JP2007257906A - Circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit breaker of two-point cut-off type in which long life of contacts by suppressing abnormal wear of contacts due to arc caused between the fixed and movable contacts at the time of current cut-off and prevention of contact failure between the contacts in closed circuit state are realized. <P>SOLUTION: The circuit breaker of two-point cut-off type has a contact mechanism of current breaking part in which a first and a second fixed contactors 1, 2 arranged in parallel right and left, a rotating type bridging form movable contactor 3 in which the movable contacts 3a, 3b opposed to the fixed contacts 1a, 2a adhered at the tip of each fixed contactor are fixed at the tip of an arm of U-shape, and an arc extinguishing device are combined to these. Arc runners 1b, 2b which extend toward the arc extinguishing device are provided at the tip of the fixed contactors 1, 2, and arc runners 6 which hang over to right and left sideways from the outer side face of the tip of the U-shape arm are provided at the movable contactor 3. When the current is cut off, the arc generated between the first and the second fixed and movable contacts is displaced from the fixed and movable contacts to the arc runners utilizing electromagnetic repulsive force, and thereby, abnormal wear such as the one-side wear of the contacts and contact failure between the contacts due to the abnormal wear are prevented. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  The first and second fixed contacts in which the current interrupting parts of the head circuit breaker are arranged side by side parallel to each other, and the movable contact facing the fixed contact fixed to the tip of each fixed contact 2. Description of the Related Art A two-point circuit breaker is known that includes a pivoting bridge-type movable contact fixed to the tip and a grid-type arc extinguishing device that is disposed in front of the movable contact (for example, Patent Document 1).

  Next, FIG. 7 shows a conventional structure of the current interrupting portion of the above-described two-point circuit breaker. In the figure, 1 is a first fixed contact connected to the power supply side terminal, 2 is a second fixed contact leading to the load side, 1a and 2a are fixed contacts fixed to the tips of the fixed contacts 1 and 2, and 3 A pivoting bridge-shaped movable contact 4 provided with movable contacts 3a, 3b facing the fixed contacts 1a, 2a at the tip of the U-shaped arm, 4 is left and right to correspond to the fixed contacts 1, 2 individually. The grid type arc extinguishing device divided into two sets and arranged in front of the movable contact 3, 4 a is a grid (magnetic plate) vertically arranged between the left and right side walls of the arc extinguishing device 4, and 5 is a rotation support of the movable contact 3. The movable contact 3 is linked to an opening / closing mechanism (not shown). Reference numerals 1b and 2b denote arc runners extending from the tips of the stationary contacts 1 and 2 toward the arc extinguishing device 4.

With the above configuration, when the circuit breaker trips due to overcurrent and the movable contact 3 opens, the first and second fixed contacts 1, 2 and the movable contact 3 are connected as shown in FIG. The arc arc generated between the fixed / movable contacts is extended with the rotation of the movable contact 3, and the arc base point on the side of the fixed contact receiving the electromagnetic force is changed from the fixed contacts 1a, 2a to the arc runners 1b, 2b. Is moved to the position I to II shown in the figure, and is divided by the grid 4a of the arc extinguishing device 4, the arc voltage is rapidly increased, and a cooling effect is further added. As is well known, the arc disappears and the current limiting is interrupted.
Japanese Patent Laid-Open No. 11-273536 (FIGS. 1 and 3)

  By the way, in the structure of the above-described two-point current interrupting unit, the contact of the movable contact becomes uneven with the repeated operation of current interrupting. For this reason, poor contact between the fixed / movable contacts at the closed position. Cause problems.

  That is, as shown in FIG. 9 (a), the direction of the arc current i generated between the contacts of the fixed contacts 1, 2 and the movable contact 3 is opposite to the left and right, and the fixed contact 1a / Electromagnetic forces F that repel each other act on the arc generated between the movable contacts 3a and the arc generated between the fixed contacts 2a / movable contacts 3b. As a result, the arc base point moves in the opposite direction from the center of the movable contacts 3a and 3b to the left and right as shown in FIG. 9B.

