Abstract:
A new electrical junction box in which even if a plurality of bolts are connected to external electrical cables, an external electrical power supply cable from a jump starter can be surely connected to a target connecting bolt, thereby avoiding a problem of an error in coupling by a simple structure. A coupling error check wall is provided around an alternator connecting bolt. An alligator clip for jump starting is prevented to be connected to the alternator connecting bolt. The alligator clip for jump starting is permitted to be connected to a battery connecting bolt.

Description:
BACKGROUND 
       [0001]    This invention relates to an electrical junction box to be mounted on a motor vehicle, and more particularly relates to an electrical junction box provided with connecting bolts to which electrical power supply terminals are coupled. 
         [0002]    Heretofore, an electrical junction box such as a fuse box, to which electrical power supply terminals from a battery are connected, is installed in an engine room in a motor vehicle to obtain good maintenance of electrical power supply paths in the motor vehicle and to efficiently branch an electrical power source. 
         [0003]    When a battery becomes a superdischarged condition in a motor vehicle, the electrical junction box provided with a relief hardware structure has been proposed so that the battery under the superdischarged condition receives electrical power supply from a battery in another motor vehicle or an emergency potable electrical power source (hereinafter referred to “a jump starter”) to start an engine. Such a relief terminal hardware structure has been disclosed in, for example, JP 2004-134278 A and JP 2008-123928 A. In particular, in a current hybrid type motor vehicle or the like, since it is difficult to install an upsized battery in an engine room, the battery can be disposed in a trunk room or the like different from the engine room. In this case, if an electrical junction box provided with the relief terminal hardware structure is installed in the engine room, it will be possible to deal with the discharged battery merely by opening a hood of the engine room. Accordingly, such electrical junction box has been available. 
         [0004]    However, in the above electrical junction box, a relief terminal must be specially made of a bus bar, and in addition, a distinguishable cover member that protects the relief terminal must be provided in the electrical junction box in order to prevent an error in coupling. Accordingly, this will increase the number of parts and will involve complicated steps in production. 
         [0005]    It may be considered that an external electrical power supply cable is connected to a connecting bolt, to which a feeder from a battery is connected, to receive an electrical power supply from the jump starter in the electrical junction box. However, the electrical junction box such as a fuse box that receives the electrical power supply from the battery is provided with a plurality of connecting bolts such as a starter connecting bolt to which a feeder to a starter is connected, and an alternator connecting bolt to which a feeder from an alternator is connected, as well as a battery connecting bolt to which a feeder from a battery is connected. Accordingly, there is a possibility that an external electrical power supply cable from the jump starter may be connected to another connecting bolt by mistake. Particularly, if the external electrical power supply cable from the jump starter is connected to the alternator bolt connected to a feeder from the alternator, a load is applied to the alternator and its function will be lowered. 
         [0006]    The exemplary embodiments of the invention address the above problems and other problems by, for example, providing a new electrical junction box in which even if a plurality of bolts are connected to external electrical cables, an external electrical power supply cable from a jump starter can be surely connected to a target connecting bolt, thereby avoiding a problem of an error in coupling by a simple structure. 
         [0007]    In an exemplary embodiment an electrical junction box includes: a battery connecting bolt to which a feeder from a battery is connected, and an alternator connecting bolt to which a feeder to an alternator is connected. A coupling error check wall is provided around the alternator connecting bolt to restrain a space around the alternator connecting bolt. A feeder terminal to an alternator and a fixing nut are permitted to be mounted on the alternator connecting bolt and an alligator clip for jump starter is prevented to be connected to the alternator connecting bolt. A space around the battery connecting bolt is set to be larger than the space around the alternator connecting bolt to permit the alligator clip for jump starter to be connected to the battery connecting bolt. 
         [0008]    When the battery reaches a superdischarged condition, an external electrical power supply cable (an alligator clip for jump starter) is connected to the battery connecting bolt to which a battery terminal is attached so as to supply an electrical power to the superdischarged battery in the electrical junction box installed in the engine room. Accordingly, it is possible to supply an external electrical power to the superdischarged battery merely by connecting the alligator clip for jump starter to the conventional battery connecting bolt without providing any special relief terminal for the superdischarged battery. 
