Electrical junction box

Abstract

To provide an electric junction box that can dissipate heat generated by circuit components more quickly and appropriately with a simpler configuration.SOLUTION: An electric connection box includes: a case that accommodates a relay 10 and bus bars 11a, 11b connected to the relay 10. The electric junction box further includes an opening 522 formed in a bottom plate 521 of the case and a gap filler 53 that blocks the opening 522 and has a higher thermal conductivity than the case, wherein the bus bars 11a,11b are in contact with an inner surface 531 of the gap filler 53.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to an electrical junction box that houses circuit components. [Background technology]

[0002] 2. Description of the Related Art Conventionally, vehicles are equipped with electrical junction boxes that house circuit components such as relays.

[0003] Patent Document 1 discloses a power supply device that includes a relay having openable and closable contacts and an excitation coil that switches the open and closed states of the contacts, electrically connecting the contacts of the relay to a bus bar, and equipping the bus bar with a heat dissipation mechanism, thereby allowing the bus bar to serve as both a current path and a heat dissipation path. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-79093 Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, circuit components such as relays generate a lot of heat during operation and therefore need to be dissipated. There are two methods for dissipating heat: one is to conduct the heat generated by the circuit components to an external device via a housing that houses the circuit components, and the other is to conduct the heat directly to the external device without going through the housing.

[0006] Specifically, in the former method, a housing made of a heat-dissipating resin with better thermal conductivity than general resin is used to enhance the heat dissipation effect, while in the latter method, an opening is provided in the housing and the bus bar is exposed through the opening.

[0007] However, the former method has the problem of increased manufacturing costs due to the high cost of heat-dissipating resin, and the latter method has the problem of water entering the housing through gaps between the busbar and the housing caused by tolerances, differences in thermal expansion, etc. The power supply device of Patent Document 1 does not address such a problem and is unable to solve it.

[0008] The present invention has been made in consideration of the above circumstances, and its object is to provide an electrical junction box that can quickly and appropriately dissipate heat generated from circuit components with a simpler configuration. [Means for solving the problem]

[0009] An electrical connection box according to an embodiment of the present disclosure is an electrical connection box including a housing that houses circuit components and bus bars connected to the circuit components, and includes a through hole formed in one wall of the housing, and a heat conduction member that covers the through hole and has a higher thermal conductivity than the housing, and the bus bars are in contact with the inner surface of the heat conduction member. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to provide an electrical junction box that can quickly and appropriately dissipate heat generated from circuit components with a simpler configuration. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a perspective view showing an electrical junction box according to an embodiment of the present invention; [Figure 2] 1 is a perspective view showing a state in which an upper case is omitted in the electrical junction box according to the present embodiment. FIG. [Figure 3] FIG. 2 is a partial cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is an enlarged view showing the part surrounded by the dashed line in FIG. 3. [Figure 5] FIG. 4 is a cross-sectional view taken along line VV in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] [Description of the embodiment of the present invention] First, embodiments of the present disclosure will be listed and described. At least some of the embodiments described below may be combined in any desired manner.

[0013] (1) An electrical connection box according to an embodiment of the present disclosure is an electrical connection box including a housing that houses circuit components and bus bars connected to the circuit components, and includes a through hole formed in one wall of the housing, and a heat conductive member that covers the through hole and has a higher thermal conductivity than the housing, and the bus bars are in contact with the inner surface of the heat conductive member.

[0014] In this embodiment, the thermally conductive member having a higher thermal conductivity than the housing is provided to cover the through-hole formed in the housing, and the bus bar is in contact with the thermally conductive member. Therefore, heat generated from the circuit components is quickly transferred to the thermally conductive member via the bus bar, and can be dissipated to the outside of the housing more quickly than from other parts of the housing.

[0015] (2) In the electrical junction box according to the embodiment of the present disclosure, the heat conduction member is insulating.

[0016] In this embodiment, since the heat conduction member is insulating, malfunctions and other problems caused by the bus bar (circuit component) being electrically connected to other external components via the heat conduction member can be prevented.

[0017] (3) In the electrical junction box according to the embodiment of the present disclosure, the thermally conductive member is thicker than the thickness of the one wall.

