Electromagnetic relays

Abstract

To provide an electromagnetic relay capable of quickly extinguishing an arc when the arc occurs.SOLUTION: A circuit breaker (100) includes a fixed terminal (1), a movable contactor (3), a moving mechanism, an igniter (51), and a housing chamber (70). The fixed terminal (1) has a fixed contact (11). The movable contactor (3) has a movable contact (31) connected to the fixed contact (11). The moving mechanism moves the movable contactor (3) from a closed position where the movable contact (31) is connected to the fixed contact (11) to an open position where the movable contact (31) is separated from the fixed contact (11). The igniter (51) generates gas by combustion. The housing chamber (70) houses the fixed contact (11) and the movable contactor (3). In the circuit breaker (100), gas is introduced into the housing chamber (70).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This disclosure relates to an electromagnetic relay.

Background Art

[0002] Patent Document 1 discloses a circuit breaker provided with a pyrotechnic actuator, which is intended to be mounted on an automobile, particularly an electric vehicle.

[0003] The circuit breaker of Patent Document 1 includes a conductor, a housing, a matrix, a punch, and a pyrotechnic actuator.

[0004] The housing is partially traversed by the conductor, and the ends of the conductor form two connection terminals for the circuit breaker. The matrix and the punch are arranged on both sides (upper side and lower side) of the conductor.

[0005] The pyrotechnic actuator moves the punch from the first position to the second position when ignited. The punch and the matrix break (split) the conductor when the punch moves from the first position to the second position. The punch has a groove. In the state where the punch is in the second position, the groove of the punch is engaged in the matrix, whereby the space in the housing is divided to form two cutting chambers.

[0006] When the punch advances from the first position to the second position and cuts the conductor, an electric arc is formed. This electric arc travels through a passage between the cutting chamber and the bottom of the groove of the punch. Near the passage, there is provided a material drawn by ablation by the electric arc to increase the voltage of the electric arc.

[0007] In an electromagnetic relay such as a circuit breaker, it is desired to quickly extinguish the arc.

Prior Art Documents

Patent Documents

[0008] [Patent Document 1] Special Publication No. 2017-507469 [Overview of the project]

[0009] This disclosure has been made in view of the above-mentioned reasons, and its purpose is to provide an electromagnetic relay capable of rapidly extinguishing an arc when one occurs.

[0010] An electromagnetic relay according to one aspect of the present disclosure comprises a first fixed terminal, a second fixed terminal, a movable contact, a pyroactuator, a housing, a coil, a movable element, and a shaft. The first fixed terminal includes a first fixed contact. The second fixed terminal includes a second fixed contact located to the right of the first fixed contact. The movable contact includes a first end provided with a first movable contact located below the first fixed contact, a second end provided with a second movable contact located below the second fixed contact, and an intermediate portion connecting the first end and the second end. The pyroactuator includes a piston provided above the intermediate portion and an igniter containing gunpowder, which causes the piston to move toward the movable contact by the combustion of the gunpowder. The housing accommodates the first fixed contact, the second fixed contact, and the movable contact. The coil is disposed outside the housing. The movable element moves upward or downward when the coil is energized. The shaft is positioned below the intermediate portion and moves upward when the movable element moves upward and downward when the movable element moves downward. The movable contact moves between a closed position in which the first fixed contact and the first movable contact are in contact and the second fixed contact and the second movable contact are in contact, and a first open position in which the first movable contact is away from the first fixed contact and the second movable contact is away from the second fixed contact, as the shaft moves upward or downward. When the gunpowder in the igniter burns, the movable contact is moved by the piston moving toward the movable contact to a second open position which is located below the first open position. The pressure in the housing when the gunpowder in the igniter is burning and the first movable contact is separated from the first fixed contact and the second movable contact is separated from the second fixed contact is greater than the pressure in the housing when the movable contact is in the closed position and the gunpowder in the igniter is not burning. [Effects of the Invention]

[0011] According to this disclosure, it is possible to quickly extinguish an arc if one occurs. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a cross-sectional view of an electrical circuit breaker according to Embodiment 1 of this disclosure. [Figure 2] Figure 2 is a perspective view of the main part of the circuit breaker shown above. [Figure 3] Figure 3 is a cross-sectional view of the same circuit breaker shown above, taken in a direction perpendicular to Figure 1. [Figure 4] Figure 4 is a cross-sectional view of the pyroactuator included in the circuit breaker shown above. [Figure 5] Figure 5 is a circuit diagram illustrating a power supply system equipped with the same circuit breaker. [Figure 6] Figure 6 is a cross-sectional view of the circuit breaker shown above during operation. [Figure 7] Figure 7 is a cross-sectional view of the circuit breaker after it has been operated. [Figure 8] Figures 8A to 8C illustrate how the arc is extended by gas in the same circuit breaker. [Figure 9] Figure 9 is a cross-sectional view of a modified example of the circuit breaker in Embodiment 1. [Figure 10] Figure 10 is a cross-sectional view of the circuit breaker shown above after it has been operated. [Figure 11] Figure 11 is a cross-sectional view of the circuit breaker according to Embodiment 2. [Figure 12] Figure 12 is a cross-sectional view of the circuit breaker shown above after it has been operated. [Figure 13] Figure 13 is a side view of a circuit breaker according to a modified example 1 of Embodiment 2. [Figure 14] Figure 14 is a side view of the same circuit breaker as shown in Figure 13, viewed from a direction perpendicular to the direction in Figure 13. [Figure 15]FIG. 15 is a side view of the above circuit breaker after operation. [Figure 16] FIG. 16 is a cross-sectional view of the circuit breaker according to Modification 2 of Embodiment 2. [Figure 17] FIG. 17 is a perspective view of the movable contact of the above circuit breaker. [Figure 18] FIG. 18 is a cross-sectional view of the circuit breaker according to Modification 3 of Embodiment 2. [Figure 19] FIG. 19 is a cross-sectional view of the circuit breaker of Specific Example 1. [Figure 20] FIG. 20 is a cross-sectional view of the above circuit breaker in the off state. [Figure 21] FIG. 21 is a cross-sectional view of the above circuit breaker after operation. ... [Figure 22] FIG. 22 is a cross-sectional view of the circuit breaker of Specific Example 2. [Figure 23] FIG. 23 is a cross-sectional view of the above circuit breaker in the off state. [Figure 24] FIG. 24 is a cross-sectional view of the circuit breaker of Specific Example 3. [Figure 25] FIG. 25 is a cross-sectional view of the above circuit breaker after operation. [Figure 26] FIG. 26 is a cross-sectional view of the circuit breaker of Specific Example 4. [Figure 27] FIG. 27 is a cross-sectional view of the above circuit breaker in the off state. [Figure 28] FIG. 28 is a cross-sectional view of the above circuit breaker after operation. [Figure 29] FIG. 29 is a cross-sectional view of the circuit breaker of Specific Example 5. [Figure 30] FIG. 30 is a cross-sectional view of the above circuit breaker in the off state. ... [Figure 31] FIG. 31 is a cross-sectional view of the above circuit breaker after operation.

BEST MODE FOR CARRYING OUT THE INVENTION

[0013] The embodiments and modifications described below are merely examples of the present disclosure. This disclosure is not limited to these embodiments and modifications, and various modifications are possible depending on the design, etc., as long as they do not depart from the technical idea related to this disclosure. Furthermore, the figures described in the embodiments and modifications below are schematic diagrams, and the ratios of the size and thickness of each component in the figures do not necessarily reflect the actual dimensional ratios.

[0014] (1) Embodiment 1 The circuit breaker (current interruption device) 100 of Embodiment 1 will be described with reference to Figures 1 to 7.

[0015] (1.1 Overview) As shown in Figure 1, the circuit breaker 100 of Embodiment 1 comprises a first fixed terminal (fixed terminal) 1, a second fixed terminal 2, a movable contact (movable terminal) 3, a holding part 4, a pyro actuator 5, and a housing chamber 70.

[0016] The first fixed terminal 1 has a first fixed contact (fixed contact) 11. The first fixed terminal 1 has a first electrode 12 that is connected to the first end of an electrical circuit.

[0017] The second fixed terminal 2 has a second fixed contact 21. The second fixed terminal 2 has a second electrode 22 that is connected to the second end of the electrical circuit.

[0018] The movable contact 3 has a first movable contact (movable contact) 31. The first movable contact 31 is connected to the first fixed contact 11. The movable contact 3 also has a second movable contact 32. The second movable contact 32 is connected to the second fixed contact 21. In this embodiment, the movable contact 3 is formed separately from the first fixed terminal 1 and the second fixed terminal 2.

[0019] The first fixed contact 11, the second fixed contact 21, and the movable contact 3 (first movable contact 31 and second movable contact 32) are housed in the housing chamber 70.

[0020] The holding part 4 holds the movable contact 3 such that the first movable contact 31 is connected to the first fixed contact 11 and the second movable contact 32 is connected to the second fixed contact 21. In particular, when no current is flowing through the movable contact 3 (when de-energized), the holding part 4 holds the movable contact 3 such that the first movable contact 31 is connected to the first fixed contact 11 and the second movable contact 32 is connected to the second fixed contact 21.

[0021] In the following, the position of the movable contact 3 where the first movable contact 31 is connected to the first fixed contact 11 is referred to as the closed position. In the closed position, the second movable contact 32 and the second fixed contact 21 are also connected.

[0022] As shown in Figure 1, the pyroactuator 5 comprises an igniter 51, a case 52, and a piston 53.

[0023] The igniter (squib) 51 is housed in a case 52. The igniter 51 generates gas through combustion. The igniter 51 contains a heating element and gunpowder (fuel). When an electrical signal flows to the heating element and the heating element heats up, the gunpowder ignites. When the igniter 51 is ignited, the gunpowder burns and generates gas. The gas generated by the igniter 51 has electrical insulating properties. Examples of gases generated by the igniter 51 include carbon monoxide, carbon dioxide, and nitrogen. The gas generated by the igniter 51 is introduced into a pressurized chamber 520 inside the case 52, increasing the pressure inside the pressurized chamber 520. In other words, the pressurized chamber 520 is subjected to the pressure of the gas generated by the igniter 51.

[0024] The piston 53 is moved by the pressure in the pressurizing chamber 520 at its first end 531, and at its second end 532, it applies a force to the movable contact 3 (directly or indirectly) that moves it away from the fixed terminal (first fixed terminal) 1, causing the movable contact 3 to move. More specifically, the piston 53 is moved by the pressure in the pressurizing chamber 520 at its first end 531, and pushed by the increased pressure in the pressurizing chamber 520, pushing the movable contact 3 at its second end 532. The piston 53, receiving the large pressure in the pressurizing chamber 520, moves at high speed away from the igniter 51 (downward in Figure 1), pushing the movable contact 3. The piston 53 is moved by the pressure in the pressurizing chamber 520 from a first position (position shown in Figure 1) to a second position (position shown in Figure 7). The movement of the piston 53 from the first position to the second position causes the pressurizing chamber 520 (the space in the case 52 where the gas from the igniter 51 is introduced and the pressure rises) to expand.

[0025] The movable contact 3 is pushed by the piston 53 and moves within the housing chamber 70. As the movable contact 3 moves by the piston 53, the first movable contact 31 is pulled away from the first fixed contact 11 and the second movable contact 32 is pulled away from the second fixed contact 21, as shown in Figures 6 and 7. This disconnects the electrical circuit between the first electrode 12 and the second electrode 22. Thus, in this embodiment, the pressurizing chamber 520 and the piston 53 function as a moving mechanism that moves the movable contact 3 from a position where the movable contact (first movable contact) 31 is connected to the fixed contact (first fixed contact) 11 to a position where the movable contact is separated from the fixed contact.

[0026] In the following, the position of the movable contact 3 where the first movable contact 31 is furthest from the first fixed contact 11 (the position of the movable contact 3 shown in Figure 7) is referred to as the open position. In the open position, the second movable contact 32 is also far from the second fixed contact 21.

[0027] As shown in Figure 1, a flow path 50 is formed in the side wall of the case 52, connecting the inside and outside of the case 52. The first end 501 of the flow path 50 is connected to the housing chamber 70, and the second end 502 of the flow path 50 is connected to the internal space of the case 52. However, when the piston 53 is in the first position, the second end 502 of the flow path 50 is not connected to the pressurizing chamber 520 (see Figure 1).

[0028] As the piston 53 moves from the first position (see Figure 1) to the second position (see Figure 7), the pressurized chamber 520 expands, and the second end 502 of the flow path 50 connects to the pressurized chamber 520. As a result, the pressurized chamber 520 and the containment chamber 70 are connected via the flow path 50. Therefore, the gas generated in the igniter 51 is introduced into the containment chamber 70 through the pressurized chamber 520 and the flow path 50.

