JP2882280B2 - Circuit board and electric junction box provided with the circuit board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board and an electric junction box provided with the circuit board, and more particularly, to a conventional electric junction box including a junction box provided for branch connection of a wiring harness for an automobile. The present invention relates to a circuit board preferably used in place of a bus bar circuit board formed by punching a conductive metal plate.

[0002]

2. Description of the Related Art Conventionally, as a circuit board housed in an electric junction box, a bus bar 30 shown in FIG. 14 is generally used. As shown in FIG. 15, the bus bar 30 is formed by punching a metal plate 31 into a predetermined shape by a punch press.
The tab terminals 32 are formed by bending.

In the bus bar 30, the portion to be the tab terminal 32 protrudes from the conductive path 33 when the metal plate 31 shown in FIG. Therefore, a required space C for providing the tab terminal 32 is required, and the conductive path 32 must be provided with a required dimension S, so that the position of the tab terminal and the arrangement of the conductive path are very complicated, and one sheet It is difficult to provide tab terminals with high density on the bus bar, and a plurality of bus bars are often stacked. Further, tab terminals cannot be protruded at the same position in the vertical direction with the conductive path interposed therebetween. In this case, a plurality of bus bars must be stacked.

[0004] As described above, when a plurality of bus bars are provided, an insulating plate must be interposed between the bus bars. An electric junction box in which the plurality of bus bars and the plurality of insulating plates are laminated is There is a problem of increasing the size. In addition, busbar 3
In the case of No. 0, there is a problem that the yield of material removal is low and the cost is high, and there is a problem that a large machine and a die for press punching and bending are required.

To solve the above-mentioned problem, Japanese Patent Application Laid-Open
As shown in FIG. 16, a circuit board 35 made of a cast product formed by pouring a metal such as a zinc alloy into a mold has been proposed in JP-A-69163 and JP-A-63-175359. Since the shape of the circuit board 35 made of the cast product is determined by casting, the tab terminals 36 can be provided so as to protrude from the conductive path 37 at a relatively high density, and the terminals can be vertically arranged from the same place. 36A and 36B can also be provided.

[0006]

However, when a circuit board is formed by casting, a precise casting mold is required, and the casting mold must be provided every time a circuit pattern is changed. There is a drawback that the mold cost is high and the cost is very high. In the case of a cast product, the tab terminals can be protruded at a higher density than the conductive paths.However, there are cases where the conductive paths cannot be arranged at a high density on the same plane. Even as a cast product, a plurality of circuit boards must be stacked and housed in an electrical junction box. Therefore, an insulating plate must be interposed between these circuit boards, and the problem of an increase in the size of the electric connection box cannot be solved.

The present invention has been made in view of the above problems, and differs from a bus bar formed by a conventional method of punching a metal plate or a bus bar of a cast product as a circuit board housed in an electric junction box. It is an object of the present invention to provide a completely new circuit board which does not require an insulating plate even in such a case.

[0008]

According to the present invention, there is provided a circuit board which is accommodated in an electric connection box having a connector portion on an outer surface and has tab terminals protruding from the connector portion. The tab terminal made of a conductive plate protruded from the surface of the substrate, and the tab terminal made of a conductive plate protruded from the surface of the substrate, and filled into the groove in a molten state. A circuit board is provided in which a conductive circuit is formed on a substrate from a conductive path made of a conductive metal formed by bonding and fixing a tab terminal, and the tab terminal of the conductive circuit is projected to the connector portion. I have.