[0018] In this embodiment, the thickness of the heat conduction member is greater than the thickness of the one wall, so that the heat conduction member protrudes further into the housing than the one wall, ensuring proper contact between the bus bar and the heat conduction member.

[0019] (4) In the electrical junction box according to the embodiment of the present disclosure, the outer surface of the heat conduction member is flush with the outer surface of the one wall.

[0020] In this embodiment, the outer surface of the heat conduction member is flush with the outer surface of the one wall, so there is no step between the outer surface of the heat conduction member and the outer surface of the one wall, and therefore the step does not interfere with attaching another device to the outer surface of the one wall of the housing.

[0021] (5) The electrical junction box according to the embodiment of the present disclosure includes an insulating sheet that covers the heat conductive member and the outer surface of the one wall up to the periphery of the heat conductive member.

[0022] In this embodiment, the insulating sheet covers the heat conduction member and the outer surface of the one wall up to the periphery of the heat conduction member. Therefore, even if the heat conduction member loses its insulating properties for some reason, such as a gap being formed between the heat conduction member and the one wall or a portion of the heat conduction member being lost, the insulation between the housing and other external components can be ensured and water can be prevented from entering the housing through such a gap or loss.

[0023] [Details of the embodiment of the present invention] An electrical junction box according to an embodiment of the present disclosure will be described below with reference to the drawings. Note that 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 of the claims.

[0024] In the following, this embodiment will be described using an example of an electrical junction box that houses a relay as a circuit component.

[0025] FIG. 1 is a perspective view showing an electrical junction box 100 according to this embodiment. The electrical junction box 100 includes a housing 50 that houses circuit components. The housing 50 is made of, for example, metal or resin, and houses a relay 10 (described later). The electrical junction box 100 is attached to the outside of a battery pack 200 of an EV (Electric Vehicle) (see FIG. 4), for example. The battery pack 200 is provided with a cooling mechanism (not shown) on the outside.

[0026] Fig. 2 is a perspective view showing the electrical junction box 100 according to this embodiment without the upper case 51, Fig. 3 is a partial cross-sectional view taken along line III-III in Fig. 1, Fig. 4 is an enlarged view showing the portion surrounded by the dashed line in Fig. 3, and Fig. 5 is a cross-sectional view taken along line VV in Fig. 3. For ease of explanation, the battery pack 200 is shown by a dashed line in Fig. 4.

[0027] In the electrical junction box 100, the housing 50 is made up of an upper case 51 to which the relay 10 is fixed, and a lower case 52 (described below) that is covered by the upper case 51. The electrical junction box 100 is attached so that a bottom plate 521 of the lower case 52 comes into contact with the battery pack 200.

[0028] As will be described later, relay 10 is fixed to ceiling plate 513 of upper case 51. Bus bars 11a and 11b are provided near an inner surface 523 of bottom plate 521 (one wall) of lower case 52, which faces ceiling plate 513. Portions of bus bars 11a and 11b are interposed between relay 10 and inner surface 523. Hereinafter, bus bars 11a and 11b will also be referred to as bus bars 11 for convenience.

[0029] For example, the relay 10 is switched to an ON state when the vehicle is running, and is switched to an OFF state when the vehicle is not running. The relay 10 has a rectangular box shape, and one surface 102 of the relay 10 is disposed so as to face an inner surface 523 (bus bar 11) of a bottom plate 521.

[0030] The relay 10 has four side surfaces that rise perpendicularly from the four edges of the first surface 102, and a terminal 101 is provided on one of the side surfaces 107, as described below. That is, the relay 10 is provided so that the first surface 102 faces the inner surface 523, and the side surface 107 intersects with the inner surface 523.

[0031] The side surface 107 is a rectangle with its longitudinal direction being the direction in which the ceiling plate 513 and the bottom plate 521 face each other (hereinafter referred to as the vertical direction). Two terminals 101 are provided on the side surface 107. The two terminals 101 are arranged side by side in a direction intersecting the vertical direction (hereinafter referred to as the horizontal direction). The two terminals 101 are connected to the bus bar 11. Only one terminal 101 is shown in FIG. 3.

