JP4760898B2 - Circuit breaker - Google Patents

Description

  The present invention relates to a multipolar circuit breaker for wiring breakers, earth leakage breakers, and the like, and more particularly to the structure of a main body case incorporating functional parts of a circuit breaker.

The above-mentioned circuit breaker for wiring is a current breaker consisting of a fixed contact, movable contact, and arc-extinguishing chamber in a molded resin case made up of a base and a cover. And an opening / closing mechanism, a rocker type operation handle, and an overcurrent trip device (see, for example, Patent Document 1).
Next, FIG. 7 shows a structure of a three-pole circuit breaker applied to a three-phase circuit disclosed in Patent Document 1 as a conventional example. In the figure, 1 is a main body case made of mold resin having a split structure of a box-shaped base 2 and a cover 3, 4 is a power supply side terminal, 5 is a load side terminal, 6 is a stationary contact, 7 is a movable contact, 7a is a support shaft of the movable contact 7, 8 is a contact holder for supporting the movable contact 7 of each pole, 9 is a grid type arc extinguishing chamber, and 10 is the contact holder 8 described above. An opening / closing mechanism provided with a toggle link mechanism and a latch connected to the opening / closing mechanism, 11 is a rocker type operation handle connected to the opening / closing mechanism 10, 11a is a knob of the operation handle, and 12 is a heat combining bimetal and an electromagnet. A dynamic-electromagnetic overcurrent tripping device 13 is a trip cross bar that trips the switching mechanism 10 in response to a mechanical operation signal from the overcurrent tripping device 12.

Here, in the main body case 1, three polar chambers corresponding to the R, S, and T phases of the three-phase main circuit are defined on the left and right sides with a phase interval wall between them. A fixed contact 6, a movable contact 7, and an overcurrent trip device 12 are connected between the side terminal 4 and the load side terminal 5, and further along the opening movement path of the movable contact 7 on the power source side An arc extinguishing chamber 9 is disposed in the area.
In addition, the opening / closing mechanism 10 and the operation handle 11 common to each pole are housed and arranged on the upper side (cover side) of the central pole chamber corresponding to the S phase among the pole chambers defined in the body case 1. The knob 11a of the operation handle 11 protrudes outward through the handle hole 3a opened at the center of the upper surface of the cover 3 at this storage position.

  The current interrupting operation of the circuit breaker configured as described above is described in detail in Patent Document 1. When a relatively small overcurrent continuously flows like an overload current, the bimetal of the overcurrent tripping device 12 is curved. Then, the operation end presses the lever of the trip cross bar 13 and follows it to release the latch of the opening / closing mechanism 10. As a result, the opening / closing mechanism 10 is tripped, and the opening / closing spring rotates the contact holder 8 in the clockwise direction, and the movable contact 7 held by the contact holder 8 is moved to the open position to cut off the current. .

  In addition, when an excessive current such as a short circuit current flows, it does not wait for the tripping operation of the switching mechanism 10 by the electromagnet of the overcurrent tripping device 12 and works between the fixed contact 6 and the movable contact 7. Due to the electromagnetic repulsive force, the movable contact 7 starts the opening operation first, and with a slight delay, the opening / closing mechanism 10 trips to drive the contact holder 8 in the clockwise direction and hold it in the contact holder 8. The movable contact 7 is moved to the opening position to interrupt the current. Note that the arc generated between the contact points of the stationary contact 6 and the movable contact 7 when the current is interrupted receives the electromagnetic driving force and the pressure of the arc gas generated around the arc. As is well known, it is driven by the arc extinguishing chamber 9 and is extinguished by being pushed between the grid plates (current limiting interruption).

  On the other hand, in the circuit breaker of FIG. 7, in order to stop the movable contact 7 driven at a rapid speed from the closing position toward the opening position during the current breaking operation, the main body case 1 is stopped. A metal stopper pin 14 is fitted in a concave groove formed on the overlapping surface of the base 2 and the cover 3 and sandwiched between the movable contact 7 and moved to the opening end position. Is abutted against the stopper pin 14 and stopped at this position.

