Gas circuit breaker

Abstract

To provide a gas circuit breaker capable of maintaining an effective arc suppression of an arc for a long time even if it is used for a certain time.SOLUTION: A gas circuit breaker 10 is constructed so that a recessed strip part 25x of an insertion hole 25a of a nozzle 25 and a projecting part 12x of a fixed contact point 12a are fitted to each other at a relative position where the insertion hole 25a of the nozzle 25 in a step of a current interruption is nearly blocked in the fixed contact point 12a. That is, in the circumferential direction of the insertion hole 25a of the nozzle 25, since the projecting part 12x of the fixed contact point 12a remains while a side wall part between the recessed strip parts 25x of the insertion hole 25a is damaged in priority, an expansion of a gap between the nozzle 25 and the fixed contact point 12a in the insertion hole 25a is minimized.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a gas circuit breaker.

Background Art

[0002] In a gas circuit breaker that interrupts the current of a power system, it is desirable to quickly extinguish the arc that may occur between the fixed contact and the movable contact during the interruption operation. A gas circuit breaker called a puffer type strongly blows the insulating gas filled in its own puffer chamber toward the arc by the guidance of a nozzle during the interruption operation to actively extinguish the arc (see, for example, Patent Document 1). To improve the arc extinguishing performance of the gas circuit breaker, one means is to increase the pressure of the gas blown toward the location where the arc may occur.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a configuration where a nozzle is provided around the movable contact, the fixed contact is inserted inside the nozzle. Since the nozzle and the fixed contact operate relatively, it is necessary to set a gap in the direction orthogonal to the operating direction, that is, between the inner peripheral surface of the nozzle and the outer peripheral surface of the fixed contact. The gap between the nozzle and the fixed contact is also a leakage path for the gas blown from the puffer chamber toward the arc. In order to blow a higher-pressure gas toward the arc, it is desired to set the gap between the nozzle and the fixed contact to be as small as possible.

[0005] However, since the arc is generated near the nozzle, the inner peripheral surface of the nozzle is gradually worn out by the heat of the arc or the like. That is, since the inner diameter of the inner peripheral surface of the nozzle expands, the gap between the inner peripheral surface of the nozzle and the outer peripheral surface of the fixed contact also gradually widens. Then, since the amount of gas leaking from the gap between the nozzle and the fixed contact increases, the pressure of the gas blown against the arc gradually decreases. This hinders maintaining good arc extinction performance.

Means for Solving the Problem

[0006] A gas circuit breaker according to an aspect of the present disclosure includes a fixed contact and a movable contact disposed in an atmosphere of an insulating gas. When the poles are opened, the movable contact moves away from the fixed contact, and in order to extinguish the arc generated between the contacts and cut off the current, a buffer unit that performs a buffer operation of ejecting the insulating gas filled in the buffer chamber of the gas circuit breaker as arc extinguishing gas for the arc, and a cylindrical shape having an insertion hole provided so as to operate integrally with the movable contact and into which the fixed contact relatively inserts and withdraws. During the process of current interruption, while suppressing leakage of the insulating gas through the insertion hole in a manner of substantially closing the insertion hole in cooperation with the fixed contact, a nozzle having a rectifying function that makes the flow of the insulating gas directed toward the arc suitable, and is a gas circuit breaker comprising: a plurality of convex portions are provided on the outer peripheral surface of the fixed contact, and a plurality of concave portions into which the plurality of convex portions of the fixed contact respectively enter are provided on the inner peripheral surface of the insertion hole of the nozzle. The concave portions and the convex portions are configured to fit together at a relative position where the insertion hole of the nozzle is substantially closed by the fixed contact while allowing a relative insertion and withdrawal operation of the fixed contact with respect to the insertion hole of the nozzle.

