Electrode structure, electrode manufacturing method, and vacuum interrupter

Abstract

To simplify and miniaturize the manufacture of a vacuum interrupter while strengthening a magnetic field generated by an electrode coil of the vacuum interrupter.SOLUTION: The fixed electrodes are provided with electrodes coils 11a, 11b formed by laminating coil parts 111112. A twin-helical slit 15,16 is provided around the outer periphery of the coil portion 111,112. The slit 1516 has circumferential slits 15a and 16a formed along the circumferential direction on the outer peripheral surface on one end side, and inclined slits 15b and 16b formed continuously from the circumferential slits 15a and 16a. The inclined slits 15b and 16b are inclined with respect to the axis of the coil portion 111112, and the slit trailer 15c and 16c are formed up to the vicinity of the other end side. The magnetic field is strengthened by making the slit trailer 15c and the slit electrode 16c face each other and aligning the positions thereof in the circumferential direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an electrode structure for a vacuum interrupter, a method for manufacturing the electrode, and a vacuum interrupter using the electrode. [Background technology]

[0002] As is well known, a vacuum interrupter is configured by housing a pair of separable electrodes in a vacuum insulating container. Each electrode has an electrode coil that generates a magnetic field and a contact (electrode contact part) joined to the tip of the coil so as to face each other.

[0003] When the contacts of the electrodes are separated, an arc is generated between the contacts, which is diffused by the magnetic field generated by each electrode coil, preventing local heating of the contacts.

[0004] For example, according to the electrode structures of Patent Documents 1 and 2, a group of slits is provided on the outer periphery of the electrode coil to provide a magnetic field generation function. That is, as shown in Fig. 8, slits 31 and 32 are provided on both ends of the outer periphery of electrode coil 30 to form a twin helical structure coil. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2003-86067 [Patent Document 2] Patent Publication No. 2003-86068 [Patent Document 3] Patent Publication No. 2020-194733 Summary of the Invention [Problem to be solved by the invention]

[0006] The twin helical structure of Patent Documents 1 and 2 increases the strength of the magnetic field and uniformly distributes the arc that occurs during interruption, thereby improving interruption performance.

[0007] In this type of twin helical structure, it is preferable to increase the rotation angle of the slits formed on the outer periphery of the electrode coil in order to strengthen the magnetic field. However, this may be subject to structural restrictions.

[0008] For example, in the case of a twin helical structure, the slits 31 and 32 must be machined from both ends of the electrode coil 30 using a rotary blade (not shown), which is time-consuming and may reduce production efficiency. Also, to avoid interference between the rotary blade and a fixing jig during production, a certain distance L1 (L1 = 10 mm or more) must be left from both ends of the electrode coil 30, making it difficult to reduce the size.

[0009] The present invention has been made to solve such conventional problems, and aims to strengthen the magnetic field generated by the electrode coil of a vacuum interrupter while simplifying and miniaturizing the production thereof. [Means for solving the problem]

[0010] (1) One aspect of the present invention is a structure of a pair of electrodes housed in a vacuum insulating container and capable of being moved toward and away from each other, Each of the electrodes is The electrode coil includes a plurality of coil portions stacked in the axial direction, each of which has a slit formed on the outer periphery thereof, The slit is The coil portion is formed at an acute angle from one end to the other end, The slit end portions on the other end sides are opposed to each other and are aligned in the circumferential direction.

[0011] (2) Another aspect of the present invention is a method for producing the electrode, a step of holding and fixing a gripping portion of the pipe-shaped conductor with a fixing jig; forming a slit at an acute angle around the outer periphery of the conductor from one end toward the other end; a step of cutting out a coil material from the conductor according to a required length in the axial direction including the slits; preparing the plurality of cut-out coil materials, disposing one of the coil materials to be joined upside down, and joining the coil materials by aligning the slit end of one of the coil materials with the slit end of the other coil material so as to face each other; It is characterized by having:

[0012] (3) The present invention can be configured as a vacuum interrupter having the above electrode structure. [Effects of the Invention]