  On the other hand, when the current is interrupted, a part of the movable contacts 3a and 3b is melted and evaporated by the arc energy and is consumed. As shown in FIG. 9B, the arc generated at the movable contacts 3a and 3b is contacted. If the surfaces of the contacts are moved in opposite directions, the contact wear range is biased to the left and right, and the contact surfaces are reduced as shown in the figure. This will cause abnormal heat generation during energization and problems with welding between contacts. On the other hand, since the arc base point quickly shifts from the fixed contacts 1a and 2a to the arc runners 1b and 2b on the fixed contact 1 and 2 side, the abnormal wear of the movable contacts 3a and 3b hardly occurs.

  Although the type is different from the above-mentioned two-point circuit breaker, the movable contact facing the fixed contact is divided into two pieces and juxtaposed on the left and right, and a high melting point is provided between the movable contacts. An arc horn made of a material is inserted, and the arc generated at each contact of the movable contact at the time of current interruption is transferred from the contact to the arc horn to suppress the consumption of the movable contact. It is disclosed in Japanese Patent No. 149855. However, in this method, the arc current generated between the fixed / movable contacts flows in the same direction, and electromagnetic force acts to draw the left and right arcs together. Not applicable.

  Therefore, the object of the present invention is to prevent the abnormal wear of the contact as described in FIG. 9B and to extend the life of the contact and close the circuit breaker shown in FIG. An object of the present invention is to provide an improved circuit breaker so as to improve the breaking performance together with prevention of contact failure between contacts in a pole state.

In order to achieve the above object, the first and second fixed contacts having current interrupting portions arranged side by side parallel to each other, and a movable contact facing the fixed contact fixed to the tip of each fixed contact Two sets of left and right, which are arranged opposite to each other in front of the opening movement path of the movable contact corresponding to the rotary bridge movable contact fixed to the arm tip and the first and second fixed contacts, respectively. In the circuit breaker of the two-point cutting method consisting of a grid type arc extinguishing device,
In the first invention, an arc runner extending toward the arc extinguishing device is provided at the distal end of the fixed contact, and the arc runner that projects from the outer surface of the distal end of the U-shaped arm to the left and right sides of the movable contact And an arc generated between the fixed / movable contacts when the current is interrupted is configured to be fixed and transferred from the movable contact to the arc runner (Claim 1), preferably a U-shaped arm of the movable contact The arc runner provided on the outer surface of the horn is formed with a horn portion that protrudes from its tip toward the arc extinguishing device.

According to the second aspect of the present invention, the top of the grid-type arc extinguishing device provided in the current interrupting unit is positioned close to the arm tip of the movable contact in accordance with the opening terminal position of the movable contact. An opposing ceiling grid is additionally provided (Claim 3), and the ceiling grid can be specifically configured in the following manner.
(1) Protrusions extending toward the tip of the arm of the movable contact are formed on the edge of the ceiling grid.
(2) The ceiling grid is constituted by a common grid that straddles two sets of left and right arc extinguishing devices (claim 5).
(3) An arc runner extending from the outer surface to the left and right sides is provided at the arm tip of the movable contact, and the common grid arranged on the top of the arc extinguishing chamber extends from the left and right ends toward the arc runner. An existing protrusion is formed (claim 6).

  By configuring the current interrupting part of the circuit breaker as described above, the following effects can be obtained.

  First, in the first invention, an arc runner is provided on the U-shaped arm of the movable contact so as to project laterally from the outer surface of the bifurcated tip. The generated arc receives the electromagnetic repulsive force and quickly shifts from the fixed and movable contacts to the arc runner. Thereby, the abnormal consumption (bias consumption) of the movable contact described in FIG. 9B can be prevented, and the contact failure between the contacts in the closed state can be prevented. In addition, by forming a horn part that extends toward the arc extinguishing device on the arc runner attached to the movable contact, the arc transferred from the movable contact to the arc runner during the opening operation is transferred to the horn part. From here, it can be extended to the arc extinguishing device, and the interruption performance is further improved.

  In addition, according to the second invention, by providing an additional ceiling grid at the top of the arc extinguishing device, the tip of the arm of the movable contact that has been moved to the open position by the breaking operation of the ceiling grid, Proximity to face each other. Therefore, on the movable contact side, the base point of the arc shifts from the contact surface to the tip end side of the arm of the movable contact, and is displaced between this and the ceiling grid that is in close proximity.

