JP2007188661A - Vacuum valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum valve having a permanent magnet capable of controlling intensity of a vertical magnetic field generated between contacts, and capable of improving a shutoff characteristic. <P>SOLUTION: This vacuum valve is characterized by comprising: a cylindrical vacuum insulation vessel 2; a fixed-side sealing fitting 3 sealed to an opening surface at one end of the vacuum insulation vessel 2; a fixed-side current-carrying shaft 5 piercing through and fixed to the fixed-side sealing fitting 3; a fixed-side contact 6 fixed to an end of the fixed-side energizing shaft 5; a moving-side contact 7 arranged oppositely to the fixed-side contact 6; a moving-side energizing shaft 9 with the moving-side contact 7 fixed to an end thereof; a moving-side sealing fitting 4 having the moving-side current-carrying shaft 9 airtightly movably piercing therethrough and sealed to an opening surface at the other end of the vacuum insulation vessel 2; an insulation layer 13 formed in the outer periphery of the vacuum insulation vessel 2 by molding; and the permanent magnet 15 mounted and fixed to the outer periphery of the insulation layer 13 to cover the vacuum insulation vessel 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vacuum valve having a pair of contact points that can be freely separated from each other, and more particularly to a vacuum valve that can improve a cutoff characteristic.

  Conventionally, a vacuum valve having a pair of contact points that can be contacted and separated has a configuration in which a coil electrode is provided at the contact point and a longitudinal magnetic field (axial magnetic field) is generated between the contact points in order to improve the breaking characteristics. Are known. Thereby, the arc generated between the contacts spreads over the entire contact surface, and damage to the contacts is suppressed (for example, refer to Patent Document 1).

In addition, a configuration is known in which a permanent magnet is attached to an energizing shaft to which a contact is fixed, and a longitudinal magnetic field is generated between the contacts. In this case as well, the arc is diffused and contact damage is suppressed (for example, see Patent Document 2).
Japanese Patent Laid-Open No. 8-111148 (Page 4, FIG. 1) Japanese Patent Laid-Open No. 7-335091 (page 3, FIG. 1)

The above-described conventional vacuum valve has the following problems.
In a vacuum valve provided with a coil electrode at a contact, the path of the main current is formed in a coil shape, which complicates the configuration and lowers the cross-sectional area with respect to the energized current, which is subject to thermal restrictions.

  On the other hand, in a vacuum valve provided with a permanent magnet, the permanent magnet is mounted in the current-carrying shaft, so that the cross-sectional area of the permanent magnet is necessarily restricted. The magnetic force of the permanent magnet is greatly affected by the cross-sectional area, and it has been difficult to generate a sufficient longitudinal magnetic field. The configuration of the contact can be simplified because it is not necessary to generate a longitudinal magnetic field by the contact itself.

  For this reason, there has been a demand for a vacuum valve equipped with a permanent magnet capable of simplifying the contact and capable of controlling the strength of the longitudinal magnetic field generated by the permanent magnet.

  The present invention has been made to solve the above-described problem, and has an object to provide a vacuum valve that includes a permanent magnet that can control the strength of a longitudinal magnetic field generated between contacts, and that can improve a cutoff characteristic. And

  In order to achieve the above object, the vacuum valve of the present invention comprises a cylindrical vacuum insulating container, a fixed-side sealing metal fitting sealed on an opening surface at one end of the vacuum insulating container, and the fixed-side sealing. A fixed-side energizing shaft that is fixed through the metal fitting, a fixed-side contact that is fixed to the fixed-side energizing shaft end, a movable contact that can be separated from and disposed opposite to the fixed-side contact, and the movable side A movable energizing shaft with a contact point fixed to the end, and the movable energizing shaft movably penetrates in an airtight manner and is sealed on the opening surface of the other end of the vacuum insulating container. A metal fitting, an insulating layer formed by molding on the outer periphery of the vacuum insulating container, and a permanent magnet attached and fixed to the outer periphery of the insulating layer so as to cover the vacuum insulating container.

  According to the present invention, the insulating layer is formed on the outer periphery of the vacuum insulating container that houses a pair of contactable and separable contacts, and the permanent magnet is attached and fixed to the outer periphery of the insulating layer. It can be set to a predetermined size, the strength of the longitudinal magnetic field generated between the contacts can be controlled, and the interruption characteristic can be improved.

