JPH08227648A - Circuit breaker - Google Patents

Abstract

PURPOSE: To simplify a structure surrounding an arc-extinguishing chamber in a circuit breaker equipped with a deion type arc-extinguishing device. CONSTITUTION: An insulator 14 striding over a grid 2 as well as a magnetically impelled iron-core 13 is integrally formed out of molded resin and a grid 2 is inserted in a groove formed on the side wall 14a of the insulator 14. In addition, the insulator 14 is coupled to the leg of the core 13 via a recess formed on the side wall 14a. According to this construction, the support plate of the grid 2 and the insulation member of the core 13 are integrated with the insulator 14 and a structure is simplified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker such as a wiring breaker or an earth leakage breaker, and more particularly to an arc-extinguishing means for an electromagnetic repulsion type circuit breaker.

[0002]

2. Description of the Related Art FIG. 1 shows an arc extinguishing device for the above circuit breaker.
A so-called deionized type shown in FIG. 9 is known.
This arc-extinguishing device is one in which grids 2 each having a V-shaped notch through which a movable contact 1 passes are stacked at appropriate intervals, and these are supported by a support plate 3 of an insulating material (fiber, polyester glass mat laminated plate, etc.), The grid 2 is fixed to the support plate 3 by adhesion or caulking.

FIG. 20 is a vertical sectional view showing a power source side portion of a circuit breaker equipped with the above-mentioned deionization type arc extinguishing device. An end 5a of a fixed contactor 5 integrally formed with a power source side terminal 4 is a movable contactor. 1 is provided with a fixed contact 7 which is folded back in a U-shape along 1 and which is in contact with the movable contact 6 of the movable contactor 1 at the tip of the folded back end 5a. Further, an arc horn 9 for guiding the arc 8 generated between the movable and fixed contacts 6 and 7 toward the arc extinguishing device is attached to the fixed contact 5.

Here, the folded-back end portion 5a of the fixed contact 5
Since the directions of the currents respectively flowing in and the movable contactor 1 parallel thereto are opposite to each other as shown by an arrow A, an electromagnetic repulsive force acts between these currents and a large current such as a short circuit current is generated. When flowing, the movable contact 1 is repelled by this electromagnetic repulsive force. As a result, although the operating principle is omitted, the movable contactor 1 is driven by the current limiting mechanism 10 and is rapidly driven to the open position indicated by the chain line without waiting for the operation of the opening / closing mechanism 11. At that time, the arc 8 receives a force in the direction of the arrow B by the magnetic field of the current flowing through the folding end portion 5a, and is driven toward the back of the arc extinguishing device. This arc 8 is drawn further into the interior due to the deviation of its own magnetic flux generated by the existence of the grid 2, and is divided by the grid 2 to increase the arc voltage. At the same time, the arc 8 is cooled by the arc-extinguishing gas generated from the insulator forming the support plate 3, and is rapidly extinguished together with the constricting action due to the increase in the pressure inside the case 12.

On the other hand, in the electromagnetic repulsion type circuit breaker as shown in FIG. 20, the folded end 5a of the fixed contact 5 is
A U-shaped magnetically driven iron core is attached to the circuit breaker, and the magnetic flux of the above-mentioned current flowing through the folded-back end portion 5a is converged on the magnetically driven iron core to enhance the action of the magnetic field on the arc. Are known.

[0006]

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention A deer ion type arc extinguishing device having grids stacked in multiple stages is movable.
In the circuit breaker arranged around the fixed contact, since the grid is conventionally fixed to the support plate by caulking or bonding, a lot of man-hours are required for the grid mounting work. In addition, since there is no effective means to shield the grid from the arc, the grid contacts the arc and melts and scatters, and metal fine particles adhere to the opening / closing mechanism part and hinder the smooth operation of the grid. There was a great risk of reducing the insulation strength between them. On the other hand, in a circuit breaker in which a magnetically driven iron core is attached to a folded end portion of a fixed contact provided with a fixed contact, the conventional circuit breaker described above has been disclosed.
As can be seen in Japanese Patent Publication No. 6, the supporting plate for supporting the grid and the insulating member for covering the magnetically driven iron core are separately provided, so that the structure must be complicated. Therefore, the present invention provides a circuit breaker that simplifies the structure of the arc extinguishing device part to reduce the number of assembling steps, prevents damage to the grid due to an arc, and improves the breaking performance. It is intended.