[0007] According to the above configuration, in the process of current interruption of the gas circuit breaker, while allowing the relative insertion and extraction operation of the fixed contact with respect to the insertion hole of the nozzle, the plurality of concave portions of the insertion hole of the nozzle and the plurality of convex portions of the fixed contact are in a state of fitting together at the relative positions where the insertion hole of the nozzle is substantially blocked by the fixed contact. Generally, a nozzle made of insulating resin is more likely to be worn by an arc generated during current interruption compared to a fixed contact made of conductive metal, and the inner peripheral surface of the insertion hole of the nozzle is also more likely to be worn than the fixed contact. At this time, in the circumferential direction of the insertion hole of the nozzle, the side wall portion between the adjacent concave portions provided on itself is preferentially worn, while the convex portions of the fixed contact remain scattered. That is, even if the wear of the nozzle progresses, the expansion of the gap between the nozzle and the fixed contact in the insertion hole is suppressed as much as possible. Thereby, the leakage of the insulating gas from the insertion hole when the insertion hole of the nozzle is substantially blocked by the fixed contact can be suppressed as much as possible, and it becomes possible to maintain the effective arc extinction for a long time.

Effect of the Invention

[0008] According to the gas circuit breaker of the present disclosure, even when the use progresses, the effective arc extinction can be maintained for a long time.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0010] Hereinafter, an embodiment of the gas circuit breaker will be described. (Overall configuration of circuit breaker 10) As shown in FIG. 1, the circuit breaker 10 of the present embodiment is housed in a housing tank (not shown) filled with an insulating gas G and is arranged in the atmosphere of the insulating gas G. As the insulating gas G, CO2 gas (carbon dioxide gas), SF6 gas (sulfur hexafluoride gas), etc. are used.

[0011] The circuit breaker 10 includes a main contact portion 11 and an arc contact portion 12. The main contact portion 11 includes a fixed main contact 11a and a movable main contact 11b made of conductive metal, respectively. The arc contact portion 12 includes a fixed contact 12a and a movable contact 12b made of conductive metal, respectively. The fixed main contact 11a and the fixed contact 12a are configured as a fixed electrode portion (not shown) connected to one side of the electric circuit in which the circuit breaker 10 is installed. The movable main contact 11b and the movable contact 12b are configured as a movable electrode portion (not shown) connected to the other side of the electric circuit in which the circuit breaker 10 is installed. The movable main contact 11b and the movable contact 12b move forward and backward along the axial direction L1 (hereinafter simply referred to as the axial direction) with respect to the fixed main contact 11a and the fixed contact 12a. The opening and closing of the target electric circuit of the circuit breaker 10 is performed by the contact and separation operation of the movable main contact 11b and the movable contact 12b with respect to the fixed main contact 11a and the fixed contact 12a by moving forward and backward.

[0012] FIG. 1 shows the closed state of the circuit breaker 10 in which the fixed main contact 11a and the fixed contact 12a and the movable main contact 11b and the movable contact 12b are in contact with each other. FIG. 2 shows an intermediate state of the breaking operation toward the open state of the circuit breaker 10 in which the fixed main contact 11a and the fixed contact 12a and the movable main contact 11b and the movable contact 12b are separated from each other.

[0013] (Main contact portion 11) As shown in Fig. 1, the main contact portion 11 is composed of a fixed main contact 11a and a movable main contact 11b. The fixed main contact 11a has a substantially cylindrical shape. The fixed main contact 11a is fixedly provided such that its axis is along the axial direction. The movable main contact 11b has a substantially cylindrical shape with a slightly smaller diameter than the fixed main contact 11a. The movable main contact 11b is arranged coaxially with the fixed main contact 11a and performs a reciprocating motion along the axial direction with respect to the fixed main contact 11a. Inside the fixed main contact 11a in the radial direction, the fixed contact 12a of the arc contact portion 12 is arranged. Also, inside the fixed main contact 11a in the radial direction, it is possible for a nozzle 25 (described later) that protrudes from the tip portions of the movable main contact 11b and the movable contact 12b to enter. Inside the movable main contact 11b in the radial direction, the movable contact 12b of the arc contact portion 12 is arranged.

