Current Interrupting Unit and Its Assembly Method

Abstract

To provide a current interruption part in which an interruption performance is improved.SOLUTION: A case 6 is constructed by: a first division case 7 which is detachably divided in a width direction, and having a side wall and peripheral walls 7b to 7e stood from an edge part of the side wall, and a second division case having the side wall and each peripheral wall stood from the edge part of the side wall. In the first division case, a first concave part 14a in which a first movable contact point 21a can be moved is formed in the peripheral wall 7b on an extension line of a movement path R1 of the first movable contact point, and a second concave part 14b in which a second movable contact point 21b can be moved is formed in the peripheral wall 7d on the extension line of a movement path R2 of the second movable contact point. Then, a power source side arc-extinguishing part 12 is arranged along the movement path of the first movable contact point of the first division case, and a load side arc-extinguishing part 13 is arranged along the movement path of the second movable contact point of the first division case.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a two-point cut-off type current interruption part arranged corresponding to each phase of a main circuit inside a circuit breaker and a method for assembling the current interruption part.

Background Art

[0002] As a two-point cut-off type current interruption part arranged inside a circuit breaker, for example, the current interruption part described in Patent Document 1 is known.

[0003] The current interruption part of Patent Document 1 has a case, a power source side fixed contact and a load side fixed contact, a movable contact provided with a first movable contact that contacts and separates from the fixed contact of the power source side fixed contact and a second movable contact that contacts and separates from the fixed contact of the load side fixed contact at both ends, a movable holder that rotates the movable contact, and a pair of arc extinguishing devices housed therein.

[0004] The case of the current interruption part is composed of a pair of split cases that can be split in the width direction, and each of the pair of split cases is a member in which a peripheral wall having a predetermined height is formed on the entire circumference of the side wall.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] When assembling the current interruption part of Patent Document 1, an operation of housing the power source side fixed contact, the load side fixed contact, the movable contact, the movable holder, and the pair of arc extinguishing devices is performed in one of the pair of split cases. During this housing operation, it is necessary to provide an incorporation space for incorporating the first and second movable contacts of the movable contact inside one of the split cases. However, if an embedding space is provided inside the split case, the arc extinguishing device can only be arranged along a part of the moving paths of the first and second movable contacts, and there is a risk that the breaking performance will deteriorate.

[0007] The present invention provides a current interrupting section capable of improving the breaking performance by arranging a pair of arc extinguishing devices along the moving paths of the first and second movable contacts of a movable contact, and an assembling method of a current interrupting section capable of assembling the current interrupting section without providing an embedding space for the movable contact inside the case.

Means for Solving the Problems

[0008] To achieve the above object, a current interrupting section according to an aspect of the present invention includes, in a case, a power supply side fixed contact having a power supply side fixed contact point, a load side fixed contact having a load side fixed contact point, a movable contact having first and second movable contact points that make contact with and separate from the power supply side fixed contact point and the load side fixed contact point at both ends, a movable contact holder that rotates the movable contact, a power supply side arc extinguishing section that extinguishes an arc generated between the power supply side fixed contact point and the first movable contact point, and a load side arc extinguishing section that extinguishes an arc generated between the load side fixed contact point and the second movable contact point, and is a two-point cut-off type current interrupting section in which these are housed. The case includes side walls facing each other and a peripheral wall rising from the edge of the side wall, and is composed of a first split case and a second split case that are detachably divided in the width direction. Further, in the first split case, a first concave portion in which the first movable contact point can move is formed on the peripheral wall on the extension line of the moving path of the first movable contact point, and a second concave portion in which the second movable contact point can move is formed on the peripheral wall on the extension line of the moving path of the second movable contact point. The power supply side arc extinguishing section is arranged over the entire moving path of the first movable contact point, and the load side arc extinguishing section is arranged over the entire moving path of the second movable contact point.

