JP2010110170A - Circuit structure body and electric joint box - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit structure body and an electric joint box in which electronic components are made compact. <P>SOLUTION: The circuit structure body 10 includes a circuit board 11 with the electronic components 12 mounted on one surface thereof, and a bus bar 13 overlapped, through an insulating material 18, on the surface opposite to the surface on which the electronic components 12 of the circuit board 11 are mounted. The electronic components 12 are soldered to the bus bar 13 at one end thereof and has a terminal to be connected to the circuit board 11 in the other end thereof. An opening 14 is formed in the circuit board 11, and a connection area 16, which is overlapped and arranged on the opening 14 and connected to one end of the terminal 17D through soldering, is projectingly formed in the bus bar 13. A bus bar end face 13B, close to or abutting on the terminal face 14C of the opening 14 in the circuit board 11, is formed at the projecting end 16B projecting from the other area 16A in the connection area 16 of the bus bar 13. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a circuit structure and an electrical junction box.

  2. Description of the Related Art Conventionally, an electrical connection box for a vehicle in which a circuit component is housed in a waterproof case has been used. The circuit structure housed in the electrical junction box includes a circuit board on which electronic components are mounted on one surface and a bus bar bonded to the other surface via an insulating sheet. Terminals connected to the circuit board and the bus bar are provided (see, for example, Patent Document 1).

In the circuit structure described in Patent Document 1, an opening is provided in the circuit board, and a trapezoidal connection protrusion protruding from the opening is provided on the bus bar. The terminal extending to is connected by soldering.
JP 2006-5096 A

Incidentally, a vast number of parts are used in a vehicle to which such an electrical junction box is applied. In particular, electronic components are required to be small in size because the number of components is increasing due to the demand for higher functionality.
In the circuit configuration described in Patent Document 1, when the electronic component is downsized, the terminals connected to the electronic component, the connection protrusions to which the terminal is connected, and the like need to be downsized in accordance with the electronic component. is there.

  For example, the connection protrusion of the circuit structure can be formed by punching a predetermined region into a trapezoidal shape, but when the connection protrusion corresponding to the size of the electronic component is formed, the connection protrusion protrudes from the opening. Since the rising portion is steep, the interval between the rising portion of the bus bar connection projection and the opening of the circuit board is increased, resulting in a problem that a useless space is generated.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a circuit structure in which an electronic component is reduced in size.

  In order to solve the above-mentioned problems, the present invention provides a circuit board having an electronic component mounted on one surface, and a surface of the circuit board opposite to the surface on which the electronic component is mounted with an insulating material interposed therebetween. A bus bar, and the electronic component includes a terminal soldered to the bus bar at one end and a terminal connected to the circuit board at the other end. An area where the opening is formed and the bus bar overlaps with the opening protrudes from the other area, and is connected to one end of the terminal by soldering. Among them, a protruding end portion protruding from the other region is formed with a bus bar end surface that is close to or in contact with the end surface of the opening of the circuit board.

In the present invention, the protruding end portion of the connection area of the bus bar has a bus bar end face that is close to or in contact with the end face of the opening portion of the circuit board, for example, by press working. The distance between the connection region and the end face of the opening of the circuit board can be made smaller than that of the case. In other words, according to the present invention, even if a connection region having a size corresponding to the miniaturized electronic component is formed on the bus bar, the space between the connection region and the opening of the circuit board is not separated, so that no useless space is generated. .
As described above, according to the present invention, it is possible to provide a circuit structure in which electronic components are reduced in size.

The present invention may have the following configuration.
The opening of the circuit board has a comb-tooth portion formed in a comb-tooth shape, and the bus bar end surface is formed corresponding to the comb-tooth portion, and the comb-tooth end surface of the comb-tooth portion It is good also as a structure which adjoins or contact | abuts.
According to the above configuration, since the bus bar end surface formed corresponding to the comb tooth portion is close to or in contact with the comb tooth end surface of the comb tooth portion formed on the circuit board, The distance from the opening of the circuit board can be further reduced, which is preferable.

The electronic component is a switching element that performs switching of an in-vehicle electrical component, and the switching element includes a power terminal that is electrically connected to the in-vehicle electrical component, and a main body that covers the power terminal, The power terminal may be configured to be connected to the bus bar on the back surface of the main body of the switching element.
Since a large current flows through a power terminal that connects a switching element that performs switching of the in-vehicle electrical component and the in-vehicle electrical component, the temperature tends to be high.
According to the above configuration, since the power terminal through which a large current flows is connected to the bus bar on the back surface of the main body of the switching element, the contact area between the power terminal and the bus bar is wide. As a result, this configuration is preferable because heat dissipation is improved.

