Abstract:
A submersible pump motor has rotor sections spaced apart from each other with bearings located between. The bearings support the shaft of the rotor within a stator. The bearing is stationary and has a cavity in its outer periphery. A metallic coiled member is positioned along the circumference of the bearing, and rests in the cavity on the outside diameter of the bearing. The coiled member engages the bearing and the inner wall of the stator to prevent rotation of the bearing.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates in general to submersible pump motors, and in particular to a bearing assembly which resists rotation. The bearing assembly supports the shaft in the motor. 
   2. Description of the Prior Art 
   A submersible pump is a centrifugal pump having a submersible motor that rotates the shaft to drive the pump. The motors for high volume oil and water production may be from six to sixty feet in length and be rated at several hundred horsepower. Each motor has a stator secured within a tubular housing. The stator is made up of thin disks, called laminations, that are magnetic and insulated from each other by coatings. Windings extend through the laminations to the stator. 
   A rotor secured to a shaft rotates within the stator. Because of the long length, the rotor is made up of a number of rotor sections. Each rotor section comprises a large number of flat metal disks, called laminations, that are secured by copper rods. The disks are insulated from each other by coatings. The rotor sections are spaced apart from each other, and a bearing assembly is located between each rotor section to maintain the shaft in axial alignment. The rotor sections are keyed to the shaft for rotation with the shaft, but are axially movable with respect to the shaft. 
   Each bearing assembly includes a sleeve keyed to the shaft for rotation. A bearing body fits slidingly on the sleeve. An elastomeric ring encircles the bearing body, acting as a bearing member. The motor is filled with oil, causing the elastomeric ring to expand and frictionally engage the inner wall of the stator. This engagement prevents the bearing body from rotating and supports the shaft in alignment. 
   As the motor heats up to operating temperature, the bearing body will expand slightly outward. Also, the shaft will likely grow longitudinally, causing the bearing body to move longitudinally with respect to the stator. Therefore, the bearing body must be precisely dimensioned so that it does not engage the stator wall so tightly as to create excessive thrust loads on thrust washers located above and below the bearing assembly. Also, the elastomer material used to construct the bearing member must be carefully designed so that the swelling due to oil in the motor is the correct amount. 
   SUMMARY OF THE INVENTION 
   The present invention involves a coiled member placed in a cavity formed in the outside diameter of the bearing body. The purpose is to maintain contact between the bearing body and the stator inner wall, which prevents rotation of the bearing body and stabilizes the shaft. In the preferred embodiment, the coiled member is metallic. This broadens the operating uses of the bearing member since the bearing member will not be restricted by variability and temperature limitations of other materials, nor by the swelling limitations due to submergence in oil. The coiled member may be comprised of a continuous coiled member, connected end-to-end to form a single ring. Alternatively, the coiled member may be comprised of more than one coiled member segment. These multiple coiled member segments can be connected end-to-end with straight wire sections between them to form a single ring that sits in the cavity encircling the entire bearing body. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a partial, vertical sectional view of an electrical motor having a bearing assembly constructed in accordance with this invention. 
       FIG. 2  is an enlarged sectional view of the bearing member in the bearing cavity of  FIG. 1 . 
       FIG. 3  is a cross sectional view of the rotor and bearing member demonstrating the fall bearing member adapted to encircle the entire bearing body. 
       FIG. 4  is a cross sectional view of the rotor and bearing member demonstrating the partial bearing member segments adapted to contact the bearing body only partially. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIG. 1 , motor  11  includes a cylindrical housing  13 . A stator  15  is rigidly mounted within the housing  13 . The stator  15  is made up of a large number of flat magnetic disks, called laminations, having slots through which wires (not shown) are wound in a conventional manner. All the disks of the stator  15  are of magnetic steel. The disks of the stator  15  may be insulated from each other by coatings in a conventional manner. The stator  15  has a cylindrical inner wall  17  that is of uniform constant diameter. 
   A rotor is rotatably mounted within the inner wall  17  of the stator  15 . The rotor is comprised of a shaft  19  and a large number of metallic disks or laminations. The laminations are divided into identical rotor sections  21  approximately fifteen inches in length. A portion of two rotor sections  21  is shown in  FIG. 1 . Each rotor section  21  has an outer wall  23  that is closely spaced to the inner wall  17  of the stator  15 . Each rotor section  21  is secured by copper rods (not shown), with copper end rings  25  on both sides. The ends of the copper rods are brazed or mechanically welded to the end rings  25  to hold the laminations in each rotor section  21  together. 
   Each rotor section  21  is secured by a key (not shown) to the shaft  19  for rotation therewith. The sections of the rotor  21  are not individually axially locked to the shaft  19 . However, the lowermost section of rotor  21  at the end of the shaft  19  is axially locked to support the sections of the rotor  21  with respect to the shaft  19 . Also, the uppermost section of the rotor  21  will be axially locked to the shaft  19 . 
   A bearing assembly is located between each of the rotor sections  21 . The bearing assembly includes a sleeve  27  that is secured to shaft  19  for rotation therewith by means of a key (not shown). Sleeve  27  is preferably a bronze cylinder and is not axially locked to shaft  19 . The upper edge or circular rim of sleeve  27  contacts the lowermost lamination of the section of rotor  21  directly above, and the lower edge of sleeve  27  contacts the uppermost lamination of the section of rotor  21  directly below. Therefore, the sleeve  27  supports the weight of the rotor sections  21  above and transmits any downward force on rotor sections  21  above to the next lower rotor section  21 . 
