JPH06233440A - Connection box for power cable - Google Patents

Abstract

PURPOSE:To determine easily the compression extent of a premolded insulator, by providing a pipe-like guide stopper comprising a middle core and an outer cylinder on the outside of the several springs of a premolded-insulator compressing device. CONSTITUTION:On the outside of several springs 20 of a premolded-insulator compressing device 22, a guide stopper 30 is provided. In the compression state of the premolded-insulator compressing device 22, the device 22 is contracted by it being so slit that an outer cylinder 33 is lifted by a pressing hardware 22 to the height equal to the bottom of a middle core 31. At this time, the length of the guide stopper 30 is made equal to a spring length L1. Also, in the final setting state of the device 22, the position of the upper end of the outer cylinder 33 becomes the position wherein the upper end is contacted with a stopper 33 of the middle core 31. At this time, the length of the guide stopper 30 is so formed as to be equal to an optimum spring length L2. Therefore, without any dimensional measurement, the automatic and proper setting of the spring dimension is made possible, and its workability can be improved largely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a junction box for a plastic power cable, and more particularly to improvement of a compression device for premolded insulators.

[0002]

2. Description of the Related Art The construction of a conventional plastic power cable junction box will be described with reference to the drawings. FIG. 4 is a cross-sectional view showing the structure of a plastic power cable connection box mounted on a mounting wall of a power device via an intermediate flange, and FIG. 5 is an enlarged cross-sectional view of the premolded insulator compression device portion thereof.
That is, the connection box 10 includes the upper metal part 11 and the conductor pulling rod 12
An epoxy porcelain tube 13 having a tip is fixed to a mounting wall 14 of a power device via an intermediate flange 15. A cable 16 whose tip is stepped off is inserted into the epoxy porcelain tube 13, and a cable conductor 16a at the tip is inserted into the conductor pulling rod 12
Connect to. Then, the premolded insulator 17 fitted to the outer circumference of the insulator of the cable 16 is inserted into the tapered surface provided on the inner surface of the epoxy porcelain tube 13, and the back of this is provided on the mounting plate 19 via the intermediate flange 15 and the insulating cylinder 18. In addition, the pre-molded insulator compression device 22 including the shaft 25, the pressing metal fitting 26, the spring 20 and the pressing member 21 is used to press-fit the electric field to relax the electric field. The premolded insulator compression device 22 adjusted in this way is covered with a protective metal fitting 23 on the outside, and a waterproof layer 24 is formed with a waterproof tape to shield it.

Next, the premolded insulator compressing device 2 for the plastic power cable connection box constructed as described above.
The adjustment procedure of No. 2 will be described. First, the premold insulator 17 is placed by the premold insulator compressing device 22 set to a constant length L ₀ so as to be in contact with the tapered surface of the epoxy porcelain tube 13. After that, the nut 27 of the shaft 25 is tightened to push up the push fitting 21 so that the spring length L ₁ is reached, and the premold insulator 17 is strongly pressed. By measuring the spring set length L ₁ at this time, it is confirmed that an appropriate pressure is transmitted to the premolded insulator 17. Then, after maintaining this state for a certain period of time, the final spring set length L ₂
Adjust while setting the nut 27 of the shaft 25 while loosening it. And at this time, the proper spring set length L
That it is ₂ to confirm by measuring the spring lengths. In this way, the spring set length was changed to three lobes and the spring set dimension was measured twice in the circumferential direction to perform assembly and adjustment, which was very troublesome.

By the way, the cable 16 repeatedly expands and contracts due to thermal expansion during energization, and the premolded insulator 17 also expands and contracts accordingly. In this state, an appropriate pressure is always transmitted to the interface between the taper surface of the epoxy porcelain tube 13 and the premold insulator 17, so that the spring length of the spring 20 of the premold insulator compressing device 22 can be changed to about ± 3 mm. Must have become.

