Abstract:
A method of making a wound field for a brushless direct current motor, direct current generator, alternating current motor or alternating current generator, includes providing a base mold and a press mold. Next, a number of phases is determined. At least one strand of conductive material per phase is formed between the base mold and press mold into a conductive coil that has a shape that indicates the number of poles required. Each conductive coil is inserted into the stator core, and the stator core is installed into one of a brushless direct current motor, direct current generator, alternating current motor or alternating current generator.

Description:
[0001]    This application is a divisional of application Ser. No. 11/695,955, filed Apr. 3, 2007, entitled METHOD FOR WINDING BRUSHLESS DC MOTORS, the entire contents of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE PRESENT INVENTION 
       [0002]    The present invention relates to a method for making a winding for a motor or generator, and more specifically, a method for making a winding for an AC or DC brushless motor or generator. 
         [0003]    Slotless brushless DC motors are known for having performance advantages as compared to traditional motors and are used in many capacities from medical equipment to pumps. Conventional methods are to wind a separate coil or group of coils for each magnetic pole required. The lack of defined slots and teeth, however, make the winding process more difficult and expensive than typical brushless DC motors that include teeth and slots. 
         [0004]    Accordingly, a simplified winding method that requires only one coil per phase no matter how many poles are present in the motor is desired. 
       SUMMARY OF THE INVENTION 
       [0005]    In one aspect of the present invention, a method of making a wound field for a brushless direct current motor, direct current generator, alternating current motor or alternating current generator, includes providing a base mold and a press mold. Next, a number of phases is determined. At least one strand of conductive material is formed for each phase between the base mold and the press mold into a conductive coil that has a configuration that indicates the number of poles required. The formed conductive coil is inserted into a stator core, and the stator core is installed into one of a brushless direct current motor, direct current generator, alternating current motor or alternating current generator. 
         [0006]    These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art upon studying the following specification, claims, and appended drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a front perspective view of a base mold and a press mold used for making a two-pole coil configuration; 
           [0008]      FIG. 1A  is a bottom perspective view of the press mold of  FIG. 1 ; 
           [0009]      FIG. 1B  is a top elevational view of the base mold of  FIG. 1 ; 
           [0010]      FIG. 2  is a front perspective view of the base mold and press mold of  FIG. 1 , with the end turn forms removed; 
           [0011]      FIG. 3  is a front perspective view of the base mold and press mold of  FIG. 1  during formation of a conductive coil; 
           [0012]      FIG. 4  is a front perspective view of the press mold and base mold of  FIG. 1 , after the conductive coil has been formed; 
           [0013]      FIG. 5  is a front perspective view of a coil configuration for a two-pole motor or generator; 
           [0014]      FIG. 6A  is a front perspective view of another embodiment of a base mold and a press mold for a four-pole coil configuration following winding of a conductive material; 
           [0015]      FIG. 6B  is a side elevational view of the base mold and press mold of  FIG. 6A ; 
           [0016]      FIG. 6C  is a top elevational view of the base mold and press mold of  FIG. 6A ; 
           [0017]      FIG. 7  is a front perspective view of the base mold and press mold of  FIG. 6  during formation of a conductive coil; 
           [0018]      FIG. 8  is a front perspective view of a conductive coil configuration for a four-pole motor or generator; 
           [0019]      FIG. 9  is a front perspective view of another embodiment of a base mold and a press mold for a six-pole coil configuration following winding of a conductive material; 
           [0020]      FIG. 9A  is a top elevational view of the base mold of  FIG. 9 ; 
           [0021]      FIG. 10  is a front perspective view of the base mold and press mold of  FIG. 9  during formation of a conductive coil, with a portion of the press mold broken away; 
           [0022]      FIG. 11  is a front perspective view of a coil configuration for a six-pole motor or generator; 
           [0023]      FIG. 12  is a front perspective view of one embodiment of an insertion instrument of the present invention; 
           [0024]      FIG. 13  is a front perspective view of the insertion instrument of  FIG. 12  engaged with conductive coils prior to insertion into a stator core; 
           [0025]      FIG. 14  is a front perspective view of the insertion instrument of  FIG. 12  engaged with a conductive coil during insertion of the conductive coil into the stator core; 
           [0026]      FIG. 15  is a front perspective view of the insertion instrument of  FIG. 12  engaged with a conductive coil after complete insertion of the conductive coil into the stator core; 
           [0027]      FIG. 16  is a front perspective view of the conductive coil fully inserted into the stator core; 
           [0028]      FIG. 17  is a front perspective view of a molded insulator for a stator core; 
           [0029]      FIG. 18  is a front perspective view of a conductive coil inserted into a molded insulator; and 
           [0030]      FIG. 19  is a front perspective view of a conductive coil and molded insulator inserted into a stator core. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0031]    For purposes of description herein the terms “upper”, “lower”, “right”, “left”, “rear”, “front”, “vertical”, “horizontal” and derivatives thereof shall relate to the invention as oriented in  FIGS. 1-5 . However, it is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. 
