Electrical junction box and manufacturing method of electrical junction box

Abstract

To provide an electrical junction box capable of suppressing an increase in size while ensuring heat dissipation and a creepage distance.SOLUTION: An electrical junction box 10 includes a lower case 20 having a bottom part 21 provided with a through hole 23, an upper case 30 assembled to the lower case 20, a relay 40 housed inside the lower case 20 and the upper case 30, a bus bar 60 connected to the relay 40, and an insulating film 70 disposed on the bottom part 21 so as to close the through hole 23 and having an upper surface in contact with the bus bar 60, and a heat dissipation sheet 80 that is provided to pass through the through hole 23 while being in contact with the insulating film 70 and is in contact with an external cooling member 90. The insulating film 70 includes a creepage distance forming part 73 that is disposed on the bottom part 21 from an edge part 71 of the insulating film 70 to an opening end 23a of the through hole 23 to form a part of the creepage distance between the bus bar 60 and the external cooling member 90.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an electrical junction box and a method for manufacturing an electrical junction box. [Background technology]

[0002] Conventionally, there has been an electrical junction box that includes a resin case and an electric circuit component such as a relay held in the resin case (see, for example, Patent Document 1). A bus bar is connected to this electric circuit component. The bus bar is in contact with an external cooling member such as the chassis of the vehicle body via an insulating film and a heat dissipation sheet, thereby ensuring good heat dissipation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-79093 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the electrical junction box described above, the creepage distance between the bus bar and the external cooling member is the same as the thickness of the insulating film and the heat dissipation sheet, so there is a risk that the insulation between the bus bar and the external cooling member may not be ensured. Furthermore, for example, simply making the insulating film protrude significantly from the underside of the bus bar would result in an increase in the overall size of the box.

[0005] An object of the present disclosure is to provide an electrical junction box that can prevent an increase in size while ensuring heat dissipation properties and creepage distance, and a method for manufacturing the electrical junction box. [Means for solving the problem]

[0006] The electrical junction box of the present disclosure comprises a lower case having a bottom with a through hole, an upper case assembled to the lower case, electrical circuit components housed inside the lower case and the upper case, a bus bar connected to the electrical circuit components, an insulating film arranged on the bottom to cover the through hole and with its upper surface in contact with the bus bar, and a heat dissipation sheet arranged to pass through the through hole while in contact with the insulating film and in contact with an external cooling member, wherein the insulating film has a creepage distance forming portion that forms part of the creepage distance between the bus bar and the external cooling member by being arranged on the bottom from the edge of the insulating film to the open end of the through hole. [Effects of the Invention]

[0007] According to the electrical junction box and the manufacturing method of the electrical junction box of the present disclosure, it is possible to prevent the size from increasing while ensuring heat dissipation and creepage distance. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic cross-sectional view of an electrical junction box according to an embodiment. [Figure 2] FIG. 2 is a partially enlarged schematic cross-sectional view of the electrical junction box according to one embodiment. [Figure 3] FIG. 3 is a schematic cross-sectional view for explaining a method for manufacturing an electrical junction box according to one embodiment. [Figure 4] FIG. 4 is a partially enlarged schematic cross-sectional view of an electrical junction box according to a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described. The electrical junction box of the present disclosure comprises: [1] A lower case having a bottom with a through hole; an upper case assembled to the lower case; electric circuit components housed inside the lower case and the upper case; a bus bar connected to the electric circuit components; an insulating film arranged on the bottom so as to cover the through hole and having an upper surface in contact with the bus bar; and a heat dissipation sheet arranged to pass through the through hole while in contact with the insulating film and in contact with an external cooling member, wherein the insulating film has a creepage distance forming portion that forms a part of the creepage distance between the bus bar and the external cooling member by being arranged on the bottom from the edge of the insulating film to the open end of the through hole.

[0010] According to this configuration, the bus bar contacts the external cooling member via the insulating film and the heat dissipation sheet, ensuring good heat dissipation. Furthermore, the insulating film has a creepage distance-forming portion that constitutes part of the creepage distance between the bus bar and the external cooling member by being disposed on the bottom of the lower case from its edge to the opening end of the through-hole. This allows for a longer creepage distance while minimizing the size of the electrical junction box. That is, the insulating film has a creepage distance-forming portion extending from its edge to the opening end of the through-hole. This configuration allows for a longer creepage distance than, for example, a configuration in which an insulating film and a heat dissipation sheet are simply interposed between the bus bar and the external cooling member, resulting in a creepage distance equal to the thickness of the insulating film and the heat dissipation sheet. Furthermore, for example, if an insulating film is attached to the underside of the bus bar while exposing the bus bar below the through-hole, ensuring the creepage distance requires, for example, the insulating film to protrude significantly from the bus bar. This would result in, for example, a large amount of unnecessary space being created inside the lower case and the upper case, and would increase the size of the electrical junction box, but this configuration can be prevented.