[0007]

In order to achieve the above object, the present invention according to claim 1 provides a U-shaped end portion of a fixed contact provided with a fixed contact along a movable contact. In a circuit breaker in which an arc-extinguishing device having a grid that is folded back and stacked in multiple stages is arranged around the movable and fixed contacts, an insulator having a pair of left and right side walls connected to each other is integrated with a molding resin. It is assumed that the grid is provided by molding, and the grids are respectively inserted in the groove formed in multiple stages on the facing surface of the side wall of the insulator.

In order to achieve the above object, the present invention according to claim 2 is such that the end of the fixed contact provided with the fixed contact is folded back in a U-shape so as to be along the movable contact.
A U-shaped magnetic drive iron core was attached to the folded end portion, and arc extinguishing devices equipped with grids stacked in multiple stages were connected to each other in a circuit breaker arranged around the movable / fixed contact. An insulator having a pair of left and right side walls is provided by integral molding of a molding resin, and grids are respectively inserted into groove grooves formed in multiple steps on the facing surface of the side wall of the insulator, and the insulator is formed on the bottom surface of the side wall. The leg of the magnetically driven iron core is fitted through the formed recess.

In the above-mentioned circuit breaker, if the projecting portion which covers the grid inserted in the groove is integrally formed around the groove on the side wall of the insulator, the protection of the grid from the arc becomes more complete.

In the circuit breaker described above, if a shield wall is formed integrally at the end of the insulator on the opening / closing mechanism side to close the side walls except for the moving path of the movable contact, the arc gas enters the opening / closing mechanism side. It is effective in preventing

In the above circuit breaker, when the groove for inserting the grid is formed from the end surface on the power source side to the end surface on the load side of the side wall of the insulator, the grid inserted in this groove is formed on the insulator. It can be pressed and fixed with the protective plate attached. In that case, the protective plate may be provided with a gas vent valve for discharging the arc gas generated when the current is cut off by elastic deformation of the valve body. Further, when the groove for inserting the grid is formed from the load side end surface of the side wall of the insulator to the front side of the power source side end surface, it can be pressed and fixed by the insulating partition attached to the insulator.

In the above circuit breaker, if the width of the space between the side walls of the insulator is widened from the vicinity of the fixed contact toward the power source side in a V shape, the movement of the arc in the depth direction of the grid is promoted. Effective above. Further, inside the left and right side walls of the insulator, auxiliary side walls for adjusting the distance between these side walls can be mounted.

[0013]

In the present invention, the grid is formed by forming the groove on the side wall facing surface of the insulator integrally molded with the molding resin. As a result, the grid can be attached only by inserting it in the groove, and caulking and bonding work are unnecessary. In addition, since the insulator made of mold resin can have a sufficient thickness of the side wall, the space volume in the insulator is reduced to increase the internal pressure around the arc when the current is cut off.
In addition to enhancing the arc narrowing action, the insulator and the arc are brought close to each other to generate a large amount of arc extinguishing gas from the insulator, which facilitates enhancing the arc cooling effect. At this time, since the internal pressure is first received by the insulator, the pressure load on the case and cover of the circuit breaker body is reduced, and the pressure resistance design condition is relaxed.

On the other hand, when the magnetically driven iron core is provided at the folded end of the fixed contactor, the insulator is fitted on the leg of the magnetically driven iron core through the recess formed in the bottom surface of the side wall. As a result, the support plate of the grid and the insulating member of the magnetically driven iron core are integrated with the insulator, and the structure is simplified. Further, since the magnetically driven iron core is covered with the insulator, it is not damaged by the arc.

If the groove of the insulator is deepened so that the legs of the grid fit within it, the grid can be effectively protected from the arc by itself. By integrally forming the overhanging part that covers the outer surface,
The grid has no exposed surfaces and complete protection from arcs.

If a shield wall that blocks the side walls except for the moving path of the movable contact is integrally formed at the end of the insulator on the opening / closing mechanism side, movement of arc gas generated in the insulator to the opening / closing mechanism is suppressed. As a result, the risk of malfunction of the switching mechanism and deterioration of insulation strength due to the adhesion of contact melts in the arc gas is reduced. Further, the shielding wall enhances the closing property of the insulator, and the arc extinguishing due to the increase in the internal pressure is further promoted. In that case, if a shielding plate is attached to the end of the insulator on the power supply side, the increase in internal pressure becomes more remarkable.

The groove into which the grid is inserted is preferably formed as a groove whose one end is closed from one end surface of the side wall of the insulator to the front of the other end surface. In that case, the open end of the groove, that is, The grid insertion end may be on either the power supply side or the load side. When the grid is inserted from the power supply side of the end face of the side wall, the grid can be pressed and fixed by the protective plate that is attached to the arc gas discharge port of the insulator to prevent the intrusion of foreign matter. In order to prevent the arc gas from entering the opening / closing mechanism section, it can be fixed by being pressed by an insulating partition attached to an insulator. The protective plate is preferably provided with a gas vent valve for discharging arc gas due to elastic deformation of the valve body, which facilitates discharge of arc gas.

