Electrical junction box

Abstract

To provide an electrical junction box which can secure the heat dissipation within a metal housing and can protect a busbar from infiltration of a foreign body through a housing hole at the same time.SOLUTION: A relay unit 8 of an electrical junction box 1 includes: a resin component 14 for forming the body of the relay unit 8, a relay 13 being attached to the resin component; and a bus bar 26 attached to the resin component 14 and used as a wiring of the resin component 14. The metal housing 2 has a housing hole 30 attached to the resin component 14, the housing hole being used for drawing an electric wire 7 electrically connected to the busbar 26 to the outside. The resin component 14 has a heat dissipation hole 34 for dissipating heat of the relay unit 8 generated when electricity is flown in the heat unit 8. The heat dissipation hole 34 has a step part 38 located in the back when viewed from the housing hole 30 in at least a part of a hole periphery edge.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an electrical connection box.

Background Art

[0002] Conventionally, as disclosed in Patent Document 1, an electrical connection box that relays a plurality of shielded electric wires with a relay, a fuse, or the like is well known. The electrical connection box of Patent Document 1 includes a box body having an upper case closed by a cover and a lower case attached to the back surface of the upper case. The lower case has a bus bar that connects a plurality of shielded electric wires housed in the box body from an electric wire outlet formed in the wall surface of the upper case. The plurality of shielded electric wires are arranged on the upper surface of the upper case, and the terminals at the tips are fixed to the bus bar of the lower case by a fastening structure of bolts and nuts.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the case of a shielded electric wire through which a high-voltage current flows, since a relay or a fuse generates heat, the inside of the box body tends to become high temperature. Further, in the case of an electrical connection box having an opening such as an electric wire outlet in the box body, even if a foreign object such as a wire enters through the opening such as the electric wire outlet, it is necessary to protect the bus bar so that this foreign object does not come into contact with the bus bar. Therefore, it has been desired to develop a technology that can achieve both ensuring heat dissipation inside the box body and protecting against foreign object intrusion from the opening of the box body.

[0005] An object of the present disclosure is to provide an electrical connection box capable of achieving both ensuring heat dissipation inside a metal housing and protecting a bus bar against foreign object intrusion from a housing hole.

Means for Solving the Problem

[0006] The electrical connection box for solving the above problem has a configuration in which a relay unit used for relaying the connection of electric wires is housed inside a metal housing. The relay unit has a resin component that forms the main body of the relay unit and to which at least a relay is attached, and a bus bar that is attached to the resin component and used as wiring in the resin component. The metal housing has a housing hole for drawing out an electric wire of a connector attached to the resin component and electrically connected to the bus bar to the outside. The resin component has a heat dissipation hole for dissipating heat generated when the relay unit is energized. The heat dissipation hole has a stepped portion located deeper when viewed from the housing hole at at least a part of the hole periphery.

Effect of the Invention

[0007] The present disclosure can achieve both ensuring heat dissipation inside the metal housing and protecting the bus bar against foreign matter intrusion from the housing hole.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Best Mode for Carrying Out the Invention

[0009] First, embodiments of the present disclosure will be listed and described. [1] The electrical connection box of the present disclosure has a configuration in which a relay unit used for relaying the connection of electric wires is housed inside a metal housing. The relay unit includes a resin component that forms the main body of the relay unit and to which at least a relay is attached, and a bus bar that is attached to the resin component and used as wiring in the resin component. The metal housing has a housing hole for drawing out an electric wire of a connector attached to the resin component and electrically connected to the bus bar to the outside. The resin component has a heat dissipation hole for dissipating heat of the relay unit generated when the relay unit is energized. The heat dissipation hole has a stepped portion located deeper when viewed from the housing hole at at least a part of the hole periphery.