Further, for the central pole chamber of the main body case 1 containing the opening / closing mechanism 10 and the operation handle 11, arc gas generated in the space in the arc extinguishing chamber by the heat of the arc generated between the fixed / movable contacts (in the arc gas, (Including metal particles that evaporate from the surface of the mold resin case and fixed, movable contact surface) and diffused to adhere to the switching mechanism 10 and the operation handle 11. In order to prevent the insulation deterioration of the operation handle and the movement of the opening / closing mechanism from being lowered, the arc extinguishing chamber is constructed by laying a shielding plate (bending fiber) 15 on the upper surface side of the arc extinguishing chamber 9 in the structure of FIG. 9 space is isolated from the opening / closing mechanism and the operation handle.
JP 2000-67730 A (FIG. 1)

Incidentally, the conventional circuit breaker shown in FIG. 7 has the following problems.
First, the current interrupting operation, means for stopping the movable contact separated from the fixed contact by the operation handle OFF operation, and the opening / closing mechanism and operation of the arc gas generated by the current interruption from the arc extinguishing chamber As a means for preventing diffusion toward the handle, the parts of the stopper pin 14 and the shielding plate 15 are assembled to the main body case 1 in the conventional structure, which increases the number of parts and the number of assembly steps of the circuit breaker. cost) high.

Further, in the structure in which the stopper pin 14 is inserted into a concave groove formed on the mating surface of the base 2 and the cover 3 of the main body case 1, the circuit breaker is installed in the panel with the operation handle 11 facing the front. If the cover 3 is removed during maintenance, the stopper pin 14 may fall off. In addition, when the movable contact 7 (copper material) comes into contact with the metal stopper pin 14 that has been heated to a high temperature due to arc heat, the two are welded together, and after the current is interrupted, the movable contact 7 returns to the closed position. There is also the possibility of causing trouble that disappears.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a stopper function for stopping the movable contact at the opening end position, and a shielding function for preventing arc gas diffusion to the opening / closing mechanism and the operation handle. An object of the present invention is to provide an improved circuit breaker that is provided on the cover itself so that the number of parts can be reduced and the cost can be reduced.

In order to achieve the above object, according to the present invention, a molded resin main body case composed of a base and a cover is provided with a stationary contact, a movable contact, a current interrupting section composed of an arc extinguishing chamber, an opening / closing mechanism, a rocker type In a multi-pole circuit breaker which is equipped with an operation handle and each functional component of an overcurrent trip device, and the opening / closing mechanism and the operation handle are accommodated in a polar chamber partitioned at the left and right center of the main body case,
A barrier partition that partitions between the arc extinguishing chamber and the opening / closing mechanism is integrally formed on the inner side of the cover, and a movable contact that is separated from the fixed contact is formed at the end of the barrier partition. The stopper part which consists of a 2 step | paragraph collision end surface from which the angle to which it stops is different is formed.

  In the above configuration, the central pole chamber of the main body case that houses the operation handle and the opening / closing mechanism has a barrier partition formed in the polar chamber, and a space opened in the cover of the main body case in accordance with the molding process of the stopper portion. The cover is covered and a shielding cover is attached to the upper surface of the cover (Claim 2). Further, the shielding cover is fitted to the knob portion of the operation handle, and the end portion of the shielding sheet extending in the handle operation direction is positioned upward. As a member that also serves as a holding guide that is pushed in and guided to the gap between the cover and the shielding cover is superimposed on the upper surface of the cover of the main body case, it is fastened to the base together with a fastening screw and fixed. Item 3).

  According to the above configuration, the stopper pin provided in the circuit breaker having the conventional structure, the barrier plate of the arc extinguishing chamber (see FIG. 7) are omitted, the barrier partition wall integrally formed on the cover of the main body case, and With the stopper portion formed on the partition wall, a stopper function for stopping the movable contact at the opening end position and a shielding function for preventing arc gas diffusion to the opening / closing mechanism and the operation handle can be secured. As a result, the cost of the product can be reduced together with the reduction in the number of parts and the number of assembly steps as compared with the circuit breaker having the conventional structure.

  Hereinafter, embodiments of the present invention will be described based on the examples shown in FIGS. 1 is a side sectional view showing the internal structure of a circuit breaker (wiring breaker), FIG. 2 is a sectional view of the cover of the main body case in FIG. 1, and FIGS. 3 and 4 are the covers shown in FIG. FIG. 5 is an exploded perspective view of the circuit breaker shown in FIG. 1, and FIG. 6 is a structural view of a shielding lid attached to the cover, corresponding to FIG. Are denoted by the same reference numerals, and description thereof is omitted.

