Corrugated tube and wire harness

The invention includes a tubular main body that protects an electric wire accommodated in an internal space, and a tubular or annular outer layer body stacked concentrically with the main body on an outer peripheral surface of the main body. The outer layer body is either a molded body formed into a shape having a hardness lower than that of the main body, and capable of absorbing sound when the outer layer body comes into contact with an external contacting object, or a molded body including a material having a hardness lower than that of the main body, and capable of absorbing sound when the outer layer body comes into contact with an external contacting object.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application claims priority to and incorporates by reference the entire contents of Japanese Patent Application No. 2018-178619 filed in Japan on Sep. 25, 2018.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a corrugated tube and a wire harness.

2. Description of the Related Art

Conventionally, a corrugated tube is known as an exterior member for protecting an electric wire from the outside.

A corrugated tube covers an electric wire from the outside to protect it from external peripheral parts, by accommodating the electric wire in the internal space of a tubular main body. For example, Japanese Patent Application Laid-open No. 2016-152714 and Japanese Patent Application Laid-open No. 2016-152715 below disclose a corrugated tube having a cylindrically formed main body and a soft cushioning portion provided on an inner wall surface of the main body. In the corrugated tube of Japanese Patent Application Laid-open No. 2016-152714 and Japanese Patent Application Laid-open No. 2016-152715, the function of protecting the electric wire is enhanced by bringing the cushioning portion into contact with the electric wire to avoid contact of the main body with the electric wire. Note that the corrugated tube forms a wire harness together with the electric wire or the like which is a part to be protected.

Incidentally, in a corrugated tube, in order to protect an electric wire from external peripheral parts, a main body is formed to have a hardness suitable for the protection. For this reason, in a case where the corrugated tube is spaced apart from peripheral parts, the corrugated tube may generate sound when the outer surface of the main body comes into contact with the peripheral parts. For example, in a case where the corrugated tube is mounted on a vehicle such as an automobile along with the electric wire, an external force caused by road surface input or the like is transmitted to the electric wire or the corrugated tube. At this time, the corrugated tube coming into contact with a peripheral part such as a vehicle body may generate sound recognized as abnormal noise.

SUMMARY OF THE INVENTION

In view of the foregoing, it is an object of the present invention to provide a corrugated tube and a wire harness that can suppress occurrence of abnormal noise.

To achieve the object, a corrugated tube according to one aspect of the present invention includes a tubular main body that protects an electric wire accommodated in an internal space; and a tubular or annular outer layer body stacked concentrically with the main body on an outer peripheral surface of the main body, wherein the outer layer body is a molded body formed into a shape having a hardness lower than that of the main body, and capable of absorbing sound when the outer layer body comes into contact with an external contacting object.

A corrugated tube according to another aspect of the present invention includes a tubular main body that protects an electric wire accommodated in an internal space; and a tubular or annular outer layer body stacked concentrically with the main body on an outer peripheral surface of the main body, wherein the outer layer body is a molded body including a material having a hardness lower than that of the main body, and capable of absorbing sound when the outer layer body comes into contact with an external contacting object.

According to still another aspect of the present invention, in the corrugated tube, it is preferable that the main body and the outer layer body are an integral molded body molded integrally with each other.

According to still another aspect of the present invention, in the corrugated tube, it is preferable that the main body is a bellows-shaped molded body in which an annular recess recessed on a side of the outer peripheral surface and an annular protrusion protruding on a side of the outer peripheral surface are concentrically and alternately connected along a cylinder axis direction, and the outer layer body is a bellows-shaped molded body in which an annular layer recess stacked concentrically with the annular recess on an outer peripheral surface of the annular recess and an annular layer protrusion stacked concentrically with the annular protrusion on an outer peripheral surface of the annular protrusion are concentrically and alternately connected along the cylinder axis direction.

According to still another aspect of the present invention, in the corrugated tube, it is preferable that the main body is a bellows-shaped molded body in which an annular recess recessed on a side of the outer peripheral surface and an annular protrusion protruding on a side of the outer peripheral surface are concentrically and alternately connected along a cylinder axis direction, and the outer layer body is an annular molded body provided for each of the annular protrusions, and stacked concentrically with the annular protrusion on an outer peripheral surface of the annular protrusion.

