Switchgear and method for manufacturing electrodes for switchgear

Abstract

To maintain favorable arc-extinguishing performance by a magnetic material provided on an electrode.SOLUTION: A switchgear (10) includes a fixed electrode (11), a movable electrode (12) that operates such that contact and separation surfaces (44a, 48a) contact and separate with respect to the fixed electrode, and magnetic bodies (41, 42) provided on the fixed electrode and the movable electrode. The switchgear (10) magnetically drives an arc (AR) generated between the fixed electrode and the movable electrode by a magnetic field generated by the magnetic body. The fixed electrode and the movable electrode include main bodies (21, 46) having receiving portions (43, 47) that receive the magnetic body, and contact and separation surface forming portions (44, 48) that cover the receiving portions and the magnetic body and form the contact and separation surfaces. A heat insulating layer (51, 52) is laminated on the outer circumferential surface of the magnetic body.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a switchgear, and more particularly to a switchgear used for power distribution equipment and a method for manufacturing electrodes for the switchgear. [Background technology]

[0002] Patent Document 1 discloses a switchgear having a second electrode that moves in and out of contact with a first electrode, which enters a closed state when the electrodes come into contact with each other and an open state when the electrodes separate. In the switchgear, an arc is generated between the electrodes as soon as the electrodes separate from the closed state. The document discloses a configuration in which a permanent magnet is installed on each electrode, and a Lorentz force is generated by the magnetic field of the permanent magnet, which magnetically drives the arc and improves arc-extinguishing performance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2022 / 230095 Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration of Patent Document 1, the permanent magnets are exposed at each electrode, which causes problems such as damage to the permanent magnets due to the arc and a reduction in the strength of the magnetic field generated by the permanent magnets due to the heat of the arc, which prevents the generated arc from being sufficiently magnetically driven, making it difficult to improve arc extinguishing performance.

[0005] The present invention has been made in consideration of the above-described circumstances, and aims to provide a switchgear and a method for manufacturing electrodes for a switchgear that can maintain good arc-extinguishing performance provided by magnetic materials provided in electrodes. [Means for solving the problem]

[0006] One aspect of the opening and closing device of the present invention comprises a fixed side electrode, a movable side electrode that operates so that contact surfaces contact and separate with respect to the fixed side electrode, and a magnetic body provided on at least one of the fixed side electrode and the movable side electrode, and magnetically drives an arc generated between the fixed side electrode and the movable side electrode by a magnetic field generated by the magnetic body, wherein at least one of the fixed side electrode and the movable side electrode comprises a main body having a receiving portion that receives the magnetic body, and a contact and separation surface forming portion that covers the receiving portion and the magnetic body to form the contact and separation surface, and an insulating layer is laminated on the outer peripheral surface of the magnetic body at least near the contact and separation surface.

[0007] Furthermore, one aspect of the present invention provides a method for manufacturing an electrode for a switching device and an electrode for a switching device, in which contact and separation surfaces contact and separate with respect to another electrode, and is characterized by carrying out a lamination process of laminating an insulating layer on at least the outer peripheral surface of a magnetic body near the contact and separation surface, an attachment process of receiving the magnetic body in a receiving portion formed in the main body of the electrode, and then attaching a contact and separation surface forming portion that forms the contact and separation surface to the main body, and a magnetization process of magnetizing the magnetic body received in the receiving portion after the attachment process. [Effects of the Invention]

[0008] According to the present invention, the magnetic body is covered with the contact surface forming portion, so that the magnetic body can be prevented from being damaged by the arc. Moreover, the heat insulating layer is laminated on the magnetic body, so that the temperature rise of the magnetic body due to the occurrence of the arc can be suppressed. This makes it possible to maintain the strength of the magnetic field generated by the magnetic body, which in turn makes it easier to magnetically drive the arc and enables the arc extinguishing performance to be exhibited well. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic partial cross-sectional view of a switchgear according to an embodiment in an open state; [Figure 2] 3 is a schematic partial cross-sectional view of a switching device according to an embodiment in a closed state; FIG. [Figure 3]FIG. 4 is an explanatory diagram showing rated current paths of a fixed electrode and a movable electrode. [Figure 4] 10 is an explanatory diagram showing a state in which an arc is generated between a fixed electrode and a movable electrode; FIG. [Figure 5] 5A to 5C are explanatory diagrams of a manufacturing method of the movable electrode. DETAILED DESCRIPTION OF THE INVENTION

