Abstract:
An electronic device storage case for use in storing a substrate therein, includes a hollow box-shaped case body. The case body includes an open surface with an opening, a bottom surface opposite to the opening and a sidewall extending upright from the peripheral edge of the bottom surface, wherein the sidewall of the case body including a plurality of deformable ribs each having a slant surface inclined inwards toward the bottom surface, and wherein the substrate is introduced into the case body through the opening and slidingly moves along the slant surface of each of the deformable ribs to make pressure contact with the slant surface.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to an electronic device storage case. 
       BACKGROUND OF THE INVENTION 
       [0002]    Conventionally, a motor vehicle is equipped with, e.g., an ECU (Engine Control Unit) in which a substrate is stored within an electronic device storage case. The electronic device storage case includes two members locked together by a male-female locking unit. 
         [0003]    The male-female locking unit of the electronic device storage case includes a locking projection portion protruding from one of the members and a locking hole portion formed on the surface of the other member facing the surface of one member on which the locking projection portion exists. The locking projection portion is inserted into and locked with the locking hole portion. 
         [0004]    In the electronic device storage case provided with the male-female locking unit, it is likely that a gap is left between the locking projection portion and the locking hole portion due to manufacturing errors or other causes. If the electronic device storage case having a gap between the locking projection portion and the locking hole portion is used in an ECU of a motor vehicle, the locking projection portion and the locking hole portion make repeated contact with each other due to the vibrations generated in the running motor vehicle. This poses a problem of abnormal noises such as buzz, squeak and rattle. 
         [0005]    As a solution to this problem, there is known an electronic device storage case in which an elastic portion is provided in one of case members to elastically bias the case members away from each other when the case members are locked together by a locking projection portion and a locking hole portion (see, e.g., Japanese Application Publication No. 2003-37913). 
         [0006]    The electronic device storage case provided with the elastic portion is configured such that, when the locking projection portion and the locking hole portion are brought into engagement with each other, the elastic portion provided in one of the case members presses the other case member away from one case member. In this manner, the locking projection portion and the locking hole portion are press-contacted against with each other through the elastic portion so that no gap can be generated between the locking projection portion and the locking hole portion. This helps suppress loose engagement of the locking projection portion and the locking hole portion, which assists in preventing generation of abnormal noises. 
         [0007]    In the electronic device storage case disclosed in Japanese Application Publication No. 2003-37913, however, no consideration is given to those noises generated by a substrate within the storage case during occurrence of vibrations. In other words, the substrate may rattle within the storage case during occurrence of vibrations and may contact with the inner surface of the storage case, consequently generating abnormal noises. 
       SUMMARY OF THE INVENTION 
       [0008]    In view of the above, the present invention provides an electronic device storage case capable of preventing generation of abnormal noises caused by a substrate. 
         [0009]    In accordance with one aspect of the present invention, there is provided an electronic device storage case for use in storing a substrate therein. The case body includes a hollow box-shaped case body including an open surface with an opening, a bottom surface opposite to the opening and a sidewall extending upright from the peripheral edge of the bottom surface, wherein the sidewall of the case body including a plurality of deformable ribs each having a slant surface inclined inwards toward the bottom surface, and wherein the substrate is introduced into the case body through the opening and slidingly moves along the slant surface of each of the deformable ribs to make pressure contact with the slant surface. 
         [0010]    With the present invention, it is possible to provide an electronic device storage case capable of preventing generation of abnormal noises caused by a substrate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The objects and features of the present invention will become apparent from the following description of embodiments, given in conjunction with the accompanying drawings, in which: 
           [0012]      FIG. 1  is a section view showing certain major parts of an electronic device storage case in accordance with one embodiment of the present invention; 
           [0013]      FIG. 2  is an exploded perspective view of the electronic device storage case; 
           [0014]      FIG. 3  is a section view of the electronic device storage case; 
           [0015]      FIG. 4  is a section view of certain major parts of the electronic device storage case; 
           [0016]      FIG. 5  is an enlarged view showing a locking projection portion of the electronic device storage case; 
           [0017]      FIG. 6  is a perspective view of certain major parts of the electronic device storage case; 
           [0018]      FIG. 7  is a section view of certain major parts of the electronic device storage case; 
           [0019]      FIG. 8  is a plan view of the electronic device storage case; and 
           [0020]      FIG. 9  is a section view of the electronic device storage case. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0021]    Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings which form a part hereof. 
