Patent Publication Number: US-7717720-B2

Title: Electric connection box

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an electric connection box for preventing wear of heavy electric component terminals, such as a relay, and busbar terminals and trunk terminals in the electric connection box, due to movement of the electric component with vibration. 
   2. Description of the Related Art 
     FIG. 7  shows an embodiment of a conventional electric connection box (JP, 2000-331759,A). 
   The electric connection box  71  includes a relay  72 , as an electric component, having relay male terminals  73 , conductive trunk terminals  76  disposed between an upper cover  74  and a lower cover  75 , and busbar boards  77  having busbars  78  with busbar male terminals  79 . The relay male terminals  73  are connected with the busbar male terminals  79  through the trunk terminals  76 . 
   The relay  72  turns on and off a main circuit with excitation of a coil in the relay against the busbars  78 . The busbars  78  are strip-shaped conductive circuit bodies and have the busbar male terminals  79 , which are formed by bending vertically end portions of the busbars  78 . The upper cover  74  has a relay attachment portion  80  and a trunk terminal receiving room  81 . A lower face of the relay  72  abuts to an upper face of the relay attachment portion  80 . The lower cover  75  is fixed to the upper cover  74  and receives a plurality of the busbar boards  77  which are laminated each other. 
   Each busbar board  77  has the plurality of the busbars  78  separated by insulation substrates made of a synthetic resin. The trunk terminals  76  each have a pair of resilient contact pieces at an upper and lower portion of the vertical substrate. The relay male terminals  73  and busbar male terminals  79  are inserted between the substrate and the resilient contact pieces. 
     FIGS. 8 and 9  show another embodiment of a conventional electric connection box. 
   An electric connection box  82  includes an upper cover  83 , a lower cover  3 , guide walls  51 , and flexible locking frames  53 , which extend outwardly from the upper cover  83 . The guide walls  51  have an L-shape and are arranged to be fitted with corners of the relay  6 . The lower portions of the four corners of the relay  6  are guided by the guide walls  51  and locking protrusions  27  of the relay  6  are engaged with the locking frames  53 . The relay  6  is usually for a high current and high voltage use. 
   The upper cover  83  and lower cover  3  are fitted together with flexible side locking frames  10  and side locking protrusions  11 . The lower cover  3  has brackets  85  for fixing the lower cover  3  to a vehicle body. A middle plate  47  made of a synthetic resin is disposed above the lower cover  3 . The busbars  86  are arranged on the middle plate  47  and between the middle plate  47  and the lower cover  3 . Busbar male terminals  49  upstanding from the busbars  86  are connected to the relay male terminals  30  through the trunk terminals  48 . 
   The trunk terminals  48  have resilient contact pieces  63  at middle portions thereof and contact walls  68 ,  69  opposed to the resilient contact pieces  63 . The busbar male terminals  49  and relay male terminals  30  are connected together through the common resilient contact pieces  63 . 
   In the conventional electric connection box  82  of  FIGS. 8 and 9 , as shown in  FIG. 10 , spaces S 3  and S 4  are formed in respective directions of X and Y between the guide walls  51  and the relay  6  when the relay  6  is attached to the relay attachment portion  84 . Vibration of a vehicle at running or stopping moves the heavy relay  6  in the directions of X and Y, back and forth and leftward and rightward. This movement causes wears of the relay male terminals  30  and trunk terminals  48  and bends the resilient contact pieces  63  of the trunk terminals  48 . As a result of that, the contact pressure between the relay male terminals  30  and the busbar male terminals  49  is reduced. 
   As shown in  FIG. 11 , the guide walls  51  are tapered for easy molding. An upper space S 5  is larger than a lower space S 6 . Accordingly, the relay  6  swings inside the guide walls  51  in a direction of C and the relay male terminals  30  swing in a direction D. This movement accelerates the wear of the relay male terminals  30  and the trunk terminals  48  and the bending of the resilient contact pieces  63 . 
   As shown in  FIG. 9 , there are other spaces S 2  and S 7  in a direction of Z for locking between the locking protrusions  27  and the locking frames  53  and between the side locking frames  10  and the side locking protrusions  11 . An upper wall of the upper cover  83  is deformed with the weight of the relay  6  or the depression force of attachment of the relay  6 . The spaces S 2 , S 7  and the deformation of the upper cover  83  change a distance of H 2  between an upper face of the lower cover  3 , which contacts with the busbars, and a lower face of the relay  6  and a distance of H 3  between an upper face of the middle plate  47 , which contacts with the busbars, and the lower face of the relay  6 . The large changes of H 2  and H 3  cause the wear of the relay male terminals  30 , trunk terminals  48  and busbar male terminals  49 . 
