Circuit breaker

Abstract

To realize an appropriate discharge of an arc gas, and suppress consumption of a blockage protection piece in a circuit breaker.SOLUTION: A circuit breaker 11 includes: a shielding plate 24; a blocking protection piece 25; and a resin member 26. An arc gas discharge port 36 is formed in the shielding plate 24. The blocking protection piece 25 blocks the discharge port 36 on one side, and covers a fixed contact 21 on the other side. The resin member 26 is attached to the other side of the blocking protection piece 25 to cover the blocking protection piece 25.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a circuit breaker.

Background Art

[0002] As shown in Patent Document 1, a shielding plate having an arc gas discharge port is provided in the arc extinguishing chamber of a circuit breaker. The shielding plate is provided with a closing piece that closes the discharge port during normal times like a lead valve and opens the discharge port when arc gas is generated.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is also a structure in which the closing piece is extended downward to cover the fixed contact in the arc extinguishing chamber to serve as a closing protection piece for protecting the fixed contact from the arc. However, due to the structure in which the closing protection piece bends or flexes when receiving arc gas to open the discharge port, its thickness has to be limited, and there is a possibility that the heat capacity is insufficient and it is consumed by the arc. An object of the present invention is to realize appropriate discharge of arc gas in a circuit breaker and suppress consumption of the closing protection piece.

Means for Solving the Problems

[0005] A circuit breaker according to an aspect of the present invention includes a shielding plate, a closing protection piece, and a resin member. The shielding plate has an arc gas discharge port formed therein. The closing protection piece closes the discharge port on one side and covers the fixed contact on the other side. The resin member is attached to the other side of the closing protection piece to cover the closing protection piece.

Effects of the Invention

[0006] According to the present invention, since the other side of the blocking protection piece is covered with a resin member, the thickness of the blocking protection piece can be restricted to achieve appropriate discharge of arc gas and suppress consumption of the blocking protection piece by the arc.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

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Figure 8

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Figure 10

Figure 11

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Figure 15

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Figure 17

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Figure 21

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Figure 23

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that each drawing is schematic and may be different from the actual one. Further, the following embodiments illustrate devices and methods for embodying the technical idea of the present invention, and do not specify the configuration to the following. That is, various modifications can be made to the technical idea of the present invention within the technical scope described in the claims.

[0009] 《First Embodiment》 《Configuration》 In the following description, three mutually orthogonal directions are, for convenience, the longitudinal direction, the width direction, and the depth direction. FIG. 1 is a diagram showing the circuit breaker 11. Here, the circuit breaker 11 is shown as viewed from one side in the longitudinal direction, one side in the width direction, and the front in the depth direction. The circuit breaker 11, also called a non-fuse breaker, automatically shuts off the circuit when an abnormal overcurrent is detected due to an overload or a short circuit, and protects against damage caused by the overcurrent. Of the longitudinal direction, one side is the power supply side and the other side is the load side. The circuit breaker 11 includes a case 12 and a middle cover 13 as a resin housing.

[0010] FIG. 2 is a diagram showing a cross section of the circuit breaker 11. Here, on the power supply side of the circuit breaker 11, a cross-section along the longitudinal direction and the depth direction, passing through the center of the first pole located on one side in the width direction among the three poles arranged in the width direction, is shown as viewed from one side in the width direction. The circuit breaker 11 includes a fixed contact 21, a movable contact 22, an arc extinguishing device 23, a shielding plate 24, a closing protection piece 25, and a resin member 26. The fixed contact 21 is a strip-shaped conductor. An electric circuit is connected to the end on the outer side in the longitudinal direction via an aluminum terminal plate, and a fixed contact point 31 is formed on the surface facing the front in the depth direction at the end on the inner side in the longitudinal direction.

[0011] The movable contact 22 is a rod-shaped conductor and is rotatably supported between the closed pole position and the open pole position. As viewed from one side in the width direction, the counterclockwise direction is the closed pole direction, and the clockwise direction is the open pole direction. A movable contact point 32 is formed at the tip side of the surface of the movable contact 22 facing the closed pole direction. When the movable contact 22 is in the closed pole position, the movable contact point 32 contacts the fixed contact point 31 to be in the closed pole state, and when the movable contact 22 is in the open pole position, the movable contact point 32 separates from the fixed contact point 31 to be in the open pole state. The arc extinguishing device 23 is composed of a plurality of magnetic plates formed with V-shaped notches called grids, and extinguishes the arc at the time of opening the pole by cooling, dividing, and stretching. The space where the arc extinguishing device 23 is arranged becomes the arc extinguishing chamber 27.