[0011] [2] In the above [1], the bus bar may be in contact with the insulating film so as to be flush with an edge of the insulating film. With this configuration, the bus bar is in contact with the insulating film so as to be flush with the edge of the insulating film, which minimizes the creation of large, unnecessary spaces inside the lower and upper cases. In other words, compared to a configuration in which the insulating film protrudes from the bus bar, the size of the device can be reduced.

[0012] [3] In the above [1] or [2], the lower case may have a wall portion erected to face the edge of the insulating film so that a path including the creepage distance component is the creepage distance between the bus bar and the external cooling member.

[0013] According to this configuration, the lower case has a wall portion that faces the edge of the insulating film so that the path including the creepage distance forming portion becomes the creepage distance between the bus bar and the external cooling member, so there is no need for the lower case to protrude significantly from the bus bar, thereby preventing the device from becoming too large.

[0014] [4] In any one of [1] to [3] above, the electrical circuit components may be provided in a plurality, and fixing holes may be provided at positions between the electrical circuit components in the bottom portion, and the upper case may have fixing portions that pass through the fixing holes and are fixed to the external cooling member.

[0015] According to this configuration, fixing holes are provided in the bottom portion at positions between the electric circuit components, and the upper case has fixing portions that penetrate the fixing holes and are fixed to the external cooling member, so the electric junction box can be stably fixed to the external cooling member with a small number of fixing points. Furthermore, with this configuration, it is possible to prevent the creation of large, unnecessary spaces inside the lower and upper cases, even between the electric circuit components, and therefore it is possible to prevent the electric junction box from becoming larger.

[0016] [5] In any one of [1] to [4] above, a plurality of the electric circuit components may be provided, and the insulating film may have a plurality of component corresponding portions corresponding to each of the electric circuit components.

[0017] According to this configuration, the insulating film has a plurality of component-receiving portions corresponding to the respective electric circuit components, so the number of components can be reduced compared to a configuration in which the components are provided separately for each electric circuit component, which makes it easier to assemble the insulating film, for example.

[0018] The method for manufacturing an electrical junction box according to the present disclosure includes: [6] A method for manufacturing an electrical connection box according to any one of [1] to [5] above, comprising: a film fixing step of fixing the insulating film to the lower case; a circuit fixing step of fixing the electrical circuit components and the bus bar to the upper case; and a case assembling step of assembling the lower case and the upper case after the film fixing step and the circuit fixing step so that the bus bar and the insulating film come into contact with each other.

[0019] According to this method, an insulating film is fixed to the lower case in a film fixing process, and electrical circuit components and a bus bar are fixed to the upper case in a circuit fixing process. Then, after the film fixing process and the circuit fixing process, the lower case and the upper case are assembled in a case assembling process so that the bus bar and the insulating film are in contact with each other. This allows the electrical circuit components, the bus bar, and the insulating film to be housed inside the lower case and the upper case, and each component to be easily assembled in a desired position. For example, compared to a method in which the lower case is assembled to the upper case with the electrical circuit components, the bus bar, and the insulating film fixed to the upper case, this method allows the insulating film to be assembled accurately and easily in a desired position on the lower case. Furthermore, this configuration allows for suppressing size increase while ensuring heat dissipation and creepage distance.

[0020] [Details of the embodiments of the present disclosure] Specific examples of the present disclosure will be described below with reference to the drawings. In each drawing, for the convenience of explanation, some components may be exaggerated or simplified. Furthermore, the dimensional proportions of each part may differ from one drawing to another. Furthermore, the present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0021] (Configuration of electrical junction box 10) 1, the electrical junction box 10 includes a lower case 20, an upper case 30, electric circuit components such as a relay 40 and a fuse 50, a bus bar 60, an insulating film 70, and a heat dissipation sheet 80. The electrical junction box 10 of this embodiment is fixed to, for example, an external cooling member 90 provided in a vehicle. The external cooling member 90 may be, for example, an aluminum plate with high heat dissipation properties, or a water-cooled member through which cooling water is circulated.

