Wire harness and method for manufacturing wire harness

Abstract

The purpose of the present invention is to provide an easily fabricated wire harness having a structure in which the outer periphery of a wire bundle is covered with a coating material and wound in a spiral in a partial region along the longitudinal direction, and a manufacturing method capable of manufacturing such a wire harness. The present invention provides a wire harness 1 comprising an electric wire bundle 2 in which a plurality of electric wires 20 are gathered, and a tubular coating material 3 covering the outer periphery of the electric wire bundle 2 in a covering area 11 corresponding to a partial area along the axial direction of the electric wire bundle 2. At least a part of the covering area 11 is a spiral part 13 in which the combination of the electric wire bundle 2 and the coating material 3 is wound in a spiral. The coating material 3 is formed into a spiral in the spiral part 13.

Description

Wire harness and method for manufacturing wire harness

[0001] The present disclosure relates to a wire harness and a method for manufacturing the wire harness.

[0002] Curl cords, in which cables used for electrical connections are wound in a spiral shape to impart elasticity, are known. The spiral shape allows the cable to follow not only longitudinal expansion and contraction but also complex three-dimensional movements such as bending and twisting while minimizing damage to the conductors and coating materials that make up the cable. Patent Document 1 discloses an example of a cable that is imparted elasticity by a spiral shape, in which a harness for electrically connecting a power source and a seat in a sliding seat power supply structure for an automobile is formed with an elastic spiral portion as a middle portion of the harness. Here, the harness includes a power line, a ground line, and a sheath that collectively covers the power line and the ground line.

[0003] Japanese Patent Application Laid-Open No. 2022-30761

[0004] As described above, spirally shaped curl cords have been primarily used to allow wire harnesses to follow movements such as expansion and contraction. However, it is conceivable to use spiral shaping for purposes other than following such movements in automobiles and the like. For example, by providing a spirally shaped portion in a wire harness, the expansion and contraction of the spirally shaped portion can be utilized to adapt the wire harness to the routing path when routing the wire harness, i.e., to accommodate the tolerances of the routing path and the wire harness, and to accommodate excess length of the wire harness. Furthermore, the spirally shaped portion can also be utilized to absorb vibrations. In cases where the wire harness does not need to follow large movements, it is sufficient to provide a spiral shape not over the entire wire harness, but only in a partial region. From this perspective, it is conceivable to manufacture a wire harness having a spiral shape only in a partial region in the middle of its longitudinal direction.

[0005] In a curled cord in which a wire harness including a plurality of electric wires is formed into a spiral shape to impart stretchability, as in the embodiment of Patent Document 1, a sheath covering the outer periphery of the bundle of electric wires also contributes to stably maintaining the spiral shape and enhancing stretchability. However, when a spiral-shaped portion is formed only in a partial region in the longitudinal direction of the wire harness for the purpose of fitting to a wiring path or absorbing vibrations, a sheath is not necessarily required in regions other than the spiral-shaped region. Rather, from the viewpoint of reducing the amount of material used and from the viewpoint of convenience in connecting each electric wire constituting the wire harness to components of equipment, etc., it is preferable not to provide a sheath in regions other than the spiral-shaped region.

[0006] Typically, the sheath of a curl cord is formed by extrusion molding a polymer composition around a bundle of electric wires. Specifically, a curl cord is produced by winding a wire harness in which a sheath is extrusion-molded around a linear bundle of electric wires into a spiral shape, and then, if necessary, heating the sheath to form the spiral shape. In this case, it is not practical to extrude a sheath only in a partial region of the wire harness. Therefore, to obtain a wire harness in which a spiral shape is formed only in a partial region of the longitudinal center and no sheath is provided anywhere other than the spiral shape, the sheath once formed by extrusion molding must be removed from the outer periphery of the bundle of electric wires in areas other than the spiral shape. Alternatively, a curl cord formed to a short length is joined to both ends of an electric wire bundle without a sheath. Either method requires more steps to manufacture the wire harness, resulting in higher manufacturing costs.

[0007] In view of the above, an object of the present invention is to provide a wire harness that can be easily manufactured, in which the outer periphery of a bundle of electric wires is covered with a covering material in a partial region along the longitudinal direction and the bundle is wound in a spiral shape, and to provide a manufacturing method for manufacturing such a wire harness.

