JPS6319971B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vacuum interrupter, and more particularly to a vacuum interrupter capable of applying an effective magnetic field parallel to an arc.

Conventionally, vacuum interrupters have been provided that apply a magnetic field parallel to the arc (axial magnetic field) for the purpose of improving shearing performance, and the coil for generating the magnetic field can be moved in and out to generate the arc. Generally, each electrode is provided on the back of a pair of electrodes.

An example of a conventional vacuum interrupter of this type that applies an axial magnetic field is shown in FIG. In the figure, 1 is a vacuum container, 2 is a fixed lead rod, 2a is a movable lead rod, 3 and 3a are fixed and movable arc electrodes with a contact part in the center, 4 and 4a
are coil electrodes that generate an axial magnetic field, and are provided at the ends of the fixed and movable lead rods 2 and 2a, respectively, and are connected to the backs of the fixed and movable arc electrodes 3 and 3a via connecting fittings 4b. It is connected to the.

Although not shown, the coil electrodes 4 and 4a generally consist of a plurality of arms positioned in the radial direction and an arcuate portion having one end connected to the outer end of each arm. And the inner end of each arm (end in the extending direction)
is connected to each arc electrode 3, 3 via the connection part 4b.
This is connected to the back of a, thereby changing the current in a loop between the lead rod and the contact, thus generating an axial magnetic field.

In addition, in the figure, 5 is a bellows, and 6 is a shield.

By the way, in the conventional vacuum interrupter as described above, a coil electrode for generating an axial magnetic field is provided behind the arc electrode.

However, according to this configuration, the coil electrodes 4, 4
Since a is located at a distance from the arc,
Coil electrodes 4, 4a to one arc electrode 3, 3a
It is difficult to apply a linear magnetic field to the arc if it is provided only on the back of the arc electrode, and the magnetic field will be curved on the other arc electrode side. As a result, an effective axial magnetic field is not applied to the arc, resulting in a problem that the arc dispersion effect is weakened and the arc is concentrated.

Therefore, as mentioned above, the coil electrodes 4, 4a are placed on both sides of the arc.
They are respectively provided on the backs of a pair of arc electrodes 3, 3a, and form a magnetic field between both coil electrodes 4, 4a to generate an effective axial magnetic field, thereby preventing the arc from concentrating. It is composed of

However, a pair of arc electrodes 3 separated from each other,
Since the coil electrodes 4, 4a are provided on the back of the movable arc electrode 3a, the coil electrode 4a provided on the back of the arc electrode 3a on the movable side moves when the arc electrode 3a is disconnected, and the pair of arc electrodes 3, 3a, the magnetic field applied to the arc will gradually attenuate, and due to the attenuation of the magnetic field, the dispersed arc will become concentrated at the end of the shearing stage, and it will become impossible to shatter it. There was a problem.

For this reason, there is a limit to the improvement in shearing performance by a vacuum interrupter in which a pair of arc electrodes 3, 3a that move apart are provided with coil electrodes 4, 4a, respectively.

Furthermore, providing the coil electrodes 4 and 4a on the backs of the pair of arc electrodes 3 and 3a increases the number of parts and joints (brazing), which leads to problems such as poor durability. In particular, since the movable side is provided with the coil electrode 4a, the amount of movability increases, resulting in a problem of increased impact and decreased durability.

An object of the present invention is to provide a vacuum interrupter with improved shearing performance by solving the above-mentioned problems in a vacuum interrupter of the type that applies an axial magnetic field.

An embodiment of the present invention will be described below based on the drawings.

FIG. 2 shows a vacuum interrupter of the present invention corresponding to FIG. 1, and the same parts are designated by the same reference numerals. The first characteristic configuration of the present invention is
A coil electrode 7 for generating an axial magnetic field is provided on the fixed side lead rod 2, and this coil electrode 7 is a cylindrical body that surrounds both the fixed side arc electrode 3 and the movable side arc electrode 3a. be. That is, the coil electrode 7 is made of a highly conductive material, and as shown in FIG. A pair of extending arm parts 71 and 72 are provided, and conductive parts 71a and 72a are provided at the inner ends of the arm parts 71 and 72 to connect the fixed side lead rod 2 and the fixed side arc electrode 3. ing.