[0010] According to this configuration, since the heat dissipation hole is formed in the resin component, it is possible to provide a path for heat dissipation inside the metal housing. Therefore, it is possible to release the heat generated in the relay unit from the housing hole to the outside of the metal housing through the heat dissipation hole. Further, even if a foreign object such as a wire that has entered from the housing hole tries to enter the inside of the resin component from the heat dissipation hole, it is possible to stop the tip of the foreign object by the stepped portion of the heat dissipation hole. Therefore, the possibility that a foreign object that has entered from the housing hole comes into contact with the bus bar inside the resin component is reduced. As described above, it is possible to achieve both ensuring heat dissipation in the metal housing and protecting the bus bar against intrusion of foreign objects from the housing hole.

[0011] [2] In the above [1], the heat dissipation hole has a circumferential protruding wall at the hole periphery disposed on the surface of the resin component, and the stepped portion is formed inside the heat dissipation hole having the protruding wall. According to this configuration, it is possible to catch and stop a foreign object such as a wire that has entered from the housing hole with the protruding wall. Therefore, it is possible to further suppress the intrusion of foreign objects into the heat dissipation hole.

[0012] [3] In [1] or [2] above, the heat dissipation holes are arranged at positions close to the relay. According to this configuration, it is possible to smoothly circulate the heat dissipated from the relay through the nearby heat dissipation holes. Therefore, it further contributes to ensuring heat dissipation within the metal housing.

[0013] [4] In any one of [1] to [3] above, the heat dissipation holes are arranged at positions close to the housing holes. According to this configuration, it is possible to smoothly discharge the heat of the heat dissipation holes from the housing holes to the outside of the metal housing. Therefore, it further contributes to ensuring heat dissipation within the metal housing.

[0014] [5] In any one of [1] to [4] above, the heat dissipation holes are arranged at positions lower than the lower end of the hole of the housing hole in the height direction of the metal housing. According to this configuration, it is possible to make the separation distance from the housing hole to the heat dissipation hole as long as possible. Therefore, it is possible to further suppress the intrusion of foreign matter into the heat dissipation holes.

[0015] [Details of Embodiments of the Present Disclosure] Specific examples of the present disclosure will be described below with reference to the drawings. Note that the present invention is not limited to these examples, and is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. In each drawing, for convenience of explanation, a part of the configuration may be exaggerated or simplified. Also, the dimensional ratios of each part may be different from the actual ones.

[0016] (Electrical Connection Box 1) As shown in FIG. 1, the electrical connection box 1 includes a metal housing 2 having noise resistance as the housing of the electrical connection box 1. The metal housing 2 has, for example, a housing body 3 forming the main body portion of the metal housing 2 and an upper cover 4 that closes the opening 5 (see FIG. 2 etc.) of the housing body 3. The housing body 3 is made of, for example, aluminum. The housing body 3 has an opening at the upper part, for example.

[0017] The upper cover 4 is formed, for example, in the shape of a rectangular plate. The upper cover 4 is made of, for example, iron. The upper cover 4 is fixed to the housing body 3 by fastening members 6 such as a plurality of screws at the four corners of the upper cover 4, for example.

[0018] As shown in FIGS. 2 and 3, in the electrical connection box 1, a relay unit 8 used for the relay connection of the electric wire 7 is housed inside the metal housing 2. Thus, the electrical connection box 1 is a member that relays an electrical component connected to one electric wire 7 (in this example, the first electric wire 9) and an electrical component connected to the other electric wire 7 (in this example, the second electric wire 10). The electric wire 7 is, for example, a high-voltage electric wire. When an overvoltage or overcurrent is applied to the electric wire 7, for example, the electrical connection box 1 protects the electric circuit by cutting off the electric circuit connected to the electric wire 7 by the relay unit 8.