[0008] The wire harness of the present disclosure includes a wire bundle formed by gathering a plurality of electric wires, and a tubular covering material that covers the outer periphery of the wire bundle in a covering region that corresponds to a partial region along the axial direction of the wire bundle, and at least a part of the covering region is a helical portion in which the aggregate of the wire bundle and the covering material is wound in a helical shape, and the covering material is formed into a helical shape in the helical portion.

[0009] In the method for manufacturing a wire harness according to the present disclosure, the following steps are carried out in this order: a covering step of forming a covered area by arranging a tubular covering material around an outer periphery of an electric wire bundle in a partial region along the axial direction of the electric wire bundle; a spiraling step of winding the assembly of the electric wire bundle and the covering material into a spiral shape in at least a part of the covered area; and a forming step of heating the covering material to form it into a spiral shape.

[0010] The wire harness and the manufacturing method of the wire harness according to the present disclosure provide a wire harness that has a structure in which the outer periphery of a bundle of electric wires is covered with a covering material in a partial region along the longitudinal direction and wound in a spiral shape, and that can be easily manufactured, and a manufacturing method that can manufacture such a wire harness.

[0011] Fig. 1 is a side view showing a wire harness according to an embodiment of the present disclosure. Fig. 2 is a cross-sectional view of a covered area of ​​the wire harness. Figs. 3A and 3B are photographs of cross sections of a covering material cut for the wire harness in which a tubular covering material is disposed around a wire bundle, and for a wire harness in which a sheath is provided around a wire bundle, respectively. Figs. 4A to 4G are schematic cross-sectional views showing covering materials of different shapes.

[0012] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described. A wire harness according to an embodiment of the present disclosure has the following configuration.

[0013] [1] A wire harness according to an embodiment of the present disclosure includes a wire bundle formed by gathering a plurality of electric wires, and a tubular covering material that covers an outer periphery of the wire bundle in a covering region that corresponds to a partial region along the axial direction of the wire bundle, wherein at least a part of the covering region is a helical portion in which the aggregate of the wire bundle and the covering material is wound in a helical shape, and the covering material is formed into a helical shape in the helical portion.

[0014] In the above-described wire harness, a covering material is provided on the outer periphery of the wire bundle only in a partial region along the axial direction of the wire bundle, forming a covering region. At least a portion of the covering region is wound in a spiral shape to form a spiral portion. The spiral shape of the spiral portion can be utilized for purposes such as following movements such as expansion / contraction, bending, and twisting, adapting to a wiring path, and absorbing vibrations. In the spiral portion, the covering material is provided on the outer periphery of the wire bundle, allowing the wire bundle to stably maintain its spiral shape and enhancing the stretchability of the spiral portion. The covering material is formed into the spiral shape of the spiral portion, thereby particularly enhancing the effects of maintaining the spiral shape stably and enhancing the stretchability. Meanwhile, the covering material is not provided on the outer periphery of the wire bundle in areas other than the covering region including the spiral portion, thereby reducing the amount of covering material used. Furthermore, the need to remove the covering material from areas other than the spiral portion is eliminated for purposes such as connecting the electric wires constituting the wire bundle to equipment.

[0015] Here, because the covering material is configured as a tubular member, unlike when it is configured as a sheath, it does not need to be directly formed on the outer periphery of the wire bundle by a method such as extrusion molding. Instead, the covered area can be easily formed by covering the outer periphery of the wire bundle with the covering material, which has been previously formed as a tubular member having a predetermined length. Furthermore, by winding and shaping at least a portion of the covered area into a spiral shape and then preforming the covering material into a spiral shape by heating or the like, a wire harness having a spiral portion in a partial region can be easily manufactured.

[0016] [2] In the aspect of [1] above, the coating material may contain a thermoplastic polymer. Then, a tubular coating material is placed over a predetermined region of a bundle of electric wires to form a coated area, and at least a portion of the coated area is wound into a spiral shape. Then, the coating material is heated, and the softening and re-solidification of the coating material are utilized to easily and firmly shape the coating material into a spiral shape. Because thermoplastic polymers are not susceptible to denaturation even after softening by heating, a coating material containing a thermoplastic polymer is highly effective in assisting the expansion and contraction of the spiral portion after being shaped by heating.

