Patent Publication Number: US-2020280229-A1

Title: Busbar device and method of manufacturing busbar device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to Japanese Patent Application No. 2019-036204, filed Feb. 28, 2019, the entire contents of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a busbar device to be used in a motor or a generator. 
     BACKGROUND 
     Currently, various types of bus rings for motors have been devised. For example, a bus ring according to Japanese Patent No. 6149673 is formed by laminating insulating sheets and busbars. The insulating sheets have holes and are aligned by inserting a positioning member into the holes. 
     Moreover, the bus ring described in Japanese Patent 6149673 needs to use the holes for the alignment of insulating sheets. However, this complicates the structure of each insulating sheet and also complicates a device on which the insulating sheets are mounted. As a result, a contact failure may occur during manufacturing the bus ring. 
     SUMMARY OF THE INVENTION 
     Accordingly, a busbar device of the present invention enables components to be aligned easily with a simple structure. 
     According to exemplary embodiments of the present invention, a busbar device includes at least one insulating sheet that is annularly formed by laminating an insulating layer and an adhesive layer and also includes an annular busbar. Moreover, the busbar is adhered to the adhesive layer. The at least one insulating sheet and the busbar are laminated in a direction parallel to a central axis of the busbar. 
     With this configuration, the insulating sheet and the busbar are adhered to each other. This configuration reduces the likelihood of the busbars being displaced in a radial direction and in a circumferential direction when the busbar and the insulating sheet are laminated and pressed together. 
     Additional features, elements, characteristics and advantages of the exemplary embodiments will become more apparent from the following detailed description of the present invention with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view illustrating an external appearance of a busbar device according to a first exemplary embodiment. 
         FIG. 2  is an exploded perspective view illustrating the busbar device according to the first exemplary embodiment. 
         FIG. 3  is a plan view illustrating the busbar device according to the first exemplary embodiment. 
         FIG. 4A  is a perspective view illustrating an external appearance of an insulating sheet according to the first exemplary embodiment. 
         FIG. 4B  is a cross section of the insulating sheet taken along line A-A in  FIG. 4A . 
         FIG. 5  is a perspective view illustrating an external appearance of the busbar device of the first exemplary embodiment being in a manufacturing process. 
         FIG. 6A  is a plan view illustrating the busbar device according to the first exemplary embodiment. 
         FIG. 6B  is a cross section of the busbar device taken along line B-B in  FIG. 6A . 
         FIG. 7  is a flowchart illustrating a manufacturing process of the busbar device according to the first exemplary embodiment. 
         FIG. 8  is a perspective view illustrating an external appearance of a busbar device according to a second exemplary embodiment. 
         FIG. 9A  is a perspective view illustrating an external appearance of a motor according to a third exemplary embodiment. 
         FIG. 9B  is a cross section of the motor taken along line C-C in  FIG. 9A . 
         FIG. 10A  is a perspective view illustrating an external appearance of a busbar device according to a fourth exemplary embodiment. 
         FIG. 10B  is a cross section of the busbar device taken along line D-D in  FIG. 10A . 
         FIG. 11A  is a perspective view illustrating an external appearance of a busbar device according to a fifth exemplary embodiment. 
         FIG. 11B  is a cross section of the busbar device taken along line B-B in  FIG. 11A . 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     First Exemplary Embodiment 
     A busbar device according to a first exemplary embodiment will be described with reference to the drawings.  FIG. 1  is a perspective view illustrating an external appearance of a busbar device  10  according to the first embodiment.  FIG. 2  is an exploded perspective view illustrating the busbar device  10  according to the first embodiment.  FIG. 3  is a plan view illustrating the busbar device  10  according to the first embodiment.  FIG. 4A  is a perspective view illustrating an external appearance of an insulating sheet  101  according to the first embodiment, and  FIG. 4B  is a cross section of the insulating sheet  101  taken along line A-A in  FIG. 4A .  FIG. 5  is a perspective view illustrating an external appearance of the busbar device  10  according to the first embodiment.  FIG. 6A  is a plan view illustrating the busbar device  10  according to the first embodiment, and  FIG. 6B  is a cross section of the busbar device  10  taken along line B-B in  FIG. 6A .  FIG. 7  is a flowchart illustrating a manufacturing process of the busbar device  10  according to the first embodiment. In figures provided for describing the following exemplary embodiments, it should be appreciated that relationships between vertical and lateral dimensions may be exaggerated from time to time and may not reflect actual dimensions. Some reference symbols may be omitted to improve visual recognition. 
     As illustrated in  FIGS. 1 and 2 , the busbar device  10  includes an insulating sheet unit  100  and a busbar unit  200 . The insulating sheet unit  100  has a predetermined thickness and includes annularly shaped insulating sheets  101 ,  102 ,  103 , and  104 . The busbar unit  200  has a predetermined thickness and includes annularly shaped busbars  201 ,  202 , and  203 . In general, the thickness of each insulating sheet  101 ,  102 ,  103 , or  104  is smaller than the thickness of each busbar  201 ,  202 , or  203 . 
     Structure of Insulating Sheet 
     A structure of the insulating sheet unit  100  will be described with reference to  FIG. 2 . As described, the insulating sheet unit  100  includes the insulating sheets  101 ,  102 ,  103 , and  104 . 