[0012] Figure 3 is a diagram showing the fixed contact 21. In the figure, (a) shows the state of the fixed contact 21 as viewed from the inner side in the longitudinal direction, one side in the width direction, and the front in the depth direction. (b) in the figure shows the state of the fixed contact 21 as viewed from one side in the width direction. The fixed contact 21 is strip-shaped along the longitudinal direction and the width direction, and the end on the outer side in the longitudinal direction is the front in the depth direction, and the end on the inner side in the longitudinal direction is the back in the depth direction, and it is bent in steps. The central step portion 35 extends obliquely toward the back in the depth direction as it goes toward the inner side in the longitudinal direction, and the surfaces facing the inner side in the longitudinal direction and the front in the depth direction face the tips of the arc extinguishing device 23 and the movable contact 22 (Figure 2). The inner side in the longitudinal direction of the fixed contact 21 is U-bent, and the tip extends toward the outer side in the longitudinal direction at the front in the depth direction.

[0013] FIG. 4 is a view showing the shielding plate 24. Here, the middle cover 13 and the blocking protection piece 25 in the circuit breaker 11 are omitted in the drawing, and the shielding plate 24 is shown as seen from the outside in the longitudinal direction, one side in the width direction, and the front in the depth direction. The shielding plate 24 is made of a resin such as polyester, which is excellent in heat resistance, and is substantially square when viewed from the longitudinal direction and formed in a flat plate shape along the longitudinal direction and the width direction. The edges on both sides in the width direction of the shielding plate 24 are inserted into the grooves of the case 12 and the grooves of the middle cover 13 (not shown). An outlet 36 penetrating in the thickness direction is formed at the front end in the depth direction of the shielding plate 24. The outlet 36 is a long hole extending in the width direction, and a total of four are arranged in two rows in the width direction and two rows in the depth direction. The two outlets 36 arranged at the back in the depth direction have a larger opening area than the two outlets 36 arranged at the front in the depth direction.

[0014] FIG. 5 is a view showing the blocking protection piece 25. In the figure, (a) shows the blocking protection piece 25 as seen from the outside in the longitudinal direction, one side in the width direction, and the back in the depth direction. The blocking protection piece 25 is made of, for example, aramid paper or fiber paper, which is excellent in electrical insulation and arc resistance and has flexibility. The blocking protection piece 25 includes a fixing portion 41, a blocking portion 42, and a protection portion 43. The fixing portion 41 is substantially square when viewed from the longitudinal direction and is in the shape of a sheet along the width direction and the depth direction. It is overlapped on the outer peripheral surface facing the outside in the longitudinal direction of the shielding plate 24, and the edges on both sides in the width direction together with the shielding plate 24 are inserted into the grooves of the case 12 and the grooves of the middle cover 13. The fixing portion 41 covers the outer peripheral surface of the shielding plate 24 except for the region where the outlet 36 is formed, that is, except for the front end in the depth direction.

[0015] The blocking part 42 is formed in front of the fixing part 41 in the depth direction, is substantially square when viewed from the longitudinal direction, is in a sheet shape along the width direction and the depth direction, and closes all the discharge ports 36 by covering the front end part in the depth direction of the outer peripheral surface of the shielding plate 24. The blocking part 42 has a width dimension smaller than the width dimension of the fixing part 41, only the rear base end in the depth direction is supported, and both ends in the width direction and the front tip in the depth direction are free. On both sides in the width direction of the blocking part 42, on the base end side at the rear in the depth direction, flanges 44 bent outward in the longitudinal direction are formed. The blocking protection piece 25 is formed with a notch 45 at the joint between the fixing part 41 and the blocking part 42 on the outer peripheral surface to facilitate bending. (b) in the figure shows the state of the notch 45 viewed from one side in the width direction. The notch 45 is a groove with a substantially V-shaped cross section concave inward in the longitudinal direction and extending linearly in the width direction. The blocking part 42 bends outward in the longitudinal direction at the notch 45 when receiving the arc gas.

