Patent Abstract:
The present invention provides a laminate printed board having a novel structure that is able to ensure alignment accuracy of the interboard terminals soldered to one printed board and that is also able to achieve a simplification of the process of soldering the interboard terminals. Through-hole lines in which a plurality of through-holes extend in lines are formed on a first printed board. Additionally, a press-fitting fastener hole is formed within the through-hole lines and a first end of an interboard terminal is press-fitted and fastened to the press-fitting fastener hole. Additionally, first ends of others of the interboard terminals are inserted through and flow soldered to through-holes on the first printed board.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority under 35 U.S.C. §119 of Japanese Application No. 2011-185598, filed on Aug. 29, 2011, the disclosure of which is expressly incorporated by reference herein in its entirety. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a laminate printed board in which two printed boards are laminated and connected by a plurality of interboard terminals, and a manufacturing method thereof 
         [0004]    2. Description of Related Art 
         [0005]    Conventionally, a laminate printed board in which two printed boards are laminated and mutually connected by a plurality of interboard terminals, such as that described in Japanese Patent Laid-open Publication No. 2009-26464 (Related Art 1), for example, has been used as an internal circuit in an electrical connection box, such as a junction box mounted in an automobile. 
         [0006]    In this type of laminate printed board, first ends of a plurality of interboard terminals are inserted through and soldered to one set of respective through-holes on a first printed board. Also, second ends are inserted through and soldered to another set of respective through-holes on a second printed board. Thus, should the plurality of interboard terminals not be accurately positioned at the stage of soldering to the first printed board, there is a risk that insertion through the through-holes of the second printed board will become difficult. 
         [0007]    Supporting the plurality of interboard terminals with a synthetic resin base has been suggested in the laminate printed board described in Related Art 1. However, such a configuration leads to an increase in the number of components due to the necessity of a base as a separate component. In addition, there is a risk that the base may thermally expand from heat of soldering or the like, pulling on the interboard terminals and producing positional drift. Good alignment accuracy thus cannot necessarily be ensured and cracks may occur in the soldering portions of the interboard terminals. 
         [0008]    In addition, soldering the interboard terminals to the two printed boards requires the first ends of the interboard terminals first be in a state inserted through the through-holes of the first printed board, immersing the bottom surface of the printed board in a soldering pot to be flow soldered, then inserting the second ends through the through-holes of the second printed board to form an assembly, and inverting the assembly to immerse in the soldering pot the bottom surface of the second printed board, on which the second ends project, to be flow soldered once more. The process had been cumbersome and required time and effort. In particular, in a case where the electronic components mounted on the printed board are of a surface-mounted type only, a flow soldering process must be performed to solder only the interboard terminals, separate from the reflow soldering process for the surface-mounted components, and there is a risk that this may lead to a decrease in manufacturing efficiency. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention was provided with the above-described situation as background. In order to address the problem, a laminate printed board having a novel structure is provided that is able to ensure alignment accuracy of the interboard terminals soldered to one printed board without leading to an increase in the number of components, and that is also able to achieve a simplification of the process of soldering the interboard terminals. In addition, a novel manufacturing method for the laminate printed board is provided which can be favorably used to manufacture such a laminate printed board. 
         [0010]    One aspect of the laminate printed board is a laminate printed board in which a first printed board and a second printed board are spaced apart. In addition, the first printed board and the second printed board are mutually connected by a plurality of interboard terminals, both ends of which are inserted through and soldered to a plurality of through-holes provided thereon. The plurality of through-holes are formed in a line on the first printed board, and within the line of through-holes, at least one press-fitting fastener hole is formed passing through the first printed board. Of the plurality of interboard terminals, a first end of one of the interboard terminals is press-fitted and fastened to the press-fitting fastener hole and, in addition, the first ends of the other interboard terminals are inserted through and reflow soldered to the through-holes on the first printed board, while second ends of the plurality of interboard terminals are inserted through and flow soldered to the through-holes on the second printed board. 
