Abstract:
Disclosed is an electric junction box in which a pair of cassette blocks is arranged at intervals to each other in a component-attaching direction, capable of downsizing without increase of the number of component. The electric junction box comprises a pair of cassette blocks, configured to attach electric components thereto, arranged at intervals mutually in a component-attaching direction; and a cross-sectionally U-shaped bus bar attached to one cassette block, electrically connected to the electric components, a middle of the bus bar being arranged in a direction perpendicular to the component-attaching direction, both ends of the U-shaped bus bar being arranged in the component-attaching direction, wherein the electric components attached to the other cassette block are opposed to the middle of the bus bar.

Description:
This application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. JP2012-094486, filed Apr. 18, 2012, the entirety of which is incorporated by reference herein. 
     TECHNICAL FIELD 
     This invention relates to electric junction boxes employed for mutual connection with wire harnesses, particularly to electric junction boxes including a plurality of cassette blocks in which electric components are attached. 
     BACKGROUND ART 
     Various types of electric components are attached to automobiles. In order to supply power with, or transmit signals to these various types of electric components, the automobiles are provided with a plurality of wire harnesses that are wired therein, formed by bundling a plurality of electric wires. The automobiles are also provided with electric junction boxes that are placed at appropriate position employed for mutual connection of wire harnesses. 
     Known as one example for the above mentioned electric junction boxes is electric junction boxes including a pair of cassette blocks to which electric components are attached, and a case accommodating the pair of cassette blocks, and placed at intervals in a depth direction of the case (see PTL 1, for example). 
     CITATION LIST 
     Patent Literature 
     [PTL 1] 
     
         
         Japanese Patent Application Laid-Open Publication No. 2009-278800 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     Disadvantageously, in order to prevent interference between electric wires attached to one of the pair of cassette blocks and the electric components attached to the other of the pair of cassette blocks in the above mentioned electric junction boxes, it is necessary to broaden an interval of the pair of cassette blocks or to use a cover for keeping away the electric wires, posing drawbacks of upsizing of the case or increase of the number of the electric components. 
     Therefore, an object of the invention is to provide an electric junction block in which a pair of cassette blocks is arranged mutually at intervals in a component-attaching direction, allowing downsizing without increasing the number of components. 
     Solution to Problem 
     According to a first aspect of the invention to achieve the above mentioned object, an electric junction box comprises: a pair of cassette blocks configured to attach electric components thereto, arranged at intervals to each other in a component-attaching direction; and a cross-sectionally U-shaped bus bar attached to one of the pair of cassette blocks, electrically connected to the electric components, and including a middle portion and both ends, wherein the middle portion of the bus bar is arranged in a direction perpendicular to the component-attaching direction, and both ends of the bus bar are arranged in the component-attaching direction, and wherein the electric components attached to the other of the pair of cassette blocks are opposed to the middle of the bus bar. 
     Preferably, the electric components connected to the bus bar in the one of the pair of cassette blocks are arranged in two lines. 
     Preferably, the electric junction box includes a plate disposed in the one or the other of the pair of cassette blocks, wherein the plate extends toward the other or the one of the pair of cassette blocks, and is provided with an engaging part for being engaged by the other or the one of the pair of cassette blocks. 
     Preferably, the one of the pair of cassette blocks is configured to attach a fuse thereto, wherein the other of the pair of cassette blocks is configured to attach a relay thereto, and wherein the relay is connected in series to the fuse. 
     Advantageous Effects of Invention 
     According to the first aspect of the invention, since the electric components attached to the other of the pair of cassette blocks opposes the middle of the bus bar, and the electric wire attached to the one of the pair of cassette blocks and the electric components attached to the other of the pair of cassette blocks are not opposed in the component-attaching direction, it is made possible to narrow the interval between the pair of cassette blocks, and thus to provide the electric junction block that becomes downsized without increase of the number of components. 
     Furthermore, according to the invention, since the electric junction box includes the plate in the one or the other of the pair of cassette blocks, extending toward the other or the one of the pair of cassette blocks, and the plate is provided with an attaching part for being attached to the other or the one of the pair of cassette blocks, it is made possible to provide the electric junction block capable of being readily assembled. 
     Furthermore, since it is possible to position closely the fuse attached to the one of the pair of cassette blocks and the relay attached to the other the pair of cassette blocks, it is made possible to shorten electric wire connecting the relay and the fuse. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a cross-sectional view illustrating an electric junction box according to the first embodiment of the invention. 
         FIG. 2  is a perspective view illustrating a power source block illustrated in  FIG. 1 . 
         FIG. 3  is a front view illustrating the power source block illustrated in  FIG. 1 . 