         [0022]    An electronic device storage case in accordance with one embodiment of the present invention will now be described with reference to  FIGS. 1 through 9 . 
         [0023]    Referring to  FIGS. 1 through 3 , the electronic device storage case of the present embodiment is used in, e.g., an ECU of a motor vehicle to store a substrate  3  therein. The electronic device storage case includes a generally rectangular box-shaped case body  1  with one surface thereof opened and a case cover  2  attached to the case body  1  to close the opening of the case body  1 . 
         [0024]    As shown in  FIG. 2 , the case body  1  includes a generally rectangular base portion  11  and body wall portions  12  extending from the peripheral edge of the base portion  11  in a substantially perpendicular relationship with the base portion  11 . In the description made herein below, the body wall portions  12  extending from the long sides of the base portion  11  will be referred to as “body wall portions  12 A” and the body wall portions  12  extending from the short sides of the base portion  11  will be referred to as “body wall portions  12 B”. If there is no need to distinguish the body wall portions  12 A and  12 B from each other, they will be collectively called “body wall portions  12 ”. 
         [0025]    A plurality of (two, in the present embodiment) locking projection portions  121  is arranged side by side along a longitudinal direction on the outer surface of each of the body wall portions  12 A near the opening of the case body  1 . 
         [0026]    As can be seen in  FIGS. 4 and 5 , each of the locking projection portions  121  includes a slant surface  121   a  inclined outwards as it extends from the opening of the case body  1  toward the base portion  11  and a locking surface  121   b  formed substantially parallel to the base portion  11  so as to interconnect the tip end of the slant surface  121   a  and the corresponding body wall portion  12 A, so that it has a substantially triangular cross-sectional shape. 
         [0027]    Two fitting jut portions  122  of generally triangular cross-sectional shape are formed side by side on the locking surface  121   b . Each of the jut portions  122  includes a slant surface  122   a  inclined toward the base portion  11  as it extends to the corresponding body wall portion  12 . 
         [0028]    Around diagonally opposed two corners of the case body  1 , cross ribs  110  of generally crisscross shape are arranged to protrude from the base portion  11  as shown in  FIGS. 3 and 6 . Each of the cross ribs  110  includes a support rib  111  substantially parallel to the long sides of the base portion  11  and a support rib  112  substantially parallel to the short sides of the base portion  11 . A projection  113  protrudes from the intersection point of each of the cross ribs  110  toward the opening of the case body  1 . 
         [0029]    The projection  113  has a generally cylindrical columnar shape. The end extension of the projection  113  is formed into a generally truncated cone shape such that the diameter thereof grows smaller toward the tip end thereof. 
         [0030]    Slant ribs (deformable ribs)  12   a  of generally triangular section shape are arranged on the body wall portions  12 A near two opposite corner portions of one longitudinal end of the case body  1  to protrude from the body wall portions  12 A, respectively. Each of the slant ribs  12   a  has a slant portion  12   b  inclined inwards as it extends from a position on the opening side of the case body  1  to the base portion  11 . In addition, a slant rib  12   a  inclined inwards as it extends from a position on the opening side of the case body  1  to the base portion  11  protrudes from substantially the center of the body wall portion  12 B arranged at the other longitudinal end of the case body  1 . 
         [0031]    In one corner portion of one longitudinal end of the case body  1  (where the cross ribs  110  do not exist) and substantially at the center of the other longitudinal end of the case body  1 , support ribs  13  of generally rectangular solid shape are arranged to protrude from the base portion  11  toward the opening of the case body  1 . In this regard, the tip ends of the support ribs  13  are flush with the tip ends of the support ribs  111  and  112 . 
         [0032]    The substrate  3  is put into the case body  1  from the opening of the case body  1  and is placed onto the cross ribs  110  and the support ribs  13 , at which time the projections  113  are inserted into insertion holes  3   a  formed in diagonally opposed two corners of the substrate  3 , thereby determining the position of the substrate  3  with respect to the case body  1 . Since the end extension of each of the projections  113  have a generally truncated cone-like tapering shape, the projections  113  can be easily inserted into the insertion holes  3   a  of the substrate  3 . 
