Circuit unit, electrical distribution box and manufacturing method for a circuit unit

Abstract

Circuit unit (20), comprising: a circuit section (21) having a terminal section (26A, 26B) connectable to an external terminal and a main section (28) on which an electronic component (22) is mounted, wherein a section of the circuit section (21) between the main section (28) and the terminal section (26A, 26B) is a section to be sealed (34) made of a plate-shaped metal; a first sealing portion (40) which is in close contact with the portion (34) to be sealed of the circuit portion (21) and is made of a plastic containing an adhesive component; and a second sealing portion (50) made of a plastic and in close contact with the circuit portion (21) and an outer surface of the first sealing portion (40), wherein the section to be sealed (34) has a recessed section (33) which allows penetration of the first sealing section (40), an outwardly projecting portion (43) is formed on an outer surface of a portion of the first sealing portion (40) which overlaps the recessed portion (33), and the recessed portion (33) is a through hole penetrating the portion (34) to be sealed.

Description

TECHNICAL FIELD

[0001] The present patent discloses a technique for preventing water from entering a circuit. TECHNICAL BACKGROUND

[0002] Techniques for sealing the interior of a unit housing a circuit are known. According to the technique described in JP 2004-31416A, a power circuit portion disposed on a heat dissipating member with an insulating layer therebetween is covered with a waterproof casing. The waterproof casing is provided with a hood for each external connection connector. A sealing portion filled with an epoxy resin is formed around the external connection terminal within the hood. The sealing portion prevents water from penetrating the waterproof casing along the external connection terminal.

[0003] DE 101 27 488 A1 discloses a connector comprising a plastic connector housing with connector pins that penetrate the connector housing in a sealing manner. The connector pins are formed as flat stamped parts. To seal against the connector housing, a seal is applied to each of the connector pins by overmolding the connector pins around a sealing area.

[0004] JP 2003 - 284 218 A discloses a connector structure which improves waterproof performance when water penetrates into the connector part and prevents water from penetrating through the punching hole of the molding press, and an efficient manufacturing method for the above structure using the punching hole of the molding press.The structure includes a resin-molded housing, a waterproof space forming part, a connector part, an internal circuit provided in a waterproof space, and a busbar molded into the housing, the housing being provided with a through-hole through the housing, the through-hole being a busbar. The housing has a through-hole through the housing, the through-hole being a busbar formed in the center of the busbar to be open all around and filled with a waterproof adhesive such that the waterproof adhesive is densely applied around the entire circumference of the open part of the busbar. The manufacturing method is such that the shape of the molding press during the molding process is such that the hole through which it is taken out is a through-hole open over the entire circumference of the busbar center part.

[0005] DE 100 41 812 A1 discloses a structural unit comprising a wall element, at least one conduit penetrating the wall element, and a sealing element arranged between the conduit and the wall element. The sealing element is made of a soft plastic material and the wall element is made of a hard plastic material. The structural unit is characterized in that the sealing element is applied, preferably injection-molded, to the conduit, and in that the wall element is applied, preferably injection-molded, to the sealing element, completely surrounds it, and exerts pressure on the sealing element to support the desired sealing function.

[0006] JP 2000-83312 A discloses an electrical junction box capable of smoothly performing connection work with an external circuit. The electrical junction box has a bottom wall, side walls enclosing the outer periphery thereof, and a terminal mounting portion provided on the side walls. Inside, there are three busbars stacked one on top of the other and insulated from each other by an insulating plate. Each busbar is provided with a cranked terminal block arranged in three stages, with its tip side projecting into the opening of the connector mounting portion. The connector mounting portion is formed integrally with the bottom wall and side walls to conform to the shape of the connector to be mounted in the connector mounting portion. The tip side of the projecting terminal block is also arranged to conform to the shape of the connector. OVERVIEW OF THE INVENTION

[0007] Although the above-described embodiment of JP 2004-31416A provides a sealing portion around the external connection terminal within the hood portion, a portion around a bus bar formed continuously with the external connection terminal within the waterproof casing is not covered by the waterproof structure. Accordingly, there is a concern that water may penetrate into the interior of the waterproof casing at the interface between the external connection terminal and the sealing portion.

