JP5601461B2 - Cable junction box sealed structure - Google Patents

Description

  The present invention relates to a sealed structure of a cable connection box.

Conventionally, in order to prevent leakage of insulating oil sealed in the inside of a cable connection box, a sealed structure in which several packings are mounted between a cable and a connection pipe covering the cable is known. (For example, refer to Patent Document 1 and Non-Patent Document 1).
The packing in the hermetic structure is pressed between the cable and the connecting pipe by the fastening fitting, and is crimped to the cable and the connecting pipe. In particular, since the fastening bracket presses the inclined surface toward the cable side against the packing, the gap between the cable and the connecting pipe is sealed in a state where the inner surface of the packing is strongly pressed against the surface of the cable.

JP-A-9-191551

1988 National Electrical Conference General Lecture Proceedings pp.1722-1723 Practical use of lead-free connection box for 275KV low-loss OF cable, Mitsuo Kanno, etc.

  However, in the case of the sealed structure described in the above document, if the elastic force of the packing decreases with long-term use, the surface pressure of the outer surface of the packing may not be applied to the connecting pipe side. In some cases, oil leakage is likely to occur between the packing and the connecting pipe.

  An object of the present invention is to improve the sealing performance of a sealed structure.

In order to solve the above problems, an aspect of the present invention provides:
In a cable connection box formed by covering a power cable with a connection pipe, a sealed structure for sealing between the power cable and the connection pipe,
A cable side packing closely contacting the outer peripheral surface of the power cable;
A trapezoidal packing that is interposed between the cable side packing and the connecting pipe, the inner surface being in close contact with the cable side packing is wider than the outer surface being in close contact with the connecting pipe;
A first tightening member having a first inclined surface facing the power cable side, and abutting the first inclined surface with one inclined surface of the trapezoidal packing;
A second tightening member having a second inclined surface facing the power cable side, and abutting the second inclined surface with the other inclined surface of the trapezoidal packing;
An urging member that elastically urges the first fastening member toward the trapezoidal packing so that one inclined surface of the trapezoidal packing and the first inclined surface are in close contact with each other;
A pressing member that presses the second tightening member toward the trapezoidal packing so that the other inclined surface of the trapezoidal packing and the second inclined surface are in close contact with each other;
An annular seal member that is sandwiched between the first tightening member or the second tightening member and the connection pipe and press-bonds to the first tightening member or the second tightening member and the connection pipe;
It is characterized by providing.

In the cable connection box formed by covering the power cable with the connection pipe, the sealed structure that seals the space between the power cable and the connection pipe includes the cable side packing that is in close contact with the outer peripheral surface of the power cable, the cable side packing, and the connection pipe. And a trapezoidal packing interposed between the two.
In this sealed structure of the cable connection box, the trapezoidal packing is fastened so as to be sandwiched between the first inclined surface of the first fastening member and the second inclined surface of the second fastening member, and the inner surface of the trapezoidal packing is the cable. Since the outer surface of the trapezoidal packing is in close contact with the connecting pipe, the power cable and the connecting pipe can be sealed with the cable side packing and the trapezoidal packing.
Further, since the sealed structure of the cable connection box includes the first tightening member or the second tightening member and the annular seal member that is crimped to the connection pipe, the cable side packing, the trapezoidal packing, and the seal member are provided. In cooperation, the sealing performance of the sealing structure can be improved.

In the sealed structure of the present invention, preferably, the seal member is provided on an outer peripheral surface side of the second fastening member,
Between the cable side packing and the connecting pipe, the first fastening member, the trapezoidal packing, and the second fastening member are pushed in order, and the trapezoidal packing is pushed into the first fastening member and the second fastening member. It is tightened with a member.

In this sealed structure of the cable connection box, each member is pushed in the order of the first fastening member, the trapezoidal packing, and the second fastening member between the cable side packing and the connection pipe, and between the cable side packing and the connection pipe. Each member is disposed in the box.
Then, instead of the first tightening member that is pushed deeper than the trapezoidal packing, an annular seal member is attached to the second tightening member that has a relatively short and shallow depth (depth) between the cable side packing and the connecting pipe. By attaching, the first tightening member, the trapezoidal packing, and the second tightening member can be easily assembled, and the assembly work of the sealed structure can be efficiently performed.

