Wire harness

Abstract

To provide a wire harness capable of imparting a protection function to an electric wire portion having a flat shape while securing high flexibility.SOLUTION: A wire harness 1 includes: an electric wire portion 2 including an insulated wire and having a flat shape, the cross-section of which has a dimension in a width direction larger than a dimension in a height direction; a pair of exterior materials 3 arranged in contact with each surface 2a on both sides in the height direction of the electric wire portion 2; and a fixed member 4 for fixing the pair of exterior materials 3 with each other in a state of sandwiching the electric wire portion 2 therebetween. The electric wire portion 2 includes one insulated wire configured as a flat wire or includes a plurality of the insulated wires assembled together. The exterior members 3 are formed of a material having a tensile elastic modulus higher than that of an insulated cover, and having bending flexibility higher than that of the electric wire portion in the height direction. The fixed member 4 fixes the pair of exterior materials 3 to each other at a plurality of fixing points provided at intervals along an axial direction of the electric wire portion 2.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a wire harness.

Background Art

[0002] A flat wire formed using a flat conductor is known. By using a flat wire, the space occupied during wiring can be reduced compared to the case of using a general wire having a substantially circular cross-sectional conductor. For example, as a flat wire that achieves both space-saving and flexibility, Patent Documents 1 and 2 filed by the applicants disclose a form in which a wire conductor obtained by forming a stranded wire formed by twisting a plurality of strands into a flat shape is used for an insulated wire.

[0003] Also, conventionally, in general, an exterior material may be used to protect an insulated wire from contact with or collision with an external object. As one type of exterior material, a corrugated tube formed by molding a resin material into a tubular shape having a bellows structure is known. Regarding a flat wire, as shown in FIGS. 3A and 3B, the flat wire 2 may be inserted into a flat corrugated tube 8 to provide protection. A form in which such a flat corrugated tube is used is disclosed in, for example, Patent Document 3.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described above, using a corrugated tube 8 formed into a flat shape as shown in Figures 3A and 3B can add a protective function to the flat wire 2. However, the flat shape of the corrugated tube 8 hinders the bending flexibility of the flat wire 2. In particular, when attempting to bend the assembly of flat wires 2 inserted through the flat corrugated tube 8 in the width direction (edge ​​direction; x direction) of the flat wires, a large force is required for bending. Consequently, when attempting to assemble a wire harness 9 with flat wires 2 inserted through the corrugated tube 8 into a predetermined location such as inside a car, it becomes difficult to easily bend the wires at locations where bending is required along the route. Even if the flat wire 2 is formed to have high flexibility, as disclosed in, for example, Patent Documents 1 and 2, that flexibility cannot be fully utilized in the wiring.

[0006] Therefore, the objective is to provide a wire harness that can provide a protective function to flattened wire sections while ensuring high flexibility. [Means for solving the problem]

[0007] The wire harness of this disclosure includes one or more insulated wires having a conductor and an insulating coating covering the outer circumference of the conductor, and comprises a wire section having a flattened shape with a cross section perpendicular to the axial direction in which the width dimension is greater than the height dimension, a pair of outer covering materials arranged in contact with the two surfaces of the wire section in the height direction, and fixing members that fix the pair of outer covering materials to each other with the wire section sandwiched between them, wherein the wire section includes one of the insulated wires configured as a flattened wire, or includes a group of the insulated wires, the outer covering materials are made of a material with a higher tensile modulus than the insulating coating, and have higher bending flexibility in the height direction than the wire section, and the fixing members fix the pair of outer covering materials to each other at a plurality of fixing points provided at intervals along the axial direction of the wire section. [Effects of the Invention]

[0008] The wire harness described herein is a wire harness that can provide a protective function to flattened wire sections while ensuring high flexibility. [Brief explanation of the drawing]

[0009] [Figure 1] Figures 1A and 1B are a perspective view and a side view, respectively, showing a wire harness according to one embodiment of the present disclosure. [Figure 2] Figure 2 is a cross-sectional view showing a wire harness according to one embodiment of the present disclosure. [Figure 3] Figures 3A and 3B are perspective and side views, respectively, of a conventional wire harness using a flattened corrugated tube. [Figure 4] Figure 4 is a cross-sectional view showing a conventional wire harness using a flattened corrugated tube. [Figure 5] Figure 5 is a perspective view showing an integrated exterior material that constitutes a wire harness in one modified form. [Figure 6] Figure 6 is a side view illustrating the method for evaluating the amount of sagging of electric wires. [Figure 7] Figure 7 is a photograph comparing the amount of sagging between a wire harness using a bellows sheet (H1) and a wire harness using corrugated tubing (H2). [Figure 8] Figures 8A and 8B are graphs comparing the amount of sagging of various samples. Figure 8A shows bending in the height direction, and Figure 8B shows bending in the width direction. [Modes for carrying out the invention]

[0010] [Description of Embodiments in this Disclosure] First, embodiments of this disclosure will be listed and described. The wire harness according to this disclosure includes one or more insulated wires having a conductor and an insulating coating covering the outer circumference of the conductor, and comprises a wire section having a flattened shape with a cross section perpendicular to the axial direction in which the width dimension is greater than the height dimension, a pair of outer covering materials arranged in contact with the two surfaces of the wire section in the height direction, and fixing members that fix the pair of outer covering materials to each other with the wire section sandwiched between them, wherein the wire section includes one of the insulated wires configured as a flattened wire, or includes a group of the insulated wires, the outer covering materials are made of a material with a higher tensile modulus than the insulating coating, and have higher bending flexibility in the height direction than the wire section, and the fixing members fix the pair of outer covering materials to each other at a plurality of fixing points provided at intervals along the axial direction of the wire section.

