Manufacturing method of electric wire provided 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 an electric wire with a grommet. [Background technology]

[0002] Conventionally, in order to protect a wire harness passing through an opening provided 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 penetrating therethrough for inserting each of a plurality of electric wires.

[0004] When inserting an electric wire into an electric wire insertion hole provided in such a conventional grommet, a tool called a diameter expander that expands the diameter of each electric wire insertion hole is generally used. The diameter expander has a portion called a claw that is inserted into the electric wire insertion hole. The claw of the diameter expander is inserted into the electric wire insertion hole of the grommet and moved toward the outside in the radial direction of the electric wire insertion hole. This expands the diameter of the electric wire insertion hole, making it possible to easily insert the electric wire into the expanded electric wire insertion hole. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-230065 A 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 outwardly 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. For this reason, for example, in the case of a grommet 102 shown in Fig. 5, in which a group of electric wire insertion holes 120 having four electric wire insertion holes 103, two vertically and two horizontally, are arranged side by side, 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 an electric wire with a grommet, which improves the workability when inserting an electric wire into a grommet. [Means for solving the problem]

[0008] In order to solve the above problem 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 having 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 moving the jig in a direction away from the central axis without inserting the jig into the inner insertion hole, thereby expanding 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 expanded by the insertion hole expanding step. Effect 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 description of the drawings]

[0010] [Figure 1] FIG. 2 is a perspective view showing a grommet constituting the manufacturing method for an electric wire with a grommet according to an embodiment of the present invention. [Diagram 2] FIG. [Diagram 3] FIG. 13 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. [Figure 4] 4 is a diagram showing a step subsequent to that shown in FIG. 3, showing a state in which the outer insertion holes and the inner insertion holes have been enlarged in diameter. FIG. [Diagram 5] FIG. 1 is a plan view showing a conventional grommet. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, a method for manufacturing an electric wire with a grommet according to one embodiment of the present invention will be described with reference to Figs. 1 to 4. Fig. 1 is a perspective view showing a grommet 2 constituting a manufacturing method for an electric wire with a grommet 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 manufacturing method for an electric wire with a grommet, 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 constituting the manufacturing method for an electric wire with a grommet in this embodiment is configured to allow an electric wire (not shown) to 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 purposes of waterproofing, dustproofing, and soundproofing the attachment hole.

[0013] As shown in FIGS. 1 and 2, grommet 2 is integrally provided with electric wire insertion portion 20 through which an electric wire is inserted, and mounting portion 21 which can be fitted into a mounting hole provided in an object to be mounted (not shown).

[0014] The electric 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 electric wire insertion portion 20, and the electric wire is guided and held in the axial direction Y (one direction).

[0015] 1, the axial direction Y of the electric wire insertion portion 20 is defined as the axial direction Y of the entire grommet 2. The radial direction of the electric wire insertion portion 20 perpendicular to the axial direction Y (longitudinal direction) of the electric 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 electric 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, inside the electric wire insertion portion 20, eight (plural) electric wire insertion holes 3 are formed extending along the axial direction Y, through which the electric wires are inserted. The eight electric wire insertion holes 3 are formed independently inside the electric wire insertion portion 20.

[0017] Each of the eight electric wire insertion holes 3 is configured to penetrate from one end to the other end inside the electric wire insertion portion 20. As shown in Fig. 2, each of the electric wire insertion holes 3 is configured to have an opening 30 that opens in one end face 20f on one side of the electric 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 to the inside of each electric wire insertion hole 3. This makes it possible to easily insert the jaws 10 (jig) of a diameter expander (described later) and an electric wire (not shown) into each opening 30 from the outside to the inside of each electric 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 away from the central axis C, sandwiching the inner region 20A.

[0021] 2, the four inner insertion holes 3A are opened at positions rotationally symmetrical with respect to one another by 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 that are rotationally symmetrical with respect to each other by 90 degrees with respect to the center C of one end face 20f of the electric 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 from each other by 45 degrees. That is, the outer insertion holes 3B and the inner insertion holes 3A are provided at positions shifted from each other in the radial direction of the electric wire insertion portion 20.

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

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

[0025] Next, a method for manufacturing the electric wire with a grommet 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 inside of each outer insertion hole 3B one by one into each opening 30 of each outer insertion hole 3B opened in one end face 20f of the electric wire insertion portion 20. Note that Fig. 4 shows only the four claws 10 of the diameter expander, and the illustration of other parts is omitted.