[0032] Each terminal 101 has a cylindrical shape, and most of it is embedded inside the relay 10, with only one end exposed on the side surface 107. A screw thread is formed on the inner peripheral surface of each terminal 101, and the terminal 101 is screwed onto a bolt 105 (see FIGS. 3 and 5).

[0033] Furthermore, a partition plate 103 is provided on a side surface 107 of the relay 10 between the two terminals 101. The two terminals 101 are separated by the partition plate 103. The partition plate 103 is generally rectangular and extends vertically.

[0034] The relay 10 has two connecting pieces 106 on the other surface 104 opposite the one surface 102 (see FIG. 2). The connecting pieces 106 are respectively connected to two opposing edges of the other surface 104. The two connecting pieces 106 are provided diagonally from each other and extend from the edges of the other surface 104 along the surface direction of the other surface 104. A through hole 108 is formed in the connecting piece 106, passing through the connecting piece 106 in the vertical direction. The relay 10 is fixed to the upper case 51 by inserting a bolt (not shown) into the through hole 108 and screwing it into a screw hole provided in, for example, a ceiling panel 513 of the upper case 51.

[0035] The bus bar 11 is made of, for example, a metal plate with good conductivity. One of the two terminals 101 of the relay 10 is connected to a bus bar 11a, and the other terminal 101 is connected to a bus bar 11b.

[0036] The busbar 11a has a flat portion 111a that faces one surface 102 of the relay 10 and an inner surface 523 of the bottom plate 521. A contact portion 112a and a fixing portion 113a that extend in the vertical direction are connected to two opposing edges of the flat portion 111a, respectively.

[0037] Contact portion 112a has a rectangular plate shape with the longitudinal direction being the vertical direction, and is disposed near side surface 107 of relay 10. Contact portion 112a extends along side surface 107, and has through-hole 114 formed in the approximate center. Bolt 105 is inserted through through-hole 114 and screwed into one terminal 101, thereby fixing contact portion 112a (bus bar 11a) to one terminal 101 and electrically connecting them.

[0038] The end of the fixed portion 113a is bent in parallel with the bottom plate 521, and a through-hole 115a (see FIG. 2) used for fixing the fixed portion 113a is formed in the end.

[0039] Busbar 11b has flat portion 111b facing inner surface 523 of bottom plate 521. Furthermore, contact portion 112b and fixing portion 113b extending in the vertical direction are connected to two opposing edges of flat portion 111b, respectively.

[0040] Contact portion 112b has a rectangular plate shape with its longitudinal direction extending vertically, and is disposed near side surface 107 of relay 10. Contact portion 112b extends along side surface 107, and has a through-hole (not shown) formed in the approximate center. By inserting bolt 105 into the through-hole and screwing it into the other terminal 101, contact portion 112b (bus bar 11b) is fixed to and electrically connected to the other terminal 101 (see FIG. 3).

[0041] Moreover, the end of the fixing portion 113b is bent in parallel with the bottom plate 521, and a through-hole 115b (see FIG. 2) used for fixing the fixing portion 113b is formed in the end.

[0042] Pressing portions 13 protrude from ceiling plate 513 of upper case 51 and press bus bars 11 against bottom plate 521. Pressing portions 13 extend vertically from ceiling plate 513 and press flat portions 111a of bus bars 11a and flat portions 111b of bus bars 11b against bottom plate 521.

[0043] For example, pressing portion 13 is formed integrally with upper case 51, and when electrical junction box 100 is completely assembled, the tip of pressing portion 13 always contacts flat portions 111a and 111b, pressing bus bars 11a and 11b against bottom plate 521.

[0044] Meanwhile, relay 10 generates a large amount of heat during operation. This heat has an adverse effect on electrical components around relay 10 and may even cause the electrical components to malfunction, so it is necessary to dissipate the heat. Methods for dissipating the heat generated by relay 10 include a method in which the heat generated by relay 10 is conducted to an external device via a housing that houses relay 10 for cooling (hereinafter referred to as an indirect conduction method), and a method in which the heat is conducted directly to an external device for cooling without going through the housing (hereinafter referred to as a direct conduction method).

