JP5326940B2 - Circuit structure and electrical junction box - Google Patents

Description

  The present invention relates to a circuit structure and an electrical junction box formed by superposing a circuit board and a power conduction plate.

  Conventionally, a circuit structure in which a circuit board on which an electronic component is mounted and a power conduction plate electrically connected to the electronic component on the circuit board is bonded is known. An adhesive or the like is used.

Japanese Patent No. 4002427

  By the way, when a circuit board and a power conduction plate are bonded together using a member such as an adhesive, not only a member such as an adhesive is required, but also a press machine or the like for pressing the circuit board and the power conduction plate. Equipment is required. Further, in the production line, an application process of an adhesive and the like, a press process using a press, and a drying process for drying and solidifying the adhesive are required, and these multiple processes take time. In addition, it has been difficult to assure quality, such as deformation of the substrate caused by the difference in linear expansion coefficient of the substrate / adhesive / power conducting plate when the environmental temperature changes due to the use of the adhesive.

  Therefore, a product that is resistant to changes in environmental temperature, a request to reduce costs by reducing the number of parts and materials required for bonding, a request to reduce production time by reducing the number of processes in the production line, and a cost reduction There was a demand for a structure.

  The present invention has been completed on the basis of the above circumstances, and is a circuit that suppresses production costs, adheres a circuit board and a power conduction plate without using an adhesive, and is resistant to changes in environmental temperature. An object is to provide a structure and an electrical junction box.

  The circuit structure according to the present invention has a conductive path, and is overlaid on a circuit board on which an electronic component connected to the conductive path is mounted, and a surface of the circuit board opposite to the electronic component mounting surface. The metal power conduction plate, the plurality of resin filling holes penetrating the circuit board and the power conduction plate, and the electronic component mounting surface of the circuit board, except for the edge of the resin filling hole A solder resist layer formed in a portion, and a plurality of resin connecting portions filled in each of the resin filling holes, wherein the resin connecting portion has a hole edge of the resin filling hole on the electronic component mounting surface A first locking portion that is locked to a portion, and a second locking portion that is locked to a hole edge portion of the resin filling hole on a surface of the power conducting plate opposite to the circuit board. (Means 1).

  According to the configuration of the means 1, the circuit board and the power conduction plate are locked by the first locking portion of the resin connecting portion on the circuit board side, and the second locking portion is locked on the power conduction plate side. Stopped. Thereby, a production cost can be suppressed and a circuit board and a power conduction board can be fixed without using an adhesive. In addition, by using a resin connection part for fixing the circuit board and the power conduction plate, the circuit board and the power conduction plate can be connected even when the environmental temperature changes compared to the case where the circuit board and the power conduction plate are fixed. Since play is likely to occur, deformation of the circuit board due to a difference in linear expansion coefficient between them can be suppressed. Therefore, it is possible to obtain a circuit structure that is resistant to changes in environmental temperature.

In the configuration of the means 1, the first locking portion is characterized in that it is formed without protruding from the surface of the solder resist layer (means 2).
According to the configuration of the means 2, since the convex portion is not formed on the surface of the circuit board, it is possible to perform solder printing by an existing printing machine, and it is easy to mount electronic components.

In the configuration of the means 2, the first locking portion is characterized in that it is formed flush with the surface of the solder resist layer (means 3).
According to the configuration of the means 3, since the surface of the circuit board can be flattened, the electronic component can be easily mounted. Moreover, since the thickness of the first locking portion can be ensured in a range that does not protrude from the surface of the solder resist layer, the locking force by the first locking portion can be increased while facilitating mounting of the electronic component. .