  ADVANTAGE OF THE INVENTION According to this invention, the circuit structure body and electrical connection box which aimed at size reduction of an electronic component can be provided.

<Embodiment 1>
An embodiment of the present invention will be described with reference to FIGS. The electrical junction box 40 of the present embodiment is obtained by housing the circuit component 10 according to the present invention 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, an electronic component 12 formed on one surface (upper surface) of the circuit board 11 and mounted on the control circuit 15, and the other surface of the circuit board 11. A bus bar 13 (power conductive path) made of a metal plate material disposed along the (lower surface) and connected to a power source (not shown) and the control circuit 15 is configured.

  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 control circuit 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 control circuit 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 control circuit 15 and the electronic component 12 are soldered by melting and cooling.

  In the present invention, as the electronic component 12, for example, a semiconductor switching element 12A, a mechanical relay switch 12B, or the like can be used. Among these, the semiconductor switching element 12A will be described.

  The semiconductor switching element 12A (hereinafter, also simply referred to as “switching element”) performs switching of on-vehicle electrical components, and includes a semiconductor chip (not shown) and a gate terminal 17A (control terminal) connected to the semiconductor chip. The drain terminal 17D (power terminal) and the source terminal (power terminal, not shown) are covered with a synthetic resin housing 17C (switching device main body) (see FIG. 3). . The drain terminal 17D is provided on the lower surface side of the housing 17C (the rear surface of the main body of the semiconductor switching element), and the gate terminal 17A is provided so as to protrude from the lower surface of the housing 17C toward the outside of the housing 17C.

  As shown in FIG. 1, the case 20 includes a frame 21 made of a synthetic resin and a heat radiating plate 22 made of metal (for example, aluminum alloy) having a high thermal conductivity. As shown in FIG. 2, the frame body 21 has a shape along the outer shape of the circuit board 11, and continuously surrounds the circuit board 11 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 that is disposed on the lower surface side of the circuit board 11 is accommodated in the accommodating space of the case 20. Then, the accommodation space 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.

  As shown in FIG. 4, the circuit board 11 of the present embodiment has a substantially rectangular opening 14 having a comb-shaped portion (comb portion 14B) on one side. Yes. And in this opening part 14, the connection area | region 16 of the bus-bar 13 is distribute | arranged so that the opening part 14 may adjoin or contact | abut.

The connection region 16 of the bus bar 13 is a region protruding from a region 16A (other region, hereinafter referred to as “first region 16A”) disposed on the lower side of the circuit board 11 and protruding into the opening 14. It is arranged.
The connection region 16 of the bus bar 13 is formed so as to protrude by cutting the bus bar 13 upward (circuit board 11 side). Further, the height of the connection region 16 is formed substantially the same as the height of the upper surface of the control circuit 15 (see FIG. 3). In particular, in the present embodiment, the upper surface of the connection region 16 is formed so as to be substantially the same height as the upper surface of the circuit board 11, and the amount of solder 23 applied to the upper surface of the control circuit 15 and the connection protrusion 16 of the circuit board 11. Thus, the mounting surface of the gate terminal 17A of the electronic component 12 and the mounting surface of the drain terminal 17D are formed to have substantially the same height.

  In the present embodiment, a cut surface is formed at an end portion of the connection region 16 excluding an end portion 16B protruding from the first region 16A (protruding end portion 16B). An end surface 16C (referred to as a “connection region end surface 16C”) at the end of the connection region 16 where the cut surface is formed is an end surface 14A formed on three sides other than the comb teeth portion 14B of the end surface of the opening 14. (Referred to as “first end surface 14A”).

The bus bar 13 is formed with a comb-tooth receiving portion 13A cut out in a square shape at a position corresponding to the comb-tooth portion 14B of the opening 14 (see FIG. 4). The comb tooth receiving portion 13A is formed at a position from the first region 16A of the bus bar 13 to the connection region 16 through the rising portion 16E to the connection region 16, and the comb tooth portion 14B of the opening 14 is formed. It can be fitted.
Of the end surfaces of the comb-tooth receiving portion 13A, the end surface 13B (bus bar end surface 13B) formed in the connection region 16 has a comb-tooth end surface 14C protruding into the opening portion 14 among the end surfaces of the comb-tooth portion 14B; It is arranged so as to come close to or abut.

