Abstract:
The present invention provides a multiple fuse device that is compatible with various ratings and reduces an increase in manufacturing cost. A multiple fuse device includes an input terminal, an external terminal, a bus bar that includes a circuit portion disposed between the input terminal and the external terminal, and a housing that covers the bus bar. The external terminal includes an integral external terminal integrated with the circuit portion with a fusible portion interposed between the integral external terminal and the circuit portion, and a fuse-side external terminal that pairs up with a fuse connection terminal connected to the circuit portion. The fuse connection terminal and the fuse-side external terminal provided in a pair hold a fuse exteriorly in a removable manner, the fuse having a fusible portion connected between the fuse connection terminal and the fuse-side external terminal.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a fuse device for use in , for example, an electric circuit for an automobile, and more particularly, to a multiple fuse device having a plurality of external terminals. 
       BACKGROUND 
       [0002]    Fuse devices have been used for protecting electric circuits in, for example, an automobile and various electrical components connected to the electric circuits. Specifically, if unintended overcurrent flows into an electric circuit, a fuse device protects an electrical component from the inflow of excessive current in such a manner that a fusible portion thereof is cut by heat generated due to the overcurrent. 
         [0003]    Various kinds of fuse devices have been available in accordance with their applications. For example, JP 2015-022866 A discloses a multiple fuse device for use in a vehicle, the multiple fuse device establishing a connection between a battery and wires for supplying electric power to various electrical components. The multiple fuse device has a plurality of external terminals respectively coupled to the electrical components, and fusible portions interposed between the respective external terminals and the battery to protect the corresponding electrical components from the inflow of excessive current. The multiple fuse device disclosed in JP 2015-022866 A includes a bus bar formed by integral molding using a die. The bus bar includes an input terminal receiving electric power from the battery, the external terminals respectively coupled to the electrical components, a circuit portion disposed between the input terminal and the external terminals, and the fusible portions. 
         [0004]    However, since kinds and sizes of loads such as various electrical components differ depending on types of vehicles, service conditions, and the like, ratings of fusible portions are changed accordingly. Moreover, the changes of the ratings cause changes in the shapes and the like of the fusible portions. This results in change of a die for manufacturing a bus bar of a fuse device, which disadvantageously leads to a great increase in cost. 
       SUMMARY 
       [0005]    Disclosed herein is a multiple fuse device that is compatible with various ratings and reduces an increase in manufacturing cost. 
         [0006]    The multiple fuse device disclosed herein includes an input terminal, an external terminal, a bus bar that includes a circuit portion disposed between the input terminal and the external terminal, and a housing that covers the bus bar. The external terminal includes an integral external terminal integrated with the circuit portion with a fusible portion interposed between the integral external terminal and the circuit portion, and a fuse-side external terminal that pairs up with a fuse connection terminal connected to the circuit portion. The fuse connection terminal and the fuse-side external terminal provided in a pair hold a fuse exteriorly in a removable manner, the fuse having a fusible portion connected between the fuse connection terminal and the fuse-side external terminal. 
         [0007]    According to this configuration, the multiple fuse device easily copes with a change in rating of a fusible portion associated with changes in types of vehicles, service conditions, and the like in such a manner that a fuse with a desired rating is appropriately mounted to the multiple fuse device. Unlike the conventional art, therefore, the multiple fuse device disclosed herein has no need to change a die depending on a change in rating of a fusible portion, which advantageously reduces manufacturing cost. 