In the configuration according to any one of the means 1 to 3, in the plurality of resin connecting portions, the second locking portion in one resin connecting portion and the second locking portion in another resin connecting portion are integrated. The integrated second locking portion is formed with an extending portion extending to a portion including a terminal insertion hole through which the terminal is inserted, and the extending portion includes the terminal The terminal insertion hole is exposed at a position corresponding to the insertion hole, and a soldering hole that surrounds the terminal insertion hole is formed (means 4).
According to the configuration of the means 4, the circuit board and the power conduction plate can be securely fixed at the portion to which the terminal is connected. Moreover, since the manufacture of the metal mold | die for forming a 2nd latching | locking part becomes easy by uniting a some 2nd latching | locking part, manufacturing cost can be reduced.

The structure according to any one of means 1 to means 4 is characterized in that the resin connecting portion is formed in the vicinity of a terminal insertion hole through which a terminal is inserted (means 5).
According to the configuration of the means 5, the circuit board and the power conduction plate can be securely fixed in the vicinity of the connection portion of the terminal for which electrical connection is to be reliably maintained.

The structure according to any one of means 1 to means 5 is characterized in that the resin connecting portion is filled in a state in which a standing convex portion rising from the power conducting plate is inserted into the resin filling hole ( Means 6).
According to the structure of the means 6, since the contact area with the resin connecting portion is increased by the amount of the raised convex portion, the circuit board and the power conducting plate can be more firmly fixed.

In the configuration according to any one of the means 1 to 6, the through hole of the circuit board into which the rising convex part rising from the power conducting plate is inserted is disposed in the vicinity of the electronic component, and the rising is performed by soldering. A feature is that the convex portion and the terminal of the electronic component are electrically connected (means 7).
According to the configuration of the means 7, the electronic component is supplied with electric power through the rising convex portion of the power conduction plate located in the vicinity thereof, so that the loss caused by the wiring resistance of the circuit board is greatly reduced. The circuit board can be reduced in heat generation. Further, by reducing the wiring resistance of the circuit board and suppressing the heat generation of the circuit board, it is possible to alleviate the thermal stress on the solder part and the like, and the reliability to the environmental test can be improved.

  An electrical junction box according to the present invention is characterized by comprising the circuit structure according to any one of means 1 to means 7 and a case in which the circuit structure is accommodated (means 8).

  According to the present invention, it is possible to provide a circuit structure that is resistant to changes in environmental temperature by suppressing the production cost and fixing the circuit board and the power conduction plate without using an adhesive.

The perspective view showing the electric junction box concerning Embodiment 1 The perspective view showing the state which decomposed | disassembled the electrical junction box A perspective view showing a circuit board and a power conduction plate The perspective view showing the circuit structure in which the resin connection part was formed The perspective view which turned FIG. 4 upside down The expanded sectional view showing the state where the circuit board and the electric power conduction board were connected with the resin connection part An enlarged cross-sectional view showing a state in which a circuit board having a raised projection in the resin filling hole and a power conduction plate are connected by a resin connecting portion. The perspective view showing the state before a terminal module is attached to a circuit structure The perspective view showing the state where the terminal module was attached to the circuit structure

<Embodiment 1>
Embodiment 1 of the present invention will be described below with reference to FIGS.
The electrical junction box 10 in this embodiment is connected between a power source (not shown) such as a battery and on-vehicle electrical components (not shown) such as a headlamp and a wiper, and power to various on-vehicle electrical components. And supply power control. In the following description, it is assumed that the diagonal upper right in FIG. 1 is the front and the diagonal lower left is the rear.

  As shown in FIG. 2, the electrical junction box 10 includes a circuit structure 20 on which the electronic component 11 is mounted, a terminal module 60 composed of a large number of terminal groups and attached to the circuit structure 20, the circuit structure 20 and the terminals. It comprises a case main body 71 in which the module 60 is accommodated, and a case cover 72 that covers the front surface of the case main body 71.

  The circuit structure 20 includes a circuit board 22 on which the electronic component 11 is mounted and a metal power conduction plate 30 that is superimposed on the circuit board 22, and the circuit structure 20 (the circuit board 22 and the power conduction board 30). A large number of through holes 23 (through hole group) are formed.

