Electrical connection box

Abstract: The electrical connection box (1) is equipped with a bus bar laminate (3) composed of bus bars (5) and insulation layers (6), and a printed circuit board (4) electrically connected with the bus bar laminate (3). First ends (13a) of connecting terminals (13) are soldered to the conductors (8) of the circuit board (4). Tabs (5a) are provided by bending up parts of the bus bar (5). An insertion groove (26) is provided in the end part of each male tab (5a), and the second ends (13b) of the connecting terminals (13) are inserted into and held in the insertion grooves. Alternatively the groove is in the terminal (13) and the tab (5a) is inserted in the groove. Reliable and economic connection is obtained.

Description: FIELD OF THE INVENTION The present invention relates to an electrical connection box suitable to be mounted on, for example, an automobile or other vehicle, and more specifically relates to a connecting structure for a printed circuit board and a bus bar laminate in the electric connection box. BACKGROUND OF THE INVENTION An example of an electrical connection box suitable to be mounted in an automobile or the like is shown in Fig. 5, which is contained in unpublished Japanese application no. 11-344812 of 1 July 1999. The box 41 is equipped with a bus bar laminate 44 composed of bus bars 42 and insulator layers 43, and a printed circuit board 45 having the function of an ECU (electronic control unit). Various electrical parts 46 are mounted on one face of the printed circuit board 45. The terminals of these electrical parts 46 are soldered in the plated through-holes of the board 45. A pair of housings 47 are provided on the uppermost insulator layer 43, and connectors 48 of bent sheet metal are held in those housings 47. Male tabs 42a formed by bending up portions of the bus bars 42 are inserted and held in the lower opening parts of the respective connectors 48. Connecting terminals 50 are partially molded in resin blocks 49, and their first ends 50a are soldered to the plated through-holes of the circuit board 45. The second ends 50b of the respective connecting terminals 50 are inserted and held in the upper opening parts of the connectors 48. In this way, the circuit board 45 and the bus bar laminate 44 are electrically connected. However, when the number of parts are large, the number of steps needed for assembly increases, because a large number of the connectors 48 are required in this electrical connection box 41. Accordingly, this has resulted in complication of structure, cost increase of products, and also weight increase of products. EP 0 727 851 A2 describes an electrical connection construction between an electrical connection box and an electronic circuit unit, showing the features of the first part of claim 1. The connections between the two components are formed by inserting a tab on one of the units into a pressing contact slit in a tab on the second unit. SUMMARY OF THE INVENTION The present invention has as its object to provide an electrical connection box containing a printed circuit board and a bus bar laminate, which can have a simple structure and can be of low cost and light weight. According to the invention there is provided an electrical connection box as set out in claim 1. Preferably on the bus bar laminate there is at least one housing composed of insulation material upstanding towards the printed circuit board, containing a plurality of the connection tabs and having an outer end against which the molded resin block abuts. BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will now be described by way of non-limitative example with reference to the accompanying drawings, in which:- Fig. 1 is an exploded schematic perspective view of the electrical connection box which is one embodiment of the present invention. Fig. 2 is a sectional view of the electrical connection box of Fig. 1. Fig. 3 is a perspective view of the molded connection articles used in the electrical connection box of Fig. 1. Fig. 4(a) and Fig. 4(b) are enlarged perspective views of a second end of a connecting terminal and the end part of male tab, in the box of Fig. 1. Fig. 5 is a sectional view showing a known electrical connection box, described above. DETAILED DESCRIPTION OF THE EMBODIMENTS The electric connection box 1, suitable to be mounted in an automobile, which embodies the present invention illustrated in detail in Figs. 1 to 4 has a bus bar laminate 3 and a printed circuit board 4 having the function of an ECU unit mounted in an upper case 2 made of suitable molded polymeric resin. The bus bar laminate 3 which has an approximately rectangular shape as a whole is formed by alternatively laminating bus bars 5 composed of electro-conductive metal sheet and insulation layers 6 made of a resin. Connection tabs 5a are provided where wanted by bending portions of these bus bars 5 upwardly. The bus bar laminate 3 is arranged at the opening of the upper case 2. A lower case 7 also of suitable