Waterproof structure

Abstract

To provide a waterproof structure that suppresses leakage of hot melt material to the outside even when the temperature of the environment using a cable rises.SOLUTION: A waterproof structure 100 includes a first heat-shrinkable tube 2 covering the outer periphery of a plurality of cables 1, which shrinks when heated, a hot melt material 3 provided between the cables 1 and the first heat-shrinkable tube 2, and a second heat-shrinkable tube 4 provided on the outer periphery of the first heat-shrinkable tube 2, which shrinks when heated so that both ends (ends 4a, 4b) come into close contact with the outer peripheral surface of the cable 1.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a waterproof structure. [Background technology]

[0002] Patent Document 1 discloses an invention of a waterproof structure that is configured to eliminate gaps between electrical wires by heating a hot melt material to melt it and allow the hot melt material to penetrate between multiple electrical wires. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-224961 Summary of the Invention [Problem to be solved by the invention]

[0004] In the invention described in Patent Document 1, if the temperature of the environment in which the electric wires are used becomes high, the hot melt material that has permeated between the electric wires may melt and leak out. If the hot melt material leaks out in this way, it may drip onto other parts or devices, affecting their operation.

[0005] The present invention has been made in consideration of the above problems, and aims to provide a waterproof structure that can prevent hot melt material from leaking to the outside even if the temperature of the environment in which the cable is used rises. [Means for solving the problem]

[0006] The present invention is a waterproof structure that prevents water from entering between multiple cables, and is characterized by comprising a first heat-shrinkable tube that covers the outer periphery of the multiple cables and shrinks when heated, a hot-melt material that is provided between the multiple cables and the first heat-shrinkable tube, and a second heat-shrinkable tube that is provided on the outer periphery of the first heat-shrinkable tube and shrinks when heated so that both ends thereof come into close contact with the outer periphery of the multiple cables.

[0007] In this invention, the second heat-shrinkable tube is arranged on the outside of the first heat-shrinkable tube and so that both ends are in close contact with the outer surfaces of multiple cables. Therefore, even if the temperature of the environment in which the cables are used rises and the hot-melt material melts, the hot-melt material can be prevented from leaking out from the second heat-shrinkable tube.

[0008] Furthermore, the present invention is characterized in that a space is provided between both end faces of the first heat-shrinkable tube and the second heat-shrinkable tube in the axial direction.

[0009] In this invention, a space is provided between both end faces of the first heat-shrinkable tube and the second heat-shrinkable tube in the axial direction, so that the hot-melt material can be retained in this space when it melts, thereby more reliably preventing the hot-melt material from leaking out.

[0010] In addition, the present invention is characterized in that the thickness of the second heat-shrinkable tube is greater than the thickness of the first heat-shrinkable tube.

[0011] In this invention, the thickness of the second heat-shrinkable tube is greater than the thickness of the first heat-shrinkable tube, so that the outer shape of the waterproof structure can be maintained even if an external force is applied from the radial outside of the second heat-shrinkable tube. [Effects of the Invention]

[0012] According to the present invention, even if the temperature of the environment in which the cable is used rises, leakage of the hot melt material to the outside can be suppressed. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is an external view of a waterproof structure according to an embodiment of the present invention when used together with a cable gland. [Figure 2] FIG. 2 is an exploded view of the waterproof structure and cable gland according to the embodiment of the present invention. [Figure 3] FIG. 3 is a cross-sectional view of the waterproof structure according to the embodiment of the present invention taken along an axial direction. [Figure 4] FIG. 4 is a cross-sectional view of the waterproof structure according to the embodiment of the present invention taken along line IV-IV in FIG. [Figure 5] FIG. 5 is a diagram for explaining the procedure for assembling the waterproof structure according to the embodiment of the present invention. [Figure 6] FIG. 6 is a cross-sectional view of the waterproof structure according to the embodiment of the present invention taken along line VI-VI in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0015] 1, the waterproof structure 100 in this embodiment is used to prevent water from entering between the gaps between multiple cables 1. Specifically, the waterproof structure 100 is used to prevent water from entering into the housing 20 between the outer surfaces of the multiple cables 1 connected to an electrical device (not shown) housed in the housing 20 and a cable gland 10 attached to the housing 20, or through gaps between the multiple cables 1. Note that the cable 1 in this embodiment mainly refers to a cable in which a sheath (protective outer coating) is applied to each insulated electric wire whose conductor is insulated, but also refers to a cable used for optical or communication purposes or a cable in which the conductor is covered with a protective coating made of an insulator.