         [0011]    According to the laminate printed board having a configuration according to the present aspect, a press-fitting fastener hole to which the interboard terminal is able to press-fit and fasten is provided within the through-hole line on the first printed board. Accordingly, the plurality of interboard terminals are prepared as a chain terminal connected in parallel with a belt-like carrier and, by press-fitting and fastening one of the interboard terminals in the chain terminal to the press-fitting fastener hole, the other interboard terminals connected by the carrier can be held in a state inserted through the through-holes on the first printed board. As a result, the plurality of interboard terminals are fixed in position with respect to the first printed board and can be soldered with reflow soldering without requiring a special component such as a base. In particular, in a case where surface-mounted components are reflow soldered to the first printed board, the interboard terminals can be soldered simultaneously with the reflow soldering process of the surface-mounted components. Accordingly, soldering of the interboard terminals can be performed with a simple process, without requiring cumbersome effort such as, similar to convention, following a reflow soldering process for the surface-mounted components, the first ends of the interboard terminals are flow soldered to the first printed board, then the second ends are inserted through the through-holes of the second printed board and the resulting assembly is inverted, the bottom surface of the second printed board then being immersed again in the soldering pot. In addition, because a base supporting the interboard terminals is rendered unnecessary, no increase in the number of parts is involved, either. Moreover, risks can be reduced such as the work of inserting the interboard terminals into the through-holes on the second printed board becoming difficult when the alignment accuracy of the interboard terminals degrades due to thermal expansion of the base, or soldering cracks developing, and better manufacturing quality can be obtained. 
         [0012]    One press-fitting fastener hole may be formed in the through-hole line, and a plurality may also be formed. Moreover, the formation location of the press-fitting fastener hole in the through-hole line is not particularly limited. One press-fitting fastener hole may, for example, be formed in a central portion of the through-hole line, two press-fitting fastener holes may be formed at both end portions of the through-hole line, or the like. 
         [0013]    Another aspect of the laminate printed board is the press-fitting fastener hole in which a land is formed on a circumferential edge of an opening, on a side where the second ends of the interboard terminals project, and in which the interboard terminal press-fitted into the press-fitting fastener hole is reflow soldered to the land. 
         [0014]    According to the present aspect, by forming the land on the press-fitting fastener hole, the interboard terminal press-fitted and fastened to the press-fitting fastener hole can be reflow soldered along with the other interboard terminals and can be affixed by soldering to the first printed board. Accordingly, the interboard terminal press-fitted into the press-fitting fastener hole can be fastened more strongly thereto. As a result, the other interboard terminals can be held in position more securely with respect to the first printed board and, in addition, the risk can be reduced that manufacturing apparatuses and other components may be negatively affected by the interboard terminal press-fitted in the press-fitting fastener hole slipping free. 
         [0015]    Another aspect of the laminate printed board is the press-fitting fastener hole formed in the central portion of the through-hole line on the first printed board. 
         [0016]    According to the present aspect, when the chain terminal, in which the plurality of interboard terminals are connected in parallel by the belt-like carrier, is inserted through the through-holes on the first printed board, for example, the interboard terminal positioned in the central portion of the plurality of parallel interboard terminals can be press-fitted and fastened to the press-fitting fastener hole. Thereby, the plurality of interboard terminals connected by the belt-like carrier can be held with good balance by the interboard terminal positioned in the central portion. 
         [0017]    Another aspect of the laminate printed board is the press-fitting fastener hole as one of the plurality of through-holes which are electrically connected to printed wirings on the first printed board. 
         [0018]    According to the present aspect, the press-fitting fastener hole can be effectively used as a through-hole configuring an electrical circuit on the first printed board. As a result, space on the first printed board can be employed more effectively and, in addition, the interboard terminal press-fitted and fastened to the press-fitting fastener hole can also be employed more effectively as a conductive path electrically connecting the first printed board and the second printed board. 
         [0019]    An embodiment relating to a manufacturing method of the laminate printed board is a manufacturing method for a laminate printed board in which a first printed board and a second printed board are spaced apart and, in addition, the first printed board and the second printed board are mutually connected by a plurality of interboard terminals, both ends of which are inserted through and soldered to a plurality of through-holes provided thereon. The manufacturing method of the laminate printed board is a process of forming a plurality of through-holes in a line on the first printed board; a process of forming at least one press-fitting fastener hole passing through the first printed board within the line of through-holes; a process of preparing a chain terminal in which the plurality of interboard terminals are separably connected in parallel by a belt-like carrier; a process in which a first end of one interboard terminal in the chain terminal is press-fitted and fastened to the press-fitting fastener hole and, in addition, the first ends of the other interboard terminals connected by the carrier are inserted through and reflow soldered to the through-holes on the first printed board; and a process in which second ends of the plurality of interboard terminals in the chain terminal are inserted through and flow soldered to the through-holes on the second printed board. 
