Patent Publication Number: US-2023155457-A1

Title: Method of manufacturing stator and jig for manufacturing stator

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of Korean Patent Application No. 10-2021-0157549 filed in the Korean Intellectual Property Office on Nov. 16, 2021, and Korean Patent Application No. 10-2021-0157550 filed in the Korean Intellectual Property Office on Nov. 16, 2021, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a method of manufacturing a stator and a jig for manufacturing a stator, and more particularly, to a method of manufacturing a stator having a winding coil and a jig for manufacturing the stator. 
     BACKGROUND ART 
     A motor configured to convert electrical energy into kinetic energy includes a stator and a rotor. It is necessary to increase a space factor, which refers to a ratio of the volume occupied in a stator core by a coil, in order to improve the efficiency of the motor and reduce a loss of energy occurring on the coil wound around the stator. 
     However, in the related art, the increase in space factor of a slot causes problems that the coil cannot be properly inserted into the slot or damaged, the performance of the motor deteriorates due to the damage to the coil, or the safety is degraded. 
     In addition, in the case of a 3-phase motor in the related art, the coil supplied with a particular phase current (e.g., a U-phase current) among the currents with three phases is positioned further inward in the slot of the stator coil than the coil supplied with a current with another phase (e.g., a V-phase current or a W-phase current). For this reason, there is also a problem in that the physical properties of the coils are changed depending on the phases, which degrades the performance of the motor. 
     SUMMARY 
     The present disclosure has been made in an effort to minimize damage to a coil during a process of inserting the coil into a slot of a stator core. 
     The present disclosure has also been made in an effort to minimize a deviation in physical properties of a coil that occurs depending on phases of provided currents. 
     An exemplary embodiment of the present disclosure provides a method of manufacturing a stator, the method including: a preparation step of preparing a coil material and a stator core having a plurality of slots arranged in a circumferential direction C; a winding step of manufacturing a winding coil by winding the coil material; and an insertion step of positioning the winding coil in upper regions of at least some of the plurality of slots and then dropping the winding coil into the at least some of the plurality of slots. 
     In the insertion step, the winding coil may be dropped into the slot by gravity. 
     A through-hole G may be defined in a central region of the stator core, the plurality of slots may communicate with the through-hole G, and in the insertion step, the winding coil may be positioned in the through-hole G, and then the winding coil may be dropped into the at least some of the plurality of slots. 
     In the insertion step, the plurality of slots of the stator core may be disposed in a vertical direction, and the winding coil may be moved in a horizontal direction so as to be positioned in the through-hole G. 
     In the preparation step, the coil material may be prepared to include a first material, and a second material formed separately from the first material, and in the winding step, the winding coil may include a first bundle formed by winding the first material, and a second bundle provided by winding the second material. 
     In the winding step, the winding coil may include first and second bundles formed by winding the coil material, and the first and second bundles may be integrated by being connected to each other. 
     In the winding step, the first bundle having a first hole H 1  may be formed by winding one end of the first material in a first direction, and the second bundle having a second hole H 2  may be formed by winding one end of the second material in a second direction. 
     In the winding step, the first bundle having a first hole H 1  may be formed by winding one end of the coil material in a first direction, and then the second bundle having a second hole H 2  may be formed by winding one end of the coil material in a second direction. 
     In the winding step, the first and second bundles may be spaced apart from each other in a direction in which an imaginary plane extends, the imaginary plane being formed perpendicular to a direction in which the first and second holes H 1  and H 2  are formed through the first and second bundles. 
     In the winding step, the first and second bundles may be spaced apart from each other in a direction in which the first and second holes H 1  and H 2  are formed through the first and second bundles. 
     In the winding step, the first bundle having a first hole H 1  and the second bundle having a second hole H 2  may be formed by winding one end and the other end of the coil material in first and second directions, respectively, that are opposite to each other. 
     Another exemplary embodiment of the present disclosure provides a jig for manufacturing a stator, which is configured to transfer a winding coil and drop the winding coil into a stator core, the jig including: a first region; and a second region coupled to one side of the first region, in which the first region has a first recessed portion recessed upward, and the second region has a second recessed portion recessed upward. 
     The first and second regions may respectively include: upper portions disposed at upper sides of the first and second regions, respectively; and lower portions disposed at lower sides of the first and second regions and connected to the upper portions, respectively. The first recessed portion may be disposed in a lower surface of the lower portion of the first region, and the second recessed portion may be disposed in a lower surface of the lower portion of the second region. 