[0009] Moreover, the method for assembling the current interruption part according to one aspect of the present invention includes: a first assembling step of incorporating a power supply side fixed contact and a load side fixed contact into a first divided case; a second assembling step of incorporating a movable contact and a mover holder into the first divided case and holding the mover holder so that the first movable contact moves to the first concave portion and the second movable contact moves to the second concave portion; a third assembling step of incorporating a power supply side arc extinguishing part and a load side arc extinguishing part into the first divided case; a fourth assembling step of rotating the mover holder to move the first movable contact and the second movable contact inside the first divided case; and a fifth assembling step of abutting and fixing the peripheral wall of the first divided case and the peripheral wall of the second divided case.

Effects of the Invention

[0010] According to the current interruption part of the present invention, the interruption performance can be improved by arranging a pair of arc extinguishing devices along the movement paths of the first and second movable contacts of the movable contact. Moreover, according to the method for assembling the current interruption part of the present invention, the current interruption part can be assembled without providing an incorporation space for the movable contact inside the case, so that a pair of arc extinguishing devices can be arranged over the entire movement paths of the first and second movable contacts of the movable contact.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

[0012] Next, embodiments according to the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thicknesses of the respective layers, etc. are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Also, it goes without saying that there are portions where the dimensional relationships and ratios are different between the drawings.

[0013] Also, the embodiments shown below exemplify devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention does not specify the material, shape, structure, arrangement, etc. of the components as follows. The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims.

[0014] Note that terms indicating directions such as "longitudinal direction", "short dimension direction", "width direction", etc. described in the following description are used with reference to the directions of the attached drawings.

[0015] [Circuit Breaker] FIG. 1 shows a circuit breaker 1 according to an embodiment of the present invention, which includes an opening / closing handle 2, a toggle-type opening / closing mechanism 3, an overcurrent tripping device 4, and a current interrupting section 5. The current interrupting section 5 is provided corresponding to each phase of the main circuit. The circuit breaker 1 opens and closes the current interrupting section 5 of each phase via the opening / closing mechanism 3 by the ON / OFF operation of the opening / closing handle 2.

[0016] [Current Interrupting Section] FIGS. 2 to 8 show the detailed structure of the two-point cut-off type current interrupting section 5. FIG. 2 shows an interrupting section case 6 which is the housing of the current interrupting section 5. The interrupting section case 6 is composed of a first divided case 7 and a second divided case 8 that can be divided in the width direction. Also, as shown in FIG. 3, inside the interrupting section case 6, a power supply side fixed contact 9, a load side fixed contact 10, a mover unit 11, a power supply side arc extinguishing section 12, and a load side arc extinguishing section 13 are housed.

[0017] As shown in FIG. 4, the first divided case 7 constituting the interrupting section case 6 includes a side wall 7a and peripheral walls 7b to 7e that rise in a direction orthogonal to the edge of the side wall 7a. A concave portion 14a that is recessed inward in the width direction is formed in a part of the longitudinal direction of the peripheral wall 7b, and a concave portion 14b that is recessed inward in the width direction is also formed in a part of the longitudinal direction of the peripheral wall 7d. Arc-shaped guide walls 15a and 15b for guiding the rotation of a mover holder 20 described later are formed inside the side wall 7a surrounded by the peripheral walls 7b to 7e. A pair of elliptical through holes 16a and 16b through which a connecting shaft described later is inserted are formed in the side wall 7a.

[0018] The second divided case 8 is a member formed substantially symmetrically in the width direction with respect to the first divided case 7. As shown in FIG. 5, it includes side walls 8a and peripheral walls 8b to 8e that rise in a direction orthogonal to the edge of the side wall 8a. Inside the side wall 8a surrounded by the peripheral walls 8b to 8e, arc-shaped guide walls 17a and 17b for guiding the rotation of the mover holder 20 are formed. In the side wall 8a, a pair of elliptical through-holes 18a and 18b through which a connecting shaft is inserted are formed. Further, a convex portion 19a protruding outward in the width direction is formed in a part of the longitudinal direction of the peripheral wall 8b of the second divided case 8, and a convex portion 19b protruding outward in the width direction is also formed in a part of the longitudinal direction of the peripheral wall 13d located at the lower part in the height direction.