[0016] First, the configuration of a cable gland 10 to which a waterproof structure 100 is applied will be briefly described with reference to Figures 1 and 2. Figure 1 is an external view of the waterproof structure 100 and the cable gland 10, and Figure 2 is an exploded view of the waterproof structure 100 and the cable gland 10.

[0017] The cable gland 10 includes a connector 11 having a first male thread portion 11a and a second male thread portion 11b, a rubber bushing 12 provided between the inner surface of the first male thread portion 11a and the outer surface of the waterproof structure 100 (second heat-shrinkable tube 4), a cap 13 screwed onto the first male thread portion 11a, and a lock nut 14 screwed onto the second male thread portion 11b.

[0018] The connector 11 has a main body 11c, and the first male threaded portion 11a and the second male threaded portion 11b are provided on opposite sides in the axial direction with the main body 11c sandwiched therebetween.

[0019] The first externally threaded portion 11a is provided with a slit (not shown) extending in the axial direction, and is reduced in diameter by tightening a cap 13 having an internal thread formed on its inner circumferential surface.

[0020] The second male thread portion 11b is inserted into a through hole 20a provided in the housing 20. The connector 11 is fixed to the housing 20 by threading the lock nut 14 onto the second male thread portion 11b with the second male thread portion 11b inserted into the through hole 20a of the housing 20.

[0021] The rubber bushing 12 is a cylindrical rubber member. The waterproof structure 100 attached to the cable 1 is inserted into the through-hole of the rubber bushing 12 inserted into the inside of the first male thread portion 11a, and the waterproof structure 100 is sealed between the inner peripheral surface of the first male thread portion 11a and the outer peripheral surface of the waterproof structure 100 by tightening the cap 13.

[0022] Next, the waterproof structure 100 will be described with reference to FIGS.

[0023] The waterproof structure 100 includes a first heat-shrinkable tube 2 that covers the outer periphery of the cable 1 and shrinks when heated, a hot-melt material 3 that is provided between the cable 1 and the first heat-shrinkable tube 2, and a second heat-shrinkable tube 4 that is provided around the outer periphery of the first heat-shrinkable tube 2 and shrinks when heated, so that both ends (ends 4a, 4b) come into close contact with the outer periphery of the cable 1. Specific materials for the hot-melt material 3 include, for example, EVA-based (ethylene vinyl acetate, softening point approximately 80°C to 110°C), PO (polyolefin)-based (softening point approximately 100°C to 150°C), ACR (acrylic)-based (softening point approximately 90°C), and PA (polyamide)-based (softening point approximately 150°C). Hereinafter, the waterproof structure 100 and the area of ​​the cable 1 protected by the waterproof structure 100 will be collectively referred to as the "protected portion P."

[0024] The first heat-shrinkable tube 2 and the second heat-shrinkable tube 4 are cylindrical tubes with a circular cross section (see FIG. 4, etc.). There are no particular restrictions on the material of the first heat-shrinkable tube 2 and the second heat-shrinkable tube 4, but they may be made of, for example, a thermoplastic elastomer, polyolefin, or fluorine-based polymer. The first heat-shrinkable tube 2 and the second heat-shrinkable tube 4 may be made of the same material or different materials. In this embodiment, the thickness of the first heat-shrinkable tube 2 is, for example, about 0.5 mm, and the thickness of the second heat-shrinkable tube 4 is, for example, about 0.5 mm to 1.2 mm. The first heat-shrinkable tube 2 and the second heat-shrinkable tube 4 are made of tubes with a shrinkage temperature slightly higher than the softening point of the hot-melt material 3.

[0025] 2 and other figures, the axial length of the second heat-shrinkable tube 4 is longer than the axial length of the first heat-shrinkable tube 2. Specifically, the axial length of the second heat-shrinkable tube 4 is set to a length that allows both end portions 4a, 4b of the second heat-shrinkable tube 4 to be in close contact with the outer peripheral surface of the cable 1 when the first heat-shrinkable tube 2 and the second heat-shrinkable tube 4 are shrunk, and also to a length that allows a space S to be provided between the end faces 2a, 2b of the first heat-shrinkable tube 2 and the end portions 4a, 4b of the second heat-shrinkable tube 4 in the axial direction. The space S in this embodiment has, for example, an inner diameter of 3 mm, an outer diameter of 4 mm, a width of 0.5 mm, and a volume of 2.7 mm. 3 It is formed in a ring shape.