   When a large and heavy fusible link is utilized instead of the relay  6  and the relay male terminals  30  are directly connected to the busbar male terminals  86 , not shown, without the trunk terminals  48 , the same problems, such as the wear and bending, occur. 
   SUMMARY OF THE INVENTION 
   The present invention is to provide an electric connection box for preventing movement of an electric component such as a large size relay and bending of a main body thereof and ensuring a reliable electric connection between the electric component and mating terminals. 
   According to a first aspect of the present invention, an electric connection box includes a main body, a guide wall disposed on the main body for retaining an electric component, a protrusion disposed on an inner face of the guide wall for preventing movement of the electric component. 
   Preferably, the guide wall has an upper protrusion at an upper end portion thereof and a lower protrusion at a lower end portion thereof, and the upper protrusion extends toward the electric component more than the lower protrusion and contacts with or approaches to the electric component. 
   Preferably, the guide wall has flexibility and the protrusion contacts with the electric component with the guide wall being bent outwardly. 
   Preferably, the guide wall is higher than the center of gravity of the electric component and the protrusion is positioned above the center of gravity of the electric component. 
   According to a second aspect of the present invention, an electric connection box includes a first cover for retaining an electric component, and a second cover having a locking member, wherein the locking member extends vertically and passes through the first cover for locking the electric component. 
   Preferably, the second cover has a middle plate for arrangement of a busbar and said locking member extends vertically through the middle plate. 
   According to a third aspect of the present invention, an electric connection box includes: a main body having a first cover and a second cover; a guide wall disposed on the first cover for retaining an electric component; a protrusion disposed on an inner face of the guide wall for preventing movement of the electric component; and a second cover having a locking member, wherein the locking member extends vertically and passes through the first cover for locking the electric component. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded perspective view of a first embodiment of an electric connection box of the present invention; 
       FIG. 2  is a sectional view of  FIG. 1  taken along a line  2 - 2  of a main body retaining a relay; 
       FIG. 3  is an essential plan view of the main body retaining the relay; 
       FIG. 4  is an essential plan view of a relay attachment portion of an electric connection box; 
       FIG. 5  is an exploded perspective view of a second embodiment of an electric connection box of the present invention; 
       FIG. 6  is an essential sectional view of the electric connection box retaining a relay; 
       FIG. 7  is a sectional view of a conventional electric connection box; 
       FIG. 8  is an exploded perspective view of another conventional electric connection box; 
       FIG. 9  is a vertical sectional view of the conventional electric connection box retaining a relay of  FIG. 8 ; 
       FIG. 10  is a plan view of a relay attachment portion of the conventional electric connection box of  FIG. 8 ; and 
       FIG. 11  is a sectional view taken along a line  11 - 11  of  FIG. 10 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1-3  show an embodiment of an electric connection box of the present invention. 
   An electric connection box  1  includes a main body  4  and a relay attachment portion  5  (electric component attachment portion), which is made of a synthetic resin, disposed on the main body  4  for retaining a large size relay (electric component)  6 , wherein the relay attachment portion  5  has guide walls  7 , which have an L-shape and extend above the center of gravity of the relay  6 . The guide walls  7  have upper protrusions  8  at upper end portions and lower protrusions  9  at lower end portions for preventing movement of the relay  6  and the upper protrusions  8  extend further toward the relay  6  more than the lower protrusions  9  extend. 
   Since the majority of the components associated with the present invention is similar to those of the conventional electric connection boxes of  FIGS. 8-9 , like reference numerals are used for identification thereof. The embodiment of the present invention is to provide the electric connection box for preventing lateral movements (X and Y directions) of the relay  6 . 
   The main body  4  has an upper cover  2  and a lower cover (base)  3 . Both covers  2  and  3  are locked to each other with side locking frames  10  and side locking protrusions  11 . Each guide wall  7  has side walls  12 ,  13  intersecting each other at a crossover portion  15  of the guide wall  7  and a height H 1  of the guide wall  7  is higher than the center of gravity m of the relay  6  as shown in  FIG. 2 . As shown in  FIG. 3 , the guide walls  7  face to vertical edges  14  of the relay  6 . The upper protrusions  8  are disposed at the upper end portions of the guide walls  7  and are opposed to each other about the crossover portion  15  and the lower protrusions  9  are disposed at the lower portions of the crossover portions  15 . 
