JP5597116B2 - Vacuum valve - Google Patents

Description

  The present invention relates to a vacuum valve configured to drive an arc by a magnetic field generated by a current flowing through an electrode.

  The vacuum valve generally forms an airtight container by sealing both ends of an insulating cylinder made of ceramic or glass with a fixed end plate and a movable end plate. A fixed-side electrode plate joined with a fixed-side electrode is supported and fixed on the fixed-side end plate, and a movable-side electrode is disposed so as to face the fixed-side electrode, and the movable-side electrode rod is connected to this. The movable side electrode rod and the movable side end plate are hermetically connected via a bellows-shaped bellows, and the movable side electrode and the movable side electrode rod can be operated while maintaining the vacuum in the vacuum valve. Further, an arc is generated between the electrodes when the current is interrupted, and the metal vapor is scattered from the electrodes, so that it adheres to the inner surface of the insulating cylinder and deteriorates the insulating performance on the inner surface. An arc shield is provided around the electrode to suppress the contamination of the inner surface of the insulating cylinder.

  When interrupting a large current exceeding several tens of kA, there is a spiral structure electrode as one means for improving the interrupting performance. A spiral groove is provided in the electrode, and a driving force for rotating the outer periphery of the electrode in the circumferential direction is generated by the action of a magnetic field and an arc current generated by current flowing through the spiral blade portion. By rotating the arc, local heating of the electrode surface is suppressed and the interruption performance is improved. The spiral blade portion has an elongated shape and a relatively low strength, and when the opening / closing operation force is large, the spiral blade portion is deformed, resulting in a decrease in the breaking performance and the withstand voltage performance. As a countermeasure, a disk-shaped reinforcing plate or a ring-shaped reinforcing ring is fixed to the back of the electrode. Generally, austenitic stainless steel, which has high mechanical strength and high electrical resistance, is used, and is fixed to the back of the electrode by brazing. .

Japanese Patent Laid-Open No. 2001-52576 (FIGS. 1 to 3 and description thereof) JP-A-1-105428 (FIG. 1 and its description)

  In the conventional vacuum electrode structure vacuum valve, there is a limit to the strength of the magnetic field generated to rotate the arc and suppress local overheating of the electrode surface. In order to further reduce the diameter of the electrode, there is a problem that the magnetic field intensity generated by the spiral electrode having a reduced diameter must be increased.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to make it possible to obtain a magnetic field strength necessary for driving an arc with respect to a reduction in the diameter of an electrode. .

In the vacuum valve according to the present invention, a pair of electrodes are supported in a vacuum container so as to be able to contact and separate, and a magnetic field due to a current flowing through the electrodes is generated between one electrode and the other electrode of the pair of electrodes. In a vacuum valve in which arms extending in the circumferential direction so as to drive an arc are formed on the electrode, the current flowing to the surface of the electrode opposite to the surface facing the counterpart electrode is limited to limit the current of the electrode. A vacuum valve in which a current limiting structure for biasing a current flowing through the arm portion toward the facing surface is provided on the side opposite to the facing surface , wherein the current limiting structure is a surface opposite to the facing surface of the electrode. It is a vacuum valve characterized by being a hollow part provided in the central part .

In the present invention, a pair of electrodes are supported in a vacuum container so as to be able to contact and separate, and a magnetic field generated by a current flowing through the electrodes drives an arc generated between one electrode and the other electrode of the pair of electrodes. Thus, in a vacuum valve in which arms extending in the circumferential direction are formed on the electrode, the current flowing on the surface of the electrode opposite to the surface facing the counterpart electrode is limited and flows through the arm portion of the electrode. A vacuum valve provided with a current limiting structure for biasing current toward the opposing surface on the side opposite to the opposing surface , wherein the current limiting structure is provided at a central portion of the surface opposite to the opposing surface of the electrode. Since the recess is provided, there is an effect that the magnetic field intensity necessary for driving the arc can be obtained with respect to the reduction in the diameter of the electrode.

It is a figure which shows Embodiment 1 of this invention, and is sectional drawing which shows an example of a structure of a vacuum valve. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows Embodiment 1 of this invention, (a) is a top view of a fixed side electrode, (b) is sectional drawing of a fixed side electrode, (c) is a bottom view of a fixed side electrode. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows Embodiment 1 of this invention, (a) is an upper surface perspective view of a fixed side electrode, (b) is a lower surface perspective view of a fixed side electrode. 4A and 4B are diagrams showing Embodiment 2 of the present invention, in which FIG. 5A is a top view of a fixed side electrode, FIG. 5B is a cross-sectional view of the fixed side electrode, and FIG. It is a figure which shows Embodiment 2 of this invention, (a) is an upper surface perspective view of a stationary-side electrode, (b) is a lower surface perspective view of a stationary-side electrode. FIG. 5 is a diagram illustrating a second embodiment of the present invention, in which (a) is a top view of another modification of the fixed electrode, (b) is a cross-sectional view of another modification of the fixed electrode, and (c) is a fixed side. It is a bottom view of the other modification of an electrode. It is a figure which shows Embodiment 2 of this invention, (a) is an upper surface perspective view of the other modification of a stationary side electrode, (b) is a lower surface perspective view of the other modification of a stationary side electrode.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to FIGS. 1 is a cross-sectional view showing an example of the configuration of a vacuum valve, FIG. 2 (a) is a top view of a fixed-side electrode, FIG. 2 (b) is a cross-sectional view of the fixed-side electrode, and FIG. FIG. 3A is a bottom view, FIG. 3A is a top perspective view of the fixed electrode, and FIG. 3B is a bottom perspective view of the fixed electrode.

  In the figure, 1 is an insulating cylinder made of alumina ceramics, 2 is a fixed side end plate that covers one end opening of the insulating cylinder 1, and 3 is a movable side end that covers the other end opening of the insulating cylinder 1. The fixed and movable side end plates 2 and 3 are coaxially attached to the end surface of the insulating cylinder 1 by brazing. 4 is a fixed side electrode rod brazed to the fixed side end plate, 11 is a fixed side electrode brazed to the fixed side electrode rod, and 12 is a movable side electrode disposed facing the fixed side electrode 5. , 7 is a movable electrode bar brazed to the movable side electrode 12, and 6 is a bellows made of, for example, thin stainless steel in a bellows shape and arranged so that the movable side electrode bar 5 can move while maintaining vacuum airtightness. The bellows 6 allows the fixed side electrode 11 and the movable side electrode 12 to contact and separate while maintaining vacuum airtightness. The arc shield 7 is disposed so as to surround the periphery of the fixed electrode 11 and the movable electrode 12 in order to suppress the amount of metal vapor caused by the arc generated between the electrodes when the current is interrupted from adhering to the inner surface of the insulating cylinder 1. ing.

  Reinforcing plates 15 are joined to the back surfaces of the opposed surfaces of the fixed side electrode 11 and the movable side electrode 12 by brazing, and are also joined to the fixed side electrode rod 3 and the movable side electrode rod 5, respectively. This prevents the electrode from being greatly deformed and broken due to the impact when it is mounted on the circuit breaker during the closing operation.

  The fixed side electrode 11 and the movable side electrode 12 are spiral electrodes as one of effective electrode structures for interrupting a large current exceeding several tens of kA, and a spiral blade 13 is formed by a spiral groove 11a. FIG. 2 shows an example of a spiral electrode having four spiral blades 13. Since the fixed side electrode 11 and the movable side electrode 12 are symmetrical with respect to the surface at the intermediate position of the opposing surface, the fixed side electrode will be described. The fixed-side electrode 11 has a shape in which the opposite-surface-side center portion between the electrodes is recessed in a circular shape, and the diameter of the center-recessed portion 11b is φB and the depth is t1. Further, a recess 11c is provided in the center on the side opposite to the opposing surfaces of the electrodes (hereinafter referred to as the electrode back), and the diameter of the recess 11c is φC and the depth is t2. 11 d is a contact portion between the fixed side electrode 11 and the movable side electrode 12, and 11 e is a brazed and fixed portion with the reinforcing plate 15. The diameter φB of the hollow portion 11b is appropriately determined depending on the blocking performance and the required area of the contact portion 11d. The depth t1 of the hollow portion 11b is preferably 6 mm or less from the viewpoint of blocking performance. As the depth t1 of the depression 11b is increased, the distance between the arc and the current flowing through the spiral blade 13 is increased, so that the magnetic field strength acting on the arc is reduced, and as a result, the driving force is reduced. As a result, the speed of rotating in the circumferential direction decreases, causing a reduction in the shut-off performance.

  When a large current is interrupted, the current flowing through the spiral blade 13 where the arc is generated generates a magnetic field and the arc is driven. However, since the hollow portion 11c is provided at the center on the back side of the electrode, the spiral blade 13 is The flowing current is concentrated on the electrode facing surface side, and the magnetic field intensity acting on the arc is larger than when there is no depression 11c. The arc rotates on the contact portion 11d and local overheating is suppressed, but the large current interruption performance is influenced by the heat capacity of the contact portion. In order to secure a heat capacity necessary for current interruption and to suppress an increase in the electrode thickness, it is desirable that the diameter φC of the depression 11c be equal to or smaller than the depression on the opposite surface side φB. The depth t2 of the electrode back-side depression 11c is a value that is appropriately determined from the rated current value and the strength depending on the electrode material. If the purpose is only to improve the strength of the magnetic field acting on the arc, the dent portion diameter φC should be as large as possible and the depth t2 should be as deep as possible. To decide. Furthermore, since the electrode back surface side depression 11c is provided, the area of the brazing fixing part 11e between the fixed electrode 11 and the reinforcing plate 15 is reduced, and the leakage current between the spiral blades 13 via the reinforcing plate 15 is reduced. Decrease. This leakage current causes a reduction in the magnetic field strength acting on the arc due to a decrease in the current flowing through the spiral blade 13 where the arc exists, and a reduction in the magnetic field strength that drives the arc by the magnetic field generated by the leakage current itself. It produces good results for the driving force of the arc.

  By providing the recess 11c for controlling the current distribution flowing through the spiral blade 13 on the back surface side of the fixed side electrode 11 (movable side electrode 12), the current flows more to the electrode facing surface side and acts on the driving of the arc. Magnetic field strength increases. Further, since the reinforcing plate 15 is brazed and fixed to the back surface of the fixed side electrode 11 (movable side electrode 12), a leakage current flows between the spiral blades 13 via the reinforcing plate 15 to drive the arc. Although the magnetic field strength is reduced, the leakage current is reduced by the recess 11c, and the magnetic field strength acting on the driving of the arc is increased. Therefore, it is possible to provide a vacuum valve in which the arc drive start time is short, the rotation speed is further increased, local overheating of the electrode surface is suppressed, and the large current interruption performance is improved. In addition, when the diameter of the electrode is reduced, generally the magnetic field strength for driving the arc is reduced, so that the interruption performance is reduced, but the magnetic field intensity necessary for high current interruption can be obtained by this current distribution control means, A miniaturized vacuum valve can be provided.

Embodiment 2. FIG.
A second embodiment of the present invention will be described below with reference to FIGS. 4A is a top view of the fixed side electrode, FIG. 4B is a sectional view of the fixed side electrode, FIG. 4C is a bottom view of the fixed side electrode, and FIG. 5A is a top view of the fixed side electrode. 5B is a bottom perspective view of the fixed electrode, FIG. 6A is a top view of another modification of the fixed electrode, and FIG. 6B is another modification of the fixed electrode. FIG. 6C is a bottom view of another modification of the fixed electrode, FIG. 7A is a top perspective view of another modification of the fixed electrode, and FIG. 7B is a diagram of the fixed electrode. It is a bottom surface perspective view of another modification.

The configuration of the vacuum valve is the same as or equivalent to that of the first embodiment described above, and since the fixed side electrode and the movable side electrode are symmetrical, only the fixed side electrode will be described.
4 and FIG. 5 shows an example of a spiral electrode having four spiral blades 13 in which spiral blades 13 are formed by spiral grooves 11a. The fixed-side electrode 11 has a central recess portion 11b having a shape in which the center portion on the opposite surface side between the electrodes is circularly depressed, and the spiral groove 11a has a groove width that increases in three steps from the electrode-facing surface side to the electrode back surface. An example is shown (groove width W1 <groove width W2).
Further, as shown in FIGS. 6 and 7, the width of the groove 11a of the fixed electrode 11 may be increased uniformly (linearly or in a curve), and no matter how many steps the groove width increases. good. The shape of the groove 11a may be determined as appropriate based on ease of manufacture, current carrying capacity (cross-sectional area / resistance value of the spiral blade 13), and mechanical strength.

  When a large current is interrupted, the current flowing through the spiral blade 13 where the arc is generated generates a magnetic field and drives the arc. However, the spiral groove 11a is enlarged from the electrode facing surface side to the electrode back surface. The current flowing through the spiral blade 13 is distributed to flow more on the electrode facing surface side, and the magnetic field intensity acting on the arc becomes larger. When the arc moves from the spiral blade 13 to the adjacent spiral blade 13, the smaller the spiral groove 11a, the easier the transition and the local overheating becomes smaller. However, when the width of the spiral groove 11a is simply reduced, the leakage current through the reinforcing plate 15 is increased, resulting in a decrease in the strength of the magnetic field acting on the arc. Due to the thermal damage, the spiral groove 11a is filled and can no longer serve as a spiral electrode. There is an optimal spiral groove whose groove width does not change depending on the electrode diameter and cutoff current value, but by increasing the groove width toward the back side of the electrode, the joint area between the back side of the electrode and the reinforcing plate is reduced and the spiral blade By increasing the distance between them (the length connected by the reinforcing plate), the resistance is increased, the leakage current through the reinforcing plate 15 is also suppressed, and the magnetic field strength acting on the arc can be increased.

  In order to control the distribution of current flowing through the spiral blade 13 of the fixed side electrode 11 (movable side electrode 12), the groove width of the spiral groove 13 is increased toward the back surface of the electrode, so that the current is more on the electrode facing surface side. And the magnetic field strength acting on the arc drive increases. Further, since the reinforcing plate 15 is brazed and fixed to the back surface of the fixed side electrode 11 (movable side electrode 12), a leakage current flows between the spiral blades 13 via the reinforcing plate 15 to drive the arc. Although the magnetic field strength is reduced, the leakage current is reduced by increasing the width of the back surface side of the spiral groove 11a, and the magnetic field strength acting on the driving of the arc is increased. Therefore, it is possible to provide a vacuum valve in which the arc rotation start time is short, the rotation speed is further increased, local overheating of the electrode surface is suppressed, and the large current interruption performance is improved. In addition, when the diameter of the electrode is reduced, generally the magnetic field strength for driving the arc is reduced, so that the interruption performance is reduced, but the magnetic field intensity necessary for high current interruption can be obtained by this current distribution control means, A miniaturized vacuum valve can be provided.

Embodiment 1 and Embodiment 2 described above have the following characteristic points.
Features 1 A pair of electrodes are supported in a vacuum container so as to be able to contact and separate, and arms extending in a circumferential direction are formed on the electrodes so that a magnetic field generated by a current flowing through the electrodes drives an arc generated between the electrodes. In the vacuum valve, a current limiting structure for limiting the current flowing on the surface opposite to the surface facing the counterpart electrode of the electrode and biasing the current flowing in the arm portion of the electrode toward the facing surface is defined as the facing surface. It is provided on the opposite side.
Features 2 The feature point 1 is characterized in that a concave portion is provided at a central portion of the electrode on the facing surface side, and a pair of electrodes are contacted and separated around the concave portion.
Feature point 3. In the feature point 1 or the feature point 2, the current limiting structure is a recess provided in a central portion of a surface of the electrode opposite to the facing surface.
Feature point 4. In the feature point 3, the diameter of the recess provided in the center of the surface opposite to the facing surface of the electrode is smaller than the diameter of the recess in the center of the electrode on the facing surface side. To do.
Feature point 5. The arm extending in the circumferential direction of the electrode according to any one of claims 1 to 4, is formed by a groove provided in a spiral shape from a central portion of the electrode toward a peripheral portion of the electrode, The shape is characterized in that the groove width is large from the opposite surface side of the electrode toward the opposite surface side.
Feature point6. A pair of electrodes are supported in a vacuum container so as to be able to contact and separate, and an electrode having arms extending in a circumferential direction is formed so that a magnetic field generated by a current flowing through the electrodes drives an arc generated between the electrodes, There is a depression in the center of the opposing surface side of the electrodes, and the electrodes are in contact with each other on the outer peripheral side, and the current distribution flowing through the arm portion of the electrode on the opposite side of the opposing surface of the electrode is controlled It is characterized in that means for performing the above is provided.
Feature 7 The feature 6 is characterized in that a depression is provided in the center of the surface opposite to the opposing surfaces of the electrodes.
Feature point 8. The feature point 7 is characterized in that the diameter of the hollow portion on the side surface opposite to the facing surface between the electrodes is equal to or smaller than the diameter of the hollow portion in the central portion on the facing surface side.
Feature point 9. In the feature point 6, the arm extending in the circumferential direction of the electrode is formed by a groove provided in a spiral shape from the center portion of the electrode toward the peripheral portion, and the groove shape is formed on the opposite surface from the opposite surface side of the electrode. The groove width is increased toward the side.
Feature point 10. By providing a means for controlling the current distribution flowing through the spiral blade on the opposite side of the surface facing the spiral electrode, the magnetic field generated by the current distribution flowing through the spiral blade acts more on the arc drive than before. In addition, it is possible to obtain the magnetic field strength necessary for driving the arc with respect to the reduction in the diameter of the electrode, and it is possible to provide a vacuum valve having a reduced spiral electrode structure.
Feature point 11. Means for controlling the current distribution flowing through the spiral blades is provided on the opposite side of the opposing surface of the electrode.
Feature point 12. A recess is provided in the center of the opposite surface of the electrode facing surface, and the current distribution flowing through the spiral blade is improved so that the current flows more toward the facing surface.
Feature point 13. A recess is provided in the center of the opposite surface of the electrode facing surface, and the diameter of this recess is smaller than the diameter of the recess on the electrode facing surface, improving the current distribution flowing through the spiral blade and the heat capacity of the part where the arc is driven to rotate Is to secure.
Feature point 14. A spiral blade is formed by providing a spiral groove from the center to the periphery of the electrode, and this groove shape increases the groove width from the electrode facing surface side to the opposite surface side. The distribution is improved so that a current flows to the opposite surface side. Feature point 15. By providing means for controlling the current distribution flowing through the spiral blade on the opposite surface side of the opposed surface of the spiral electrode, the current flows more toward the electrode opposed surface side, and the magnetic field strength acting on the driving of the arc is increased. Furthermore, since the reinforcing plate is brazed and fixed to the opposite surface of the spiral electrode, a leakage current flows between the spiral blades through the reinforcing plate, reducing the magnetic field strength for driving the arc. Leakage current is reduced by the distribution control means, and the magnetic field strength acting on the driving of the arc is increased. Therefore, it is possible to provide a vacuum valve in which the arc drive start time is short, the rotation speed is further increased, local overheating of the electrode surface is suppressed, and the large current interruption performance is improved. In addition, when the diameter of the electrode is reduced, the magnetic field strength for driving the arc is generally lowered, so that the interruption performance is lowered. However, since the required magnetic field strength can be obtained by this current distribution control means, the vacuum is reduced in size. A valve can be provided.