The substrate is preferably made of a flat plate, but it is not necessarily required to be a flat plate, and it may be made partially thick. In addition, it is preferable that the groove for the conductive path that opens on the surface of the substrate be opened on the same surface side,
If the groove is not continuous, it may be opened on the other side to form a plurality of grooves opened on both sides of the same substrate. In that case, after the molten metal is poured into the groove opened on one side and hardened, the substrate is reversed, the tab terminals are erected on the groove opened on the other side, and the molten metal may be poured and hardened. . Also,
The groove may have a rectangular cross section or a semicircular cross section, and the cross sectional shape is not limited. In some cases, the relay terminal connected to the tab terminal may protrude into the connector accommodating portion of the case. Further, when the buried portion of the tab terminal is press-fitted and held in the groove, the tab terminal has better stability if it has a rectangular cross section. When the embedded portion of the tab terminal is press-fitted into the mounting hole extending from the groove, it is preferable to improve the flow of the molten metal to be filled in a semicircular cross section. Also,

Preferably, the substrate is formed from a heat-resistant insulating resin. However, the material is not limited to resin as long as it is a heat-resistant insulating material, and may be formed from, for example, ceramics or the like.

The width of the groove for the conductive path formed on the substrate is
Set the same or slightly smaller than the thickness of the tab terminal,
It is preferable that the buried portion of the tab terminal is press-fitted into the groove and erected along the inner surface of the side wall of the groove. That is, when the molten metal poured into the groove is hardened, the tab terminal is adhered and held by the metal. Therefore, the tab terminal only needs to be held upright from the groove until the molten metal is poured into the groove and hardened. Therefore, it is sufficient to press-fit the groove and hold it along the inner surface of the side wall of the groove.

Alternatively, a mounting hole may be provided on the inner surface of the groove, and the embedded portion of the tab terminal may be press-fitted into the mounting hole so as to protrude from the groove. The mounting hole opening on the inner surface of the groove is preferably formed in the groove bottom surface and has a cross-sectional area equal to or less than the thickness of the tab terminal, and it is preferable to press-fit the embedded portion of the tab terminal into the mounting hole. The tab terminals can be reliably set up and held. Further, in this case, it is preferable that the tab terminal is not exposed to the other end surface without penetrating the mounting hole.

The tab terminal is provided on the opening side of the groove or /
Alternatively, tab terminals may be protruded from one surface side or both surface sides of the substrate so as to project from the bottom side of the groove. For example, while press-fitting a groove or a buried portion into a substrate and projecting toward the opening side of the groove, a tab terminal mounting hole penetrating from the surface opposite to the groove opening side to the bottom surface of the groove is formed in the substrate, and The buried portion of the tab terminal may be pressed into the mounting hole from the opposite surface, and the tip of the buried portion may protrude into the groove, so that the tab terminal protrudes on the surface opposite to the groove opening side. Further, the embedded portion of the tab terminal may be provided in the center portion, and the embedded portion may be press-fitted into a groove and a tab mounting hole formed so as to communicate with the groove, so that both ends of the tab terminal project from both surfaces of the substrate.

Preferably, molten solder is poured into the groove serving as the conductive path, and the conductive path is formed by the solder.
When solder is used, the substrate is formed of a resin having a high melting point higher than the melting point of the solder.

Further, the present invention provides a flat substrate made of the above-mentioned heat-resistant insulating material, a groove for a conductive path recessed from the surface of the substrate, and a standing member protruding from the inside of the groove to protrude from the surface of the substrate. A tab terminal made of a conductive plate, and a circuit board provided with a conductive path made of a conductive metal formed in contact with the tab terminal filled in the groove in a molten state, are housed inside the case and formed in the case. And an electric connection box provided with a circuit board protruding the tab terminal from the connector part.

When a plurality of the circuit boards are accommodated in a stacked state, there is no need to interpose an insulating plate between them as in the prior art, and the circuit boards can be stacked. In this case, when the laminated circuit board is located at a portion where the tab terminal protrudes, a through hole through which the tab terminal is inserted is provided in advance in the laminated circuit board.
In addition, at the time of lamination, they may be in contact with each other, but it is preferable to provide an air insulating portion with a slight gap.

