Corrugated tubing and wire harness

Abstract

To provide corrugated tubing and wire harnesses that can suppress a decline in appearance when installed in a vehicle. [Solution] The corrugated tube 10 is made of resin and is shaped like a cylinder to protect the electric wire W that is inserted inside it, and the surface roughness Ra on the outside of the cylinder is 1.3 μm or more. The wire harness 1 comprises such a corrugated tube 10 and an electric wire W that is inserted inside the cylinder of the corrugated tube 10, with at least a part of the corrugated tube 10 exposed as the outermost surface.

Description

[Technical Field]

[0001] The present invention relates to a corrugated tube and a wire harness. [Background Art]

[0002] Conventionally, corrugated tubes formed in a cylindrical shape that can accommodate electric wires inside the cylinder have been proposed (see, for example, Patent Documents 1 to 5). Among such corrugated tubes, there has also been proposed one in which peaks and valleys are alternately continuous in the cylindrical axial direction, and a certain degree of bending is allowed by the bellows structure formed by the continuous peaks and valleys. [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2009-166636 [Patent Document 2] Japanese Unexamined Patent Application Publication No. 2009-171649 [Patent Document 3] Japanese Unexamined Patent Application Publication No. 2010-74974 [Patent Document 4] Japanese Unexamined Patent Application Publication No. 2012-182964 [Patent Document 5] Japanese Unexamined Patent Application Publication No. 2018-19584 [Summary of the Invention] [Problems to be Solved by the Invention]

[0004] Here, corrugated tubes such as those described in Patent Documents 1 to 5 have electric wires inserted into the cylinder, and are mounted in a vehicle as a wire harness. However, corrugated tubes have a glossy surface, which causes a difference in gloss between the corrugated tube and other devices mounted on the vehicle. As a result, a difference in gloss between the corrugated tube and surrounding devices leads to a decrease in appearance.

[0005] The present invention was made to solve these conventional problems, and its objective is to provide a corrugated tube and wire harness that can suppress a deterioration in appearance when mounted on a vehicle. [Means for solving the problem]

[0006] The corrugated tube according to the present invention is a corrugated tube made of resin that is formed into a cylindrical shape and protects an electric wire inserted inside, wherein the surface roughness Ra on the outside of the cylinder is 1.3 μm or more.

[0007] Furthermore, the wire harness according to the present invention comprises the corrugated tube described above and an electric wire inserted into the tube of the corrugated tube, wherein at least a portion of the corrugated tube is exposed as the outermost surface. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide corrugated tubes and wire harnesses that can suppress a deterioration in appearance when mounted on a vehicle. [Brief explanation of the drawing]

[0009] [Figure 1] A perspective view showing a wire harness including a corrugated tube according to an embodiment of the present invention. [Figure 2] Figure 1 is a cross-sectional view of the corrugated tube along its longitudinal direction. [Figure 3] This is a diagram showing the configuration of the corrugated tube manufacturing apparatus according to this embodiment. [Figure 4] This chart shows the particle size of the abrasive material sprayed onto the divided mold during blasting, the corresponding surface roughness Ra, and the presence or absence of gloss. [Modes for carrying out the invention]

[0010] 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.

[0011] Figure 1 is a perspective view showing a wire harness including a corrugated tube according to an embodiment of the present invention. As shown in Figure 1, the wire harness 1 according to this embodiment comprises a corrugated tube 10 and electric wires W. The wire harness 1 may also further include other components such as connectors C, as shown in Figure 1.

[0012] The corrugated tube 10 is constructed in a cylindrical shape using resin. Examples of resins used include polypropylene, polyethylene, and polyamide. In the example shown in Figure 1, the corrugated tube 10 has a circular cross-sectional shape perpendicular to its longitudinal direction. However, the corrugated tube 10 is not limited to this; it may also have an oval or polygonal shape.

[0013] Figure 2 is a cross-sectional view along the longitudinal direction of the corrugated tube 10 shown in Figure 1. As shown in Figure 2, the corrugated tube 10 according to this embodiment has peaks 11 and valleys 12, and the peaks 11 and valleys 12 are arranged in an alternating continuous shape. The peaks 11 and valleys 12 are connected by slopes 13. Such a corrugated tube 10 allows for a certain degree of bending due to the bellows structure formed by the continuous peaks 11 and valleys 12.

[0014] Incidentally, the corrugated tube 10 shown in FIGS. 1 and 2 may be provided with ribs for restricting bending in a specific direction. Further, the corrugated tube 10 may have a straight tube shape without being provided with a bellows structure. In addition, in the corrugated tube 10, the inclined portion 15 is inclined with respect to the tube diameter direction orthogonal to the tube axial direction, but the invention is not limited thereto, and the inclined portion may extend parallel to the tube diameter direction.