[0022] (Configuration of the lower case 20) The lower case 20 is made of a resin material. The lower case 20 has a bottom 21 and a wall 22. The bottom 21 is formed in a plate shape. The bottom 21 is provided with a through hole 23 and a fixing hole 24. The through hole 23 is provided below the portions of the bottom 21 where the relay 40 and the fuse 50 are respectively disposed. The fixing hole 24 is provided at a position on the bottom 21 between the relay 40 and the fuse 50. Note that in FIG. 1 , the lower case 20 is illustrated as being divided into two portions, one disposed below the relay 40 and the other disposed below the fuse 50, with the fixing hole 24 sandwiched between them, but these portions are connected at a position not shown. The wall 22 is provided upright on the outer edge of the bottom 21 and the edge of the fixing hole 24.

[0023] (Configuration of upper case 30) The upper case 30 is made of a resin material. The upper case 30 is assembled to the lower case 20. The upper case 30 has a side wall 31, an upper wall 32, and a fixing portion 33. The side wall 31 is formed to cover the outside of the wall portion 22 of the lower case 20. The upper wall 32 is formed to connect the upper ends of the side walls 31 and cover the relay 40 and the fuse 50. The fixing portion 33 is formed so as to be able to pass through the fixing holes 24 of the lower case 20 and be fixed to the external cooling member 90. The fixing portion 33 in this embodiment has a screw hole 33a, and is fixed to the external cooling member 90 by a screw 34 that passes through the screw hole 33a and screws into the external cooling member 90.

[0024] (Configuration of relay 40, fuse 50 and bus bar 60) The relay 40 and the fuse 50 are electric circuit components housed inside the lower case 20 and the upper case 30. A bus bar 60 is connected to each of the relay 40 and the fuse 50. The bus bar 60 is a metal plate. The bus bar 60 extends downward below each of the relay 40 and the fuse 50. The bus bar 60 is also connected to other electric circuit components via other bus bars (not shown). Note that FIG. 1 illustrates one of the pair of bus bars 60 connected to the relay 40 being fixed by a screw 41. The relay 40 and the fuse 50 are also fixed to the upper case 30 by a fixing structure (not shown). The bus bar 60 is fixed to the relay 40 and the fuse 50, and thereby fixed to the upper case 30.

[0025] (Configuration of insulating film 70) The insulating film 70 is, for example, an insulating resin film. The insulating film 70 is disposed on the bottom 21 so as to cover the through-holes 23 of the lower case 20. The upper surface of the insulating film 70 is in contact with the bus bar 60. As shown in FIG. 2 , in this embodiment, the bus bar 60 is in contact with the insulating film 70 so as to be flush with an edge 71 of the insulating film 70. In other words, the insulating film 70 is configured to cover the entire lower surface of the bus bar 60 while not protruding from the bus bar 60 when viewed from above. Note that in FIG. 1 , the insulating film 70 is illustrated as being divided into two portions, one disposed below the relay 40 and the other disposed below the fuse 50, with the fixing holes 24 sandwiched therebetween; however, these portions are connected at a position not shown. That is, the insulating film 70 of this embodiment is a single film and has a plurality of component-corresponding portions 72 corresponding to the relays 40 and the fuse 50, respectively.

[0026] (Configuration of heat dissipation sheet 80) The heat dissipation sheet 80 is, for example, a thermally conductive silicone sheet. The heat dissipation sheets 80 are provided corresponding to the respective through-holes 23 of the lower case 20. The heat dissipation sheets 80 are provided so as to pass through the through-holes 23 of the lower case 20 while being in contact with the insulating film 70, and are in contact with the external cooling member 90. The heat dissipation sheet 80 is configured to be sandwiched between the insulating film 70 and the external cooling member 90 when the fixing portions 33 of the upper case 30 are fixed to the external cooling member 90 with the screws 34, i.e., when the electrical junction box 10 is fixed to the external cooling member 90.

[0027] 2, the insulating film 70 has a creepage distance forming portion 73 that is disposed on the bottom 21 from an edge 71 of the insulating film 70 to the opening end 23a of the through hole 23 and thereby forms part of the creepage distance between the bus bar 60 and the external cooling member 90. In other words, the insulating film 70 has the creepage distance forming portion 73 in a range H from the edge 71 of the insulating film 70 to the opening end 23a of the through hole 23. As shown in FIG. 1, the creepage distance forming portion 73 is provided in all positions on the insulating film 70 that are close to each of the bus bars 60.

[0028] Furthermore, the wall 22 of the lower case 20 is erected to face the edge 71 of the insulating film 70 so that the path including the creepage distance forming portion 73 becomes the creepage distance between the bus bar 60 and the external cooling member 90. That is, for example, if the gap between the lower case 20 and the external cooling member 90 is extremely small or they are in contact with each other and the height of the wall 22 is low, there is a risk that the creepage distance, i.e., the shortest distance along the surface of the insulator, will be a path that does not include the creepage distance forming portion 73. To prevent this, the position and height of the wall 22 are set so that the path including the creepage distance forming portion 73 becomes the creepage distance between the bus bar 60 and the external cooling member 90.