[0026] Furthermore, in this embodiment, the thickness of the second heat-shrinkable tube 4 is greater than the thickness of the first heat-shrinkable tube 2. By making the second heat-shrinkable tube 4 thicker, it is possible to prevent deformation of the protective portion P due to radially inward pressing force caused by compression of the rubber bushing 12 when the cap 13 is tightened. Furthermore, by preventing deformation in this way, it is possible to more reliably maintain the sealing performance between the rubber bushing 12 and the protective portion P (second heat-shrinkable tube 4).

[0027] The hot melt material 3 is applied in advance to the inner peripheral surface of the first heat shrink tube 2 and is formed integrally with the first heat shrink tube 2. By preparing such a heat shrink tube in which the first heat shrink tube 2 and the hot melt material 3 are integrated as a long tube wound on a reel, for example, it can be cut to the desired length as needed for use, thereby improving work efficiency.

[0028] Next, a method for manufacturing the waterproof structure 100 will be described with reference to FIGS.

[0029] First, multiple cables 1 are inserted into a first heat-shrinkable tube 2 (hot-melt material 3) (see FIG. 5(A)). Next, the outer surface of the first heat-shrinkable tube 2 is heated using a dryer or the like. The first heat-shrinkable tube 2 shrinks when heated. This narrows the gaps between the multiple cables 1 and the gaps between the cables 1 and the first heat-shrinkable tube 2. The heat from the dryer also melts the hot-melt material 3, which then flows into the gaps between the multiple cables 1 (see FIG. 5(B)). In this way, the first heat-shrinkable tube 2 shrinks while the hot-melt material 3 melts, so that the molten hot-melt material 3 fills the gaps between the multiple cables 1 and the gaps between the outer surface of the cables 1 and the first heat-shrinkable tube 2 without leaving any gaps (see FIG. 5(B)).

[0030] Next, the second heat-shrinkable tube 4 is placed so as to cover the outer periphery of the first heat-shrinkable tube 2 (see FIG. 5(C)). Then, the outer periphery of the second heat-shrinkable tube 4 is heated using a dryer or the like. This causes the second heat-shrinkable tube 4 to shrink and come into close contact with the outer periphery of the first heat-shrinkable tube 2 (see FIGS. 3 and 4). At this time, both ends 4a, 4b of the second heat-shrinkable tube 4 are brought into close contact with the outer periphery of the multiple cables 1 (see FIG. 3).

[0031] As described above, in the waterproof structure 100 of this embodiment, both end portions 4a, 4b of the second heat-shrinkable tube 4 are in close contact with the outer peripheral surface of the cable 1, and the hot melt material 3 is filled in the gaps between the multiple cables 1 and the gaps between the outer peripheral surfaces of the cables 1 and the first heat-shrinkable tube 2. This makes it possible to prevent water from entering the housing 20 through the gaps between the cables 1 or along the outer peripheral surface of the cables 1.

[0032] Furthermore, if the environment in which the cable 1 is used becomes hot, there is a risk that the hot melt material 3 of the protective portion P will melt. In this case, the molten hot melt material 3 will be pushed out of the first heat-shrinkable tube 2 by the radially inward pressing force caused by the compression of the rubber bushing 12 of the cable gland 10, and will flow to the outside of the first heat-shrinkable tube 2. However, in the waterproof structure 100 of this embodiment, the second heat-shrinkable tube 4 is provided on the outside of the first heat-shrinkable tube 2 so that both ends 4a, 4b of the second heat-shrinkable tube 4 are in close contact with the outer peripheral surface of the cable 1. This allows the second heat-shrinkable tube 4 to prevent the molten hot melt material 3 from leaking to the outside.

[0033] Furthermore, in the waterproof structure 100 of this embodiment, a space S is provided between the end faces 2a, 2b of the first heat-shrinkable tube 2 and the end faces 4a, 4b of the second heat-shrinkable tube 4 in the axial direction, so that the hot melt material 3 that flows out from the first heat-shrinkable tube 2 can be stored in the second heat-shrinkable tube 4. Gaps may remain between multiple cables 1 near both ends 4a, 4b of the second heat-shrinkable tube 4 (see FIG. 6 ). However, by providing the space S as in the waterproof structure 100 of this embodiment, the flowing hot melt material 3 can be retained within the space S. This prevents the molten hot melt material 3 from reaching both ends 4a, 4b of the second heat-shrinkable tube 4, and more reliably prevents the molten hot melt material 3 from leaking to the outside.

[0034] Furthermore, in the waterproof structure 100 of this embodiment, even if the molten hot melt material 3 is pushed out from the end faces 2a and 2b of the first heat shrinkable tube 2 by the pressing force of the rubber bushing 12, the pushed out hot melt material 3 pushes out the second heat shrinkable tube 4 from the inside. As a result, the space S expands (in this embodiment, 2 mm 3 This makes it possible to store a larger amount of hot melt material 3. This makes it possible to more reliably prevent the hot melt material 3 from leaking out of the second heat-shrinkable tube 4.

