JP2012244746A - Heat radiation structure of wiring harness - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent heat accumulation of an air layer in a sheath material and suppress the temperature rise of electric wires forming a wiring harness when the wiring harness composed of the multiple electric wires is inserted into the sheath material.SOLUTION: Annular protruding parts 13, continuing in the circumferential direction, are provided on an inner peripheral surface of a cylindrical sheath material for a wiring harness 12, which is formed by rubber or elastomer, so as to be spaced away from each other in the axial direction, and multiple electric wires 11 forming the wiring harness 10 are inserted into the sheath material for the wiring harness 12 contacting with the protruding parts 13.

Description

  TECHNICAL FIELD The present invention relates to a heat dissipation structure for a wire harness, and more particularly, when a wire harness composed of a plurality of electric wires is inserted into an exterior material, the heat of an air layer in the exterior material is prevented to form a wire harness. It suppresses temperature rise.

  Conventionally, in order to protect a wire harness composed of a plurality of electric wires arranged in an automobile from an external interference material or the like, for example, in JP-A-9-107615 (Patent Document 1), a resin tube as shown in FIG. The wire harness 1 is inserted through the outer packaging material 2. Also, in Japanese Patent Application Laid-Open No. 2003-348736 (Patent Document 2), a grommet formed in an accordion shape with an elastic member such as rubber as an exterior material 3 for inserting and protecting a wire harness that is bent or twisted (FIG. 5). Is used.

  On the other hand, in a wire harness routed between a motor and an inverter of an electric vehicle or a hybrid vehicle, between a battery and an inverter, etc., since the energization current is large, the heat generation amount of the electric wire is increased, and the wire harness shown in FIG. When inserted through the exterior materials 2 and 3 as shown in FIG. 5, heat is generated in the air layer formed in the exterior materials 2 and 3, and the temperature around the wires also rises, so that the wire temperature rises significantly. There is a problem. The above problem can be dealt with by using a wire with a high heat-resistant temperature or using a wire with a large wire diameter, but using a wire with a high heat-resistant temperature increases the cost. If a large electric wire is used, it leads to an increase in weight and requires a large wiring space, which may cause layout problems.

JP-A-9-107615 JP 2003-348736 A

  An object of the present invention is to prevent a heat rise of an air layer in an exterior material and suppress a temperature rise of the electrical wire constituting the wire harness when a wire harness composed of a plurality of wires is inserted into the exterior material. Yes.

In order to solve the above-mentioned problems, the present invention provides an annular ridge that is continuous in the circumferential direction on the inner peripheral surface of a tubular wire harness exterior member formed of rubber or elastomer with an interval in the axial direction. Provided,
Provided is a heat dissipation structure for a wire harness, wherein a plurality of electric wires constituting the wire harness are inserted into the wire harness exterior member in a state of being in contact with the protruding portion.

  As described above, in the present invention, the annular ridges continuous in the circumferential direction are spaced apart in the axial direction on the inner peripheral surface of a wire harness exterior material (hereinafter referred to as an exterior material) formed of rubber or elastomer. And a plurality of wires of a wire harness that are inserted through the exterior material are brought into contact with the protruding portion. The material forming the exterior material is rubber or elastomer, and the material has a higher thermal conductivity than air. Therefore, by contacting each wire inserted into the exterior material with the annular ridge formed of the material, The generated heat moves to the ridge rather than the air layer in the exterior material, and is efficiently radiated to the outside of the exterior material through the ridge. Therefore, even when the energization current of the electric wire is large, heat dissipation of the air layer in the exterior material can be suppressed to improve heat dissipation, and a significant temperature increase of the electric wire can be prevented. Therefore, it is not necessary to use an electric wire with a high heat-resistant temperature or an electric wire with a large electric wire diameter as in the prior art, and it is possible to realize cost reduction, weight reduction, and space saving. In addition, in this invention, the case where the electric wire which penetrates an exterior material is made to contact a rib part includes the case where the electric wire which covered the metal braided wire etc. which are shielding means is made to contact a rib part.

In addition, although the ridges that come into contact with each electric wire may be partially cured by heat, curing of the entire exterior material can be prevented by providing the ridges at intervals in the axial direction of the exterior material. Therefore, moderate elasticity and strength as an exterior material can be maintained.
An annular protrusion provided at an interval on the inner peripheral surface of the exterior material has a predetermined width in the axial direction and a constant thickness, and each inserted wire and the protruding section are surfaces along the axial direction. Alternatively, it is preferable to allow line contact.
The dimensions of the ridges and the dimensions between the ridges adjacent to each other in the axial direction cannot be limited because they differ depending on the inserted electric wires and exterior materials. The above-mentioned dimensions may be appropriately set so that the resin is not cured and good heat dissipation is obtained in a balanced manner over the entire length in the axial direction.

