Patent Publication Number: US-6707689-B2

Title: Junction box

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 2001-326153, filed Oct. 24, 2001; and No. 2001-326154, filed Oct. 24, 2001, the entire contents of both of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a junction box including connecting terminals for electrically connecting a connector, fuse, and the like to a wiring circuit, and particularly to a junction box which is lightweight and thin, can freely change connection positions with outer wiring circuits such as a harness and can enhance a wiring design freedom degree. 
     2. Description of the Related Art 
     In general, to branch a wiring of a car or the like, a junction box (J/B) has been used for purposes of space saving and cost reduction. FIG. 14 is a plan view of the junction box, FIG. 15 is a plan view of a bus bar contained in the junction box, FIG. 16 is a sectional view of a part VII of FIG. 14, and FIG. 17 is a sectional view of a part VIII of FIG.  14 . 
     This type of a junction box  101  is constituted of a lower cover  102 , a bus bar  103  attached to the lower cover  102 , and an upper cover  105  which seals the lower cover and bus bar and to which a connector, fuse, and the like are attached. In the junction box  101 , as shown in FIG. 15, the bus bar  103  formed, for example, of a pressed/punched metal plate of copper alloy, aluminum alloy, or the like is used to branch the wiring. Moreover, the junction box  101  also includes a function, for example, of a fuse box, when a fuse  107  is incorporated halfway in the wiring circuit constituted by the bus bar  103 . 
     A connector  107  shown in FIG. 16 is a connector connected to the wiring circuit constituted of the bus bar  103 . A connector  105   a  can be connected to the connector  107 , when a connecting terminal portion  103   a  formed by bending a tip end of the bus bar  103  upwards by 90° is passed upwards through an upper cover  105  via a through hole  105   b  formed in the cover. Moreover, for a fuse attachment portion  105   c  to which a fuse  108  is attached as shown in FIG. 17, a connecting terminal portion  103   d  is formed by bending the tip end of the bus bar  103  with a slit  103   b  formed therein upwards by 90°, and is passed upwards through the upper cover  105  through a through hole  105   d  formed in the cover. Thereby, the connecting terminal portion can directly be connected to a leg  108   a  for connecting the fuse  108 , or can be connected using a so-called female to female (F—F) terminal. 
     Moreover, as shown in FIG. 18, the bus bars  103  and insulation plates (IP)  109  having functions of supporting and insulating the bus bars  103  are alternately superimposed to form a wiring circuit (multilayered wiring circuit)  110  which has a multilayered structure. A junction box  112  structured to contain the multilayered wiring circuit  110  in a housing for entirely protecting the outside of the circuit as shown in FIG. 19 is frequently used. 
     However, in the above-described junction box  101 , the bus bar  103  is manufactured by punching the metal plate with a die and the wiring circuit is formed. Therefore, when the bus bars  103  having various shapes are manufactured, different dies are required, and much cost is taken. Moreover, the bus bar  103  is formed of a thick metal, a weight of the junction box  101  therefore increases, and there is a problem that it is difficult to thin the junction box  101 . Furthermore, in the junction box  112 , the number of layers of the multilayered wiring circuit  110  needs to be minimized in order to prevent the weight and cost of the entire junction box from increasing. Additionally, the multilayered wiring circuit  110  having a small number of layers is used in accordance with a connection mode. For this, a circuit is drawn so as to avoid a wiring circuit of another layer and through holes  111  through which the connecting terminal portions  103   a ,  103   d  are passed, and a long circuit needs to be formed. This causes a problem that it is very difficult to lighten and thin the junction box  112 . 
     Furthermore, when the bus bar  103  is used to form a multilayered wiring circuit having more layers, for example, the type of the bus bar  103  increases, and the cost of a metal mold increases. Therefore, it is difficult to realize a high-density wiring. As a result, a problem occurs that a freedom degree of wiring design of the junction box is restricted. 
     BRIEF SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a junction box in which weight saving and thinning are realized and a freedom degree of wiring design can be enhanced. 
