Harness heat dissipation structure

Abstract

A 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) includes an electric wire (10) having a conductive conductor core wire (11) and a covering insulator (13) that covers the conductor core wire (11). The electric wire (10) has a flat portion (15) having a flattened cross-sectional surface in a direction orthogonal to the routing direction of the wire harness (3). The vehicle body (115) has a thick wall portion (117), which is formed thicker than the peripheral portion thereof, at a location to which the pressing member (5) is attached, and against which the flat portion (15) of the electric wire (10) in 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] 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 wires 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 wires 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 electric wires 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 includes electric wires having conductive conductor cores and insulating coverings that cover the conductor cores, the electric wires having flat portions that have a flat cross-sectional shape in a direction perpendicular to the wiring direction of the wire harness, and the vehicle body has thick portions that are thicker than surrounding portions at locations where the pressing member is attached and where the flat portions of the electric wires in the wire harness are 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 electric wires 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 perspective view showing an example of an electric wire of a wire harness. Fig. 5 is a cross-sectional view taken along line A-A in Fig. 4. Fig. 6 is a cross-sectional view taken along line B-B in Fig. 4. Fig. 7 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 includes an electric wire 10 having a conductive conductor core wire 11 and an insulating coating 13 that covers the conductor core wire 11, and the conductor core wire 11 of the electric wire 10 is made of a metal material such as copper or aluminum. The wire harness 3 has a plurality of electric wires 10 (two in this embodiment), but is not limited thereto, and the wire harness 3 may have a single electric wire 10.

[0015] 4 to 6 , the electric wire 10 has a flat portion 15 having a flat cross section in a direction perpendicular to the wiring direction of the wire harness 3. In the present embodiment, the portion of the electric wire 10 other than the flat portion 15 is formed as a circular portion 17 having a circular cross section in a direction perpendicular to the wiring direction of the wire harness 3. That is, in the present embodiment, the flat portion 15 is partially formed by flattening a portion of the wire harness 3 that is pressed against a thick portion 117 of a body panel 115 (described later). However, the present invention is not limited to this, and the flat portion 15 may be formed entirely on the wire harness 3, for example, as in a flat cable.

[0016] 2 and 3 , in this embodiment, the electric wire 10 is disposed so that its upper and lower surfaces are substantially parallel to the upper surface of the body panel 115. Therefore, the upper surface of the electric wire 10 faces an upper surface portion 21 of the pressing member 5, which will be described later, and the lower surface of the electric wire 10 faces a thick portion 117 of the body panel 115.

[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] The flat portion 15 of the electric wire 10 pressed against the body panel 115 is arranged 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 .

[0019] A thermally conductive member 40 is disposed around the flat portion 15 of the electric wire 10 to fill the periphery of the flat portion 15 and efficiently transfer heat generated in the flat portion 15 to the thick portion 117 of the body panel 115. The thermally conductive member 40 is formed of, for example, thermal paste or thermally conductive resin.

[0020] Further, a metal plate 41 is arranged on the pressing member 5 to accommodate and hold the flat portion 15 of the electric wire 10 covered with the heat conducting member 40 in the aforementioned space in the pressing member 5 .

[0021] Furthermore, a heat dissipation sheet 30 serving as a heat dissipation member having thermal conductivity is disposed between the flat portion 15 of the electric wire 10 and the thick portion 117 of the body panel 115 in order to efficiently transfer heat generated in the flat portion 15 of the electric wire 10 to the thick portion 117 of the body panel 115. This heat dissipation sheet 30 is also called a thermal conduction sheet, and is disposed in close contact with the metal plate 41 and the thick portion 117 of the body panel 115.

[0022] The wire harness 3 and the pressing member 5 are disposed on the interior side of the body panel 115 (above the floor).

[0023] 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 pressing member 5 presses against the flat portion 15 of the electric wires 10 in the wire harness 3. 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 passenger compartment of the body panel 115. A metal plate that constitutes a part of the thick portion 117 may be attached by welding or the like to the body panel 115 made of an iron plate or steel plate. 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.

[0024] As described above, the harness heat dissipation structure 1 according to this embodiment includes the wire harness 3 arranged in the 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 includes an electric wire 10 having a conductive conductor core wire 11 and a covering insulator 13 that covers the conductor core wire 11, and the electric wire 10 has a flat portion 15 that has a flat cross-sectional shape 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 flat portion 15 of the electric wire 10 in the wire harness 3 is pressed by the pressing member 5.