[0008] The present invention has been developed in view of the above-described circumstances and has as its object to prevent the intrusion of water from the terminal portion side to the electronic component side.

[0009] A proposed circuit unit comprises the features of claim 1.

[0010] A proposed manufacturing method for a circuit unit comprises the features of claim 8.

[0011] According to the presently disclosed technique, it is possible to prevent the intrusion of water from the terminal portion side to the electronic component side. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a plan view showing an electrical distribution box according to an embodiment. Fig. 2 is a cross-sectional view along line AA of Fig. 1. Fig. 3 is a plan view showing a bus bar. Fig. 4 is a rear view showing the busbar. Fig. Figure 5 is a right side view showing the busbar. Fig. 6 is a perspective view showing a first molded product in which a first sealing portion is formed on the bus bar. Fig. 7 is a plan view showing the first molded product in which the first sealing portion is formed on the bus bar. Fig. 8 is an enlarged rear view showing a part of the first molded product in which the first sealing portion is formed on the bus bar. Fig. 9 is a cross-sectional view along line BB of Fig. 8. Fig. 10 is a right side view showing the first molded product in which the first sealing portion is formed on the bus bar. Fig. 11 is a perspective view showing a second cast product. Fig. 12 is a bottom view showing the second cast product. EMBODIMENTS OF THE INVENTION

[0012] First, embodiments of the present disclosure are cited and described.

[0013] (1) A circuit unit of the present disclosure comprises: a circuit portion having a terminal portion connectable to an external terminal and a main portion on which an electronic component is mounted, wherein a portion of the circuit portion between the main portion and the terminal portion is a portion to be sealed made of a plate-shaped metal; a first sealing portion in close contact with the portion to be sealed of the circuit portion and made of a resin containing an adhesive component;and a second sealing portion made of a plastic and in close contact with the circuit portion and an outer surface of the first sealing portion, wherein the portion to be sealed includes a depressed portion allowing penetration of the first sealing portion, and an outwardly projecting portion is formed on an outer surface of a portion of the first sealing portion that overlaps (or covers or is located in the region of) the depressed portion;

[0014] According to the above configuration, since the resin of the second sealing portion and the first sealing portion made of resin containing an adhesive component seal against the water flowing along the terminal portion, the water can be prevented from penetrating from the terminal portion side to the main portion side. Furthermore, since the position of the first sealing portion relative to the portion to be sealed is easily maintained by the penetration of the first sealing portion into the recessed portion, positional displacement of the first sealing portion can be prevented.Note that when the second sealing portion is formed by the second molding after the first sealing portion is formed, it is assumed that a portion of the first sealing portion is melted by the heat of the molten resin during the second molding, and a force is applied to the first sealing portion by the pressure of the molten resin. Here, the configuration in which the recessed portion is formed in the portion to be sealed has the advantage that the position of the first sealing portion can be maintained by the recessed portion.However, the melted first sealing portion easily migrates into the recessed portion or the like, and there is a concern that the thickness of the first sealing portion covering the portion to be sealed is reduced due to the migration of the first sealing portion, or that a portion not covered by the first sealing portion is generated in the portion to be sealed and the sealing performance is deteriorated.On the other hand, according to the above configuration, since the thickness of the portion overlapping the recessed portion of the portion to be sealed is increased due to the protruding portion of the first sealing portion, even if the first sealing portion melts in the recessed portion and migrates due to heat or pressure in the second molding, a sealing thickness of the first sealing portion covering the portion to be sealed can be easily ensured, and the deterioration of the sealing ability of the portion to be sealed by the first sealing portion can be prevented.

[0015] (2) The width of the protruding portion may be larger than an area of ​​the recessed portion that overlaps the protruding portion. With this configuration, even if the first sealing portion melts and migrates, a reduction in the sealing performance due to the size of the protruding area of ​​the protruding portion can be prevented.

[0016] (3) The recessed portion and the projecting portion may be provided on both sides of a plate surface of the portion to be sealed. With this design, the reduction of the sealing capacity on both sides of the plate surface of the section to be sealed can be prevented.