[0010] An opening / closing device according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings. Note that the present invention is not limited to the following embodiment, and can be implemented by appropriate modifications within the scope of the present invention. For the sake of convenience, some components may be omitted in the following drawings. Herein, in this specification and claims, "front," "rear," and the directions indicated by arrows in each drawing are used as references.

[0011] FIG. 1 is a schematic partial cross-sectional view of a switchgear according to an embodiment in an open state. FIG. 2 is a schematic partial cross-sectional view of a switchgear according to an embodiment in a closed state. As shown in FIGS. 1 and 2, a switchgear 10 includes a fixed electrode 11 and a movable electrode 12 arranged side by side in the front-to-rear direction. In this embodiment, the fixed electrode (electrode) 11 is arranged in the front, and the movable electrode (electrode) 12 is arranged in the rear. The switchgear 10 includes a housing (not shown) that forms a sealed internal space, and the fixed electrode 11 and the movable electrode 12 are arranged in this internal space. When the switchgear 10 is a gas-insulated switchgear, the internal space is filled with an insulating gas such as sulfur hexafluoride (SF6) or dry air. However, instead of an insulating gas, the internal space may be maintained at a vacuum.

[0012] The switchgear 10 further includes a fixed-side conductive holder 13 and a movable-side conductive holder 14 that are energized through conductors (not shown) that make up the circuit. The fixed-side conductive holder 13 and the movable-side conductive holder 14 are provided in a generally cylindrical shape with their axial directions facing the front-to-rear direction. The fixed-side conductive holder 13 holds the fixed-side electrode 11 and electrically connects the fixed-side electrode 11 to the circuit. The movable-side conductive holder 14 holds the movable-side electrode 12 and electrically connects the movable-side electrode 12 to the circuit. In this embodiment, the electrodes 11, 12 and the conductive holders 13, 14 form a disconnector that opens and closes the circuit.

[0013] The movable electrode 12 is formed in the shape of a round shaft extending in the front-rear direction. The movable electrode 12 is moved in the front-rear direction by an operation mechanism (not shown). The operation mechanism transmits driving force from a driving source such as an appropriate rotation mechanism or cylinder to the movable electrode 12 via a lever or link mechanism.

[0014] The movable electrode 12 is located at the rear and separated from the fixed electrode 11 in the open circuit state shown in Fig. 1, and is located at the front and contacts the fixed electrode 11 at its tip end (front end) in the closed circuit state shown in Fig. 2. Therefore, the movable electrode 12 is provided so as to be capable of opening and closing, moving toward and away from the fixed electrode 11, and the direction of the opening and closing movement of the movable electrode 12 is parallel to the front-to-rear direction. The opening and closing movement (advancing and retreating movement) of the movable electrode 12 causes the movable electrode 12 to approach and separate from the fixed electrode 11.

[0015] The fixed side electrode 11 has a fixed side main contact 16 and a fixed side arc contact 17 that can be brought into contact with and separated from the movable side electrode 12, and the fixed side arc contact 17 is arranged to be displaceable in the forward and backward directions, which are the same as the opening and closing direction of the movable side electrode 12.

[0016] Although not shown in detail, the fixed main contact 16 is composed of an annular conductor with an opening diameter slightly smaller than the outer diameter of the movable electrode 12. The fixed main contact 16 is provided with multiple grooves formed at predetermined intervals in the circumferential direction or multiple strips arranged in the circumferential direction, so that it exhibits flexibility or elasticity in the radial direction. The fixed main contact 16 also has a ring-shaped or spiral tension spring 18 on its outer periphery, which exerts a force in the direction of reducing the opening diameter. Therefore, in the closed state shown in Figure 2, the fixed main contact 16 comes into contact with the outer periphery of the tip end of the movable electrode 12, which is in the advanced position, with an appropriate contact pressure, allowing current to pass through.

