JP2010272482A - Circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit breaker in which a high current limiting effect is obtained as an arc is extended at the time of open circuit and damages of contacts are suppressed. <P>SOLUTION: The circuit breaker 1 is provided with a first fixed contactor 1 having a first fixed contact 21, a second fixed contactor 3 having a second fixed contact 31, a movable contactor 4 which has a first movable contact 41 opposed to the first fixed contact 21 and a second movable contact 42 opposed to the second fixed contact 31, and a first insulator 6 preventing a short circuit between the first fixed contact 21 and the movable contactor 4. The first insulator 6 has a first through-hole 61 which receives gas generated by arc AC1 between the first fixed contact 21 and the first movable contact 41 from one end opening 62 and discharges from the other end opening 63. Since the gas generated by the arc AC1 goes through the first through-hole 61 and is discharged from the other end opening 63, and assists circuit opening action of the movable contactor 4, the circuit opening speed is increased and current limiting effect is enhanced, and thereby, damages of the contacts can be suppressed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a circuit breaker for wiring circuit breakers and earth leakage circuit breakers, and more particularly to a structure of a current breaker.

  Conventionally, a circuit breaker has a function of opening and closing an electric circuit by operating an operation handle provided in the circuit breaker, that is, not only a switch function, but also an electric wire and a load device due to overcurrent etc. In order to prevent this, it plays the role of cutting off the electric circuit. When an abnormality such as overcurrent occurs, the contact is opened by a built-in spring or the like. As one of the parts for satisfying these functions of the circuit breaker, a movable contact having a movable contact that comes into contact with a fixed contact having a fixed contact in a closed state and is separated from a fixed contact in an opened state. A child. The connecting conductor connected to this movable contact is used in a small circuit breaker with a rated current of 30 to 100 A, where a copper shunt wire or a shunt made of laminated thin plates is flexible and is subject to space constraints. ing.

  However, this shunt has a problem of fatigue disconnection in the above-described opening / closing function, so that the opening / closing life has to be limited. Therefore, as one means for improving the open / close life, the movable contact and the connection conductor are brought into sliding contact, and the contact spring disposed outside the connection conductor is used to increase the contact pressure between the movable contact and the connection conductor. An energization mechanism is known. The electrical contact between the movable contact and the connecting conductor is generally called a shuntless energization mechanism because a shunt is not used.

  Further, there is known a two-point circuit breaker that is a shuntless energization mechanism and opens / closes at two points (see, for example, Patent Document 1). In such a circuit breaker, arcs generated at two points that perform opening / closing are moved to the outer periphery of the contact by electromagnetic repulsion, so that the damaged portion is concentrated and the contact is reduced. For this purpose, the magnetic plate is inserted between two points for opening / closing, to weaken the electromagnetic repulsive force and prevent the contact from being reduced. However, even in such a circuit breaker, since the contact is damaged by an arc generated at the time of opening, it is desired to increase the current limiting effect.

JP 2007-280928 A

  An object of the present invention is to solve the above problems, and to provide a circuit breaker that has a high opening speed, provides a high current limiting effect, and suppresses damage to contacts.

  In order to achieve the above object, the first aspect of the present invention provides a first fixed contact having a first fixed contact, a second fixed contact having a second fixed contact, and the first fixed contact. And a movable contact having a first movable contact facing the second movable contact and a second movable contact facing the second fixed contact and having an electric circuit portion connecting the movable contacts. A first insulator is provided between the first fixed contact and the electric circuit portion of the movable contact, and the insulator is formed by an arc between the first fixed contact and the first movable contact. The first through hole that receives the generated gas from one end opening and ejects the gas from the other end opening, and the gas that is ejected from the other end opening performs the opening operation of the movable contact. It is provided to support.

  According to a second aspect of the present invention, in the circuit breaker according to the first aspect, the circuit breaker includes a second insulator provided to face the first insulator with the first fixed contact in between. The second insulator directs the gas generated by the arc between the first fixed contact and the first movable contact toward the one end opening of the first through hole.

  According to a third aspect of the present invention, in the circuit breaker according to the first or second aspect, the first insulator is a gas generated by an arc between the second fixed contact and the second movable contact. A second through hole is received from one end opening and ejected from the other end opening, and the second through hole energizes the opening operation of the movable contact by the gas ejected from the other end opening. It is provided.

  The circuit breaker according to claim 4 is the circuit breaker according to claim 3, wherein the guide part is provided on the opposite side of the first insulator across the electric circuit part, and guides the opening / closing operation of the movable contact; A third insulator provided opposite to the guide portion across the second fixed contact, and the third insulator and the guide portion include the second fixed contact and the second insulator. The gas generated by the arc between the movable contacts is directed toward one end opening of the second through hole of the first insulator.

