JP2006005107A - Circuit structure body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit structure body which is superior in connection reliability of a bus bar and a circuit pattern. <P>SOLUTION: In the circuit structure body 10, the circuit pattern (not illustrated) is formed on one face of a circuit board 11. The bus bars 13 which are electrically connected to the circuit pattern are fitted to the other face of the circuit board 11. A connection protrusion 16 is formed on the bus bar 13 so that it rises toward one face of the circuit board 11. The connection protrusion 16 is inserted into a through hole 14 formed in the circuit board 11 and is securely soldered with a land 15 formed on the inner wall of the through hole 14 and a periphery of an opening. Thus, connection reliability of the circuit structure body 10 can be improved. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a circuit structure.

  Conventionally, in order to distribute power from an in-vehicle power supply to various electrical components, a control element and a switching element are mounted on a circuit pattern formed on one surface of the circuit board, and on the other surface of the circuit board, An electric junction box is used in which a circuit structure in which a bus bar that is electrically connected to a switching element and that constitutes a power circuit is bonded via an insulating layer is housed in a waterproof case (see Patent Document 1). ).

In the above circuit structure, the circuit pattern (not shown) formed on one surface of the circuit board 1 and the bus bar 2 attached to the other surface via the insulating layer 6 are as follows. Connected. As shown in FIG. 12, a through hole 3 is formed in the circuit board 1, and metal plating electrically connected to a circuit pattern (not shown) is formed around the inner wall and the opening of the through hole 3. 4 is given. After bonding the circuit board 1 and the bus bar 2, the solder 5 is filled into the through hole 3 from the opening. When the solder 5 is filled up to the bottom of the through hole 3, the bus bar 2 exposed at the bottom and the metal plating 4 formed on the inner wall of the through hole 3 are electrically connected via the solder 5, Thus, the bus bar 2 and the circuit pattern (not shown) are electrically connected.
JP 2003-164039 A

  However, according to the method of filling the solder 5 from the opening of the through hole 3 as described above, the melted solder 5 may not be filled to the bottom of the through hole 3 due to air remaining in the through hole 3 or the like. Then, the bus bar 2 and the circuit pattern (not shown) are not soldered, and the connection reliability between the bus bar 2 and the circuit pattern (not shown) may be lowered (see FIG. 13).

  The present invention has been completed based on the above circumstances, and an object thereof is to provide a circuit structure excellent in connection reliability between a bus bar and a circuit pattern.

  As means for achieving the above object, the invention of claim 1 is characterized in that a circuit pattern is formed on one surface of the circuit board, and the circuit pattern and the electric circuit are electrically connected to the other surface of the circuit board. The bus bar is connected to the bus bar, the bus bar is formed with a connection protrusion so as to rise toward one surface of the circuit board, the connection protrusion, It is characterized by being soldered to the circuit pattern or electronic component provided on one surface of the circuit board.

  According to a second aspect of the present invention, in the first aspect of the present invention, a through hole is formed in the circuit board, and the connection projection is inserted into the through hole.

  According to a third aspect of the present invention, in the first aspect of the present invention, the connection protrusion is formed by cutting and raising a part of the bus bar, and a through hole formed by the cutting and raising coincides with the through hole. It is characterized by being.

  According to a fourth aspect of the present invention, in the first aspect, the connection protrusion is provided to face a side edge of the circuit board, and the connection protrusion is formed on the side edge of the circuit board. A cutout portion for accommodating the portion is formed.

<Invention of Claim 1>
Since the connection protrusion is formed so as to rise toward one surface of the circuit board, the circuit pattern formed on one surface of the circuit board and the electronic component mounted on the circuit pattern are provided here. , Can be soldered more reliably. Thereby, the connection reliability between a bus bar and a circuit pattern can be improved.

<Invention of Claim 2>
According to the second aspect of the present invention, since the bus bar and the circuit board can be positioned by inserting the connection protrusion into the through hole, the circuit board and the bus bar can be easily positioned relative to each other. be able to.