[0017] (4) The recessed portion may be a through hole penetrating the portion to be sealed. With this configuration, displacement of the first sealing portion due to heat and pressure during the secondary molding can be further prevented. Furthermore, the thickness of the first sealing portion can be increased in the region of the through-hole.

[0018] (5) The terminal portion may have a width dimension larger than that of a portion of the circuit portion with which the first sealing portion is in close contact. According to this configuration, in a configuration where it is not easy to attach a gasket made of rubber or the like due to the size of the width dimension of the terminal portion, sealing can be achieved without using the gasket.

[0019] (6) A portion between the terminal portion and the main portion in the circuit portion may be bent into a hook shape. According to this configuration, in a configuration where there is concern about the adhesion of the portion to be sealed during plastic molding due to the crank shape of the circuit portion, the intrusion of water from the outside can be prevented.

[0020] (7) The circuit portion may comprise a plate-shaped metal bus bar, the terminal portion and the portion to be sealed may be formed on the bus bar, and the first sealing portion and the second sealing portion may be in close contact with the bus bar. This design can prevent water from penetrating the busbar, through which a comparatively large current flows.

[0021] (8) An electrical junction box comprises the circuit unit, a heat dissipation member placed on the circuit unit, and a sealing member sandwiched between the circuit unit and the heat dissipation member.

[0022] (9) A manufacturing method for a circuit unit of the present disclosure includes: a first sealing step of bringing a first sealing portion made of plastic containing an adhesive component into close contact with a plate-shaped metal sealing portion provided in a circuit portion between a terminal portion connectable to an external terminal and an electronic component, the circuit portion including the terminal portion and a main portion on which the electronic component is mounted;and a second sealing step of forming a second sealing portion by bringing resin into close contact with the circuit portion and the first sealing portion, wherein in the first sealing step, the resin containing the adhesive component penetrates into a recessed portion formed in the portion to be sealed, and an outwardly projecting portion is formed on the outer surface of the first sealing step in the region of the recessed portion.;

[0023] According to the above configuration, since the resin of the second sealing portion and the first sealing portion made of resin containing an adhesive component seal against the water flowing along the terminal portion, the water can be prevented from penetrating from the terminal portion side to the main portion side. Furthermore, since the position of the first sealing portion relative to the portion to be sealed is easily maintained by the penetration of the first sealing portion into the recessed portion, positional displacement of the first sealing portion can be prevented.Note that when the second sealing portion is formed by the second molding after the first sealing portion is formed, it is assumed that a portion of the first sealing portion is melted by the heat of the molten resin during the second molding, and a force is applied to the first sealing portion by the pressure of the molten resin. Here, the configuration in which the recessed portion is formed in the portion to be sealed has the advantage that the position of the first sealing portion can be maintained by the recessed portion.However, the melted first sealing portion easily migrates into the recessed portion or the like, and there is a concern that the thickness of the first sealing portion covering the portion to be sealed is reduced due to the migration of the first sealing portion, or that a portion not covered by the first sealing portion is generated in the portion to be sealed and the sealing performance is deteriorated.On the other hand, according to the above configuration, since the thickness of the portion overlapping the recessed portion of the portion to be sealed is increased due to the protruding portion of the first sealing portion, even if the first sealing portion melts in the recessed portion and migrates due to heat or pressure in the second molding, a sealing thickness of the first sealing portion covering the portion to be sealed can be easily ensured, and the watertightness of the portion to be sealed by the first sealing portion can be maintained. Details of embodiments of the present disclosure

[0024] Specific examples of the present disclosure will be described below with reference to the figures. It should be noted that the present disclosure is not limited to these illustrative embodiments, but is indicated by the scope of the claims and is intended to encompass meanings equivalent to the scope of the claims and all modifications within the scope of the claims.

[0025] The present embodiment will be described with reference to Fig. 1 to 12 described.

[0026] For example, an electrical junction box 10 is arranged in a power supply path between a power supply, such as a battery, and a load, such as an on-board electrical component such as a light or a drive motor of a vehicle, which may be an electric vehicle, a hybrid vehicle, or a gasoline-powered vehicle. Although the electrical junction box 10 can be arranged in any orientation, the following description refers to the X and Y directions. Fig. 1 is referred to as forward or left and the Z-direction in Fig. 2 is called upwards.

