JP2023147533A - circuit breaker - Google Patents

Abstract

To prevent a risk where a terminal screw cannot be removed by a scattering substance, contained in arc gas, adhered to the terminal screw.SOLUTION: A circuit breaker comprises: a movable contactor 50 having a movable contact 51; a fixed contactor 60 having a fixed contact 61 and a terminal screw hole; a terminal screw 70 to be inserted into the terminal screw hole; and an exhaust space Ea for discharging arc gas generated when the movable contact moves away from the fixed contact. In the exhaust space provided below the terminal screw hole, a screw protection part is provided to protect a lower end side of the terminal screw from the arc gas.SELECTED DRAWING: Figure 4

Description

The present invention relates to circuit breakers.

As described in Patent Document 1, a movable contact having a movable contact and a fixed contact having a fixed contact are provided, and when the movable contact leaves the fixed contact, an arc and arc gas are generated between both the contacts. . For these purposes, an arc extinguisher is provided to immediately interrupt the arc, and an exhaust port is provided to exhaust the arc gas to the outside of the circuit breaker. In addition, in Patent Document 1, an exhaust port is provided below a terminal screw provided for connecting an electric wire to a fixed contact, and arc gas is exhausted.

Utility model registration No. 3035548

By the way, some of the contacts, arc extinguishing devices, etc. melted by the arc are included in the arc gas as scattered objects. If these scattered objects adhere to the terminal screw, the terminal screw may become unable to rotate and may not be removed.

The inventor of this case attempted to solve this problem by intensively studying this point. The problem to be solved by the present invention is to prevent the terminal screw from becoming impossible to remove due to adhesion of flying objects contained in the arc gas to the terminal screw.

In order to solve the above problems, we have developed a movable contact having a movable contact, a fixed contact having a fixed contact and a terminal screw hole, a terminal screw inserted into the terminal screw hole, and a fixed contact when the movable contact is separated from the fixed contact. A circuit breaker is provided with an exhaust space for exhausting arc gas generated in the circuit breaker, and a screw protector is provided in the exhaust space provided below the terminal screw hole to protect the lower end side of the terminal screw from the arc gas. It shall be a circuit breaker.

Additionally, the fixed contact may be provided with a vent that serves as a path for arc gas from the fixed contact to the exhaust space, and the screw protector provided in the exhaust space may be located between the terminal screw and the vent. preferable.

In addition, the exhaust space is provided with a nut that can secure the electric wire to the fixed contact by screwing with the terminal screw, and the screw protection part has a surface larger than the horizontal direction of the threaded part of the terminal screw that protrudes downward from the nut. It is preferable to have a configuration having the following.

Further, the circuit breaker includes a movable contact having a movable contact, a fixed contact having a fixed contact and a terminal screw hole, and a plurality of terminal screws inserted into the terminal screw holes, the circuit breaker having a plurality of terminal screws inserted into the terminal screw holes, The terminal screw holes are arranged at different heights, and an exhaust space for exhausting arc gas generated when the movable contact separates from the fixed contact is provided below the terminal screw hole located at a lower position. Preferably, the circuit breaker is provided with a screw protector for protecting the lower end side of the terminal screw from arc gas.

According to the present invention, it is possible to prevent the terminal screw from becoming impossible to remove due to adhesion of scattered objects contained in the arc gas to the terminal screw.

It is a perspective view of a circuit breaker in an embodiment. It is a perspective view showing the left part when the circuit breaker in an embodiment is disconnected. FIG. 3 is an enlarged view of the vicinity of the exhaust space in FIG. 2. FIG. However, the terminal screws are omitted. It is a figure showing an example of the behavior of arc gas when a screw protection member is installed. However, the broken line shows the behavior of the arc gas. FIG. 5 is an exploded perspective view of the structure shown in FIG. 4 with the crossbar and spring removed. FIG. 3 is a diagram showing the positional relationship between a ventilation hole of a fixed contact, a terminal screw, a screw protection member, and a nut. FIG. 4 is a diagram showing an example in which the screw protection member in FIG. 3 is replaced with a screw protection protrusion. FIG. 3 is a diagram showing the positional relationship between the ventilation hole of the fixed contact, the terminal screw, the screw protection protrusion, and the nut. It is a figure which shows the example which uses a nut as a screw protection part. However, the broken line shows the behavior of the arc gas.

