JP5147482B2 - Electrical junction box - Google Patents

Description

  The present invention relates to an electrical junction box in which a substrate is accommodated in a case.

  Conventionally, the thing of patent document 1 is known as an electrical junction box. This electrical junction box is formed by housing a circuit board in a case. This circuit board is a so-called flexible board in which a conductive path is formed on a base film made of an insulating film such as polyimide.

The circuit board is accommodated in the case in a bent posture. Thereby, the wiring density in a case can be improved compared with the case where it accommodates in a case, without bending a circuit board.
JP 2004-40909 A

  However, according to said structure, since insulating films, such as a polyimide, are comparatively expensive, there exists a problem that product cost rises.

  Therefore, it is conceivable to use a circuit board in which a conductive path is formed on an insulating board made of a fiber base material and a synthetic resin and having bendability. Since the fiber base material and the synthetic resin are materials constituting a normal insulating substrate, it is expected that the increase in product cost can be suppressed.

  However, since the circuit board includes a fiber base material, there is a concern that when the circuit board is bent with a large curvature, the fiber included in the fiber base material is damaged, and thus a crack or the like is generated in the circuit board. Then, there is a concern that a short circuit or the like occurs due to the entry of foreign matter from the crack, resulting in a decrease in connection reliability.

  The present invention has been completed based on the above circumstances, and an object of the present invention is to provide an electrical junction box that reduces product cost and improves connection reliability.

The present invention is an electrical junction box comprising a case and a circuit board accommodated in the case, wherein the circuit board is made of a fiber base material and a synthetic resin and is electrically conductive with an insulating substrate having bendability. A path is formed, and an insulating plate having an outer dimension smaller than that of the circuit board is disposed in the case so as to overlap the circuit board, and the circuit board has at least one edge of the insulating plate. A bent portion is formed at a corresponding position, and the circuit board is accommodated in the case in a posture bent toward the insulating plate at the bent portion, and the bent portion of the edge of the insulating plate A curved surface is formed on a portion facing the curved surface to form a curved surface portion , the case is made of an insulating material, and the case is partitioned by a partition wall standing inward from the inner wall surface of the case. And bend at the bend Wherein the accommodating portion for accommodating the circuit board is formed.

  According to the present invention, since the insulating substrate constituting the circuit board is made of the fiber base material and the synthetic resin, the same material as that of a normal circuit board can be used. For this reason, compared with the case where a flexible printed circuit board is used, product cost can be reduced.

In addition, according to the present invention, the circuit board is gently bent along the curved surface formed in the curved surface portion provided at the edge of the insulating plate, so that the circuit board can be prevented from being bent with a large curvature. Thereby, since it can suppress that a crack generate | occur | produces in a circuit board, connection reliability can be improved.
Furthermore, according to said structure, the circuit board accommodated in the accommodating part is electrically insulated from the periphery by the partition wall.

As embodiments of the present invention, the following embodiments are preferable.
The curvature radius of the curved surface formed on the curved surface portion may be 0.5 mm or more.

  According to said structure, it can suppress that a circuit board is bent with a curvature radius smaller than 0.5 mm. Since the curvature increases as the radius of curvature decreases, according to the above configuration, the circuit board can be reliably prevented from being bent with a large curvature.

  The insulating plate overlaid on the circuit board has a holding pin protruding toward the circuit board, and the circuit board has a through hole at a position corresponding to the holding pin. The holding pin may be passed through the through hole.

  When the circuit board is bent, a positioning jig or the like is required in order to bend it at an accurate position.

  According to said structure, a positioning between a circuit board and an insulating board can be performed by letting a holding pin penetrate the through-hole. The circuit board can be easily bent at an accurate position by bending the circuit board along the curved surface portion of the insulating substrate in a state where the circuit board and the insulating plate are positioned. As a result, a jig or the like is not required when performing the operation of bending the circuit board.

  The fiber base material may be a glass cloth.

  The synthetic resin may be a thermosetting resin. The thermosetting resin may be an epoxy resin.