<Invention of Claim 3>
Conventionally, for example, X-ray inspection has been performed for inspection of defective soldering between a bus bar and a circuit board. This is because the soldering failure between the bus bar and the circuit board occurs inside the through hole, and the soldering failure location cannot be directly inspected visually. In addition, there are often a plurality of connection points between the bus bar and the circuit board in one circuit board, and X-ray inspection is performed on these, so that the inspection process for defective soldering is complicated. It was.

  According to the invention of claim 3, the inside of the through hole is directly observed from the through hole, and whether or not the solder is filled in the through hole, that is, whether or not there is a soldering defect directly in the through hole. I can confirm. For this reason, it is not necessary to perform an X-ray inspection or the like when inspecting a soldering defect between the bus bar and the circuit board, so that the inspection process can be greatly simplified.

<Invention of Claim 4>
According to the invention of claim 4, the notch is open toward the outside of the circuit board. For this reason, an air escape path is secured, so that the solder can be filled up to the bottom of the notch. Thereby, a connection protrusion and a circuit pattern or an electronic component can be soldered reliably. Thus, according to the invention of claim 4, connection reliability of the circuit structure can be improved.

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIGS. The electrical junction box 40 of this embodiment is one in which the circuit structure 10 according to the present invention is accommodated in a case 20 having a heat dissipation function (see FIG. 1).

  As shown in FIG. 2, the circuit structure 10 includes a circuit board 11 and an electronic component 12 (for example, a mechanical relay) formed on one surface (upper surface) of the circuit board 11 and mounted on a circuit pattern (not shown). A switch, a switching member such as a semiconductor switching element, a control element, and the like) and the other surface (lower surface) of the circuit board 11 are connected to a power source (not shown) and a circuit pattern (not shown). It is comprised from the bus-bar 13 (electrical power conductive path) which consists of metal plates.

  The circuit board 11 is provided with through holes 14 penetrating up and down the circuit board 11 at appropriate positions (positions where electronic components are not disposed). Around the inner wall and the opening of the through hole 14, The land 15 is formed by performing copper plating, and the land 15 is electrically connected to a circuit pattern (not shown).

  The circuit board 11 and the bus bar 13 are integrated through a thin adhesive sheet 18 having insulating properties. The circuit board 11 and the bus bar 13 are joined in a step before the electronic component 12 is mounted. At this time, the electronic component 12 is not mounted on the circuit board 11, so that the surface of the circuit board 11 is almost the same. It is performed by pressing uniformly with a press or the like over the entire area. As a result, the adhesive sheet 18 can be firmly adhered to the lower surface (back surface) of the circuit board 11 and the upper surface (front surface) of the bus bar 13, and the circuit board 11 and the bus bar 13 are firmly bonded by such full pressing. It is joined to.

  The electronic component 12 is mounted on the land portion 15 of the circuit board 11 by reflow soldering. In this reflow soldering, the solder 23 is applied in advance to the position where the electronic component 12 is mounted on the land portion 15, the electronic component 12 is placed on the solder 23, and the solder 23 is heated by heating in a high-temperature furnace. The land portion 15 and the electronic component 12 are soldered by melting and cooling.

  The case 20 includes a synthetic resin frame body 21 and a metal (for example, aluminum alloy) heat dissipation plate 22 having a high thermal conductivity. The frame body 21 has a shape along the outer shape of the circuit board 11, and surrounds the circuit board 11 continuously without any breaks over the entire circumference. The heat radiating plate 22 has substantially the same shape as the outer shape of the frame body 21, and is assembled to the frame body 21 from the lower surface side. Assembling so that the lower surface of the frame body 21 and the upper surface of the heat radiating plate 22 are in contact with each other, and screwing and tightening a screw penetrating the heat radiating plate 22 from below to the lower surface of the frame body 21, Are integrated to form the case 20. A housing space (not shown) opened to the upper surface side is formed inside the case 20 by the heat radiating plate 22 and the frame body 21 rising along the outer periphery of the heat radiating plate 22.