         [0020]    In the manufacturing method according to the present embodiment, the plurality of interboard terminals connected by the belt-like carrier are inserted through the through-holes on the first printed board and, in addition, at least one of the interboard terminals is press-fitted and fastened to the press-fitting fastener hole formed on the first printed board. Thereby, the plurality of interboard terminals prior to soldering can maintain position in a state inserted through the through-holes on the first printed board without requiring a special component such as a base. As a result, an increase in the number of components can be avoided to achieve a reduction in manufacturing costs and, in addition, a decrease in alignment accuracy and an occurrence of cracks in solder due to positional drift of the interboard terminals caused by thermal expansion of the base can be inhibited. An improvement in manufacturing quality can thus be achieved. 
         [0021]    Also, the first ends of the interboard terminals are inserted through and reflow soldered to the through-holes on the first printed board. Therefore, the time and effort to flow solder the first ends of the interboard terminals to the first printed board, then invert the assembly of the second printed board on the second ends of the interboard terminals and immerse the bottom surface of the second printed board once more in a soldering pot to perform flow soldering, as in a case where both end portions of the interboard terminals are flow-soldered, is not necessary and the soldering process can be simplified. In particular, in a case where surface-mounted components are reflow soldered to the first printed board, the interboard terminals can be reflow soldered to the through-holes on the first printed board in the same process as a reflow soldering process for the surface-mounted components, and better manufacturing efficiency can be obtained. 
         [0022]    In the present embodiment relating to the laminate printed board, the press-fitting fastener hole is formed within the line of through-holes on the first printed board and the first end of the interboard terminal is press-fitted and fastened to the press-fitting fastener hole. In addition, the first ends of the other interboard terminals are inserted through and reflow soldered to the through-holes on the first printed board, while the second ends of the interboard terminals are inserted through and flow soldered to the through-holes on the second printed board. Thereby, one interboard terminal of the chain terminal, in which the plurality of interboard terminals are connected in parallel by the belt-like carrier, is press-fitted and fastened to the press-fitting fastener hole. Accordingly, prior to soldering, the other interboard terminals can maintain position via the carrier in a state inserted through the through-holes of the first printed board. As a result, alignment accuracy of the plurality of interboard terminals soldered to the first printed board can be ensured and insertion through the through-holes of the second printed board can be performed more easily and reliably, without requiring a special component such as a base. In addition, the first ends of the interboard terminals are reflow soldered to the through-holes on the first printed board, and thus the soldering process can be further simplified, as compared to a case where both end portions are flow soldered. 
         [0023]    In the present embodiment relating to the manufacturing method of the laminate printed board, the press-fitting fastener hole is formed within the line of through-holes on the first printed board, and one of the interboard terminals in the chain terminal, in which the plurality of interboard terminals are connected by the belt-like carrier, is press-fitted and fastened to the press-fitting fastener hole. Thereby, the interboard terminal fastened to the press-fitting fastener hole and the plurality of interboard terminals connected via the carrier can maintain position and be soldered in a state inserted through the through-holes on the first printed board without using a special component such as a base. Accordingly, an improvement in manufacturing costs can be achieved through a reduction in the number of components. In addition, positional drift of the interboard terminals caused by expansion of the base or the like can be avoided, and thus the alignment accuracy of the interboard terminals can be ensured with better accuracy and the work of insertion through the through-holes on the second printed board can be performed more easily. Further, the first ends of the interboard terminals are reflow soldered, and thus the soldering process can be further condensed, as compared to the case where both end portions are flow soldered. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    The present invention is further described in the detailed description which follows, in reference to the noted plurality of drawings by way of non-limiting examples of exemplary embodiments of the present invention, in which like reference numerals represent similar parts throughout the several views of the drawings, and wherein: 
           [0025]      FIG. 1  is a perspective view of a laminate printed board for an embodiment of the present invention; 
           [0026]      FIG. 2  is a plan view of a first printed board; 
           [0027]      FIG. 3  is an expanded view of a main portion of  FIG. 2 ; 
           [0028]      FIG. 4  is a side view illustrating a portion of a chain terminal; 
           [0029]      FIG. 5  is an expanded view of a cross-section V-V in  FIG. 4 ; 
           [0030]      FIG. 6  is an explanatory cross-sectional view for describing an insertion state of interboard terminals through the first printed board; and 
           [0031]      FIG. 7  is an explanatory view for describing a soldering process of the interboard terminals to the first printed board. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0032]    The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show structural details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description is taken with the drawings making apparent to those skilled in the art how the forms of the present invention may be embodied in practice. 