[0011] The wire harness described above is equipped with an outer sheath that contacts both sides in the height direction of the flattened wire section. Because the outer sheath, which covers a large area of ​​the flattened wire section, is made of a material with a higher tensile modulus than the insulating coating of the wire section, the wire section is effectively protected from contact and collision with external objects. At the same time, the outer sheath exhibits higher bending flexibility than the wire section in the direction corresponding to the height direction, resulting in a highly flexible wire harness. Furthermore, since the fixing members that secure a pair of outer sheath materials to each other are spaced apart along the axial direction, the high flexibility of the outer sheath is not easily compromised even when fixed by the fixing members. As a result, the wire harness exhibits high overall flexibility while maintaining high protective performance, allowing for easy bending at necessary points when routing it inside a vehicle, etc., resulting in high workability during routing.

[0012] Here, it is preferable that the exterior material has greater bending flexibility in the width direction than the wire portion. This makes it particularly easy to increase the bending flexibility of the wire harness in the width direction.

[0013] The pair of exterior materials may each be configured as a sheet material having a bellows structure with concavities and convexities along the axial direction of the wire portion. By providing a bellows structure to the exterior material, even when the constituent material of the exterior material is made of a material having a high tensile elastic modulus and exhibiting high protective performance, it is possible to obtain an exterior material that exhibits high bending flexibility. As a result, excellent bending flexibility can be ensured in the wire harness.

[0014] When the wire harness is supported horizontally, the amount of sag in both the width direction and the height direction is preferably 70% or more of the amount of sag when the wire portion alone is supported horizontally. Then, the bending flexibility of the wire portion is not significantly impaired by the installation of the exterior material, and the wire harness as a whole has excellent bending flexibility in both the width direction and the height direction.

[0015] The fixing member may be composed of a tape having higher flexibility than the exterior material. Then, while maintaining high bending flexibility as a whole, the pair of exterior materials can be stably held in a state of sandwiching the wire portion, and the wire portion can be effectively protected.

[0016] In this case, the fixing member may be wound spirally around the outer periphery of the assembly of the pair of exterior materials and the wire portion, with a gap provided between turns along the axial direction of the wire portion. Then, the mutual fixation of the pair of exterior materials at a plurality of fixing positions provided at intervals can be easily performed.

[0017] The fixing member preferably does not contact the wire portion at positions other than the ends of the exterior material along the axial direction of the wire portion. Then, it becomes difficult for the fixing member to prevent the flexible bending of the wire portion.

[0018] Each of the pair of exterior materials should have a width dimension greater than that of the wire section. This allows the exterior materials to effectively protect both sides of the wire section in the height direction. At the same time, the sides of the wire section in the width direction can also be protected to some extent from contact with external objects. Furthermore, by utilizing the portions of the exterior materials that protrude outward in the width direction from the wire section, mutual fastening between the exterior materials using fixing parts can be easily performed.

[0019] The insulated wire is preferably a flat wire having a flat conductor formed by twisting together multiple strands of wire and shaping it into a flattened form. This results in a wire harness with excellent flexibility, as the conductor has high flexibility in both the height and width directions.

[0020] [Details of the embodiments of this disclosure] Below, an insulated wire and wire harness according to one embodiment of the present disclosure will be described in detail with reference to the drawings. In this specification, with regard to the shape of each part of the wire harness, concepts indicating the shape and arrangement of members, such as straight lines, parallel lines, and perpendicular lines, include errors from geometric concepts within an acceptable range for this type of wire harness, such as deviations of approximately ±15% in length and approximately ±15° in angle. In this specification, unless otherwise specified, the cross-section of the wire harness, wire, or sheathing material refers to a cross-section cut perpendicular to the axial direction (longitudinal direction). Furthermore, various characteristics are values ​​evaluated at room temperature and in the atmosphere.

[0021] <Wire harness overview> Figures 1A, 1B, and 2 show the structure of a wire harness 1 according to one embodiment of the present disclosure. Figure 1A is a perspective view, Figure 1B is a side view, and Figure 2 is a cross-sectional view. The wire harness 1 according to this embodiment has a flat wire 2 as the electric wire portion, a pair of outer covering materials 3, 3, and a tape 4 as a fixing member.

[0022] The wire section included in the wire harness 1 includes one or more insulated wires, each having a conductor 20 and an insulating coating 22 covering the outer circumference of the conductor 20, and the overall cross-section of the wire section perpendicular to the axial direction is flattened. In this embodiment, the wire section is composed of a single insulated wire, which is configured as a flattened wire 2, with an insulating coating 22 formed on the outer circumference of a conductor 20 having a flattened cross-section, and the overall cross-section also being flattened. Here, a flattened shape refers to a shape in which the width dimension in the cross-section is larger than the height dimension perpendicular to the width direction. In the following description and drawings, the width direction in the cross-section of the flattened wire 2 is the x direction, the height direction (up and down direction) is the z direction, and the axial direction (longitudinal direction) perpendicular to the x and z directions is the y direction.

