JP2549826Y2 - Bushing shrink tube mounting structure - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shrink tube mounting structure for a bushing.

[0002]

2. Description of the Related Art Conventionally, a bushing cover is attached by first caulking a lead wire and a metal fitting at the outer end of the bushing, and then molding a stress cone as a cover including the caulked portion. In some cases, the work of vulcanizing the cover after connecting the lead wire and the metal fitting at the outer end of the bushing is required, resulting in a very troublesome and high cost.

Therefore, a mounting structure has been devised which can easily connect the cover of the bushing and the lead wire as disclosed in Japanese Utility Model Application No. 2-112051 of the inventor's earlier application.

In the invention disclosed in the invention of Japanese Utility Model Application No. 2-112051, the outer end of the bushing is hermetically sealed in order to maintain watertightness instead of forming the stress cone integrally with the lead wire and the metal fitting at the outer end of the bushing. A member is arranged, an O-ring is interposed between the bushing and the sealing member, and an adhesive is applied to the inner surface of the stress cone covering the bushing to improve the sealing property. A heat-shrinkable shrink tube is covered at the joint with the wire, and the communication passage is securely closed to maintain watertightness in the bushing.

[0005]

[0007] Of course, even with such a bushing cover mounting structure, watertightness is sufficient, but the load stress of the lead wire is particularly applied to the vicinity of the stress cone and the shrink tube. There is no possibility that the shrink tube is slightly turned up by use, and there is a problem to be solved in that perfect watertightness is maintained.

The present invention has been made in view of such circumstances, and an object thereof is to provide a mounting structure having higher watertightness and capable of easily connecting a bushing cover and a lead wire. It is in.

[0007]

According to the present invention , a lead wire is crimped to an outer end of a bushing.
Attach the closed sealing member and seal the outer end face of the bushing.
The member and the extension of the lead wire from the sealing member
In a bushing structure in which a shrink tube that covers the joint between the cover and the lead wire is attached to the outer surface of the cover and the lead wire while covering with a cover having a separate structure, the shrink tube of the cover and the lead wire is At least one annular projection is formed at each of the mounting positions , and the annular projection formed on the lead wire is
In the state where the shrink tube is attached,
It includes an annular projection that abuts and engages the front end surface of the cover.
That it has to so that has as its gist.

[0008]

According to the above construction, the portions of the shrink tube abutting on the respective annular projections are pushed out in a state where the shrink tube is attached to the cover and the lead wire. Crimp the wire tighter. Then, the possibility of water entering from the seam between the cover and the lead wire is further reduced. In particular, there is no partial gap due to the annular projection. Only
Also, the annular protrusion of the lead wire is fitted with a shrink tube.
Annular projection that abuts and engages the front end surface of the cover
Part, so that the shrink tube
During thermal contraction, the annular projection acts as a stopper.
This prevents the seam from being displaced.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of a shrink tube mounting structure for a bushing according to the present invention;

The bushing 2 is a substantially cylindrical porcelain body having an annular cross section, and is formed on the outer peripheral surface of a known insulating fold. A large-diameter mounting flange portion 4 is formed on the outer periphery near the base end.

The bushing 2 is fixed to the large-diameter flange portion 4 with a fixing bracket 25 via an O-ring 3a, a regulating ring 3b surrounding the O-ring 3a, and a packing 3c. The gas-filled switchgear in which the arc gas is sealed is disposed in a state in which its base end portion enters the case 1.

A bore 5 extending in the axial direction of the bushing 2 is formed in the bushing 2, and a conductive rod 6 made of an alloy having a circular cross section in a diametrical direction is inserted through the bushing 2 in a non-contact state. The base end of the bushing 2 protrudes out of the bushing 2 from the base end thereof, and the tip end is disposed so as not to protrude beyond the outer end of the bushing 2 and near the outer end of the bushing 2. The conductive rod 6 has a nut 10 screwed to the base end thereof, and is fixed to the bushing 2 with the nut 10 and the sealing member 7. A male screw portion 6a is formed on the outer periphery of the conductive rod 6 on the distal end side.