     The first recessed portion may extend to two opposite surfaces of the lower portion of the first region, and the second recessed portion may extend to two opposite surfaces of the lower portion of the second region. 
     The jig may further include: a third region coupled to one side of the second region; and a fourth region coupled to one side of the third region, the third region may have a third recessed portion recessed upward, and the fourth region may have a fourth recessed portion recessed upward. 
     The first to fourth regions may be configured to be assembled to one another. 
     The first to fourth regions may be integrated with each other. 
     A width of the upper portion may be larger than a width of the lower portion. 
     The first recessed portion may extend to the upper portion of the first region, and the second recessed portion may extend to the upper portion of the second region. 
     The jig may have a shape of fan ribs in which a direction in which the first region extends and a direction in which the second region extends define a predetermined angle therebetween, and a direction in which the third region extends and a direction in which the fourth region extends define a predetermined angle therebetween. 
     The direction in which the second region extends and the direction in which the third region extends may be parallel to each other. 
     According to the present disclosure, it is possible to minimize damage to the coil during the process of inserting the coil into the slot of the stator core. 
     In addition, according to the present disclosure, it is possible to minimize a deviation in physical properties of the coil that occurs depending on the phases of provided currents. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a view illustrating a state before a jig enters a through-hole of a stator core in a method of manufacturing a stator according to the present disclosure. 
         FIG.  2    is a view illustrating a state after the jig enters the through-hole of the stator core in the method of manufacturing a stator according to the present disclosure. 
         FIG.  3    is a perspective view illustrating a structure of a jig for manufacturing a stator according to the present disclosure. 
         FIGS.  4 A and  4 B  are views illustrating a first example of a method of making a winding coil by using a coil material in the method of manufacturing a stator according to the present disclosure. 
         FIGS.  5 A,  5 B, and  5 C  are views illustrating a second example of the method of making a winding coil by using a coil material in the method of manufacturing a stator according to the present disclosure. 
         FIGS.  6 A,  6 B, and  6 C  are views illustrating a third example of the method of making a winding coil by using a coil material in the method of manufacturing a stator according to the present disclosure. 
         FIG.  7    is a view illustrating a state before a winding coil is inserted into a jig for manufacturing a stator according to one example of the present disclosure. 
         FIG.  8    is a view illustrating a state after the winding coil is inserted into the jig for manufacturing a stator according to one example of the present disclosure. 
         FIG.  9    is a view illustrating a state before a winding coil is inserted into a jig for manufacturing a stator according to another example of the present disclosure. 
         FIG.  10    is a view illustrating a state after the winding coil is inserted into the jig for manufacturing a stator according to another example of the present disclosure. 
         FIG.  11    is a view illustrating a state in which a winding coil wound by a coil winding jig is inserted into a coil insertion jig in a method of manufacturing a stator according to another example of the present disclosure. 
         FIG.  12    is a side view illustrating a structure of the coil winding jig according to another example of the present disclosure. 
         FIG.  13    is a view illustrating a state before the coil insertion jig enters a through-hole of a stator core in the method of manufacturing a stator according to another example of the present disclosure. 
         FIG.  14    is a view illustrating a state after the coil insertion jig enters the through-hole of the stator core in the method of manufacturing a stator according to another example of the present disclosure. 
         FIG.  15    is a top plan view illustrating an example of the structure of the coil winding jig according to another example of the present disclosure. 
         FIG.  16    is a top plan view illustrating another example of the structure of the coil winding jig according to another example of the present disclosure. 
         FIG.  17    is an enlarged side view of a protruding portion of the coil winding jig according to another example of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, a method of manufacturing a stator and a jig for manufacturing a stator according to the present disclosure will be described with reference to the drawings. 
     Method of Manufacturing Stator 
       FIG.  1    is a view illustrating a state before a jig enters a through-hole of a stator core in a method of manufacturing a stator according to the present disclosure, and  FIG.  2    is a view illustrating a state after the jig enters the through-hole of the stator core in the method of manufacturing a stator according to the present disclosure.  FIG.  3    is a perspective view illustrating a structure of a jig for manufacturing a stator according to the present disclosure, and  FIGS.  4 A and  4 B  are views illustrating a first example of a method of making a winding coil by using a coil material in the method of manufacturing a stator according to the present disclosure. In addition,  FIGS.  5 A to  5 C  are views illustrating a second example of the method of making a winding coil by using a coil material in the method of manufacturing a stator according to the present disclosure, and  FIGS.  6 A to  6 C  are views illustrating a third example of the method of making a winding coil by using a coil material in the method of manufacturing a stator according to the present disclosure. 