[0017] [3] In the above aspect [1] or [2], the covering material may be configured as a heat-shrinkable tube and may be formed into a spiral shape after being heat-shrunk. This allows the covering material, which has a large outer diameter before being heat-shrunk, to be placed around the outer periphery of the electric wire bundle with a sufficient margin, and then the covering material can be heat-shrunk and fixed in place to be formed into a spiral shape. This allows for high operability in both placing the covering material around the outer periphery of the electric wire bundle and forming the assembly of the electric wire bundle and the covering material into a spiral shape.

[0018] [4] In any of the above aspects [1] to [3], the covering material may have a cross section perpendicular to the axial direction that is flat, with the turns of the spiral shape being longer in the adjacent direction. In this case, the multiple electric wires constituting the electric wire bundle occupy a wide width in the adjacent direction within the plane of the spiral shape within the area covered by the covering material, forming a spiral portion. This reduces the height of the electric wire bundle in the radial direction of the spiral shape, and even if the number of electric wires is increased, the diameter of the spiral portion in the wire harness can be kept small. Reducing the diameter of the spiral portion makes it easier to route the wire harness in a narrow space.

[0019] [5] In the aspect [4], the hollow portion of the covering material may be divided into a plurality of divided regions along the adjacent direction, and the plurality of electric wires constituting the electric wire bundle may be accommodated separately in the plurality of divided regions. In this case, it is easier to arrange the electric wires constituting the electric wire bundle over a wide range along the adjacent direction. As a result, it is easier to keep the diameter of the spiral portion small.

[0020] [6] In the aspect [5], each of the plurality of divided regions may have a flat shape that is long in the adjoining direction in the cross section. In this case, by arranging the electric wires that make up the electric wire bundle over a wide range along the adjoining direction, the effect of reducing the diameter of the spiral portion is further enhanced.

[0021] [7] In the method for manufacturing a wire harness according to an embodiment of the present disclosure, the following steps are performed in this order: a covering step of forming a covered area by arranging a tubular covering material around an outer periphery of an electric wire bundle in a partial region along the axial direction of the electric wire bundle; a spiraling step of winding the assembly of the electric wire bundle and the covering material into a spiral shape in at least a part of the covered area; and a forming step of heating the covering material to form it into a spiral shape.

[0022] In the method for manufacturing the wire harness, a tubular covering material is disposed around a bundle of electric wires in the covering step to form a covered region, and then at least a portion of the covered region is wound in a spiral shape in the spiraling step to form a spiral portion. Therefore, a wire harness having a structure in which the covering material is disposed only in a required region and wound in a spiral shape can be easily manufactured. Furthermore, by performing a forming step in which the covering material is formed into a spiral shape by heating, the covering material is stably held at a predetermined location including the spiral portion, and a state in which the spiral shape is supported for expansion and contraction can be easily formed.

[0023] [8] In the aspect [7] above, the covering material may contain a thermoplastic polymer. In this case, in the forming step, the covering material is softened by heating and then allowed to cool, thereby easily and firmly forming the covering material into a spiral shape. Furthermore, the spiral portion formed by such heating is likely to have high stretchability, including the contribution of the covering material.

[0024] [9] In the above aspect [7] or [8], the covering material may be configured as a heat-shrinkable tube, and the covering step may involve heat-shrinking the covering material arranged around the electric wire bundle, followed by the spiraling step and the pre-shaping step. In this case, in the covering step, the covering material is arranged around the electric wire bundle in a large diameter before heat-shrinking, and then heat-shrinked to fix the covering material in a predetermined covering region, and then formed into a spiral shape in the subsequent spiraling step. Therefore, both the arrangement of the covering material around the electric wire bundle and the formation of the assembly of the electric wire bundle and the covering material into a spiral shape can be easily performed.

[0025] [Details of Embodiments of the Present Disclosure] Hereinafter, a wire harness and a method for manufacturing a wire harness according to an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0026] <Configuration of Wire Harness> First, the configuration of a wire harness according to an embodiment of the present disclosure will be described. Fig. 1 shows a side view of the wire harness 1 according to the embodiment of the present disclosure. The wire harness 1 includes a wire bundle 2 and a covering material 3. The wire harness 1 also includes a covered region 11 and an exposed region 12 along the longitudinal direction (a direction in which the central axis of the entire wire harness 1 extends; in the figure, a direction extending from the upper left to the lower right, and then from the left to the right and from the upper left to the lower right). At least a part of the covered region 11 forms a spiral portion 13. Fig. 2 shows a cross section of the wire harness 1 cut perpendicular to the axial direction of the wire bundle 2 at the covered region 11.