  The wire harness exterior material is preferably formed of ethylene propylene diene rubber (EPDM). The ethylene propylene diene rubber (EPDM) has elasticity and strength suitable for an exterior material, and the thermal conductivity of air is 0.0241 W / m · k, whereas the thermal conductivity of EPDM is 0.00. Since the thermal conductivity of 356 W / m · k is relatively high, the heat dissipation of the air layer in the exterior material can be effectively suppressed to further improve the heat dissipation. However, it is not limited to the ethylene propylene diene rubber (EPDM). For example, silicone rubber, acrylonitrile butadiene rubber (NBR), fluorine rubber (FKM), chloroprene rubber (CR), acrylic rubber (ACM), natural rubber It can also be formed by (NR) or the like.

  The plurality of electric wires are preferably electric wires that connect between a motor and an inverter of an electric vehicle or a hybrid vehicle or between a battery and an inverter.

  A plurality of electric wires connecting between a motor and an inverter of an electric vehicle or a hybrid vehicle or between a battery and an inverter have a large energizing current and a large amount of heat generation. Therefore, by adopting the heat dissipating structure of the present invention for the electric wire group, it is possible to suppress the heat of the air layer in the exterior material to improve the heat dissipating property and to prevent the temperature of each electric wire from rising significantly.

  Moreover, it is preferable that the uneven | corrugated | grooved part is provided in the outer peripheral surface of the said exterior material in which the said protrusion part is provided in the inner peripheral surface.

  As described above, it is possible to increase the surface area on the outer peripheral surface side that comes into contact with the outside air by providing an uneven portion on the outer peripheral surface of the exterior material on which the ridge portion is provided, and the heat transferred to the ridge portion. Can be discharged to the outside air more efficiently. It is preferable that the concavo-convex portions are provided continuously in the circumferential direction.

  As described above, in the present invention, a wire that is provided on the inner peripheral surface of an exterior material made of rubber or elastomer with an annular ridge portion continuous in the circumferential direction at an interval in the axial direction, and is inserted through the exterior material. It is set as the structure which makes the several electric wire of a harness contact the said protrusion part. That is, by bringing each electric wire inserted into the outer packaging material into contact with an annular ridge made of rubber or elastomer having a thermal conductivity larger than that of air, the heat generated in the electric wire is rather than the air layer in the outer packaging material. It moves to the said ridge part side, and it thermally radiates efficiently to the exterior of an exterior material through this ridge part. Therefore, even when the energization current of the electric wire is large, heat dissipation of the air layer in the exterior material can be suppressed to improve heat dissipation, and a significant temperature increase of the electric wire can be prevented. Therefore, it is not necessary to use an electric wire with a high heat-resistant temperature or an electric wire with a large electric wire diameter, and it is possible to realize cost reduction, weight reduction, and space saving.

The heat dissipation structure of the wire harness of 1st Embodiment is shown, (A) is sectional drawing of the axial direction of the exterior material which penetrated the wire harness, (B) is the sectional view on the AA line of (A). It is a principal part expanded sectional view of an exterior material. It is sectional drawing of the axial direction of the exterior material which penetrated the wire harness in 2nd Embodiment. It is a figure which shows a prior art example. It is a figure which shows a prior art example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 show a first embodiment of the present invention. In the present embodiment, the core wire 11a (11a-A, 11a-B, 11a-C) is connected to the insulating coating material 11b (11b-A, 11b-B) between the motor of the electric vehicle and the inverter (not shown). 11b-C) is inserted through the wire harness 10 comprising the three electric wires 11 (11A, 11B, 11C) covered with the wire harness exterior material 12 (hereinafter referred to as the exterior material 12) shown in FIGS. It is routed.

  The exterior material 12 has a substantially cylindrical shape formed of ethylene propylene diene rubber (EPDM), and a plurality of annular ridges 13 continuous in the circumferential direction are provided on the inner peripheral surface of the exterior wall of the exterior material 12 at intervals. The inner diameter r1 of the protrusion 13 is smaller than the inner diameter r2 of the peripheral wall where the protrusion 13 is not provided. Each of the protrusions 13 has a predetermined width w in the axial direction and a constant thickness t, and the three electric wires 11A, 11B, 11C inserted through the exterior member 12 and the protrusions 13 Line contact is made along the axial direction at the contact positions 14A, 14B, and 14C. Each dimension (width w, thickness t) of the ridge 13 and a dimension L between the ridges 13 arranged adjacent to each other in the axial direction are exterior materials due to heat received by the ridge 13 from the electric wires 11A, 11B, and 11C. 12 can be appropriately set so that the whole 12 is not cured and good heat dissipation is obtained in a balanced manner over the entire length in the axial direction.