  As a result, the abnormal wear of the movable contact is suppressed as in the first aspect of the invention, and at the same time, the arc is cut off by the ceiling grid added to the arc extinguishing device, and the arc disappears early. In addition, by forming a protrusion on the ceiling grid that extends toward the arm tip of the movable contactor or the arc runner attached to the side of the arm tip, arc dislocation from the movable contact to the ceiling grid is prevented. Performed smoothly. Furthermore, by using this ceiling grid as a common grid that spans two sets of arc extinguishing devices arranged side by side, the number of parts and the number of assembly steps can be reduced.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on the examples shown in FIGS. In the drawings of the embodiments, members corresponding to those in FIGS. 7 and 8 are denoted by the same reference numerals and description thereof is omitted.

      First, an embodiment corresponding to claim 1 of the present invention will be described with reference to FIGS. The current interrupting portion of the illustrated embodiment is basically the same as the conventional structure shown in FIG. 7, but the movable contact 3 has arc runners 6 corresponding to the movable contacts 3a and 3b, respectively. It is additionally equipped at the tip. This arc runner 6 is an L-shaped plate made of a refractory metal material, and the left and right outer surfaces (right movable contact 3a on the right side) of the U-shaped arm so that a part of the plate surface overlaps the side surface of the movable contacts 3a and 3b. Are arranged on the right outer surface of the arm and on the left outer surface of the arm with respect to the left movable contact 3b.

  With the above configuration, when the movable contact 3 is opened when the current is interrupted, the arc generated between the left and right fixed / movable contacts in the course of the opening operation as shown in FIG. The arc base points move from the movable contacts 3a and 3b to the arc runner 6 and extend forward on the movable contact side. On the fixed contact side, the arc moves from the fixed contacts 1a, 2a to the arc runners 1b, 2b extending toward the arc extinguishing device and extends, and as described in FIG. 8, the arc extinguishing of the arc extinguishing device is performed. The arc disappears due to the action.

  As a result, the occurrence of abnormal consumption of the movable contacts 3a and 3b (reduction of the contacts) as shown in FIG. 9B is suppressed, and contact failure between the contacts in the closed state can be prevented.

  FIG. 2 is a configuration diagram of an embodiment corresponding to claim 2 of the present invention, which is a further development of the embodiment 1, and an arc extinguishing device (not shown) disposed in front of the movable contact 3 on the arc runner 6. The horn part 6a which protrudes toward () is formed.

  With this configuration, the arc transferred from the movable contacts 3a, 3b to the arc runner 6 during the opening operation when the current is interrupted moves to the horn portion 6a so as to be separated from the movable contacts 3a, 3b. It extends inward (see FIG. 8) to receive the grid division and cooling action.

  Next, an embodiment corresponding to claims 3 and 4 of the present invention is shown in FIGS. In this embodiment, the grid-type arc extinguishing device 4 disposed in front of the opening moving path of the movable contact 3 faces the tip of the arm of the movable contact 3 that has moved to the opening position at the top. In addition, a ceiling grid 4b is additionally provided, and a projection 4c extending from the rear edge of the ceiling grid 4b toward the arm tip of the movable contact 3 is formed on the ceiling grid 4b. Others are the same as the conventional structure of FIG.

  With the above configuration, when the movable contact 3 opened at the time of current interruption is rotated to the open end position in FIG. 4, the tip of the U-shaped arm of the movable contact 3 is the protrusion of the ceiling grid 4b at this position. 4c comes close to each other in the vertical direction. Thereby, when the arc generated between the fixed / movable contacts and pushed inward of the arc extinguishing device 4 is extended from the position II to the position III in FIG. The extending arc is transferred to the protrusion 4c of the ceiling grid 4b facing the arm tip of the movable contact 3, and is divided between the grids arranged vertically. Thereby, abnormal wear of the movable contacts 3a and 3b is avoided, and at the same time, the arc disappears early due to the division and cooling effect of the grid including the ceiling grid 4b added to the arc extinguishing device 4, and the interruption performance is improved.