[0017]

According to the circuit board of the present invention, the tab terminals set up in advance in the groove for the conductive path are fixed integrally with the conductive metal filling the groove, so that the conductive path and the tab terminal are energized, The bus bar formed by punching a conventional conductive metal plate and the bus bar circuit board formed by casting a conductive metal can perform exactly the same operation. In addition, since the conductive path is formed in a state buried on the surface of the insulating plate, and the tab terminal is protruded from the surface position of the insulating plate, the insulating plate required when the conventional bus bar is laminated is used. In addition to being unnecessary, the circuit board that also serves as the insulating plate and the bus bar of the present invention has a very small plate thickness as compared to the combined plate thickness of the bus bar and the insulating plate. It is possible to reduce the size of the electric junction box that houses the circuit board.

When the substrate is molded from a heat-resistant insulating resin,
A required circuit pattern can be easily formed.

The tab terminals can be easily erected from the grooves only by press-fitting the tab terminals into the grooves or mounting holes provided in the substrate.

When tab terminals are protruded from one side or both sides of the board, a connector can be attached to one or both sides of the electric connection box, and can be used properly according to the electric connection box to be accommodated. Can be done. In particular, if the connectors are provided on both sides, the size of the electric connection box can be reduced.

When solder is used as the molten metal to be filled in the groove for the conductive path, the conductive path can be formed inexpensively and easily, and can be securely fixed to the tab terminal.

When the circuit board is housed in the electric junction box, the interposition of the insulating plate is unnecessary when the circuit boards are stacked as described above, so that the electric junction box can be reduced in size and thickness.
Furthermore, as described in the operation of the fifth aspect, it is also possible to provide connector portions on both sides of the electric connection box.

When the circuit boards are accommodated in a laminated state, if the circuit boards to be laminated are provided with through holes, the tab terminals can be projected to the outer surface of the case.

The above-mentioned circuit board is only necessary to form a board, attach tab terminals to required portions of the board, and then pour molten metal into the board. A large-sized press machine and a large-sized mold required for casting are not required, and the production can be performed easily and inexpensively.

[0025]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 4 show a first embodiment. As shown in FIG. 1, a circuit board 1 is provided with a groove 2 having a path matching a desired conductive path on a substrate 2 molded from an insulating heat-resistant resin. A tab terminal 4 formed in advance from a conductive metal plate is provided upright at a required position of the groove 3. The molten solder 6 is poured into the groove 3 from the nozzle 5 of the solder supply device to the substrate 2 to which the tab terminal 4 is attached, thereby forming a conductive path 7 indicated by oblique lines in FIG.

In the circuit board 1 of the first embodiment having the structure shown in FIG. 3, a conductive path 7 formed by curing a solder 6 is formed on the upper surface side of an insulating substrate 2. From the required position of the conductive path 7, the tab terminal 4 adheres and fixes the lower end buried portion 4a located in the groove 3 with molten solder from a required position of the conductive path 7, The protruding portion 4b protrudes from the upper surface of the substrate 2 by a required dimension. As described above, since the conductive path 7 and the tab terminal 4 are adhered and fixed to be integrated, they are electrically connected to each other and form a conductive circuit similar to a conventional bus bar formed by punching a metal plate. .

The groove 3 has a rectangular cross section, and the tab terminal 4 has a width W1 equal to or slightly larger than the width W2 of the groove 3, as shown in FIGS. The lower end buried portion 4a of the tab terminal 4 is press-fitted into the inside 3 and is held upright from the groove 3 as shown in FIG. That is, the tab terminal 4
Of the tab terminal 4c is in contact with the bottom surface 3a of the groove 3.
The thin end surfaces 4d, 4e of the groove 3 are both side walls 3b, 3c
And one side wide surface 4f of the tab terminal 4
Along the wall 3d at the tip of the groove 3, the wall 3
It is supported by d and is held in an upright state.

As shown in FIGS. 1 and 2, when the molten solder 6 is poured in a state where the tab terminals 4 are erected at predetermined positions of the grooves 3, the lower end buried portions of the other wide surface 4g of the tab terminals 4 are formed. When the solder 6 is adhered to the solder 4a and the solder is hardened, the solder 6 is fixed in a state of protruding upward and vertically from the conductive path 7 made of the solder 6 (see FIG. 4).

