Patent Publication Number: US-2018034341-A1

Title: Submersed electric motor and method for providing such a submersed electric motor

Description:
The present invention relates to a submersed electric motor. 
     The invention also relates to a method for providing such a submersed electric motor. 
     Corresponding submersed electric motors are currently known and used extensively for the actuation of submersed pumps. 
     One widespread type of submersed motor comprises: 
     a stator assembly arranged inside an annular chamber, comprising stator windings,
 
the annular stator chamber is formed between an outer tubular jacket, an inner tubular jacket, which is coaxial to said outer tubular jacket, with two annular end covers which are adapted to close the annular interspace between said outer jacket and inner jacket, said interspace being filled with insulating resin adapted to embed all the electrical elements that are contained in the latter; the resin, in addition to providing electrical insulation, is adapted to facilitate the external transmission of the generated heat and to give strength to the motor in case of deep immersions and therefore high pressures;
 
a rotor, with a rotation shaft, arranged inside said inner tubular jacket.
 
     The submersed motor normally comprises an electrical plug which is adapted for connection to an external system, i.e., an outlet with a cable, for electric power supply. 
     Although these motors are widespread and appreciated, they have some aspects that allow improvement, linked to the integration of said plug in one of the two covers of the annular chamber. 
     Such plug is in fact currently provided by co-molding a plastic connecting part on contact terminals, which are constituted for example by turned metallic elements, and on the corresponding wires soldered thereto. 
     This plastic connecting part is fixed to a corresponding contoured flange by means of screws, said flange being present to be locked between the outer and inner tubular jackets and a corresponding annular end cover. 
     The flange then has a seat which is extended in an axial direction, i.e., parallel to the longitudinal axis of the submersed motor, for accommodating the outlet system connected to the power supply cable, the seat having, at its bottom, the plastic connecting part. 
     The flange is shaped in a particular manner and is therefore expensive. 
     Furthermore, the electrical connection system as a whole requires a plurality of operations for the assembly of components, which affect the overall cost of the motor. 
     The aim of the present invention is to provide a submersed electric motor that is capable of obviating the cited limitations of submersed motors of the known type. 
     Within this aim, an object of the present invention is to provide a submersed motor the electric power supply connection system of which is simpler from the point of view of componentry. 
     Another object of the present invention is to provide a submersed motor the electrical connection of which has an efficiency and strength that are not lower than those of known submersed motors. 
     A further object of the present invention is to provide a method for providing a submersed motor according to the aim. 
     This aim, as well as these and other objects which will become better apparent hereinafter, are achieved by a submersed electric motor according to claim  1  and by a method for providing it according to claim  3 . 
    
    
     
       Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment of the submersed electric motor according to the invention, illustrated by way of nonlimiting example in the accompanying drawings, wherein: 
         FIG. 1  is a sectional side view of a portion of a submersed electric motor according to the invention; 
         FIG. 2  is a perspective view of a detail for the provision of a motor according to the invention; 
         FIG. 3  is a sectional side view of the detail of  FIG. 2 , inserted in the motor according to the invention; 
         FIG. 4  is a view of a step of the provision of a motor according to the invention; 
         FIG. 5  is a view of another step of the provision of a motor according to the invention. 
     
    
    
     With reference to the figures, a submersed electric motor according to the invention is designated generally by the reference numeral  10 . 
     The submersed electric motor  10  comprises:
         a stator assembly  11  arranged inside an annular stator chamber  12 ,   the annular stator chamber  12  being formed between an outer tubular jacket  13 , an inner tubular jacket  14  which is coaxial to said outer tubular jacket, with two annular end covers, of which one cover  15  is shown in  FIG. 1 , which are adapted to close the annular interspace between the outer jacket and the inner jacket; the annular stator chamber  12  contains zo solid insulating resin  16  adapted to embed the electrical elements contained in the annular stator chamber  12 ;   a rotor  17 , with a rotation shaft  18 , arranged inside the inner tubular jacket  14 ,   an electrical connector  19 , for example a plug, adapted for connection to a outlet  20  with an electric power supply cable  21 .       

     The particularity of the invention resides in that the electrical connector  19  comprises electrical terminals  22  for the electrical connection of the stator assembly  11 , which are arranged so as to protrude from the solid resin  16 , surrounded by walls  23  of the solid resin  16  which form a seat  24  for a power outlet, which is open onto a through hole  25  formed in an annular end cover  15 . 
     The submersed motor  10  therefore comprises an electrical connector  19 , for example a plug, which does not have the plastic connecting part molded onto the contact terminals, its absence eliminating the operations for fixing to a contoured flange in order to accommodate the power supply outlet. 
     The submersed motor  10  in any case comprises a flange  28  that is locked between the outer tubular jacket  13  and the inner tubular jacket  14 , and the corresponding annular end cover  15 . 
     The absence of said plastic part to be fixed allows the provision of a flange  28  that is simpler and therefore cheaper. 
     The invention also relates to a method for providing such a submersed electric motor. 
     The provision of a submersed electric motor according to the invention in fact comprises the following steps: 
     assembling the stator assembly  11  with the corresponding electrical terminals  22  in the annular stator chamber  12  between the inner and outer tubular jackets,
 
assembling at one end of the annular stator chamber  12  a flange  28  provided with a through hole  29 , which has an axial direction, i.e., parallel to the main axis of the motor,
 
inserting the through hole  29  an insert  30  for the shaping in the solid resin  16  of the  24  for an electrical outlet  20 , the insert  30  being contoured to cover and retain in position the terminals  22  and to obstruct the through hole  29 ,
 
filling the annular chamber  12  with fluid resin,
 
upon the solidification of the resin  16 , extracting the insert  30 , freeing the terminals  22  inside the seat  24 .
 
     The insert  30  is clearly visible in  FIG. 2 ; in this constructive exemplary embodiment, which does not limit the invention, the insert  30  is constituted by a cup-like cylindrical body  31  with a number of tubular terminal protection channels  32  that matches the number of electrical terminals  22  to be retained in position and to be protected during the pouring of the resin; the insert  30  is provided with a shoulder  33  for resting on the edge of the through hole  29 . 
     Obviously, the radial dimension of the cup-like body  31  is such as to obstruct the through hole  29  on the flange  28 , as clearly visible in  FIG. 3 . 
       FIG. 4  is a view of the step of placement of the flange  28  with the insert  30  in the through hole  29  before pouring the resin. 
       FIG. 5  shows the step of removing the insert  30 , freeing the terminals  22  in the seat  24 . 
     In practice it has been found that the invention achieves the intended aim and objects. 
     In particular, the invention provides a submersed motor the electric power supply connection system of which is simpler from the point of view of components and assembly. 
     Furthermore, the invention provides a submersed motor the electrical connection of which has an efficiency and strength that are not lower than those of known submersed motors. 
     Moreover, the invention provides a method for providing such a submersed motor. 
     The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may further be replaced with other technically equivalent elements. 
     In practice, the components and the materials used, so long as they are compatible with the specific use, as well as the contingent shapes and dimensions, may be any according to the requirements and the state of the art. 
     The disclosures in Italian Patent Application No. 102016000078029 (UA2016A005478) from which this application claims priority are incorporated herein by reference.