Manufacturing method for electric wire with grommet

Abstract

To provide a manufacturing method of an electric wire provided with a grommet, that improves workability when inserting the electric wire in the grommet.SOLUTION: A manufacturing method of an electric wire provided with a grommet comprising at least one inner side insertion hole 3A provided in an inner side area 20A including a central axis C of an electric wire insertion part 20, and a plurality of outer side insertion holes 3B provided at positions separated away from the central axis C across the inner side area 20A comprises: an insertion hole diameter-enlarging step of diameter-enlarging the plurality of outer side insertion holes 3B and at least the one inner side insertion hole 3A without inserting the jig 10 in at least the one inner side insertion hole 3A by inserting a jig 10 in each of the plurality of outer side insertion holes 3B and moving the jig 10 in a direction separating away from the central axis C; and an electric wire insertion step of inserting an electric wire in each of the plurality of outer side insertion holes 3B and at least the one inner side insertion hole 3A that are diameter-enlarged by the insertion hole diameter-enlarging step.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a grommet-equipped electric wire. [Background technology]

[0002] Conventionally, in order to protect a wire harness passing through an opening in a vehicle body panel and to ensure waterproofing of the opening, a grommet may be interposed between the inner edge of the opening and the wire harness (see, for example, Patent Document 1).

[0003] The conventional grommet disclosed in Patent Document 1 is formed as a substantially cylindrical solid body made of rubber or elastomer, and is configured with electric wire insertion holes therethrough for inserting each of a plurality of electric wires.

[0004] When inserting an electric wire into a wire insertion hole provided in such a conventional grommet, a tool called a diameter expander is generally used to expand the diameter of each wire insertion hole. The diameter expander has portions called claws that are inserted into the wire insertion hole. The claws of the diameter expander are inserted into the wire insertion hole of the grommet and moved radially outward of the wire insertion hole. This expands the diameter of the wire insertion hole, making it easier to insert the electric wire into the expanded wire insertion hole. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-230065 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when inserting an electric wire into an electric wire insertion hole provided in a conventional grommet, a diameter expanding operation is performed in which the claws of a diameter expander are inserted into the electric wire insertion hole of the grommet and moved radially outward of the electric wire insertion hole in four directions perpendicular to the axis of the grommet to expand the diameter of the electric wire insertion hole. Therefore, for example, in a case where a group of electric wire insertion holes 120, each having two vertical and two horizontal wire insertion holes 103 for a total of four, is arranged horizontally, as in the case of grommet 102 shown in Fig. 5, two diameter expanding operations are required, which increases the number of diameter expanding operations.

[0007] An object of the present invention is to provide a method for manufacturing a grommet-attached electric wire that improves the workability when inserting an electric wire into a grommet. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, the invention described in claim 1 is a manufacturing method for a grommet-attached electric wire, in which an electric wire is inserted into a grommet having an electric wire insertion portion for inserting the electric wire from one side to the other, the electric wire insertion portion being formed in a cylindrical shape with a central axis extending from the one side to the other, the grommet having at least one inner insertion hole provided in an inner region including the central axis of the electric wire insertion portion, and a plurality of outer insertion holes provided at positions away from the central axis across the inner region, the manufacturing method for a grommet comprising: an insertion hole expanding step of inserting a jig into each of the plurality of outer insertion holes and the inner insertion hole, and moving the jig in a direction away from the central axis without inserting the jig into the inner insertion hole; and an electric wire insertion step of inserting the electric wire into each of the plurality of outer insertion holes and the inner insertion hole expanded in the insertion hole expanding step. [Effects of the Invention]

[0009] According to the present invention, it is possible to improve the workability when inserting an electric wire into a grommet. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view showing a grommet constituting a method for manufacturing a grommet-equipped electric wire according to an embodiment of the present invention. FIG. [Figure 2] FIG. [Figure 3] 10 is a diagram for explaining the manufacturing method of the grommet-attached electric wire, showing a state in which the claws of a diameter expander are inserted into each of a plurality of outer insertion holes. FIG. [Figure 4] 4 is a diagram showing a step subsequent to that shown in FIG. 3, showing a state in which the diameters of the outer insertion holes and the inner insertion holes have been enlarged. FIG. [Figure 5] FIG. 1 is a plan view showing a conventional grommet. DETAILED DESCRIPTION OF THE INVENTION

[0011] A method for manufacturing a grommeted electric wire according to one embodiment of the present invention will be described below with reference to Figs. 1 to 4. Fig. 1 is a perspective view showing a grommet 2 constituting a method for manufacturing a grommeted electric wire according to one embodiment of the present invention. Fig. 2 is a plan view showing the grommet 2. Fig. 3 is a diagram for explaining the method for manufacturing a grommeted electric wire, showing a state in which the claws 10 (jig) of a diameter expander are inserted into each of a plurality of outer through-holes 3B. Fig. 4 is a diagram showing a step subsequent to Fig. 3, showing a state in which each of a plurality of outer through-holes 3B and inner through-holes 3A has been expanded in diameter.