         [0033]    When the substrate  3  is placed onto the cross ribs  110  with the projections  113  inserted into the insertion holes  3   a , the end portions of the substrate  3  are slidingly moved along the slant portions  12   b  of the slant ribs  12   a  and are pressed against the slant ribs  12   a . In this process, the substrate  3  is fitted to the cross ribs  110  while crushing the slant ribs  12   a . Thus, the substrate  3  is gripped by a plurality of (three, in the present embodiment) deformed slant ribs  12   a  within the case body  1  against movement in the transverse direction (in the direction orthogonal to the thickness direction of the substrate  3 ). 
         [0034]    A fixing piece  15  having screw-fixing holes  15   a  is formed on the outer surface of the base portion  11  to extend outwards beyond one of the body wall portions  12 B. The case body  1  is fixed to a holder member (not shown) by inserting screws (not shown) through the screw-fixing holes  15   a  of the fixing piece  15  and then threadedly tightening the screws into screw holes formed in the holder member. 
         [0035]    The case cover  2  has a rectangular box shape with one surface thereof opened. The case cover  2  includes a generally rectangular top panel portion  21  and cover wall portions  22  extending from the peripheral edge of the top panel portion  21  in a perpendicular relationship with the top panel portion  21 . In the description made herein below, the cover wall portions  22  extending from the long sides of the top panel portion  21  will be referred to as “cover wall portions  22 A” and the cover wall portions  22  extending from the short sides of the top panel portion  21  will be referred to as “cover wall portions  22 B”. If there is no need to distinguish the cover wall portions  22 A and  22 B from each other, they will be collectively called “cover wall portions  22 ”. 
         [0036]    A connector insertion block  23  and a connector insertion block  14  protrude outwards from one of the cover wall portions  22 B and one of the body wall portions  12 B, respectively. When the case cover  2  is fixed to the case body  1 , engaging protrusion portions  14   a  formed on the outer surface of the connector insertion block  14  come into engagement with engaging holes  24   a  of coupling portions  24  formed on the outer surface of the connector insertion block  23 , thereby forming a hollow box-shaped connector insertion portion  26 . 
         [0037]    A generally-rectangular connector insertion hole  26   a  is defined at the tip end of the connector insertion portion  26 . A connector  41  having signal lines  4  is introduced into the electronic device storage case through the connector insertion hole  26   a . Then, the connector  41  is connected to a connector  31  provided in the substrate  3 , whereby sensors or other components (not shown) are electrically connected to the substrate  3 . 
         [0038]    The case cover  2  is attached to the case body  1  with the openings of the case cover  2  and the case body  1  opposed to each other. At this time, the outer surfaces of the body wall portions  12 A and the inner surfaces of the cover wall portions  22 A face toward each other. Locking hole portions  221  of generally rectangular shape are formed in the cover wall portions  22 A in alignment with the locking projection portions  121  provided on the outer surface of the body wall portions  12 A. The locking projection portions  121  are inserted into and engaged with the locking hole portions  221 . When fixing the case body  1  and the case cover  2  together, they are first caused to move toward each other with the opening of the case body  1  opposed to the opening of the case cover  2 . Thus, the slant surfaces  121   a  of the locking projection portions  121  make contact with the tip ends of the cover wall portions  22 A. If the case body  1  and the case cover  2  are further moved toward each other, the inner surfaces of the cover wall portions  22 A are pressed by the slant surfaces  121   a  and are bent outwards along the slant surfaces  121   a . Subsequently, the locking projection portions  121  are fitted into the locking hole portions  221  of the cover wall portions  22 A. The locking projection portions  121  and the locking hole portions  221  are locked together, as a result of which the case cover  2  is attached to the case body  1 . 