  According to the present invention, since the sealed structure of the cable connection box includes the trapezoidal packing and the annular sealing member that crimps the second fastening member and the connecting pipe, the oil seal of the trapezoidal packing and the sealing member is provided. It has both performance and can improve the sealing performance of the sealed structure.

It is sectional drawing which shows the sealing structure of a cable connection box. It is explanatory drawing which decomposed | disassembled and showed a part of sealing structure.

  Hereinafter, preferred embodiments for carrying out the present invention will be described with reference to the drawings. However, the embodiments described below are given various technically preferable limitations for carrying out the present invention, but the scope of the present invention is not limited to the following embodiments and illustrated examples.

  FIG. 1 is a cross-sectional view showing a sealed structure of a cable connection box. FIG. 2 is an explanatory view showing a part of the sealed structure in an exploded manner.

As shown in FIG. 1, the cable connection box 3 is formed by providing a sealed structure 100 on both ends of the connection pipe 2 that covers the power cable 1. In FIG. 1, a sealed structure 100 on one end side of the connection pipe 2 is illustrated.
Insulation oil is accommodated between the power cable 1 and the connection pipe 2 in the cable connection box 3, and the sealed structure 100 is connected to the connection pipe 2 so that the insulation oil does not leak from the cable connection box 3. At the end, the space between the power cable 1 and the connecting pipe 2 is sealed.

The power cable 1 is, for example, an OF cable (oil-immersed paper insulated cable), and includes a central conductor, an inner semiconductive layer, an insulating cigarette layer, an outer semiconductive layer, an aluminum coating layer, an anticorrosion sheath, and the like. In the power cable 1 of the cable connection box 3 portion, the aluminum coating layer is exposed on the outer peripheral surface of the cable.
The connecting pipe 2 includes, for example, a copper cylindrical pipe 2a and a sealing pipe portion 2b provided integrally with an end portion of the cylindrical pipe 2a. The sealing tube portion 2b has a screw hole 2d into which a guide portion 2c for supporting the spring unit 50 of the sealed structure 100 and a tightening bolt 62 for mounting the tightening unit 60 of the sealed structure 100 are screwed. doing.

  As shown in FIG. 1, the sealed structure 100 of the cable connection box includes a cable side packing 10 in close contact with the outer peripheral surface of the power cable 1, a cable side packing 10, a connection pipe 2 (sealing pipe portion 2 b), A trapezoidal packing 20 interposed therebetween, a first fastening member 30 having a first inclined surface 31 that contacts one inclined surface of the trapezoidal packing 20, and an other inclined surface of the trapezoidal packing 20 A second fastening member 40 having a second inclined surface 41, a spring unit 50 for biasing the first fastening member 30 toward the trapezoidal packing 20, and a second fastening member 40 pressed against the trapezoidal packing 20 The tightening unit 60 includes an O-ring 70 that is an annular seal member that is sandwiched between the second tightening member 40 and the connection tube 2 (sealing tube portion 2b).

The cable side packing 10 is an annular packing member that is in close contact with the outer peripheral surface of the power cable 1. The cable side packing 10 is sandwiched and held between the packing fixtures 11a and 11b, and the packing fixtures 11a and 11b are attached to the outer peripheral surface of the power cable 1 with an adhesive material 12 such as an epoxy putty, for example. Thus, the cable side packing 10 is fixed to the outer peripheral surface of the power cable 1. Note that the inner peripheral surface of the cable-side packing 10 has irregularities corresponding to the outer peripheral surface of the aluminum coating layer of the power cable 1, and the cable-side packing 10 is in a shape that can easily adhere to the aluminum coating layer.
Further, the packing fixture 11 a includes a fixing flange portion 13 extending in a direction intersecting with the cable, and a fixing bolt 14 screwed to the fixing flange portion 13. By fastening the fixing flange portion 13 and the sealing tube portion 2b with the fixing bolt 14, the connection tube 2 can be fixed to the power cable 1 via the packing fixture 11a.

