Abstract:
A fuse unit including a fuse element therein includes a first resin body and a second resin body. The second resin body is connected to the first resin body by a hinge portion and configured to be bended around the hinge portion with respect to the first resin body. A pair of first side walls and a pair of second side walls are provided on the first resin body and the second resin body respectively and extend in a direction intersecting an axis of the bending of the second resin body. A pair of engaging parts are provided at the lock arms provided at the first side walls respectively respectively, and each of which has a first inclined face. A pair of engaged parts are provided at the second side walls respectively, and corresponds to the engaging parts respectively, and each of which has a second inclined face configured to contact the first inclined face in surface contact in a state that the second resin body is bended. The first inclined face and the second inclined face are formed along a direction intersecting a direction of a reaction force by springback of the fuse element caused by the bending of the second resin body.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a fuse unit which is directly attached to a battery installed in an automobile and supplies electric power of the battery to an electric wire for supplying electric power. 
       BACKGROUND ART 
       [0002]      FIG. 12  shows a conventional fuse unit  100  described in PTL 1. The fuse unit  100  is formed by building a fuse element (not shown) made of a conductive metal plate into a resin body  110 . The resin body  110  is divided into forward and backward division bodies  120 ,  130  in a state of extending in a plane shape and in the case of being attached to a battery, the division bodies  120 ,  130  are bent in an L shape as shown in  FIG. 12 . The division bodies  120 ,  130  are bent about a hinge part of the fuse element exposed from the portion between the division bodies  120 ,  130 . The fuse unit  100  is used in a state where the fuse unit  100  is bent to L shape, thus it can cope with circuit arrangement inside narrow space. 
         [0003]    In the use state of the fuse unit as described above, it is necessary to hold a L-shaped bent state, so that the conventional fuse unit  100  is constructed as described below. 
         [0004]    A regulation wall  140  facing an inner surface wall  121  of one division body  120  is erected in an inner surface wall  131  of the other division body  130 , and an inclined wall surface  141  inclined in a direction separate from the inner surface wall  121  of one division body  120  is formed in the regulation wall  140 . Also, bending rigidity of the regulation wall  140  is increased by disposing fall-prevention ribs  143  in both ends of the regulation wall  140 . 
         [0005]    Further, a lock arm  150  having a hook part  151  is disposed in one division body  120  and also a notch part  153  with which the hook part  151  engages is disposed in the regulation wall  140  of the other division body  130  and first lock means is formed. Also, a locking projection (not shown) is disposed in one division body  120  and an engaging groove  160  in which the locking projection locks is disposed in the other division body  130  and second lock means is formed. The engaging groove  160  is disposed in an extension wall  165  from side surface walls  133 ,  135  in the other division body  130 . 
         [0006]    When the other division body  130  is bent with respect to one division body  120  in such a structure, the regulation wall  140  of the other division body  130  abuts on the inner surface wall  121  of one division body  120 . Also, by hooking the hook part  151  of the lock arm  150  in one division body  120  to the notch part  153 , the lock arm  150  engages with the notch part  153  and is locked and also the locking projection of one division body  120  engages with the engaging groove  160  of the other division body  130  and is locked. Consequently, the state of bending the two division bodies in the L shape can be held. 
       Citation List 
       [0007]    Patent Literature 
         [0008]    [PTL  1 ] JP-A-2002-329457 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0009]    In the conventional fuse unit  100 , in a lock state in which the engaging groove  160  engages with the locking projection which is the second lock means, a gap may occur between the notch part  153  and the hook part  151  of the lock arm  150  which is the first lock means and due to occurrence of this gap, a lock force reduces and the lock state cannot be held in the first lock means. 
         [0010]    Consequently, all the loads of springback from the built-in fuse element bent in the L shape act on the second lock means including the engaging groove  160  and an engaging projection disposed inside the extension wall  165 , so that a holding force for holding the L-shaped bent state cannot be ensured sufficiently and there is a problem that the fuse unit  100  may be damaged. 
         [0011]    Therefore, an object of the invention is to provide a fuse unit capable of being surely subjected to a load of springback from a built-in fuse element and holding a bent state of division bodies and preventing damage. 