         [0033]    Hereafter, an embodiment of the present invention is described with reference to the figures. 
         [0034]    First,  FIG. 1  illustrates a laminate printed board  10  for the embodiment of the present invention. The laminate printed board  10  is accommodated within a case of an electrical connection box not shown in the drawings, and configures an internal circuit of the electrical connection box. The laminate printed board  10  is configured by a first printed board  12  and a second printed board  14  being disposed in a laminate state opposing each other, spaced apart, and mutually connected by a plurality of interboard terminals  16 . 
         [0035]      FIG. 2  illustrates the first printed board  12 . The first printed board  12  according to the present embodiment is produced by forming a plurality (four in  FIG. 2 ) of first printed boards  12  in a connected state on one board  17  and cutting out each one. The first printed board  12  has a substantially longitudinal rectangular shape. In an outer peripheral portion of the first printed board  12 , on one long side portion and a pair of short side portions, through-hole lines  20   a,    20   b , and  20   c  are respectively formed, in which a plurality of through-holes  18   a  are formed in lines along the outer peripheral edges of the first printed board  12 . Each of the through-hole lines  20   a ,  20   b,  and  20   c  has a substantially similar configuration to one another, and thus the through-hole line  20   a  will be described below as an example. 
         [0036]    In the through-hole line  20   a,  a plurality of through-holes  18   a  are formed in one line. As shown in  FIG. 3 , the through-holes  18   a,  as conventionally known, are formed of a circular through-hole passing through the first printed board  12 . At the through-holes  18   a,  a land  24  is formed on a circumferential edge of an opening on a surface  22  on the first printed board  12  facing the second printed board  14  and, in addition, an inner peripheral surface is plated. Also, each of the through-holes  18   a  is connected to a printed wiring  26  formed on the first printed board  12 . 
         [0037]    Further, on the first printed board  12 , one press-fitting fastener hole  28  is formed at a central portion in each of the through-hole lines  20   a,    20   b,  and  20   c.  The press-fitting fastener hole  28  has a circular through-hole shape passing through the first printed board  12 . The inner diameter measurement φ of the press-fitting fastener hole  28  is made smaller compared to the inner diameter measurement φ′ of the through-holes  18   a,  and the press-fitting fastener hole  28  is set to a size so that the interboard terminal  16  inserted therethrough is press-fitted to contact the inner circumferential surface of the press-fitting fastener hole  28 . 
         [0038]    The press-fitting fastener hole  28  in the present embodiment in particular, similar to the rest of the plurality of through-holes  18   a  formed in the through-hole line  20   a,  is formed of a through-hole electrically connecting the second printed board  14  with the first printed board  12  via the interboard terminal  16 . Therefore, in the press-fitting fastener hole  28 , the land  24  is formed on the circumferential edge of the opening on the surface  22 . In addition, the inner peripheral surface is plated, and the press-fitting fastener hole  28  is connected to the printed wiring  26  formed on the first printed board  12 . 
         [0039]    Moreover, the inner diameter measurement φ of the press-fitting fastener hole  28  is made smaller than the inner diameter measurement φ′ of the other through-holes  18   a;  however, the inner diameter measurement φ of the press-fitting fastener hole  28  may also have an inner diameter measurement made smaller by making a diameter of a bore-hole from a drill or the like when piercing the through-holes  18   a  in the first printed board  12  smaller than the through-holes  18   a,  for example. Alternatively, as in the present embodiment, in a case where the press-fitting fastener hole  28  is also used as a through-hole, the diameter of the bore hole is made equal to the through-holes  18   a  and a thickness measurement of the plating deposited on the inner circumferential surface is made thicker than the through-holes  18   a.  Thereby, the inner diameter measurement φ of the press-fitting fastener hole  28  can also be made smaller, or the like, than the inner diameter measurement φ′ of the through-holes  18   a.  When done in this way, the press-fitting fastener hole  28  can also be bored with the same drill as the through-holes  18   a  without requiring changing of the drill. In addition, plating thickness is ensured and thus a risk of the plating peeling during press-fitting of the interboard terminal  16  can also be reduced. 
         [0040]    Meanwhile, the second printed board  14  is conventionally known, and has a longitudinal rectangular shape larger than the first printed board  12 . Though a detailed illustration is omitted, through-holes  18   b  are respectively pierced in the second printed board  14  in positions corresponding to each of the through-holes  18   a,  which include the press-fitting fastener hole  28 , on the first printed board  12 . 