     The insulating sheet  101  has an annular shape and has an inner circumference D 11  and an outer circumference D 21 . The insulating sheet  101  has multiple tabs  151  that protrude outward from the outer circumference D 21 . 
     The insulating sheet  102  has an annular shape and has an inner circumference D 12  and an outer circumference D 22 . The insulating sheet  103  has an annular shape and has an inner circumference D 13  and an outer circumference D 23 . 
     The insulating sheet  104  has an annular shape and has an inner circumference D 14  and an outer circumference D 24 . The insulating sheet  104  has multiple tabs  152  that protrude outward from the outer circumference D 24 . 
     As further shown, the shapes of the inner circumferences D 11 , D 12 , D 13 , and D 14  are preferably the same. The shapes of the outer circumferences D 21 , D 22 , D 23 , and D 24  are also preferably the same. This can simplify the manufacturing process of the insulating sheets  101 ,  102 ,  103 , and  104 . 
     Structure of Busbar 
     Next, a structure of the busbar unit  200  will be described with reference to  FIG. 2 . As described, the busbar unit  200  includes the busbars  201 ,  202 , and  203 . The busbars  201 ,  202 , and  203  are made, for example, of copper (Cu) in an exemplary aspect. 
     The busbar  201  has an inner circumference D 31  and an outer circumference D 41 . The busbar  201  includes multiple connection terminals  251  and an output terminal  261  that protrude outward from the outer circumference D 41 . 
     Each connection terminal  251  includes a link portion  2511  and a bent portion  2512 . The output terminal  261  includes a link portion  2611  and a bent portion  2612 . Each of the link portions  2511  and the link portion  2611  is formed so as to be flush with a tabular region of the annular busbar  201  defined between the inner circumference D 31  and the outer circumference D 41  and is formed so as to have one end connected to the outer circumference D 41 . Each bent portion  2512  is connected to the other end of each link portion  2511  and is formed into a U-shape that extends in the height direction. It is noted that the height direction is a direction that orthogonally intersects the tabular region of the busbar  201 , which can be considered a direction parallel to a central axis of the busbar in the present disclosure. 
     The busbar  202  has an inner circumference D 32  and an outer circumference D 42 . The busbar  202  includes multiple connection terminals  252  and an output terminal  262  that protrude outward from the outer circumference D 42 . 
     Each connection terminal  252  includes a link portion  2521  and a bent portion  2522 . The output terminal  262  includes a link portion  2621  and a bent portion  2622 . Each of the link portions  2521  and the link portion  2621  is formed so as to be flush with a tabular region of the annular busbar  202  defined between the inner circumference D 32  and the outer circumference D 42  and is formed so as to have one end connected to the outer circumference D 42 . Each bent portion  2522  is connected to the other end of each link portion  2521  and is formed into a U-shape that extends in the height direction. 
     The busbar  203  has an inner circumference D 33  and an outer circumference D 43 . The busbar  203  includes multiple connection terminals  253  and an output terminal  263  that protrude outward from the outer circumference D 43 . 
     Each connection terminal  253  includes a link portion  2531  and a bent portion  2532 . The output terminal  263  includes a link portion  2631  and a bent portion  2632 . Each of the link portion  2531  and the link portion  2631  is formed so as to be flush with a tabular region of the annular busbar  203  defined between the inner circumference D 33  and the outer circumference D 43  and is formed so as to have one end connected to the outer circumference D 43 . Each bent portion  2532  is connected to the other end of each link portion  2531  and is formed into a U-shape that extends in the height direction. 
     According to an exemplary aspect, the bent portions  2512  are provided at at least three positions along the outer circumference D 41  of the busbar  201  so as to surround the central axis of the busbar  201 . Moreover, the bent portions  2522  are provided at at least three positions along the outer circumference D 42  of the busbar  202  so as to surround the central axis of the busbar  202 . Likewise, the bent portions  2532  are provided at at least three positions along the outer circumference D 43  of the busbar  203  so as to surround the central axis of the busbar  203 . 
     The connection terminals  251 , the connection terminals  252 , and the connection terminals  253  have similar shapes but different lengths. Moreover, the output terminal  261 , the output terminal  262 , and the output terminal  263  have similar shapes. It is noted that the output terminals  261 ,  262 , and  263  are input/output terminals for electric power. 
     The connection terminals  251 ,  252 , and  253  and the output terminals  261 ,  262 , and  263  are disposed systematically along the outer circumference D 43 . Here, the distance from the center of the busbar  201  to the inside surface (i.e., the surface near the center) of bent portion  2512  of each connection terminal  251  is the same as the distance from the center of the busbar  202  to the inside surface of the bent portion  2522  of each connection terminal  252  and the distance from the center of the busbar  203  to the inside surface of the bent portion  2532  of each connection terminal  253 . Structural details will be described later. 
     Positional Relationship of Busbar Device and Insulating Sheet 
     Positional relationships of the insulating sheets  101 ,  102 ,  103 , and  104  and the busbars  201 ,  202 , and  203 , which form the busbar device  10 , will be described with reference to  FIG. 2 . 