To achieve the object, a wire harness according to still another aspect of the present invention includes an electric wire; and a corrugated tube that protects the electric wire from an outside, wherein the corrugated tube includes a tubular main body that protects the electric wire accommodated in an internal space, and a tubular or annular outer layer body stacked concentrically with the main body on an outer peripheral surface of the main body, and the outer layer body is a molded body formed into a shape having a hardness lower than that of the main body, and capable of absorbing sound when the outer layer body comes into contact with an external contacting object.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of a corrugated tube and a wire harness according to the present invention will be described in detail with reference to the drawings. Note that the invention is not limited by this embodiment.

Embodiment

One embodiment of the corrugated tube and the wire harness according to the present invention will be described with reference toFIGS. 1 to 4.

Reference symbol1inFIGS. 1 to 4denotes the corrugated tube of the embodiment. Moreover, reference symbol WH inFIGS. 2 and 4denotes the wire harness of the embodiment.

The corrugated tube1is an exterior member for protecting an electric wire We from the outside (FIGS. 2and4). The corrugated tube1is used to protect an electric wire We arranged in a vehicle such as an automobile from a peripheral part Pn (FIG. 4) such as a vehicle body, for example. The corrugated tube1forms the wire harness WH together with at least one electric wire We which is a part to be protected. For example, in the wire harness WH mounted on a vehicle, the required number of corrugated tubes1are provided in the entire electric wire We except for a connector joining point or the like and/or a part of the electric wire We that needs to be protected from the peripheral part Pn.

The corrugated tube1includes a cylindrical main body10that protects the electric wire We accommodated in an internal space S (FIGS. 1, 3, and 4). The main body10is a molded body formed of an insulating material such as a synthetic resin. For example, the main body10is formed using a polypropylene resin, a polyamide resin, or the like as the material.

In this example, the main body10is formed in a bellows shape. Accordingly, in the exemplified main body10, an annular recess11recessed on the outer peripheral surface side and an annular protrusion12protruding on the outer peripheral surface side are concentrically and alternately connected along the cylinder axis direction (FIGS. 3 and 4). Here, the main body10is formed as a substantially cylindrical and bellows-shaped molded body including multiple ring-shaped annular recesses11and multiple ring-shaped annular protrusions12.

Furthermore, the corrugated tube1includes a tubular outer layer body20stacked concentrically with the main body10on an outer peripheral surface of the main body10(FIGS. 1 to 4). The outer layer body20is a molded body formed of an insulating material such as a synthetic resin.

The outer layer body20is provided to suppress generation of abnormal noise when the outer layer body20comes into contact with the peripheral part Pn. Hence, the outer layer body20is formed to be a molded body having a shape whose hardness is lower than that of the main body10, and capable of absorbing sound when the outer layer body20comes into contact with the peripheral part Pn which is an external contacting object. As the insulating material forming the outer layer body20, a material is used which has a hardness lower than that of the material forming the main body10, and is capable of absorbing sound when the outer layer body20comes into contact with the peripheral part Pn which is an external contacting object. As this insulating material, a material is selected which can achieve a desired sound absorbing effect depending on the thickness of the outer layer body20in the stacking direction, the material of the peripheral part Pn, the shape of the peripheral part Pn, and the like. For example, the outer layer body20is formed of a material such as a polyolefin resin, a polyamide resin, a vinyl chloride resin, a silicone resin, a fluororesin, a polycarbonate resin, a polyimide resin, a polyester resin, or a polyurethane resin.

The outer layer body20may be formed integrally with the outer peripheral surface of the main body10, or may be applied and formed on the outer peripheral surface of the main body10, for example.

The exemplified main body10and outer layer body20are an integral molded body molded integrally with each other. For example, the corrugated tube1is formed by extruding the material forming the main body10and the material forming the outer layer body20in the form of concentrically stacked cylinders by an extruder (not shown), and sending the resultant product to a molding machine (not shown) to form the bellows shape with the forming mold. Hence, it is desirable to use the same series of materials for the main body10and the outer layer body20. Thus, the main body10and the outer layer body20can be integrated with each other without using an adhesive or the like.