  And among the electronic components 12 of the present embodiment, those connected to both the bus bar 13 and the control circuit 15 are connected to the bus bar 13 through the connection region 16 formed as described above. Connection of the switching element 12A will be described.

  First, the solder 23 is applied to the upper surface of the connection region 16 protruding into the control circuit 15 and the opening 14 as described above. As shown in FIG. 3, the gate terminal 17A is placed on the solder 23 applied to the control circuit 15, and the drain terminal 17D is placed on the solder 23 applied to the connection region 16. The Although not shown in FIG. 3, the source terminal is placed on the solder 23 applied to the bus bar 13. At this time, since the height of the control circuit 15 and the connection region 16 is formed to be substantially the same, the switching element 12A is stably placed on the circuit board 11. Subsequently, after the switching element 12A is placed on the circuit board 11 and heated in a high temperature furnace, it is cooled and the source terminal and the drain terminal 17D are soldered to the connection region 16 respectively. At the same time, the gate terminal 17A and the control circuit 15 are soldered.

Next, the operation and effect of this embodiment will be described.
According to this embodiment, the comb-tooth part 14B of the opening part 14 fits into the comb-tooth receiving part 13A of the bus bar 13 formed corresponding to the comb-tooth part 14B, and the comb-tooth end surface of the comb-tooth part 14B. Since 14A approaches or abuts on the bus bar end surface 13B, the distance between the connection region 16 of the bus bar 13 and the opening 14 of the circuit board 11 can be made smaller than that simply provided with the trapezoidal connection protrusion.
Therefore, according to the present embodiment, even if the connection region 16 having a size corresponding to the downsized electronic component 12 is formed on the bus bar 13, the distance between the connection region 16 and the opening 14 of the circuit board 11 is not separated. There is no wasted space. As a result, according to the present embodiment, it is possible to provide the circuit structure 10 in which the electronic component 12 is reduced in size.

  Furthermore, according to the present embodiment, the connection region end surface 16C of the connection region 16 of the bus bar 13 is close to or abuts with the first end surface 14A of the opening 14, so that the end portion of the connection region 16 other than the protruding end portion 16B. And the distance between the opening 14 of the circuit board 11 can be reduced.

  Further, according to the present embodiment, the drain terminal 17D, which is a power terminal through which a large current flows, is connected to the bus bar 13 on the lower surface of the housing 17C of the switching element 12A, so that the contact between the drain terminal 17D and the bus bar 13 is achieved. The area is increased and heat dissipation is improved.

  Further, according to the present embodiment, the connection region 16 protrudes to substantially the same height as the control circuit 15. For this reason, since the gate terminal 17A connected to the control circuit 15 and the drain terminal 17D connected to the bus bar 13 can be set to substantially the same height, the switching element 12A is stabilized. Thereby, since the soldering failure resulting from the switching element 12A moving during work can be prevented, the connection reliability of the circuit structure 10 is improved.

  In addition, when the bus bar 13 and the circuit board 11 are joined, the positioning of the bus bar 13 and the circuit board 11 is facilitated by fitting the connection region 16 into the opening 14, so that the workability during assembly is improved. .

<Embodiment 2>
The electrical junction box of Embodiment 2 will be described with reference to FIGS. The same reference numerals are used for the parts having the same names as those of the first embodiment described above, and redundant description of the structure, operation, and effect is omitted.

In the electrical junction box of the present embodiment, the shape of the opening 14 of the circuit board 11 and the shape of the connection region 16 of the bus bar 13 are different from those of the first embodiment.
In the present embodiment, as shown in FIG. 6, the circuit board 11 is formed with a substantially rectangular opening 14 formed by forming comb-tooth portions 14 </ b> B on two opposing sides.

  In the present embodiment, the connection region 16 of the bus bar 13 is formed by projecting the bus bar 13 toward the upper side (circuit board 11 side) by pressing, and can be fitted into the opening 14 of the circuit board 1. . As shown in FIG. 6, the connection region 16 is formed to have a substantially trapezoidal shape. On both sides of the connection region 16, a rising portion 16 </ b> E and a first region disposed below the circuit board 11. 16A is formed.

  A cut surface is formed at an end portion of the connection region 16 of the bus bar 13 excluding the two protruding end portions 16B. This cut surface is a connection region end surface 16 </ b> C that comes close to or abuts on the first end surface 14 </ b> A of the opening 14.

