Patent Publication Number: US-2023134351-A1

Title: Two-piece end turn winding support

Description:
BACKGROUND 
     The present disclosure relates to electric machines and, more particularly, to an electric motor-generator with a two-piece end turn winding support. 
     A typical electric machine includes a rotor and a stator surrounding the rotor with an air gap defined between an outer diameter of the rotor and an inner diameter of the stator. The rotor can include radially outwardly extending teeth with one or more conductive windings wound thereon. The stator can include a set of permanent magnets or electro-magnets disposed about the rotor. When current is applied to the conductive windings, the current generates a flux field that interacts with the permanent magnets or the electro-magnets of the stator to cause the rotor to rotate about a rotational axis thereof. Alternatively for an electric generator, rotation interacts with the field and produces a current. 
     As the conductive windings are wound on the teeth of the rotor, the conductive windings can be provided with end turns at axial ends of the rotor. The end turns allow the conductive windings to be repeatedly wound back and forth on the rotor. End winding supports can be provided to support the end turns. 
     It has been found that with some configurations, the end winding supports experience unacceptably high levels of stress and that this stress can lead to fractures in some cases. While material strength of the end winding supports can be increased, this is either an expensive solution or results in end winding supports that do not meet the functional requirement that they be electrically non-conductive. 
     BRIEF DESCRIPTION 
     According to an aspect of the disclosure, an end winding support of a rotor of an electric machine is provided. The end winding support includes a first part and a second part. The first part includes an elongate body about which a conductive winding is wound. The elongate body has a surface defining a first groove. The second part is attached to the first part. The second part includes a body which extends outwardly from the elongate body and which has a surface defining a second groove corresponding to the first groove. 
     In accordance with additional or alternative embodiments, the second part extends beyond an outboard portion of the first part. 
     In accordance with additional or alternative embodiments, the second part further includes a curved radially outwardly facing surface. 
     In accordance with additional or alternative embodiments, the second part is press-fit to the first part. 
     In accordance with additional or alternative embodiments, the first groove widens around a recess into a widened section at an inboard portion of the first part. 
     In accordance with additional or alternative embodiments, the widened section of the first groove is receptive of a busbar and the recess is engaged with a fastening element to secure the busbar in the widened section of the first groove. 
     In accordance with additional or alternative embodiments, a fitting is interposable between the fastening element and an interior surface of the recess. 
     According to an aspect of the disclosure, a rotor of an electric machine is provided. The rotor includes a rotor assembly having multiple poles, a conductive winding, which is wound around one or more of the multiple poles and an end winding support to support the conductive winding. The end winding support includes a first part and a second part. The first part includes an elongate body about which the conductive winding is wound. The elongate body has a surface defining a first groove. The second part is attached to the first part. The second part includes a body which extends outwardly from the elongate body and which has a surface defining a second groove corresponding to the first groove. 
     In accordance with additional or alternative embodiments, a containment band is disposed radially about the rotor assembly and in abutment with the second part. 
     In accordance with additional or alternative embodiments, the second part extends outwardly beyond an outboard portion of the first part in circumferential and axial directions of the rotor assembly. 
     In accordance with additional or alternative embodiments, the second part further includes a curved radially outwardly facing surface. 
     In accordance with additional or alternative embodiments, the second part is press-fit to the first part. 
     In accordance with additional or alternative embodiments, the first groove widens around a recess into a widened section at an inboard portion of the first part. 
     In accordance with additional or alternative embodiments, a busbar, is configured to be seated within the widened section of the first groove and a fastening element is engageable with the recess to secure the busbar in the widened section of the first groove. 
     In accordance with additional or alternative embodiments, a fitting is interposable between the fastening element and an interior surface of the recess. 
     In accordance with additional or alternative embodiments, the first and second grooves cooperatively provide space between the conductive winding and the first and second parts, respectively. 
     According to an aspect of the disclosure, a rotor assembly method is provided and includes installing a first part of a winding support in a rotor assembly, winding a conductive winding about the first part or around a pole of the rotor assembly with the first part used to take up slack in the conductive winding and attaching a second part to the first part, the second part extending outwardly from the first part. 
     In accordance with additional or alternative embodiments, the method further includes winding the conductive winding about one or more of multiple poles of the rotor assembly. 
     In accordance with additional or alternative embodiments, the attaching includes press-fitting the second part to the first part. 
     In accordance with additional or alternative embodiments, the method further includes arranging a containment band about the rotor assembly and in abutment with the second part. 
     Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed technical concept. For a better understanding of the disclosure with the advantages and the features, refer to the description and to the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts: 
         FIG.  1    is a schematic side section view of an electric machine in accordance with embodiments; 
         FIG.  2    is a radially inward view of a portion of a rotor assembly of an electric machine including end winding supports in accordance with embodiments; 
         FIG.  3    is an enlarged side section view of a portion of a rotor assembly of an electric machine including an end winding support in accordance with embodiments; 
         FIG.  4    is a perspective view of an end winding support of  FIGS.  3  and  4    in accordance with embodiments; 
         FIG.  5    is a flow diagram illustrating a rotor assembly method in accordance with embodiments; and 
         FIG.  6    is a flow diagram illustrating a rotor assembly method in accordance with alternative embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     As will be described below, end winding supports are provided for use in electric machines to support conductive windings on rotors. The end winding supports are each split into two parts along a line where end winding support fracturing is likely to occur. As a result, stress or strain that is otherwise experienced by conventional end winding supports is not transmitted to either of the two parts in the same way and failure can be avoided. 