Specifically, the outer layer body20of the embodiment is formed into a tubular and bellows-shaped molded body concentric with the main body10. Accordingly, in the outer layer body20, an annular layer recess21stacked concentrically with the annular recess11on an outer peripheral surface of the annular recess11and an annular layer protrusion22stacked concentrically with the annular protrusion12on an outer peripheral surface of the annular protrusion12are concentrically and alternately connected along the cylinder axis direction (FIGS. 3 and 4). Here, the outer layer body20is formed as a substantially cylindrical and bellows-shaped molded body including multiple ring-shaped annular layer recesses21and multiple ring-shaped annular layer protrusions22.

With this corrugated tube1, even if an external force caused by road surface input or the like is transmitted and accidentally brings the corrugated tube1into contact with the peripheral part Pn, the outer layer body20is brought into contact with the peripheral part Pn without bringing the main body10into contact the peripheral part Pn. Hence, the corrugated tube1can allow the outer layer body20to absorb sound generated when the corrugated tube1comes into contact with the peripheral part Pn, and can therefore suppress generation of abnormal noise at this time.

Thus, the corrugated tube1of the embodiment can not only exhibit the function of protecting the electric wire We, which is the original function, but also suppress generation of abnormal noise when the corrugated tube1accidentally comes into contact with the peripheral part Pn. Moreover, the wire harness WH of the embodiment includes the corrugated tube1, and can similarly achieve the effect exhibited by the corrugated tube1.

Modification

Reference numeral2inFIG. 5denotes a corrugated tube of a modification. The corrugated tube2is the corrugated tube1included in the wire harness WH of the embodiment in which the outer layer body20is replaced with an outer layer body120described below.

Similar to the outer layer body20of the embodiment, the outer layer body120is provided to suppress generation of abnormal noise when the outer layer body120comes into contact with a peripheral part Pn. Hence, the outer layer body120is formed using a material similar to that of the outer layer body20of the embodiment. As in the case of the outer layer body20, the outer layer body120may be formed integrally with an outer peripheral surface of a main body10, or may be applied and formed on the outer peripheral surface of the main body10. In the modification, too, the main body10and the outer layer body120are an integral molded body molded integrally with each other.

The outer layer body120of the modification is an annular molded body stacked concentrically with the main body10on the outer peripheral surface of the main body10. Specifically, the outer layer body120is provided for each of annular protrusions12of the main body10, and is provided as an annular molded body stacked concentrically with the annular protrusion12on an outer peripheral surface of the annular protrusion12of the main body10.

The corrugated tube2of the modification is provided with the outer layer body120for each of the annular protrusions12, and an outer peripheral surface of each of annular recesses11is exposed. However, similar to the corrugated tube1of the embodiment, the outer layer body120can be brought into contact with the peripheral part Pn without bringing the main body10into contact with the peripheral part Pn. Hence, the corrugated tube2can allow the outer layer body120to absorb sound generated when the corrugated tube2comes into contact with the peripheral part Pn, and can therefore suppress generation of abnormal noise at this time.

Thus, similar to the corrugated tube1of the embodiment, the corrugated tube2of the modification can not only exhibit the function of protecting an electric wire We, which is the original function, but also suppress generation of abnormal noise when the corrugated tube2accidentally comes into contact with the peripheral part Pn. Moreover, a wire harness WH of the modification includes the corrugated tube2, and can similarly achieve the effect exhibited by the corrugated tube2.

With a corrugated tube according to the present embodiment, even if the corrugated tube is accidentally brought into contact with a peripheral part, an outer layer body is brought into contact with the peripheral part without bringing the main body into contact the peripheral part. Hence, the corrugated tube can allow the outer layer body to absorb sound generated when the corrugated tube comes into contact with the peripheral part, and can therefore suppress generation of abnormal noise at this time. Thus, the corrugated tube according to the present embodiment can not only exhibit the function of protecting an electric wire, which is the original function, but also suppress generation of abnormal noise when the corrugated tube accidentally comes into contact with a peripheral part. Moreover, a wire harness according to the present embodiment includes the above corrugated tube, and can similarly achieve the effect exhibited by the corrugated tube.