Abstract:
The present application provides a stator. The stator may include a number of poles and a stator tip and cooling assembly. The stator tip and cooling assembly may include a number of stator tips with a number of cooling tubes adjacent thereto such that the stator tips align with the poles and the cooling tubes cool the poles.

Description:
FEDERAL RESEARCH STATEMENT 
     This invention was made with Government support under Contract No. DE-FC26-07NT43122-GOVT, awarded by the US Department of Energy (DOE). The Government has certain rights in this invention. 
    
    
     TECHNICAL FIELD 
     The present application relates generally to electrical device components and more particularly relates to a stator with stator tooth tip cooling for use in an electrical motor or a generator and a method of assembling the same. 
     BACKGROUND OF THE INVENTION 
     Generally described, electrical devices such as motors and generators have a rotor that is coaxially positioned within a stator for rotation therewith about a shaft. Operational improvements in such electrical devices may focus at least in part on increasing the amount of current that may flow through the stator so as to increase the overall power density. 
     Increasing the current flow through the stator, however, also may increase the heat generated by the coils therein due to resistive or ohmic heating. Increased rotor speeds thus may lead to increased heat and temperatures. Of particular concern is the stator tooth tip region where a significant portion of the heat losses may be generated. Without sufficient cooling, increases in stator heat thus may limit increases in overall electrical power density. 
     There is a desire therefore for improved stator cooling systems and methods, particularly about the stator tooth tip region. Such cooling systems and methods should effectively cool the stator, especially at higher speeds, so as to allow for increases in overall power density. 
     SUMMARY OF THE INVENTION 
     The present application thus provides a stator. The stator may include a number of poles and a stator tip and cooling assembly. The stator tip and cooling assembly may include a number of stator tips with a number of cooling tubes positioned adjacent thereto such that the stator tips align with the poles and the cooling tubes cool the poles. 
     The present application further provides a method of assembling a stator. The method may include the steps of winding a number of coils about a number of teeth in a stack, positioning a stator tip and cooling assembly within the stack, and connecting a number of cooling tubes with a cooling manifold. The stator tip and cooling assembly may include a number of stator tips with the cooling tubes adjacent thereto such that the stator tips align with the teeth and the cooling tubes align with the coils. 
     The present application further provides an electrical device. The electrical device may include a rotor and a stator positioned about the rotor. The stator may include a number of poles and a stator tip and cooling assembly to cool the poles positioned adjacent thereto. 
     These and other features and improvements of the present application will become apparent to one of ordinary skill in the art upon review of the following detailed description when taken in conjunction with the several drawings and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an electrical device. 
         FIG. 2  is a perspective view of the electric device. 
         FIG. 3  is a perspective view of a stator lamination stack. 
         FIG. 4  is a perspective view of the stator lamination stack of  FIG. 3  with coils thereon. 
         FIG. 5  is a perspective view of a stator tip and cooling assembly. 
         FIG. 6  is a side view of a stator tooth. 
         FIG. 7  is a perspective view of the stator assembly with a first end shield. 
         FIG. 8  is a prospective view of the stator assembly with an outer cooling jacket thereon. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings, in which like numerals refer to like elements throughout the several views,  FIG. 1  shows a schematic view of a known electrical device  10 . The electrical device  10  may be an electric motor or a generator. The electrical device  10  may include a stator  20 , a rotor  30 , and a shaft  40 . The stator  20  generally may be annular in shape and may be fixed in place. The rotor  30  may be attached to the shaft  40 . The rotor  30  and the shaft  40  may be positioned within the stator  20  for rotation therein. Other configurations and other types of electrical devices may be used herein. 
       FIG. 2  shows an electrical device  100  as may be described herein. Similar to that described above, the electrical device  100  may include a stator  110  with a rotor  120  positioned therein on a shaft  130 . As will be described in more detail below, the stator  110  may include a number of poles  140 . The stator  110  in general and the poles  140  in particular may include a stator tip and cooling assembly  150 . The stator  110  also may include a cooling jacket  160  thereon. The stator tip and cooling assembly  150  and the cooling jacket  160  may be in communication with a cooling manifold  170  for the circulation of a cooling medium therein. Other configurations of the electrical device  100  and the stator  110  may be used herein. 
