JPS63174232A - Vacuum valve - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a vacuum valve, and particularly to an electrode structure with excellent low surge performance and high current interrupting performance.

(Prior Art) Conventionally, as a vacuum valve considering low surge performance, for example, Japanese Patent Application Laid-Open No. 58-38425 is known. The structure of this vacuum valve is shown in Figures 7, 8 and 9.
As shown in the figure, the openings at both ends of the insulating cylinder 1 are connected to the end plates 2 and 3.
A vacuum container 4 is formed by closing the vacuum container 4, and a pair of electrodes 5 and 6 which can be freely moved toward and away from the vacuum container 4 is disposed inside the vacuum container 4. A movable energizing shaft 8 of the electrode 6 is movably attached to the end plate 3 via a bellows 9, an arc shield 10 surrounding the electrodes 5 and 6 is attached to the insulating cylinder 1, and a bellows cover 11
is attached to the current-carrying shaft 8.

Further, the structure of the electrodes 5 and 6 is such that the opposing contact surfaces are Ag −
Electrode body 14, 1 formed from VC-based sintered material and serving as a contact point
Coil electrodes 16 and 17 are provided on the back surface of the coil electrode 5 and are electrically connected through the current-carrying portions 16a and L7a.

Current from the fixed and movable energizing shafts 7, 8 is shunted into the coil electrodes 16, 17 by the coil shunt arms 16b, 17b, and flows into the coil arc parts 16c, 17c.

The current flowing through the coil arc portions 16c and 17c generates an axial magnetic field in the interelectrode space. This axial magnetic field uniformly spreads the arc ignited between the contacts, minimizing damage to the contacts, making it possible to interrupt larger currents than with flat plate electrodes or spiral electrodes. Furthermore, since the low-surge contact material Ag-VC was used for the contacts 12 and 13, it also had low-surge performance that could suppress the cutting current to below IA.

(Problems to be Solved by the Invention) However, low-surge contact materials such as Ag-w(1) generally have low thermal conductivity and are sintered materials of fine powder of wC. It is weaker against thermal shock than copper or Cu-Cr, and has a relatively small breaking current. Therefore, it has not been possible to obtain an electrode structure that has both low surge performance and large current breaking performance.

The object of the present invention was made in view of the above circumstances, and it is an object of the present invention to provide a vacuum valve having low breaking current characteristics, excellent low surge performance, and excellent large current breaking performance.

[Structure of the invention]

(Means and effects for solving the problem) The present invention has an electrode body and a coil electrode that generates an axial magnetic field inside a vacuum container formed by closing both end openings of an insulating cylinder with end plates. In a vacuum valve in which a pair of electrodes are arranged so as to be able to come into contact with and separate from them, a circular recess is provided on the surface of the electrode body.
An electrode face plate made of a u-Cr material is fixed, a contact made of a low-surge contact material is provided on this electrode face plate so as to protrude by 1 to 3 nn+, and the arrangement relationship between the contact and the coil electrode is adjusted so that the coil electrode generates In order to ensure that the axial magnetic field is weaker on the contact point than on the electrode face plate, a circumferential component due to the coil arc portion of the coil electrode is not formed on the back surface of the contact point and on the radial outside of that back surface. or the arrangement of the contacts and the electrode face plate is such that when a pair of electrodes come into contact, the contact of one electrode contacts the electrode face plate of the other electrode, and has low breaking current characteristics. It has low surge and is capable of interrupting large currents.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. In this embodiment, the general configuration is the same as the conventional one, and both the movable side electrode and the fixed side electrode have the same structure. Therefore, the movable side electrode will be explained, and the explanation of the fixed side electrode will be omitted. Figure 1 is a plan view of the movable side electrode of the vacuum valve of the present invention;
The figure is a cross-sectional view taken along A-0-AM in FIG. 1 and viewed in the direction of the arrow. A coil electrode 22 that generates a directional magnetic field (longitudinal magnetic field), and this coil electrode 2
An electrode body 2 is fixed to the other end of 2 and has a circular recess on its surface (the surface facing the fixed side f!i pole) formed from a Cu material.
3, and an electrode face plate 24 which is fixed to the circular recess of the electrode body 23 by brazing or the like, protrudes at the same level as the surface of the electrode body 23 or slightly more than that, and is made of a Cu-Cr material.
Go, which is fixed to this electrode face plate 24 and whose main component is Ag-VC and which is less than 10 wt% of the total weight as an additive,
It consists of a contact 25 made of Ag-VC contact material containing Ti, Ss, Bi, To, B, etc. in a circular shape with a radius of 5 to 10 mm and protruding from the electrode face plate 24 by 1 to 3+ m. .