     The busbar device  10  is formed by laminating, vertically from bottom to top, the insulating sheet  104 , the busbar  203 , the insulating sheet  103 , the busbar  202 , the insulating sheet  102 , the busbar  201 , and the insulating sheet  101 . 
     The insulating sheet  104  and the busbar  203  are adhered to each other at opposing surfaces. Similarly, the busbar  203  and the insulating sheet  103  are adhered to each other at opposing surfaces. 
     For purposes of this disclosure, the insulating sheet  104  can be considered a first insulating sheet, and the insulating sheet  103  can be considered a second insulating sheet. Moreover, the surface of the busbar  203  opposing the insulating sheet  104  can be considered a first principal surface, and the surface of the busbar  203  opposing the insulating sheet  103  can be considered a second principal surface. 
     The insulating sheet  103  and the busbar  202  are adhered to each other at opposing surfaces. The busbar  202  and the insulating sheet  102  are adhered to each other at opposing surfaces. 
     According to the present disclosure, the insulating sheet  103  can be considered a first insulating sheet, and the insulating sheet  102  can be considered a second insulating sheet. Moreover, the surface of the busbar  202  opposing the insulating sheet  103  can be considered a first principal surface, and the surface of the busbar  202  opposing the insulating sheet  102  can be considered a second principal surface. 
     The insulating sheet  102  and the busbar  201  are adhered to each other at opposing surfaces. The busbar  201  and the insulating sheet  101  are adhered to each other at opposing surfaces. 
     According to the present disclosure, the insulating sheet  102  can be considered a first insulating sheet, and the insulating sheet  101  can be considered a second insulating sheet. Moreover, the surface of the busbar  201  opposing the insulating sheet  102  can be considered a first principal surface, and the surface of the busbar  201  opposing the insulating sheet  101  can be considered a second principal surface. 
     Thus, the insulating sheet unit  100  and the busbar unit  200  are adhered to each other. 
     The tabs  151  of the insulating sheet  101  and the tabs  152  of the insulating sheet  104  are formed such that the tabs  151  overlap respective tabs  152  as viewed vertically from above the busbar device  10 . Accordingly, the tabs  151  come into contact with the tabs  152  when the insulating sheet  101  and the insulating sheet  104  are laminated. 
     Here, it is preferable that the entire surfaces of the busbars  201 ,  202 , and  203  be adhered to corresponding insulating sheets  101 ,  102 ,  103 , and  104  according to an exemplary aspect. This can reduce the likelihood of the busbars deviating in a radial direction and in a circumferential direction when the busbar device  10  is formed by laminating and pressing the busbars. 
     The connection terminals  251 ,  252 , and  253  and the output terminals  261 ,  262 , and  263  are formed so as not to overlap each other as viewed vertically from above the busbar device  10 . Similarly, the tabs  151  and  152  are formed so as not to overlap the connection terminals  251 ,  252 , and  253  and the output terminals  261 ,  262 , and  263  as viewed vertically from above the busbar device  10 . In other words, each pair of the tabs  151  and  152  is formed between adjacent ones of the connection terminals  251 ,  252 , and  253  and the output terminals  261 ,  262 , and  263 . 
     Each tab  151  is adhered to the corresponding tab  152  at opposing surfaces thereof. 
       FIG. 3  is a plan view illustrating the busbar device  10 . In  FIG. 3 , the insulating sheet  101  and the busbar  201  are illustrated by way of example. However, the same configuration applies to the insulating sheets  102 ,  103 , and  104  and to the busbars  202  and  203 . It is noted that the tabs  151  of the insulating sheet  101  are omitted to facilitate clear understanding. 
     For purposes of this disclosure, when the busbar device  10  is viewed in a plan view, a center CP of the busbar device  10  corresponds to the center of the insulating sheet  101  and the center of the busbar  201 . 
     Moreover, d 1  denotes the distance from the center CP to the inner circumference D 11  of the insulating sheet  101 , and d 2  denotes the distance from the center CP to the outer circumference D 21  of the insulating sheet  101 . Similarly, d 3  denotes the distance from the center CP to the inner circumference D 31  of the busbar  201 , and d 4  denotes the distance from the center CP to the outer circumference D 41  of the busbar  201 . The width of the insulating sheet  101  (i.e., d 2 −d 1 ) is greater than the width of the busbar  201  (i.e., d 4 −d 3 ). Moreover, in an exemplary embodiment, the insulating sheet  101  and the busbar  201  are formed so as to satisfy the following formula: distance d 1 &lt;distance d 3 &lt;distance d 4 &lt;distance d 2 . 
     With this configuration, the insulating sheets  101 ,  102 ,  103 , and  104  cover the busbars  201 ,  202 , and  203  over both of the annular principal surfaces and the outer and inner circumferential surfaces thereof. In other words, the busbar unit  200  is shaped so as to be covered by the insulating sheet unit  100 . As a result, the busbars  201 ,  202 , and  203  are insulated individually, which improves isolation of the busbars  201 ,  202 , and  203  from each other. 
