Patent Publication Number: US-10770216-B2

Title: Reactor

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a new U.S. Patent Application that claims benefit of Japanese Patent Application No. 2017-047521, filed Mar. 13, 2017, the disclosure of this application being incorporated herein by reference in its entirety for all purposes. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a reactor. 
     2. Description of Related Art 
     A technology in which a reactor is contained in a reactor case, and coolant circulates through storage space in the reactor case is conventionally known (refer to, for example, Japanese Unexamined Patent Publication (Kokai) No. 2009-49082). 
     SUMMARY OF THE INVENTION 
     However, since Japanese Unexamined Patent Publication (Kokai) No. 2009-49082 uses the reactor case, the structure increases in size and manufacturing cost. 
     Therefore, it is desired to provide a reactor having improved heat dissipation and reduced manufacturing cost, without an increase in size. 
     An embodiment of this disclosure provides a reactor that includes an outer peripheral iron core, and at least three core coils contacting or connected to an inner surface of the outer peripheral iron core. Each of the core coils includes a core and a coil wound onto the core. The reactor further includes an attachment unit disposed on one end surface of the outer peripheral iron core to attach the outer peripheral iron core in a predetermined position, and at least one ventilation port formed in the attachment unit. 
     According to the embodiment, the attachment unit is attached to only the one end surface of the outer peripheral iron core, and the at least one ventilation port is formed in the attachment unit. Thus, since a fluid, e.g., air flowing through the internal space of the outer peripheral iron core and the ventilation port of the attachment unit serves to dissipate heat, the reactor has improved heat dissipation. Furthermore, it is possible to eliminate the need to provide an additional member for heat dissipation in an installed state, thus preventing an increase in the size of the reactor, while allowing reductions in the manufacturing cost and weight of the reactor. 
     The above objects, features and advantages and other objects, features and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments along with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top view of a reactor according to a first embodiment; 
         FIG. 2A  is a perspective view of a reactor according to a second embodiment; 
         FIG. 2B  is an exploded perspective view of the reactor shown in  FIG. 2A ; 
         FIG. 3  is a cross-sectional view of a reactor according to a third embodiment; 
         FIG. 4  is a cross-sectional view of a reactor according to a fourth embodiment; 
         FIG. 5A  is a perspective view of a reactor according to a fifth embodiment; 
         FIG. 5B  is another perspective view of the reactor shown in  FIG. 5A ; 
         FIG. 6A  is a perspective view of a reactor according to a sixth embodiment; 
         FIG. 6B  is an exploded perspective view of the reactor shown in  FIG. 6A ; 
         FIG. 6C  is a perspective view of an attachment unit shown in  FIG. 6B ; 
         FIG. 6D  is a side view of the reactor shown in  FIG. 6A ; 
         FIG. 7A  is a perspective view of a reactor according to a seventh embodiment; 
         FIG. 7B  is an exploded perspective view of the reactor shown in  FIG. 7A ; 
         FIG. 7C  is a top view of an attachment unit shown in  FIG. 7A ; 
         FIG. 7D  is a perspective view of the attachment unit shown in  FIG. 7B ; 
         FIG. 7E  is a side view of the reactor shown in  FIG. 7A ; 
         FIG. 8A  is an exploded perspective view of a reactor according to an eighth embodiment; 
         FIG. 8B  is an exploded perspective view of another reactor according to the eighth embodiment; 
         FIG. 9A  is an exploded perspective view of a reactor according to a ninth embodiment; 
         FIG. 9B  is an exploded perspective view of another reactor according to the ninth embodiment; and 
         FIG. 10  is a block diagram of a machine including a reactor. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Embodiments of the present invention will be described below with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same components. For ease of understanding, the drawings are modified in scale in an appropriate manner. 
       FIG. 1  is a top view of a reactor according to a first embodiment. As shown in  FIG. 1 , a reactor  5  includes an outer peripheral iron core  20  having a hexagonal cross-section and at least three core coils  31  to  33  contacting or connected to an inner surface of the outer peripheral iron core  20 . The number of cores is preferably an integral multiple of 3, and the reactor  5  can be thereby used as a three-phase reactor. Note that, the outer peripheral iron core  20  may be another polygonal shape or circular. 
     The core coils  31  to  33  include cores  41  to  43  and coils  51  to  53  wound onto the cores  41  to  43 , respectively. Each of the outer peripheral iron core  20  and the cores  41  to  43  is made by stacking iron sheets, carbon steel sheets or electromagnetic steel sheets, or made of a pressed powder core. 
