Harness heat dissipation structure

Abstract

This harness heat dissipation structure (1) comprises: a wire harness (3) that is routed in a vehicle body (115) of a vehicle (100); and a pressing member (5) that presses the wire harness (3) against the vehicle body (115). The wire harness (3) has a conductive plate-shaped conductor (10), and the plate-shaped conductor (10) has a rectangular cross-section in a direction orthogonal to the routing direction of the wire harness (3). The vehicle body (115) has a thick portion (117), which is formed thicker than the surrounding portions, at the location where the pressing member (5) is attached and the plate-shaped conductor (10) of the wire harness (3) is pressed by the pressing member (5).

Description

Harness heat dissipation structure

[0001] The present invention relates to a harness heat dissipation structure.

[0002] Patent Document 1 discloses technology related to a wire harness used in vehicles such as electric vehicles and plug-in hybrid vehicles, which includes electric wires that electrically connect a high-voltage battery to an electrical device such as an inverter. The wire harness includes multiple electric wires, a pair of connectors attached to both ends of the electric wires, multiple exterior members through which the multiple electric wires are inserted one by one, and multiple clamps. Each exterior member protects the electric wires from, for example, flying objects or water droplets. The multiple exterior members are fixed to the vehicle body or the like by clamps. With this configuration, heat generated in the electric wires can be transferred to the vehicle body, which has a large surface area, through the exterior members and the clamps.

[0003] Japanese Patent Application Laid-Open No. 2020-21556

[0004] In vehicles, as vehicles become more electrified, larger currents flow through wire harnesses, and as this current increases, measures are needed to prevent Joule heat, particularly in the plate conductors (bus bars) of the wire harness.When a wire harness is fixed to a vehicle body for the purpose of heat dissipation, the vehicle body is generally made of iron or steel plate, which has a relatively small thermal capacity, and heat dissipation by thermal conduction from the plate conductors of the wire harness to the vehicle body may not be sufficient.

[0005] The present invention has been made in view of the problems inherent in the conventional art, and an object of the present invention is to provide a harness heat dissipation structure that can efficiently dissipate heat generated in the plate-like conductor of a wire harness.

[0006] A harness heat dissipation structure according to an embodiment of the present invention includes a wire harness arranged in a vehicle body and a pressing member that presses the wire harness against the vehicle body, wherein the wire harness has a conductive plate-shaped conductor that has a rectangular cross-sectional shape in a direction perpendicular to the wiring direction of the wire harness, and the vehicle body has a thick portion that is thicker than the surrounding area at a location where the pressing member is attached and where the plate-shaped conductor of the wire harness is pressed by the pressing member.

[0007] According to the present invention, it is possible to provide a harness heat dissipation structure that can efficiently dissipate heat generated in the plate-like conductor of the wire harness.

[0008] Fig. 1 is a diagram showing a schematic configuration of high-voltage wiring of an electric vehicle to which this embodiment is applied. Fig. 2 is a schematic perspective view showing an example of a harness heat dissipation structure according to this embodiment. Fig. 3 is a schematic cross-sectional view showing an example of a harness heat dissipation structure according to this embodiment. Fig. 4 is a schematic cross-sectional view showing a harness heat dissipation structure according to another embodiment. Fig. 5 is a schematic cross-sectional view showing a harness heat dissipation structure according to another embodiment. Fig. 6 is a schematic cross-sectional view showing a harness heat dissipation structure according to another embodiment.

[0009] The harness heat dissipation structure according to the present embodiment will be described in detail below with reference to the drawings. Note that the dimensional proportions in the drawings are exaggerated for the sake of convenience and may differ from the actual proportions.

[0010] The harness heat dissipation structure 1 according to this embodiment can be applied to high-voltage wiring of an electric vehicle as shown in FIG.

[0011] As shown in Fig. 1, a vehicle 100 has an inverter 101 and a motor 103 disposed as loads, for example, on the front side in the longitudinal direction of the vehicle. The inverter 101 is electrically connected to a high-voltage battery 107 via a front high-voltage wiring 105, and converts DC power supplied from the high-voltage battery 107 via the front high-voltage wiring 105 into AC power. The inverter 101 also supplies the converted AC power to the motor 103. The motor 103 is driven by the power supplied from the inverter 101, and rotates front wheels 109 via a drive shaft or the like of the vehicle 100.

[0012] A charging port 111 is also disposed on the vehicle 100, for example, at the rear side in the vehicle longitudinal direction. The charging port 111 has a charging inlet to which an external charging device (not shown) serving as a charger is connected. The charging port 111 is electrically connected to the high-voltage battery 107 via a rear high-voltage wiring 113, and supplies power from the external charging device via the rear high-voltage wiring 113 to the high-voltage battery 107.