  Specifically, as shown in FIG. 4, these through holes 23 electrically connect the terminal insertion holes 24 through which the terminals of the terminal module 60 are inserted, the conductive paths of the circuit board 22, and the power conduction plate 30. A relay hole 25 for connection, a positioning hole 26 for positioning in the case main body 71, and a resin filling hole 27 filled with a resin connecting portion 50 described later are provided.

The terminal insertion hole 24 is generally formed at a position near the front end of the circuit structure 20.
The relay hole 25 is formed corresponding to the position of an upright convex portion 36 (to be described later) of the power conduction plate 30, and by filling the relay hole 25 with solder in a state where the upright convex portion 36 is inserted, The conductive path of the circuit board 22 and the power conduction plate 30 are electrically connected.

  The positioning holes 26 are formed at the positions of the four corners of the circuit component 20, and positioning projections (not shown) formed at the positions of the four corners inside the case main body 71 of the electrical junction box 10 are fitted. The circuit component 20 is positioned inside the case 70.

The circuit board 22 has a rectangular shape, and a large number of conductive paths (not shown) are formed on one surface (upper surface) according to the control circuit, and the terminals of the electronic component 11 are connected to the conductive paths. .
As shown in FIG. 3, a large number of circular substrate through holes 24 </ b> A to 27 </ b> A that form the through holes 23 of the circuit structure 20 are formed in the circuit board 22.
Of the substrate through holes 24A to 27A, the substrate through holes 24A, 25A, and 27A constituting the terminal insertion hole 24, the relay hole 25, and the resin filling hole 27 are circular through holes having substantially the same size.

Four board through holes 26 </ b> A constituting the positioning holes 26 are formed at four corner positions of the circuit board 22.
The circuit board 22 can be separated from support portions (not shown) on both side ends by a separation groove 29.

A solder resist layer 45 is formed on the surface of the circuit board 22 (circuit component 20) (the surface on which the electronic component 11 is mounted).
The solder resist layer 45 is formed on the surface of the circuit board 22 except for the copper foil in the vicinity of the terminal of the electronic component 11 which is a portion that needs to be soldered and the hole edge portion 28A of the resin filling hole 27. .
The solder resist layer 45 refers to a synthetic resin film (an epoxy resin film having photosensitivity and insulation properties) formed on the circuit board 22 so that solder is not attached to a portion that does not require soldering. .

The power conducting plate 30 is made of two (a plurality of) substantially rectangular metal plate members, and is approximately the size of the circuit board 22 when the two plates are arranged side by side.
In the power conduction plate 30, conduction plate through-holes 37 to 39 constituting the through-hole 23 of the circuit component 20 are formed.
The conduction plate through-holes 37 to 40 are a small-diameter circular small-diameter through-hole 37 constituting the terminal insertion hole 24 and the resin filling hole 27, and a rectangular rectangular through-hole constituting the relay hole 25 and the resin filling hole 27. 38, a large-diameter through hole 39 that has a slightly larger diameter and surrounds a plurality of terminals, and a conduction plate through-hole 40 that constitutes the positioning hole 26.

The rectangular through hole 38 is formed with an upstanding convex portion 36 that rises upward from a hole edge on one end side (left side). The standing convex portion 36 is formed to rise upward (bend upward) from one side (left side) of the rectangle with a certain width dimension.
The upstanding convex portion 36 is inserted into the substrate through hole 25 </ b> A constituting the relay hole 25 of the circuit board 22 and the substrate through hole 27 </ b> A constituting the resin filling hole 27.
A pair of conductive plate through-holes 40 corresponding to the positioning holes 26 on the front side is formed, and portions corresponding to the positioning holes 26 on the rear side are formed by cutting out the corners of the power conductive plate 30. .

  In addition, the formation method of the standing convex part 36 can be formed by punching a metal plate material in a U-shape and bending the flat rectangular portion that becomes the standing convex part 36.

