JPH048596Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention sprays gas against the arc that occurs between the fixed electrode and the movable electrode when the switch is opened, and actively extends the arc. relates to a puffer-type arc extinguishing device for a switch configured to extinguish the arc by blowing it out.

Prior Art This type of conventional arc extinguishing device has a fixed cylinder arranged around the outer periphery of a fixed electrode, a piston fixed to the outer periphery of a movable electrode, and a pressure chamber formed in the cylinder to operate the switch. When the circuit opens, the internal pressure of the pressure chamber is increased as the piston moves, and the gas in the pressure chamber is blown against the arc generated between both electrodes, actively stretching the arc and extinguishing it. It was configured.

However, this type of puffer-type arc extinguishing device not only has a complicated structure because it has many parts such as cylinders, pistons, and shield rings, but also has fixed parts such as fixed electrodes and cylinders during assembly. It is very troublesome to center movable parts such as the movable electrode and the piston, and it takes a considerable amount of time to assemble, resulting in the above-mentioned problem of complicated structure and high production cost of the device.

In addition, in terms of reducing the weight of the switch and operating the switch, a puffer-type arc extinguisher using a conventional piston and cylinder would be heavier, and since the piston moves within the cylinder during the opening/closing operation, the frictional resistance between the two As a result, a large moving load is applied to the movable electrode, which not only makes the opening/closing operation difficult, but also causes the problem that the opening/closing operation of the movable electrode becomes unstable.

Therefore, in recent years, a puffer-type arc extinguishing device has been proposed in which a pressure chamber is formed by a bellows instead of the cylinder, piston, etc. to simplify the structure and facilitate manufacturing.

However, in a patchwork arc extinguishing device that uses such a bellows, the bellows is made of metal or resin, so it is difficult to use as a bellows that is arranged close to the arc generation point in the limited space inside the switch case. The following problems still remained.

In other words, in the case of metal bellows, although it has arc resistance, the manufacturing cost is high due to the high component cost, and since it is made of metal, it deteriorates over time and puts a load on the opening and closing movements of the movable electrode. There was a problem that the opening/closing operation of the switch became difficult.

On the other hand, in the case of resin bellows, there is a problem in terms of arc resistance, so the bellows must be placed away from the arc generation point, and therefore, there is a need to place the bellows and the movable electrode between the bellows and the movable electrode. It is necessary to install a transmission mechanism to transmit the opening/closing motion of the device, which complicates the structure of the entire device, resulting in an increase in manufacturing costs.

Purpose of the invention This invention was made to solve the above-mentioned problems, and its purpose was to construct a pressure chamber with bellows, unlike the conventional structure equipped with cylinders, pistons, etc. This not only simplifies the structure and facilitates manufacturing, but also reduces manufacturing costs, makes the opening/closing movement of the movable electrode lighter, and stabilizes the opening/closing movement of the movable electrode. An object of the present invention is to provide a puffer-type arc extinguishing device for a switch using a bellows that is strong against arc heat when generated.

Structure of the invention The puffer-type arc extinguishing device for a switch according to this invention consists of a bellows attached to the base of a movable electrode to form a pressure chamber, made of flame-retardant fiber, and the same fiber is impregnated with a sealant. The main point is that it is equipped with a coil spring.

Embodiment An embodiment embodying this invention will be described below with reference to FIGS. 1 to 3.

In the figure, 1 is a gas-filled switch case filled with an arc-extinguishing gas such as SF6, and 2 and 3 are bushings that are penetrated and fixed to the corresponding left and right side walls of the switch case 1 for each phase. A conductive rod 5 having one end to which a lead wire 4 is caulked is inserted and fixed into the bushings 2 and 3, and a connecting fitting 6 is fastened to the inner end of the conductive rod 5. Reference numeral 7 denotes a cylindrical locking flange formed on the outer periphery of the connecting fitting 6, and is fitted onto the inner end surfaces of the bushings 2 and 3 via a regulating ring 8 and an O-ring 9.

Reference numeral 10 denotes a fixed electrode that is screwed onto the inner end surface of the connection fitting 6 of the bushing 2, and
The nut 11 screwed onto the outer periphery of the base end is connected to the spring washer 11
It is firmly fixed by being tightened to the fixed electrode 10 via a. The fixed electrode 10 has a guide hole 10a which is opened at the tip thereof and is bored in the axial direction, and a through hole 10b that communicates with the outside is formed at the base end of the guide hole 10a, and is introduced into the guide hole 10a. The arc-extinguished gas is discharged to the outside of the fixed electrode 10.

Reference numeral 12 denotes a rod-shaped fixed electrode that is screwed onto the inner end surface of the connection fitting 6 of the bushing 3.
The fixed electrode 12 is formed to have the same outer diameter as the fixed electrode 10 and has a long length. Note that the nut 13 and spring washer 13a are screwed onto the base end of the fixed electrode 12 in the same manner as the nut 11 and spring washer 11a to firmly tighten the fixed electrode 12 to the connection fitting 6.