         [0009]    In addition, since the coupling error check wall is provided on the space around the alternator connecting bolt, it is possible to prevent the alligator clip for jump starter from being connected to the alternator connecting bolt by mistake and to avoid a lower performance of the alternator based on excessive load to the alternator upon an error in coupling. It is preferable that the coupling error check wall is provided on each of opposite sides of the alternator connecting bolt. It is more preferable that the coupling error check wall is provided to surround three sides of the alternator connecting bolt. 
         [0010]    Particularly, because the coupling error check wall is provided on the space around the alternator connecting bolt so that the feeder is permitted to be connected to the alternator connection bolt and the alligator clip for jump starter is prevented from being connected to the alternator connecting bolt, it is possible to easily connect the feeder terminal to the alternator and to completely prevent the alligator clip for jump starter from being connected to the alternator connecting bolt. 
         [0011]    In an exemplary embodiment, the coupling error check wall protrudes over an end of the alternator connecting Thus, it is possible to prevent the protruding end of a shaft portion of the alternator connecting bolt from protruding outward (upward) from a protruding end of the coupling error check wall. 
         [0012]    Because the coupling error check wall is provided around the alternator connecting bolt, it is possible to positively connect the external electrical power supply cable from the jump starter to the target battery connecting bolt, thereby avoiding the error in coupling. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a plan view of an embodiment of an electrical junction box in accordance with the exemplary embodiments illustrating the electrical junction box from which an upper cover is removed; and 
           [0014]      FIG. 2  is a section view taken along lines II-II in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0015]    Referring now to the drawings, embodiments of an electrical junction box in accordance with the present invention will be described below. 
         [0016]      FIGS. 1 and 2  show an embodiment of an electrical junction box  10 . The electrical junction box  10  includes an electrical junction box main body  12 , an upper cover (not shown) to be incorporated in the main body  12  from an upper side, and a lower cover  14  to be incorporated in the main body  12  from a lower side. The electrical junction box  10  is attached through a bracket (not shown) to an engine room in a motor vehicle. Hereinafter, a vertical direction designates upper and lower directions in  FIG. 2  in principle. 
         [0017]    Specifically, the electrical junction box main body  12  is provided with a fuse mounting section  16 , on which fuses (not shown) are mounted, and is formed into a rectangular block-like configuration, as a whole. Bus bars  18  that constitute internal circuits connected to the fuses are installed in the electrical junction box main body  12 . 
         [0018]    The bus bars  18  are provided with terminal sections  20   a  and  20   b  that are exposed outward so that the terminal sections  20   a  and  20   b  protrude outward from the electrical junction box main body  12  with the bus bars  18  being installed in the main body  12 . The terminal section  20   a  is provided with two bolt through-holes  22   a  and  22   b  while the terminal section  20   b  is provided with a single bolt through-hole  22   c.    
         [0019]    On the other hand, the lower cover  14  is formed into a box-like configuration that is open upward. The lower cover  14  is provided on an outer periphery with two bolt receiving sections  24   a  and  24   b . The bolt receiving sections  24   a  and  24   b  are formed into substantially rectangular flat plate-like configurations and extend in a direction perpendicular to a height direction of the lower cover  14 . 
         [0020]    The one bolt receiving section  24   a  is provided with two bolt receiving apertures  26   a  and  26   b . A battery connecting bolt  28   a  and a starter connecting bolt  28   b  are inserted into the bolt receiving apertures  26   a  and  26   b  from a lower side of the bolt receiving section  24   a , respectively. 
         [0021]    The other bolt receiving section  24   b  is provided with a single bolt receiving aperture  26   c . An alternator connecting bolt  28   c  is inserted into the bolt receiving aperture  26   c  from a lower side of the bolt receiving section  24   b.    
         [0022]    The connecting bolts  28   a  to  28   c  are inserted into the bolt receiving apertures  26   a  to  26   c  with bolt covers  30  attached to heads of the bolts  28   a  to  28   c , which are prevented from being disconnected from bolt containing apertures  32  provided on lower parts of the bolt receiving sections  24   a  and  24   b . Under this condition, the connecting bolts  28   a  to  28   c  protrude from upper surfaces of the bolt receiving sections  24   a  and  24   b  so that the bolts  28   a  to  28   c  can slightly move in a vertical direction. 
         [0023]    The one bolt receiving section  24   a  is provided near the battery connecting bolt  28   a  with a battery cut-out portion  34   a  whose one end edge portion in a width direction is cut out. Also, the one bolt receiving section  24   a  is provided near the starter connecting bolt  28   b  with a starter cut-out portion  34   b  whose extending end side edge portion is cut out. 