[0045] The indirect conduction method uses a housing made of a heat-dissipating resin to enhance the heat dissipation effect, while the direct conduction method employs a configuration in which an opening is provided in the housing and the bus bar is exposed through the opening.

[0046] However, in the case of the indirect conduction method, there is a problem that the heat dissipation resin is expensive, which increases the manufacturing cost of the product, and in the case of the direct conduction method, there is a problem that gaps occur at the boundary between the bus bar and the casing due to tolerances, differences in thermal expansion, etc., and water can enter the casing through these gaps.

[0047] In contrast, the electrical junction box 100 according to this embodiment has a simple configuration and can quickly and appropriately dissipate the heat generated in the relay 10. This will be described in detail below.

[0048] The electrical junction box 100 according to this embodiment includes a gap feeler 53 (thermal conductive member) on the bottom plate 521 of the lower case 52, which transfers heat generated in the relay 10 to the battery pack 200 side via the bus bar 11. The gap feeler 53 has a higher thermal conductivity than the lower case 52.

[0049] An opening 522 penetrating the inside and outside of the lower case 52 is formed in the bottom plate 521 of the lower case 52 in the vertical direction in an area corresponding to at least the flat portions 111a and 111b of the bus bar 11. The opening 522 is, for example, rectangular.

[0050] Gap feeler 53 (thermal conductive material) is applied inside opening 522. Gap feeler 53 is insulating. Gap feeler 53 is a spreadable gap feeler that hardens over time. That is, gap feeler 53 is semi-solid when applied, but hardens over time after application. The semi-solid gap feeler 53 is applied so as to close opening 522. Furthermore, gap feeler 53 is applied to a thickness greater than the thickness of bottom plate 521 of lower case 52.

[0051] Therefore, the gap feeler 53 after hardening is thicker than the bottom plate 521 and has a rectangular plate shape that follows the shape of the opening 522.

[0052] As described above, the semi-solid gap feeler 53 is applied inside the opening 522. In other words, the hardened gap feeler 53 has a rectangular plate shape as described above and closes the opening 522. The outer surface 532 of the gap feeler 53 is flush with the outer surface 524 of the bottom plate 521 of the lower case 52. Furthermore, as described above, the gap feeler 53 is thicker than the bottom plate 521, and therefore the gap feeler 53 protrudes inward from the inner surface 523 of the bottom plate 521.

[0053] The busbar 11 is in contact with the inner surface 531 of the gap feeler 53. More specifically, the flat portion 111a of the busbar 11a and the flat portion 111b of the busbar 11b are in pressure contact with the inner surface 531 of the gap feeler 53.

[0054] An insulating sheet 54 is laid on an outer surface 532 of the gap feeler 53. The insulating sheet 54 covers the gap feeler 53 and the bottom plate 521 of the lower case 52 up to the periphery of the gap feeler 53. That is, the insulating sheet 54 is rectangular and larger than the gap feeler 53, and is laid so as to cover up to the boundary between the gap feeler 53 and the bottom plate 521 of the lower case 52. The outer surface of the insulating sheet 54 comes into contact with, for example, the battery pack 200 of the EV.

[0055] A method for applying the gap feeler 53 to the electrical junction box 100 according to this embodiment will be described. First, the insulating sheet 54 is attached to the opening 522 from the outside of the bottom plate 521 of the lower case 52. Then, with the lower case 52 (bottom plate 521) side facing up and the insulating sheet 54 side facing down, semi-solid gap feeler 53 is applied to the inner surface of the insulating sheet 54 from the inside of the bottom plate 521. As described above, the gap feeler 53 is applied so that it is thicker than the bottom plate 521 and so as to close the opening 522.

[0056] When the application of gap feeler 53 is completed as described above, upper case 51 incorporating busbar 11 and relay 10 and lower case 52 are assembled before gap feeler 53 hardens. At this time, flat portions 111a and 111b of busbar 11 are pressed against semi-solid gap feeler 53.