  According to said structure, since a circuit board can be manufactured using the material of a general printed wiring board, product cost can be reduced.

  According to the present invention, the product cost of the electrical junction box can be reduced and the connection reliability can be improved.

  An embodiment in which the present invention is applied to an on-vehicle electrical junction box 10 will be described with reference to FIGS. The electrical connection box 10 of the present embodiment is arranged between a battery (not shown) and an on-vehicle electrical component (not shown) such as a lamp and a wiper, and the electric power supplied from the battery is supplied to the on-vehicle electrical component. Distribute. The electrical junction box 10 is configured by housing a circuit board 12 in a case 11. In the following description, the upper side in FIG. 1 is the upper side, and the lower side is the lower side. Further, the left side in FIG. 1 is the front and the right side is the rear. Further, the left side in FIG. 2 is the left side, and the right side is the right side.

(Lower case 13)
The case 11 has a lower case 13 (corresponding to a case) made of an insulating synthetic resin that opens upward, and an upper case 14 (corresponding to the case) made of an insulating synthetic resin that closes the opening of the lower case 13 from above. Consists of. A receiving portion 15 for receiving the lower edge of the side wall of the upper case 14 from below is formed on the upper edge of the side wall of the lower case 13 so as to be recessed from the outer surface of the side wall in the thickness direction of the side wall.

(Upper case 14)
A plurality of connector portions 16 into which mating connectors (not shown) can be fitted are formed in the upper wall of the upper case 14 so as to be depressed downward. The lower wall of the connector part 16 is opened, and the inside and outside of the case 11 communicate with each other through this opening.

  The lower case 13 and the upper case 14 are integrally assembled by known lock structures (not shown) provided in the lower case 13 and the upper case 14 respectively.

(Circuit board 12)
A circuit board 12 is accommodated in the lower case 13. As shown in FIG. 3, the circuit board 12 is formed by attaching a metal foil 18 to an insulating substrate 17 made of a fiber base material and a synthetic resin, and forming a conductive path by a printed wiring technique. The circuit board 12 may be formed with a single-layer conductive path, or may be formed with a plurality of layers of conductive paths.

  The thickness of the fiber base material is preferably 30 μm or less from the viewpoint of ensuring bendability. As the fiber base material, a woven fabric, a nonwoven fabric, or the like can be used. As the material of the fiber base material, inorganic fibers such as glass, alumina, boron, silica alumina glass, silica glass, silicon carbide, silicon nitride, zirconia, aramid, polyether ether ketone, polyether imide, polyether sulfone, Organic fibers such as carbon and cellulose, and mixed papers thereof can be used. Among these, from the viewpoint of obtaining excellent dimensional stability, heat resistance, and bendability, a woven fabric of glass fiber, that is, a glass cloth is preferable. In this embodiment, a glass cloth is used.

  The tensile elastic modulus of the synthetic resin is preferably 0.5 GPa to 10 GPa, more preferably 0.5 GPa to 8 GPa, and even more preferably 1 GPa to 5 GPa. If the tensile modulus exceeds 10 GPa, the bendability is lowered, which is not preferable. On the other hand, when the tensile elastic modulus at 20 ° C. to 30 ° C. is less than 0.5 GPa, the insulating substrate 17 is easily deformed and the strength is lowered, which is not preferable. The tensile elastic modulus can be obtained from, for example, an initial inclination of the measurement by measuring the stress-strain curve of the test substrate of the insulating substrate 17 with a tensile tester under the condition of a pulling speed of 5 mm / min (25 ° C.).

  As the synthetic resin, a thermosetting resin is preferable because it is excellent in moldability, heat resistance, and insulation. As the thermosetting resin, epoxy resin, polyimide resin, unsaturated polyester resin, polyurethane resin, bismaleimide resin, phenol resin, or the like can be used. Of thermosetting resins, epoxy resins are preferred because of their excellent heat resistance, mechanical properties, and electrical properties. In this embodiment, an epoxy resin is used.

  As metal foil, copper foil or aluminum foil can be used. Of these, copper foil is preferred because it is a common conductor material for printed wiring boards. In the present embodiment, copper foil is used.