     Moreover, with this configuration, the insulating sheets  101 ,  102 ,  103  and  104  can be adhered appropriately to the busbars  201 ,  202 , and  203 , for example, during handling of components when the busbar device  10  is formed even if each insulating sheet does not have a complicated registration arrangement. Accordingly, misregistration of the busbar unit  200  and the insulating sheet unit  100  relative to each other can be suppressed. This can simplify the structure of the insulating sheet, which improves the yield rate of the product. 
     In addition, the tabs  151  and the corresponding tabs  152  are adhered to each other at the opposing surfaces thereof, which improves the adhesion strength between the insulating sheet  101  and the insulating sheet  104 . The adhered tabs  151  and  152  are positioned outside the outer circumferences of the busbars. Accordingly, the likelihood of the busbars deviating outward in a radial direction can be reliably suppressed due to the adhesion strength of the tabs  151  and  152 . It is noted that tabs may be provided for the insulating sheet  102  and the insulating sheet  103  to improve the adhesion strength further. 
     It is also noted that in the case of the busbar device  10  being used in an environment where foreign matter (such as water, oil, or metal powder) is not likely to enter the busbar device  10 , the tabs  151  and  152  may be omitted. 
     The structure of the insulating sheet unit  100  will be described more specifically with reference to  FIGS. 4A and 4B . Although  FIG. 4B  illustrates the insulating sheet  101  as an example, the same configuration applies to the insulating sheets  102 ,  103 , and  104 . 
     As illustrated in  FIG. 4B , the insulating sheet  101  is formed by laminating an adhesive layer  111 , an insulating layer  112 , and another adhesive layer  111 . In other words, the adhesive layers  111  are disposed on respective principal surfaces of the insulating layer  112 . 
     Each adhesive layer  111  is made, for example, of an acrylic adhesive, a polysilan adhesive, or a polyurethane adhesive. It is noted that the adhesive layer  111  may be made of any adhesive material but is preferably made of an acrylic adhesive. The adhesive layer  111  made of the acrylic adhesive has thermal resistance and provides sufficient adhesiveness even if the layer is thin. 
     It is preferable that the adhesive layer  111  and the insulating layer  112  have the same thickness. However, the adhesive layer  111  and the insulating layer  112  may have different thicknesses insofar as the adhesive layer  111  and the insulating layer  112  can be adhered to each other. The adhesive layer  111  may be formed of a cohesive material. 
     Furthermore, the insulating layer  112  is made of a thermoplastic engineering plastic material, such as polyphenylene sulfide (PPS), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or aromatic polyamide. 
     In an exemplary aspect, the adhesive layer  111  may cover only one principal surface of the insulating layer  112 . Moreover, the adhesive layer  111  may be omitted especially for the principal surface of the insulating sheet  101  that does not come into contact with the busbar  201 . Similarly, the adhesive layer  111  may be omitted especially for the principal surface of the insulating sheet  104  that does not come into contact with the busbar  203 . 
     Next, a structure of the busbar device  10  will be described with reference to  FIGS. 5, 6A, and 6B . The busbar device  10  is manufactured using a first jig  310 . In these figures, the tabs  151  of the insulating sheet  101  and the tabs  152  of the insulating sheet  104  are not illustrated to improve visual recognition. 
     As illustrated in  FIG. 5 , the first jig  310  includes a first portion  311  and a second portion  312 . Although the positional relationship is described by focusing on the insulating sheet  104  and the busbar  203 , the same relationship is also applied to the insulating sheets  101 ,  102 , and  103  and the busbars  201  and  202 . The insulating sheet  104  is marked by hatching to clarify the positional relationship between the insulating sheet  104  and the busbar  203 . 
     The first jig  310  is formed by layering the columnar first portion  311  on top of the columnar second portion  312 . The first jig  310  is preferably formed such that the center of the first portion  311  corresponds to the center of the second portion  312  when the first jig  310  is viewed in plan. 
     Here, R 1  denotes the outer circumference of the first portion  311 , and R 2  denotes the outer circumference of the second portion  312 . When the first jig  310  is viewed in plan, the first portion  311  is smaller than the second portion  312 . In other words, the outer circumference R 1  of the first portion  311  is smaller than the outer circumference R 2  of the second portion  312 . The first jig  310  includes multiple protrusions  315  that protrude outward from the outer circumference R 2  of the second portion  312 . 
     The insulating sheet  104  is placed so as to surround the outer circumference R 1  of the first portion  311 . More specifically, the inner circumference D 14  of the insulating sheet  104  is placed along the outer circumference R 1  of the first portion  311 . 
     In other words, the outer circumference R 1  of the first portion  311  has substantially the same shape and size as the shape and size of the inner circumference D 14  of the insulating sheet  104 . This facilitates alignment of the insulating sheet  104  when the insulating sheet  104  is placed on the first jig  310  (around the first portion  311 ). 
     The busbar  203  is also placed on the first jig  310  such that the bent portions  2532  of the busbar  203  are brought into contact with the outer circumference R 2  of the second portion  312 . In other words, the distance from the center of the second portion  312  to the outer circumference R 2  (i.e., the radius of the second portion  312 ) is substantially the same as the distance from the center of the busbar  203  to each bent portion  2532 . This facilitates alignment of the busbar  203  when the busbar  203  is placed on the first jig  310  (around the second portion  312 ). 