     Referring to  FIGS.  1  to  6   , a method of manufacturing a stator according to the present disclosure may include a preparation step of preparing a coil material  200  and a stator core  100  having a plurality of slots S provided in a circumferential direction C, and a winding step of manufacturing a winding coil  300  by winding the coil material  200 . The plurality of slots S provided in the stator core  100  may be spaces into which the winding coil  300  manufactured from the coil material  200  is inserted. The plurality of slots S may be disposed at equal intervals. 
     In addition, the method of manufacturing a stator may further include an insertion step of positioning the winding coil  300  in upper regions of at least some of the plurality of slots S provided in the stator core  100  and then dropping the winding coil  300  into the slots S. 
     More specifically, in the insertion step, the winding coil  300  may be dropped in a direction perpendicular to the ground surface and dropped into the slots S by gravity. That is, according to the present disclosure, in the insertion step, the winding coil  300  may be inserted into the slots S without receiving separate external power. Therefore, according to the present disclosure, it is possible to prevent the winding coil  300  from being damaged during the process of inserting the winding coil  300  into the slots S of the stator core  100 . 
     More specifically, a through-hole G may be provided in a central region of the stator core  100 , and the plurality of slots S may communicate with the through-hole G. In this case, in the insertion step of the method of manufacturing a stator according to the present disclosure, the winding coil  300  may be positioned in the through-hole G, and then the winding coil  300  may be dropped into the slots S. That is, referring to  FIGS.  1  and  2   , a jig  400  into which the winding coil  300  (see  FIGS.  4  to  6   ) is inserted may be positioned outside the through-hole G before the insertion step as illustrated in  FIG.  1   , and then the jig  400  into which the winding coil  300  (see  FIGS.  4  to  6   ) is inserted may be positioned inside the through-hole G as illustrated in  FIG.  2    in the insertion step. 
     More particularly, in the insertion step, the jig  400  and the winding coil  300  may move in parallel with the ground surface. To this end, as illustrated in  FIGS.  1  and  2   , in the insertion step, the plurality of slots S of the stator core  100  may be disposed in a vertical direction, and the winding coil  300  may be moved in a horizontal direction and positioned in the through-hole G. 
     Meanwhile, referring to  FIGS.  4 A and  4 B , according to the first example of the present disclosure, in the preparation step, the coil material  200  may include a first material  210 , and a second material  220  provided separately from the first material  210 . In addition, in the winding step, the winding coil  300  may include a first bundle  310  made by winding the first material  210 , and a second bundle  320  made by winding the second material  220 . 
     More specifically, according to the first example of the present disclosure, in the winding step, the first bundle  310  having a first hole H 1  may be made by winding one end of the first material  210  in a first direction D 1  (e.g., clockwise), and the second bundle  320  having a second hole H 2  may be made by winding one end of the second material  220  in a second direction D 2  (e.g., counterclockwise).  FIG.  4    illustrates an example in which a lower end of the first material  210  and a lower end of the second material  220  are wound in the winding step. 
     In contrast, referring to  FIGS.  5 A to  5 C and  6 A to  6 C , according to the second and third examples of the present disclosure, in the winding step, the winding coil  300  may include the first and second bundles  310  and  320  made by winding the coil material  200 , and the first and second bundles  310  and  320  are integrated by being connected to each other. That is, according to the second and third examples of the present disclosure, the winding coil  300  including the first and second bundles  310  and  320  may be manufactured by using the single coil material  200 . 
     In this case, referring to  FIGS.  5 A to  5 C and  6 A to  6 C , according to the second and third examples of the present disclosure, in the winding step, the first bundle  310  having the first hole H 1  may be made by winding one end of the coil material  200  in the first direction D 1  (e.g., clockwise), and then the second bundle  320  having the second hole H 2  may be made by winding one end of the coil material  200  in the second direction D 2  (e.g., counterclockwise).  FIGS.  5 A to  5 C and  6 A to  6 C  illustrate an example in which in the winding step, the first bundle  310  having the first hole H 1  is made by winding a lower end of the coil material  200 , and the second bundle  320  having the second hole H 2  is made by winding an upper end of the coil material  200 . 