The trapezoidal packing 20 is an annular packing member whose inner surface that is in close contact with the cable side packing 10 is wider than the outer surface that is in close contact with the connecting pipe 2 and whose cross section has a trapezoidal shape.
Further, the tapered surfaces extending from the inner surface edge to the outer surface edge of the trapezoidal packing 20 are inclined surfaces having the surfaces thereof facing away from the power cable 1.

The first tightening member 30 has a first inclined surface 31 directed toward the power cable 1 so as to face one inclined surface of the trapezoidal packing 20.
The first tightening member 30 is interposed between the cable side packing 10 and the connection pipe 2 (sealing pipe portion 2b).
The first tightening member 30 is biased toward the trapezoidal packing 20 by the spring unit 50 so that the first inclined surface 31 of the first tightening member 30 and one inclined surface of the trapezoidal packing 20 are in close contact with each other. The first tightening member 30 relatively presses the trapezoidal packing 20.

The second tightening member 40 has a second inclined surface 41 directed toward the power cable 1 so as to face the other inclined surface of the trapezoidal packing 20.
The second fastening member 40 is interposed between the cable side packing 10 and the connection pipe 2 (sealing pipe portion 2b).
The second fastening member 40 is pressed against the trapezoidal packing 20 by the fastening unit 60 so that the second inclined surface 41 of the second fastening member 40 and the other inclined surface of the trapezoidal packing 20 are in close contact with each other. Therefore, the second fastening member 40 relatively presses the trapezoidal packing 20.

The spring unit 50 includes a shaft member 51 that is pivotally supported by the guide portion 2c of the sealing tube portion 2b, and a plurality of disc springs 52 as urging members that are continuously provided with the shaft member 51 as an axis. Yes.
The shaft member 51 has one end of the shaft member 51 inserted through the guide portion 2 c so that the shaft member 51 can advance and retreat in the axial direction, and the other end is fitted in the hole 30 a on the base surface of the first fastening member 30. A plurality of disc springs 52 are elastic between the first tightening member 30 and the sealing tube portion 2b as the shaft member 51 advances and retreats at the guide portion 2c as the first tightening member 30 moves. It is designed to deform.
Then, the spring unit 50 elastically biases the first fastening member 30 toward the trapezoidal packing 20 by a repulsive force restored by the disc spring 52 that has been elastically deformed and contracted. The spring unit 50 elastically presses the first tightening member 30 toward the trapezoidal packing 20 so that the first inclined surface 31 is in close contact with one inclined surface of the trapezoidal packing 20.

The tightening unit 60 includes a tightening flange 61 having a bolt screw hole 61a and a screw screw hole 61b, a tightening bolt 62 screwed into the bolt screw hole 61a, and a screw screw hole 61b. And a fastening screw 63 which is a set screw type pressing member.
The tightening bolt 62 is screwed into the screw hole 2d of the sealing tube portion 2b through the bolt screw hole 61a, and the tightening bolt 62 fastens the tightening flange 61 to the connecting tube 2. The fastening flange 61 attached to the connecting pipe 2 (sealing pipe part 2b) is such that the second fastening member 40 interposed between the cable side packing 10 and the sealing pipe part 2b does not come out between them. In this manner, the second fastening member 40 is in contact with the base surface. The screw screw hole 61b in the tightening flange 61 is at a position corresponding to the second tightening member 40, and the tightening screw 63 screwed into the screw screw hole 61b is the second tightening member. 40 base surfaces can be contacted.
Then, the tightening screw 63 of the tightening unit 60 is screwed into the second tightening member 40 so that the tightening screw 63 presses the second tightening member 40 toward the trapezoidal packing 20. Then, the tightening unit 60 presses the second tightening member 40 toward the trapezoidal packing 20 so that the second inclined surface 41 is in close contact with the other inclined surface of the trapezoidal packing 20.

  The fixing bolt 14 and the fastening bolt 62 may be a common bolt, and the fixing flange portion 13 and the sealing tube portion 2b are fastened with the common bolt, and the fastening flange 61 is fastened to the sealing tube portion 2b. You may do it.