[0019] (Relay unit 8) As shown in FIGS. 2 and 3, the relay unit 8 has a resin part 14 that forms the main body of the relay unit 8 and to which at least a relay 13 is attached. The resin part 14 is a member for attaching and supporting electronic components mounted on the relay unit 8. The resin part 14 has, for example, a resin part main body 15 that forms the main body of the resin part 14 and a protective cover 16 that protects the back surface of the resin part main body 15. The aforementioned relay 13 and a connector 17 provided at the tip of the electric wire 7 (see FIG. 3) are attached to the resin part main body 15. The resin part main body 15 is formed, for example, in a bottomless hollow shape. The protective cover 16 is fixed to the bottom of the resin part main body 15 by a plurality of screws or the like (not shown), for example. The resin part 14 is fixed to the metal housing 2 (in this example, the housing body 3) by fastening members 18 such as a plurality of screws, for example.

[0020] Relay 13 is mounted on a relay mounting portion 20 formed at the center in the width direction (Y-axis direction in FIG. 3) of the resin component 14 on the upper surface of the resin component 14. The relay 13 turns on and off an electrical circuit to be relayed by contacts (not shown) provided in the relay housing. The relay 13 cuts off the electrical circuit, for example, when the electrical circuit to be relayed becomes overvoltage or overcurrent.

[0021] The connector 17 includes a first connector 21 provided at the tip of the first electric wire 9 and a second connector 22 provided at the tip of the second electric wire 10. The first connector 21 is mounted on a first connector mounting portion 23 disposed at one end in the width direction (Y-axis direction in FIG. 3) of the resin component 14 on the upper surface of the resin component 14. The second connector 22 is mounted on a second connector mounting portion 24 disposed at the other end in the width direction (Y-axis direction in FIG. 3) of the resin component 14 on the upper surface of the resin component 14.

[0022] The relay unit 8 has a bus bar 26 that is mounted on the resin component 14 and used as wiring in the resin component 14. The bus bar 26 is, for example, wiring for flowing a large current. The bus bar 26 is attached and fixed to the back surface of the resin component main body 15 by, for example, screws (not shown). In the case of this example, the bus bar 26 includes, for example, a first bus bar 27 that electrically connects the relay 13 and the first connector 21, and a second bus bar 28 that electrically connects the relay 13 and the second connector 22.

[0023] The first electric wire 9 is connected to one terminal of the relay 13 via the first connector 21 and the first bus bar 27. The second electric wire 10 is connected to the other terminal of the relay 13 via the second connector 22 and the second bus bar 28. Thus, the relay unit 8 has, for example, an electrical path from the first electric wire 9 to the first connector 21, the first bus bar 27, the relay 13, the second bus bar 28, the second connector 22, and the second electric wire 10 in sequence.

[0024] Note that the relay unit 8 may have a plurality of pairs of electric wires 7. In this case, the relay unit 8 is not limited to having only one relay 13, and may have a plurality of relays 13. The relay unit 8 may have a fuse as a countermeasure against overcurrent of the electric wire 7. That is, the relay unit 8 may have both the relay 13 and the fuse. Further, the number of bus bars 26 may be appropriately changed according to the number of relays 13 and fuses provided in the relay unit 8.

[0025] (Housing hole 30) As shown in FIGS. 1 to 3, the metal housing 2 has a housing hole 30 for drawing out the electric wires 7 (in this example, the first electric wire 9 and the second electric wire 10) attached to the resin component 14 and electrically connected to the bus bar 26 to the outside. The housing hole 30 is formed, for example, by notching an end portion in the height direction (the +Z-axis direction in FIG. 1 etc.) of the side wall of the housing main body 3. In the case of this example, the housing hole 30 includes, for example, a first housing hole 31 for drawing out the first electric wire 9 to the outside of the housing and a second housing hole 32 for drawing out the second electric wire 10 to the outside of the housing. The housing hole 30 ventilates the air inside the metal housing 2 in order to suppress the temperature rise inside the metal housing 2.

