARING CASING SECTION, SAID BEARING CASING SECTION HAVING AN INTERNAL ANNULAR SHOULDER NEAR ITS LOWER END, A HOLLOW DRILL SHAFT DISPOSED WITHIN SAID BEARING CASING SECTION FOR ROTATION IN SAID RADIAL BEARING, A HOLLOW BIT SUB SECURED TO THE LOWER END OF SAID DRILL SHAFT AND PROVIDING AN ANNULAR SHOULDER, A THRUST BEARING SURROUNDING SAID DRILL SHAFT BETWEEN SAID SHOULDERS WITH SUBSTANTIAL LONGITUDINAL PLAY, MEANS FOR INTRODUCING THE FLUID FROM SAID MOTOR INTO SAID THRUST BEARING, SAID BEARING CASING SECTION AT ITS UPPER END PROVIDING A SHOULDER, A RETAINING RING SECURED TO SAID DRILL SHAFT ADJACENT ITS UPPER END, A THRUST BEARING SURROUNDING SAID DRILL SHAFT BETWEEN SAID LAST NAMED SHOULDER AND SAID RETAINING RING WITH SUBSTANTIAL LONGITUDINAL PLAY, MEANS FOR INTRODUCING THE FLUID FROM SAID MOTOR INTO SAID LAST NAMED THRUST BEARING, SAID THRUST BEARINGS EACH COMPRISING AN UPPER AND A LOWER RACE, AND A SERIES OF BALLS THEREBETWEEN, SAID RACES BEING PROVIDED WITH BALL GROOVES AND BEING FREE OF BALL CAGES, WHEREBY SAID RACES MAY MOVE RELATIVE TO EACH OTHER WITHIN THE AREA OF LONGITUDINAL CONFINEMENT, SAID BEARINGS THEREBY BEING CAPABLE OF PURGING THEMSELVES OF FOREIGN PARTICLES, A METALLIC ROTOR HAVING A SINGLE HELICAL THREAD DISPOSED IN OPERATIVE RELATIONSHIP WITHIN SAID STATOR, AND A CONNECTING ROD CONNECTING SAID ROTOR AND DRILL SHAFT, WHEREBY THE MOTOR ROTOR, CONNECTING ROD, DRILL SHAFT AND BIT SUB, AS A UNIT, MAY MOVE A SUBSTANTIAL DISTANCE LONGITUDINALLY OF SAID STATOR AND CASING SECTION, WITH ONE OF SAID THRUST BEARINGS BEING OPERATIVE TO TAKE THE THRUST IN ONE DIRECTION AT ONE LIMIT OF SUCH MOVEMENT, AND THE OTHER OF SAID THRUST BEARINGS BEING OPERATIVE TO TAKE THE THRUST IN THE OPPOSITE DIRECTION AT THE OTHER LIMIT OF SUCH MOVEMENT.