Circuit breaker

Abstract

The present invention provides a circuit breaker that prevents damage to the switching mechanism by suppressing the outflow of large amounts of arc gas generated by the current-limiting opening operation of the movable contact into the space housing the switching mechanism. [Solution] A first space S1 housing the opening / closing contact 3, holder unit 18 and arc extinguishing device 7 and a second space S2 housing the opening / closing mechanism 4 are separated by the inner wall 2b of the case. A lower toggle passage hole 40 is formed in the inner wall of the case, which connects the first space and the second space and is connected to the holder unit, along the operating range of the lower toggle 14 of the toggle link mechanism 12. A shutter portion 32 is provided to block a part of the lower toggle passage hole from the first space side in accordance with the movement of the lower toggle when the movable contact 11 is in a current-limiting opening operation.

Description

Technical Field

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

Background Art

[0002] A circuit breaker includes, within a main body case, an opening / closing contact formed by a fixed contact having a fixed contact point and a movable contact having a movable contact point, a holder unit that rotatably supports the proximal end of the movable contact, an opening / closing mechanism having a toggle link mechanism that links between an opening / closing handle and the movable contact, and an arc extinguishing device (for example, Patent Document 1).

[0003] In this circuit breaker, when an arc and arc gas are generated between the fixed contact point and the movable contact point by the current-limiting opening operation of the movable contact, and the arc gas passes through the exhaust port of the arc extinguishing device in a strong flow, the arc is brought into contact with the grid of the arc extinguishing device in a short time to rapidly increase the arc voltage, thereby improving the breaking performance.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Inside the main body case of the circuit breaker, a first space for housing the opening / closing contact, the holder unit, and the arc extinguishing device and a second space for housing the opening / closing mechanism are partitioned by the inner wall of the case. However, the lower toggle that constitutes the toggle link mechanism of the opening / closing mechanism is connected to the holder case of the holder unit, and a lower toggle passage hole through which the lower toggle passes and that communicates the first space and the second space is formed in the inner wall of the case.

[0006] Here, if a large amount of arc gas containing metal particles and resin evaporated by the arc heat generated in the first space flows out into the second space through the lower toggle passage hole, it may adversely affect the opening and closing mechanism.

[0007] Furthermore, if a large amount of arc gas from the first space flows into the second space, the force pushing the arc in the first space into the arc extinguishing device (the flow of arc gas) will weaken, which may reduce the shutoff performance.

[0008] Therefore, the present invention aims to provide a circuit breaker that prevents a large amount of arc gas generated by the current-limiting opening operation of the movable contact from flowing out into the space housing the switching mechanism, thereby preventing an impact on the switching mechanism, and also improves the interruption performance by having the flow of arc gas act as a force that pushes the arc into the arc extinguishing device. [Means for solving the problem]

[0009] To achieve the above objective, a circuit breaker according to one aspect of the present invention houses, within a case, an opening / closing contact comprising a fixed contact having a fixed contact and a movable contact having a movable contact, a holder unit that rotatably supports the base end of the movable contact, an opening / closing mechanism comprising a toggle link mechanism connecting an opening / closing handle and the movable contact, and an arc extinguishing device. The case is divided into a first space housing the opening / closing contact, the holder unit, and the arc extinguishing device, and a second space housing the opening / closing mechanism by the inner wall of the case. The inner wall of the case has a lower toggle pass-through hole formed along the operating range of the lower toggle of the toggle link mechanism connected to the holder unit, which connects the first space and the second space, and a shutter portion that follows the operation of the lower toggle during the current-limiting opening operation of the movable contact and blocks a part of the lower toggle pass-through hole from the first space side. [Effects of the Invention]

[0010] According to the circuit breaker of the present invention, the outflow of arc gas generated by the current-limiting opening operation of the movable contact into the space housing the switching mechanism is suppressed, thereby preventing an impact on the switching mechanism. Furthermore, the flow of arc gas acts as a force that pushes the arc into the arc extinguishing device, thereby improving the interruption performance. [Brief explanation of the drawing]

