Wire harness manufacturing method

Abstract

This invention provides a wire harness manufacturing method that allows for the simpler production of flat wire harnesses. [Solution] The method for manufacturing a wire harness WH comprises: a first step of bundling a plurality of electric wires W with a sheet material 10 to form a bundle member; a second step of pressing the bundle member formed in the first step from the outside in the radial direction of the plurality of electric wires W to move the plurality of electric wires W within the sheet material 10 so that the plurality of electric wires W are arranged in a flat shape; and a third step of further pressing the bundle member from the outside from the state in which the plurality of electric wires W have been moved in the second step to be arranged in a flat shape to break the sheet material 10, thereby sandwiching the plurality of electric wires W arranged in a flat shape between the sheet material 10.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a wire harness.

Background Art

[0002] Conventionally, a wire harness has been proposed that is formed in a flat shape by adhering a sheet material such as a non-woven fabric and an electric wire (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, for the wire harnesses described in Patent Documents 1 and 2, it is necessary to arrange the electric wires with respect to the sheet material and then sandwich them with another sheet material or the like, which is laborious in terms of aligning the electric wires on the sheet material.

[0005] The present invention has been made to solve such conventional problems, and an object thereof is to provide a method for manufacturing a wire harness that can more easily manufacture a flat wire harness.

Means for Solving the Problems

[0006] The method for manufacturing a wire harness according to the present invention comprises: a first step of bundling a plurality of electric wires with a sheet material to form a bundle member; a second step of pressing the bundle member formed in the first step from the outside in the radial direction of the plurality of electric wires to move the plurality of electric wires within the sheet material so that the plurality of electric wires are arranged in a flat shape; and a third step of further pressing the bundle member from the outside from the state in which the plurality of electric wires have been moved in the second step to be arranged in a flat shape to break the sheet material, thereby sandwiching the plurality of electric wires arranged in a flat shape between the sheet material. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a method for manufacturing wire harnesses that allows for the simpler production of flat-shaped wire harnesses. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view showing a wire harness manufactured by the wire harness manufacturing method according to this embodiment. [Figure 2] Figure 1 shows a detailed cross-sectional view of the sheet material, where (a) shows an example of a single-layer structure, (b) shows an example of a two-layer structure, and (c) shows an example of a three-layer structure. [Figure 3] This is a process diagram showing the first step of the manufacturing method of the wire harness according to this embodiment, where (a) is a top view and (b) is a cross-sectional view. [Figure 4] This is a process diagram showing the second step of the method for manufacturing a wire harness according to this embodiment. [Figure 5] This is a process diagram showing the third step of the method for manufacturing a wire harness according to this embodiment. [Figure 6] This is a process diagram showing the fourth step of the method for manufacturing a wire harness according to this embodiment. [Figure 7] This is a diagram showing examples and comparative examples. [Figure 8] This is a cross-sectional view showing an example of a case where an adhesive layer is partially provided on a sheet material. [Modes for carrying out the invention]

[0009] The present invention will be described below in accordance with preferred embodiments. It should be noted that the present invention is not limited to the embodiments shown below, and can be modified as appropriate without departing from the spirit of the invention. Furthermore, in the embodiments shown below, some illustrations and descriptions of certain components are omitted. It goes without saying that, regarding the details of the omitted technologies, publicly known or well-known technologies are applied as appropriate, to the extent that they do not contradict the content described below.

[0010] Figure 1 is a cross-sectional view showing a wire harness manufactured by the wire harness manufacturing method according to this embodiment. The wire harness WH shown in Figure 1 is installed, for example, on the wall surface WA of a vehicle, and consists of multiple electric wires W arranged in a flat shape and bundled together. Such a wire harness WH comprises multiple electric wires W and a sheet material 10.

[0011] Multiple wires W are arranged in a flat shape, that is, along the wall surface WA in the example shown in Figure 1. Multiple wires W may be power lines, signal lines, or a combination of both. Note that while the wires W are assumed to be of any size and made of PVC (Polyvinyl Chloride) or polyolefin, they are not limited to these and may also be twisted wires, coaxial cables, or optical fibers.

[0012] The sheet material 10 is used to bundle multiple electric wires W into a flat shape. The sheet material 10 has a structure that sandwiches the multiple electric wires W from above and below (in the direction perpendicular to the flat plane). In this embodiment, due to its manufacturing method, the same sheet material 10 is used for both the top and bottom.