[0027] The wire bundle 2 is an assembly of multiple electric wires 20. The number of electric wires 20 constituting the wire bundle 2 is not particularly limited, but in the illustrated embodiment, there are three. The type of electric wire 20 is also not particularly limited, and each electric wire may be configured as a single insulated electric wire in which an insulating coating 22 is formed on the outer periphery of a conductor 21, as in the illustrated embodiment, or may be configured as a composite electric wire in which multiple insulated electric wires are combined. In the wire bundle 2, the multiple electric wires 20 may be assembled simply by arranging them in the axial direction as illustrated, or may be further maintained in an assembled state by using a bundling member, twisting, or the like. However, no member formed by extrusion molding of a polymer composition, such as a sheath, is provided on the outer periphery of the wire bundle 2.

[0028] The covering material 3 is a tubular, i.e., hollow, cylindrical member that covers the outer periphery of the wire bundle 2 in a covering region 11 corresponding to a portion of the axial direction of the wire bundle 2 (the direction in which the wire bundle 2 extends). The wire bundle 2 is inserted into the hollow portion of the tubular covering material 3. The constituent material of the covering material 3 is not particularly limited, and may be an insulating material containing a polymer. Preferably, the covering material 3 contains a thermoplastic polymer and has thermoplastic properties as a whole. Examples of thermoplastic polymers that constitute the covering material 3 include various resins such as polyvinyl chloride, polyolefins such as polyethylene, polyurethane, and fluorine-based resins, various elastomers such as polyesters, polyolefins, and polystyrenes, and various rubbers such as silicone rubber. More preferably, the covering material 3 is configured as a heat-shrinkable tube. In this case, in the finished wire harness 1, the covering material 3 made of a heat-shrinkable tube is in a heat-shrinked state. In this embodiment, the cross section of the covering material 3 perpendicular to the axial direction of the wire bundle 2 has an approximately circular shape (see FIGS. 2 and 4A).

[0029] In the wire harness 1, only a partial region in the longitudinal direction is a covered region 11 in which the covering material 3 is arranged around the outer periphery of the wire bundle 2. The region other than the covered region 11 is an exposed region 12 in which the wire bundle 2 is exposed without being covered with the covering material 3. Specific positions of the covered region 11 and the exposed region 12 are not particularly specified, but as shown in the drawing, a preferred embodiment is one in which the exposed region 12 is provided at each end of the covered region 11 along the longitudinal direction of the wire harness 1. In addition, it is preferred that the total length of the exposed regions 12 along the longitudinal direction of the wire harness 1 is 0.5 times or more, further 1 time or more, or 2 times or more the total length of the covered region 11.

[0030] In the wire harness 1, at least a part of the covered region 11 in which the covering material 3 is disposed forms a spiral portion 13. In the spiral portion 13, an assembly of the wire bundle 2 and the covering material 3 is wound in a spiral shape. In the spiral portion 13, the covering material 3 also forms a spiral shape together with the wire bundle 2 while covering the outer periphery of the wire bundle 2. The spiral portion 13 is expandable and contractible along the longitudinal direction of the wire harness 1, which corresponds to the direction of the central axis of the spiral shape. As long as the spiral portion 13 is provided as at least a part of the covered region 11, the spiral portion 13 may occupy the entire covered region 11 or only a part of it. However, from the viewpoint of stably forming and holding the spiral portion 13, it is preferable that the spiral portion 13 is formed occupying a part of the covered region 11, and that portions of the covered region 11 that are not wound in a spiral shape are left at both ends of the spiral portion 13, as shown in FIG. 1 . The entire exposed region 12 is not wound in a spiral shape, and the wire bundle 2 is maintained in a linearly stretched state.

[0031] The coating material 3 is formed into a helical shape at the helical portion 13. Specifically, the coating material 3 is in close contact with the outer periphery of the electric wire bundle 2 in the coated area 11, including the helical portion 13. In addition, at the helical portion 13, the coating material 3 also maintains a helical shape as the shape of the coating material 3 itself, following the helical shape of the electric wire bundle 2. In other words, when the helical portion 13 is deformed by expansion, contraction, bending, twisting, or the like, the coating material 3 alone exerts a certain degree of restoring force and tries to maintain its original helical shape. When the coating material 3 is configured as a heat-shrinkable tube, the coating material 3 is further formed into a helical shape in a heat-shrunk state.

