JP3352566B2 - Bushings for power distribution equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bushing used for power distribution equipment such as a switch, a transformer, a circuit breaker and the like.

[0002]

2. Description of the Related Art Conventionally, in this type of bushing, a conductive rod is inserted and fixed in a bore provided in the axial direction. A fixed electrode is provided on the inner end side of the conductive rod, and an external lead wire is connected to the outer end side. Further, the bushing is provided with a flange, and the flange is fastened and fixed to a bushing support member such as a case of the power distribution equipment by a mounting bracket.

[0003]

When the power distribution equipment with the bushing is mounted outdoors, the external lead wire connected to the bushing may swing due to, for example, wind. When the external lead wire swings in this way, an external force acts on the bushing to which the lead wire is connected in accordance with the magnitude of the swing to deform the bushing. As a result, an internal stress mainly including bending stress is generated inside the bushing, and when the internal stress becomes excessive, the bushing may be damaged. In particular,
There is a risk of such damage at a portion such as a flange fixed to the case of the power distribution equipment.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a bushing for power distribution equipment capable of suppressing breakage due to swing of an external lead wire. It is in.

[0005]

According to one aspect of the present invention, there is provided an insulator fixed to a bushing support member of a power distribution device, and an inside of the insulator being axially fixed. A conductive rod fixed to the bushing support member, wherein the insulator is fixed to the bushing support member. The member is divided into a movable member disposed on the outer end side with respect to the fixed member, and the two members are connected to each other by a flexible insulating member. A first conductor inserted into the movable member; and a second conductor inserted into the movable member. The two conductors can be relatively rotated between the two conductors inside the insulating member. The gist of the present invention is to form a connecting portion for connecting to.

According to a second aspect of the present invention, in the bushing for a power distribution device according to the first aspect, at least one of the fixed member and the movable member is formed of a polymer material.

[0007]

According to the first aspect of the present invention, the insulator is divided into a fixed member and a movable member, and both members are connected by a flexible insulating member. Further, the conductive rod includes a first conductor and a second conductor, and both conductors are connected by a connecting portion inside the insulating member. In this connection part, relative rotation of both conductors is allowed. Therefore, in the bushing for power distribution equipment according to the present invention, while the insulating member is deformed by its flexibility, the movable member and the second conductor are connected to the fixed member and the first conductor at the connecting portion. By rotating, it is possible to deform the entire shape into a bent state. Therefore, even when the external lead wire swings, the bushing for power distribution equipment is deformed as described above according to the swing, and the internal stress generated in the bushing is reduced.

According to the second aspect of the present invention, in addition to the function of the first aspect of the present invention, since the external lead wire is swung by the bushing support member of the power distribution device, the internal portion is not fixed. Since the fixing member in which the stress is apt to be excessively large is formed of a polymer material, breakage in the member is suppressed.

[0009]

【Example】

(First Embodiment) A first embodiment in which the present invention is embodied in a bushing attached to a switch as a power distribution device will be described below with reference to FIGS. In the direction from the inside of the switch case to the outside, the front end side (FIG. 1)
The bushing configuration will be described with the upper part, the right side in FIG. 3 as the outer end side of the bushing, and the base side (lower side in FIG. 1, left side in FIG. 3) as the inner end side.

The bushings are fixed on each side of the switch case, which constitutes the bushing support member, as a power-side bushing and a load-side bushing in three phases. FIGS. 1 and 3 show only one phase of the power supply side bushing fixed to the side of the switch case 2. The other two-phase bushings are fixed to the case 2 at predetermined intervals in the left-right direction in FIG. 1 and in the direction perpendicular to the paper of FIG. 3 (hereinafter, referred to as the inter-phase direction). Alternatively, the description is omitted because it is the same as the bushing shown in FIG.

