Abstract:
To provide an electrical junction box having a new structure that can be securely attached to a hole and can be readily removed even if a large clearance is required between the electrical junction box and a peripheral edge section around the attachment hole. An elastic projecting piece is integrally provided on a main body of an electrical junction box. The elastic projecting piece protrudes from an outer surface of the main body. The elastic projecting piece is provided with an engagement projection and an attachment projection that protrude outward from the main body opposite from each other in an extending direction of the elastic projecting piece to constitute an engagement fixing section. Elastic deformation of the elastic projecting piece permits the main body to be fitted into the attachment hole. A second inner peripheral edge portion around the attachment hole is clamped between the engagement and attachment projections.

Description:
INCORPORATION BY REFERENCE 
       [0001]    This application claims priority to JP 2009-156377 filed in Japan on Jun. 30, 2009, the disclosure of which is hereby incorporated by reference in its entirety. 
       BACKGROUND 
       [0002]    In accordance with an aspect of the exemplary embodiments, the embodiments relate to an electrical junction box to be mounted on a motor vehicle or the like and more particularly relates to an electrical junction box to be fitted into an attachment hole in a vehicle body panel to be mounted on a vehicle body. 
         [0003]    Electrical equipment in a motor vehicle is generally contained within a box such as a fuse box, a junction box, or a connector holder. The electrical junction box is generally attached to a vehicle body panel in a vehicle room or an engine room. There is an electrical junction box in which a protruding amount into the vehicle room or the like is reduced by merely fitting the box into an attachment hole in the vehicle body panel when the box is mounted on the vehicle body panel. 
         [0004]    Such electrical junction box has been disclosed in JP HEI 11(1999)-238557 A (Patent Document 1). The electrical junction box is generally provided with an engagement fixing section to be secured to an opening peripheral edge section around the attachment hole in the vehicle body panel. The electrical junction box can be secured to the vehicle body panel by merely fitting the engagement fixing section into the attachment hole. Such engagement fixing section includes a flange portion to be superimposed on a front side surface on a whole opening peripheral edge section around the attachment hole in the vehicle body panel, and a plurality of engagement pawls to be locked on a rear side surface on the opening peripheral edge section around the attachment hole in the vehicle body panel. When the electrical junction box is fitted into the attachment hole, the engagement pawls are elastically deformed to turn to the rear side of the vehicle body panel and the vehicle body panel is clamped between the engagement pawls and the flange portion. As a result, the electrical junction box is secured to the vehicle body panel. 
         [0005]    When the electrical junction box is fitted into the attachment hole in the vehicle body panel, clearance should be left between the opening peripheral edge section around the attachment hole and the electrical junction box. Such clearance can be used to pass a cable through the vehicle body panel so as to arrange the cable in the vehicle body or it can be used as a service hole for maintenance. 
         [0006]    However, in an attachment structure of the conventional electrical junction box as disclosed in Patent Document 1, there is a problem that it is difficult to provide a large clearance between an outer peripheral surface of the electrical junction box and the opening peripheral edge section around the attachment hole. That is, in order to form a large clearance, not only the flange portion to be provided on the outer peripheral surface of the electrical junction box must be extended greatly on the outer peripheral surface, but also the flange portion must be separated on the outer peripheral surface. This will cause a problem that strength of the flange portion itself and fixing strength of the flange portion onto the vehicle body panel are greatly reduced. 
         [0007]    In addition, in the attachment structure of the electrical junction box disclosed in Patent Document 1, when the electrical junction box is removed from the vehicle body panel after mounting, there is a problem that it is difficult to release engagement pawls from a rear side surface of the vehicle body panel. That is, in order to release the engagement pawls from a front side of the vehicle body panel, it is generally necessary to provide the flange portion with a working hole for passing a tool such as a lever. This will cause a problem that a mold for the electrical junction box becomes complicated and a releasing work is troublesome since the tool must be inserted into a small hole to release the engagement pawls. 