[0029] The containment chamber 70 houses the first fixed contact 11 and the first movable contact 31. Here, as described above, the gas generated by the igniter 51 is introduced into the containment chamber 70. As a result, the arc generated between the fixed contact (first fixed contact) 11 and the movable contact (first movable contact) 31 (a predetermined space S1) is cooled by the gas generated by the igniter 51. "Arc cooling" here means increasing the insulating properties of the plasma or metal vapor of the arc discharge. Arc cooling is achieved, for example, by increasing the pressure in the predetermined space S1 by introducing an electrically insulating gas, or by blowing an electrically insulating gas onto the arc. When the arc is cooled, the electric field strength of the arc (voltage per unit length) increases, the length of the arc that can exist while a certain voltage is applied to both ends of the arc is shortened, and the arc extinction is promoted.

[0030] Thus, in the circuit breaker 100, when the movable contact (first movable contact) 31 is pulled away from the fixed contact (first fixed contact) 11, the gas generated by the igniter 51 is introduced into the containment chamber 70 (specifically, the predetermined space S1). As a result, if an arc occurs between the contacts, the arc is cooled by the gas. Therefore, the circuit breaker 100 is able to quickly extinguish the arc.

[0031] (1.2) Details The circuit breaker 100 of this embodiment will be described in detail below with reference to Figures 1 to 7.

[0032] (1.2.1) Power System As shown in Figure 5, the circuit breaker 100 of this embodiment is used, for example, as a fuse in a power supply system 200.

[0033] The power supply system 200 is mounted on a vehicle 300, such as an electric vehicle, and drives a motor 3002 connected via an inverter 3001 to move the vehicle 300. In the vehicle 300, as shown in Figure 5, a pre-charge capacitor 3003 is connected in parallel with the inverter 3001.

[0034] During powering, the inverter 3001 converts the DC power supplied from the power supply system 200 into AC power and supplies it to the motor 3002. During regeneration, it converts the AC power supplied from the motor 3002 into DC power and supplies it to the power supply system 200. The motor 3002 is, for example, a three-phase AC synchronous motor.

[0035] In addition to the circuit breaker 100, the power supply system 200 includes a battery 201, a first main relay 202, a second main relay 203, a precharge resistor 204, a precharge relay 205, a current sensor (shunt resistor) 206, and a control circuit 207.

[0036] Battery 201 comprises multiple battery cells connected in series. The battery cells can be, for example, nickel-metal hydride cell cells, lithium-ion cell cells, etc.

[0037] The first terminal of the first main relay 202 is connected to the positive terminal of the battery 201, and the second terminal is connected to the first input terminal (high-potential side input terminal) of the inverter 3001.

[0038] The first end of the second main relay 203 is connected to the negative terminal of the battery 201 via the current sensor 206 and the circuit breaker 100, and the second end is connected to the second input terminal (low-potential side input terminal) of the inverter 3001.

[0039] A series circuit consisting of a precharge resistor 204 and a precharge relay 205 is connected in parallel with the first main relay 202.

[0040] The control circuit 207 controls the operation of the first main relay 202, the second main relay 203, the precharge relay 205, and the circuit breaker 100.

[0041] When power is first supplied to the motor 3002, the control circuit 207 closes the precharge relay 205 and the second main relay 203 to charge the precharge capacitor 3003. This suppresses the inrush current to the motor 3002. After the precharge capacitor 3003 has finished charging, the control circuit 207 opens the precharge relay 205 and closes the first main relay 202 to start supplying power from the power supply system 200.

[0042] Furthermore, the control circuit 207 detects the occurrence of an abnormality in the circuit including the power supply system 200 based on the current detected by the current sensor 206. When an abnormality occurs in the circuit including the power supply system 200, the control circuit 207 activates (starts) at least one of the first main relay 202, the second main relay 203, and the circuit breaker 100 to shut off the circuit.

[0043] The control circuit 207 opens at least one of the first main relay 202 and the second main relay 203 if, for example, the magnitude of the current detected by the current sensor 206 exceeds a first threshold for a period of time. This interrupts the circuit. In this case, if the control circuit 207 closes the opened relays (first main relay 202, second main relay 203) again, the circuit is re-established and the supply of power from the power supply system 200 to the motor 3002 is resumed.

[0044] On the other hand, the control circuit 207 activates the circuit breaker 100 if, for example, the magnitude of the current detected by the current sensor 206 exceeds the second threshold (> first threshold) for two consecutive hours. This interrupts the circuit. The circuit breaker 100 is a circuit breaker that interrupts the circuit. Once activated, the circuit breaker 100 continues to interrupt the circuit, so after the circuit breaker 100 is activated, the power supply from the power system 200 to the motor 3002 is stopped. Therefore, in the event of an accident involving the vehicle 300, the circuit breaker 100 can be activated to shut off the power system 200.

[0045] (1.2.2) Configuration Next, the configuration of the circuit breaker 100 will be explained with reference to Figures 1 to 4.

[0046] As described above, the circuit breaker 100 includes a first fixed terminal 1, a second fixed terminal 2, a movable contact 3, a holding part 4, and a pyro actuator 5. Furthermore, as shown in Figure 1, the circuit breaker 100 includes a first yoke (lower yoke) 61, a second yoke (upper yoke) 62, and a housing 7 having a hoisting chamber 70.

[0047] The movable contact 3 in this embodiment is a plate-shaped member made of a conductive metal material and is formed to be elongated in one direction. The movable contact 3 has a first movable contact 31 at its first longitudinal end and a second movable contact 32 at its second end. The first fixed terminal 1 and the second fixed terminal 2 are arranged side by side along the longitudinal direction of the movable contact 3. The first fixed terminal 1 has a first fixed contact 11 at a position opposite to the first movable contact 31 of the movable contact 3, and the second fixed terminal 2 has a second fixed contact 21 at a position opposite to the second movable contact 32 of the movable contact 3.

[0048] For the sake of explanation, in the following, the direction in which the first fixed contact 11 and the first movable contact 31 face each other (the direction in which the second fixed contact 21 and the second movable contact 32 face each other; the up and down direction in Figure 1) will be defined as the up and down direction, and the first fixed contact 11 side will be considered upwards when viewed from the first movable contact 31. Also, the direction in which the first fixed terminal 1 and the second fixed terminal 2 are aligned (the left and right direction in Figure 1) will be defined as the left and right direction, and the second fixed terminal 2 side will be considered to the right when viewed from the first fixed terminal 1. In other words, in the following, the up, down, left and right directions in Figure 1 will be described as up, down, left and right. Furthermore, in the following, the direction perpendicular to both the up and down direction and the left and right direction (the direction perpendicular to the plane of the paper in Figure 1) will be described as the front and back direction. However, these directions are not intended to limit the usage of the circuit breaker 100.

[0049] The first fixed terminal 1 and the second fixed terminal 2 are arranged side by side in the left-right direction (see Figure 1). Each of the first fixed terminal 1 and the second fixed terminal 2 is made of a conductive metal material. The first fixed terminal 1 and the second fixed terminal 2 function as terminals for connecting external electrical circuits (circuits constituting the power supply system 200 described above) to the first fixed contact 11 and the second fixed contact 21. In this embodiment, each of the first fixed terminal 1 and the second fixed terminal 2 is formed of copper (Cu) as an example. However, it is not limited to this, and each of the first fixed terminal 1 and the second fixed terminal 2 may be formed of a conductive material other than copper.

[0050] As shown in Figure 2, the first fixed terminal 1 integrally includes a connecting piece 110, an electrode piece 120, a linking piece 130, and a circuit piece 140.

[0051] The connecting piece 110 is a rectangular plate shape that has thickness in the vertical direction and is long in the front-to-back direction. In this embodiment, the lower surface of the connecting piece 110 functions as the first fixed contact 11, but is not limited to this. The first fixed contact 11 may be made of a separate component from the connecting piece 110 and fixed to the connecting piece 110 by welding or the like.

[0052] The electrode piece 120 is plate-shaped with thickness in the front-to-back direction. The electrode piece 120 is square-shaped and has a through hole in the center. The electrode piece 120 is connected to the first end of the external electrical circuit. In other words, the electrode piece 120 functions as the first electrode 12 connected to the first end of the external electrical circuit.

[0053] The connecting piece 130 is a rectangular plate shape that is thick in the left-right direction and long in the vertical direction. The lower side of the connecting piece 130 is connected to the left side of the connecting piece 110.

[0054] The circuit piece 140 is plate-shaped with thickness in the front-to-back direction. The circuit piece 140 connects the electrode piece 120 and the connecting piece 130. The left side of the circuit piece 140 is connected to the upper part of the right side of the electrode piece 120. The right side of the circuit piece 140 is connected to the center of the left side of the connecting piece 130.

[0055] As shown in Figure 2, the second fixed terminal 2 integrally includes a connecting piece 210, an electrode piece 220, a linking piece 230, and a circuit piece 240.

[0056] The connecting piece 210 is a rectangular plate shape that has thickness in the vertical direction and is long in the front-to-back direction. In this embodiment, the lower surface of the connecting piece 210 functions as the second fixed contact 21, but is not limited to this. The second fixed contact 21 may be made of a separate component from the connecting piece 210 and fixed to the connecting piece 210 by welding or the like.

[0057] The electrode piece 220 is plate-shaped with thickness in the front-to-back direction. The electrode piece 220 is square-shaped and has a through hole in the center. The electrode piece 220 is connected to the second end of the external electrical circuit. In other words, the electrode piece 220 functions as a second electrode 22 connected to the second end of the external electrical circuit.

[0058] The connecting piece 230 is a rectangular plate shape that is thick in the left-right direction and long in the vertical direction. The lower side of the connecting piece 230 is connected to the right side of the connecting piece 210.

[0059] The circuit piece 240 is plate-shaped with thickness in the front-to-back direction. The circuit piece 240 connects the electrode piece 220 and the connecting piece 230. The right side of the circuit piece 240 is connected to the upper part of the left side of the electrode piece 220. The left side of the circuit piece 240 is connected to the center of the right side of the connecting piece 230.

[0060] As shown in Figure 1, the first fixed terminal 1 is fixed to the housing 7 with the electrode piece 120 exposed to the outside from the left wall of the housing 7, and the lower end of the connecting piece 130 and the connecting piece 110 housed within the internal space (housing chamber 70) of the housing 7. The second fixed terminal 2 is fixed to the housing 7 with the electrode piece 220 exposed to the outside from the right wall of the housing 7, and the lower end of the connecting piece 230 and the connecting piece 210 housed within the internal space (housing chamber 70) of the housing 7.

[0061] As shown in Figures 1 to 3, the movable contact 3 is formed in a plate shape that has thickness in the vertical direction and is longer in the left-right direction than in the front-back direction. The movable contact 3 is positioned below the connecting pieces 110 and 210 so that both ends of its longitudinal direction (left-right direction) face (connect) to the first fixed contact 11 and the second fixed contact 21 (see Figure 1). Of the movable contact 3, the portion facing the first fixed contact 11 is provided with the first movable contact 31, and the portion facing the second fixed contact 21 is provided with the second movable contact 32 (see Figure 1).

[0062] In this embodiment, the first movable contact 31 is in contact with the first fixed contact 11. More specifically, the first movable contact 31 is in surface contact with the first fixed contact 11. Also, the second movable contact 32 is in contact with the second fixed contact 21. More specifically, the second movable contact 32 is in surface contact with the second fixed contact 21.

[0063] In this embodiment, the first movable contact 31 is a separate component from the movable contact 3, made of silver (Ag), and is fixed to the movable contact 3 by welding or the like. Similarly, the second movable contact 32 is a separate component from the movable contact 3, made of silver (Ag), and is fixed to the movable contact 3 by welding or the like. However, it is not limited to this, and each of the first movable contact 31 and the second movable contact 32 may be integrally constructed with the movable contact 3, for example, by having a part of the movable contact 3 punched out.

[0064] As shown in Figure 1, the movable contact 3 is housed in the internal space (housing chamber 70) of the housing 7. The movable contact 3 is held by the holding part 4 such that the first movable contact 31 is connected to the first fixed contact 11 and the second movable contact 32 is connected to the second fixed contact 21.

[0065] The first fixed terminal 1 and the second fixed terminal 2 are short-circuited via the movable contact 3. That is, the first electrode 12 of the first fixed terminal 1 is electrically connected to the second electrode 22 of the second fixed terminal 2 via the first fixed contact 11, the first movable contact 31, the movable contact 3, the second movable contact 32, and the second fixed contact 21 (see Figure 2). Therefore, when the first electrode 12 is electrically connected to the first end of the electrical circuit and the second electrode 22 is electrically connected to the second end, the circuit breaker 100 forms an electrical circuit between the first electrode 12 and the second electrode 22.

[0066] As shown in Figures 1 and 3, the housing 7 comprises an inner cylinder 71, an outer cylinder 72, and a lid member 73.