[0019] Then, by butting and arranging the peripheral walls 7b to 7e of the first divided case 7 and the peripheral walls 8b to 8e of the second divided case 8, as shown in FIG. 2, the convex portion 19a formed on the peripheral wall 8b of the second divided case 8 fits into the concave portion 14a formed on the peripheral wall 7b of the first divided case 7. Although not shown, with the convex portion 19b formed on the peripheral wall 8d of the second divided case 8 fitting into the concave portion 14b formed on the peripheral wall 7d of the first divided case 7, the first divided case 7 and the second divided case 8 are integrated to form the cutoff portion case 6.

[0020] As shown in FIG. 3, the power supply side fixed contact 9 is arranged on one side in the longitudinal direction of the cutoff portion case 6 and is a strip-shaped conductor that bends in a crank shape and extends from one side in the longitudinal direction to the other side. A power supply side terminal (not shown) is connected to one end 9a of the power supply side fixed contact 9 protruding outside the cutoff portion case 6, and a fixed contact point 9b is provided at the other end of the power supply side fixed contact 9.

[0021] As shown in FIG. 3, the load side fixed contact 10 is arranged on the other side in the longitudinal direction of the cutoff portion case 6 and is a flat strip-shaped conductor extending in the longitudinal direction. A fixed contact point 10a is provided on the inner side of the cutoff portion case 6 of the load side fixed contact 10, and a load side terminal (not shown) is connected to an end portion 10b located on the outer side of the cutoff portion case 6 of the load side fixed contact 10.

[0022] As shown in Fig. 3, the mover unit 11 includes a mover holder 20 rotatably supported by the interruption part case 6, and a rod-shaped conductor supported by the mover holder 20. The mover unit 11 is provided at both ends with a first movable contact 21a and a second movable contact 21b that make contact with and separate from the fixed contact 9b of the power supply side fixed contact 9 and the fixed contact 10a of the load side fixed contact 10.

[0023] The mover holder 20 is a substantially cylindrical insulating member with closed axial end openings. The outer periphery thereof is slidably supported by the guide walls 15a, 15b, 17a, 17b of the first divided case 7 and the second divided case 8 so as to be rotatable. The movable contact 21 is inserted and supported in the diameter direction of the mover holder 20. Inside the mover holder 20, biasing springs 20a, 20b for biasing the movable contact 21 counterclockwise in Fig. 3 are arranged.

[0024] Through holes 22a, 22b are formed in the mover holder 20, and the aforementioned connecting shafts are inserted through these through holes 22a, 22b and the through holes 16a, 16b and 18a, 18b formed in the interruption part case 6. The connecting shafts are also inserted through the mover holders 20 of the current interruption parts 5 of other phases, and the opening pole operations of the current interruption parts 5 of each phase are interlocked via the connecting shafts by the trip operation of the opening / closing mechanism 3.

[0025] As shown in Fig. 6, the power supply side arc extinguishing part 12 includes a plurality of arc extinguishing grids 23 arranged in layers, and a pair of arc extinguishing members 24a, 24b integrally arranged on the arc extinguishing grids 23.

[0026] The plurality of arc extinguishing grids 23 are formed in a thin flat plate shape and are magnetic bodies in which a pair of grid arms 23b and 23c extend parallel from the grid body 23a. The grid bodies 23a of these plurality of arc extinguishing grids 23, which are arranged at a predetermined interval in the plane normal direction, are sandwiched and supported by a pair of support plates 25, 25. The pair of arc extinguishing members 24a and 24b are high molecular materials having a substantially rectangular parallelepiped shape in which ablation gas is generated by melting at the time of arc generation. A plurality of arm insertion holes 24a1 and 24b1 are formed in the pair of arc extinguishing members 24a and 24b at a predetermined interval in the longitudinal direction.

[0027] Then, one grid arm 23b of the plurality of arc extinguishing grids 23 is inserted into the plurality of arm insertion holes 24a1 of one arc extinguishing member 24a, and the other grid arm 23c of the plurality of arc extinguishing grids 23 is inserted into the plurality of arm insertion holes 24b1 of the other arc extinguishing member 24b, whereby the pair of arc extinguishing members 24a and 24b are integrally arranged on the plurality of arc extinguishing grids 23 to constitute the power supply side arc extinguishing portion 12.

