JP2008078017A - Interline water cutoff structure for wire harness, and water cutoff material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an interline water cutoff structure for a wire harness capable of responding to the changes in the environmental conditions, and of exhibiting full water cutoff performance, and to provide a water cutoff material. <P>SOLUTION: When a foaming gas that is the content of a microcapsule 36 is dispersed in a vessel by influence under a heating environment, the internal pressure of the vessel of the microcapsule 36 will increase. As a result, the contracted vessel will expand, whereby seal in a state where certain stress is applied thereto can be provided, and adhesion of a wire 37 to this water cutoff material 27 will be improved. Accordingly, high water cutoff performance can be obtained. Even if the water cutoff material 27 is in a cold environment, the microcapsule 36 will absorb expansion/contraction due to the influence under the environment, separation of the wire 37 from the water cutoff material 27 can be suppressed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wire harness inter-water waterproof structure formed by water-stopping a wire harness using a water-stop material, and a water-stop material suitable for the line water-stop structure.

  Reference numeral 1 in FIG. 5 indicates, for example, a grommet disclosed as a conventional example in Patent Document 1 below. The grommet 1 is a so-called water stop grommet, and has a cylindrical insertion tube 3 at the small-diameter side end of a funnel-shaped grommet body 2. A wire harness 4 is inserted through the insertion tube 3. A part of the insertion tube 3 extends to the inside of the grommet body 2, and a water stop pot 5 for storing a water stop material is coupled to the extended end.

  The water stop pot 5 is disposed and formed inside the grommet body 2. Further, the water stop pot 5 is disposed and formed so as to have an appropriate interval with respect to the inner surface of the grommet body 2. Such a water stop pot 5 is filled with a water stop material 6. The space between the trunk lines of the wire harness 4 inserted through the grommet 1 is sealed with a cured water-stop material 6. As the water blocking material 6, a two-component polyurethane resin adhesive is used. In the figure, it is assumed that the portion filled with the water stop material 6 forms a line water stop structure of the wire harness 4.

In addition, in Patent Document 1 below, in order to reduce the weight of the water-stopping material, a foam material that is independently foamed by ultraviolet irradiation or heating is mixed with the water-stopping material, and the water-stopping material is cured in a substantially sponge shape. Examples are also disclosed. In the case of this example, since the amount of the water-stopping material is reduced by at least the amount foamed to become a cavity, there is an advantage that the weight of the water-stopping material can be reduced as a result.
JP 2005-80428 A

  Use of liquid rubber (liquid silicone rubber or the like) as a sealing material such as the water blocking material 6 is conceivable. However, it is known that liquid rubber itself has poor adhesiveness with PVC or polyolefin resin wire coatings. The inventor of the present application conducts a thermal shock test in an example using such a liquid rubber, and there is a possibility that a gap due to peeling may be generated between the electric wire (wire coating) and the water stop material from this test. Heading. Therefore, when liquid rubber is used, there is a problem that it is necessary to fully consider the influence of changes in environmental conditions.

  In order to avoid the generation of gaps due to peeling, it is conceivable that the wire harness is previously subjected to primer treatment or a tackifier component is added to the liquid rubber. However, in the former case, there is a problem that the work man-hours are increased and the working environment is deteriorated due to the use of a solvent, and in the latter case, the cost of the tackifying component is considerable, so the use of this tackifying component greatly increases the cost. There is a problem that it increases.

  The present invention has been made in view of the above-described circumstances, and is capable of responding to changes in environmental conditions, and is capable of sufficiently exhibiting water-stopping performance. It is an issue to provide.

  In order to solve the above-mentioned problems, the wire harness line water stop structure according to claim 1 of the present invention is formed by water stopping between the wires of the wire harness using a water stop material. In the structure, liquid rubber is used as the water-stopping material, and an additive for the water-stopping material is characterized by adding a microcapsule in which a container that has been shrunk until then is expanded under a heating environment. .

  According to a second aspect of the present invention, in the wire harness line water-stop structure according to the first aspect of the present invention, the microcapsule can be contracted and expanded in a cold environment. It is said.