[0015] Refer to FIG. 1 again. The electric wire W is inserted through the corrugated tube 10 and protected by the corrugated tube 10. The electric wire W includes a conductor formed of, for example, copper, aluminum, an alloy of these materials, or the like, and an insulating covering portion that covers the conductor. In the example shown in FIG. 1, the conductor of the electric wire W is a single wire, but the invention is not particularly limited thereto, and may be a stranded wire obtained by twisting a plurality of element wires. Further, in the example shown in FIG. 1, two electric wires W are provided, but the number is not limited thereto, and may be one or three or more electric wires W.

[0016] The connector C is formed of, for example, an insulating resin, and has a terminal accommodating chamber (not shown) for accommodating a terminal (not shown). A terminal is connected to a distal end of the electric wire W, and this terminal is disposed in the terminal accommodating chamber. Such a connector C is electrically connected to a mating connector side by being fitted to the mating connector.

[0017] In the wire harness 1 configured as described above, a grommet is attached or tape winding is performed as necessary, so that a part of the corrugated tube 10 becomes non-exposed. On the other hand, the remaining portion (which is an example of at least a part) of the corrugated tube 10 is in an exposed state as the outermost surface. In addition, the corrugated tube 10 is configured such that the surface roughness Ra on the outer side of the tube is 1.3 μm or more. For this reason, although the corrugated tube 10 has an exposed portion, gloss is lost to such an extent that a sense of discomfort with peripheral devices or the like is unlikely to occur in the exposed portion. Therefore, a decrease in appearance when mounted on a vehicle is suppressed.

[0018] Such a corrugated tube 10 can be manufactured by performing blast processing on a molding die for the corrugated tube 10. FIG. 3 is a configuration diagram of a manufacturing apparatus for the corrugated tube 10 according to the present embodiment.

[0019] As shown in FIG. 3, the manufacturing apparatus 100 for the corrugated tube 10 includes an extruder 110, a molding machine 120, a take-up machine 130, and a bundling winder 140. The extruder 110 melts and extrudes the resin constituting the corrugated tube 10.

[0020] The molding machine 120 includes an endless belt 121, a plurality of rollers 122, and a plurality of split molds 123. The endless belt 121 is wound around the plurality of rollers 122, and is a circumferential belt having no ends. At least one of the plurality of rollers 122 is rotationally driven by a drive source, and the rotational driving of at least one roller causes the endless belt 121 to be rotationally driven around the plurality of rollers 122. The plurality of split molds 123 are attached to the outer circumferential side of the endless belt 121, and each of the split molds is formed with shapes for forming the crests 11, troughs 12, and the like of the corrugated tube 10 by cutting or the like. The molding machine 120 includes two sets of the combination of the endless belt 121, the plurality of rollers 122, and the plurality of split molds 123, one set on the upper side and one set on the lower side.

[0021] The take-up machine 130 takes up the corrugated tube 10 molded by the molding machine 120, and the bundling winder 140 winds the corrugated tube 10 taken up by the take-up machine 130 into a roll.

[0022] The corrugated tube 10 according to the present embodiment can be manufactured by performing blast processing on the split mold 123 of the above-described manufacturing apparatus 100 to form fine irregularities on the split mold 123. FIG. 4 is a chart showing the particle size of the abrasive sprayed onto the split mold 123 during blast processing, the surface roughness Ra corresponding to the particle size, and the presence or absence of gloss.

[0023] In the experimental example shown in Figure 4, the particle size of the abrasive (alumina) conforms to "Particle size of abrasives for grinding wheels: JIS R 6001-1 and JIS R 6001-2". The surface roughness Ra is measured using a MITUTOYO SJ-201P in accordance with JIS B 0601-2001. Furthermore, gloss was measured using a KEYENCE / LR-W500 measuring instrument at a distance of 100 mm from the surface of the corrugated tube 10. A measured value of 70 or less was considered "not glossy," and a measured value greater than 70 was considered "glossy." In addition, the number of samples was 5, and samples where all were not glossy are shown as "OK" in Figure 4, while samples where at least one was glossy are shown as "NG" in Figure 4.

[0024] As shown in Figure 4, when the divided mold 123 is blasted with an abrasive material with a particle size of F60, the divided mold 123 is blasted with abrasive material of relatively large particle size. Therefore, the surface roughness Ra value on the outside of the molded corrugated tube 10 is relatively large, and the surface roughness Ra was between 2.0 μm and 2.6 μm for the five samples, with an average of 2.3 μm. The gloss was rated as "OK".

[0025] Furthermore, when the divided mold 123 is blasted with an abrasive material with a particle size of F100, the divided mold 123 is blasted with an abrasive material with a smaller particle size than the abrasive material with a particle size of F60. As a result, the surface roughness Ra value on the outside of the molded corrugated tube 10 is relatively small, and the surface roughness Ra was between 1.9 μm and 2.4 μm for the five samples, with an average of 2.0 μm. The gloss was also rated as "OK".