       Solution to Problem 
       [0012]    In order to achieve the object, according to the present invention, there is provided a fuse unit including a fuse element therein, the fuse unit having: a first resin body; a second resin body connected to the first resin body by a hinge portion and configured to be bended around the hinge portion with respect to the first resin body; a first opposing wall provided on the first resin body; a second opposing wall provided on the second resin body and opposing the first opposing wall, so that the hinge portion is disposed between the first opposing wall and the second opposing wall; a pair of first side walls provided on the first resin body and extending in a direction intersecting an axis of the bending of the second resin body; a pair of second side walls provided on the second resin body and extending in a direction intersecting the axis of the bending of the second resin body; a pair of lock arms provided at the first side walls respectively; a pair of engaging parts, provided at the lock arms respectively, and each of which having a first inclined face; and a pair of engaged parts, provided at the second side walls respectively, and corresponding to the engaging parts respectively, and each of which having a second inclined face configured to contact the first inclined face in surface contact in a state that the second resin body is bended, wherein the first inclined face and the second inclined face are formed along a direction intersecting a direction of a reaction force by springback of the fuse element caused by the bending of the second resin body. 
         [0013]    The fuse unit may be configured such that: each of the engaging parts is a lock projection; each of the engaged parts is a protrusion; and the lock projection and the protrusion are configured to contact to each other and to slide according to the bending of the second resin body. 
         [0014]    The fuse unit may be configured such that: the lock arms have flexibility; and the lock arms are configured to be deformed outward of the first side walls according to the bending of the second resin body. 
         [0015]    The fuse unit may be configured such that: a straight line parallel to the first inclined face and extended from the first inclined face in a state the first inclined face and the second inclined face contact in surface contact intersects the axis of the bending of the second resin body. 
       Advantageous Effects of Invention 
       [0016]    According to the present invention, the lock arms are disposed in the side wall parts of both sides of one division body and also the protrusions are disposed in the side wall parts of both sides of the other division body and when the two division bodies are bent, a state in which the first inclined surfaces formed in the lock arms are aligned with the second inclined surfaces disposed in the protrusions is obtained. In such a structure, the two division bodies are engaged in the side wall parts of both sides, so that a sure lock state is obtained. 
         [0017]    Moreover, the first inclined surfaces and the second inclined surfaces are formed along the direction intersecting with respect to the reaction force by springback of the fuse element based on bending of the division bodies, so that in a state of alignment between the first inclined surfaces and the second inclined surfaces, these surfaces can surely be subjected to the reaction force by springback. 
         [0018]    In the present invention, it can surely be subjected to a load of springback from the fuse element, so that a bent state of the division bodies can be held and damage can be prevented. 
         [0019]    In addition, according to the present invention, the slide surface parts for sliding in mutual contact are formed in the lock projection and the protrusion, so that the lock projection and the protrusion slide relatively in the case of bending the division bodies. As a result of this, the first inclined surfaces of the lock projections are smoothly aligned with the second inclined surfaces of the protrusions and a lock of the bent state can be performed smoothly. 
         [0020]    In addition, according to the present invention, the interference parts formed in the lock projections and the protrusions flex the lock arms in the case of bending the division bodies, so that the lock arms do not become an obstacle to bending of the division bodies and the first inclined surfaces can smoothly be aligned with the second inclined surfaces. 
         [0021]    In addition, according to the present invention, the extension line of alignment between the first inclined surfaces and the second inclined surfaces matches with the center of bending of the division bodies, so that it can surely be subjected to the reaction force of springback of the fuse element based on bending of the division bodies and the bent state of the division bodies can be held more stably. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0022]      FIG. 1  is a perspective view before bending of a fuse unit  1  of one embodiment of the invention. 
           [0023]      FIG. 2  is a perspective view showing a lock arm portion in the fuse unit  1 . 
           [0024]      FIG. 3  is a perspective view showing a protrusion portion in the fuse unit  1 . 
           [0025]      FIG. 4  is a view showing the lock arm portion in the fuse unit  1 . 
           [0026]      FIG. 5  is a view showing the protrusion portion in the fuse unit  1 . 
           [0027]      FIG. 6  is a plan view before two division bodies are bent. 
