JP7187272B2 - circuit breaker - Google Patents

Description

The present disclosure relates to circuit breakers.

A circuit breaker is a device used to break a circuit when an overload current or short-circuit current flows in an electric circuit. Patent Literature 1 listed below discloses that a circuit breaker separates a fixed contact provided on the power supply side from a movable contact provided on the load side as a method of circuit breaking.

JP 2016-33892 A

When a short-circuit current flows through the circuit due to an electric leakage or the like, a large current flows through the connecting portion between the fixed contact and the movable contact. A circuit breaker operates to separate a fixed contact and a movable contact in order to stop current flow between the contacts. In the process of separating the two contacts, the air between the fixed contact and the movable contact causes arcing. Hereinafter, in this specification, the gas that is causing the arc discharge is called arc gas.

The arc gas is in a high-temperature, high-pressure plasma state. The arc gas generated between both contacts gives a large amount of heat to the parts inside the circuit breaker.

An object of the present disclosure is to provide a circuit breaker that reduces the thermal effects of arc gas generated when a short-circuit current flows.

A circuit breaker according to the present disclosure includes a fixed contact provided with a fixed contact and attached to an attachment portion of a base, a movable contact provided with a movable contact that moves to contact or separate from the fixed contact, and a movable a mechanism for driving the movable contact so that the contact transitions between a conducting state in which the contact contacts the fixed contact and a non-conducting state in which the contact does not contact the stationary contact, the mechanism comprising a separator holding the movable contact; a contact pressure spring for generating contact pressure between the movable contact and the fixed contact, the contact pressure spring having an upper end in contact with the lower surface of the movable contact and a lower end provided on the mounting portion. It is installed in a state of being inserted into the recess. The circuit breaker is further provided with a shielding portion interposed between the fixed contact and the contact pressure spring in a non-conducting state , and the shielding portion is slanted from the contact pressure spring side toward the fixed contact side. It has an obliquely extending portion that slopes upward, and a shield attachment portion that is arranged on the attachment portion while being sandwiched between the attachment portion and the separator from above and below.

The circuit breaker has a shielding portion arranged between the stationary contact and at least a portion of the mechanical portion in a non-conducting state. In the conducting state, when a short circuit current flows through the circuit breaker, the movable contact moves to the non-conducting state. At this time, arc gas is generated between the movable contact and the fixed contact. The generated arc gas diffuses radially. Since the shielding portion is provided at a position that blocks the arc gas flowing from the fixed contact to the mechanical portion, the thermal influence of the arc gas on the mechanical portion is suppressed.

In addition , since the shielding portion is interposed between the fixed contact and the contact pressure spring in a non-conducting state in which arc gas is generated, the thermal influence of the arc gas on the contact pressure spring is suppressed. By suppressing the thermal effect on the contact pressure spring, it is possible to suppress fluctuations in the contact pressure generated by the contact pressure spring.

In the present disclosure, it is also preferable that the posture of the shielding portion changes between the conducting state and the non-conducting state so as not to hinder contact between the fixed contact and the movable contact in the conducting state.

In this preferred embodiment, the shielding portion changes its posture between the conducting state and the non-conducting state. It becomes a posture that hinders contact with the contact. Such a posture change of the shielding part can both suppress the heat effect of the arc gas and ensure the continuity.

In the present disclosure, it is also preferable that the posture of the shielding section changes in conjunction with driving of the movable contact.

When the movable contact is driven, it transitions between the conducting state and the non-conducting state. In this preferred embodiment, the attitude of the shielding portion changes in conjunction with the driving of the movable contact. It is possible to realize the posture change of the shielding part.

In the present disclosure, it is also preferable that the posture of the shielding section changes when the movable contact comes into contact with the shielding section.

In this preferred aspect, the posture of the shielding portion can be changed in conjunction with the movement of the movable contact driven so as to transition between the conducting state in which the movable contact contacts the fixed contact and the non-conducting state in which the movable contact does not contact the fixed contact. It is possible to change the attitude of the shielding part in conjunction with the driving of the movable contact with a simple configuration.

In the present disclosure, it is also preferable that the shielding section changes its posture by contacting the movable contact and elastically deforming.

In this preferred embodiment, the shield part elastically deformed in contact with the movable contact can be restored to its original shape by driving the movable contact. Posture change can be realized by a simple means of contact with a contactor.