[0023] Each pair of exterior materials 3,3 is constructed as a sheet-like (including plate-like) component. The pair of exterior materials 3,3 are positioned in contact with both sides (upper and lower surfaces 2a, 2a) in the height direction of the flat wire 2 of the wire section. The exterior materials 3,3 are in contact with the upper and lower surfaces 2a, 2a of the wire section over the entire width direction. Preferably, as shown in the illustrated configuration, the width dimension of the exterior materials 3,3 is larger than that of the flat wire 2 of the wire section, and the exterior materials 3,3 extend beyond the flat wire 2 in the width direction.

[0024] The constituent materials and structure of the exterior materials 3,3 will be described in detail later, but they are made of a material having a higher tensile modulus than the insulating coating 22 that constitutes the flat wire 2 of the electric wire section, and have higher bending flexibility than the electric wire section (here, the flat wire 2) in the height direction, and preferably in the width direction as well. The exterior materials 3,3 are not limited to specific materials or structures as long as they satisfy these material properties, but a bellows sheet made of resin material can be given as a preferred configuration for the exterior materials 3,3. The bellows sheet is made of a sheet material having a bellows structure with bellows-like irregularities along the axial direction of the electric wire.

[0025] The fixing member, composed of tape 4, secures a pair of sheathing materials 3, 3 to each other at multiple fixing points spaced apart along the axial direction of the flat electric wire 2. This tape 4 plays a role in stably maintaining the state in which the sheathing materials 3, 3 sandwich the flat electric wire 2 from above and below. In the illustrated configuration, a long, continuous piece of tape 4 is wound spirally around the outer circumference of the assembly of the pair of sheathing materials 3, 3 and the flat electric wire 2, leaving gaps between turns (pitches). The positions where tape 4 is placed in each turn are the fixing points. Because tape 4 is wound with gaps, in areas where tape 4 is not placed, the side portions 2b, 2b (both sides in the width direction) of the flat electric wire 2 are not covered by either the sheathing materials 3, 3 or the tape 4, and are directly exposed to the external environment. In the illustrated configuration, the width dimension of the sheathing materials 3,3 is greater than the width of the flat wire 2, and the tape 4 does not come into contact with the side portions 2b,2b of the flat wire 2. However, at the longitudinal ends of the sheathing materials 3,3, it is preferable to directly fix the sheathing materials 3,3 and the flat wire 2 with the tape 4 so that the flat wire 2 does not shift axially relative to the sheathing materials 3,3 (omitted in Figures 1A and 1B; see Figure 7), and at the fixing portion, the tape 4 may be in direct contact with the surface of the wire, including the side portions 2b,2b. The following describes each component of wire harness 1 in detail.

[0026] <Flat electric wire> The conductor 20 constituting the flat electric wire 2 as the electric wire portion may have a single-wire structure made entirely of a continuous metal material such as metal foil or metal plate, or it may be made as a stranded wire made by twisting together multiple strands 21. However, from the viewpoint of increasing the flexibility of the flat electric wire 2 in both the height and width directions, it is preferable that it be made as a stranded wire. The cross-section of the conductor 20 may be any specific shape as long as it has a flat shape, but in this embodiment, the cross-section of the conductor 20 is approximated as a rectangle. Examples of flat shapes other than rectangles include ellipse, oblong, oval (a shape with semicircles at both ends of a rectangle), parallelogram, trapezoid, etc. When the conductor 20 is made as a stranded wire, the conductor 20 can be formed, for example, by rolling a raw stranded wire made by twisting together multiple strands 21 into a substantially circular cross-section. The flat electric wire 2 is obtained by covering the entire circumference of the conductor 20 with a flat cross-section to form an insulating coating 22.

[0027] Because the flat wire 2 has a conductor 20 with a flat cross-section, it occupies less space in the height direction than conventional round wires with a conductor with a substantially circular cross-section but the same conductor cross-sectional area, thus contributing to space saving. Furthermore, because the conductor 20 has a flat shape and its height is reduced, the insulated wire 1 exhibits high flexibility, especially in the height direction.

[0028] The material constituting the conductor 20 is not particularly limited, and various metallic materials can be applied. Typical metallic materials constituting the conductor 20 include copper and copper alloys, and aluminum and aluminum alloys. In particular, since aluminum and aluminum alloys have lower conductivity than copper and copper alloys, the conductor cross-sectional area tends to be larger in order to ensure the required electrical conductivity. Therefore, flattening the conductor 20 is highly effective in saving space and improving bending flexibility in the height direction. From this viewpoint, it is preferable to construct the conductor 20 from aluminum or an aluminum alloy. Also, from a similar viewpoint, the conductor cross-sectional area should be 10 mm². 2 The above, and furthermore, 50mm 2 Above, 100mm 2The above is preferable. There is no particular upper limit on the conductor cross-sectional area, but from the viewpoint of ensuring bending flexibility, for example, 200 mm 2 The following points should be kept in mind.