[0005]

As described above, in the power cable junction box, the spring 20 of the premold insulator compressing device 22 is used to transmit an appropriate pressure to the interface between the epoxy porcelain tube 13 and the premold insulator 17. Must be set to an appropriate length. At this time, in order to ensure the operation of the premolded insulator compression device 22, it is necessary to measure the spring length at several points in the circumferential direction with a gauge. In addition, this work includes pre-compression in which pressure is once applied with a pressure larger than the normal pressure in order to improve the adhesiveness of the interface between the epoxy porcelain tube 13 and the pre-mold insulator 17.
It is necessary to measure the positions of several points in the circumferential direction twice in total when the pressure is set to the normal pressure. Also, if the dimensions of the spring are incorrect, the electrical performance will deteriorate.

The present invention solves the above-mentioned drawbacks of the prior art, and the spring can be set to a length for applying an appropriate pressure to the premold insulator without measuring the spring length of the premold insulator compression device. An object of the present invention is to provide a power cable connection box.

[0007]

In a prefabricated type connection box for connecting a power cable, a center core and an outer cylinder are provided outside a plurality of springs of a premold insulator compression device for crimping a premold insulator to an epoxy porcelain tube. A pre-molded insulator compression device is configured by providing a tubular guide stopper made of.

[0008]

Since a guide stopper having a simple structure is provided outside the spring at several places of the premolded insulator compression device, the spring can be set to an appropriate length without measuring the spring length when setting the spring twice. In this way, the assembly workability can be greatly improved.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing the configuration of a power cable junction box of the embodiment, FIG. 2 is an enlarged cross-sectional view of a premolded insulator compression device portion of the power cable junction box, FIG.
(B) is a front view and a side view of the guide stopper. The same members as those of the conventional connection box will be described with the same reference numerals. That is, the connection box 10a is the mounting wall 14 for the power equipment.
An epoxy porcelain tube 13 is fixed to the via an intermediate flange 15. A conductor lead-out rod 12 is fixed to an upper portion of the epoxy porcelain bushing 13 by an upper metal fitting 11, and a cable conductor 16a at a tip of a cable 16 having a stepped end is connected to the conductor lead-out rod 12 through the epoxy porcelain bushing 13. . Then, the shaft 25, the pressing metal fitting 26, the spring 20 and the pressing member in which the pre-molded insulator 17 previously inserted into the cable 16 from the lower side of the taper surface in the epoxy porcelain tube 13 is attached to the intermediate flange 15 by the attaching plate 19, Premold insulator compression device 22 comprising 21
It is configured to be pressed and pressed to relax the electric field.

The pre-molded insulator compressing device 22 has a plurality of springs 20 outside the spring 20 shown in FIG.
A guide stopper 30 as shown in (B) is provided. That is, the guide stopper 30 is a tubular center core 31.
And an outer cylinder 33 having a flange bent inward at an upper portion fitted to the outside of the bottom of the inner core 31 so as to be slidable up and down.
A protruding stopper 32 is provided on the outer side of the.
Therefore, when the pre-molded insulator compression device 22 shown in FIG.
And then slide to reduce the height to the same height as the bottom of the core 31. At this time, the length of the guide stopper 30 becomes the spring length L ₁ . In the state shown in FIG. 3B at the final setting, the outer cylinder 33 extends downward due to its own weight, and the upper end of the outer cylinder 33 comes into contact with the stopper 33 of the core 31. Stopper 30
Is designed to have an optimum spring length L ₂ .

Next, the junction box 10a thus constructed.
The assembly adjustment of will be described. First, the tip of the cable 16 connected to the conductor pull-out rod 12 on the upper portion of the epoxy porcelain tube 13 is stripped off to expose the cable conductor 16a, and this is connected. Then, the pre-molded insulator 17 previously inserted in the cable 16 is moved to the upper part, and the shaft 25, the pressing metal fitting 26, the spring provided on the mounting plate 19 from the back portion through the intermediate flange 15 and the insulating cylinder 18 are pressed. 20. Pre-molded insulator compressing device 22 comprising 20 and pressing member 21
Then, the upper surface of the pre-molded insulator 17 is pressed against the taper surface of the inner surface of the epoxy porcelain tube 13 by pressing.