[0067] The inner cylinder 71 is made of an electrically insulating material, such as a resin material. The inner cylinder 71 is formed in a closed-bottom cylindrical shape with a closed bottom and an open top. A cylindrical retaining rib 711 is provided on the upper surface of the lower wall of the inner cylinder 71 (the bottom surface of the inner cylinder 71). The retaining rib 711 is formed concentrically with the inner cylinder 71.

[0068] The outer cylinder 72 is formed from, for example, a metal material. Preferably, the outer cylinder 72 is made from a non-magnetic metal material. Examples of non-magnetic metal materials include austenitic stainless steel such as SUS304. However, the material of the outer cylinder 72 does not have to be non-magnetic; for example, it may be an alloy mainly composed of iron, such as 42 alloy.

[0069] The outer cylinder 72 is concentric with the inner cylinder 71 and is formed as a bottomed cylindrical shape with a closed bottom and an open top. The outer cylinder 72 is provided so as to cover the periphery of the inner cylinder 71. In other words, the outer cylinder 72 is a reinforcing member that improves the strength of the housing 7 (the strength of the outer wall of the housing chamber 70).

[0070] The inner cylinder 71 may be formed integrally with the outer cylinder 72, for example, by insert molding. Furthermore, the housing 7 does not necessarily have to include the outer cylinder 72.

[0071] The lid member 73 is formed from an electrically insulating material, such as a resin material. The lid member 73 is formed in a closed-bottom cylindrical shape with a closed top and an opening at the bottom. The lid member 73 is formed integrally with the first fixing terminal 1 and the second fixing terminal 2, for example by insert molding.

[0072] The thickness of the upper wall of the lid member 73 is greater than the thickness of the side walls of the lid member 73. A through hole 731 is formed in the center of the upper wall of the lid member 73, concentric with the lid member 73. The pyro actuator 5 is positioned within the through hole 731 of the lid member 73. The lower end of the pyro actuator 5 protrudes from the lower surface (inner surface) of the upper wall of the lid member 73. The through hole 731 is airtightly sealed by the pyro actuator 5 (and its case 52).

[0073] An annular groove 732 is formed on the lower surface of the side wall of the lid member 73. The upper edges of the inner cylinder 71 and the outer cylinder 72 are inserted into the groove 732, thereby connecting the inner cylinder 71 and the outer cylinder 72 to the lid member 73. As a result, the housing 7 has an airtight internal space (housing chamber 70) surrounded by the inner cylinder 71 and the lid member 73. The first fixed contact 11, the second fixed contact 21, and the movable contact 3 are housed within the internal space (housing chamber 70) of the housing 7.

[0074] In this embodiment, the housing 7 is substantially cylindrical with an internal space (housing chamber 70), but is not limited to this. The housing 7 may have any shape that has an internal space (housing chamber 70) for housing the first fixed contact 11, the second fixed contact 21, and the movable contact 3, and may have other shapes such as a hollow polygonal prism (for example, a hollow rectangular parallelepiped).

[0075] The first yoke 61 is a ferromagnetic material, for example, made of a metallic material such as iron. The first yoke 61 is fixed to the lower surface of the movable contact 3 and is integrated with the movable contact 3 (see Figures 1 and 3). In other words, the first yoke 61 is fixed to the side of the movable contact 3 opposite to the side where the first movable contact 31 and the second movable contact 32 are located.

[0076] The first yoke 61 acts on the magnetic field generated by the current flowing through the movable contact 3 so that the magnetic field passes through the first yoke 61. In other words, without the first yoke 61, a magnetic field (concentric) is generated centered on the current flowing through the movable contact 3, but with the first yoke 61, the magnetic field changes so that it passes through the first yoke 61. Therefore, the magnetic field acting on the current flowing through the movable contact 3 is induced to have its center on the side where the first movable contact 31 and the second movable contact 32 are located (i.e., the upper surface), and as a result, a relative upward force is generated on the movable contact 3. For this reason, with the first yoke 61, the connection between the first movable contact 31 and the second movable contact 32 and the first fixed contact 11 and the second fixed contact 21 is easier to maintain compared to when the first yoke 61 is not present.

[0077] A cylindrical recessed fitting recess 610 is formed on the lower surface of the first yoke 61.

[0078] The second yoke 62 is made of a ferromagnetic material, such as iron. The second yoke 62 is fixed in a position opposite the first yoke 61, with the movable contact 3 in between, but separated from the movable contact 3. The second yoke 62 may also be in contact with the second end 532 (lower end) of the piston 53 of the pyroactuator 5. In this embodiment, the second yoke 62 is fixed to the second end 532 (lower end) of the piston 53 of the pyroactuator 5. The second yoke 62 is positioned so as to face the central portion of the movable contact 3 (see Figure 2), but with a gap between it and the movable contact 3 so as not to be in contact (see Figure 3). The second yoke 62 is electrically insulated from the movable contact 3.

[0079] The second yoke 62 has a pair of upwardly projecting protrusions 621 and 622 (see Figure 3) at both ends in the front-rear direction. In other words, the upper surface of the second yoke 62 has protrusions 621 and 622 at both ends in the front-rear direction that face the front-rear side surfaces of the movable contact 3. As shown in Figure 3, the tip surface (lower end surface) of the front protrusion 621 of the pair of protrusions 621 and 622 abuts against the front end of the first yoke 61, and the tip surface (lower end surface) of the rear protrusion 622 abuts against the rear end of the first yoke 61. Therefore, when current flows between the first fixed terminal 1 and the second fixed terminal 2 through the movable contact 3, a magnetic flux is generated through the magnetic path formed by the first yoke 61 and the second yoke 62. At this time, the front end of the first yoke 61 and the projection 621 at the front end of the second yoke 62 are magnetized to opposite poles, and the rear end of the first yoke 61 and the projection 622 at the rear end of the second yoke 62 are magnetized to opposite poles. As a result, an attractive force acts between the first yoke 61 and the second yoke 62. Since the second yoke 62 is fixed to the second end 532 (lower end) of the piston 53, the first yoke 61 is pulled upward by this attractive force. As the first yoke 61 is pulled upward, an upward force acts on the movable contact 3 from the first yoke 61.

[0080] When current flows through the movable contact 3, this current can generate an electromagnetic repulsive force that separates the first movable contact 31 and the second movable contact 32 from the first fixed contact 11 and the second fixed contact 21. In other words, when current flows through the movable contact 3, the Lorentz force can cause an electromagnetic repulsive force to act on the movable contact 3 in a direction that moves it downward.

[0081] In this embodiment, as described above, the magnetic field changes to pass through the first yoke 61, resulting in an upward force compared to the absence of the first yoke 61. In addition, the attractive force described above acts between the first yoke 61 and the second yoke 62. As a result, the current flowing through the movable contact 3 exerts an upward force on the movable contact 3, that is, a force that presses the first movable contact 31 and the second movable contact 32 against the first fixed contact 11 and the second fixed contact 21, respectively.

[0082] As described above, the first yoke 61 and the second yoke 62 function as a connection maintenance mechanism, generating a force through the current flowing through the movable contact 3 that maintains the connection between the first movable contact 31 and the second movable contact 32 and the first fixed contact 11 and the second fixed contact 21.

[0083] Spacers 631 and 632, made of an electrically insulating material, such as a resin material, are positioned between the protrusions 621 and 622 of the second yoke 62 and both ends in the front-rear direction of the upper surface of the first yoke 61 (see Figure 3). This ensures electrical insulation between the second yoke 62 and the first yoke 61.

[0084] As shown in Figures 1 and 3, the holding part 4 of this embodiment is equipped with a contact pressure spring 41. The contact pressure spring 41 is a coil spring. The contact pressure spring 41 is positioned between the bottom surface (inner surface) of the inner cylinder 71 and the lower surface of the first yoke 61. The coil axis of the contact pressure spring 41 is aligned in the vertical direction. The holding rib 711 of the inner cylinder 71 is inserted inside the first end 411 of the contact pressure spring 41. The second end 412 of the contact pressure spring 41 is inserted into the fitting recess 610 of the first yoke 61. The contact pressure spring 41 applies an upward elastic force to the movable contact 3 via the first yoke 61. In other words, the circuit breaker 100, as the holding part 4, is equipped with an elastic part (contact pressure spring 41) that applies an elastic force to the movable contact 3 in the direction in which the movable contact (first movable contact) 31 is connected to the fixed contact (first fixed contact) 11 (towards the closed position).

[0085] The contact pressure spring 41 pushes the movable contact 3 upward via the first yoke 61. The contact pressure spring 41 holds the movable contact 3 such that the first movable contact 31 is connected to the first fixed contact 11 and the second movable contact 32 is connected to the second fixed contact 21.

[0086] Figure 4 shows a cross-sectional view of the pyroactuator 5 of this embodiment. The pyroactuator 5 of this embodiment has a so-called pin pusher structure in which the piston 53 (pin 535) is pushed out by the gas generated by the igniter 51.

[0087] As shown in Figure 4, the pyroactuator 5 comprises an igniter 51, a case 52 having a pressurized chamber 520 inside, and a piston 53.

[0088] The igniter 51 comprises a body 511, a metal sleeve (metal CAN) 512, a combustion section 513, a pair of pin electrodes 514, and a heating element 515.

[0089] The body 511 is formed from, for example, an electrically insulating resin material, and is formed in a bottomed cylindrical shape with an open top and a closed bottom. The internal space 5110 of the body 511 is sealed with an electrically insulating sealing material, such as glass.

[0090] The metal sleeve 512 is made of a metal such as stainless steel and integrally comprises a cylindrical portion with a bottom that is open at the top and closed at the bottom, and a flange portion that protrudes laterally from the upper end of the cylindrical portion. In the center of the lower wall of the metal sleeve 512 (the cylindrical portion), a cross groove or the like is formed, which is not deep enough to penetrate the lower wall. In other words, a portion of the lower wall of the metal sleeve 512 is a low-strength portion that is weaker (more prone to breakage) than other parts of the metal sleeve 512. The metal sleeve 512 is joined to the body 511 by adhesive or the like at the flange portion so as to cover the lower surface of the body 511.

[0091] The combustion section 513 contains an explosive, such as nitrocellulose. The combustion section 513 is located within a space enclosed by the body 511 and the metal sleeve 512. The explosive contained in the combustion section 513 can be any material that generates an electrically insulating gas upon combustion, and is not limited to nitrocellulose.

[0092] Each of the pair of pin electrodes 514 has its first end located inside the combustion chamber 513 (in the space enclosed by the body 511 and the metal sleeve 512) and its second end exposed to the outside of the pyro actuator 5 through the body 511. The second ends of the pair of pin electrodes 514 are connected to the control circuit 207.

[0093] The heating element 515 is an element that generates heat when an electric current is passed through it, and in this embodiment it is a nichrome wire. The heating element 515 is located inside the combustion section 513 (in the space surrounded by the body 511 and the metal sleeve 512). The heating element 515 is connected between the first ends of a pair of pin electrodes 514.

[0094] In the igniter 51, when current from the control circuit 207 energizes the pair of pin electrodes 514, the heating element 515 heats up, and the temperature of the combustion section 513 rises. When the temperature of the combustion section 513 (the part surrounding the heating element 515) exceeds the ignition temperature, the gunpowder burns explosively, instantly generating a large amount of gas (e.g., carbon monoxide, carbon dioxide, nitrogen). When the pressure inside the combustion section 513 exceeds the pressure resistance of the low-strength section of the metal sleeve 512 due to the generation of gas, the low-strength section ruptures, and the gas generated by combustion is released to the outside (in this embodiment, the lower pressurized chamber 520) through the ruptured section.

[0095] As shown in Figure 4, the piston 53 comprises a base 533, a cylinder 534, a pin (rod) 535, and a spring 536.

[0096] The base 533 is formed from an electrically insulating material such as resin, for example, polycarbonate or polybutylene terephthalate. The base 533 has three cylindrical columns, a first column, a second column, and a third column, in that order from top to bottom, with the first, second, and third columns connected vertically (concentrically). The outer diameter of the first column is larger than that of the second column, and the outer diameter of the second column is larger than that of the third column. On the outer surface of the base 533, an annular retaining groove 5330 is formed at the boundary between the first and second columns, and is concentric with the first and second columns.

[0097] In this embodiment, the bottom surface (top surface) of the first column portion of the base 533 is the first end 531 of the piston 53.

[0098] The cylinder 534 is formed from an electrically insulating material, such as resin. The cylinder 534 is cylindrical in shape. The inner diameter of the cylinder 534 is approximately equal to the outer diameter of the third column of the base 533, and smaller than the outer diameter of the second column. The outer diameter of the cylinder 534 is smaller than the outer diameter of the second column of the base 533. The third column of the base 533 is fitted into the upper opening of the cylinder 534, thereby joining the cylinder 534 and the base 533.