     More specifically, referring to  FIGS.  5 A to  5 C and  6 A to  6 C , according to the second and third examples of the present disclosure, in the winding step, i) the first bundle  310  having the first hole H 1  may be provided by winding one end of the coil material  200  in the first direction D 1  (e.g., clockwise), ii) one end of the coil material  200  may be extended in one direction, and then iii) the second bundle  320  having the second hole H 2  may be provided by winding one end of the coil material  200  in the second direction D 2  (e.g., counterclockwise). That is, according to the second and third examples of the present disclosure, the timing of forming the first bundle  310  and the timing of forming the second bundle  320  may be different from each other in a time series manner. 
     In this case, as illustrated in  FIGS.  5 A to  5 C , according to the second example of the present disclosure, in the winding step, the first and second bundles  310  and  320  may be spaced apart from each other in a direction in which an imaginary plane (i.e., a plane including the drawing based on  FIG.  5   ) extends, the imaginary plane being formed perpendicular to a direction in which the first and second holes H 1  and H 2  are formed through the first and second bundles  310  and  320  (i.e., a direction perpendicular to the drawing based on  FIG.  5   ). 
     In contrast, as illustrated in  FIGS.  6 A to  6 C , according to the third example of the present disclosure, in the winding step, the first and second bundles  310  and  320  may be spaced apart from each other in the direction in which the first and second holes H 1  and H 2  are formed through the first and second bundles  310  and  320  (i.e., in an upward/downward direction based on  FIG.  6 C ). To this end, according to the third example of the present disclosure, in the winding step, the first bundle  310  may be moved by a predetermined distance, in the direction in which the first hole H 1  is formed through the first bundle  310 , before the second bundle  320  is manufactured after the first bundle  310  is manufactured. 
     In contrast, according to the fourth example of the present disclosure, the timings of forming the first and second bundles  310  and  320  formed in one coil material  200  may overlap each other in a time series manner, unlike the second and third examples of the present disclosure. For example, according to the fourth example of the present disclosure, in the winding step, the first bundle  310  having the first hole H 1  and the second bundle  320  having the second hole H 2  may be provided by winding one end and the other end of the coil material  200  in opposite directions, i.e., the first direction (e.g., clockwise) and the second direction (e.g., counterclockwise). In this case, the timing of winding one end of the coil material  200  and the timing of winding the other end of the coil material  200  may overlap each other in a time series manner. 
     Meanwhile, the method of manufacturing a stator according to the present disclosure may further include, after the insertion step, a forming step of forming and processing ends of the winding coil and a connection step of connecting the winding coils. 
     Jig for Manufacturing Stator 
       FIG.  7    is a view illustrating a state before a winding coil is inserted into a jig for manufacturing a stator according to one example of the present disclosure, and  FIG.  8    is a view illustrating a state after the winding coil is inserted into the jig for manufacturing a stator according to one example of the present disclosure. In addition,  FIG.  9    is a view illustrating a state before a winding coil is inserted into a jig for manufacturing a stator according to another example of the present disclosure, and  FIG.  10    is a view illustrating a state after the winding coil is inserted into the jig for manufacturing a stator according to another example of the present disclosure. 
     Referring to  FIGS.  7  to  10   , the jig  400  for manufacturing a stator (hereinafter, referred to as a ‘jig’) according to the present disclosure may be a jig configured to transfer the winding coil  300  (see  FIGS.  1  to  6   ) and drop the winding coil into the stator core  100  (see  FIGS.  1  to  6   ). 
     More specifically, the jig  400  may include a first region  410 , a second region  420  coupled to one side of the first region  410 , a third region  430  coupled to one side of the second region  420 , and a fourth region  440  coupled to one side of the third region  430 . 
     In this case, according to the present disclosure, the first region  410  may have a first recessed portion  412  recessed upward, the second region  420  may have a second recessed portion  422  recessed upward, the third region  430  may have a third recessed portion  432  recessed upward, and the fourth region  440  may have a fourth recessed portion  442  recessed upward. 