At this time, the premolded insulator compression device 2
As shown in the enlarged view of FIG. 2, 2 is a core 20 and an outer cylinder 32, which are located outside the springs 20 provided at a plurality of positions in the circumferential direction, for example, at three places at intervals of 120 °. A configured guide stopper 30 is provided.
Therefore, in the state of pressurization and compression in which the nut 27 is tightened to raise the pressing member 26, the guide stopper 30 is minimized and the spring length of the spring 20 is set to L ₁ as shown in FIG. 3 (A). It Further, when the nut 27 is loosened and the metal fitting 26 is lowered, the guide stopper 30 becomes the maximum length as shown in FIG.
At this time, the spring 20 is adjusted to the optimum spring length L ₂ .

In the assembly adjustment, the nut 2 of the shaft 25 is first pressed during the pre-compression in which the pre-mold insulator compressing device 22 is first strongly pressed against the pre-mold insulator 17.
7 is tightened, and the spring 20 is compressed to the state of the spring length L ₁ where the length of the guide stopper 30 becomes the minimum,
The premolded insulator 17 is strong and surely press-bonds to the tapered surface of the inner surface of the epoxy porcelain tube 13. After maintaining this state for a certain period of time, the nut 27 is then attached to the guide stopper 3
Optimal spring length L ₂ by loosening to the longest position of 0
Set it to. Therefore, the degree of tightening can be known only by tightening or loosening the nut 27 without needing a scale or the like, so that the spring 20 of the premolded insulator compression device 22 can be easily assembled to a predetermined size. it can.

The guide stopper 30 for the spring set must be strong enough to withstand mechanical pressure during pre-setting and final setting, and is formed of an iron pipe or the like. Further, when the spring is set to the regular size, it should not interfere with the movement of the spring of ± 2 to 3 mm.
The slide between the outer tube 32 and the outer tube 32 must be formed so as to move smoothly.

In the above example, the guide stopper in the case of vertical assembly is explained, but in the case of horizontal assembly, the outer cylinder 3 is used.
Since 2 does not fall down by its own weight, the inner core 31 and the outer cylinder 32
A mechanism may be provided in which a spring is inserted between and the outer cylinder 32 is pushed out. The spring force at this time must not hinder the spring force of the junction box body. Further, the power cable junction box of the present invention can be applied not only to the power cable terminal connection portion but also to the device intermediate connection portion or the device direct connection portion.

[0016]

As described above, in the electric power cable junction box of the present invention, by simply providing the pre-molded insulator compression device with a simple guide stopper, in the assembly of the conventional junction box, the spring set dimension is extended twice. It is possible to automatically set the proper spring set size without measuring the size of the work that has been measured and assembled, and the workability can be greatly improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a power cable junction box of an embodiment,

FIG. 2 is an enlarged cross-sectional view showing the configuration of a premolded insulator compression device for the power cable junction box of FIG.

3 (A) and 3 (B) are side views showing a state of the guide stopper at the time of compression and compression and a state at the time of final setting,

FIG. 4 is a cross-sectional view showing the configuration of a conventional power cable junction box,

5 is an enlarged cross-sectional view showing the configuration of a premolded insulator compression device for the power cable junction box of FIG.

[Explanation of symbols]

 10, 10a Power cable connection box 12 Conductor lead-out rod 13 Epoxy porcelain tube 15 Intermediate flange 16 Cable 16a Cable conductor 17 Premold insulator 19 Mounting plate 20 Spring 21 Pressing member 22 Premold insulator Compressor 30 Guide stopper 31 Center core 32 Stopper 33 outer cylinder

Claims (1)

[Claims] 1. A prefabricated connection box for connecting a power cable, comprising a tubular core consisting of a core and an outer cylinder outside a plurality of springs of a premold insulator compression device for crimping a premold insulator to an epoxy porcelain tube. A power cable junction box characterized in that a pre-mold insulator compression device is provided with a guide stopper so that the degree of tightening of the pre-mold insulator can be easily seen.