[0099] The pin 535 is formed from an electrically insulating material such as resin, for example, polycarbonate or polybutylene terephthalate. The pin 535 has a cylindrical large-diameter portion and a small-diameter portion from top to bottom, and the large-diameter portion and the small-diameter portion are connected vertically (concentrically). The axial length (vertical direction) of the large-diameter portion of the pin 535 is approximately the same as the length of the cylinder 534. Specifically, the length of the pin 535 is slightly greater than the distance between the bottom surface (lower surface) of the base 533 connected to the cylinder 534 and the lower end of the cylinder 534. As shown in Figure 1, the small-diameter portion of the pin 535 is fixed in the through hole of the second yoke 62. In this embodiment, the region including the small-diameter portion of the pin 535 is the second end 532 of the piston 53.

[0100] As shown in Figure 4, the spring 536 is a coil spring. The spring 536 defines the relative position between the cylinder 534 and the pin 535. Specifically, the spring 536 is sandwiched between the inner surface of the cylinder 534 and the outer surface of the pin 535, holding the pin 535 inside the cylinder 534.

[0101] The case 52 comprises a holder 521, a sleeve 522, a cap 523, a first retaining spring 524, and a second retaining spring 525. The case 52 is formed in a substantially cylindrical shape overall.

[0102] The holder 521 of case 52 is made of metal, for example, aluminum or an aluminum alloy. The holder 521 is formed in a substantially cylindrical shape with an open top and bottom, and its inner surface is formed in a multi-stage cylindrical shape. The holder 521 holds the igniter 51 and the piston 53.

[0103] The igniter 51 is fitted into the space in the upper part of the holder 521 of the case 52. The inner surface of the upper part of the holder 521 has a shape that is in close contact with the outer surface of the igniter 51 (the outer surface of the body 511, the outer surface of the flange of the metal sleeve 512, and the outer surface of the cylindrical part of the metal sleeve 512). The upper opening of the holder 521 (internal space) is closed by the igniter 51.

[0104] The base 533 of the piston 53 is fitted into the space in the lower part of the holder 521 of the case 52. The inner surface of the lower part of the holder 521 has a shape that is almost in close contact with the outer surface of the first column of the base 533. The lower opening of the holder 521 (internal space) is closed by the piston 53 (base 533).

[0105] By mounting the igniter 51 and piston 53 to the case 52, a closed, airtight space is formed between the lower surface of the igniter 51 (its metal sleeve 512), the upper surface of the piston 53 (its base 533), and the inner surface of the case 52 (its holder 521). The gas generated in the igniter 51 is introduced into this airtight space through the broken portion of the lower wall of the metal sleeve 512. In other words, this airtight space functions as a pressurized chamber 520 that receives the pressure of the gas generated in the igniter 51.

[0106] The sleeve 522 of case 52 is made of metal, for example, steel. The sleeve 522 is positioned below the holder 521, with its outer surface continuous with the outer surface of the holder 521. The sleeve 522 is formed in a substantially cylindrical shape with an open top and bottom. The sleeve 522 has three cylindrical sections, a first cylindrical section, a second cylindrical section, and a third cylindrical section, in that order from top to bottom, and the first, second, and third cylindrical sections are connected vertically (concentrically). The inner surface of the first cylindrical section is tapered, with the diameter decreasing towards the bottom. The inner surface of the second cylindrical section is formed in a cylindrical shape with a constant diameter. The inner diameter of the second cylindrical section is approximately equal to the outer diameter of the first column (the largest diameter part) of the base 533 of the piston 53. The inner surface of the third cylindrical section is tapered, with the diameter decreasing towards the bottom. The diameter of the inner surface of the third cylindrical section is approximately equal to the outer diameter of the first column of the base 533 (the part of the base 533 with the largest diameter) at its upper end, and decreases towards the bottom. In other words, the third cylindrical section of the sleeve 522 is shaped in such a way that the base 533 of the piston 53 cannot pass through its interior.

[0107] Two flow channels 50 connecting the inside and outside of the case 52 are formed in the side wall of the sleeve 522 of the case 52. As shown in Figure 1, the first end 501 of each flow channel 50 is connected to the housing chamber 70, and the second end 502 is connected to the internal space of the case 52. Each flow channel 50 is cylindrical with a constant diameter. One of the two flow channels 50 (the flow channel 50 on the left in Figure 1) is formed in the side wall of the sleeve 522 of the case 52 in the portion facing the first fixed terminal 1. This flow channel 50 guides the gas generated by the igniter 51 so that it is blown into a predetermined space S1 between the first movable contact 31 and the first fixed contact 11 (the space including the movement trajectory when the first movable contact 31 moves, see Figure 7). In other words, the gas generated by the igniter 51 is introduced into a predetermined space S1 between the fixed contact (first fixed contact) 11 and the movable contact (first movable contact) 31 when the movable contact 3 is in the open position. The other of the two flow paths 50 (the flow path 50 on the right in Figure 1) is formed in the side wall of the sleeve 522 of the case 52, in the portion facing the second fixed terminal 2. This flow path 50 guides the gas generated by the igniter 51 so that it is blown into a predetermined space S2 between the second movable contact 32 and the second fixed contact 21 (the space including the movement trajectory when the second movable contact 32 moves). Each of the two flow paths 50 extends diagonally downward from the inside to the outside of the case 52.

[0108] In this embodiment, each flow path 50 is straight. However, the shape of the flow path 50 is not particularly limited and may be other shapes, such as curved. Also, the diameter of the flow path 50 is not particularly limited. Furthermore, the direction in which the flow path 50 extends is not particularly limited and may extend laterally (horizontally). Furthermore, the position in which the flow path 50 is formed is not particularly limited and may be formed, for example, in the front or rear portion of the side wall of the sleeve 522 of the case 52. However, it is preferable that each flow path 50 is formed in a shape, diameter, direction and position that allows the gas generated by the igniter 51 to be blown into a predetermined space S1 or predetermined space S2.

[0109] The cap 523 of case 52 is made of metal, for example, steel. The cap 523 is positioned below the sleeve 522, with its outer surface continuous with the outer surface of the sleeve 522. The cap 523 is formed in a cylindrical shape with both its upper and lower surfaces open. A projection (flange) is formed on the lower surface of the cap 523, projecting inward. The inner diameter of the projection (flange) is approximately equal to the outer diameter of the cylinder 534 of the piston 53. The piston 53 is an operating pin that moves in one direction in response to the pressure of the gas generated in the igniter 51.

[0110] In this embodiment, the outer diameters of the holder 521, sleeve 522, and cap 523 are equal.

[0111] The first retaining spring 524 has a hollow disc-shaped clamped portion and a hollow frustoconical retaining portion that protrudes diagonally upward from the inner surface of the clamped portion. The clamped portion of the first retaining spring 524 is sandwiched between the holder 521 and the sleeve 522 of the case 52, thereby clamping the first retaining spring 524 between the holder 521 and the sleeve 522. The first retaining spring 524 seals the gap at the boundary between the holder 521 and the sleeve 522. The retaining portion contacts the retaining groove 5330 of the base 533 of the piston 53, applying an upward force to the base 533 and holding the base 533 (preventing the base 533 from moving downward).

[0112] The second retaining spring 525 has a hollow disc-shaped clamped portion and a hollow frustoconical retaining portion that protrudes diagonally downward from the inner surface of the clamped portion. The clamped portion of the second retaining spring 525 is sandwiched between the sleeve 522 and the cap 523 of the case 52, thereby sandwiching the second retaining spring 524 between the sleeve 522 and the cap 523. The second retaining spring 525 seals the gap at the boundary between the sleeve 522 and the cap 523. The protruding tip of the retaining portion is away from the outer surface of the cylinder 534 of the piston 53. The diameter of the protruding tip of the retaining portion is approximately equal to the outer diameter of the second column portion of the base 533 of the piston 53.

[0113] As shown in Figure 4, when the igniter 51 and piston 53 are assembled in the case 52, the pin electrode 514 of the igniter 51 protrudes from the upper surface of the case 52. Also, the small diameter portion of the pin 535 protrudes downward from the lower surface of the case 52.

[0114] As shown in Figure 1, the pyro actuator 5 is mounted to the housing 7 such that the case 52 closes the through hole 731 of the cover member 73. In this state, the second end of the piston 53 (the lower end of the pin 535) faces the center (the center in the longitudinal and transverse directions) of the movable contact 3.

[0115] (1.2.3) Operation Next, the operation of the circuit breaker 100 with the above configuration will be explained based on Figures 1, 6, and 7.

[0116] The circuit breaker 100 has a first electrode 12 connected to the first end of an electrical circuit (for example, a circuit constituting the power supply system 200) and a second electrode 22 connected to the second end of the electrical circuit. Here, the first end of the electrical circuit is at a higher potential than the second end.

[0117] Under normal electrical conditions, the movable contactor 3 is held in place by the spring force of the contact pressure spring 41, such as the spring force of the contact pressure spring 41, so that the first movable contact 31 is connected to the first fixed contact 11 and the second movable contact 32 is connected to the second fixed contact 21 (see Figure 1). In other words, under normal electrical conditions, the movable contactor 3 is in a closed position where the first movable contact 31 is in contact with the first fixed contact 11 and the second movable contact 32 is in contact with the second fixed contact 21. At this time, current flows from the first electrode 12 through the first fixed contact 11, the first movable contact 31, the movable contactor 3, the second movable contact 32, and the second fixed contact 21 in that order towards the second electrode 22.

[0118] At this time, the contact between the first movable contact 31 and the first fixed contact 11, and the contact between the second movable contact 32 and the second fixed contact 21 are maintained by the spring force of the contact pressure spring 41, the attractive force between the first yoke 61 and the second yoke 62, etc. Furthermore, even if an overcurrent flows through the circuit breaker 100, if its magnitude is relatively small, the contact between the contacts is maintained by the attractive force between the first yoke 61 and the second yoke 62, etc.

[0119] If the current flowing through the electrical circuit exceeds a specified value (an abnormality in the electrical circuit), the control circuit 207, for example, will detect this abnormal current. Upon detecting the abnormal current, the control circuit 207 will activate (start) the circuit breaker 100 to shut off the electrical circuit.

[0120] Specifically, the control circuit 207 energizes the heating element 515 by passing an electric current between a pair of pin electrodes 514. When energized, the heating element 515 generates heat, raising the temperature of the combustion section 513. When the temperature of the combustion section 513 exceeds the ignition temperature of the gunpowder, the gunpowder burns, generating a large amount of gas. The pressure of the gas causes the low-strength portion of the lower wall of the metal sleeve 512 to rupture, and the gas is released into the pressurized chamber 520 through the ruptured portion. Because the combustion section 513 burns explosively and generates a large amount of gas, the pressure in the pressurized chamber 520 increases rapidly in a short time.

[0121] Initially, the piston 53 is in a first position (see Figure 1). The piston 53 is pushed downward by the pressure in the pressurizing chamber 520 at its first end 531 (upper surface of the base 533), and pushes the movable contact 3 downward at its second end 532 (pin 535). The piston 53 applies force to the portion of the movable contact 3 between the first movable contact 31 and the second movable contact 32, moving the movable contact 3 downward. While pushing the movable contact 3, the piston 53 moves to a second position (see Figure 7).

[0122] Specifically, in the piston 53, the bottom (top) surface of the base 533 receives pressure in the pressurizing chamber 520, and against the spring force of the first retaining spring 524, the base 533 begins to move downward together with the cylinder 534. At this time, the initial velocity of the base 533 (piston 53) is very large due to the large pressure in the pressurizing chamber 520. The pin 535 receives a downward force from the cylinder 534 via the spring 536 and begins to move downward slightly after the cylinder 534 begins to move downward. The pin 535, the second yoke 62, the first yoke 61, and the movable contact 3 are integrated, and the downward movement of the pin 535 pushes the movable contact 3 downward, causing it to move downward. Here, the pin 535 is also subjected to a force due to the elastic energy stored in the spring 536 after the base 533 begins to move downward, so a very large downward force is applied to the pin 535, and its initial velocity is also large.

[0123] When the downward force pushing the movable contact 3 exceeds the upward supporting force (such as the spring force of the contact spring 41 or the attractive force between the first yoke 61 and the second yoke 62), the movable contact 3 moves downward while compressing the contact spring 41 via the first yoke 61. As a result, the first movable contact 31 is pulled away from the first fixed contact 11, and the second movable contact 32 is pulled away from the second fixed contact 21 (see Figure 6). Consequently, the circuit between the first fixed terminal 1 and the second fixed terminal 2 is interrupted, and the current flowing through the circuit between the first fixed terminal 1 and the second fixed terminal 2 is interrupted.

