JP2007115540A - Circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a stopper mechanism of a movable contactor provided in an arc-extinguishing chamber so as to enhance strength and safety of component parts by avoiding concentration of an impact load added from the movable contactor on the chamber. <P>SOLUTION: In the circuit breaker equipped with a rotating movable contactor 3 linked with a fixed contactor 2 and a switching mechanism 5 inside a chassis 1 consisting of a case 1a and a cover 1b, and an arc-extinguishing chamber 8 consisting of a box-shaped insulating frame 9 and a plurality of upper and lower steps of grid plates 10 retained in alignment inside the insulating frame along a switching movement path of the movable contactor, with tip parts of the insulating frame faced with each other in adjacency with an inner face of the cover 1b, a knocking part 11a of the movable contactor is formed in protrusion at a rear end of the grid ceiling plate 11 arranged at an uppermost step of the chamber as a stopper means for regulating an open terminal position of the movable contactor and moreover, the grid ceiling plate is locked and retained in free up-and-down movement at a tip part of the insulating frame. Then, a rear face of the movable contactor moving to open at the breaking operation is made in contact with a plate face of the knocking part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a circuit breaker, for example, for a circuit breaker for wiring, and more specifically, a stopper that is provided in an arc extinguishing chamber of a circuit breaker and regulates the opening end position of a movable contact that opens during a breaking operation. It relates to the structure of the mechanism.

  As is well known, when an excessive current such as a short circuit current flows in the main circuit, the circuit breaker for wiring uses an electromagnetic repulsive force that acts between the fixed contact and the movable contact. An arc generated between the fixed and movable contacts is driven from the closed position to the open position, and an arc extinguishing chamber with a grid plate (diaion grid) is placed on the open / close movement path of the movable contact. Is pushed into the arc extinguishing chamber and the current limiting is interrupted by the slit effect of the grid plate.

Further, in this circuit breaker for wiring, a stopper is provided at the opening end position facing the movable contact, and the movable contact that rotates from the closed position toward the open position during the breaking operation is provided as described above. The stopper is abutted against and stopped at this position, and as a stopper means, a cylindrical stopper pin is installed between the left and right side walls (insulating frame) of the arc extinguishing chamber, and a movable contact is attached to the stopper pin. The thing of the structure which made it abut and stop was known (for example, refer patent document 1).
JP 2002-208339 A

  Incidentally, as disclosed in Patent Document 1, the structure in which the stopper is a cylindrical pin has the following problems in terms of strength and function. In other words, the movable contact of the circuit breaker is made of a flat rectangular copper conductor. A movable contact is attached to the lower surface of the front end, and it can be rotated in the open / close direction around the support shaft provided at the rear end. It is supported by.

  Therefore, the movable contact that rotates from the closed position to the open end position during the breaking operation is such that the flat surface of the flat conductor (the back of the movable contact) is the peripheral surface (arc surface) of the cylindrical stopper pin described above. Will collide at high speed. For this reason, the collision load applied to the stopper pin from the movable contact is concentrated on the ridge line portion in contact with the movable contact, and the stopper pin receiving the excessive concentrated load may be broken. In addition, the installation of additional stopper pins in the arc extinguishing chamber of limited outer dimensions limits the installation space and the number of arrays of grid plates, which may affect the circuit breaker breaking performance.

  The present invention has been made in view of the above points, and its object is to solve the above-mentioned problems, avoid the concentration of collision load applied from the movable contactor to the arc extinguishing chamber, and improve the strength and reliability of the parts. Another object of the present invention is to provide a circuit breaker having an improved stopper mechanism for a movable contact provided in the arc extinguishing chamber so as to maintain a high arc extinguishing function and performance in the arc extinguishing chamber.