[0025] By using the pressing member 5 to press the electric wire 10 against the body panel 115, Joule heat generated in the electric wire 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 conductor core wires 11) that constitute the wire harness 3 in order to suppress heat generation in the wire harness 3, thereby enabling reduction in the weight of the wire harness 3 and reduction in manufacturing costs.

[0026] The electric wire 10 has a flat portion 15, and by pressing the flat portion 15 against the body panel 115 using the pressing member 5, the surface area in contact with the body panel 115 can be increased compared to a typical electric wire having a circular cross section. By pressing the flat portion 15 against the body panel 115 using the pressing member 5, heat generated in the electric wire 10 can be sufficiently transferred to the body panel 115, and a temperature rise in the wire harness 3 can be suppressed.

[0027] Furthermore, by forming the thick portion 117 at the portion of the body panel 115 where the electric wire 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. Therefore, it is possible to avoid increasing the size of the components (particularly the conductor core wires 11) that constitute the wire harness 3 in order to suppress heat generation in the wire harness 3, and it is possible to reduce the weight of the wire harness 3 and the manufacturing cost.

[0028] As described above, according to this embodiment, it is possible to provide the harness heat dissipation structure 1 that can efficiently dissipate the heat generated in the electric wires 10 of the wire harness 3 .

[0029] In the harness heat dissipation structure 1, a heat dissipation member (heat dissipation sheet 30) having thermal conductivity may be arranged between the flat portion 15 of the electric wire 10 and the thick portion 117 of the vehicle body (body panel 115).

[0030] By placing the heat dissipation sheet 30 on the part of the electric wire 10 facing the body panel 115, the gap between the electric wire 10 and the body panel 115 can be filled, and heat can be efficiently transferred from the electric wire 10 to the body panel 115.

[0031] In the harness heat dissipation structure 1 , a heat-conducting member 40 having thermal conductivity may be arranged on the outer periphery of the flat portion 15 of the electric wire 10 .

[0032] By filling the area around the flat portion 15 of the electric wire 10 with the heat conducting member 40, heat can be efficiently conducted from the electric wire 10 to the body panel 115.

[0033] 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 flat portion 15 of the electric wire 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).

[0034] By pressing the electric wire 10 against the body panel 115 using a pressing member 5 formed with a hat-shaped cross section, the heat generated in the electric wire 10 can be sufficiently transferred to the body panel 115, thereby improving the heat dissipation performance of the harness heat dissipation structure 1.

[0035] Another embodiment of the harness heat dissipation structure 1A according to another embodiment will be described below with reference to Fig. 7. Components that are substantially the same as those in the harness heat dissipation structure 1 described above are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0036] As shown in FIG. 7 , in the harness heat dissipation structure 1A, a plurality of heat dissipation fins 121 are formed on the outer side (underfloor side) of the vehicle cabin at a location where the thick-walled portion 117 is formed in the body panel 115. The attachment direction and shape of the heat dissipation fins 121 can be appropriately determined so that air heated by heat conduction from the electric wires 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.

[0037] 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.

[0038] By forming heat dissipation fins 121 on the back side of the mounting surface of the body panel 115 to which the electric wire 10 is attached, 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.

[0039] The entire contents of Japanese Patent Application No. 2023-213084 (filing date: December 18, 2023) are incorporated herein by reference.

[0040] 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.

[0041] REFERENCE SIGNS LIST 1 Harness heat dissipation structure 3 Wire harness 5 Pressing member 10 Electric wire 11 Conductor core wire 13 Covering insulator 15 Flat portion 21 Top surface portion 23 Side surface portion 25 Flange portion 30 Heat dissipation sheet 40 Heat conducting member 100 Vehicle 115 Body panel 117 Thick portion 121 Heat dissipation fin

Claims

1. A harness heat dissipation structure comprising: a wire harness arranged in a vehicle body; and a pressing member pressing the wire harness against the vehicle body, wherein the wire harness includes electric wires having conductive conductor cores and insulating coverings the conductor cores, the electric wires having a flat portion whose cross section in a direction perpendicular to a wiring direction of the wire harness is flattened, and the vehicle body has a thick portion formed to be thicker than surrounding portions at a location where the pressing member is attached and where the flat portion of the electric wire in the wire harness is pressed by the pressing member.

2. The harness heat dissipation structure according to claim 1, wherein a heat dissipation member having thermal conductivity is disposed between the flat portion of the electric wire 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 according to any one of claims 1 to 3, wherein a heat-conducting member having thermal conductivity is arranged on the outer periphery of the flat portion of the electric wire.

5. A harness heat dissipation structure as claimed in any one of claims 1 to 4, 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 in directions away from each other from the lower ends of the side portions and joined to the thick portion, and the flat portion of the electric wire 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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