     According to an aspect of the present invention, the object is achieved by providing a junction box comprising: a junction box main body to which an electric component to be connected is attached; a connector portion which connects a connector of an outer wiring circuit and a joint connector of a circuit distribution wiring circuit and is formed separately from the junction box main body; and a cable portion which is constituted of a flexible printed circuit with a circuit portion including a conductor pattern formed on an insulating film, and electrically connects the junction box main body to the connector portion, wherein the flexible printed circuit includes: a strip portion which connects the junction box main body to the connector portion; and a terminal connecting portion extending from a side edge of a position of the strip portion in which the junction box main body and connector portion are arranged in a short direction of the strip portion, 
     the junction box main body includes: a junction box housing including a component attachment port to which the electric component to be connected is attached; and a plate-shaped first connecting terminal which is connected to the terminal connecting portion of the flexible printed circuit and contained in the junction box housing so as to be connected to the electric component to be connected, and the connector portion includes: a connector housing which is engaged with at least one of the connector of the outer wiring circuit and the joint connector of the circuit distribution wiring circuit; a plate-shaped second connecting terminal which is connected to the terminal connecting portion of the flexible printed circuit and contained in the connector housing so as to be connected to the connector of the outer wiring circuit; and a plate-shaped third connecting terminal which is connected to the terminal connecting portion of the flexible printed circuit and contained in the connector housing so as to be connected to the joint connector of the circuit distribution wiring circuit. 
     Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention. 
     FIG. 1 is a perspective view showing an appearance of a junction box according to one embodiment of the present invention; 
     FIG. 2 is an exploded perspective view showing a constitution of a cable portion; 
     FIGS. 3A and 3B are a top plan view and sectional view of an FPC constituting a part of a cable portion; 
     FIGS. 4A and 4B are top plan views of the FPC constituting the part of the cable portion; 
     FIG. 5 is a partially sectional view showing that a first connecting terminal is attached to a junction box housing; 
     FIG. 6 is a partially sectional view showing that second and third connecting terminals are attached to a connector housing; 
     FIG. 7 is a sectional view as viewed from an arrow A of FIG. 6; 
     FIG. 8 is a perspective view showing the appearance of the junction box according to another embodiment of the present invention; 
     FIG. 9 is an exploded perspective view showing the constitution of the cable portion; 
     FIGS. 10A and 10B are a top plan view and sectional view of the FPC constituting a part of the cable portion; 
     FIG. 11 is a partially sectional view of a connecting portion between circuits; 
     FIGS. 12A and 12B are top plan views of the FPC constituting a part of a cable; 
     FIGS. 13A and 13B are partially sectional views showing that the second connecting terminal is attached to the connector housing; 
     FIG. 14 is a plan view of a conventional junction box; 
     FIG. 15 is a plan view of a bus bar contained in the junction box; 
     FIG. 16 is a sectional view of a part VII of FIG. 14; 
     FIG. 17 is a sectional view of a part VIII of FIG. 14; 
     FIG. 18 is an upward perspective view showing a conventional wiring circuit having a multilayered structure; and 
     FIG. 19 is an upward perspective view showing the junction box in which the conventional wiring circuit having the multilayered structure is contained. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Embodiments of the present invention will be described hereinafter with reference to the accompanying drawings. 
     FIG. 1 is a perspective view showing an appearance of a junction box according to one embodiment of the present invention. 
     A junction box  1  is constituted of a junction box main body  10 , first connector portion  20   a , second connector portion  20   b , and cable portion  30  for connecting the junction box main body  10  to the connector portions  20   a ,  20   b . The cable portion  30  is formed by freely laminating a plurality of strip-shaped flexible printed circuits (hereinafter abbreviated as “FPC”)  30   a  to  30   d  in a non-bonded state. On the other hand, the junction box main body  10  includes a junction box housing  13  formed of a resin molded member and a lid body  16  which is attachable/detachable with respect to the junction box housing  13 , and is disposed on one end of the cable portion  30 . In the junction box housing  13 , in surfaces corresponding to front and rear surfaces) disposed opposite to side edges of the FPCs  30   a  to  30   d , a plurality of fuse attachment portions  14  and relay attachment portion  15  for attaching a plurality of fuses  11  and relay  12  are formed in one row along a longitudinal direction of the cable portion  30 . 