[0029] (Method of manufacturing the electrical junction box 10) Next, a method for manufacturing the electrical junction box 10 configured as above will be described. The manufacturing method of the electrical junction box 10 includes a film fixing step, a circuit fixing step, a case assembling step, and a heat dissipation sheet fixing step.

[0030] As shown in Fig. 3, in the film fixing step, the insulating film 70 is fixed to the lower case 20. More specifically, the insulating film 70 is fixed onto the bottom 21 so as to cover the through-hole 23 of the lower case 20. Note that Figs. 1 and 3 are end views that schematically show the cross section of the electrical junction box 10, but do not generally show the area behind the cut surface.

[0031] In the circuit fixing process, the relays 40 and fuses 50, each having a bus bar 60 fixed thereto, are fixed to the upper case 30. The circuit fixing process may be performed after the film fixing process, before the film fixing process, or simultaneously with the film fixing process.

[0032] Next, after the film fixing step and the circuit fixing step, in the case assembling step, the lower case 20 and the upper case 30 are assembled together so that the bus bars 60 and the insulating film 70 come into contact with each other.

[0033] In the heat dissipation sheet fixing process, the heat dissipation sheet 80 is fixed to the underside of the insulating film 70. The heat dissipation sheet fixing process may be performed after the case assembling process or may be performed before the case assembling process. In this manner, the manufacture of the electrical junction box 10 is completed.

[0034] Next, the effects of the above embodiment will be described below. (1) The busbar 60 contacts the external cooling member 90 via the insulating film 70 and the heat dissipation sheet 80, ensuring good heat dissipation. This suppresses temperature increases in the relays 40 and the fuses 50. The insulating film 70 is disposed on the bottom 21 of the lower case 20 from the edge 71 of the insulating film 70 to the opening end 23a of the through-hole 23, thereby providing a creepage distance component 73 that constitutes part of the creepage distance between the busbar 60 and the external cooling member 90. This prevents the device from becoming too large while still ensuring the creepage distance. That is, the insulating film 70 has the creepage distance component 73 in the range H from the edge 71 to the opening end 23a of the through-hole 23. This allows for a longer creepage distance than, for example, a configuration in which the insulating film 70 and the heat dissipation sheet 80 are simply interposed between the busbar 60 and the external cooling member 90, in which the creepage distance is the same as the thickness of the insulating film 70 and the heat dissipation sheet 80. 4, in the case where the insulating film 70 is attached to the lower surface of the bus bar 60 while the bus bar 60 is exposed below the through hole 23, it becomes necessary to make the insulating film 70 protrude significantly from the bus bar 60 in order to ensure the creepage distance. This would result in, for example, a large, unnecessary space K being created inside the lower case 20 and the upper case 30, and the electrical junction box 10 becoming larger, but this can be prevented.

[0035] (2) Because the bus bar 60 is in contact with the insulating film 70 so as to be flush with the edge 71 of the insulating film 70, it is possible to minimize the creation of large, unnecessary spaces inside the lower case 20 and the upper case 30. In other words, compared to a configuration in which the insulating film 70 protrudes from the bus bar 60, it is possible to prevent the case from becoming large.

[0036] (3) The lower case 20 has a wall portion 22 that stands facing the edge portion 71 of the insulating film 70 so that the path including the creepage distance forming portion 73 becomes the creepage distance between the bus bar 60 and the external cooling member 90. Therefore, it is not necessary to make the lower case 20 protrude significantly from the bus bar 60. This makes it possible to prevent the size from increasing.

[0037] (4) Fixing holes 24 are provided in the bottom 21 of the lower case 20 at a position between the relays 40 and the fuses 50, and the upper case 30 has fixing portions 33 that penetrate the fixing holes 24 and are fixed to the external cooling member 90. Therefore, the electrical junction box 10 can be stably fixed to the external cooling member 90 with a small number of fixing points. Furthermore, with this configuration, it is possible to prevent the creation of large, unnecessary spaces inside the lower case 20 and the upper case 30, even at positions between the relays 40 and the fuses 50, and therefore the electrical junction box 10 can be prevented from becoming larger.

[0038] (5) The insulating film 70 has a plurality of component-corresponding portions 72 corresponding to the relays 40 and the fuses 50, respectively. This reduces the number of components compared to a configuration in which the relays 40 and the fuses 50 are provided as separate components. This, for example, makes it easier to assemble the insulating film 70.