       SUMMARY 
       [0008]    In accordance with an aspect of the exemplary embodiments, it may be advantageous to address or overcome the problems discussed above by providing an electrical junction box having a new structure that can be strongly secured to an attachment hole and can be readily removed from the attachment hole even if a large clearance is required between an outer surface of the electrical junction box and an opening peripheral edge section around the attachment hole. 
         [0009]    One preferred embodiment is directed to an electrical junction box including a main body and an engagement fixing section provided on the main body. The main body is fitted into an attachment hole in a vehicle body panel of a motor vehicle. The engagement fixing section is secured to the vehicle body panel. An elastic projecting piece is provided on the main body. The elastic projecting piece protrudes from an outer surface of the main body toward the attachment hole. The elastic projecting piece can be provided with an engagement projection and an attachment projection that protrude outward from the main body beyond the distal end of the projecting piece. The engagement and attachment projections are positioned opposite to each other at a distance corresponding to the thickness of the wall in which the attachment hole is located. The engagement and attachment projections constitute the engagement fixing section. Elastic deformation of the elastic projecting piece permits the main body to be fitted into the attachment hole. An inner peripheral edge section around the attachment hole is clamped between the engagement and attachment projections. 
         [0010]    In accordance with a preferred embodiment, the engagement and attachment projections that clamp the vehicle body panel are provided on the elastic projecting piece that protrudes from the main body of the electrical junction box. Thus, even if a large clearance is defined between the main body and the inner peripheral edge section around the attachment hole, the engagement and attachment projections can clamp the inner peripheral edge section around the attachment hole separated apart from the main body, thereby firmly and strongly securing the main body to the attachment hole. Because the clearance between the main body and the inner peripheral edge portion is not closed, it is possible to attach the electrical junction box to the vehicle body panel while sufficiently holding arrangement of cables, maintenance, and the like. 
         [0011]    Further, because it is possible for the main body to be fitted into and removed from the attachment hole by elastically deforming the elastic projecting piece, it is also possible for the electrical junction box to be mounted onto and removed from the vehicle body panel. Particularly, when the electrical junction box is removed from the vehicle body panel, it is possible to readily remove the electrical junction box from the front side of the vehicle body panel by operating the projecting portion of the elastic projecting piece that protrudes from the front side surface of the vehicle body panel without resorting to using a tool on the rear side of the vehicle body panel. 
         [0012]    Also, the preferred embodiments can preferably adopt a structure wherein the attachment projection is disposed outside the engagement projection in the extending direction of the elastic projection piece, and a projecting height of the attachment projection is set to be greater than that of the engagement projection. 
         [0013]    According to the this structure, it is possible to contact the attachment projection with the front side surface of the vehicle body panel more positively to engage the attachment projection with the front side surface while permitting the engagement projection to turn to the rear side of the vehicle body panel. Thus, it is possible to more positively prevent the elastic projecting piece from disconnecting from the vehicle body panel. 
         [0014]    The preferred embodiments can preferably adopt a structure wherein the elastic projecting piece is provided on a distal end with an elastic deformation operating portion that elastically deforms the elastic projecting piece toward the main body in a releasing direction of the elastic projecting piece. According to the this structure, because the elastic deformation operating portion is disposed on the elastic projecting piece at the distal end, i.e., the most remote position from the proximal end that serves as a base point of elastic deformation, it is possible for a small force to readily release the elastic projecting piece from the inner peripheral edge section around the attachment hole by merely pushing the elastic deformation operating portion by a finger. 
         [0015]    The preferred embodiments can preferably adopt a structure wherein the main body is provided with a base projection that protrudes from an outer peripheral surface of the main body, and the elastic projecting piece protrudes further outward from the base projection. According to this structure, it should be possible to restrain a stress concentrated in the proximal end of the elastic projecting piece upon elastic deformation and to enhance strength of the wall of the main body. 