[0124] The piston 53, the first yoke 61, the movable contact 3, and the second yoke 62 move downward as a single unit (hereinafter, for the sake of explanation, the unit consisting of the piston 53, the first yoke 61, the movable contact 3, and the second yoke 62 will be referred to as the "moving body"). The direction in which the piston 53 moves and the direction in which the movable contact 3 moves due to the piston 53 are the same. The moving body typically moves to the position where the contact pressure spring 41 is most compressed (second position) (see Figure 7). In other words, the movable contact 3 moves to an open position where the first movable contact 31 is separated from the first fixed contact 11 and the second movable contact 32 is separated from the second fixed contact 21. At this time, the base 533 of the piston 53 moves inside the third cylindrical part of the sleeve 522 of the case 52, pushing and expanding (deforming) the inner surface of the third cylindrical part. The kinetic energy of the moving body is converted into the elastic energy of the contact pressure spring 41, the thermal energy generated when the moving body collides with the bottom surface of the inner cylindrical body 71, etc.

[0125] When the contact pressure spring 41 is compressed, the moving body receives an upward force from the compressed contact pressure spring 41. However, upward movement of the moving body is prevented by the frictional force between the base 533 and the third cylindrical portion of the sleeve 522 of the case 52. As a result, the moving body stops at the position shown in Figure 7 (the second position). In other words, the third cylindrical portion functions as a return-prevention mechanism, mechanically holding the piston 53 after the movable contact 3 has moved, and preventing the piston 53 from returning to its original position (the first position).

[0126] Furthermore, the downward movement of the piston 53 (movement from the first position to the second position) expands the space (pressurized chamber 520) within the case 52 where gas from the igniter 51 is introduced and the pressure rises. As the pressurized chamber 520 expands, the second end 502 of each flow path 50 connects to the pressurized chamber 520, as shown in Figure 7. As a result, the pressurized chamber 520 and the containment chamber 70 are connected via the flow path 50, and the gas generated in the igniter 51 is introduced into the containment chamber 70 through the pressurized chamber 520 and the flow path 50. In this embodiment, the gas introduced into the containment chamber 70 is directed towards a predetermined space S1 between the first movable contact 31 and the first fixed contact 11, or a predetermined space S2 between the second movable contact 32 and the second fixed contact 21 (see arrow W1 in Figure 7).

[0127] In this case, if the first movable contact 31 is pulled away from the first fixed contact 11 while current is flowing through the movable contact 3, an arc may occur between the first movable contact 31 and the first fixed contact 11 (see dotted line A1 in Figure 8A). Similarly, if the second movable contact 32 is pulled away from the second fixed contact 21 while current is flowing through the movable contact 3, an arc may occur between the second movable contact 32 and the second fixed contact 21.

[0128] In contrast, the circuit breaker 100 of this embodiment increases the pressure in the containment chamber 70 by introducing gas (electrically insulating gas) generated by the igniter 51 of the pyro actuator 5 into the containment chamber 70. The containment chamber 70, together with the pressurizing chamber 520, forms a sealed space. The containment chamber 70 houses the fixed contact (first fixed contact) 11 and the movable contact (first movable contact) 31 and includes a predetermined space S1. The containment chamber 70 is also the space in which an arc is generated. By increasing the pressure in this containment chamber 70, the arc generated between the contacts is cooled, and the insulating properties of the arc discharge plasma or metal vapor are improved, thus promoting arc extinguishing.

[0129] Furthermore, in the circuit breaker 100 of this embodiment, the gas introduced into the containment chamber 70 from the flow path 50 is blown into a predetermined space S1 between the first movable contact 31 and the first fixed contact 11, or into a predetermined space S2 between the second movable contact 32 and the second fixed contact 21. This cools the arc generated between the contacts and promotes arc extinguishing.

[0130] More specifically, when the fixed contact (first fixed contact) 11 and the movable contact 3 are displaced from the closed position to the open position, in the initial stage of displacement from the closed position to the open position, a column of arc discharge is generated between the fixed contact (first fixed contact) 11 and the movable contact 3 (see dotted line A1 in Figure 8A). As the displacement from the closed position to the open position progresses, gas is introduced into the containment chamber 70, and the gas strikes the column of arc discharge. The pressure of the gas deforms the column of arc discharge, causing the arc to extend (see dotted line A2 in Figure 8B). Furthermore, the gas extends the arc, and in some cases the arc may be pressed against the wall of the inner cylinder 71 (see dotted line A3 in Figure 8C). In this way, the arc is shut off by the gas extending the arc. That is, by introducing the gas generated in the igniter 51 into the gap between the fixed contact (first fixed contact) 11 and the movable contact 3, the arc extinguishing is promoted and the shutoff performance can be improved. Furthermore, the arc generated between the second movable contact 32 and the second fixed contact 21 is also extended by the blowing of gas, thus promoting arc extinguishing.

[0131] Thus, in the circuit breaker 100 of this embodiment, the gas generated by the igniter 51 is introduced into the predetermined spaces S1 and S2, thereby enabling rapid extinguishing of the arc.

[0132] Furthermore, the inner wall (inner cylinder 71) of the housing 7 may be formed of a resin material (arc-extinguishing gas generating member) that releases arc-extinguishing gas when heated by the extended arc. The arc-extinguishing gas is, for example, a gas such as CO2, N2, or H2O. The arc-extinguishing gas makes it possible to quickly extinguish the arc.

[0133] (1.3) Variant A modified example of the circuit breaker 100 of Embodiment 1 will be described with reference to Figures 9 and 10. Hereinafter, the circuit breaker 100 of Embodiment 1 will also be referred to as the basic example of the circuit breaker 100 of Embodiment 1.

[0134] Figures 9 and 10 show cross-sectional views of one modified circuit breaker 100 before and after operation. For convenience, the first yoke 61 and the second yoke 62 are omitted from Figures 9 and 10. Also, the case 52 is simplified in Figures 9 and 10. However, the case 52 may be equipped with a second cylindrical portion (a portion having a frustoconical inner surface whose diameter decreases towards the bottom) and a third cylindrical portion (a portion having a cylindrical inner surface with a smaller diameter than the base 533 of the piston 53) as a return mechanism, similar to the circuit breaker 100 of Embodiment 1. In one modified circuit breaker 100, the piston 53 is a single molded product. In one modified circuit breaker 100, the shapes of the first fixed terminal 1 and the second fixed terminal 2 differ from those of the circuit breaker 100 of the basic example of Embodiment 1, but they may be the same.

[0135] In one modified version of the circuit breaker 100, the flow path 50 is a tapered cylindrical shape, with its diameter gradually narrowing from the inside of the case 52 to the outside (towards the housing chamber 70). In other words, the diameter of the first end 501 (the end on the housing chamber 70 side) of the flow path 50 is smaller than the diameter of the second end 502. As a result, the gas flow velocity from the second end 502 to the first end 501 increases within the flow path 50, and the gas flow velocity in the predetermined spaces S1 and S2 increases. Therefore, it becomes possible to more effectively cool the arc generated between the contacts and further promote arc extinguishing.

[0136] Furthermore, in one modified circuit breaker 100, a predetermined space S1 between the first fixed contact 11 and the first movable contact 31 when the movable contact 3 is in the open position is located on the extension of one of the flow paths 50 (left side in Figures 9 and 10). In other words, the extension of one of the flow paths 50 intersects with the line segment (referred to as the "first line segment") connecting the first movable contact 31 and the first fixed contact 11 of the moved movable contact 3. In particular, the extension of one of the flow paths 50 intersects with the first line segment near the first fixed contact 11. Also, a predetermined space S2 between the second fixed contact 21 and the second movable contact 32 when the movable contact 3 is in the open position is located on the extension of the other flow path 50 (right side in Figures 9 and 10). In other words, the extension of the other flow path 50 intersects the line segment (referred to as the "second line segment") connecting the second movable contact 32 and the second fixed contact 21 of the moved movable contact 3. In particular, the extension of the other flow path 50 intersects the second line segment near the second fixed contact 21. With this configuration, in one modified example of the circuit breaker 100, the gas introduced into the containment chamber 70 from each flow path 50 is directed toward predetermined spaces S1 and S2, which are the spaces between the contacts, and is blown directly onto the arc generated between the contacts (see arrow W2 in Figure 10). This makes it possible to cool the arc more effectively and further promote arc extinguishing. It also makes it possible to extend the arc more effectively and further promote arc extinguishing.

[0137] In the basic example and one modified example of the circuit breaker 100 of Embodiment 1, the flow path 50 is not limited to a columnar (tubular) shape formed in the side wall of the case 52. The flow path 50 may be, for example, a notch extending upward from the lower end of the side wall of the case 52.

[0138] In the basic example and one modified example of the circuit breaker 100 of Embodiment 1, the pyroactuator 5 is not limited to a configuration that moves the movable contact 3 via a piston 53. For example, the circuit breaker 100 of Embodiment 1 may be configured such that the movable contact 3 directly receives the pressure of the gas generated by the igniter 51 (the movable contact 3 constitutes part of the outer wall of the pressurizing chamber 520), and the movable contact 3 is moved directly by the gas pressure. In this case, the case 52 does not need to be provided with a flow path 50.

[0139] (2) Embodiment 2 The circuit breaker 100 of Embodiment 2 will be described with reference to Figures 11 and 12.

[0140] The circuit breaker 100 of Embodiment 2 differs from Embodiment 1 mainly in that the movement mechanism for moving the movable contact 3 from the closed position to the open position is equipped with a trip device 8. In the circuit breaker 100 of Embodiment 2, components similar to those in Embodiment 1 are denoted by the same reference numerals and their descriptions are omitted as appropriate.

[0141] (2.1) Configuration The circuit breaker 100 of this embodiment, like the first embodiment, includes a first fixed terminal 1, a second fixed terminal 2, a movable contact 3, a holding part 4 (a contact pressure spring 42 which is an elastic part), an igniter 51, a case 52, and a housing 7. However, in the circuit breaker 100 of this embodiment, the moving mechanism includes a trip device 8 instead of a pressurizing chamber 520 and a piston 53. The trip device 8 moves the movable contact 3 from the closed position to the open position in response to an abnormal current flowing through the circuit including the movable contact (first movable contact) 31 and the fixed contact (first fixed contact) 11.

[0142] As shown in Figure 11, the trip device 8 of this embodiment comprises an excitation coil 81, a movable element 82, a stator 83, and a cylindrical body 84. In the trip device 8 of this embodiment, the movable contact 3 is moved to the open position by the electromagnetic force generated by the magnetic flux produced in the excitation coil 81 when an abnormal current flows through the excitation coil 81.

[0143] The excitation coil 81 has its first end connected to the first fixed terminal 1. The second end of the excitation coil 81 is connected to the first end of an electrical circuit (a circuit constituting the power supply system 200) whose second end is connected to the second fixed terminal 2. In other words, the excitation coil 81 is connected in series with the series circuit of first fixed terminal 1 - movable contact 3 - second fixed terminal 2 between the first and second ends of the electrical circuit. Therefore, the current flowing through the movable contact 3 flows through the excitation coil 81, and the excitation coil 81 is excited by this current. As shown in Figure 11, the excitation coil 81 is wound around the lower part of the cylindrical body 84 and around the stator 83.

[0144] The cylindrical body 84 is made of a non-magnetic metal material. The cylindrical body 84 has a cylindrical portion and a bottom wall (lower wall) that closes the opening on one side (lower side) of the cylindrical portion. More specifically, the cylindrical body 84 is formed as a bottomed cylinder with an open top surface, consisting of a cylindrical portion and a circular bottom wall. A through hole is formed in the center of the bottom wall of the housing 7, and the upper end (periphery of the opening) of the cylindrical body 84 is fixed to the bottom wall of the housing 7 so as to cover the through hole in the bottom wall of the housing 7.

[0145] The movable element 82 is a cylindrical movable iron core. The movable element 82 is made of a magnetic material. The movable element 82 is housed within a cylindrical body 84. The movable element 82 is positioned within the cylindrical body 84 so as to be movable in the vertical direction. A contact pressure spring 42 (holding part 4) is positioned between the bottom wall (upper surface) of the cylindrical body 84 and the movable element 82 (lower surface) within the cylindrical body 84. A holding rib 841 is formed on the upper surface of the bottom wall of the cylindrical body 84, which is inserted into the lower end of the contact pressure spring 42. The movable element 82 is pushed upward by the contact pressure spring 42. The movable element 82 is movable between a first position (see Figure 11) where it is pushed upward by the contact pressure spring 42 to its highest position, and a second position (see Figure 12) where it is compressed by the contact pressure spring 42 to its lowest position. However, the movable element 82 is normally held in the first position by the spring force of the contact pressure spring 42. The movable element 82 is connected to the movable contact element 3 by a shaft 831 that passes through a through-hole in the bottom wall of the housing 7.