[0032] As described above, the covering material 3 is in close contact with the outer periphery of the wire bundle 2 in the covered region 11 including the spiral portion 13. However, since the covering material 3 is configured as a tubular member and covers the outer periphery of the wire bundle 2, as will be described in detail in the next section on the manufacturing method of the wire harness 1, a certain amount of gap remains between the covering material 3 and the wire bundle 2. Furthermore, even in the area where the covering material 3 is in close contact with the wire bundle 2, the covering material 3 does not adhere firmly to the wire bundle 2, and the covering material 3 can be easily peeled off from the surface of the wire bundle 2 by manual work or the like (however, this does not apply when an adhesive is used between the wire bundle 2 and the covering material 3, such as when the covering material 3 is configured as a heat-shrinkable tube with an adhesive). For example, Fig. 3A shows a photograph of a cross section of a covered region configured using a tubular covering material, in which a large gap is formed at the location indicated by the arrow. If the covering material is configured as a sheath obtained by extruding a polymer composition, the sheath will be firmly attached to the surface of the wire bundle with almost no gap remaining between the sheath and the wire bundle, as shown in the cross-sectional photograph of Fig. 3B . The size of the gap formed between the tubular covering material 3 and the wire bundle 2 can be, for example, 10% or more, or 20% or more, in terms of the area ratio of the area surrounded by the inner surface of the covering material 3 in a cross section of the covered region 11 cut perpendicular to the axial direction of the wire bundle 2.

[0033] <Method for Manufacturing Wire Harness> Next, as a method for manufacturing a wire harness according to an embodiment of the present disclosure, an example of a method for manufacturing the wire harness 1 having the above-described structure will be described. In this manufacturing method, a covering step, a spiraling step, and a forming step are performed in this order.

[0034] In the covering process, the covering material 3 is placed at a predetermined position on the outer periphery of the electric wire bundle 2 to form the covered area 11. Specifically, first, a plurality of electric wires 20 are bundled together to prepare the electric wire bundle 2, and the covering material 3 is also prepared. The covering material 3 may be prepared by forming a tubular material by extrusion or the like and cutting it to a length corresponding to the covered area 11 to be formed. The prepared covering material 3 is then placed on the outer periphery of the electric wire bundle 2, i.e., the electric wire bundle 2 is inserted into the hollow portion of the covering material 3, and the covering material 3 is placed at the position where the covered area 11 is to be formed. Furthermore, if the covering material 3 is configured as a heat-shrinkable tube, the covering material 3 is heated and heat-shrunk while it is placed on the outer periphery of the electric wire bundle 2 at a predetermined position. This fixes the covering material 3 in the predetermined position. Regarding the dimensions of the covering material 3 used in this covering step, if the covering material 3 does not have heat shrinkability, the inner diameter of the hollow portion may be set to be large enough to allow the electric wire bundle 2 to be inserted therethrough, and small enough to allow the covering material 3 to be tightly fitted to the outer periphery of the electric wire bundle 2 after a subsequent forming step. On the other hand, if the covering material 3 is configured as a heat shrink tube, it is preferable to use one with an inner diameter large enough to allow the electric wire bundle 2 to be inserted therethrough with sufficient room to spare.

[0035] Next, in the spiraling step, a spiral portion 13 is formed in at least a part of the covered region 11 formed in the covering step. At this time, the assembly of the wire bundle 2 and the covering material 3 is wound around the outer periphery of a rod-shaped shaft member, and the assembly is formed into a spirally wound state. The wire bundle 2 is left in a linearly stretched state in the exposed region 12 and other regions other than the region where the spiral portion 13 is to be formed.

[0036] Finally, a forming step is performed to form the coating material 3 into the spiral shape formed in the spiraling step. The forming step can be performed by heating the coating material 3 and then allowing it to cool. The polymer material constituting the coating material 3 is heated and maintains the spiral shape it has at the time of heating, thereby forming the coating material 3. In particular, if the coating material 3 has thermoplasticity, the coating material 3 is heated to a temperature higher than the softening temperature of the thermoplastic polymer constituting the coating material 3 and then allowed to cool, so that the once softened coating material 3 solidifies while maintaining its spiral shape, thereby firmly maintaining the spiral shape. Even if the coating material 3 is configured as a heat-shrinkable tube and has been heat-shrunk in the previous coating step, a forming step is performed by heating again after the spiraling step. The heating in the forming step may be performed using a heating furnace, for example. Furthermore, in the previous spiraling step, if a shaft member is used to form the spiral shape, heating may be performed while the assembly of the electric wire bundle 2 and the covering material 3 is still wound around the outer periphery of the shaft member, or after the shaft member is removed. The heating temperature in the forming step is preferably kept within a range in which the covering material 3 can maintain a tubular shape having a hollow portion.