     With reference to  FIGS.  1  and  2   , a rotor  101  of an electric machine  100  is provided. As shown in  FIGS.  1  and  2   , the electric machine  100  includes the rotor  101 , which is rotatable about a rotational axis A thereof and a stator  102 . The stator  102  surrounds the rotor  101  and includes permanent- or electro-magnets  103 . The rotor  101  includes a rotor assembly  110  having multiple poles  111 , conductive windings  120 , each of which is wound around one or more of the multiple poles  111  and end winding supports  130 . The conductive windings  120  can be preformed. Each of the end winding supports  130  can be located at or near to one of the multiple poles  111  at either end of the rotor assembly  110  and is configured to support a corresponding end turn  121  of a corresponding one of the conductive windings  120 . During an operation of the electric machine  100 , current is applied to the conductive windings  120  and causes the rotor  101  to either rotate about the rotational axis A by interactions with a flux field generated by the permanent- or electro-magnets  103  or if rotating already to generate current in the electro-magnets of stator  102 . 
     The rotor  101  can further include containment bands  140 . The containment bands  140  are disposed radially about the rotor assembly  110  and can be provided with tabs  141  (see  FIG.  3   ) that are disposed in abutment with a curved radially outwardly facing surface  131  (see  FIG.  3   ) of each of the end winding supports  130 . 
     With continued reference to  FIG.  2    and with additional reference to  FIGS.  3  and  4   , each end winding support  130  includes a first part  310  and a second part  320 . The first part  310  includes an elongate body  311  that has a surface  312  formed to define a first groove  313 . The second part  320  can be attached or press-fit to the first part  310  and includes a body  321  which extends outwardly from an outboard portion of the elongate body  311  of the first part  310  in circumferential and axial directions of the rotor assembly  110  (see  FIG.  4   ). The second part  320  has a surface  322  formed to define a second groove  323  which corresponds in position to the first groove  313 . 
     When an end winding support  130  is installed in the rotor assembly  110  of  FIG.  1    at or near to one of the multiple poles  111 , corresponding ones of the conductive windings  120  are stacked radially as shown in  FIG.  1    and wound around the end winding support  130  as shown in  FIG.  2   . More particularly, each conductive winding  120  extends along a longitudinal length L (see  FIG.  2   ) of the rotor assembly  110  and is wound around the first part  310  of the end winding support  130 . In accordance with embodiments, the first groove  313  and the second groove  323  are formed and configured to cooperatively create space between each of corresponding ones of the conductive windings  120  and the end winding support  130  for lubricant (e.g., oil) flow and/or for winding connections. 
     In accordance with embodiments and as shown in  FIG.  4   , the first groove  313  can be formed to widen around a recess  314  into a widened section  315  at an inboard portion of the elongate body  311  of the first part  310 . As shown in  FIG.  3   , the rotor  101  can also include a busbar  330  configured to be seated within the widened section  315  and a fastening element  331 , which is engageable with the recess  314  to secure the busbar  330  in the widened section  315 . In addition, the rotor  101  can include a fitting  332 , which is interposable between the fastening element  331  and an interior surface of the recess  314 . 
     With reference to  FIG.  5   , a rotor assembly method is provided for assembling the rotor  101  and the rotor assembly  110  described herein. As shown in  FIG.  5   , the rotor assembly method includes installing a first part of a winding support in a rotor assembly ( 501 ), winding a conductive winding about the first part ( 502 ) by, e.g., winding the conductive winding about one or more of multiple poles of the rotor assembly, and attaching a second part to the first part ( 503 ) where the second part extends outwardly from an outboard portion of the first part by, e.g., press-fitting the second part to the first part. In accordance with embodiments, the rotor assembly method can further include arranging a containment band about the rotor assembly and in abutment with the second part ( 504 ). In accordance with additional embodiments, the rotor assembly method can also include preforming the conductive winding ( 505 ) prior to at least the winding of operation  502 . In some cases, the preforming can be executed prior to the installing of the first part of operation  501 . 
     With reference to  FIG.  6   , a rotor assembly method is provided for assembling the rotor  101  and the rotor assembly  110  described herein. As shown in  FIG.  6   , the rotor assembly method includes winding a conductive winding around a pole in a rotor assembly ( 601 ), installing a first part of a winding support in the rotor assembly to take up slack in the conductive winding ( 602 ) and attaching a second part to the first part ( 603 ) where the second part extends outwardly from an outboard portion of the first part by, e.g., press-fitting the second part to the first part. In accordance with embodiments, the rotor assembly method can further include arranging a containment band about the rotor assembly and in abutment with the second part ( 604 ). In accordance with additional embodiments, the rotor assembly method can also include preforming the conductive winding ( 605 ) prior to the winding of operation  601 . 
     Technical effects and benefits of the present disclosure are the provision of an end winding support of conductive windings of a rotor that is split into two parts and thus resists fracturing. Of these two parts, a first part can be easily installed whereupon the corresponding conductive winding can be more easily placed. Then, the second part can be attached or installed to complete the supporting function and transmit rotating forces to a containment band. As such, a part that would have been more difficult and expensive or prone to failure is provided as a more robust, simple and cost-effective subassembly. 
     The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the technical concepts in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. The embodiments were chosen and described in order to best explain the principles of the disclosure and the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated. 
     While the preferred embodiments to the disclosure have been described, it will be understood that those skilled in the art, both now and in the future, may make various improvements and enhancements which fall within the scope of the claims which follow. These claims should be construed to maintain the proper protection for the disclosure first described.