[0027] As in Fig. 2, the electrical junction box 10 includes a circuit unit 20 and a heat dissipating member 70 disposed below the circuit unit 20 and dissipating heat of the circuit unit 20. The circuit unit 20 includes a circuit portion 21 formed by mounting electronic components 22 on bus bars 25A and 25B, first sealing portions 40 made of resin containing an adhesive component in close contact with sealing portions 34 of the bus bars 25A and 25B, and a resin portion 45 in close contact with the bus bars 25A and 25B and the first sealing portions 40, forming a casing of the circuit unit 20.

[0028] The circuit section 21 includes a plurality of electronic components 22 that generate heat when current flows through them, and a pair (a plurality) of bus bars 25A and 25B. In the present embodiment, the electronic components 22 are mounted side by side in the left-right direction on the back of the bus bars 25A and 25B, and they are switches such as FETs (Field Effect Transistors). The electronic components 22 are not limited to switches but may also be, for example, resistors, inductors, capacitors, or the like. Each electronic component 22 includes a plurality of contact legs connected to the bus bars 25A and 25B.One contact leg is provided in the region of the upper surface of the electronic component 22 and soldered to the bus bar 25A, the plurality of other contact legs protrude from the side surface of the electronic component 22 and are soldered to the bus bar 25B.

[0029] Each bus bar 25A and 25B is made of, for example, a flat plate material of metal, such as copper or a copper alloy, as shown in Fig. 3 and Fig. 4, has a shape corresponding to the current path and is plated on the outside. The pair of bus bars 25A and 25B are arranged with a gap between them. The bus bars 25A and 25B include terminal portions 26A and 26B, respectively, connectable to external terminals, and each has a main portion 28 on which the electronic components 22 are mounted, and a connecting portion 31 that connects the terminal portions 26A and 26B, respectively, to the respective main portion 28 in a hook-like manner (when viewed from the side).

[0030] The terminal portions 26A and 26B are rectangular, and screw insertion holes 27 through which the shaft portions of stud bolts SB are inserted are formed through the terminal portions 26A and 26B, respectively. The width dimension of each terminal portion 26B is larger than the width dimension of the connecting portion 31. One of the contact legs of each electronic component 22 is soldered to the main portion 28 of the bus bar 25A, and the other contact legs of the electronic components 22 are soldered to the main portion 28 of the bus bar 25B. A plurality of circular holes 28A are arranged at intervals in and penetrate the peripheral edge portions of the main portions 28. The holes 28A may be filled, for example, with the resin of the resin portion 45.

[0031] The connecting portions 31 have plate surfaces in a direction orthogonal to the plate surfaces of the terminal portions 26A and 26B and the main portions 28, and intermediate portions of the connecting portions 31 in the up-down direction (current flow direction) are portions 34 to be sealed, as shown in Fig. 4. Each of the sealed portions 34 is an area with which a later-described first sealing portion 40 is in close contact, and a groove-shaped groove portion 32 is provided over the entire circumference of the connecting portion 31. A plurality of through-holes 33 are formed in the bottom surface of the groove portion 32 and penetrate the groove portion 32. In the present embodiment, the plurality of through-holes 33 for each connecting portion 31 includes three circular through-holes 33 and two semicircular through-holes 33. The plurality of through-holes 33 are arranged at predetermined intervals in the left-right direction. The resin constituting the first sealing portion 40 penetrates and fills the through-holes 33 during the initial molding. The number of through-holes 33 can be changed as needed.For example, two circular holes 33 may be provided in each connecting section 31.