[0029] The material constituting the insulating coating 22 is not particularly limited as long as it is an insulating material, but it is preferable that it is based on an organic polymer. In particular, polyvinyl chloride, polyolefins such as polyethylene, fluororesins, and silicone resins can be suitably used due to their high flexibility. Conductor area 10 mm² 2 In the above case, the tensile modulus of the insulating coating 22 composed of these materials will be approximately 200 MPa or less. The insulating coating 22 may contain various additives in addition to the organic polymer, such as flame retardants. The thickness of the insulating coating 22 is not particularly limited, but examples include a range of 1 mm or more and 2 mm or less.

[0030] <Exterior materials> As described above, the outer covering material 3,3 is made of a material having a higher tensile modulus than the insulating coating 22 that constitutes the flat wire 2 of the wire section, and has higher bending flexibility in the height direction than the flat wire 2 (the entire wire section). Furthermore, it is preferable that the outer covering material 3,3 also has higher flexibility in the width direction than the flat wire 2.

[0031] The fact that the constituent materials of the outer covering 3,3 have a higher tensile modulus than the constituent materials of the insulating coating 22 allows the outer covering 3,3 to fully function as a protective material that prevents the flat wire 2 from suffering significant damage due to external physical stimuli. In other words, even if the wire harness 1 comes into contact with or collides with an external object, the outer covering 3,3 absorbs the impact, protecting the flat wire 2 from being subjected to a large impact. The specific tensile modulus of the constituent materials of the outer covering 3,3 is not specified, but a range of 1000 MPa or more and 2000 MPa or less can be preferably exemplified. A tensile modulus of 1500 MPa or more is particularly preferable. The tensile modulus of the resin material can be evaluated by a tensile test in accordance with JIS K 7161.

[0032] From the viewpoint of enhancing the protective performance of the exterior materials 3,3, it is preferable that the constituent materials of the exterior materials 3,3 have a higher tensile modulus than the constituent materials of the insulating coating 22, and also have a higher hardness than the constituent materials of the insulating coating 2. In this specification, the tensile modulus and hardness of a material refer to the physical properties as characteristics of the material species itself, and do not include the effect of the shape, even if the material has a shape other than a simple planar shape, such as a bellows structure of the exterior materials 3,3.

[0033] The protective performance is ensured by the high tensile modulus of elasticity of the exterior materials 3,3, while each exterior material 3 has greater bending flexibility than the flat wire 2, at least in the height direction. As a result, the wire harness 1 as a whole can have high bending flexibility without significantly impairing the flexibility of the flat wire 2. In this specification, the bending flexibility of a member refers to the flexibility obtained when bending the member, including the effect of the shape of the member, such as the bellows structure of the exterior materials 3,3. The exterior materials 3,3, which are made of bellows sheets, exhibit high flexibility in the width direction and the thickness direction (height direction). This is because the exterior materials 3,3 are formed from material into a bellows structure that meanders vertically along the longitudinal direction, and are capable of a certain degree of expansion and contraction. Therefore, when bending the exterior materials 3,3 in the width direction or the thickness direction, the spacing between adjacent peaks widens on the outside of the bend and narrows on the inside of the bend, allowing them to flexibly follow the bend. The bending flexibility of the sheathing material 3,3 and the flat wire 2 can be compared using a three-point bending test, but a simpler method is to compare the amount of sagging when held horizontally (see Figure 6). When comparing one piece of sheathing material 3 and one flat wire 2 cut to the same length, it is desirable that the amount of sagging is greater for the sheathing material 3, at least when the height direction is oriented in the direction of gravity. Furthermore, it is desirable that the amount of sagging is about the same as that of the sheathing material 3 (generally 90% or more) when the width direction is oriented in the direction of gravity.

[0034] The constituent materials of the exterior materials 3,3 are not particularly limited, but resin materials such as polypropylene, polyamide, and polyester can be suitably used because they have a high tensile modulus and exhibit high protective performance. The tensile modulus of exterior materials 3,3 composed of these materials tends to fall within the above range of 1000 MPa or more and 2000 MPa or less. Exterior materials 3,3 may contain various additives such as flame retardants in addition to organic polymers. The thickness (plate thickness) of the sheet material constituting the exterior materials 3,3 is not particularly limited, but a range of 0.2 mm or more and 1 mm or less can be exemplified. Furthermore, a range of 1 mm or more and 3 mm or less can be exemplified for the height of the bellows structure (height between valleys and peaks along the height direction z), and a range of 2 mm or more and 5 mm or less can be exemplified for the pitch of the bellows structure (distance between peaks along the longitudinal direction y). Materials similar to the wall surface of conventional corrugated tubes, as shown in Figures 3A and 3B, can be suitably used as the exterior materials 3,3 of this embodiment, which are formed into a sheet with irregularities arranged in the longitudinal direction.

[0035] <Tape> The type of tape 4 used as a fixing member is not particularly limited, as long as it is made of a long sheet material. However, from the viewpoint of stably maintaining the structure in which the exterior materials 3,3 are fixed, it is preferable to use tape 4 that has an adhesive layer (including a tack layer) on the surface that comes into contact with the exterior materials 3,3.

[0036] To avoid hindering the flexibility of the exterior materials 3,3, it is preferable that the tape 4 has higher flexibility in each direction than the exterior materials 3,3. Furthermore, it is preferable that the tensile modulus of the constituent material of the tape 4 is lower than the tensile modulus of the constituent material of the exterior materials 3,3, and even lower than the tensile modulus of the constituent material of the insulating coating 22. Suitable examples of the constituent material of the tape 4 include a material in which an adhesive layer is provided on one side of a base material made of polyvinyl chloride or the like. The tensile modulus of commercially available tapes made of these materials is generally 50 MPa or less.