  5 and 6 show an applied embodiment of the third embodiment corresponding to claims 5 and 6 of the present invention. In this embodiment, two sets of arc-extinguishing devices 4 arranged in front of the movable contact 3 in parallel to the left and right so as to individually correspond to the first and second fixed contacts 1, 2 are implemented. A common grid 4 d corresponding to the ceiling grid 4 b of Example 3 is disposed across the tops of the two sets of arc extinguishing devices 4. The movable contact 3 is provided with the arc runner 6 with a horn described in the second embodiment above on the outer surface of the arm tip, and the common grid so as to face the horn 6a of the arc runner 6 in close proximity. Protrusions 4e extending from the left and right ends of 4d are formed.

  According to the above configuration, in addition to the common grid 4d functioning in the same manner as the ceiling grid 4b in the third embodiment, the arc shift function by the arc runner 3 attached to the movable contact 3 is also exhibited at the same time. In addition to the effect of preventing abnormal wear of the contacts 3a, 3b, the breaking performance is further improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration and operation explanatory diagram of a two-point cutting type current interrupting unit according to Embodiment 1 of the present invention, where (a) is a perspective view showing the structure of a contact mechanism, and (b) is between fixed / movable contacts during opening operation. Schematic showing the behavior of the arc generated in The perspective view showing the structure of the contact mechanism concerning Example 2 of this invention. The perspective view of the electric current interruption part concerning Example 3 of this invention. Fig. 3 shows the transition of the behavior of arc generated between fixed / movable contacts during opening operation. The perspective view of the electric current interruption part concerning Example 4 of this invention. Fig. 5 shows the transition of the behavior of the arc generated between the fixed and movable contacts during the opening operation. The perspective view showing the assembly structure of the conventional electric current interruption part in the circuit breaker of a two-point cutting system Fig. 7 shows the transition of the behavior of the arc generated between the fixed and movable contacts during the opening operation in Fig. 7. FIGS. 8A and 8B are schematic views of the behavior transition of the arc in FIG. 8 as viewed from the front side of the contact mechanism, in which FIGS. Figure representing

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st stationary contact 2 2nd stationary contact 1a, 2a Fixed contact 1b, 2b Arc runner 3 Movable contact 3a, 3b Movable contact 4 Arc extinguishing device 4a Grid 4b Ceiling grid 4c, 4e Protruding part 4d Common grid 6 Arc Runner 6a Horn

Claims (6)

The first and second fixed contacts arranged side by side in parallel in the left and right direction, and the movable contact that faces the fixed contact fixed to the tip of each fixed contact is fixed to the tip of the U-shaped arm. Bridge-type movable contactors, and two sets of left and right grid-type arc extinguishing devices arranged in front of the opening movement path of the movable contacts corresponding to the first and second fixed contacts, respectively. In the two-point circuit breaker
An arc runner that extends toward the arc extinguishing device is provided at the tip of the fixed contact, and an arc runner that protrudes from the outer side of the tip of the U-shaped arm to the left and right sides is provided on the movable contact. A circuit breaker characterized in that an arc generated between fixed / movable contacts is fixed and transferred from the movable contact to the arc runner. 2. The circuit breaker according to claim 1, wherein a horn portion protruding from the tip of the arc runner toward the arc extinguishing device is formed on the arc runner provided on the outer surface of the movable contact. The first and second fixed contacts arranged side by side in parallel in the left and right direction, and the movable contact that faces the fixed contact fixed to the tip of each fixed contact is fixed to the tip of the U-shaped arm. Bridge-type movable contactors, and two sets of left and right grid-type arc extinguishing devices arranged in front of the opening movement path of the movable contacts corresponding to the first and second fixed contacts, respectively. In the two-point circuit breaker
A circuit breaker characterized in that a ceiling grid is provided on the top of the arc extinguishing device so as to be close to the tip of the arm of the movable contact in accordance with the opening terminal position of the movable contact. 4. The circuit breaker according to claim 3, wherein a protrusion extending toward the arm tip of the movable contact is formed on an edge of the ceiling grid. 4. The circuit breaker according to claim 3, wherein the ceiling grid is a common grid straddling two sets of left and right arc extinguishing devices. 6. The circuit breaker according to claim 5, wherein an arc runner extending from the outer surface to the left and right sides is provided at the arm tip of the movable contact, and the common grid disposed on the top of the arc extinguishing chamber has its left and right ends. The circuit breaker characterized by forming the protrusion part extended toward the said arc runner from.

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