[0037] <Uses and Characteristics of Wire Harness> The wire harness 1 according to this embodiment has the helical portion 13 in which the wire bundle 2 is wound in a helical shape. Therefore, by utilizing the deformation of the helical portion 13, the wire harness 1 can deform in accordance with various movements, such as expansion, contraction, bending, and twisting. Therefore, by utilizing the wire harness 1 for electrical connection between moving members, such as a sliding seat in an automobile, the wire harness 1 can follow these movements while maintaining stable electrical connection. In addition to following these movements, the helical portion 13 can also be used to enable the wire harness 1 to adapt to a wiring route. Examples of adaptation to a wiring route include accommodating tolerances in the length of the wire harness 1 and the wiring route, and accommodating excess length of the wire harness 1. For example, if the longitudinal dimension of the wire harness 1 is slightly shorter than the wiring route, the helical portion 13 can be extended to adapt to the wiring route. Furthermore, even when the longitudinal dimension of the wire harness 1 is longer than the wiring route, the wire harness 1 has the spiral portion 13, which can prevent the excess length of the wire harness 1 from bending significantly or interfering with surrounding components. Furthermore, when vibration is applied to the wire harness 1 after wiring, the spiral portion 13 absorbs the vibration by deformation such as expansion and contraction, thereby reducing the impact of the vibration on the wire harness 1 and connected devices. These adaptations to the wiring route and vibration absorptions can be effectively utilized in applications such as inside an automobile where the space in which the wire harness can be wired is significantly restricted and where the wire harness is susceptible to the effects of vibration, and contribute to improving the convenience of wiring the wire harness 1 and the vibration resistance.

[0038] As described above, when the spiral portion 13 is provided for an application that does not aim to follow large movements, such as fitting to a wiring path or absorbing vibrations, the spiral portion 13 does not need to undergo significant deformation, such as expansion and contraction. That is, in the wire harness 1, the spiral portion 13 does not necessarily need to occupy the entire longitudinal area or a large area nearly so; it is sufficient if it is formed to occupy only a partial area. The wire harness 1 according to this embodiment is provided with the spiral portion 13 only in a partial area in the longitudinal direction, and is suitable for such applications. By limiting the area where the spiral portion 13 is provided to a partial area of ​​the wire harness 1, the actual length of the wire bundle 2 constituting the wire harness 1 can be reduced. Furthermore, the area where the spiral portion 13 occupies a large space due to the wire harness 1 can also be reduced.

[0039] In the spiral portion 13, the assembly of the wire bundle 2 and the covering material 3 is formed into a spiral shape with the covering material 3 disposed around the outer periphery of the wire bundle 2. This prevents the electric wires 20 constituting the wire bundle 2 from coming apart, and allows the wire bundle 2 to stably maintain the spiral shape. Furthermore, the covering material 3 itself enhances the springiness of the spiral portion 13, assists expansion and contraction, and plays a role in making it easier for the spiral portion 13 to maintain high flexibility even when repeatedly expanded and contracted. In particular, the covering material 3 is formed into a spiral shape, which effectively maintains the spiral shape stably and assists expansion and contraction. As such, the covering material 3 imparts a function to the spiral portion 13, but providing the covering material 3 in areas other than the spiral portion 13 is less meaningful. In fact, not providing the covering material 3 in areas other than the spiral portion 13 reduces the amount of covering material 3 used. Furthermore, when connecting each of the electric wires 20 constituting the electric wire bundle 2 to various devices, etc., it is necessary to dissolve the bundled state of the electric wire bundle 2. However, since the exposed area 12 where the covering material 3 is not initially placed is provided, there is no need to remove the covering material 3, sheath, or other components that cover the outer periphery of the electric wire bundle 2 and bundle the plurality of electric wires 20 together.