     More specifically, the first to fourth regions  410 ,  420 ,  430 , and  440  may each include an upper portion  402  provided at an upper side of each of the first to fourth regions  410 ,  420 ,  430 , and  440 , and a lower portion  404  provided at a lower side of each of the first to fourth regions  410 ,  420 ,  430 , and  440  and connected to the upper portion  402 . In this case, the first recessed portion  412  may be formed in a lower surface of the lower portion  404  of the first region  410 , the second recessed portion  422  may be formed in a lower surface of the lower portion  404  of the second region  420 , the third recessed portion  432  may be formed in a lower surface of the lower portion  404  of the third region  430 , and the fourth recessed portion  442  may be formed in a lower surface of the lower portion  404  of the fourth region  440 . 
     In addition, the first recessed portion  412  may extend to two opposite surfaces of the lower portion  404  of the first region  410 , the second recessed portion  422  may extend to two opposite surfaces of the lower portion  404  of the second region  420 , the third recessed portion  432  may extend to two opposite surfaces of the lower portion  404  of the third region  430 , and the fourth recessed portion  442  may extend to two opposite surfaces of the lower portion  404  of the fourth region  440 . 
     Meanwhile, referring to  FIG.  3   , a width of the upper portion  402  of each of the first to fourth regions  410 ,  420 ,  430 , and  440  may be larger than a width of the lower portion  404  thereof. In this case, the first recessed portion  412  may extend to the upper portion  402  of the first region  410 , the second recessed portion  422  may extend to the upper portion  402  of the second region  420 , the third recessed portion  432  may extend to the upper portion  402  of the third region  430 , and the fourth recessed portion  442  may extend to the upper portion  402  of the fourth region  440 . In contrast, as illustrated in  FIGS.  7  to  8   , a width of the upper portion  402  of each of the first to fourth regions  410 ,  420 ,  430 , and  440  may be equal to a width of the lower portion  404  thereof. 
     In addition, the jig  400  according to the present disclosure may have a shape of fan ribs in which a direction in which the first region  410  extends and a direction in which the second region  420  extends define a predetermined angle therebetween, and a direction in which the third region  430  extends and a direction in which the fourth region  440  extends define a predetermined angle therebetween. In contrast, the direction in which the second region  420  extends and the direction in which the third region  430  extends may be parallel to each other. More particularly, the second region  420  and the third region  430  may extend downward. Therefore, the second recessed portion  422  and the third recessed portion  432  may extend upward in a direction perpendicular to the ground surface. The first recessed portion  412  and the fourth recessed portion  442  may extend upward while being inclined at a predetermined angle with respect to the ground surface. 
     Meanwhile, referring to  FIGS.  7  and  8   , the jig  400  according to the present disclosure may be assembled. More specifically, the first to fourth regions  410 ,  420 ,  430 , and  440  may be assembled to one another. However, referring to  FIGS.  9  and  10   , the first to fourth regions  410 ,  420 ,  430 , and  440  of the jig  400  according to the present disclosure may be integrated. 
     Hereinafter, a method of manufacturing a stator and a coil winding jig according to another example of the present disclosure will be described with reference to  FIGS.  11  to  17   . 
     Method of Manufacturing Stator 
       FIG.  11    is a view illustrating a state in which a winding coil wound by a coil winding jig is inserted into a coil insertion jig in a method of manufacturing a stator according to the present disclosure, and  FIG.  12    is a side view illustrating a structure of the coil winding jig according to the present disclosure.  FIG.  13    is a view illustrating a state before the coil insertion jig enters a through-hole of a stator core in the method of manufacturing a stator according to the present disclosure, and  FIG.  14    is a view illustrating a state after the coil insertion jig enters the through-hole of the stator core in the method of manufacturing a stator according to the present disclosure. 
     Referring to  FIGS.  11  to  14   , a method of manufacturing a stator according to the present disclosure may include a preparation step of preparing a coil material and a stator core  1100  having a plurality of slots S provided in a circumferential direction C 2 , and a winding step of manufacturing a winding coil by winding the coil material. The plurality of slots S provided in the stator core  1100  may be spaces into which the winding coil  1300  manufactured from the coil material is inserted. The plurality of slots S may be disposed at equal intervals. 
     In addition, the method of manufacturing a stator according to the present disclosure may further include an insertion step of inserting the winding coil  1300  manufactured in the winding step into a coil insertion jig  1600 , and a dropping step of moving the coil insertion jig  1600  so that the winding coil  1300  is positioned in upper regions of at least some of the plurality of slots S and then dropping the winding coil  1300  into the slots S. 
