JP2015201984A - circuit structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit deterioration of heat radiation performance.SOLUTION: A circuit structure 10 includes: electronic components 11, 12; a circuit board 15 on which the electronic components 11, 12 are mounted; a heat radiation member 20 which is overlapped with the circuit board 15 and radiates heat of the circuit board 15; and a spacer 27 disposed between the circuit board 15 and the heat radiation member 20. A gas suction passage 21 for suctioning a gas and thereby causing the circuit board 15 and the heat radiation member 20 to adhere to the spacer 27 is formed in the heat radiation member 20. In the spacer 27, suction holes 28 are formed in positions, which continue into the suction passage 21 and are covered by the circuit board 15, penetrating through the spacer 27.

Description

  The present invention relates to a circuit structure.

  2. Description of the Related Art Conventionally, a circuit structure in which a circuit board and a heat radiating member that radiates heat of the circuit board to the outside are overlaid is known. In this type of circuit structure, the circuit board is bonded onto the heat dissipation member with an adhesive.

  In the circuit structure of Patent Document 1, when a sheet-like body formed by weaving insulating fibers on an adhesive applied on a heat radiating member is stacked, the adhesive is almost uniformly applied to the entire sheet-like body. To Penetrate. A circuit body is piled up on this sheet-like body, and the circuit body is pressed on the heat radiating member side, thereby fixing the circuit body on the heat radiating member.

JP 2005-151617 A

  By the way, in patent document 1, when fixing a circuit body on a heat sink, the circuit body is pressed against the heat sink, but when pressing, it is not pressed against the entire surface of the circuit body with a uniform force. It's not easy. Therefore, the pressure generated in the adhesive via the circuit body becomes non-uniform, and a portion where the adhesive is not sufficiently bonded can occur. If there is a portion where the adhesive is not sufficiently bonded, peeling between the circuit body and the heat radiating plate may occur, and there is a concern that the heat dissipation performance may deteriorate.

  On the other hand, when the circuit board and the heat radiating member are attached, if the circuit board is sucked to the heat radiating member side, it is considered that the circuit board can be brought into close contact with the heat radiating member and relatively uniformly adhered. In this case, in order to suck the circuit board toward the heat radiating member, a suction path is provided in the heat radiating member, the circuit board is placed on the heat radiating member, and the circuit board is radiated using an external vacuum suction device or the like. Can be sucked to the side. However, in the configuration in which the suction path of the heat radiating member is directly covered with the circuit board, if air flows in between the circuit board and the heat radiating member, the circuit board cannot be uniformly adhered to the heat radiating member, and the heat dissipation performance is reduced. Is concerned.

  This invention is completed based on the above situations, Comprising: It aims at suppressing the fall of heat dissipation.

  The circuit structure of the present invention includes an electronic component, a circuit board on which the electronic component is mounted, a heat radiating member that is stacked on the circuit board and radiates heat from the circuit board, the circuit board, and the heat radiating member. A gas suction path for adhering the circuit board and the heat radiating member to the spacer by suction of gas is formed in the heat radiating member. Has a suction hole penetratingly formed at a position continuous with the suction path and at a position covered by the circuit board.

  According to this configuration, since the suction hole is formed through the spacer at a position continuous with the suction path and at a position covered by the circuit board, the suction hole can be used as a gas path during gas suction. By covering the suction hole with the circuit board, inflow of gas from the circuit board side can be suppressed as compared with the case where the circuit board covers the entire suction path. Thereby, since it becomes possible to make a circuit board and a heat radiating member closely_contact | adhere to a spacer at the time of suction | inhalation of gas, it becomes possible to suppress the fall of heat dissipation.

As an embodiment of the above configuration, the following configuration is preferable.
The circuit board includes a bus bar made of a plate-like metal, and the suction hole is covered with the bus bar.
In this way, since the suction hole is covered with the bus bar made of a plate-like metal, inflow of gas from the circuit board side can be suppressed as compared with the case where the suction hole is covered with the printed board.

The suction hole is superimposed on a portion where the direction of the suction path changes or a portion where the suction path branches.

The suction hole is formed at a position where the edge side of the circuit board covers.
In this way, the circuit board can be sucked uniformly.

-The spacer is formed with an accommodation hole for accommodating an affixing portion for adhering the circuit board and the heat dissipation member, and the accommodation hole and the suction hole are formed at different positions. Yes.
Thus, by forming the accommodation hole and the suction hole apart at different positions, a force acts on the affixing portion when the gas is sucked compared to the case where the accommodation hole and the suction hole are formed integrally or continuously. This makes it possible to suppress poor attachment due to the above.