[0011] [Figure 1] This is a cross-sectional view showing a circuit breaker according to the present invention. [Figure 2] This is a cross-sectional view showing the position of the lower toggle of the toggle link mechanism when the open / closed contact is in the ON position. [Figure 3] This is a perspective view showing the movable element unit. [Figure 4] This is a perspective view showing the holder case that makes up the holder unit. [Figure 5] This is a perspective view showing the holder unit with the lower toggle, movable element unit, and toggle shutter arranged on it. [Figure 6] This is a perspective view showing the shape of a toggle shutter. [Figure 7] This is a cross-sectional view showing the positions of the lower toggle and toggle shutter during the current-limiting opening operation of the movable contact. [Modes for carrying out the invention]

[0012] Next, embodiments of the present invention will be described with reference to the drawings. In the following drawings, identical 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 thickness and planar dimensions, the ratio of the thickness of each layer, etc., may differ from reality. Therefore, specific thicknesses and dimensions should be determined by referring to the following explanation. Furthermore, it should be noted that there are parts where the relationships and ratios of dimensions differ between drawings.

[0013] Furthermore, the embodiments described below illustrate devices and methods for realizing the technical concept of the present invention, and the technical concept of the present invention does not limit the materials, shapes, structures, arrangements, etc. of the components to those described below. The technical concept of the present invention can be modified in various ways within the technical scope defined by the claims described in the patent claims.

[0014] Figure 1 is a cross-sectional view of the main parts of a circuit breaker 1 of a first embodiment for three-phase (R, S, T phases) AC, connected between the power supply side and the load side of the circuit, showing the circuit structure of one of the phases that are incorporated in parallel into the main body case 2.

[0015] The circuit breaker 1 has an opening / closing mechanism 4 for opening and closing the opening / closing contacts 3, an opening / closing handle 5 for operating the opening / closing mechanism 4, and an arc extinguishing device 7 arranged inside the main body case 2. The case described in the present invention corresponds to the main body case 2.

[0016] The main case 2 is constructed by assembling a power supply-side intermediate case 2b and a load-side intermediate case (not shown) on top of a lower case 2a, and then assembling a top cover (not shown) on top of the power supply-side intermediate case 2b and the load-side intermediate case. The power supply-side main circuit terminal 8 and the load-side main circuit terminal (not shown) are fixed to the lower case 2a. The opening / closing contact 3, holder unit 18, and arc extinguishing device 7 are housed in the first space S1 enclosed by the lower case 2a and the power supply-side intermediate case 2b of the main case 2. The opening / closing mechanism 4 is housed in the second space S2 enclosed by the power supply-side intermediate case 2b and the top cover. Note that the inner wall of the case described in this invention corresponds to the power supply-side intermediate case 2b.

[0017] The switching contact 3 consists of a fixed contact 10 having a fixed contact 10a and a movable contact 11 having a movable contact 11a, the movable contact 11 being rotatably supported by a holder unit 18. The fixed contact 10 is connected to the power supply side main circuit terminal 8, and the movable contact 11 is connected to the load side main circuit terminal via the holder base 22 of the holder unit 18 and an overcurrent tripping device (not shown).

[0018] The arc extinguishing device 7 includes a plurality of grids 7a arranged in layers, and an exhaust port 7b communicating with the outside on the end side separated from the opening and closing contacts 3 of the plurality of grids 7a.

[0019] The opening and closing mechanism 4 includes a toggle link mechanism 12 that links between the movable contact 11 and the opening and closing handle 5, and a trip crossbar 13. As shown in FIG. 2, the toggle link mechanism 12 includes a lower toggle 14 whose lower part is pin-connected to the holder case 19 of the holder unit 18, an upper toggle 15 that is pin-connected to the upper part of the lower toggle 14 and a latch mechanism (not shown), and an opening and closing spring 16 disposed between the opening and closing handle 5 and the lower part of the upper toggle 15. When the trip crossbar 13 rotates counterclockwise, the movable contact 11 performs an opening operation due to the trip operation of the opening and closing mechanism 4.

[0020] Here, as shown in FIG. 2, a lower toggle passing hole 40 that communicates the first space S1 and the second space S2 is formed in the power supply side intermediate case 2b, and the lower toggle 14 passing through the lower toggle passing hole 40 is pin-connected to the holder case 19 and the upper toggle 15.