     As shown in  FIG. 1 , the cores  41  to  43  have approximately the same dimensions as each other, and are arranged at approximately equal intervals in the circumferential direction of the outer peripheral iron core  20 . In  FIG. 1 , the cores  41  to  43  are in contact or integral with the outer peripheral iron core  20  at their radial outer end portions. 
     Furthermore, the cores  41  to  43  converge toward the center of the outer peripheral iron core  20  at their radial inner end portions, each having an edge angle of approximately 120°. The radial inner end portions of the cores  41  to  43  are separated from each other by gaps  101  to  103 , which can be magnetically coupled. 
     In other words, in the first embodiment, the radial inner end portion of the core  41  is separated from the radial inner end portions of the two adjacent cores  42  and  43  by the gaps  101  and  103 , respectively. The same is true for the other cores  42  and  43 . Note that, the gaps  101  to  103  ideally have the same dimensions, but may have different dimensions. In embodiments described later, a description regarding the gaps  101  to  103 , the core coils  31  to  33 , and the like may be omitted. 
     As described above, in the first embodiment, the core coils  31  to  33  are disposed inside the outer peripheral iron core  20 . In other words, the core coils  31  to  33  are surrounded by the outer peripheral iron core  20 . The outer peripheral iron core  20  can reduce leakage of magnetic flux generated by the coils  51  to  53  to the outside. 
       FIG. 2A  is a perspective view of a reactor according to a second embodiment.  FIG. 2B  is an exploded perspective view of the reactor shown in  FIG. 2A . As shown in the drawings, an attachment unit  60  is attached to one end surface of an outer peripheral iron core  20  or the end surfaces of cores  41  to  43 . The attachment unit  60  includes an end plate  61  and a cylindrical extension portion  62 . The extension portion  62  is disposed with respect to the center of the end plate  61  so as to extend in the perpendicular direction of the end plate  61 , and has an outer shape corresponding to the outer peripheral iron core  20 . Since the end plate  61  is attached to an attachment surface of a non-illustrated other member, the attachment unit  60  serves to attach the outer peripheral iron core  20  or the cores  41  to  43  in a predetermined position or positions. 
     In a side wall of the extension portion  62  of the attachment unit  60 , at least one, e.g., three ventilation ports, e.g., notches  65  are formed, as shown in  FIGS. 2A and 2B . As shown in the drawings, when the outer peripheral iron core  20  has a hexagonal cross-section, the extension portion  62  having the notches  65  also forms a hexagonal cross-section. When the outer peripheral iron core  20  has a polygonal cross-section, the extension portion  62  is preferably removed at portions corresponding to a middle side of each of three adjacent sides in cross-section of the extension portion  62 , to form the notches  65 . This facilitates forming the notches  65 . 
     When a plurality of notches  65  are formed, the notches  65  are preferably formed at equal intervals in the circumferential direction. This allows the outer peripheral iron core  20  to be stably attached to the extension portion  62 . 
     The attachment unit  60  is attached to the end surface of the outer peripheral iron core  20  or the end surfaces of the cores  41  to  43  only on one side, while the peripheral surface and the other end surface of the outer peripheral iron core  20  are exposed. The at least one ventilation port, e.g., notches  65  are formed in the attachment unit  60 . Thus, fluid, e.g., air passes through the internal space of the outer peripheral iron core  20  and the ventilation ports  65  of the attachment unit  60 , and thereby dissipating heat from the coils  51  to  53 , when the reactor  5  is driven. Therefore, the reactor  5  has improved heat dissipation. Consequently, heat dissipation of the reactor  5  can be improved. Since the notches  65  are merely formed in portions of the attachment unit  60  for securing the outer peripheral iron core  20 , it is possible to eliminate the need to provide another component in the reactor  5 . This prevents an increase in the size of the reactor  5 , while allowing for a reduction in the weight of the reactor  5 . Instead of the notches  65 , through holes or slots may be formed in the extension portion  62  as ventilation ports. In this case, the same effects as described above can be obtained. 
       FIG. 3  is a cross-sectional view of a reactor according to a third embodiment. In  FIG. 3 , a reactor  5  includes an approximately octagonal outer peripheral iron core  20  and four core coils  31  to  34  contacting or connected to an inner surface of the outer peripheral iron core  20 , in the same manner as described above. The core coils  31  to  34  are arranged at approximately equal intervals in the circumferential direction of the reactor  5 . The number of cores is preferably an even number greater than 4, and the reactor  5  can be thereby used as a single-phase reactor. 