[0013] Also, various materials can be used for the sheet material 10, but in this embodiment, a one-layer to three-layer structure is adopted. FIG. 2 is a cross-sectional view showing the details of the sheet material 10 shown in FIG. 1. (a) shows an example of a one-layer structure, (b) shows an example of a two-layer structure, and (c) shows an example of a three-layer structure.

[0014] As shown in FIG. 2(a), the one-layer structure sheet material 10 is composed of a synthetic resin base material layer 10a. Specifically, the base material layer 10a is composed of a film such as PVC, olefin (polypropylene or polyethylene), fluorine, polyethylene terephthalate, polyimide, silicone, cellophane, nylon, etc. Note that the one-layer structure sheet material 10 may be composed of a cloth material. Such a base material layer 10a is preferably, for example, 0.03 mm or more and 0.45 mm or less in thickness.

[0015] Furthermore, the one-layer structure sheet material 10 may be composed only of an adhesive layer. The adhesive layer is composed of, for example, a material containing at least one of natural rubber, synthetic rubber, and acrylic resin.

[0016] Also, as shown in FIG. 2(b), the two-layer structure sheet material 10 is composed of a base material layer 10a and an adhesive layer 10b. The base material layer 10a is the same as the above-mentioned one, and the adhesive layer 10b is also the same as the above-mentioned one. Also, a cloth material may be adopted for the base material layer 10a. Here, as shown in FIG. 1, the sheet material 10 needs to bundle the electric wires W in a flat shape. Since the two-layer structure sheet material 10 has an adhesive layer 10b, for example, it is not necessary to thermally weld the ends 11 of the opposing sheet materials 10 shown in FIG. 1 to bundle the electric wires W, and a plurality of electric wires W can be fixed. Such an adhesive layer 10b is preferably, for example, 0.005 mm or more in thickness.

[0017] Also, as shown in Fig. 2(c), the three-layered sheet material 10 includes an undercoat layer 10c between two-layered ones. Since this sheet material 10 includes an adhesive layer 10b as described above, there is no need for heat welding or the like, and a plurality of electric wires W can be fixed. Further, since this sheet material 10 includes an undercoat layer 10c, it is possible to prevent the substances in the adhesive layer 10b from migrating to the base material layer 10a and becoming difficult to exhibit adhesive force, or the base material layer 10a from deteriorating. Also, since the sheet material 10 includes an undercoat layer 10c, sufficient adhesion can be obtained even when the compatibility between the base material layer 10a and the adhesive layer 10b is poor.

[0018] Next, a method for manufacturing the wire harness WH according to the present embodiment will be described. Figs. 3 to 6 are process diagrams showing the method for manufacturing the wire harness WH according to the present embodiment. Fig. 3 shows the first step, Fig. 4 shows the second step, Fig. 5 shows the third step, and Fig. 6 shows the fourth step. Note that Fig. 3(a) shows a top view, and Fig. 3(b) shows a cross-sectional view.

[0019] First, as shown in Figs. 3(a) and 3(b), in the first step, an operator wraps the sheet material 10 around a specific portion in the longitudinal direction of a plurality of electric wires W. Thereby, the operator forms a bundle member FM in which the plurality of electric wires W are gathered into a circular or elliptical shape.

[0020] Here, assuming that the bundle member FM gathers the plurality of electric wires W into a circular shape, when not considering the overlapping portion of the sheet material 10, the length of the sheet material 10 in the cross section is 2πr. Here, r is the radius in the cross section of the bundle member FM. The length of the sheet material 10 is preferably not less than twice and not more than four times the total of the diameters of all the electric wires W to be bundled. This is because it becomes a length suitable for subsequent breakage and bundling of the sheet material 10. of all the electric wires W to be bundled. This is because it becomes a length suitable for subsequent breakage and bundling of the sheet material 10.

[0021] Here, the sheet material 10 wrapped in the first step is to have an overall elongation of 150% or less and a tensile strength of 18 N / 19 mm or less. Alternatively, the sheet material 10 may have an overall elongation of 38% or less and a tensile strength of 26 N / 19 mm or less. Furthermore, the elongation and tensile strength may be partially achieved by making cuts in the sheet material 10, etc. However, since these partial areas will become fracture points as described later, care must be taken when wrapping the sheet material 10 around multiple electric wires W and when compressing it as described later.