In the present disclosure, it is also preferable that the shielding portion is inclined so that the end portion on the side of the fixed contact is higher than the end portion on the side of the mechanism portion.

In this preferred embodiment, the end on the fixed contact side is higher than the end on the mechanism side, so the arc gas generated on the fixed contact side deforms the end on the fixed contact side so that it is lifted. By causing such deformation, even when arc gas is generated, it is possible to reliably reduce the thermal influence on the mechanical portion side.

In the present disclosure, it is also preferable that the base is provided with a relief portion that can accommodate the shielding portion in the conductive state, and that the shielding portion is provided so as to extend from the movable contact toward the relief portion.

In this preferred embodiment, the shield extends from the movable contact toward the relief portion that can accommodate the shield. As it moves, its posture changes, and a part of it is accommodated in the relief section. The remaining portion of the shielding portion not housed in the relief portion is arranged between the stationary contact and the mechanical portion with which the movable contact is in contact, thereby ensuring that the movable contact is separated from the stationary contact when it separates from the stationary contact. It can be positioned between the mechanical part.

ADVANTAGE OF THE INVENTION According to this indication, the circuit breaker which reduces the thermal influence by the arc gas which arises when a short circuit current flows can be provided.

FIG. 1 is a cross-sectional view of the circuit breaker according to the first embodiment in a non-conducting state. FIG. 2 is a cross-sectional view of the circuit breaker according to the first embodiment in a conducting state. FIG. 3 is a cross-sectional view around the movable contact when the circuit breaker according to the second embodiment is in a non-conducting state. FIG. 4 is a cross-sectional view of the periphery of the movable contact in the conductive state of the circuit breaker according to the second embodiment.

Hereinafter, this embodiment will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same constituent elements in each drawing are denoted by the same reference numerals as much as possible, and overlapping descriptions are omitted.

A circuit breaker according to the first embodiment will be described. A configuration of a circuit breaker 10 according to the present embodiment will be described with reference to FIG. The circuit breaker 10 includes a housing 20, a power-side terminal fitting 30, a load-side terminal fitting 40, a movable contactor 50, a separator 60, a contact pressure spring 64, a handle 70, a shielding portion 80, and a magnetic tripping device 90. ing.

The housing 20 has a base 21 and a cover 22 . By assembling the base 21 and the cover 22, the housing 20 having an internal space is formed. A power supply side terminal fitting 30, a load side terminal fitting 40, a movable contactor 50, a separator 60, a contact pressure spring 64, a handle 70, a shielding portion 80, and a magnetic tripping device 90 are mounted on the base 21 at respective assembly positions. is assembled to. The cover 22 is attached to the base 21 and protects various parts provided on the base 21 from the external environment.

The housing 20 includes a first wall portion 201 , a second wall portion 202 , a third wall portion 203 and a fourth wall portion 204 . The first wall portion 201 and the second wall portion 202 are arranged to face each other. The third wall portion 203 and the fourth wall portion 204 are arranged to face each other.

When the circuit breaker 10 is attached to a mounting portion such as a base plate of a distribution board, the first wall portion 201 is arranged on the power supply side of the electric circuit, the second wall portion 202 is arranged on the load side of the electric circuit, and the second wall portion 202 is arranged on the load side of the electric circuit. The four wall portions 204 are arranged on the base plate side. The third wall portion 203 and the fourth wall portion 204 are provided so as to connect the first wall portion 201 and the second wall portion 202 .

The power supply side terminal fitting 30 is a terminal fitting to which a power supply side wiring (not shown) of an electric circuit is connected. The load-side terminal fitting 40 is a terminal fitting to which a load-side wiring (not shown) of an electric circuit is connected. The power-side terminal fittings 30 and the load-side terminal fittings 40 are provided so as to be exposed at the power-side end portion and the load-side end portion of the housing 20, respectively.

The power-side terminal fitting 30 includes a power-side terminal seat 31 , a fixed contactor 32 , and a connecting portion 33 . The power supply side terminal seat 31 constitutes a seat portion connected to the power supply side wiring. The fixed contact 32 constitutes a fixed contact portion that serves as a point of contact with the movable contact 50 . The connection portion 33 is a portion that connects the power supply side terminal seat 31 and the fixed contactor 32 . The fixed contact 32 is attached to the attachment portion 211 of the base 21 . The power supply side terminal seat 31, the fixed contactor 32, and the connection portion 33 are integrally formed of, for example, a conductive plate-shaped metal member.