-The said spacer is a sheet form.

  According to the present invention, it is possible to suppress a decrease in heat dissipation.

Sectional drawing which shows the circuit structure of embodiment Plan view showing printed circuit board Top view showing the bus bar Top view showing heat dissipation member Plan view showing spacers Plan view showing affixing part The top view which shows the positional relationship of a suction path and a suction hole in the state which accumulated the spacer on the heat radiating member The top view which shows the positional relationship of a suction hole and a bus bar in the state which accumulated the bus bar on the spacer

<Embodiment 1>
The first embodiment will be described with reference to FIGS.
The circuit structure 10 is disposed in a power supply path between a power source such as a battery of a vehicle and a load composed of on-vehicle electrical components such as a lamp and a wiper, and is used for, for example, a DC-DC converter or an inverter. it can. Hereinafter, the vertical direction and the horizontal direction will be described with reference to the directions in FIG.

(Circuit structure 10)
As shown in FIG. 1, the circuit component 10 is superposed on the electronic components 11 and 12, the circuit board 15 on which the electronic components 11 and 12 are mounted, and the circuit board 15 to dissipate heat from the circuit board 15. A member 20, a spacer 27 disposed between the circuit board 15 and the heat dissipation member 20, and a pasting portion 31 which is accommodated in the accommodation hole 27 </ b> A of the spacer 27 and attaches the circuit board 15 and the heat dissipation member 20. ing. FIG. 1 is a cross-sectional view of the circuit structure 10 at the position AA in FIG.

(Electronic parts 11, 12)
The electronic components 11 and 12 are each composed of a switching element (for example, a relay such as a mechanical relay or FET (Field Effect Transistor)), and has a box-shaped main body 13 and a lead terminal 14. The main body 13 has a rectangular parallelepiped shape, and lead terminals 14 are arranged on the bottom surface side thereof. Among the electronic components 11 and 12, the electronic component 11 has a plurality of lead terminals 14 projecting from the bottom surface side of the main body 13, and the electronic component 12 has a lead terminal 14 projecting from the side surface side of the main body 13 and the bottom surface of the main body 13. Lead terminals 14 are formed throughout. Each lead terminal 14 is connected to the conductive path of the circuit board 15 by, for example, reflow soldering.

(Circuit board 15)
The circuit board 15 has a rectangular shape, and is configured by bonding the printed board 16 and the bus bar board 17 using an adhesive member or the like (for example, an adhesive sheet or an adhesive). As shown in FIG. 2, the printed board 16 has a rectangular shape, and a conductive path (not shown) made of copper foil or the like is printed and wired on an insulating plate made of an insulating material. A plurality of through holes 16A for passing the lead terminals 14 of the electronic components 11 and 12 to the bus bar substrate 17 side and a plurality of boss portions 16B for screwing screws are formed in the printed circuit board 16.

  Each through hole 16 </ b> A has a rectangular shape and is arranged according to the positions of the electronic components 11 and 12. The boss portion 16B is arranged at four corners of the circuit board 15, and an insertion hole 16C through which the shaft portion of the screw is inserted is formed.

  As shown in FIG. 3, the bus bar substrate 17 includes a plurality of bus bars 18 in which a metal plate material such as copper or a copper alloy is shaped according to the shape of the conductive path. The plurality of bus bars 18 are arranged with a gap therebetween to form a bus bar substrate 17 having a rectangular shape as a whole. At the positions of the four corners of the bus bar substrate 17, through holes 17A communicating with the insertion holes 16C of the printed circuit board 16 are formed. The plurality of bus bars 18 include an L-shaped bus bar 18A on the same plane, a U-shaped bus bar 18B on the same plane, a linear bus bar 18C, and the like. In the bus bar 18A, the bus bar 18B, etc., a right-angled corner 19 is formed at a portion where the direction of the path changes.

  The lead terminal 14 of the electronic component 11 is soldered to the conductive path of the printed circuit board 16, and the other lead terminal 14 of the same electronic component 11 is soldered to the bus bar substrate 17 through the through hole 16A. In FIG. 2, a connection portion with the lead terminal 14 in the conductive path on the printed circuit board 16 is shown as a connection portion S.

(Heat dissipation member 20)
The heat radiating member 20 is made of a metal material having high thermal conductivity such as an aluminum alloy or a copper alloy, and has a rectangular shape larger than the circuit board 15 as shown in FIG. The flat upper surface 20A is provided with a suction path 21 that is connected to the external suction hole 23 and serves as a path for extracting air during vacuum suction, and a plurality of circular screw holes 25 are recessed. The external suction hole 23 is a hole for vacuuming air (gas), is circular, and has an external vacuum suction device (not shown) in the external suction port 23A (FIG. 1) at the lower end of the external suction hole 23. The circuit board 15 placed on the heat radiating member 20 can be sucked to the heat radiating member 20 side.