[0035] In the above embodiment, the case where there are two cables 1 has been described as an example, but the number of cables 1 is not limited to this. The number of cables 1 may be three or more.

[0036] In the above embodiment, the waterproof structure 100 and the cable gland 10 are used together and applied to the location where the cable 1 passes through the housing 20, but this is not limiting. For example, the waterproof structure 100 alone may be used to ensure waterproofness at the connection portion where the cables 1 are connected to each other.

[0037] The configuration, operation, and effects of the embodiment of the present invention configured as above will be described below.

[0038] The waterproof structure 100 comprises a first heat-shrinkable tube 2 that covers the outer periphery of the cable 1 and shrinks when heated, a hot melt material 3 that is provided between the cable 1 and the first heat-shrinkable tube 2, and a second heat-shrinkable tube 4 that is provided on the outer periphery of the first heat-shrinkable tube 2 and shrinks when heated so that both ends (ends 4a, 4b) come into close contact with the outer periphery of the cable 1.

[0039] In this configuration, the second heat-shrinkable tube 4 is arranged on the outside of the first heat-shrinkable tube 2, and both ends (ends 4a, 4b) are in close contact with the outer surface of the cable 1. Therefore, even if the temperature of the environment in which the cable 1 is used rises and the hot melt material 3 melts, the hot melt material 3 can be prevented from leaking out from the second heat-shrinkable tube 4.

[0040] In the waterproof structure 100, a space S is provided between the second heat-shrinkable tube 4 and both end surfaces 2a, 2b of the first heat-shrinkable tube 2 in the axial direction.

[0041] In this configuration, a space S is provided between both end surfaces 2a, 2b of the first heat-shrinkable tube 2 and the second heat-shrinkable tube 4 in the axial direction, so that when the hot-melt material 3 melts, the hot-melt material 3 can be retained in this space S. This more reliably prevents the molten hot-melt material 3 from leaking out.

[0042] In the waterproof structure 100, the thickness of the second heat-shrinkable tube 4 is greater than the thickness of the first heat-shrinkable tube 2.

[0043] In this configuration, the thickness of the second heat-shrinkable tube 4 is greater than the thickness of the first heat-shrinkable tube 2, so that the external shape of the waterproof structure 100 can be maintained even if an external force is applied from the radial outside of the second heat-shrinkable tube 4.

[0044] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0045] In the above embodiment, the cable 1 has been described as an example, but it is of course possible to apply the present invention to an electric wire.

[0046] Furthermore, in the above embodiment, the first heat-shrinkable tube 2 and the hot melt material 3 are integrally formed, but they may be formed as separate bodies.

[0047] Furthermore, in the above embodiment, an example in which the space S is provided has been described, but the space S may be provided only on one side in the axial direction, or the space S may not be provided at all.

[0048] Furthermore, the thickness of the first heat-shrinkable tube 2 and the thickness of the second heat-shrinkable tube 4 may be the same as long as the rigidity of the second heat-shrinkable tube 4 is ensured, or the thickness of the first heat-shrinkable tube 2 may be thicker.

[0049] In the above embodiment, the second heat-shrinkable tube 4 is described as being made up of a single tube, but this is not limiting, and the second heat-shrinkable tube 4 may be made up of a double heat-shrinkable tube. [Explanation of symbols]

[0050] 100 Waterproof structure, 1 Cable, 2 First heat shrink tube, 3 Hot melt material, 4 Second heat shrink tube, 4a End, 4b End, 10 Cable gland, 20 Housing, 21 Through hole, P Protective part, S Space

Claims

1. A waterproof structure that prevents water from entering between multiple cables, a first heat-shrinkable tube that covers the outer periphery of the plurality of cables and shrinks when heated; a hot melt material provided between the cables and the first heat shrinkable tube; A waterproof structure characterized by comprising a second heat-shrinkable tube that is provided around the outer periphery of the first heat-shrinkable tube and shrinks when heated so that both ends thereof come into close contact with the outer periphery of the plurality of cables.

2. The waterproof structure according to claim 1, A waterproof structure, characterized in that a space is provided between both end faces of the first heat-shrinkable tube and the second heat-shrinkable tube in the axial direction.

3. The waterproof structure according to claim 1 or 2, A waterproof structure, characterized in that the thickness of the second heat-shrinkable tube is thicker than the thickness of the first heat-shrinkable tube.

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