As shown in FIG. 1, the bushing 1 includes a fixed portion 3, a first cap portion 4 fixed to the fixed portion 3,
A cap portion 5 and a deformation portion 6 for connecting the first cap portion 4 and the second cap portion 5 are provided. These components 3, 4, 5, and 6 are arranged in the axial direction of the bushing 1 (the vertical direction in FIG. 1, hereinafter simply referred to as the axial direction). The fixing portion 3 is made of an epoxy resin as a polymer material, and the first cap portion 4, the second cap portion 5, and the deforming portion 6 are all molded using silicone rubber as a polymer material as a molding material. still,
The fixing part 3 and the first cap part 4 constitute a fixing member of the present invention,
The second cap 5 constitutes a movable member. In addition, the deformation part 6
Constitutes an insulating member connecting the fixed member and the movable member.

A flange 7 is formed so as to protrude substantially at the center of the outer periphery of the fixed portion 3 in the axial direction. Further, a rod-shaped conductive portion 9 covered with a conductive rubber 8 for preventing corona is inserted and fixed in the fixed portion 3 in the axial direction. The conductive portion 9 has a mounting hole 9a formed at an outer end thereof, and a fixed electrode (not shown) attached to an inner end thereof.

In the fixing portion 3, a portion on the outer end side from the position where the flange 7 is formed is reduced in diameter toward the outer end side, and is a mounting portion 10 having an outer peripheral surface formed into a tapered surface 10a. The fixing part 3 is inserted into a mounting hole 11 provided in the switch case 2, and is connected to the switch case 2 by a flange 7.
It is locked to the outer surface of. The mounting portion 10 of the fixing portion 3 is inserted into a through hole 12 formed in a low-cylindrical mounting bracket 13 with a lid. Further, the flange 7 of the fixing portion 3 is covered by the mounting bracket 13. A plurality of insertion holes 14 are formed in the mounting bracket 13 at regular intervals in the circumferential direction of the mounting bracket 13, and mounting bolts 15 implanted in the switch case 2 are provided in the insertion holes 14. It has been inserted. A tightening nut 16 is screwed on the upper portion of the mounting bolt 15, and the fixing portion 3 is fixed to the switch case 2 by tightening the tightening nut 16.

Two insulating folds 18 extending radially of the bushing 1 are formed on the outer peripheral surface of the first cap portion 4 at predetermined intervals along the axial direction. The number of the insulating folds 18 is appropriately selected from no folds to a plurality of folds depending on the condition of the place where the device is used. First cap part 4
Is formed with a fitting hole 17 from the inner end side, and the inner peripheral surface of the fitting hole 17 is a tapered surface 17a. Fitting hole 1
7 is fitted in the mounting portion 10 of the fixing portion 3 and has a fitting hole 17.
And the tapered surface 10a of the mounting portion 10
It is tightly fixed by tightening a nut 40 described later. Also, the outer end surfaces 9b, 10 of the conductive portion 9 and the mounting portion 10
b and the bottom surface 17b of the fitting hole 17 are similarly tightly fixed.

An insertion hole 22 extending in the axial direction is formed inside the first cap portion 4, and a first conductive rod 20 is inserted into the insertion hole 22 from the outer end side of the first cap portion 4. I have. A tubular conductive rubber 21 is arranged on the inner peripheral surface of the insertion hole 22. A screw portion 23 is formed at the inner end of the first conductive rod 20, and the screw portion 23 is screwed into the mounting hole 9 a of the conductive portion 9.

As shown in FIG. 2, a low columnar step 19 is formed on the outer end surface of the first cap portion 4, and a circumferential groove 27 extending in the circumferential direction is formed on the outer peripheral portion of the step 19. 19 are formed over the entire circumference. A screw portion (not shown) is formed on a portion of the first conductive rod 20 protruding from the outer end surface of the step portion 19, and a nut 40 is provided on the screw portion via a washer 39.
Is screwed. The nut 40 is fastened so that the first cap portion 4 is fixed to the mounting portion 10. Further, the outer end of the first conductive rod 20 is notched and the through-hole 2 is formed.
A flat portion 24 through which 4a is provided is provided.

