Patent Publication Number: US-2015061804-A1

Title: Reactor unit

Description:
TECHNICAL FIELD 
     The present invention relates to a reactor unit. 
     BACKGROUND ART 
     Currently, a reactor made by winding a coil around a magnetic core is used as a component of a DC-DC converter to be installed in hybrid cars, electric cars, fuel cell cars, etc. In recent years, the technique of providing a radiator (fin) for such reactor itself, which has a magnetic core and a coil, and immersing the radiator in a cooling medium has been proposed (see, for example, Patent Document 1). 
     PRIOR ART REFERENCE 
     Patent Document 
     Patent Document 1: JP2010-118610 A 
     SUMMARY OF THE INVENTION 
     Problem to be Solved by the Invention 
     A conventional reactor, as in the one described in Patent Document 1, is bonded to a cooling base having an interior space filled with a cooling medium (cooling water) and the bonded part thereof is usually sealed with an O-ring or the like. If a torsional force is exerted on the cooling base, however, the bonded surface (sealed surface) with the reactor becomes distorted, which could cause leakage of the cooling medium within the cooling base. The same problem could also occur in the case of fixing the reactor to the cooling base with a bolt. 
     The present invention has been made in view of the above-described circumstances. An object of the present invention is to maintain, in a reactor unit having a reactor and a base, the bonded state between the reactor and the base even if a torsional force is exerted on the base. 
     Means for Solving the Problem 
     In order to achieve the above object, a reactor unit according to the present invention comprises a reactor and a base to which the reactor is attached, wherein the base has a base-side bonding surface to be bonded to a bonding surface of the reactor, and wherein the base is configured such that a portion not including the base-side bonding surface has a thickness smaller than that of a portion including the base-side bonding surface. 
     By adopting the above configuration, the base is configured such that a portion not including the base-side bonding surface to be bonded to the bonding surface of the reactor has a thickness smaller than that of a portion including the base-side bonding surface. As a result, if a torsional force is exerted on the base, it is possible to allow such torsion to occur first in the portion not including the base-side bonding surface (thin portion), and an occurrence of torsion in the portion including the base-side bonding surface (thick portion) can thereby be suppressed. Accordingly, the bonded state between the reactor and the base can be maintained even if a torsional force is exerted on the base. 
     In the reactor unit according to the present invention, the portion not including the base-side bonding surface may have a reinforced region. 
     By adopting the above configuration, the strength of the portion not including the base-side bonding surface (thin portion) can be ensured. 
     Further, in the reactor unit according to the present invention, the base may have a fixation screw for fixing the base to a predetermined structure, and the region where the fixation screw is provided may serve as the reinforced region. 
     By adopting the above configuration, the region including the fixation screw, which is configured to be relatively thick, can be used as a region acting as the reinforced region. 
     Further, in the reactor unit according to the present invention, it is possible to adopt a base having a first base to which a first reactor is attached and a second base to which a second reactor is attached, wherein the first and second bases are connected in communication with each other via a flow path through which a cooling medium flows, the cooling medium being in contact with a radiator provided in the first and second reactors. In that case, the region where the flow path is provided may serve as the reinforced region. 
     By adopting the above configuration, the region including the flow path, which is configured to be relatively thick, can be used as a region acting as the reinforced region. 
     Further, in the reactor unit according to the present invention, it is preferable to provide a rib for the reinforced region and to set the height of the rib so as not to reach the base-side bonding surface 
     By adopting the above configuration, since the height of the rib provided in the reinforced region is set in advance so as not to reach the base-side bonding surface, the rib does not interfere when bonding the bonding surface of the reactor to the base-side bonding surface of the base. As a result, the step of adjusting the height of the rib (trimming is not needed when attaching the reactor to the base, and this improves workability. 
     Further, in the reactor unit according to the present invention, the thickness of the portion not including the base-side bonding surface may be made smaller than that of the portion including the base-side bonding surface by cutting out a side surface of the base. 
     By adopting the above configuration, even in the case where cutting out the surface of the base is difficult due to the positional relationship between the reactor and other structures, a thin portion (portion not including the base-side bonding surface) can be easily formed by cutting out the side surface of the base. 
     Further, in the reactor unit according to the present invention, the base-side bonding surface may be formed at both ends in the thickness direction of the portion including the base-side bonding surface. In that case, the portion not including the base-side bonding surface is preferably connected and joined to the portion including the base-side bonding surface, approximately at the center in the thickness direction thereof. 
     By adopting the above configuration, a torsion moment from the portion not including the base-side bonding surface (thin portion) is transferred substantially evenly to the base-side bonding surfaces formed at both ends in the thickness direction of the portion including the base-side bonding surface (thick portion). Accordingly, it is possible to suppress the transfer of a large torsional moment to only one of the base-side bonding surfaces. 
     The reactor unit according to the present invention may further have a switching device or a capacitor. 