[0014] (Arc contact portion 12) As shown in Fig. 1, the arc contact portion 12 is composed of a fixed contact 12a and a movable contact 12b. The fixed contact 12a has a substantially cylindrical rod shape. The fixed contact 12a is fixedly provided such that its axis is along the axial direction. The movable contact 12b has a substantially cylindrical shape with a slightly larger diameter than the fixed contact 12a. The movable contact 12b is arranged coaxially with the fixed contact 12a and performs a reciprocating motion along the axial direction with respect to the fixed contact 12a.

[0015] The fixed contact 12a is electrically connected to the fixed main contact 11a of the main contact portion 11 and forms an integral structure as a fixed electrode portion. The movable contact 12b is electrically connected to the movable main contact 11b of the main contact portion 11 and forms an integral structure as a movable electrode portion. The movable main contact 11b and the movable contact 12b are configured such that their tip portions contact each other or separate from each other by the reciprocating motion with respect to the fixed main contact 11a and the fixed contact 12a. The movable main contact 11b and the movable contact 12b move in conjunction with an operating rod (not shown) connected to them.

[0016] As shown in FIGS. 1 and 3, the fixed contact 12a of the present embodiment has a protruding portion 12x on the outer peripheral surface of the main body near its tip. A plurality of, for example, 18 protruding portions 12x are provided, and they are provided at equal intervals in the circumferential direction of the outer peripheral surface of the main body of the fixed contact 12a. The plurality of protruding portions 12x have the same shape as each other. The protruding portion 12x has a rectangular cross-sectional shape in the radial direction of the fixed contact 12a and extends radially. Between adjacent protruding portions 12x, that is, the concave portion 12y, has a concave shape when viewed from the protruding portion 12x and has a trapezoidal cross-section. The protruding portion 12x extends linearly in the axial direction from the outer peripheral surface of the main body at the same height. The protruding portion 12x is provided at a position corresponding to the nozzle 25 described later in the contact state between the fixed contact 12a and the movable contact 12b. The axial length of the protruding portion 12x is set to a predetermined dimension smaller than the length in the same direction of the narrow portion 25c of the nozzle 25. The protruding portion 12x may be integrally formed with the main body of the fixed contact 12a, or may be formed separately from the main body and joined to each other. The above-described shape, number, manufacturing mode, etc. of the protruding portion 12x are examples.

[0017] When the gas circuit breaker 10 is in the closed pole state, the fixed main contact 11a and the movable main contact 11b of the main contact portion 11 are in contact with each other. Also, the fixed contact 12a and the movable contact 12b of the arc contact portion 12 are in contact with each other. That is, the gas circuit breaker 10 makes the target circuit in a conductive state. On the other hand, when it becomes necessary to interrupt the current in the target circuit of the gas circuit breaker 10, the movable main contact 11b instantaneously separates from the fixed main contact 11a of the main contact portion 11, and the movable contact 12b instantaneously separates from the fixed contact 12a of the arc contact portion 12. At that time, the timing of the separation of the movable contact 12b from the fixed contact 12a of the arc contact portion 12 is set to be later than the timing of the separation of the movable main contact 11b from the fixed main contact 11a of the main contact portion 11. That is, it is configured such that an arc A (see FIG. 2) can occur between the fixed contact 12a and the movable contact 12b of the arc contact portion 12.

[0018] (Buffer mechanism 20) The gas circuit breaker 10 of this embodiment includes a buffer mechanism 20. The buffer mechanism 20 combines a mechanical buffer type and a thermal buffer type. The buffer mechanism 20 has a function of spraying an insulating gas G as an arc extinguishing gas between the tip portions of the fixed contact 12a and the movable contact 12b of the arc contact portion 12 where an arc A can occur. The buffer mechanism 20 is provided integrally with the movable main contact 11b and the movable contact 12b.