A mode for carrying out the invention will be shown below. In addition, in the following explanation, when the terminal screw 70 is inserted into the terminal screw hole 62 and fixed, the side where the head of the terminal screw 70 is located is the upper side, and the side where the screw portion 71 is located is the lower side. .

As understood from what is shown in FIGS. 1 to 4, the circuit breaker 1 of this embodiment has a movable contact 50 having a movable contact 51, a fixed contact 61, and a terminal screw hole 62. It includes a fixed contact 60, a terminal screw 70 inserted into a terminal screw hole 62, and an exhaust space Ea for exhausting arc gas generated when the movable contact 51 leaves the fixed contact 61. This circuit breaker 1 is provided with a screw protection part that protects the lower end side of the terminal screw 70 from arc gas in the exhaust space Ea provided below the terminal screw hole 62. Therefore, it is possible to prevent the terminal screw 70 from becoming impossible to remove due to the attachment of scattered objects contained in the arc gas to the terminal screw 70.

Generally, the circuit breaker 1 includes a movable contact 50 having a movable contact 51 and a fixed contact 60 having a fixed contact 61. By moving the movable contact 50, the movable contact 51 and the fixed contact 61 can be switched between a state in which they are in contact and a state in which they are apart.

In the circuit breaker 1 of the embodiment, the fixed contact 60 is provided with a terminal screw 70 used for fixing an electric wire, and the fixed contact 60 has a terminal screw hole 62 into which the terminal screw 70 can be inserted. is provided. Although the terminal screw 70 can be screwed into a female screw, the terminal screw 70 in the embodiment can be screwed into a nut 41 provided below the terminal screw hole 62.

Furthermore, the movable contact 51 and the fixed contact 61 of the circuit breaker 1 according to the embodiment are arranged inside the case 10 which forms the main outer shell, so that the arc gas generated inside the case 10 can be guided to the outside of the case 10. It has a structure.

The circuit breaker 1 is also equipped with an arc extinguisher 42 for immediately interrupting the arc generated with the arc gas, and a dust barrier 43 for preventing dust from entering the circuit breaker 1 from the outside. ing. The arc extinguishing device 42 is arranged adjacent to the fixed contact 61, and the elastically deformable dust barrier 43 is arranged near a specific opening provided in the case 10. Note that the dust barrier 43 can be deformed when the internal pressure of the case 10 increases due to the occurrence of an arc, and can discharge arc gas etc. from an adjacent opening.

Further, the case 10 of the embodiment is configured by combining a base 11 and a cover 12. Many of the parts housed in the base 11 are covered by the cover 12 and are normally inaccessible. There are various parts included in the circuit breaker 1, and examples include a crossbar 44, a spring 45, a handle 46, a bimetal, a trip device, and a trigger lever.

By moving downward, the crossbar 44 can press down the movable contact 50 and bring the movable contact 51 into contact with the fixed contact 61, and by moving upward, the crossbar 44 can release the pressing of the movable contact 50 and move the movable contact 50 downward. Contact 51 can be separated from fixed contact 61. The spring 45 housed inside the circuit breaker 1 can bias the movable contact 50 upward and help move the movable contact 51 away from the fixed contact 61 when the crossbar 44 moves upward. can.

The handle 46 allows the crossbar 44 to be moved upward or downward from outside the case 10. Bimetals are used to detect overcurrent and perform trip operations. The trip device can perform a trip operation using a signal from a leakage board that detects leakage current. The trigger lever can turn off the handle 46 and move the crossbar 44 upward by a trip operation using a bimetal or a trip device.