[0013] As shown in FIGS. 2 and 3 , the harness heat dissipation structure 1 according to this embodiment includes a wire harness 3 and a pressing member 5 .

[0014] The wire harness 3 is routed in a body panel 115 (see FIG. 1 ) that constitutes a part of the body of the vehicle 100. The wire harness 3 has a bus bar 10 as a conductive plate-shaped conductor, and the bus bar 10 is made of a metal material such as copper or aluminum. The wire harness 3 has a plurality of bus bars 10 (two in this embodiment), but is not limited thereto, and the wire harness 3 may have a single bus bar 10 (one).

[0015] The busbar 10 has a rectangular cross section in a direction perpendicular to the wiring direction of the wire harness 3. The busbar 10 has a pair of long side surfaces 11 and a pair of short side surfaces 13, and is formed to have a rectangular cross section.

[0016] In this embodiment, the busbar 10 is disposed lying on its side so that the pair of long side surfaces 11 are parallel to the upper surface of the body panel 115. Therefore, the upper surface of the busbar 10 (one of the pair of long side surfaces 11) faces an upper surface 21 of the pressing member 5, which will be described later, and the lower surface of the busbar 10 (the other of the pair of long side surfaces 11) faces a thick portion 117 of the body panel 115, which will be described later.

[0017] The pressing member 5 is used to press the wire harness 3 against the body panel 115. The pressing member 5 may be made of a synthetic resin material or a metal material. In this embodiment, the pressing member 5 has an upper surface portion 21 extending in a direction intersecting the routing direction of the wire harness 3, and a pair of side surfaces 23, 23 extending from both ends of the upper surface portion 21 in the extending direction toward the thick portion 117 of the body panel 115. The pressing member 5 further has a pair of flanges 25, 25 extending in directions away from each other from the lower end of the side surface portion 23 and coupled to the thick portion 117 using a coupling member such as a bolt 7, and is formed into a hat-shaped cross section.

[0018] Furthermore, a partition wall portion 27 extending toward the thick portion 117 of the body panel 115 is formed at a location between the plurality of bus bars 10 on the upper surface portion 21 of the pressing member 5 .

[0019] The bus bar 10 pressed against the body panel 115 is disposed in a space surrounded by the upper surface 21 of the pressing member 5 , the pair of side surfaces 23 , 23 , and the thick portion 117 of the body panel 115 .

[0020] Furthermore, a heat dissipation sheet 30 serving as a heat dissipation member having thermal conductivity is disposed between the bus bar 10 and the thick portion 117 of the body panel 115 in order to efficiently transfer heat generated in the bus bar 10 to the thick portion 117 of the body panel 115. This heat dissipation sheet 30 is also referred to as a thermal conduction sheet, and is disposed in close contact with the bus bar 10 and the thick portion 117 of the body panel 115.

[0021] The wire harness 3 and the pressing member 5 are disposed on the interior side of the body panel 115 (above the floor).

[0022] The body panel 115 has a thick portion 117 formed thicker than the surrounding portion at a location where the pressing member 5 is attached and where the bus bar 10 of the wire harness 3 is pressed by the pressing member 5. A general portion 119 that is thinner than the thick portion 117 is formed around the thick portion 117 in the body panel 115. The thick portion 117 is formed so as to protrude into the vehicle interior of the body panel 115. A metal plate that constitutes part of the thick portion 117 may be attached to the body panel 115 made of an iron plate or a steel plate by welding or the like. When the body panel 115 is produced by casting, the thick portion 117 may be molded integrally with the body panel 115 during casting. That is, the thick portion 117 may be formed integrally with the body panel 115, or may be formed separately from the body panel 115 and attached to the body panel 115.

[0023] As described above, the harness heat dissipation structure 1 according to this embodiment includes the wire harness 3 arranged in the vehicle body (body panel 115) of the vehicle 100, and the pressing member 5 that presses the wire harness 3 against the vehicle body (body panel 115). The wire harness 3 has a conductive plate-shaped conductor (bus bar 10), and the plate-shaped conductor (bus bar 10) has a rectangular cross section in a direction perpendicular to the wiring direction of the wire harness 3. The vehicle body (body panel 115) has a thick portion 117 that is thicker than the surrounding area at a location where the pressing member 5 is attached and where the pressing member 5 presses the plate-shaped conductor (bus bar 10) of the wire harness 3.

[0024] By using the pressing member 5 to press the bus bar 10 against the body panel 115, Joule heat generated in the bus bar 10 can be transferred to the body panel 115 and dissipated, thereby suppressing a temperature rise in the wire harness 3. This makes it possible to avoid increasing the size of the components (particularly the bus bar 10) that constitute the wire harness 3 in order to suppress heat generation in the wire harness 3, thereby enabling reductions in the weight and manufacturing cost of the wire harness 3.

