JP2013125618A - Vacuum valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress an electric field and improve voltage-withstanding characteristics even if brazing filler outflows to a contact and a joint portion of an electrode which generates a magnetic field, and coagulates.SOLUTION: A vacuum valve includes a vertical magnetic field electrode which is fixed to an electric conduction shaft 1 and generates a magnetic field, an electrode like a cup electrode, and a contact 3 jointed to the electrode with brazing filler containing silver as a main component. A joint portion of the electrode to which the contact 3 is jointed is positioned inside of the outer circumference of the contact 3.

Description

  Embodiments of the present invention relate to a vacuum valve having a pair of contact points that can improve withstand voltage characteristics.

  Conventionally, it has been known to use an electrode called a longitudinal magnetic field electrode that generates a magnetic field parallel to an arc to improve the interruption characteristics. In this electrode, the arc spreads over the entire electrode and suppresses generation of abnormal charged particles or generation of metal vapor due to local heating (see, for example, Patent Document 1).

  This type of electrode is shown in FIGS. 4 and 5. The energizing shaft 1 has four arms 2a extending in the radial direction, an arc-shaped coil 2b connected to the tip of the arm 2a, and a coil 2b. A longitudinal magnetic field electrode 2 constituted by a connecting portion 2c having a rectangular cross-section connected to the end of each is fixed. The connecting portion 2c is joined to a disc-shaped contact 3 which is made of a predetermined alloy and can be freely separated and connected by brazing.

  Here, although an appropriate amount of brazing material is used at the joint between the connection portion 2c and the contact 3, the brazing material that is excessive with respect to the joint may flow out and solidify to form the exposed portion 4 on the outer periphery. . Since the brazing material contains silver as a main component, the silver is exposed. Silver has a larger electron emission coefficient than copper, stainless steel and the like used in a vacuum valve, and lowers the withstand voltage characteristic. If the amount of brazing material is small, the formation of the exposed portion 4 can be prevented, but the bonding strength is reduced.

  On the other hand, even if the outer diameter of the electrode is made smaller than that of the contact and a cup-shaped electrode cover is provided on the outer periphery of the electrode so as to cover the above-described joint portion, the withstand voltage characteristic is deteriorated even if the brazing material is exposed from the joint portion. Things that prevent this are known. However, the number of parts increases, making assembly work difficult (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 10-321093 JP2011-96482A

  The problem to be solved by the present invention is a vacuum that can sufficiently suppress the electric field and improve the withstand voltage characteristics even if the brazing material flows out between the contact 3 and the connection part 2c and the exposed part 4 is formed. To provide a valve. In this case, it is assumed that the assembly work can be improved without increasing the number of parts.

  In order to solve the above-mentioned problem, an embodiment of the vacuum valve is a vacuum valve having an electrode that generates a magnetic field fixed to a current-carrying shaft, and a contact that is joined to the electrode by brazing. The bonding portion of the electrode to be bonded is positioned inside the outer periphery of the contact.

Sectional drawing which shows the structure of the electrode of the vacuum valve which concerns on Example 1 of this invention. The top view which shows the structure of the electrode of the vacuum valve which concerns on Example 1 of this invention. FIG. 6 is a half sectional view showing the configuration of an electrode of a vacuum valve according to a second embodiment of the present invention. Sectional drawing which shows the structure of the electrode of the conventional vacuum valve. The top view which shows the structure of the electrode of the conventional vacuum valve.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, a vacuum valve according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a sectional view showing the configuration of the electrode of the vacuum valve according to the first embodiment of the present invention, and FIG. 2 is a top view showing the configuration of the electrode of the vacuum valve according to the first embodiment of the present invention. In addition, the same code | symbol was attached | subjected to the component similar to the past. One of the pair of electrodes will be described.