By the way, the fixed contactor 60 of the embodiment is provided on the power supply side of the circuit breaker 1, and extends downward from the first surface 60a to which the terminal screw 70 is connected and the inner end of the first surface 60a. a second surface 60b formed by bending the second surface 60b, and a third surface extending from the end of the second surface 60b substantially parallel to the first surface 60a and away from the first surface 60a. It has a surface 60c. Furthermore, a fourth surface 60d is provided that extends downward from the end of the first surface 60a opposite to the second surface 60b and is substantially parallel to the second surface 60b. (See Figure 5).

An arc gas exhaust space Ea is provided below the first surface 60a, and a nut 41 screwed into the terminal screw 70 is housed in this portion. Note that a vent hole 64 is provided on the second surface 60b to exhaust the arc gas into the exhaust space Ea. A fixed contact 61 is provided on the third surface 60c. Further, the fourth surface 60d is inserted into the base 11 to prevent the fixed contact 60 from shifting (see FIG. 3).

The arc extinguishing device 42 of the embodiment includes a plurality of grids 42a arranged at intervals and a holding frame 42b that holds the grids, and includes a second surface 60b of a fixed contact 60 and a fixed contact 61. placed between. In addition, holes 42c are formed in the holding frame 42b at positions corresponding to the ventilation holes 64 formed on the second surface 60b of the fixed contact 60, and the arc gas flows through the holes 42c and the ventilation holes 64 of the arc extinguishing device 42. It can pass through and move to the exhaust space Ea.

The dust barrier 43 of the embodiment is arranged between the second surface 60b of the fixed contact 60 and the arc extinguishing device 42. A hole 43a is formed in this dust barrier 43 at a position corresponding to a vent hole 64 formed on the second surface 60b of the fixed contact 60, and the arc gas flows through the hole 42c of the arc extinguisher 42 and the dust barrier. It can pass through the hole 43a of 43 and the vent 64 and move to the exhaust space Ea.

The base 11 of the embodiment is provided with an outer exhaust port 14 at the end of the base 11 on the power supply side for exhausting arc gas from the exhaust space Ea to the outside. Therefore, in the embodiment, the arc gas generated when the movable contact 51 and the fixed contact 61 are separated is removed from the hole 42c of the arc extinguisher 42, the hole 43a of the dust barrier 43, the vent 64, the exhaust space Ea, and the outer exhaust port 14. It can be passed in sequence and exhausted to the outside of the circuit breaker 1.

In the embodiment, an exhaust space Ea is provided below the terminal screw hole 62 of the fixed contact 60. In this exhaust space Ea, a screw protection portion is provided to prevent the terminal screw 70 from becoming difficult to remove due to exposure of the lower end side of the threaded portion 71 of the terminal screw 70 to arc gas. The screw protector is preferably provided so as to be located between the terminal screw 70 and the second surface 60b of the fixed contact 60. In particular, the fixed contact 60 is provided with a vent 64 that serves as a path for arc gas from the fixed contact 61 to the exhaust space Ea, and the screw protector provided in the exhaust space Ea is positioned between the terminal screw 70 and the vent 64. It is preferable to configure it so that

Incidentally, since it is necessary to exhaust the arc gas to the outside through the outer exhaust port 14, the vent 64 formed on the second surface 60b of the fixed contact 60 is closed, and the arc gas flows from the vent 64 to the exhaust space Ea. It is not preferable to provide a screw protector to prevent the gas from being exhausted. In addition, in such an aspect, the screw protection part is not provided in the exhaust space Ea.

In the example shown in FIG. 1, the arc gas passes through the hole 42c of the arc extinguishing device 42, the hole 43a of the dust barrier 43, the vent 64, the exhaust space Ea, and the outer exhaust port 14 in this order, and then the circuit breaker The screw protection portion is arranged so that the lower side of the threaded portion 71 of the terminal screw 70 is not exposed to arc gas while allowing exhaust to the outside of the terminal screw 70. Therefore, it is preferable that the screw protector is capable of changing the course of the arc gas.