Therefore, the coil electrode 22 is integrally fixed to the movable current-carrying shaft 21 by brazing or the like.
d, a plurality of coil shunt arms 22c connected thereto and extending in the radial direction for converting the current flowing through the current-carrying shaft in the radial direction; and one end connected to the tip of each of the coil shunt arms 22c. A coil arc portion 22b that extends in the circumferential direction and generates an axial magnetic field in the space between the electrodes when a current flows through it, and a coil that is connected to the electrode body 22 at the other end of the coil arc portion 22b. It has a connecting portion 22a.

The coil connecting portion 22a of this coil electrode 22 is connected to the electrode body 23.
It is fixed and connected to the back side of. In this case, the outer diameter of the coil electrode 22 is made equal to or smaller than the outer diameter of the electrode body 23. Further, the contact point 25 has a position in the plane shown in FIG. Two or more electrode face plates 24 are arranged on the outside so that they do not protrude, and moreover, a plurality of electrodes are arranged concentrically with the electrode body 23. The coil shunt arm 22 closest to this contact 25
A slit 26 extending linearly in the radial direction at a slight distance from the contact point 25 on the opposite side of the electrode body 23 and the electrode face plate 2
4. The coil connecting portion 22a is fixed to the back surface of the slit 26 on the opposite side from the contact 25, and connects the electrode body 23 and the coil electrode 22. When the movable electrode moves toward the fixed electrode and the two electrodes come into contact, the two electrodes are arranged so that their contact points have contact points with each other.

Note that, if necessary, a reinforcing member (not shown) made of a low conductive material such as stainless steel is fixed between the back surface of the electrode body 23 and the coil electrode 22 to prevent deformation.

Next, the operation of the electrodes of the vacuum valve of the present invention configured as described above will be explained. When a short circuit or ground fault occurs and the rated breaking current flows through the vacuum valve and the movable electrode is separated from the stationary electrode by an operating mechanism (not shown), the cathode is placed on the contact material 25 of the electrode that has become the cathode. The spots are ignited and the metal vapor plasma they produce maintains an arc in the interelectrode space. At this time, an axial magnetic field is generated in the space between the electrodes due to the current flowing through the coil arc portions 22b of the coil electrodes 22 of both electrodes. however,
There is no coil arc portion 22b near the back surface of the contact point 25 of both electrodes, and the current path from the coil connecting portion 22a bypasses the slit 26 provided in the electrode body 23 and the electrode face plate 24 to reach the contact point 25. Therefore, the current flowing near the contact point 25 of both electrodes does not have a circumferential component, that is, the current flowing near the contact point 25 of both electrodes has no circumferential component.
The strength of the axial magnetic field at and around SU 5 is weaker than that at SU. For an arc ignited on an electrode with a weak axial magnetic field, when the instantaneous value of the arc current increases, the arc voltage increases and becomes unstable, as shown in Figure 3, and the arc is ignited only on the contact point 25. As a result, the cathode spot partially moves onto the surrounding electrode face plate 24 made of Cu-Cr material. When an arc is ignited on the electrode face plate 24, the axial magnetic field strength there is sufficiently strong to produce an arc voltage near the minimum value in FIG. 3, and the arc voltage is sufficiently low to stabilize the arc. At this time, in order to keep the voltage between the electrodes balanced, the current share increases in the area where the arc voltage is low, and most of the arc moves onto the electrode face plate 24, reducing contact wear to maintain the large current arc at the contact 25. contact damage is reduced. As is well known, Cu-C
Since the R material has large current interrupting performance and is a high withstand voltage contact material, the interrupting performance is further improved by combining it with a vertical magnetic field electrode, so the electrode structure of the present invention has a damage reduction effect of low surge contact material. In combination with this, it becomes an electrode structure with high capacity breaking performance.