         [0016]    In accordance with the preferred embodiment, because the engagement and attachment projections are provided on the distal end of the elastic projecting piece that protrudes from the main body of the electrical junction box, the engagement and attachment projections can clamp the inner peripheral edge section around the attachment hole separated apart from the main body, thereby positively and strongly securing the electrical junction box to the vehicle body panel, even if a clearance is defined between the main body and the inner peripheral edge section around the attachment hole. Accordingly, the engagement and attachment projections should be spaced apart by a distance that corresponds to the thickness of the wall in which the attachment hole is located. Further, it is possible to release the elastic projecting piece from the inner peripheral edge section around the attachment hole by operating the projecting portion of the elastic projecting piece that protrudes from the vehicle body panel, thereby readily removing the electrical junction box from the front side surface of the vehicle body panel. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a perspective view of an embodiment of a connector holder in accordance with the present invention and an enlarged perspective view of a main part of the connector holder. 
           [0018]      FIG. 2  is a top plan view of the connector holder shown in  FIG. 1 . 
           [0019]      FIG. 3  is a front elevation view of the connector holder shown in  FIG. 1 . 
           [0020]      FIG. 4  is a perspective view of the connector holder shown in  FIG. 1 , illustrating the connector holder attached to a vehicle body panel. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0021]    Referring now to the drawings, embodiments of an electrical junction box in accordance with an exemplary preferred embodiment will be described below in detail to clarify various aspects of the preferred embodiment. 
         [0022]      FIGS. 1 to 3  show an embodiment of a connector holder  10  that is an example of an electrical junction box in accordance with an exemplary preferred embodiment. The connector holder  10  is a molded product made of a material such as synthetic resin. The connector holder  10  includes a main body  12  that serves as a main body of the electrical junction box. The main body  12  is substantially formed into a rectangular box-like configuration that is open at upper and lower sides (upper and lower sides in  FIG. 3 ). This main body  12  constitutes a connector containing section. As shown in  FIG. 2 , a connector  13  can be contained and fixed in the main body  12  in an engagement manner or a fitting manner utilizing a lever. 
         [0023]    The connector holder  10  can be inserted into and engaged with a hole  56  in a vehicle body panel  54  (mentioned after by referring to  FIG. 4 ). Hereinafter, a lower side in  FIG. 2  with respect to a fitting direction of the connector holder  10  designates a front side (front surface) of the connector holder  10  (main body  12 ) while an upper side in  FIG. 2  with respect to the fitting direction designates a rear side (rear surface) of the connector holder  10  (main body  12 ). Upper and lower directions in  FIG. 3  designate upper and lower directions of the connector holder  10  (main body  12 ). 
         [0024]    A side wall  14  of the main body  12  is integrally provided on an outer peripheral surface with a base projection  16  that protrudes outward from the side wall  14 . The base projection  16  is substantially formed into a rectangular block-like configuration. The base projection  16  is provided on a projecting end surface at the front side of the main body  12  with an escape surface  18  that gradually approaches the side wall  14  toward the front side. 
         [0025]    Further, the base projection  16  is integrally provided on a rear edge part at the rear side of the main body  12  with an elastic projecting piece  20 . The elastic projecting piece  20  is substantially formed into an L-shaped plate-like configuration. The elastic projecting piece  20  includes an outward extending portion  22  that protrudes outward from the projecting edge portion of the base projection  16  at the rear side of the main body  12  and a forward extending portion  24  that extends forward from an extending end portion of the outward extending portion  22  substantially in parallel with the side wall  14  of the main body  12 . The outward extending portion  22  and forward extending portion  24  are interconnected through a curved portion  26  to each other. The forward extending portion  24  extends from a side of the curved portion  26 , which is a proximal end side in an extending direction, to the front side of the main body  12 , which is a distal end side in the extending direction, so that the forward extending portion  24  inclines slightly outward. 
         [0026]    The elastic projecting piece  20  has a substantially constant width in the upper and lower directions. The width of the piece  20  is substantially the same as a width of the base projection  16  in the upper and lower directions. An outer surface of the curved portion  26  is formed into a smooth curved surface from the outward extending portion  22  to a slant guide inner surface  34  (mentioned after) of the forward extending portion  24  so as to avoid concentration of stress upon elastic deformation and so as to obtain sufficient strength. Further, the outward extending portion  22  is provided on an inner surface at a central part in the upper and lower directions with a reinforcement rib  28 . 