resin is fitted to the upper case 2. The printed circuit board 4 has a rectangular shape, and is of smaller size than the bus bar laminate 3. The circuit board 4 in the present embodiment is a double face plate having conductor patterns on both faces, which are mutually connected through the plated through-holes 8, into which connection pins can be inserted. In Figs. 1 and 2, various electronic parts 9 (e.g. IC packages, resistances, capacitors and the like) are mounted on one face 4a of the print circuit board 4. Each of these electronic parts 9 has a plural number of terminals 10. The respective terminals 10 are inserted and soldered in the corresponding plated through-holes 8. Next, the structure connecting the printed circuit board 4 with the bus bar laminate 3 is described. Electrical connection between these two is provided by the molded connection articles 11, of which two are provided in the electrical connection box 1. The two molded connection articles 11 are arranged at two spaced locations at the parts-mounting face 4a of the print circuit board 4. As shown in Fig. 3, each molded connection article 11 has a plural number (here four) of connecting terminals 13 partially molded in resin blocks 12. The elongate rectangular parallelepiped resin blocks 12 are made of a resin molding material (for example, an epoxy or the like) having insulating property and heat resistance. As shown in FIG.2, the faces S3 of the resin blocks 12 abut the parts-mounting face 4a of the print circuit board 4, and it is preferred that the face S3 and the parts-mounting face 4a are not adhered together by an adhesive or the like. Accordingly, it may be also understood that the parts mounting face 4a is supported by the faces S3 of the resin blocks 12, though not adhered. The four connecting terminals 13 in each block 12 are made of a sheet electro-conductive metal material similar to that of the bus bars 5, in the present embodiment. Each terminal 13 is retained parallel and equally spaced from its neighbours by insert molding in the resin blocks 12. As shown in Fig. 3, the second end parts A2 of the terminals 13 are linear and protrude perpendicularly from the face S1 of the resin blocks 12. On the other hand, the exposed first end parts A1 are rectangularly bent and protrude from the side face S2 of the resin block 12. Mold shrink protection holes 14 are formed between the respective connecting terminals 13, in the face S1. Within the resin block 12 each terminal 13 is also rectangularly bent. As shown in Fig. 2, the first ends 13a of the first end parts A1 of the terminals 13 are inserted and soldered in the plated through-holes 8 of the circuit board 4. The first end parts A1 are inserted in the plated through-holes 8 from the same direction as the terminals 10 of the other electronic parts 9. As shown in Fig. 1, upstanding housings 22 are provided as required at two spaced locations of the insulation layer 6 which is situated on the uppermost bus bar layer in the laminate 3. Specifically, these housings 22 correspond in location with the two molded connection articles 11 attached to the print circuit board 4. These housings 22 are integrally formed with uppermost insulation layer 6 by molding using a synthetic resin as a material, as a rectangular box open at the upper end face. A plural number (here, four) of the tabs 5a stand upright in the rectangular parallelepiped shape inner cavity of each housing 22. The tabs 5a are mutually parallel and equally spaced. As shown in Fig. 4 the ends of the tabs 5a have insertion grooves 26 which extend in their longitudinal direction (the up and down direction of Fig. 4). In this embodiment the grooves 26 have a V-shape or a U-shape, with a pair of opposed semicircular protrusions 27 at the upper ends of the inner sides of the grooves 26. The gap between the pair of protrusions 27 is slightly narrower than the plate thickness of the connecting terminals 13. As shown in Fig. 4(b), the ends 13b of the second end parts A2 of the connecting terminals 13 are frictionally held by being inserted in the insertion grooves 26. The springiness of the material of the tabs 5a ensures a pressure contact between the protrusions 27 and the terminals 13. At their connection zone, the tab 5a and the end of the end 13b of the terminal lie in orthogonal planes. The printed circuit board 4 and the bus bar laminate 3 are thus electrically connected. Further, the face S1 of the block 12 where the second end parts A2 protrude is in contact with and supported by the upper end faces of the housings 22, as shown in Fig. 2. The following advantages can be obtained in this embodiment. (1) The second ends 13b of the respective connecting terminals 13 are inserted and fixed in the insertion grooves 26 at the ends of the respective tabs 5a. Therefore, the circuit board 4 and the bus bar laminate 3 can be electrically connected through only the molded connection articles 11. Accordingly, the large number of connections, such as connectors 48 in