     First and second connectors  22   a ,  22   b  include connector housings  22   a ,  22   b  formed of resin molded members, and case portions  23   a ,  23   b  in which the connector housings  22   a ,  22   b  are partially contained and which can be divided in a thickness direction of the cable portion  30 . The connectors are arranged in the other end of the cable portion  30 . The connector housings  22   a ,  22   b  include a plurality of connector engagement portions  25  which are arranged in the surfaces disposed opposite to the side edges of the FPCs  30   a  to  30   d  along opposite side edges of the cable portion  30 , and into which a plug connector  21  and joint connector  29  of the circuit distribution wiring circuit are inserted. 
     FIG. 2 is an exploded perspective view showing a constitution of the cable portion  30 . Additionally, the cable portion  30  may also be constituted of one FPC, but in this example a plurality of FPCs superimposed upon one another in the non-bonded state will be described. 
     First, each of the strip-shaped FPCs  30   a ,  30   b ,  30   c ,  30   d  constituting the cable portion  30  is constituted by disposing a circuit portion  32  formed by patterning a conductor material such as a copper foil on a base film  31  of an insulating film such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN) and polyimide (PI). If necessary, a cover layer (not shown) is added onto this structure. 
     A plurality of terminal connecting portions  34  are formed so as to extend from the opposite side edges of a strip portion  33  of each of the FPCs  30   a  to  30   d  by predetermined lengths in a short direction of the strip portion  33 . Each tip end of these terminal connecting portions  34  is connected to: a first connecting terminal  39   a  which is contained in the junction box housing  13 , constitutes a part of the junction box main body  10 , and has a metal plate shape; and second and third connecting terminals  39   b ,  39   c  which are contained in the connector housing  22   a  ( 22   b ), and constitute a part of the connector portion  20 . Additionally, in this example, the first connecting terminal  39   a  is a so-called fork terminal connected to the fuses  11  and relay  12 , and the second and third connecting terminals  39   b ,  39   c  are so-called male connecting terminal connected to a female connecting terminal (not shown) of the plug connector  21 , or a connecting terminal connecting portion (not shown) of the joint connector  29 . Moreover, the terminal connecting portions  34  may also be formed only on one side edge of the strip portion  33 . In this case, the connector of the outer wiring circuit, plug connector  21  and joint connector  29  are arranged on the surface of the terminal connecting portion disposed opposite to the side edge of the cable portion  30  on the same side. Moreover, as in the second and third connecting terminals  39   b ,  39   c  of this example, the second and third connecting terminals  39   b ,  39   c  may be formed in the same shape. 
     In this example, the first connecting terminals  39   a  are connected to the terminal connecting portions  34  formed on opposite side edges of the strip portion  33 . The second connecting terminals  39   b  are connected to the terminal connecting portions  34  formed on one side edge of the strip portion  33 , and the third connecting terminals  39   c  are connected to the terminal connecting portions  34  formed on the other side edge. Additionally, in the first, second and third connecting terminals  39   a  to  39   c , engagement holes  39   d  engaged with a lance mechanism disposed in the junction box housing  13  or the connector housing  22   a  ( 22   b ) as described later are formed. However, the holes may not be formed, when the connecting terminals are not locked/fixed by the lance mechanism. 
     FIGS. 3A and 3B show a top plan view and sectional view of the FPC  30   a  constituting a part of the cable portion  30 . As shown in FIG. 3B, the first to third connecting terminals  39   a  to  39   c  are laid on the terminal connecting portions  34  so as to adhere to the circuit portion  32  on the terminal connecting portions  34 , subsequently subjected, for example, to resistance welding (series welding) by a pair of electrodes  38   a ,  38   b  of a series welding apparatus (not shown) allowed to abut from above a bonded portion with the circuit portion  32 , bonded to the circuit portion  32  and connected to the terminal connecting portions  34 . Additionally, since the resistance welding is a known technique, the description thereof is omitted. Additionally, the connecting terminals  39   a  to  39   c  may also be connected to the terminal connecting portions  34  by other methods such as ultrasonic welding, laser welding and soldering. When the terminals are connected to the portions in these connection methods, a high connection reliability can be secured. 