           [0028]      FIG. 7  is a side view before the two division bodies are bent. 
           [0029]      FIGS. 8A ,  8 B and  8 C are side views showing operations of bending of the two division bodies. 
           [0030]      FIG. 9  is a perspective view showing a state of bending the two division bodies. 
           [0031]      FIG. 10  is a plan view showing the state of bending the two division bodies. 
           [0032]      FIG. 11  is a side view taken on line E-E of  FIG. 10  showing the state of bending the two division bodies. 
           [0033]      FIG. 12  is a perspective view showing a state of bending a conventional fuse unit. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0034]    The invention will hereinafter be described concretely by an illustrated embodiment. 
         [0035]      FIGS. 1 to 11  show a fuse unit  1  of one embodiment of the invention, and  FIG. 1  is the whole perspective view of the fuse unit  1  of one embodiment of the invention, and  FIG. 2  is a perspective view of a lock arm portion, and  FIG. 3  is a perspective view of a protrusion portion, and  FIG. 4  is a view of the lock arm portion (a view taken on arrow IV-IV in  FIG. 7 ), and  FIG. 5  is a plan view of the protrusion portion (a view taken on arrow V-V in  FIG. 7 ), and  FIG. 6  is a plan view before bending of the fuse unit  1 , and  FIG. 7  is a side view of the fuse unit  1 , and  FIG. 8  is a side view showing an operation of bending, and  FIG. 9  is a perspective view showing a state of bending the fuse unit  1 , and  FIG. 10  is a plan view showing the state of bending the fuse unit  1 , and  FIG. 11  is a side view showing the state of bending the fuse unit  1  (a view taken on arrow E-E in  FIG. 10 ). 
         [0036]    As shown in  FIGS. 1 and 9 , the fuse unit  1  of this embodiment includes a fuse element (not shown) and an insulating resin body  2  into which the fuse unit is built. The fuse unit  1  distributes and supplies electric power of a battery to a power source for electric power supply by being directly mounted in the battery installed in a vehicle. 
         [0037]    The fuse element is made of a conductive metal plate and is molded integrally with the resin body  2  by being inserted into a metal mold in the case of molding the resin body  2 . Plural fuses or tab terminals (not shown) are formed in the fuse element. The middle of the fuse element forms a flexible hinge part  3  (see  FIGS. 6 to 8 ) exposed from the resin body  2 , and the resin body  2  can be bent about the hinge part  3  as described below. 
         [0038]    The resin body  2  is formed by two division bodies  5 ,  7 . The two division bodies  5 ,  7  are divided around the hinge part  3  of the fuse element, and the hinge part  3  of the fuse element is exposed to the middle of the division bodies  5 ,  7 . The resin body  2  described above is bent so as to form an L shape about the hinge part  3  of the fuse element. By being bent in the L shape thus, the fuse unit  1  can cope with arrangement of many circuits inside narrow space. Hereinafter, the division body  5  is described as one division body  5  and the division body  7  is described as the other division body  7 . 
         [0039]    As shown in  FIGS. 1 and 9 , a terminal connection part  81  of a battery terminal, a terminal connection part  82  of an alternator terminal and a terminal connection part  83  of a starter motor terminal are formed in the other division body  7 . One division body  5  has a fuse built-in part  85  and a tab terminal built-in part  86 . 
         [0040]    An opposed wall part  51  and an opposed wall part  71  mutually opposed around the hinge part  3  of the fuse element are formed in one division body  5  and the other division body  7  (see  FIGS. 1 ,  6  and  9 ). Side wall parts  52 ,  53  of both sides extending in an intersection direction orthogonal to the opposed wall part  51  are parallel formed in the opposed wall part  51  in one division body  5 , and side wall parts  72 ,  73  of both sides extending in an intersection direction orthogonal to the opposed wall part  71  are parallel formed in the opposed wall part  71  in the other division body  7 . Also, all the side wall parts  52 ,  53  and the side wall parts  72 ,  73  become parallel between the division bodies  5 ,  7 . 