         [0032]    Referring to  FIGS. 1-5 , the reference numeral  8  generally designates a molding system having a base mold  10  with first and second end turn forms  12 ,  14 . The first and second end turn forms  12 ,  14  are adapted to be inserted into first and second slots  16 ,  18  ( FIG. 2 ) that open upwardly on an engagement face  20  of the base mold  10 . The end turn forms  12 ,  14  are used to make a wound coil  22  for a brushless direct current motor, direct current generator, alternating current motor or alternating current generator. The wound coil  22  is made from a conductive material  25  wound about the first and second end turn forms  12 ,  14  to create one loop of conductive material. After winding is complete, the end turn forms  12 ,  14  may be removed from the base mold  10 . A press mold  24  is provided having an application face  26  that is complementary in shape to the engagement face  20  of the base mold  10 . The press mold  24  may have downwardly extending slots adapted to receive the end turn forms  12  and  14 . The one loop of conductive material  25  is formed between the application face  26  of the press mold  24  and the engagement face  20  of the base mold  10  to provide a formed coil  30  of conductive material. The formed coil  30  is removed from the engagement face  20  of the base mold  10 . The formed coil  30  is slid over an insertion instrument  32  ( FIG. 12 ). The insertion instrument  32  and the formed coil  30  are forced into a cylindrically-shaped stator core  34  ( FIG. 19 ). Optionally, the formed coil  30  may be bonded by a varnish or adhesive. The insertion instrument  32  is removed from the stator core  34 , and the stator core  34  is installed into one of a brushless direct current motor, direct current generator, alternating current motor or alternating current generator. 
         [0033]    Referring again to  FIGS. 1-4 , the engagement face  20  of the base mold  10  is generally convex, with the center of the base mold having a height greater than first and second sides  38 ,  40  of the base mold  10 . However, it is contemplated that other engagement face arrangements are possible. As shown in  FIG. 1B , the first and second end turn forms  12 ,  14  have a generally concave side  42  and a generally convex side  44  wherein the concave sides  42  of both the first and second end turn forms  12 ,  14  face inwardly toward the center of the base mold  10 . The application face  26  of the press mold  24  has a concave construction such that the center of the press mold has a depth less than the first and second sides  46 ,  48  of the press mold  24 . However, it is contemplated that other application face arrangements are possible. 