         [0024]    The one bolt receiving section  24   a  is provided with a vertical wall  36   a  that extends along an end edge of the battery cut-out portion  34   a . The vertical wall  36   a  extend in parallel with a peripheral wall  38  of the lower cover  14  and is coupled to a vertical wall  36   b  that extends along one edge of the starter cut-out portion  34   b . A vertical wall  36   c  that extends along the other edge of the starter cut-out portion  34   b  extend in parallel with the vertical wall  36   b  and is coupled to the peripheral wall  38  of the lower cover  14 . Protruding end surfaces of the vertical walls  36   a  to  36   c  are disposed at the same level in height as a protruding end surface of the peripheral wall  38  of the lower cover  14  and shaft portions of the battery connecting bolt  28   a  and starter connecting bolt  28   b  protrude upward by a large amount. 
         [0025]    The other bolt receiving section  24   b  is provided near the alternator connecting bolt  28   c  with an alternator cut-out portion  34   c  whose protruding side end edge portion is cut out. 
         [0026]    The other bolt receiving section  24   b  is also provided with a vertical wall  40   a  that extends along one edge of the alternator cut-out portion  34   c , and with a vertical wall  40   b  that extends along the other edge of the alternator cut-out portion  34   c  and along the vertical wall  40   a . The vertical wall  40   a  is coupled to the peripheral wall  38  of the lower cover  14 , but the vertical wall  40   b  is not coupled to the peripheral wall  38  of the lower cover  14 . A clearance having a size sufficient to receive a fitting wall  44 , discussed below, is defined between the vertical wall  40   b  and the peripheral wall  38  of the lower cover  14 . 
         [0027]    Protruding end surfaces of the vertical walls  40   a  and  40   b  are disposed at the same level in height as a protruding end surface of the alternator connection bolt  28   c . The lower cover  14  is integrally provided on the peripheral wall  38  with a protruding wall  42  that protrudes upward and extends in a direction perpendicular to extending directions of the vertical walls  40   a  and  40   b . The protruding wall  42  is coupled to the vertical wall  40   a  and a protruding end surface of the wall  42  is disposed at the same level in height as the vertical walls  40   a  and  40   b . A dimension of the protruding wall  42  in a width direction (in right and left directions in  FIG. 1 ) is set to be slightly larger than a distance between the vertical walls  40   a  and  40   b.    
         [0028]    The lower cover  14  constructed above is incorporated in the electrical junction box main body  12  from the lower side. Under this condition, the terminal sections  20   a  and  20   b  of the bus bars  18  are superimposed on upper surfaces of the bolt receiving sections  24   a  and  24   b , and three connecting bolts  28   a  to  28   c  are inserted into three bolt through-holes  22   a  to  22   c , respectively. 
         [0029]    The fitting wall  44  (mentioned above) provided on the electrical junction box main body  12  is fitted into the clearance between the vertical wall  40   b  and the peripheral wall  38  of the lower cover  14 . A protruding end surface of the fitting wall  44  is disposed at the same level in height as protruding end surfaces of the vertical walls  40   a  and  40   b  and protruding wall  42 . Thus, the vertical walls  40   a , protruding wall  42 , fitting wall  44 , and vertical wall  40   b  form a substantially U-shaped configuration in cross section around the alternator connecting bolt  28   c  to surround the bolts  28   c  at three sides. The U-shaped configuration defines a coupling error check wall  46  having the same level in height as that of alternator connecting bolt  28   c.    
         [0030]    The coupling error check wall  46  is open at a side of the alternator cut-out portion  34   c  to surround the alternator connecting bolt  28   c  at three sides. Thus, when the feeder  48  to an alternator is disposed in the alternator cut-out portion  34   c , an electrical power supply terminal  50  provided on an end of the feeder  48  is mounted on the alternator connecting bolt  28   c . When a fixing nut  52  is screwed on and fastened to the alternator connecting bolt  28   c , the feeder  48  to the alternator is connected to the alternator connecting bolt  28   c.    