A low melting point solder having a melting point of 200 ° C. or less is used as the solder 6 filling the groove 3 of the substrate 2.
The substrate 2 is formed of a resin having a heat-resistant temperature higher than the melting point of the solder 6. For example, a thermosetting resin (phenol resin, epoxy resin) having a heat resistance temperature of about 300 ° C., or a polyester resin (trade name: Exterpolymer PCT) is used. In addition, the molten metal poured into the groove 3 is not limited to the solder 6 and is preferably used as long as it has conductivity and has a low melting point. Further, the substrate 2 is not limited to the heat-resistant insulating resin,
Ceramics with excellent insulation and heat resistance (Al ₂ O ₃ ,
AlN).

As a method of pouring the molten solder 6 into the groove 3, the molten solder 6 is supplied from a solder supply device (not shown).
Is supplied while moving along the groove 3. In this case, when the nozzle 8 interferes with the protruding tab terminal 4, the molten solder 6 flows, so that even if the solder 6 is poured while avoiding the protruding portion of the tab terminal 4, Flows, and the solder 6 is poured around the tab terminals 4 to be bonded. Also, when supplying the solder 6 to the groove 3, if the substrate 2 is cooled,
Even a substrate 2 made of a material having poor heat resistance can be used.

FIG. 5 shows a second embodiment.
A mounting hole 10 for press-fitting a tab terminal is formed on the bottom surface 3a of the base. The cross-sectional area of the mounting hole 10 is set to be the same as or slightly smaller than the cross-sectional area of the tab terminal 4, and the lower part of the buried portion 4 a of the tab terminal 4 is press-fitted into the mounting hole 10 so that the groove opening is formed from the bottom of the groove 3. It protrudes to the side X. When the embedded portion of the tab terminal 4 is pressed into the mounting hole 10, the holding force of the tab terminal is increased.

FIG. 6 shows a third embodiment, in which the bottom surface 3a of the groove 3 is formed.
The mounting holes 10 ′ for press-fitting the tab terminals are formed to penetrate the groove opening side X and the side Y opposite to the groove opening side. This mounting hole 10 '
The tab terminal 4 is press-fitted into the groove 3, and the tip of the press-fitting side protrudes into the groove 3, and the other end of the tab terminal 4 protrudes to the opposite side Y. Projecting. Also in this case, the molten metal 6 'filled in the groove 3 and the tab terminal are bonded and fixed, and the conductive path and the tab terminal 4 can be conducted. As described above, the substrate 1
When projecting the tab terminal 4 downward with respect to the groove 3 opened on the upper surface, a locking projection 4h is provided at a portion of the tab terminal 4 projecting into the groove 3 as shown in FIG. When the tab terminals 4 are attached downward, the tab terminals 4 can be securely held, and the bonding area between the molten metal and the tab terminals 4 can be increased.

FIG. 7 shows a fourth embodiment in which the mounting holes 10 and 10 'of the second and third embodiments are provided in
The tab terminals 4 protrude from both upper and lower surfaces of the tab terminal 4.

FIG. 8 shows a fifth embodiment in which tab terminals 4 'are provided with projections 4b and 4k projecting from both upper and lower surfaces of the substrate 2, and an intermediate portion is provided with a groove 3 and an embedded portion 4 in a mounting hole 10.
The embedded portion 4b is provided with a locking projection 4h.
As in the third embodiment, a mounting hole 10 ′ penetrating from the bottom surface of the groove 3 of the upper surface opening to the lower surface of the substrate 2 is formed in the substrate 2. With respect to the groove 3 and the mounting hole 10 ′, the tab terminal 4 is attached to the mounting hole 1 with the protrusion 4 k as the lower end from the opening side of the groove 3.
It is press-fitted into 0 ', penetrated and attached.