     After the first to third connecting terminals  39   a  to  39   c  are connected to the terminal connecting portions  34 , the FPCs  30   a  to  30   d  are superimposed upon one another and the cable portion  30  is constituted. In this case, the terminal connecting portions  34  of the respective FPCs  30   a  to  30   d  are formed so that the first to third connecting terminals  39   a  to  39   c  are arranged in positions corresponding to connecting terminal arrangement positions of the junction box housing  13  and connector housing  22   a  ( 22   b ). After the strip FPCs  30   a  to  30   d  are superimposed upon one another to form the cable portion  30  in this manner, for example, a bonded portion of the connecting terminal  39   a  ( 39   b ,  39   c ) to the terminal connecting portion  34  is sealed by a resin molded portion  37  as shown in FIG.  2 . Then, connection reliability of the bonded portion can be enhanced. Moreover, the terminal connecting portions  34  connected to the first to third connecting terminals  39   a  to  39   c  are arranged as such. The first connecting terminals  39   a  are attached to the junction box housing  13  and the second and third connecting terminals  39   b ,  39   c  are attached to the connector housing  22   a  ( 22   b ) so that the terminals are arranged in predetermined terminal arrangement positions. 
     Here, the circuit portion  32  is formed by a so-called solid pattern in the above-described FPC  30   a . However, for example, when the circuit portion  32  is formed of a plurality of conductor patterns as shown in FIGS. 4A and 4B, a plurality of wiring circuits can be constituted on each of the FPCs  30   a  to  30   d . Additionally, in the following description, the description of the FPCs  30   a  and  30   d  is omitted, and only the FPCs  30   b  and  30   c  will be described. Contents described hereinafter can be applied to all the FPCs  30   a  to  30   d  constituting the cable portion  30 . 
     As shown in FIGS. 4A and 4B, when the circuit portion  32  is formed so as to include a plurality of conductor patterns, it is possible to construct a plurality of wiring circuits on one FPC  30   b  ( 30   c ). As a result, the number of FPCs laminated in the non-bonded state can be decreased, and the thinning and weight saving of the cable portion  30  can be promoted. 
     FIG. 5 is a partially sectional view showing that the first connecting terminals  39   a  are attached to the junction box housing  13  of the junction box main body  10 , and FIG. 6 is a partially sectional view showing that the second and third connecting terminals  39   b ,  39   c  are attached to the connector housing  22   a  ( 22   b ) of the connector portion  20   a  ( 20   b ). 
     As shown in FIG. 5, in predetermined positions of a junction box housing  13   a  ( 13   b ) of the junction box main body  10 , there are formed: terminal containing holes  24   a  through which the first connecting terminals  39   a  are passed and in which the tip ends of the terminals are contained in an exposed state; and lance portions  26   a  as a lance mechanism, which are engaged with the engagement holes  39   d  of the first connecting terminals  39   a  and lock/fix the first connecting terminals  39   a  in both the junction box housings  13   a ,  13   b . The junction box housings  13   a ,  13   b  are locked by a lock mechanism (not shown), and structured such that the housings can vertically be divided by unlocking the mechanism. The FPCs  30   b ,  30   c  constituting the cable portion  30  are contained in the junction box housings  13   a ,  13   b  while circuit formed surfaces of the circuit portions  32  are longitudinally disposed and the terminal connecting portions  34  are extended as such from the opposite side edges. 