  According to a third aspect of the present invention, in the wire harness line water-stop structure according to the first or second aspect of the present invention, the amount of the microcapsule added is 2 wt% to 6 wt%. It is characterized by that.

  The water-stopping material of the present invention according to claim 4, which has been made to solve the above-mentioned problems, is obtained by adding to the liquid rubber as an additive a microcapsule in which a container that has been shrunk until then increases in an internal pressure in a heating environment. It is characterized by becoming.

  According to the present invention having such a feature, when the portion of the water stop structure that stops water between the wires of the wire harness is placed in a heating environment, in other words, a container of microcapsules added to the water stop material and When the contents are affected by the heating environment, the microcapsules act on the surroundings as follows. For example, when the content of the microcapsule is a foaming gas, the foaming gas is diffused to increase the internal pressure of the container. When the internal pressure of the container rises, the container is brought into a swelled state from the contracted state, and as a result, the water stop material itself of the microcapsule acts to press the electric wire. Thereby, since an electric wire and a water stop material will be in the state which mutually adheres, water stop performance is fully ensured. According to the present invention, even in a cold environment, the microcapsule acts to absorb surrounding shrinkage and expansion according to the environment, so that the separation between the electric wire and the water stop material is suppressed.

  According to the line waterstop structure of the present invention described in claim 1, the waterstop formed by adding to the liquid rubber as an additive a microcapsule in which the internal pressure rises in a heating environment and the container that has shrunk until then expands. Since the material is used, there is an effect that it can sufficiently cope with a change in the environmental state. In addition, there is an effect that water stopping performance can be sufficiently exhibited.

  According to the line water stop structure of the present invention described in claim 2, there is an effect that the surrounding expansion and contraction can be absorbed according to the change of the environmental state. Therefore, the water stop performance can be improved as compared with the prior art.

  According to the line waterstop structure of the present invention described in claim 3, as one of the ranges in which the sealing pressure is improved, the addition amount of the microcapsule is set to 2 wt% to 6 wt%, thereby improving the water stop performance. There is an effect that it can be used as a guideline for improvement.

  According to the waterstop material of the present invention described in claim 4, as in claim 1, there is an effect that it is possible to sufficiently cope with a change in environmental state. In addition, there is an effect that water stopping performance can be sufficiently exhibited.

  Hereinafter, description will be given with reference to the drawings. FIG. 1 is a cross-sectional view showing an embodiment of a water-stopping structure between wire harness lines and a water-stopping material of the present invention, (a) is a view showing a state before foaming, and (b) is foaming in a heating environment. It is a figure which shows the state after having performed. Moreover, FIG. 2 is a state explanatory view of the wire harness line water-stop structure and the water-stop material, (a) shows a state before foaming, and (b) shows a state after foaming in a heating environment. FIG. 3 is an explanatory view showing a state in which expansion and contraction is absorbed during cooling, and FIG. 4 is a view showing airtightness after a thermal shock test.

  In FIG.1 and FIG.2, the reference number 21 has shown the water stop grommet. This water stop grommet 21 has elasticity made of rubber or elastomer, and for example, seals between the panel hole formed through the vehicle panel and the wire harness 22 inserted through the panel hole, sound insulation, And is provided for electrical insulation. The water stop grommet 21 includes a small diameter insertion tube (clamping portion) 23, a large diameter grommet main body 24 coupled to one end of the insertion tube 23, and a water stop pot coupled to the other end of the insertion tube 23. 25. The main line portion 26 of the wire harness 22 is sealed between wires (between wires) by a water stop material 27 according to the present invention cured in the water stop pot 25.

  The insertion cylinder 23 is formed in a cylindrical shape by the peripheral wall 28 so that the trunk portion 26 of the wire harness 22 can be inserted. The insertion cylinder 23 is formed so as to have a slightly smaller diameter than the trunk portion 26 of the wire harness 22 to be inserted. Such an insertion tube 23 is formed so as to be able to hold the trunk portion 26 of the wire harness 22. The length of the insertion tube 23 in the grommet axial direction is set to an appropriate length here as long as the wire harness 22 can be fixed.