[0028] As shown in FIG. 3, the power supply side arc extinguishing portion 12 having the above configuration is arranged on the side of the first movable contact 21a of the movable contact 21. As shown in FIG. 7, a pair of grid arms 23b and 23c of the plurality of arc extinguishing grids 23 constituting the power supply side arc extinguishing portion 12 are arranged so as to sandwich the movement path R1 of the first movable contact 21a from the width direction. Then, the pair of arc extinguishing members 24a and 24b into which the pair of grid arms 23b and 23c are inserted also sandwich the movement path R1 of the first movable contact 21a from the width direction. Then, as shown in FIG. 3, the pair of arc extinguishing members 24a and 24b are continuously arranged from around the fixed contact 9b of the power supply side fixed contact 9 to the position where they contact the peripheral wall 7b (and the peripheral wall 8b) of the blocking portion case 6.

[0029] The load-side arc extinguishing portion 13 also has substantially the same structure as the power-source-side arc extinguishing portion 12, and as shown in FIG. 3, it is disposed on the side of the second movable contact 21b of the movable contact 21. As shown in FIG. 8, the pair of grid arms 23b and 23c and the pair of arc extinguishing members 24a and 24b of the load-side arc extinguishing portion 13 are arranged so as to sandwich the movement path R2 of the second movable contact 21b from the width direction, and are continuously arranged from around the fixed contact 10a of the load-side fixed contact 10 to the position where they contact the peripheral wall 7d (and the peripheral wall 8d) of the blocking portion case 6 (see FIG. 3).

[0030] [Operation of Current Interrupting Portion] Next, the operation of the current interrupting portion 5 of the present embodiment will be described with reference to FIG. 3. When an overcurrent flows during energization of the main circuit and the overload release device 4 of the circuit breaker 1 operates, the movable holder 20 of the movable unit 11 constituting the current interrupting portion 5 rotates clockwise by the trip operation of the opening / closing mechanism 3. Due to the rotation of the movable holder 20, the first movable contact 21a of the movable contact 21 separates from the fixed contact 9b of the power-source-side fixed contact 9 to become an open-pole state, and the second movable contact 21b separates from the fixed contact 10a of the load-side fixed contact 10 to become an open-pole state. Then, arcs are generated between the first movable contact 21a and the fixed contact 9b and between the second movable contact 21b and the fixed contact 10a.

[0031] The pair of arc extinguishing members 24a and 24b of the power supply side arc extinguishing portion 12 are arranged to sandwich the first movable contact 21a from the width direction and are arranged over the entire movement path R1 of the first movable contact 21a. For this reason, in the movement path R1 of the first movable contact 21a, when the pair of arc extinguishing members 24a and 24b are melted by the heat of the arc generated between the fixed contact 9b and the first movable contact 21a to generate ablation gas, the arc sprayed with the ablation gas is cooled, the arc voltage is increased, and the current peak is suppressed. The pair of arc extinguishing members 24a and 24b protect the pair of grid arm portions 23b and 23c of the power supply side arc extinguishing portion 12 from heating due to arc heat, and insulate the grid arm portions 23b and 23c, so that the arc extends toward the grid body 23a side and arc extinction is achieved. Further, since the pair of grid arm portions 23b and 23c are arranged to sandwich the movement path R1 of the first movable contact 21a from the width direction, early opening of the first movable contact 21a from the fixed contact 9b due to an increase in electromagnetic repulsive force and an increase in the arc driving force can increase the arc elongation amount.

[0032] Also, the pair of arc extinguishing members 24a and 24b of the load side arc extinguishing portion 13 are arranged to sandwich the second movable contact 21b from the width direction and are arranged over the entire movement path R2 of the second movable contact 21b. For this reason, in the movement path R2 of the second movable contact 21b, when the pair of arc extinguishing members 24a and 24b are melted by the heat of the arc generated between the fixed contact 10a and the second movable contact 21b to generate ablation gas, the arc is cooled by the ablation gas, the arc voltage is increased, and the current peak is suppressed. The pair of arc extinguishing members 24a and 24b protect the pair of grid arm portions 23b and 23c of the load side arc extinguishing portion 13 from heating due to arc heat, and insulate the grid arm portions 23b and 23c, so that the arc extends toward the grid body 23a side and arc extinction is achieved. Further, since the pair of grid arm portions 23b and 23c are arranged to sandwich the movement path R2 of the second movable contact 21b from the width direction, early opening of the second movable contact 21b from the fixed contact 101a due to an increase in electromagnetic repulsive force and an increase in the arc driving force can increase the arc elongation amount.