[0026] (Heat dissipation measures in the resin component 14) As shown in FIGS. 2 to 4, the resin component 14 has a heat dissipation hole 34 for dissipating the heat of the relay unit 8 generated when the relay unit 8 is energized. The heat dissipation hole 34 is a hole that communicates the internal space region 35 of the resin component 14 to the outside of the resin component 14. The heat dissipation hole 34 has a circumferential protruding wall 36 at the hole periphery arranged on the surface of the resin component 14. The heat dissipation hole 34 is formed in a rectangular shape when viewed from the hole opening direction (the Z-axis direction in FIGS. 2 and 4 etc.) (see FIG. 4). The heat dissipation hole 34 may be one or a plurality. In the space region 35, for example, a bus bar 26 and a fuse (not shown) are arranged.

[0027] As shown in FIGS. 2 and 3, the heat radiation holes 34 are preferably arranged, for example, at positions close to the relay 13. This is because the relay 13 is likely to become hot, and thus the heat generated by the relay 13 is efficiently radiated through the heat radiation holes 34. In particular, the heat radiation holes 34 are preferably arranged above the bus bar 26 in the height direction (Z-axis direction in FIG. 2, etc.) of the resin component 14. Note that arranging the heat radiation holes 34 at positions close to the relay 13 means, for example, arranging the heat radiation holes 34 right beside the relay mounting portion 20.

[0028] Also, the heat radiation holes 34 are preferably arranged, for example, at positions close to the housing hole 30. This is because the heat from the heat radiation holes 34 is efficiently discharged to the outside of the housing through the housing hole 30. Note that arranging the heat radiation holes 34 at positions close to the housing hole 30 means, for example, arranging the heat radiation holes 34 at positions closer to the housing hole 30 than the center in the depth direction (X-axis direction in FIG. 2, etc.) of the resin component 14.

[0029] As shown in FIG. 2, the heat radiation holes 34 are set at a height having a predetermined distance Ha from the housing hole 30 in the height direction (Z-axis direction in FIG. 2) of the metal housing 2. That is, the heat radiation holes 34 are arranged at positions lower than the lower end of the hole of the housing hole 30 in the height direction of the metal housing 2. This is to arrange the heat radiation holes 34 at positions as far as possible from the housing hole 30.

[0030] As shown in FIG. 3, the heat radiation holes 34 are provided only at positions facing the first bus bar 27 among the first bus bar 27 and the second bus bar 28. In the case of this example, the heat radiation holes 34 are provided only at positions facing the first bus bar 27 among the first bus bar 27 and the second bus bar 28, but the heat radiation holes 34 may be provided at positions facing each of the first bus bar 27 and the second bus bar 28. Also, the heat radiation holes 34 are not limited to being provided only one for one heat radiation target, and a plurality of them may be provided.

[0031] (Step portion 38 of the heat radiation hole 34) As shown in FIGS. 2 and 4, the heat radiation hole 34 has a step portion 38 that is formed at least in part on the peripheral edge of the hole and is located deeper when viewed from the housing hole 30. The step portion 38 is formed inside the protruding wall 36. As shown in FIG. 4, the step portion 38 is formed over the entire width direction of the inner peripheral surface 39a that is located deeper when viewed from the housing hole 30 among the four inner peripheral surfaces 39a to 39d of the heat radiation hole 34.

[0032] The opening area Sa (see FIG. 2) of the portion of the heat radiation hole 34 that does not include the step portion 38 is preferably set to a size sufficient for the air with heat to flow. In the case of this example, since the step portion 38 is formed inside the heat radiation hole 34, the opening area Sa at the lower part of the heat radiation hole 34 is formed smaller than the opening at the upper part of the heat radiation hole 34. That is, the heat radiation hole 34 has different opening sizes at the upper end and the lower end.