[0037] <Protection and flexibility in wire harnesses> In the wire harness 1 according to this embodiment, the outer covering materials 3, 3 are arranged on both sides 2a, 2a in the height direction of the flat wire 2. Therefore, the outer covering materials 3, 3 provide protection to the flat wire 2, and the effects of physical stimuli such as contact and collision applied from the outside are less likely to affect the flat wire 2. High protective performance is obtained because the outer covering materials 3, 3 have a higher tensile modulus than the insulating coating 22 of the flat wire 2.

[0038] Of the surfaces of the flat wire 2 that make up the wire harness 1, the large areas are the upper and lower surfaces 2a, 2a in the height direction. By covering these surfaces 2a, 2a with outer covering materials 3, 3, a high level of protection can be obtained for the flat wire 2. In particular, the protective effect is higher when the outer covering materials 3, 3 have a wider width than the flat wire 2 and cover the upper and lower surfaces 2a, 2a of the flat wire 2 over the entire width direction. The side portions 2b, 2b (surfaces on both sides in the width direction) of the flat wire 2 are not covered by the outer covering material, but because the flat shape of the flat wire 2 reduces the area of ​​the side portions 2b, 2b, the reduction in the overall protective performance of the flat wire 2 due to the side portions 2b, 2b not being covered by the outer covering material is limited. Furthermore, if the outer covering material 3,3 has a greater width than the flat wire 2 and extends beyond the width of the flat wire 2, the extended portion of the outer covering material 3,3 provides a certain degree of protection to the side portions 2b,2b of the flat wire 2 against contact with external objects.

[0039] In the wire harness 1 according to this embodiment, high protective performance is obtained by the outer covering materials 3,3, while the outer covering materials 3,3 are arranged only on the top and bottom of the surface of the flat wire 2 in the height direction, and not on both sides in the width direction, so the wire harness 1 as a whole exhibits high flexibility. As described above, each of the pair of outer covering materials 3,3 has higher flexibility than the flat wire 2 at least in the height direction, and because the outer covering materials 3,3 are arranged to sandwich the flat wire 2 from above and below in the height direction, the wire harness 1 as a whole exhibits high flexibility when bending in the height direction (flat direction) and also when bending in the width direction (edge ​​direction).

[0040] Here, in the case of a wire harness 9 in which a flat wire 2 is inserted through a flat corrugated tube 8, as shown in the perspective and side views in Figures 3A and 3B and the cross-sectional view in Figure 4, high flexibility cannot be obtained when bending in the width direction (x direction) and height direction (z direction) because the constituent material of the corrugated tube 8 surrounds the entire circumference of the flat wire 2. This is because the upper and lower surfaces 81 and 82 of the corrugated tube 8 are integrally connected by side wall surfaces 82 and 82 arranged along the vertical direction, and the corrugated tube 8 has a large second moment of area. In particular, when bending the wire harness 9 in the width direction, it is necessary to deform the side wall surfaces 82 and 82 of the corrugated tube 8 in a plane direction, compressing them on the inside of the bend and extending them on the outside of the bend, so even though a corrugated structure is provided, a large force is required.

[0041] In contrast, in the wire harness 1 according to the embodiment of this disclosure, the upper and lower pair of outer covering materials 3, 3 are configured as separate parts and are arranged with the flat wire 2 in between. As a result, the second moment of area of ​​the outer covering materials 3, 3, even when combined, is smaller than that of the corrugated tube 8 described above. Therefore, the wire harness 1 can be made highly flexible in both the width and height directions.

[0042] In the wire harness 1 according to this embodiment, the tape 4, acting as a fixing member, secures the upper and lower outer covering materials 3, 3 to each other and stably maintains the state in which the flat wire 2 is sandwiched between the outer covering materials 3, 3. The arrangement of this tape 4 also contributes to increasing the flexibility of the wire harness 1. If the tape 4 were wrapped tightly along the axial direction of the flat wire 2, the stability of holding the flat wire 2 would increase, but the overall flexibility of the wire harness would decrease, and the flexibility of the flat wire 2 and the outer covering materials 3, 3 would not be as apparent as the overall flexibility of the wire harness. In contrast, by wrapping the tape 4 with gaps and securing the upper and lower outer covering materials 3, 3 only at fixing points spaced apart along the axial direction of the flat wire 2, high flexibility is maintained for the wire harness 1 as a whole.

[0043] The flexibility of the wire harness 1 can be controlled to some extent by the arrangement of the tape 4. The smaller the gap between turns and the smaller the pitch at which the tape 4 is wrapped, and the tighter the tape 4 is wrapped, the more firmly the upper and lower sheathing materials 3,3 are pressed against and fixed to the flat wire 2, the more stably the state in which the flat wire 2 is sandwiched between the pair of sheathing materials 3,3 is maintained, and the protective performance for the flat wire 2 increases, but the flexibility of the wire harness 1 decreases. On the other hand, the larger the gap between turns and the larger the pitch at which the tape 4 is wrapped, and the looser the tape 4 is wrapped, the less firmly the upper and lower sheathing materials 3,3 are pressed against the flat wire 2, although the protective performance of the sheathing materials 3,3 may decrease, high flexibility can be obtained for the wire harness 1 as a whole. This is because the relative movement of the flat wire 2 is allowed to some extent in the space sandwiched between the pair of sheathing materials 3,3, allowing the flat wire 2 to bend flexibly.

