Abstract:
An electrical connection box for a vehicle has bus bars providing upstanding tabs acting as terminals, and relay terminals fitted on the tabs. An insulation plate overlies the bus bars. A case member is assembled on the insulation plate by relative downward movement and provides housing spaces for the relay terminals. A partitioning wall separating adjacent housing spaces makes sliding contact with an upstanding wall of the insulation plate during assembly, and the partitioning wall and the upstanding wall in the assembled state at least partly surround a liquid-receiving space. The upstanding wall having an inclined upper end face. The construction minimizes risk of a current leak between the relay terminals.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates to an electrical connection box suitable for mounting on a vehicle, an industrial product such as a vehicle or robot, and more particularly an electrical connection box containing bus bars and relay terminals. 
     2. Description of Related Art 
     Electric and electronic parts for a vehicle are mounted in a vehicle body by accommodating them in or on an electrical connection box. JP-A-62-172219 shows an example of a known electrical connection box, which includes a circuit member comprising bus bars in layers, a plurality of relay terminals and a molded plastic material case. Upwardly projecting male tabs are formed by bending the bus bars and projecting them through the topmost insulating plate. The relay terminals are fitted on the male tabs. The case covers the relay terminals and has openings for terminals of a component which make contact with the relay terminals during use. In this type of arrangement there is a risk of water or other liquids penetrating into the case, leading to a possible leak current between the terminals. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide an electrical connection box capable of preventing or minimizing the risk of current leaks caused by the penetration of water or other liquids into the case. 
     According to one embodiment of the invention there is provided an electrical connection box having a plurality of bus bars providing at least two upstanding tabs acting as terminals, with relay terminals fitted on the tabs. An insulation plate overlies the bus bars and has respective apertures through which the tabs project. The electrical connection box has at least one upstanding wall located between the apertures and having an inclined upper end face. The insulation plate covers a case member and is assembled on the insulation plate by a downward movement relative to the insulation plate. Walls providing respective housing spaces for the relay terminals are included in the case member. The walls include a partitioning wall separating an adjacent pair of said housing spaces. 
     The partitioning wall is arranged to make sliding contact with the upstanding wall during the downward movement and the partitioning wall and the upstanding wall in the assembled state at least partly surround a liquid-receiving space. 
     In the construction of the invention, the upstanding wall of the insulation plate stands up between the pair of tab apertures, which are close to each other. When the insulating plate and the case member are combined with each other, the upstanding wall slidably contacts the partitioning wall separating the corresponding relay terminals. In this way a direct open path does not exist between the relay terminals. Therefore the respective housing spaces accommodating the relay terminals are separate from each other. In this case, even if water or other liquid penetrates into the housing spaces, it is possible to minimize risk of a current leak being generated between the relay terminals. Any path between the relay terminals is an elongate one, including the liquid-receiving space, in which water collects and can be drained to the exterior. 
     Further, the inclined face at the upper end of the upstanding wall is capable of restricting or controlling the flow direction of water, or the like which flows from above, along the partitioning wall. This may also help to prevent a current leak from being generated between the relay terminals. Preferably in the assembled state, the inclined upper end face of the upstanding wall slopes upwardly away from the partitioning wall. Preferably, the insulation plate has two such upstanding walls arranged alongside each other between the apertures, and the partitioning plate is slidably received between the two upstanding walls, the liquid-receiving space being located between the two upstanding walls below the partitioning wall. 
     It is also preferable that the upstanding wall has a step providing a horizontal surface, at least one of the relay terminals being located on this horizontal surface. The step having the horizontal surface perpendicular to the extension direction of the male tab is formed preferably in the vicinity of the base of the upstanding wall, adjacent to the tab aperture. The relay terminals are fitted on the male tabs respectively, with one or more of the relay terminals located on the horizontal surface of the step. Therefore the relay terminals are stably located, when fitted on the male tabs. Accordingly, it is possible to reduce the possibility of deformation of the male tabs and the relay terminals, and inaccurate location of the relay terminals. 