Fig. 7, which have previously been required is avoided. Therefore, the number of parts can be reduced, and the number of assembly steps can be reduced accordingly. Low cost of the electrical connection box 1 can be achieved, and it has a simple structure and low weight. (2) The plural number of the connecting terminals 13 are molded in mutually fixed positions in the resin blocks 12 with both end parts exposed. Therefore, troublesome work of soldering connecting terminals by positioning them one-by-one is unnecessary. Accordingly, the soldering work on the printed circuit board is easy, and the assembly of the electrical connection box 1 is simple. (3) The tabs 5a are arranged in the housings 22 provided on the insulation layer 6, so that the connection between the tabs 5a and the connecting terminals 13 are protected by the housings 22. Accordingly, resistance to shock and vibration is enhanced. Further, the waterproofing of the connections is enhanced because the connections are not exposed. The reliability of the device can be improved. (4) Further, the face S1 where the second ends 13b protrude on the resin blocks 12 is supported in contact with the upper end faces of the housings 22. Therefore, the printed circuit board can be horizontally and securely held at a fixed height. This also contributes to the improvement of the reliability of the device. (5) The first ends 13a of the terminals 13 are fixed by soldering them in the plated through-holes 8 of the print circuit board 4. Therefore, the deviation of the position of the respective terminals 13 is minimized, and deterioration of the reliability of connection between the printed circuit board 4 and the bus bar laminate 3 can be prevented. (6) In this embodiment, the insertion grooves 26 are provided not on the connecting terminals 13 but on the male tabs 5a. Therefore, it is unnecessary to use wide connecting terminals 13 to allow for the formation of the insertion grooves 26, and narrow connecting terminals 13 can be used. The insertion grooves 26 may be provided in the ends of the connecting terminals 13, instead of in the tabs 5a. Wider connecting terminals are used for the formation of the insertion grooves, and the plated through-holes 8 where their first ends are inserted in the board 4 are also made correspondingly larger. Since the shape of the housings 22 is not critical, the connection of the tabs 5a with the connecting terminals 13 may be exposed. The shape of the insertion grooves 26 is not limited to that of the embodiments shown. For example, variations of the shape of the pair of the protrusions 27 are possible. The printed circuit board 4 is not limited to one having a function as an ECU unit, and boards having other functions may be used. The housing 22 at the bus bar laminate side 3 need not be integrally molded. Namely, the housings 22 may be separately formed, and may be connected with the insulation layer 6. The terminals 10 of the electrical parts 9 and the connecting terminals 13 of the connection articles 11 need not be inserted to be soldered. For example, pads may be provided on the printed circuit board 4, and the terminals 10 and the connecting terminals 13 may be soldered on the pads according to the surface mounting system.

Claims: An electrical connection box comprising a bus bar laminate (3) having at least one bus bar (5) and at least one insulation layer (6) laminated together, and a printed circuit board (4), wherein said bus bar laminate (3) has a plurality of upstanding connection tabs (5a) formed by bending portions of the bus bar or bus bars, and a plurality of connection terminals (13) are connected by soldering at first ends to the printed circuit board and are connected at second ends directly to the connection tabs (5a), by means of in each case an insertion groove (26) provided in one of the connection tab (5a) and the connection terminal (13), with the other thereof being inserted into and held in said insertion groove, characterized by at least one molded block (12) of resin material in which a plurality of said connection terminals (13) are held by insert molding with their ends exposed outside the molded block. An electrical connection box according to claim 1, wherein on said bus bar laminate at least one housing (22) composed of insulation material is upstanding towards said printed circuit board, said housing (22) containing a plurality of said connection tabs (5a) and having an outer end against which said molded block (12) abuts. An electrical connection box according to claim 1 or 2, wherein at their connection zone, said connection tab and said connection terminal are formed of sheet metal arranged respectively in orthogonal planes. Use of an electrical connection box according to any one of claims 1 to 3, in a vehicle.

Inventors: ASAO TAKAHIRO, ASAO, TAKAHIRO, Asao, Takahiro, Sumitomo Wiring Systems, Ltd.
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 2000
Main classification: H01R9
IPC codes: H05K1, H01R9, H01R12, H05K7