The circuit breaker of the illustrated embodiment has basically the same configuration as that of the conventional example shown in FIG. 7, but is combined with the base 2 with respect to the main body case 1 made of molded resin that accommodates each functional part of the circuit breaker. The cover 3 is configured as follows.
That is, as shown in FIGS. 2 and 3, on the inner side of the cover 3, a barrier partition wall that extends downwardly so as to partition the top accommodating space of the arc extinguishing chamber 9 (see FIG. 1) provided in each pole chamber in the main body case. 3b is integrally formed, and a stopper 3c is formed at the lower end of the barrier partition wall 3b so as to abut against the movable contact 7 that is separated from the fixed contact 6 and stop it at the opening end position. In addition, the cover 3 is formed with a bearing frame 3d of the contact holder 8 and a phase interval wall 3e that partitions the left and right pole chambers corresponding to the R, S, and T phases of the main circuit, as in the conventional example. The opening / closing mechanism 10 and the operation handle 11 shown in FIG. 1 are accommodated in the central polar chamber (S phase).

Further, as shown in FIG. 4, a pocket-like recess 3 f is formed on the upper surface side of the cover 3 to insert and set auxiliary devices such as an auxiliary switch and an alarm switch on both the left and right sides of the accommodating portion of the operation handle 11. The cover 3 is provided with a top cover 16 that can be opened and closed so as to cover the recess 3f.
In the circuit breaker of FIG. 1 in which the functional parts are mounted on the main body case 1 in which the cover 3 is combined with the base 2, the movable contact 7 is separated from the fixed contact 6 by tripping and turning off the handle to open the contact. Then, the movable contact 7 comes into contact with the end face of the stopper portion 3c formed on the cover 3 at the opening end position and stops at this position. Further, the arc gas generated in the space of the arc extinguishing chamber 9 due to the overcurrent interruption operation is blocked by the barrier partition wall 3b and is not directly blown out into the space containing the opening / closing mechanism 10 and the operation handle 11, and the arc extinguishing chamber 9 It flows between the grid plates and is discharged outward from the end (power supply side) of the main body case 1.

  Thereby, like the circuit breaker of the conventional example shown in FIG. 7, there is no need to additionally deploy components such as the stopper pin 14 and the shielding plate 15 covering the arc extinguishing chamber 9 inside the main body case 1. A barrier function that stops the movable contact 7 at the opening end position by a barrier partition wall 3b and a stopper portion 3c that are integrally formed with the cover 3 made of mold resin, and shielding that prevents diffusion of arc gas to the opening / closing mechanism 10 and the operation handle 11. Function can be secured. Therefore, compared with the conventional circuit breaker, the number of parts and the number of assembling steps can be reduced and the cost can be reduced.

  Depending on the type of circuit breaker, there are a structure in which the support shaft center of the movable contact 7 and the rotation shaft center of the contact holder 8 for supporting the movable contact 7 are concentric and an eccentric structure. is there. Further, in the latter structure, the contact holder 8 is rotated by the movement trajectory of the movable contact 7 that is opened by receiving an electromagnetic repulsion force and the trip operation of the opening / closing mechanism 10 so that the movable contact 7 is brought into the open position. It is different from the driving trajectory to drive. For this reason, a slight deviation occurs in the collision position and angle of the movable contact 7 that abuts against the stopper portion 3c at the opening end position. Therefore, in the stopper portion 3c formed on the cover 3 of the illustrated embodiment, the two-stage collision end surface is changed in angle to the stopper portion 3c so as to correspond to the collision position and angle deviation of the movable contact 7 as shown in FIG. In any case, the movable contactor 7 that has moved to the opening position is applied to the surface and stopped. The stopper 3c may be formed only in the S phase.

  By the way, in the cover 3 of the illustrated embodiment, the shape of the stopper portion 3c formed on the barrier partition wall 3b of the polar chamber (S phase) arranged in the center is formed from the tip of the barrier partition wall 3b so as to avoid interference with the operation handle 11. It cuts so that it may protrude toward the opening-and-closing mechanism 10, and the space 3g is formed in the upper direction (refer FIG. 2). Therefore, since the mold for molding the cover 3 requires a slide core for the undercut process of the stopper portion 3c, the upper surface of the molded cover 3 has a hole leading to the space 3g. (Hole for setting the slide core) will open.