[0032] As in Fig. 2, a control circuit board 38 is arranged above the bus bars 25A and 25B so as to face the bus bars 25A and 25B. The control circuit board 38 is a printed circuit board in which conductive paths (not shown) made of copper foil or the like are formed on an insulating plate made of an insulating material using a circuit printing technique. The control circuit board 38 and the bus bars 25A and 25B are electrically connected to each other via rod-shaped terminal pins 36. The terminal pins 36 are inserted into the through holes of the bus bars 25A and 25B and the control circuit board 38, for example, and soldered. The bus bars 25A and 25B have a thickness (and a cross-sectional area) greater than that of the terminal pins 36.By increasing the thickness (and cross-sectional area) of the bus bars 25A and 25B, the thermal conductivity is increased and the electrical resistance is reduced, and the heat generated by the electronic components 22 diffuses into the bus bars 25A and 25B and is evenly distributed. The bus bars 25A and 25B are connected by soldering or the like to connector terminals (not shown) of a connector 80 (see FIG. Fig. 1) connected.

[0033] As in Fig. 8 and Fig. As shown in Fig. 9, the first sealing portions 40 include sealing main bodies 41 that are in close contact with the outer periphery of the sealed portions 34 of the bus bars 25A and 25B, and a plurality of protruding portions 43 that protrude from the sealing main bodies 41. Each sealing main body 41 overlies the sealed portion 34 with a substantially constant thickness and has filling portions 42 that fill the plurality of through-holes 33 at the positions of the through-holes 33 in the sealed portion 34. The protruding portions 43 are provided in a columnar shape at positions of the first sealing portion 40 that overlap the through-holes 33 (and the filling portions 42). The peripheral edge of the distal end of each of the protruding portions 43 is chamfered and rounded.The first sealing portions 40 serve as junction sealing materials for sealing the junctions between the bus bars 25A and 25B and comprise a polyester-based elastomer as the main component and an adhesive component. The polyester-based elastomer includes a reactive group to be bonded to an oxide layer of a metal, exhibits properties of both rubber and engineering plastics, and is excellent in, for example, flexibility, heat resistance, and thermal adhesion to a hard plastic. As the adhesive component, for example, silicone-based, epoxy-based, polyurethane-based, polyester-based, cyanoacrylate-based, acrylic-based, or the like adhesives can be used.

[0034] As in Fig. 2, the plastic portion 45 includes a plastic body 46 and a plastic cover 53 covering an opening 48A of the plastic body 46. The plastic body 46 includes a second sealing portion 50 in close contact with the outer surfaces of the first sealing portions 40 and the portions of the bus bars 25A and 25B other than the portions 34 to be sealed, a rectangular tubular peripheral wall portion 48 surrounding the portions of the main portions 28 of the bus bars 25A and 25B, and screw holding portions 47 holding the head portions of the stud bolts SB. The plastic portion 45 can be formed of various plastics such as polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), nylon, polypropylene (PP), or polyethylene (PE), and does not contain an adhesive component. The plastic of the plastic section 45 may also include a filler such as glass fiber.

[0035] The second sealing portion 50 is formed integrally with the peripheral wall portion 48 and the screw holding portions 47, extends along the plate surfaces of the bus bars 25A and 25B, and is in close contact with the outer surfaces of the bus bars 25A and 25B and the outer surfaces of the first sealing portions 40. In the second sealing portion 50, a plurality of exposing holes 51 for partially exposing the upper and lower surfaces of the main portions 28 are formed at positions overlapping the main portions 28 of the bus bars 25A and 25B.

[0036] The screw holding portions 47 are fixed to the bus bars 25A and 25B and expose the terminal portions 26A and 26B. In a state where the shaft portion of the stud bolt SB is inserted into the corresponding screw insertion hole 27, the stud bolt SB is held by the screw holding portion 47 and a terminal block 82, and the terminal portions 26A and 26B and external terminals (not shown) are fixed with nuts (not shown).

[0037] The plastic cover 53 is thermally bonded to the opening 48A at the upper end of the peripheral wall portion 48, and the space in the peripheral wall portion 48 is sealed by welding the plastic cover 53 to be sealed. The plastic cover 53 is provided with a mounting hole 54 in which a vent valve 57 is mounted. The vent valve 57 includes a vent film that allows air to pass through and prevents moisture from passing through, and is provided with fine holes that are waterproof and dustproof, providing ventilation.

[0038] As in Fig. As shown in Fig. 12, fixing portions 81 are fixed to the plastic body 46 at positions near the four corners of the plastic body 46, to be screwed and fixed to the heat dissipation member 70 with screws (not shown). The fixing portions 81 are formed, for example, from cylindrical metal collars into which the shaft portions of screws are inserted, and are embedded in the plastic body 46.