     As is apparent from the drawing, the core coils  31  to  34  include cores  41  to  44  extending in the radial direction and coils  51  to  54  wound onto the cores  41  to  44 , respectively. The cores  41  to  44  are in contact or integral with the outer peripheral iron core  20  at their radial outer end portions. 
     Furthermore, the radial inner end portions of the cores  41  to  44  are disposed in the vicinity of the center of the outer peripheral iron core  20 . In  FIG. 3 , the cores  41  to  44  converge toward the center of the outer peripheral iron core  20  at their radial inner end portions, each having an edge angle of approximately 90°. The radial inner end portions of the cores  41  to  44  are separated from each other by gaps  101  to  104 , which can be magnetically coupled. 
     Furthermore,  FIG. 4  is a cross-sectional view of a reactor according to a fourth embodiment. In  FIG. 4 , a reactor  5  includes a round outer peripheral iron core  20  and six core coils  31  to  36 . The core coils  31  to  36  include cores  41  to  46  and coils  51  to  56  wound onto the cores  41  to  46 , respectively. The cores  41  to  46  are in contact or integral with an inner surface of the outer peripheral iron core  20 . A central core  10  is disposed at the center of the outer peripheral iron core  20 . The central core  10  is formed in the same manner as the outer peripheral iron core  20 . Each of gaps  101  to  106 , through which magnetic connection can be established, is formed between each of radial inner end portions of the cores  41  to  46  and the central core  10 . 
     The above-described attachment unit  60  is attached to an end surface of the outer peripheral iron core  20  on one side, end surfaces of the cores  41  to  46  on one side, or an end surface of the central core  10  on one side as shown in  FIG. 3 or 4 . Such reactors  5  have improved heat dissipation, for the same reason as described above. 
     The reactor  5  having the structure shown in  FIG. 1  will be described below in more detail. The following description is generally applicable to the reactors  5  shown in  FIGS. 3 and 4  as well. 
       FIG. 5A  is a perspective view of a reactor according to a fifth embodiment.  FIG. 5B  is another perspective view of the reactor shown in  FIG. 5A . As shown in the drawing, a through hole  66  is formed in the middle of an end plate  61 . The through hole  66  is formed in a position approximately corresponding to an inner peripheral surface of an outer peripheral iron core  20 , and in approximately the same shape as the inner peripheral surface of the outer peripheral iron core  20 . In this case, since heat dissipates through the through hole  66 , the reactor  5  has improved heat dissipation. Furthermore, the through hole  66  serves to reduce the weight of the reactor  5 . A plurality of through holes may be formed in an area of the end plate  61  corresponding to the outer peripheral iron core  20 . Furthermore, a plurality of through holes may be formed between the outer peripheral iron core  20  and each of cores  41  to  43 . A through hole may be formed in a portion of the end plate  61  corresponding to the axial direction of the outer peripheral iron core  20  or the cores  41  to  43 . Forming the through holes in such positions has reduced effects on magnetic flux. Thus, holes may be formed in such positions of the outer peripheral iron core  20  or the cores  41  to  43 , as described later. 
       FIG. 6A  is a perspective view of a reactor according to a sixth embodiment.  FIG. 6B  is an exploded perspective view of the reactor shown in  FIG. 6A . In the drawings, a square through hole  66  is formed in an end plate  61  of an attachment unit  60 . A cooling fan  6  having a shape corresponding to the through hole  66  is attached to the through hole  66 . The cooling fan  6  is driven by a non-illustrated motor. 
     As can be understood from  FIG. 6A , the bottom of the cooling fan  6  is preferably flush with the bottom surface of the end plate  61 . As shown in  FIG. 6C , which is a perspective view of the attachment unit shown in  FIG. 6B , the top of the cooling fan  6  attached to the end plate  61  is lower than the top surface of an extension portion  62 .  FIG. 6D  is a side view of the reactor shown in  FIG. 6A . As shown in  FIG. 6D , an outer peripheral iron core  20 , which has coils  51  to  53  wound onto cores  41  to  43 , is attached to the attachment unit  60  with screws  81  and  82 , as described later. Therefore, the cooling fan  6  is positioned under the coils  51  to  53 . 