     Structural details of the busbar device  10  will be described with reference to  FIGS. 6A and 6B . In  FIG. 6A , the insulating sheet  101  is marked by hatching to clarify the positional relationship between the insulating sheet  101  and the first jig  310 . 
     As illustrated in  FIGS. 6A and 6B , the insulating sheets  101 ,  102 ,  103 , and  104  are arranged so as to surround the outer circumference R 1  of first portion  311  of the first jig  310 . More specifically, the inner circumference D 11  of the insulating sheet  101 , the inner circumference D 12  of the insulating sheet  102 , the inner circumference D 13  of the insulating sheet  103 , and the inner circumference D 14  of the insulating sheet  104  are placed along the outer circumference R 1  of first portion  311  of the first jig  310  and aligned in the height direction. 
     The busbars  201 ,  202 , and  203  are arranged on the first jig  310  such that the connection terminals  251 ,  252 , and  253  are placed along the outer circumference R 2  of second portion  312  of the first jig  310 . 
     In addition, the output terminals  261 ,  262 , and  263  are aligned by using protrusions  315 . In other words, the protrusions  315  are used for positioning the busbars  201 ,  202 , and  203  in a circumferential direction. 
     As further shown in  FIG. 6B , the inner circumference D 11  of the insulating sheet  101 , the inner circumference D 12  of the insulating sheet  102 , the inner circumference D 13  of the insulating sheet  103 , and the inner circumference D 14  of the insulating sheet  104  come into contact with the outer circumference R 1  of the first portion  311 . Moreover, the bent portions  2512  of the connection terminals  251 , the bent portions  2522  of the connection terminals  252 , and the bent portions  2532  of the connection terminals  253  come into contact with the surface of outer circumference R 2  of the second portion  312 . 
     Thus, when the insulating sheets  101 ,  102 ,  103 , and  104  and the busbars  201 ,  202 , and  203  are placed on the first jig  310 , these components can be aligned easily. The output terminals  261 ,  262 , and  263  can be disposed so as not to interfere with each other due to the protrusions  315  determining the positions of the output terminals  261 ,  262 , and  263 . This configuration suppresses deviation of the insulating sheet unit  100  and the busbar unit  200  relative to each other. Accordingly, the configuration simplifies the structure of the insulating sheet. 
     In the case of the busbars  201 ,  202 , and  203  being heated while power is supplied, the busbars  201 ,  202 , and  203  may expand toward the outside of the outer circumferences of the busbars. In this case, the outer circumferences of respective busbars  201 ,  202 , and  203  may break the mutual adhesion of the insulating sheets  101 ,  102 ,  103 , and  104 , which may degrade insulation performance. However, the outer circumferences of the insulating sheets  101 ,  102 ,  103 , and  104  are positioned at or near the outer circumference R 2  of the second portion  312 , while the busbars  201 ,  202 , and  203  are disposed so as to be closer to the outer circumference R 1  of the first portion  311  than to the outer circumference R 2  of the second portion  312 . Accordingly, the busbars  201 ,  202 , and  203  are disposed closer to the inner circumferences of the insulating sheets  101 ,  102 ,  103 , and  104 . This configuration suppresses breakage of the insulating sheet unit  100  caused by expansion of the busbars  201 ,  202 , and  203 . 
     Next, a process of manufacturing the busbar device  10  using the first jig  310  will be described with reference to  FIG. 7 . 
     In step S 101 , the insulating sheet  104  is disposed such that the inner circumference D 14  of the insulating sheet  104  is placed along the outer circumference R 1  of first portion  311  of the first jig  310 . 
     In step S 102 , the busbar  203  is placed such that the bent portions  2532  of the busbar  203  are brought into contact with the outer circumference R 2  of second portion  312  of the first jig  310 . 
     In step S 103 , the insulating sheet  104  and the busbar  203  are adhered to each other. 
     Steps S 101 , S 102 , and S 103  are repeated by the number of times corresponding to the number of layers of the busbar and insulating sheet. In the present embodiment, the insulating sheets  101 ,  102 , and  103  and the busbars  201  and  202  are subsequently laminated and adhered. 
     In step S 104 , the tabs  151  of the insulating sheet  101  are adhered to the corresponding tabs  152  of the insulating sheet  104 . 
     By using the above manufacturing process, the members of the busbar device  10  can be aligned easily when placed on the first jig  310 , and the positional relationships of the insulating sheets  101 ,  102 ,  103 , and  104  and the busbars  201 ,  202 , and  203  can be fixed reliably. 
     According to an exemplary aspect, it is preferable that the shapes of at least the insulating sheet  101  and the insulating sheet  104  excluding respective tabs  151  and  152  be substantially the same. It is also preferable that the width of at least the insulating sheets  102  and  103  be greater than the width of the busbars  201 ,  202 , and  203 . 
     The insulating sheets  101 ,  102 ,  103 , and  104  described above are examples having annular shapes. However, each insulating sheet may have a polygonal shape or may be formed into an annular shape by combining multiple sheet segments together circumferentially. 