[0039] As in Fig. 2, the heat dissipation member 70 is made of a metallic material with high thermal conductivity, such as aluminum, an aluminum alloy, copper, a copper alloy, or the like, and a plurality of heat dissipation fins 75 are arranged on the underside of the heat dissipation member 70. A sealing member receiving groove 71, into which a sealing member 78 is fitted, and receiving chambers 72, in which the electronic components 22 are received, are formed on the underside of the heat dissipation member 70. The sealing member receiving groove 71 is annular and surrounds the main portions 28. A heat transfer material (not shown) is arranged between the upper surface of the heat dissipation member 70 and the underside of the circuit unit 20.As the heat transfer material, a plastic or the like having insulating property and high thermal conductivity is used, and for example, a heat dissipating adhesive made of an epoxy resin or the like can be used.

[0040] Next, a manufacturing method for the electrical junction box 10 will be described.

[0041] After the multiple busbars 25A and 25B ( Fig. 3) by punching and bending a metal plate by a press machine, a first sealing step is performed. In the first sealing step, the bus bars 25A and 25B are placed in a mold (not shown), a liquid polyester-based elastomer containing an adhesive component is injected into the mold, and the polyester-based elastomer is removed from the mold after solidification. As a result, a first molded product 60 is formed in which the first sealing portions 40 are formed on the bus bars 25A and 25B ( Fig. 6).

[0042] Next, a second sealing step is performed on the first molded product 60. In the second sealing step, the first molded product 60 and the terminal pins 36 are placed in a mold (not shown), and injection molding is performed in which a liquid resin is injected into the mold through an injection hole of the mold to form a second molded product 61 ( Fig. 11).

[0043] Here, the temperature of the resin injected in the second sealing step is higher than the melting point of the elastomer of the first sealing portion 40. Due to the heat of the resin, the first sealing portions 40 are partially melted and deformed, and the first sealing portions 40 flow slightly. Since the through-holes 33 are formed in the portions 34 to be sealed, the elastomer is easily melted and conveyed to the positions of the through-holes 33. In the present embodiment, since the thickness of the first sealing portions 40 is increased at the protruding portions 43 of the first sealing portions 40, the time until the first sealing portions 40 are melted can be extended.In addition, due to the thickness of the protruding portions 43, a reduction in the sealing ability due to melting and partial thinning of the first sealing portions 40 or generation of a portion of the portions 34 to be sealed not covered by the first sealing portions 40 can be prevented.

[0044] Next, a heat treatment step of heating the second cast product 61 is performed. In the heat treatment step, the elastomer of the first sealing portions 40 is remelted by heating, and an oxide layer of the metal and the reactive group are chemically bonded to each other, whereby the adhesion between the outer surfaces of the sealed portions 34 and the first sealing portions 40 can be improved.

[0045] The operation and effects of the present embodiment will now be described.

[0046] A circuit unit 20 includes: a circuit section 21 having terminal sections 26A and 26B connectable to external terminals, and main sections 28 on which electronic components 22 are mounted. Portions of the circuit section 21 between the main sections 28 and the terminal sections 26A and 26B are sealing portions 34 made of plate-shaped metals; first sealing portions 40 in close contact with the sealing portions 34 of the circuit section 21 and made of a resin containing an adhesive component;and a second sealing portion 50 made of a plastic and in close contact with the circuit portion 21 and an outer surface of the first sealing portions 40, wherein the portions to be sealed 34 each include through holes 33 (an example of recessed portions) allowing penetration of the first sealing portion 40, and outwardly projecting portions 43 are formed on an outer surface of a portion of each first sealing portion 40 that overlaps the through holes 33.;

[0047] According to the present embodiment, since the resin of the second sealing portion 50 and the resin-made first sealing portion 40 containing an adhesive component seal against the water flowing along the terminal portions 26A and 26B, the water can be prevented from invading from the terminal portions 26A and 26B side to the main portion 28 side. Furthermore, since the positions of the first sealing portions 40 with respect to the sealed portions 34 are easily maintained by the penetration of the first sealing portion 40 into the through-holes 33, positional displacement of the first sealing portion 40 can be prevented.