The suction path 21 sucks the internal gas in a state where the upper surface 20A side is covered and closed by the circuit board 15 and the spacer 27, and is recessed to the upper surface 20A of the heat radiating member 20 at a substantially constant depth. It forms a groove shape. The suction path 21 is stretched over the entire area where the circuit board 15 is arranged, and a plurality of path changing units 21A in which the direction of the path changes in a substantially orthogonal direction, and a plurality of paths that branch into a plurality of paths. And a branch portion 21B.
The screw hole 25 is formed at a position continuous with the through holes 16A and 17A of the circuit board 15, and the relative position between the circuit board 15 and the heat radiation member 20 is fixed by screwing from the circuit board 15 side.

(Spacer 27)
As shown in FIG. 5, the spacer 27 is a rectangular sheet with a small thickness, and includes eight (plural) rectangular accommodation holes 27 </ b> A in which the pasting portions 31 are accommodated, and a gas for sucking gas. A large number (a plurality) of rectangular suction holes 28 and four (a plurality of) circular insertion holes 27B through which the shaft portions of the screws are inserted are formed. The plurality of accommodation holes 27A form rectangular spaces that are separated from each other. The accommodation hole 27 </ b> A is arranged according to the position of the electronic components 11 and 12.

  The suction hole 28 is formed at a position that is continuous with the suction path 21 and is covered with the circuit board 15. Specifically, it is formed with a predetermined length (dimension in the major axis direction) with a width (dimension in the minor axis direction) that overlaps the entire width of the suction path 21 along the path of the suction path 21. The suction holes 28 are arranged on the edge of the bus bar 18, the corners 19, the ends of the bus bar 18 in the extending direction, and the like. The bus bar 18 covers the suction hole 28.

  The suction holes 28 overlap the heat radiating member 20 at locations such as the path changing portion 21A and the branching portion 21B where the direction of the suction path 21 changes. Further, the portion of the suction passage 21 where the suction holes 28 do not overlap is covered with the spacer 27 so as to be covered. The spacer 27 closes the suction path 21 to form a path for the sucked air.

  The spacer 27 is made of, for example, a thin plastic (synthetic resin), and has such a strength that it is not easily deformed by the force from the circuit board 15 and the heat radiating member 20 at the time of gas suction or the force at the time of screwing. The material which has is used.

(Paste part 31)
As shown in FIG. 6, the affixing portion 31 is a sheet-like member having adhesiveness and thermal conductivity, and has a rectangular shape slightly smaller than the accommodation hole 27A. As the affixing portion 31, for example, an insulating synthetic resin film coated on both surfaces with an insulating adhesive can be used. In the present embodiment, for example, an adhesive that mixes two liquids and solidifies at room temperature can be used. The electronic components 11 and 12 are disposed above the sticking portion 31, and the heat of the electronic components 11 and 12 can be radiated by the heat radiating member 20 through the sticking portion 31.

A method for manufacturing the circuit structure 10 will be described.
The spacer 27 is set at a predetermined position on the upper surface 20A of the heat dissipation member 20 (FIG. 7). Thereby, an air path from the external suction hole 23 to each suction hole 28 is formed.
Next, each sticking portion 31 is housed in each housing hole 27A, and the circuit board 15 formed by sticking the printed circuit board 16 and the bus bar substrate 17 together with an adhesive member is placed on the spacer 27 and the sticking portion 31. .
Then, the air in the suction path 21 is sucked from the external suction port 23A using an external vacuum suction device. When the air in the suction path 21 is sucked, the bottom surface of the bus bar 18 facing the space of the suction hole 28 is sucked toward the suction hole 28, and the bus bar substrate 17 and the heat dissipation member 20 are in close contact with the spacer 27.
Then, a solder paste is attached to the conductive path of the circuit board 15, and reflow soldering through a reflow furnace is performed, so that the electronic components 11, 12 and the like are mounted on the circuit board 15. Further, the screw is fixed to the boss portion 16 </ b> B and the screw hole 25 to fix the space between the circuit board 15 and the heat dissipation member 20. Thereby, the circuit structure 10 is formed (FIG. 1). The circuit structure 10 is housed in a case (not shown) and is arranged as an electrical connection box (not shown) on a route from the power source of the vehicle to the load.