[0013] According to the present invention, it is possible to strengthen the magnetic field generated by the electrode coil of the vacuum interrupter, while simplifying the production thereof and reducing its size. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] Manufacturing process diagram. [Figure 5] 10 is a schematic diagram showing the angle θ between the coil portion and the processing blade at the start of the slit. FIG. [Figure 6] (a) is an analysis diagram of the comparative example, and (b) is the current distribution diagram of the same. [Figure 7] (a) is an analytical diagram of the embodiment, and (b) is a current distribution diagram of the same. [Figure 8] FIG. 1 is a side view showing a conventional twin helical structure. [Figure 9] 1A is a partially enlarged view showing the state where excess brazing material has entered the end portion of the slit in Patent Document 3, and FIG. 1B is a partially enlarged view showing the state where there is a shortage of brazing material at the connection portion between the coil portions of the same product. [Figure 10] (a) is an enlarged view of the slit in Figure 9(a) with a notch at the end, and (b) is a simplified view of the slit in (a) with a twin helical structure. DETAILED DESCRIPTION OF THE INVENTION

[0015] An electrode structure (electrode manufacturing method) according to an embodiment of the present invention will be described below. This electrode structure is mainly used in a vacuum interrupter (VI) of a vacuum circuit breaker (VCB). This vacuum circuit breaker can be used, for example, in a switchgear.

[0016] The vacuum interrupter includes a vacuum vessel having an insulating cylindrical body containing the electrode structure, one axial end of the cylindrical body sealed by a fixed flange as a fixed side, and the other axial end sealed by a movable flange as a movable side, and a cylindrical shield surrounding the outer periphery of the electrode structure is supported on the inner periphery of the cylindrical body. [Example]

[0017] Reference numeral 1 in Figure 1 indicates an embodiment of the electrode structure. Here, a lead 13a is provided on the fixed flange, while a lead 13b is inserted into a through-hole (not shown) in the movable flange so as to be movable along the axial direction. One end of a bellows (not shown), which is expandable and contractible along the axial direction, is joined to this lead 13b, and the other end of the bellows is joined to the movable flange.

[0018] Cylindrical fixed electrode 2 and movable electrode 3 are provided at the tips of leads 13a and 13b, respectively. Here, lead 13b can be moved axially as shown by arrow S to move movable electrode 3 toward and away from fixed electrode 2, thereby freely conducting or cutting off current between the two electrodes 2 and 3. Note that FIG. 1 shows a state in which movable electrode 3 is separated from fixed electrode 2, and represents an example of the state of an analytical test described below.

[0019] (1) Fixed electrode 2 and movable electrode 3 The fixed electrode 2 and the movable electrode 3 are mainly composed of electrode coils (magnetic field generating electrode coils) 11a, 11b. These electrode coils 11a, 11b are formed by stacking cylindrical coil portions 111, 112 (see FIG. 2) in the axial direction and joining them using a joining material such as silver solder.

[0020] In Figure 1, 111a and 112a indicate coil portions 111 and 112 that constitute electrode coil 11a, and 111b and 112b indicate coil portions 111 and 112 that constitute electrode coil 11b. Coil portions 111a, 112a, 111b, and 112b are formed in similar shapes with the same dimensions, and electrode coils 11a and 11b are arranged symmetrically with respect to coil portions 111 and 112.

[0021] That is, the coil portions 112a and 112b face each other, and the electrode contact portions (contactors) 14a and 14b are bonded to the facing surfaces using the bonding material. Also, the coil portions 111a and 111b have electrode adapters 12a and 12b, which are connected to the leads 13a and 13b, respectively, bonded to the end surfaces opposite the facing surfaces using the bonding material.

[0022] Furthermore, a plurality of slits 15, 16 are obliquely formed around the outer periphery of the coil portions 111a, 112a, 111b, 112b to generate a magnetic field. As shown in Fig. 3, the slits 15, 16 have circumferential slit portions 15a, 16a and inclined slit portions 15b, 16b.

[0023] As shown in Fig. 3, the circumferential slits 15a and 16a are formed along the circumferential direction on the outer peripheral surfaces of the coil portions 111a, 112a, 111b, and 112b on one end side (P side). The inclined slits 15b and 16b are formed continuously from the circumferential slits 15a and 16a and are inclined at an inclination angle α (α<90 degrees) with respect to the axis Z (see Fig. 2) of the coil portions 111a, 112a, 111b, and 112b, with the slit end portions 15c and 16c extending to the vicinity of the other end side (Q side). The circumferential slits 15a and 16a may also be formed in the electrode contact portions (contactors) 14a and 14b or the electrode adapters 12a and 12b.