In order to achieve the above object, according to the present invention, a stationary contact, a rotary movable contact connected to an opening / closing mechanism, an arc extinguishing chamber, and a movable contact are provided inside a case and a cover. A circuit breaker equipped with a stopper means for regulating the opening end position, wherein the arc extinguishing chamber is a box-shaped insulating frame and a plurality of upper and lower parts arranged and held in the insulating frame along the opening / closing movement path of the movable contact It consists of stepped grid plates, and the top of the insulating frame is placed in close proximity to the inner wall surface of the cover of the housing,
At the top of the arc-extinguishing chamber, a grid ceiling plate is formed in which an abutting portion functioning as the stopper means is projected from the rear end of the grid plate, and the grid ceiling plate is movably moved vertically on the top of the insulating frame. Hold the back of the movable contact that has been held open and moved during the breaking operation against the plate surface of the abutting part, and apply the grid ceiling plate that repels and displaces under the impact load to the cover of the housing. The movable contact is restrained (Claim 1), and preferably the arc extinguishing chamber is configured in a specific manner as described below.
(1) The plate surface angle of the abutting portion formed at the rear end of the grid ceiling plate is set in accordance with the back surface angle of the movable contact, and the movable contact and the abutting portion of the grid ceiling plate face each other at the time of collision. To avoid the concentration of the impact load (claim 2).
(2) A horizontal beam straddling the left and right side walls and engaging projections are formed on the top of the insulating frame, and the tip of the grid ceiling plate is inserted into the inner side of the horizontal beam and formed on the side edge of the intermediate portion. A concave portion is fitted to the engaging protrusion and latched and held vertically.
(3) The ceiling grid plate is formed with support shafts protruding left and right from the front end portion thereof, and engaging ears protruding from the middle portion to the left and right sides, and the support shafts are formed on the left and right side walls of the insulating frame. It is inserted into the drilled bearing hole, and the engagement ears are carried on the shoulders of the left and right side walls, and are latched and held in a vertically movable manner (claim 4).

  According to said structure, the movable contactor which has moved to the separation end position by the shut-off operation has the back surface (plane) on the plate surface (plane) of the abutting portion formed at the rear end of the grid ceiling plate. A grid ceiling plate that hits the surface and simultaneously receives the collision load and repels and displaces is applied to the cover of the housing to stop the movable contact. This increases the abutting area at the time of collision compared to the conventional structure where the stopper is a cylindrical pin, and the degree of concentration of impact load applied to the stopper is relaxed by that much, improving the safety of the strength surface, and finally Specifically, the arc-extinguishing chamber can be safely protected from the collision load by receiving the collision load of the movable contact by the casing cover of the circuit breaker.

  In addition, the grid ceiling plate also serving as a stopper has a function as an arc extinguishing grid plate, thereby ensuring the required number of grid plates in the arc extinguishing chamber and exhibiting the required arc extinguishing performance.

  Furthermore, with respect to this grid ceiling plate, by setting the plate surface angle of the abutting portion protruding from the rear end toward the opening / closing movement path of the movable contact in accordance with the back surface angle of the movable contact, The impact load can be received over a wide area.

  Embodiments of the present invention will be described below based on a first example shown in FIGS. 1 to 4 and a second example shown in FIG. 1 is a side sectional view showing the overall structure of the circuit breaker for wiring (opening operation state), and FIG. 2 is a movable contactor colliding with the grid ceiling plate arranged at the top of the arc extinguishing chamber of FIG. 3 (a) to (f) are detailed structures of the arc extinguishing chamber, FIG. 4 is an enlarged view of the arc extinguishing chamber in FIG. 1, and FIGS. 5 (a) and 5 (b) are first views. It is a structure figure of the arc-extinguishing chamber by the Example of 2. FIG.

  1 to 4, reference numeral 1 denotes an insulating housing (resin molded case) of a circuit breaker having a two-part structure of a case 1a and a cover 1b, and 2 denotes a fixed contact that also serves as a main circuit terminal on the power source side. Is a fixed contact, 3 is a movable movable contact, 3a is a movable contact, 3b is a pivot of the movable contact 3, 4 is a contact holder for holding the movable contact 3, and 5 is a contact holder. 4 is a toggle link type opening / closing mechanism connected to 4, 6 is an opening / closing operation handle, 7 is a thermal overcurrent tripping device, and 8 is an arc extinguishing chamber disposed in front of the movable contact 3 along the opening / closing movement path. The movable contact 3 is opened and moved in the direction of the arrow P during the current interruption operation with the support shaft 3b as a fulcrum.

  The arc extinguishing chamber 8 includes a box-shaped insulating frame 9 made of a heat-resistant resin material, a plurality of grid plates (magnetic metal plates) 10 and a grid ceiling plate (magnetic metal plate) 11 arranged in the uppermost stage. As shown in the figure, the arcuate chamber 8 is arranged and held along the opening movement path of the movable contact 3 and the arc extinguishing chamber 8 is mounted on the casing 1 of the circuit breaker (see FIG. 1). It arrange | positions so that the top part of the flame | frame 9 may adjoin in close proximity to the inner wall face of the housing | casing cover 1b.

  Here, the grid plate 10 is a U-shaped metal plate formed by notching a slit in the center of the plate surface. On the other hand, the grid ceiling plate 11 arranged at the uppermost stage of the arc extinguishing chamber 8 forms an abutting portion 11a where the movable contact 3 collides with the rear end portion of the flat metal plate as shown in FIG. The side edge is formed with a recess 11b that fits with an engaging projection (described later) of the insulating frame 9, and the abutting portion 11a is further bent obliquely downward. The back surface of the movable contact 3 that has been moved to the separation end position and the plate surface of the abutting portion 11a come into contact with each other in the state of being mounted in the arc extinguishing chamber 8 and incorporated in the casing 1 of the circuit breaker. It is set to an angle.