         [0027]    The forward extending portion  24  is integrally provided with an engagement projection  30  and an attachment projection  32  that protrude outward in a direction departing apart from the outer side surface of the main body  12 . The engagement projection  30  and attachment projection  32  constitute an engagement fixing section. 
         [0028]    The engagement projection  30  on the forward extending portion  24  is substantially formed into a right triangle block in plan view. The right triangle block is disposed at the rear side (at an upper side in  FIG. 2 ) of the main body  12  and at a proximal end side in the extending direction. A slant portion of the engagement projection  30  is formed into a slant guide surface  34  that gradually protrudes outward from the curved portion  26  on the forward extending portion  24  to a distal end side in an extending direction. The slant portion of the engagement projection  30  is partially cut off and is provided with a slant surface  36  that extends along an inner peripheral surface on the attachment hole  56  in the vehicle body panel  54  mentioned after. The right triangle engagement projection  30  is provided on a base side with an engagement surface  38  that substantially stands upward vertically from the forward extending portion  24 . 
         [0029]    On the other hand, the attachment projection  32  on the forward extending portion  24  is disposed at the front side (at a lower side in  FIG. 2 ) of the main body  12  and at a distal end side in the extending direction. The attachment projection  32  is formed into a projecting piece configuration that protrudes outward vertically to extend in a direction departing apart from the main body  12 . The attachment projection  32  is provided on a rear side with a superimposing surface  40  that stands upward vertically from the forward extending portion  24 . 
         [0030]    The engagement projection  30  and attachment projection  32  are opposed to and separated from each other by a given distance in the extending direction of the forward extending portion  24 . The attachment projection  32  is disposed at the distal end side than the engagement projection  30  in the extending direction of the forward extending portion  24 . Thus, the engagement surface  38  and superimposing surface  40  are separated apart from each other by a given distance and are opposed in parallel with each other. A distance between the engagement surface  38  and the superimposing surface  40  is set to be equal to or slightly greater than a dimension in thickness of the inner peripheral surface around the attachment hole  56  in the vehicle body panel  54  mentioned after. An outer surface  42  on the forward projecting portion  24  disposed between the engagement surface  38  and the superimposing surface  40  is inclined to extend along the inner peripheral surface around the attachment hole  56  in the vehicle body panel  54 , thereby enhancing stability of attachment to the vehicle body panel  54 . 
         [0031]    A projecting dimension of the attachment projection  32  from the forward projecting portion  24  is set to be greater than that of the engagement projection  30 . Thus, the superimposing surface  40  is extruded outward from the main body  12  than the engagement surface  38 . The superimposing surface  40  has an area greater than the engagement surface  38 . 
         [0032]    Further, the elastic projecting piece  20  is integrally provided on a distal end side in the extending direction at a front side of the main body  12  with an elastic deformation operating portion  44  that protrudes further forward from the attachment projection  32 . When the elastic deformation operating portion  44  is pushed by a finger, the elastic projecting piece  20  can be elastically deformed toward the main body  12 . Particularly, in the present embodiment, the elastic deformation operating portion  44  is integrally provided on an upper end edge portion with a triangular plate-like reinforcement wall  46  that protrudes outward from the main body  12  to be connected to the attachment projection  32 , thereby enhancing strength of the operating portion  44 . The elastic deformation operating portion  44  holds the finger to facilitate an operation of the elastic projecting piece  20 . 
         [0033]    Also, the main body  12  is integrally provided on a side wall  48  at a side opposite from the elastic projecting piece  20  with a flange-like attachment plate portion  50 . The attachment plate portion  50  protrudes downward at the front side end of the main body  12 . A projecting end of the attachment plate portion  50  is provided with a bolt passing hole  52 . The distance between the side wall  48  and the outer surface  42  located on the distal end of the elastic projecting piece  20  should preferably be dimensioned so as to correspond to the width of the attachment hole  56 . Based on this configuration, the main body  12  can be held firmly within the attachment hole  56  by the slight biasing of the elastic projection piece  20  against an edge of the attachment hole  56  as well as by the clamping of the wall of the vehicle body  54  between the engagement projection  30  and the attachment projection  32 . See, for example,  FIG. 4 . 
