A submersible motor used in conjunction with a submersible pump used as a deep well pump is generally limited in size, particularly with respect to its horizontal sectional area, due to the limited diametral dimension of such deep well. In such application of the motor for a deep well submersible pump, the axial length of the whole submersible-motor deep well pump is made relatively long to provide the required capacity. In this case, the motor is generally disposed in the lowermost position and a pump is attached above the motor through a motor shaft extending upwardly from the motor.
Accordingly, the lowermost portion of the motor shaft is required to be rotatably supported by bearing means with respect to the radial load as well as the thrust load. Therefore, it has been necessary to employ a radial bearing and a thrust bearing independently. Thus, the axial length of the lower bearing portion is also made relatively long because of the dimensional limitation with regard to the diameter of the motor.
It has been desired to have a submersible motor having a shortened axial length without enlarging the lateral diameter of the motor housing.
USPTO Backgrounds
USPTO Backgrounds