[0022] Next, as shown in Figure 4, in the second step, the worker uses a specific tool to press the bundle member FM from the outside in the radial direction of the multiple electric wires W. This causes the worker to move the multiple electric wires W within the sheet material 10 so that they are arranged in a flat shape.

[0023] Here, if in the first step the bundle member FM bundles multiple electric wires W into a circular shape, then in the second step the bundle member FM becomes, for example, elliptical. In this state, if the overlapping portion of the sheet material 10 is not considered, the length of the sheet material 10 in cross-section is π [3(a+b)-{(a+3b)(3a+b)} 1 / 2 〕(>2πr). Here, a is the major axis in the cross-section of the bundle member FM, and b is the minor axis in the cross-section of the bundle member FM, and is a value that is limited by the above-mentioned r.

[0024] Subsequently, as shown in Figure 5, in the third step, the worker further presses the bundle member FM using a specific tool. As a result, the sheet material 10 breaks, for example, at both ends of the flat shape (the ends perpendicular to the pressing direction in a cross-sectional view). The break may occur at one end. This results in a wire harness WH in which multiple electric wires W are arranged in a flat shape and sandwiched from above and below. If the sheet material 10 does not have an adhesive layer 10b, the ends 11 of the sheet material 10 are heat-welded or ultrasonically welded at this stage. However, as shown in Figure 5, there are cases where the electric wires W are located near the ends 11, making welding difficult. For this reason, it is preferable that the sheet material 10 used has an adhesive layer 10b. Also, as described above, if the sheet material 10 has the above elongation or tensile strength in a partial area, it is preferable to wrap or press the sheet material 10 so that the partial area becomes the flat end.

[0025] Next, as shown in Figure 6, in the fourth step, the worker may provide a protective base material 20 as needed. In this case, the protective base material 20 is provided at a position adjacent to the sheet material 10 in the longitudinal direction. In particular, by providing an adhesive layer on the protective base material 20, it is possible to fix it at any point and increase the tensile strength of the wire harness WH in the longitudinal direction.

[0026] Next, examples and comparative examples will be described. Figure 7 is a diagram showing examples and comparative examples. As shown in Figure 7, in the examples and comparative examples, a sheet material with a two-layer structure consisting of a base layer and an adhesive layer is used.

[0027] Furthermore, in Examples 1 and 2, cellophane (Nichiban product code 405) was used as the base layer, while in Example 3 and Comparative Examples 1-3, PVC (Yazaki VTA070) was used as the base layer. In addition, nonwoven fabric (fabric material: TESA 50608) was used in Examples 4 and 5 and Comparative Examples 4 and 5.

[0028] Furthermore, in Examples 1, 3, and 4 and Comparative Examples 1 to 4, the adhesive layer was provided over the entire surface (entire area) of the sheet material, while in Examples 2 and 5 and Comparative Example 5, the adhesive layer was provided only partially on the sheet material.

[0029] Figure 8 is a cross-sectional view showing an example of a case where an adhesive layer is partially provided on a sheet material. As shown in Figure 8, when the sheet material is bundled, the adhesive layer is removed at an angle of 40° on the side perpendicular to the pressing direction, leaving the other adhesive layers intact.

[0030] Refer to Figure 7 again. The thickness of the substrate layer was 0.04 mm in Examples 1 and 2, and 0.07 mm in Example 3 and Comparative Examples 1-3. The thickness of the substrate layer was 0.1 mm in Examples 4 and 5, and 0.3 mm in Comparative Examples 4 and 5.

[0031] Furthermore, the thickness of the adhesive layer was 0.005 mm in Examples 1 and 2, 0.01 mm in Comparative Example 1, and 0.02 mm in Example 3. In addition, the thickness of the adhesive layer was 0.05 mm in Comparative Example 2, 0.07 mm in Comparative Example 3, and 0.04 mm in Examples 4 and 5 and Comparative Examples 4 and 5.

[0032] Furthermore, the elongation of the sheet material was set to 50% in Examples 1 and 2, 150% in Example 3 and Comparative Example 1, 155% in Comparative Example 2, and 160% in Comparative Example 3. In addition, the elongation of the sheet material was set to 33% in Example 4, 38% in Example 5, and 25% in Comparative Examples 4 and 5.

[0033] Furthermore, the tensile strength of the sheet material was set to 7 N / 19 mm in Examples 1 and 2, 18 N / 19 mm in Example 3 and Comparative Example 1, and 19 N / 19 mm in Comparative Examples 2 and 3. In addition, the tensile strength of the sheet material was set to 20 N / 19 mm in Example 4, 26 N / 19 mm in Example 5, 45 N / 19 mm in Comparative Example 4, and 47 N / 19 mm in Comparative Example 5.