[0039] (6) In the above method, the relays 40, fuses 50, bus bars 60, and insulating film 70 can be housed inside the lower case 20 and the upper case 30, and each component can be easily assembled in a desired position. For example, compared to a method in which the lower case 20 is assembled to the upper case 30 with the relays 40, fuses 50, bus bars 60, and insulating film 70 fixed to the upper case 30, the insulating film 70 can be assembled to the lower case 20 in a desired position with high precision.

[0040] (Example of change) The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0041] In the above embodiment, the bus bar 60 is in contact with the insulating film 70 so as to be flush with the edge 71 of the insulating film 70, but this is not limited to this. For example, the insulating film 70 may protrude from the bus bar 60.

[0042] In the above embodiment, the lower case 20 has a wall portion 22 that stands upright to face the edge portion 71 of the insulating film 70, but this is not limited to this, and the lower case 20 may be configured without a wall portion 22.

[0043] In the above embodiment, the fixing holes 24 are provided in the lower case 20 at positions between the relays 40 and the fuses 50, and the upper case 30 has the fixing portions 33 that pass through the fixing holes 24 and are fixed to the external cooling member 90, but this is not limiting. In other words, the electrical junction box 10 may be fixed to the external cooling member 90 by other means.

[0044] In the above embodiment, the insulating film 70 has a plurality of component corresponding portions 72 corresponding to each of the relays 40 and the fuses 50, but this is not limited to this. For example, the insulating film 70 may be configured as a separate body for each of the relays 40 and the fuses 50.

[0045] In the above embodiment, the relay 40 and the fuse 50 are fixed to the upper case 30, but this is not limited to this. For example, the relay 40 and the fuse 50 may be fixed to the lower case 20 without using the upper case 30.

[0046] In the above embodiment, the electrical junction box 10 includes the relay 40 and the fuse 50 as electrical circuit components, but the types of electrical circuit components may be changed, and the number of electrical circuit components may be changed. For example, in Fig. 1, the electrical junction box 10 is illustrated as including one relay 40 and one fuse 50, but the electrical junction box 10 may be configured to include a plurality of relays 40 and a plurality of fuses 50.

[0047] In the above embodiment, the manufacturing method of the electrical connection box 10 includes a film fixing process, a circuit fixing process, a case assembling process, and a heat dissipation sheet fixing process, but is not limited to this, and the electrical connection box 10 may be manufactured by other manufacturing methods. [Explanation of symbols]

[0048] 10 Electrical junction box 20 Lower case 21 Bottom 22 Wall 23 Through hole 23a Open end 24 Fixing hole 30 Upper case 31 Side wall 32 Upper Wall 33 Fixed part 33a screw hole 34 Screw 40 Relay (electrical circuit component) 41 Screw 50 Fuses (electrical circuit components) 60 Busbar 70 Insulating film 71 Edge 72 Parts corresponding section 73 Creepage distance component 80 Heat dissipation sheet 90 External cooling member H range K space

Claims

1. a lower case having a bottom with a through hole; an upper case assembled to the lower case; Electric circuit components housed inside the lower case and the upper case; a bus bar connected to the electrical circuit component; an insulating film disposed on the bottom so as to cover the through-hole and having an upper surface in contact with the bus bar; a heat dissipation sheet that is in contact with the insulating film, passes through the through-hole, and is in contact with an external cooling member; the insulating film has a creepage distance forming portion that is disposed on the bottom from an edge of the insulating film to an open end of the through hole and that forms a part of a creepage distance between the bus bar and the external cooling member. Electrical junction box.

2. the bus bar is in contact with the insulating film so as to be flush with an edge of the insulating film; 2. The electrical junction box according to claim 1.

3. the lower case has a wall portion erected to face an edge of the insulating film so that a path including the creepage distance forming portion is set as the creepage distance between the bus bar and the external cooling member.

2. The electrical junction box according to claim 1.

4. a plurality of the electric circuit components; Fixing holes are provided at positions between the electric circuit components on the bottom portion, the upper case has a fixing portion that passes through the fixing hole and is fixed to the external cooling member; 2. The electrical junction box according to claim 1.

5. a plurality of the electric circuit components; the insulating film has a plurality of component corresponding portions corresponding to the electric circuit components, 2. The electrical junction box according to claim 1.

6. A method for manufacturing the electrical junction box according to claim 1, a film fixing step of fixing the insulating film to the lower case; a circuit fixing step of fixing the electric circuit components and the bus bars to the upper case; and a case assembling step of assembling the lower case and the upper case together so that the bus bar and the insulating film are in contact with each other after the film fixing step and the circuit fixing step. A manufacturing method for an electrical junction box.

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