JPH0312011Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a waterproofing section using a heat-shrinkable sleeve, such as at a connection section of an electric cable.

[Prior art]

For cable connections, etc., a method is used to create a waterproof structure by covering the entire connection with a heat-shrinkable sleeve and shrinking it. In this case, the end of the heat-shrinkable sleeve will be heat-shrinked onto the outer circumference of the cable to make a close contact with it, but it is difficult to achieve sufficient waterproofness with just this heat-shrinkable contact, so there is usually a gap between the heat-shrinkable sleeve and the cable. An adhesive layer is provided as a sealing material. An example is shown in FIG.

In the figure, 1 is a cable, 3 is a cable core connection part, 5 is a heat shrink sleeve, and 7 is an adhesive layer. In other words, this waterproof portion is obtained by providing an adhesive layer 7 of a required width around the outer periphery of the cable 1, covering the adhesive layer 7 with a heat-shrinkable sleeve 5, and heat-shrinking the adhesive layer 7. In this way, the adhesive layer 7 is compressed by the contraction force and seals the fine gaps, so that good waterproof properties can be obtained.

However, in the above-described structure, when the temperature of the cable increases due to energization or the like, internal pressure is applied to the adhesive layer, and this pressure may push the adhesive layer 7 outward, resulting in a decrease in waterproof performance. Further, when the heat-shrinkable sleeve is heat-shrinked, the heating flame also hits the outer periphery of the cable 1 near the end of the heat-shrinkable sleeve 5, so there is a risk of thermal deterioration of the cable. Particularly when the surface of the cable covered by the heat-shrinkable sleeve is an external semiconducting layer, a water-blocking layer, etc., its performance may be impaired by heat.

[Purpose of invention]

In view of the above problems, the purpose of this invention is to
To provide a waterproofing part for a cable that does not reduce waterproof performance and can prevent thermal deterioration of the cable when heat-shrinking a heat-shrinkable sleeve.

[Structure of the idea]

In order to achieve the above object, the present invention provides an adhesive layer of a required width around the outer periphery of a cable, covers the adhesive layer with a heat-shrinkable sleeve, and heat-shrinks the waterproof portion of the cable. A heat-insulating layer is provided on the outer periphery of the cable adjacent to the outer end, and the end of the heat-shrinkable sleeve is positioned on the heat-insulating layer.

〔Example〕

FIG. 2 shows an embodiment of the waterproofing section of the present invention. In this figure, parts corresponding to those in FIG. 1 are given the same reference numerals. Further, 1a is a cable sheath, 1b is an outer semiconducting layer, and 1c is a cable insulator. In this example, the outer semiconducting layer 1
An adhesive layer 7 is provided on the outer semiconducting layer 1b, and a heat insulating layer 9 is provided on the outer semiconducting layer 1b adjacent to the outer end of the adhesive layer 7. The heat insulating layer 9 is formed by winding and laminating a butyl rubber cloth tape on the outer semiconductive layer 1b. The heat-shrinkable sleeve 5 is heat-shrinked with its end positioned on the heat insulating layer 9.

In this way, when the heat-shrinkable sleeve 5 is heat-shrinked, the outer semiconductive layer 1b is not directly exposed to flame, so that thermal deterioration of the outer semiconductive layer 1b can be prevented. Also, the temperature of the cable increases and the adhesive layer 7
Even when the adhesive layer 7 is pressurized, the heat insulating layer 9 comes into contact with the outer end of the adhesive layer 7 and acts as a dam, thereby preventing the adhesive layer 7 from flowing and ensuring waterproof performance.

FIG. 3 shows an example of a cable connection section using the waterproofing section of the present invention. In this figure, parts corresponding to those in FIG. 2 are given the same reference numerals.
For this connection, an adhesive layer 11 is provided on the sheath 1a of the left cable, a second heat shrink sleeve 13 is placed from the sheath 1a to the left end of the heat shrink sleeve 5, and then An adhesive layer 15 is provided on the right end of the sleeve 13, an adhesive layer 17 is provided on the right cable sheath 1a, and a third heat-shrinkable sleeve 19 is placed over both. In addition, this connection part is a plug-in type prefabricated connection part, 21 is a compressed connection sleeve of a conductor, 23 is a spacer having a semiconductive layer 25 on the outer end, and 27 is an internal conductive layer 29 on the inner peripheral surface.
3, an insulating cylinder having an outer conductive layer 31 on its outer peripheral surface;
3 is a conductive member that brings the compression connection sleeve 21 and the internal conductive layer 29 to the same potential.

Although the above embodiment describes the waterproofing section of a power cable, the present invention can also be applied to communication cables and optical cables.

[Effect of idea]

As explained above, according to the present invention, the heat insulating layer is provided adjacent to the outer end of the adhesive layer provided on the outer periphery of the cable, so even if the adhesive layer is pressurized due to thermal expansion of the cable, the heat insulating layer remains intact. It acts as a dam and can prevent the adhesive layer from flowing outward. Therefore, deterioration in waterproof performance can be prevented. Furthermore, since the end of the heat-shrinkable sleeve is located on the heat-insulating layer, the outer periphery of the cable is not directly exposed to flame during heat-shrinking work, which has the advantage of preventing thermal deterioration of the cable.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an example of a conventional waterproofing section, Fig. 2 is a sectional view showing an embodiment of the waterproofing section of the present invention, and Fig. 3 is a cable connection using the waterproofing section of the present invention. It is a sectional view showing an example of a part. 1a... Cable sheath, 1b... External semiconductive layer, 1c... Cable insulator, 3... Cable core connection portion, 5... Heat shrink sleeve, 7... Adhesive layer, 9... Heat insulation layer.

Claims (1)

[Scope of utility model registration request] An adhesive layer of a required width is provided around the outer circumference of the cable, and a heat-shrinkable sleeve is placed to cover the adhesive layer.In the waterproofing part of the cable, the outer circumference of the cable is placed adjacent to the outer end of the adhesive layer. A waterproofing section for a cable, characterized in that a heat-insulating layer is provided on the cable, and an end portion of the heat-shrinkable sleeve is positioned on the heat-insulating layer.