  On the other hand, the insulating frame 9 of the arc extinguishing chamber 8 has a divided structure in which the rear wall portion 9b is combined with the U-shaped front wall portion 9a as shown in FIGS. In the inner surfaces of the left and right side walls, grid insertion grooves 9a-1 whose rear ends are opened in accordance with the arrangement of the grid plates 10 are formed, and after the grid plates 10 are inserted one by one here, the rear wall is formed on the front wall portion 9a. The grid plates 10 are held in place by overlapping the portions 9b.

  Further, for the grid ceiling plate 11, a cross beam 9a-2, a support step 9a-3, and an engaging projection 9a-4 are formed inside the top of the left and right side walls at the top of the front wall 9a, and the rear wall Engagement protrusions 9b-1 are formed behind the engagement protrusions 9a-4 on the inner side of the top of the left and right side walls of 9b, and the grid ceiling plate 11 is connected to the insulating frame 9 from the rear side of the horizontal beams 9a-. 2 and 9a-3 and the engaging projections 9a-4, and the recesses 11b formed on the left and right side edges of the ceiling plate are fitted into the engaging projections 9a-4 and 9b-1 of the insulating frame 9. And hold it in place.

  In this latching holding state, the engaging protrusions 9a-4 and 9b-1 latch and hold the grid ceiling plate 11 so as not to move in the front-rear direction, and the movable contact moved to the open position When the child 3 collides with the abutting portion 11a at the rear end, the grid ceiling plate 11 uses the front end portion inserted into the lower surface of the horizontal beam 9a-2 as a swing fulcrum, and the abutting portion 11a at the rear end moves upward. Supported to jump up.

  With the above configuration, an overcurrent such as a short-circuit current flows through the main circuit, and as a result, an electromagnetic repulsive force acting between the fixed contact / movable contact is received and the open position (II) from the closed position (I) in FIG. When the movable contact 3 that rotates in the direction of arrow P moves toward the separation end position, the rear surface of the movable contact 3 abuts against the grid ceiling plate 11 disposed on the top of the arc extinguishing chamber 8. Collide with the portion 11a (X portion in FIG. 2). At the same time, the grid ceiling plate 11 that has received this collision load has the abutting portion 11a at the rear end jumping upward (arrow Q) with the front end portion inserted into the insulating frame 9 of the arc extinguishing chamber 8 as a fulcrum, and confronts the upper part thereof. The movable contact 3 is stopped at this position by hitting the inclined inner wall surface 1b-1 (see FIG. 4) of the housing cover 1b. In this case, the grid ceiling plate 11 is a flat metal plate as described above, and the abutting portion 11a is a plate surface angle so as to come into contact with the back surface of the movable contact 3 which has moved to the open position. Is set. Thus, the collision load applied to the grid ceiling plate 11 is distributed and received on the plate surface of the abutting portion 11a and the housing cover 1b, and the impact load applied to the insulating frame 9 of the arc extinguishing chamber 8 is received. It is reduced.

  Thereby, the concentrated load which is a problem with the stopper pin disclosed in Patent Document 1 is eliminated, and the collision load is received by the housing cover 1b due to the jumping displacement of the grid ceiling plate 11, so that the arc-extinguishing chamber 8 is insulated. The impact load applied to the frame 9 is also light and the reliability in terms of strength is improved.

  Next, an embodiment corresponding to claim 4 of the present invention will be described with reference to FIGS. In this embodiment, the grid ceiling plate 11 held at the top of the insulating frame of the arc extinguishing chamber 8 is formed with a support shaft 11c protruding leftward and rightward at the front end, and on the rear side from the side edge to the left and right sides. Engagement ears 11d projecting in the direction are formed. On the other hand, on the insulating frame side of the arc extinguishing chamber 8, a bearing hole 9c-1 into which the support shaft 11c is fitted is drilled at the top of the left and right side walls 9c, and the upper end surface on the rear side of the side wall 9c is inclined above this. The rear end abutting portion 11a is disposed so as to protrude behind the arc extinguishing chamber 8 at this position. The other grid plates 10 arranged along the movement path of the movable contact 3 except for the uppermost grid ceiling plate 11 are formed with engaging protrusions 10a on the left and right side edges, and the engaging protrusions 10a. Is fitted into a fitting hole opened in the left and right side walls of the arc extinguishing chamber 8 so as to be latched and held at a predetermined position. Although not particularly illustrated, the top of the arc extinguishing chamber 8 is disposed so as to face the inner wall surface of the housing cover 1b (see FIG. 1) in the position where the arc breaker 8 is installed in the circuit breaker, as in the first embodiment. Has been.