[0040] By configuring the covering material 3 as a tubular member and disposing it on the outer periphery of the wire bundle 2, unlike when a sheath is formed by extrusion molding, the manufacturing process of the wire harness 1 can easily perform an operation of forming the covered region 11 only in a necessary region of the wire bundle 2 and leaving the other region as the exposed region 12. Furthermore, by forming the covering material 3 in a region including the helical portion 13 and adhering it to the outer periphery of the wire bundle 2, the covering material 3 can be stably held in the predetermined covered region 11. In particular, when the covering material 3 contains a thermoplastic polymer, the forming can be easily and firmly performed by heating. Since the physical properties of a thermoplastic polymer are unlikely to change even after heating in the forming process, the original physical properties of the material can be utilized to, for example, enhance the stretchability of the helical portion 13. Furthermore, when the covering material 3 is configured as a heat-shrinkable tube, the covering material 3, which has a large diameter before heat shrinking, can be fitted with a sufficient margin around the outer periphery of the electric wire bundle 2, making it particularly easy to arrange the covering material 3. On the other hand, by heat-shrinking the covering material 3 arranged at a predetermined position, the covering material 3 can be formed into a spiral shape with high operability while being stably fixed at the predetermined position.

[0041] <Wire Harness According to Modified Embodiments> Here, as modified embodiments of the wire harness 1 of the present disclosure, cases where the covering material 3 takes various shapes will be described. In the embodiment described in detail above, the cross-sectional shape of the covering material 3 can be approximated to a circle. FIG. 4A schematically shows the cross-sectional shape of the circular covering material 3. However, the cross-sectional shape of the covering material 3 is not limited to this circular shape. FIGS. 4B to 4G schematically show cross-sectional shapes of the covering material 3 having various shapes. Hereinafter, unless otherwise specified, the cross-section of the covering material 3 refers to a cross-section of the covering material 3 perpendicular to the axial direction of the wire bundle 2 in the wire harness 1, that is, a cross-section perpendicular to the axis of the tubular shape of the covering material 3. Furthermore, when the covering material 3 is configured as a heat-shrinkable tube, the cross-sectional shape mainly refers to the shape before heat shrinking.

[0042] A suitable example of the dressing 3 having a cross-sectional shape other than a circle is one having a flattened cross-section. In this case, the cross-sectional shape of the dressing 3 is elongated in the adjacent direction (direction A), which is the direction in which the turns of the spiral shape are adjacent in the helical portion 13. In other words, the cross-section of the dressing 3 has a shape in which the dimension in the adjacent direction A is larger than the dimension in the radial direction of the spiral shape, which is the direction perpendicular to the adjacent direction A. Note that in Figures 4A to 4G, the horizontal direction in the figures is the adjacent direction A.

[0043] Examples of a covering material 3 having a flat cross section are shown in Figures 4B to 4D. The cross section of the covering material 3 is elliptical in Figure 4B, oval in Figure 4C (a shape formed by joining semicircles to both ends of a rectangle; resembling an athletics track), and rectangular in Figure 4D. As described above, the cross section of the covering material 3 has a flat shape with a hollow portion elongated in the adjacent direction A. This allows the multiple electric wires 20 constituting the electric wire bundle 2 to be arranged in a wide area within the hollow portion of the covering material 3 along the adjacent direction A, which occupies the plane of the spiral shape. This reduces the height (thickness) occupied by the electric wires 20 along the radial direction facing outward from the plane of the spiral shape. This allows the diameter of the spiral portion 13 in the wire harness 1 to be kept small. As a result, even when the number of electric wires 20 constituting the electric wire bundle 2 is large, the wire harness 1 can be routed in a small space. Furthermore, the space-saving properties of the wire harness 1 are improved. The aspect ratio of the flat cross section of the covering material 3, that is, the ratio of the dimension in the adjacent direction A to the dimension in the radial direction of the spiral shape, is not particularly limited, but is preferably 2 or more, for example.

[0044] Furthermore, in a covering material 3 having a flat cross section, it is preferable that the tubular hollow portion be partitioned into multiple segmented regions 3A along the adjacent direction A. In other words, the covering material 3 is configured as a structure in which multiple hollow segmented regions 3A are arranged in the adjacent direction A, and the overall cross-sectional shape of the covering material 3 containing these multiple segmented regions 3A is preferably a flat shape elongated in the adjacent direction A. Examples of such configurations in which the hollow portion of the covering material 3 is partitioned into multiple segmented regions 3A are shown in Figures 4E to 4G. In Figure 4E, multiple tubular covering materials (subtubes) are aligned in the adjacent direction A and joined to each other. The subtubes can be joined by adhesive bonding, thermal fusion, or by dissolving and joining portions of the surface with a solvent. In Figure 4F, multiple connected tubular shapes are integrally formed by extrusion molding of a polymer material, for example. In FIG. 4G, the covering material 3 is formed as an extrusion molded body having a shape of a smooth plate-like member that is long in the adjoining direction A as a whole and has a plurality of through holes.