The power-side terminal fitting 30 is arranged so as to extend from the first wall portion 201 of the housing 20 toward the interior of the housing 20 . A fixed contact 321 is provided on the fixed contact 32 .

The load-side terminal fitting 40 has a load-side terminal seat 41 . The load-side terminal fitting 40 is arranged so as to extend from the second wall portion 202 of the housing 20 toward the interior of the housing 20 . The load-side terminal seat 41 is provided at one end of the load-side terminal fitting 40 so as to be exposed to the outside at the second wall portion 202 . Load-side wiring (not shown) is connected to the load-side terminal seat 41 .

The circuit breaker 10 switches between a state in which the power-side terminal seat 31 and the load-side terminal seat 41 are electrically connected and a state in which they are electrically disconnected, so that the power-side wiring and the load-side wiring are switched. It is a device that can switch electrical connection with wiring.

The movable contact 50 has a movable contact 51 and a projecting portion 52 . The movable contact 50 is arranged inside the circuit breaker 10 while being held by a separator 60 which will be described later. The movable contact 51 is provided on the power supply side terminal seat 31 side of the movable contact 50 so as to be able to face the fixed contact 321 . The projecting portion 52 is provided so that the movable contact 50 faces the mounting portion 211 from the surface facing the mounting portion 211 . The projecting portion 52 is provided so as to be located closer to the load side terminal seat 41 than the power supply side terminal seat 31 .

The separator 60 has a tip portion 61 , a shaft portion 62 and an inner wall surface 63 . Separator 60 is assembled inside circuit breaker 10 . The distal end portion 61 is formed so as to come into contact with a pressing member 71, which will be described later. A shaft portion 62 is provided at one end of the separator 60 so that the separator 60 is supported by the housing 20 . The separator 60 is rotatable around a rotation axis m that is the central axis of the shaft portion 62 . The inner wall surface 63 is formed so as to contact the movable contact 50 .

A contact pressure spring 64 is arranged between the mounting portion 211 and the movable contact 50 . The contact pressure spring 64 is fitted against the protrusion 52 . The contact pressure spring 64 is kept compressed. The movable contact 50 is held by the separator 60 by the contact pressure spring 64 pressing the movable contact 50 against the inner wall surface 63 . In this embodiment, the separator 60 and the contact pressure spring 64 correspond to the mechanical section.

A handle 70 is provided to protrude from the third wall portion 203 of the housing 20 . The pressing member 71 is arranged so as to come into contact with the distal end portion 61 . A link mechanism (not shown) inside the housing 20 drives the pressing member 71 by moving the handle 70 . The pressing member 71 moves while pressing the separator 60 to drive the movable contactor 50 . When the pressing member 71 transitions from the non-conducting state to the conducting state, the pressing member 71 enters a locked state in which movement is restricted by the link mechanism inside the housing 20 .

The shielding portion 80 has an oblique extension portion 81 and a mounting portion 82 . The shielding part 80 is made of an insulating material. The shielding portion 80 is sandwiched between the mounting portion 211 and the separator 60 and arranged on the mounting portion 211 .

The obliquely extending portion 81 has an end portion 811 on the fixed contact 321 side. The obliquely extending portion 81 is inclined so that the end portion 811 is higher and the mounting portion 82 side is lower. The mounting portion 82 is provided on the side of the load-side terminal seat 41 of the shielding portion 80 . At the mounting portion 82 , the shielding portion 80 is sandwiched between the separator 60 and the mounting portion 211 . The shielding portion 80 undergoes elastic deformation, and mainly the posture of the obliquely extending portion 81 changes.

The magnetic tripping device 90 has an electromagnetic coil 91 , a movable magnetic piece 92 , an oil dashpot 93 , a yoke 94 , a spring 95 and an engaging piece 96 . A magnetic tripping device 90 is housed inside the housing 20 .

The electromagnetic coil 91 is arranged between the movable contact 50 and the load side terminal seat 41 . The electromagnetic coil 91 is electrically connected to the movable contact 50 through wiring (not shown). The electromagnetic coil 91 forms magnetism based on the current flowing from the movable contact 50 to the load side terminal seat 41 .