[0021] The holder unit 18 includes a mover unit 17 shown in FIG. 3 and a holder case 19 that houses the proximal end side of the mover unit 17 shown in FIG. 4.

[0022] As shown in Figure 3, the movable element unit 17 includes a holder base 22 having a connecting plate 20 and a support portion 21, a movable element pivot shaft 23 mounted on the support portion 21 to rotatably support the movable contact 11, a movable element contact pressure spring 24, and a sliding contact pressure spring 25. The support portion 21 of the holder base 22 is provided with a pair of plate-shaped sliding contacts 26 and 27 extending parallel to each other, and has an axial hole (not shown) through which the movable element pivot shaft 23 passes. A movable protective cover 28 made of synthetic resin is attached to the bottom side (movable contact 11a side) of the movable contact 11. The pair of sliding contact pressure springs 25 arranged inside the holder case 19 are positioned on the outer surfaces of the pair of sliding contacts 26 and 27 so as to surround the movable element pivot shaft 23 and apply spring force in a direction that brings the base end of the movable contact 11 into close surface contact. Furthermore, the movable contact pressure spring 24, positioned inside the holder case 19, applies a spring restoring force to the movable contact 11 in the closing direction.

[0023] As shown in Figure 4, the holder case 19 is a substantially cylindrical member made of an insulating material for mounting three-phase movable element units 17 in parallel, with three movable element passage holes 29a to 29c formed circumferentially at positions spaced apart in the longitudinal direction. In addition, two lower toggle rotation holes 30 are formed circumferentially at positions flanking the movable element passage hole 29b located in the longitudinal center of the holder case 19.

[0024] Figure 5 shows the holder case 19 with the three-phase movable unit 17, a pair of lower toggles 14, and a toggle shutter 31 mounted on it.

[0025] The movable element unit 17 has a holder base 22, a movable element pivot shaft 23, a movable element contact pressure spring 24, and a sliding contact element contact pressure spring mounted inside the holder case 19, with the movable contact element 11 positioned to protrude to the outside through the movable element opening 29. The lower toggle 14 has its lower part pin-connected inside the holder case 19, and its upper part is positioned to protrude to the outside through the lower toggle pivot hole 30.

[0026] The toggle shutter 31 is a component formed of an insulating material and, as shown in Figure 6, comprises a pair of shutter sections 32, 32 and a connecting section 33 that connects one end of the pair of shutter sections 32, 32 in the longitudinal direction. The pair of shutter sections 32, 32 are symmetrically curved elongated plates with the connecting section 33 in between, and a notch 34 is formed in the center in the longitudinal direction. An engaging section 35 is formed at one end of the notch 34 in the longitudinal direction. In addition, a projection 37 is formed on the connecting section 33 that protrudes downward. The lower toggle engaging section described in this invention corresponds to the engaging section 35, and the guide section described in this invention corresponds to the projection 37.

[0027] As shown in Figure 5, the toggle shutter 31 is positioned to cover the outer circumference of the movable element passage hole 29b in the longitudinal center of the holder case 19, with the projection 37 engaging with the periphery of the movable element passage hole 29b, and the lower toggle 14 passing through the inside of the notch 34.

[0028] Next, the operation of the circuit breaker 1 of this embodiment will be described with reference to Figure 7.

[0029] When an overcurrent flows between the power supply side main circuit terminal 8 and the load side main circuit terminal of the circuit breaker 1, the movable contact 11 begins its current-limiting opening operation. When the movable contact 11 begins its current-limiting opening operation, the holder case 19 rotates in the direction of the arrow. Along with this rotation of the holder case 19, the lower toggle 14 also moves toward the trip crossbar 13 while approaching the opening / closing spring 16.

[0030] Then, when a part of the lower toggle 14 engages with the engaging portion 35 of the shutter portion 32, the toggle shutter 31 moves together with the lower toggle 14. At this time, the projection 37 of the toggle shutter 31 slides along the periphery of the movable element passage hole 29b, guiding the toggle shutter 31 in the correct direction of movement so that the shutter portion 32 moves in a direction that shields the lower toggle passage hole 40.