         [0034]    After the main body  12  contains the connector  13  or the like, the connector holder  10  constructed above is inserted into and secured to the attachment hole  56  in the vehicle body panel  54 . The attachment hole  56  penetrates the vehicle body panel  54  in its thickness direction so that a wire harness, a tool, or the like can be inserted into the hole  56 . The attachment hole  56  is preferably formed into a square shape with round corners (see  FIG. 4 ) and an opening dimension is set to be greater than the main body  12 . A first inner peripheral edge portion  58   a  defines one side of an inner peripheral edge section  58  around the attachment hole  56  and preferably extends straightly along the side wall  48  provided with the attachment plate  50  on the main body  12 . A second inner peripheral edge portion  58   b  is located opposite to the first inner peripheral edge portion  58   a  and is preferably slanted with respect to the first inner peripheral edge portion  58   a.    
         [0035]    In order to attach the connector holder  10  to the vehicle body panel  54 , the rear side part of the connector holder  10  is inserted into the attachment hole  56  from a front surface  60  of the vehicle body panel  54  along an insertion direction to a rear side of the vehicle body panel  54 . The main body  12  is inserted into the attachment hole  56  so that the side wall  48  provided with the attachment plate portion  50  contacts the first inner peripheral edge portion  58   a  and the elastic projecting piece  20  is directed to the second inner peripheral edge portion  58   b.  When the connector holder  10  is inserted into the attachment hole  56 , the elastic deformation operating portion  44  may be pushed to the main body  12  by a finger and the elastic projecting piece  20  may be elastically deformed toward the main body  12 . However, in the present embodiment, because the slant guide surface  34  is provided on the proximal end of the elastic projecting piece  20  at the rear side of the main body  12 , the main body  12  may be inserted into the attachment hole  56  and the elastic projecting piece  20  may be elastically deformed by a guiding action of the slant guide surface  34  and second inner peripheral portion  58   b.  Because the escape surface  18  is provided on the projecting end of the base projection  16 , the elastic deformation of the elastic projecting piece  20  is not interfered with the base projection  16 . 
         [0036]    When the elastic projecting piece  20  is inserted into the attachment hole  56 , the elastic projecting piece  20  elastically bends at the curved portion  26  towards the main body  12 , and the engagement projection  30  passes behind the vehicle body panel  54  while the attachment projection  32  engages with the front side surface  60  of the vehicle body panel  54 . Thus, as shown in  FIG. 4 , the second inner peripheral edge surface  58   b  around the attachment hole  56  is clamped between the engagement projection  30  and the attachment projection  32 . The engagement surface  38  of the engagement projection  30  is engaged with the rear side of the vehicle body panel  54 . The elastic projecting piece  20  is secured to the vehicle body panel  54 . The attachment plate portion  50  is superposed on the front side surface  60  of the vehicle body panel  54  and is secured to the vehicle body panel  54  by a bolt passing through the bolt through-hole  52 . Thus, the main body  12  is fitted into the attachment hole  56  and secured to the vehicle body panel  54 . 
         [0037]    When the connector holder  10  is inserted into the attachment hole  56 , the one side wall  48  of the main body  12  contacts the first inner peripheral edge portion  58   a  while the other side wall  14  is separated apart from the second inner peripheral edge portion  58   b.  To compensate for the distance between the side wall  14  and the peripheral edge portion  58   b,  the elastic projecting piece  20  protrudes outward from the side wall  14  towards the second inner peripheral edge portion  58   b,  and as a result, the portion  58   b  is clamped between the engagement projection  30  and the attachment projection  32 . Clearances  62  can be defined between the main body  12  and the second inner peripheral edge portion  58   b  at the upper and lower sides of the elastic projecting piece  20 . The clearances  62  can receive a wire harness, a tool, or the like. 