   As shown in  FIGS. 1 and 2 , the upper protrusions  8  extend horizontally longer than the lower protrusions  9  from inner faces  18  of the guide walls  7 . As shown in  FIGS. 2 and 3 , the upper protrusions  8  contact with outer walls  16  of the relay  6  without a space and the lower protrusions  9  have a space S 1  against the outer walls  16  of the relay  6 . The guide walls  7  have a short width and a long height so that the guide walls  7  have flexibility in a direction of a thickness thereof and the upper protrusions  8  resiliently contact with the outer walls  16  of the relay  6  with the guide walls  7  being outwardly bent as shown in  FIG. 2 . In  FIG. 2 , dashed lines shown between the guide walls  7  and the outer walls  16  of the relay  6  indicate the disposition of the guide walls  7  when not outwardly bent, that is as the guide walls  7  would be disposed prior to placing the relay into the electric connection box which causes the guide walls  7  to bend outwardly. 
   Lower portions of the guide walls  7  do not bend, or bend very small, and the spaces S 1  are retained so that the relay  6  can be inserted assuredly into the guide walls  7  until the relay  6  abuts to an upper face  17  of the upper cover  2 . When the relay  6  moves in the direction C as shown in  FIG. 11 , the outer walls  16  of the relay  6  contact with the lower protrusions  9  and the movement of the relay  6  is suppressed. 
   Outer faces  8   a  of the upper protrusions  8  may be aligned vertically with outer faces  9   a  of the lower protrusions  9  so that both protrusions  8  and  9  contact with the outer walls  16  of the relay  6  with the same contact pressure. As shown in  FIG. 1 , the lower protrusions  9  are disposed between the upper protrusions  8  so that die cutting is easily made. 
   The upper protrusions  8  are arranged at each side of the guide walls  7  so that the guide walls  7  stably retain the relay  16  with respect to directions of X and Y. The guide walls  7  each have the two upper protrusions  8  and one lower protrusion  9  for retaining the relay  6  with three-point mounting. 
   As shown in  FIG. 2 , the upper protrusions  8  are positioned above the center of gravity m of the relay  6  and retain the relay  6  above the center of gravity m thereof so that the movement of the heavy relay  6  in the X and Y, or lateral directions is assuredly prevented with the upper protrusions  8 . Accordingly, wears of relay terminals  30 , trunk terminals and busbar terminals due to the small movement are prevented and a deformation of resilient contact pieces of the trunk terminals is avoided. 
   The upper protrusions  8  at least contact with the outer walls  16  of the relay  6  so that, even when the guide walls  7  have a draft angle similarly to the conventional electric connection box as shown in  FIG. 11 , the movement of the relay  6  and the wear of all terminals are prevented. 
   The upper and lower protrusions  8  and  9  each have slopes  8   b  and  9   b  at the upper faces of the respective protrusions  8  and  9 . The slopes  8   b  and  9   b  guide the relay  6  when the relay  6  is inserted into the guide walls  7 . As shown in  FIG. 2 , lower faces  8   c  of the upper protrusions  8  and lower faces  9   c  of the lower protrusions  9  are perpendicular to the inner faces  18  of the guide walls  7 . The lower protrusions  9  may be vertically connected to the upper face  17  of the upper cover  2 . 
   Die cutting through holes  21  are disposed at the upper face  17  in vicinities of bottoms of the guide walls  7  for bending further the guide walls  7  so as that the upper protrusions  8  more assuredly abut to the relay  6 . The lower protrusions  9  are disposed at the intersection of side walls  12 ,  13  of the guide walls  7  and have an L shape in a plan view. 
   As shown in  FIG. 3 , spaces  22  and  23  are disposed between the guide walls  7 . The spaces  22  extending along the longitudinal direction of the relay  6  are utilized for attaching and detaching the relay with hand. Locking frames  24  extend vertically from the upper face  17  of the upper cover  2  and inner faces  25  thereof are about flush with the lower protrusions  9 . 
   The guide walls  7  are higher than the locking frames  24  and the upper protrusions  8  are located above the locking frames  24 . Each locking frame  24  has a pair of supporting pieces  28 , a connecting piece  29  and a through hole  26 . Locking protrusions  27  of the relay  6  engage with the through holes  26 . When engaging, the locking frames  24  bend outwardly and return after engaging. 