The movable magnetic piece 92 has one side 920 and the other side 921 . The movable magnetic piece 92 is held inside the housing 20 by a yoke 94 which will be described later. One side 920 is arranged between the electromagnetic coil 91 and the third wall portion 203 . One side 920 and the other side 921 are mechanically connected by a corner portion 922 . The other side 921 extends from the corner portion 922 along the first wall portion 201 toward the base 21 side.

The oil dashpot 93 has an end face 930 . The oil dashpot 93 is inserted into the electromagnetic coil 91 along the inner surface formed by the electromagnetic coil 91 . The oil dashpot 93 is fixed to the housing 20 by a yoke 94 which will be described later. Inside the oil dashpot 93, oil and an iron core that can move inside the oil dashpot 93 are accommodated. An end surface 930 of the oil dashpot 93 faces one side 920 .

One end of the yoke 94 is attached to the inner wall surface of the housing 20 on the third wall portion 203 side. The yoke 94 extends inside the housing 20 along the oil dashpot 93 from this mounting position. The yoke 94 supports the movable magnetic piece 92 so that it can rotate about the corner 922 . The other end of the yoke is bent toward the load side terminal seat 41 side. The yoke 94 holds an oil dashpot 93 at its other end.

The spring 95 is arranged between the other side 921 and the third wall portion 203 . The spring 95 applies an elastic force to the other side 921 so that the one side 920 is separated from the end surface 930 . Also, the spring 95 holds the other side 921 at a position away from the engaging piece 96 .

The engaging piece 96 is arranged between the movable magnetic piece 92 and the pressing member 71 . The engaging piece 96 can be displaced by being pushed by the other side 921 . When the engaging piece 96 is displaced, the locked state can be released if the pressing member 71 is in the locked state.

Next, operation of the circuit breaker 10 will be described with reference to FIGS. 1 and 2. FIG. FIG. 1 is a cross-sectional view of circuit breaker 10 in a non-conducting state. FIG. 2 is a cross-sectional view of the circuit breaker 10 in a conducting state. The operation of the circuit breaker 10 from the non-conducting state through the conducting state to the non-conducting state again will be described.

The non-conducting state and the transition from the non-conducting state to the conducting state will be described with reference to FIG. As shown in FIG. 1, in the non-conducting state, the separator 60 holds the movable contact 50 so that the fixed contact 321 and the movable contact 51 do not come into contact with each other. The elastic force of the contact pressure spring 64 acts on the separator 60 in the direction indicated by the arrow c2.

By operating the handle 70, the pressing member 71 is displaced toward the base 21 side. Displacement of the pressing member 71 presses the tip portion 61 toward the base 21 side. By pressing the tip portion 61 against the elastic force of the contact pressure spring 64, the separator 60 rotates about the rotation axis m in the direction indicated by the arrow c1.

The rotary motion of the separator 60 causes the movable contact 50 to rotate so that the movable contact 51 contacts the fixed contact 321 . The contact pressure spring 64 is compressed by the rotational movement of the movable contactor 50 .

When the movable contact 50 rotates to compress the contact pressure spring 64 , the movable contact 50 approaches the shielding portion 80 and moves while contacting the shielding portion 80 . Movable contact 50 moves to press end 811 . When the end portion 811 is pressed, the shielding portion 80 elastically deforms. Due to the elastic deformation of the shielding portion 80 , the posture of the obliquely extending portion 81 changes so as to be nearly parallel to the mounting portion 211 . Since the obliquely extending portion 81 changes its posture according to the movement of the movable contact 50 , it does not prevent the contact between the movable contact 51 and the fixed contact 321 .

The contact of the movable contact 51 with the fixed contact 321 causes the circuit breaker 10 to transition from the non-conducting state to the conducting state.

The conductive state will be described with reference to FIG. When the handle 70 is operated to the position shown in FIG. 2, the pressing member 71 is held at the position shown in FIG. The pressing member 71 is locked. Thereby, the conductive state is maintained. That is, the electric circuit between the power supply side terminal seat 31 and the load side terminal seat 41 is connected.

The contact pressure spring 64 is held in a compressed state by the movable contactor 50 . The compressed contact pressure spring 64 generates contact pressure that presses the movable contact 51 against the fixed contact 321 .

The obliquely extending portion 81 is positioned so as not to prevent contact between the movable contact 51 and the fixed contact 321 . The obliquely extending portion 81 presses the movable contact 50 at the end portion 811 .