         [0034]    To prepare a two-pole coil for installation into the stator core for use in a brushless direct current motor, direct current generator, alternating current motor or alternating current generator, the first and second end turn forms  12 ,  14  are inserted into the first and second slots  16 ,  18 , respectively, of the base mold  10 . At least one strand of conductive material  25  is then wound about the ends and the convex side  42  of the first and second end turn forms  12 ,  14 . The distance D 1  between the end turn forms  12 ,  14  is equal to the height, or stack length, of the conductive coil  22  after the conductive coil  22  has been formed and installed into the stator core  34  plus room for clearance. The clearance refers to minimal spacing associated with the thickness of the conductive coil  22 . After a predetermined number of revolutions has been made around the end turn forms  12 ,  14  and a conductive coil  22  has been made, the conductive material is cut. The end turn forms  12 ,  14  may be removed from the first and second slots  16 ,  18 . Alternatively, the end turn forms  12 ,  14  may retract into first and second slots  16 ,  18 . The end turn forms  12 ,  14  may be spring biased to an extended position and pressed into the first and second slots  16 ,  18  by the application face  26  of the press mold  24 . The application face  26  of the press mold  24  is designed to descend upon and engage the engagement face  20  of the base mold  10  to shape the three dimensional formed conductive coil  30 . The press mold  24  is lifted and the formed conductive coil  30  is removed from the base mold  10 . Optionally, the formed coil  30  may be bonded by a varnish or adhesive. The formed conductive coil  30  for a two-pole motor or generator has two stack portions  50  and two end turn portions  52 . 
         [0035]    Referring now to  FIGS. 6A ,  6 B,  6 C,  7 , and  8 , to prepare a four-pole coil for installation into a stator core used in a brushless direct current motor, direct current generator, alternating current motor or alternating current generator, first and second end turn forms  60 ,  62  are inserted into first and second slots  64 ,  68 , ( FIG. 7 ) respectively, of first and second upwardly extending columns  70 ,  72 , respectively, on an engagement face  73  of a base mold  74 . Each upstanding column  70 ,  72  has a rectangular winding contour  75  adjacent to a slanted forming contour  76 . The first and second slots  64 ,  68  are disposed in the rectangular winding contour  75  of the first and second upwardly extending columns  70 ,  72 , respectively. At least one strand of conductive material  78  is then wound around the ends and a convex side  80  of each of the first and second end turn forms  60 ,  62 . After a predetermined number of revolutions has been made around the end turn forms  60 ,  62  and a conductive coil  82  having a rectangle-like shape has been made, the conductive material  78  is cut. The distance D 2  between the end turn forms  60 ,  62  is approximately equal to two times the stack length plus the pole pitch plus clearance. The end turn forms  60 ,  62  are then removed from the first and second slots  64 ,  68  in the rectangular winding contours  75  of the first and second upwardly extending columns  70 ,  72 . Alternatively, the end turn forms  60 ,  62  may retract into the first and second slots  64 ,  68 . The end turn forms  12 ,  14  may be spring biased to an extended position and pressed into the first and second slots  64 ,  68  by the application face  84  of the press mold  86 . An application face  84  of a press mold  86  engages the engagement face  73  of the base mold  74  to make a three dimensional formed conductive coil  90 . More specifically, two ridges  92  on the application face  84  contact the conductive coil  82  on two sides of the coil, thereby forcing the middle portion of the conductive coil  82  downwardly toward a bottom of the base mold  74 . As the conductive coil  82  is formed, the ends of the conductive coil  82  slide off the rectangular winding contour  75  of the first and second upwardly extending columns  70 ,  72  and onto the slanted forming contours  76 . The width W 1 , shown in  FIG. 6C , of the slanted forming contours  76  is approximately equal to the width W 2  of the end turn forms  60 ,  62  which is equal to the pole pitch present in the motor or generator being constructed. The height from the lowest side of the slanted forming contour to a bottom  94  of the base form is equal to the stack length of the formed conductive coil  90 . When the application face  84  contacts a bottom of the base form  74 , the formed conductive coil  90  is complete. The press mold  86  is lifted and the formed conductive coil  90  is removed from the base mold  74 . Optionally, the formed conductive coil  90  may be bonded by a varnish or adhesive. 
         [0036]    The conductive coil, shown in  FIG. 8 , for a four-pole motor or generator includes four stack portions  100  and four end turn portions  102 . As will be described in greater detail below, for each number of poles required for a particular motor or generator, the number of stack portions and end turn portions will be equal to the number of poles present. 