[0048] Note that when the second sealing portion 50 is formed by the second molding after the first sealing portions 40 are formed, it is assumed that a portion of the first sealing portions 40 is melted by the heat of the molten resin during the second molding, and a force is applied to the first sealing portions 40 by the pressure of the molten resin. Here, the configuration in which the through-holes 33 are formed in the sealed portions 34 has the advantage that the positions of the first sealing portions 40 can be held by the through-holes 33.However, the melted first sealing portions 40 easily migrate into the through holes 33, and there is a concern that the thickness of the first sealing portions 40 covering the sealed portions 34 is reduced due to the migration of the resin of the first sealing portions 40, or that a portion not covered by the first sealing portions 40 is generated in the sealed portions 34, and the sealing performance is deteriorated.On the other hand, according to the embodiment, since the thickness of the portions overlapping the through-holes 33 of the portions to be sealed 34 is increased due to the protruding portions 43 of the first sealing portions 40, even if the first sealing portions 40 melt in the through-holes 33 and migrate due to heat or pressure in the secondary molding, a sealing thickness of the first sealing portions 40 covering the portions to be sealed 34 can be easily ensured, and the deterioration of the sealing performance of the portions to be sealed 34 by the first sealing portions 40 can be prevented.

[0049] The width of the protruding portions 43 is larger than areas of the through holes 33 that overlap the protruding portions 43.

[0050] With this configuration, even if the first sealing portions 40 melt and migrate, a reduction in the sealing performance due to the size of the protruding area of ​​the protruding portions 43 can be prevented.

[0051] The through holes 33 and the projecting portions 43 are provided on both sides of the plate surface of the portions 34 to be sealed.

[0052] With this configuration, the reduction in sealing performance on both sides of the plate surface of the sealed portions 34 can be prevented. Furthermore, the thickness of the first sealing portions 40 can be increased in the areas of the through holes 33.

[0053] The terminal portions 26A and 26B each have a width dimension larger than that of a portion of the circuit portion 21 with which the first sealing portion 40 is in close contact.

[0054] With this configuration, in a configuration where it is not easy to attach a gasket made of rubber or the like due to the size of the width dimension of the terminal portions 26A and 26B, sealing can be achieved without using the gasket.

[0055] Portions between the terminal portions 26A and 26B and corresponding main portions 28 in the circuit portion 21 are bent in a hook shape.

[0056] With this configuration, in an embodiment in which there are concerns about adhesion to the sections 34 to be sealed during plastic molding due to the crank shape of the circuit section 21, the penetration of water from the outside can be prevented.

[0057] The circuit portion 21 includes plate-shaped metal bus bars 25A and 25B, the terminal portions 26A and 26B are formed on the bus bars 25A and 25B, respectively, and the first sealing portions 40 and the second sealing portion 50 are in close contact with the bus bars 25A and 25B.

[0058] This design can prevent water from penetrating the busbars 25A and 25B, through which comparatively large currents flow. Further embodiments

[0059] The technical teaching described in this patent specification is not limited to the embodiments described in the above description and the figures. The following embodiments are also included within the technical scope of the technical teaching described in this patent specification. (1) The first sealing portion 40 is made of a polyester-based elastomer containing an adhesive component, but the present invention is not limited thereto. The first sealing portion 40 may also be made of another plastic containing an adhesive component. (2) Printed circuit boards each having a conductor pattern made of copper foil or the like printed on an insulating plate may also be stacked to form a circuit section on the bus bars 25A and 25B. (3) The connecting portions 31 are configured to extend in a direction orthogonal to the terminal portions 26A and 26B and the main portions 28, but the present invention is not limited to this configuration. Another configuration may also be adopted, including connecting portions extending in a direction intersecting the terminal portions 26A and 26B and the main portions 28. (4) Although the bus bars 25A and 25B include terminal portions 26A and 26B, respectively, and the main portion 28 and the connecting portion 31, respectively, at least the portions 34 to be sealed by the first sealing portions 40 may be formed by the bus bars, and the terminal portions 26A and 26B and the like may also be formed by separate members. LIST OF REFERENCE SYMBOLS 10 electrical distribution box 20 circuit unit 21 Circuit section 22 electronic components 25A, 25B busbar 26A, 26B connection section 27 Screw insertion hole 28 Main Section 28A hole 31 connecting section 32 groove section 33 through hole 34 section to be sealed 36 connecting pins 38 Control circuit board 40 first sealing section 41 Sealing main body 42 Fill-in section 43 preceding section 45 plastic section 46 plastic bodies 47 Screw holding section 48 Perimeter wall section 48A opening 50 second sealing section 51 Excavation hole 53 Plastic cover 54 mounting hole 57 Ventilation valve 60 first cast product 61 second cast product 70 Heat dissipation element 71 Sealing element receiving groove 72 Recording Chamber 75 Heat dissipation fin 78 Sealing element 80 connectors 81 fastening section 82 terminal block SB stud screw