   A middle plate and busbars (not shown) are disposed inside the main body  4  of the electric connection box  1  similarly to the conventional box as shown in  FIG. 9 . As shown in  FIG. 1 , through holes  31  for insertion of the relay male terminals  30  are disposed on the upper walls  17  of the upper cover  2  and inside the guide walls  7 . The relay male terminals  30  are connected to the busbar male terminals (not shown) through the trunk terminals (not shown). 
   The relay male terminals  30  can be connected directly to the busbar male terminals without the trunk terminals. Relay female terminals (not shown) can be connected to the busbar male terminals. 
     FIG. 4  shows a modification of the guide walls  7  of the upper cover  2 . Detailed explanations are omitted for the like reference numerals of the embodiment of  FIG. 1 . 
   The spaces  22  are removed to form integral guide walls  7 ′. The upper protrusions  8  are disposed at middle portions of the walls  7 ′. 
   The another upper protrusions  8  of each guide wall  7 ′ are kept at end portions of walls  12 , namely close to the locking frames  24 . The lower protrusions  9  of the guide walls  7 ′ are disposed facing to the vertical edges  14  of the relay  6 . The functions of the guide walls  7 ′ and the protrusions  8  and  9  are the same as those of the first embodiment. 
   In the embodiments of  FIGS. 1-4 , the relay  6  can be square shaped instead of a rectangle. In this case, both side walls  12  and  13  have the same width and the upper protrusions  8  are positioned symmetrical with respect to the intersection of the side walls  12  and  13 . This arrangement is also adapted to the rectangle shaped relay  6 . 
   Although the upper and lower protrusions  8  and  9  are disposed on the guide walls  7  to prevent the movement of the relay  6 , the upper protrusions  8  can only be disposed without the lower protrusions  9 . 
   In the above embodiments, the upper protrusions  8  may have a space against the relay  6 . It is preferable that the upper protrusions  8  extend toward the relay more than the lower protrusions  9 . 
   In the above embodiments, the guide walls  7  are higher than the center of gravity m of the relay  6 . The upper and lower protrusions  8  and  9  for preventing the movement of the relay  6  can be disposed at a height equal or below the center of gravity m of the relay  6 . In this case, the protrusions can be disposed only at the upper portion or at the upper and lower portions of the guide walls. 
   The guide walls  7  can be disposed facing to the outer walls  16  of the relay  6  and have opening portions in vicinities of the vertical edges  14  of the relay  6 . The upper and/or lower protrusions  8  an  9  can be disposed on all guide walls or main walls. 
     FIGS. 5 and 6  show a second embodiment of the electric connection box of the present invention. The explanation to the like reference numerals of the first embodiment is omitted. 
   An electric connection box  41  includes a main body  44  having an upper cover (first cover)  42  and a lower cover (second cover)  43 , a middle plate  47 , which is made of an insulation synthetic resin, disposed inside the main body  44 , conductive busbars  46  disposed along the middle plate  47  and the lower cover  43 , and a relay  6  attached to a relay attachment portion (electric component attachment portion)  45  and connected to vertical busbar male terminals  49  through trunk terminals  48 . Flexible locking frames (locking members)  53  to be engaged with locking protrusions  27  of the relay  6  are disposed on the lower cover  43  instead of the upper cover  42 . The locking frames  53  extend vertically from the lower cover  43  and pass through the middle plate  47  and the upper cover  42 . 
   The other structure of this embodiment is almost same as that of the conventional electric connection box of  FIGS. 8 and 9 . 
   As shown in  FIG. 5 , four guide walls  51  are upstanding on an upper face  17  of the upper cover  42 . Each guide wall  51  has side walls  54  and  55  which are intersecting to each other. A pair of through holes  52  are disposed on the upper face  17  surrounded by the guide walls  51  and the locking frames  53  extend vertically and pass through the through holes  52 . 
   In this embodiment, the protrusions  8  and  9  for preventing the movement of the relay  6  are not disposed in the guide walls  51  and the guide walls  51  are lower than the guide walls  7  of the first embodiment. The higher walls  51  and the attachment of the protrusions  8  and  9  are also effective and prevent the movement of the relay  6  in X, Y and Z directions. 