[0017] The fixed side main contact 16 is supported in contact with an annular protrusion 13a formed at the rear end of the fixed side conductive holding part 13, allowing electricity to flow between the fixed side main contact 16 and the fixed side conductive holding part 13.

[0018] The fixed side arc contact 17 comprises a round shaft-shaped fixed side arc contact body (body) 21 having an outer diameter smaller than the opening diameter of the fixed side main contact 16, and a disk-shaped base 22 connected to the rear end of the fixed side arc contact body 21 and having a larger diameter than the fixed side arc contact body 21.

[0019] The fixed-side arc contact 17 is disposed in a movable space 13b formed in a round hole shape at the axial center of the fixed-side conductive holding part 13 so as to be displaceable in the front-rear direction. An annular wall part 13c that protrudes inward is formed in the middle part of the movable space 13b in the front-rear direction. In the fixed-side arc contact 17, the fixed-side arc contact main body 21 is inserted into the annular wall part 13c, and the base part 22 abuts against the front surface of the annular wall part 13c, thereby restricting rearward displacement of the fixed-side arc contact 17.

[0020] Annular sliding portions 24, 25 are embedded in the inner periphery of the annular wall portion 13c and the outer periphery of the base portion 22. The sliding portions 24, 25 are formed of low-friction sliding members such as wear rings. The inner periphery of the sliding portion 24 provided on the annular wall portion 13c slides against the outer periphery of the fixed-side arc contact main body 21, which displaces in the front-rear direction. The inner periphery of the sliding portion 25 provided on the base portion 22 slides against the inner periphery of the fixed-side conductive holding portion 13 (the surface on which the movable space 13b is formed) when the sliding portion 25 displaces in the front-rear direction. The sliding of the sliding portions 24, 25 guides the displacement of the fixed-side arc contact 17 in the front-rear direction.

[0021] A contact band 27 is provided on the outer periphery of the base 22 of the fixed-side arc contact 17. Electricity is passed between the inner circumferential surface of the fixed-side conductive holding part 13 and the base 22 of the fixed-side arc contact 17 via the contact band 27, and this current flow is maintained regardless of the forward or backward displacement of the fixed-side arc contact 17.

[0022] A spring member 28 is housed in the movable space 13b of the fixed-side conductive holding part 13, in front of the fixed-side arc contact 17. In this embodiment, the spring member 28 is configured by a compression coil spring, and its front end is fixed by a pressing member 29 that closes the front part of the movable space 13b. The spring member 28 is disposed between the pressing member 29 and the base 22 of the fixed-side arc contact 17. In this state, the spring member 28 is compressed from its natural length and stored in energy, applying an elastic force in a direction that displaces the fixed-side arc contact 17 rearward.

[0023] 1, when the rear surface of the base 22 is pressed against the front surface of the annular wall portion 13c by the elastic force of the spring member 28, rearward displacement of the fixed-side arc contact 17 is restricted and the fixed-side arc contact 17 is positioned in the front-rear direction. In this state, the rear end surface of the fixed-side arc contact 17 is set to be located rearward of the rear surface of the fixed-side main contact 16 and forward of the front end of the cover member 31, which will be described later.

[0024] The switching device 10 further includes an electric field mitigation shield 30 attached to the rear end of the fixed side conductive holding portion 13 so as to cover the fixed side electrode 11 from behind, and a cover member 31 provided in an opening 30a of the electric field mitigation shield 30.