  As shown in FIG. 4, the circuit board 12 is an electronic circuit formed by mounting a power circuit unit 19 in which a power circuit for distributing power supplied from a battery to in-vehicle electrical components is formed, and an electronic component (not shown). And an electronic circuit unit 20 formed with

(Power circuit unit 19)
The power circuit unit 19 includes a main body portion 21 having a substantially rectangular shape, and a pair of projecting portions 22 having a substantially rectangular shape, which are formed to project from the left and right sides of the main body portion 21 in FIG. The dimensions of the main body 21 are set to be substantially the same as or slightly smaller than the bottom wall of the lower case 13. Thereby, the main body 21 can be accommodated in the lower case 13 in a posture substantially parallel to the bottom wall of the lower case 13. Further, the projecting dimension of the projecting part 22 from the main body part 21 (the width dimension in the left-right direction in FIG. 4) is set to be substantially the same as or slightly smaller than the height dimension of the upper case 14.

  As shown in FIG. 2, the overhanging portion 22 is accommodated in the case 11 in a state of being bent upward in FIG. 2 at an angle substantially orthogonal to the plate surface of the main body portion 21. A first insulating plate 23 (corresponding to an insulating plate) made of an insulating synthetic resin is disposed on the upper surface of the main body 21 so as to overlap the upper surface of the main body 21. The outer dimension of the first insulating plate 23 is set to be substantially the same as the outer dimension of the main body 21. For this reason, the outer dimension of the first insulating plate 23 is set smaller than that of the circuit board 12.

  As shown in FIG. 2, in the power circuit portion 19, first bent portions 24 (corresponding to bent portions) are formed at positions facing left and right end edges (left and right end edges in FIG. 2) of the first insulating plate 23. Has been. In the first bending portion 24, a pair of protruding portions 22 that are formed to protrude to the left and right are bent in the direction toward the first insulating substrate 17 (upward in FIG. 2).

  As shown in FIG. 2, the upper end of the overhanging portion 22 bent upward is accommodated in an accommodating portion 26 partitioned by a partition wall 25 formed by hanging downward from the inner surface of the upper wall of the upper case 14. Has been.

  As shown in FIG. 5, a curved surface is formed on an edge of the first insulating plate 23 that faces the first bent portion 24, and a first curved surface portion 27 (corresponding to a curved surface portion) is formed. The power circuit unit 19 is bent along the curved surface formed in the first curved surface portion 27. The curvature radius of the curved surface formed in the first curved surface portion 27 is set to 0.5 mm or more.

  An insertion hole 28 is formed in the main body 21. A metal pin 29 is inserted into the insertion hole 28 and is connected to the conductive path on which the circuit board 12 is formed by soldering. The pin 29 is penetrated and held by a base 30 made of synthetic resin. The pedestal 30 is exposed in the connector portion 16 from the opening of the connector portion 16 formed in the upper case 14. Thus, the pin 29 is disposed in the connector portion 16 and can be connected to the mating connector.

  On the upper surface of the first insulating plate 23 in FIG. 1, a bus bar 31 formed by pressing a metal plate material is disposed along the plate surface of the first insulating plate 23. An end portion of the bus bar 31 is bent upward in FIG. 1 and is arranged in a connector portion 16 formed in the upper case 14. Thereby, the bus bar 31 and the counterpart connector can be connected.

(Electronic circuit unit 20)
As shown in FIG. 4, the electronic circuit portion 20 is formed so as to protrude downward from the main body portion 21 of the power circuit portion 19 in FIG. 4.

  As shown in FIG. 1, the electronic circuit unit 20 is accommodated in the case 11 in a state bent at an angle of about 180 degrees with respect to the plate surface of the main body unit 21. A second insulating plate 32 (corresponding to an insulating plate) made of an insulating synthetic resin is disposed on the lower surface of the main body 21 in FIG. As shown in FIG. 1, the outer dimension of the second insulating plate 32 is set larger than the electronic circuit unit 20 and smaller than the main body unit 21. As described above, the outer dimension of the second insulating plate 32 is set smaller than that of the circuit board 12.

