JPS6347217B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vacuum interrupter, and more particularly to a vacuum interrupter equipped with a coil electrode that applies a magnetic field parallel to an arc generated during a thermal break.

Conventionally, vacuum interrupters have been provided that apply a magnetic field parallel to the arc, a so-called axial magnetic field (longitudinal magnetic field), with the aim of improving shearing performance, and the coil for generating the magnetic field generates the arc. Generally, they are provided on the backs of a pair of contact electrodes that can be freely approached and separated.

An example of a conventional vacuum interrupter of this kind that applies an axial magnetic field is shown in FIGS. 1 and 2.
In the figure, reference numeral 1 denotes a vacuum container, which is composed of insulating tubes 11a and 11b made of glass or ceramics, and end plates 12 and 13 made of metal that seal both ends of the insulating tubes 11a and 11b in the axial direction. . A contact electrode 3a is provided at the inner end of the lead rod 2a which is hermetically fixed to the end plate 12 through a coil electrode 4a. Also, the other end plate 13
A lead rod 2b is movably provided through the bellows 14 in an airtight manner, and a contact electrode 3b is provided at the inner end of the lead rod 2b via a coil electrode 4b.

Each of the coil electrodes 4a and 4b is constructed as shown in FIG.
is composed of a plurality of arms 41 extending radially outward from the lead rod 2a, and a plurality of circular arc parts 42 with one end connected to the outer end of each arm 41, and the tip of each circular arc part 42 is connected. Contact electrode 3a via conductor 43
is connected to the back of the As a result, the coil electrode 4 is placed between the lead rod 2a and the contact electrode 3a.
a, the current is changed to a loop current surrounding the lead rod 2a, and a magnetic field is generated in the direction perpendicular to the contact electrodes 3a and 3b, that is, in the axial direction (magnetic field parallel to the arc).
It is designed to occur.

In FIG. 1, 15 is an intermediate shield, 16a
and 16b are auxiliary shields, and 17 is a bellows shield, each of which is a shield body made of non-magnetic stainless steel, which captures the metal vapor scattered from the pair of contact electrodes 3a and 3b and aims to relax the electric field. .

One contact electrode 3b is moved up and down via the lead rod 26 in the figure to contact and separate from the other contact electrode 3a, thereby making and breaking the electrical circuit.

By the way, in the vacuum interrupter having the above-mentioned configuration, the coil electrodes 4a and 4b for generating an axial magnetic field are provided at the backs of the contact electrodes 3a and 3b.
It is difficult to apply a parallel (linear) magnetic field to the arc by simply providing a and 4b on the back of one of the contact electrodes 3a and 3b. Part of the magnetic field becomes curved. As a result, an effective axial magnetic field is not applied to the arc, causing problems such as the arc dispersion effect weakening and the arc becoming more likely to concentrate.

Therefore, as described above, the coil electrodes 4a and 4b are respectively provided on the backs of the pair of contact electrodes 3a and 3b so as to be located on both sides of the arc column in the axial direction. 4b to form a composite magnetic field to effectively disperse the arc.

However, a pair of contact electrodes 3a that come into contact with and separate from each other,
Since the coil electrodes 4a and 4b are respectively provided on the back of the movable contact electrode 3b, the coil electrode 4b provided on the back of the movable contact electrode 3b is connected to the other coil electrode 4a in order to move when disconnected. The distance between them will widen. For this reason, the composite magnetic field gradually attenuates as the distance between the electrodes increases during the annealing process, and the dispersed arc becomes concentrated from the middle to the final stage of the annealing process due to the attenuation of the magnetic field. There was a problem that reached the point where it became impossible to disconnect.

For this purpose, a pair of contact electrodes 3 that move apart
There is a limit to the improvement in shearing performance (shrinking capacity) by a vacuum interrupter in which coil electrodes 4a and 4b are provided at electrodes a and 3b, respectively.

Further, providing the coil electrodes 4a and 4b on the backs of the pair of contact electrodes 3a and 3b, respectively, has the problem of increasing the number of parts and joining (brazing) points, resulting in poor durability. In particular, since the movable side is provided with the coil electrode 4b, the movable weight increases, the impact increases, and the durability decreases.

The present invention aims to provide a vacuum interrupter that improves shearing performance and is miniaturized by solving the problems described above in the vacuum interrupter of the type that applies an axial magnetic field. This is the purpose.

Next, an embodiment of the present invention will be explained based on FIGS. 3 to 5. In these figures, the same reference numerals as those in FIGS. 1 and 2 above indicate equivalent products. Therefore, a detailed explanation of these will be omitted.