  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 FIG. FIG. 1 is a cross-sectional view illustrating a configuration of a vacuum valve according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the vacuum valve includes an inner peripheral side contact portion 1 a and an outer peripheral side permanent magnet portion 1 b with respect to the axial direction.

  The contact portion 1a is provided with a cylindrical vacuum insulating container 2 made of, for example, alumina porcelain, and a fixed-side sealing metal fitting 3 and a movable-side sealing metal fitting 4 are hermetically sealed at both end opening surfaces. A fixed-side energizing shaft 5 is airtightly fixed to the fixed-side sealing fitting 3, and a fixed-side contact 6 is fixed to the end of the fixed-side energizing shaft 5 in the vacuum insulating container 2. A concave contact portion 5a is provided at the end of the stationary energizing shaft 5 outside the vacuum insulating container 2, and a stationary outer conductor (not shown) serving as one electric circuit is connected thereto.

  Opposite to the fixed side contact 6, a movable side contact 7 that can be contacted and separated is fixed to the movable side electrode 8. One end of a movable side energizing shaft 9 is fixed to the movable side electrode 8. A cylindrical movable contact conductor 10 is connected in the axial direction to the other end of the movable energizing shaft 9 outside the vacuum insulating container 2 so as to be in sliding contact with a movable outer conductor (not shown) serving as the other electric path. It has become.

One end of a telescopic bellows 11 is airtightly attached to the middle portion of the movable side energizing shaft 9 in the vacuum insulating container 2, and the other end is airtightly attached to the central opening of the movable side sealing fitting 4. Yes. Thereby, it is possible to move the movable-side energizing shaft 9 in the axial direction while maintaining a vacuum level of an internal pressure of 10 ⁻² Pa or less. This movement is performed by an operation mechanism (not shown) connected to the movable contact conductor 10.

  A convex portion 2 a is provided at an intermediate portion of the inner surface of the vacuum insulating container 2, and a cylindrical arc shield 12 provided so as to surround both the contacts 6 and 7 is fixed. By this arc shield 12, metal vapor generated at the time of opening and closing the currents of both contacts 6 and 7 adheres to the inner surface of the vacuum insulating container 2 to prevent a decrease in creeping insulation resistance.

  The permanent magnet portion 1b is provided with an insulating layer 13 formed by molding the outer periphery of the vacuum insulating container 2 or the like with an insulating material such as an epoxy resin. A ground layer 14 formed by applying a conductive paint such as carbon paint or silver paint is provided on the outer periphery of the insulating layer 13. The ground layer 14 may be formed by kneading magnetic powder particles such as iron, nickel, and cobalt in the conductive paint. A cylindrical permanent magnet 15 is provided on the outer periphery of the ground layer 14 so as to surround the entire vacuum insulating container 2. That is, the length of the cylindrical permanent magnet 15 is made longer than that of the vacuum insulating container 2.

  After the insulating layer 13 is formed, the permanent magnet 15 is inserted in advance from the outer periphery on the fixed side of the insulating layer 13, and one end is brought into contact with the protruding portion 13a provided at the movable side end, For example, it is attached and fixed with an epoxy resin adhesive. The aforementioned magnetic powder particles may be kneaded in the same manner. In addition, you may make it the structure which provides the protrusion part 13a in the fixed side so that the permanent magnet 15 may be inserted from the movable side of the insulating layer 13. FIG. In addition, the permanent magnet 15 is magnetized, for example, with an N pole at the top in the figure and an S pole at the bottom in the figure.

  On the fixed side of the insulating layer 13, a cylindrical opening 13b is provided at the center of the end surface, and the fixed-side outer conductor is connected while maintaining insulation performance. A shield electrode 16 for relaxing the electric field is embedded on the movable side of the insulating layer 13. A tapered portion 13c is formed on the end surface, and the movable side outer conductor is connected while maintaining the insulation performance. Such a connection can maintain insulation performance by performing an interface connection through a flexible material.

  Thereby, when both the contacts 6 and 7 are separated and an arc is generated, a DC longitudinal magnetic field (axial magnetic field) is generated between the contacts 6 and 7 by the permanent magnet 15 and the arc becomes a diffusion arc. As a result, an arc spreads over the entire surfaces of both the contacts 6 and 7, local heating can be suppressed, damage to the contacts 6 and 7 can be reduced, and the breaking characteristics can be improved. Since the permanent magnet 15 is attached to the outer periphery of the insulating layer 13, the cross-sectional area can be set to a predetermined size, and a longitudinal magnetic field suitable for the interruption characteristic can be generated.