  With the above configuration, the grid ceiling plate 11 is held at the illustrated position with respect to the arc extinguishing chamber 8 in a steady state. From this state, when the movable contact 3 (see FIG. 1) moves from the closed position toward the open position during the opening operation of the circuit breaker, the movable contact 3 is the same as in the first embodiment. At the same time, the rear surface of the grid collides with the abutting portion 11a formed at the rear end of the grid ceiling plate 11, and at the same time, the grid ceiling plate 11 receiving the collision load jumps upward (arrow Q) with the support shaft 11c at the front end as a pivotal support point. After that, it hits the inner wall surface of the housing cover 1b and is stopped at this position. Thereby, there exists an effect similar to Example 1, and the intensity | strength and reliability of components improve.

Side view sectional drawing of the whole structure in the state at the time of opening operation of the circuit breaker by Example 1 of this invention The perspective view showing the movable contact which collided with the grid board and grid ceiling board of the arc-extinguishing chamber corresponding to the operation state of FIG. FIG. 2 is a detailed structural view of the arc extinguishing chamber in FIG. 1, (a) is a plan view, (b) is a side view, (c) is a cross-sectional view taken along line AA in (a), and (d) is a diagram (c). Fig. 4E is an enlarged view of the latching portion of the grid ceiling plate as viewed from the direction B of Fig. 8E, (e) is a state in which the rear wall portion of the insulating frame is removed, and (c) the grid ceiling plate is viewed from the direction C of the arrow. Fig. 4F is an enlarged view of the locking portion. Fig. 5F is an enlarged view of the hanging portion of the grid ceiling plate as viewed from the direction C of the arrow in Fig. 5C with the rear wall portion of the insulating frame assembled. Enlarged view around the arc extinguishing chamber in FIG. FIG. 4 is an assembly structure diagram of an arc extinguishing chamber corresponding to Example 2 of the present invention, where (a) is a side view and (b) is a rear view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insulation housing | casing of a circuit breaker 1a Case 1b Cover 2 Fixed contact 3 Movable contact 5 Opening / closing mechanism 8 Arc-extinguishing chamber 9 Insulating frame 9a Front wall part 9a-2 Horizontal beam 9a-4 Engagement protrusion 9b Rear wall part 9b- DESCRIPTION OF SYMBOLS 1 Engagement protrusion 10 Grid board 11 Grid ceiling board 11a Butting | jumping part 11b Recessed part 11c left-hand side edge 11d Spindle 11d Engagement ear | edge part

Claims (4)

Circuit breaker equipped with a fixed contact, a movable movable contact linked to the opening and closing mechanism, an arc extinguishing chamber, and a stopper means for regulating the opening end position of the movable contact inside the case and cover housing The arc extinguishing chamber is composed of a box-shaped insulating frame and a plurality of upper and lower grid plates arranged and held in the insulating frame along the opening / closing movement path of the movable contact, and the top of the insulating frame is In what is placed in close proximity to the inner wall surface of the cover of the housing,
At the top of the arc-extinguishing chamber, a grid ceiling plate is formed in which an abutting portion functioning as the stopper means is projected from the rear end of the grid plate, and the grid ceiling plate is movably moved vertically on the top of the insulating frame. Hold the back of the movable contact that has been held open and moved during the breaking operation against the plate surface of the abutting part, and apply the grid ceiling plate that repels and displaces under the impact load to the cover of the housing. The circuit breaker is characterized in that the movable contact is stopped. 2. The circuit breaker according to claim 1, wherein a plate surface angle of an abutting portion formed at a rear end of the grid ceiling plate is set in accordance with a back surface angle of the movable contact. 2. The circuit breaker according to claim 1, wherein a transverse beam extending over the left and right side walls and an engaging projection are formed on the top of the insulating frame, and a leading end portion of the grid ceiling plate is fitted inside the transverse beam, and an intermediate portion. A circuit breaker characterized in that a recess formed in a side edge of the circuit breaker is fitted to the engagement protrusion and is latched and held vertically. 2. The circuit breaker according to claim 1, wherein the ceiling grid plate is formed with a support shaft protruding laterally from the front end portion thereof and an engaging ear projecting laterally laterally from the intermediate portion to insulate the support shaft. A circuit breaker, wherein the circuit breaker is fitted into bearing holes drilled in the left and right side walls of the frame, and the engagement ears are supported on the shoulders of the left and right side walls so as to be hooked and held vertically.

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