As shown in FIG. 1, the second cap portion has a substantially cylindrical shape as a whole, and has an insulating fold 18 of the first cap portion 4 on the outer peripheral surface.
Similarly, the number of insulating folds 29 is formed in accordance with the condition of the place where the equipment is used. An insertion hole 30 extending in the axial direction is formed inside the second cap portion 5, and a second conductive rod 31 is inserted and fixed from the outer end side of the second cap portion 5 in the insertion hole 30. A tubular conductive rubber 32 is adhered to the inner peripheral surface of the insertion hole 30, and the outer peripheral surface of the second conductive rod 31 is adhered to the inner peripheral surface of the conductive rubber 32 in close contact therewith. A screw portion 33 is formed at the outer end of the second conductive rod 31. When the bushing 1 is in use, the screw portion 33 has a connection terminal (shown in FIG. 3) for an external lead wire 34 (shown in FIG. 3). No) is screwed and connected. Further, as shown in FIG.
The inner end of 1 is notched and has a flat portion 35 through which a through hole 35a is provided. The first conductor of the present invention is constituted by the conductive portion 9 and the first conductive rod 20.
The second conductive rod 31 forms a second conductor.

A stepped portion 36 having the same diameter as the stepped portion 19 and having a low columnar shape is formed on the inner end surface of the second cap portion 5. Step 3
A circumferential groove 37 extending in the circumferential direction is formed on the outer circumference of the step 6 over the entire circumference of the stepped portion 36. First cap part 4 and second cap part 5
And are connected by a substantially cylindrical deformation portion 6. In addition, on the outer peripheral surface of the deformed portion 6, an insulating fold 25 whose number is selected according to the use place of the device is formed. FIG.
As shown in FIG. 5, a sealing ridge 26 extending in the circumferential direction is formed on the inner peripheral surface on the inner end side of the deformed portion 6 over the entire circumference. Similarly, a sealing ridge 28 is formed on the inner peripheral surface on the outer end side of the deformed portion 6.

The sealing ridge 26 is fitted into the peripheral groove 27 of the step 19, and the deformed part 6 has an inner peripheral surface on the inner end side thereof on the outer peripheral surface of the step 19 provided on the first cap 4. Adhesively fixed. On the other hand, the sealing ridges 28 are
6, the deformed portion 6 has its inner peripheral surface on the outer end side bonded and fixed to the outer peripheral surface of the step portion 36 provided on the second cap portion 5. In the space formed by the outer end surface of the first cap portion 4, the inner end surface of the second cap portion 5, and the inner peripheral surface of the deformed portion 6, the first conductive rod 20 and the second conductive rod 35
1 and the flat surface 2 of each flat portion 24, 35 by the nut 42
4b and 35b are connected in an overlapping state. More specifically, the connection bolt 41 is inserted into the through hole 24a of the flat portion 24 via the washer 43,
The flat portion 35 is inserted through the through hole 35a. And
A nut 42 is screwed to the connection bolt 41 protruding from the flat portion 35 via a spring washer 44 for preventing loosening. Flat surface 24b, 35 of each flat portion 24, 35
b comes into contact in a pressed state by tightening the nut 42, whereby the first conductive rod 20 and the second conductive rod 35
Electrical continuity is ensured. Further, the tightening force of the nut 42 is appropriately adjusted, and the second conductive rod 31 is rotatable relative to the first conductive rod 20 about the connection bolt 41 as an axis. The flat portions 24 and 35, the through-hole 2
The connecting portion 60 is constituted by 4a, 35a, the connecting bolt 41, the nut 42, the washer 43, and the spring washer 44.