Here, as shown in FIG. 6, a resin connecting portion 50 for fixing the circuit board 22 and the power conduction plate 30 so as not to be separated is formed in the resin filling hole 27 of the circuit structure 20.
The resin connecting portion 50 includes a filling portion 51 in which the resin filling hole 27 is filled with a synthetic resin, a first locking portion 52 that locks on the surface of the circuit board 22 (the mounting surface of the electronic component 11), and power conduction. It has the 2nd latching | locking part 53 latched to the back side (surface on the opposite side to the circuit board 22) of the board 30. FIG.

  The filling portion 51 is formed by filling the resin filling hole 27 with a synthetic resin with almost no gap. In addition, as shown in FIG. 7, the filling portion 51 in which the rising convex portion 36 is inserted into the resin filling hole 27 fills the resin filling hole 27 with no gap in a state where the synthetic resin is in close contact with the rising convex portion 36. .

  The first locking portion 52 is a portion that is continuous with the filling portion 51 above the resin filling hole 27, and is a disk-like engagement generated by the hole edge portion 28 </ b> A of the resin filling hole 27 where the solder resist layer 45 is not formed. The entire stop recess 43 is filled. Therefore, the shape of the first locking portion 52 is the same disk shape as the locking recess 43 on the upper side of the resin filling hole 27, and the diameter thereof is larger than that of the resin filling hole 27 (that is, the resin on the mounting surface of the electronic component 11). The size including the hole edge portion 28A of the filling hole 27). Further, the thickness of the first locking portion 52 is substantially equal to the thickness of the solder resist layer 45, and can maintain a locking force (strength of the first locking portion 52) that does not separate the circuit board 22 from the power conducting plate 30. The upper surface is flush with the surface of the solder resist layer 45. Thereby, the first locking portion 52 having a diameter larger than that of the resin filling hole 27 is locked to the hole edge portion 28 </ b> A of the resin filling hole 27.

  The second locking portion 53 is a portion connected to the filling portion 51 below the resin filling hole 27, and the second locking portion 53 has a predetermined thickness (engagement on the back side of the power conduction plate 30. The thickness is such that the stopping force can be maintained.

As shown in FIG. 5, the second locking portion 53 is provided according to the shape of the conduction plate through holes 37 to 39, and the second locking portion 53 provided in the round small diameter through hole 37 is round. The second locking portion 53 provided in the rectangular through hole 38 has a rectangular shape.
The size of the second locking portion 53 is larger than the size (diameter) of each of the conduction plate through holes 37 to 39 (that is, the resin filling hole 27 on the surface on the back side of the power conduction plate 30). Of the hole edge portion 28B). Accordingly, the second locking portion 53 having a diameter larger than that of the resin filling hole 27 is locked to the hole edge portion 28 </ b> B of the resin filling hole 27.

  Moreover, the 2nd latching | locking part 53 of the vicinity of the terminal penetration hole 24 (near the part where the terminal penetration hole 24 was located in a line) among the 2nd latching | locking parts 53 is the 2nd latching | locking part 53 adjacent in the width direction. It has the extension part 54 extended to the position which continues.

The extending portion 54 in which the plurality of second locking portions 53 are integrated is extended to a position where at least one terminal insertion hole 24 is formed (a position where substantially the entire large-diameter through hole 39 is included). In addition, a soldering hole 55 that exposes the terminal insertion hole 24 and surrounds the terminal insertion hole 24 (large diameter through hole 39) is formed at the position of the terminal insertion hole 24 (large diameter through hole 39). .
The soldering hole 55 is formed in a tapered shape whose peripheral surface extends downward (back side). By this soldering hole 55, it is possible to prevent the solder from adhering to a portion other than the necessary portion.

  In the present embodiment, the resin connecting portion 50 is formed by mold molding in which a resin is injected into a mold by a resin molding machine (not shown). However, the present invention is not limited to this, and other molding methods may be used. For example, in a thermosetting resin, transfer molding, compression molding, or the like may be used, or a combination of molding methods such as insert molding may be used. In this embodiment, polyphenylene sulfide (PPS) resin is used as the resin to be injected. In addition, you may inject | pour another thermosetting resin, another thermoplastic resin, etc.