         [0008]    As described above, the multiple fuse device disclosed herein is compatible with various ratings and reduces an increase in manufacturing cost. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0009]      FIG. 1A  is a perspective view of a bus bar of a multiple fuse device according to the present invention; 
           [0010]      FIG. 1B  is a front view of the bus bar; 
           [0011]      FIG. 1C  is a plan view of the bus bar; 
           [0012]      FIG. 2A  is a front view of a fuse-side external terminal of the multiple fuse device according to the present invention; 
           [0013]      FIG. 2B  is a side view of the fuse-side external terminal; 
           [0014]      FIG. 3A  is a perspective view of a lower housing that constitutes a housing of the multiple fuse device according to the present invention; 
           [0015]      FIG. 3B  is a plan view of the lower housing; 
           [0016]      FIG. 3C  is a bottom view of the lower housing; 
           [0017]      FIG. 4A  is a perspective view of an upper housing that constitutes the housing of the multiple fuse device according to the present invention; 
           [0018]      FIG. 4B  is a plan view of the upper housing; 
           [0019]      FIG. 4C  is a bottom view of the upper housing; 
           [0020]      FIG. 5  is an exploded perspective view of the multiple fuse device according to the present invention; 
           [0021]      FIG. 6A  is an exploded perspective view of the multiple fuse device according to the present invention; 
           [0022]      FIG. 6B  is a plan view of the multiple fuse device according to the present invention; 
           [0023]      FIG. 7A  is a front view of a fuse to be mounted to the multiple fuse device according to the present invention; 
           [0024]      FIG. 7B  is a perspective view of the multiple fuse device according to the present invention to which the fuse is mounted; and 
           [0025]      FIG. 7C  is a sectional view taken along line A-A in  FIG. 7B . 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    An embodiment of the present invention will be described below with reference to the drawings. It should be noted that shapes, materials, and the like of members constituting a multiple fuse device to be described in the following embodiment are merely examples, and the present invention is therefore not limited thereto. Like reference numbers refer to like elements throughout the various drawings. 
         [0027]      FIGS. 1A to 1C  illustrate a bus bar  100  of a multiple fuse device according to the present invention. The bus bar  100  is formed from a single, thin metal plate by integral molding using a die. The bus bar  100  includes an input terminal  110  electrically connectable to, for example, a battery, a plurality of integral external terminals ( 120 A and  120 B), and a plurality of fuse connection terminals ( 130 A to  130 D). The input terminal  110  is connected to a circuit portion  112 , and the integral external terminals  120  are respectively connected to the circuit portion  112  via fusible portions  113 . Therefore, when overcurrent flows from a power supply such as the battery connected to the input terminal  110 , the fusible portions  113  are cut to protect loads such as various electrical components coupled to the integral external terminals  120  from the inflow of excessive current. 
         [0028]    Each of the fuse connection terminals ( 130 A to  130 D) has a proximal end connected to the circuit portion  112 , and a distal end coupled to a fuse-side external terminal  140  coupled to an electrical component via a fuse to be described later. Therefore, when overcurrent flows from the power supply connected to the input terminal  110 , fusible portions of the fuses respectively connected to the fuse connection terminals  130  are cut to protect loads coupled to the fuse-side external terminals  140  respectively from the inflow of excessive current. 
         [0029]    Next, a brief description will be given of a method for molding the bus bar  100 . First, a flat plate member having uniform thickness and made of a conductive metal such as copper or a copper alloy is die-cut into a predetermined shape, using a press machine or the like. Next, a region corresponding to the input terminal  110  is bent into an approximately 90° angle, and a region corresponding to the integral external terminals  120  is also bent into an approximately 90° angle. The bus bar  100  illustrated in  FIGS. 1A to 1C  is thus prepared. 
         [0030]    With reference to  FIGS. 2A and 2B , next, a description will be given of the fuse-side external terminals  140 . Each of the fuse-side external terminals  140  is prepared as follows. That is, a flat plate member having uniform thickness and made of a conductive metal such as copper or a copper alloy is die-cut into a predetermined shape illustrated in  FIGS. 2A and 2B , using a press machine or the like. As will be described in detail later, each of the fuse-side external terminals  140  has an upper end  141  and a lower end  142  formed into flat plate-shaped male terminals to be inserted into a fuse and a female terminal of an external connector, respectively. 
         [0031]    With reference to  FIGS. 3A to 3C , next, a detailed description will be given of a lower housing  200  that constitutes a housing  400  of the multiple fuse device according to the present invention. The lower housing  200  is made of, for example, an insulating synthetic resin and has an approximately rectangular parallelepiped shape. The lower housing  200  has, on an edge of its upper side, recesses ( 230 A to  230 D) formed with predetermined pitches such that the fuse connection terminals  130  of the bus bar  100  respectively protrude from the recesses ( 230 A to  230 D). 
         [0032]    The lower housing  200  also has, at an approximately center of its upper side, slits ( 240 A to  240 D) formed in one-to-one correspondence with the recesses ( 230 A to  230 D) such that the lower ends  142  of the fuse-side external terminals  140  are respectively inserted into the slits ( 240 A to  240 D). Each of the slits ( 240 A to  240 D) is a through-hole extending from the front side to the back side of the lower housing  200 . 