Concave portions 73 and 74 are provided on both sides of the conductive portions 71a and 72a in the axial direction (both upper and lower sides in the figure), and in the concave portion 74 on the lower side in the figure of one of the conductive portions 71a, High resistance spacer 1
A small hole 76 into which 0a is inserted is provided. Also, a recess 73 on the upper side in the figure of the other conductive portion 72a
There is a small hole 75 into which the high resistance spacer 10 is inserted.
is provided.

On the other hand, as shown in FIG. 4, the coil electrode 7
The tip (lower end) 21 of the fixed-side lead rod 2 that is connected to the upper side in the figure of the conductive portions 71a and 72a is formed in a semicircular stepped shape, and the tip 2 that protrudes
2 is inserted and coupled into the recess 73 of one conductive part 71a of the coil electrode 7, and the high resistance spacer 1 is inserted into the small hole 75 bored in the other conductive part 72a of the stepped part 23.
0.

The high-resistance spacer 10 is made of a low-conductivity material such as stainless steel or Inconel, and has a small hole 24 provided in the stepped portion 23 of the fixed lead rod 2 and a conductive portion 73 of the coil electrode 7. The coil electrode 7 and the fixed lead rod 2 are integrated by insertion into the small hole 75.

Further, an arc electrode 3 is coupled to the lower side of the conductive portions 71a and 72a of the coil electrode 7 in the figure, and the arc electrode 3 is provided with a connecting shaft 33 having a protrusion 31 and a stepped portion 32. There is. This connecting shaft 33
In the figure, the protrusion 31 is inserted and coupled into the recess 74 on the lower side in the drawing of one of the conductive parts 72a, and the step part 32 is connected to the high resistance spacer 10a embedded in the small hole 34 provided in the step part 32. The coil electrode 7 and the arc electrode 3 are integrated by being inserted into a small hole 76 provided in the recess 74 of the conductive portion 71a and coupled. In addition,
The high resistance spacer 10a is the above-mentioned high resistance spacer 1.
It is made of the same material as 0. The coil electrode 7 is made of a highly conductive material, such as copper, copper alloy, gold, silver, or gold-silver alloy.

As a second characteristic configuration of the present invention, a reinforcing plate 11 is provided on the upper part of the coil electrode 7 in the figure, and a floating shield 60 is provided at a constant distance from the inner peripheral surface of the coil electrode 7. be done.

As shown in FIG. 3, the reinforcing plate 11 is a disc-shaped body 11a having a diameter equal to the diameter of the coil electrode 7.
It has an opening 11b and a circular hole 11c that expose the arm portions 71, 72 and conductive portions 71a, 72a of the coil body 7. This disc-shaped body 11a
is made of high resistance or low conductivity material such as stainless steel or Inconel. The disk-shaped body 11a and the coil electrode 7 are fixed together by brazing.

Note that the disc-shaped body 11a is connected to the coil electrode 7 so that there is a gap between the inner peripheral edge of the opening 11b and the circular hole 11c, the arm parts 71 and 72, and the conductive parts 71a and 72a.
sticks to.

On the other hand, as shown in FIG. 2, the floating shield 60 is a substantially inverted funnel-shaped body fixed to the lower part of the cylindrical intermediate support 6a between the shields 6, 6 at an intermediate potential by brazing or the like. It will be done. floating shield 60
The cylindrical portion 61 surrounds the arc electrodes 3, 3a at a constant interval. It goes without saying that the floating shield 60 is made of a high resistance or low conductivity material such as stainless steel or Inconel.

To explain the flow of current in the vacuum interrupter configured as above, the current in the fixed lead rod 2 is conducted to the arm portion 71 via one conductive portion 71a, and forms a loop in the cylinder body 9. , flows to the connecting shaft 33 via the other arm portion 72 and the conductive portion 72a, reaches the arc electrode 3, and conducts to the movable lead rod 2a via the other side arc electrode 3a, The cylinder body 9
This generates an axial magnetic field when it flows in a loop.