  As shown in FIG. 2, the case body 71 includes a rectangular and thin circuit housing portion 73 that accommodates the circuit component 20, and a connector in which a substantially front half of the circuit housing portion is thickened in a stepped shape. Part 74.

  The rear end portion of the connector portion 74 is provided with a plurality of connector fitting recesses 75 arranged side by side, and the terminals constituting the terminal module 60 protrude rearward from the back end portion of each connector fitting recess 75. Yes. A plurality of connectors (not shown) are fitted into the connector fitting recess 75.

Next, the manufacturing method of an electrical junction box and a circuit structure is demonstrated.
A conductive path made of copper foil is formed on the circuit board 22 by, for example, a known subtractive method.
Then, a solder resist is applied to a portion of the surface of the circuit board 22 excluding the hole portion 28 </ b> A of the resin filling hole 27 and a portion of the conductive path for soldering the terminal.
Next, the circuit board 22 and the power conduction plate 30 are set in a mold in a state of being overlapped. Of the molds, the upper mold has a flat portion corresponding to the locking recess 43 of the circuit board 22 and the lower mold is formed according to the shape of the second locking portion 53. A recess is formed.

Next, the PPS resin is injected into the mold by a resin molding machine. Then, after the PPS resin is cured, the integrated circuit board 22 and power conduction plate 30 are taken out of the mold.
Next, after supplying solder with a solder printing machine, the electronic component 11 is placed on the circuit board 22 and soldered to a predetermined conductive path, terminal, and the like, whereby the circuit structure 20 is manufactured. .
And each terminal of the terminal module 60 is inserted in the terminal insertion hole 24 of the circuit structure 20, and it solders to the soldering hole 55 (FIG. 9).
And after accommodating the circuit structure 20 in the case main body 71, the case cover 72 is covered and it becomes the electrical junction box 10. FIG.

According to this embodiment, the following effects can be obtained.
The circuit board 22 and the power conduction plate 30 constituting the circuit structure 20 are locked by the first locking part 52 of the resin connecting part 50 on the circuit board 22 side, and the second on the power conduction plate 30 side. It is locked by the locking portion 53. Thereby, the production cost can be suppressed, and the circuit board 22 and the power conduction plate 30 can be fixed without using an adhesive.
In addition, by using the resin connecting portion 50 for fixing the circuit board 22 and the power conduction plate 30, the power conduction to the circuit board 22 can be achieved even when the environmental temperature changes as compared with the case where the circuit board 22 and the power conduction plate 30 are fixed by an adhesive. Play is likely to occur between the plate 30. Accordingly, since the deformation of the circuit board 22 due to the difference in linear expansion coefficient can be suppressed, the circuit structure 20 that is resistant to changes in the environmental temperature can be obtained.
The first locking portion 52 is formed flush with the surface of the solder resist layer 45. Therefore, since the surface of the circuit board 22 can be flattened, the electronic component 11 can be easily mounted.

  Further, for the plurality of resin connecting portions 50, the second locking portion 53 in one resin connecting portion 50 and the second locking portion 53 in another resin connecting portion 50 are integrated, and this is integrated. The second locking portion 53 is formed with an extending portion 54 that extends to a portion including the plurality of terminal insertion holes 24 through which the terminals of the electronic component 11 are inserted, and the extension portion 54 has a terminal insertion hole. A soldering hole 55 that exposes the terminal insertion hole 24 and surrounds the terminal insertion hole 24 is formed at a position corresponding to 24. Therefore, the circuit board 22 and the power conduction plate 30 can be securely fixed to the portion where the terminal of the electronic component 11 is connected. In addition, by integrating the plurality of second locking portions 53, it becomes easy to manufacture a mold for forming the second locking portions 53, so that the manufacturing cost can be reduced.