[0025] The electric field mitigation shield 30 is formed in a dome shape that bulges backward, and is provided at a position where it surrounds the rear ends of the fixed-side main contact 16 and the fixed-side arc contact 17, which are contact portions of the fixed-side electrode 11 with the movable-side electrode 12. An opening 30a of the electric field mitigation shield 30 is formed so as to open in the front-rear direction at the rear of the electric field mitigation shield 30, and is formed with an opening diameter larger than the outer diameter of the movable-side electrode 12. Therefore, the tip (front end) side of the movable-side electrode 12 can be inserted into and removed from the opening 30a of the electric field mitigation shield 30 in the front-rear direction.

[0026] The cover member 31 is provided along the edge of the opening 30a in the electric field mitigation shield 30, and the tip (front end) side of the movable electrode 12 can be inserted and removed in the front-rear direction inside the annular cover member 31.

[0027] The movable side electrode 12 is supported by the movable side conductive holder 14 via two sliding parts 34. The sliding parts 34 are configured similarly to the sliding parts 24 described above, and guide the displacement of the movable side electrode 12 in the front-rear direction.

[0028] The movable-side conductive holding part 14 is provided with a contact 36 that comes into contact with the movable-side electrode 12 when the movable-side conductive holding part 14 is inserted therethrough. The contact 36 is configured in the same manner as the fixed-side main contact 16 described above, and electricity can be conducted between the movable-side conductive holding part 14 and the movable-side electrode 12 via the contact 36.

[0029] An electric field mitigation shield 38 is attached to the front end side of the movable conductive holding part 14. The electric field mitigation shield 38 is provided so as to cover the contacts 36 from the front, and is formed in the same shape as the electric field mitigation shield 30 described above.

[0030] Here, the switching device 10 further includes magnetic bodies 41 and 42 provided on both the fixed electrode 11 and the movable electrode 12. The configuration around the magnetic bodies 41 and 42 on the fixed electrode 11 and the movable electrode 12 will be described below.

[0031] In the fixed side arc contact 17 of the fixed side electrode 11, the fixed side arc contact body 21 has a receiving portion 43 formed on the rear end side (tip side) that receives the magnetic body 41. The receiving portion 43 is provided in a shape that recesses the rear end of the fixed side arc contact body 21 forward. In addition to the fixed side arc contact body 21 and the base portion 22, the fixed side arc contact 17 also has a contact / separation surface forming portion 44 that is attached to the rear end surface of the fixed side arc contact body 21 and covers the receiving portion 43 and the magnetic body 41 received in the receiving portion 43.

[0032] The movable-side electrode 12 includes a movable-side electrode main body (main body) 46 having a round shaft shape, and the movable-side electrode main body 46 includes a receiving portion 47 formed on the front end side (tip side) for receiving the magnetic body 42. The receiving portion 47 is provided in a shape in which the front end of the movable-side electrode main body 46 is recessed rearward. The movable-side electrode 12 also includes a contact-separation surface forming portion 48 attached to the front end surface of the movable-side electrode main body 46 and covering the receiving portion 47 and the magnetic body 42 received in the receiving portion 47.

[0033] The magnetic body 41 provided on the fixed-side arc contact 17 is arranged so that its entire periphery is covered by the contact-separation surface forming portion 44 and the fixed-side arc contact main body 21 and is not exposed. The magnetic body 42 provided on the movable-side electrode 12 is arranged so that its entire periphery is covered by the contact-separation surface forming portion 48 and the movable-side electrode main body 46 and is not exposed.

[0034] Each of the contact surface forming portions 44, 48 is made of arc-resistant metal. The arc-resistant metal is made of, for example, an alloy of tungsten and copper or silver, and exhibits heat resistance such that it is less likely to evaporate and be worn away even at the high temperature of the arc AR (see FIG. 4). The main material of the fixed side arc contact body 21 of the fixed side arc contact 17 and the movable side electrode body 46 is made of a conductor that exhibits good conductivity, such as stainless steel, copper, or a copper alloy.