       FIGS. 3-8  show the components of the overall stator  110  and the stator tip and cooling assembly  150  in particular. Specifically,  FIG. 3  shows a lamination stack  180  as may be used herein. The lamination stack  180  may be in the form of a full loop for improved mechanical strength. The lamination stack  180  may have a number of teeth  190  extending from a yoke  200 . The teeth  190  may extend inwardly from the yoke  200  and may define a number of inner slots  210  therebetween. The yoke  200  also may define a number of outer slots  220  on an outside surface. Other lamination stack configurations may be used herein. 
       FIG. 4  shows the lamination stack  180  with a number of coils  230 . One of the coils  230  may be wrapped around each of the teeth  190 . The coils  230  may be electrically interconnected such that current is transferable therebetween. The coils  230  may largely fill the inner slots  210  between each tooth  190 . The combination of a tooth  190  and a coil  230  may be referred to herein as a pole  240 . Although twelve (12) poles  240  are shown, any number of the poles  240  may be used herein. Other configurations may be used herein. 
       FIG. 5  shows an example of the stator tip and cooling assembly  150 . The stator tip and cooling assembly  150  may include a number of tooth tips  250  separated by a number of epoxy spacers  260  so as to create a ring subassembly  270 . The tooth tips  250  may be sized according to the corresponding tooth  190  of the lamination stack  180 . The tooth tips  250  may be punched from laminations with a lamination index and the like. The tooth tips  250  and the epoxy spacers  260  may be arranged in a tongue and groove arrangement  280  as is shown in  FIG. 6 . The epoxy spacers  260  may be made out of an Al 2 O 3  impregnated epoxy or similar types of materials. Other configurations and other materials may be used herein. 
     The epoxy spacers  260  may include a number of cooling channels  290  therein such that a number of cooling tubes  300  may extend therethrough. One cooling tube  300  may encircle a tooth tip  250  about a tooth  190  such that a stator  110  with, for example, twelve (12) poles  240  may include six (6) cooling tubes  300 . The cooling tubes  300  may be in communication with the cooling manifold  170 . Other configurations may be used herein. 
     The combination of the lamination stack  180  with the coils  230  and the stator tip and cooling assembly  150  creates what may be called a stator subassembly  310 . When so positioned, the stator tip and cooling assembly  150  also holds the coils  230  of the lamination stack  180  in place.  FIG. 7  shows a first end shield  320  attached about one side of the stator subassembly  310 . 
       FIG. 8  shows the outer cooling jacket  160  positioned about the stator subassembly  310 . The outer cooling jacket  160  may be shrunk on to the lamination stack  180  or otherwise attached. No sacrificial rings thus may be required to maintain consistency given the rigid lamination stack  180 . As described above, the outer cooling jacket  160  may be in communication with the cooling manifold  170 . Other configurations may be used herein. A second end shield  330  may be positioned on the stator subassembly  310  so as to form a completed stator  110 . An additional amount of epoxy may be placed between the poles  240  and the stator tip and cooling assembly  150  to improve the conduction path therethrough. Other types of assembly methods may be used herein. 
     The stator  110  with the stator tip and cooling assembly  150  thus cools the poles  240  about the tooth tips  250 . As described above, a significant portion of heat may be generated about the tooth tip area. By cooling the tooth tips  250 , overall machine power density may be increased. Moreover, the stator tip and cooling assembly  150  effectively cools the overall stator  110 , especially at higher speeds. The ring subassembly  270  of the stator tip and cooling assembly  150  also integrates the tooth tips  250  and the cooling tubes  300  therein. 
     It should be apparent that the foregoing relates only to certain embodiments of the present application and that numerous changes and modifications may be made herein by one of ordinary skill in the art without departing from the general spirit and scope of the invention as defined by the following claims and the equivalents thereof.