In the case of interrupting a current such as a steady load current, the axial magnetic field strength in the entire interelectrode space is weak, the arc voltage difference between the contact 25 and the electrode face plate 24 is small, and the contact 2
Since the contact point is between 5 and 5, the arc is ignited mainly on the contact point until the load current is cut off at the current zero point. here,
The contact 25 contains Ag-VC or a small amount of Se, Bi,
Since it uses a metal material whose main component is Ag-VC containing low melting point materials such as B and Te, it exhibits low interruption performance with an average cutting current of approximately 0.8 amperes or less, and has low surge vacuum resistance. This results in an electrode structure that makes it possible to realize a valve.

By containing 10vt% or less of CO or Ti in the contact 25, the bonding force between fine particles of the wc compound in the metal structure of the contact 25 is strengthened, suppressing arc damage to the contact and interrupting large currents. advantageous to

By subjecting the electrodes constructed in this way to current aging, a thin film layer of fine particles of Ag, Cu, and Cr is formed on the opposing surfaces of the electrodes, resulting in effects such as lowering the welding pull-off force and increasing withstand voltage. is possible.

According to the above configuration, due to the effect of having a contact point between the Cu-Cr material, the axial magnetic field and its strength distribution, and the contact whose main component is Ag-VC, the Cu-Cr
By increasing the current sharing on the electrode face plate made of Ag-V
It is possible to minimize damage caused by large current interruption to the C contact, and it is also possible to ignite an arc on the Ag-νC contact when the current is small, improving the interruption performance and reducing the average rupture. It becomes possible to provide a vacuum valve having low surge performance with a current of 0.8 A or less.

Note that the present invention is not limited to the above-described embodiments, and the contact 25 is made of a low-surge material made of an alloy containing a high vapor pressure, low melting point material based on Ag or Cu, and Similar effects can be achieved in a vertical magnetic field electrode in which the electrode face plate 24 is made of a Cu-Cr material, and a vacuum valve with improved cutoff performance and low surge performance can be provided. It may also be configured to have a contact point between the contact point and the electrode face plate, i.e., as shown in FIGS. 4 and 5.
In the figure, the movable side electrode 30 has one end fixed to the end of the movable current-carrying shaft 31, one or more coil electrodes 32 that generate an axial magnetic field, and the other end of the coil electrode 32 fixed to the coil electrode 32, which is made of Cu material. An electrode body 33 is formed from a metal material and has a circular recess on the back surface (the surface facing the fixed electrode).

The electrode body 33 is fixed to the circular concave portion with a brazing rod or the like.

The electrode face plate 34 is made of a Cu-Cr material and protrudes from the surface of the electrode body 33 at the same level or slightly more than the surface of the electrode body 33. Go, Ti below 10wt%
.

Ag containing Se, Bi, Te, B, etc.
Formed into a circle with a radius of 5 to 10 m+ from VC type contact material,
Contact 3 protrudes 1 to 3 Im from the electrode face plate 34
It consists of 5 parts. Here, the coil electrode 32 is connected to the movable energizing shaft 31 via a coil connecting portion 32a extending linearly in the radial direction, and connected to the electrode body 33 via a coil arc portion 32b.
They are configured to be electrically connected to each other via coil current-carrying portions 32c provided at the ends of the coils, and the outer diameter thereof is approximately the same as the outer diameter of the scraping body 33. Further, when the radius of the electrode body 33 is R, three to four contacts 35 are equally spaced and provided at positions R/2 or more outward from the center.

On the other hand, the fixed side electrode 40 also has the same configuration as the above-mentioned movable side electrode 30, and as shown by the dashed line in FIG.
a single or plural coil electrodes 32 having one end fixed to the end of the coil electrode 32; an electrode body 33 fixed to the other end of the coil electrode 32; an electrode face plate 34 fixed to a circular recess of the electrode body 33; The electrode face plate 34 is fixed to the electrode face plate 34, and when the radius of the electrode body 33 is R, 3 to 4 pieces are equally spaced at positions outside R/2 or more from the center.
The contact point 35 is provided to protrude 1 to 3 m from the contact point 4.

Therefore, when the movable side electrode 30 and the fixed side electrode 40 are disposed facing each other in the vacuum container, the positional relationship of the respective contacts 35 is as shown in FIGS. 5 and 6. The contacts 35 of the fixed electrode 40 are located at the positions shown by solid lines, while the contacts 35 of the fixed electrode 40 are located at positions shifted from each other so that they are located at the positions shown by dashed lines.