[0035] The contact-separation surface forming portion 44 of the fixed-side arc contact 17 forms the tip side (rear end side) of the fixed-side arc contact 17, and the contact-separation surface forming portion 48 of the movable-side electrode 12 forms the tip side (front end side) of the movable-side electrode 12. The contact-separation surface forming portion 44 of the fixed-side arc contact 17 and the contact-separation surface forming portion 48 of the movable-side electrode 12 are in contact with each other in the closed-circuit state shown in FIG. 2 and are spaced apart in the open-circuit state shown in FIG. 1. The surfaces of the contact-separation surface forming portions 44, 48 that come into contact with and separate from each other are formed as contact-separation surfaces 44a, 48a, and the contact-separation surfaces 44a, 48a form the tip surfaces of the fixed-side arc contact 17 and the movable-side electrode 12. Therefore, the contact-separation surfaces 44a, 48a come into contact with and separate from each other when the movable-side electrode 12 is opened or closed in the forward / backward direction.

[0036] Heat insulating layers 51, 52 are laminated over the entire outer periphery of each magnetic body 41, 42. Each heat insulating layer 51, 52 is made of a non-magnetic material. Each heat insulating layer 51, 52 exhibits a heat insulating function of suppressing the high temperature of the arc AR (see FIG. 4) from being transmitted to the magnetic body 41, 42, and is made of, for example, polytetrafluoroethylene (PTFE) or a synthetic resin such as engineering plastic.

[0037] In the closed circuit state shown in Fig. 2, the magnetic bodies 41, 42 are arranged close to each other in the front-rear direction. Here, the magnetic bodies 41, 42 are magnetized as described below to become permanent magnets. The magnetic bodies 41, 42 are arranged so that the same poles face each other, and for example, the rear part of the magnetic body 41 provided on the fixed-side electrode 11 and the front part of the magnetic body 42 provided on the movable-side electrode 12 are both N poles (see Fig. 4).

[0038] 2, the movable electrode 12 moves forward and is inserted into the fixed main contact 16. Furthermore, the contact-separation surface forming portion 48 of the movable electrode 12 comes into contact with the contact-separation surface forming portion 44 of the fixed arc contact 17, pushing the fixed arc contact 17 forward, causing the fixed arc contact 17 to assume an advanced position and compressing the spring member 28. In the closed state, the elastic force of the spring member 28 presses the contact-separation surface forming portion 44 of the fixed arc contact 17 against the contact-separation surface forming portion 48 of the movable electrode 12, and the fixed main contact 16 comes into contact with the outer peripheral surface of the front end of the movable electrode 12 with an appropriate contact pressure.

[0039] 3 is an explanatory diagram showing the rated current path of the fixed electrode and the movable electrode. As shown in FIG. 3, in a closed-circuit state where the opening and closing operation of the movable electrode 12 is stopped, a current path is formed through the movable electrode 12 and the fixed main contact 16 to the fixed conductive holder 13 (see the white arrow in FIG. 3). This current path is considered to be the rated current path. In this closed-circuit state, the magnetic body 42 provided on the movable electrode 12 is positioned closer to the fixed arc contact 17 than the contact position between the fixed main contact 16 and the movable electrode 12. In addition, an open-circuit current path is also formed, through which current flows to the fixed conductive holder 13 via the movable electrode 12, the fixed arc contact 17, and the contact band 27.

[0040] 1 from the closed state, the movable electrode 12 is moved backward from the position shown in Fig. 2. In the initial stage of this movement, the fixed arc contact 17 is also displaced forward following the movement of the movable electrode 12 due to the elastic force of the spring member 28, and the electrical connection between the movable electrode 12 and the fixed arc contact 17 is maintained. On the other hand, when the movable electrode 12 moves backward and comes out of the fixed main contact 16, the fixed main contact 16 is separated from the movable electrode 12. Therefore, in the fixed electrode 11, the rated current path via the fixed main contact 16 is interrupted, and current flows through the open current path via the fixed arc contact 17.