  The O-ring 70 is attached so as to be press-fitted into an annular groove provided on the outer peripheral surface of the second fastening member 40, and is crimped to the second fastening member 40 and the connection pipe 2 (sealing pipe part 2b). Yes.

  Next, the assembly process of the sealed structure 100 of the cable connection box and the sealing function (oil sealability) of the sealed structure 100 will be described.

  First, the power cables 1 are connected to each other in a predetermined procedure, and the packing fixtures 11 a and 11 b are attached to the aluminum coating layer of the power cable 1, and the cable side packing 10 is fixed to the outer peripheral surface of the power cable 1. Next, the connecting pipe 2 is set in an arrangement that covers the connecting portion of the cable.

  At this time, as shown in FIG. 2, the spring unit 50 is disposed in the guide portion 2 c in the sealing tube portion 2 b of the connection tube 2.

Thereafter, the respective members are pushed in the order of the first fastening member 30, the trapezoidal packing 20, and the second fastening member 40 between the cable side packing 10 and the connecting pipe 2 (sealing pipe portion 2b), and the cable side packing. Each member is disposed between 10 and the sealing tube portion 2b.
Since the O-ring 70 is attached to the outer peripheral surface of the second tightening member 40, the O-ring 70 is caused when the second tightening member 40 is pushed between the cable side packing 10 and the sealing tube portion 2b. Since the frictional resistance is applied, the second tightening member 40 may be difficult to push in as compared to the first tightening member 30.
However, if the O-ring 70 is attached to the first tightening member 30 to be inserted deeper than the trapezoidal packing 20, the first tightening member 30 is spring-loaded due to the frictional resistance caused by the O-ring 70. It takes time to insert the unit 50 until it abuts against the unit 50, and the assembly work efficiency may be deteriorated. Further, there is a concern in work management that the first tightening member 30 is pushed halfway.
Therefore, the degree of insertion (between the cable-side packing 10 and the sealing tube portion 2b) is relatively short and shallow, and the O-ring 70 attached to the second tightening member 40 is more suitable for the sealed structure 100. The O-ring 70 is attached to the second fastening member 40 because it is preferable from the viewpoint of the work efficiency of the assembly work.

Next, the fastening flange 61 in which the fastening screw 63 is attached to the screw screw hole 61 b is fastened to the sealing tube portion 2 b with the fastening bolt 62. In addition, after fastening the fastening flange 61 to the sealing tube portion 2b, the fastening screw 63 may be screwed into the screw screw hole 61b.
Furthermore, as shown in FIG. 1, the sealing structure 100 which seals between the power cable 1 and the connecting pipe 2 is assembled by fastening the fixing flange part 13 and the sealing pipe part 2b with the fixing bolt 14.

Then, the degree to which the tightening screw 63 in the tightening unit 60 of the sealed structure 100 is screwed into the second tightening member 40 is adjusted, and the second tightening member 40 is converted into the trapezoidal packing 20 by the tightening unit 60. When pressed, the spring unit 50 presses the first fastening member 30 toward the trapezoidal packing 20 by the repulsive force of the disc spring 52.
The inner surface of the trapezoidal packing 20 sandwiched between the first tightening member 30 and the second tightening member 40 is pressed against the cable side packing 10, and the outer surface of the trapezoidal packing 20 is the sealing tube portion 2b. The oil seal by the trapezoidal packing 20 is made by press-bonding to.
In particular, the trapezoidal packing 20 sandwiched and clamped between the first inclined surface 31 and the second inclined surface 41 facing the power cable 1 side follows the inclined surfaces 31 and 41, and the inner surface thereof is the cable-side packing 10. Therefore, the oil sealability on the inner surface side of the trapezoidal packing 20 is stable. Furthermore, since the width | variety of the inner surface of the trapezoid packing 20 is wide, there exists more favorable oil-seal performance.
On the other hand, since the O-ring 70 is attached to the outer peripheral surface of the second tightening member 40, the oil seal property on the outer surface side of the trapezoidal packing 20 can be compensated by the oil seal property by the O-ring 70. The outer surface of the trapezoidal packing 20 and the O-ring 70 cooperate to provide good oil seal performance.