[0016] The protection part 43 is formed at the rear in the depth direction of the fixing part 41, obliquely extends toward the rear in the depth direction as it goes toward the inner side in the longitudinal direction, is in a sheet shape that is substantially square when viewed from the direction perpendicular to the surface, and covers the surface facing the inner side in the longitudinal direction and the front in the depth direction at the step part 35. The resin member 26 is attached to the protection part 43. Figure 6 is a view showing the resin member 26. (a) in the figure shows the state of the resin member 26 viewed from the rear in the insertion direction, one side in the width direction, and the inner side in the thickness direction. (b) in the figure shows the state of the resin member 26 viewed from the inner side in the thickness direction. (c) in the figure shows the state of the resin member 26 viewed from one side in the width direction. (d) in the figure shows the state of the resin member 26 viewed from the rear in the insertion direction. The insertion direction refers to the insertion direction as viewed from the resin member 26 and is opposite to the insertion direction as viewed from the protection part 43.

[0017] The resin member 26 is made of a resin such as polyamide that is excellent in heat resistance, is substantially square when viewed from the thickness direction, is substantially plate-shaped along the insertion direction and the width direction, and is inserted into and fixed to the protection part 43. The inner peripheral surface of the resin member 26 facing the inner side in the thickness direction serves as a mating surface with the protection part 43. On both sides in the width direction inside the resin member 26 in the thickness direction, pressing plates 51 spaced apart from the inner peripheral surface in the thickness direction are formed, and a pair of slide grooves 52 facing each other are formed by the gap between the inner peripheral surface and the pressing plates 51. The slide grooves 52 extend in the insertion direction, and the back in the insertion direction is open. On the resin member 26, on the inner peripheral surface in front of the insertion direction, an end surface 53 facing the back in the insertion direction is formed by a step. The end surface 53 extends along the width direction from one slide groove 52 to the other slide groove 52. When inserting the pair of slide grooves 52 into the protection part 43, the separation distance of the pressing plates 51 from the inner peripheral surface of the resin member 26 and the separation distance between the slide grooves 52 are set so as to be press-fitted (tight fit).

[0018] FIG. 7 is a view showing the closing protection piece 25 with the resin member 26 attached thereto. Here, the state of the closing protection piece 25 with the resin member 26 attached to the protection part 43 is shown as viewed from the outside in the longitudinal direction, one side in the width direction, and the back in the depth direction. A pair of slide grooves 52 are inserted into the protection part 43, and when the tip of the protection part 43 abuts against the end surface 53, the attachment of the resin member 26 is completed. The protection part 43 and the resin member 26 are fitted together by press-fitting. Therefore, they are integrated so that the resin member 26 does not easily fall off from the protection part 43.

[0019] FIG. 8 is a view showing the installation state of the closing protection piece 25. In the figure, (a) shows a shielding plate 24 with the discharge port 36 blocked by the blocking portion 42, as viewed from the outer side in the longitudinal direction, one side in the width direction, and the front in the depth direction. On the outer peripheral surface of the shielding plate 24 facing the outer side in the longitudinal direction, the fixing portion 41 is overlapped with the back in the depth direction, and the blocking portion 42 is overlapped with the front in the depth direction. Thereby, the blocking portion 42 blocks all the discharge ports 36, preventing foreign matters and dust from entering the arc extinguishing chamber 27. In the figure, (b) shows a protective portion 43 covered by the resin member 26, as viewed from the inner side in the longitudinal direction, one side in the width direction, and the front in the depth direction. The protective portion 43 covering the step portion 35 has substantially the entire surface facing the inner side in the longitudinal direction and the front in the depth direction covered by the resin member 26.

[0020] FIG. 9 is a view showing the bent blocking and protecting piece 25. Here, it shows the state of the bent blocking and protecting piece 25 as viewed from the outer side in the longitudinal direction, one side in the width direction, and the front in the depth direction. The arc extinguishing device 23 is arranged inside the shielding plate 24 in the longitudinal direction. Inside the arc extinguishing device 23, arc gas is generated when the surrounding air and metal rapidly heated by the arc during interruption are vaporized. Pushed by this arc gas, the blocking portion 42 bends or bends outward in the longitudinal direction at the notch 45, and the arc gas is discharged from the opened discharge port 36. If the blocking portion 42 bends due to elastic deformation, the blocking portion 42 will recover after the arc gas is discharged. On the other hand, when it bends at the notch 45 due to plastic deformation, the blocking portion 42 remains bent even after the arc gas is discharged.