[0045] In this manner, in the covering material 3 whose hollow portion is divided into a plurality of segmented regions 3A, the plurality of electric wires 20 constituting the electric wire bundle 2 are accommodated separately in the plurality of segmented regions 3A. That is, one or more, preferably a plurality of, electric wires 20 are accommodated in each of the plurality of segmented regions 3A. Being able to accommodate the plurality of electric wires 20 divided into the plurality of segmented regions 3A in this manner makes it easier to arrange the electric wires 20 constituting the electric wire bundle 2 in a wider space in the adjacent direction A than in the case where the flat hollow portion is configured as a single continuous space as shown in FIGS. 4B to 4D . This also makes it easier to achieve the effect of reducing the diameter of the spiral portion 13 in the wire harness 1. Note that when using a covering material 3 to which a plurality of sub-tubes are joined as shown in FIG. 4E , it is possible to either insert the electric wires 20 into each sub-tube before joining the sub-tubes, or to join the plurality of sub-tubes and then insert the electric wires 20 into each sub-tube.

[0046] Furthermore, each of the multiple segment regions 3A may have a cross-sectionally elongated flat shape in the adjacent direction A. That is, the sub-tubes, hollow portions, and through holes constituting each segment region 3A may not be circular, but may have a flat shape elongated in the adjacent direction A, similar to the coating material 3 shown in FIGS. 4B to 4D . In this case, it is easy to form the coating material 3 into a shape particularly elongated in the adjacent direction A. Therefore, the effect of arranging the electric wires 20 constituting the electric wire bundle 2 to occupy a wide space in the adjacent direction A and keeping the diameter of the spiral portion 13 small can be particularly effectively achieved.

[0047] The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the present invention.

[0048] REFERENCE SIGNS LIST 1 Wire harness 11 Covered area 12 Exposed area 13 Helical portion 2 Wire bundle 20 Electric wire 21 Conductor 22 Insulating coating 3 Coating material 3A Divided area A Adjacent direction

Claims

1. A wire harness comprising: an electric wire bundle comprising a plurality of electric wires; and a tubular covering material covering the outer periphery of the electric wire bundle in a covering region corresponding to a partial region along the axial direction of the electric wire bundle, wherein at least a portion of the covering region is a spiral portion in which the assembly of the electric wire bundle and the covering material is wound in a spiral shape, and the covering material is formed into a spiral shape in the spiral portion.

2. The wire harness according to claim 1, wherein the covering material includes a thermoplastic polymer.

3. The wire harness according to claim 1, wherein the covering material is configured as a heat-shrinkable tube and is formed into a spiral shape in a heat-shrinked state.

4. A wire harness as claimed in any one of claims 1 to 3, wherein the cross section of the covering material perpendicular to the axial direction has a flat shape that is long in the direction in which the spiral turns are adjacent.

5. The wire harness according to claim 4, wherein the hollow portion of the covering material is divided into a plurality of divided regions along the adjoining direction, and the plurality of electric wires constituting the electric wire bundle are housed separately in the plurality of divided regions.

6. The wire harness according to claim 5, wherein each of the plurality of divided regions has a flat shape in the cross section that is long in the adjoining direction.

7. A method for manufacturing a wire harness, comprising the steps of: a covering step of forming a covered area by arranging a tubular covering material around an electric wire bundle in a partial area along the axial direction of the electric wire bundle; a spiraling step of winding the assembly of the electric wire bundle and the covering material into a spiral shape in at least a part of the covered area; and a forming step of heating the covering material to form it into a spiral shape, in this order.

8. The method for manufacturing a wire harness according to claim 7, wherein the covering material includes a thermoplastic polymer.

9. The method for manufacturing a wire harness according to claim 7 or 8, wherein the covering material is configured as a heat-shrinkable tube, and the covering step involves heat-shrinking the covering material arranged around the outer periphery of the bundle of electric wires, and then carrying out the spiraling step and the crimping step.

Images