However, if the opening hole is left unblocked, the driver can be used when the top cover 16 (see FIG. 1) is opened and the attached device such as the auxiliary switch is attached to or detached from the recess 3f of the cover 3. There is a risk that the tip of the (tool) enters the space 3g from the opening hole and touches the charged part.
Therefore, in the illustrated embodiment, a separate cover 17 (molded resin molded product) is attached to the upper surface of the cover 3 so as to close the hole in the space 3g (see FIGS. 1 and 5). In the illustrated embodiment, as a means for closing a gap remaining between the operation handle 11 and the peripheral edge of the handle hole 3a opened on the upper surface of the cover 3 to prevent dust and the like from entering the case from the outside. In addition to the shielding lid 17, a flexible shielding sheet 18 that extends in the front-rear direction by being fitted to the knob 11 a of the operation handle 11 is laid. And after extending the edge part of this sheet | seat so that the opening hole of the said space 3g may be covered with this shielding sheet 18, this extended edge part is guided and hold | maintained with the said shielding cover 17, and the detail The structure will be described with reference to FIGS.

That is, as shown in FIGS. 6A and 6B, the shielding lid 17 has a screw seat 17a that projects to both the left and right sides, and U that projects to the lower surface side of the lid plate to guide and hold the end of the shielding sheet 18. A guide 17b having a shape and an extended piece 17c projecting forward are formed. On the other hand, a recess 3 i corresponding to the extension piece 17 c of the shielding lid 17 is formed on the upper surface of the cover 3.
Then, in the final assembly process of the circuit breaker in which various functional components are mounted on the base 2 of the main body case 1, the base 3 is covered with the cover 3, and the hole of the space 3g opened on the upper surface of the cover is closed. Then, the shielding lid 17 is overlapped at a predetermined position, and the end portion of the shielding sheet 18 previously fitted and laid on the knob 11 a of the operation handle 11 is inserted into the U-shaped guide 17 b of the shielding lid 17 at this position. In this state, a bolt 19 (see FIG. 5) passed through the screw seat 17a of the shielding lid 17 and the mounting screw hole 3h formed in the cover 3 is screwed to the base 2 to fasten the cover 3 and the shielding lid 17 together. Fix it.

  In this assembled state, as shown in FIG. 1, the hole in the space 3 g opened on the upper surface of the cover 3 for the undercut process at the time of molding is closed by the shielding lid 17 and the shielding sheet 18. The end portion of the shielding sheet 18 is inserted between a recess 3 i formed on the upper surface of the case 3 and an extension piece portion 17 c of the shielding lid 17 so as to be slidably guided and held.

Side view sectional drawing which shows the assembly structure of the circuit breaker by the Example of this invention Sectional view of the cover of the main body case in FIG. 2 is an external perspective view of the cover of FIG. 2 viewed from the back side. FIG. 2 is an external perspective view of the cover of FIG. 2 viewed from the upper surface side. The disassembled perspective view of the main body case of the circuit breaker shown in FIG. FIG. 6 is a structural diagram of the shielding lid in FIG. 5, (a) is an external view seen from the back side, (b) is a front view. Side view sectional view showing assembly structure of circuit breaker of conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main body case 2 Base 3 Cover 3a Handle hole 3b Barrier partition 3c Stopper part 6 Fixed contact 7 Moveable contact 8 Contact holder 9 Arc extinguishing chamber 10 Opening / closing mechanism 11 Operation handle 12 Overcurrent tripping device 17 Shielding lid 17a Screw seat 18 Shielding sheet

Claims (3)

The main parts made of molded resin consisting of a base and a cover are equipped with functional parts such as a stationary contact, a movable contact, a current interrupting part consisting of an arc extinguishing chamber, an open / close mechanism, a rocker-type operating handle, and an overcurrent trip device. A multi-pole circuit breaker mounted, wherein the opening and closing mechanism and the operation handle are housed and arranged in a polar chamber partitioned at the left and right center of the main body case,
A barrier partition that partitions the arc extinguishing chamber and the opening / closing mechanism is integrally formed inside the cover, and a movable contact that is separated from the fixed contact is stopped at the opening end position at the tip of the barrier partition. A circuit breaker characterized in that a stopper portion composed of two stages of collision end faces with different angles is formed.   The circuit breaker according to claim 1, wherein the central pole chamber of the main body case accommodating the operation handle and the opening / closing mechanism is attached to the cover of the main body case in accordance with the molding process of the barrier partition wall formed in the polar chamber and the stopper portion. A circuit breaker which covers an open space and has a shielding lid attached to the upper surface of the cover.   3. The circuit breaker according to claim 2, wherein the shielding lid is fitted into the knob portion of the operation handle and pushes the end portion of the shielding sheet extending in the handle operation direction from above to form a gap between the cover and the cover. A circuit breaker characterized by also serving as a holding guide for guiding, wherein the shielding lid is superposed on the upper surface of the cover of the main body case, and then fastened to the base together with a fastening screw.