  According to the present embodiment, since the suction hole 28 is formed through the circuit component 10 at a position continuous with the suction path 21 and at a position covered by the circuit board 15, the suction hole 28 is used for sucking gas. In addition, the circuit board 15 covers the suction holes 28, so that the inflow of gas from the circuit board 15 side can be suppressed as compared with the case where the circuit board 15 covers the entire suction path 21. Thereby, since it becomes possible to make the circuit board 15 and the heat radiating member 20 contact | adhere to the spacer 27 uniformly at the time of suction | inhalation of gas, it becomes possible to suppress the fall of heat dissipation.

The circuit board 15 includes a bus bar 18 made of a plate-like metal, and the suction hole 28 is covered with the bus bar 18.
In this case, since the suction hole 28 is covered with the bus bar 18 made of a plate-like metal, inflow of gas from the circuit board 15 side as compared with the case where the suction hole 28 is covered with the resin printed board 16. Can be suppressed.

Further, the suction hole 28 is overlapped with the path changing part 21A (part where the direction of the suction path changes) or the branch part 21B (part where the suction path branches) of the suction path 21.
In this way, it is possible to suppress the bias of the suction force when sucking from the suction hole 28.

The suction hole 28 is formed at a position where the edge side of the bus bar 18 covers.
In this way, the bus bar 18 can be sucked uniformly.

Further, the spacer 27 is formed with an accommodation hole 27A that accommodates a pasting portion 31 for adhering the circuit board 15 and the heat dissipation member 20, and the accommodation hole 27A and the suction hole 28 are separated from each other at different positions. Is formed.
In this way, by forming the accommodation hole 27A and the suction hole 28 apart at different positions, the pasting portion 31 at the time of sucking the gas, compared to the case where the accommodation hole 27A and the suction hole 28 are formed integrally or continuously. It is possible to suppress poor pasting due to the force acting on.

<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.
(1) The shape and number of the suction holes 28 are not limited to the above embodiment, and can be changed to various shapes and numbers. For example, the suction hole may be circular.

(2) In the above embodiment, the suction hole 28 is covered with the bus bar 18, but the suction hole may be covered with the printed board 16 and sucked from the bottom surface side of the printed board 16.

(3) In the above embodiment, the number of the spacers 27 is one (one). However, the present invention is not limited to this, and two (two) or more spacers may be stacked to form the suction holes.

(4) In the said embodiment, although the sticking part 31 had adhesiveness and heat conductivity, it is not restricted to this. Moreover, it is not restricted to the adhesive agent of the said embodiment, Various adhesive agents can be used. For example, a thermosetting or thermoplastic adhesive can be used. Moreover, you may use the heat conductive sheet which has adhesiveness, an adhesive tape, and an adhesive tape. Furthermore, a heat conductive sheet that can ensure adhesion between the circuit board 15 and the heat dissipation member 20 may be used even if there is no adhesive force and adhesive force.

(5) The electronic components 11 and 12 are not limited to relays, and various electronic components that generate heat when energized can be used.
(6) In the above embodiment, the circuit board 15 and the heat radiating member 20 are pasted by the pasting portion 31, and the circuit board 15 and the heat radiating member 20 are fixed by screwing with screws. However, the present invention is not limited to this, and only one of sticking by the sticking part 31 or screwing by screws may be performed.

DESCRIPTION OF SYMBOLS 10: Circuit structure 11, 12: Electronic component 15: Circuit board 17: Bus bar board 18: Bus bar 20: Heat radiating member 21: Suction path 27: Spacer 27A: Accommodating hole 28: Suction hole 31: Pasting part

Claims (6)

Electronic components,
A circuit board on which the electronic component is mounted;
A heat dissipating member that is superimposed on the circuit board and dissipates heat from the circuit board;
A spacer disposed between the circuit board and the heat dissipation member,
The heat radiating member is formed with a gas suction path for adhering the circuit board and the heat radiating member to the spacer by gas suction.
A circuit structure in which a suction hole is formed through the spacer at a position continuous with the suction path and at a position covered by the circuit board. The circuit board includes a bus bar made of a plate-shaped metal,
The circuit structure according to claim 1, wherein the suction hole is covered with the bus bar. The circuit structure according to claim 1 or 2, wherein the suction hole is overlapped with a portion where the direction of the suction path changes or a portion where the suction path branches. The circuit structure according to any one of claims 1 to 3, wherein the suction hole is formed at a position covered by an edge side of the circuit board. The spacer is formed with an accommodation hole for accommodating an affixing portion for adhering the circuit board and the heat dissipation member, and the accommodation hole and the suction hole are formed at different positions. The circuit structure as described in any one of Claims 1 thru | or 4. The circuit structure according to any one of claims 1 to 5, wherein the spacer has a sheet shape.

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