[0021] 《Function and Effect》 Next, the main function and effect of the first embodiment will be described. The circuit breaker 11 includes a shielding plate 24, a closing protection piece 25, and a resin member 26. The shielding plate 24 has an arc gas discharge port 36 formed therein. The closing protection piece 25 closes the discharge port 36 on one side and covers the fixed contact 21 of the arc extinguishing chamber 27 on the other side. The resin member 26 is attached to the other side of the closing protection piece 25 and covers the closing protection piece 25. In this way, since the other side of the closing protection piece 25 is covered by the resin member 26, the thickness of the closing protection piece 25 can be limited to achieve appropriate discharge of the arc gas and suppress the consumption of the closing protection piece 25 by the arc.

[0022] The resin member 26 has a pair of slide grooves 52 formed facing each other, and is attached by inserting the pair of slide grooves 52 into the closing protection piece 25. Thereby, the resin member 26 can be easily attached to the closing protection piece 25. The slide groove 52 is press-fitted into the closing protection piece 25. Thereby, it is possible to prevent the resin member 26 from falling off from the closing protection piece 25. The closing protection piece 25 has a closing portion 42 that closes the discharge port 36. When receiving the arc gas, the closing portion 42 bends or flexes outward to open the discharge port 36. Thereby, the intrusion of dust into the arc extinguishing chamber 27 can be suppressed by the closing protection piece 25 during normal times, and appropriate discharge of the arc gas can be achieved when the arc gas is generated. In this way, the closing protection piece 25 is required to have the function of closing the discharge port 36 during normal times and opening the discharge port 36 when receiving the arc gas. Therefore, there is a constraint that the thickness must be limited.

[0023] The closing protection piece 25 is formed with a notch 45 that makes it easier to bend the closing portion 42. Thereby, when receiving the arc gas, the closing portion 42 can be bent at the notch 45 to appropriately discharge the arc gas. The closing protection piece 25 is formed with a flange 44 on the base end side of the closing portion 42. Thereby, the strength of the closing portion 42 is improved, so that instead of bending the closing portion 42, it can be actively bent at the notch 45. There are a plurality of discharge ports 36 along the base end side to the tip side of the blocking portion 42. The discharge port 36 on the base end side of the blocking portion 42 has a larger opening area than the discharge port 36 on the tip side. Thereby, a sufficient flow path for discharging the arc gas can be secured even at the discharge port 36 on the base end side. That is, the blocking portion 42 has a structure that falls outward in the longitudinal direction with the notch 45 as the center when viewed from the width direction. Therefore, the blocking portion 42 approaches the discharge port 36 on the base end side more than the discharge port 36 on the tip side, and the flow path for discharging the arc gas becomes narrow, which is a countermeasure for this.

[0024] Next, a comparative example will be described. The comparative example is the same as the first embodiment described above except that the resin member 26 is omitted. Therefore, the same reference numerals are given to the common configurations, and detailed descriptions are omitted. FIG. 10 is a diagram showing a comparative example. Here, a state of the protection portion 43 exposed in the arc extinguishing chamber 27 is shown when viewed from the inner side in the longitudinal direction, one side in the width direction, and the front in the depth direction. The arc at the time of interruption is stretched outward in the longitudinal direction as shown by the thick arrow. The protection portion 43 can protect the step portion 35 from the arc by covering the step portion 35 of the fixed contact 21. However, since the blocking protection piece 25 has a structure that bends or buckles when receiving the arc gas to open the discharge port 36, the thickness has to be limited. Therefore, the protection portion 43 has insufficient heat capacity and may be consumed by the arc.

[0025] 《Second Embodiment》 《Configuration》 The second embodiment shows another aspect regarding the fitting of the protection portion 43 and the resin member 26. The other configurations are the same as those of the first embodiment described above. Therefore, the same reference numerals are given to the common configurations, and detailed descriptions are omitted. FIG. 11 is a diagram showing the blocking protection piece 25. Here, the blocking protection piece 25 is shown as seen from the outer side in the longitudinal direction, one side in the width direction, and the back in the depth direction. An opening 61 (recess) penetrating in the thickness direction is formed in the protection part 43. The opening 61 is square when the protection part 43 is viewed from a direction perpendicular to the surface.