     Preferably the walls of the case member further include at least one outer side wall bounding the housing spaces. The outer side wall having an inclined inner face portion which slopes upwardly and inwardly with respect to the housing spaces. In this way, water or the like which flows from above along the inner surface of the outer side wall can be discharged easily to the outside. That is, water collection in the terminal housing space is minimized. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be described with reference to the accompanying drawings, in which like elements are labeled with like numbers and in which: 
     FIG. 1 is an exploded partial perspective view of an electrical connection box which is an embodiment of the present invention; 
     FIG. 2 is an enlarged perspective view on a part of the circuit member of the electrical connection box of FIG. 1; 
     FIG. 3 is a sectional view on line A—A of FIG. 1; 
     FIG. 4 is a sectional view corresponding to FIG. 3 when the circuit member and the case have been combined; and 
     FIG. 5 is a sectional view on line B—B of FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     An electrical connection box intended for use in a vehicle such as an automobile shown in FIGS. 1 to  5  has a circuit member  12 , a plurality of relay terminals  13  of punched and bent metal (only two are shown in FIG.  1 ), and a molded plastics material case  14 . The circuit member  12  is constructed of a plurality of layers of bus bars  15   a - 15   c  (three in this embodiment) formed of punched conductive sheet and a plurality of insulating plates  16   a - 16   d  (four in this embodiment) separating the layers of bus bars, with the topmost plate  16   a  covering the upper surface of the uppermost bus bar layer  15   a.    
     Male tabs  17   a - 17   d  are formed by bending up end portions of the bus bars  15   a - 15   c . The tabs  17   a - 17   d  extend upward through respective apertures, indicated as apertures  18   a  and  18   b  corresponding to the male tabs  17   a  and  17   d , in the topmost plate  16   a . The relay terminals  13  are fitted on the projecting male tabs  17   a - 17   d  and are formed to receive a male terminal at each end. The male tabs  17   a  and  17   b  and their apertures  18   a  and  18   b  are close to each other, and likewise the relay terminals  13   a  and  13   b  on the male tabs  17   a  and  17   b  are close to and confront each other. 
     On the topmost plate  16 a, which may be a molded plastics component, wall structures  21 - 24  extend upward around the periphery of each aperture receiving a male tab  17   a - 17   d . The wall structures  21  and  22  partially receive the relay terminals  13   a  and  13   b  respectively. The wall structure  21  has opposite end walls  21   c , a side wall  21   b  remote from the wall structure  22  and a side wall  21   a  adjacent the wall structure  22 . The wall structure  22  has opposite end walls  21   c , a side wall  22   a  adjacent the wall structure  21  and of the same height as all the walls  21   a ,  21   b  and  21   c  thereof and a lower side wall  22   b  at its side remote from the wall structure  21 . When the relay terminals  13   a  and  13   b  are fitted on the male tabs  17   a  and  17   b  they are held by the wall structures  21  and  22 , as seen in FIGS. 3 to  5 . Preferably the relay terminals  13   a  and  13   b  are received by the wall structures  21  and  22  for about ¼ to ⅓ of their height. 
     As shown in FIG. 3, the distance Cl between the side wall  21   a  and the side wall  22   a  is almost equal to a thickness C 2  of a partition wall  34   a  of the case  14 . A-sloping surface  25  (sloping downwardly away from the relay terminal  13   a ) is formed at the upper end of each of the side walls  21   a  and  22   a . A sloping surface  26  (sloping downwardly away from the relay terminal  13   a ) is formed on the side wall  21   b . A step  27  having a horizontal surface perpendicular to the direction of the male tab portions  17   a  and  17   b  is formed in the vicinity of the base of each of the wall structures  21  and  22  extending continuously around the apertures  18 a and  18 b. The lower ends of the relay terminals  13   a  and  13   b  fitted on the male tabs  17   a  and  17   b  are located on the horizontal surfaces of the steps  27 . Sloping surfaces  28  (sloping downwardly away from the male tabs  17   c ) are formed at the upper ends of the wall structures  24 . 