[0031] Then, during the final current-limiting opening operation of the movable contact 11, the shutter portion 32 of the toggle shutter 31, which has moved along with the operation of the lower toggle 14, reduces the opening area of ​​the lower toggle passage hole 40.

[0032] Therefore, when the movable contact 11 starts the current-limiting opening operation, the opening area of ​​the lower toggle through hole 40, which connects the first space S1 and the second space S2, is set smaller by the lower toggle 14 and the shutter portion 32 of the toggle shutter 31. This suppresses the amount of arc gas containing metal particles and resin evaporated by the arc heat generated in the first space S1 that flows out into the second space S1, thus preventing any impact on the opening / closing mechanism 4.

[0033] Furthermore, it is possible to prevent a large outflow of arc gas from the first space S1, and the flow of arc gas acts as a force that pushes the arc into the arc extinguishing device, thereby improving the shutoff performance.

[0034] Furthermore, when the toggle shutter 31 moves in conjunction with the operation of the lower toggle 14, the projection 37 slides along the periphery of the movable element passage hole 29b, so that the toggle shutter 31 can be guided in the correct direction of movement so that the shutter part 32 moves in a direction that shields the lower toggle passage hole 40. [Explanation of Symbols]

[0035] 1 Circuit breaker 2. Main unit case 2a Lower case 2b Power supply side intermediate case 3. Opening / closing contacts 4. Opening and closing mechanism 5. Opening / closing handle 7 Arc extinguishing device 7a Grid 7b Exhaust port 8 Power supply side main circuit terminal 10a Fixed Contact 10 Fixed contact 11a Movable contact 11 Movable contact 18 Holder Unit 19 Holder Case 22 Holder base 12. Toggle link mechanism 13 Trip Crossbar 14 Down toggle 15 Up Toggle 16 Opening / Closing Springs 17. Movable Unit 20 connecting plates 21 Support part 22 Holder base 23. Movable element pivot axis 24. Movable element contact spring 25. Sliding contact spring 26,27 Sliding contacts 28 Movable protective cover 29a~29c Mover passing hole 30 Lower toggle rotating hole 31 Toggle Shutter 32 Shutter section 33 Connecting part 34 Notch 35 Engaging part 37 Protrusion 40 Lower toggle pass-through hole S1 1st space S2 2nd space

Claims

1. The case houses an opening / closing contact comprising a fixed contact having a fixed contact and a movable contact having a movable contact, a holder unit that rotatably supports the base end of the movable contact, an opening / closing mechanism comprising an opening / closing handle and a toggle link mechanism connecting the movable contact, and an arc extinguishing device. A first space housing the opening / closing contact, the holder unit, and the arc extinguishing device, and a second space housing the opening / closing mechanism are separated by the inner wall of the case, and a lower toggle passage hole is formed in the inner wall of the case, connecting the first space and the second space, along the operating range of the lower toggle of the toggle link mechanism connected to the holder unit. A circuit breaker characterized by having a shutter portion that blocks a part of the lower toggle passage hole from the first space side in accordance with the movement of the lower toggle when the movable contact is in a current-limiting opening operation.

2. The circuit breaker according to claim 1, characterized in that the shutter portion is slidably arranged on the outer circumference of the holder case of the holder unit and moves to a position that obstructs the lower toggle passage hole in accordance with the operation of the lower toggle.

3. The circuit breaker according to claim 2, characterized in that the shutter portion is provided with a lower toggle engaging portion that engages with the lower toggle when the movable contact is in a current-limiting opening operation and moves the shutter portion together with the lower toggle.

4. The circuit breaker according to claim 2, characterized in that the shutter portion is provided with a guide portion that guides the shutter portion so that it moves along the direction in which the lower toggle operates.

5. The holder case has a movable contact passage hole formed along the operating range of the movable contact, and the shutter portion is connected to a projection that engages with the periphery of the movable contact passage hole. The circuit breaker according to claim 4, characterized in that the projection that slides on the periphery of the movable element passage hole when the shutter portion moves is used as the guide portion.

Images