[0146] The shaft 831 is formed from a non-magnetic metal material into a long, cylindrical shape in the vertical direction. The upper end of the shaft 831 is connected to the central part of the movable contact 3. The lower end of the shaft 831 is connected to the movable element 82 through a through hole formed in the bottom wall of the housing 7. Therefore, when the movable element 82 moves vertically, its movement is transmitted to the movable contact 3 via the shaft 831, and the movable contact 3 moves vertically in accordance with the movement of the movable element 82.

[0147] As shown in Figure 11, when the movable element 82 is in the first position, the first movable contact 31 and the second movable contact 32 of the movable contact 3 are in contact with the first fixed contact 11 and the second fixed contact 21, respectively. In other words, when the movable element 82 is in the first position, the movable contact 3 is in the closed position. As shown in Figure 12, when the movable element 82 is in the second position, the first movable contact 31 and the second movable contact 32 of the movable contact 3 are away from the first fixed contact 11 and the second fixed contact 21, respectively. In other words, when the movable element 82 is in the second position, the movable contact 3 is in the open position (see Figure 12).

[0148] The stator 83 is a cylindrical fixed iron core. The stator 83 is made of a magnetic material. The stator 83 is fixed below the bottom wall of the cylindrical body 84.

[0149] In the trip device 8, the excitation coil 81, the movable element 82, and the stator 83 all have their central axes aligned on the same straight line in the vertical direction.

[0150] The trip device 8 moves the movable element 82 from the first position (the position shown in Figure 11) to the second position (the position shown in Figure 12) by the magnetic flux generated in the excitation coil 81 in response to an abnormal current exceeding a specified value flowing through the movable contact 3. At this time, the movable contact 3 is pulled by the shaft 831 and moves from the closed position to the open position.

[0151] In other words, the trip device 8 moves the movable element 82 to the second position by the magnetic flux generated in the excitation coil 81 in response to the abnormal current flowing through the movable contact 3, thereby forcibly separating the movable contact (first movable contact) 31 from the fixed contact (first fixed contact) 11. In this embodiment, the second movable contact 32 is also separated from the second fixed contact 21 at this time. Hereafter, the operation in which the trip device 8 forcibly separates the movable contact (first movable contact) 31 from the fixed contact (first fixed contact) 11 will be referred to as "tripping".

[0152] Here, the trip device 8 does not simply trip when current flows through the excitation coil 81, but only when the attractive force acting from the stator 83 to the movable element 82 exceeds the spring force of the contact spring 42. The attractive force acting from the stator 83 to the movable element 82 changes according to the magnitude of the current (load current) flowing through the excitation coil 81. The trip device 8 is configured such that when the current flowing through the excitation coil 81 becomes an abnormal current exceeding a specified value, the magnetic attractive force generated in the excitation coil 81 exceeds the spring force of the contact spring 42.

[0153] A magnet 9 is positioned between the stator 83 and the bottom wall of the cylindrical body 84. The magnet 9 is a permanent magnet and has a first and second pole surface with opposite polarities on both its upper and lower surfaces. The first pole surface (upper surface) of the magnet 9 is in contact with the bottom wall of the cylindrical body 84. The second pole surface (lower surface) of the magnet 9 is in contact with the stator 83. In other words, the magnet 9 is sandwiched between the stator 83 and the bottom wall of the cylindrical body 84. For example, the first pole surface is the north pole and the second pole surface is the south pole, but they may be reversed.

[0154] The magnet 9 holds the movable element 82 in the second position by the magnetic flux generated by the magnet 9 when the trip device 8 moves the movable element 82 to the second position. In other words, in this embodiment, after the trip device 8 moves the movable element 82 to the second position, the circuit breaker 100 holds the movable element 82 in the second position by the magnetic attraction force generated by the magnet 9. To put it another way, once the trip device 8 trips and the movable element 82 moves to the second position, the movable element 82 is held (latched) in the second position by the magnet 9.

[0155] In this embodiment, the magnet 9 is positioned such that when the trip device 8 moves the movable element 82 to the second position, the magnetic flux generated by the excitation coil 81 and the magnetic flux generated by the magnet 9 are in the same direction within the movable element 82. In other words, when the movable element 82 is in the second position, the magnetic flux generated by the excitation coil 81 and the magnetic flux generated by the magnet 9 pass through the movable element 82. In this embodiment, the magnetic polarity (i.e., the orientation of the magnetic pole surface) of the magnet 9 is set so that it generates a magnetic flux within the movable element 82 that is in the same direction as the magnetic flux generated by the excitation coil 81.

[0156] The circuit breaker 100 of this embodiment includes the igniter 51 and case 52 of the pyro actuator 5 in the basic example of Embodiment 1, but does not include the piston 53. Furthermore, the shape of the case 52 in the circuit breaker 100 of this embodiment differs from that of the basic example of Embodiment 1. Note that the igniter 51 in this embodiment is the same as that in the basic example of Embodiment 1, so its description is omitted.

[0157] The case 52 is made of metal, for example, aluminum or an aluminum alloy. The case 52 is formed in a bottomed cylindrical shape with an open top and a closed bottom.

[0158] An igniter 51 is fitted into the space in the upper part of case 52. The upper opening of case 52 (internal space) is closed by the igniter 51. Case 52 is attached to housing 7 so as to block the through hole 731 of lid member 73.

[0159] Two flow channels 50 connecting the inside and outside of the case 52 are formed on the right and left portions of the lower surface of the case 52. The first end 501 of each flow channel 50 is connected to the containment chamber 70, and the second end 502 is connected to the internal space of the case 52. In this embodiment, there is no airtight space inside the case 52. In this embodiment, the gas generated by the igniter 51 is introduced directly into the containment chamber 70 (through the internal space of the case 52 and the flow channels 50).

[0160] Each of the two flow paths 50 is cylindrical in shape with a constant diameter. One of the two flow paths 50 (the left flow path 50 in Figures 11 and 12) guides the gas generated by the igniter 51 so that it is blown into a predetermined space S1 (see Figure 12) between the first movable contact 31 and the first fixed contact 11. The other of the two flow paths 50 (the right flow path 50 in Figures 11 and 12) guides the gas generated by the igniter 51 so that it is blown into a predetermined space S2 (see Figure 12) between the second movable contact 32 and the second fixed contact 21. Each of the two flow paths 50 extends diagonally downward from the inside to the outside of the case 52.

[0161] (2.2) Operation Next, the operation of the circuit breaker 100 with the above configuration will be explained with reference to Figures 11 and 12.

[0162] In the circuit breaker 100 of this embodiment, the second end of the excitation coil 81 is connected to the first end of an electrical circuit (for example, a circuit constituting the power supply system 200), and the second electrode 22 is connected to the second end of the electrical circuit.

[0163] Under normal operation of the electrical circuit, the spring force of the contact spring 42 is greater than the attractive force acting from the stator 83 on the movable element 82. Therefore, the movable contact 3 is held in place mainly by this spring force, such that the first movable contact 31 is connected to the first fixed contact 11 and the second movable contact 32 is connected to the second fixed contact 21 (see Figure 11). In other words, under normal operation of the electrical circuit, the movable element 82 is in the first position, which is furthest from the stator 83. Also, under normal operation of the electrical circuit, the movable contact 3 is in the closed position, with the first movable contact 31 in contact with the first fixed contact 11 and the second movable contact 32 in contact with the second fixed contact 21. At this time, current flows from the first end of the electrical circuit towards the second end of the electrical circuit, passing through the excitation coil 81, the first fixed terminal 1, the movable contact 3, and the second fixed terminal 2 in that order.

[0164] On the other hand, if the current flowing through the electrical circuit (excitation coil 81) becomes an abnormal current exceeding a specified value (an electrical circuit malfunction), the attractive force acting from the stator 83 on the movable element 82 exceeds the spring force of the contact pressure spring 42. As a result, the trip device 8 trips, the movable element 82 moves to the second position, and the movable contact 3 moves to the open position. Consequently, the electrical circuit between the first fixed terminal 1 and the second fixed terminal 2 is interrupted, and the current flowing through the electrical circuit between the first fixed terminal 1 and the second fixed terminal 2 is interrupted.

[0165] Furthermore, if the current flowing through the electrical circuit (excitation coil 81) exceeds a specified value, the control circuit 207, for example, detects this abnormal current through the current sensor 206. Upon detecting an abnormal current, the control circuit 207 energizes the heating element 515 by passing current between the pair of pin electrodes 54 of the igniter 51. As a result, the gunpowder in the combustion section 513 burns, generating a large amount of gas. The pressure of the gas causes the low-strength portion of the lower wall of the metal sleeve 512 to rupture, and the gas is released into the internal space of the case 52 through the ruptured portion.

[0166] The gas generated by the igniter 51 is introduced into the containment chamber 70 through the flow path 50 of the case 52. The gas introduced into the containment chamber 70 is directed towards a predetermined space S1 between the first movable contact 31 and the first fixed contact 11, or a predetermined space S2 between the second movable contact 32 and the second fixed contact 21 (see arrow W3 in Figure 12).

[0167] In the circuit breaker 100 of this embodiment, the gas (electrically insulating gas) generated by the igniter 51 is introduced into the containment chamber 70, thereby increasing the pressure in the containment chamber 70. This cools the arc generated between the contacts, and the insulating properties of the arc discharge plasma or metal vapor are enhanced, thus promoting arc extinguishing.

[0168] Furthermore, the gas introduced into the containment chamber 70 from the flow path 50 is blown into a predetermined space S1 between the first movable contact 31 and the first fixed contact 11, or into a predetermined space S2 between the second movable contact 32 and the second fixed contact 21. This cools the arc generated between the contacts and promotes arc extinguishing.

[0169] Thus, in the circuit breaker 100 of this embodiment, the introduction of gas generated by the igniter 51 into the predetermined spaces S1 and S2 makes it possible to quickly extinguish the arc.

[0170] Note that the timing of the trip device 8 tripping and the timing of the ignition device 51 starting to release gas can be either earlier or later. The ignition device 51 may start releasing gas before the trip device 8 trips, or it may start releasing gas after the trip device 8 trips, or they may happen simultaneously. It is preferable that the ignition device 51 starts releasing gas after the trip device 8 trips.

[0171] (2.3) Variant The circuit breaker 100 of Modification 1 of Embodiment 2 will be described with reference to Figures 13 to 15. Figure 13 is a cross-sectional view of the main part of the circuit breaker 100 of Modification 1 before operation. Figure 14 is a side view of the main part of the circuit breaker 100 of Modification 1 before operation, viewed from a direction perpendicular to Figure 13 (right side). Figure 15 is a side view of the main part of the circuit breaker 100 of Modification 1 after operation, viewed from the same direction as Figure 14. Hereinafter, the circuit breaker 100 of Embodiment 2 will also be referred to as the circuit breaker 100 of the basic example of Embodiment 2.

[0172] As shown in Figures 13 and 14, the circuit breaker 100 of the modified example 1 is equipped with only one set of a movable contact 31 and a fixed contact 11 in the circuit connecting the first electrode 12 and the second electrode 22. Specifically, the first fixed terminal 1 is a plate-shaped member made of a conductive metal material. The first fixed terminal 1 has a first fixed contact 11 at one end (the left end in Figure 14) and the other end (the right end in Figure 14) functions as the first electrode 12. The second fixed terminal 2 is a plate-shaped member made of a conductive metal material that is shorter than the first fixed terminal 1 and is arranged to face the first fixed terminal 1 in the vertical direction. The second fixed terminal 2 has one end (the right end in Figure 14) that functions as the second electrode 22. The movable contact 3 has a movable contact 31 at one end (the left end in Figure 14) that is connected to the fixed contact 11. Furthermore, the movable contact 3 and the second fixed terminal 2 are not connected by a contact set consisting of a movable contact and a fixed contact, but by a braided wire 87 made of braided copper wire.

[0173] Furthermore, the case 52 housing the igniter 51 has only one flow path 50 in the center of its bottom wall. The case 52 is positioned such that the first end 501 of the flow path 50 faces a predetermined space S1 between the movable contact 31 and the fixed contact 11 (see Figure 15). As a result, gas is introduced from a direction perpendicular to the predetermined space S1.

[0174] Although not shown in the diagram, the circuit breaker 100 of the modified example 1, like the basic example of Embodiment 2, also includes a housing 7 that accommodates the first fixed contact 11, the movable contact 3, and the upper end of the shaft 831. The igniter 51 and case 52, the braided wire 87, and a portion of the second fixed terminal 2 (the leftmost portion) are also arranged inside the housing 7 (inside the housing chamber 70).

[0175] In this modified example, when an abnormal current flows through the electrical circuit, the excitation coil 81 is excited, causing the movable element 82 to move from the first position (the position shown in Figure 14) to the second position (the position shown in Figure 15). Consequently, the movable contact 3 moves from the open position (the position shown in Figure 14) to the open position (the position shown in Figure 15). Furthermore, the control circuit 207 supplies current to the igniter 51, generating gas from the igniter 51, which is then blown into the predetermined space S1 between the movable contact 31 and the fixed contact 11. This cools the arc generated between the contacts, enabling rapid arc extinguishing.