     More specifically, in the dropping step, the winding coil  1300  may be dropped in a direction perpendicular to the ground surface and dropped into the slots S by gravity. That is, according to the present disclosure, in the dropping step, the winding coil  1300  may be inserted into the slots S without receiving separate external power. Therefore, according to the present disclosure, it is possible to prevent the winding coil  1300  from being damaged during the process of inserting the winding coil  1300  into the slots S of the stator core  1100 . 
     More specifically, a through-hole G may be provided in a central region of the stator core  1100 , and the plurality of slots S may communicate with the through-hole G. In this case, in the dropping step of the method of manufacturing a stator according to the present disclosure, the coil insertion jig  1600  may be moved so that the winding coil  1300  is positioned in the through-hole G, and then the winding coil  1300  may be dropped into the slots S. That is, referring to  FIGS.  13  and  14   , the coil insertion jig  1600  into which the winding coil  1300  (see  FIG.  11   ) is inserted may be positioned outside the through-hole G before the dropping step, and then the coil insertion jig  1600  into which the winding coil  1300  (see  FIG.  11   ) is inserted may be positioned inside the through-hole G in the dropping step. 
     More particularly, in the dropping step, the coil insertion jig  1600  and the winding coil  1300  may move in parallel with the ground surface. To this end, as illustrated in  FIGS.  13  and  14   , in the dropping step, the plurality of slots S of the stator core  1100  may be disposed in a vertical direction, and the winding coil  1300  (see  FIG.  11   ) may be moved in a horizontal direction and positioned in the through-hole G. 
     Meanwhile, referring to  FIG.  11   , in the winding step of the method of manufacturing a stator according to the present disclosure, the winding coil  1300  may have first and second bundles  1310  and  1320  made by winding the coil material. In this case, the first and second bundles  1310  and  1320  may each include a plurality of winding regions  1302  spaced apart from one another in a direction (i.e., an upward/downward direction based on  FIG.  11   ) intersecting a direction (i.e., a leftward/rightward direction based on  FIG.  11   ) in which the winding coil  1300  extends. An interval D between the first bundle  1310  and the second bundle  1320  may be larger than an interval D 1  between the plurality of winding regions  1302  in the first bundle  1310  and an interval D 2  between the plurality of winding regions  1302  in the second bundle  1320 .  FIG.  11    illustrates that in the winding step, the winding coil  1300  has third and fourth bundles  1330  and  1340  in addition to the first and second bundles  1310  and  1320 . 
     In this case, an interval between the second bundle  1320  and the third bundle  1330  may be larger than the interval between the plurality of winding regions  1302  in the second bundle  1320  and an interval between a plurality of winding regions  1302  in the third bundle  1330 . In addition, an interval between the third bundle  1330  and the fourth bundle  1340  may be larger than the interval between the plurality of winding regions  1302  in the third bundle  1330  and an interval between a plurality of winding regions  1302  in the fourth bundle  1340 . 
     According to the present disclosure, the state in which the bundles  1310 ,  1320 ,  1330 , and  1340  of the winding coil  1300  manufactured by using the coil material are spaced apart from one another may be maintained. Therefore, it is possible to prevent the bundles  1310 ,  1320 ,  1330 , and  1340  from being entangled during the process of inserting the winding coil  1300  into the slots S of the stator core  1100 . Therefore, it is possible to minimize the occurrence of dead space in the slots S of the stator core  1100  that does not contribute to the performance. Therefore, it is possible to improve the space factor. 
     More specifically, according to the present disclosure, in the winding step, the coil material may be disposed on one surface of a coil winding jig  1500  having a shape extending in a longitudinal direction L of a shaft  1510 , and then the coil winding jig  1500  may be rotated about the shaft  1510  as a rotation axis, such that the winding coil  1300  may be manufactured. Further, the first and second bundles  1310  and  1320  may be spaced apart from one another with protruding portions  1520  (see  FIG.  12   ) interposed therebetween, the protruding portions  1520  being formed on the surface of the shaft  1510 . Similarly, the second bundle  1320  and the third bundle  1330  may also be spaced apart from one another with the protruding portions interposed therebetween, the protruding portions being formed on the surface of the shaft  1510 . The third bundle  1330  and the fourth bundle  1340  may also be spaced apart from one another with the protruding portions interposed therebetween, the protruding portions being formed on the surface of the shaft  1510 . 