Reference numeral 14 denotes a movable electrode that is slidably provided on the outer periphery of the fixed electrode 12 along the axial direction.
The movable electrode 14 has a contact 15 formed by dividing a conductive cylindrical body into four in the longitudinal direction, and arranges it so as to cover the outer periphery of the fixed electrode 12. The outer periphery of both ends of the movable electrode 14 is secured by a pair of garter springs 16 and 17. It is constructed by bundling. The garter spring 16 on the tip side is covered with an arc-resistant tube 18 made of Teflon or the like.

Reference numerals 19 and 20 denote contact portions protruding from the inner peripheral surface of both ends of the contactor 15, which are capable of sliding contact with the outer periphery of the fixed electrode 12, and which are connected to the contact portion 19 on the tip side.
is also capable of sliding contact with the opposing fixed electrode 10. Reference numeral 21 denotes a regulating ring fitted to the inner circumferential surface of each contactor 15, and is adapted to regulate the inner diameter of the movable electrode 14.

Reference numeral 22 denotes a flange portion projecting outward from the outer periphery of the center portion of the contactor 15 . Reference numeral 23 denotes a mounting hole 23 formed at the center of the outer periphery of the flange 22 of the contactor 15.
The ring-shaped regulating member is loosely inserted at point a and is made of insulating synthetic resin, and the depth of its mounting hole 23a is equal to the length of the flange 22 in the left-right direction (in FIG. 1). The inner diameter of the movable electrode 14 is larger than the outer diameter of the flange 22 of the movable electrode 14 . Further, both outer circumferential surfaces of the regulating member 23 are cut off in the vertical direction to provide flat portions 23b. 24 is the same regulating member 23
As shown in FIG. 3, a bolt insertion hole 2 is provided around the mounting hole 23a at a position in the cross direction.
5 is a gas communication hole formed in an arc shape so as to be located between the bolt insertion holes 24.

Reference numerals 26 and 27 are support tubes disposed in a narrow manner at both ends of the regulating member 23, and are formed into a bottomed tube shape made of fiber-reinforced plastic made of vinylon, tetron, etc., which have excellent insulation and gas resistance. has been done. The support cylinders 26 and 27 are loosely inserted into the movable electrode 14 through insertion holes 26a and 27a formed at the center of the bottom thereof, and are formed at the bottom corresponding to the bolt insertion hole 24 of the regulation member 23. Bolt insertion holes 28, 29 and regulating member 23
A bolt 30 is inserted through the bolt insertion hole 24, and a nut 30a is tightened to the tip of the bolt 30 to connect them to each other.

That is, both support cylinders 26 and 27 are connected to the regulating member 23.
By interposing the movable electrode 14, a fitting groove 44 is formed in which the collar portion 22 of the movable electrode 14 is movably fitted, and the movable electrode 22 can be moved in the diametrical direction and the axial direction (horizontal direction in FIG. 1). I have to. Further, a groove formed between the flat portion 23b of the regulating member 23 and both support tubes 26 and 27 is defined as a vertical groove 31.

Reference numerals 32 and 33 designate gas communication holes formed in arcuate shapes at the bottoms of the support tubes 26 and 27, respectively, so as to correspond to the gas communication holes 25 of the regulating member 23. Reference numeral 34 denotes a mounting groove formed to rotate around the inner periphery of the support cylinder 27.

Reference numeral 35 denotes a bellows whose one end is airtightly attached to the attachment groove 6a provided on the outer periphery of the connecting fitting 6 by a tightening band 36, and the other end is attached to the attachment groove 34 of the support cylinder 27. Similarly, it is attached in an airtight manner by a tightening band 37. The bellows 35 is strong against decomposition gas of arc-extinguishing gas, and
Aromatic polyamide fiber (trade name "Konex" manufactured by Teijin Co., Ltd. in this example), which is a disaster prevention fiber with excellent disaster prevention properties, is impregnated with a sealant such as epoxy resin to prevent leakage of compressed gas from the folds. It is formed by arranging a coil spring 35a inside the aromatic polyamide fiber. Note that the disaster prevention fibers are arranged in a direction that intersects the folds of the disaster prevention fibers with respect to the coil spring 35a.

C is bellows 35, bushing 3 and support tube 2
This is a pressure chamber surrounded by 7. Reference numeral 38 is a truncated orifice cone screwed into the tip of the support tube 26, and is made of a synthetic resin having excellent arc resistance and insulation properties. Note that the orifice cone 38 is prevented from rotating by a set screw 39 screwed into the outer periphery of the support cylinder 26. Reference numeral 40 denotes a nozzle provided at the tip of the orifice cone 38, and is formed to be insertable into the fixed electrode 10.

Reference numeral 41 denotes a drive shaft which is rotatably supported in the switch case 1 below the fixed electrode 12 so as to be openable and closable, and can be externally operated by a manual operation mechanism (not shown). Reference numeral 42 denotes a pair of drive levers whose base ends are bolted to the drive shaft 41 for each phase, and the control member 23, the support tube 26, A vertical groove 31 surrounded by
It is attached to allow some movement.