         [0037]    As shown in  FIGS. 9-11 , to prepare a six pole coil for installation into the stator for use in a brushless direct current motor, direct current generator, alternating current motor or alternating current generator, first, second, and third end turn forms  110 ,  112 ,  114  are inserted into first, second, and third slots  116 ,  118 ,  120 , respectively, present in first, second and third upwardly extending columns  122 ,  124 ,  126 , respectively, of a base mold  130 . Each upstanding column  122 ,  124 ,  126  has a rectangular winding contour  132  adjacent to a slanted forming contour  134 . The first, second, and third slots  116 ,  118 ,  120  are disposed in the rectangular winding contour  132  of the first, second and third upwardly extending columns  122 ,  124 ,  126 , respectively. At least one strand of conductive material  136  is then wound about the first, second, and third end turn forms  110 ,  112 ,  114  so that the conductive material  136  wraps around a convex side  140  of each end turn form  110 ,  112 ,  114 . The distance D 3  between the end turn forms  110 ,  112 ,  114  is approximately equal to two times the stack length plus the pole pitch plus clearance. After a predetermined number of revolutions have been made around the end turn forms  110 ,  112 ,  114  and a conductive coil  142  having a triangle-like shape has been made, the conductive material  136  is cut. The end turn forms  110 ,  112 ,  114  are then removed from the first, second, and third slots  116 ,  118 ,  120 , respectively, in the winding contour  132  of the first, second and third upwardly extending columns  122 ,  124 ,  126 , respectively. Alternatively, the end turn forms  110 ,  112 ,  114  may retract into the first, second and third slots  116 ,  118 ,  120 . The end turn forms  110 ,  112 ,  114  may be spring biased to an extended position and pressed into the first, second, and third slots  116 ,  118 ,  120  by the application face  144  of the press mold  146 . An application face  144  of a press mold  146  then engages an engagement face  148  of the base mold  130  to form a three dimensional formed conductive coil configuration  150  ( FIG. 11 ). More specifically, the application face  144  includes three ridges  152  adapted to contact the conductive material  136  on each of three sides of the conductive material  136 , and force the conductive material  136  downwardly toward the base of the upwardly extending columns  122 ,  124 ,  126 . As the formed conductive coil  150  is made, the ends of the formed conductive coil  150  slide off the rectangular winding contour  132  and onto the slanted forming contours  134 . The width W 1  of the slanted forming contour  134  is approximately equal to the width W 2  of the end turn forms  110 ,  112 ,  114  which is equal to the pole pitch that will be present in the motor or generator being constructed. The height from the lowest side of the slanted forming contours  134  to the engagement face  148  of the base form  130  may be equal to or more than the stack length. Optionally, the formed conductive coil  136  may be bonded by a varnish or adhesive. When the ridges  152  contact the engagement face  148  of the base form  130 , the conductive coil  136  is fully formed. The press mold  146  is lifted and the formed conductive coil  150  is removed from the base mold  130 . 
         [0038]    The formed conductive coil  150  for a six-pole motor or generator, as shown in  FIG. 11 , includes six stack portions  160  and six end turn portions  162 . The embodiments disclosed above are for illustration and it is contemplated that eight, ten, twelve, etc. pole motors or generators can be constructed in a similar manner as described above with respect to the two, four and six pole coil wind and form operations. For an eight, ten, twelve, etc. pole motor or generator, the conductive coil will have the same number of stack portions and end turn portions as the number of poles in the motor or generator. More coils may be appropriate if more phases are used in the motor or generator. 