     Effect of the Invention 
     According to the present invention, in a reactor unit having a reactor and a base, the bonded state between the reactor and the base can be maintained even if a torsional force is exerted on the base. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of a reactor unit according to an embodiment of the present invention (in a state where a reactor is not attached to a base). 
         FIG. 2  is a cross-sectional view of the reactor unit shown in  FIG. 1  (in a state where the reactor has been attached to the base) along the line II-II. 
         FIG. 3  is a cross-sectional view of the reactor unit shown in  FIG. 1  (in a state where the reactor has been attached to the base) along the line III-III. 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     Hereinafter, a reactor unit  1  according to an embodiment of the present invention will be described, with reference to the drawings. 
     The reactor unit  1  according to this embodiment is used as a component of a DC-DC converter for a fuel cell vehicle. As shown in  FIGS. 1 to 3 , the reactor unit  1  has a reactor  10  and a base  20  to which the reactor  10  is attached. 
     The reactor  10  has: a cylindrical body  11  formed by winding a coil around a magnetic core; and a cover  12  that covers the cylindrical body  11 . In this embodiment, as shown in  FIGS. 2 and 3 , two cylindrical bodies  11  are arranged to be lined up in the lateral direction (horizontal direction) and a synthetic resin (an epoxy resin, urethane resin, PPS resin, PBT resin, ABS resin, etc.) is provided to cover the outside of the two cylindrical bodies  11 , thereby forming the cover  12  having an approximately cuboidal shape. 
     A radiator  13  made of metal is provided on a surface of the cover  12  of the reactor  10 , which faces the base  20 . The radiator  13  is a portion which is to be immersed in a cooling medium C introduced into the base  20 . Heat generated at the magnetic core and coil of the reactor  10  is transferred to the cooling medium C via the radiator  13 , and the cooling of the reactor  10  can accordingly be achieved. In this embodiment, the reactors  10  are arranged vertically above and below the base  20  and two pairs of such vertically arranged reactors  10  are arranged to be lined up in the lateral direction (horizontal direction). 
     As shown in  FIGS. 1 and 3 , the base  20  includes: a first base  21  to which a first pair of vertically arranged reactors  10  is attached; a second base  22  to which a second pair of vertically arranged reactors  10  is attached; a base connector  23  that connect the first base  21  and the second base  22 ; and a wall connector  24  that connects the first base  21  and a specific outer wall W. 
     As shown in  FIGS. 1 and 2 , the first base  21  and the second base  22  are connected in communication with each other via a flow path  25  through which the cooling medium C, which is in contact with the radiator  13  provided in the reactor  10 , flows. The flow path  25  constitutes a part of the base connector  23  and is configured such that the thickness (the size in the vertical direction) thereof is slightly greater than that of the base connector  23 . Accordingly, the region where the flow path  25  is provided in the base connector  23  serves as a reinforced region. It should be noted that an external flow path P is connected to the flow path  25  so that the cooling medium C is introduced into the flow path  25  through the external flow path P. 
     As shown in  FIGS. 1 to 3 , the first and second bases  21  and  22  which constitute the base  20  have, at both ends in the thickness direction thereof, base-side bonding surfaces  21   a  and  22   a  which are to be bonded to bonding surfaces  14  of the reactors  10 . As shown in  FIG. 3 , the base connector  23 , which is a portion not including the base-side bonding surfaces  21   a  and  22   a , is configured so as to be thinner than the first and second bases  21  and  22 , which are portions including the base-side bonding surfaces  21  a and  22   a . Further, as shown in  FIG. 3 , the base connector  23  is connected and joined to the first and second bases  21  and  22 , approximately at the center in the thickness direction thereof. 
     The first base  21  of the base  20  has a portion spaced apart from the outer wall W and a portion close to the outer wall W, as shown in  FIG. 1 . In the wall connector  24 , as shown in  FIG. 3 , a portion (spaced portion)  24   a  connecting the outer wall W with the portion of the first base  21  spaced apart from the outer wall W is configured so as to have a thickness smaller than that of the first base  21  by cutting the surfaces (upper and lower surfaces) of the spaced portion  24   a . Further, as shown in  FIG. 3 , the spaced portion  24   a  of the wall connector  24  is connected and joined to the first and second bases  21  and  22 , approximately at the center in the thickness direction thereof. On the other hand, as shown in  FIG. 2 , a portion (close portion)  24   b  of the wall connector  24 , which connects the outer wall W with the portion of the first base  21  close to the outer wall W, is configured so as to have a thickness smaller than that of the first base  21  by cutting a side surface thereof. 
     As shown in  FIGS. 1 and 3 , a plurality of ribs  26  is provided in the base connector  23  and the wall connector  24  which constitute the base  20 . In the base connector  23  and the wall connector  24 , which are configured to be thinner than the first and second bases  21  and  22 , the regions having such ribs  26  serve as reinforced regions. In this embodiment, the height of the ribs  26  is set so as not to reach the base-side bonding surfaces  21  a and  22   a  of the first and second bases  21  and  22 . 