With the configuration described above, in this embodiment,
The second cap portion 5 and the second conductive rod 31 are connected to the first cap portion 4 and the first
The conductive rod 20 can be rotated by a predetermined angle relative to the connecting bolt 41 as an axis. At this time, the deformation part 6
In the above, due to the flexibility of the silicone rubber, a deformation occurs that allows the relative rotation of the second cap portion 5 and the second conductive rod 31. Further, the relative rotation of the second cap portion 5 and the second conductive rod 31 can be made in a plane including a vertical direction (a vertical direction in FIG. 1 and a vertical direction in FIG. 3), and is fixed to the switch case 2. The power-supply-side bushing and the load-side bushing are all rotatable in the same direction.

Next, the operation of the bushing 1 in this embodiment will be described. FIG. 3 shows a use state of the bushing 1 fixed to the side of the switch case 2. A terminal cover 45 is attached to the outer end of the second cap portion 5, and a connection terminal (not shown) for the external lead wire 34 is
The conductive rod 31 is screwed and connected to the screw portion 33 of the conductive rod 31.

When the external lead wire 34 swings due to wind or the like, the swinging causes the bushing 1 to move.
, An external force having a force component in a direction for deforming the bushing 1 in the vertical direction (the vertical direction in FIG. 3) acts.
Then, according to the magnitude of the external force, the second cap portion 5 and the second
The conductive rod 31 relatively rotates about the connecting bolt 41 of the connecting portion 60 as an axis, and the bushing 1 is deformed as shown in FIG. Owing to such deformation, the swing of the external lead wire 34 is absorbed, and internal stress, particularly bending stress, generated inside the bushing 1 is reduced. Therefore, according to the present embodiment, breakage of the bushing 1 due to the swing of the external lead wire 34 can be suppressed.
In addition, since the bending stress in the bushing 1 is reduced, the bending moment acting on the switch case 2 can be reduced.

Further, in the present embodiment, since the fixing portion 3 is formed by using an epoxy resin as a molding material, the fixing portion 3 is less likely to be damaged as compared with a case where porcelain is used as the material. . Therefore, when the external lead wire 34 swings, it is possible to suppress the damage caused by the stress in the flange 7 where the internal stress is particularly likely to increase.

In addition, the silicone rubber forming the first cap portion 4, the second cap portion 5, and the deformed portion 6 has excellent weather resistance and water repellency. 4, insulating folds 1 provided on the second cap portion 5 and the deformed portion 6
8, 29 and 25 are provided with antifouling property, and the bushing 1
Have improved electrical characteristics.

(Second Embodiment) Next, a second embodiment will be described focusing on differences from the first embodiment. The first
The same components as those in the embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In this embodiment, as shown in FIGS. 4 and 5, the flat portion 24 of the first conductive bar 20 and the flat portion 35 of the second conductive bar 31 are connected via a connecting member 46. I have. The connecting member 46 has two flat portions 47 and 48, and through holes 47a and 48a are formed in both flat portions 47 and 48. 4 and 5, the flat surfaces 48b and 48c of the flat portion 48 are perpendicular to the flat surfaces 47b and 47c of the flat portion 47.

The first conductive rod 20 and the connecting member 46 are connected by connecting bolts 49 and nuts 50 in a state where the flat surfaces 24b and 47b of the flat portions 24 and 47 are overlapped. That is, as shown in FIG.
9 is inserted through the through hole 47a of the flat portion 47 and the through hole 24a of the flat portion 24 via the washer 51. Further, a nut 50 is screwed to the connection bolt 49 protruding from the flat portion 24 via a spring washer 52 for preventing loosening. The flat surface 24b of each flat portion 24, 47,
47b is brought into contact in a pressed state when the nut 50 is tightened, so that electrical continuity between the first conductive rod 20 and the connecting member 46 is ensured. Further, by appropriately adjusting the tightening force of the nut 50, the connecting member 46 can be relatively rotated with respect to the first conductive rod 20 in the direction perpendicular to the paper of FIG. .