  As shown in FIG. 1, in the region between the power circuit unit 19 and the electronic circuit unit 20 in the circuit board 12, at a position facing the front edge (the left edge in FIG. 2) of the second insulating plate 32, A second bent portion 33 (corresponding to a bent portion) is formed. In the second bent portion 33, the electronic circuit portion 20 is bent toward the second insulating plate 32 and bent at an angle of approximately 180 degrees with respect to the plate surface of the main body portion 21 of the power circuit portion 19.

  As shown in FIG. 6, a curved surface is formed on an edge of the second insulating plate 32 that faces the second bent portion 33 to form a second curved surface portion 34 (corresponding to a curved surface portion). The power circuit unit 19 is bent along a curved surface formed in the second curved surface portion 34. The curvature radius of the curved surface formed on the second curved surface portion 34 is set to 0.5 mm or more.

  As shown in FIGS. 6 and 7, the second insulating plate 32 is formed with a plurality (four in this embodiment) of positioning pins 35 projecting toward the electronic circuit unit 20 (downward in FIG. 6). Yes. The cross-sectional shape of the positioning pin 35 is circular.

  A plurality (four in the present embodiment) of through holes 36 are formed in the electronic circuit portion 20 of the circuit board 12 at positions corresponding to the positioning pins 35 formed on the second insulating plate 32. As shown in FIG. 7, the positioning pins 35 and the through holes 36 are formed in the vicinity of the four corners of the electronic circuit unit 20. The cross-sectional shape of the through hole 36 has a circular shape following the shape of the positioning pin 35. As shown in FIG. 6, a positioning pin 35 is passed through each through hole 36.

  Then, an example of the manufacturing process of the electrical junction box 10 which concerns on this embodiment is demonstrated. First, as shown in FIG. 4, the circuit board 12 is cut. In the circuit board 12, an insertion hole 28 and a through hole 36 are formed in advance in the same process. After the circuit board 12 is cut, an electronic component, a pedestal 30 through which the pins 29 are passed, and the like are soldered to the circuit board 12.

  Subsequently, the second insulating plate 32 is disposed so as to overlap the electronic circuit unit 20 of the circuit board 12. At this time, the positioning pins 35 formed on the second insulating plate 32 are passed through the through holes 36 formed in the electronic circuit unit 20. Thereafter, in the second bending portion 33 of the circuit board 12, the power circuit portion 19 is bent toward the second insulating plate 32 at an angle of about 180 degrees. At this time, the second bent portion 33 is bent along the second curved surface portion 34 of the second insulating plate 32.

  On the other hand, the bus bar 31 is formed by press-molding a metal plate material, and the bus bar 31 is disposed along the plate surface of the first insulating plate 23.

  Subsequently, the first insulating plate 23 is disposed so as to overlap the main body portion 21 of the circuit board 12. Thereafter, the protruding portion 22 of the circuit board 12 is bent at an angle of approximately 90 degrees toward the first insulating plate 23 side. At this time, the first bent portion 24 is bent along the first curved surface portion 27 of the first insulating plate 23.

  Thereafter, the circuit board 12 is accommodated in the lower case 13. At this time, the electronic circuit unit 20 is accommodated in a posture positioned on the bottom surface side of the lower case 13. Thereafter, the upper case 14 is assembled from above the lower case 13. At this time, the overhanging portion 22 is accommodated in the accommodating portion 26 of the upper case 14, and the pin 29 and the bus bar 31 are positioned in the connector portion 16 of the upper case 14. Thus, the electrical junction box 10 is completed.

  Then, the effect | action and effect of this embodiment are demonstrated. According to the present embodiment, the circuit board 12 has a pair of overhang portions 22. The overhang portion 22 is bent substantially orthogonally to the plate surface of the main body portion 21 of the circuit board 12 and is accommodated in the accommodating portion 26 of the upper case 14. Thereby, the wiring density can be improved without increasing the size of the electrical junction box 10. Furthermore, in the present embodiment, the circuit board 12 also has an electronic circuit unit 20. The electronic circuit portion 20 is bent at an angle of about 180 degrees with respect to the plate surface of the main body portion 21 and is accommodated in the case 11. Thereby, the wiring density of the electrical junction box 10 can be further improved.

