JP2016119797A - Circuit structure and electric connection box - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress reduction in heat radiation property.SOLUTION: A circuit structure 20 comprises: a circuit board 21 having a conducting path and on which an electronic component 26 is mounted; a heat radiation member 28 overlapped with the circuit board 21 to radiate heat of the circuit board 21, and that has a protrusion 35 protruded toward a side of the circuit board 21; a spacer 40 arranged between the circuit board 21 and the heat radiation member 28, and penetrated with an insertion hole 41 into which the protrusion 35 is inserted; and a heat transfer part 47 arranged between the circuit board 21 and the protrusion 35 in the insertion hole 41 to propagate the heat of the circuit board 21 to the protrusion 35.SELECTED DRAWING: Figure 4

Description

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

  2. Description of the Related Art Conventionally, a circuit structure in which a circuit board and a heat radiating member that radiates heat from 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, the circuit body is pressed against the heat radiating member when the circuit body is fixed on the heat radiating plate. During the pressing, the circuit board and the heat radiating member are held at a constant interval. Otherwise, there is a concern that, for example, the pressure generated in the adhesive through the circuit body becomes non-uniform, and a portion where the adhesive is not sufficiently bonded is generated.

Here, if a spacer is provided between the circuit board and the heat radiating member, the space between the circuit board and the heat radiating member can be maintained at a constant interval. The heat conductivity with the heat radiating member is deteriorated, and there is a concern that the heat radiating property is lowered.
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 has a conductive path, a circuit board on which electronic components are mounted, and a protrusion that is superimposed on the circuit board to dissipate heat from the circuit board and protrudes toward the circuit board A heat dissipating member, a spacer that is disposed between the circuit board and the heat dissipating member, and is formed through an insertion hole through which the protrusion is inserted, and the circuit board and the protrusion in the insertion hole. And a heat transfer portion that is disposed between the heat transfer portion and transfers heat of the circuit board to the protrusion.

  According to the present invention, the heat of the circuit board can be radiated by the heat radiating member through the heat transfer portion and the protrusion. Here, since the heat transfer part has a thickness dimension smaller than the interval between the circuit board and the heat dissipation member, the heat transfer part is radiated by the amount of the protrusion inserted into the insertion hole. The thermal conductivity between the members can be increased. Thereby, even if a spacer is provided between the circuit board and the heat dissipation member, it is possible to suppress a decrease in heat dissipation. Further, by using the spacer, it is possible to eliminate the use of a jig for maintaining a constant distance between the circuit board and the heat radiating member, so that the manufacturing cost can be reduced.

The embodiments of the present invention may be the following modes.
-The said heat-transfer part has adhesiveness which adhere | attaches between the said circuit board and the said protrusion.
When the area to which the adhesive is applied is large, it takes time to apply the adhesive, and there is a problem that the adhesive starts to harden during the application of the adhesive and a portion where the adhesive is not sufficiently bonded occurs. According to this configuration, by bonding between the circuit board and the protrusion with an adhesive, the area for applying the adhesive can be reduced compared to the case of bonding other than the area of the protrusion. Application time can be reduced. Therefore, it is possible to suppress a sticking failure between the circuit board and the heat radiating member due to the adhesive being cured during application.

-The said heat-transfer part uses what hardens | cures at normal temperature.
If a thermosetting adhesive that cures by heating is used, the adhesive can be prevented from curing during application of the adhesive, but the equipment cost for heating the adhesive increases and the adhesive dissipates heat. If the coating is applied to the entire surface of the member, the amount of adhesive applied increases, which raises the problem of increased material costs. According to this structure, material cost can be reduced by using the heat-transfer part hardened | cured at normal temperature cheaper than a thermosetting adhesive.

The circuit board and the heat radiating member are screwed.
If it does in this way, between a circuit board and a heat dissipation member can be firmly fixed with a screw, receiving the force at the time of screwing with a spacer.

The electronic component is mounted at a position that overlaps at least a part of the heat transfer section on the circuit board.
If it does in this way, the heat of an electronic component can be radiated via a heat-transfer part and a projection.

-The said protrusion is inserted in the said insertion hole.
If it does in this way, positioning of a spacer and a heat radiating member can be performed using a projection.

-It is set as the electrical junction box provided with the said circuit structure.