         [0041]    The first printed board  12  and the second printed board  14  are mutually connected by the plurality of interboard terminals  16 . A chain terminal  32  is favorably used as the interboard terminals  16 , as shown in  FIG. 4 , in which the plurality of interboard terminals  16  are connected in parallel by a belt-like carrier  30 . Each of the interboard terminals  16  has a straight shape formed by a metallic wire rod having a substantially square shape in cross-section and being cut at a predetermined length. A pair of nub-like abutments  34  projecting to both outward sides are formed at both end portions in a length direction of the interboard terminal  16  by crushing or the like. 
         [0042]    The plurality of such interboard terminals  16  are connected by the carrier  30  in a parallel state extending in parallel to one another. The carrier  30  is formed from a thin metallic plate and is successively formed with a plurality of unit portions  36 . In addition, the carrier  30  is made to be easily severable between each of the unit portions  36 . As shown in  FIG. 5 , latching portions  38  rising up perpendicularly are formed curving at both terminal edges of each unit portion  36 . The interboard terminal  16  is made so as to fit into and be held within cutaways  40  formed on the latching portions  38 . Further, between the latching portions  38  on each of the unit portions  36 , a fastener clip  42  having substantially an L-shape in cross-section is formed by being cut away, and the interboard terminal  16  is fastened and held with the fastener clip  42 . Moreover, the fastener clip  42  partially overlaps with the interboard terminal  16  and, by pulling the carrier  30  away downward in  FIG. 5 , a latched state between the interboard terminal  16  and the fastener clip  42  can be easily released and thus the interboard terminal  16  is made easily separable from the carrier  30 . In addition, the chain terminal  32 , in which the plurality of interboard terminals  16  are connected in parallel by the carrier  30 , is configured by the interboard terminals  16  being held by each of the unit portions  36 . Furthermore, in a state connected to the carrier  30 , a placement interval Pc for each of the interboard terminals  16  is made to equal a placement interval Pt of the through-holes  18   a  and  18   b,  including the press-fitting fastener holes  28 , on the first printed board  12  and the second printed board  14  (see  FIG. 3 ). 
         [0043]    In addition, in a state connected to the carrier  30 , the interboard terminals  16  can be cut away to the same number as the through-holes  18   a,  including the press-fitting fastener hole  28 , in the through-hole lines  20   a,    20   b,  and  20   c  on the first printed board  12  by the carrier  30  in this type of chain terminal  32  being severed. The first ends of each of the interboard terminals  16  are then inserted through the through-holes  18   a,  including the press-fitting fastener hole  28 , in each of the through-hole lines  20   a,    20   b,  and  20   c.  Furthermore, the amount of insertion of the interboard terminals  16  into the through-holes  18   a  is regulated by the abutments  34  touching the first printed board  12 . As shown in  FIG. 6 , the interboard terminal  16  inserted through the press-fitting fastener hole  28  is fastened in a state projecting from the first printed board  12  by being press-fitted into the press-fitting fastener hole  28 , without requiring soldering. Furthermore, in the present embodiment, the inner diameter measurement φ of the press-fitting fastener hole  28  is made smaller than the inner diameter measurement φ′ of the through-holes  18   a  by increasing the thickness of the plating on the inner circumferential surface. In addition, the inner diameter measurement φ of the press-fitting fastener hole  28  is made smaller than a maximum outer shape measurement of an axially-perpendicular cross-section at the end portion of the interboard terminal  16  inserted through the press-fitting fastener hole  28 . Thereby, the interboard terminal  16  inserted through the press-fitting fastener hole  28  is press-fitted and fastened while scraping away the plating on the inner circumferential surface of the press-fitting fastener hole  28 . In addition, the first ends of the other interboard terminals  16  are held in position in a state inserted through each through-hole  18   a  without requiring any particular press-fitting force due to being connected by the carrier  30  to the interboard terminal  16  press-fitted and fastened to the press-fitting fastener hole  28 . Under these conditions, by being reflow soldered in the state inserted through each of the through-holes  18   a,  including the press-fitting fastener hole  28 , each of the interboard terminals  16  is electrically connected to each of the through-holes  18   a,  including the press-fitting fastener hole  28 , and is provided projecting from the first printed board  12 . 