   Each long locking frame  53  has a pair of supporting pieces  56 , a connecting piece  57  connected to the each supporting piece  56 , and a through hole  58  surrounded by the supporting and connecting pieces  56  and  57 . As shown in  FIG. 6 , the supporting pieces  56  and the through hole  58  of the each locking frame  53  extend from the lower cover  43  and pass through the upper cover  42 . The through hole  58  communicates with an opening of the lower cover  43 . The locking frames  53  are formed integrally with the lower cover  43 . 
   Through holes  59  and  52  are formed in the middle plate  47  and the upper cover  42  for the locking frames  53  to be flexible in a direction of a thickness thereof over the entire length. Bosses  60  are disposed around the through holes  59  of the middle plate  47  and suppress bending of the locking frames  53 . 
   The through holes  59  of the middle plate  47  and through holes  53  of the upper cover  42  can be a narrow width so as to hold the long locking frames  53  without clearances. The through holes  52  of the upper cover  53  can be a supporting point for flexure of the locking frames  53 . The through holes  53  of the locking frames  53  can be formed only above the upper cover  42  for flexure of the locking frames  53  so as to suppress the flexure of the locking frames  53  and also the movement of the relay  6 . 
   The locking frames  53  can be replaced with flexible locking arms (not shown), which are disposed on the lower cover  43 . The locking arms have locking protrusions at tips thereof and the locking protrusions engage with upper faces of the locking protrusions  27  of the relay  6  or locking recesses (not shown) disposed on the outer walls  16  of the relay  6 . The locking frames  53  or locking arms can be disposed on the middle plate  47  instead of the lower cover  43 . 
   As shown in  FIG. 6 , when the locking frames  53  are disposed on the lower cover  43  for locking the relay  6 , a distance H 2  of between the lower face  19  of the relay  6  and the upper face  62  of the lower cover  43  only varies with a locking space S 2  of between the locking protrusions  27  of the relay  6  and the locking frames  53 . The movement of the relay  6  is not affected by locking spaces between the side locking frames  10  and side locking protrusions  11  and bending of the upper cover  42  due to the relay  6  depressed. Accordingly, the distance H 2 , or the vertical movement (Z direction) of the relay  6  is suppressed. Then, the wear of the relay male terminals  30  and the resilient contact pieces  63  at contact points  54  are reduced. The wear of the busbar male terminals  49  and resilient contact pieces  63  at contact points  65  are also reduced. When the locking spaces S 2  are set to nearly zero, the wear due to the vertical movement of the relay  6  is completely suppressed. 
   These effects are also achieved by the locking arms. When the locking frames  53  are disposed on the middle plate  47  instead of the lower cover  43 , since the distance H 2  varies due to the change of the locking spaces between the side locking means  10  and  11 , the effect of reducing the wear of the terminals decreases compared to the case of that the locking frames  53  are disposed on the lower cover  43 . There is no bending on the upper face  17  of the upper cover  42  due to the relay  6  depressed so that the wear protection is better than the conventional electric connection box. 
   As shown in  FIG. 6 , the busbars  46  have busbar male terminals  50  extending downwardly. The busbar male terminals  50  are positioned in connector housings integral with the lower cover  43  and form connectors  66 . Connectors of external wiring harnesses or electric components (not shown) are connected to the connectors  66 . 
   The upper face of the lower cover  43  contacts with the lower face of the middle plate  47 . The upper face of the middle plate contacts with lower ends of trunk terminal receiving walls  67  of the upper cover  42 . Each relay male terminal  30  is inserted into between the respective resilient contact piece  63  and a contact wall  68  of the trunk terminal  48 . Each busbar male terminal  49  is inserted into between the contact wall  69  and resilient contact piece  63 . Other busbars, not shown, are disposed between the lower cover  43  and the middle plate  47  or disposed on the upper face of the middle plate  47 . 
   The second embodiment of  FIGS. 5 and 6  can also be adapted to the first embodiment of  FIG. 1 to 4  so that the movement of the relay  6  toward the longitudinal and lateral directions are suppressed and the wears of the relay male terminals  30 , trunk terminals  48  and busbar male terminals  49  are prevented. 
   In the second embodiment, it is possible to dispose only the locking frames (locking member)  53  without the guide walls  51  similarly to the prior art of  FIG. 7 . 
   The locking means between the upper cover  42  and the lower cover  43  of the first and second embodiments are not limited to the exemplary cases of  FIGS. 1 and 5  and can be modified in any means. 
   The operating effects described above are also pertinent to the electric connection boxes when they are disposed vertically or obliquely. In this case, the lateral and longitudinal directions correspond to the vertical and horizontal directions, respectively.