The operation of the switch equipped with the puffer type arc extinguishing device configured as described above will now be described.

FIG. 1 shows the open state, and when the drive shaft 41 is rotated in the closing direction by external operation, the drive lever 4
2 is also rotated in the same direction, thereby supporting cylinder 2
The movable electrode 14, bellows 35, and orifice cone 3 are loosely fitted in the fitting groove 44 between 6 and 27.
8 are also moved integrally in the input direction. As a result, the movable electrode 14 is brought into sandwiched contact with the fixed electrode 10, and the bellows 35, which has been contracted as shown in FIG. 1, is expanded as it moves in the closing direction.
Then, the internal pressure in pressure chamber C decreases,
Gas in the switch case 1 is sucked into the bellows 35 through the nozzle 40 and the gas communication holes 25, 32, and 33.

When the drive lever 42 is rotated in the direction of opening the circuit via the drive shaft 41 by an external operation from the closed circuit state shown by the chain line in FIG. 14. The bellows 35 are moved together in the opening direction. Then, the movable electrode 14 is connected to the fixed electrode 10.
When the electrodes 10 and 14 are separated from each other, an arc is generated between the tips of the electrodes 10 and 14. At that time, the bellows 35 is the first
When the pressure chamber C is reduced in size and the internal pressure in the pressure chamber C increases as shown by the solid line in the figure, the gas in the bellows 35 is regulated by the support cylinders 26 and 27 without leaking to the outside due to the action of the sealant impregnated in the bellows 35. The gas is ejected to the outside through the gas communication holes 25, 32, 33 of the member 23 and the nozzle 40 of the orifice cone 38, and is vigorously blown against the arc occurring between the electrodes 10, 14.

Therefore, the arc that occurs when the circuit is opened is the bellows 3.
The arc is elongated by the gas ejected from inside 5, and is finally blown away to efficiently extinguish the arc.

SF6, which is the arc-extinguishing gas filled in the switch case 1, generates decomposable gas when the arc is extinguished, but in this embodiment, the bellows 35 is formed from aromatic polyamide fiber, so the same decomposition occurs. There is no risk that the bellows will deteriorate due to the gas.

Furthermore, since the aromatic polyamide fiber has disaster prevention properties with an LOI value (limiting oxygen index) of 28 to 32, there is no risk of bearing being affected by the arc heat generated between the electrodes.

The LOI value is a numerical value that indicates the flame retardancy of a substance; the higher the value, the more oxygen is required to burn, and generally speaking, if the LOI value is 26 or higher, it has disaster prevention properties.

This invention is not limited to the above-mentioned embodiment, and instead of aromatic polyamide fiber as a disaster prevention fiber, the bellows 35 is made by impregnating Proban-treated cotton (trade name "Proban" manufactured by Kurashiki Boseki Co., Ltd.) with Epoquin resin. may be formed.

The LOI value of this Proban processed cotton is also 28-32,
Has disaster prevention properties.

Further, by arranging the disaster prevention fibers in the direction in which the folds intersect with the coil spring 35a, not only the elasticity of the bellows is improved, but also the strength against the elastic movement is improved.

Effects of the invention As detailed above, this invention uses bellows to form the pressure chamber instead of conventional cylinders, pistons, etc., which not only simplifies the structure and facilitates manufacturing, but also is made of disaster-prevention fiber, which is impregnated with a sealant and equipped with a coil spring. This prevents gas leakage from the folds, and unlike the conventional structure that uses metal bellows, it is easy to manufacture. In addition to reducing costs and the weight of the device, the opening/closing movement is light, and the opening/closing movement of the movable electrode can be stabilized for many years. Also, unlike the conventional structure that uses resin bellows, It is said that it has excellent arc resistance, so it can be placed near the arc generation point in the switch case without causing any problems, contributing to the miniaturization and simplification of the entire device. It is an effective and excellent idea for industrial use.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the open state of a switch equipped with a Patshua type arc extinguishing device embodying this invention;
FIG. 2 is a sectional view showing the assembled state of the regulating member and the support tube, and FIG. 3 is a cross-sectional view of the regulating member. 1... Switch case, 2, 3... Bushing,
10, 12... fixed electrode, 14... movable electrode, 3
5...Bellows, 35a...Coil spring,
38... Orifice cone, 41... Drive shaft, 4
2... Drive lever.

Claims (1)

[Claims for Utility Model Registration] A movable electrode is connected to and separated from a fixed electrode, and is configured to be opened and closed as the movable electrode moves. A pressure chamber is formed by a bellows so that the internal pressure increases, and the pressure is applied to the outside of the tip of the movable electrode so that the gas in the pressure chamber is blown against the arc generated between both electrodes when the circuit is opened. A switch with an orifice cone communicating with a chamber, characterized in that the bellows 35 is made of flame-retardant fiber, the fiber is impregnated with a sealant, and a coil spring 35a is attached. Arc extinguishing device.