     On the other hand, as shown in FIG. 6, in the connector housings  22   a ,  22   b , there are formed: the connector engagement portions  25  which are engaged with the connector of the outer wiring circuit, plug connector  21  and joint connector  29 ; a plurality of terminal containing holes  24   b  through which the second and third connecting terminals  39   b ,  39   c  are passed and in which the terminals having the tip ends of the terminals projected in the connector engagement portion  25  are contained; and an insertion hole  27  into which the cable portion  30  having the connecting terminals  39   b ,  39   c  passed through the terminal containing holes  24   b  is inserted in the side edge direction of the strip portion  33 . In a plurality of terminal containing holes  24   b , the lance portions  26   b  as the lance mechanism, which are engaged with the engagement holes  39   d  of the connecting terminals  39   b ,  39   c  and lock/fix the connecting terminals  39   b ,  39   c  in the connector housings  22   a ,  22   b  are formed. The terminal connecting portions  34  of the FPCs  30   b ,  30   c  constituting the cable portion  30  are contained in the insertion holes  27  in the connector housings  22   a ,  22   b  so that the terminal connecting portions constitute the predetermined connecting terminal arrangement positions in a state shown in FIG.  6 . 
     In this example, the joint connector  29  including a circuit distribution wiring circuit  50  is engaged in the connector engagement portion  25  of the connector housing  22   b  in which the third connecting terminals  39   c  are contained. Moreover, the third connecting terminals  39   c  in the predetermined positions are connected to a connecting terminal connecting portion  51  disposed in a terminal portion of the circuit distribution wiring circuit  50 . As shown in FIG. 7, the circuit distribution wiring circuit  50  of this example is designed to include a bus bar structure formed by punching/processing a predetermined metal plate and subsequently bending/processing the plate. The connecting terminal connecting portion  51  is formed in the terminal portion by the above-described processing method, and the circuit is designed so as to cause a short circuit in the circuit portions  32  which achieve electric conduction of the FPCs  30   b ,  30   c . Additionally, a circuit distribution wiring circuit including the connecting terminal in the FPC or a circuit distribution wiring circuit formed of a general copper wire can also be applied. The circuit distribution wiring circuit  50  of this example may also be formed so that electricity is conducted among a plurality of circuit portions  32  formed on the same FPC in a predetermined circuit mode, or so that electricity is conducted among a plurality of circuit portions  32  formed on a plurality of FPCs in the predetermined circuit mode. Moreover, the circuit may also be formed so as to realize both modes at the same time. 
     Since electricity is conducted through the desired circuit portions  32  on the FPCs  30   b ,  30   c  by the circuit distribution wiring circuit  50  of the joint connector  29 , a so-called interlayer connection between both the FPCs  30   b ,  30   c  or the wiring circuit formed over the junction box main body  10  and connector portion  20  can freely be changed. For example, as shown in FIG. 4, a third connecting terminal  39   c   1  of the FPC  30   b  is connected to a third connecting terminal  39   c   1 ′ of the FPC  30   c  by the circuit distribution wiring circuit  50  of the joint connector  29 . In this case, a second connecting terminal  39   b   1  of the FPC  30   b  is electrically connected to a second connecting terminal  39   b   2  of the FPC  30   c . Therefore, a circuit portion  32   a  of the FPC  30   b  and a circuit portion  32   b  of the FPC  30   c  can constitute one circuit. 
     On the other hand, for example, when a third connecting terminal  39   c   2  of the FPC  30   b  is connected to a third connecting terminal  39   c   2 ′ of the FPC  30   c , the second connecting terminal  39   b   1  of the FPC  30   b  is electrically connected to a first connecting terminal  39   a   1  of the FPC  30   c . Therefore, the circuit portion  32   a  of the FPC  30   b  and a circuit portion  32   c  of the FPC  30   c  can constitute one circuit. In this manner, the connection mode of the circuit portion  32  can be changed to a desired mode by the circuit distribution wiring circuit  50  of the joint connector  29 . Therefore, for example, when interlayer connection is performed, many circuit portions  32  are formed on one FPC  30   b  ( 30   c ) and this high-density wiring is possible. Moreover, this decreases the number of layers and can promote weight saving. Furthermore, when the connection mode of the circuit portion  32  by the circuit distribution wiring circuit  50  is changed in accordance with various uses, a design of circuit can easily be changed, and a circuit application range can be broadened. Thereby, it can be expected that a freedom degree of wiring design of the junction box is rapidly enhanced. 
     FIG. 8 is a perspective view showing the appearance of the junction box according to another embodiment of the present invention. Additionally, duplicate description of the already described portions is omitted hereinafter. 