On the other hand, the connecting member 46 and the second conductive rod 3
1 is a flat surface 4 of both flat portions 48 and 35 as shown in FIG.
8b and 35b are overlapped with each other,
Similar to the connection in 7 and 24, they are connected by a connection bolt 53, a nut 54, a washer 55 and a spring washer 56. The second conductive rod 31 is rotatable with respect to the connecting member 46 in the direction perpendicular to the plane of FIG. 5 (the direction along the plane of FIG. 4) about the connection bolt 53 as an axis. The flat portions 24, 35, 47, 48, through holes 24a, 35a, 47a, 48a, connecting bolts 49,
A connecting portion 61 is constituted by 53, nuts 50 and 54, washers 51 and 55, and spring washers 52 and 56.

In this embodiment, a deformed portion 57 made of silicon rubber is provided as a member corresponding to the deformed portion 6 as an insulating member in the first embodiment. Same deformation part 5
7 has a substantially cylindrical shape, and its outer peripheral portion has a bellows structure. As in the first embodiment, the deforming portion 57 has a sealing ridge 58 formed on the inner peripheral surface on the inner end side fitted into the peripheral groove 27 of the step portion 19 and the inner peripheral surface. Are adhered and fixed to the outer peripheral surface of the step portion 19. Further, the deformed part 5
7 is a sealing ridge 5 formed on the inner peripheral surface on the outer end side.
9 is fitted into the peripheral groove 37 of the step portion 36, and the inner peripheral surface is adhesively fixed to the outer peripheral surface of the step portion 36.

The operation of the second embodiment having the above configuration will be described. In the present embodiment, the first
The conductive bar 20 and the second conductive bar 31 are connected. The connecting member 46 is rotatable relative to the first conductive rod 20, and the second conductive rod 31 is rotatable relative to the joining member 46 in a direction perpendicular to the rotation direction.
That is, the second conductive rod 31 is different from the first conductive rod 20
It is relatively rotatable in two directions. as a result,
The second conductive rod 31 and the second cap portion 5 in this embodiment can be relatively rotated in two directions around the bolts 49 and 53 while deforming the deformed portion 57 having the bellows structure. In the first embodiment, as shown in FIG. 3, the bushing 1 can be deformed only in the vertical direction. However, in the present embodiment, the degree of freedom of deformation of the bushing 1 is increased. The deformation of the bushing in the inter-phase direction (the direction perpendicular to the paper surface in FIG. 3) is also allowed. Therefore, in the present embodiment, the swing of the external lead wire 34 can be more effectively absorbed, and the occurrence of excessive internal stress inside the bushing 1 can be further suppressed. Further, since the deformed portion 57 of this embodiment has a bellows structure, the deformed portion 57 can be easily deformed. Furthermore, by forming the deformed portion 57 in a bellows structure, the creeping distance of the outer peripheral portion of the deformed portion 57 can be increased, and the electrical characteristics of the deformed portion 57 can be improved. In the present embodiment, even if the bushing is deformed in the interphase direction as described above,
A sufficient inter-phase distance is ensured so that bushings fixed adjacent to the switch cover 2 do not interfere with each other.

The above first and second embodiments can be implemented by changing the configuration as follows. (1) The first cap portion 4 and the second cap portion 5 are molded with silicone rubber. As a molding material, ethylene propylene rubber, butyl rubber, chloroprene rubber, or the like can be used in addition to the silicone rubber. Further, for the fixing portion 3, other than the epoxy resin, for example, the above-mentioned various rubbers, porcelain, polyester resin, fluorine resin and the like can be used.

(2) The deformed portion 6 and the deformed portion 57 are formed of silicon rubber, but other than this silicon rubber, ethylene propylene rubber, butyl rubber, chloroprene rubber or the like can be used.

(3) In the above embodiment, the case where the bushing 1 is attached to the cased switch is shown. However, the case where the bushing 1 is attached to another power distribution device such as an exposed switch, a transformer, a circuit breaker or the like. However, the same effect can be obtained.