[0012] The grommet 2 that constitutes the manufacturing method for a grommet-equipped electric wire according to this embodiment is configured so that an electric wire (not shown) can be inserted therethrough, and is attached to an attachment hole formed in a panel, partition wall, etc. (hereinafter referred to as the "attachment target") (not shown) for the purpose of waterproofing, dustproofing, and soundproofing the attachment hole.

[0013] As shown in FIGS. 1 and 2, grommet 2 integrally includes an electric wire insertion portion 20 through which an electric wire is inserted, and an attachment portion 21 that can be fitted into an attachment hole provided in an attachment target (not shown).

[0014] The wire insertion portion 20 is formed in a cylindrical shape extending in one direction as shown in Fig. 1. An electric wire (not shown) is inserted into the wire insertion portion 20, and the inserted electric wire is guided and held along the axial direction Y (one direction).

[0015] 1, the axial direction Y of the wire insertion portion 20 is defined as the axial direction Y of the entire grommet 2. The radial direction of the wire insertion portion 20 that is perpendicular to the axial direction Y (longitudinal direction) of the wire insertion portion 20 is defined as the radial direction of the mounting portion 21 and the entire grommet 2. Furthermore, the central axis C (axial core) of the wire insertion portion 20 is defined as the central axis C of the mounting portion 21 and the entire grommet 2, as shown in FIG.

[0016] 2, eight (plural) wire insertion holes 3, through which wires are inserted, are formed inside the wire insertion portion 20 and extend along the axial direction Y. The eight wire insertion holes 3 are independently formed inside the wire insertion portion 20.

[0017] Each of the eight wire insertion holes 3 is configured to penetrate from one end to the other end inside the wire insertion portion 20. As shown in Fig. 2, each wire insertion hole 3 is configured to have an opening 30 that opens in one end face 20f on one side of the wire insertion portion 20. Each opening 30 is formed to have a substantially circular shape when viewed from the front.

[0018] Each opening 30 is tapered so that its diameter gradually decreases from the outside toward the inside of each wire insertion hole 3. This makes it possible to easily insert the claws 10 (jig) of a diameter expander (described later) or an electric wire (not shown) into each opening 30 from the outside toward the inside of each wire insertion hole 3.

[0019] The inner diameter of each electric wire insertion hole 3 is set to be approximately equal to the outer diameter of the electric wire. With this setting, when the electric wire is inserted into the electric wire insertion hole 3, there is almost no gap between the electric wire and the electric wire insertion hole 3. This ensures an appropriate seal between the electric wire and the grommet 2 through which the electric wire is inserted.

[0020] As shown in FIG. 2, the eight wire insertion holes 3 are configured to include four inner insertion holes 3A opened in an inner region 20A (shown by a dotted line in FIG. 2) including the central axis C on one end face 20f of the wire insertion portion 20, which is substantially circular, and four outer insertion holes 3B formed in an outer region 20B separated from the central axis C by the inner region 20A.

[0021] 2, the four inner insertion holes 3A are opened at positions rotationally symmetrical with one another at 90 degrees with respect to the center (central axis C) of one end face 20f of the electric wire insertion portion 20. That is, the four inner insertion holes 3A are provided at equal intervals around the central axis C.

[0022] 2, the four outer insertion holes 3B are opened at positions rotationally symmetrical with respect to one another by 90 degrees with respect to the center C of one end face 20f of the wire insertion portion 20. That is, the four outer insertion holes 3B are provided at equal intervals around the central axis C. The outer insertion holes 3B and the inner insertion holes 3A are provided at positions shifted by 45 degrees from one another. That is, the outer insertion holes 3B and the inner insertion holes 3A are provided at positions shifted from one another in the radial direction of the wire insertion portion 20.