  Moreover, since the resin connection part 50 is formed in the vicinity of the terminal insertion hole 24, the circuit board 22 and the power conduction plate 30 can be securely fixed in the vicinity of the connection part of the terminal for which electrical connection is desired to be maintained. .

  Further, the resin connecting portion 50 is filled in a state in which the standing convex portion 36 rising from the power conduction plate 30 is inserted into the resin filling hole 27. Therefore, since the contact area with the resin connecting portion 50 is increased by the amount of the raised convex portion 36, the circuit board 22 and the power conduction plate 30 can be more firmly fixed.

  In addition, since power is supplied to the electronic component 11 via the rising convex portion 36 rising from the power conducting plate 30 located in the immediate vicinity, the loss caused by the wiring resistance of the circuit board 22 is greatly reduced. The circuit board can be reduced in heat generation.

<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) Although the surface of the first locking portion 52 is flush with the upper surface of the solder resist layer 45, the present invention is not limited to this. The convex portions on the surface of the circuit board 22 may be eliminated by lowering the surface than the upper surface of the solder resist layer 45, and by making the height higher than the upper surface of the solder resist layer 45, You may make it raise intensity | strength.

DESCRIPTION OF SYMBOLS 10 ... Electrical junction box 20 ... Circuit structure 22 ... Circuit board 24 ... Terminal insertion hole 25 ... Relay hole 27 ... Resin filling hole 28A, 28B ... Hole edge 30 ... Power conduction board 36 ... Standing convex part 45 ... Solder resist layer DESCRIPTION OF SYMBOLS 50 ... Resin connection part 51 ... Filling part 52 ... 1st latching | locking part 53 ... 2nd latching | locking part 54 ... Extension part 55 ... Soldering hole 60 ... Terminal module

Claims (8)

A circuit board having a conductive path and mounted with electronic components connected to the conductive path;
A metal power conduction plate overlaid on the surface of the circuit board opposite to the electronic component mounting surface;
A plurality of resin filling holes penetrating the circuit board and the power conduction plate;
Of the electronic component mounting surface of the circuit board, a solder resist layer formed on a portion excluding a hole edge of the resin filling hole,
A plurality of resin coupling portions filled in each of the resin filling holes,
The resin connecting portion is
On the hole edge portion of the resin filling hole on the surface opposite to the circuit board of the power conduction plate, the first locking portion to be locked to the hole edge portion of the resin filling hole on the electronic component mounting surface. And a second locking portion for locking. The circuit structure according to claim 1, wherein the first locking portion is formed without protruding from the surface of the solder resist layer. The circuit structure according to claim 2, wherein the first locking portion is formed flush with a surface of the solder resist layer. For the plurality of resin connecting portions, the second locking portion in one resin connecting portion and the second locking portion in another resin connecting portion are integrated.
The integrated second locking portion is formed with an extending portion extending to a portion including a terminal insertion hole through which the terminal is inserted, and the extending portion corresponds to the terminal insertion hole. 4. The circuit structure according to claim 1, wherein the terminal insertion hole is exposed at a position, and a soldering hole is formed to surround the terminal insertion hole. 5. . 5. The circuit structure according to claim 1, wherein the resin connecting portion is formed in the vicinity of a terminal insertion hole through which a terminal is inserted. The said resin connection part is filled with the standing convex part rising from the said electric power conduction board inserted in the said resin filling hole, The Claim 1 thru | or 5 characterized by the above-mentioned. Circuit construct. A through hole of the circuit board through which the raised convex portion rising from the power conduction plate is inserted is disposed in the vicinity of the electronic component, and the raised convex portion and the terminal of the electronic component are electrically connected by soldering. The circuit structure according to any one of claims 1 to 6, wherein the circuit structure is provided. A circuit structure according to any one of claims 1 to 7,
An electrical junction box comprising: a case in which the circuit structure is accommodated.

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