[0024] The inclined slit portions 15b and 16b of the coil portions 111a and 112a are inclined in the same direction, and the inclined slit portions 15b and 16b of the coil portions 111b and 112b are inclined in the same direction, thereby providing electrode coils 11a and 11b with a twin helical structure as in Patent Documents 1 and 2.

[0025] However, in this embodiment, as shown in Fig. 1, the inclined slit portions 15b and 16b of the electrode coils 11a and 11b are oriented in opposite directions, resulting in an electrode structure with a transverse magnetic field (transverse magnetic field type), as indicated by the magnetic flux indicated by the dashed arrows. In this case, as shown in part D in Fig. 2, the slit end portions 15c and 16c of the inclined slit portions 15b and 16b are opposed to each other, and the circumferential positions are aligned, thereby strengthening the magnetic field. This point will be explained based on the following analytical test.

[0026] (2) Analysis test Electrode coils 40a and 40b of a comparative example (known technology) shown in the analysis model of FIG. 6(a) were prepared and subjected to a comparative test with electrode coils 11a and 11b of the embodiment shown in the analysis model of FIG. 7(a).

[0027] That is, for the comparative example and the example, (A) Prepare fixed electrode coils 40a and 11a and movable electrode coils 40b and 11b. (B) After supplementing the electrode contact portions 14a, 14b and electrode adapters 12a, 12b required for the electrode coils 40a, 40b, 11a, 11b, (C) A columnar path (conductor) 20, which serves as a current path simulating an arc, was connected to the electrode contacts 14a and 14b on the movable and fixed sides, and the Lorentz forces generated in the path 20 were compared.

[0028] The transverse magnetic flux density B at the electrode contact portions 14a and 14b r As long as there is no magnetic flux saturation or external magnetic flux, the Lorentz force is proportional to the current based on a coefficient determined by the shape of the current path, magnetic permeability, etc., and by comparing the Lorentz force under conditions of the same length and current, it is possible to compare changes in magnetic flux density due to differences in the shape of the electrode coil.

[0029] The magnetic field strength H and magnetic flux density B are expressed as B = μH (μ = magnetic permeability), and the difference in magnetic field strength can be expressed by comparing the Lorentz forces. This comparative test confirmed that if the Lorentz force acting on the arc (path 20) in the comparative example is 100%, the Lorentz force in the example is approximately 140%.

[0030] That is, in the example and comparative example, current I flows between slits 15 and 16, but in the example, current Ia flows between slit end portions 15c and 16c, which causes a difference from the comparative example in the region where current flows in the opposite direction (see Figures 6(b) and 7(b)), which causes changes in the transverse magnetic flux density and Lorentz force, resulting in an improvement in Lorentz force of approximately 40%. In this respect, the effect of strengthening the magnetic field by the electrode structure of the example was confirmed.

[0031] Furthermore, the Lorentz force allows the arc generated at the time of interruption in a transverse magnetic field type electrode structure to move in the circumferential direction, suppressing the concentration of heat and metal melting at the electrode contact points, dispersing the energy generated in the arc, and increasing the arc resistance by cooling via the metal at the electrode contact points 14a and 14b.

[0032] Therefore, it was confirmed that the greater the Lorentz force acting on the arc, the more likely it is that the arc will not continue and will be brought to an interrupted state, and in this respect too, the example is superior to the comparative example.

[0033] (3) Manufacturing method of electrode coils 11a and 11b A method for manufacturing the electrode coils 11a and 11b will be described with reference to Figures 4 and 5. Here, a pipe-shaped conductor 21 is prepared in advance, and the electrode coils 11a and 11b are manufactured by the following steps S01 to S04 using a chuck device 22 as a fixing jig. Note that the P side in Figure 4 is called one end side of the conductor 21, and the Q side is called the other end side.

[0034] S01: First, the other end of the conductor 21 is gripped and fixed by the chuck device 22. The portion of the conductor 21 gripped by this chuck device 22 is designated as the chuck portion 21a, and a sufficient gripping margin is ensured by leaving a distance L2 between the cut surface 24 of the conductor 21 and the chuck portion 21a.