[0033] Next, the operation of the electrical connection box 1 of this embodiment will be described. (Function of the heat radiation hole 34) As shown in FIG. 2, when an electric current flows through the electric circuit of the electrical connection box 1, the relay 13 connected to the electric wire 7 and the bus bar 26 connected to the relay 13 generate heat. The heat generated in the relay 13 and the bus bar 26 accumulates in the space region 35 inside the resin component 14. However, in the case of this example, since the resin component 14 is formed with the heat radiation hole 34 that communicates the space region 35 to the outside, the heat generated in the space region 35 is released to the outside of the space region 35 through the heat radiation hole 34. Therefore, it is possible to improve the heat dissipation performance of the electrical connection box 1. Accordingly, it is possible to suppress the temperature rise of the relay 13 and the bus bar 26.

[0034] Also, in the case of this example, the heat radiation hole 34 is arranged at a position close to the housing hole 30. For this reason, the heat released from the heat radiation hole 34 to the outside of the space region 35 is smoothly discharged to the outside of the metal housing 2 through the housing hole 30 at a position close to the heat radiation hole 34. Therefore, also in this regard, it is possible to satisfy high heat dissipation performance.

[0035] (Design requirements for the heat radiation hole 34) As shown in Fig. 5, when a housing hole 30 is formed in the metal housing 2, for example, even if a foreign object 40 such as a wire enters the inside of the metal housing 2, there is a design requirement for insulation protection so that it does not contact the bus bar 26. The size of the foreign object 40 such as a wire is, for example, a diameter of "1 mm" and a length of "100 mm". In order to satisfy this insulation protection, for example, the heat dissipation hole 34 must be arranged at a position separated from the housing hole 30. However, if this is done, the heat released from the heat dissipation hole 34 cannot be smoothly discharged from the housing hole 30, which hinders ensuring the heat dissipation effect.

[0036] (When there is no step portion 38 in the heat dissipation hole 34) As shown in Fig. 6, when a foreign object 40 such as a wire enters from the housing hole 30, if there is no step portion 38 in the heat dissipation hole 34, the foreign object 40 that has entered the heat dissipation hole 34 may travel along the hole inner surface and cross the heat dissipation hole 34. In this case, the foreign object 40 such as a wire may be exposed from the heat dissipation hole 34 to the space region 35 and may reach the bus bar 26. Therefore, if there is no step portion 38 in the heat dissipation hole 34, the foreign object 40 may contact the bus bar 26, and thus the insulation protection requirement cannot be satisfied.

[0037] (Function of the step portion 38) As shown in Fig. 7, when a foreign object 40 such as a wire enters from the housing hole 30, if there is a step portion 38 in the heat dissipation hole 34, the tip of the foreign object 40 will be caught by the step portion 38 of the heat dissipation hole 34. For this reason, the foreign object 40 cannot proceed deeper from the step portion 38, so the foreign object 40 is prevented from entering the space region 35. Thereby, even if a foreign object 40 such as a wire enters from the housing hole 30, it is possible to make it difficult for this foreign object 40 to reach the bus bar 26. In this way, it is possible to satisfy the design requirement for insulation protection in the electrical connection box 1.

[0038] Also, when providing a stepped portion 38 in the heat dissipation hole 34 to prevent the intrusion of foreign matter 40, it becomes possible to arrange the heat dissipation hole 34 as close as possible to the housing hole 30. As a result, it is also possible to smoothly discharge the heat released from the heat dissipation hole 34 from the housing hole 30. Therefore, it is possible to ensure the heat dissipation property inside the metal housing 2. As described above, it is possible to achieve both ensuring the heat dissipation property inside the metal housing 2 and protecting the bus bar 26 against the intrusion of foreign matter from the housing hole 30.

[0039] (Effects of the Embodiment) According to the configuration of the above embodiment, the following effects can be obtained. (1) The electrical connection box 1 houses a relay unit 8 used for the relay connection of the electric wire 7 inside a metal housing 2. The relay unit 8 includes a resin component 14 that forms the main body of the relay unit 8 and to which at least a relay 13 is attached, and a bus bar 26 that is attached to the resin component 14 and used as wiring in the resin component 14. The metal housing 2 has a housing hole 30 that is attached to the resin component 14 and draws out the electric wire 7 electrically connected to the bus bar 26 to the outside. The resin component 14 has a heat dissipation hole 34 that dissipates the heat of the relay unit 8 generated when the relay unit 8 is energized. The heat dissipation hole 34 has a stepped portion 38 that is located deeper when viewed from the housing hole 30 at least in a part of the hole periphery.