Therefore, the movable side electrode 3 is
0 is injected toward the fixed side electrode 40, each other's A
g-Contacts 35 with VC as the main component and protruding 1 to 3 m from the others with a radius of 5 to 10 nws do not contact each other, and the contacts 35 with Ag-WC as the main component and Cu-Cr
The electrodes are arranged such that the electrode face plate 34 has a contact point. In addition, in this case as well, the contact 35 is made of Ag-WC.
An Ag-VC type contact material is used which contains Co, Ti, Se, Bi, Ten B, etc. as a main component and 10vt% or less of the total weight as additives. The electrode body 33 and the electrode face plate 34 are provided with a plurality of slits 36 extending linearly in the radial direction. Further, on the back surface of the electrode body 33, a reinforcing material 37 made of a material with low conductivity such as stainless steel is fixed between the reinforcing material 37 and the coil electrode 32.

In the electrode configured as described above, when the movable side electrode 30 is separated from the fixed side electrode 40 by an operation mechanism (not shown) in order to cut off a current with a rated current of several thousand amperes or less, mutual Ag - Contact 35 whose main component is VC
Since there was a contact point between the electrode face plate 34 made of Cu-Cr, the contact point 35 of the electrode which became a cathode and the electrode face plate 3
Cathode spots are ignited on both sides of 4, and the metal vapor plasma generated by these spots maintains the arc up to near the current zero point.

Here, the cutting current value is determined by the metal material used for the cathode spot, and Cu-Cr is approximately 3.5 amperes, whereas Ag-VC containing low melting point materials such as Se, Bi, Te, and B is approximately 3.5 amperes. A metal material containing as a main component exhibits a low breaking current characteristic of about 0.8 ampere or less.

Therefore, the contact point 35 of the electrode that has become a cathode and the electrode face plate 3
Among the cathode spots fired on both sides of 4, Ss
, B, L, A containing low melting point materials such as Tet B
The one ignited on the contact 35 whose main component is g-WC is
Since the current is maintained close to the zero point, it is possible to realize a low surge vacuum valve with a low breaking current characteristic by using such an electrode structure. In addition, if a phase-to-phase short circuit or a ground fault occurs and the rated breaking current of the opposing ampere is cut off, if the movable electrode 30 is separated from the fixed electrode 40 by an operation mechanism (not shown), the mutual A
Since there was a contact point between the contact point 35 mainly composed of IC-VC and the electrode face plate 34 made of Cu-Cr, a cathode spot was ignited on both sides of the electrode contact point 35 which became a cathode and the electrode face plate 34. The metal vapor plasma generated by these maintains the arc up to near the current zero point.

Furthermore, it is known that by combining a longitudinal magnetic field electrode with a coil electrode 32, the arc can be diffused in the interelectrode region even at a relatively large current value.
Since the structure has a contact point between the contact point 35 mainly composed of -VC and the electrode face plate 34 made of Cu-Cr, damage caused by melting at the contact point 35 of the electrode serving as the anode is slight.

Moreover, the thermal conductivity is small and the cathode spot is weak.
It is easy to concentrate on the C contact < llIC on the Ag-WC contact
Although cathode damage is severe due to scattering of particles, the bond between carbon particles is strengthened by containing 10 wt% or less of CO or Ti and dissolving it in solid carbon.

Cathode damage can be reduced. With this electrode structure having both of these effects, it is possible to provide a vacuum valve that has low surge and is capable of interrupting large currents.

The plurality of linear slits extending in the radial direction provided in the electrode body 33 and the electrode face plate 34 can prevent eddy currents flowing through the electrode body 33 and effectively generate an axial magnetic field.

A reinforcing material 3 made of a low conductivity material such as stainless steel is fixed between the opposing back surface of the electrode body 33 and the coil electrode 32.
6 can prevent deformation of the electrode body 33 and coil electrode 32 when the vacuum valve is opened and closed @1.

By subjecting the electrode constructed in this manner to current aging, Ag and Cu are formed on the opposing surfaces of the electrode body 33.

By forming a thin film layer of fine Cr particles, it is possible to obtain effects such as a reduction in welding and tripping, and an increase in pressure resistance.

According to this example, the effect of having an axial magnetic field and a contact point between the Cu-Cr electrode face plate and the Ag-1c contact,
When a large current g is cut off, the current is shared more on the Cu-Cr electrode face plate, making it possible to minimize the damage caused by the large current cutoff of the g-vc contact, and when the current is small, the AR
- Since it is possible to ignite an arc on the VC, it is possible to improve the breaking performance and provide a vacuum valve having low surge performance with a breaking current of 0.8 A or less.