[0035] S02: Next, while maintaining the state of S01, the rotary blade 23 of the milling machine is inserted from one end side of the conductor 21 to perform slit acute angle processing on the conductor 21 and cut grooves for the slits 15 and 16. At this time, the portions corresponding to the circumferential slit portions 15a and 16a are cut in the circumferential direction from one end side of the conductor 21, and then the portions corresponding to the inclined slit portions 15b and 16b are cut at an acute angle (inclination angle α<90°) as shown in Fig. 5.

[0036] S03: After forming the grooves for the slits in S02, the coil portions 111 and 112 are cut out from the cut-out surface 24. Here, the cut-out surface 24 is positioned from the other end of the conductor 21 according to the length of the slit and the required length in the axial direction.

[0037] S04: After cutting out in S03, the processes of S02 and S03 are executed again with the cut surface 24 as one end side of the conductor 21, and the number of coil portions 111 and 112 required to form the electrode coils 11a and 11b are cut out to form coil portions 111a, 112a, 111b, and 112b.

[0038] 1 and 2, the coil portions 112a and 112b are inverted and arranged upside down relative to the coil portions 111a and 111b, so that the slit end portions 15c and 16c of the coil portions 111a and 111b and the slit end portions 15c and 16c of the coil portions 112a and 112b are arranged on the joint side.

[0039] At this time, the slit end portions 15c, 16c of the coil portions 111a, 111b are opposed to the slit end portions 15c, 16c of the coil portions 112a, 112b, and the circumferential positions are aligned and joined to complete the electrode coils 11a, 11b.

[0040] According to this manufacturing method, since it is only necessary to stack coil portions 112a and 112b on coil portions 111a and 111b, there is no need to form slits 31 and 32 from both ends of electrode coil 30 (see FIG. 8) as in the past. This makes it possible to increase the rotation angle of slits 15 and 16, thereby strengthening the magnetic field of the twin helical structure.

[0041] Furthermore, since there is no need to form slits 31 and 32 from both ends of electrode coil 30 (see FIG. 8) as described above, electrode coils 11a and 11b can be easily produced and can also be made smaller.

[0042] (4) Comparison with Patent Document 3 Patent Document 3 proposes an electrode coil 30 in which spiral coils 30a and 30b (see FIGS. 9 and 10) are stacked. This electrode coil 30 has the following features: Spiral coils (hereinafter referred to as coil portions) 33a and 33b each having slits formed on both ends Alternatively, the coil portions 33a and 33b each have a slit on one end and no slit on the other end. However, unlike this embodiment, it is not suitable for a twin helical structure for the following reasons.

[0043] (A) If the coil portions 33a and 33b with slits formed on both ends are stacked, it will not be a twin helical coil but a spiral coil. Also, since one end is a planar cup shape, it is necessary to process from both sides (both ends) by first slitting from the top (one end) and then slitting from the bottom (the other end), which requires processing of the surfaces near the ends.

[0044] In contrast, according to this embodiment, the slits 15 and 16 can always be formed from one end side, and the twin helical structure can be produced without the need for such processing. Therefore, as described above, the electrode coils 11a and 11b can be easily produced, and the magnetic field of the twin helical structure can be strengthened.

[0045] (B) When a structure with a slit on the connection portion 41 side of the coil portions 33a and 33b is stacked with a structure without a slit on the connection portion 41 side, the difference in structure at the slit end portion 31a of the twin helical structure generated at the connection portion may cause a reverse current to occur, weakening the generated magnetic field.

[0046] That is, if no processing is performed on the slit end portion 31a, the connection portion will have the configuration shown in Fig. 9. In this case, there is a risk that excessive brazing material 41 will get in during brazing, particularly in the portion where the slit forms an acute angle (portion K), as shown in Fig. 9(a).

[0047] 9(b), there is a risk of unexpected excessive slit formation due to a shortage of brazing material 41. This may cause the position of the slit end portion 31a of the twin helical structure to become unstable, which may affect the circumferential current between the slits.

[0048] In this case, as shown in FIG. 10(a), the above-mentioned concern can be resolved by providing a notch 31b so that the slit end 31a of the slit 31 does not form an acute angle, and by preparing a sufficient amount of brazing material 41.

[0049] However, as shown in Fig. 10(b), the shape of the slit end portions 31a, 32a of the twin helical structure becomes asymmetric. Also, if one of the slit end portions 31a, 32a becomes constricted in the circumferential direction, it may cause an unexpected current that weakens the magnetic field.