The operation of transitioning from the conducting state to the non-conducting state will be described. Here, it is assumed that a large short-circuit current flows through the circuit breaker 10 due to a short circuit in wiring. When a short-circuit current flows, the magnetic tripping device 90 operates so as to break the electric circuit.

When an overcurrent due to a short circuit flows, the electromagnetic coil 91 instantly generates a strong magnetic field. A magnetic force is generated on the end surface 930 of the oil dashpot 93 by the electromagnetic coil 91 generating a strong magnetic field. One side 920 of the movable magnetic piece 92 is attracted to the end surface 930 by the magnetic force generated by the end surface 930 .

When the one side 920 approaches the end surface 930, the movable magnetic piece 92 rotates about the corner 922 as an axis. The other side 921 moves to the engaging piece 96 due to the rotational motion. The movement of the other side 921 brings the other side 921 into contact with the engaging piece 96 . The engaging piece 96 is pressed by the other side 921 and displaced. When the engaging piece 96 is displaced, the pressing member 71 is unlocked. The pressing member 71 whose locked state is released can move toward the third wall portion 203 .

Since the pressing member 71 is movable, the separator 60 receives elastic force from the contact pressure spring 64 and rotates. The separator 60 drives the movable contactor 50 so as to separate the fixed contact 321 and the movable contact 51 .

When the fixed contact 321 and the movable contact 51 are separated from each other, the air between the fixed contact 321 and the movable contact 51 causes arc discharge to generate arc gas.

The obliquely extending portion 81 receives a restoring force caused by elastic deformation of the shielding portion 80 . When the movable contact 50 is driven to separate the fixed contact 321 and the movable contact 51 , the obliquely extending portion 81 follows the movement of the movable contact 51 and changes its posture. The obliquely extending portion 81 starts to change its posture when the fixed contact 321 and the movable contact 51 are separated, that is, when the arc gas starts to be generated.

The attitude of the obliquely extending portion 81 changes from a nearly parallel attitude with respect to the mounting portion 211 to an increasing inclination with respect to the mounting portion 211 . By changing in this way, the obliquely extending portion 81 changes its posture while being interposed between the fixed contact 321 and the contact pressure spring 64 in the process of changing the posture.

The arc gas diffuses radially inside the housing 20 . Among the generated arc gases, those directed toward the contact pressure spring 64 are intercepted by the obliquely extending portion 81 interposed between the fixed contact 321 and the contact pressure spring 64 . Therefore, the arc gas reaching the contact pressure spring 64 is reduced.

When the circuit is interrupted, no current flows through the electromagnetic coil 91, so the magnetic force generated by the electromagnetic coil 91 also disappears. Due to the disappearance of the magnetic force, the movable magnetic piece 92, the oil dashpot 93, the spring 95, and the engaging piece 96 are brought into the state shown in FIG.

When the pressing member 71 moves to the position shown in FIG. 1 and stops moving toward the third wall portion 203, the movement or posture change of the separator 60, the movable contactor 50, and the shielding portion 80 stops. The separator 60, the movable contactor 50, and the shielding portion 80 after transitioning from the conducting state to the non-conducting state are in the state shown in FIG. Also, the handle 70 is unlocked and is in the state shown in FIG.

In the circuit breaker 10 according to the first embodiment, the contact pressure spring 64 is provided between the movable contact 50 and the base 21 and generates contact pressure between the movable contact 51 and the fixed contact 321. A shielding portion 80 having an obliquely extending portion 81 is arranged so that the obliquely extending portion 81 is interposed between the fixed contact 321 and the contact pressure spring 64 .

The obliquely extending portion 81 can block arc gas flowing from the fixed contact 321 to the contact pressure spring 64 . Since deterioration of the contact pressure spring 64 due to arc gas can be suppressed, it is possible to suppress poor conduction of the circuit breaker 10 due to insufficient contact pressure.

In the circuit breaker 10 according to the first embodiment, the posture of the obliquely extending portion 81 changes between the conducting state and the non-conducting state so as not to obstruct the contact between the fixed contact 321 and the movable contact 51 in the conducting state. As a result, arc gas can be shielded without impairing the function of the circuit breaker 10 while the obliquely extending portion 81 secures the shielding function.