[0026] Furthermore, when the segmented mold 123 is blast-treated with abrasives of F150 or F180 particle size, the segmented mold 123 is blast-treated with abrasives of even smaller particle size. Therefore, the surface roughness Ra value on the outside of the molded corrugated tube 10 becomes even smaller. As a result, when blast-treated with abrasives of F150 particle size, the surface roughness Ra was between 1.4 μm and 1.9 μm for the five samples, with an average of 1.6 μm. Similarly, when blast-treated with abrasives of F180 particle size, the surface roughness Ra was between 1.3 μm and 1.8 μm for the five samples, with an average of 1.5 μm. In addition, gloss was "OK" in both cases.

[0027] On the other hand, when the segmented mold 123 is blasted with an abrasive material with a particle size of F220, the segmented mold 123 is blasted with abrasive material with very small particle sizes. As a result, the surface roughness Ra on the outside of the molded corrugated tube 10 becomes very small, ranging from 1.0 μm to 1.5 μm in five samples, with an average of 1.3 μm. Some of these corrugated tubes 10 were glossy and were deemed "NG" (not good).

[0028] Furthermore, when the divided mold 123 was blast-processed with abrasives of F70, F80, and F90, the surface roughness Ra of the corrugated tube 10 was not measured, but the gloss was rated "OK". Therefore, it can be said that the surface roughness Ra of these corrugated tubes 10 is at least within the range of 1.9 μm to 2.6 μm. When the divided mold 123 was blast-processed with abrasives of F120, the surface roughness Ra was also at least within the range of 1.4 μm to 2.4 μm, and the gloss was rated "OK".

[0029] In this manner, the corrugated tube 10 according to this embodiment has a surface roughness Ra of 1.3 μm or more on the outer surface of the tube. As a result, the corrugated tube 10 loses a degree of gloss that can easily cause a sense of incongruity with surrounding equipment. As a result, it is possible to provide a corrugated tube 10 that can suppress a decrease in appearance when mounted in a vehicle.

[0030] Furthermore, the wire harness 1 according to this embodiment comprises a corrugated tube 10 and electric wires W inside the tube, with at least a portion of the corrugated tube 10 exposed as the outermost surface. Therefore, the exposed portion of the corrugated tube 10 does not have a difference in gloss that would cause a sense of incongruity with surrounding equipment, and a wire harness 1 that does not degrade in appearance when mounted in a vehicle can be provided.

[0031] 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, publicly known or well-known technologies may be combined.

[0032] For example, in this embodiment, the corrugated tube 10 is assumed to have alternating peaks 11 and valleys 12 along its entire length. However, it is not limited to this, and the structure may be such that the peaks 11 and valleys 12 alternate only in the parts where bending is required, and the rest of the tube does not have peaks 11 and valleys 12, resulting in a straight pipe structure.

[0033] Furthermore, although the corrugated tube 10 in this embodiment has been described assuming that it does not have slits extending in the direction of the cylindrical axis, it is not limited to this, and may have slits into which the electric wire W is inserted from the side of the corrugated tube 10.

[0034] Furthermore, in this embodiment, the corrugated tube 10 is assumed to have a surface roughness Ra of 1.3 μm or more throughout its entire surface. However, it is not limited to this, and the surface roughness Ra may be 1.3 μm or more throughout the entire surface of the portion that is exposed when mounted on a vehicle as a wire harness 1. In this case, the surface roughness Ra of the portion that is not exposed may be less than 1.3 μm.

[0035] In addition, depending on the routing location of the wire harness 1, the direction of incidence of light (direct sunlight or direct light from the interior lights) entering the corrugated tube 10 can be known to some extent in advance. For this reason, the surface roughness Ra of the corrugated tube 10 may be 1.3 μm or more in the areas where light enters, and less than 1.3 μm in the areas where light does not enter. For example, since the corrugated tube 10 for a sliding door is routed near the footwell, the surface roughness Ra may be 1.3 μm or more on the upper side during routing, and less than 1.3 μm on the lower side. In this case, blasting only needs to be performed on the divided mold 123 that constitutes the upper side of the molding machine 120 shown in Figure 3. [Explanation of Symbols]

[0036] 1: Wire harness 10: Corrugated tubing W: Electric wire

Claims

1. A corrugated tube made of resin in a cylindrical shape, which protects electrical wires inserted inside, The surface roughness Ra on the outside of the cylinder is 1.3 μm or greater. A corrugated tube characterized by the following features.

2. The corrugated tube according to claim 1, The corrugated tube comprises an electric wire inserted into the tube, At least a portion of the corrugated tube is exposed as the outermost surface. A wire harness characterized by the following features.

Images