         [0041]    A pair of lock arms  11 ,  12  is formed in one division body  5 . The lock arms  11 ,  12  are disposed in the side wall parts  52 ,  53  in one division body  5  and are positioned in the side of the hinge part  3  in the side wall parts  52 ,  53 . By disposing the lock arms  11 ,  12  in the side wall parts  52 ,  53 , the lock arms  11 ,  12  are positioned in both ends of a width direction which is a longitudinal direction of the hinge part  3  in one division body  5 . The lock arms  11 ,  12  are disposed so as to stand from inner wall portions of the corresponding side wall parts  52 ,  53  in a thickness direction of the conductive metal plate of the fuse element positioned in the side of the division body  5 . Also, the lock arms  11 ,  12  are formed in some thin shape and consequently, flexibility capable of flexing in a thickness direction which is equal to the width direction of the fuse unit  1  is given. 
         [0042]    Lock projections  13 ,  14  which are an example of an engaging part for lock are respectively disposed in the respective lock arms  11 ,  12 . The lock projection  13  is disposed in the lock arm  11  and the lock projection  14  is disposed in the lock arm  12 . These lock projections  13 ,  14  are disposed on opposed surfaces of the lock arms  11 ,  12 . In addition, details of the lock projections  13 ,  14  will be described below. 
         [0043]    A pair of protrusions  17 ,  18  is disposed in the other division body  7 . The protrusions  17 ,  18  which are an example of an engaged part for lock are disposed in the side wall parts  72 ,  73  in the other division body  7  and are positioned in the side of the hinge part  3  in the side wall parts  72 ,  73 . By disposing the protrusions  17 ,  18  in the side wall parts  72 ,  73  of the other division body  7 , the protrusions  17 ,  18  are positioned in both ends of the width direction in the other division body  7 . In this case, the protrusion  17  corresponds to the lock projection  13  of the lock arm  11  and the protrusion  18  corresponds to the lock projection  14  of the lock arm  12 . 
         [0044]    As shown in  FIGS. 1 and 2 , the lock projection  13  of the side of the lock arm  11  is disposed so as to protrude from the opposed surface of the lock arm  12  to the inside of the one division body  5  toward the lock arm  12 , and a top surface of the lock projection  13  is formed in a slide surface part  21 . The slide surface part  21  is formed in substantially a trapezoid surface and interference parts  22 ,  23  are consecutively disposed in two sides of the outside. The interference parts  22 ,  23  are formed by surfaces obliquely erected from the lock arm  11 . A first inclined surface  25  is formed in the portion opposed to the interference parts  22 ,  23  in the lock projection  13 . The first inclined surface  25  is formed in the surface obliquely erected from the lock arm  11 . An inclination of the first inclined surface  25  is set in a direction, for example, an orthogonal direction, intersecting with respect to a reaction force by springbuck at the time of folding and plastically deforming the hinge part  3  of the fuse element. That is, the first inclined surface  25  is formed by a portion of the plane including the central axis of bending in the hinge part  3 . 
         [0045]    The lock projection  14  of the side of the lock arm  12  is formed so as to become plane-symmetrical to the lock projection  13  of the side of the lock arm  11 , that is symmetrical with respect to a plane orthogonal to the central axis of bending of the hinge part  3  through the center of the width direction of the fuse unit  1 , and as shown in  FIG. 7 , the top surface is formed in a slide surface part  31  and two sides of the outside of the slide surface part  31  are formed in interference parts  32 ,  33  and also a first inclined surface  35  is formed in the portion opposed to the interference parts  32 ,  33 . Like the first inclined surface  25  of the lock projection  13 , the first inclined surface  35  of the lock projection  14  is inclined in the direction intersecting with respect to the reaction force by springback of the fuse element. 
         [0046]    As shown in  FIG. 3 , a top surface of the protrusion  18  corresponding to the lock projection  14  of the lock arm  12  is formed in a slide surface part  36  corresponding to the planar slide surface part  31  of the lock projection  14 . Interference parts  37 ,  38  obliquely to the width direction of the fuse unit  1  erected from the side wall part  73  to the slide surface part  36  are formed in two sides of the outside of the slide surface part  36 . The interference parts  37 ,  38  correspond to the interference parts  32 ,  33  in the lock projection  14 . A second inclined surface  39  falling in an oblique direction from the slide surface part  36  is consecutively disposed in the portion opposed to the interference parts  32 ,  33  in the slide surface part  36 . Like the first inclined surface  35  of the lock projection  14 , the second inclined surface  39  is inclined in the direction intersecting with respect to the reaction force by springback of the fuse element. 