[0033] [Assembly method of current interruption portion] Next, a method for assembling the current interrupting unit 5 of the present embodiment will be described with reference to FIGS. 2, 3, 9(a) to (c), and 10(a) and (b). First, as shown in FIG. 9(a), the power supply side fixed contact 9 is arranged on the side of the peripheral walls 7c and 7d of the first divided case 7, and the load side fixed contact 10 is arranged on the side of the peripheral walls 7b and 7e.

[0034] Next, as shown in FIG. 9(b), the mover unit 11 is arranged in the first divided case 7. That is, the mover holder 20 is rotated in the clockwise direction A, and the first movable contact 21a is retracted from the inside of the first divided case 7 to be located in the concave portion 14a of the peripheral wall 7b, and the second movable contact 21b is retracted from the inside of the first divided case 7 to be located in the concave portion 14b of the peripheral wall 7d, and the mover holder 20 is held in this state.

[0035] Next, as shown in FIG. 9(c), the power supply side arc extinguishing portion 12 is arranged in the space from the fixed contact 9b of the power supply side fixed contact 9 inside the first divided case 7 to the peripheral wall 7b, and the load side arc extinguishing portion 13 is arranged in the space from the fixed contact 10a of the load side fixed contact 10 to the peripheral wall 7d. Note that the mover unit 11 may be arranged after arranging the power supply side arc extinguishing portion 12 and the load side arc extinguishing portion 13.

[0036] When the power supply side arc extinguishing portion 12 is arranged inside the first divided case 7, as shown in FIG. 10(a), the first movable contact 21a retracted in the concave portion 14a of the peripheral wall 7b is arranged on the extension line of the movement path R1 (see FIG. 3) between the pair of arc extinguishing members 24a and 24b of the power supply side arc extinguishing portion 12. Further, when the load side arc extinguishing portion 13 is arranged inside the first divided case 7, as shown in FIG. 10(b), the second movable contact 21b retracted in the concave portion 14b of the peripheral wall 7d is arranged on the extension line of the movement path R2 (see FIG. 3) between the pair of arc extinguishing members 24a and 24b of the load side arc extinguishing portion 13.

[0037] Next, rotate the mover holder 20 counterclockwise to move the first movable contact 21a that had been retracted into the concave portion 14a of the peripheral wall 7b onto the movement path R1 within the first divided case 7, and move the second movable contact 21b that had been retracted into the concave portion 14b of the peripheral wall 7d onto the movement path R1 within the first divided case 7.

[0038] Then, as shown in FIG. 2, abut the peripheral walls 8b to 8e of the second divided case 8 against the peripheral walls 7b to 7e of the first divided case 7, fit the convex portion 19a of the second divided case 8 into the concave portion 14a of the first divided case 7, and fit the convex portion 19b of the second divided case 8 into the concave portion 14b of the first divided case 7. Then, by integrally fixing the first divided case 7 and the second divided case 8, the assembly of the current interruption portion 5 is completed.

[0039] [Effect of Current Interruption Portion] Next, the effect of the current interruption portion 5 of the present embodiment will be described. First, when assembling the current interruption portion 5 of the present embodiment, by retracting the first and second movable contacts 21a and 21b of the movable contact 21 disposed in the first divided case 7 into the concave portion 14a of the peripheral wall 7b and the concave portion 14b of the peripheral wall 7d, there is no need to provide an incorporation space for the movable contact inside the first divided case 7. Therefore, since the power source side arc extinguishing portion 12 and the load side arc extinguishing portion 13 can be disposed on the movement paths R1 and R2 of the first and second movable contacts 21a and 21b, the interruption performance can be improved.