  The assembly of the case 20 is performed in parallel with the assembly of the circuit structure 10 to the case 20. That is, an insulating adhesive made of an epoxy resin is applied to the upper surface of the heat radiating plate 22, and the circuit component 10 integrated with the frame body 21 is overlaid on the upper surface of the heat radiating plate 22. At this time, the adhesive is bonded to the lower surface (back surface) of the bus bar 13 and the upper surface (front surface) of the heat sink 22 by pressing the circuit board 11 with a press or the like using a jig (not shown). An insulating layer (not shown) is formed between the bus bar 13 and the heat sink 22. Furthermore, the heat sink 22 and the frame body 21 are fixed by screwing screws into the heat sink 22 and the frame body 21. In addition, watertightness is ensured between the frame body 21 and the heat sink 22 by applying a sealing agent (not shown).

  In the state where the case 20 and the circuit structure 10 are assembled in this manner, a portion of the bus bar 13 arranged on the lower surface side of the circuit board 11 is accommodated in an accommodation space (not shown) of the case 20. . The accommodation space (not shown) is filled with a potting agent (not shown) as a waterproof means, and the bus bar 13 is embedded in the potting agent (not shown).

  A cover 30 is assembled to the frame body 21 from above, and the cover 30 covers and conceals the upper surface side of the circuit structure 10. Further, a front connector housing 31 surrounding the terminal portion of the bus bar 13 protruding forward from the front edge of the cover 30 is assembled to the front end portion of the cover 30, and a fuse box 32 is attached to the rear end edge portion of the cover 30. In this fuse box 32, a rear connector housing 33 for housing a terminal portion protruding upward from the rear end edge of the cover 30 is assembled. Thus, the electronic junction box 40 of this embodiment is comprised.

  Now, as shown in FIG. 3, the bus bar 13 has a part of the bus bar 13 at a position corresponding to the through hole 14 when the bus bar 13 is assembled from the lower side of the circuit board 11 to the normal position. A substantially rectangular connection protrusion 16 is formed by cutting and raising the upper surface (one surface side of the circuit board). The connection protrusion 16 can be formed by bending the bus bar 13 by pressing, or by knocking the bus bar 13 by pressing. The end of the connection protrusion 16 is formed at substantially the same height as the land portion 15 formed on the upper surface of the circuit board 11 (one surface of the circuit board). The thickness dimension and the width dimension of the connection protrusion 16 are shorter than the diameter of the through hole 14, and the connection protrusion 16 is configured to be inserted into the through hole 14.

  The bus bar 13 is assembled from the lower side of the circuit board 11, and a connection protrusion 16 is inserted from the lower side at a substantially central portion in the through hole 14 (see FIG. 3). Thereby, the bus bar 13 and the circuit board 11 are positioned in the front-rear and left-right directions. In this through hole 14, solder 23 is filled up to the bottom of the through hole 14 (the other surface side of the circuit board), and the bus bar 13, the connection protrusion 16, and the land portion 15 are soldered. (See FIG. 4).

  Further, the bus bar 13 is formed with a punch hole 17 where the connection protrusion 16 is cut and raised. The through hole 17 is arranged at a position coincident with the through hole 14, and the solder 23 filled in the through hole 14 can be visually recognized from the through hole 17.

  As described above, according to the first embodiment, the connection protrusion 16 is formed so as to rise toward the upper surface of the circuit board 11, and therefore, the connection protrusion 16 and the land formed on the upper surface of the circuit board 11. The part 15 can be soldered more reliably. Thereby, the connection reliability between the bus bar 13 and a circuit pattern (not shown) can be improved.

  Further, since the bus bar 13 and the circuit board 11 can be positioned by inserting the connection protrusion 16 into the through hole 14, the circuit board 11 and the bus bar 13 can be easily positioned relative to each other. Can do.