[0176] Furthermore, the circuit breaker 100 in this modified example may also include a magnet 9 that holds the movable element 82 in the second position, similar to the basic example in Embodiment 2.

[0177] A modified example of Embodiment 2, the circuit breaker 100, will be described with reference to Figures 16 and 17.

[0178] The circuit breaker 100 of this modified example differs from the circuit breaker 100 of the basic example of Embodiment 2 in that it is equipped with a permanent magnet 43 instead of a contact pressure spring 41 as the holding part 4. Other aspects are the same as the circuit breaker 100 of the basic example of Embodiment 2, so a detailed explanation is omitted.

[0179] In this modified circuit breaker 100, as shown in Figure 17, the movable contact 3 has a main body 33 and a pair of protrusions 34, and is formed in a cross shape when viewed from above. The main body 33 is long in the left-right direction and has a first movable contact 31 and a second movable contact 32 at both ends in the longitudinal direction. The pair of protrusions 34 protrude in the front-rear direction from the side surface of the main body 33. A permanent magnet 43 is provided on each of the protrusions 34 of the movable contact 3. As shown in Figure 16, the center of the movable contact 3 faces the bottom surface of the case 52. On the lower surface of the lid member 73 of the housing 7, a pair of magnetic members (not shown), specifically iron pieces, are provided at the front-rear positions of the case 52 (positions facing the permanent magnets 43).

[0180] In the modified example 2, the iron piece is attracted to the permanent magnet 43, and with the iron piece and the permanent magnet 43 separated, the first movable contact 31 and the second movable contact 32 are connected to the first fixed contact 11 and the second fixed contact 21 (see Figure 16).

[0181] In this modified example, when the trip device 8 trips, the movable element 82 moves from the first position (the position shown in Figure 16) to the second position against the magnetic attraction between the iron piece and the permanent magnet 43, and the movable contact 3 moves from the closed position (the position shown in Figure 16) to the open position. As a result, the electrical circuit between the first fixed terminal 1 and the second fixed terminal 2 is interrupted. At the same time, the control circuit 207 generates gas from the igniter 51 and introduces it into the containment chamber 70. This cools the arc generated between the contacts, making it possible to extinguish the arc quickly.

[0182] In this modified example, a magnetic member may be provided on the movable contact 3, and a permanent magnet 43 may be provided on the lid member 73 of the housing 7. A spacer may also be provided between the permanent magnet 43 and the magnetic member. The movable contact 3 may be maintained in a closed state with the permanent magnet 43 in direct contact with the magnetic member. Furthermore, the holding part 4 may include both a contact pressure spring 41 and a permanent magnet 43.

[0183] A circuit breaker 100 of the third modified example of Embodiment 2 will be described with reference to Figure 18.

[0184] The circuit breaker 100 of this modified example differs from the circuit breaker 100 of the basic example of Embodiment 2 mainly in that it includes a bimetallic plate 88 as the trip device 8, instead of the excitation coil 81, movable element 82, stator 83, and cylindrical body 84. Other aspects are the same as the circuit breaker 100 of the basic example of Embodiment 2, so a description will be omitted.

[0185] In this modified circuit breaker 100, as shown in Figure 18, the movable contact 3 is held in the closed position by a contact pressure spring 41, similar to the basic example of Embodiment 1. In addition, a bimetallic plate 88 is attached to the lower surfaces of the first fixed terminal 1 and the second fixed terminal 2 via a metal plate 89. The lower surface of the bimetallic plate 88 is in contact with the upper surface of the movable contact 3.

[0186] In this modified example, when an abnormal current flows through the movable contact 3, the bimetallic plate 88 bends downward (see the dotted line in Figure 18). As a result, the movable contact 3 moves from the closed position to the open position.

[0187] In other words, in this modified example, the circuit breaker 100 moves the movable contact 3 to the open position by bending the bimetal plate 88 when an abnormal current flows through the circuit including the movable contact (first movable contact) 31 and the fixed contact (first fixed contact) 11.

[0188] This makes it possible to interrupt the electrical circuit between the first fixed terminal 1 and the second fixed terminal 2.

[0189] In this modified example, a holding mechanism may be provided to hold the movable contact 3 in the open position after it has been moved to the open position by the bimetallic plate 88. The holding mechanism may be, for example, a combination of a permanent magnet and a magnetic member provided on the movable contact 3 and the inner wall of the housing 7. In addition, the trip device 8 may include the bimetallic plate 88 in addition to the excitation coil 81, movable element 82, stator 83, and cylindrical body 84.

[0190] The circuit breaker 100 of the basic example of Embodiment 2 and the modified examples 1 to 3 may also be equipped with yokes 61 and 62, similar to Embodiment 1.

[0191] (3) Other variations The application of the circuit breaker 100 is not limited to a fuse for the vehicle 300. The circuit breaker 100 may be used to interrupt any electrical circuit that may carry a large current, such as a short-circuit current. The circuit breaker 100 may also be a relay (electromagnetic relay) equipped with an electromagnet.

[0192] A guide may be formed within the housing chamber 70 of the housing 7 to guide the direction of movement of the movable contact 3. The guide is formed vertically and elongated on the inner wall of the housing chamber 70 so as to contact the side of the movable contact 3 along the direction of movement of the movable contact 3. This makes it less likely for the movable contact 3 to tilt when it is moved by the pyroactuator 5. The guide may also be a rod that extends upward from the bottom of the housing chamber 70 and passes through the movable contact 3.

[0193] The basic examples and modified configurations of Embodiments 1 and 2 can be combined as appropriate.

[0194] A specific example (Specific Example 1) of a circuit breaker 100, which is a modified example combining Embodiment 1 and Embodiment 2, will be described with reference to Figures 19 to 21. The circuit breaker 100 of this specific example functions as a so-called normally-on type (b-contact) device. The circuit breaker 100 comprises an excitation coil 81, an igniter 51, and a moving mechanism.

[0195] As shown in Figure 19, the housing 7 contains a fixed contact (first fixed contact) 11 of a fixed terminal 1 (first fixed terminal) 1, a second fixed contact 21 of a second fixed terminal 2, and a movable contact 3 having a movable contact (first movable contact) 31 and a second movable contact 32. The igniter 51 is positioned facing the upper surface of the movable contact 3. A through hole is formed in the bottom wall of the housing 7, and a cylindrical body 84 is fixed so as to cover the through hole in the bottom wall. A shaft 831, whose upper end is coupled to the movable contact 3, is positioned so that its lower end is exposed inside the cylindrical body 84 through the through hole in the bottom wall of the housing 7. A movable element 82 and a contact pressure spring 42 are arranged inside the cylindrical body 84. The movable element 82 is coupled to the lower end of the shaft 831. A stator 83 is fixed below the bottom wall of the cylindrical body 84. An excitation coil 81 is arranged to surround the movable element 82 and the stator 83.

[0196] The movable contact 3 is held in a closed position where the movable contact (first movable contact) 31 contacts the fixed contact (first fixed contact) 11 by the spring force from the contact pressure spring 42, etc. (see Figure 19).

[0197] The excitation coil 81 is controlled by the control circuit 200, which controls the energization of the excitation coil 81. When the excitation coil 81 is energized, the magnetic flux generated by the excitation coil 81 causes the movable element 82 to move downward. As the movable element 82 moves downward, the shaft 831 and the movable contact 3 also move downward together with the movable element 82, causing the movable contact 3 to move from the closed position (see Figure 19) to the first open position (see Figure 20). On the other hand, when the energization of the excitation coil 81 is stopped, the movable element 82 moves upward due to the spring force of the contact pressure spring 42, etc., and the movable contact 3 moves to the closed position (see Figure 19).

[0198] The moving mechanism includes the space connecting the igniter 51 and the movable contact 3 (the space between the igniter 51 and the movable contact 3). In other words, the circuit breaker 100 in this specific example is configured such that the movable contact 3 directly receives the pressure of the gas generated by the igniter 51 (the movable contact 3 constitutes part of the outer wall of the pressurizing chamber 520), and the movable contact 3 moves by directly receiving the gas pressure from the igniter 51. The moving mechanism moves the movable contact 3 from the closed position (see Figure 19) or the first open position (see Figure 20) to the second open position (see Figure 21), where the movable contact (first movable contact) 31 is further away from the fixed contact (first fixed contact) 11. The second open position here is the position of the movable contact 3 where the movable contact (first movable contact) 31 is further away from the fixed contact (first fixed contact) 11 than when the movable contact 3 is in the first open position. In other words, in this specific example, the distance between the closed position and the second open position is longer than the distance between the closed position and the first open position. When the movable contact 3 moves downward to the second open position, the movable element 82 also moves downward. The movable element 82 is held (latched) in the position shown in Figure 21 by the magnetic flux generated by the magnet 9.

[0199] A circuit breaker 100 of another specific example (Specific Example 2) of a modified example combining Embodiment 1 and Embodiment 2 will be described with reference to Figures 22 and 23. The circuit breaker 100 of this specific example functions as a so-called normally-off type (a-contact) device. The circuit breaker 100 is equipped with an excitation coil 81, an igniter 51, and a moving mechanism, similar to the circuit breaker 100 of Specific Example 1. The following description will focus on the differences from Specific Example 1.

[0200] In the circuit breaker 100 shown in Figure 22, the stator 83 is fixed to the bottom wall of the housing 7 inside the cylindrical body 84. The stator 83 has a through hole in the center that extends vertically. The lower end of the shaft 831 extends downward through the through hole in the bottom wall of the housing 7 and the through hole in the stator 83 and is fixed to the movable element 82. A return spring 85 is positioned between the movable element 82 and the stator 83. An excitation coil 81 is positioned to surround the movable element 82 and the stator 83.

[0201] The movable contact 3 is held in a first open position, where the movable contact (first movable contact) 31 is separated from the fixed contact (first fixed contact) 11, by the spring force that the movable element 82 receives from the return spring 85 (see Figure 22).

[0202] When the excitation coil 81 is energized, the magnetic flux generated by the excitation coil 81 causes the movable element 82 to move upward. As the movable element 82 moves upward, the shaft 831 and the movable contact 3 also move upward together with the movable element 82, causing the movable contact 3 to move from the first open position (see Figure 22) to the closed position (see Figure 23). On the other hand, when the energization of the excitation coil 81 is stopped, the spring force of the return spring 85 causes the movable element 82 to move downward, and the movable contact 3 moves to the first open position (see Figure 22). In other words, the circuit breaker 100 in this specific example functions as a contact device with a so-called normally open (a) contact.

[0203] The moving mechanism is the space connecting the igniter 51 and the movable contact 3 (the space between the igniter 51 and the movable contact 3). In other words, the movable contact 3 moves by directly receiving the gas pressure from the igniter 51. The moving mechanism moves the movable contact 3 to a second open position (see Figure 22) where the movable contact (first movable contact) 31 is separated from the fixed contact (first fixed contact) 11. Here, the second open position is the same as the first open position. That is, in this specific example, the distance between the closed position and the second open position is equal to the distance between the closed position and the first open position. When the movable contact 3 moves downward to the second open position, the movable element 82 also moves downward.

[0204] A further specific example (Specific Example 3) of the circuit breaker 100, which is a modified example combining Embodiment 1 and Embodiment 2, will be described with reference to Figures 24 and 25. The circuit breaker 100 of this specific example has a structure in which the pyro actuator 5 of the circuit breaker 100 of the basic example of Embodiment 2 (see Figure 11) is replaced with a pyro actuator 5 of a modified example of Embodiment 1 (a pyro actuator 5 equipped with a piston 53; see Figure 9).

[0205] In this specific example, the circuit breaker 100 can move the movable contact 3 to the open position by pushing the movable contact 3 with a piston 53 that is moved by the pressure in the pressurizing chamber 520 when gas is generated in the igniter 51. In addition, the circuit breaker 100 in this specific example can also move the movable contact 3 to the open position by the electromagnetic force generated by the magnetic flux produced by the excitation coil 81 when an abnormal current flows through the excitation coil 81 of the trip device 8. Figure 24 shows the circuit breaker 100 in this specific example, in a state where neither the igniter 51 nor the trip device 8 is operating. Figure 25 shows the circuit breaker 100 in this specific example, in a state where the piston 53 is pushed by the gas pressure from the igniter 51, and the movable contact 3 is moved to the open position by being pushed by this piston 53.

[0206] A further specific example (Specific Example 4) of the circuit breaker 100, which is a modified example combining Embodiment 1 and Embodiment 2, will be described with reference to Figures 26 to 28. The circuit breaker 100 of this specific example has a structure in which the pyro actuator 5 of the circuit breaker 100 of Specific Example 1 (see Figure 19) is replaced with the pyro actuator 5 of a modified example of Embodiment 1 (see Figure 9).