     The junction box  1  is constituted of the junction box main body  10 , first connector portion  20   a , second connector portion  20   b , and cable portion  30  for connecting the junction box main body  10  to the connector portions  20   a ,  20   b . The cable portion  30  is formed by laminating a plurality of strip-shaped FPCs  30   a  to  30   d  in the non-bonded state and bendable manner. The junction box main body  10  includes the junction box housing  13  and the lid body  16  which is attachable/detachable with respect to the junction box housing  13 , and is disposed on one end of the cable portion  30 . In the surfaces of the junction box housing  13  disposed opposite to the side edges of the FPCs  30   a  to  30   d , a plurality of fuse attachment portions  14  and relay attachment portion  15  for attaching a plurality of fuses  11  and relay  12  are formed in one row along the longitudinal direction of the cable portion  30 . 
     The first and second connector portions  20   a ,  20   b  include the connector housings  22   a ,  22   b , and case portions  23   a ,  23   b  in which the connector housings  22   a ,  22   b  are partially contained and which can be divided in a thickness direction of the cable portion  30 . The connector portions are arranged in the other end of the cable portion  30 . In this example, the connector housings  22   a ,  22   b  include a plurality of connector engagement portions  25  which are arranged on the surfaces disposed opposite to the side edges of the FPCs  30   a  to  30   d  along one side edge of the cable portion  30 , and into which the connector of the outer wiring circuit (not shown) and plug connector  21  are inserted. 
     FIG. 9 is an exploded perspective view showing the constitution of the cable portion  30 . 
     First, each of the strip FPCs  30   a ,  30   b ,  30   c ,  30   d  constituting the cable portion  30  is constituted by disposing the circuit portion  32  formed by patterning the conductor material such as the copper foil on the base film  31  of the insulating film such as PET, PEN and PI. If necessary, the cover layer (not shown) is added onto this structure. 
     A plurality of terminal connecting portions  34  are formed so as to extend from opposite side edges of the strip portion  33  of each of the FPCs  30   a  to  30   d  by predetermined lengths in the short direction of the strip portion  33 . Each tip end of these terminal connecting portions  34  is connected to: the first connecting terminals  39   a  which are contained in the junction box housing  13 , constitute a part of the junction box main body  10 , and have a metal plate shape; and second connecting terminals  39   b  which are contained in the connector housing  22   a  ( 22   b ) and constitute a part of the connector portion  20 . Moreover, a plurality of circuit connecting portions  35  are formed to extend from one side edge of the strip portion  33  of each of the FPCs  30   a  to  30   d  by predetermined lengths in the short direction of the strip portion  33 , so that the circuit portion  32  of an extending direction tip end is in an exposed state. Additionally, in this example, the first connecting terminal  39   a  is a so-called fork terminal which is connected to the fuses  11  or the relay  12 . The second connecting terminal  39   b  is a so-called male connecting terminal connected to each female connecting terminal (not shown) of the connector of the outer wiring circuit or the plug connector  21 . Moreover, the terminal connecting portions  34  may also be formed only on one side edge of the strip portion  33  as in the junction box  1  of this example. In this case, the connector of the outer wiring circuit or the plug connector  21  is disposed in the surface disposed opposite to the side edge of the cable portion  30  on the same side as shown in FIG.  8 . 
     In this example, the first connecting terminals  39   a  are connected to the terminal connecting portions  34  formed on opposite side edges of the strip portion  33 . The second connecting terminals  39   b  are connected to the terminal connecting portions  34  formed on one side edge of the strip portion  33 . The circuit connecting portions  35  are formed on the side edge on a side opposite to the side edge along which the terminal connecting portions  34  connected to the second connecting terminals  39   b  are formed. Additionally, the engagement holes  39   d  engaged with the lance mechanism disposed in the junction box housing  13  or the connector housing  22   a  ( 22   b ) as described later are formed in the first and second connecting terminals  39   a ,  39   b . However, the holes may not be formed, when the lance mechanism does not lock/fix the connecting terminals similarly as described above. 