  Further, according to the first embodiment, the inside of the through hole 14 can be directly visually confirmed from the punched hole 17 formed in the bus bar 13. For this reason, it can be directly visually inspected whether the solder 23 is filled in the through hole 14 and the bus bar 13 and the circuit board 11 are well soldered. Thus, since the X-ray inspection or the like does not have to be performed in the continuity inspection process between the bus bar 13 and the circuit pattern (not shown), the inspection process can be simplified.

<Embodiment 2>
5 to 7 show Embodiment 2 of the present invention.
In the second embodiment, the connection structure between the land portion 15 and the connection protrusion 16 is different from that of the first embodiment. Since other configurations are the same as those of the first embodiment, the same configurations are denoted by the same reference numerals, and descriptions of structures, operations, and effects are omitted.

  As shown in FIG. 5, a notch 19 formed by cutting the circuit board 11 into a substantially rectangular shape when viewed from above is formed on the side edge of the upper surface of the circuit board 11. The length dimension in the front-rear direction of the notch 19 is larger than the thickness dimension of the connection protrusion 16, and the length in the left-right direction of the notch 19 is the width of the connection protrusion 16. The connection protrusion 16 can be accommodated in the notch 19.

  The inner wall of the cutout portion 19 is plated with copper, and the periphery of the cutout portion 19 on the upper surface of the circuit board 11 is also plated, so that the land portion 15 has a circuit pattern (not shown). And in an electrically connected state. The connection protrusion 16 is accommodated in the notch 19. The notch 19 is filled with solder 23 up to the bottom of the notch 19 (the other surface side of the circuit board 11), and the bus bar 13, the connection protrusion 16, and the land 15 are soldered. (See FIGS. 6 and 7).

  According to the second embodiment, the notch 19 is open toward the outside of the circuit board 11. For this reason, an air escape path is secured, so that the solder 23 can be filled up to the bottom of the notch 19. Thereby, since the connection protrusion 16 and a circuit pattern (not shown) can be soldered reliably, the connection reliability of the circuit structure 10 can be improved.

<Embodiment 3>
8 and 9 show Embodiment 3 of the present invention.
In the third embodiment, the connection structure between the land portion 15 and the connection protrusion 16 is different from that of the first embodiment. Since other configurations are the same as those of the first embodiment, the same configurations are denoted by the same reference numerals, and descriptions of structures, operations, and effects are omitted.

  As shown in FIG. 8, a notch 19 formed by cutting the circuit board 11 into a substantially rectangular shape when viewed from above is formed on the side edge of the upper surface of the circuit board 11. The length dimension in the front-rear direction of the notch 19 is larger than the thickness dimension of the connection protrusion 16, and the length in the left-right direction of the notch 19 is the width of the connection protrusion 16. The connection protrusion 16 can be accommodated in the notch 19.

  The inner wall of the cutout portion 19 is plated with copper, and the periphery of the cutout portion 19 on the upper surface of the circuit board 11 is also plated, so that the land portion 15 has a circuit pattern (not shown). And in an electrically connected state.

  As shown in FIG. 8, the second bus bar 24 is disposed from the outer region of the circuit board 11 toward the notch 19, and the connection protrusion 16 formed at the end of the second bus bar 24. Is housed in the notch 19. Although not shown in detail, the second bus bar 24 is attached to the lower surface of the circuit board 11 (the other surface side of the circuit board 11). There is a gap between the connection protrusion 16 and the inner wall of the notch 19. In this gap, the solder 23 is filled up to the bottom of the cutout portion 19 (the other surface side of the circuit board 11), and the second bus bar 24, the connection projection 16 and the land portion 15 are soldered. (See FIG. 9). The solder 23 filled in the notch 19 is visible from the gap between the connection protrusion 16 and the notch 19.