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

The perspective view which shows the electrical-connection box of Embodiment 1. Top view showing the electrical junction box AA sectional view of FIG. The figure which expanded the part of the vicinity of the protrusion of FIG. BB sectional view of FIG. Plan view showing circuit board Perspective view showing spacer Plan view showing spacers Bottom view showing spacer A perspective view showing a heat dissipation member Top view showing heat dissipation member The top view which shows the state in which the spacer was mounted in the heat radiating member The top view which shows the state by which the circuit board was mounted from the state of FIG. The top view which shows the state in which the spacer was mounted in the heat radiating member of Embodiment 2.

<Embodiment 1>
The first embodiment will be described with reference to FIGS.
The electric junction box 10 is arranged in a power supply path between a power source such as a battery of a vehicle and a load composed of an on-vehicle electrical component such as a lamp and a wiper or a motor, and is used for, for example, a DC-DC converter or an inverter. be able to. Hereinafter, the vertical direction will be described with reference to the direction of FIG.

(Electric junction box 10)
As shown in FIGS. 1 and 3, the electrical connection box 10 includes a circuit structure 20, a shield cover 11 that covers the upper surface of the circuit structure 20, and a plurality of connector portions 17 </ b> A and 17 </ b> B. The shield cover 11 is formed by punching and bending a plate-like metal made of aluminum or the like, and a fixed piece 12 is bent in an L shape at the lower end. The shield 12 is connected to the ground via the heat radiating member 28 by screwing the fixing piece 12 to the boss portion 34 of the heat radiating member 28 with the screw 13. External connection portions 15 are formed at corners of the electrical connection box 10. The external connection portion 15 accommodates a terminal portion 25 for connecting to an external terminal inside the synthetic resin housing portion 16.

(Circuit structure 20)
As shown in FIG. 3, the circuit component 20 includes a circuit board 21 on which the electronic component 26 is mounted, a heat radiation member 28 that is superposed on the circuit board 21 and radiates heat from the circuit board 21, and the circuit board 21 and the heat radiation. And a spacer 40 disposed between the member 28 and the member 28.

(Circuit board 21)
As shown in FIG. 6, the circuit board 21 has a rectangular shape, and includes a plurality of screw holes 22 for screwing screws and positioning holes 23 for positioning the circuit board 21 with respect to the spacer 40. A plurality of through holes are formed at positions near the peripheral edge of the circuit board 21. The circuit board 21 is configured by bonding a printed board 21A and a bus bar board 21B using an adhesive member (for example, an adhesive sheet or an adhesive). The printed circuit board 21A has a rectangular shape, and a conductive path (not shown) made of copper foil is printed and wired on an insulating plate made of an insulating material. The bus bar substrate 21 </ b> B is made of a plurality of bus bars that are made of a metal plate material such as copper or copper alloy according to the shape of the conductive path and are spaced from each other. Connector terminals 24 and terminal portions 25 are formed at the ends of the bus bar substrate 21B.

  A plurality of electronic components 26 (see FIG. 3) are mounted on the circuit board 21, and are more heat-generating components such as switching elements (for example, FET (Field Effect Transistor)), resistors, coils, and the like, and relatively higher than the high-heat-generating components. And low heat-generating components such as capacitors that do not generate heat. The high heat generating component has a main body that generates heat and a plurality of lead terminals led out from the main body. The lead terminals of the electronic component 26 are soldered to the conductive path of the printed board 21A and the bus bar board 21B. The electronic component 26 is not limited to a lead terminal from which the lead terminal is derived, and may be a leadless terminal having no lead terminal. For example, all terminals of the electronic component (such as an FET) are connected to the main body. It may be formed on the surface.

(Heat dissipation member 28)
The heat dissipating member 28 is made of metal such as aluminum or aluminum alloy formed by aluminum die casting, for example, and as shown in FIG. 10, a mounting portion 29 on which the spacer 40 is mounted, and a mounting portion 29 The peripheral wall part 33 which protrudes upward from the peripheral part of this, and the radiation fin 37 provided in the bottom face side of the mounting part 29 are provided.

  The mounting portion 29 includes a flat portion 30 having a flat upper surface, and a plurality of protrusions 35 (14 in the present embodiment) protruding upward from the flat portion 30 in a circular shape. A plurality of screw holes 31A for screwing, a plurality of positioning holes 31B for positioning the spacer 40, and a relief recess 31C are formed in the plane portion 30. The screw hole 31 </ b> A is formed at a position on the edge side of the flat portion 30. An end portion of a terminal (not shown) inserted through the through hole of the circuit board 21 is disposed in the escape recess 31C. Concave portions 32 </ b> A and 32 </ b> B are formed in the plane portion 30 according to the positions of the coil (not shown) and the terminal portion 25.