         [0044]    In addition, due to the overlap of the first printed board  12 , on which the interboard terminals  16  are projectingly provided, with the second printed board  14 , the second ends of the interboard terminals  16  projecting from the first printed board  12  are inserted through each of the through-holes  18   b  on the second printed board  14 . Furthermore, the amount of insertion of the interboard terminals  16  into the through-holes  18   b  is regulated by the abutments  34  touching the second printed board  14 . Further, on the second printed board  14 , a plurality of connector terminals  44 , relays  46 , and the like connected to fuses, connectors, and the like are inserted through through-holes not shown in the drawings. The end portions of the interboard terminals  16  inserted through the through-holes  18   b  are flow soldered along with the connector terminals  44  and the relays  46 . Thereby, the laminate printed board  10  is configured in which the first printed board  12  and the second printed board  14  are mutually connected by the plurality of interboard terminals  16 . 
         [0045]    Furthermore, the laminate printed board  10  of this type is favorably manufactured as below, for example. First, the first printed board  12  and the second printed board  14  are prepared. Using a conventionally known procedure, the first printed board  12  is formed with the plurality of through-holes  18   a  in a line, thereby forming the through-hole lines  20   a,    20   b,  and  20   c.  Further, as described above, the press-fitting fastener hole  28  is formed within each of the through-hole lines  20   a,    20   b,  and  20   c,  for example by making the bore-hole diameter of a drill smaller than the through-holes  18   a,  or by making the thickness measurement of the plating larger than the through-holes  18   a.  In addition, the chain terminal  32  is prepared and, by severing the carrier  30  in the chain terminal  32 , the interboard terminals  16  are prepared by being cut away in a state where connection to the carrier  30  is maintained, to the same number as the through-holes  18   a,  including the press-fitting fastener hole  28 , in the through-hole lines  20   a,    20   b,  and  20   c  on the first printed board  12 . 
         [0046]    Next, as shown in  FIG. 7 , first ends of each of the interboard terminals  16  are inserted through each of the through-holes  18   a,  including the press-fitting fastener hole  28 , in the through-hole lines  20   a,    20   b,  and  20   c  on the first printed board  12 . Furthermore, although omitted from the drawings, a cream solder in a paste form for reflow soldering is printed on the first printed board  12 . Further, surface-mounted components such as an LSI are disposed on the surface  22  of the first printed board  12 , as necessary. Moreover, in  FIG. 7 , by inserting each of the interboard terminals  16  through each of the through-holes  18   a  on four of the first printed boards  12  prior to cutting away from the board  17 , soldering of the interboard terminals  16  to four of the first printed boards  12  is performed simultaneously. During this insertion, the interboard terminal  16  inserted through the press-fitting fastener hole  28  is fastened in a press-fitted state to the press-fitting fastener hole  28 . Accordingly, the other interboard terminals  16  are connected by the carrier  30  to the interboard terminal  16  press-fitted and fastened to the press-fitting fastener hole  28  and are held in a state inserted through each of the through-holes  18   a.  In addition, by dropping the first printed board  12 , in which the interboard terminals  16  have been inserted through the through-holes  18   a,  into a reflow kiln and by melting the solder, each of the interboard terminals  16  is reflow soldered to the first printed board  12 , along with the surface-mounted components. As described above, in the present embodiment, reflow soldering of four of the first printed boards  12  is performed simultaneously and, after reflow soldering of the interboard terminals  16  is completed, each of the first printed boards  12  is individually cut away from the board  17 . 
         [0047]    Next, as shown in  FIG. 1 , in addition to inserting the connector terminals  44  and the relays  46  through the through-holes (not shown in the drawing) of the second printed board  14 , the first printed board  12  obtained previously is overlapped on the second printed board  14 , and the second ends of the interboard terminals  16  projecting from the first printed board  12  are respectively inserted through the corresponding through-holes  18   b  of the second printed board  14 . Moreover, in this state, each of the interboard terminals  16  is preferably maintained in a state connected to the carrier  30 . Also, by immersing the reverse surface of the second printed board  14  in a soldering pot filled with liquid solder, the interboard terminals  16  are flow soldered to the second printed board  14  along with the connector terminals  44 , the relays  46 , and the like. Thereafter, by peeling away the carrier  30  connecting the interboard terminals  16 , the laminate printed board  10  can be obtained. 