[0023] As shown in FIG. 1 , the mounting portion 21 includes an expanded diameter portion 21A continuous with the other end of the wire insertion portion 20, and a flange portion 21B continuous with the end of the expanded diameter portion 21A remote from the wire insertion portion 20. The expanded diameter portion 21A is formed in a tapered, hollow, generally truncated cone shape whose diameter gradually increases with increasing distance from the wire insertion portion 20. The flange portion 21B is formed in a generally cylindrical shape whose inner diameter is larger and generally constant than the outer diameter of the wire insertion portion 20. The internal spaces of the expanded diameter portion 21A and the flange portion 21B communicate with each other to form the internal space of the mounting portion 21. This internal space serves as a wire lead-out hole for leading an electric wire inserted into the grommet 2 through the wire insertion portion 20 to the outside of the grommet 2.

[0024] Such grommet 2 is attached to an object by fitting recess 21C formed between enlarged diameter portion 21A and flange portion 21B of mounting portion 21 into the inner edge of an attachment hole formed in the object (not shown). Therefore, when grommet 2 is attached to the object, wire insertion portion 20, enlarged diameter portion 21A of mounting portion 21, and flange portion 21B of mounting portion 21 are arranged in different spaces separated by a panel, partition wall, etc., with recess 21C as the boundary.

[0025] Next, a method for manufacturing the grommet-equipped electric wire will be described with reference to FIGS.

[0026] First, as shown in Fig. 3, the four claws 10 of the diameter expander are inserted into the respective openings 30 of the outer insertion holes 3B formed in one end face 20f of the wire insertion portion 20. Note that Fig. 4 shows only the four claws 10 of the diameter expander, and the illustration of the other parts is omitted.

[0027] Next, as indicated by the white arrows A1, A2, B1, and B2 in FIG. 3 , the claws 10 inserted into the respective outer insertion holes 3B are moved radially outward from the central axis C of the grommet 2 so as to separate from each other. That is, the diameters of the four outer insertion holes 3B are expanded in directions away from the central axis C (arrows A1, A2, B1, and B2). Specifically, the claws 10 inserted into the respective outer insertion holes 3B are moved in directions approximately 180 degrees opposite to each other along the directions indicated by the white arrows A1 and A2 in FIG. 3 . At the same time, the claws 10 are moved in directions approximately 180 degrees opposite to each other, indicated by the white arrows B1 and B2 in FIG. 3 . The directions indicated by the white arrows A1 and A2 and the directions indicated by the white arrows B1 and B2 are approximately perpendicular to each other.

[0028] Then, an external force is directly applied to each outer insertion hole 3B by each of the claws 10 inserted therein in the directions indicated by the white arrows A1, A2, B1, and B2 in Fig. 3. As a result, each outer insertion hole 3B and its opening 30 are stretched in the directions indicated by the white arrows A1, A2, B1, and B2 in Fig. 3.

[0029] Meanwhile, external forces are indirectly applied to the inner insertion holes 3A in the directions indicated by the white arrows A1, A2, B1, and B2 in FIG. 3 by the claws 10 inserted into the outer insertion holes 3B. That is, external forces are applied to the inner insertion holes 3A in two directions that are substantially perpendicular to each other. As a result, as shown in FIG. 4, the inner insertion holes 3A and their openings 30 are stretched in the directions indicated by the white arrows A1, A2, B1, and B2 in FIG. 4. In this way, the diameters of the openings 30 of the inner insertion holes 3A and the outer insertion holes 3B are expanded (insertion hole expanding process).

[0030] Next, the electric wire is inserted into the inside of each inner insertion hole 3A and each outer insertion hole 3B, the diameter of each opening 30 of which has been enlarged by each claw 10, through each opening 30 (electric wire insertion process). After this, the claws 10 inserted into the inside of each outer insertion hole 3B are removed from each outer insertion hole 3B. Each inner insertion hole 3A and each outer insertion hole 3B returns to its natural state. At this time, there is almost no gap between each electric wire insertion hole 3 and the electric wire. In this way, the manufacturing of the electric wire with a grommet is completed.

[0031] Thereafter, the electric wires inserted into the inner insertion holes 3A and the outer insertion holes 3B are fed into the electric wire guide holes through the other end sides of the electric wire insertion portions 20. The electric wires fed into the electric wire guide holes are fed out of the grommet 2 through the other end sides of the electric wire guide holes located at the other end of the grommet 2. Then, the electric wires that have been guided out of the grommet 2 are routed toward predetermined connection points (not shown) of the attachment object, and then connected to the connection points.