By the way, in the case of a circuit breaker 1 in which the heights of the terminal screws 70 of adjacent poles are different, such as the example shown in FIG. A screw protector may be provided in the exhaust space Ea. A screw protector may or may not be provided in the exhaust space Ea of the pole in which the terminal screw 70 is located at a higher position than the adjacent terminal screw 70.

This is because if the lower end side of the threaded portion 71 of the terminal screw 70 located in the exhaust space Ea is not exposed to the arc gas, it is unlikely that flying objects will adhere to the threaded portion 71. In other words, if the threaded portion 71 of the terminal screw 70 is placed at a position sufficiently higher than the ventilation port 64 or the outer exhaust port 14, it is less likely to be exposed to arc gas, so there is no need to provide a screw protection portion. There are cases.

Therefore, the circuit breaker includes a movable contact 50 having a movable contact 51, a fixed contact 60 having a fixed contact 61 and a terminal screw hole 62, and a plurality of terminal screws 70 inserted into the terminal screw hole 62. 1, the adjacent terminal screw holes 62 are arranged at different heights, and the exhaust space Ea for exhausting the arc gas generated when the movable contact 51 separates from the fixed contact 61 is arranged at a lower position. It is preferable that the circuit breaker 1 is provided with a screw protection part provided below the terminal screw hole 62 and protecting the lower end side of the terminal screw 70 from arc gas in the exhaust space Ea.

From here, examples of different aspects of the screw protector will be explained. First, a case will be described in which a screw protection member 81 serving as a screw protection section is provided separately from the case 10. In the examples shown in FIGS. 2 to 6, the screw protection member 81 is constituted by a plate-like member, but the shape etc. need not be the same as in such examples. In this example, the screw protection member 81 is inserted from above into a groove provided in the base 11, and assembled so that the nut 41 and the first surface 60a of the fixed contact 60 are located above the screw protection member 81. At this time, it is preferable to provide the screw protection member 81 so as to be located between the lower end side of the threaded portion 71 of the terminal screw 70 and the second surface 60b of the fixed contact 60.

In the example shown in FIGS. 2 to 4, the path of the arc gas is changed to the left, right, and below the threaded portion 71 of the terminal screw 70 due to the presence of the screw protection member 81.

By the way, when the terminal screw 70 is tightened in a state where no electric wire is connected to the terminal portion, the threaded portion 71 of the terminal screw 70 is in a state of protruding the most into the exhaust space Ea. In this way, when the threaded portion 71 of the terminal screw 70 is most protruded into the exhaust space Ea, the vertical length of the screw protector is longer than the vertical length of the threaded portion 71 of the terminal screw 70 that protrudes downward from the nut 41. It is preferable to increase the length of .

The length of the screw protection part in the left-right direction may be larger than the length of the vent hole 64 in the left-right direction, or the length of the threaded part 71 of the terminal screw 70 in the left-right direction. It is preferable that the length of the screw protection portion in the left-right direction is longer than the longer length of the left-right direction of the vent hole 64 and the left-right direction of the threaded portion 71 of the terminal screw 70. Further, it is preferable that the screw protection portion has a larger surface in the left-right direction than the threaded portion 71 of the terminal screw 70 that projects downwardly from the nut 41.

In any case, the length of the screw protection part in the vertical direction and the length in the left and right direction are such that when the arc gas changes its course by the screw protection part and passes through the exhaust space Ea, most of the arc gas is connected to the terminal screw 70. It is preferable to be configured so as to avoid the lower end side of the portion 71 and pass through.

Note that it is preferable that the nut 41 and the screw protection member 81 are always in contact with each other in order to prevent arc gas from passing between the nut 41 and the screw protection member 81. However, there is no problem even if there is a gap between the nut 41 and the screw protection member 81 due to assembly errors.

Next, an example in which the screw protector is provided integrally with the base 11 will be explained. In the example shown in FIGS. 7 and 8, the screw protection protrusion 83 that protrudes upward is formed on the base 11, but the screw protection protrusion 83 may protrude from either the left or right direction.