         FIG. 4  is a plane view illustrating the power source block illustrated in  FIG. 1 . 
         FIG. 5  is a bottom view illustrating the power source block illustrated in  FIG. 1 . 
         FIG. 6  is an exploded view illustrating the power source block illustrated in  FIG. 1 . 
         FIG. 7  is a bottom view illustrating the first one of pair of cassette block composing the power source block illustrated in  FIG. 1 . 
         FIG. 8  is a perspective view illustrating the other of the first one of pair of cassette block composing the power source block illustrated in  FIG. 1 . 
         FIG. 9  is a schematic circuit diagram of the power source block illustrated in  FIG. 1 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     An electric junction box according to the invention is described with reference to  FIGS. 1 to 9 . 
     An electric junction box  1  of the present invention is such as is installed in an automobile, thus supplying power with, or transmitting signal to electric devices installed in the automobile. Hereinafter, a junction block (or referred to as junction box), a fuse block (or referred to as fuse box), or relay block (or referred to as relay box) is generically referred to as an electric junction box. 
     The above mentioned electric junction box is as shown in  FIG. 1  includes a power source block  10  composed of a pair of cassette blocks  3 ,  4 , and a case  2  accommodating the power source block  10 . The case  2  is composed of box-like case main body  2   a , a cover  2   b  covering an opening of the case main body  2   b.    
     The above mentioned power source block  10  as shown in  FIG. 9  supplies power, and is as shown in  FIGS. 2 to 6  composed of a plurality of electric components  6 ,  7 , and  8 , a pair of cassette blocks  3 ,  4  to which these electric components  6 ,  7 ,  8  are attached, a bus bar  5  attached to one cassette block  3 , and a plurality of electric wires  11 ,  12 . Reference sign  13  represents an input power line, reference sign  9  a connector connected to an end of the input power line  13 . 
     The above mentioned electric components  6 ,  7  are fuses, attached to the one of the pair of cassette blocks  3 . The above mentioned electric component  8  is a micro relay, attached to the other of the pair of cassette blocks  4 . An arrow Y in  FIGS. 1 to 6  represents a component-attaching direction in which the fuses  6 ,  7  and the micro relay  8  are attached to the cassette blocks  3 ,  4 , arrows X and Z perpendicular directions perpendicular to the component-attaching direction. 
     The above mentioned cassette block  3  is formed of synthetic resin. The cassette block  3  is provided with an oblong main body  30 , a connector engaging part  39  disposed at an end of the main body  30 , four latches  32 , and a pair of plates  31  disposed at both ends of the main body  30 . The main body  30  is provided with a plurality of fuse attached parts  36 ,  37  to which the plurality of fuses  6 ,  7  are attached. The plurality of fuse attached parts  36 ,  37  is, as shown in  FIG. 4 , arranged in two lines. The connector engaging part  39  has the above mentioned connector  9  engaged therein. The four latches  32  are each latched onto not-shown latched parts disposed in the case main body  2   a . The pair of plates  31  extends in a plate-like manner toward the other of the pair of cassette blocks  4 . Tip of each of the plates  31  is provided with an engaging part  34  in which the other of pair of cassette blocks  4  is engaged. 
     The above mentioned cassette block  4  is formed of synthetic resin. The other of pair of cassette blocks  4  is provided with an oblong main body  40 , and a pair of engagement receiving parts  43  disposed at both ends of the main body  40 . The main body  40  is provided with a plurality of relay attached parts  48  to which the plurality of micro relays  8  is attached. The plurality of relay attached parts  48  is arranged in series. The pair of engagement receiving parts  43  is engaged in the engaging part  34  disposed in the pair of plates  31  of the one of the pair of cassette blocks  3  above mentioned. 
     The engagement receiving parts  43  of the cassette block  4 , as shown in  FIG. 8 , is composed of a projection  43   a  projecting from an outer surface of the main body  40 , and a pair of rails  43   b  disposed at both sides of projection  43   a . The engaging part  34  of the cassette block  3  is as shown in  FIG. 6  composed of a projection  34   a  projecting from an inner surface of the plate  34   b , and a pair of grooves  34   b  disposed at both sides of the projection  34   a . The pair of rails  43   b  is inserted into the pair of grooves  34   b  and the projection  43   a  is engaged in the projection  34   a , the engagement receiving parts  43  and the engaging part  34  are thus engaged to each other. Accordingly, engagement of the engagement receiving parts  43  and the engaging part  34  allows the pair of cassette blocks  3 ,  4  to separate to each other at intervals in the component-attaching direction to be fixed. 