A sealing member 7 made of an alloy for fixing the conductive rod 6 at the distal end thereof toward the distal end of the conductive rod 6 and closing the inner cavity 5 of the bushing 2 is mounted. The sealing member 7 includes a cylindrical portion 8 having an internal thread 8a which is screwed with the external thread 6a at the tip of the conductive rod 6 described above, and a bushing 2
A substantially conical body 9 having a flange 9a that closes the lumen 5 of the bushing and abuts against the front end surface of the bushing 2;
And a protruding portion 7a protruding on the opposite side to the cylindrical portion 8 with respect to. The sealing member 7 is always urged to the right in FIG. 1 by the nut 15 screwed to the male screw portion 6a of the conductive rod 6, and as a result, the conductive rod 6 is securely fixed in the bushing 2. I have.

An O-ring 11 is arranged between the main body 9 of the sealing member 7 and the front end face of the bushing 2. An annular groove 12 into which the O-ring 11 is inserted is formed by the main body 9 of the sealing member 7. 9 is formed.

At the protruding portion 7a of the sealing member 7, the leading end of the lead wire 14 is caulked, and the lead wire 1
4 extends forward from this part. On the outer periphery of the lead wire 14 near the sealing member 7, annular projecting portions 17, 18 made of a double butyl rubber material having self-fusing property are formed. In addition, one of the two annular projections 17 and 18 has one ring.
As shown in FIG. 1, the projection 17 is provided with a shrink
When the tube 16 is attached,
Formed at a position where the tip end surface of the rescone 13 abuts and engages.
ing.

A stress cone 13 as a cover is mounted so as to cover the outer end of the bushing 2 and the sealing member 7. The stress cone 13 is a cone-shaped cylindrical body made of ethylene-propylene rubber, and connects a large-diameter portion 13a that covers the outer end of the bushing 2 and a small-diameter portion 13b that covers the base end of the lead wire 14, and connects them. Appearance conical thick part 13c
It consists of An annular projection 19 similar to the above is formed on the outer periphery of the small diameter portion 13b.

A shrink tube 16 is mounted so as to cover the small diameter portion 13b and the lead wire 14 with the stress cone 13 mounted. Shrink tube 1
Reference numeral 6 denotes a cylindrical flexible member made of ethylene-propylene rubber.
18 and the annular projection 19 of the small diameter portion 13b push the shrink tube 16 from the inner surface, thereby deforming the shrink tube 16 into the shape of the projection.

An adhesive is filled between the inner surface of the stress cone 13 and the outer end of the bushing 2 and the sealing member 7 to form an adhesive layer 20. Next, a method of attaching the cover of the bushing will be described.

The lead wire 14 is passed through the stress cone 13 and the shrink tube 16 beforehand. In this state, the lead wire 14 is swaged to the outer end of the sealing member 7 and the conductive rod 6 is screwed to the inner end of the sealing member 7. Then, they are further tightened and integrated with a nut 15. Next, the integrated conductive rod 6 is inserted into the inner cavity 5 from the outer end side of the bushing 2,
The sealing member 7 is fixed to the outer end of the bushing 2 by tightening the nut 10 to the inner end of the conductive rod 6. (FIG. 2).

Next, an adhesive is applied to the entire inside of the stress cone 13 and the stress cone 13 is moved to the conductive rod 6 side.
The sealing member 7 is fixed so as to cover the caulked portion of the lead wire 14 and the outer end of the bushing 2. Thereafter, the annular projections 17 and 18 are provided on the outer periphery of the small diameter portion 13b of the stress cone 13 and the lead wire 14, and then the shrink tube 16 is slid along the lead wire 14 to thereby connect the small diameter portion 13b of the stress cone 13 and the lead. It is positioned so as to cover the line 14. Then, the shrink tube 16 also covers the annular protrusion 19 of the small diameter portion 13b and the annular protrusions 17 and 18 of the lead wire 14, and pushes the shrink tube 16 from the inner surface. Then, heat is applied to the shrink tube 16 to cause heat shrinkage, thereby further increasing the degree of adhesion.