[0019] The buffer mechanism 20 includes a cylinder 21 and a piston 22. The cylinder 21 has a peripheral wall portion 23a of the movable main contact 11b and a peripheral wall portion 23b of the movable contact 12b that are spaced apart from each other in the radial direction, and a substantially annular plate-shaped end wall portion 23c that closes the space between the portions near the tip ends of the peripheral wall portions 23a and 23b. The end wall portion 23c is integrally provided on the peripheral wall portion 23a of the movable main contact 11b, for example. An opening 23x is provided in the radially inner portion of the end wall portion 23c. A plurality of openings 23x are provided at intervals in the circumferential direction. The cylinder 21 is integrally configured with the movable main contact 11b and the movable contact 12b, and operates integrally with the movable main contact 11b and the movable contact 12b.

[0020] The piston 22 is arranged in the cylinder 21 in such a manner that it is inserted therein. The piston 22 is provided immovably. The piston 22 is provided so as to be relatively movable with respect to the cylinder 21 which operates integrally with the movable main contact 11b and the movable contact 12b. The piston 22 partitions the internal space of the cylinder 21 as a buffer chamber 24 in a predetermined space, and varies the volume of the buffer chamber 24 by relative movement with the cylinder 21. Among such relative movements, the retreating movement of the movable contact 12b away from the fixed contact 12a, that is, the relative movement of the cylinder 21 in the case where an arc A can occur between the two contacts 12a and 12b, is the relative pushing-in movement of the piston 22 with respect to the cylinder 21. The buffer chamber 24 communicates with an opening 23x provided in the end wall portion 23c of the cylinder 21. An insulating gas G is introduced into the buffer chamber 24 from the opening 23x. Further, the insulating gas G filled in the buffer chamber 24 is ejected as an arc extinguishing gas from the opening 23x toward the location where the arc A can occur by a mechanical buffer operation and a thermal buffer operation described later.

[0021] (Nozzle 25) The buffer mechanism 20 is provided with a nozzle 25 attached thereto. The nozzle 25 is attached, for example, to the end wall portion 23c of the cylinder 21. The nozzle 25 operates integrally with the movable main contact 11b and the movable contact 12b, like the cylinder 21. The nozzle 25 has a rectifying function that makes the flow of the insulating gas G suitable according to the relative position between the movable contact 12b that moves and the fixed contact 12a that does not move.

[0022] The nozzle 25 is made of, for example, an insulating resin. The nozzle 25 has a substantially cylindrical shape and is provided coaxially with the movable contact 12b such that its own axis is along the axial direction. The inner part of the cylindrical nozzle 25 is an insertion hole 25a that penetrates in the axial direction. The tip portion of the fixed contact 12a relatively inserts and withdraws into the insertion hole 25a as the movable contact 12b operates. On the inner peripheral portion of the insertion hole 25a of the nozzle 25, a guide portion 25b, a narrow portion 25c, and an expanding portion 25d are provided in order from the axial base end of the end wall portion 23c of the cylinder 21 toward the tip. The guide portion 25b, the narrow portion 25c, and the expanding portion 25d are respectively provided at positions that are approximately trisected in the axial direction.

[0023] The guide portion 25b cooperates with the outer peripheral surface of the movable contact 12b to form a guide flow path 26. The guide flow path 26 is a flow path that turns from the opening 23x of the end wall portion 23c of the cylinder 21 to the further front side of the tip portion of the movable contact 12b. That is, at the tip portion of the movable contact 12b, it is a location where an arc A can occur when separated from the fixed contact 12a, and the guide flow path 26 has a function of guiding the insulating gas G ejected from the opening 23x of the buffer chamber 24 toward the arc A. The narrow portion 25c is the portion that is closest to the fixed contact 12a in the radial direction during the relative insertion and withdrawal operation. When the relatively inserting and withdrawing fixed contact 12a is at the axial position where it is inserted into its narrow portion 25c, the narrow portion 25c makes the insertion hole 25a of the nozzle 25 in a substantially closed state with the fixed contact 12a. The narrow portion 25c has a function of suppressing the leakage of the insulating gas G toward the tip portion of the nozzle 25 through the insertion hole 25a. The expanding portion 25d is configured to expand toward the tip portion of the nozzle 25. When the fixed contact 12a is at the axial position where it has come out of the narrow portion 25c, the expanding portion 25d has a function of weakening and discharging the momentum of the insulating gas G flowing at high speed toward the tip portion of the nozzle 25 through the insertion hole 25a.