[0032] According to the above-described embodiment, the manufacturing method of a grommet-attached electric wire includes an insertion hole diameter expanding step of inserting the claws 10 (jigs) into four (plural) outer insertion holes 3B, respectively, and moving the claws 10 in directions (arrows A1, A2, B1, B2) away from the central axis C without inserting the claws 10 into the inner insertion hole 3A to expand the diameters of the four outer insertion holes 3B and the inner insertion holes 3A, and an electric wire insertion step of inserting electric wires into each of the four outer insertion holes 3B and the inner insertion holes 3A expanded in diameter in the insertion hole diameter expanding step. Thus, in the insertion hole diameter expanding step, the diameter of the inner insertion hole 3A is expanded as the diameter of each of the four outer insertion holes 3B is expanded. As a result, when the grommet 2 is configured to have at least one inner insertion hole 3A and a plurality of outer insertion holes 3B, the diameters of the inner insertion hole 3A and the outer insertion hole 3B can be expanded and electric wires can be inserted into the inner insertion hole 3A and the outer insertion hole 3B, respectively, without increasing the number of diameter expansion operations as in the conventional technology. This allows the insertion of electric wires into the electric wire insertion holes 3 with good workability. In other words, the workability when inserting electric wires into the grommet 2 can be improved.

[0033] Furthermore, four inner insertion holes 3A are provided at equal intervals around the central axis C, and four (plural) outer insertion holes 3B are provided at equal intervals around the central axis C, with the inner insertion holes 3A and the outer insertion holes 3B being offset in position in the radial direction of the electric wire insertion portion 20. This makes it possible to reduce the radial size of the electric wire insertion portion 20 and improve the workability when inserting an electric wire into the grommet 2, compared to when the inner insertion holes 3A and the outer insertion holes 3B are provided side by side in the radial direction of the electric wire insertion portion 20.

[0034] The present invention is not limited to the above-described embodiment, but includes other configurations that can achieve the object of the present invention, and the following modified examples are also included in the present invention.

[0035] In the above embodiment, the grommet 2 is configured to have four inner insertion holes 3A and four outer insertion holes 3B, but the present invention is not limited to this. The grommet may have one inner insertion hole 3A at a position overlapping the central axis C, or two or more inner insertion holes 3A arranged around the central axis C. Furthermore, the grommet may have five or more outer insertion holes 3B arranged around the central axis C.

[0036] In the above embodiment, the inner insertion hole 3A and the outer insertion hole 3B are provided at positions shifted in the radial direction of the electric wire insertion portion 20, but the present invention is not limited to this. The inner insertion hole 3A and the outer insertion hole 3B may be provided side by side in the radial direction of the electric wire insertion portion 20, although this will result in the electric wire insertion portion 20 becoming slightly larger in the radial direction.

[0037] Although the best configurations and methods for carrying out the present invention have been disclosed above, the present invention is not limited thereto. That is, although the present invention has been particularly illustrated and described mainly with reference to specific embodiments, those skilled in the art can make various modifications to the above-described embodiments in terms of shape, material, quantity, and other detailed configurations without departing from the scope of the technical idea and purpose of the present invention. Therefore, the above-disclosed descriptions limiting the shape, material, etc. are provided as examples to facilitate understanding of the present invention and are not intended to limit the present invention. Therefore, descriptions using names of components that are free from some or all of the limitations on shape, material, etc. are included in the present invention. [Explanation of symbols]

[0038] 2 grommets 20 Wire insertion part 20A inner area 3A Inner insertion hole 3B Multiple outer insertion holes 10 Jaws (jig) C center axis

Claims

1. A method for manufacturing a grommet-equipped electric wire, comprising: a grommet having an electric wire insertion portion for inserting an electric wire from one side to the other, the electric wire insertion portion being formed in a cylindrical shape with a central axis extending from the one side to the other; the grommet has at least one inner insertion hole provided in an inner region including the central axis of the electric wire insertion portion, and a plurality of outer insertion holes provided at positions spaced apart from the central axis across the inner region, an insertion hole diameter expanding step of inserting a jig into each of the plurality of outer insertion holes and moving the jig in a direction away from the central axis without inserting a jig into the inner insertion hole, thereby expanding diameters of the plurality of outer insertion holes and the inner insertion hole; and an electric wire insertion step of inserting the electric wire into each of the plurality of outer insertion holes and the inner insertion holes whose diameters have been expanded by the insertion hole diameter expanding step.

2. The inner insertion holes are provided in four pieces at equal intervals around the central axis, The plurality of outer insertion holes are four holes provided at equal intervals around the central axis, The method for manufacturing a grommet-equipped electric wire according to claim 1, wherein the inner insertion hole and the outer insertion hole are provided at positions shifted in a radial direction of the electric wire insertion portion.

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