         [0038]    In the event that clearances  62  are defined between the main body  12  and the second inner peripheral edge portion  58   b  in the connector holder  10  constructed above, because the elastic projecting piece  20  extends from the main body  12  to the second inner peripheral edge portion  58   b  to be engaged with the portion  58   b,  the main body  12  can be inserted into the attachment hole  56  and can be secured to the vehicle body panel  54 . Particularly, because the vehicle body panel  54  is clamped between the engagement projection  30  and attachment projection  32  provided on the elastic projecting piece  20 , it is possible to strongly secure the elastic projecting piece  20  to the vehicle body panel  54 . Further, in the exemplary embodiment, because the height of the attachment projection  32  protruding outward from the forward extending portion  24  is set to be greater than a height of the engagement projection  30 , the attachment projection  32  cannot enter the attachment hole  56  by the elastic deformation of the elastic projecting piece  20  that enables the engagement projection  30  to enter the attachment hole  56 . In other words, attachment projection  32  and the engagement projection  30  extend in a projection direction toward the peripheral edge portion  58   b.  Because the attachment projection  32  extends in the projection direction further than the engagement projection  30 , deformation of the projecting piece  20  is sufficient to allow the engagement projection  30  to pass behind the peripheral edge portion  58   b,  while preventing the attachment projection  32  from passing through the attachment hole  56  and through the vehicle body panel  54 , thereby more positively clamping the vehicle body panel  54 . 
         [0039]    When the connector holder  10  is removed from the vehicle body panel  54 , the elastic deformation operating portion  44  that protrudes from the front side surface  60  of the vehicle body panel  54  is pushed by a finger toward the main body  12  to release engagement among the engagement projection  30 , the attachment projection  32 , and the vehicle body panel  54 . Then, it is possible to release the connector holder  10  from the front side of the vehicle body panel  54  without inserting a special tool into the rear side of the vehicle body panel  54 . Further, because the elastic deformation operating portion  44  on the elastic projecting piece  20  is disposed most apart from the curved portion  26 , it is possible to elastically deform the elastic projecting piece  20  with a minimal force. Because the projecting end surface of the engagement projection  30  is formed into the slant surface  36  that extends along the second inner peripheral edge portion  58   b  in the attachment hole  56 , it is possible to reduce the elastic deformation of the elastic projecting piece  20  required for drawing the engagement projection  30  from the attachment hole  56 , and it is possible to prevent the engagement projection  30  from interfering with the second inner peripheral edge portion  58   b,  thereby enabling more smooth disengagement of the engagement projection  30 . 
         [0040]    In addition, because the curved portion  26  is coupled through the base projection  16  to the side wall  14 , it is possible to reduce transmission of a stress concentrated in the curved portion  26  to the side wall  14 , thereby ensuring sufficient strength of the side wall  14 . Because the outward extending portion  22  of the elastic projecting piece  20  protrudes from the base projection  16  that protrudes outward from the side wall  14 , it is possible to reduce a projecting dimension of the outward extending portion  22  in comparison with the case where the outward extending portion  22  protrudes directly from the side wall  14 . Thus, because it is possible to mount the connector holder  10  in the attachment hole  56  by a greater fitting force than a long outward extending portion  22 , it is possible to ensure a high precise of a required fitting force. 
         [0041]    Because the connector holder  10  including the elastic projecting piece  20  are preferably molded out of a product such as synthetic resin, the construction of the connector holder  10  is simple and can ensure extremely high efficiency in cost. 
         [0042]    A flange-like attachment plate portion  50  that has been known conventionally as a bolt-fastening type is adopted in the outer surface  42  that contacts the first inner peripheral edge portion  58   a  in the attachment hole  56  together with the elastic projecting piece  20  in the above embodiment. This can obtain an excellent fitting force. However, it is possible to combine the elastic projecting piece of the present invention with the conventional known attachment structure. The conventional known attachment structure may include a pin-lock mechanism or the like as well as the bolt-fastening mechanism in the above embodiment, as required. 
         [0043]    It is possible to provide the main body of the electrical junction box with a plurality of elastic projecting pieces. For example, the whole outer peripheral surface of the main body of the electrical junction box may be separated apart from the inner peripheral edge section around the attachment hole, and the main body may be held in the attachment hole by the plural elastic projecting pieces. 
         [0044]    Although the connector holder is exemplified as an electrical junction box in the above embodiment, the present invention can be applied to a fuse box, a relay box, a junction box, or the like.