  As shown in FIGS. 1 and 2, a longitudinal magnetic field electrode 2 is fixed to the energizing shaft 1, and the longitudinal magnetic field electrode 2 is provided at four arms 2 a extending in the radial direction and at the tips of the arms 2 a. The arc-shaped coil portion 2b is connected, and the connecting portion 2c is rectangular in section and connected to the end of the coil portion 2b. The connecting portion 2c is joined to a disc-shaped contact 3 which is made of a predetermined alloy and can be freely separated and connected by brazing. These configurations are the same as in the prior art, and generate a magnetic field parallel to the arc.

  Here, the outer diameter of the connection portion 2 c is slightly smaller than the coil portion 2 b and the contact 3. For this reason, even if the brazing material excess for the joint flows out and solidifies at the joint portion between the connection portion 2 c and the contact point 3 and forms the exposed portion 4, it is formed inside the outer periphery of the contact point 3. The The cross-sectional area of the connecting portion 2c is a size that is not affected by the energization, and the shape thereof may be any of a circular shape, an elliptical shape, a polygonal shape, and the like.

  In general, since the outer diameters of the coil portion 2b and the contact 3 are approximately the same, the electric field of the exposed portion 4 sandwiched between them is sufficiently lowered, and field electron emission is suppressed. For this reason, even if the exposed portion 4 is formed, the withstand voltage characteristic is not deteriorated. In addition, the connection part 2c shall be located inside at least the outer periphery of the contact 3, and may be comparable as the coil part 2b.

  According to the vacuum valve of the first embodiment, the connecting portion 2c of the longitudinal magnetic field electrode 2 is positioned on the inner side of the outer periphery of the contact 3, and is joined by brazing, so that excess brazing material flows out from the joining portion. Even if the exposed portion 4 is formed, the electric field can be sufficiently suppressed and the withstand voltage characteristic can be improved. Further, the number of parts is small, and the assembly work can be facilitated.

  In the first embodiment, the arm portion 2a, the coil portion 2b, and the connection portion 2c of the coil electrode 2 have been described as four sets. However, a plurality of sets can be used, and the strength of the longitudinal magnetic field can be controlled by the number of sets. it can.

  Next, a vacuum valve according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 3 is a half sectional view showing the configuration of the electrode of the vacuum valve according to the second embodiment of the present invention. The difference between the second embodiment and the first embodiment is the configuration of the electrodes. In FIG. 3, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 3, a cup electrode 6 having a plurality of spiral slits 5 on the cup-shaped outer periphery is used. The peripheral part of the cup electrode 6 joined to the contact 3 by brazing is a small diameter part 6 a having an outer diameter slightly smaller than that of the contact 3. In this electrode, current flows in a spiral and generates a magnetic field parallel to the arc.

  According to the vacuum valve of the second embodiment, the same effect as that of the first embodiment can be obtained even in the cup electrode 6 in which the outer diameter of the joint portion is a small diameter portion 6a smaller than the contact 3.

  According to the embodiment described above, even if the brazing material flows out and solidifies at the joint between the electrode and the contact, the electric field can be sufficiently suppressed and the withstand voltage characteristics can be improved.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Current supply axis 2 Longitudinal magnetic field electrode 2a Arm part 2b Coil part 2c Connection part 3 Contact point 4 Exposed part 5 Slit 6 Cup electrode 6a Small diameter part

Claims (3)

An electrode for generating a magnetic field fixed to the energizing shaft;
Contacts joined by brazing to the electrodes;
A vacuum valve having
A vacuum valve characterized in that a joint portion of the electrode to which the contact is joined is positioned inside an outer periphery of the contact. The electrode is a longitudinal magnetic field electrode;
The electrode includes an arm portion fixed to the energizing shaft,
A coil portion connected to the arm portion;
The connection portion is connected to the coil portion,
The vacuum valve according to claim 1, wherein the connection portion is positioned inside the contact. The electrode is a cup electrode;
This cup electrode is a cup-shaped electrode provided with a plurality of slits on the outer periphery,
The vacuum valve according to claim 1, wherein the joint portion has a diameter smaller than that of the contact point.

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