[0024] As shown in FIGS. 1 and 3, a plurality of concave grooves 25x into which a plurality of protruding portions 12x provided on the fixed contact 12a that relatively moves in an insertion and extraction manner enter are provided in the width narrowing portion 25c of the insertion hole 25a of the nozzle 25 of the present embodiment. For example, 18 concave grooves 25x are provided corresponding to the protruding portions 12x, and they are provided at equal intervals in the circumferential direction of the inner peripheral surface of the width narrowing portion 25c. The plurality of concave grooves 25x have the same shape as each other. The concave grooves 25x each have a rectangular cross-sectional shape in the radial direction of the nozzle 25 and extend radially in the radial direction. The side wall portions 25y between adjacent concave grooves 25x have a trapezoidal cross-sectional shape. It can also be said that the side wall portions 25y have a convex shape when viewed from the concave grooves 25x. The concave grooves 25x are set to a size having a slight gap with respect to the protruding portions 12x. The concave grooves 25x each extend linearly in the axial direction with the same depth. The concave grooves 25x allow the movement of the protruding portions 12x of the fixed contact 12a that relatively moves in an insertion and extraction manner. The concave grooves 25x are open in the axial direction in the expansion portion 25d and are closed without opening in the axial direction in the guide portion 25b. The concave grooves 25x may be integrally formed in the width narrowing portion 25c of the nozzle 25. The above-described shape, number, production mode, etc. of the concave grooves 25x are examples. The nozzle 25 has a function of rectifying the insulating gas G ejected from the opening 23x of the buffer chamber 24 described above. Details of the operations of the buffer mechanism 20 and the nozzle 25 will be described later.

[0025] (Operation of the Present Embodiment) The operation of the present embodiment will be described. As shown in FIG. 1, in the closed pole state of the gas circuit breaker 10, the movable main contact 11b of the main contact portion 11 and the fixed main contact 11a are in contact, and the movable contact 12b of the arc contact portion 12 and the fixed contact 12a are in contact. When it becomes necessary to open the pole in the gas circuit breaker 10, the gas circuit breaker 10 performs a current interruption operation of instantaneously retracting and separating the movable main contact 11b and the movable contact 12b from the fixed main contact 11a and the fixed contact 12a via the operating rod.

[0026] As shown in Fig. 2, at the initial stage of the interruption operation of the gas circuit breaker 10, following the separation of the movable main contact 11b of the main contact portion 11 from the fixed main contact 11a, the movable contact 12b of the arc contact portion 12 begins to separate from the fixed contact 12a. Then, an arc A may be generated between the tip of the movable contact 12b, which is the arc contact portion 12, and the tip of the fixed contact 12a. In conjunction with the retraction operations of the movable main contact 11b and the movable contact 12b, the buffer mechanism 20 performs an arc extinguishing operation on the arc A.

[0027] In the buffer mechanism 20, a relative pushing operation of the piston 22 into the cylinder 21 is performed in conjunction with the retraction operation of the movable contact 12b. In the buffer chamber 24, the insulating gas G inside the chamber is compressed by the operation of the piston 22. The compressed insulating gas G jets out from the opening 23x communicating with the buffer chamber 24. The insulating gas G jetted out from the opening 23x is directed along the guide flow path 26 of the nozzle 25 toward the location where the arc A may be generated, and is forcefully blown against the arc A as an arc extinguishing gas. The arc extinguishing operation of the arc A based on the pushing of the piston 22 is a mechanical buffer operation, and is the main arc extinguishing operation in the case of a small current region where the heat generation amount of the arc A is relatively low.