         [0039]    Referring now to  FIGS. 12-16 , the insertion instrument  32  includes a conical front piece  172 , an elongate body  174 , a stop plate  176 , and a plunger  178 . Optionally, protrusions  175  may extend along the elongate body and provide some separation between multiple conductive coils arranged on the insertion instrument  32 . The blades may be angled or extend parallel with the longitudinal extent of the insertion instrument, as shown in  FIG. 12 . The tapered construction of the conical front piece  172  allows the insertion instrument  32  to be inserted between one or more conductive coils  180 , as shown in  FIG. 13 . The outside diameter of the insertion instrument  32  is designed to form and then size an inside diameter  179  ( FIG. 16 ) of the coils  180  to fit within an inside diameter of the stator core  34 . More specifically, the insertion instrument  32  has an outside diameter that is sized to shape an inside diameter  179  of a/many coil(s)  180  during insertion of the coil(s)  180  into the stator core  34 , regardless of the number of stack portions and end turn portions on the coil(s)  180 . The coils  180  are shown in  FIG. 13  having a shape similar to those in  FIG. 5 , but include rounded corners. In addition, the insertion instrument may be used to hold the conductive coils  180  while the coils  180  are being varnished or bonded. The insertion instrument  32  may include at least one hook  182  and may include several hooks  182  designed to contact and hold a portion of the conductive coil  180  prior to the conductive coil  180  being fully inserted into the stator core  34 . The hooks  182  are connected inside the elongate body  174  to the plunger  178 . Alternatively, there may be hooks  182  on the elongate body  174  near the stop plate  176 . When the plunger  178  is depressed, the hooks  182  retract into recesses  186  in the conical front piece  172 . In an alternative embodiment, the hooks  182  retract into the elongate body  174 . When the insertion instrument  32  has been inserted into the stator core  34  a predetermined distance, as shown in  FIG. 14 , the plunger  178  is depressed and the hooks  182  are retracted to allow the conductive coil  180  to slide back along the elongate body  174  of the insertion instrument  32  as shown in  FIG. 15 . Once the conductive coil  180  has been properly positioned inside the stator core  34 , the insertion instrument  32  is withdrawn from contact with the conductive coil  182 , leaving the conductive coil  182  in contact with an inside diameter of the stator core  34  ( FIG. 16 ). 
         [0040]    As shown in  FIGS. 17-19 , an insulator may be present inside the stator core  34 . A variety of different insulators may be used, including a sheet film insulator, powder insulator, molded insulator or any other insulator that is relatively nonconductive. If a sheet film insulator is used, the sheet film insulator is wrapped about the inside diameter of the stator core  34 . If a powder insulator is used, the stator core  34  may be electrically charged by a charging tool, and the powder is sprayed onto the stator core  34 . The powder is then wiped off of the outside diameter of the stator core  34  and allowed to remain on the inside of the stator core. The powder is then heated and cured to ensure that the powder provides a nonconductive solid coating that stays on the stator core  34 . Alternatively, the stator core  34  could be dipped in a fluidized bed of powder and cured. If a molded insulator  190 , as shown in  FIG. 17 , is used, the molded insulator  190  is typically shaped to be closely received in the stator core  34  and includes circumferential flanges  188  adapted to hold the molded insulator  190  in place inside the stator core  34 . The molded insulator  190  may include protrusions  192  that help hold the conductive coil  180  in place inside the molded insulator  190 . The molded insulator  190  is then inserted into the stator core  34 . After the molded insulator  190  is inserted into the stator core  34 , the conductive coil  180  is forced into the molded insulator  190  by the insertion instrument  32 , as described above. Alternatively, the conductive coil  180  may be inserted into the molded insulator  190  first by the insertion instrument  32 . Then the molded insulator  190  and conductive coil  180  together are inserted into the stator core  34  by the insertion instrument. The stator core  34  is then ready to be inserted into a motor or generator. 
         [0041]    The above description is considered that of the preferred embodiments only. Modifications of the invention will occur to those skilled in the art and to those who make or use the invention. Therefore, it is understood that the embodiments shown in the drawings and described above is merely for illustrative purposes and not intended to limit the scope of the invention, which is defined by the following claims as interpreted according to the principles of patent law, including the Doctrine of Equivalents.