  The grommet main body 24 has a panel fitting portion 29 and a through hole 30. The panel fitting portion 29 is a portion formed outside the grommet body 24 and has an annular groove 31, an inclined portion 32, and a thick portion 33. The panel fitting part 29 is formed over the entire circumference in the grommet circumferential direction.

  The water stop pot 25 is formed in a substantially cup shape. Moreover, the water stop pot 25 is formed so that the water stop material 27 which concerns on this invention can be collected. A through hole that is continuous with the inner surface of the insertion tube 23 is formed at the bottom of the water stop pot 25. The trunk portion 26 of the wire harness 22 is inserted through the through hole.

  The length of the water stop pot 25 in the grommet axial direction is appropriately formed in consideration of the amount of the water stop material 27 stored. Moreover, the diameter of the water stop pot 25 is formed to a diameter that can pass through the panel hole when the water stop grommet 21 is attached (exaggeratedly large in the drawing). The part of the water stop pot 25 in a state where the water stop material 27 is accumulated and hardened is an essential part of the water stop structure 34 between the wire harness lines according to the present invention.

  The water stop material 27 according to the present invention includes a liquid rubber 35 and microcapsules 36 added to the liquid rubber 35. For example, the liquid rubber 35 is a moisture-curing liquid silicone rubber (for example, manufactured by Toray Dow Corning, whose name is a one-component reaction type RTV rubber), and is preferably cured without heating. The microcapsule 36 includes a polymer container (microcontainer) and contents filled in the container, and a microcapsule having a size of 20 μm is used here (microcapsule). The size of 36 is an example, and the amount added will be described later). For example, foam gas is applied to the contents. Here, the contents are not particularly limited as long as they can be diffused in the container under the influence of the heating environment and the internal pressure can be increased.

  The microcapsule 36 is such that the internal pressure rises in a heating environment and the container that has shrunk until then expands. Moreover, the microcapsule 36 can be contracted and expanded in a cold environment. In other words, the microcapsule 36 is a foamed microcapsule. In the case of FIGS. 1 (a) and 2 (a), the microcapsule 36 is not expanded, and in the heating environment of FIGS. 1 (b) and 2 (b). Each foamed microcapsule is shown.

  In the water stop pot 25, the water stop material 27 is cured after entering the periphery of the trunk portion 26 of the inserted wire harness 22 and the gaps between the electric wires 37 constituting the wire harness 22, thereby forming the water stop portion. It comes to form. The electric wire 37 and the water stop material 27 form a close contact state.

  Next, the process of forming the wire harness line water stop structure 34 according to the present invention and the operation after mounting on the vehicle will be described based on the above configuration.

  The wire harness line water stop structure 34 is formed through a process of inserting the water stop grommet 21 into the trunk portion 26 of the wire harness 22, a process of preparing the water stop material 27, and a process of performing a water stop process. . When the water stop grommet 21 is inserted through the trunk portion 26 of the wire harness 22, the trunk portion 26 of the wire harness 22 is held by the insertion cylinder 23. The water blocking material 27 is prepared by adding an appropriate amount of microcapsules 36 to the liquid rubber 35 and stirring. When the water-stopping material 27 is stored in the water-stopping pot 25 to perform the water-stopping treatment, in this embodiment, the water-stopping material 27 is composed of a moisture-curable liquid silicone rubber as the liquid rubber 35 constituting the water-stopping material 27. It cures without heating. When the water stop material 27 is cured, a water stop structure 34 between the wire harness lines is thereby formed (see FIGS. 1A and 2A).