     FIGS. 10A and 10B show a top plan view and sectional view of the FPC  30   a  constituting a part of the cable portion  30 . As shown in FIG. 10B, the first and second connecting terminals  39   a ,  39   b  are laid on the terminal connecting portions  34  so as to adhere to the circuit portion  32  on the terminal connecting portions  34 , subsequently subjected, for example, to the resistance welding (series welding) by a pair of electrodes  38   a ,  38   b  of the series welding apparatus (not shown), bonded to the circuit portion  32  and connected to the terminal connecting portions  34 . Additionally, the connecting terminals may also be connected to the terminal connecting portions by the methods other than the above-described resistance welding, such as ultrasonic welding, laser welding and soldering. According to these connection methods, the high connection reliability can be secured. 
     After the first and second connecting terminals  39   a ,  39   b  are connected to the terminal connecting portions  34 , the FPCs  30   a  to  30   d  are superimposed upon one another and the cable portion  30  is formed. In this case, the terminal connecting portions  34  of the respective FPCs  30   a  to  30   d  are formed so that the first and second connecting terminals  39   a ,  39   b  are arranged in the positions corresponding to the connecting terminal arrangement positions of the junction box housing  13  and connector housing  22   a  ( 22   b ). Moreover, as shown in FIG. 11, the circuit connecting portions  35  ( 35   a ,  35   a ′) of the respective FPCs  30   a  to  30   d  are arranged and formed in the corresponding positions so that the circuit connecting portions  35  superimposed upon one another to constitute the desired circuit portion  32  are laminated in an adhering state in the thickness direction of the FPCs  30   a  to  30   d . Moreover, as shown in FIG. 11, the circuit portions  32  of the tip ends of the circuit connecting portions  35  of the laminated FPCs  30   b ,  30   c  are allowed to adhere to each other, subjected to the resistance welding by the pair of electrodes  38   a ,  38   b  and bonded to each other. The circuit portion  32  of the FPC  30   b  and the circuit portion  32  of the FPC  30   c  are connected to each other as one circuit. 
     After the strip FPCs  30   a  to  30   d  are superimposed upon one another to form the cable portion  30  in this manner, for example, the bonded portion of the connecting terminal  39   a  ( 39   b ) to the terminal connecting portion  34  is sealed by the resin molded portion  37  as shown in FIG.  9 . Then, the connection reliability of the bonded portion can be enhanced. Moreover, the terminal connecting portions  34  connected to the first and second connecting terminals  39   a ,  39   b  are arranged as such. The first connecting terminals  39   a  are attached to the junction box housing  13  and the second connecting terminals  39   b  are attached to the connector housing  22   a  ( 22   b ) so that the terminals are arranged in the predetermined terminal arrangement positions. 
     Here, the circuit portion  32  is formed by the so-called solid pattern in the FPC  30   a  shown in FIGS. 10A and 10B. However, for example, when the circuit portion  32  is formed of a plurality of conductor patterns as shown in FIG. 12, a plurality of wiring circuits can be constituted on each of the FPCs  30   a  to  30   d  similarly as the above-described example. Additionally, in the following description, the description of the FPCs  30   a  and  30   d  is omitted, and only the FPCs  30   b  and  30   c  will be described. The contents described hereinafter can be applied to all the FPCs  30   a  to  30   d  constituting the cable portion  30 . 
     As shown in FIG. 12, when the circuit portion  32  is formed so as to include a plurality of conductor patterns, it is possible to construct a plurality of wiring circuits on one FPC  30   b  ( 30   c ). As a result, the number of laminated FPCs can be decreased, and the thinning and weight saving of the cable portion  30  can be promoted similarly as the above-described example. 
     The constitution in which the first connecting terminals  39   a  are attached to the junction box housing  13  of the junction box main body  10  is the same as the constitution described with reference to FIG. 5 in the above-described example, and therefore the description thereof is omitted. 
     FIG. 13A shows partially sectional views showing that the second connecting terminal  39   b  is attached to the connector housing  22   a  ( 22   b ) of the connector portion  20   a  ( 20   b ). 