  Further, since the main body portion 21 and the overhang portion 22 of the circuit board 12 are bent at the first bending portion 24, the conductive path formed in the main body portion 21 and the conductive path formed in the overhang portion 22 are different from each other. It is continuous. Thereby, for example, compared with the case where the conductive path formed in the main body part 21, the conductive path formed in the overhang part 22, and the separate circuit board 12 are formed, and the circuit boards 12 are connected to each other by a connector. Thus, the connector can be omitted. This eliminates the need for connector parts. In addition, connector mounting man-hours and soldering man-hours are not required. Furthermore, connection reliability can be improved compared to connection using a connector. Moreover, since the main-body part 21 and the electronic circuit part 20 are bending-processed, there can exist an effect similar to the above.

  Moreover, according to this embodiment, since the insulating substrate 17 which comprises the circuit board 12 consists of glass cloth and an epoxy resin, the same material as a normal circuit board can be used. For this reason, product cost can be reduced compared with the case where the flexible printed circuit board which forms a conductive path in a polyimide film is used.

  Further, according to the present embodiment, the circuit board 12 is bent at the first bent portion 24 and the second bent portion 33. Since this circuit board 12 has a conductive path formed on an insulating substrate 17 made of a fiber base material and a synthetic resin, if bending is performed with a large curvature, the fiber contained in the fiber base material is damaged, and the circuit board There is a concern that cracks will occur in the twelve.

  In view of the above points, in the present embodiment, the circuit board 12 is gently bent along the curved surface of the first curved surface portion 27 formed on the first insulating plate 23 in the first bending portion 24. Thereby, since it can suppress that a crack generate | occur | produces in the circuit board 12, connection reliability can be improved.

  Similarly to the above, the circuit board 12 is gently bent at the second bending portion 33 along the curved surface of the second curved surface portion 34 formed on the second insulating plate 32. Thereby, since it can suppress that a crack generate | occur | produces in the circuit board 12, connection reliability can be improved.

  Furthermore, according to this embodiment, the curvature radius of the curved surface formed in both curved surface parts is set to 0.5 mm or more. Thereby, it can suppress that the circuit board 12 is bent by the curvature radius smaller than 0.5 mm. Since the curvature increases as the radius of curvature decreases, according to the above configuration, the circuit board 12 can be reliably prevented from being bent with a large curvature.

  Further, when the circuit board 12 is bent, a positioning jig or the like is required in order to bend it at an accurate position. According to the present embodiment, positioning between the circuit board 12 and the second insulating plate 32 can be performed by passing the holding pin 29 through the through hole 36. By bending the circuit board 12 along the second curved surface portion 34 of the second insulating substrate 17 in a state where the circuit board 12 and the second insulating plate 32 are positioned, the circuit board 12 is easily bent at an accurate position. be able to. As a result, a jig or the like is not necessary when the operation of bending the circuit board 12 is performed.

Further, projecting portions 22 described above are housed in the housing portion 26 on the inner towards partitioned in partition wall 25 which is erected from the inner wall surface of the case 11. Thus, volume unit circuit board 12 accommodated in 26 yield, electrically insulated from the surrounding by the partition walls 25. Moreover, it can suppress that the overhang | projection part 22 rattles in the case 11. FIG.