         [0047]    When the two division bodies  5 ,  7  are bent at the hinge part  3 , the interference parts  37 ,  38  of the protrusion  18  first interfere with the interference parts  32 ,  33  of the lock projection  14 . By this interference, the lock arm  12  operates so as to flex toward the outside of the side wall part  53  of one division body  5 . Subsequently, the slide surface part  36  of the protrusion  18  makes slidable contact with the slide surface part  31  of the lock projection  14 . Further, in a state of finishing bending the two division bodies at the hinge part  3  by 90°, the lock projection  14  gets over the protrusion  18  and contact between the slide surface part  36  and the slide surface part  31  is eliminated and the lock arm  12  is restored. Then, the second inclined surface  39  of the protrusion  18  is aligned with the first inclined surface  35  of the lock projection  14  in surface contact between the surfaces  39  and  35  is made. 
         [0048]    Though illustration is omitted, the protrusion  17  corresponding to the lock projection  13  of the lock arm  11  is formed so as to become plane-symmetrical to the protrusion  18  described above, and a slide surface part corresponding to the slide surface part  21  of the lock projection  13 , interference parts corresponding to the interference parts  22 ,  23  and a the second inclined surface corresponding to the first inclined surface  25  are formed. Like the first inclined surface  25  of the lock projection  13 , the second inclined surface of the protrusion  17  is inclined in the direction intersecting with respect to the reaction force by springback of the fuse element. 
         [0049]    When the two division bodies  5 ,  7  are bent, like the lock projection  14  or the protrusion  18 , simultaneously, the interference parts of the protrusion  17  first interfere with the interference parts  22 ,  23  of the lock projection  13  and by this interference, the lock arm  11  operates so as to flex toward the outside of the side wall part  52  of one division body  5 . Subsequently, the slide surface part of the protrusion  17  makes slidable contact with the slide surface part  21  of the lock projection  13 . Further, the second inclined surface of the protrusion  17  is aligned with the first inclined surface  25  of the lock projection  13 . 
         [0050]    Next, an operation of bending the resin body  2  of this embodiment will be described by  FIGS. 7 ,  8 ,  10  and  11 . These drawings show an operation of the lock arm  12  of the division body  5  and the protrusion  18  of the division body  7  corresponding to this lock arm  12 . As can be seen already, the lock arm  11  and the protrusion  17  corresponding to this lock arm  11  operate similarly. 
         [0051]      FIG. 7  shows a state before bending of the division bodies  5 ,  7 , and the division bodies  5 ,  7  are bent from this state.  FIG. 8A  shows the original state of bending one division body  5  to the side of the other division body  7  about the hinge part  3  of the fuse element. In the state of  FIG. 8A , the interference parts  32 ,  33  of the lock projection  14  disposed in the lock arm  12  approach the interference parts  37 ,  38  of the protrusion  18  of the side of the other division body  7 . 
         [0052]      FIG. 8B  shows a state of further bending one division body  5 , and the interference parts  32 ,  33  of the lock projection  14  interfere with the interference parts  37 ,  38  of the protrusion  18  in this state. By this interference, the lock arm  12  flexes to the outside of the side wall part  53 . Also in the side of the lock arm  11 , a similar operation is performed and the interference parts  22 ,  23  of the lock projection  13  interfere with the interference parts of the protrusion  17  of the other division body  7  and by this interference, the lock arm  11  flexes to the outside of the side wall part  52 . Thus, the lock arms  11 ,  12  flex to the outsides of the side wall parts  52 ,  53  and thereby, one division body  5  can be bent smoothly. 