[0041] When the rear end of the fixed arc contact 17 (the contact-separation surface 44a of the contact-separation surface forming portion 44) is displaced rearward relative to the rear end of the fixed main contact 16, the base 22 of the fixed arc contact 17 abuts against the annular wall portion 13c, stopping the rearward displacement of the fixed arc contact 17. In this state, the movable electrode 12 continues to move rearward, and the contact-separation surface forming portion 48 of the movable electrode 12 is separated from the contact-separation surface forming portion 44 of the fixed arc contact 17 inside the electric field mitigation shield 30. During this separation, an arc AR (see FIG. 4 ) is generated between the contact-separation surface forming portions 44, 48. Therefore, at the fixed electrode 11, the arc AR is generated at the contact-separation surface forming portion 44 of the fixed arc contact 17, preventing the generation of the arc AR at the fixed main contact 16. The arc AR extends in an irregular but generally longitudinal direction.

[0042] 4 is an explanatory diagram showing a state in which an arc occurs between the fixed electrode and the movable electrode. In this embodiment, when the movable electrode 12 and the fixed arc contact 17 separate and an arc AR occurs, a magnetic field is generated between them by the magnetic bodies 41 and 42. The magnetic field lines indicating the direction of this magnetic field are indicated by arrows in FIG. 4.

[0043] The magnetic field generated by the magnetic bodies 41 and 42 extends in the front-rear direction from the surface where the N pole is formed, then immediately curves and generates a component perpendicular to the front-rear direction (a component parallel to the up-down direction in FIG. 4). As a result, a Lorentz force in a direction that drives the arc AR generated by the magnetic field of the magnetic bodies 41 and 42 can be exerted, and the arc AR can be effectively magnetically driven in the circumferential direction. As a result, the heat of the arc AR is transported to the surroundings, the conductivity of the arc AR is lost, and the time until the arc AR is extinguished can be shortened. As a result, the arc extinguishing performance can be improved, and the adhesion of the arc AR can be prevented, thereby reducing the amount of wear on the movable electrode 12 and the fixed arc contact 17.

[0044] Furthermore, since the magnetic materials 41 and 42 are provided on both the fixed electrode 11 (fixed arc contact 17) and the movable electrode 12 and are arranged so that they are of the same polarity and face each other, a strong component perpendicular to the arc AR can be generated in the magnetic field of the magnetic materials 41 and 42.

[0045] According to the above embodiment, the magnetic bodies 41, 42 are covered with the contact surface forming portions 44, 48, so that the magnetic bodies 41, 42 can be protected from direct exposure to the arc AR and can be prevented from being damaged by the arc AR. Moreover, the heat insulating layers 51, 52 are laminated on the magnetic bodies 41, 42, and the heat insulating effect of the heat insulating layers 51, 52 can suppress a temperature rise in the magnetic bodies 41, 42 due to the arc AR. This prevents the magnetic bodies 41, 42 from being thermally demagnetized, making it possible to maintain the strength of the magnetic field, making it easier to magnetically drive the arc AR and enabling good arc-extinguishing performance.

[0046] Furthermore, since the heat insulating layers 51, 52 are laminated on the entire outer peripheral surfaces of the magnetic bodies 41, 42, it is possible to better suppress thermal demagnetization of the magnetic bodies 41, 42 due to the high temperature of the arc AR. The heat insulating layers 51, 52 are protected by the contact surface forming portions 44, 48.

[0047] Furthermore, since the contact and separation surface forming portions 44, 48 are formed from arc-resistant metal, the heat resistance and durability at the location where the arc AR occurs can be improved, wear can be prevented, and the maintenance burden can be reduced.

[0048] 2, the magnetic body 42 provided on the movable electrode 12 is positioned closer to the fixed arc contact 17 than the contact position between the fixed main contact 16 and the movable electrode 12. This prevents the magnetic body 42 and the boundary between the movable electrode body 46 and the contact / separation surface forming portion 48 from overlapping with the rated current path, preventing them from acting as resistance to current flow. As a result, it is possible to avoid a temperature rise in the movable electrode 12 exceeding the standard value due to increased Joule heating caused by an increase in resistance, and thermal demagnetization of the magnetic body 42 due to this temperature rise.