[0026] FIG. 12 is a view showing the resin member 26. (a) in the figure shows the resin member 26 as seen from the back in the insertion direction, one side in the width direction, and the inner side in the thickness direction. (b) in the figure shows the resin member 26 as seen from the inner side in the thickness direction. (c) in the figure shows the resin member 26 as seen from one side in the width direction. (d) in the figure shows the resin member 26 as seen from the back in the insertion direction. A convex portion 62 that fits into the opening 61 is formed on the mating surface of the resin member 26 with the protection part 43. The convex portion 62 protrudes toward the inner side in the thickness direction and has a shape along a right-angled triangle when viewed from the width direction, and includes an inclined surface 63 and an end surface 64. The inclined surface 63 is the hypotenuse of the right-angled triangle when viewed from the width direction and becomes higher toward the inner side in the thickness direction as it goes toward the front in the insertion direction. The end surface 64 is one of the adjacent sides sandwiching the right angle of the right-angled triangle when viewed from the width direction and faces the front in the insertion direction. When inserting the pair of slide grooves 52 into the protection part 43, the separation distance between the pressing plate 51 and the inner peripheral surface of the resin member 26 and the separation distance between the slide grooves 52 are set so as not to cause press-fitting (tight fitting).

[0027] FIG. 13 is a view showing the blocking protection piece 25 with the resin member 26 attached. Here, the closed protection piece 25 with the resin member 26 attached to the protection part 43 is shown as seen from the outer side in the longitudinal direction, one side in the width direction, and the back in the depth direction. A pair of slide grooves 52 are inserted into the protection part 43, and when the tip of the protection part 43 abuts against the end face 53, the attachment of the resin member 26 is completed. The protection part 43 and the resin member 26 have an opening 61 and a convex part 62 that fit together. When inserting the pair of slide grooves 52 into the protection part 43, the protection part 43 is bent by being pushed by the inclined surface 63 of the convex part 62, and when the opening 61 and the convex part 62 fit together, the protection part 43 is restored, and the end face 64 of the convex part 62 is caught by the opening 61. Therefore, they are integrated so that the resin member 26 does not easily fall off from the protection part 43.

[0028] 《Function and Effect》 Next, the main function and effect of the second embodiment will be described. An opening 61 is formed on the mating surface of the closed protection piece 25 with the resin member 26. On the resin member 26, a convex part 62 that fits into the opening 61 is formed on the mating surface with the closed protection piece 25. The convex part 62 includes an inclined surface 63 and an end face 64. The inclined surface 63 becomes higher in the thickness direction toward the front in the insertion direction. The end face 64 faces the front in the insertion direction. Thereby, the resin member 26 can be easily attached to the protection part 43, and the resin member 26 can be prevented from falling off from the protection part 43. Regarding other function and effect brought about by the common configuration, it is the same as that of the first embodiment described above.

[0029] 《Modification》 In the second embodiment, the configuration of forming the opening 61 penetrating the protection part 43 has been described, but it is not limited to this. That is, any shape may be used as long as it can fit with the convex part 62. Therefore, instead of the opening 61, a concave part that is concave outward in the thickness direction may be formed on the mating surface of the protection part 43. In the second embodiment, the configuration in which the recess (opening 61) is formed in the protection part 43 and the convex part 62 is formed in the resin member 26 has been described, but the present invention is not limited thereto. That is, a configuration in which a convex part is formed in the protection part 43 and a recess is formed in the resin member 26 may be adopted.

[0030] 《Third Embodiment》 《Configuration》 The third embodiment shows another aspect regarding the fitting between the protection part 43 and the resin member 26. Since the other configurations are the same as those of the first embodiment described above, the same reference numerals are given to the common configurations, and detailed descriptions thereof are omitted. FIG. 14 is a view showing the closing protection piece 25. In the figure, (a) shows a state in which the closing protection piece 25 is viewed from the outer side in the longitudinal direction, one side in the width direction, and the back in the depth direction. In the protection part 43, notches 71 (recesses) are formed on two sides facing each other in the width direction.

[0031] In the figure, (b) shows a state in which the notch 71 is viewed from the inner side in the thickness direction of the protection part 43. The insertion direction refers to the insertion direction as viewed from the protection part 43, and is opposite to the insertion direction as viewed from the resin member 26. The notch 71 is recessed toward the inner side in the width direction and has a shape along a right triangle when viewed from the thickness direction, and includes an inclined surface 72 and an end surface 73. The inclined surface 72 is the hypotenuse of the right triangle when viewed from the thickness direction, and becomes deeper toward the inner side in the width direction as it goes deeper into the back in the insertion direction. The end surface 73 is one of the adjacent sides sandwiching the right angle of the right triangle when viewed from the thickness direction, and faces the front in the insertion direction.