[0028] When the interruption current increases, the heat generated from the arc A that may be generated between the movable contact 12b and the fixed contact 12a also becomes hotter. When the arc A becomes hot, the thermal expansion of the insulating gas G around the arc A also becomes greater. At the initial stage of the interruption operation shown in Fig. 2, in the positional relationship between the nozzle 25 that operates together with the movable contact 12b and the fixed contact 12a, the guide flow path 26 of the nozzle 25 opens, and the insertion hole 25a is substantially blocked by the fixed contact 12a at the narrow portion 25c. Since the opening of the guide flow path 26 on the tip side of the movable contact 12b, that is, the guide flow path 26 near the generated arc A, opens, the main flow of the insulating gas G expanded by the heat of the arc A flows from the guide flow path 26 into the buffer chamber 24 through the opening 23x. As a result, the internal pressure of the buffer chamber 24 greatly increases.

[0029] When the operation of the movable contact 12b further progresses from the initial stage of the interruption operation shown in Fig. 2, in the positional relationship between the nozzle 25 that moves together with the movable contact 12b and the fixed contact 12a, the fixed contact 12a relatively comes out from the narrow portion 25c of the insertion hole 25a of the nozzle 25. Since the insertion hole 25a of the nozzle 25 changes from the closed state to the open state, the insulating gas G filled at high pressure in the buffer chamber 24 changes to a flow that gushes out vigorously from the opening 23x. The insulating gas G ejected from the opening 23x is guided along the guide flow path 26 of the nozzle 25 and directed toward the arc A, and is strongly blown onto the arc A as an arc extinguishing gas. The arc extinguishing operation of the arc A based on the thermal expansion of the insulating gas G due to the heat of the arc A is a thermal buffer operation, and is the main arc extinguishing operation in the case of a large current region where the heat generation amount of the arc A is relatively high. In the buffer mechanism 20, the mechanical buffer operation and the thermal buffer operation are performed in parallel, and either one of the buffer operations becomes effective depending on the strength of the arc A generated by the current interruption.

[0030] (Regarding the wear of the nozzle 25) The nozzle 25 functions to substantially close the insertion hole 25a in cooperation with the fixed contact 12a at the narrow portion 25c of the insertion hole 25a at the initial stage of the interruption operation. The nozzle 25 including such a function is subject to wear due to the arc A generated when the current of the gas circuit breaker 10 is interrupted. In particular, the wear on the inner peripheral surface of the insertion hole 25a of the nozzle 25 close to the arc A tends to be large.

[0031] In the initial stage of use of the nozzle 25, since the wear of the insertion hole 25a of the nozzle 25, particularly the wear of the narrow portion 25c, has not progressed, as shown in Fig. 3, the convex portion 12x of the fixed contact 12a is inserted into the concave groove portion 25x provided on itself. That is, the gap between the insertion hole 25a of the nozzle 25 including the concave groove portion 25x and the fixed contact 12a including the convex portion 12x is small, and the insertion hole 25a of the nozzle 25 is well closed by the fixed contact 12a. Therefore, when the insulating gas G is blown onto the arc A generated at the tip of the movable contact 12b through the guide flow path 26 of the nozzle 25, the leakage of the insulating gas G from the insertion hole 25a to the tip side of the nozzle 25 is suppressed to a small value, and the arc extinction of the arc A is effectively performed.

[0032] As the use of the gas circuit breaker 10 progresses and the opportunity for current interruption increases, the wear of the resin nozzle 25 preferentially proceeds among the members close to the arc A. In the process of wear progressing at the narrow portion 25c in the insertion hole 25a of the nozzle 25, the side wall portion 25y, which is relatively convex compared to the concave groove portion 25x where the arc A is difficult to reach and is greatly affected by the arc A, preferentially wears. The side wall portion 25y gradually wears toward the bottom of the concave groove portion 25x, that is, toward the outer side in the radial direction of the nozzle 25, and the height of the side wall portion 25y gradually decreases. FIGS. 4 and 5 show a state where the wear has proceeded until the side wall portion 25y reaches the same height as the bottom of the concave groove portion 25x.