   A bearing body  29  has a hub or inner portion  31  that is located within the inner bore of each end ring  25 , with a clearance between the end ring  25  inner diameter and the hub  31  outer diameter. Hub  31  is cylindrical and has less length than sleeve  27 . Hub  27  is preferably of steel, and may be magnetic. 
   A thrust washer  33  is located around the outer diameter of sleeve  27  and between the section of rotor  21  directly above and the upper edge of hub  31 . A similar thrust washer  33  is located between the lower edge of hub  31  and the rotor section  21  directly below. Thrust washers  33  are preferably of a non-metallic material, such as glass reinforced phenolic material. The distance from the lower side of the lower thrust washer  33  to the upperside of the upper thrust washer  33  is about 1/32 inch less than the height of sleeve  27 . This prevents the thrust washers  33  from supporting the weight of the rotor sections  21  located above. 
   Bearing body  29  has a flange or outer portion  35  that extends radially outward from hub  31 . Outer portion  35  has a cylindrical periphery  37  that is spaced inward from the inner wall  17  of stator  15  by a clearance of about 0.003 to 0.005 inch on the diameter. The longitudinal thickness or height of the outer portion  35  is less than the distance between the two adjacent end rings  25 . A plurality of passages  39  extend through the outer portion  35  for communicating oil contained within the housing  13 . Bearing body  29  is normally of a metallic material, preferably nitralloy. 
   Referring to  FIG. 2 , the cylindrical periphery  37  of the bearing body  29  outer portion  35  has an annular groove or cavity  41  extending circumferentially around bearing body  29  perpendicular to the axis of shaft  19 . Cavity  41  is preferably rectangular in cross-section. A coiled member  45  is recessed within the cavity  41 . The space occupied by the coiled member  45  forms a toroid. The coiled member  45  is metallic, preferably of spring steel. The coiled member  45  is sized to fit inside of the cavity  41  and maintain contact with both bearing body  29  and the inside wall  17  of the stator  15 , thus the coils of coiled member  45  have a diameter greater than the radial extent of cavity  41 . The coil member  45  may have a circular cross-section (as shown) or perhaps a square, rectangular, triangular, or other suitable cross-section. A centerline  47  extends through the coils of coiled member  45 . The centerline  47  is a circumferential line with a radius relative to the axis of shaft  19 . The radius of the centerline  47  is less than the radius of the cylindrical periphery  37  of the outer portion  35  of the bearing  29 . In the undeflected condition, the coiled member  45  has a diameter that is greater than the radial depth of the cavity  41  so that an outer portion protrudes past the cylindrical periphery  37  of the bearing body  29 . The diameter of the coiled member  45  is selected so that an outer portion of the coiled member  29  will contact inner wall  17  of stator  15  and deflect. The stiffness of the coiled member  45  is selected so that coiled member  45  will grip inner wall  17  of stator  15  with sufficient force to prevent bearing  29  from spinning with the shaft  19 . 
   Referring to  FIG. 3 , the coiled member  45  may be a continuous spring element, stretched around the circumference of the bearing cavity  41  with its ends connected together (as shown). Alternatively, in  FIG. 4 , the coiled member  45 ′ may be non-continuous about the circumference of the bearing cavity  41 . A plurality of coiled member segments  45 ′ may be spaced apart from each other around the circumference of cavity  41 . One embodiment employs three coil element segments  45 ′ spaced equally apart (as shown) to provide three points of support at 120 degrees spacing around the inside diameter  37  of stator  15 . Coiled member segments  45 ′ can be connected end-to-end with straight wire sections between them to form a single ring. 
   During assembly, coiled member  45  is inserted into the bearing body cavity  41 . The sleeve  27  and bearing body  29  are assembled upon the shaft  19  between rotor sections  21 . Then the rotor is inserted into the stator  15 , with coiled member  45  radially deflecting as it slides past the laminations of stator  15 . Housing  13  is filled with oil, which does not cause swelling of coiled member  45 . The coiled member  45  continues to be engaged in contact with the bearing body cavity  41  and stator inner wall  17 . In operation, sleeve  27  will rotate with the hub  31 . The frictional engagement due to deflection of coiled member  45  prevents bearing body  29  from spinning with shaft  19 . Heat will cause the rotor sections  21  to expand longitudinally, while stator  15  is prevented from the same axial expansion. The resilient nature of the coiled member  45  allows some axial movement of rotor sections  21  relative to stator  15  to accommodate this expansion. 
   The invention has significant advantages. The coiled member arrangement allows easy insertion of the rotor into the stator  15  yet stops the bearing body  29  from spinning once the motor begins operation. The metallic coiled member  45  has advantages over elastomeric T-rings used in other systems in that it is not limited by he temperature limitations and variability of the elastomer. The coiled member  45  centers the bearing body  29  within the stator  15  bore and provides good radial support. 
   While this invention has been shown in only two of its forms, it should be apparent to those skilled in the art that it is not so limited but is susceptible to various changes without departing from the scope of the invention.