[0049] Next, a method for manufacturing the movable side electrode 12 will be described with reference to Fig. 5. Figs. 5A to 5C are explanatory views of the method for manufacturing the movable side electrode. The fixed side electrode 11 (fixed side arc contact 17) and the movable side electrode 12 can be manufactured in roughly the same manner, so the method for manufacturing the movable side electrode 12 will be described below, and a description of the method for manufacturing the fixed side electrode 11 will be omitted. Note that when viewed from the movable side electrode 12, the fixed side electrode 11 is another electrode, and when viewed from the fixed side electrode 11, the movable side electrode 12 is another electrode.

[0050] 5A is an explanatory diagram of the lamination step and the attachment step, and shows the state before the magnetic body 42 is received in the receiving portion 47. As shown in FIG. 5A, the receiving portion 47 into which the magnetic body 42 fits snugly is formed at the tip (the upper end in FIG. 5A) of the movable side electrode body 46. Before the magnetic body 42 is received in the receiving portion 47, a lamination step is performed in which a heat insulating layer 52 is laminated on the outer peripheral surface of the magnetic body 42.

[0051] As shown in Fig. 5B, after the lamination step, the magnetic body 42 laminated with the heat insulating layer 52 is received in the receiving portion 47, and then the attachment step is performed in which the contact-separation surface forming portion 48 is attached to the attachment surface that will become the tip surface of the movable-side electrode main body 46. Fig. 5B is an explanatory diagram of the attachment step. By the attachment step, the receiving portion 47 and the magnetic body 42 are covered by the contact-separation surface forming portion 48 and are not exposed, and the contact-separation surface 48a that will become the tip surface of the movable-side electrode 12 is formed. In the attachment step, the attachment surface of the movable-side electrode main body 46 and the attachment surface of the contact-separation surface forming portion 48 that faces the attachment surface are heated by brazing or the like.

[0052] As shown in Fig. 5C, after the mounting step, a magnetizing step is performed in which the magnetic body 42 received in the receiving portion 47 is magnetized. Fig. 5C is an explanatory diagram of the magnetizing step. In the magnetizing step, with the movable-side electrode 12 after the mounting step inserted inside the magnetizing coil MC, current is passed through the magnetizing coil MC, and the magnetic body 42 is magnetized (magnetized) to N and S poles in accordance with the magnetic field generated in the magnetizing coil MC. Note that the magnetizing step described above is merely an example, and various modifications are possible, such as magnetizing using a magnetizing yoke, as long as the magnetic body 42 can be magnetized.

[0053] As described above, the magnetization process is performed in a state where the magnetic body 42 is received in the receiving portion 47 and then the contact / separation surface forming portion 48 is attached to the movable-side electrode body 46, so the magnetization process is not affected by high temperatures caused by brazing or the like in the attachment process. This not only makes it possible to avoid thermal demagnetization of the magnetic body 42 due to the arc AR, but also to avoid thermal demagnetization in the attachment of the contact / separation surface forming portion 48, which can contribute to improving the arc-extinguishing performance by magnetic drive.

[0054] The present invention is not limited to the above-described embodiment, and various modifications can be made to the embodiment. In the above-described embodiment, the size, shape, orientation, etc. shown in the accompanying drawings are not limited to these, and can be modified as appropriate within the scope of the effects of the present invention. In addition, the present invention can be modified as appropriate without departing from the scope of the object of the present invention.

[0055] In the above embodiment, the magnetic bodies 41, 42 are provided on both the fixed-side arc contact 17 (fixed-side electrode 11) and the movable-side electrode 12, but as long as the direction of the magnetic field can be set as described above, one of the magnetic bodies 41, 42 may be omitted. In other words, it is sufficient that the magnetic bodies 41, 42 are provided on at least one of the fixed-side arc contact 17 (fixed-side electrode 11) and the movable-side electrode 12.