         [0033]    The lower housing  200  also has, on its upper side, an input terminal placement portion  210  for placing the input terminal  110  of the bus bar  100 , an external terminal placement portion  220 A for placing the integral external terminal  120 A of the bus bar  100 , and an external terminal placement portion  220 B for placing the integral external terminal  120 B of the bus bar  100 . The input terminal placement portion  210 , the external terminal placement portion  220 A, and the external terminal placement portion  220 B have a hollow shape so as to achieve stable placement of the input terminal  110 , the integral external terminal  120 A, and the integral external terminal  120 B. 
         [0034]    The lower housing  200  also has, on its lateral side, an accommodating portion  212  having a hollow shape to accommodate the circuit portion  112  of the bus bar  100 . The accommodating portion  212  extends in a direction at approximately right angles to the upper side of the lower housing  200 . The accommodating portion  212  has a plurality of engagement protrusions  214  that are engageable in corresponding engagement holes  114  in the bus bar  100 . 
         [0035]    As illustrated in  FIG. 3C , the lower housing  200  has, on its bottom side, connector ports ( 250 A to  250 D) into and to which connectors CN to be described later are insertable and attachable. The connector ports  250  have bottom surfaces to which the corresponding slits  240  extend. Therefore, the lower ends  142  of the fuse-side external terminals  140  inserted into the slits  240  from the front side (see  FIG. 3A ) of the lower housing  200  pass through the lower housing  200  to the back side of the lower housing  200  and protrude from the slits  240  in the bottom surfaces of the connector ports  250 . 
         [0036]    With reference to  FIGS. 4A to 4C , next, a detailed description will be given of an upper housing  300  that constitutes the housing  400 . The upper housing  300  is made of, for example, an insulating synthetic resin and has an approximately rectangular parallelepiped shape. The upper housing  300  has, in its upper side, through-holes ( 330 A to  330 D) through which the fuse connection terminals  130  of the bus bar  100  pass. The through-holes ( 330 A to  330 D) are formed with predetermined pitches in one-to-one correspondence with through-holes ( 340 A to  340 D) through which the upper ends  141  of the fuse-side external terminals  140  pass. The upper housing  300  also has a fuse port  350 A formed to surround the through-hole  330 A and the through-hole  340 A provided in a pair. Likewise, the upper housing  300  also has fuse ports ( 350 B to  350 D) respectively formed to surround the through-holes ( 330 B to  330 D) and the through-holes ( 340 B to  340 D) provided in a pair. 
         [0037]    The upper housing  300  also has, on its upper side, an input terminal window  310  for exposing the input terminal  110  of the bus bar  100 , an external terminal window  320 A for exposing the integral external terminal  120 A of the bus bar  100 , and an external terminal window  320 B for exposing the integral external terminal  120 B of the bus bar  100 . The upper housing  300  also has, on its upper side, a partition wall  315  formed between the respective windows. 
         [0038]    The upper housing  300  also has, on its lateral side, an accommodating wall  312  for covering and concealing the circuit portion  112  of the bus bar  100 . The upper housing  300  also has, on its both ends, fixation holes  316  that engage with fixation protrusions  216  of the lower housing  200  to firmly fix the upper housing  300  to the lower housing  200 . 
         [0039]    With reference to  FIG. 5 , next, a description will be given of a way to assemble the multiple fuse device  600  according to the present invention. First, the bus bar  100  is put to the lateral side of the lower housing  200  such that the circuit portion  112  of the bus bar  100  is accommodated in the accommodating portion  212  of the lower housing  200 , the input terminal  110  of the bus bar  100  is placed on the input terminal placement portion  210  of the lower housing  200 , the integral external terminal  120 A of the bus bar  100  is placed on the external terminal placement portion  220 A of the lower housing  200 , and the integral external terminal  120 B of the bus bar  100  is placed on the external terminal placement portion  220 B of the lower housing  200 . Moreover, the fuse connection terminals  130  are aligned with the corresponding recesses  230 . In the alignment, the engagement protrusions  214  of the lower housing  200  are engaged in the corresponding engagement holes  114  in the bus bar  100 , so that the bus bar  100  can be placed at its appropriate position and this placed state is easily maintained. 