     As shown in FIG. 1, an installing zone  31  for an electrical or electronic component is provided at the outer side of the case  14  having through-holes  31   a  at positions corresponding to the male tabs  17   a - 17   d  respectively. As shown in FIG. 3, at the inside of the case  14 , a terminal housing  32  has an outer side wall  33  surrounding all the relay terminals  13  and partition walls  34  separating the relay terminals  13  from each other. Thereby a plurality of compartments or accommodation spaces  35  are formed in the terminal housing  32 . When the circuit member  12  and the case  14  are combined with each other, the spaces  35  accommodate the relay terminals  13  separately. 
     An outwardly inclined surface  36  is formed in the vicinity of the lower end of the inner surface of the outer side wall  33  of the terminal housing  32 . The inclined surface  36  is in correspondence to the sloping surface  26  formed of the wall  21   b  and the sloping surfaces  28  and  29  of the wall structures  23  and  24 . As shown in FIG. 4, when the circuit member  12  and the case  14  are combined with each other, the inclined surface  36  contacts the inclined surfaces  26 ,  28  and  29 . In FIG. 4, to make the construction of the components of the case  14  clear, a slight gap is shown between the inclined surface  36  and the inclined surfaces  26 ,  28  and  29 . 
     The partition wall  34   a  separating the spaces  35   a  and  35   b  accommodating the adjacent relay terminals  13   a  and  13   b  tapers toward its lower end. As shown in FIG. 4, when the circuit member  12  and the case  14  are combined, the partition wall  34   a  is inserted between the side walls  21   a  and  22   a , slidably contacting the outer surface of the side walls  21   a  and  22   a . The length of the partition wall  34   a  is such that a predetermined space  37  is formed surrounded by the side walls  21   a ,  22   a  and the partition wall  34   a . In FIG. 4, to illustrate the construction more clearly, a slight gap is shown between the partition wall  34   a  and the side walls  21   a  and  22   a.    
     When the circuit member  12  and the case  14  are united with each other, a component  38  (a relay in this embodiment) is mounted on the zone  31  with its connection terminals  38   a  inserted into the corresponding through-holes  31   a . The connection terminals  38   a  are fitted in the respective relay terminals  13  to connect the relay  38  and the male tabs  17   a - 17   d  electrically. In use the electrical connection box  11  is mounted in a vehicle compartment, with the case  14  combined with a lower case (not shown) to mount and enclose the circuit member  12 . 
     In the embodiment described above, effects such as the following are obtained. 
     (1) The walls  21 - 24  project up around the periphery of each aperture of the uppermost insulating plate  16   a . When the circuit member  12  and the case  14  are combined, the side walls  21   a  and  22   a  slidably contact the side surfaces of the partition wall  34   a , so that the spaces  35   a  and  35   b  accommodating the relay terminals  13   a  and  13   b  respectively are well separated from each other. Thereby, even if water penetrates into the terminal housing, the risk of a leak current between the relay terminals  13   a  and  13   b  is minimized. The walls  21  and  22  surround the relay terminals  13   a  and  13   b  over the lower part of their height, providing an elongated surface path between the relay terminals  13   a  and  13   b . This helps to prevent a current leak between the relay terminals  13   a  and  13   b.    
     The inclined surfaces  25  at the upper ends of the side walls  21   a  and  22   a  slope towards the partition wall  34 , so that water flowing from above down the partition wall  34   a  flows easily into the space  37  and not into the circuit member  12 . This helps prevent the generation of current leaks in the circuit member  12 . It is simple to provide a construction for discharging water which has passed into the space  37  to the outside of the circuit member  12 . The collection of water in the space  37  also helps to prevent a current leak from being generated between the relay terminals  13   a  and  13   b.    
     In recent years, as increasing numbers of electric and electronic parts are mounted on a vehicle body, the tendency is to adopt a battery voltage of 42V. Thus, prevention of the generation of current leaks has become more important. 