     Similarly, the busbars  201 ,  202 , and  203  described above are examples having annular shapes. However, each busbar may have a polygonal shape or may be formed into an annular shape by combining multiple busbar segments together circumferentially. 
     In addition, the first jig  310  described above is an example having a columnar first portion  311  and a columnar second portion  312 . However, the first jig  310  can function similarly in the case in which the first portion  311  and the second portion  312  have polygonal shapes each of which has three corners or more. 
     Second Exemplary Embodiment 
     A busbar device according to a second embodiment of the present invention will be described with reference to the drawings.  FIG. 8  is a perspective view illustrating an external appearance of a busbar device  10 A according to the second embodiment. 
     As illustrated in  FIG. 8 , the shapes of insulating sheets  101 A,  102 A,  103 A, and  104 A, the shapes of connection terminals  251 A,  252 A, and  253 A, and the shapes of output terminal  261 A,  262 A,  263 A of the busbar device  10 A according to the second embodiment are different from those of the busbar device  10  according to the first embodiment. Additional configurations of the busbar device  10 A are similar to those of the busbar device  10 , and the description of similar configurations will not be repeated. 
     The busbar  201 A includes connection terminals  251 A and an output terminal  261 A. The busbar  202 A includes connection terminals  252 A and an output terminal  262 A. The busbar  203 A includes connection terminals  253 A and an output terminal  263 A. 
     The output terminal  261 A includes a link portion  2611 A but does not include a bent portion. The output terminal  262 A includes a link portion  2621 A but does not include a bent portion. The output terminal  263 A includes a link portion  2631 A but does not include a bent portion. 
     As further shown, the insulating sheets  101 A and  102 A are shaped so as to cover the output terminal  261 A entirely. More specifically, the insulating sheet  101 A includes a rectangularly shaped strip portion T 11  at a position corresponding to the output terminal  261 A. The strip portion T 11  protrudes outward from the outer circumference D 21  of the insulating sheet  101 A. In addition, the insulating sheet  102 A includes a rectangularly shaped strip portion T 12  at a position corresponding to the output terminal  261 A. The strip portion T 12  protrudes outward from the outer circumference D 22  of the insulating sheet  102 A. 
     The strip portion T 11  is shaped so as to have a size that is larger than the output terminal  261 A when measured in a direction parallel to the surface of the output terminal  261 A with which the strip portion T 11  comes into contact, and the strip portion T 12  is shaped so as to have a size larger than the output terminal  261 A when measured in a direction parallel to the surface of the output terminal  261 A with which the strip portion T 12  comes into contact. The strip portion T 11  and the strip portion T 12  having such shapes come into contact with the output terminal  261 A and thereby cover the output terminal  261 A entirely. 
     Similarly, the insulating sheets  102 A and  103 A are shaped so as to cover the output terminal  262 A entirely. More specifically, the insulating sheet  102 A includes a rectangularly shaped strip portion T 13  at a position corresponding to the output terminal  262 A. The strip portion T 13  protrudes outward from the outer circumference D 22  of the insulating sheet  102 A. In addition, the insulating sheet  103 A includes a rectangularly shaped strip portion T 14  at a position corresponding to the output terminal  262 A. The strip portion T 14  protrudes outward from the outer circumference D 23  of the insulating sheet  103 A. 
     The strip portion T 13  is also shaped so as to have a size larger than the output terminal  262 A when measured in a direction parallel to the surface of the output terminal  262 A with which the strip portion T 13  comes into contact, and the strip portion T 14  is shaped so as to have a size larger than the output terminal  262 A when measured in a direction parallel to the surface of the output terminal  262 A with which the strip portion T 14  comes into contact. The strip portion T 13  and the strip portion T 14  having such shapes come into contact with the output terminal  262 A and thereby cover the output terminal  262 A entirely. 
     Furthermore, the insulating sheets  103 A and  104 A are shaped so as to cover the output terminal  263 A entirely. More specifically, the insulating sheet  103 A includes a rectangularly shaped strip portion T 15  at a position corresponding to the output terminal  263 A. The strip portion T 15  protrudes outward from the outer circumference D 23  of the insulating sheet  103 A. In addition, the insulating sheet  104 A includes a rectangularly shaped strip portion T 16  at a position corresponding to the output terminal  263 A. The strip portion T 16  protrudes outward from the outer circumference D 24  of the insulating sheet  104 A. 
     As further shown, the strip portion T 15  is shaped so as to have a size larger than the output terminal  263 A when measured in a direction parallel to the surface of the output terminal  263 A with which the strip portion T 15  comes into contact, and the strip portion T 16  is shaped so as to have a size larger than the output terminal  263 A when measured in a direction parallel to the surface of the output terminal  263 A with which the strip portion T 16  comes into contact. The strip portion T 15  and the strip portion T 16  having such shapes come into contact with the output terminal  263 A and thereby cover the output terminal  263 A entirely. 
     Accordingly, the output terminals  261 A,  262 A, and  263 A are covered by the corresponding insulating sheets  101 A,  102 A,  103 A, and  104 A. 
     When insulating sheets cover respective output terminals  261 A,  262 A, and  263 A entirely, the insulating sheets cover both tabular surfaces of each output terminal and side surfaces connected to the tabular surfaces so as not to impair the connection function of the output terminals  261 A,  262 A, and  263 A. 