  According to the first aspect of the present invention, the gas generated by the arc between the first fixed contact and the first movable contact passes through the first through hole and is ejected from the other end opening to open the movable contact. Since the operation is energized, the opening speed is increased, the current limiting effect is increased, and the contact damage is suppressed.

  According to the invention of claim 2, since the gas generated by the arc between the first fixed contact and the first movable contact is directed to one end opening of the first through hole by the second insulator, from the other end opening The pressure to be ejected becomes stronger, the opening operation is further energized, and the current limiting effect is further enhanced.

  According to the invention of claim 3, the gas generated by the arc between the second fixed contact and the second movable contact passes through the second through hole and is ejected from the other end opening to open the movable contact. Since the operation is further energized, the current limiting effect is further enhanced.

  According to the invention of claim 4, since the gas generated by the arc between the second fixed contact and the second movable contact is directed to one end opening of the second through hole by the third insulator, The pressure to be ejected becomes stronger, the opening operation is further energized, and the current limiting effect is further enhanced.

The lineblock diagram of the circuit breaker concerning a 1st embodiment of the present invention. (A) is the side view at the time of closing of the circuit breaker, (b) is the side view at the time of opening of the circuit breaker. (A) is the side view at the time of closing of the circuit breaker concerning the modification of embodiment same as the above, (b) is the side view at the time of opening of the circuit breaker. (A) is a side view when the circuit breaker according to the second embodiment of the present invention is closed, and (b) is a side view when the circuit breaker is opened. (A) is a side view at the time of closing of the circuit breaker concerning the 3rd embodiment of the present invention, (b) is a side view at the time of opening of the circuit breaker.

(First embodiment)
The circuit breaker 1 which concerns on the 1st Embodiment of this invention is demonstrated with reference to FIG.1 and FIG.2 (a) (b). As shown in these drawings, the circuit breaker 1 includes a first fixed contact 2 connected to one of the commercial power source or the load device and a second fixed contact connected to the other of the commercial power source or the load device. A contact 3, a movable contact 4 that opens and closes the first fixed contact 2 and the second fixed contact 3, a housing 5 (indicated by a one-dot chain line) that covers each contact, etc. 1 insulator 6 and a guide portion 7. The first insulator 6 prevents a short circuit between the first fixed contact 2 and the movable contact 4. The guide unit 7 guides the opening / closing operation of the movable contact 4 and prevents a short circuit between the second movable contact 42 and the second fixed contact 3. In the figure, the X direction is the forward direction, and the Y direction is the horizontal direction. The circuit breaker 1 detects the current and voltage in the second fixed contact 3 by a detection unit (not shown), and when an abnormality such as an overcurrent is detected, the tripping unit (not shown) moves the movable contact. The child 4 is slid and pulled off to interrupt the electric circuit. FIG. 1 shows an open state.

  The tip of the first fixed contact 2 protrudes outward from the front surface of the housing 5, and the lateral direction of each contact or the like is surrounded by the side wall surface of the housing 5. The first fixed contact 2 and the second fixed contact 3 are provided in parallel in two upper and lower stages, the first fixed contact 2 has a first fixed contact 21 on the upper surface, The second stationary contact 3 has a second stationary contact 31 on the upper surface.

  The movable contact 4 slides up and down to perform an opening / closing operation. The movable contact 4 has an upper side, a lower side, and an electric circuit portion 43 connecting them, and a first fixed contact on the lower surface of the upper side. 21 is disposed, and a second movable contact 42 facing the second fixed contact 31 is disposed on the lower surface of the lower side. The electric circuit part 43 of the movable contact 4 includes an extended electric circuit part 43a, a parallel electric circuit part 43b, and a connecting part 43c that form a U-shape in side view. The extension electric circuit portion 43a rises upward from the upper side, the parallel electric circuit portion 43b is substantially parallel to a straight line connecting the first fixed contact 21 and the first movable contact 41 at the time of contact opening, and the connecting portion 43c is an extension electric circuit portion. 43a and parallel electric circuit part 43b are connected. The current direction in the parallel electric circuit portion 43b is opposite to the current direction from the first fixed contact 21 to the first movable contact 41 (see FIG. 2B). The movable contact 4 has arc runners 44 and 45 at the tips of the upper side and the lower side, respectively.

  The second fixed contact 3 has a second parallel electric circuit portion 33 that rises substantially parallel to a straight line connecting the second movable contact 42 and the second fixed contact 31 when the contact is opened. Yes. The current direction in the second parallel electric circuit portion 33 and the current direction from the second movable contact 42 to the second fixed contact 31 are opposite to each other (see FIG. 2B). The second stationary contact 3 has an arc runner 32 at the tip.