Furthermore, in a vertical magnetic field electrode, the contact 35 is made of a low-surge material made of a sieve or a Cu-based alloy containing a high vapor pressure, low melting point material, and the surrounding electrode face plate 34 is made of a Cu-Cr material. It is also possible to provide a vacuum valve that exhibits similar effects and has improved shutoff performance and low surge performance.

〔Effect of the invention〕

Since the present invention is configured as described above, it has both a low-surge contact material and Cu-Cr having good breaking performance, has a contact point between the low-surge contact and the Cu-Cr material, and has a vertical magnetic field electrode. Since the vacuum valve has a low surge performance and an arc diffusion effect on Cu-Cr during large current interruption, it is possible to provide a vacuum valve with low surge and large interruption capacity.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing one embodiment of the electrode structure of the vacuum valve of the present invention, FIG. 2 is a sectional view taken along line A--A in FIG. The figure shows C related to the present invention.
Fig. 4 is a diagram showing the relationship between the axial magnetic flux density and arc voltage of u-Cr material and Ag-WC material; Fig. 4 is a partially cutaway plan view showing the electrode structure of another embodiment of the present invention; Figure 5 is a cross-sectional view taken along line A-○-A in Figure 4 and viewed in the direction of the arrow;
FIG. 6 is an explanatory diagram showing the arrangement of electrodes in another embodiment of the present invention, and FIG. 7 is a sectional view showing the structure of a conventional vacuum valve.
FIG. 8 is a partially cutaway plan view showing the electrode structure of a conventional vacuum valve, and FIG. 9 is a cross-sectional view taken along A-0-AAli in FIG. 8 and viewed in the direction of the arrow. 4... Vacuum container, 21... Movable current-carrying shaft 22.
...Coil electrode, 23...Electrode body 24...Electrode face plate, 25...Contact 26...Slit (8733) Representative patent attorney Yoshiaki Inomata (and 1 other person) 1st rsn Figure 2 3 Illustration 4I! 1 6th ω 7th figure

Claims (8)

[Claims] (1) A vacuum in which a pair of electrodes having an electrode body and a coil electrode that generates an axial magnetic field is arranged so as to be able to be moved toward and away from the inside of a vacuum container formed by closing the openings at both ends of an insulating cylinder with end plates. In the bulb, a circular recess is provided on the surface of the electrode body to which an electrode face plate made of a Cu-Cr material is fixed, and a disc-shaped contact made of a low-surge contact material is made to protrude from the electrode face plate by 1 to 3 mm. A vacuum valve characterized by being provided with. (2) The low-surge contact material contains sintered Ag-WC as the main component, and contains Co, Ti, Se, Bi, Te, etc. in a weight ratio of 10 wt% or less without impairing its low breaking current characteristics.
The vacuum valve according to claim 1, which contains B or the like. (3) The contact points should not protrude beyond the electrode face plate and should be arranged at the center or on concentric circles, and the axial magnetic field generated by the coil electrode should have a weaker strength on the contact point than on the electrode face plate. Claim 1: The coil electrode and the contact are arranged such that the circumferential component of the current due to the coil arc portion of the coil electrode is not formed on the back surface of the contact and on the radially outer side of the back surface. Vacuum valve as described in section. (4) The vacuum valve according to claim 2, wherein the electrode face plate and the electrode body are provided with one or more slits extending in the radial direction between the coil arm portions of adjacent coil electrodes and the coil connecting portions. (5) The contacts should not protrude beyond the electrode face plate and should be placed in the center or on concentric circles, and when the vacuum valve is turned on and the movable electrode contacts the fixed electrode, the contact of one electrode will be placed on the electrode face plate of the other electrode. Claim 1 is characterized in that the contact point electrically connected to the contact point and the electrode face plate are arranged.
Vacuum valve as described in section. (6) The vacuum valve according to claim 5, wherein the electrode face plate and the electrode body are provided with one or more slits extending linearly in the radial direction. (7) The vacuum valve according to claim 5, wherein a ring-shaped reinforcing material made of a low conductivity material such as stainless steel is provided between the back surface of the electrode body and the coil electrode. (8) The vacuum valve according to any one of claims 1 to 6, wherein the vacuum valve is provided with an electrode having a contact, an electrode face plate, and a coil electrode, and is subjected to current aging.