     With this configuration, not only the busbars  201 A,  202 A, and  203 A, but also the output terminals  261 A,  262 A, and  263 A are insulated individually to improve isolation of these components from each other. 
     As further shown, each connection terminal  251 A includes a link portion  2511 A and a bent portion  2512 A. The link portion  2511 A is flush with the busbar  201 A. The bent portion  2512 A is bent so as to extend in the height direction. 
     Moreover, each connection terminal  252 A includes a link portion  2521 A and a bent portion  2522 A. The link portion  2521 A is flush with the busbar  202 A. The bent portion  2522 A is bent so as to extend in the height direction. 
     Furthermore, each connection terminal  253 A includes a link portion  2531 A and a bent portion  2532 A. The link portion  2531 A is flush with the busbar  203 A. The bent portion  2532 A is bent so as to extend in the height direction. 
     With this configuration, alignment of members of the busbar device  10 A when disposed on the jig or the like can be achieved easily by using the bent portions  2512 A,  2522 A, and  2532 A. The positional relationships of the insulating sheets  101 A,  102 A,  103 A, and  104 A and the busbars  201 A,  202 A, and  203 A can be thereby fixed reliably. In addition, not only the busbars  201 A,  202 A, and  203 A but also the output terminals  261 A,  262 A, and  263 A are insulated individually, which improves isolation of these components from each other. 
     Moreover, the strip portions T 11 , T 12 , T 13 , T 14 , T 15 , and T 16  are formed in corresponding insulating sheets  101 A,  102 A,  103 A, and  104 A, which can reliably cover the output terminals  261 A,  262 A, and  263 A and also can improve the strength of mutual adhesion of the insulating sheets  101 A,  102 A,  103 A, and  104 A. 
     Third Exemplary Embodiment 
     A busbar device according to a third embodiment of the present invention will be described with reference to the drawings.  FIG. 9A  is a perspective view illustrating an external appearance of a motor  1  according to the third embodiment, which is housed in a housing  50 .  FIG. 9B  is a cross section of the motor  1  taken along line C-C in  FIG. 9A . 
     As illustrated in  FIGS. 9A and 9B , the motor  1  according to the third embodiment includes the busbar device  10 A according to the second embodiment, stators  20 , a rotor  40 , and the housing  50 . 
     As illustrated in  FIGS. 9A and 9B , the motor  1  includes multiple stators  20 , the busbar device  10 A, the rotor  40 , and the housing  50 . It is noted that the third exemplary embodiment is described by using a motor as an example. However, the motor can be substituted by a power generator. 
     The housing  50  includes a first member  51  and a second member  52 . The first member  51  has a cylindrically shaped wall  511  and a tabularly shaped wall  512  that covers one end of the cylindrically shaped wall  511 . The first member  51  is shaped like a cylindrical box having an opening. The second member  52  is shaped tabularly. The second member  52  has the tabularly shaped wall  521 . The second member  52  is disposed so as to cover the opening of the first member  51 . Accordingly, the housing  50  has a space  500  enclosed by the wall  511 , the wall  512 , and the wall  521 . The first member  51  and the second member  52  are made of a material having a high rigidity. 
     The stators  20 , the busbar device  10 A, and the rotor  40  are disposed in the space  500  defined by the housing  50 . The rotor  40  is disposed in a central region when the walls  521  and  512  are viewed in plan. In other words, the rotor  40  is disposed in the central region that has a predetermined size and that includes a central axis of the cylindrical shape formed by the wall  511 . 
     As illustrated in  FIG. 9B , multiple stators  20  are disposed between the cylindrical wall  511  of the housing  50  and the rotor  40 . The multiple stators  20  are disposed equidistantly and close to each other along the circumference of the cylindrical wall  511 . 
     The busbar device  10 A is disposed at a position close to the stators  20  in the axial direction of the housing  50 . The busbar device  10 A is connected to the stators  20 . Part of each output terminal  261  of the busbar device  10 A is taken out from the housing  50 . 
     According to this configuration, the busbar device  10 A is disposed in the state in which the positional relationships of the insulating sheets  101 A,  102 A,  103 A, and  104 A and the busbars  201 A,  202 A, and  203 A are fixed, which can simplify manufacturing of the motor  1 . In addition, the output terminal  261 A,  262 A,  263 A are covered by the insulating sheet  101 A,  102 A,  103 A, and  104 A, which can provide reliable insulation between the busbar device  10 A and the housing  50  or other components. 
     Fourth Exemplary Embodiment 
     A busbar device according to a fourth embodiment of the present invention will be described with reference to the drawings.  FIG. 10A  is a perspective view illustrating an external appearance of a busbar device  10 C according to the fourth embodiment.  FIG. 10B  is a cross section of the busbar device  10 C taken along line D-D in  FIG. 10A . 