[0056] Furthermore, the cover member 31 may be omitted as long as it can prevent the arc AR from commutating from the fixed-side arc contact 17 (fixed-side electrode 11) and the movable-side electrode 12 to the electric field mitigation shield 30.

[0057] Furthermore, the above-mentioned configuration has been described as being applied to the disconnector of the switchgear 10, but it is not limited to being applied to a disconnector, and can also be applied to a circuit breaker, a grounding switch, a disconnector with a grounding switch, etc. that open and close the electric circuit of a power system.

[0058] Furthermore, the laminated regions of the heat insulating layers 51, 52 are not limited to the entire outer peripheral surfaces of the magnetic bodies 41, 42, as long as they include at least the surfaces of the magnetic bodies 41, 42 closer to the contact and separation surfaces 44a, 48a, and there may be regions on part of the outer peripheral surfaces where the heat insulating layers 51, 52 are not laminated. For example, there is a configuration in which the heat insulating layers 51, 52 are laminated only on the surfaces of the magnetic bodies 41, 42 that face the contact and separation surface forming portions 44, 48. [Explanation of symbols]

[0059] 10: Switchgear 11: Fixed side electrode (electrode) 12: Movable side electrode (electrode) 16: Fixed side main contact 17: Fixed side arc contact 21: Fixed side arc contact body (body) 41:Magnetic material 42:Magnetic material 43: Receptor 44: Contact / separation surface forming part 44a: Contact / separation surface 46: Movable side electrode body (main body) 47: Receptor 48: Contact / separation surface forming part 48a: Contact / separation surface 51: Heat insulating layer 52: Heat insulating layer AR: Arc

Claims

1. A fixed electrode; a movable electrode that operates so that contact and separation surfaces contact and separate with respect to the fixed electrode; a magnetic body provided on at least one of the fixed electrode and the movable electrode, wherein an arc generated between the fixed electrode and the movable electrode is magnetically driven by a magnetic field generated by the magnetic body, At least one of the fixed electrode and the movable electrode is a main body having a receiving portion for receiving the magnetic body; a contact / separation surface forming portion that covers the receiving portion and the magnetic body and forms the contact / separation surface, A switching device characterized in that a heat insulating layer is laminated on at least the outer peripheral surface of the magnetic body near the contact surface.

2. 2. The switchgear according to claim 1, wherein the contact surface forming portion is formed of an arc-resistant metal.

3. 3. The opening and closing device according to claim 1, wherein the magnetic body is received in the receiving portion and magnetized in a state where the contact and separation surface forming portion is attached to the main body.

4. 3. The switchgear according to claim 1, wherein the heat insulating layer is made of a non-magnetic material and is laminated on the entire outer circumferential surface of the magnetic body.

5. the magnetic body is provided on the movable electrode, The fixed electrode has a fixed main contact that can be brought into contact with and separated from the movable electrode. a fixed arc contact that is provided so as to be displaceable in the direction of movement of the movable electrode and that generates the arc when the fixed arc contact moves away from the movable electrode, 3. The switching device according to claim 1, wherein in a closed-circuit state in which the opening and closing operation of the movable electrode is stopped, the magnetic body provided on the movable electrode is arranged closer to the fixed arc contact than to a contact position between the fixed main contact and the movable electrode.

6. 3. The switchgear according to claim 1, wherein the magnetic body is provided on both the fixed electrode and the movable electrode.

7. A method for manufacturing an electrode for a switching device in which contact and separation surfaces contact and separate with respect to another electrode, a lamination step of laminating a heat insulating layer on at least the outer peripheral surface of the magnetic body near the contact surface; a mounting step of receiving the magnetic body in a receiving portion formed on a main body of the electrode, and then mounting a contact-separation surface forming portion that forms the contact-separation surface on the main body; a magnetizing step of magnetizing the magnetic body received in the receiving portion after the mounting step;

8. 8. The method for manufacturing an electrode for a switchgear according to claim 7, wherein the mounting surface of the main body and the mounting surface forming portion are heated in the mounting step.

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