Next, another embodiment shown in FIG. 5 will be explained.
In this example, a cup shield 12 made of a high-resistance material is mounted on the upper part of the floating shield 60 in the figure.
On the other hand, the reinforcing body 11 of the coil electrode 7 is not shaped like a disk, but has a substantially star shape as shown in FIG. The reinforcing body 11 is an annular body 11e having a radial support arm 11d that is coupled to the coil electrode 7 by brazing or the like, and has an opening 11b. On the other hand, the cup shield 12 is a cylindrical body with a bottom, and is brazed to the tip 21 of the fixed lead rod 2 or brazed to the reinforcing body 11 to be suspended so as to cover the upper opening of the floating shield 60 in the figure. be done. The cup shield 12 is arranged at a predetermined interval without contacting either the coil electrode 7 or the floating shield 60.

Therefore, according to this embodiment, since the coil electrode 7 is almost completely shielded from the arc electrode 3a by the cup shield 12 and the floating shield 60, it is possible to not only improve the dielectric strength but also strengthen the coil electrode 7. The generation of eddy current that may occur in the body 11 is suppressed to an extremely small amount by the support arm 11d.

As is clear from the above description, in the vacuum interrupter according to the present invention, the coil electrode 7 surrounding both the fixed and movable arc electrodes 3 and 3a is connected to the fixed lead rod 2 and the fixed arc electrode. 3
Since it is connected between the two, it brings about various effects as described below.

Since the coil electrode 7 is fixed and surrounds both the fixed and movable arc electrodes even when the sheath is cut off, even if the movable arc electrode 3a moves when the sheath is cut off, the arc The magnetic field applied to the magnet is not attenuated, and the shearing performance can be improved.

Since the coil electrode 7 is formed long in the axial direction and has a large electric circuit cross-sectional area, the problem of heat generation does not occur.

Since there is no coil electrode on the movable side,
The movable side member is lightweight, and since the operating force required for turning on and off is small, and the impact force is small, it is possible to downsize the operating device and improve the durability of the vacuum interrupter.

Since the arc electrodes 3, 3a can be substantially completely shielded by the floating shield 60 and the cup shield 12, no flashover occurs between the coil electrode 7 and the arc electrode 3a, and therefore the dielectric strength increases significantly. For this reason, the arc electrode 3a
It is clear that the horizontal distance between the coil electrode 7 and the coil electrode 7 can be shortened, resulting in a reduction in the diameter of the coil electrode 7.

The reinforcing body 11 of the coil electrode 7 is annular body 1 in order to prevent the generation of eddy current that may occur due to the disk shape.
If it is mounted in a substantially star shape with supporting arms 11d radiating from 1e, the influence of eddy currents on the magnetic field generated by the coil electrode 7 can be minimized to a negligible level.

[Brief explanation of the drawing]

Fig. 1 is a central vertical cross-sectional view showing a conventional vacuum interrupter that applies an effective magnetic field parallel to the arc, Fig. 2 is a vertical central cross-sectional view of a vacuum interrupter according to the present invention, and Fig. 3 is an assembly of the main parts of the coil body. FIG. 4 is a perspective view showing the relationship between the lead rod on the fixed side and the center conductive portion of the coil body; FIG. 5 is a vertical sectional view showing another embodiment of the present invention; FIG. The figure is a perspective view showing another example of the reinforcing body. DESCRIPTION OF SYMBOLS 1... Vacuum container, 2, 2a... Fixed and movable side lead rod, 3, 3a... Arc electrode, 6... Shield, 7... Coil electrode, 11... Reinforcement body, 12
...Cup shield, 60...Floating shield.

Claims (1)

[Claims] 1 Coaxially attaching a coil electrode 7 that generates an effective magnetic field parallel to the arc to the fixed lead rod 2, attaching the fixed arc electrode 3 to the coil electrode 7 coaxially with the fixed lead rod 2, Inside the coil electrode 7, the fixed side arc electrode 3
A movable arc electrode 3a facing the movable lead rod 3a on the same axis and capable of moving toward and away from the movable lead rod 2a is attached to the movable lead rod 2a. A vacuum interrupter characterized by being provided with a floating shield 60 that surrounds the electrodes 3 and 3a and covers the inner peripheral surface of the coil electrode 7.