     (2) The steps  27  having a horizontal upper surface perpendicular to the direction of the male tabs  17   a  and  17   b  are formed in the vicinity of the base of the wall structures  21  and  22  around the apertures  18   a  and  18   b  and locate the ends of the relay terminals  13   a  and  13   b . Thereby the relay terminals  13   a  and  13   b  are stably positioned, making it possible to prevent deformation of the male tabs  17   a  and  17   b  and the relay terminals  13   a  and  13   b . Inaccuracy in location of the relay terminals  13   a  and  13   b  is also prevented. Further, by appropriately choosing the height of the horizontal surface of the steps  27 , it is possible to freely select the height location of the relay terminals  13   a  and  13   b . Thus it is possible to make the height positions of the relay terminals  13   a  and  13   b  uniform, even if the relay terminals  13  to be mounted on the male tabs  17   a - 17   d  are of different types and even if the height dimensions of the relay terminals  13  are different. 
     (3) Since the inclined surface  36  in the vicinity of lower end of the inner surface of the outer side wall  33  of the terminal housing  32  widens downwardly, water flow from above on the inner surface of the side wall  33  can be discharged easily to the outside. Water is therefore not likely to collect in the terminal housing  32 . This reduces the risk of current leakage. 
     The partition wall  34   a  is thinner toward its lower end, so that when the circuit member  12  and the case  14  are joined, the partition wall  34   a  can be easily inserted into the space between the side walls  21   a  and  22   a.    
     Some possible modifications of the illustrated embodiment of the present invention are as follows: 
     In the illustrated embodiment, the inclined surfaces  25  slope upwardly gradually away from the partition wall  34   a , but the surfaces  25  may be formed in such a way that they gradually converge towards the partition wall  34   a  toward their upper ends. This construction allows water, which flows from above along the partition wall  34   a , to easily pass to the aperture  18  along the surfaces  25 . That is, it is difficult for the water to penetrate into the gap between the partition wall  34   a  and the side walls  21   a  and  22   a . Thereby it is possible to prevent a current leak between the relay terminals  13   a  and  13   b.    
     An inclined surface like the inclined surface  26  may be formed on the tops of the side walls  21   c  of the wall structure  21  and the side walls  22   c  of the wall structure  22 . 
     It is possible to omit the formation of the steps  27  in the vicinity of the base of the wall structures  21  and  22  in order to simplify the construction of the insulating partitioning plate  16   a.    
     It is possible to omit the formation of the inclined surface  36  on the outer side wall  33 . Further, the partition wall  34   a  may be formed with the same thickness at its upper and lower ends. 
     In the illustrated embodiment, the side walls  21   a  and  21   b  are formed to the same height, but the side wall  21   b  may be formed lower than the side wall  21   a . Even if water may collect in the portion surrounded by the wall  21 , it is discharged to the outside from the gap between the side wall  21   b  and the outer side wall  33 . Therefore, the water level does not become higher than the side wall  21   b . In this case, it is possible to reduce the possibility that water passes between the side wall  21   a  and the partition wall  34   a . This helps to prevent a current leak between the relay terminals  13   a  and  13   b.    
     In the illustrated embodiment, when the circuit member  12  and the case  14  are combined, the inclined surface  36  of the outer side wall  33  contacts the inclined surfaces  26 ,  28  and  29 . But it is possible to form a gap between the inclined surface  36  and each of the surfaces  26 ,  28  and  29  in the assembled state. This construction also allows water or the like to be discharged effectively to the outside via the gaps. 
     In one embodiment, the wall structures  21  and  22  are formed to accommodate ¼-⅓ of the height of relay terminals  13   a  and  13   b  respectively, but this height overlap is not limited to this range. 
     The wall structures  21  and  22  may be constructed of only the side walls  21   a  and  22   a  close to each other. That is, the wall structures  21  and  22  may be provided only between two closely adjacent apertures  18 . 
     The electrical connection box  11  may be used for an industrial robot or the like, other industrial product, as well as on a vehicle. 
     While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention.