JP2012243444A - Vacuum interrupter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum interrupter whose shielding performance has been enhanced by improving the magnetic flux density distribution and the magnetic field intensity of a longitudinal magnetic field electrode.SOLUTION: In a vacuum interrupter, a current conductive shaft is provided on the back face of each of a pair of opposing electrodes, and a magnetic body is provided around each of the current conductive shaft. The U-shape magnetic body disposed at a predetermined distance from the back face of one electrode in the axis direction of the current conductive shaft with its columnar parts extended from both ends of the U-shape in the axis direction of the current conductive shaft contacting the electrode, and another magnetic body contacting the back face of the other electrode and is in an arch shape with both ends thereof located on extension lines of the columnar parts of the U-shape magnetic body in the axis direction, as a pair, form a first magnetic path. Additionally, a pair of magnetic bodies having the same shapes as the pair of the U-shape magnetic body and the arc-shaped magnetic body are respectively disposed on the back face of the respective opposing electrodes as shifted approximately 180 degrees to form a second magnetic path. Thus, the above problem is addressed.

Description

  The present invention relates to a vacuum interrupter provided with a magnetic material as means for generating a longitudinal magnetic field.

  Conventionally, in order to improve the interruption performance, a vacuum interrupter incorporating a so-called longitudinal magnetic field electrode that generates a magnetic field parallel to an arc generated between contacts has been employed.

  The longitudinal magnetic field electrode generally uses a magnetic field generated by a current flowing in a coil electrode or a slit electrode provided on the back surface of a contactor serving as a contact. On the other hand, a configuration is also known in which a longitudinal magnetic field is generated by guiding a magnetic field generated by a current flowing through a current-carrying shaft connected to the back surface of a plate electrode serving as a contact between magnetic contacts provided around the current-carrying shaft. ing.

  As a configuration in which such a magnetic body is provided, a vacuum interrupter of a type in which horseshoe-shaped (U-shaped) magnetic bodies 52 and 53 are provided on the back surfaces of the opposing electrodes 50 and 51 as shown in FIG. It has been. The two magnetic bodies 52 and 53 are formed so as to cover the circumference of the energizing shaft by more than about 180 degrees, for example, about 200 degrees, and are arranged at positions shifted from each other by about 180 degrees. Since the two magnetic bodies 52 and 53 together form a shape covering 360 degrees or more around the energizing shaft, the ends of the magnetic bodies 52 and 53 are arranged so as to partially wrap. For this reason, the magnetic resistance of the magnetic material wrap portion is lowered, and the lines of magnetic force are easily passed. (For example, refer to Patent Document 1.)

  FIG. 5 is a view showing a magnetic path formed by magnetic lines of force passing through the magnetic body by taking out only the magnetic body of the vacuum interrupter of FIG. As shown in FIG. 5, a magnetic force line Φ54 (hereinafter referred to as “loop”) passing through the magnetic bodies 52 and 53 passes between the electrodes (hereinafter referred to as “gap”) twice. Here, the lines of magnetic force that pass through the wrap locations of the magnetic bodies 52 and 53 are indicated by one loop Φ54, but actually, a vertical magnetic flux is generated around the loop Φ54. According to such a configuration, as schematically shown in FIG. 6, a bipolar range (dotted line portion) having a certain magnetic flux density or more is formed in the gap. That is, there are two substantially circular ranges around the magnetic path Φ54a and Φ54b of the loop Φ54 having a low magnetic resistance and a high magnetic flux density because it is a wrap portion of a magnetic material, and around the magnetic path Φ54a and Φ54b. It is formed. Here, the magnetic flux density above a certain level refers to a magnetic flux density that contributes to the interruption performance.

  Further, as shown in FIG. 7, a quadrupole type vacuum interrupter is also known, in which two arc-shaped magnetic bodies 57, 58 and 59, 60 are provided on the back surfaces of the electrodes 55, 56 arranged opposite to each other. ing. The magnetic bodies 57 and 58 provided on the back surface of the electrode 55 are formed so as to cover the periphery of the current-carrying shaft by more than about 90 degrees, for example, about 110 degrees, and are shifted from each other by about 180 degrees. Further, magnetic bodies 59 and 60 are disposed on the back surface of the electrode 56 at positions that are the same shape as the magnetic bodies 57 and 58 and that are shifted from these magnetic bodies by about 90 degrees. That is, by arranging the end portions of the magnetic bodies 57, 59, and 60 so as to be partially wrapped, and also wrapping the end portions of the magnetic bodies 58, 59, and 60, the magnetic resistance at each lap location is lowered and the lines of magnetic force are reduced. Is easier to pass. (For example, refer to Patent Document 2.)

  In this structure, as shown in FIG. 8, the loop Φ61 passing through the four magnetic bodies passes through the gap four times. Specifically, the loop Φ61 passes through the magnetic bodies 57, 59, 58, and 60 in this order. Here, the magnetic lines of force are shown by one loop Φ61 passing through the wrapping portions of the respective magnetic bodies, but in reality, a vertical magnetic flux is generated around the loop Φ61. According to such a configuration, as schematically shown in FIG. 9, a quadrupole range (dotted line portion) having a certain magnetic flux density or more is formed in the gap. That is, a substantially circular range in which the magnetic flux density is more than a fixed value around the magnetic path Φ61a, Φ61b, Φ61c, and Φ61d of the loop Φ61 where the magnetic resistance is low and the magnetic flux density is high because of the wrap portion of the magnetic body. Are formed in four places.

JP 60-258816 EP111638A2

  In order to increase the effect of the longitudinal magnetic field and improve the interruption performance, it is required that the magnetic flux density distribution is uniform throughout the electrode radial direction and that the magnetic field strength is strong. However, since the horseshoe-shaped vacuum interrupter described above passes through the gap at two locations per loop, it is possible to suppress a decrease in the magnetic resistance, but on the electrode, a substantially circular range in which the magnetic flux density is a certain level or more. Only two are formed. For this reason, there has been a problem that a uniform magnetic flux density distribution cannot be obtained in the radial direction of the electrode.

  Also, in the quadrupole type vacuum interrupter, by passing through the gap four times per loop, four substantially circular areas having a certain magnetic flux density distribution or more are formed on the electrode, and the horseshoe type is formed. In comparison, the distribution of magnetic flux density over the entire electrode is improved. However, the magnetic paths Φ61a, Φ61b, Φ61c, and Φ61d that are adjacent on the electrode have different magnetic flux lines, so that there are substantially circular ranges around the magnetic paths that are independent and have a magnetic flux density of a certain level or more. Four will be formed. That is, between the four substantially circular ranges having a certain magnetic flux density or more, the substantially circular ranges do not overlap, and a space with a low magnetic flux density is formed. For this reason, the problem still remains about the uniformity of magnetic flux density distribution in the whole electrode.

  Further, since the gap is passed four times per loop, the magnetic resistance of the magnetic path is increased. For this reason, the magnetic flux density in the axial direction of the longitudinal magnetic field electrode is lowered, and there is a problem that a strong magnetic field cannot be obtained.

  In order to solve the above-described problems, an object of the present invention is to provide a vacuum interrupter with improved interruption performance by improving the magnetic flux density distribution and magnetic field strength of a longitudinal magnetic field electrode.

  In order to achieve the above object, a vacuum interrupter according to the present invention has a current-carrying shaft on the back surface of a pair of electrodes facing each other, and a vacuum interrupter in which a magnetic material is provided around each current-carrying shaft. A magnetic body disposed at a predetermined distance in the axial direction of the current-carrying shaft and having a U-shape and a columnar portion extending in the axial direction of the current-carrying shaft from both ends of the U-shape, A first magnetic path is formed with a pair of magnetic bodies that are in contact with the back surface of the other electrode and are arc-shaped and whose both ends are positioned on the extension line in the axial direction of the columnar portion of the U-shaped magnetic body. In addition, another set of magnetic bodies having the same shape as the U-shaped and arc-shaped sets of magnetic bodies are arranged on the back surfaces of the opposing electrodes with a shift of about 180 degrees, and the second magnetic path is arranged. It is formed.

  A magnetic path is formed by a pair of magnetic bodies of a U shape disposed on one back surface of a pair of electrodes facing each other and an arc shape disposed on the other back surface, and has the same shape as the pair of magnetic bodies. Since the other pair of magnetic bodies are arranged with a shift of about 180 degrees on the back surfaces of the electrodes facing each other, a loop is formed at a total of two locations, thereby improving the magnetic flux density distribution in the electrode radial direction. Furthermore, since the number of times the gap passes can be suppressed to twice per loop, a strong magnetic field strength can be obtained, and the blocking performance can be improved.

It is a perspective view of the longitudinal magnetic field electrode which concerns on this invention. It is explanatory drawing of the magnetic path formed with the magnetic body of FIG. It is the top view which showed typically the magnetic field of the electrode of FIG. It is a perspective view of the conventional horseshoe type vertical magnetic field electrode. It is explanatory drawing of the magnetic path formed with the magnetic body of FIG. It is the top view which showed typically the magnetic field of the electrode of FIG. It is the perspective view which showed the conventional quadrupole type vertical magnetic field electrode. It is explanatory drawing of the magnetic path formed with the magnetic body of FIG. It is the top view which showed typically the magnetic field between the electrodes of FIG. It is a comparison figure of the axial direction magnetic flux density of this invention and the conventional longitudinal magnetic field electrode. It is the whole figure which showed the screwing fixing method of the magnetic body of this invention. It is the figure which showed the structure of the electricity supply shaft at the time of screwing fixation of the magnetic body of this invention. It is process drawing which showed the fixing method by brazing of the magnetic body of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, a disk-shaped electrode 2A is brazed to the lower end of a fixed energizing shaft 1A penetrating a fixed end plate of a vacuum valve (not shown). The electrode 2A is formed of a member excellent in interruption performance and energization performance, for example, a copper-chromium material.

  As shown in FIGS. 1 and 2, the arc-shaped magnetic body 3A is disposed so as to contact the back surface of the electrode 2A. Further, columnar portions 4a are formed in U-shapes so as to cover the energizing shaft 1A in the circumferential direction and at both end portions (opening portions) at a position keeping a predetermined distance from the arc-shaped magnetic body 3A in the axial direction of the energizing shaft 1A. A U-shaped magnetic body 4A having the same is disposed. Here, as the predetermined distance, it is desirable to have a distance equal to or greater than the gap so that two magnetic paths Φ5 and Φ6 described later do not interfere with each other.

  The columnar portion 4a extends in the axial direction of the energizing shaft 1A and toward the electrode 2A (downward in the figure), and its lower end is in contact with the electrode 2A. The arc-shaped magnetic body 3A and the U-shaped magnetic body 4A are formed so as to cover the circumference of the energizing shaft 1A by about 90 degrees (for example, about 110 degrees) and 270 degrees (for example, about 290 degrees), respectively. Yes.

  Similarly, in FIG. 1, an electrode 2B having the same shape as that of the movable side is also brazed to the upper end of the movable side energizing shaft 1B penetrating through the movable side end plate of a vacuum valve (not shown). As shown in FIGS. 1 and 2, an arc-shaped magnetic body 3B having the same shape as the movable-side arc-shaped magnetic body 3A is disposed on the back surface of the electrode 2B so as to contact the electrode 2B. The arc-shaped magnetic body 3B is arranged so that both ends thereof are located on the extension line in the axial direction of the columnar portion 4a of the movable U-shaped magnetic body 4A.

  Further, a U-shaped magnetic body 4B having the same shape as the U-shaped magnetic body 4A is disposed at a position that maintains a predetermined distance from the arc-shaped magnetic body 3B in the axial direction of the energizing shaft 1B. The columnar portion 4b of the U-shaped magnetic body 4B extends in the axial direction of the current-carrying shaft 1B and toward the electrode 2B (upward in the drawing), and its upper end is in contact with the electrode 2B. Furthermore, it arrange | positions so that the both ends of 3 A of arc-shaped magnetic bodies on the movable side may be located on the extension line | wire of the axial direction of the columnar part 4b.

  As described above, the arc-shaped magnetic bodies 3A, 3B and U-shaped magnetic bodies 4A, 4B having the same shape are respectively shifted by about 180 degrees on the back surfaces of the movable electrode 2A and the fixed electrode 2B facing each other. Has been placed. Further, since the arc-shaped magnetic body 3 and the U-shaped magnetic body 4 are formed so as to cover the circumference of the current-carrying shaft 1 by more than 90 degrees and the U-shaped magnetic body 4 by more than 270 degrees, the two magnetic bodies 3 and 4 are energized together. The periphery of the shaft 1 is covered by 360 degrees or more. For this reason, for example, the arc-shaped magnetic body 3 </ b> B and the U-shaped magnetic body 4 </ b> A are arranged so that both ends thereof wrap around each other. Therefore, the magnetic resistance is lowered at the wrapping location of the magnetic material, and the magnetic lines of force are easily passed, so that a predetermined loop is easily formed.

  Each of these magnetic bodies is fixed to the electrode and the current-carrying shaft by brazing or screwing. Since the fixing method of the magnetic body is the same on the fixed side and the movable side, only the fixing method of the magnetic body provided on the back surface of one electrode will be described here.

  In the case of screwing, as shown in FIGS. 11 and 12, through holes 7 formed in a plurality of locations in the arc-shaped magnetic body 3B and the U-shaped magnetic body 4B, and screw holes 8 formed in the energizing shaft 1A so as to correspond thereto. The screw 9 is screwed into the screw. In the present embodiment, the arc-shaped magnetic body 3B is provided with two through holes 7a and 7b, the energizing shaft 1B is formed with screw holes 8a and 8b corresponding thereto, and the screws 9 are screwed together so as to be screwed. Stopping.

  On the other hand, the U-shaped magnetic body 4B is provided with three through-holes 7c, 7d, and 7e, and the current-carrying shaft 1B is formed with 8c, 8d, and 8e corresponding thereto, and screws 9 are screwed together to be screwed. Do. Thereby, the arc-shaped magnetic body 3B and the U-shaped magnetic body 4B are integrated and fixed with the energizing shaft 1B.

  In the case of brazing and fixing, a brazing material 10 is provided on the contact surface between the arc-shaped magnetic body 3A and the electrode 2A as shown in FIG. Furthermore, the arc-shaped magnetic body 3A is brazed and fixed to the electrode 2A and the energizing shaft 1A by sandwiching the brazing material 11 in the circumferential contact portion between the arc-shaped magnetic body 3A and the energizing shaft 1A.

  On the other hand, the brazing material 12 is provided on the contact surface between the U-shaped magnetic body 4A and the electrode 2A, that is, the contact surface between the tip of the columnar portion 4a and the electrode 2A. Further, the brazing material 13 is sandwiched between the U-shaped portion of the U-shaped magnetic body 4A and the contact portion in the circumferential direction with the energizing shaft 1A, thereby fixing the electrode 2A and the energizing shaft 1A by brazing.

  Next, the magnetic path and the magnetic flux density distribution in the electrode radial direction by the above-described magnetic material arrangement will be described. In FIG. 2, a magnetic path formed by passing a magnetic line of force through each magnetic body when energized is indicated by a dotted line. As indicated by the arrows in the figure, the magnetic field lines passing through the arc-shaped magnetic body 3A pass through the gap, then reach the U-shaped magnetic body 4B, and further return to the arc-shaped magnetic body 3A, thereby forming a loop Φ5. .

  Further, the magnetic field lines passing through the U-shaped magnetic body 4A pass through the gap, reach the arc-shaped magnetic body 3B, and further return to the U-shaped magnetic body 4A to form a loop Φ6. Here, the magnetic paths are indicated by one loop Φ5 and Φ6, respectively, but actually, a vertical magnetic flux is generated around the loops Φ5 and Φ6.

  According to such a configuration, as schematically shown in FIG. 3, a range (dotted line portion) where the magnetic flux density is a certain level or more is formed in the gap. That is, the magnetic flux density is more than a certain value around the magnetic paths Φ5a, Φ6a and Φ5b, Φ6b of the loops Φ5, Φ6, which have a low magnetic resistance and a high magnetic flux density because they are the wrap portions of the magnetic bodies 3, 4. Are formed in two places. Further, in this configuration, the magnetic flux lines in the adjacent magnetic paths Φ5a, Φ6a and Φ5b, Φ6b have the same traveling direction, so that the range of the magnetic flux density is not independently formed as in the quadrupole type, Spread to fit each other. For this reason, the range in which the magnetic flux density distributed around the two loops Φ5 and Φ6 is a certain value or more is an oval shape, and the magnetic flux density distribution is spread evenly symmetrically on the electrode.

  Next, the magnetic field strength in the longitudinal magnetic field electrode of the present invention will be described in comparison with a conventional quadrupole type electrode.

  The magnetic field strength is obtained by magnetomotive force / magnetic resistance. The magnetomotive force is a force obtained by the magnetic flux generated around the current-carrying shaft and is guided between the gaps by the magnetic material. In the quadrupole type of FIG. 8, the magnetomotive force is guided to one loop Φ61. On the other hand, in the present invention shown in FIG. 2, magnetomotive forces generated with the same force around the respective energizing shafts 1A and 1B are guided to the two loops Φ6 and Φ5, respectively.

  The magnetoresistance of the entire magnetic path is proportional to g + 2d, where g is the gap distance and d is the contact thickness. Note that a non-magnetic material is used for the contact, and the magnetic resistance of this portion can be ignored.

  Since the quadrupole type passes through the gap four times per loop, the magnetic resistance is proportional to 4 (g + 2d). On the other hand, in the case of the present invention, the entire electrode passes through the gap four times per two loops. That is, the number of passes through the gap per loop is two, and the magnetoresistance is proportional to 2 (g + 2d). In the case of the present invention, when the conditions of magnetomotive force generated in each energizing shaft are the same, the magnetic resistance is ½ of the quadrupole type, so that a stronger magnetic field strength can be obtained.

  FIG. 10 is a diagram comparing axial magnetic flux density distributions on the electrodes of the vacuum interrupter of the present invention and the conventional one when the gap length is 30 mm. The vertical axis represents the magnetic flux density in the axial direction, and the horizontal axis represents the distance in the radial direction of the electrode. Curves C to E respectively show the magnetic flux densities of the quadrupole type shown in FIG. 9, the horseshoe type shown in FIG. 6, and the portion of the vacuum interrupter electrode shown in FIG. 3 cut out in the radial direction.

  Looking at the range of the electrode part (30 to 70 mm), the maximum value of the magnetic flux density of the quadrupole type C is about 0.004T, whereas the maximum magnetic flux density of the horseshoe type D and the example E is 0. It is about .012 to 0.013 T, and it can be seen that the magnetic flux density is high. That is, a stronger magnetic field strength is obtained between the gaps.

  As described above, according to the present invention, the magnetic field distribution in the electrode radial direction is improved as compared with the conventional horseshoe type by providing two magnetic paths with two gaps per loop. Compared to the quadrupole type, the magnetic field distribution in the electrode radial direction is improved, and further, the magnetic field strength of the gap can be increased, so that both the magnetic flux density distribution and the magnetic field strength can be improved. As a result, the interruption performance of the longitudinal magnetic field electrode can be improved.

1A, 1B Conducting shaft 2A, 2B Contact 3A, 3B Arc-shaped magnetic body 4A, 4B U-shaped magnetic body Φ5, Φ6 Closed magnetic field lines (loop)
g Between electrodes (gap)
d Contact thickness

Claims (1)

  In a vacuum interrupter having a current-carrying shaft on each of the back surfaces of a pair of electrodes facing each other and providing a magnetic body around each current-carrying shaft, the electrode is arranged with a predetermined distance from the back surface of one electrode in the axial direction of the current-carrying shaft. A columnar portion that is U-shaped and that extends from both ends of the U-shape in the axial direction of the current-carrying shaft, has an arc shape that abuts against the electrode, and a back surface of the other electrode; A first magnetic path is formed with a pair of magnetic bodies whose both end portions are located on the axial extension line of the columnar portion of the U-shaped magnetic body, and further, the U-shaped and arc-shaped sets are defined as one set. A vacuum interrupter, wherein a second magnetic path is formed by arranging another set of magnetic bodies having the same shape as the magnetic body, shifted by about 180 degrees on the back surfaces of the opposing electrodes.

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