[0032] FIG. 15 is a view showing the resin member 26. In the figure, (a) shows the resin member 26 as viewed from the back in the insertion direction, one side in the width direction, and the inner side in the thickness direction. (b) in the figure shows the resin member 26 as viewed from the inner side in the thickness direction. (c) in the figure shows the resin member 26 as viewed from one side in the width direction. (d) in the figure shows the resin member 26 as viewed from the back in the insertion direction. In the resin member 26, a convex portion 74 that fits into the notch 71 is formed at the back in the insertion direction of the pair of slide grooves 52. The vicinity of the convex portion 74 has the pressing plate 51 removed. The convex portion 74 protrudes toward the inner side in the width direction and has a shape along a right triangle when viewed from the thickness direction, and includes an inclined surface 75 and an end surface 76. The inclined surface 75 forms the hypotenuse of the right triangle when viewed from the thickness direction and becomes higher toward the inner side in the width direction as it goes toward the front in the insertion direction. The end surface 76 forms one of the adjacent sides sandwiching the right angle of the right triangle when viewed from the width direction and faces the front in the insertion direction. When inserting the pair of slide grooves 52 into the protection part 43, the separation distance between the pressing plate 51 and the inner peripheral surface of the resin member 26 and the separation distance between the slide grooves 52 are set so as not to be press-fitted (snug fit).

[0033] Figure 16 is a view showing the closing protection piece 25 with the resin member 26 attached. Here, it shows the state of the closing protection piece 25 with the resin member 26 attached to the protection part 43 as viewed from the outer side in the vertical direction, one side in the width direction, and the back in the depth direction. A pair of slide grooves 52 are inserted into the protection part 43, and when the tip of the protection part 43 abuts against the end surface 53, the attachment of the resin member 26 is completed. In the protection part 43 and the resin member 26, the notch 71 and the convex portion 74 are fitted together. When inserting the pair of slide grooves 52 into the protection part 43, the protection part 43 is bent so that the convex portion 74 is avoided and the protection part 43 protrudes outward in the thickness direction and inserted. When the tip of the protection part 43 abuts against the end surface 53, when the protection part 43 is aligned with the mating surface of the resin member 26, the notch 71 and the convex portion 74 are fitted together and are hooked by the opposing end surfaces 73 and 76. Therefore, they are integrated so that the resin member 26 does not easily fall off from the protection part 43.

[0034] 《Function and Effect》 Next, the main effects of the third embodiment will be described. The closing protection piece 25 has notches 71 formed on two opposing sides. The resin member 26 has convex portions 74 formed in a pair of slide grooves 52 that fit into the notches 71. This enables the resin member 26 to be easily attached to the protection portion 43. The convex portion 74 has an end face 76. The end face 76 faces forward in the insertion direction. The notch 71 has an end face 73. The end face 73 faces forward in the insertion direction. As a result, the end face 76 and the end face 73 face each other, suppressing the resin member 26 from falling off the protection portion 43. Other effects brought about by the common configuration are the same as those of the first embodiment described above.

[0035] <<Modification Example>> In the third embodiment, the configuration in which the notches 71 and the convex portions 74 are formed along a right triangle has been described, but the present invention is not limited thereto. Any shape may be used as long as the end faces 73 and 76 that fit into each other and face each other can be formed. In the third embodiment, the configuration in which the protection portion 43 is formed with a recess (notch 71) and the resin member 26 is formed with a convex portion 74 has been described, but the present invention is not limited thereto. That is, a configuration in which the protection portion 43 is formed with a convex portion and the resin member 26 is formed with a recess may also be used.

[0036] <<Fourth Embodiment>> <<Configuration>> The fourth embodiment employs a resin member 83 instead of the resin member 26 and shows the fitting between the protection portion 43 and the resin member 83. Since the other configurations are the same as those of the first embodiment described above, the common configurations are denoted by the same reference numerals and detailed descriptions thereof are omitted. FIG. 17 is a view showing the closing protection piece 25. (a) in the figure shows the state of the blocking protection piece 25 as viewed from the outer side in the longitudinal direction, one side in the width direction, and the back in the depth direction. (b) in the figure shows the state of the protection part 43 as viewed from a direction perpendicular to the plane. In the center of the protection part 43, a through hole 81 penetrating in the thickness direction is formed. The through hole 81 is circular when the protection part 43 is viewed from a direction perpendicular to the plane, and a cross-shaped notch 82 is formed on the outer side in the radial direction when the protection part 43 is viewed from a direction perpendicular to the plane.