     The above mentioned bus bar  5  is, as shown in  FIG. 9 , intended for distributing power inputted from the connector  9  to the plurality of fuse  6 ,  7 , which is formed such as metal plate is pressed. This bus bar  5  is as shown in  FIG. 6 , provided with a base  50  bent into U-shape, a plurality of terminals  56 ,  57  extending from one end and the other end that oppose the base  50 , a terminal  59  connected to the connector  9 , and a connection part  51  connecting the terminal  59  and the base  50 . The terminal  56  is formed into tuning-fork-like shape, and electrically connected to the fuse  6 . The terminal  57  is formed into rectangular plate shape, electrically connected to the fuse  7 . 
     The above mentioned bus bar  5 , while attached to the cassette block  3  as shown in  FIG. 7 , has the middle of the base  50  thereof arranged in a perpendicular direction (the arrows X, Z) perpendicular to the component-attaching direction (the arrow Y), and has the plurality of terminals  56 ,  57  (U-shaped both ends) arranged in the component-attaching direction (the arrow Y). The middle  50   a  of the base  50  is formed into strip-like shape extending in the arrow X direction. The base  50  opposes the micro relay  8  attached to the cassette block  4  in the component-attaching direction (the arrow Y) (refer to  FIGS. 2 ,  3 ). 
     The above mentioned electric wire  11  as shown in  FIGS. 2 ,  5 , and  9 , is one that each connects the fuse  7  and the micro relay  8 . The electric wire  11  connected to each fuse  7  from bottom side of one of cassette block  3  also is passed at the side of the micro relay  8 , connected to each micro relay  8  from the bottom of the other cassette block  3 . Namely, the micro relay  8  is connected in series to the fuse  7  through the electric wire  11 . The above mentioned electric wire  12  is as shown in  FIGS. 2 ,  5 , and  9 , is one that is connected to each fuse  6 . The electric wire  12  connected to each fuse  6  from the bottom side of the one of cassette block  3  is passed the side of the micro relays  8 , and guided out of the case  2 . I.e., the electric wires  11 ,  12  do not oppose the micro relay  8  in the component-attaching direction. It follows from this that the electric wires  11 ,  12 , independently of dimension of interval between the pair of cassette blocks  3 ,  4 , avoid interfering with the micro relay  8 . 
     Thus, according to the invention the electric wire  12  attached to the one cassette block  3  avoids opposing the micro relay  8  in the component-attaching direction that is attached to the other cassette block  4 , allowing interval between the pair of cassette blocks  3 ,  4  to narrow as far as the bus bar  5  and the micro relay  8  avoid interfering with each other. Therefore it is made possible to downsizing the case  2 . Furthermore, there is not required a cover that keeps away the electric wire  12 . 
     Furthermore, since it is possible for the fuse  7  attached to the one cassette block  3  and the micro relay  8  attached to the other cassette block  4  to approach to each other, wiring work between the micro relay  8  and the fuse  7  is made easy. Furthermore, the electric wire connecting between the micro relay  8  and the fuse  7  is made short. 
     The above mentioned power source block  10  has the electric components  6 ,  7 ,  8 , and the electric wires  11 ,  12 , attached thereto, the pair of cassette blocks  3 ,  4  is, while attached to each other, inserted into the case main body  2   a , the four latches  32  disposed in the one cassette block  3  are each latched in the not-shown latched parts, and consequently the power source block  10  is installed into the case  2   a.    
     According to the invention, no need of installing each of the pair of cassette blocks  3 ,  4  into the case  2   a  allows the electric junction box  1  to be assembled easily. 
     Furthermore, as shown in  FIG. 1 , the cassette block  3  is arranged near an opening, and the cassette block  4  at the bottom side, of the case main body  2 . Such arrangement in the electric junction box  1  allows the fuse  6 ,  7  to be changed easily only by removing the cover  2   b  upon their being changed. 
     Furthermore, while in the above mentioned embodiment the one cassette block  3  has the pair of plates  31  disposed therein, in the present invention the other cassette block  4  may have the pair of plates  31  disposed therein. In addition, the pair of plates  31  is not necessarily disposed, but a latch means may in such case be disposed for attaching each the pair of cassette blocks  3 ,  4  to the case main body  2   a.    
     Note that the aforementioned embodiments merely show such as, but not limited to, typical embodiment of the present invention. Namely, it is to be understood that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention hereafter defined, they should be construed as being included therein. 
     REFERENCE SIGNS LIST 
     
         
           1  electric junction box 
           3 ,  4  cassette block 
           5  bus bar 
           6 ,  7  fuse (electric component) 
           8  micro relay (electric component)