  The plurality of protrusions 35 have a perfect circular columnar shape (disc shape), and are arranged in a plurality of rows at equal intervals (intervals in the left-right direction in FIG. 11) as shown in FIG. In addition, in each row, a plurality of protrusions 35 are arranged at equal intervals (intervals in the vertical direction in FIG. 11). Since the protrusions 35 near the screw holes 31A are arranged at a predetermined distance from the screw holes 31A, the rows of the protrusions 35 are shifted from the rows of the other protrusions 35. Is arranged. The outer periphery of the projection 35 is orthogonal to the plane portion 30, and the height of the projection 35 is smaller than the vertical dimension of the insertion hole 41 of the spacer 40 described later. The plurality of protrusions 35 are arranged so that part or all of the main body of the electronic component 26 that is a high heat-generating component overlaps the region of the protrusions 35. Note that all or part of the terminals may overlap the region of the protrusion 35.

  The peripheral wall portion 33 is formed at a height higher than the position of the upper end of the circuit board 21 in a state where the spacer 40 and the circuit board 21 are stacked on the mounting portion 29. The peripheral wall portion 33 is divided according to the positions of the connector portions 17A and 17B and the connector terminal 24. On the outside of the peripheral wall portion 33, a boss portion 34 in which a screw hole is formed is formed so as to project outward.

(Spacer 40)
The spacer 40 is an insulative plate-like plate having a thickness (vertical dimension) that does not easily bend, and is rectangular as shown in FIG. A plurality (14 in this embodiment) of insertion holes 41, screw through holes 42A and 42B through which shafts of screws 48 (bolts) pass, terminal through holes 43, positioning projections 44A and 44B, A convex portion 45 is formed.

  The insertion holes 41 have a perfect circular shape and pass through the spacer 40. Depending on the position of the protrusion 35 of the heat dissipation member 28, the four or two insertion holes 41 are equally spaced (FIG. 8). Are arranged side by side in a plurality of rows, and in each row, a plurality of insertion holes 41 are arranged at equal intervals (intervals in the vertical direction in FIG. 8). The insertion hole 41 near the screw through hole 42B is spaced a predetermined distance from the screw through hole 42B so as not to receive a force when screwing into the screw through hole 42B. The row of the insertion holes 41 at a close position is arranged at a position shifted from the other rows. The diameter of each insertion hole 41 is increased in a tapered shape toward the lower side.

  The screw holes 42 </ b> A and 42 </ b> B are formed at positions near the peripheral edge of the spacer 40. The terminal through hole 43 penetrates the spacer 40 in a rectangular shape. The positioning convex portions 44 </ b> A and 44 </ b> B are cylindrical and protrude from coaxial positions on the upper surface and the lower surface of the spacer 40, respectively, and are arranged at positions near the corners of the peripheral edge portion of the spacer 40. The positioning protrusions 44A and 44B are fitted into the upper and lower positioning holes 23 and 31B, respectively, to position the spacer 40 with respect to the circuit board 21 and the heat dissipation member 28.

  The locking projection 45 protrudes upward in the vicinity of the position where the connector terminal 24 is disposed, and is inserted into a locking hole 24 </ b> A that penetrates the connector terminal 24 side of the circuit board 21. The engaging projection 45 receives a force at the time of mating with a mating connector (not shown), so that a force at the time of connector mating is hardly generated on the circuit board 21 side.

  A thick portion 40A having an increased thickness on the upper surface side is formed at the peripheral portion of the spacer 40, and a strip-shaped protrusion 46 stands up. The spacer 40 is made of an insulating plastic (synthetic resin) and is made of a material having such a strength that it is not easily deformed by the force of screwing.