         [0039]    When the locking projection portions  121  and the locking hole portions  221  are locked together, the locking projection portions  121  are fitted into the locking hole portions  221 . The inner surfaces of the locking hole portions  221  are slidingly moved on the slant surfaces  122   a  of the fitting jut portions  122 , thereby pressing and crushing the fitting jut portions  122 . Since the fitting jut portions  122  are formed into a generally triangular cross-sectional shape so that they can be inclined toward the base portion  11  as they extend from the tip ends of the locking projection portions  121  to the body wall portions  12 , the locking action occurs smoothly. As a result, the fitting jut portions  122  integrally formed with the locking projection portions  121  can be crushed within the locking hole portions  221  to fill the gaps existing between the locking projection portions  121  and the locking hole portions  221 . Since the gaps existing between the locking projection portions  121  and the locking hole portions  221  are filled with the fitting jut portions  122 , it is possible to restrain the locking parts from rattling during occurrence of vibrations and to prevent generation of abnormal noises through the use of a simple structure, even if manufacturing errors exist in the locking projection portions  121  and the locking hole portions  221 . 
         [0040]    As shown in  FIGS. 1 and 7 , push ribs  25  of generally trapezoidal plate shape having a cross-sectional area gradually decreased from the top panel portion  21  toward the opening of the case cover  2  are formed in the case cover  2  to protrude from the top panel portion  21 . The tip ends of the push ribs  25  make contact with one surface of the substrate  3  (the upper surface of the substrate  3  in  FIG. 7 ). The tip ends of the push ribs  25  are opposed through the substrate  3  to the tip ends of the support ribs  13  and the tip ends of the support ribs  111  provided at one longitudinal end of the case body  1 , which remain in contact with the other surface of the substrate  3 . In other words, the substrate  3  is gripped by the push ribs  25 , the support ribs  13  and the support ribs  111  and is restrained from rattling in the thickness direction. 
         [0041]    As shown in  FIGS. 8 and 9 , a plurality of generally U-shaped cutouts  21   a  is formed in the top panel portion  21 . Leaf spring portions  21   b  having elasticity acting in the thickness direction are formed in the areas of the top panel portion  21  surrounded by the respective cutouts  21   a . Push portions  21   c  of generally cylindrical columnar shape are attached to the tip ends of the leaf spring portions  21   b  in such a manner as to protrude toward the opening of the case cover  2 . The push portions  21   c  make contact with one surface of the substrate  3  at the tip ends thereof. Since the leaf spring portions  21   b  have elasticity acting in the downward direction (in the direction in which the push portions  21   c  are biased toward the substrate  3 ), the push portions  21   c  can push one surface of the substrate  3 . Thus, the push portions  21   c  is able to further restrain the substrate  3  from rattling in the thickness direction. 
         [0042]    With the electronic device storage case of the present embodiment, the substrate  3  is gripped by a plurality of slant ribs  12   a  within the storage case and is retrained from rattling. This makes it possible to prevent generation of abnormal noises caused by the substrate  3 . 
         [0043]    The support ribs  13 , the cross ribs  110 , the push ribs  25  and the push portions  21   c  further restrains the substrate  3  from rattling in the thickness direction. This makes it possible to reliably suppress the rattling of the substrate and to prevent generation of abnormal noises even when there are generated vibrations. 
         [0044]    With the electronic device storage case of the present embodiment, it is therefore possible to prevent generation of rattling sounds both in the locking parts of the locking projection portions  121  and the locking hole portions  221  and in the substrate  3  stored within the electronic device storage case. 
         [0045]    While the fitting jut portions  122  are made of a resin in the present embodiment, they may be formed from an elastic material. In this case, if the locking projection portions  121  and the locking hole portions  221  are disengaged from each other, the fitting jut portions  122  are elastically restored to the original state. 
         [0046]    Therefore, even when the case cover  2  is re-attached to the case body  1 , the locking projection portions  121  and the locking hole portions  221  are kept free from rattling. This makes it possible to prevent generation of abnormal noises. 
         [0047]    In the present embodiment, the locking projection portions  121  are formed in the case body  1  and the locking hole portions  221  are formed in the case cover  2 . Alternatively, the locking hole portions  221  may be formed in the case body  1  and the locking projection portions  121  may be formed in the case cover  2 . 
         [0048]    While the invention has been shown and described with respect to the embodiments, it will be understood by those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.