[0033] Although not shown, the fixed contact of a conventional general configuration has a circumferential surface shape without unevenness on its outer circumferential surface, and correspondingly, the inner circumferential surface of the insertion hole of the nozzle also has a circumferential surface shape without unevenness. That is, in the process of wear progressing at the narrow portion in the insertion hole of the nozzle, the inner circumferential surface of the insertion hole wears substantially uniformly in the circumferential direction. Therefore, when the inner circumferential surface of the insertion hole experiences wear corresponding to the side wall portion 25y described above, in the conventional configuration, there is a concern that the radial gap expands over the entire circumferential direction of the insertion hole, increasing the leakage of the insulating gas.

[0034] In contrast, in the present embodiment, as shown in the radial cross-section of the nozzle 25 in FIG. 5, even if wear corresponding to the side wall portion 25y occurs, there is a mode in which the protruding portion 12x of the fixed contact 12a, which has a sufficiently smaller wear degree than the nozzle 25, exists. That is, the radial gaps between the insertion hole 25a of the nozzle 25 and the fixed contact 12a are scattered in the circumferential direction, and the expansion of the gaps can be suppressed to about half that of the conventional configuration. Therefore, the leakage of the insulating gas G can be suppressed as much as possible, and even as the use of the gas circuit breaker 10 progresses, it is possible to maintain the effective arc extinction of the arc A for a long time. This contributes to the improvement of the current interruption performance of the gas circuit breaker 10 of the present embodiment.

[0035] (Effect of the present embodiment) The effect of the present embodiment will be described. (1) When the gas circuit breaker 10 is in a relative position where the insertion hole 25a of the nozzle 25 is substantially closed by the fixed contact 12a during the current interruption process, the concave groove portion 25x of the insertion hole 25a of the nozzle 25 and the protruding portion 12x of the fixed contact 12a are fitted together. The nozzle 25 made of insulating resin is more likely to be worn by the arc A generated during current interruption compared to the fixed contact 12a made of conductive metal, and the inner peripheral surface of the insertion hole 25a of the nozzle 25 also wears more than the fixed contact 12a. At this time, in the circumferential direction of the insertion hole 25a of the nozzle 25, the side wall portion 25y between the adjacent concave groove portions 25x provided on itself is preferentially worn, while the protruding portions 12x of the fixed contact 12a remain scattered. That is, even if the wear of the nozzle 25 progresses, the expansion of the gap between the nozzle 25 and the fixed contact 12a in the insertion hole 25a can be suppressed as much as possible. Thereby, the leakage of the insulating gas G from the insertion hole 25a when the insertion hole 25a of the nozzle 25 is substantially closed by the fixed contact 12a can be suppressed as much as possible, and the effective arc extinction of the arc A can be maintained for a long time.

[0036] (2) The protruding portion 12x provided on the fixed contact 12a and the concave groove portion 25x provided on the nozzle 25 are arranged such that those having the same shape are provided at equal intervals in the circumferential direction. Therefore, the protruding portion 12x and the concave groove portion 25x can be easily manufactured respectively.

[0037] (3) The protruding portion 12x provided on the fixed contact 12a and the concave groove portion 25x provided on the nozzle 25 are each in a rectangular cross-sectional shape. Also in this case, the manufacturing of the protruding portion 12x and the concave groove portion 25x can be facilitated respectively.

[0038] (4) The concave groove portion 25x of the nozzle 25 extends continuously in the direction in which the fixed contact 12a relatively moves in the insertion and extraction operation, and has a concave shape with the front end in the insertion direction closed and the rear end in the insertion direction open. Also in this case, the leakage of the insulating gas G from the insertion hole 25a when the insertion hole 25a of the nozzle 25 is substantially closed by the fixed contact 12a can be suppressed as much as possible.

[0039] (Modified Example) This embodiment can be implemented with the following modifications. This embodiment and the following modification examples can be implemented in combination with each other within a technically non - conflicting range.