     When the cooling fan  6  is driven, a current of air blows directly from the cooling fan  6  onto the coils  51  to  53 , and flows through gaps  101  to  103  in the axial direction of the outer peripheral iron core  20 . This improves the heat dissipation of the reactor  5 . In this case, since the air directly blows from the cooling fan  6  onto the coils  51  to  53 , the cooling effect is further improved. 
       FIG. 7A  is a perspective view of a reactor according to a seventh embodiment.  FIG. 7B  is an exploded perspective view of the reactor shown in  FIG. 7A . In the drawings, a square through hole  66  that is smaller than the above-described through hole is formed in an end plate  61  of an attachment unit  60 . A cooling fan  6  having a shape corresponding to the through hole  66  is attached to the through hole  66 . The cooling fan  6  is driven by a non-illustrated motor. 
       FIG. 7C  is a top view of the attachment unit shown in  FIG. 7A . For ease of understanding, coils  51  to  53  in a state of attaching the attachment unit  60  to the outer peripheral iron core  20  are illustrated in  FIG. 7C . A triangular area A is formed on radial inner sides of the coils  51  to  53 . As a matter of course, the shape of the area A differs depending on the number of coils, and the area A generally has a polygonal shape having the same number of sides as the number of coils. The cooling fan  6  and the through hole  66  are disposed in the area A. 
       FIG. 7D  is a perspective view of the attachment unit shown in  FIG. 7B . When the cooling fan  6  is attached to the end plate  61  in the same manner as described above, the top of the cooling fan  6  is approximately flush with a top surface of an extension portion  62 .  FIG. 7E  is a side view of the reactor shown in  FIG. 7A . As shown in  FIG. 7E , the outer peripheral iron core  20 , which has the coils  51  to  53  wound onto cores  41  to  43 , is attached to the attachment unit  60 . Thus, the bottoms of the coils  51  to  53  are positioned in the vicinity of the end plate  61 , and the top of the cooling fan  6  is positioned higher than the bottoms of the coils  51  to  53 . 
     When the cooling fan  6  is driven, a current of air flows from the cooling fan  6  through gaps  101  to  103  in the axial direction of the outer peripheral iron core  20 . In this case, since the cooling fan  6  is disposed in such a position as not to interfere with the coils  51  to  53 , the height of the extension portion  62  can be lowered. As a result, it is possible to prevent an increase in the size of the whole reactor  5 . 
       FIG. 8A  is an exploded perspective view of a reactor according to an eighth embodiment. As shown in  FIG. 8A , at least one hole  70  extending in the axial direction is formed in an outer peripheral iron core  20  at equal intervals in the circumferential direction. A hollow rod  80  having a screw thread formed in an inner peripheral surface thereof is inserted into the hole  70 . The rod  80  has approximately the same length as the outer peripheral iron core  20  in the axial direction. The rod  80  serves as a connection rod for connecting between an attachment unit  60  and the outer peripheral iron core  20 . The hole  70  is formed in such a portion of the outer peripheral iron core  20  so as to have little effect on magnetic flux. In the same manner, a hole  70  may be formed in such a portion of cores  41  to  46  so as to have little effect on magnetic flux. 
     As is apparent from  FIGS. 7C and 7D , in particular, holes  71  are formed in an extension portion  62  of the attachment unit  60 . The ends of the rods  80  are disposed on the holes  71  of the extension portion  62 , and screws  82  are screwed into the rods  80 . In the same manner, screws  81  are screwed into the other ends of the rods  80  on an end surface of the outer peripheral iron core  20  on the far side from the attachment unit  60 . Therefore, the attachment unit  60  and the outer peripheral iron core  20  can be connected without an increase in size. 
       FIG. 8B  is an exploded perspective view of another reactor according to the eighth embodiment. In  FIG. 8B , long screws  90 , which function as connection rods, penetrate through holes  70  of an outer peripheral iron core  20 , and tip ends of the long screws  90  are screwed into holes  71  of an extension portion  62 . For this purpose, threading is cut in inner surfaces of the holes  71 . In this case, the same effects as described above can be obtained, while the number of components can be lower than in  FIG. 8A . 