[0040] In addition, in the power supply side arc extinguishing portion 12, a pair of grid arm portions 23b and 23c of a plurality of arc extinguishing grids 23 arranged in layers sandwich the first movable contact 21a from the width direction and are arranged over the entire area of the movement path R1 of the first movable contact 21a. Further, a pair of arc extinguishing members 24a and 24b that generate ablation gas sandwich the first movable contact 21a from the width direction so as to surround the pair of grid arm portions 23b and 23c of the plurality of arc extinguishing grids 23. Similarly, in the load side arc extinguishing portion 13, a pair of grid arm portions 23b and 23c of the arc extinguishing grid 23 are arranged over the entire area of the movement path R2 of the second movable contact 21b while sandwiching the second movable contact 21b from the width direction, and a pair of arc extinguishing members 24a and 24b sandwich the second movable contact 21b from the width direction and are arranged.

[0041] Due to such a structure, in the movement paths R1 and R2 of the first and second movable contacts 21a and 21b, the arc generated between the fixed contact 9b and the first movable contact 21a and the arc generated between the fixed contact 10a and the second movable contact 21b are subjected to the blowing of ablation gas due to the melting of the pair of arc extinguishing members 24a and 24b, so that the arc voltage is increased and the current peak is suppressed. At the same time, the pair of arc extinguishing members 24a and 24b protect the pair of grid arm portions 23b and 23c of the power supply side arc extinguishing portion 12 and the load side arc extinguishing portion 13 from heating by the arc heat, and insulate the grid arm portions 23b and 23c, so that the arc extends toward the grid body 23a side to extinguish the arc, thereby improving the interruption performance. Further, since the pair of grid arm portions 23b and 23c sandwich the movement path R2 of the first movable contact 21a and the second movable contact 21b from the width direction, the early opening of the first movable contact 21a and the second movable contact 21b due to the increase in the electromagnetic repulsive force and the increase in the arc elongation amount due to the increase in the arc driving force can be achieved.

[0042] In addition, since the pair of arc extinguishing members 24a and 24b constituting the power source side arc extinguishing portion 12 and the load side arc extinguishing portion 13 are arranged so as to surround the pair of grid arm portions 23b and 23c, the gap dimensions (T1 and T2 shown in FIGS. 7 and 8) between the pair of arc extinguishing members 24a and 24b can be set small, whereby the amount of ablation gas generated by the pair of arc extinguishing members 24a and 24b can be increased. Further, by setting the gap dimensions T1 and T2 between the pair of arc extinguishing members 24a and 24b small, the plate width and plate thickness of the grid arm portions 23b and 23c inserted into the pair of arc extinguishing members 24a and 24b can be sufficiently secured, and further increase in electromagnetic repulsive force and arc driving force can be achieved.

[0043] [Comparative Example] FIG. 11 shows the current interruption portion 30 of the comparative example. The concave portions shown in the present embodiment are not formed on the peripheral walls 31b and 31d of the first divided case 31 constituting the current interruption portion 30 of the comparative example. For this reason, since the first movable contact 21a and the second movable contact 21b cannot be retracted from the inside of the first divided case 31, in addition to the space for arranging the power source side arc extinguishing portion 32 and the load side arc extinguishing portion 33, it is necessary to provide incorporation spaces S1 and S2 on the first movable contact 21a side and the second movable contact 21b side of the mover unit 11. Thus, by providing the incorporation spaces S1 and S2 inside the first divided case 31, the power source side arc extinguishing portion 32 and the load side arc extinguishing portion 33 cannot be provided with grid arm portions 23b and 23c on all the arc extinguishing grids 23, and ablation gas generating arc extinguishing members 32a and 33a can be provided only on a part of the movement paths of the first movable contact 21a and the second movable contact 21b. Therefore, the current interruption portion 30 of the comparative example may have a reduced interruption performance.