[0034] Wire harnesses were fabricated in the same manner as described above using the sheet materials of Examples 1-5 and Comparative Examples 1-5. Seven CIVUS wires with a conductor cross-sectional area of ​​0.13 sq were used for the wires. The sheet material was 0.6 cm long and 1 cm wide. The pressure applied to the bundle members was varied between 0.001 MPa and 0.09 MPa, but the results remained unchanged, as described later.

[0035] The applicant then evaluated wire harnesses made using the sheet materials of Examples 1-5 and Comparative Examples 1-5 for bundling, substrate breakage, and wire damage. Bundling was evaluated based on whether the sheet material and the wire moved relative to each other (i.e., whether they stuck together) after being pressed with a maximum pressure of 0.09 MPa. Those that did not move relative to each other were evaluated as "○", and those that moved relative to each other were evaluated as "×". Substrate breakage was evaluated based on whether the sheet material broke when the bundle member was pressed with a maximum pressure of 0.09 MPa. Those that broke the sheet material were evaluated as "○", and those that did not break were evaluated as "×". Wire damage was evaluated based on whether the insulation of the wire deformed and the minimum wall thickness could be guaranteed after being pressed with a maximum pressure of 0.09 MPa. Those that were able to guarantee the minimum wall thickness were evaluated as "○", and those that were not able to guarantee the minimum wall thickness were evaluated as "×".

[0036] As a result, all of Examples 1 to 5 showed "○" for bundling, substrate breakage, and wire damage. In contrast, Comparative Example 1 showed "×" for bundling. Therefore, it was found that while a thickness of 0.005 mm of adhesive layer may be sufficient in some cases to fix the wires, 0.02 mm or more is preferable. Furthermore, Comparative Example 3 showed "×" for substrate breakage, and Comparative Examples 2 to 5 showed "×" for wire damage. Therefore, it was found that in order to appropriately break the sheet material without damaging the wires, it is preferable for the sheet material to have an elongation of 150% or less and a tensile strength of 18 N / 19 mm or less, or an elongation of 38% or less and a tensile strength of 26 N / 19 mm or less.

[0037] In this way, the manufacturing method of the wire harness WH according to this embodiment involves bundling a plurality of electric wires W with a sheet material 10 to form a bundle member FM, pressing from the outside to arrange the plurality of electric wires W in a flat shape, and simultaneously breaking the sheet material 10. As a result, the work of aligning the electric wires on the sheet material is not required, and the process can be completed with the simple operation of simply bundling them. Therefore, a flat wire harness WH can be manufactured more easily.

[0038] Furthermore, the bundle member FM is formed using a sheet material 10 having an overall or partial elongation of 150% or less and a tensile strength of 18 N / 19 mm or less, or a sheet material 10 having an elongation of 38% or less and a tensile strength of 26 N / 19 mm or less. This allows the sheet material 10 to be appropriately broken by subsequent pressing while ensuring the minimum wall thickness in the insulator of the electric wire W.

[0039] Although the present invention has been described above based on embodiments, the present invention is not limited to the above embodiments, and modifications may be made without departing from the spirit of the invention, and if possible, the technologies of the embodiments or known or well-known technologies may be combined. [Explanation of symbols]

[0040] 10: Sheet material FM: Bundle member W: Multiple wires WH: Wire harness

Claims

1. The first step involves bundling multiple electric wires together with a sheet material to form a bundle member, A second step involves pressing the bundle member formed in the first step from the outside in the radial direction of the plurality of electric wires, thereby moving the plurality of electric wires within the sheet material so that they are arranged in a flat shape. In the third step, from the state in which the plurality of electric wires have been moved in the second step so that they are arranged in a flat shape, the bundle member is further pressed from the outside to break the sheet material, and the plurality of electric wires arranged in a flat shape are sandwiched between the sheet material. A method for manufacturing a wire harness, characterized by comprising the following features.

2. In the first step, the bundle member is formed using the sheet material having an overall or partial elongation of 150% or less and a tensile strength of 18 N / 19 mm or less, or the sheet material having an elongation of 38% or less and a tensile strength of 26 N / 19 mm or less. A method for manufacturing a wire harness according to claim 1, further comprising:

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