[0040] · Regarding the protruding portion 12x as a convex portion provided on the fixed contact 12a and the concave groove portion 25x as a concave portion provided on the nozzle 25, the above - described shape, arrangement, number, manufacturing method, etc. are merely examples and may be appropriately changed.

[0041] · Regarding the concave groove portion 25x of the nozzle 25, it has a concave shape in which the front end in the insertion direction where the fixed contact 12a relatively inserts and removes is closed and the rear end in the insertion direction is open. However, for example, it may be appropriately changed such as opening both ends.

[0042] · As the buffer portion, the buffer mechanism 20 that combines the mechanical buffer operation having the cylinder 21 and the piston 22 and the thermal buffer operation is used. However, it may also be one that only performs the thermal buffer operation without the piston 22.

[0043] · It includes two fixed main contacts 11a and fixed contacts 12a with divided functions such as the main contact portion and the arc contact portion, and two movable main contacts 11b and movable contacts 12b. It may also be provided with one fixed contact and one movable contact that combines the functions of the main contact portion and the arc contact portion into one.

[0044] · The fixed main contact 11a and the fixed contact 12a are set as immovable, but those that move slightly are also included. · In addition to the above, the configuration of the gas circuit breaker 10 may be appropriately changed.

Explanation of Reference Numerals

[0045] 10…Gas circuit breaker 11a…Fixed main contact (fixed contact) 11b…Movable main contact (movable contact) 12a…Fixed contact 12b…Movable contact 12x…Protruding portion (convex portion) 20…Buffer mechanism (buffer portion) 21…Cylinder 22…Piston 24…Buffer chamber 25…Nozzle 25a…Insertion hole 25x…Grooved portion (recess) L1…Axis A…Arc G…Insulating gas

Claims

1. A fixed contact and a movable contact are arranged in an insulating gas atmosphere. When the circuit is opened, the movable contact moves away from the fixed contact, and an arc generated between the contacts is extinguished to cut off the current. A puffer unit that performs a puffer operation of ejecting the insulating gas filled in the puffer chamber of the gas circuit breaker as the arc extinguishing gas. A cylindrical shape having an insertion hole through which the fixed contact relatively inserts and withdraws, provided so as to operate integrally with the movable contact. In the process of current interruption, in a mode of substantially closing the insertion hole in cooperation with the fixed contact, while suppressing leakage of the insulating gas through the insertion hole, a nozzle having a rectifying function that makes the flow of the insulating gas directed toward the arc suitable. A gas circuit breaker comprising: A plurality of convex portions are provided on the outer peripheral surface of the fixed contact, and a plurality of concave portions into which the plurality of convex portions of the fixed contact respectively enter are provided on the inner peripheral surface of the insertion hole of the nozzle. While allowing relative insertion and withdrawal of the fixed contact with respect to the insertion hole of the nozzle, the concave portions and the convex portions are configured to fit together at a relative position where the insertion hole of the nozzle is substantially closed by the fixed contact. Gas circuit breaker.

2. The plurality of convex portions of the fixed contact and the plurality of concave portions of the nozzle are provided at equal intervals in the circumferential direction with the same shape as each other. The gas circuit breaker according to claim 1.

3. The plurality of convex portions of the fixed contact and the plurality of concave portions of the nozzle have a rectangular cross section. The gas circuit breaker according to claim 1.

4. The plurality of concave portions of the nozzle continuously extend in the direction in which the fixed contact relatively inserts and withdraws, and have a concave shape in which the front end in the insertion direction is closed and the rear end in the insertion direction is open. The gas circuit breaker according to claim 1.

5. The puffer unit is configured as a combined type that performs a thermal puffer operation of ejecting the insulating gas filled in the puffer chamber at high pressure based on thermal expansion of the insulating gas by the arc, and a mechanical puffer operation of ejecting the insulating gas filled in the puffer chamber based on the pushing operation of the piston. The gas circuit breaker according to claim 1.

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