Claims

[1] Circuit unit (20), comprising: a circuit section (21) having a terminal section (26A, 26B) connectable to an external terminal and a main section (28) on which an electronic component (22) is mounted, wherein a section of the circuit section (21) between the main section (28) and the terminal section (26A, 26B) is a section to be sealed (34) made of a plate-shaped metal; a first sealing portion (40) which is in close contact with the portion (34) to be sealed of the circuit portion (21) and is made of a plastic containing an adhesive component; and a second sealing portion (50) made of a plastic and in close contact with the circuit portion (21) and an outer surface of the first sealing portion (40), wherein the section to be sealed (34) has a recessed section (33) which allows penetration of the first sealing section (40), an outwardly projecting portion (43) is formed on an outer surface of a portion of the first sealing portion (40) which overlaps the recessed portion (33), and the recessed portion (33) is a through hole penetrating the portion (34) to be sealed. [2] The circuit unit (20) according to claim 1, wherein the width of the protruding portion (43) is larger than an area of ​​the recessed portion (33) overlapping the protruding portion (43). [3] The circuit unit (20) according to claim 1 or 2, wherein the recessed portion (33) and the projecting portion (43) are provided on both sides of a plate surface of the portion to be sealed (34). [4] The circuit unit (20) according to any one of claims 1 to 3, wherein the terminal portion (26A, 26B) has a width dimension larger than that of a portion of the circuit portion (21) with which the first sealing portion (40) is in close contact. [5] The circuit unit (20) according to any one of claims 1 to 4, wherein a portion between the terminal portion (26A, 26B) and the main portion (28) in the circuit portion (21) is bent in a hook shape. [6] The circuit unit (20) according to any one of claims 1 to 5, wherein the circuit portion (21) comprises a plate-shaped bus bar (25A, 25B) made of metal, the terminal portion (26A, 26B) and the portion to be sealed (34) are formed on the bus bar (25A, 25B), and the first sealing portion (40) and the second sealing portion (50) are in close contact with the bus bar (25A, 25B). [7] Electrical distribution box, comprising: the circuit unit (20) according to one of claims 1 to 6; a heat dissipation element (70) resting on the circuit unit (20); and a sealing element sandwiched between the circuit unit (20) and the heat dissipation element (70). [8] Manufacturing method for a circuit unit (20), comprising: a first sealing step comprising bringing a first sealing portion (40) made of plastic, which contains an adhesive component, into close contact with a plate-shaped metal portion (34) to be sealed, which is provided in a circuit portion (21) between a terminal portion (26A, 26B) connectable to an external terminal and an electronic component, the circuit portion (21) comprising the terminal portion (26A, 26B) and a main portion (28) on which the electronic component (22) is mounted; and a second sealing step comprising forming a second sealing portion (50) by bringing plastic into close contact with the circuit portion (21) and the first sealing portion (40), wherein in the first sealing step, the plastic containing the adhesive component penetrates into a recessed portion (33) formed in the portion (34) to be sealed, and an outwardly projecting portion (43) is formed on the outer surface of the first sealing portion (40) in the region of the recessed portion (33), and the recessed portion (33) is a through hole penetrating the portion (34) to be sealed.

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