FIG. 9 shows a sixth embodiment, in which the groove 3 'of the substrate 2 is formed.
Is formed in a semicircular cross section. As described above, when the groove 3 ′ is semicircular, the flowability of the molten metal 6 ′ poured into the groove 3 ′ is improved, and the molten metal 6 ′ is uniformly spread inside the groove 3 ′. And the adhesion to the film is improved. Further, the current density can be changed by changing the depth D and width W2 of the groove 3 'and changing the cross-sectional area of the groove 3'. Furthermore, if necessary, a flux may be applied to or coated on the inner surface of the groove 3 ′ in order to improve the wettability between the groove 3 ′ and the molten metal 6 ′. Furthermore, FIG.
As shown in the seventh embodiment, if the trajectory of the groove 3 is curved, the fluidity of the molten metal 6 ′ in the groove 3 can be improved.

In the circuit board 1 of the present invention, the grooves 3 and the tab terminals 4 can be freely provided on the substrate 2 without limitation, so that even a complicated electric circuit is constituted by one substrate. It is possible. However, due to the circuit design, it may not be possible to provide all the conductive paths 7 and the tab terminals 4 on one board. In such a case, FIG.
As shown in (B), a plurality of circuit boards 1 are used by laminating.

In this case, as shown in the eighth embodiment of FIG. 12, a through hole 11 is provided at a required portion of the substrate 2 and a tab terminal 4 projecting from another circuit board 1 to be laminated is formed in the through hole 11. It is made to penetrate with a gap between the inner peripheral surface.

FIG. 13 shows an electric junction box in which the above-mentioned circuit board 1 is accommodated. A plurality of circuit boards 1 are accommodated in a lower case 20 in a state of being stacked with a small gap. The lower end wall of the lower case 20 has a connector portion 2 protruding downward.
0a, and a terminal hole 20b is provided inside the connector portion 20a.
The tab terminal 4k projecting from the circuit board 1 is projected from the terminal hole 20b. On the other hand, an upper case 21 which covers the upper surface opening of the lower case 20 is provided with a connector portion 21a projecting upward.
A terminal hole 21b is bored inside a. The tab terminals 4b projecting from the circuit board 1 protrude from the terminal holes 21b.

As described above, when the circuit board 1 is stacked and accommodated in the electric junction box, the circuit board 1 is formed by burying the conductive path 7 in the insulating plate. There is no need to interpose a plate, and the electric connection box can be made thinner and smaller by that amount.

[0040]

As is apparent from the above description, the present invention has the following effects. First, the circuit board of the present invention is provided so as to be buried in the insulating plate with the conductive path exposed on the surface, and the tab terminal protrudes from a required position of the conductive path. In the case of stacking, there is no need for an insulating plate to be interposed. Further, since the tab terminals can be protruded from an arbitrary position of the conductive path, circuit design becomes easy, and the tab terminals can be arranged at a high density. Therefore, the cross-sectional area of the electric connection box can be reduced. As a result, it is possible to reduce the size of the electric connection box provided with a large number of branch connection portions such as a junction box, in addition to the reduction in thickness by eliminating the need for the insulating plate. Further, as compared with a conventional bus bar including a conductive path and a tab terminal, the strength is improved because it is held in a backing state by the substrate.

When the substrate is molded from a heat-resistant insulating resin, required circuit patterns can be formed easily and at low cost. Further, when the tab terminals are press-fitted into the grooves or the mounting holes provided in the substrate, the tab terminals can be easily mounted in the grooves.

When tab terminals are protruded from one side or both sides of the substrate, a connector can be attached to one or both sides of the electric connection box. You can use them properly. In particular, when the connectors are provided on both sides, the electrical junction box can be three-dimensionally used, and as a result, the electrical junction box can be downsized.

When solder is used as the molten metal to fill the groove for the conductive path, the conductive path can be formed easily at low cost and can be securely fixed to the tab terminal.