[0037] Figure 18 is a view showing the resin member 83. (a) in the figure shows the state of the resin member 83 as viewed from the back in the insertion direction, one side in the width direction, and the inner side in the thickness direction. (b) in the figure shows the state of the resin member 83 as viewed from the width direction. The resin member 83 is substantially square when viewed from the thickness direction, is substantially plate-shaped along the protection part 43, and is fixed by being overlapped with the protection part 43. On the mating surface of the resin member 83 with the protection part 43, a convex part 84 that fits into the through hole 81 is formed. The convex part 84 is columnar and convex toward the inner side in the thickness direction, and a flange 85 protruding outward in the radial direction is formed on the tip side. The outer diameter of the base end side of the convex part 84 is smaller than the inner diameter of the through hole 81, and the outer diameter of the flange 85 is smaller than the distance between the tips on the outer side in the radial direction among the linearly arranged notches 82.

[0038] Figure 19 is a view showing the blocking protection piece 25 with the resin member 83 mounted. Here, it shows the state of the blocking protection piece 25 with the resin member 83 mounted on the protection part 43 as viewed from the outer side in the longitudinal direction, one side in the width direction, and the back in the depth direction. The resin member 83 is overlapped with the protection part 43, and the convex part 84 with the flange 85 fits into the through hole 81 of the protection part 43, thereby completing the attachment of the resin member 83. When the resin member 83 is overlapped with the protection part 43, the periphery of the through hole 81 is bent by being pushed by the flange 85, and when it exceeds the flange 85, the periphery of the through hole 81 is restored and caught by the flange 85. Therefore, it is integrated so that the resin member 83 does not easily fall off from the protection part 43. The resin member 83 has no anti-rotation function with respect to the protection part 43, but is circumferentially positioned by being assembled to the case 12.

[0039] 《Operational Effects》 Next, the main operational effects of the fourth embodiment will be described. In the closing protection piece 25, a through hole 81 with a notch 82 is formed on the mating surface with the resin member 83. In the resin member 83, a convex portion 84 with a flange 85 that fits into the through hole 81 is formed on the mating surface with the closing protection piece 25. Thereby, the resin member 83 can be easily attached to the protection portion 43, and the resin member 83 can be prevented from falling off from the protection portion 43. Regarding other operational effects brought about by the common configuration, they are the same as those of the first embodiment described above.

[0040] 《Fifth Embodiment》 《Configuration》 The fifth embodiment shows another aspect regarding the fitting of the protection portion 43 and the resin member 83. Since the other configurations are the same as those of the fourth embodiment described above, the same reference numerals are given to the common configurations, and detailed descriptions are omitted. FIG. 20 is a view showing the closing protection piece 25. (a) in the figure shows the state of the closing protection piece 25 viewed from the outside in the longitudinal direction, one side in the width direction, and the back in the depth direction. (b) in the figure shows the state of the protection portion 43 viewed from a direction perpendicular to the surface. A through hole 91 penetrating in the thickness direction is formed at the center of the protection portion 43.

[0041] FIG. 21 is a view showing the resin member 83 before heat caulking. (a) in the figure shows the state of the resin member 83 before heat caulking viewed from the back in the insertion direction, one side in the width direction, and the inside in the thickness direction. (b) in the figure shows the state of the resin member 83 before heat caulking viewed from the width direction. On the mating surface of the resin member 83 with the protection portion 43, a convex portion 92 that fits into the through hole 91 is formed. The convex portion 92 is a columnar shape that protrudes toward the inside in the thickness direction, and the outer diameter is smaller than the inner diameter of the through hole 91. FIG. 22 is a view showing the resin member 83 after heat caulking. In the figure, (a) shows the resin member 83 after heat caulking, as viewed from the back in the insertion direction, from one side in the width direction, and from the inner side in the thickness direction. (b) in the figure shows the resin member 83 after heat caulking, as viewed from the width direction. By performing heat caulking on the convex portion 92, a flange is formed at the tip. The outer diameter of the flange is larger than the inner diameter of the through hole 91.

[0042] Figure 23 is a view showing the closing protection piece 25 to which the resin member 83 is attached. Here, a state of the closing protection piece 25 with the resin member 83 attached to the protection part 43 is shown as viewed from the outer side in the longitudinal direction, from one side in the width direction, and from the back in the depth direction. The resin member 83 is overlapped on the protection part 43, and by performing heat caulking on the convex portion 92, the attachment of the resin member 83 is completed. By performing heat caulking on the convex portion 92, a flange is formed at the tip and is caught around the through hole 91. Therefore, they are integrated so that the resin member 83 does not easily fall off from the protection part 43.