The bus bar 13 is formed with two comb tooth receiving portions 13A (four in total) cut into a square shape by pressing at positions corresponding to the comb tooth portions 14B of the opening 14 (FIG. 4). 6). The comb tooth receiving portion 13A is formed at a position from the first region 16A of the bus bar 13 to the connection region 16 through the rising portion 16E.
And also in this embodiment, as shown in FIG. 5, the comb-tooth part 14B of the opening part 14 fits in the comb-tooth receiving part 13A of the bus bar 13 formed corresponding to the comb-tooth part 14B, Since the comb tooth end surface 14A of the comb tooth portion 14B is close to or abuts on the bus bar end surface 13B, the distance between the connection region 16 of the bus bar 13 and the opening portion 14 of the circuit board 11 can be reduced.
Therefore, as in the first embodiment, even if the connection region 16 having a size corresponding to the downsized electronic component 12 is formed on the bus bar 13, the distance between the connection region 16 and the opening 14 of the circuit board 11 is not separated. There is no wasted space. As a result, according to the present embodiment, it is possible to provide the circuit structure 10 in which the electronic component 12 is reduced in size.

  Furthermore, also in the present embodiment, the connection region end surface 16C of the connection region 16 of the bus bar 13 is close to or abuts with the first end surface 14A of the opening 14, and therefore, the end of the connection region 16 other than the protruding end 16B The distance between the circuit board 11 and the opening 14 can also be reduced.

<Other embodiments>
The technical scope of the present invention is not limited by the above-described embodiments, and, for example, those described below are also included in the technical scope of the present invention.
(1) In the above embodiment, the opening 14 is formed with the comb-tooth-like comb-tooth portion 14B. However, for example, a slit is formed in the opening 14 and the connection region 16 corresponds to the slit. A slit having the shape described above may be formed, and the slit and the slit may be brought close to or in contact with each other.
(2) In the above embodiment, the present invention is applied to the switching element 12A. However, the present invention is not limited to this, and may be applied to other electronic components such as a mechanical relay switch 12B, a resistance element, and a capacitor.
(3) In the above embodiment, the height of the connection region 16 is the same as the upper surface of the circuit board 11, but is not limited to this. For example, the height may be the same as the upper surface of the control circuit 15. You may form in arbitrary height, if it protrudes from the bus-bar 13 in the opening part 14B.
(4) In the above embodiment, the circuit board and the bus bar are integrated through the insulating adhesive sheet, but may be integrated by resin molding.

The perspective view of the electrical junction box of Embodiment 1 Disassembled perspective view of electrical junction box Partially enlarged sectional view showing the connection structure between the control circuit and bus bar and the switching element The perspective view explaining the correspondence between the bus bar end face of the bus bar and the end face of the opening of the circuit board The partially expanded sectional view which shows the connection structure of the control circuit of Embodiment 2, and a bus-bar and semiconductor switching The perspective view explaining the correspondence between the bus bar end face of the bus bar and the end face of the opening of the circuit board

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Circuit structure 11 ... Circuit board 12 ... Electronic component 13 ... Bus bar 13B ... Bus bar end surface 14 ... Opening part 14C ... Comb tooth end surface (end surface of opening part)
16: Connection area 16A: First area (other areas)
16B ... Projecting end 17A ... Terminal (gate terminal)
17D ... Terminal (drain terminal)
15 ... Control circuit 23 ... Solder

Claims (4)

A circuit board with electronic components mounted on one side;
A circuit board comprising: a bus bar stacked with an insulating material on a surface opposite to a surface on which electronic components of the circuit board are mounted;
The electronic component includes a terminal having one end soldered to the bus bar and the other end connected to the circuit board,
An opening is formed in the circuit board,
Of the bus bar, the region that overlaps the opening protrudes from the other region, and is connected to one end of the terminal by soldering.
Of the connection area of the bus bar, the protruding end protruding from the other area
A circuit structure having a bus bar end face in contact with or in contact with an end face of the opening of the circuit board. The opening of the circuit board has a comb-tooth portion formed in a comb-tooth shape,
2. The circuit structure according to claim 1, wherein the end face of the bus bar is formed corresponding to the comb tooth portion and is close to or abuts on the end face of the comb tooth portion. The electronic component is a switching element that performs switching of the in-vehicle electrical component, and the switching element includes a power terminal that is electrically connected to the in-vehicle electrical component, and a main body that covers the power terminal,
The circuit structure according to claim 1, wherein the power terminal is connected to the bus bar on a back surface of the main body of the switching element. An electrical junction box, wherein the circuit component according to any one of claims 1 to 3 is accommodated in a case.

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