As described above, the sealed structure 100 of the cable connection box includes the O-ring 70 attached to the outer peripheral surface of the second fastening member 40 in addition to the trapezoidal packing 20. It also has oil seal performance and improves the sealing performance of the sealed structure 100.
In particular, when the elastic force of the trapezoidal packing 20 decreases with long-term use, the surface pressure with which the trapezoidal packing 20 presses against the sealing tube portion 2b decreases, and the oil sealability on the outer surface side of the trapezoidal packing 20 deteriorates. Even if this occurs, the oil sealability by the O-ring 70 is added, so that the oil sealability as the sealed structure 100 can be maintained.
Note that the inner surface of the trapezoidal packing 20 is more strongly pressed against the cable-side packing 10, and the initial surface pressure is relatively high. Therefore, even if the elastic force of the trapezoidal packing 20 is reduced, the trapezoidal packing 20 There is almost no abnormality in the oil sealability on the inner surface side of the.

  Of the first tightening member 30 and the second tightening member 40 disposed so as to sandwich the trapezoidal packing 20, the trapezoidal packing 20 is not the first tightening member 30 disposed deeper than the trapezoidal packing 20. The O-ring 70 is attached to the second tightening member 40 which is on the near side and relatively short to be inserted between the cable side packing 10 and the sealing tube portion 2b. The trapezoidal packing 20 and the second fastening member 40 can be easily assembled, and the assembly work of the sealed structure 100 can be performed efficiently.

In the above embodiment, the O-ring 70 is provided on the outer peripheral surface of the second tightening member 40, but the present invention is not limited to this, and the outer surface of the first tightening member 30 is provided on the outer peripheral surface. An O-ring 70 may be provided.
Further, a concave groove is provided on the inner peripheral surface side of the sealing tube portion 2b, and an O-ring is inserted therein, and the O-ring is crimped to at least one of the second fastening member 40 and the first fastening member 30; You may make it closely_contact | adhere between the sealing pipe part 2b and the 2nd clamping member 40, or between the sealing pipe part 2b and the 1st clamping member 30. FIG.

  In addition, it is needless to say that other specific detailed structures can be appropriately changed.

DESCRIPTION OF SYMBOLS 1 Power cable 2 Connection pipe 2a Cylindrical pipe 2b Sealing pipe part 3 Cable connection box 10 Cable side packing 20 Trapezoid packing 30 1st clamping member 31 1st inclined surface 40 2nd clamping member 41 2nd inclined surface 50 Spring unit 51 Shaft member 52 Disc spring (biasing member)
60 Tightening unit 61 Tightening flange 62 Tightening bolt 63 Tightening screw (pressing member)
70 O-ring (seal member)
100 Sealed structure of cable connection box

Claims (2)

In a cable connection box formed by covering a power cable with a connection pipe, a sealed structure for sealing between the power cable and the connection pipe,
A cable side packing closely contacting the outer peripheral surface of the power cable;
A trapezoidal packing that is interposed between the cable side packing and the connecting pipe, the inner surface being in close contact with the cable side packing is wider than the outer surface being in close contact with the connecting pipe;
A first tightening member having a first inclined surface facing the power cable side, and abutting the first inclined surface with one inclined surface of the trapezoidal packing;
A second tightening member having a second inclined surface facing the power cable side, and abutting the second inclined surface with the other inclined surface of the trapezoidal packing;
An urging member that elastically urges the first fastening member toward the trapezoidal packing so that one inclined surface of the trapezoidal packing and the first inclined surface are in close contact with each other;
A pressing member that presses the second tightening member toward the trapezoidal packing so that the other inclined surface of the trapezoidal packing and the second inclined surface are in close contact with each other;
An annular seal member that is sandwiched between the first tightening member or the second tightening member and the connection pipe and press-bonds to the first tightening member or the second tightening member and the connection pipe;
A sealed structure of a cable connection box, comprising: The seal member is provided on the outer peripheral surface side of the second fastening member,
Between the cable side packing and the connecting pipe, the first fastening member, the trapezoidal packing, and the second fastening member are pushed in order, and the trapezoidal packing is pushed into the first fastening member and the second fastening member. 2. The sealed structure of a cable connection box according to claim 1, wherein the structure is tightened with a member.

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