  Moreover, since the permanent magnet 15 is provided so as to surround the entire vacuum insulating container 2, the longitudinal magnetic field formed in the contact portion 1a can be made further parallel to the axial direction. In addition, the ground layer 14 in which magnetic powder particles are kneaded and the adhesive can make them magnetic, and the magnetic resistance of the magnetic circuit by the permanent magnet 15 can be suppressed. Furthermore, since the permanent magnet 15 is fixed at the ground potential, the electric field distribution of the insulating layer 13 and the like is not disturbed.

  According to the vacuum valve of the first embodiment, the insulating layer 13 is formed on the outer periphery of the vacuum insulating container 2 in which the contactable contacts 6 and 7 are accommodated, and the permanent magnet 15 is attached and fixed to the outer periphery of the insulating layer 13. Therefore, the sectional area of the permanent magnet 15 can be set to a predetermined size, and the strength of the longitudinal magnetic field generated between the contacts 6 and 7 can be controlled. As a result, the arc can be diffused over the entire surfaces of the contacts 6 and 7, and the interruption characteristics can be improved.

  Next, a vacuum valve according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 2 is a cross-sectional view showing a configuration of a vacuum valve according to Embodiment 2 of the present invention. The second embodiment is different from the first embodiment in that a magnetic body is provided in the energizing shaft. In FIG. 2, 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. 2, magnetic bodies 17 a and 17 b such as iron, nickel, and cobalt are attached and fixed inside the fixed-side energizing shaft 5 and the movable-side electrode 8 and the movable-side energizing shaft 9. In these magnetic bodies 17a and 17b, holes are formed in each of the fixed-side energizing shaft 5, the movable-side electrode 8, and the movable-side energizing shaft 9, and the magnetic bodies 17a and 17b are inserted and fixed in the holes. In the case where the movable side electrode 8 and the movable side energizing shaft 9 are integrated, the magnetic body 17 b is attached to a portion excluding the contact 7. The same applies to the fixed side.

  According to the vacuum valve of the second embodiment, a longitudinal magnetic field is easily formed between the contacts 6 and 7, and the interruption characteristic can be improved as compared with the first embodiment.

Sectional drawing which shows the structure of the vacuum valve which concerns on Example 1 of this invention. Sectional drawing which shows the structure of the vacuum valve which concerns on Example 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a Contact part 1b Permanent magnet part 2 Vacuum insulation container 2a Convex part 3 Fixed side sealing metal fitting 4 Movable side sealing metal fitting 5 Fixed side energizing shaft 5a Contact part 6 Fixed side contact 7 Movable side contact 8 Movable side electrode 9 Movable side energization Shaft 10 Movable contact conductor 11 Bellows 12 Arc shield 13 Insulating layer 13a Protruding portion 13b Opening portion 13c Taper portion 14 Ground layer 15 Permanent magnet 16 Shield electrodes 17a and 17b Magnetic body

Claims (3)

A tubular vacuum insulated container;
A fixed-side sealing metal fitting sealed to the opening surface of one end of the vacuum insulating container;
A fixed-side energizing shaft that is fixedly penetrated to the fixed-side sealing fitting;
A fixed-side contact fixed to the fixed-side energizing shaft end;
A movable contact that can be freely separated from and disposed to face the fixed contact;
A movable-side energizing shaft having the movable-side contact fixed to the end;
The movable side energizing shaft penetrates movably in an airtight manner, and a movable side sealing metal fitting sealed to the opening surface of the other end of the vacuum insulating container;
An insulating layer formed by molding on the outer periphery of the vacuum insulating container;
A vacuum valve comprising a permanent magnet attached and fixed to the outer periphery of the insulating layer so as to cover the vacuum insulating container.   2. The vacuum valve according to claim 1, wherein a magnetic body is attached to each of the fixed side energizing shaft and the movable side energizing shaft.   The vacuum valve according to claim 1 or 2, wherein the permanent magnet is attached and fixed with an adhesive kneaded with magnetic powder particles.

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