In the circuit breaker 10 according to the first embodiment, the posture of the obliquely extending portion 81 changes in conjunction with the driving of the movable contactor 50 . As a result, the attitude of the obliquely extending portion 81 can be changed appropriately with respect to switching between the conducting state and the non-conducting state by driving the movable contact 50 .

In the circuit breaker 10 according to the first embodiment, the attitude of the obliquely extending portion 81 changes when the movable contactor 50 comes into contact with the obliquely extending portion 81 . As a result, the movable contact 50 is driven in the direction in which the movable contact 51 and the fixed contact 321 contact each other when the non-conducting state is changed to the conducting state. The movable contact 50 moves while pressing the obliquely extending portion 81 . Therefore, the posture of the obliquely extending portion 81 can be changed without introducing a new mechanism for changing the posture of the obliquely extending portion 81 .

In the circuit breaker 10 according to the first embodiment, the shielding portion 80 including the diagonally extending portion 81 is elastically deformed by contact with the movable contact 50, and the posture of the shielding portion 80 including the diagonally extending portion 81 is elastically deformed. Varies with force.

As a result, when the conducting state transitions to the non-conducting state, the shielding portion 80 including the obliquely extending portion 81 receives a restoring force due to elastic deformation. The obliquely extending portion 81 is interposed between the fixed contact 321 and the contact pressure spring 64 according to the movement of the movable contact 50, and can change its posture so as to block the arc gas. Therefore, the transfer of heat from the arc gas to the contact pressure spring 64 is suppressed.

In the circuit breaker 10 according to the first embodiment, the obliquely extending portion 81 is inclined so that the end portion 811 on the fixed contact 321 side is higher and the mounting portion 82 side is lower. As a result, even if the obliquely extending portion 81 receives pressure from the arc gas and the end portion 811 side is lifted, the shielding state of the arc gas can be maintained.

Next, a circuit breaker according to a second embodiment will be described with reference to FIGS. 3 and 4. FIG. Among the configurations of the circuit breaker according to the second embodiment, differences from the first embodiment will be mainly described.

The circuit breaker according to the second embodiment differs from the circuit breaker 10 according to the first embodiment in that the shielding portion 80A shown in FIG. 3 is provided and the mounting portion 211A is provided with the relief portion 212A. It is a point. The relief portion 212A is formed by cutting out a portion of the attachment portion 211A.

In the non-conducting state shown in FIG. 3, the movable contactor 50, the separator 60, the contact pressure spring 64, and the pressing member 71 are in the same state as in the first embodiment.

The shielding portion 80A has an oblique extension portion 81A and an attachment portion 82A. The shielding portion 80A is made of an insulating material. The shielding portion 80A is arranged between the movable contact 50 and the mounting portion 211A. The mounting portion 82A is arranged along the surface of the movable contact 50 on the side of the mounting portion 211A. The mounting portion 82A is formed so as not to interfere with the projecting portion 52. As shown in FIG. The obliquely extending portion 81A is arranged between the fixed contact 321 and the contact pressure spring 64 . The obliquely extending portion 81A is formed to extend from the mounting portion 82A toward the fixed contact 321 side.

Next, operation of the circuit breaker according to the second embodiment will be described. First, the transition from the non-conducting state of FIG. 3 to the conducting state of FIG. 4 will be described.

When the pressing member 71 is moved toward the attachment portion 211A by operating the handle, the separator 60 and the movable contactor 50 rotate so that the movable contact 51 and the fixed contact 321 come into contact with each other.

As the separator 60 and the movable contact 50 move, the shielding portion 80A also rotates. The obliquely extending portion 81A rotates according to the movement of the movable contact 50 to change its posture from the posture shown in FIG. 3 to the posture shown in FIG. At this time, the obliquely extending portion 81A maintains its relative posture with respect to the movable contactor 50 .

When the posture changes, part of the obliquely extending portion 81A changes its posture so as to be accommodated in the escape portion 212A. Therefore, the obliquely extending portion 81A does not come into contact with the mounting portion 211A.

The stationary contact 321 and the movable contact 51 are brought into contact with each other, and the pressing member 71 is locked, thereby completing the transition from the non-conducting state to the conducting state.