Explanation of Reference Numerals

[0044] 1 Circuit breaker 2 Opening / closing handle 3 Opening / closing mechanism 4 Overcurrent tripping device 5 Current interruption portion 6 Interruption portion case (case) 7 First divided case 7a Side wall 7b - 7e Peripheral wall 8 Second dividing case 8a Side wall 8b - 8e Peripheral wall 9 Power - side fixed contact 9b Fixed contact point (power - side fixed contact point) 10 Load - side fixed contact 10a Fixed contact point (load - side fixed contact point) 11 Movable unit 12 Power - side arc - extinguishing part 13 Load - side arc - extinguishing part 14a Concave part (first concave part) 14b Concave part (second concave part) 15a, 15b Guide wall 16a, 16b Through - hole 17a, 17b Guide wall 18a, 18b Through - hole 19a, 19b Convex part 20 Movable holder 20a, 20b Biasing spring 21 Movable contact 21a First movable contact point 21b Second movable contact point 22a, 22b Through - hole 23 Arc - extinguishing grid 23a Grid body 23b, 23c Grid arm part 24a, 24b Arc - extinguishing member 24a1, 24b1 Arm insertion hole 25 Support plate R1 Movement path of the first movable contact point R2 Movement path of the second movable contact point

Claims

1. In a two-point cut-off type current interruption section housed in a case and including a power supply side fixed contact having a power supply side fixed contact point, a load side fixed contact having a load side fixed contact point, a movable contact having a first movable contact point and a second movable contact point that make contact with and separate from the power supply side fixed contact point and the load side fixed contact point at both ends, a movable contact holder that rotates the movable contact, a power supply side arc extinguishing section that extinguishes an arc generated between the power supply side fixed contact point and the first movable contact point, and a load side arc extinguishing section that extinguishes an arc generated between the load side fixed contact point and the second movable contact point, the case includes side walls facing each other and a peripheral wall rising from the edges of the side walls, and is composed of a first divided case and a second divided case that are detachably divided in the width direction, wherein a first concave portion in which the first movable contact point can move is formed on the peripheral wall on the extension line of the moving path of the first movable contact point in the first divided case, and a second concave portion in which the second movable contact point can move is formed on the peripheral wall on the extension line of the moving path of the second movable contact point. A current interruption section characterized by this.

2. The current interruption section according to claim 1, wherein the power supply side arc extinguishing section is arranged over the entire moving path of the first movable contact point, and the load side arc extinguishing section is arranged over the entire moving path of the second movable contact point.

3. The power supply side arc extinguishing section includes an arc extinguishing grid in which a pair of grid arm portions extend from a grid main body to both sides of the moving path of the first movable contact point and are arranged in layers along the moving path of the first movable contact point. The current interruption section according to claim 1 or 2, wherein the load side arc extinguishing section includes an arc extinguishing grid in which a pair of grid arm portions extend from a grid main body to both sides of the moving path of the second movable contact point and are arranged in layers along the moving path of the second movable contact point.

4. The current interruption section according to claim 3, wherein the power supply side arc extinguishing section and the load side arc extinguishing section include a pair of arc extinguishing members that surround the pair of grid arm portions of the arc extinguishing grid and are arranged on both sides of the moving paths of the first movable contact point and the second movable contact point to generate ablation gas.

5. The pair of arc extinguishing members of the power supply side arc extinguishing section extend from the power supply side fixed contact point to the peripheral wall where the first concave portion is formed. The pair of arc extinguishing members of the load side arc extinguishing part is arranged to extend from the load side fixed contact to the peripheral wall where the second concave part is formed, according to the current interrupting part described in claim 4.

6. A method for assembling the current interrupting part according to any one of claims 1 to 5, A first assembling step of incorporating the power supply side fixed contact and the load side fixed contact into the first divided case, A second assembling step of incorporating the movable contact and the movable holder into the first divided case and holding the movable holder so that the first movable contact moves to the first concave part and the second movable contact moves to the second concave part, A third assembling step of incorporating the power supply side arc extinguishing part and the load side arc extinguishing part into the first divided case, A fourth assembling step of rotating the movable holder to move the first movable contact and the second movable contact inside the first divided case, A fifth assembling step of butting and fixing the peripheral wall of the first divided case and the peripheral wall of the second divided case, characterized by a method for assembling the current interrupting part.

7. In the fifth assembling step, the first convex part formed on the peripheral wall of the second divided case is fitted into the first concave part formed on the peripheral wall of the first divided case, and the second convex part formed on the peripheral wall of the second divided case is fitted into the second concave part formed on the peripheral wall of the first divided case, according to the method for assembling the current interrupting part described in claim 6.

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