JP3444466B2 - Jig for expanding rubber insulator unit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diameter-expanding jig for a rubber insulator unit in forming a plug-in type connection portion of a rubber or plastic power cable such as a CV cable.

[0002]

2. Description of the Related Art FIG. 3 is a longitudinal sectional view of a main portion of a plug-in type connecting portion of a rubber or plastic power cable. In the drawing, 11 is an insulating core of a cable having a plastic insulating layer such as cross-linked polyethylene, 12 is a connecting portion of a cable conductor, 13 is a rubber insulator unit, and a semiconductive rubber member is provided on an inner peripheral portion of the insulating rubber portion 13A. The outer periphery of the inner electrode 13B is integrally formed with the outer semiconductive layer 13 of semiconductive rubber, and the inner diameter thereof is smaller than the outer diameter of the insulating core 11. In the rubber insulator unit 13, the internal electrode 13B may be integrally molded in advance on the inner peripheral portion of the insulating rubber portion 13A, and then the outer semiconductive layer 13C may be formed on the outer peripheral portion of the insulating rubber portion 13A.

In forming the connecting portion, a pipe-shaped expanding jig having an inner diameter larger than the outer diameter of the cable is inserted into the inner diameter portion of the rubber insulator unit 13 to expand the diameter, and then the cable conductor is connected. The rubber insulation unit 13 is inserted in advance on one of the cables in advance, and after the cable conductor is connected, the rubber insulation unit 13 is returned to the conductor connection portion 12 and the expansion jig is pulled out to make the rubber insulation unit 13 self-contractile. By the above, the insulating core 11 is closely attached and mounted to form a connecting portion insulating portion.

[0004]

In the above case, the diameter-expanding jig usually uses a single pipe, and after the conductor is connected, the rubber insulator unit in which the diameter-expanding jig is inserted is returned to the conductor connecting portion and expanded. Since the diameter jig is pulled out, the diameter expansion jig needs to be cut and removed. For this reason, it is necessary to use a new diametrical expansion jig each time the connection portion is formed, which is expensive and takes a lot of time. In addition, the insertion and removal of the diameter expansion jig expands the inner diameter of the rubber insulator unit to around 200%.
An insertion force and a withdrawal force of around 1000 kgf were required.

In order to solve the above-mentioned problems, the diameter-expanding jig is made of a strong material that can withstand the above-mentioned insertion force and withdrawal force,
In order to reduce the pulling-out force, a method has been proposed in which a diameter-expanding jig divided in the central portion in the direction orthogonal to the axis is used to pull out on both sides. Further, a method has been proposed in which a groove is provided in the end surface of the diameter expanding jig in consideration of the drawing work, and the drawing jig is attached to the groove to easily draw the groove. Further, in order to save the cutting time after drawing, it has been proposed to divide the diametrical expansion jig in the longitudinal direction and remove it without cutting. However, when the diameter-expanding jig is divided in the direction orthogonal to the axis and the longitudinal direction, a structure capable of withstanding the insertion force at the time of insertion becomes necessary.

[0006]

SUMMARY OF THE INVENTION The present invention provides a diameter-expanding jig for a rubber insulator unit that solves the above-mentioned problems, and is characterized by the direction in which one pipe is orthogonal to the axis of the pipe. And in the longitudinal direction, the seams of the pieces divided in the longitudinal direction are displaced in the circumferential direction, and further, the mating parts of the pipes, which are divided in the direction orthogonal to the axis, are aligned. It may be connected in the longitudinal direction via an engaging portion provided in the portion.

[0007]

1 is an external view of a specific example of a diameter-expanding jig of the present invention. The one pipe that makes up the diameter expansion jig is
It is divided into two pipes 1 and 2 in a direction orthogonal to the pipe axis at a substantially central portion in the longitudinal direction. The pipes 1 and 2 divided into two parts are further divided into two parts in the longitudinal direction of the pipe, and are composed of pieces 1A and 1B and pieces 2A and 2B. And the seam 4 and the piece 2 of the pieces 1A and 1B described above.
The seams 5 of A and 2B are displaced in the circumferential direction as shown in the figure.

Further, the mating portion 3 of the two pipes 1 and 2 divided into two in the direction orthogonal to the axis of the pipe is provided in the mating portion 3 as shown in FIGS. 2A and 2B. They are connected via a joint. That is, in FIG. 2A, for example, one pipe 1 of the mating portion 3 is provided with a concave portion 3a, and the other pipe 2 is provided with a convex portion 3b, and the concave portion 3a and the convex portion 3b are fitted and connected. ing. As another means, step portions 3C and 3d are provided at the joining portion 3 of the pipes 1 and 2, and the step portions 3C and 3d are provided.
Are engaged and connected.

[0009]

As described above, according to the diameter-expanding jig of the present invention, the seam of each piece divided in the longitudinal direction of the pipe is shifted in the circumferential direction, so that when the rubber unit is inserted. The cut surface in the longitudinal direction is apparently eliminated, and the insertion force similar to that of a single product can be obtained without buckling or the like. Also, by connecting the mating parts of the two pipes, which are divided in two in the direction orthogonal to the axis of the pipes, through the engaging parts, it is possible to prevent the axial separation and to damage the rubber insulator unit during insertion. There is nothing.

[Brief description of drawings]

FIG. 1 is an external view of a specific example of a diameter expanding jig of the present invention.

FIG. 2A and FIG. 2B are explanatory views of a mating portion of two pipes which are divided into two in a direction orthogonal to the pipe axis.

FIG. 3 is a vertical cross-sectional view of a main part of a plug-in connection portion of a rubber / plastic power cable.

[Explanation of symbols]

1, 2 Two pipes 1A, 1B, 2A, 2B divided into two in the direction orthogonal to the axis Each piece of the pipe 3 divided in the longitudinal direction 3 Mating part

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Claims (2)

(57) [Claims] 1. A a first pipe, a second pipe connectable to the longitudinal direction and the first pipe
And the first pipe and the second pipe are divided in the longitudinal direction.
And a second pipe , which is formed by combining two pieces, which form the first pipe.
So that the seams of the pieces that form
A jig for expanding the diameter of a rubber insulator unit, which is characterized by being connected to . 2. At the joining portion of the first pipe and the second pipe
The rubber insulator unit according to claim 1 , wherein the first pipe and the second pipe are connected to each other in the longitudinal direction via the engaging portion. Expanding jig.