[0207] In the circuit breaker 100 of this specific example, the movable contact 3 moves between a closed position (see Figure 26) and a first open position (see Figure 27) in accordance with the switching on and off of the excitation coil 81. That is, when the excitation coil 81 is not energized, the movable contact 3 is held in a closed position, with the movable contact (first movable contact) 31 in contact with the fixed contact (first fixed contact) 11, by the spring force from the contact pressure spring 42, etc. When the excitation coil 81 is energized, the movable contact 3 is held in a first open position, with the movable contact (first movable contact) 31 away from the fixed contact (first fixed contact) 11, by the electromagnetic force from the magnetic flux generated by the excitation coil 81. Furthermore, when the pyro actuator 5 is driven and the igniter 51 generates gas, the piston 53 is pushed downward by the pressure in the pressurizing chamber 520, and the movable contact 3 moves to a second open position (see Figure 28) as it is pushed by the piston 53.

[0208] A further specific example (Specific Example 5) of the circuit breaker 100, which is a modified example combining Embodiment 1 and Embodiment 2, will be described with reference to Figures 29 to 31. The circuit breaker 100 of this specific example has a structure in which the pyro actuator 5 of the circuit breaker 100 of Specific Example 2 (see Figure 22) is replaced with the pyro actuator 5 of a modified example of Embodiment 1 (see Figure 9).

[0209] In the circuit breaker 100 of this specific example, the movable contact 3 moves between a closed position (see Figure 30) and a first open position (see Figure 29) in accordance with the switching on and off of the excitation coil 81. That is, when the excitation coil 81 is not energized, the movable contact 3 is held in a first open position, where the movable contact (first movable contact) 31 is away from the fixed contact (first fixed contact) 11, by the spring force from the return pressure spring 85, etc. When the excitation coil 81 is energized, the movable contact 3 is held in a closed position, where the movable contact (first movable contact) 31 is in contact with the fixed contact (first fixed contact) 11, by the electromagnetic force from the magnetic flux generated by the excitation coil 81. Furthermore, when the pyro actuator 5 is driven and the igniter 51 generates gas, the piston 53 is pushed downward by the pressure in the pressurizing chamber 520, and the movable contact 3 moves to a second open position (see Figure 31) by being pushed by the piston 53. Here, the second open position is the same as the first open position.

[0210] In the circuit breaker 100 of specific examples 1 to 5, the gas generated by the igniter 51 is introduced into the containment chamber 70 of the housing 7, thereby promoting arc extinguishing.

[0211] Furthermore, in specific examples 1, 2, 4, and 5, when the pyro actuator 5 is not driven, the circuit breaker 100 can be used as an electromagnetic relay equipped with a contact device.

[0212] Note that the relationship between the closed position, the first open position, and the second open position is not limited to the positional relationships shown in each of the specific examples above. That is, the distance between the closed position and the first open position may be longer, shorter, or equal to the distance between the closed position and the second open position. Preferably, the distance between the closed position and the second open position is longer than the distance between the closed position and the first open position.

[0213] Furthermore, the circuit breaker 100 in specific examples 3 to 5 may also include the pyro actuator 5 of the basic example in Embodiment 1.

[0214] Furthermore, in each of the above specific examples, the case 52 may also be provided with a second cylindrical portion (a portion having a frustoconical inner surface whose diameter decreases towards the bottom) and a third cylindrical portion (a portion having a cylindrical inner surface with a smaller diameter than the base 533 of the piston 53) as a stopper mechanism.

[0215] Furthermore, in each of the above specific examples, the circuit breaker 100 may also include a holder and a contact pressure spring. The holder is rectangular in shape with openings on both the left and right sides, and the movable contact 3 is passed through it in the left-right direction. The upper end of the shaft 831 is coupled to the lower wall of the holder. The contact pressure spring is positioned inside the holder between the upper surface of the lower wall of the holder and the lower surface of the movable contact 3, and biases the movable contact 3 upward. This configuration makes it possible to ensure contact pressure between the movable contact (first movable contact) 31 and the fixed contact (first fixed contact) 11, and between the second movable contact 32 and the second fixed contact 21, when the movable contact 3 is in the closed position.

[0216] (4) Aspect As is clear from the embodiments and modifications described above, the circuit breaker (100) of the first embodiment comprises a fixed terminal (1), a movable contact (3), a moving mechanism, an igniter (51), and a housing chamber (70). The fixed terminal (1) has a fixed contact (11). The movable contact (3) has a movable contact (31) connected to the fixed contact (11). The moving mechanism moves the movable contact (3) from a closed position to an open position. The closed position is the position of the movable contact (3) where the movable contact (31) is connected to the fixed contact (11). The open position is the position of the movable contact (3) where the movable contact (31) is separated from the fixed contact (11). The igniter (51) generates gas by combustion. The housing chamber (70) houses the fixed contact (11) and the movable contact (3). In the circuit breaker (100), gas is introduced into the containment chamber (70).

[0217] According to the first embodiment, the gas generated by the igniter (51) is introduced into the housing chamber (70) that houses the fixed contact (11) and the movable contact (3). Therefore, even if an arc occurs between the contacts, this gas makes it possible to quickly extinguish the arc.

[0218] In the second embodiment of the circuit breaker (100), the gas is introduced into a predetermined space (S1) between the fixed contact (11) and the movable contact (31) when the movable contact (3) is in the open position.

[0219] According to the second embodiment, the gas generated by the igniter (51) is introduced into a predetermined space (S1) between the movable contact (31) and the fixed contact (11) when the movable contact (3) is in the open position. Therefore, even if an arc occurs between the contacts, this gas makes it possible to quickly extinguish the arc.

[0220] The circuit breaker (100) of the third embodiment includes a flow path (50) for guiding gas so that the gas is blown into a predetermined space (S1).

[0221] According to the third embodiment, since the gas is blown onto the arc by the flow path (50), it is possible to accelerate the extinguishing of the arc.

[0222] In the fourth embodiment, the circuit breaker (100) is configured such that gas is introduced from a direction perpendicular to the predetermined space (S1) in the second or third embodiment.

[0223] According to the fourth embodiment, the arc generated in a predetermined space (S1) can be effectively deformed or stretched, thereby promoting arc extinguishing and improving the breaking performance.

[0224] The circuit breaker (100) of the fifth embodiment, in any of the first to fourth embodiments, comprises a pressurized chamber (520) and a piston (53) as the moving mechanism. The pressurized chamber (520) is subjected to gas pressure. The piston (53) is moved by the pressure in the pressurized chamber (520) and applies a force toward the open position to the movable contact (3) which is in the closed position, thereby moving the movable contact (3). In the circuit breaker (100), a portion of the gas is introduced from the pressurized chamber (520) into a predetermined space (S1).

[0225] According to the fifth embodiment, the movable contact (3) can be moved using the pressure (energy) of the gas, and by introducing the gas into a predetermined space (S1), it is possible to quickly extinguish the arc generated between the contacts.

[0226] The circuit breaker (100) of the sixth embodiment, in any of the first to fourth embodiments, includes a tripping device (8) in the moving mechanism. The tripping device (8) moves the movable contact (3) from the closed position to the open position in response to an abnormal current flowing through the circuit, which includes a movable contact (31) and a fixed contact (11).

[0227] According to the sixth embodiment, in a device (such as a relay) in which the circuit is interrupted by a trip device (8), it is possible to quickly extinguish the arc generated between the contacts.

[0228] In the seventh embodiment of the circuit breaker (100), in the sixth embodiment, the trip device (8) has an excitation coil (81) that constitutes part of the circuit. The trip device (8) moves the movable contact (3) to the open position by electromagnetic force generated by the magnetic flux generated in the excitation coil (81) when an abnormal current flows through the circuit.

[0229] According to the seventh embodiment, in a device in which an electrical circuit is interrupted by an electromagnetic force generated by the magnetic flux generated in the excitation coil (81), it is possible to quickly extinguish the arc generated between the contacts.

[0230] The circuit breaker (100) of the eighth embodiment, in the sixth or seventh embodiment, includes a trip device (8) which is a bimetallic plate (88) that bends when an abnormal current flows through the circuit. The trip device (8) moves the movable contact (3) to the open position by bending the bimetallic plate (88) when an abnormal current flows through the circuit.

[0231] According to the eighth aspect, in a device in which the electrical circuit is interrupted by the curvature of a bimetallic plate (88), it is possible to quickly extinguish the arc generated between the contacts.

[0232] The circuit breaker (100) of the ninth embodiment includes an elastic part (contact pressure springs 41, 42) that applies an elastic force to the movable contact (3) in the direction toward the closed position, in any of the first to eighth embodiments.

[0233] According to the ninth aspect, the movable contact (3) can be held in the closed position.

[0234] The circuit breaker (100) of the tenth embodiment includes a permanent magnet (43) for holding the movable contact (3) in a closed position, in any of the first to ninth embodiments.

[0235] According to the tenth embodiment, the movable contact (3) can be held in the closed position.

[0236] The circuit breaker (100) of the eleventh embodiment includes a gas-sealing space, including a containment chamber (70), in any of the first to tenth embodiments.

[0237] According to the eleventh embodiment, the pressure in the space containing the gas increases when the gas is introduced into the space that seals the gas. This makes it possible to quickly extinguish the arc generated between the contacts.

[0238] The circuit breaker (100) of the twelfth embodiment comprises a fixed terminal (1), a movable contact (3), an excitation coil (81), and a moving mechanism. The fixed terminal (1) has a fixed contact (11). The movable contact (3) has a movable contact (31) connected to the fixed contact (11). The igniter (51) generates gas by combustion. The excitation coil (81) moves the movable contact (3) from a closed position where the movable contact (31) is connected to the fixed contact (11) to a first open position where the movable contact (31) is separated from the fixed contact (11). The moving mechanism moves the movable contact (3) to a second open position where the movable contact (31) is separated from the fixed contact (11).

[0239] The configurations of the embodiments described in parts 2 to 11 are not essential components of the circuit breaker (100) and can be omitted as appropriate. [Explanation of Symbols]

[0240] 100 Circuit interrupter 1 1st fixed terminal (fixed terminal) 11 1st fixed contact (fixed contact) 3. Movable contact 31 1st movable contact (movable contact) 41. Contact spring (elastic part) 42. Contact spring (elastic part) 43 Permanent Magnets 50 flow channels 51 Igniter 520 Pressurized Chamber 53 Pistons 70 Confinement Rooms 8. Trip device 81 Excitation coil 88 Bimetallic Sheets S1 Predetermined space

Claims

1. A first fixed terminal including a first fixed contact, A second fixed terminal, including a second fixed contact located to the right of the first fixed contact, A movable contact includes a first end portion having a first movable contact located below the first fixed contact, a second end portion having a second movable contact located below the second fixed contact, and an intermediate portion connecting the first end portion and the second end portion. A pyroactuator having a piston provided above the intermediate portion and an igniter containing gunpowder, which moves the piston toward the movable contact by the combustion of the gunpowder, A housing that accommodates the first fixed contact, the second fixed contact, and the movable contact, A coil positioned on the outside of the housing, A movable element that moves upward or downward when the coil is energized, A shaft positioned below the aforementioned intermediate section, which moves upward when the movable element moves upward and downward when the movable element moves downward, Equipped with, The movable contact is, As the shaft moves upward or downward, it moves between a closed position in which the first fixed contact and the first movable contact are in contact and the second fixed contact and the second movable contact are in contact, and a first open position in which the first movable contact is away from the first fixed contact and the second movable contact is away from the second fixed contact. When the gunpowder in the igniter burns, the piston moving toward the movable contact moves to a second open position located below the first open position. The pressure in the housing when the gunpowder in the igniter is burning and the first movable contact is separated from the first fixed contact and the second movable contact is separated from the second fixed contact is greater than the pressure in the housing when the movable contact is in the closed position and the gunpowder in the igniter is not burning. Electromagnetic relay.

2. In a top view, the piston is positioned to overlap with the shaft. The electromagnetic relay according to claim 1.

3. A holder connected to the shaft, A contact pressure spring is positioned between the holder and the movable contact, and biases the movable contact upward when it is in the closed position. Furthermore, The electromagnetic relay according to claim 2.

4. The housing has a through hole in the upper wall located above the first fixed contact and the second fixed contact, in which the pyro actuator is positioned. The upper end of the pyro actuator is located above the through hole, and the lower end of the pyro actuator is located below the through hole. The electromagnetic relay according to claim 1.

5. The pyroactuator burns the gunpowder in the igniter when the movable contact is in the closed position, and moves the movable contact from the closed position to the second open position. The electromagnetic relay according to claim 1.

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