JPH04363882A - Watertight processing method for cable connecting part - Google Patents

Abstract

PURPOSE:To sufficiently make a transverse stress work, enhance the press contact by a press with a low pressurizing force, and improve sealing property by covering a cable connecting part with an adhesive seal material, and pressurizing the connecting part with a press mold having a pressurizing surface having a protrudingly curved cross section. CONSTITUTION:A cable connecting part B and cables mutually extended are placed on the adhesive sealing agent layer 2 of a sheet seal material A, the connecting metal fitting 3 of the connecting part B is positioned in the center of the layer, and the connecting part B is enclosed by the seal material A and set in upper and lower dies 21, 22 of a press mold. This press mold has a protrudingly curved cross section, and a transverse stress generated because of the circular pressurizing surface is added to the seal agent under pressurization, in addition to the transverse stress based on the Poisson's ratio transverse deflection. Thus, the transverse stress is sufficiently worked by the press with a low pressurizing force to enhance the press contact, and the sealing property is enhanced.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for water-tightening electric wire connections, particularly electric wire branch connections, using a viscous sealing material.

0002

2. Description of the Related Art Watertight treatment of electric wire connections is essential from the standpoint of insulating the electric wire connections and preventing corrosion.

Traditionally, a method of wrapping self-adhesive tape has been used to make electrical wire connections watertight, but this requires a considerable amount of effort and time, and is especially difficult for complicated corners. In the case of existing branch connections, it is extremely difficult to completely fill the corner locations, and watertightness is also a problem.

[0004]Recently, in order to eliminate such problems,
A sheet-like sealing material A' having a viscous sealant layer 2' on one side of a sheet-like support material 1' as shown in (a) of FIG. As shown in FIG.
As shown in c), a method of applying pressure using press molds 21' and 22' has been proposed.

In this method, a viscous sealant is press-fitted into the corner of the wire connection location by pressurization, filling the corner and imparting sealing properties. Therefore, generating sufficient internal pressure in the viscous sealant is an important requirement for imparting sealing properties.

[0006]

[Problems to be Solved by the Invention] The above-mentioned viscous sealant uses a viscoelastic material whose main component is uncrosslinked rubber, such as uncrosslinked butyl rubber, and has properties intermediate between an elastic material and a fluid. As for the internal pressure generated in the viscous sealant by the above-mentioned pressurization, it is necessary to take into account the stress caused by the elastic body in addition to the pressure transmission as a fluid.

[0007] In the above, stress generated in the viscous sealant in a direction perpendicular to the direction of press pressure is also closely related to the seal as elastic body stress due to press pressure, and this lateral stress It is also effective to increase the sealing performance.

However, in (c) of FIG. 4, the lateral stress generated due to the elastic properties of the viscous sealant 2' is the Poisson's ratio tensile stress generated due to the compressive strain in the thickness direction of the press pressure P'. There is only a lateral stress P'' based on strain, and in order to increase this lateral stress P'', it is necessary to increase the press pressure considerably.

However, if the press force is too high,
There are concerns that the sealant may protrude from both lengthwise ends of the sheet-like sealant coated on the wire connection part, and that the sheet-like support material may be pierced by the wire connection fittings. There is a limit to the increase in pressurizing force.

An object of the present invention is to use a sheet-like sealant having a viscous sealant layer on one side of a sheet-like support as a viscous sealant.
When coating electrical wire connections with the sealing agent layer on the inside and applying pressure to this coating using a press mold to make the electrical wire connections watertight, the viscous sealant can be applied even under relatively low pressing pressure. The purpose is to apply sufficient directional stress (pressure) to strengthen the lateral pressure contact between the sealant and the surface to be sealed (the side surface of the wire, the side surface of the wire connection fitting).

[0011]

[Means for Solving the Problems] The watertight treatment method for electric wire connections of the present invention involves applying a sheet-like sealing material provided with a viscous sealant layer on one side of a sheet-like support material to electric wire connections. In a method in which a viscous sealant layer is applied to the electrical wire connection part facing inward, and the coated sealant is pressed by a press die, the pressure is applied to a pressure surface having a convex curved cross section. This configuration is characterized in that it is carried out using a press mold having.

0012

[Function] Since the pressing surface of the press mold is a curved surface with a convex cross section, the pressing surface is an arcuate surface in addition to the lateral stress caused by Poisson's ratio lateral strain on the viscous sealant under press pressure. As a result, the lateral stress (lateral pressure) generated by the press can be increased compared to when the pressing surface is flat, and the viscous sealing from the lateral direction to the surface to be sealed can be increased.
It can strengthen the pressure welding of the adhesive.

[0013]

[Embodiments] Hereinafter, embodiments of the present invention will be explained with reference to the drawings. Figure 1(a) shows the sheet-like sheet used in the present invention.
In this figure, a viscous sealant 2 (a viscous sealant 2 that can maintain adhesiveness and self-shape retention even at high temperatures) is applied to one side of a sheet-like support material 1 (for example, a plastic film such as a vinyl chloride film). An elastic material (for example, a composition containing uncrosslinked butyl rubber as a main component) is formed into a layer, and a position mark 20 such as a groove is attached to the center of the viscous sealant layer 2. The thickness of the layer is set to be 1/3 or more of the electric wire.