     As shown in FIG. 13A, in the connector housings  22   a ,  22   b , there are formed: the connector engagement portion  25  engaged with the connector of the outer wiring circuit or the plug connector  21 ; a plurality of terminal containing holes  24   b  through which the second connecting terminals  39   b  are passed and in which the tip ends of the terminals projected into the connector engagement portion  25  are contained; and the insertion hole  27  through which the cable portion  30  having the second connecting terminals  39   b  inserted in the terminal containing holes  24   b  is inserted in a side edge direction of the strip portion  33 . Inside a plurality of terminal containing holes  24   b , there are formed lance portions  26   b  as a lance mechanism, which are engaged with the engagement holes  39   d  of the second connecting terminals  39   b  and lock/fix the connecting terminals  39   b  in the connector housings  22   a ,  22   b . The terminal connecting portions  34  of the FPCs  30   b ,  30   c  constituting the cable portion  30  are contained in the insertion holes  27  in the connector housings  22   a ,  22   b  so that the terminal connecting portions constitute the predetermined connecting terminal arrangement positions in a state shown in FIG.  13 A. The strip portions  33  of the FPCs  30   b ,  30   c  are contained in the case portions  23   a ,  23   b  of the connector portions  20   a ,  20   b  together with the circuit connecting portions  35  formed on one side edge. 
     In this example, the circuit is designed such that the circuit portions  32  for achieving the electric conduction of the FPCs  30   b ,  30   c  cause a short circuit by connecting the circuit connecting portions  35  to one another as described above. The circuit connecting portions  35  may also be formed so that a plurality of circuit portions  32  formed on the same FPC are connected to one another in the predetermined circuit mode, or a plurality of circuit portions  32  formed on a plurality of FPCs are connected to one another in the predetermined circuit mode. Moreover, needless to say, the circuit connecting portions may also be formed so as to realize both requirements at the same time. FIG. 13A shows an example in which the base film  31  is removed only from the tip end of the circuit connecting portion  35 , the circuit portion  32  is extended, and the circuit portions  32  of different layers are connected to one another. FIG. 13B shows an example in which the tip ends of the circuit connecting portions  35  are folded back with the circuit portions  32  disposed in the outside, and the circuit portions  32  of the different layers are connected to one another. 
     In this manner, the circuit connecting portions  35  of the respective FPCs  30   b ,  30   c  can conduct electricity through the desired circuit portions  32  on the FPCs  30   b ,  30   c . A so-called interlayer connection between both the FPCs  30   b ,  30   c  and the wiring circuit constituted over the junction box main body  10  and connector portion  20  can freely be changed. For example, as shown in FIG. 11, when the circuit portion  32  of the circuit connecting portion  35   a  of the FPC  30   b  is connected to the circuit portion  32  of the circuit connecting portion  35   a ′ of the FPC  30   c , as shown in FIGS. 12A and 12B, the second connecting terminal  39   b   1  of the FPC  30   b  and the second connecting terminal  39   b   2  of the FPC  30   c  can constitute one circuit. 
     On the other hand, for example, when a circuit connecting portion  35   b  of the FPC  30   b  is connected to a circuit connecting portion  35   b ′ of the FPC  30   c , the second connecting terminal  39   b   1  of the FPC  30   b  is electrically connected to the first connecting terminal  39   a   1  of the FPC  30   c . Therefore, the circuit portion  32   a  of the FPC  30   b  and the circuit portion  32   c  of the FPC  30   c  can constitute one circuit. In this manner, by the connection of the circuit portions  32  in the circuit connecting portions  35  of the respective FPCs  30   b ,  30   c , the circuit mode of the circuit portion  32  can be changed to a desired mode. For example, when the interlayer connection is performed, many circuit portions  32  are formed on one FPC  30   b  ( 30   c ) and this high-density wiring is possible. Moreover, thereby, the number of layers is decreased, and weight saving can be promoted. Furthermore, the circuit mode of the circuit portion  32  by the circuit connecting portions  35  is changed in accordance with various uses. Thereby, the design change of the circuit is facilitated, and the circuit application range can be broadened. Therefore, it can be expected that the freedom degree of wiring design of the junction box is rapidly enhanced. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general invention concept as defined by the appended claims and their equivalents.