       FIG. 9A  is an exploded perspective view of a reactor according to a ninth embodiment. In  FIG. 9A , a ring member  69  is disposed on an end surface of an outer peripheral iron core  20  on the opposite side to an attachment unit  60 . The ring member  69  is preferably formed in the same manner as the outer peripheral iron core  20 . The axial length of the ring member  69  is preferably longer than the protrusion length of coils  51  to  53  protruding from the end surface of the outer peripheral iron core  20 . Through holes  75  are formed in the ring member  69  in positions corresponding to holes  70  of the outer peripheral iron core  20 . The length of each rod  80  shown in  FIG. 9A  approximately corresponds to the sum of the axial length of the outer peripheral iron core  20  and the axial length of the ring member  69 . 
     In the same manner as described above, the ends of the rods  80  inserted into the holes  70  of the outer peripheral iron core  20  are disposed on holes  71  of an extension portion  62 , and screws  82  are screwed into the rods  80 . In the same manner, screws  81  are screwed into the other ends of the rods  80  penetrating through the through holes  75  of the ring member  69 . Therefore, the attachment unit  60 , the outer peripheral iron core  20 , and the ring member  69  can be connected without an increase in size. 
       FIG. 9B  is an exploded perspective view of another reactor according to the ninth embodiment. In  FIG. 9B , long screws  90  penetrate through holes  75  of a ring member  69  and holes  70  of an outer peripheral iron core  20 , and tip ends of the long screws  90  are screwed into holes  71  of an extension portion  62 . In this case, the same effects as described above can be obtained. 
       FIG. 10  is a block diagram of a machine including a reactor. In  FIG. 10 , a reactor  5  is used in a motor driver or a power conditioner. The machine includes the motor driver or the power conditioner. In this case, the motor driver, power conditioner, machine, and the like having the reactor  5  can be easily provided. The scope of the present invention includes appropriate combinations of some of the above-described embodiments. 
     Aspects of Disclosure 
     A first aspect provides a reactor ( 5 ) that includes an outer peripheral iron core ( 20 ), and at least three core coils ( 31 - 36 ) contacting or connected to an inner surface of the outer peripheral iron core. Each of the core coils includes a core ( 41 - 46 ) and a coil ( 51 - 56 ) wound onto the core. The reactor further includes an attachment unit ( 60 ) disposed on one end surface of the outer peripheral iron core, for attaching the outer peripheral iron core in a predetermined position, and at least one ventilation port ( 65 ) formed in the attachment unit. 
     According to a second aspect, the first aspect further includes a central core ( 10 ) disposed at the center of the outer peripheral iron core. 
     According to a third aspect, in the first or second aspect, the attachment unit includes an end plate and an extension portion extending in a perpendicular direction of the end plate, and a through hole ( 66 ) is formed in a portion of the end plate corresponding to an axial direction of the outer peripheral iron core or the cores. 
     According to a fourth aspect, the third aspect further includes a cooling fan ( 6 ) attached to the through hole. 
     According to a fifth aspect, in the fourth aspect, the cooling fan is disposed on radial inner sides of the coils of the at least three core coils. 
     According to a sixth aspect, in any one of the first to fifth aspect, the outer peripheral iron core has a hole ( 70 ) extending in an axial direction, and the attachment unit and the outer peripheral iron core are connected with a connection rod ( 80 ,  90 ) inserted into the hole. 
     Advantageous Effects of the Aspects 
     According to the first aspect, the attachment unit is attached to only one end surface of the outer peripheral iron core, and the at least one ventilation port is formed in the attachment unit. Thus, since fluid, e.g., air flowing through the internal space of the outer peripheral iron core and the ventilation port of the attachment unit serves to dissipate heat, the reactor has improved heat dissipation. Furthermore, it is possible to eliminate the need to provide an additional member for heat dissipation in an installed state, thus preventing an increase in the size of the reactor while allowing a reduction in the weight of the reactor. Furthermore, since a reactor case is not required, the reactor can be manufactured at a reduced cost. 
     According to the second aspect, even if the reactor has a central core, the reactor has improved heat dissipation. 
     According to the third aspect, since heat dissipates through the through hole formed in the portion of the end plate, the reactor has improved heat dissipation. Furthermore, the reactor has a reduced weight. 
     According to the fourth aspect, the cooling fan improves the heat dissipation of the reactor. 
     According to the fifth aspect, since the cooling fan does not interfere with the coils, the height of the extension portion can be lowered. 
     According to the sixth aspect, the attachment unit and the outer peripheral iron core can be connected without an increase in size. 
     The present invention is described above with reference to the preferred embodiments, but it is apparent for those skilled in the art that the above modifications and other various modifications, omissions, and additions can be performed without departing from the scope of the present invention.