         [0053]      FIGS. 8C ,  10  and  11  show the final stage of bending in which one division body  5  is bent to an upright state in which the division body  7  is substantially orthogonal to the division body  5 , and the resin body  2  becomes an L shape. In the final stage of bending, a state in which the first inclined surface  35  of the lock projection  14  in the lock arm  12  is aligned with the second inclined surface  39  of the protrusion  18  of the side of the other division body  7  is obtained. Similarly, a state in which the first inclined surface  25  of the lock projection  13  in the lock arm  11  is aligned with the second inclined surface of the protrusion  17  of the other division body  7  is obtained. In this state, interference between the interference parts  22 ,  23 ,  32 ,  33  of the lock projections  13 ,  14  and the interference parts  37 ,  38  of the protrusions  17 ,  18  is eliminated, so that the lock arms  11 ,  12  are returned to the original position. 
         [0054]    The first inclined surfaces of the lock projections  13 ,  14  are aligned with the second inclined surfaces of the protrusions  17 ,  18  in the side wall parts of both sides of the division bodies  5 ,  7 . As a result of this, the two division bodies  5 ,  7  are engaged in both ends of the width direction, and a bent state can surely be locked. 
         [0055]    Also, as shown in  FIG. 11 , in this embodiment, the first inclined surfaces  25 ,  35  of the lock projections  13 ,  14  and the second inclined surfaces  39  of the protrusions  17 ,  18  are formed along the direction intersecting with respect to the reaction force by springback of the fuse element based on bending of the division bodies  5 ,  7 , so that in a state of alignment between the first inclined surfaces  25 ,  35  and the second inclined surfaces  39  in a state in which the first inclined surface  25  is mutually in surface contact with one second inclined surface  39  and the first inclined surface  35  is mutually in surface contact with the other second inclined surface  39 , these surfaces can surely be subjected to the reaction force F by springback. Therefore, the bent state can surely be fixed. 
         [0056]    In this embodiment as described above, it can surely be subjected to a load of springback from the fuse element, so that the bent state of the division bodies  5 ,  7  can be held and damage to the resin body  2  can be prevented. 
         [0057]    Further, in this embodiment, an extension line of alignment between the first inclined surfaces  25 ,  35  of the lock projections  13 ,  14  and the second inclined surfaces  39  of the protrusions  17 ,  18  matches with the center of bending of the division bodies  5 ,  7  which is the hinge part  3  as shown in  FIG. 8C . As a result of this, it can surely be subjected to the reaction force of springback of the fuse element based on bending of the division bodies  5 ,  7 , and the bent state of the division bodies  5 ,  7  can be held more stably. 
         [0058]    The invention is not limited to the embodiment described above, and various modifications can be made. 
         [0059]    The embodiment described above is constructed so that the lock arms  11 ,  12  flex to the outsides of the side wall parts by giving flexibility to the lock arms  11 ,  12 , but is not limited to this, and flexibility may be given to the protrusions  17 ,  18  by disposing the protrusions  17 ,  18  of the other division body  7  through a slit with respect to a main body by disposing the protrusions  17 ,  18  in the top side of the arm part protruding from the division body  7 . In this case, the protrusions  17 ,  18  flex to the insides of the side wall parts and thereby an operation of bending the division bodies  5 ,  7  can be performed smoothly. 
         [0060]    Also, at least any of the interference parts  22 ,  23 ,  32 ,  33  of the lock projections  13 ,  14  and the interference parts  37 ,  38  of the protrusions  17 ,  18  may be omitted. 
         [0061]    Further, it is unnecessary to set bending of the division bodies in the L shape, and it can also be applied to the fuse unit with a structure of stopping the bending before the L shape is formed. 
         [0062]    The present application is based on Japanese Patent Application No. 2009-230528 filed on Oct. 2, 2009, the contents of which are incorporated herein for reference. 
       INDUSTRIAL APPLICABILITY 
       [0063]    The present application is extremely useful in forming the fuse unit capable of being surely subjected to the load of springback from the built-in fuse element and holding the bent state of division bodies and preventing damage. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           1  fuse unit 
           2  resin body 
           3  hinge part 
           5  one division body 
           7  the other division body 
           11 ,  12  lock arm 
           13 ,  14  lock projection 
           17 ,  18  protrusion 
           21 ,  31 ,  36  slide surface part 
           22 ,  23 ,  32 ,  33 ,  37 ,  38  interference part 
           25 ,  35  first inclined surface 
           39  second inclined surface 
           51 ,  71  opposed wall part 
           52 ,  53 ,  72 ,  73  side wall part