In the present embodiment, the outer diameter r3 of the exterior member 12 through which the wire harness 10 composed of three electric wires 11A, 11B, and 11C (electric wire diameter 5.3 mm) connecting the motor and the inverter of the electric vehicle is 22 mm. When the inner diameter r2 of the peripheral wall not provided with the ridge 13 is 19 mm, the thickness t of the annular ridge 13 is about 2 mm, the width w in the axial direction is about 20 mm, and the dimension between the adjacent ridges 13. L is about 20 mm.
Moreover, the cyclic | annular uneven | corrugated | grooved part 15 continued in the circumferential direction is provided in the outer peripheral surface of the exterior material 12 surrounding wall which provided the protruding part 13 in the inner peripheral surface.

  As described above, in the present embodiment, on the inner peripheral surface of the exterior member 12 formed of ethylene propylene diene rubber (EPDM), the annular ridges 13 that are continuous in the circumferential direction are provided at intervals in the axial direction. The three electric wires 11A, 11B, and 11C of the wire harness 10 inserted through the exterior material 12 are brought into contact with the ridge 13. The heat generated in the electric wires 11A, 11B, and 11C is caused by bringing the electric wires 11A, 11B, and 11C inserted through the exterior material 12 into contact with the annular protrusion 13 made of EPDM having a thermal conductivity larger than that of air. It moves to the ridge 13 side rather than the air layer 16 in the exterior material 12, and efficiently radiates heat to the outside of the exterior material 12 through the ridge 13. Therefore, as in this embodiment, even when the energization current of the electric wires 11A, 11B, and 11C is large, the heat dissipation of the air layer 16 in the exterior material 12 is suppressed and heat dissipation is improved, and the electric wires 11A, 11B, and 11C are greatly reduced. Temperature rise can be prevented. Therefore, it is not necessary to use an electric wire with a high heat-resistant temperature or an electric wire with a large electric wire diameter, and it is possible to realize cost reduction, weight reduction, and space saving. In addition, as described above, the outer surface of the outer peripheral surface that comes into contact with the outside air is provided by providing the annular concavo-convex portion 15 that is continuous in the circumferential direction on the outer peripheral surface of the outer peripheral wall of the exterior material 12 provided with the protrusion 13 on the inner peripheral surface. Since the heat that has moved to the ridge 13 can be released to the outside air more efficiently, the heat dissipation can be further improved.

FIG. 3 shows a second embodiment.
In the second embodiment, as shown in FIG. 3, the exterior material 22 has a bellows shape in which annular ridges 20 and valleys 21 that are continuous in the circumferential direction are alternately provided in the axial direction, and the bellows-like exterior. On the inner peripheral surface of the material 22, protrusions 23 are provided at intervals. Other points are the same as in the first embodiment.

Also in the second embodiment, heat dissipation of the air layer in the exterior material 22 can be suppressed to improve heat dissipation, and a significant temperature rise of the wires 11A, 11B, and 11C can be prevented, and the exterior material 22 can be bellows. Therefore, the flexibility and heat dissipation can be further improved.
In the first and second embodiments, the electric wires 11A, 11B, and 11C are brought into direct contact with the ridges 13 and 23. However, the electric wire with the metal braided wire that is a shielding means covered on the outer peripheral surface is the ridge. 13 and 23 may be brought into contact with each other. Further, the number of wires to be inserted is not limited to 3, and may be 2 or 4 or more.

10 Wire harness 11 (11A, 11B, 11C) Electric wire 11a (11a-A, 11a-B, 11a-C) Core wire 11b (11b-A, 11b-B, 11b-C) Insulation coating material 12, 22 For wire harness Exterior materials 13 and 23 Projection portions 14A, 14B and 14C Contact position 15 Concavity and convexity portion 16 Air layer r1 Inner diameter r2 of projection portion Inner diameter r3 of outer wall where no projection portion is provided Outer diameter of exterior material t Thickness of projection portion W Width of ridge L Dimension between adjacent ridges

Claims (3)

On the inner peripheral surface of the tubular wire harness exterior material formed of rubber or elastomer, annular ridges continuous in the circumferential direction are provided with an interval in the axial direction,
A heat dissipation structure for a wire harness, wherein a plurality of electric wires constituting the wire harness are inserted through the wire harness exterior member in a state of being in contact with the protrusions.   The heat dissipation structure for a wire harness according to claim 1, wherein the plurality of electric wires are electric wires that connect between a motor and an inverter of an electric vehicle or a hybrid vehicle, or between a battery and an inverter.   The heat dissipation structure for a wire harness according to claim 1 or 2, wherein a concavo-convex portion is provided on an outer peripheral surface of the exterior material for a wire harness in which the protruding portion is formed on an inner peripheral surface.

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