[0027] Next, as shown by the white arrows A1, A2, B1, and B2 in FIG. 3, the claws 10 inserted into the outer insertion holes 3B are moved away from each other in the radial direction outward from the central axis C of the grommet 2. That is, the four outer insertion holes 3B are expanded in the direction away from the central axis C (arrows A1, A2, B1, and B2). Specifically, the claws 10 inserted into the outer insertion holes 3B are moved in the directions shown by the white arrows A1 and A2 in FIG. 3 in the opposite directions by about 180 degrees. At the same time, the claws 10 are moved in the directions shown by the white arrows B1 and B2 in FIG. 3 in the opposite directions by about 180 degrees. The directions shown by the white arrows A1 and A2 and the directions shown 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 in the directions indicated by the white arrows A1, A2, B1, and B2 in Fig. 3 by each of the claws 10 inserted therein, so that 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] On the other hand, an external force is indirectly applied to each inner insertion hole 3A in the directions indicated by the white arrows A1, A2, B1, and B2 in FIG. 3 by each of the claws 10 inserted into each of the outer insertion holes 3B. That is, an external force is applied to each inner insertion hole 3A in two directions that are substantially perpendicular to each other. As a result, as shown in FIG. 4, each inner insertion hole 3A and its opening 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 each inner insertion hole 3A and each opening 30 of each outer insertion hole 3B are expanded (insertion hole diameter expanding process).

[0030] Next, the electric wire is inserted through each opening 30 into the inside of each inner insertion hole 3A and each outer insertion hole 3B whose diameter has been enlarged by each claw 10 (electric wire insertion process). After this, the claw 10 inserted into the inside of each outer insertion hole 3B is 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 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 hole through the other end side of each electric wire insertion portion 20. Each electric wire fed into the electric wire guide hole is guided out of the grommet 2 through the other end side of the electric wire guide hole located at the other end of the grommet 2. Then, each electric wire guided out of the grommet 2 is routed toward a predetermined connection point of the attachment object (not shown), and then connected to the connection point.

[0032] According to the above-mentioned embodiment, the manufacturing method of the grommet-attached electric wire includes an insertion hole expanding step of inserting the claws 10 (jigs) into the four (plural) outer insertion holes 3B and moving the claws 10 in the direction (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 hole 3A, and an electric wire insertion step of inserting electric wires into the four outer insertion holes 3B and the inner insertion hole 3A expanded in the insertion hole expanding step. According to this, in the insertion hole expanding step, the diameter of the inner insertion hole 3A is expanded in accordance with the expansion of the diameters of the four outer insertion holes 3B. As a result, when the grommet 2 is configured to have at least one inner insertion hole 3A and multiple outer insertion holes 3B, the inner insertion hole 3A and the outer insertion hole 3B can be expanded in diameter, and the electric wire can be inserted into each of the inner insertion hole 3A and the outer insertion hole 3B, without increasing the number of times of diameter expansion work as in the conventional technology. This allows the insertion of the electric wire into the electric wire insertion hole 3 with good workability. In other words, the workability when inserting the electric wire into the grommet 2 can be improved.

[0033] Further, 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 provided at shifted positions in the radial direction of the electric wire insertion portion 20. With this, compared to a case in which 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, it is possible to reduce the radial size of the electric wire insertion portion 20 and improve the workability when inserting the electric wire into the grommet 2.

[0034] It should be noted that 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 embodiment, the grommet 2 is configured to have four inner through-holes 3A and four outer through-holes 3B, but the present invention is not limited to this. The grommet may have one inner through-hole 3A at a position overlapping with the central axis C, or may have two or more inner through-holes 3A arranged around the central axis C. The grommet may also have five or more outer through-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 different positions 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 a slight increase in the radial size of the electric wire insertion portion 20.

[0037] In addition, the best configurations and methods for implementing the present invention are disclosed in the above description, but the present invention is not limited thereto. That is, the present invention has been mainly illustrated and described with reference to specific embodiments, but 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 descriptions limiting the shapes, materials, etc. disclosed above are illustrative descriptions for the purpose of facilitating understanding of the present invention, and do not limit the present invention, and therefore descriptions of the names of components that are free of some or all of the limitations on the shapes, materials, 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 through holes 10 Jig (jig) C center axis

Claims

1. A method for manufacturing a grommet-attached electric wire, comprising: a grommet having an electric wire insertion portion for inserting an electric wire from one side to the other side, the electric wire insertion portion being formed in a cylindrical shape having a central axis extending from the one side to the other side, the grommet including the electric wire being inserted into the grommet, 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 away 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 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 numbers at equal intervals around the central axis, The plurality of outer insertion holes are provided at four locations at equal intervals around the central axis, The method for manufacturing an electric wire with a grommet according to claim 1 , wherein the inner insertion hole and the outer insertion hole are provided at different positions in a radial direction of the electric wire insertion portion.

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