  In order to mount the water stop grommet 21 in which the wire harness inter-wire stop structure 34 is formed on the vehicle, it is necessary to fit it in the panel hole of the vehicle. Although not particularly illustrated, first, the water stop pot 25 to the insertion cylinder 23 are inserted into the panel hole, and the insertion cylinder 23 is pulled together with the wire harness 22 from the opposite side of the insertion side. When the insertion tube 23 is pulled together with the wire harness 22, the inclined portion 32 comes into contact with the panel hole, and elastic deformation occurs in the inclined portion 32 due to this contact. Thereby, the inclined portion 32 is reduced in diameter, and when the reduced inclined portion 32 passes through the panel hole while sliding, the annular groove 31 is fitted into the panel hole. When the annular groove 31 is completely fitted into the panel hole, the installation work of the water stop grommet 21 is completed (in addition, after the work of attaching the water stop grommet 21, the step of performing the water stop treatment may be performed). To do).

  After the vehicle is mounted, if the foaming gas that is the contents of the microcapsule 36 is diffused in the container due to the influence of the heating environment, the internal pressure of the microcapsule 36 increases. Thereby, since the container which has shrunk swells, a seal in a state where a certain stress is applied is obtained, and the adhesion (pressure) between the electric wire 37 and the water stop material 27 is improved (FIG. 1B and FIG. 2 (b)). Therefore, high water stopping performance is obtained. Even if the water stop material 27 is in a cold environment, the microcapsule 36 absorbs the expansion and contraction (see FIG. 3) due to the influence of this environment, so that the separation between the electric wire 37 and the water stop material 27 is suppressed. .

  As described above with reference to FIG. 1 to FIG. 3, the present invention is the wire harness line-to-wire waterproofing structure 34 and the water-stopping material 27 that can improve the water-stopping performance as compared with the prior art.

  As other effects, the present invention eliminates the need for applying a primer treatment to the electric wire or adding a tackifying component to the liquid rubber. In addition, since there is no need to perform primer treatment on the electric wires, man-hours can be reduced. Moreover, since the solvent is not used, the invention can be made friendly to the working environment. Moreover, the cost of adding a tackifier component can be reduced. Further, since the microcapsule 36 has a hollow shape, the weight can be reduced.

  FIG. 4 is a diagram showing the airtightness after the thermal shock test (−40 ° C. to 120 ° C .: 100 cycles). Judging from the results obtained by the thermal shock test, it can be said that the addition amount of the microcapsule 36 is 2 wt% (weight percent) to 6 wt% (preferably 4 wt% to 6 wt%, or 5 wt% to 6 wt%). ).

  In addition, it goes without saying that the present invention can be variously modified without departing from the spirit of the present invention.

It is sectional drawing which shows one Embodiment of the water stop structure between wire harness lines of this invention, and a water stop material, (a) is a figure which shows the state before foaming, (b) after foaming in a heating environment It is a figure which shows a state. It is a state explanatory view of a wire harness line water stop structure and a water stop material, (a) is a diagram showing a state before foaming, (b) is a diagram showing a state after foaming in a heating environment is there. It is. It is explanatory drawing of the state which absorbs expansion-contraction at the time of cold heat. It is a figure which shows the airtightness after a thermal shock test. It is sectional drawing which shows the water stop structure between wire harness lines of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 21 Water stop grommet 22 Wire harness 23 Insertion pipe 24 Grommet main body 25 Water stop pot 26 Trunk part 27 Water stop material 28 Peripheral wall 29 Panel fitting part 30 Through-hole 31 Circular groove 32 Inclined part 33 Thick part 34 Wire harness line stop Water structure 35 Liquid rubber 36 Microcapsule 37 Electric wire

Claims (4)

In the wire harness inter-water waterproof structure formed by water-stopping between the wires of the wire harness using a water-stop material,
A wire harness wire characterized by using liquid rubber as the water-stopping material, and adding as the water-stopping material a microcapsule in which an internal pressure rises in a heating environment and a container that has shrunk until then expands Intermittent water structure. In the water stop structure between wire harness lines according to claim 1,
The microcapsule is capable of contracting and expanding in a cold environment. In the water stop structure between wire harness lines according to claim 1 or 2,
The addition amount of the microcapsules is 2 wt% to 6 wt%. A water-stopping material characterized in that a microcapsule in which a container that has been shrunk until then is expanded under a heating environment is added to liquid rubber as an additive.

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