(4) In the above embodiment, the deformed portions 6 and 57 constituting the insulating member are formed by members different from the first cap portion 4 and the second cap portion 5. The first shade 4
Alternatively, it can be configured integrally with the second cap portion 5.

(5) The direction in which deformation is allowed in the bushing 1 is not limited to the vertical direction or the interphase direction shown in the above embodiment, but may be changed as appropriate according to the mounting state of the switch.

(6) In the above embodiment, the fixing portion 3 and the first cap portion 4 are separate members, but both portions may be formed integrally. Hereinafter, technical ideas that can be grasped from the above embodiments will be described together with their effects.

(A) The bushing for power distribution equipment according to claim 1 or 2, wherein the insulating member having flexibility has a bellows structure. With such a configuration, the insulating member can be easily deformed.

[0038]

According to the bushing for power distribution equipment according to the first aspect, when the external lead wire swings, the bushing for power distribution equipment is deformed in accordance with the swing, and the internal stress of the bushing is deformed by the deformation. Can be eased. As a result, breakage of the bushing due to the swing of the external lead wire can be suppressed.

According to the second aspect of the present invention, in addition to the effects of the first aspect of the present invention, damage to the fixing member can be further suppressed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a state in which a bushing according to a first embodiment is fixed to a switch case.

FIG. 2 is an enlarged partial cross-sectional view showing a connecting portion.

FIG. 3 is an explanatory diagram showing a state in which a bushing fixed to the switch is deformed by swinging of an external lead wire.

FIG. 4 is an enlarged front sectional view showing a connecting portion in a second embodiment.

FIG. 5 is an enlarged left side sectional view showing a connecting portion.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... bushing (distribution equipment bushing), 2 ... switch case (distribution equipment, bushing support member), 3 ... fixed part (insulator, fixing member), 4 ... 1st cap part (insulator, fixing member), 5 ... second cap (insulator, movable member), 6,57 ...
Deformed part (insulating member), 9: conductive part (conductive rod, first conductor), 20: first conductive rod (conductive rod, first conductor),
31: second conductive rod (conductive rod, second conductor), 34: external lead wire, 60, 61: connecting portion.

Continuing from the front page (72) Inventor Kozo Kishimoto 1st character small needle in Inuyama City, Aichi Prefecture Energy Support Co., Ltd. (72) Inventor Yoshitomo Iwamoto 1st character small needle in Inuyama City, Aichi Prefecture Energy Support Co., Ltd. (72 ) Inventor Yoshitaka Hirate Inouyama-shi, Aichi Prefecture, 1 Kamikobari Energy Support Co., Ltd. (56) References JP-A-60-89008 (JP, A) JP-A 52-33099 (JP, U) JP-A 61-89 −85029 (JP, U) Actually open 1987-120235 (JP, U) Actually open 47-24599 (JP, U) Actually open 555-151087 (JP, U) (58) Fields investigated (Int. . ^7, DB name) H01B 17/26

Claims (2)

(57) [Claims] An insulator fixed to a bushing support member of a power distribution device, and a conductive rod fixedly inserted through the insulator in an axial direction, wherein an outer end of the conductive rod is provided. A bushing for power distribution equipment to which an external lead wire is connected on the side, wherein the insulator is divided into a fixed member fixed to the bushing support member and a movable member arranged on the outer end side of the fixed member. And the two members are connected by a flexible insulating member. The conductive rod includes a first conductor inserted through the fixed member, and a second conductor inserted through the movable member. And a conductor,
A bushing for power distribution equipment, wherein a connecting portion for connecting the two conductors to each other so as to be relatively rotatable is formed between the two conductors inside the insulating member. 2. The bushing for power distribution equipment according to claim 1, wherein at least one of the fixed member and the movable member is formed of a polymer material.