[0025] Furthermore, by forming the thick portion 117 at the portion of the body panel 115 against which the bus bar 10 is pressed by the pressing member 5, it is possible to increase the heat capacity of the body panel 115 and suppress or delay the temperature rise time of the wire harness 3. This makes it possible to avoid increasing the size of the components (particularly the bus bar 10) that constitute the wire harness 3 in order to suppress heat generation in the wire harness 3, thereby making it possible to reduce the weight of the wire harness 3 and the manufacturing cost.

[0026] As described above, according to this embodiment, it is possible to provide the harness heat dissipation structure 1 that can efficiently dissipate heat generated in the plate-shaped conductor (bus bar 10) of the wire harness 3.

[0027] In the harness heat dissipation structure 1, a heat dissipation member (heat dissipation sheet 30) having thermal conductivity may be arranged between the plate-shaped conductor (bus bar 10) and the thick portion 117 of the vehicle body (body panel 115).

[0028] By disposing the heat dissipation sheet 30 on the portion of the bus bar 10 that contacts the body panel 115, the gap between the bus bar 10 and the body panel 115 can be filled, allowing heat to be efficiently transferred from the bus bar 10 to the body panel 115.

[0029] In the harness heat dissipation structure 1, the pressing member 5 may have an upper surface portion 21 extending in a direction intersecting the routing direction of the wire harness 3, and a pair of side surfaces 23, 23 extending from both ends of the upper surface portion 21 in the extending direction toward a thick portion 117 of the vehicle body (body panel 115). The pressing member 5 may further have a pair of flanges 25, 25 extending in directions away from each other from the lower end of the side surface portion 23 and coupled to the thick portion 117, and may be formed with a hat-shaped cross section. The plate-shaped conductor (bus bar 10) pressed against the vehicle body (body panel 115) may be disposed in a space surrounded by the upper surface portion 21, the pair of side surfaces 23, 23 of the pressing member 5, and the thick portion 117 of the vehicle body (body panel 115).

[0030] By pressing the bus bar 10 against the body panel 115 using a pressing member 5 formed with a hat-shaped cross section, the heat generated in the bus bar 10 can be sufficiently transferred to the body panel 115, thereby improving the heat dissipation performance of the harness heat dissipation structure 1.

[0031] 4 to 6, harness heat dissipation structures 1A, 1B, and 1C according to other embodiments will be described below. Note that components that are substantially the same as those in the harness heat dissipation structure 1 described above will be assigned the same reference numerals, and descriptions thereof will be omitted.

[0032] As shown in FIG. 4 , in the harness heat dissipation structure 1A, a plurality of heat dissipation fins 121 are formed on the outer side of the vehicle cabin (underfloor side) of the body panel 115 where the thick-walled portion 117 is formed. The attachment direction and shape of the heat dissipation fins 121 can be appropriately determined so that air heated by heat conduction from the bus bar 10 does not stagnate between the plurality of heat dissipation fins 121. The metal material constituting the heat dissipation fins 121 may be attached to the body panel 115 made of an iron or steel plate by welding or the like. If the body panel 115 is produced by casting, the heat dissipation fins 121 may be molded integrally with the body panel 115 during casting. That is, the heat dissipation fins 121 may be formed integrally with the body panel 115, or may be formed separately from the body panel 115 and attached to the body panel 115.

[0033] In this way, in the harness heat dissipation structure 1A, the wire harness 3 and the pressing member 5 may be disposed on the passenger compartment side (above the floor) of the vehicle body (body panel 115). The heat dissipation fin 121 may be formed on the passenger compartment side (under the floor) of the vehicle body (body panel 115) at a location where the thick-walled portion 117 is formed.

[0034] By forming heat dissipation fins 121 on the back side of the mounting surface of the bus bar 10 on the body panel 115 and increasing the area (surface area) of the body panel 115 that comes into contact with the outside air, it is possible to further improve the heat dissipation performance of the harness heat dissipation structure 1.

[0035] 5 , in the harness heat dissipation structure 1B, the bus bar 10 is arranged upright so as to be perpendicular to the body panel 115. Therefore, the upper surface of the bus bar 10 (one of the pair of short side surfaces 13, 13) faces the upper surface 21 of the pressing member 5, which will be described later, and the lower surface of the bus bar 10 (the other of the pair of short side surfaces 13, 13) faces the thick portion 117 of the body panel 115.

[0036] In this way, in the harness heat dissipation structure 1B, the plate-shaped conductor (bus bar 10) may be arranged upright so as to be perpendicular to the vehicle body (body panel 115).

