COLLET COUPLING FOR ELECTRIC SUBMERSIBLE PUMP SHAFTS

A collet coupling for electric submersible pumps is provided. An example coupling for joining two shafts includes a tubular coupling member, and collet for fixing the coupling to a shaft via expandable fingers with ribs for latching into a groove on each shaft. Shoulders in the groove transmit axial load forces between the two shafts through the ribs, fingers, and collet. An example method includes attaching one end of the coupling to a shaft of an ESP unit already installed in a well, adjusting an axial reach of a threaded collet for attachment to a second shaft of an upper ESP unit, and engaging ribs of the collet into a groove of the second shaft to couple the two shafts. A sliding retainer allows quick release. An axial deviation distance may be factory-stamped on the ESP units for quick length adjustment and installation of collet couplings in the field.