     As illustrated in  FIGS. 10A and 10B , the busbar device  10 C according to the fourth embodiment is different from the busbar device  10  according to the first embodiment in that the busbar device  10 C is manufactured by further using a second jig  320 . Additional configurations of the busbar device  10 C are similar to those of the busbar device  10 , and the description of similar configurations will not be repeated. Although  FIGS. 10A and 10B  illustrate the insulating sheet  104  as an example, the same configuration applies to the insulating sheets  101 ,  102 , and  103 . Although  FIGS. 10A and 10B  illustrate the busbar  203  as an example, the same configuration applies to the busbars  201  and  202 . 
     The second jig  320  is shaped so as to surround the outer circumference R 1  of first portion  311  of the first jig  310 . The second jig  320  has an outer circumference R 3 . The diameter of the outer circumference R 3  is substantially equal to the diameter of inner circumference D 33  of the busbar  203 . The second jig  320  is removable from the first jig  310 . 
     The insulating sheet  104  is placed such that the inner circumference D 14  of the insulating sheet  104  follows the outer circumference R 1  of the first portion  311  (of the first jig  310 ). Moreover, the busbar  203  is placed such that the inner circumference D 33  of the busbar  203  follows the outer circumference R 3  of the second jig  320 . The second jig  320  is subsequently removed from the first jig  310 . Next, the insulating sheet  103  is placed such that the inner circumference D 13  of the insulating sheet  103  follows the outer circumference R 1  of the first portion  311  (of the first jig  310 ). The busbar  202  is placed such that the inner circumference D 32  of the busbar  202  follows the outer circumference R 3  of the second jig  320 . The above steps are repeated for the insulating sheets  101  and  102  and the busbar  201 . 
     With this configuration, the inner circumference D 31  of the busbar  201 , the inner circumference D 32  of the busbar  202 , and the inner circumference D 33  of the busbar  203  can be aligned. 
     With this configuration, when the busbar device  10  is manufactured, the insulating sheets  101 ,  102 ,  103 , and  104  and the busbars  201 ,  202 , and  203  can be aligned easily by using the first jig  310  and the second jig  320 . 
     It is noted that since the inner circumferences of the busbars  201 ,  202 , and  203  can be aligned by using the second jig  320 , the bent portions  2532  can be omitted from the connection terminals  253 . 
     Fifth Exemplary Embodiment 
     A busbar device according to a fifth embodiment of the present invention will be described with reference to the drawings.  FIG. 11A  is a perspective view illustrating an external appearance of a busbar device  10 D according to the fifth embodiment.  FIG. 11B  is a cross section of the busbar device  10 D taken along line B-B in  FIG. 11A . 
     As illustrated in  FIGS. 11A and 11B , the busbar device  10 D according to the fifth embodiment is different from the busbar device  10  according to the first embodiment in that the busbar device  10 D is formed by further using a third jig  330  and the busbar device  10 D includes connection terminals  251 D,  252 D and  253 D having different shapes. Additional configurations of the busbar device  10 D are similar to those of the busbar device  10 , and the description of similar configurations will not be repeated. 
     The third jig  330  has an arbitrary thickness and is shaped annularly. The third jig  330  has an inner circumference R 4  and an outer circumference R 5 . The outer circumference R 5  of the third jig  330  is flush with the outer circumference R 2  of the first jig  310 . A portion of the third jig  330  is removed so as to enable the output terminals  261 ,  262 , and  263  to protrude outward while manufacturing the busbar device  10 D. 
     Each connection terminal  251 D includes a bent portion  2512 D that is formed into a U-shape that extends in the height direction. Each connection terminal  252 D includes a bent portion  2522 D that is formed into a U-shape that extends in the height direction. Each connection terminal  253 D includes a bent portion  2532 D that is formed into a U-shape that extends in the height direction. 
     Similar to the above-described embodiments, the insulating sheets  101 ,  102 ,  103 , and  104  are placed so as to surround the outer circumference R 1  of the first portion  311  (of the first jig  310 ). 
     Moreover, the busbar  201  is placed such that the outside surfaces of bent portions  2512 D of the connection terminals  251  come into contact with the inner circumference R 4  of the third jig  330 . The busbar  202  is placed such that the outside surfaces of bent portions  2522 D of the connection terminals  252  come into contact with the inner circumference R 4  of the third jig  330 . Yet further, the busbar  203  is placed such that the outside surfaces of bent portions  2532 D of the connection terminals  253  come into contact with the inner circumference R 4  of the third jig  330 . 
     The first jig  310  has multiple protrusions  315  that protrude outward from the outer circumference R 2  of the second portion  312 . The output terminals  261 ,  262 , and  263  are aligned by using respective protrusions  315 . In other words, the protrusions  315  can be used to position the busbars  201 ,  202 , and  203  in a circumferential direction. 
     The bent portions  2512 D,  2522 D, and  2532 D may be omitted from the connection portions, and link portions  2511 ,  2521 , and  2531  may be used to achieve alignment. 
     With this configuration, when the busbar device  10  is manufactured, the insulating sheets  101 ,  102 ,  103 , and  104  and the busbars  201 ,  202 , and  203  can be aligned easily by using the first jig  310  and the third jig  330 . 
     In general, it is noted that the exemplary embodiments of the present invention are not limited to the embodiments described above, and the configurations of the embodiments described may be combined with or replaced by one another. 
     Moreover, while exemplary embodiments have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the invention.