[0043] 《Function and Effect》 Next, the main function and effect of the fifth embodiment will be described. In the closing protection piece 25, a through hole 91 is formed on the mating surface with the resin member 83. In the resin member 83, a convex portion 92 that fits into the through hole 91 is formed on the mating surface with the closing protection piece 25. The closing protection piece 25 and the resin member 83 are attached by heat caulking the convex portion 92 fitted into the through hole 91. Thereby, the resin member 83 can be easily attached to the protection part 43, and the resin member 83 can be prevented from falling off from the protection part 43. Other function and effect brought about by the common configuration are the same as those of the first embodiment described above.

[0044] Although described above with reference to a limited number of embodiments, the scope of rights is not limited thereto, and modifications of the embodiments based on the above disclosure are obvious to those skilled in the art.

Explanation of Reference Numerals

[0045] 11…Circuit breaker, 12…Case, 13…Middle cover, 21…Fixed contact, 22…Movable contact, 23…Arc extinguishing device, 24…Shielding plate, 25…Blocking protection piece, 26…Resin member, 27…Arc extinguishing chamber, 31…Fixed contact point, 32…Movable contact point, 35…Step portion, 36…Outlet, 41…Fixing portion, 42…Blocking portion, 43…Protection portion, 44…Flange, 51…Plate, 52…Slide groove, 53…End face, 61…Opening, 62…Protrusion, 63…Inclined surface, 64…End face, 71…Notch, 72…Inclined surface, 73…End face, 74…Protrusion, 75…Inclined surface, 76…End face, 81…Through hole, 83…Resin member, 84…Protrusion, 85…Flange, 91…Through hole, 92…Protrusion

Claims

1. A shielding plate formed with an arc gas discharge port, A closing protection piece that closes the discharge port on one side and covers the fixed contact on the other side, A circuit breaker comprising a resin member attached to the other side of the closing protection piece to cover the closing protection piece.

2. The circuit breaker according to claim 1, wherein the resin member is formed with a pair of slide grooves facing each other and is attached by inserting the pair of slide grooves into the closing protection piece.

3. The circuit breaker according to claim 2, wherein the slide grooves are press-fitted into the closing protection piece.

4. One of a convex portion and a concave portion is formed on the closing protection piece on the mating surface with the resin member, The other of the convex portion and the concave portion that fits into one of the convex portion and the concave portion is formed on the resin member on the mating surface with the closing protection piece, The convex portion, An inclined surface that becomes higher toward the front in the insertion direction, The circuit breaker according to claim 2, further comprising an end surface facing the front in the insertion direction.

5. One of a convex portion and a concave portion is formed on two opposite sides of the closing protection piece, The circuit breaker according to claim 2, wherein the resin member is formed with the other of the convex portion and the concave portion that fits into one of the convex portion and the concave portion in a pair of the slide grooves.

6. The convex portion has an end surface facing the front in the insertion direction, The circuit breaker according to claim 5, wherein the concave portion has an end surface facing the front in the insertion direction.

7. A cut-through hole is formed on the closing protection piece on the mating surface with the resin member, The circuit breaker according to claim 1, wherein the resin member is formed with a convex portion with a flange that fits into the through hole on the mating surface with the closing protection piece.

8. A through hole is formed on the closing protection piece on the mating surface with the resin member, The resin member is formed with a convex portion that fits into the through hole on the mating surface with the closing protection piece, The circuit breaker according to claim 1, wherein the closing protection piece and the resin member are attached by thermally caulking the convex portion fitted into the through hole.

9. The circuit breaker according to claim 1, wherein the closing portion of the closing protection piece that closes the discharge port opens the discharge port by bending or buckling outward when receiving arc gas.

10. The circuit breaker according to claim 9, wherein the blocking protection piece is formed with a notch that facilitates bending of the blocking portion.

11. The circuit breaker according to claim 9, wherein a flange is formed on the base end side of the blocking portion of the blocking protection piece.

12. There are a plurality of the discharge ports along the base end side to the tip side of the blocking portion, The circuit breaker according to claim 9, wherein the discharge port on the base end side of the blocking portion has a larger opening area than the discharge port on the tip side.

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