         [0031]    Because a clearance between the alternator connecting bolt  28   c  and the coupling error check wall  46  is set to be a suitable size, it is possible to prevent an alligator clip  54  for jump starter from being connected to the alternator connecting bolt  28   c . Specifically, by suitably adjusting a distance A between opposed surfaces of the vertical wall  40   a  and the fitting wall  44  in accordance with sizes of an electrical power supply terminal  50  and alternator connecting bolts  28   c , the alligator clip  54  for jump starter cannot enter the clearance between the opposed surfaces of the vertical wall  40   a  and the fitting wall  44 , when the alligator clip  54  for jump starter is opened so that it can clamp the alternator connecting bolt  28   c . As a result, it is possible to prevent the alligator clip  54  for jump starter from being connected to the alternator connecting bolt  28   c  so that the alligator clip  54  for jump starter clamps the alternator connecting bolt  28   c  in the opposed direction of the vertical wall  40   a  and fitting wall  44 . 
         [0032]    By suitably adjusting a clearance B between an outer periphery of the alternator connecting bolt  28   c  and the protruding wall  42  in a direction of a perpendicular extending down from a center of the alternator connecting bolt  28   c  to the protruding wall  42 , it is possible to prevent the alligator clip  54  for jump starter from being connected to the alternator connecting bolt  28   c  so that the alligator clip  54  for jump starter clamps the alternator connecting bolt  28   c  in the extruding direction of the vertical wall  40   a  and fitting wall  44 . The protruding wall  42  may protrude upward over a distal end of the alternator connecting bolt  28   c.    
         [0033]    A connecting terminal  58  is provided on an end of the feeder  56  connected to the battery and contained in the battery cut-out portion  34   a . After the connecting terminal  58  is mounted on the battery connecting bolt  28   a , a fixing nut  60  is screwed on and fastened to the battery connecting bolt  28   a . Thus, the feeder  56  from the battery is connected to the battery connecting bolt  28   a.    
         [0034]    The battery connecting bolt  28   a  protrudes over the protruding end surfaces of the vertical wall  36   a  and peripheral wall  38 . Thus, a space around the battery connecting bolt  28   a  is set to be larger than a space around the alternator connecting bolt  28   c . This permits the alligator clip  54  for jump starter to be connected to the battery connecting bolt  28   a.    
         [0035]    A connecting terminal  64  is provided on an end of the feeder  62  connected to the starter and contained in the starter cut-out portion  34   b . After the connecting terminal  64  is mounted on the starter connecting bolt  28   b , a fixing nut  66  is screwed on and fastened to the starter connecting bolt  28   b . Thus, the feeder  62  to the starter is connected to the starter connecting bolt  28   b . The alligator clip  54  for jump starter can be connected to the starter connecting bolt  28   b  that protrudes over the protruding end surfaces of the vertical wall  36   c  and peripheral wall  38 . 
         [0036]    In the electrical junction box  10  described above, the alligator clip  54  for jump starter is prevented from being connected to the alternator connecting bolt  28   c , but the clip  54  is permitted to be connected to the battery connecting bolt  28   a . As a result, it is possible to surely connect the alligator clip  54  for jump starter to the battery connecting bolt  28   a.    
         [0037]    Particularly, because the battery connecting bolt  28   a  and alternator connecting bolt  28   c  are plus (+) side terminal sections, they are disposed together at one place in order to enhance prevention of a short circuit due to contact with another member and to enhance efficiency of current conductive circuits in the electrical junction box  10 , in many cases. In this case, there may be a high risk that the alligator clip  54  for jump starter is coupled to the alternator connecting terminal  28   c  by mistake. Accordingly, the coupling error check wall  46  exerts its function effectively, thereby preventing the alligator clip  54  for jump starter from being coupled to the alternator connecting terminal  28   c.    
         [0038]    Because the protruding end surface of the coupling error check wall  46  is disposed at the substantially same level in height as that of the alternator connecting bolt  28   c , it is possible to effectively prevent the alligator clip  54  for jump starter from being coupled to the alternator connecting terminal  28   c.    
         [0039]    In addition, because the coupling error check wall  46  is formed by walls (vertical walls  40   a  and  40   b , protruding wall  42 , and fitting wall  44 ) integrated with the lower cover  14  and electrical junction box main body  12 , there is no increase in number of parts and it is possible to decrease the number of steps in production and lower the cost of production. 
         [0040]    Although exemplary embodiments of the present invention are described above, it should be noted that the present invention is not limited to the above embodiments. For example, only the vertical wall  40   a  and fitting wall  44  may constitute the coupling error check wall in the above embodiment. 
         [0041]    The protruding end surface of the coupling error check wall  46  may project over the protruding end surface of the alternator connecting bolt  28   c.