<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) In the present embodiment, four positioning pins 35 are formed on the second insulating plate 32. However, the present invention is not limited to this, and one to three positioning pins 35 are formed. It is good also as composition to be.
On the other hand, when the circuit board 12 is bent using a jig or the like, the positioning pins 35 can be omitted.
(2) In the present embodiment, the positioning pin 35 formed on the second insulating plate 32 is formed so as to protrude to the electronic circuit unit 20 side. However, the present invention is not limited to this, and the positioning pin 35 includes the main body. It is good also as a structure which protrudes and forms the part 21 side, and the through-hole 36 is formed in the main-body part 21 side.
(3) In this embodiment, the cross-sectional shape of the positioning pin 35 is circular, but the cross-sectional shape of the positioning pin 35 is not limited to this, and the cross-sectional shape of the positioning pin 35 is oval or elliptical, triangular, square, etc. Any shape such as a polygonal shape may be used as necessary.
(4) In the present embodiment, the electronic circuit unit 20 is formed on the circuit board 12, but the electronic circuit unit 20 can be omitted if necessary.
(5) In the present embodiment, the upper case 14 is formed with the accommodating portion 26 for accommodating the overhanging portion 22. However, as a reference example , for example, the case 11 can be engaged with the overhanging portion 22. In the case where an engaging portion (for example, a hook that engages with the edge of the overhanging portion 22) is provided, the accommodating portion 26 can be omitted.
(6) In the present embodiment, the power circuit unit 19 has a configuration having a pair of overhanging portions 22, but is not limited thereto, and may have a configuration having one or three or more overhanging portions 22.
(7) In the present embodiment, the case 11 has a configuration in which one circuit board 12 is accommodated. However, the present invention is not limited thereto, and the case 11 may have a configuration in which a plurality of circuit boards 12 are accommodated.
(8) In the present embodiment, the main body portion 21 of the power circuit portion 19 is configured to have a substantially rectangular shape, but is not limited thereto, and may take any shape according to the shape of the case 11.
(9) The angle formed between the main body 21 and the overhanging portion 22 and the angle formed between the main body 21 and the electronic circuit portion 20 may be any angle greater than 0 degrees and 180 degrees or less, if necessary. Possible.

1 is a side sectional view of an electrical junction box according to an embodiment of the present invention. Front section of electrical junction box Cross-sectional schematic diagram showing a circuit board Plan view showing circuit board The principal part expanded sectional view which shows the 1st bending part of a circuit board, and the 1st curved surface part of a 1st insulating board. The principal part expanded sectional view which shows a circuit board and a 2nd insulating board The main part enlarged bottom view which shows a circuit board and a 2nd insulating board

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Electrical junction box 11 ... Case 12 ... Circuit board 13 ... Lower case (case 11)
14 ... Upper case (Case 11)
17 ... Insulating substrate 23 ... First insulating plate (insulating plate)
24 ... 1st bending part (bending part)
26: accommodating portion 27 ... first curved surface portion (curved surface portion)
32 ... Second insulating plate (insulating plate)
33 ... 2nd bending part (bending part)
34 ... 2nd curved surface part (curved surface part)
35 ... Locating pin 36 ... Through hole

Claims (6)

An electrical junction box comprising a case and a circuit board accommodated in the case,
The circuit board is made of a fiber base material and a synthetic resin, and a conductive path is formed on an insulating board having bendability, and an insulating plate having a smaller outer dimension than the circuit board is formed in the circuit board in the case. The circuit board is provided with a bent portion at a position corresponding to at least one edge of the insulating plate, and the circuit board is bent toward the insulating plate at the bent portion. It is accommodated in the case in a posture, and a curved surface is formed on a portion of the edge of the insulating plate facing the bent portion to form a curved surface portion, and the case is made of an insulating material, and the case Is formed by a partition wall standing inward from an inner wall surface of the case, thereby forming an accommodating portion for accommodating the circuit board bent by the bent portion. Connection box. The electrical junction box according to claim 1, wherein a radius of curvature of the curved surface formed in the curved surface portion is 0.5 mm or more. The insulating plate overlaid on the circuit board has a holding pin protruding toward the circuit board, and the circuit board has a through hole at a position corresponding to the holding pin. The electrical connection box according to claim 1, wherein the holding pin is penetrated in the through hole . The electrical connection box according to any one of claims 1 to 3, wherein the fiber base material is a glass cloth . The electrical junction box according to any one of claims 1 to 4, wherein the synthetic resin is a thermosetting resin . The electrical junction box according to claim 5 , wherein the thermosetting resin is an epoxy resin .

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