[0057] In the electric junction box 100 of this embodiment having such a configuration, when heat is generated in the relay 10 during energization, the heat from the relay 10 is quickly conducted to the gap feeler 53 via the bus bar 11. As described above, the gap feeler 53 is in contact with the battery pack 200 via the insulating sheet 54, and therefore the heat conducted to the gap feeler 53 is cooled by the cooling mechanism of the battery pack 200.

[0058] As described above, the electrical junction box 100 of this embodiment does not use an expensive heat-dissipating resin housing, thereby reducing the manufacturing cost of the product. Furthermore, the heat from the relay 10 is conducted to the battery pack 200 not through the bottom plate 521 of the lower case 52 but through the gap feeler 53, which has a higher thermal conductivity than the bottom plate 521, so that the heat from the relay 10 can be dissipated quickly and effectively.

[0059] Furthermore, in the electrical junction box 100 of this embodiment, a fluid, semi-solid gap feeler 53 is applied instead of using a solid member, so that after hardening, a gap is unlikely to occur between the gap feeler 53 and the bottom plate 521 of the lower case 52. This makes it possible to prevent water from entering the accommodating housing 50 through such a gap.

[0060] Furthermore, in the electrical junction box 100 of this embodiment, as described above, the insulating sheet 54 covers the gap feeler 53 and the bottom plate 521 up to the periphery of the gap feeler 53. Therefore, even if a gap occurs between the gap feeler 53 and the bottom plate 521, the gap is blocked by the insulating sheet 54, and water can be prevented from entering the accommodating housing 50 through the gap.

[0061] Furthermore, in the electrical connection box 100 of this embodiment, as described above, the outer surface 532 of the gap feeler 53 is flush with the outer surface 524 of the bottom plate 521, so there is no step between the gap feeler 53 and the bottom plate 521, and the adhesion between the gap feeler 53 and the bottom plate 521 and the insulating sheet 54 can be improved.

[0062] Furthermore, in the electrical junction box 100 of this embodiment, as described above, the upper case 51 and the lower case 52 are assembled before the gap feeler 53 hardens, and the flat portions 111a and 111b of the bus bar 11 come into contact with the semi-solid gap feeler 53. At this time, the semi-solid gap feeler 53 can freely deform in the vertical and horizontal directions, so that the tolerances related to the stacking of the gap feeler 53 and the bus bar 11 are absorbed.

[0063] As described above, the semi-solid gap feeler 53 comes into contact with the flat portions 111a, 111b of the bus bar 11, so that the contact surface between the hardened gap feeler 53 and the flat portions 111a, 111b can be maximized, and the adhesive force of the hardened gap feeler 53 can maintain contact between the gap feeler 53 and the flat portions 111a, 111b.

[0064] Although the above description has been given using the relay 10 as an example of a circuit component that generates heat when activated, the present invention is not limited to this and can, of course, be applied to other circuit components such as semiconductor switches.

[0065] The embodiments disclosed herein are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the claims, not by the above meaning, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0066] 10 Relay (circuit component) 11, 11a, 11b busbars 13 Pressing section 50 Containment Case 51 Upper Case 52 Lower Case 53 Gap feeler (thermal conductive material) 54 Insulation sheet 100 Electrical junction box 101 terminal 102 one side 103 Partition 105 volts 106 Continuous piece 107 Side 108 Through Hole 111a,111b flat part 112a,112b Contact part 113a,113b Fixed part 114 Through hole 115a,115b through hole 513 Ceiling Panel 521 Bottom plate 522 Opening 523 Inner surface 524 External surface 531 Inner surface 532 External surface

Claims

1. An electrical connection box including a housing that houses circuit components and bus bars connected to the circuit components, a through hole formed in one wall of the housing; a heat conduction member that closes the through hole and has a higher thermal conductivity than the housing, the bus bar is in contact with an inner surface of the heat conduction member; an electrical junction box including an insulating sheet covering the heat conducting member and the outer surface of the one wall up to the periphery of the heat conducting member;

2. 2. The electrical junction box according to claim 1, wherein the heat conducting member is insulating.

3. 3. The electrical junction box according to claim 1, wherein the heat conducting member has a thickness greater than that of the one wall.

4. 4. The electrical junction box according to claim 1, wherein an outer surface of the heat conducting member is flush with an outer surface of the one wall.

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