FIG. 1B shows a press mold used in the present invention, in which a groove 210 having a concave cross section (for example,
A lower mold 21 having a circular arc groove) and a protrusion 2 having a convex curved cross section
20, and the arcuate diameter of the groove 210 is larger than the arcuate diameter of the protrusion 220.

In order to make the electric wire connection part watertight according to the present invention, the electric wire connection part B is placed on the viscous sealant layer 2 of the sheet-like sealant A as shown in FIG. , the wires are spaced apart, and the connecting fitting 3 of the wire connecting portion B is positioned in the center of the viscous sealant layer 2, and further, as shown in FIG.
As shown in (b), the sheet-shaped sealing material A is bent to surround the wire connection portion B with the sheet-shaped sealing material A. Next, as shown in FIG.
The sheet-like sealing material A is placed in between the two ends of the sheet-like supporting material a, a, which are held between the flat parts of the upper and lower molds 21 and 22, and in this state, the viscous sealing material is Pressure 2. The pressing force at this time may be approximately 10.5 kg/cm2 or less. In FIG. 2C, the curvature of the convex portion of the upper mold 22 is larger than the curvature of the groove of the lower mold 21.

Due to this pressing, lateral stress based on Poisson's ratio lateral tensile strain acts on the viscous sealant 2, and since the pressing surface is a curved surface, as shown in FIG. 3(d), A component force ΔP acts between two points separated by a small angle Δθ,
This force also applies pressure to the viscous sealant 2 in the lateral direction. Therefore, compared to when the press pressing surface is a flat surface,
Even under the same press pressure, the lateral press force on the viscous sealant can be increased by making the press press surface an arcuate surface.
Accordingly, the pressure contact between the surface to be sealed (the side surface of the electric wire, the side surface of the electric wire connection fitting) and the viscous sealant from the lateral direction can be strengthened.

According to the watertight treatment method for electric wire joints of the present invention, the viscous sealant flows in the lateral direction (width direction) of the electric wire joints due to pressurization, and the viscous sealant increases as it reaches both ends. -The amount of drug used increases. Therefore, as shown in FIG. The thickness of the adhesive can be made thicker, and the insulation properties can be strengthened.
This is advantageous in reliably preventing the sheet-like support material from being penetrated by the electric wire connection fitting during pressurization.

Furthermore, as shown in FIG. 3, if a notch 23 is provided in the press mold and the wire connection fitting is released into this notch during press pressurization to create a non-pressurized state, the surroundings of the wire connection fitting can be removed. The viscous sealant can be encouraged to spread around the viscous sealant, which is even more advantageous.

In the above, an upper mold (lower mold) having a protrusion with a convex curve in cross section is used, and a flexible material such as rubber is used for the lower (upper) mold, or a concave curve in cross section. It is also possible to use an upper mold (lower mold) having grooves, and use a flexible material such as rubber for the lower (upper) mold.

[0020] In the above, after pressing, the sheet
Adhesive tape may be wrapped around the outside of the material, or it may be used as is without wrapping.

[0021]

[Effects of the Invention] The watertight treatment method for electric wire connections according to the present invention has the above-mentioned configuration, and since the pressurizing surface of the press mold is a curved surface, the viscous sealing material can be subjected to lateral strain based on Poisson's ratio lateral strain. Not only pressure, but also lateral force due to the curved pressing surface can be applied, and the lateral pressing force can be larger than when the pressing surface of the press mold is a flat surface. It is possible to strengthen the lateral pressure contact between the sealant and the surface to be sealed, which is advantageous in improving sealing performance.

[0022] Furthermore, since the entire electric wire connection part can be easily bent in two in cross section to reduce its apparent shape, electric wires having the electric wire connection part treated according to the present invention can be easily bundled. The tape can also be easily wrapped around the wire connection portion.

[Brief explanation of drawings]

FIG. 1(A) is an explanatory view showing a sheet-shaped sealing material used in the present invention, and FIG. 1(B) is an explanatory view showing a press mold used in the present invention.

FIG. 2 is an explanatory diagram showing the working procedure of the embodiment of the present invention.

FIG. 3 is an explanatory diagram showing another example of the press mold used in the present invention.

FIG. 4 is an explanatory diagram showing a conventional example.

[Explanation of symbols]

1 Sheet-shaped support material 2 Viscous sealant A Sheet-shaped sealing material 21 Lower mold 22 Upper mold

Claims (2)

[Claims] Claim 1: Wire connection using a sheet-shaped sealing material provided with a viscous sealant layer on one side of a sheet-shaped support material on the wire connection portion with the viscous sealant layer facing inside. A method of applying pressure to a wire connection part using a press die and applying pressure to the coated sealing material using a press die, the above-mentioned pressurizing being carried out using a press die having a pressure surface having a convex curved cross section. Watertight treatment method. [Claim 2] A press mold is used in which one of the upper and lower press molds is provided with a pressure surface having a convex curved cross section, and the other press mold is provided with a pressure surface having a concave curved cross section. Watertight treatment method for electrical wire connections as described.