[0040] According to this configuration, since the heat dissipation holes 34 are formed in the resin component 14, it is possible to provide a heat dissipation path inside the metal housing 2. Therefore, the heat generated in the relay unit 8 can be discharged to the outside of the metal housing 2 from the housing hole 30 through the heat dissipation holes 34. Further, even if a foreign object 40 such as a wire that has entered from the housing hole 30 tries to enter the inside of the resin component 14 through the heat dissipation holes 34, the tip of the foreign object 40 can be stopped by the stepped portion 38 of the heat dissipation holes 34. For this reason, the possibility that the foreign object 40 that has entered from the housing hole 30 comes into contact with the bus bar 26 inside the resin component 14 is reduced. As described above, it is possible to achieve both ensuring heat dissipation in the metal housing 2 and protecting the bus bar 26 against foreign object intrusion from the housing hole 30.

[0041] (2) The heat dissipation holes 34 have a circumferential protruding wall 36 on the hole periphery arranged on the surface of the resin component 14. The stepped portion 38 is formed inside the heat dissipation holes 34 having the protruding wall 36. According to this configuration, it is possible to hook and stop a foreign object 40 such as a wire that has entered from the housing hole 30 with the protruding wall 36. Therefore, the intrusion of the foreign object 40 into the heat dissipation holes 34 can be further suppressed.

[0042] (3) The heat dissipation holes 34 are arranged at a position close to the relay 13. According to this configuration, the heat dissipated from the relay 13 can be smoothly circulated from the nearby heat dissipation holes 34. Therefore, it further contributes to ensuring heat dissipation in the metal housing 2.

[0043] (4) The heat dissipation holes 34 are arranged at a position close to the housing hole 30. According to this configuration, the heat of the heat dissipation holes 34 can be smoothly discharged from the housing hole 30 to the outside of the metal housing 2. Therefore, it further contributes to ensuring heat dissipation in the metal housing 2.

[0044] (5) The heat dissipation hole 34 is disposed at a position lower than the lower end of the housing hole 30 in the height direction of the metal housing 2. According to this configuration, it is possible to make the separation distance from the housing hole 30 to the heat dissipation hole 34 as long as possible. Therefore, it is possible to further suppress the intrusion of foreign matter 40 into the heat dissipation hole 34.

[0045] (Other Embodiments) Note that this embodiment can be implemented with the following modifications. This embodiment and the following modification examples can be implemented in combination with each other within a technically non - conflicting range.

[0046] · As shown in FIG. 8, the metal housing 2 may have a discharge hole 42 for discharging the fluid that has flowed into the metal housing 2 from the housing hole 30 to the outside. In this case, since the fluid that has entered the metal housing 2 is discharged from the discharge hole 42 to the outside of the metal housing 2, it is possible to suppress the adhesion of the fluid to electronic components such as the bus bar 26.

[0047] · When the relay 13 and the fuse are mounted on the relay unit 8, the heat dissipation target of the heat dissipation hole 34 is not limited to the relay 13 and may also be the fuse. That is, the heat dissipation hole 34 is not limited to being disposed at a position close to the electric wire 7 connected to the relay 13 and may also be disposed at a position close to the electric wire 7 connected to the fuse.

[0048] · The metal housing 2 is not limited to a two - part configuration and may be composed of one part or three or more parts. · The material of the metal housing 2 is not particularly limited as long as it is metal.

[0049] · In the space region 35 of the resin part 14, heat - generating components other than the bus bar 26 and the fuse may be provided. · The resin part 14 is not limited to a hollow shape having a space region 35 inside, and for example, by omitting the protective cover 16, it may be a simple plate shape.