(Heat transfer part 47)
The heat transfer section 47 is made of a member having adhesiveness such as an adhesive, adhesive sheet, adhesive tape or the like having high thermal conductivity. As the adhesive, for example, an adhesive that is solidified at room temperature by mixing two liquids such as an epoxy adhesive can be used. Adhesive sheets and adhesive tapes can be made by applying an adhesive to a base material. For example, an adhesive having an insulating property is applied to both surfaces of an insulating synthetic resin film. Can be used. Moreover, it is also possible to use the heat-transfer part 47 which does not have adhesive force or does not have high adhesive force, for example, may use a thermal radiation gel, thermal radiation grease, and a heat conductive sheet. As shown in FIG. 4, the heat transfer portion 47 is applied in a circular shape over the entire surface other than the edge portion of the upper surface of the protrusion 35. The thickness of the heat transfer part 47 is the thickness obtained by subtracting the height dimension of the protrusion 35 from the distance between the circuit board 21 and the flat part 30 of the heat dissipation member 28 (heat transfer between the circuit board 21 and the flat part 30). The dimension in which the portion 47 and the protrusion 35 are arranged in the vertical direction with almost no gap). Since the electronic component 26 is arranged so that a part or all of the electronic component 26 overlaps the heat transfer portion 47, the heat of the electronic component 26 is easily transferred to the heat transfer portion 47, and the heat transferred to the heat transfer portion 47 is dissipated. Heat is radiated from the member 28 to the outside.

Next, the manufacturing method of the circuit structure 20 and the electrical junction box 10 is demonstrated.
The protrusion 35 of the heat dissipation member 28 is fitted into the insertion hole 41 of the spacer 40, and the spacer 40 is placed at a predetermined position on the upper surface of the heat dissipation member 28 (FIG. 12).
Next, an adhesive is applied to the upper surface of the protrusion 35.
Further, the printed circuit board 21A and the bus bar board 21B are bonded to each other with an adhesive member to form the circuit board 21, a solder paste is attached to the conductive path of the circuit board 21, and reflow soldering through a reflow furnace is performed. 26 is mounted on the circuit board 21.
Next, the circuit board 21 is placed on the spacer 40 and the heat transfer section 47 (FIG. 13).

  Next, the circuit board 21 and the heat radiating member 28 are fixed with screws 48. Thereby, the circuit structure 20 is formed. The circuit structure 20 is covered with the shield cover 11 and screwed with screws 13 to form the electrical junction box 10.

According to this embodiment, the following operations and effects are achieved.
According to this embodiment, the heat of the circuit board 21 can be radiated by the heat radiating member 28 via the heat transfer section 47 and the protrusion 35. Here, since the heat transfer portion 47 has a thickness dimension that is reduced by the amount by which the protrusion 35 is inserted into the insertion hole 41, the heat transfer between the circuit board 21 and the protrusion 35. Conductivity can be increased, and heat dissipation can be improved. Moreover, since the dimension between the circuit board 21 and the heat radiating member 28 is maintained at the thickness dimension of the spacer 40, a jig for maintaining a constant distance between the circuit board 21 and the heat radiating member 28 is not used. Therefore, the manufacturing cost can be reduced.

Further, the heat transfer section 47 has an adhesive property for bonding between the circuit board 21 and the protrusion 35.
When the area to which the adhesive is applied is large, it takes time to apply the adhesive, and there is a problem that the adhesive starts to harden during the application of the adhesive and a portion where the adhesive is not sufficiently bonded occurs. According to this embodiment, since the heat transfer part 47 adheres the protrusions 35 with an adhesive, the adhesive is applied to the areas other than the areas of the protrusions 35 as compared with the case of bonding with an adhesive. Since the area can be reduced, the application time of the adhesive can be reduced. Therefore, it is possible to suppress a sticking failure between the circuit board 21 and the heat dissipation member 28 due to the adhesive being cured during application.

Moreover, what is hardened | cured at normal temperature is used for the heat-transfer part 47. FIG.
If a thermosetting adhesive that cures by heating is used, the adhesive can be prevented from curing during application of the adhesive, but the equipment cost for heating the adhesive increases and the adhesive dissipates heat. If the entire surface of the member 28 is applied, the amount of adhesive applied increases, which raises a problem that the material cost increases. According to the present embodiment, the material cost can be reduced by using, for the heat transfer section 47, an adhesive that cures at room temperature, which is cheaper than a thermosetting adhesive.

The circuit board 21 and the heat dissipation member 28 are screwed (bolted) with screws 48.
In this way, the screw 40 can firmly fix the space between the circuit board 21 and the heat dissipation member 28 while receiving the force at the time of screwing with the spacer 40.

Furthermore, the electronic component 26 is mounted at a position overlapping at least a part of the heat transfer section 47 on the circuit board 21.
In this way, the heat of the electronic component 26 can be radiated through the heat transfer portion 47 and the protrusion 35.