With this configuration, the stress cone 13 can be formed separately from the lead wire 14 in advance, so that the stress cone 13 can be easily manufactured. Further, since the thick portion 13c is formed, even if the lead wire 14 moves and a stress is applied to the stress cone 13, there is no accident such as breakage.

The shrink tube 16 has a small diameter portion 1.
3b and the annular projection 17 of the lead wire 14,
18 to cover the three protrusions and to be very tightly adhered to the stress cone 13 and the lead wire 14 due to heat shrinkage.
Further, moisture and the like hardly enter.

In particular, the two annular projections 1 on the lead wire 14 side
There are 7 and 18 so that the water flowing along the lead wire 14 can be completely shut off. Further, water does not enter the gap between the bushing 2 and the stress cone 13 due to the adhesive layer 20. Moreover, the shrink tube 16 is thermally contracted.
When performing, the annular projection 17 formed on the lead wire 14,
One of the annular projections 17 of the
Abutting engagement with the tip surface as a stopper
To prevent the shrink tube 16 from sticking.
Can be ensured without gaps.

Although the embodiment of the present invention has been described in detail, the present invention can be implemented in other modes. For example,
In the above embodiment, the shrink tube 16 is made of ethylene-propylene rubber, but the material is not limited as long as it is flexible.

The number of annular projections is not necessarily limited, and a plurality of annular projections may be provided on the stress cone 13. Further, the method of forming the annular protrusion is not particularly limited. The present invention can be embodied with appropriate changes without departing from the spirit of the present invention, for example, the cover is not necessarily limited to the stress cone.

[0026]

[Effect of the Invention] As described in detail above , according to the present invention ,
An annular projection is formed at the joint of the cover and the lead wire at the position where the shrink tube is attached, so that not only can water leakage be maintained in consideration of aging and stress applied to the lead wire, but also leakage can occur. Creepage distance can be lengthened and further formed on the lead wire
The annular projection is a state where the shrink tube is attached
Includes an annular projection that abuts and engages the distal end surface of the cover at
When the shrink tube heat shrinks,
The protrusion acts as a stopper and the seam
To prevent tightness by the shrink tube.
This has the effect that it can be obtained without delay.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention.

FIG. 2 is a partially cutaway front view showing a state before assembling showing one embodiment of the present invention.

[Explanation of symbols]

2 bushing, 6 conductive bar, 7 sealing member, 10 nut, 11 O-ring, 13 stress cone as cover, 14 lead wire, 16 shrink tube, 20
... adhesive layer, 17, 18, 19 ... annular protrusion.

Claims (1)

(57) [Scope of request for utility model registration] 1. A lead wire (1) is connected to an outer end of a bushing (2).
4) Attach the sealing member (7) to which the crimped is attached, and
The outer end face of the washing (2), the sealing member (7) and the lead
The extension of the wire (14) from the sealing member (7) is
And a cover (13) that is separate from the cover (13), and the cover (1) is provided on the outer surfaces of the cover (13) and the lead wire (14).
3) In a bushing structure in which a shrink tube (16) covering a joint between the lead wire (14) is mounted, the cover (13) and the lead wire (14) are located at positions where the shrink tube (16) is mounted. At least one annular projection (17, 18, 19) is formed , and the annular projection (1) formed on the lead wire (14) is formed.
7, 18) are mounted with the shrink tube (16).
In contact with the front end surface of the cover (13)
A shrink tube mounting structure for a bushing, wherein the shrink tube mounting structure includes an annular projection (17) .