Sealed eccentric drive for submersible pump

A well pump assembly, comprising:

• a pump having a pump drive shaft;
• an electrical motor having a motor drive shaft that rotates on a motor axis;
• an eccentric drive unit, comprising:
• an eccentric member operably coupled between the motor drive shaft and the pump drive shaft, the eccentric member having an offset portion parallel to and offset from the motor axis that orbits around the motor axis;
• a flexible boot enclosing the offset portion;
• a pump end static seal that seals a pump end of the boot at an interface between the eccentric member and the pump drive shaft;
• a motor end static seal that seals a motor end of the boot at a motor end of the eccentric member;
• a motor fluid communication path into the eccentric drive unit that communicates lubricant from the motor to an interior of the boot;
• and
• a well fluid communication path into the eccentric drive unit that communicates an exterior of the boot with well fluid.

A well pump assembly comprising:

• a pump having a pump drive shaft;
• an electrical motor having a motor drive shaft that rotates on a motor axis, the motor being filled with a motor lubricant;
• a motor end adapter having a motor shaft passage that rotatably receives a portion of the motor drive shaft;
• a pump end adapter having a pump shaft passage that rotatably receives a portion of the pump drive shaft;
• a housing secured between the motor end adapter and the pump end adapter;
• a crank throw portion on the motor drive shaft within the housing;
• a socket member on the pump drive shaft within the housing for rotation with the pump drive shaft, the socket member having a receptacle with an offset axis offset from and parallel to the motor axis for orbital movement around the motor axis;
• an offset portion of the motor drive shaft extending from the crank throw portion into the receptacle;
• a flexible boot enclosing the offset portion, the boot having a motor end sealed to the motor end adapter and a pump end that is sealed at an interface between the offset portion and the receptacle;
• a motor fluid communication path through the motor end adapter into an interior of the boot;
• and
• a well fluid communication path into the housing to communicate well fluid to an exterior of the boot.

A well pump assembly comprising:

• a motor end adapter having a motor shaft passage on a motor axis;
• a pump end adapter having a pump shaft passage on the motor axis;
• a housing secured between the motor end adapter and the pump end adapter;
• a motor drive shaft end portion extending rotatably through the motor shaft passage;
• a crank throw portion on the motor drive shaft end portion;
• a pump drive shaft end portion extending rotatably through the pump shaft passage, the pump drive shaft end portion having a receptacle with an offset axis offset from and parallel to the motor axis for orbital movement around the motor axis;
• an offset portion extending from the crank throw portion and having a receptacle end that extends into the receptacle, the offset portion being parallel to and offset from the motor axis;
• a cap on the receptacle end of the offset portion, the cap having a side wall and a closed end, the receptacle end of the offset portion being rotatable relative to the cap, the cap being inserted into the receptacle, the receptacle being rotatable relative to the cap;
• a flexible boot having a fixed end sealingly secured to the motor end adapter and an orbital end sealingly secured to the cap, enabling the cap to orbit about the motor axis without rotation relative to the fixed end of the boot;
• a motor fluid communication path through the motor end adapter into an interior of the boot and an interior of the cap for communicating lubricant to the interior of the boot;
• and
• a well fluid communication path into the housing to communicate well fluid to an exterior of the boot.