Next, the operation when the conductive state shown in FIG. 4 is changed to the non-conductive state shown in FIG. 3 will be described. When a short-circuit current flows, the circuit breaker operates to separate the fixed contact 321 and the movable contact 51 . When transitioning from the conducting state to the non-conducting state, the movable contact 50 and the separator 60 separate the fixed contact 321 and the movable contact 51 from each other. At this time, arc gas is generated between the fixed contact 321 and the movable contact 51 .

As the movable contact 50 and the separator 60 move, the posture of the shielding portion 80A changes. The obliquely extending portion 81A rotates and changes its posture. Specifically, the posture changes so that the portion housed in the escape portion 212A is interposed between the fixed contact 321 and the contact pressure spring 64. As shown in FIG. The obliquely extending portion 81A maintains a relative posture with respect to the movable contactor 50. As shown in FIG.

The arc gas diffuses radially inside the housing 20 . Among the generated arc gases, those directed toward the contact pressure spring 64 are intercepted by the obliquely extending portion 81A interposed between the fixed contact 321 and the contact pressure spring 64 . Therefore, the arc gas reaching the contact pressure spring 64 is reduced.

When the pressing member 71 moves to the position shown in FIG. 3 and stops moving, the separator 60, the movable contactor 50, and the shielding portion 80A stop moving and changing their postures. The separator 60, the movable contact 50, and the shielding portion 80A after transitioning from the conductive state to the non-conductive state are in the state shown in FIG.

The circuit breaker according to the second embodiment is provided with a relief portion 212A capable of accommodating the obliquely extending portion 81A in the conductive state. As a result, the obliquely extending portion 81A does not come into contact with the mounting portion 211A while the shielding ability of the obliquely extending portion 81A is ensured. Since the movement of the movable contactor 50 is not hindered by the obliquely extending portion 81A, the posture of the obliquely extending portion 81A can be changed so that the contact between the fixed contact 321 and the movable contact 51 is not hindered.

The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications to these specific examples by those skilled in the art are also included in the scope of the present disclosure as long as they have the features of the present disclosure. Each element included in each specific example described above and its arrangement, conditions, shape, etc. are not limited to those illustrated and can be changed as appropriate. As long as there is no technical contradiction, the combination of the elements included in the specific examples described above can be changed as appropriate.

10: Circuit breaker 21: Base 32: Fixed contact 50: Movable contact 64: Contact pressure spring 80: Shielding part

Claims (7)

A circuit breaker,
a fixed contact provided with a fixed contact and attached to the mounting portion of the base;
a movable contact provided with a movable contact that moves to contact or separate from the fixed contact;
a mechanism unit that drives the movable contact so that the movable contact transitions between a conductive state in which the movable contact contacts the fixed contact and a non-conductive state in which the movable contact does not contact the fixed contact;
The mechanism unit has a separator that holds the movable contact, and a contact pressure spring that generates contact pressure between the movable contact and the fixed contact,
The contact pressure spring is installed with its upper end in contact with the lower surface of the movable contact and its lower end inserted into a recess provided in the mounting portion,
Further, a shielding portion is provided between the fixed contact and the contact pressure spring in the non-conducting state,
The shielding portion is disposed on the mounting portion in a state sandwiched from above and below between the mounting portion and the separator and the obliquely extending portion inclined obliquely upward from the contact pressure spring side toward the fixed contact side. A circuit breaker comprising: a shielding attachment ; A circuit breaker according to claim 1, wherein
A circuit breaker according to claim 1, wherein a posture of the shielding portion changes between the conducting state and the non-conducting state so as not to inhibit contact between the fixed contact and the movable contact in the conducting state. A circuit breaker according to claim 2 ,
The circuit breaker, wherein the posture of the shielding portion changes in conjunction with driving of the movable contact. A circuit breaker according to claim 3 ,
The circuit breaker, wherein the posture of the shielding portion changes when the movable contact comes into contact with the shielding portion. A circuit breaker according to claim 4 ,
The circuit breaker, wherein the shield changes its posture by contacting the movable contact and elastically deforming. A circuit breaker according to claim 5 ,
The circuit breaker, wherein the shielding portion is inclined such that the end portion on the side of the fixed contact is higher than the end portion on the side of the mechanism portion. A circuit breaker according to claim 3 ,
The circuit breaker, wherein the base is provided with a relief portion capable of accommodating the shielding portion in the conductive state, and the shielding portion is provided so as to extend from the movable contact toward the relief portion. .

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