  According to the third embodiment, the gap between the second bus bar 24 and the inner wall of the cutout portion 19 is viewed from below (the other surface side of the circuit board 11), so that the inside of the cutout portion 19 is directly visually observed. it can. For this reason, it can be directly visually inspected whether the solder 23 is filled in the notch 19 and the second bus bar 24 and the circuit board 11 are well soldered. Thus, since the X-ray inspection or the like does not have to be performed in the continuity inspection process between the second bus bar 24 and the circuit pattern (not shown), the inspection process can be simplified.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.

  (1) In the present embodiment, the connection protrusion 16 is soldered to the land portion 15, but is not limited thereto, and the connection protrusion 16 and the terminal of the electronic component 12 may be soldered.

  (2) In the first embodiment, the shape of the through hole 14 is circular when viewed from above, but is not limited thereto, and may be any shape such as an oval, an ellipse, a rectangle, or a rectangle when viewed from above. .

  (3) In Embodiment 2, the shape of the notch 19 is rectangular when viewed from above, but is not limited thereto, and may be any shape such as semicircular and semielliptical when viewed from above.

  (4) In the present embodiment, the shape of the connection protrusion 16 is substantially rectangular. However, the shape is not limited to this, and an arbitrary shape such as a semicircle or a triangle may be taken.

  (5) In the present embodiment, the connection protrusion 16 is formed by being cut and raised from the bus bar 13 by press working. However, the present invention is not limited to this, and the press bar working from the bus bar 13 to one surface of the circuit board. It may be formed by bulging (see FIG. 10). Alternatively, a pin or the like may be driven into the bus bar 13 and the pin or the like may be used as a connection protrusion (see FIG. 11).

The perspective view of the electrical-connection box concerning Embodiment 1 of the present invention. Similarly exploded perspective view of electrical junction box The partial perspective view which shows the state by which the connection protrusion cut and raised from the bus bar was inserted in the through hole similarly formed in the circuit board Similarly, a partially enlarged sectional view showing a state in which the connection protrusion and the land are soldered. The circuit structure which concerns on Embodiment 2 of this invention WHEREIN: The partial expansion perspective view which shows arrangement | positioning with a land part and a connection protrusion. Similarly, a partially enlarged sectional view showing a state in which the connection protrusion and the land are soldered. Similarly, a partially enlarged plan view showing a state where the connection protrusion and the land are soldered The circuit structure which concerns on Embodiment 3 of this invention WHEREIN: The partially expanded perspective view which shows arrangement | positioning with a land part and a connection protrusion. Similarly, a partially enlarged sectional view showing a state in which the connection protrusion and the land are soldered. The partially expanded sectional view which shows the state by which the connection protrusion and the land part were soldered in the circuit structure which concerns on other embodiment (5). The partially expanded sectional view which shows the state by which the connection protrusion and the land part were soldered in the circuit structure which concerns on other embodiment (5). Partially enlarged sectional view showing a state in which the bus bar and the land portion are well soldered in the conventional example Partially enlarged sectional view showing a state of poor soldering between the bus bar and the land portion in the conventional example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Circuit structure 11 ... Circuit board 12 ... Electronic component 13 ... Bus bar 14 ... Through-hole 15 ... Land part 16 ... Connection protrusion 17 ... Opening hole 19 ... Notch part 24 ... 2nd bus bar

Claims (4)

A circuit pattern is formed on one side of the circuit board, and a bus bar electrically connected to the circuit pattern is attached to the other side of the circuit board,
The bus bar has a connection protrusion formed so as to rise toward one surface of the circuit board,
The connection protrusion is soldered to the circuit pattern or electronic component provided on one surface of the circuit board. A through hole is formed in the circuit board,
The circuit structure according to claim 1, wherein the connection protrusion is inserted into the through hole. 3. The circuit structure according to claim 2, wherein the connection protrusion is formed by cutting and raising a part of the bus bar, and a through hole formed by the cutting and raising coincides with the through hole. The connection protrusion is provided to face the side edge of the circuit board,
The circuit structure according to claim 1, wherein a cutout portion for accommodating the connection protrusion is formed on a side edge of the circuit board.

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