         [0040]    In placing the input terminal  110  on the input terminal placement portion  210 , a flange P 1 B of a connecting bolt P 1  is interposed between the input terminal  110  and the input terminal placement portion  210 , so that the connecting bolt P 1  is fixed on the input terminal placement portion  210 . Likewise, a flange PAB of a connecting bolt PA is interposed between the integral external terminal  120 A and the external terminal placement portion  220 A and a flange PBB of a connecting bolt PB is interposed between the integral external terminal  120 B and the external terminal placement portion  220 B, so that the connecting bolt PA and the connecting bolt PB are both fixed. 
         [0041]    Next, the lower end  142 A of the fuse-side external terminal  140 A is inserted into the slit  240 A from above the lower housing  200  so that the fuse-side external terminal  140 A is mounted to the lower housing  200 . Likewise, the fuse-side external terminals  140 B to  140 D are also inserted into the corresponding slits  240 B to  240 D and are mounted to the lower housing  200 . 
         [0042]    As illustrated in  FIGS. 6A and 6B , thus, the fuse connection terminal  130 A and the fuse-side external terminal  140 A provided in a pair are placed on the upper side of the lower housing  200  so as to face each other. Likewise, the fuse connection terminals  130 B to  130 D and the fuse-side external terminals  140 B to  140 D respectively provided in a pair are also placed to face each other. 
         [0043]    As illustrated in  FIGS. 6A and 6B , next, the upper housing  300  is mounted to the lower housing  200  from above the lower housing  200  so as to cover the lower housing  200 . Specifically, the fuse connection terminals  130  are inserted into the corresponding through-holes  330  in the fuse ports  350 , and the fuse-side external terminals  140  are inserted into the corresponding through-holes  340  in the fuse ports  350 . Moreover, the input terminal window  310  is located above the input terminal  110 , the external terminal window  320 A is located above the integral external terminal  120 A, and the external terminal window  320 B is located above the integral external terminal  120 B. When the fixation protrusions  216  of the lower housing  200  are engaged in the fixation holes  316  in the upper housing  300 , the lower housing  200  and the upper housing  300  are firmly fixed together to constitute the housing  400 . As a result, the bus bar  100  is covered with the housing  400 , and the multiple fuse device  600  according to the present invention is thus assembled. 
         [0044]    With reference to  FIGS. 7A to 7C , next, a description will be given of the use of the multiple fuse device  600  according to the present invention. 
         [0045]    In the use of the multiple fuse device  600 , a user mounts fuses  500  with desired ratings to the multiple fuse device  600 . The fuses  500  are now described. As illustrated in  FIG. 7A , the fuse  500 A is an existing general fuse having an approximately rectangular parallelepiped shape. The fuse  500 A is entirely covered with a housing  510 A made of, for example, an insulating synthetic resin. The fuse  500 A includes a female terminal  530 A and a female terminal  540 A each made of a metal. The female terminal  530 A and the female terminal  540 A are connected to each other with a fusible portion  550 A. 
         [0046]    As illustrated in  FIG. 7B , the fuse  500 A is inserted into the fuse port  350 A of the multiple fuse device  600  and is thus mounted to the multiple fuse device  600 . Likewise, the fuses  500 B to  500 D are inserted into the corresponding fuse ports  350 B to  350 D and are thus mounted to the multiple fuse device  600 . The fuses  500 A to  500 D are identical in structure with one another except ratings of the respective fusible portions  550 A to  550 D. Therefore, each of the fuses  500 A to  500 D may be inserted into any fuse port  350 . Accordingly, the user of the multiple fuse device  600  may mount a fuse  500  with a desired rating to a fuse port  350  of choice in accordance with an electrical component to be coupled to the multiple fuse device  600 . The fuses  500  are removable from the fuse ports  350 . Therefore, the fuses  500  are exchangeable repeatedly in accordance with, for example, a change in rating. 
         [0047]    Next, a brief description will be given of functional effects of the fuses  500 . As illustrated in  FIG. 7C , the fuse connection terminal  130 A of the bus bar  100  is inserted into and connected to the female terminal  530 A of the fuse  500 A and the upper end  141 A of the fuse-side external terminal  140 A is inserted into and connected to the female terminal  540 A of the fuse  500 A, with the fuse  500 A mounted to the fuse port  350 A. Moreover, the lower end  142 A of the fuse-side external terminal  140 A protrudes from the connector port  250 A on the back side and is connected to a female terminal C 1  of a connector CN mounted to the connector port  250 A. 