     Meanwhile, according to the present disclosure, in the winding step, a lower region of the winding coil may be formed after an upper region of the winding coil is formed. In addition, the first bundle  1310  may be formed after the second bundle  1320  is formed. The second bundle  1320  may be formed after the third bundle  1330  is formed. The third bundle  1330  may be formed after the fourth bundle  1340  is formed. Therefore, according to the present disclosure, the first bundle  1310  may be disposed closer to the top side than is the second bundle  1320 . The second bundle  1320  may be disposed closer to the top side than is the third bundle  1330 . The third bundle  1330  may be disposed closer to the top side than is the fourth bundle  1340 . 
     Coil Winding Jig 
       FIG.  15    is a top plan view illustrating an example of the structure of the coil winding jig according to another example of the present disclosure, and  FIG.  16    is a top plan view illustrating another example of the structure of the coil winding jig according to another example of the present disclosure. 
     Referring to  FIGS.  11 ,  12 ,  15 , and  16   , the coil winding jig  1500  according to the present disclosure may include the shaft  1510  configured to define a body of the jig, a power supply unit (not illustrated) configured to provide power for rotating the shaft  1510 , and the protruding portions  1520  formed on the surface of the shaft  1510  and protruding outward. As described above, the protruding portions  1520  may be configured to allow the bundles of the winding coil  1300  to be spaced apart from one another. 
     Referring to  FIGS.  15  and  16   , the shaft  1510  may have a rod structure having a circular cross-section. However, the shaft  1510  may have a rod structure having an elliptical cross-section. 
     Meanwhile, as illustrated in  FIG.  15   , according to the example of the present disclosure, the protruding portion  1520  may have a shape of a closed curve extending in a circumferential direction C 1  of the shaft  1510 . However, as illustrated in  FIG.  16   , according to another example of the present disclosure, the protruding portion  1520  may have a shape of an open curve extending in the circumferential direction C 1  of the shaft  1510 .  FIG.  16    illustrates an example in which four protruding portions  1520  each having a shape of an open curve are disposed in the circumferential direction C 1  of the shaft  1510 , and the four protruding portions  1520  are disposed at equal intervals. 
     In addition, referring to  FIG.  12   , the protruding portion  1520  may be provided in plural, and the plurality of protruding portions  1520  may be spaced apart from one another in the longitudinal direction L of the shaft  1510 .  FIG.  12    illustrates an example in which five protruding portions  1520  are disposed at equal intervals in the longitudinal direction L of the shaft  1510 . 
       FIG.  17    is an enlarged side view of the protruding portion of the coil winding jig according to another example of the present disclosure. 
     Meanwhile, as illustrated in  FIGS.  12  and  17   , the protruding portion  1520  provided on the coil winding jig  1500  according to the present disclosure may include a lower surface  1522  directed downward, and an upper surface  1524  directed upward. In this case, the upper surface  1524  may include an inclined section  1524   a  inclined downward toward the outside in a radial direction R of the shaft  1510 . The lower surface  1522  may include a horizontal section  1522   a  extending horizontally in the radial direction R of the shaft  1510 . 
     According to the present disclosure, because the upper surface  1524  has the inclined section  1524   a,  the winding coil  1300  may easily slide along the inclined section  1524   a  when the winding coil  1300  is dropped from the coil winding jig  1500  so that the winding coil  1300  is inserted into the coil insertion jig  1600  in the insertion step. Therefore, the winding coil  1300  may be smoothly inserted into the coil insertion jig  1600 . In contrast, according to the present disclosure, because the lower surface  1522  has the horizontal section  1522   a,  it is possible to effectively prevent the lower region (e.g., second bundle) of the winding coil  1300  from being moved upward toward the upper region (e.g., first bundle) of the winding coil  1300 . 
     Referring to  FIG.  17   , the protruding portion  1520  may further include a lateral surface  1526  provided at an outer end based on the radial direction R and configured to connect the inclined section  1524   a  and the horizontal section  1522   a.  In this case, the lateral surface  1526  may include a curved surface section  1526   a  having a convex shape. 
     According to the present disclosure, because the lateral surface  1526  has the curved surface section  1526   a,  it is possible to prevent the winding coil  1300  from being damaged by the protruding portion  1520  during the process in which the winding coil  1300  passes over the protruding portion  1520  in the insertion step. 
     The present disclosure has been described with reference to the limited embodiments and the drawings, but the present disclosure is not limited thereto. The present disclosure may be carried out in various forms by those skilled in the art, to which the present disclosure pertains, within the technical spirit of the present disclosure and the scope equivalent to the appended claims.