That is, the vacuum container 1 includes a metal cylinder 10 made of non-magnetic stainless steel, and insulating cylinders 11a and 11b arranged on both sides of the metal cylinder 10 in the axial direction.
It is made up of. In the vacuum vessel 1 and at both axial ends of the metal cylinder 10, substantially cylindrical shields 15a and 15 made of non-magnetic stainless steel are provided.
b are provided, and these shields 15a, 1
5b extend toward the insulating tubes 11a and 11b, and are arranged so as to surround the lead rods 2a and 2b.

A coil electrode 5 and a contact electrode 3a are provided at the inner end of the fixed lead rod 2a. The coil electrode 5 is housed inside the metal cylinder 10 forming the vacuum container 1, surrounds the contact electrode 3a, and is provided at the inside end of the movable lead rod 2b. It is provided so as to surround the contact electrode 3b even when it is disconnected (the state shown in FIG. 3).

The structure of the fixed side lead rod 2a, coil electrode 5, and contact electrode 3a will be explained in detail based on FIGS. 4 and 5. The inner end of the lead rod 2a is as follows.
It is formed into a semicircular stepped shape, and has a protrusion 21 and a lower part 2.
2 is formed. The lower part 22 has a recessed hole 23.
A high resistance material (for example, non-magnetic stainless steel,
A spacer 24 made of (Inconel alloy, ceramics) is embedded and connected. On the other hand, the protrusion 21 is directly coupled to the coil electrode 5 to form an electrical structure.

The coil electrode 5 has a slit 5 at one location.
2, the coil body 5 is formed into a substantially cylindrical shape.
1 and both ends 5 in the arc direction of the coil body 51
It is comprised of a pair of arms 55 and 56 extending radially inward from portions 3 and 54 and arranged in parallel. The pair of arms 55 and 56 are connected to the coil body 5.
One end side in the axial direction of 1 (thick wall portion 51b side to be described later)
It is located at the location of

Near the inner end of the one arm 56 and on one surface (upper side in FIG. 4), there is a recessed hole 57 in which the spacer 24 to be interposed when connecting to the lead rod 2a is embedded. It is provided. Also, near the inner end of the other arm 55 and on one surface (lower surface side in FIG. 4)
A recessed hole 58 is provided in which a spacer 35 made of a high-resistance material interposed between the contact electrode 3a and the contact electrode 3a to be described later is embedded and coupled thereto.

The contact electrode 3a is equipped with a connecting body 31 on the back side (the opposite surface that contacts the mating contact electrode 3b).
The end of the connecting body 31 is formed into a semicircular stepped shape, and has a protrusion 32 and a low portion 33 formed therein. The protrusion 32 is connected to one arm 56 of the coil electrode 5.
It is directly connected to the inner end of the wire to form an electric path. Further, the lower portion 33 is provided with a recessed hole 34 in which the spacer 35 interposed between the coil electrode 5 and the other arm 55 is embedded and fixed.

In each figure, reference numeral 59 denotes a reinforcing body for the coil electrode 5, which has a notch 59a corresponding to the slit 52 provided in the coil electrode 5 and is formed in a ring shape. In addition, this reinforcement body 59
is made of non-magnetic stainless steel or Inconel alloy.

However, the most distinctive feature of the present invention lies in the cross-sectional shape of the coil body 51 forming the coil electrode 5. That is, the coil main body 51 is formed to include a substantially cylindrical thin part 51a and a thick part 51b, and has a stepped cross-sectional shape on the inside. The thin portion 51a is connected to a pair of contact electrodes 3.
a and 3b, and the thick part 51b is arranged on the side of the fixed contact electrode 3a (the boundary surface 51c between the thin part 51a and the thick part 51b is on the same level as the surface of the contact electrode 3a). position) or on the back side (the lead rod 2a side). The coil main body 51 is formed such that the cross-sectional center (in other words, the center of gravity) is located within the thick portion 51b, that is, on the back side of the fixed contact electrode 3a.

An example of the dimensional relationship in the cross-sectional shape of the coil body 51 is that the dimensional relationship between the thickness dimension (t) of the thin section 51a and the thickness dimension (T) of the thick section 51b is t≦0.5T, and The relationship between the axial dimension (l) of the thin portion 51a and the opening dimension (G) of the pair of contact electrodes 31a and 31b is l>G. The center of the cross section (center of gravity) of the coil body 51 is the thick part 51
As shown in b, the axial dimension (height dimension) L of the coil body 51 is a predetermined length.