  The first insulator 6 is formed in an L shape by an insulating material such as nylon or PBT, for example, and is surrounded by an extended electric circuit portion 43a, a parallel electric circuit portion 43b, and a connecting portion 43c, and a first fixed contact. It is attached to a chassis (not shown) of the circuit breaker 1 so as to be positioned below the child 2. The first insulator 6 is provided so as to shield the parallel electric path portion 43 b of the movable contact 4 and its lower side from the first fixed contact 21 and the first fixed contact 2.

  Further, the first insulator 6 has a first through hole 61 for receiving and penetrating a gas generated by an arc (referred to as a first arc) AC1 between the first fixed contact 21 and the first movable contact 41. is doing. The first through hole 61 has one end opening 62 opened toward the first fixed contact 21 and the first movable contact 41 and the other end opening 63 opened toward the space formed by the connecting portion 43c. Are connected.

  The guide portion 7 is made of an insulating material such as nylon or PBT, for example, and is attached to the chassis on the opposite side of the first insulator 6 with the parallel electric path portion 43b interposed therebetween. The movable contact 4 is guided to slide up and down by the guide portion 7 and the first insulator 6.

  Next, the breaking operation of the circuit breaker 1 of the present embodiment will be described. As shown in FIG. 2A, at the time of closing, the first fixed contact 21 is in contact with the first movable contact 41, the second fixed contact 31 is in contact with the second movable contact 42, and from the commercial power source. Is supplied to the load device via the first fixed contact 2, the movable contact 4, and the second fixed contact 3. When an energization abnormality such as overcurrent occurs, the movable contact 4 is pulled upward from the first fixed contact 2 and the second fixed contact 3 as shown in FIG. To do. At this time, an arc (referred to as a second arc) AC2 between the second movable contact 42 and the second fixed contact 31 is generated together with the first arc AC1.

  At this time, the gas generated by the heat of the first arc AC1 is received by the one end opening 62, enters the first through hole 61, and is ejected from the other end opening 63 into the space formed by the connecting portion 43c. As the jet power and the pressure in the space increase, the opening operation of the movable contact 4 is energized. Since the opening of the movable contact 4 is accelerated by this biasing, the current limiting effect is enhanced, and damage to the contact is suppressed.

  Further, since the direction of the current in the first arc AC1 at the time of opening is the direction of the arrow A in the figure, and the direction of the current in the parallel circuit portion 43b is the direction of the arrow B, a magnetic field is present in the vicinity of the first arc AC1. From the front to the back. Due to this magnetic field, the first arc AC1 is subjected to a Lorentz force in the direction of arrow C and is expanded in an arc shape. Along with this, the arc voltage increases, and a high current limiting effect is obtained. Similarly, the direction of the current in the second arc AC2 at the time of opening is the direction of the arrow D, and the direction of the current in the second parallel circuit portion 33 is the direction of the arrow E, so that there is a magnetic field in the vicinity of the second arc AC2. Occurs with the paper facing from the back to the front. By this magnetic field, the second arc AC2 is subjected to a Lorentz force in the direction of arrow F and is expanded in an arc shape, the arc voltage is increased, and a high current limiting effect is obtained.

  Further, the first arc AC1 is moved to the arc runner 44 and the first stationary contact 2 by the Lorentz force, and the second arc AC2 is moved to the arc runners 45 and 32. Therefore, the damage of each contact is reduced, and the contact Poor contact is unlikely to occur. Moreover, since the 1st stationary contact 2, the 2nd stationary contact 3, and the movable contact 4 are arrange | positioned at the up-down direction, the width dimension seen from the front of the circuit breaker 1 can be made small. .

  Next, a modification of the present embodiment will be described with reference to FIGS. In this modification, the description of the configuration equivalent to that of the circuit breaker of the first embodiment is omitted. In the circuit breaker 1 according to the present modification, in addition to the configuration in the first embodiment, the first insulator 6 has a second through-hole 64 that allows gas generated by the second arc AC2 to pass therethrough. ing. The second through-hole 64 connects one end opening 65 opened toward the lower side of the movable contact 4 and the other end opening 66 opened toward the space formed by the connecting portion 43c. The gas generated by the second arc AC2 is ejected into the space formed by the connecting portion 43c through the second through hole 64, and the opening operation of the movable contact 4 is energized. In this way, the opening of the movable contact 4 is further accelerated by the energization by the gas generated by the second arc AC2, so that the current limiting effect is further enhanced.