[0050] In this regard, according to this embodiment, coil portion 112 is inverted relative to coil portion 111 and arranged upside down, and the other ends of coil portion 111 and coil portion 112 are joined together. In this case, slit end portions 15c and 16c of inclined slit portions 15b and 16b do not reach the connection portions of coil portions 111 and 112, and there is no risk of the problems shown in Figures 9(a) and 9(b) occurring. In fact, the magnetic field is strengthened by aligning the widthwise positions of slit end portions 15c and 16c, and a significant difference in configuration and effect is observed.

[0051] (5) Other / Other Examples The present invention is not limited to the above-described embodiment, and can be modified within the scope of the claims. For example, an electrode structure of a vertical magnetic field (vertical magnetic field type) can be adopted in which the inclined slit portions 15b, 16b of the electrode coils 11a, 11b are provided in the same direction around the circumference.

[0052] Even in the case of a longitudinal magnetic field, the stronger the generated magnetic field strength, the better. This is because the longitudinal magnetic field generated by the electrode coils 11a and 11b has the effect of preventing the arc from continuing by increasing the cross-sectional area of ​​the arc, and this effect is more pronounced as the longitudinal magnetic field becomes stronger.

[0053] 1 is turned upside down, and the coil portion 112a of the electrode coil 11a and the coil portion 111b of the electrode coil 11b are made to face each other. In this case, the electrode contact portions 14a and 14b are joined to the opposing surfaces of the coil portion 112a of the electrode coil 11a and the coil portion 111b of the electrode coil 11b, and the electrode adapters 12a and 12b are joined to the end surfaces of the coil portions 111a and 112b opposite to the opposing surfaces using the joining material.

[0054] As a result, the inclined slits 15b and 16b of the electrode coil 11a and the inclined slits 15b and 16b of the electrode coil 11b are inclined in the same direction, and are configured as electrodes for a vertical magnetic field. Note that a vacuum interrupter using the electrode coils 11a and 11b as the electrodes 2 and 3 also constitutes the present invention. [Explanation of symbols]

[0055] 1... Electrode structure 2…Fixed electrode 3... Movable electrode 11a, 11b...electrode coils 111a, 111b, 112a, 112b...Coil section 12a, 12b...electrode adapter part 13a, 13b...Lead 14a,14b...electrode contact part 15,16...Slit 15a, 16a...Circumferential slits 15b, 16b...Inclined slit section 15c, 16c...Slit end 20...Route 21...conductor 21a...Zipper part 22...Chuck device 23...Rotary blade 24…Cut surface

Claims

1. A structure of a pair of electrodes housed in a vacuum insulating container and capable of being brought into and out of contact with each other, Each of the electrodes is The electrode coil includes a plurality of coil portions stacked in the axial direction, each of which has a slit formed on the outer periphery thereof, The slit is The coil portion is formed at an acute angle from one end to the other end, An electrode structure characterized in that the slit end portions on the other end sides are opposed to each other and aligned in the circumferential direction.

2. The electrode coil is formed by arranging one of the coil portions that are stacked and joined together upside down with respect to the other.

2. The electrode structure according to claim 1, wherein the other slit end portion faces the one slit end portion and is positioned circumferentially.

3. One of the electrodes is fixed, The other electrode is the movable side, 2. The electrode structure according to claim 1, wherein the slits of the electrode coil on the fixed side and the movable side are arranged in opposite directions to form a transverse magnetic field type.

4. One of the electrodes is fixed, The other electrode is the movable side, 2. The electrode structure according to claim 1, wherein the slits of the electrode coils on the fixed side and the movable side are provided in the same direction around the circumference to form a vertical magnetic field type.

5. A vacuum interrupter comprising the electrode structure according to any one of claims 1 to 4.

6. A method for producing the electrode according to any one of claims 1 to 4, a step of holding and fixing a gripping portion of the pipe-shaped conductor with a fixing jig; forming a slit at an acute angle around the outer periphery of the conductor from one end toward the other end; a step of cutting out a coil material from the conductor according to a required length in the axial direction including the slits; preparing the plurality of cut-out coil materials, disposing one of the coil materials to be joined upside down, and joining the coil materials by aligning the slit end of one of the coil materials with the slit end of the other coil material so as to face each other; 1. A method for manufacturing an electrode, comprising:

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