[0037] Depending on the installation requirements for the wire harness 3 on the vehicle 100, the bus bar 10 may be installed with its longitudinal direction standing as shown in FIG. 5 . Even in this case, the heat generated in the bus bar 10 can be efficiently transferred to the thick portion 117 of the body panel 115.

[0038] 6 , in the harness heat dissipation structure 1C, a rib portion 123 serving as a wall portion standing perpendicular to the body panel 115 is formed on the thick portion 117 of the body panel 115, and the bus bar 10 is pressed against the rib portion 123 by a spring member 31. Therefore, one side surface of the bus bar 10 (one of the pair of long side surfaces 11) faces the rib portion 123 of the body panel 115, and the other side surface of the bus bar 10 (the other of the pair of long side surfaces 11) faces the spring member 31. In addition, heat-conducting members 40 are disposed between the bus bar 10 and the thick portion 117 of the body panel 115, and between the bus bar 10 and the rib portion 123 of the body panel 115, respectively. The heat conduction member 40 is intended to efficiently conduct heat generated in the bus bar 10 to the thick portion 117 and the rib portion 123 of the body panel 115, and is made of, for example, thermal paste or thermally conductive resin. The harness heat dissipation structure 1C also uses a case 41 with an L-shaped cross section, whose main purpose is to hold the bus bar 10 when the pressing member 5 is attached to the body panel 115. The case 41 is made of, for example, a synthetic resin material.

[0039] In this manner, in the harness heat dissipation structure 1C, a wall portion (rib portion 123) that stands perpendicular to the vehicle body (body panel 115) may be formed on the thick portion 117 of the vehicle body (body panel 115). The plate-shaped conductor (bus bar 10) may be pressed against the wall portion (rib portion 123) by the spring member 31.

[0040] When the busbar 10 is mounted with its longitudinal direction standing as shown in Fig. 5, only the short side surface 13 of the busbar 10 faces the thick portion 117, and it is predicted that the heat dissipation effect will be smaller than when the long side surface 11 of the busbar 10 faces the thick portion 117. For this reason, as shown in Fig. 6, by forming a rib portion 123 on the thick portion 117 of the body panel 115 and pressing the busbar 10 against this rib portion 123 using a spring member 31, it is possible to improve the heat dissipation effect.

[0041] The entire contents of Japanese Patent Application No. 2023-213079 (filing date: December 18, 2023) are incorporated herein by reference.

[0042] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

[0043] REFERENCE SIGNS LIST 1 harness heat dissipation structure 3 wire harness 5 pressing member 10 bus bar 21 upper surface portion 23 side surface portion 25 flange portion 30 heat dissipation sheet 31 spring member 40 heat conduction member 100 vehicle 115 body panel 117 thick portion 121 heat dissipation fin 123 rib portion

Claims

1. A harness heat dissipation structure comprising: a wire harness arranged in a vehicle body; and a pressing member for pressing the wire harness against the vehicle body, wherein the wire harness has a conductive plate-shaped conductor, the plate-shaped conductor having a rectangular cross-sectional shape in a direction perpendicular to a wiring direction of the wire harness, and the vehicle body has a thick portion at a location where the pressing member is attached and where the plate-shaped conductor of the wire harness is pressed by the pressing member, the thick portion being formed to be thicker than surrounding portions.

2. The harness heat dissipation structure according to claim 1, wherein a heat dissipation member having thermal conductivity is disposed between the plate-like conductor and the thick portion of the vehicle body.

3. A harness heat dissipation structure as claimed in claim 1 or 2, wherein the wire harness and the pressing member are arranged on the inside of the passenger compartment of the vehicle body, and a heat dissipation fin is formed on the outside of the passenger compartment at a location on the vehicle body where the thick-walled portion is formed.

4. A harness heat dissipation structure as claimed in any one of claims 1 to 3, wherein the plate-shaped conductor is arranged to be upright so as to be perpendicular to the vehicle body.

5. A harness heat dissipation structure as set forth in claim 4, wherein a wall portion is formed in the thick portion of the vehicle body and is erected perpendicular to the vehicle body, and the plate-shaped conductor is pressed against the wall portion by a spring member.

6. A harness heat dissipation structure as claimed in any one of claims 1 to 5, wherein the pressing member is formed in a hat-shaped cross section having an upper surface portion extending in a direction intersecting the wiring direction of the wire harness, a pair of side portions extending from both ends of the upper surface portion in the extending direction towards the thick portion of the vehicle body, and a pair of flange portions extending from lower ends of the side portions in directions away from each other and joined to the thick portion, and the plate-shaped conductor pressed against the vehicle body is positioned in a space surrounded by the upper surface portion of the pressing member, the pair of side portions, and the thick portion of the vehicle body.

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