At this time, it is preferable to provide the screw protection projection 83 so as to be located between the lower end side of the threaded portion 71 of the terminal screw 70 and the second surface 60b of the fixed contact 60. Further, in FIGS. 7 and 8, regarding the screw protection protrusion 83, the surface facing the second surface 60b of the fixed contact 60 is configured such that both left and right ends are separated from the second surface 60b. This allows gas to be easily discharged from the left and right sides.

In the example shown in FIGS. 7 and 8, the screw protection protrusion 83 has a sloped surface that faces the second surface 60b of the fixed contact 60. It may take a different form, such as Note that, in consideration of the discharge path, etc., one of the left and right ends may be configured to be separated from the second surface 60b. These also apply to the screw protection member 81.

Further, in the example shown in FIGS. 7 and 8, the screw protection protrusion 83 is arranged so as to create a gap between the screw protection protrusion 83 and the second surface 60b of the fixed contact 60; When the vent hole 64 is relatively large, the screw protection protrusion 83 and the second surface 60b of the fixed contact 60 may be arranged so as to be in contact with each other. This also applies to the screw protection member 81.

The screw protection protrusion 83 in this example changes the path of the arc gas to the left and right of the threaded portion 71 of the terminal screw 70. Note that it is preferable that the upper end of the screw protection protrusion 83 be provided so as to be in contact with the nut 41 or to be located at a location with a slight space between the nut 41 and the nut 41 . Further, it is preferable that the left and right ends of the screw protection protrusion 83 form inclined surfaces in order to facilitate guiding the arc gas in the left and right direction.

Next, a case where the nut 41 functions as a screw protector will be explained. In the example shown in FIG. 9, one nut 41 covers the lower end of the threaded portion 71 of the terminal screw 70. However, a plurality of nuts 41 may be used to cover the lower end of the threaded portion 71.

Note that the length in the vertical direction of the nut 41 disposed in the exhaust space Ea and screwed into the terminal screw 70 is approximately the same as or longer than the length in the vertical direction of the threaded portion 71 of the terminal screw 70 located in the exhaust space Ea. It is preferable to make it long. That is, it is preferable to use the nut 41 with a length that can cover the entire threaded portion 71 of the terminal screw 70 located in the exhaust space Ea when viewed from the side. By using such a nut 41 as a screw protector, the course of the arc gas can be changed to the left, right, and below the threaded portion 71 of the terminal screw 70.

Although the present invention has been described above using the embodiments as examples, the present invention is not limited to the above embodiments, and can be modified in various ways.

1 Circuit breaker 41 Nut 50 Movable contact 51 Movable contact 60 Fixed contact 61 Fixed contact 62 Terminal screw hole 64 Ventilation port 70 Terminal screw 71 Thread part

Claims (4)

A movable contact having a movable contact, a fixed contact having a fixed contact and a terminal screw hole, a terminal screw inserted into the terminal screw hole, and for exhausting arc gas generated when the movable contact separates from the fixed contact. A circuit breaker comprising an exhaust space,
A circuit breaker with a screw protector installed in the exhaust space below the terminal screw hole to protect the lower end of the terminal screw from arc gas. The fixed contact is provided with a vent that serves as a path for arc gas from the fixed contact to the exhaust space.
The circuit breaker according to claim 1, wherein the screw protector provided in the exhaust space is located between the terminal screw and the vent. The exhaust space is equipped with a nut that can secure the electric wire to the fixed contact by screwing into the terminal screw.
3. The circuit breaker according to claim 2, wherein the screw protection portion has a surface larger in the left-right direction than the threaded portion of the terminal screw protruding downward from the nut. A circuit breaker comprising a movable contact having a movable contact, a fixed contact having a fixed contact and a terminal screw hole, and a plurality of terminal screws inserted into the terminal screw hole,
Adjacent terminal screw holes are arranged at different heights,
An exhaust space for exhausting the arc gas generated when the movable contact separates from the fixed contact is provided below the terminal screw hole located at a low position, and a screw is installed in the exhaust space to protect the lower end side of the terminal screw from the arc gas. A circuit breaker with a protective section.