[0044] In the wire harness 1, the size of the gaps between turns when wrapping the tape 4 and the degree of tightness of the wrapping should be selected considering the required protective performance and flexibility. As a suitable configuration that can achieve both sufficient protective performance and flexibility, the size of the gaps between turns of the tape 4 can be exemplified as a range in which the ratio (b / a) of the area covered by the tape 4 to the total area (a) of the outer circumference of the wire harness 1 is 5% or more and 95% or less. Furthermore, as for the tightness of the wrapping of the tape 4, an example can be exemplified as a configuration in which the tape 4 is wrapped with a force such that the outer covering material 3,3 undergoes elastic deformation in the thickness direction due to the contact pressure from the tape 4 (the area where the tape 4 is wrapped is compressed), while the insulating coating 22 is not deformed.

[0045] The overall flexibility of the wire harness 1 can be easily evaluated by measuring the amount of sagging due to its own weight. As shown in Figure 6, one end of the test specimen S (wire harness) is held horizontally by a jig T or the like, and the distance d that the other end hangs from the horizontal position due to its own weight is defined as the amount of sagging. The flexibility in the width direction and height direction can be evaluated by measuring the amount of sagging when the flat shape of the flat wire 2 is positioned in the direction of gravity, respectively. The larger the amount of sagging, the higher the flexibility can be evaluated.

[0046] The flexibility of the wire harness 1 can be evaluated by comparing the amount of sagging of the wire harness 1 with the amount of sagging of flat wires 2 cut to the same length, which is similarly evaluated. For example, it is desirable that the amount of sagging of the wire harness 1 is 60% or more of the amount of sagging of flat wires 2 alone, both in the width and height directions. Furthermore, it is desirable that it be 70% or more. In this case, it can be said that the wire harness 1 as a whole has sufficiently high flexibility. The arrangement of the tape 4 should be set so that this level of sagging is secured in the wire harness 1.

[0047] On the other hand, when wrapping the tape 4, it is possible to reduce the gap between turns to some extent and wrap the tape 4 tightly to maintain the wire harness 1 in a predetermined bent shape. For example, by bending the flat wires 2 and the sheathing materials 3,3 to a predetermined bent shape required by the routing route, and then wrapping the tape 4 around the outer circumference of the assembly of the flat wires 2 and the sheathing materials 3,3, the bent shape can be maintained. If the wire harness 1 is routed to a predetermined location, such as inside a car, while maintaining this bent shape, it becomes unnecessary to apply a large bend to the wire harness 1 again during routing, thus improving work efficiency. In this configuration as well, since the sheathing materials 3,3 are configured as separate upper and lower parts and are fixed to each other by the tape 4, the wire harness 1 exhibits greater flexibility compared to the case where corrugated tubes 8 are used.

[0048] The tape 4 may come into contact with the surface of the flat wire 2 at the side portions 2b, 2b of the flat wire 2. However, from the viewpoint of ensuring the degree of freedom of relative movement of the flat wire 2 in the space between the pair of sheathing materials 3, 3 and increasing the flexibility of the wire harness 1, it is preferable that the tape 4 does not come into contact with the flat wire 2, except at the longitudinal ends of the sheathing materials 3, 3. If the width of the sheathing materials 3, 3 is greater than the width of the flat wire 2, contact between the tape 4 wrapped around the outer circumference of the sheathing materials 3, 3 and the flat wire 2 is less likely to occur.

[0049] <Other forms> In the configuration described above, the wire section is made of a single flat wire 2, the outer covering material 3,3 is made of a pair of bellows sheets, and the fixing member is made of tape 4. However, the components constituting the wire harness of this disclosure are not limited to these. The main modified configurations are briefly described below.

[0050] The wire section may include only one insulated wire configured as a flat wire 2 as described above, or it may include multiple insulated wires bundled together, as long as the overall cross-sectional shape is flat. When multiple insulated wires are included, these insulated wires may be flat wires or conventional round wires with a roughly circular cross-section. In either case, the multiple insulated wires should be arranged along the width direction, and the overall cross-sectional shape of the bundle of multiple insulated wires should be a flat shape that is elongated in the width direction. As long as the cross-section is a flat shape that is elongated in the width direction, the insulated wires may be arranged in multiple layers in the height direction as well as the width direction.

[0051] As a fixing member, the form using tape 4, as described above, is the most superior from the viewpoint of having high flexibility, etc. However, the fixing member is not limited to tape, as long as it can fix a pair of exterior materials 3, 3 to each other at multiple fixing points provided at intervals along the axial direction of the electric wire. For example, the upper and lower exterior materials 3, 3 may be fixed to each other at intervals by bonding or fusing with an adhesive. Alternatively, fixing devices configured as pins, etc., may be arranged at intervals to fix the upper and lower exterior materials 3, 3 to each other.