(Second Embodiment)
A circuit breaker according to a second embodiment of the present invention will be described with reference to FIGS. The circuit breaker 1 according to the present embodiment has a second configuration for directing the diffusion direction of the gas generated by the first arc AC1 toward the one end opening 62 of the first insulator 6 in addition to the configuration in the first embodiment. An insulator 81 is provided. The second insulator 81 is provided to face the first insulator 6 with the first fixed contact 21 in between. As a result, the forward direction of the first fixed contact 21 and the first movable contact 41 is surrounded by the second insulator 81. Further, the lateral direction of the first fixed contact 21 and the first movable contact 41 is surrounded by a side wall surface of a housing (not shown). With this configuration, the gas generated by the first arc AC1 is concentrated without being scattered and travels toward the one end opening 62, so that the amount of gas passing through the first through hole 61 is increased, and the space formed by the connecting portion 43c. Since the pressure ejected into the inside becomes stronger, the opening operation of the movable contact 4 is further energized, and the current limiting effect is enhanced. Further, an insulator other than the second insulator 81 may be further provided so that the gas generated by the first arc AC <b> 1 is further directed to the one end opening 62.

(Third embodiment)
A circuit breaker according to a third embodiment of the present invention will be described with reference to FIGS. The circuit breaker 1 according to this embodiment has a configuration for directing the direction of gas generated by the second arc AC2 toward the one end opening 65 of the first insulator 6 in addition to the configuration in the modification of the first embodiment. A third insulator 82 is provided. The third insulator 82 is provided to face the guide portion 7 with the second fixed contact 31 interposed therebetween. Thereby, the front direction of the second fixed contact 31 and the second movable contact 42 is surrounded by the third insulator 82, and the rear direction is surrounded by the guide portion 7. The lateral direction of the second fixed contact 31 and the second movable contact 42 is surrounded by a side wall surface of a housing (not shown). With this configuration, the gas generated by the second arc AC2 is concentrated without being scattered and travels toward the one end opening 65, so that the amount of gas penetrating the second through hole 64 is increased, and the space formed by the connecting portion 43c. Since the pressure ejected into the inside becomes stronger, the opening operation of the movable contact 4 is further energized, and the current limiting effect is enhanced. Further, an insulator other than the third insulator 82 may be further provided so that the gas generated by the second arc AC2 is further directed toward the one end opening 65.

  In addition, this invention is not restricted to the structure of the said embodiment, A various deformation | transformation is possible in the range which does not change the meaning of invention. For example, the movable contact 4 may be formed in a flat plate shape that connects the upper side and the lower side of the contact, rather than the U-shaped electric path portion 43. However, in this configuration, the effect due to the pressure increase in the space due to the gas cannot be sufficiently expected as compared with the case where the electric circuit portion 43 is U-shaped. The second stationary contact 3 may have a shape that does not include the second parallel electric circuit portion 33 that rises upward. In this case, the current limiting effect due to the Lorentz force cannot be expected. In the third embodiment, the second insulator 81 of the second embodiment may be further provided. This further increases the current limiting effect. Further, in each embodiment, a single-pole circuit breaker is shown, but the number of poles may be plural, and when there are plural poles, the poles are partitioned by a partition plate.

DESCRIPTION OF SYMBOLS 1 Circuit breaker 2 1st stationary contact 21 1st stationary contact 3 2nd stationary contact 31 2nd stationary contact 4 Movable contact 41 1st movable contact 42 2nd movable contact 43 Electric circuit part 6 First insulator 61 First through hole 62, 65 One end opening 63, 66 Other end opening 64 Second through hole 7 Guide portion 81 Second insulator 82 Third insulator AC1 First arc (arc)
AC2 2nd arc (arc)

Claims (4)

A first fixed contact having a first fixed contact; a second fixed contact having a second fixed contact; a first movable contact facing the first fixed contact; and the second fixed contact. In a circuit breaker having a second movable contact facing the contact and a movable contact having an electric circuit portion connecting these movable contacts,
A first insulator is provided between the first fixed contact and the electric circuit portion of the movable contact,
The insulator has a first through hole that receives a gas generated by an arc between the first fixed contact and the first movable contact from one end opening and ejects the gas from the other end opening;
The circuit breaker according to claim 1, wherein the first through hole is provided so that a gas ejected from the other end opening urges the opening operation of the movable contact. A second insulator provided facing the first insulator across the first fixed contact;
2. The second insulator according to claim 1, wherein a gas generated by an arc between the first fixed contact and the first movable contact is directed toward one end opening of the first through hole. Circuit breaker as described. The first insulator has a second through hole that receives a gas generated by an arc between the second fixed contact and the second movable contact from one end opening and ejects the gas from the other end opening;
3. The circuit according to claim 1, wherein the second through hole is provided so that a gas ejected from the other end opening urges the opening operation of the movable contact. 4. Circuit breaker. A guide part provided on the opposite side of the first insulator across the electric circuit part to guide the opening and closing operation of the movable contact;
A third insulator provided opposite to the guide portion across the second fixed contact,
The third insulator and the guide portion direct the gas generated by the arc between the second fixed contact and the second movable contact toward one end opening of the second through hole of the first insulator. The circuit breaker according to claim 3.

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