By making the internal cross-sectional shape of the coil body 51 step-like as described above, the current mainly flows through the thick portion 51b due to the shape effect, and the magnetic flux generated by this current flows through the thin portion 51a. It is arranged so that it follows the shape of the inside of the coil body 51, as shown by curve H in FIG. As a result, the magnetic field between the pair of contact electrodes 3a and 3b becomes more parallel to the axial direction than when the coil main body has a simple rectangular cross section, and the magnetic flux density between the contact electrodes is reduced. This is something that can be improved.

Next, to explain the flow of current in the vacuum interrupter configured as described above, if the current enters from the fixed lead rod 2a side, then the lead rod 2a
a flows to one arm 55 of the coil electrode 5 via the protrusion 21 at the lower end, flows to one end 53 of the coil body 51 in the winding direction, flows in a loop shape through the coil body 51, and reaches the other end 54; Next, it reaches the protrusion 32 of the connection conductor 31 via the other arm 56, and also reaches the movable lead rod 2b via the contact electrodes 3a and 3b (via the arc when the wire is broken). An axial magnetic field is generated by a current flowing through the coil body 51 in a loop shape.

As is clear from the above description, the present invention has various effects as described below.

A substantially cylindrical coil electrode 5 is provided to surround the pair of contact electrodes 3a and 3b, and a coil body 51 forming the coil electrode 5 includes a substantially cylindrical thin wall portion 51a and a thick wall portion 51b. Further, a thin wall portion 51a surrounds the pair of contact electrodes 3a and 3b, and a thick wall portion 51b is located on the side or back side of one contact electrode 3a. Since the magnetic field generated by the a○ coil electrode 5 follows the step shape inside the coil body 51, a magnetic field parallel to the axis is obtained, and the magnetic flux density is increased. Therefore, the arc dispersion effect is improved and the shingle cutting performance is improved.

b○ Since the thin wall portion 51a of the coil body 51 surrounds the pair of contact electrodes 3a and 3b, it can be provided close to the contact electrodes 3a and 3b corresponding to the thinner part of the coil body 51. In addition, by increasing the current carrying capacity by increasing the thickness of the thick portion 51b, the coil body 51 can be made smaller in diameter, and as a result, the vacuum interrupter can be made smaller.

Further, the coil electrode 5 is connected to the lead rod 2a on the fixed side.
A pair of contact electrodes 3a, 3 on the fixed and movable sides can be fixed to the inner end of the
b, so even if the movable contact electrode 3b moves during shearing, the magnetic field applied to the arc will not be attenuated, and the shearing performance can be improved.

Since there is no coil electrode on the movable side,
The movable side member is lightweight, requiring only a small operating force during input and disconnection, and the impact force is also small, making it possible to downsize the operating device and improve the durability of the vacuum interrupter.

If a part of the vacuum container 1 is formed by the metal container 10 and the coil electrode 5 is disposed in this part, the vacuum container 1 can be reduced in size in the radial direction.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional vacuum interrupter, FIG. 2 is a perspective view taken along line AA in FIG. 1, and FIG. 3 is a sectional view of a vacuum interrupter according to an embodiment of the present invention.
4 and 5 are an enlarged view and an exploded perspective view of the coil electrode portion of FIG. 3. FIG. 2a, 2b...Lead rod, 3a, 3b...Contact electrode, 5...Coil electrode, 51...Coil body, 51a
... Thin wall portion, 51b... Thick wall portion.

Claims (1)

[Claims] 1. A pair of fixed and movable lead rods 2a and 2, which are equipped with contact electrodes 3a and 3b that can be freely connected and separated at their inner ends.
b, and a coil electrode that generates a magnetic field parallel to the arc generated between the pair of contact electrodes 3a, 3b, the one on the fixed side of the pair of contact electrodes 3a, 3b. A contact electrode 3a is provided electrically separated from the inner end of the lead rod 2a, and the coil electrode 5 is formed into a substantially cylindrical shape with a stepped inner wall side to form a thick part 51b and a thin part 51a, A pair of arms 55 and 56 are provided on the thick wall portion 51b side, extending radially from the center and arranged in parallel, so that the thick wall portion 51b is the main current-carrying portion, and the thin wall portion 51a is used to arc the magnetic flux generated by the thick wall portion. The coil electrode 5 is connected to the pair of contact electrodes 3a, 3b such that the thin wall portion 51a faces the pair of contact electrodes 3a, 3b. One arm 55 of the coil main body 51 is connected to the lead rod 2a, and the other arm 56 is connected to the lead rod 2a.
A vacuum interrupter characterized in that it is connected to the contact electrode 3a.