  1 to 7, the same reference numerals denote the same or corresponding parts in each figure.

1 Insulating cylinder,
2 fixed end plate,
3 Movable end plate,
4 Fixed side electrode rod,
5 movable electrode rod,
6 Bellows,
7 Arc shield,
11 Fixed electrode,
11a spiral groove,
11b Opposite surface side depression,
11c Indentation on the back side (current limiting structure),
11d contact part,
11e brazing fixing part,
12 movable electrode,
13 Spiral feather (arm),
15 Reinforcement plate.

Claims (5)

A pair of electrodes are supported in a vacuum container so as to be able to contact and separate, and a magnetic field generated by a current flowing through the electrodes drives a circular arc generated between one electrode and the other electrode of the pair of electrodes. In a vacuum valve with arms extending in the direction formed on the electrode,
A current limiting structure that limits the current flowing to the surface opposite to the surface facing the counter electrode of the electrode and biases the current flowing through the arm portion of the electrode toward the facing surface, opposite to the facing surface A vacuum valve provided in
The vacuum valve , wherein the current limiting structure is a recess provided in a central portion of a surface opposite to the facing surface of the electrode .   2. The vacuum valve according to claim 1, wherein a recess is formed in a central portion of the electrode on the side of the facing surface, and a pair of electrodes are contacted and separated around the recess. The diameter of the hollow part provided in the center part of the surface on the opposite side to the said opposing surface of the said electrode is smaller than the diameter of the hollow part of the central part by the side of the said opposing surface of the said electrode. Or the vacuum valve of Claim 2. A pair of electrodes are supported in a vacuum container so as to be able to contact and separate, and a magnetic field generated by a current flowing through the electrodes drives a circular arc generated between one electrode and the other electrode of the pair of electrodes. In a vacuum valve with arms extending in the direction formed on the electrode,
A current limiting structure that limits the current flowing to the surface opposite to the surface facing the counter electrode of the electrode and biases the current flowing through the arm portion of the electrode toward the facing surface, opposite to the facing surface A vacuum valve provided in
The arm extending in the circumferential direction of the electrode is formed by a groove provided in a spiral shape from the center of the electrode toward the peripheral edge of the electrode,
The vacuum valve characterized in that, as the current limiting structure, the shape of the groove is a shape in which the groove width increases from the opposite surface side of the electrode toward the opposite surface side . The arm extending in the circumferential direction of the electrode is formed by a groove provided in a spiral shape from the center of the electrode toward the peripheral edge of the electrode,
As the current limiting structure, the shape of the groove, any one of claims 1 to 3, characterized in that from the side of the opposing surface of the electrode is shaped groove width toward the side having a large surface of the opposite side The vacuum valve as described in.

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