[0052] As yet another form, the fixing member can be constructed using the same material as the exterior material. In this case, the upper and lower exterior materials and the fixing member may be provided as a single unit. As an example of a form in which the fixing member is provided as a single unit with the exterior material, an integrated exterior material 5 is shown in Figure 5. The integrated exterior material 5 has a pair of upper and lower exterior materials 51, 51 and a fixing member 52 that connects these exterior materials 51, 51. The fixing member 52, like the upper and lower exterior materials 51, 51, is made of a sheet material having a bellows structure, and in the fixing member 52, as with the exterior materials 51, 51, the bellows structure's irregularities are arranged along the longitudinal direction (y direction). Thus, the integrated exterior material 5, in which the exterior materials 51, 51 and the fixing member 52 are integrated, can be easily formed using a flattened corrugated tube 8 similar to the one used in the wire harness 9 in Figures 3A and 3B. In other words, multiple weight-reducing sections W should be formed as window-shaped through holes in the side walls 82, 82 of the corrugated tube 8. The upper and lower surfaces 81, 81 of the corrugated tube 8 function as exterior materials 51, 51, and the side wall surfaces 82, 82 other than the areas where the weight-reducing sections W are formed function as fixing members 52. [Examples]

[0053] Examples are shown below. However, the present invention is not limited to these examples. Here, we compared the flexibility in bending in the height and width directions when using a bellows sheet and when using a corrugated tube as the exterior material.

[0054] (Sample preparation) For the electric wire section, a flattened wire was prepared. A round wire made of stranded aluminum alloy was rolled into a flat shape using rollers to create a flattened conductor, and an insulating coating was formed on the outer circumference of the conductor by extrusion molding. The strands used had an outer diameter of 0.3 mm, and the conductor cross-sectional area was 50 mm². 2 The insulation coating was made of polyvinyl chloride with a thickness of 1 mm. The tensile modulus of the insulating material was 20 MPa. The dimensions of the flat wire after the insulation coating was formed were 19 mm in width and 8 mm in height.

[0055] Two types of exterior materials were prepared: bellows sheets and corrugated tubes. Both exterior materials were made from 1 mm thick polyamide material, with corrugations arranged along the longitudinal direction. The height of the corrugated structure (bellows structure) (height between valleys and peaks along the vertical direction) was 3 mm, and the width of the corrugated structure (distance between peaks along the longitudinal direction) was 4 mm. The tensile modulus of the constituent materials of the exterior material was 1 × 10⁻⁶ 3 The pressure was MPa. The bellows sheet was formed as a long sheet with a width of 30 mm. The corrugated tube was formed as a tubular shape with an outer dimension of 40 mm in width and 18 mm in height, with a flattened cross-section.

[0056] Wire harnesses 1 and 2 were fabricated using these flat wires and sheathing materials. In harness 1, a bellows sheet was used as the sheathing material. The sheathing material was brought into contact with both sides of a single flat wire in the height direction, and tape was wrapped around the outer circumference of the assembly to fix the sheathing materials together, thereby fabricating a wire harness with the structure shown in Figures 1A, 1B, and 2. As the tape, a polyvinyl chloride sheet with an adhesive layer on one side was used, and it was wrapped so that the gap between turns (distance along the axis direction of the flat wire) was 30 mm.

[0057] Meanwhile, for harness 2, a wire harness with the structure shown in Figures 3A, 3B, and 4 was fabricated by inserting flat wires through a corrugated tube. In both harnesses 1 and 2, the length of the flat wires was 600 mm in the axial direction, and the length of the sheathing material was 500 mm, with 50 mm of flat wire protruding from both ends of the sheathing material in the axial direction. Furthermore, the sheathing material was secured to the flat wires using tape at both ends. In harness 1, the tape was designed so that it did not come into contact with the flat wires except at the fixing points at the ends.

[0058] (Test method) The amount of sagging due to self-weight was evaluated for each of the harnesses 1 and 2 described above, as well as the flat wires, bellows sheets, and corrugated tubes that constitute these wire harnesses. For the evaluation, as shown in Figure 6, one end of each test specimen S was held horizontally, and the distance d that the other end hung from the horizontal position due to its own weight was measured as the amount of sagging and compared between the samples. The test was performed in two ways: with the height direction (thickness direction; flat direction) oriented in the direction of gravity, and with the width direction (edge ​​direction) oriented. For harnesses 1 and 2, the dimensions described above for sample preparation were used, and for the bellows sheets and corrugated tubes, 500 mm lengths were cut and used individually. For the flat wires, both 500 mm lengths were used for comparison with the bellows sheets and corrugated tubes, and 600 mm lengths were used for comparison with harnesses 1 and 2. For harnesses 1 and 2, the amount of sagging was measured in the area where the bellows sheet was placed, as shown in Figure 7 for harness 2 (H2).

[0059] (Test results) Figure 7 shows a photograph of the test being conducted to measure the amount of sag, comparing harness 1 and harness 2. Here, the height direction of the flat wire is oriented in the direction of gravity, and the bending flexibility in the height direction is compared. As shown in the photograph, harness 1 (H1), which uses a bellows sheet, has a significantly larger amount of sag than harness 2 (H2), which uses a corrugated tube. In other words, harness 1 has significantly higher flexibility.