         [0048]    Under normal conditions, current supplied from the power supply connected to the input terminal  110  flows from the circuit portion  112  of the bus bar  100  to the fuse connection terminal  130 A and then flows to the fuse-side external terminal  140 A via the fusible portion  550 A. The current then flows from the lower end  142 A of the fuse-side external terminal  140 A to a wire C 2  connected to the female terminal C 1  of the connector CN and is supplied to a load such as an electrical component connected to the wire C 2 . If overcurrent is supplied from the power supply connected to the input terminal  110 , the fusible portion  550 A is cut to protect the load such as the electrical component connected to the wire C 2  from the inflow of the overcurrent. Likewise, the fuses  500 B to  500 D protect loads such as various electrical components coupled thereto from the inflow of overcurrent supplied from the power supply connected to the input terminal  110 . 
         [0049]    With regard to the integral external terminal  120 A and the integral external terminal  120 B, if overcurrent is supplied from the power supply connected to the input terminal  110 , the fusible portion  113 A and the fusible portion  113 B are cut to protect loads such as various electrical components coupled to the integral external terminal  120 A and the integral external terminal  120 B, respectively. 
         [0050]    As described above, the multiple fuse device  600  according to the present invention easily copes with a change in rating of a fusible portion associated with changes in types of vehicles, service conditions, and the like in such a manner that the user appropriately mounts a fuse  500  with a desired rating to the multiple fuse device  600 . Unlike the conventional art, the multiple fuse device  600  according to the present invention has no necessity to change a die depending on a change in rating of a fusible portion, which brings about a reduction in manufacturing cost. 
         [0051]    In addition, the multiple fuse device  600  according to the present invention achieves the combined use of the fusible portions  113  integrated with the bus bar  100  and the fusible portions  550  of the removable fuses  500 . This configuration can reduce a necessity to change a die as much as possible even when a rating is changed. Therefore, the multiple fuse device  600  according to the present invention can produce an advantageous effect of reducing an effort to mount a fuse  500  while producing an advantageous effect of reducing manufacturing cost as much as possible. Specifically, in the multiple fuse device  600 , the fusible portions  113  are integrated with a part of the bus bar  100 . It is therefore considered that a change in rating of a load coupled to each fusible portion  113  causes a necessity to change a die for manufacturing the bus bar  100 . To this end, if the multiple fuse device  600  is designed to omit all the fusible portions  113  and to employ only the fusible portions  550  of the removable fuses  500 , a die is not changed at all even when a rating is changed. However, this configuration increases work for mounting the fuses  500 . 
         [0052]    Typically, a power supply such as a battery for use in an automobile is connected to both a load (e.g., an alternator, a starter) of which the rating does not relatively change depending on changes in types of vehicles, service conditions, and the like and a load (e.g., a radiator) of which the rating relatively changes depending on changes in types of vehicles, service conditions, and the like. 
         [0053]    In view of this, the present invention provides the configuration where a load of which the rating does not relatively change is coupled to each fusible portion  113  integrated with the bus bar  100 , whereas a load of which the rating relatively changes is coupled to the fusible portion  550  of each fuse  500  separate from the bus bar  100 . As a result, it becomes unnecessary to change the shape and the like of each fusible portion  113  coupled to a load of which the rating does not relatively change and it becomes also unnecessary to change a die. Therefore, the manufacturing cost can be reduced as much as possible. Moreover, employing the integral fusible portions  113  can eliminate the work for mounting the fuses  500 . On the other hand, changing each fuse  500  can easily cope with a load of which the rating relatively changes. 
         [0054]    The multiple fuse device  600  according to the present invention includes the connector ports  250  for mounting the connectors CN. This configuration reduces a conventional effort of fastening with a bolt. The fastening with a bolt means that, as illustrated in  FIG. 7B , external terminals coupled to loads such as various electrical components are fastened to the connecting bolt P 1 , connecting bolt PA, and connecting bolt PB with nuts or the like. 
         [0055]    The multiple fuse device according to the present invention is not limited to the foregoing embodiment, and various modifications and combinations may be made within the scope of the appended claims and the scope of the embodiment. These modifications and combinations are also encompassed within the technical range of the present invention.