     As shown in  FIG. 1 , the first and second bases  21  and  22  which constitute the base  20  have a plurality of fixation screws  27  for fixing the first and second bases  21  and  22  to a predetermined structure. Such fixation screw  27  is also provided in the wall connector  24 . In the wall connector  24 , the region where the fixation screw is provided is configured so as to be thicker than other regions, and such region serves as a reinforced region. 
     In the reactor unit  1  according to the embodiment described above, the base connector  23  and the wall connector  24  (portions not including the base-side bonding surfaces  21   a  and  22   a  to be bonded to the bonding surfaces  14  of the reactors  10 ) of the base  20  are configured so as to have a thickness smaller than that of the first and second bases  21  and  22  (portions including the base-side bonding surfaces  21   a  and  22   a ). As a result, if a torsional force is exerted on the base  20 , it is possible to allow such torsion to occur first in the thin base connector  23  and wall connector  24 , and an occurrence of torsion in the thick first and second bases  21  and  22  can thereby be suppressed. Accordingly, the bonded state between the reactor  10  and the base  20  can be maintained even if a torsional force is exerted on the base  20 . 
     Further, in the reactor unit  1  according to the embodiment described above, the base connector  23  and the wall connector  24  have reinforced regions (flow path  25 , ribs  26  and fixation screws  27 ). As a result, the strength of the thin base connector  23  and wall connector  24  can thereby be ensured. In particular, in this embodiment, the flow path  25 , which is configured so as to be relatively thick, and the fixation screw  27 , which is also configured so as to be relatively thick, can be used as regions acting as reinforced regions. 
     Further, in the reactor unit  1  according to the embodiment described above, the height of the ribs  26  provided in the reinforced region is set in advance so as not to reach the base-side bonding surfaces  21   a  and  22   a . As a result, the ribs  26  do not interfere when the bonding surface  14  of the reactor  10  is bonded to the base-side bonding surfaces  21   a  and  22   a  of the base  20 . Accordingly, the step of adjusting the height of the ribs (trimming) is not needed when attaching the reactor  10  to the base  20 , which improves workability. 
     Further, in the reactor unit  1  according to the embodiment described above, the thickness of the wall connector  24  can be reduced relative to the thickness of the first base  21  by cutting out a side surface of the close portion  24   b  of the wall connector  24 . In other words, even in the case where cutting out the surfaces (upper and lower surfaces) of the wall connector  24  is difficult because the reactor  10  is close to the outer wall W, a thin portion can easily be formed by cutting out the side surface of the close portion  24   b  of the wall connector  24 . 
     Further, in the reactor unit  1  according to the embodiment described above, the base bonding surfaces  21   a  and  22   a  are formed at both ends in the thickness direction of the first and second bases  21  and  22 , and the base connector  23  and the wall connector  24  are connected and joined to the first and second bases  21  and  22 , approximately at the center in the thickness direction thereof. As a result, a torsional moment from the base connector  23  or from the wall connector  24  is transferred substantially evenly to the base-side bonding surfaces  21   a  and  22   a  formed at both ends in the thickness direction of the first and second bases  21  and  22 . Accordingly, it is possible to suppress the transfer of a large torsional moment to either of the base-side bonding surfaces. 
     Although the above-described embodiment describes an example in which the reactors  10  are arranged above and below the base  20 , the reactor  10  may be arranged only above (or below) the base  20 . Further, although this embodiment describes an example in which two pairs of vertically arranged reactors  10  are arranged to be lined up in the lateral (horizontal) direction, three or more pairs of reactors  10  may be arranged to be lined up in the lateral direction. Furthermore, the reactor unit  1  may have a switching device and a capacitor. 
     Although the above-described embodiment describes an example in which the reactor unit according to the present invention is installed in a fuel cell vehicle, the reactor unit according to the present invention may be installed in various types of moving objects other than fuel cell vehicles (hybrid cars, electric cars, robots, ships, airplanes, etc.). 
     The present invention is not limited to the above-described embodiment. Design modifications to the above embodiment, which will be made by a person skilled in the art as appropriate, are also included in the scope of the present invention, as long as they have the features of the present invention. In other words, each element in the above embodiment and the arrangement, materials, conditions, shapes, dimensions, etc., thereof are not limited to those described above and may be modified as appropriate. In addition, each element in the embodiment may be combined, as long as such combination is technically possible, and such combination is also included in the scope of the present invention as long as it has the features of the present invention. 
     DESCRIPTION OF REFERENCE NUMERALS 
       1  . . . reactor unit;  10  . . . reactor;  14  . . . bonding surface (of reactor);  20  . . . base;  21  . . . first base (portion including base-side bonding surface);  22  . . . second base (portion including base-side bonding surface);  21   a ,  22   a  . . . base-side bonding surface;  23  . . . base connector (portion not including base-side bonding surface);  24  . . . wall connector (portion not including base-side bonding surface);  25  . . . flow path;  26  . . . rib; and  27  . . . fixation screw