[0060] Furthermore, Figures 8A and 8B show the results of evaluating the amount of sagging for harnesses 1 and 2, flat wires of two different lengths (abbreviated as "wires" in the figures), and two types of exterior materials. Figure 8A shows the amount of sagging in the height direction, and Figure 8B shows the amount of sagging in the width direction.

[0061] In Figures 8A and 8B, comparing the sag of a 500mm flat wire and a corrugated sheet, the corrugated sheet sags more in the height direction. In the width direction, the sag of both is about the same. In other words, it can be confirmed that the corrugated sheet has significantly higher bending flexibility than the flat wire, at least in the height direction. Considering that the flat wire has a greater mass than the corrugated sheet, the difference in bending flexibility, excluding the effect of its own weight, is greater than the difference in sag. In the width direction as well, the difference in sag between the corrugated sheet and the flat wire is very small, and considering that the flat wire has a greater mass, it can be said that the corrugated sheet has higher flexibility.

[0062] Next, comparing the amount of sag between harness 1, which uses a bellows sheet, and harness 2, which uses a corrugated tube, in Figures 8A and 8B, harness 1 has a greater amount of sag than harness 2 in both the height and width directions. In other words, harness 1 exhibits higher bending flexibility in both the height and width directions. Harness 1 has a mass of 160g, and harness 2 has a mass of 175g, with harness 2 having a larger mass. Therefore, even excluding the effect of its own weight, harness 1 can be said to have higher bending flexibility in both the height and width directions than harness 2.

[0063] Comparing the amount of sag between harness 1, which is constructed using a bellows sheet, and a single flat wire, the amount of sag of harness 1 is approximately 90% in the height direction and approximately 70% in the width direction compared to the amount of sag of the flat wire (600 mm). Harness 1 has a greater mass than the flat wire due to the bellows sheet and tape, so the amount of sag cannot be simply converted into a difference in bending flexibility. However, generally speaking, if the amount of sag of the wire harness is 70% or more of the amount of sag of the flat wire, it can be said that the bending flexibility of the flat wire is maintained at a sufficiently high level even when it is made into a wire harness using a bellows sheet and tape.

[0064] Based on the above test results, it was confirmed that by using a bellows sheet, which has higher bending flexibility than flat wires, as the outer covering material, and by sandwiching the upper and lower surfaces of the flat wire in the height direction with this covering material and securing it with tape to form a wire harness, higher flexibility can be obtained in both the height and width directions compared to when using corrugated tubing.

[0065] Although embodiments of the present disclosure have been described in detail above, the present invention is not limited in any way to the above embodiments, and various modifications are possible without departing from the spirit of the present invention. [Explanation of Symbols]

[0066] 1 Wire harness 2 Flat wire (wire section) 2a Upper and lower surfaces 2b Side part 20 Conductors 21 strands 22 Insulating coating 3. Exterior material (accordion sheet) 4. Tape (fixing material) 5 Integrated exterior material 51 Exterior materials 52 Fixing member 8 corrugated tubing 81 Upper and lower surfaces 82 Side wall 9. Conventional wire harness H1 Harness 1 H2 Harness 2 S Test Specimen T-shaped jig W (Weight reduction section) x width direction y-axis direction z-direction (height)

Claims

1. an electric wire portion including one or more insulated electric wires each having a conductor and an insulating coating covering the outer periphery of the conductor, the electric wire portion having a flat shape in a cross section perpendicular to the axial direction in which the dimension in the width direction is greater than the dimension in the height direction; a pair of exterior materials arranged in contact with both sides of the electric wire portion in the height direction; a fixing member that fixes the pair of exterior materials to each other with the electric wire portion sandwiched therebetween, The electric wire portion includes one insulated electric wire configured as a flat electric wire or a collection of a plurality of the insulated electric wires, the sheath material is made of a material having a higher tensile modulus than the insulating coating and has higher bending flexibility in the height direction than the electric wire portion, The fixing member fixes the pair of exterior materials to each other at a plurality of fixing points provided at intervals along the axial direction of the electric wire portion.

2. The wire harness according to claim 1 , wherein the exterior material has higher bending flexibility in the width direction than the electric wire portion.

3. 3. The wire harness according to claim 1, wherein each of the pair of exterior materials is configured as a sheet material having a bellows structure with projections and depressions along an axial direction of the electric wire portion.

4. 4. The wire harness according to claim 1, wherein a sagging amount when the wire harness is supported in a horizontal direction is 70% or more of a sagging amount when the electric wire portion alone is supported in the horizontal direction in both the width direction and the height direction.

5. The wire harness according to claim 1 , wherein the fixing member is made of a tape having higher flexibility than the exterior material.

6. 6. The wire harness according to claim 5, wherein the fixing member is wound around an outer periphery of the assembly of the pair of exterior materials and the electric wire portion in a spiral shape with gaps provided between turns along an axial direction of the electric wire portion.

7. 7. The wire harness according to claim 1, wherein the fixing member is not in contact with the electric wire portion at a position other than an end of the exterior material along an axial direction of the electric wire portion.

8. The wire harness according to claim 1 , wherein each of the pair of exterior materials has a dimension in the width direction larger than that of the electric wire portion.

9. 9. The wire harness according to claim 1, wherein the insulated wire is a flat wire having, as the conductor, a flat conductor obtained by twisting together a plurality of wires and shaping the twisted wire into a flat shape.

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