[0050] · The heat dissipation hole 34 is not limited to being formed in the upper wall of the resin component 14, and may be formed in, for example, the bottom wall or the side wall. · The heat dissipation hole 34 is not limited to dissipating the heat in the space region 35 of the resin component 14 to the outside. For example, when the resin component 14 is in a plate shape, that is, when the resin component 14 has a shape without a space region 35, the heat dissipation hole 34 may be a hole for allowing the heat on the back side of the resin component 14 to escape to the front side.

[0051] · The heat dissipation hole 34 may have a shape in which the protruding wall 36 is omitted. · When a plurality of heat dissipation holes 34 are provided, at least one of them may be formed in a shape different from the others.

[0052] · The hole shape of the heat dissipation hole 34 can adopt various shapes, such as a slit shape, a round hole shape, an elliptical shape, a square shape, a triangular shape, etc. · The stepped portion 38 may have, for example, a shape in which a plurality of protruding pieces are arranged on one side of the hole periphery.

[0053] · The stepped portion 38 may be formed over the entire periphery of the hole. · The stepped portion 38 only needs to have a shape that protrudes toward the housing hole 30 on the inner surface of the heat dissipation hole 34.

[0054] · For example, when the electrical connection box 1 (relay unit 8) is connected to a plurality of electrical components, it may have a function of branching the input and relaying it to each electrical component. · Although the present disclosure has been described based on the embodiments, it should be understood that the present disclosure is not limited to the embodiments and structures. The present disclosure also includes various modifications and modifications within the equivalent scope. In addition, various combinations and forms, and further, other combinations and forms including only one element, more than one element, or less than one element thereof, are also within the scope and thinking scope of the present disclosure.

Description of Reference Numerals

[0055] 1 Electrical connection box 2 Metal housing 3 Housing body 4 Upper Cover 5 Opening 6 Fastening Member 7 Electric Wire 8 Relay Unit 9 First Electric Wire 10 Second Electric Wire 13 Relay 14 Resin Part 15 Resin Part Body 16 Protection Cover 17 Connector 18 Fastening Member 20 Relay Mounting Portion 21 First Connector 22 Second Connector 23 First Connector Mounting Portion 24 Second Connector Mounting Portion 26 Bus Bar 27 First Bus Bar 28 Second Bus Bar 30 Housing Hole 31 First Housing Hole 32 Second Housing Hole 34 Heat Dissipation Hole 35 Space Region 36 Protruding Wall 38 Step Portion 39a Inner Peripheral Surface 39b Inner Peripheral Surface 39c Inner Peripheral Surface 39d Inner Peripheral Surface 40 Foreign Object Ha Distance Sa Opening Area

Claims

1. An electrical connection box in which a relay unit used for relay connection of electric wires is housed inside a metal housing, The relay unit has a resin component that forms the main body of the relay unit and to which at least a relay is attached, and a bus bar that is attached to the resin component and used as wiring in the resin component. The metal housing has a housing hole for drawing out an electric wire of a connector attached to the resin component and electrically connected to the bus bar to the outside. The resin component has a heat dissipation hole for dissipating heat of the relay unit generated when the relay unit is energized. The electrical connection box, wherein the heat dissipation hole has a stepped portion located deeper when viewed from the housing hole at at least a part of the hole periphery.

2. The heat dissipation hole has a circumferential protruding wall at the hole periphery arranged on the surface of the resin component. The electrical connection box according to claim 1, wherein the stepped portion is formed inside the heat dissipation hole having the protruding wall.

3. The electrical connection box according to claim 1, wherein the heat dissipation hole is arranged at a position close to the relay.

4. The electrical connection box according to claim 1, wherein the heat dissipation hole is arranged at a position close to the housing hole.

5. The electrical connection box according to claim 1, wherein the heat dissipation hole is arranged at a position lower than the lower end of the housing hole in the height direction of the metal housing.

Images