Further, the protrusion 35 is fitted into the insertion hole 41.
If it does in this way, positioning between the spacer 40 and the heat radiating member 28 can be performed about the direction orthogonal to the insertion direction of the protrusion 35 using the protrusion 35. FIG.

<Embodiment 2>
Next, Embodiment 2 will be described with reference to FIG.
In the first embodiment, the protrusion 35, the insertion hole 41, and the heat transfer portion 47 are circular, but in the circuit configuration body of the second embodiment, the protrusion 51, the insertion hole 53, and the heat transfer portion (not shown). Is a rectangular shape having a larger area than that of the first embodiment. Since other configurations are the same as those of the first embodiment, the same configurations as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

As shown in FIG. 14, a plurality of protrusions 51 that protrude upward in a rectangular shape (cuboid shape) are formed on the upper surface of the heat radiating member 50. The spacer 52 placed on the heat radiating member 50 has a plurality of insertion holes 53 into which the protrusions 52 are fitted.
The protrusion 51, the insertion hole 53, and the heat transfer part have a larger area and a smaller number than the protrusion 35, the insertion hole 41, and the heat transfer part 47 of the first embodiment. The protrusion 51, the insertion hole 53, and the heat transfer portion are formed so as to overlap the electronic component 26 that is a plurality of high heat generation components (a plurality of high heat generation components are arranged in the region of the heat transfer portion). Thereby, the heat of the electronic component 26 which is a some high heat-emitting component can be radiated | emitted from the heat radiating member 50 through the protrusion 51 and a heat-transfer part.

<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, position, number, etc. of the protrusions 35 are not limited to the above embodiment. For example, the shape of the protrusion 35 may be a shape other than a circle or a rectangle (for example, an ellipse or a polygon). Further, the intervals between the plurality of protrusions 35 may not be equal.

(2) The heat transfer section 47 is not limited to the adhesive of the above embodiment, and various adhesives can be used. For example, a thermosetting or thermoplastic adhesive can be used. The heat transfer part 47 and the protrusions 35 and 51 may overlap all the heat transfer parts 47 and all the protrusions 35 and 51 with the electronic component 26 which is a high heat generation part. The heat transfer section 47 and the protrusions 35 and 51 may be configured such that one heat transfer section 47 and the protrusions 35 and 51 overlap the electronic component 26 that is a high heat generation component.

(3) The heat dissipating member 28 is not limited to aluminum or aluminum alloy as long as it is a metal material having high thermal conductivity. For example, the heat dissipation member 28 may be made of copper or a copper alloy.

(4) The electronic component 26 is not limited to the above components, and can be various electronic components.
(5) In the said embodiment, although both adhesion | attachment by the heat-transfer part 47 and screwing were performed, you may perform any one of adhesion | attachment by the heat-transfer part 47, and screwing.

(6) The circuit board 21 and the heat radiating member 28 are fixed with screws 48, but the circuit board 21 and the heat radiating member 28 are fixed with fixing means other than screws (for example, a lock mechanism). May be.

21: Circuit board 22: Screw hole 26: Electronic component 28, 50: Heat radiation member 35, 51: Projection 31A: Screw hole 40, 52: Spacer 41, 53: Insertion hole 42A, 42B: Screw passage hole 47: Heat transfer Part 13, 48: Screw

Claims (7)

A circuit board having a conductive path on which electronic components are mounted;
A heat dissipating member that has a protrusion protruding on the side of the circuit board while being radiated from the heat of the circuit board that is overlaid on the circuit board.
A spacer formed between the circuit board and the heat dissipating member and having a through hole through which the protrusion is inserted;
A circuit configuration body comprising: a heat transfer section that is disposed between the circuit board and the protrusion in the insertion hole and transfers heat of the circuit board to the protrusion. The circuit structure according to claim 1, wherein the heat transfer section has an adhesive property for bonding between the circuit board and the protrusion. The circuit structure according to claim 1, wherein the heat transfer part is one that cures at room temperature. The circuit configuration body according to any one of claims 1 to 3, wherein the circuit board and the heat dissipation member are screwed together. 5. The circuit structure according to claim 1, wherein the electronic component is mounted at a position overlapping at least a part of the heat transfer section on the circuit board. The circuit structure according to claim 1, wherein the protrusion is fitted into the insertion hole. An electrical junction box comprising the circuit structure according to any one of claims 1 to 6.

Images