         [0048]    According to the laminate printed board  10  having such a configuration, the press-fitting fastener hole  28  capable of press-fitting and fastening the interboard terminal  16  is formed in each of the through-hole lines  20   a,    20   b,  and  20   c  on the first printed board  12 . Thereby, in a state where the plurality of interboard terminals  16  are connected to the carrier  30 , by press-fitting and fastening one of the interboard terminals  16  to the press-fitting fastener hole  28 , the other interboard terminals  16  can be held via the carrier  30  in a state inserted through each of the through-holes  18   a.  As a result, the plurality of interboard terminals  16  can be held in a state inserted through the through-holes  18   a  without requiring a special component such as a base. In addition, the plurality of interboard terminals  16  are reflow soldered to the first printed board  12  in a state inserted through the through-holes  18   a.  Thereby, as in a case where the interboard terminals  16  are flow soldered to both the first printed board  12  and the second printed board  14 , for example, the time and effort of immersing in the soldering pot the reverse surface of the first printed board  12  on which the first ends of the interboard terminals  16  project, and then once again immersing in the soldering pot the reverse surface of the second printed board  14  on which the second ends project becomes unnecessary, and a simplification of the soldering process can be achieved. In particular, in a case where the surface-mounted components are provided on the surface  22  of the first printed board  12 , the interboard terminals  16  can be soldered to the first printed board  12  in the reflow soldering process of the surface-mounted components, and further efficiency of the manufacturing process can be achieved. 
         [0049]    In particular, in the present embodiment, the land  24  is formed on the press-fitting fastener hole  28 , and the interboard terminal  16  press-fitted and fastened to the press-fitting fastener hole  28  is also fastened by soldering to the land  24 . Thereby, the interboard terminal  16  can be fastened more securely to the press-fitting fastener hole  28 , and the risk can be reduced that the interboard terminal  16  inserted through the press-fitting fastener hole  28  may slip free and become a foreign body with respect to manufacturing apparatuses, and thus impart a negative effect. Further, by connecting the press-fitting fastener hole  28  to the printed wiring  26  as well, the press-fitting fastener hole  28  can also be used as a through-hole configuring an electrically conductive path, and further efficient use of the first printed board  12  can be achieved. 
         [0050]    The press-fitting fastener hole  28  is formed in a central portion of each of the through-hole lines  20   a,    20   b,  and  20   c.  Thereby, by fastening the central portion of the plurality of the interboard terminals  16  connected by the carrier  30  to the press-fitting fastener hole  28 , the plurality of interboard terminals  16  on both sides of the interboard terminal  16  fastened to the press-fitting fastener hole  28  can be supported with good balance. Moreover, only one press-fitting fastener hole  28  is formed in each of the through-hole lines  20   a,    20   b,  and  20   c.  When the plurality of interboard terminals  16  are inserted through the through-holes  18   a,  only one of the interboard terminals  16  is press-fitted into the press-fitting fastener hole  28 , and thus the first printed board  12  can be easily assembled, without requiring an excessive press-fitting force. 
         [0051]    An embodiment of the present invention was described above; however, the present invention is not limited to this specific description. For example, a press-fitting fastener hole is not required to be a through-hole configuring a conductive path, and may be a simple through-hole passing through the first printed board. When made in such a way, even where there is a risk of damaging the press-fitting fastener hole during press-fitting of the interboard terminal, there is no need to weigh a reduction in reliability of the electrical connection. Further, the land formed on the press-fitting fastener hole is not strictly required, either. However, the land alone may be formed, without being connected to the printed wiring. When made in such a way, the interboard terminal press-fitted and fastened to the press-fitting fastener hole is soldered to the land and can ensure a stronger fastening force. 
         [0052]    Further, the shape of the opening of the press-fitting fastener hole is not limited to a specific shape, so long as the inserted interboard terminal can be press-fitted and fastened thereto. Therefore, in a case where the interboard terminal has a flattened shape in cross-section or the like, for example, the press-fitting fastener hole may have a long hole shape, or the like. Moreover, a plurality of the press-fitting fastener holes may be formed in the through-hole lines, and are not limited necessarily to being formed in the central portion of the through-hole lines. Therefore, for example, two of the press-fitting fastener holes may be formed at both end portions of the through-hole lines, or the like. 
         [0053]    It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the present invention has been described with reference to exemplary embodiments, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to particular structures, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims. 
         [0054]    The present invention is not limited to the above described embodiments, and various variations and modifications may be possible without departing from the scope of the present invention.

Technology Classification (CPC): 8