When the circuit board in which the insulating plate, the conductive path and the tab terminal are integrated is housed in the electric connection box, the electric connection box can be made thinner. In addition, since the insulating plate, which has been conventionally required, can be eliminated, the number of parts is reduced, and the number of steps for assembling to the electric junction box is reduced accordingly. Further, since tab terminals can be protruded from both sides of the circuit board, it is possible to provide connector portions on both sides of the electric connection box. In addition, when the circuit boards are accommodated in a stacked state, if the through holes are provided in the circuit boards to be stacked, the tab terminals can be protruded toward the outer surface of the case.

Further, in the circuit board of the present invention, a board is formed, tab terminals are attached to required portions of the board, and thereafter,
Since it only requires pouring of molten metal, large-sized press machines required for punching a conventional metal plate and large dies required for casting are not required, making it simple and inexpensive. You can do it.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a manufacturing process of a circuit board according to a first embodiment of the present invention.

FIGS. 2A and 2B are cross-sectional views of a state in which a tab terminal is attached to a groove in the state of FIG.

FIG. 3 is a perspective view of a circuit board according to the first embodiment.

FIGS. 4A and 4B are cross-sectional views of a tab terminal mounting portion of the circuit board of FIG.

FIG. 5 is a sectional view of a main part of a second embodiment.

FIG. 6 is a sectional view of a main part of a third embodiment.

FIG. 7 is a sectional view of a main part of a fourth embodiment.

FIG. 8 is a sectional view of a main part of a fifth embodiment.

FIG. 9 is a sectional view of a main part of a sixth embodiment.

FIG. 10 is a perspective view of a main part of a seventh embodiment.

FIGS. 11A and 11B are cross-sectional views illustrating a state in which circuit boards of the present invention are stacked and arranged.

FIG. 12 is a sectional view of a main part of an eighth embodiment.

FIG. 13 is a cross-sectional view showing a state where the circuit board of the present invention is housed in an electric junction box.

FIG. 14 is a perspective view of a conventional bus bar.

FIG. 15 is a development view of the bus bar of FIG. 14;

FIG. 16 is a perspective view of a conventional bus bar formed by casting.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Circuit board 2 Substrate 3 Groove 4 Tab terminal 4a Embedding part 4b, 4k Projecting part 6 Solder 7 Conductive path 8 Nozzle 10 Mounting hole 11 Through hole 20 Lower case 20a Connector 21 Upper case 21b Connector

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H05K 1/02 H02G 3/16 H05K 3/10

Claims (6)

(57) [Claims] 1. A circuit board housed inside an electric junction box having a connector portion provided on an outer surface thereof and projecting tab terminals from the connector portion, the circuit board being formed from a surface of a substrate made of a heat-resistant insulating material. The tab terminal made of a conductive plate which stands up from the inside of the groove and protrudes from the substrate surface, and the conductive material made of a conductive metal formed by filling the groove in a molten state and bonding and fixing the tab terminal. A circuit board, wherein a conductive circuit is formed on a substrate from a path, and tab terminals of the conductive circuit are projected to the connector portion. 2. The width of the groove is set to be the same as or slightly smaller than the thickness of the tab terminal, and the buried portion of the tab terminal is press-fitted into the groove and erected along the inner surface of the side wall of the groove. Claim 1
A circuit board according to claim 1. 3. It has a mounting hole opened on the inner surface of said groove,
2. The circuit board according to claim 1, wherein a buried portion of the tab terminal is press-fitted into the mounting hole to protrude from the groove. 4. The tab terminal protrudes from the opening side of the groove and the bottom side of the groove, and the tab terminal protrudes from both side surfaces of the board, and protrudes from the upper and lower connectors of the electric connection box. 5. The circuit board according to claim 4, wherein: 5. An electric junction box comprising a circuit board accommodating the circuit board according to claim 1. Description: 6. A circuit board, wherein a plurality of circuit boards are accommodated in a stacked state without interposing an insulating plate, and tab terminals protrude into the connector portion through through holes formed in the stacked circuit boards. 7. The electrical junction box according to 6.