If the width of the space between the side walls of the insulator is widened in a V shape from the vicinity of the fixed contact toward the power supply side, the arc generated on the fixed contact is moved to the power supply side by the pressure of the arc gas. It is promoted and wear of fixed contacts is reduced.

In order to improve the arc extinguishing performance, it is necessary to cool the arc to increase the arc voltage and reduce the so-called I ² t (I: passing current, t: arc time). When the power rises, the arc power A _P (the product of the passing current and the arc voltage) increases and the inner pressure rises. In some cases, excessive inner pressure may exceed the strength of the case or cover of the circuit breaker body. . Therefore, it is necessary to properly select the spacing between the side walls of the insulator in consideration of the balance between the allowable pressure of the case and the cover and the arc extinguishing performance. By using a common insulator for circuit breakers having different breaking capacities, it is possible to appropriately adjust the distance between the side walls of the circuit breakers according to the breaking capacities.

[0020]

Embodiments of the present invention will be described below with reference to FIGS. Note that the same reference numerals are used for the portions corresponding to the conventional example. FIG. 1 is a perspective view of a movable / fixed contact portion in a state in which an insulator, a grid, and a magnetically driven iron core are vertically broken, FIG. 2 is a perspective view of an insulator and a grid inserted therein, and FIG. It is a perspective view of the fixed contactor with which the magnetic drive iron core was attached, and the movable contactor in the state where it was separated from this.

In FIG. 3, the fixed contact 5 integrally formed with the power source side terminal 4 has its opposite end 5a folded back in a U shape, and the fixed contact 7 is joined to the upper surface of the tip of this folded back end 5a. Further, the magnetically driven iron core 13 is attached from the lower surface side. The width of the folded-back end portion 5a is smaller than that of the main body portion 5b as shown in the drawing. An arc horn 9 for guiding the leg of the arc driven by the magnetically driven iron core 13 to the grid 2 side is attached to the main body portion 5b. The base portion of the arc horn 9 is inserted into the square hole of the main body portion 5b, and the tip thereof is caulked and fixed.

The magnetically driven iron core 13 has a pair of left and right legs 13a.
And a connecting portion 13b for connecting them, which is U-shaped,
The front-rear width of the connecting portion 13b is narrower than that of the leg portion 13a. Further, the left and right width of the connecting portion 13b is wider than the folded end portion 5a of the fixed contact 5, and there is a slight gap between the side surface of the folded end portion 5a and the inner wall surface of the leg portion 13a, although not clearly shown. I am open. The magnetically driven iron core 13 is fastened to the folded-back end portion 5a by a screw (not shown) penetrating the connecting portion 13b.

On the other hand, in FIG. 2, the insulator 14 is composed of a pair of left and right side walls 14a and connecting portions 14b and 14c for connecting them to each other at an upper portion and a front portion, respectively, and is made of an arc-resistant melamine type molding resin. It is integrally molded. A groove 15 having a rectangular cross section into which the grid 2 is inserted is formed diagonally from the power supply side end surface (left side end surface of FIG. 2) of the side wall 14a to the front of the load side end surface (also right side end surface). It is formed in multiple stages (here, five stages) so as to descend.

The grid 2 has a V-shaped notch 16 through which the movable contact 1 passes, and is inserted into each groove 15 in the arrow direction of FIG. 2 so as to straddle the left and right side walls 14a. In that case,
Both legs 2a of the grid 2 are housed so as to be hidden in the groove 15, and the connecting portion 2b for connecting these is formed of an insulator 14.
Is pushed in from the front surface (the end surface on the left side in FIG. 2) until it is sunk, and the tips of the two leg portions 2a abut on the inner wall of the groove 15. Further, the lateral width of the grid 2 is slightly larger than the distance between the opposed bottom surfaces of the groove 15, and the grid 2 is press-fitted and fixed between the bottom surfaces.

Further, the left and right side walls 14a of the insulator 14 are formed with recesses 17 which are open from the bottom surface to the front surface, and the insulator 14 is provided with the magnetically driven iron core 13 (FIG. 3) through the recesses 17.
Is fitted to the leg portion 13a of the. In that case, the inner portion of each side wall 14a, which is divided into two parts by the recess 17 to the left and right, is
The folded end 5a of the magnetic drive iron core 13 and the leg portion 13a of the magnetic drive iron core 13 enter the above-mentioned gap and hit the connecting portion 13b of the magnetic drive iron core 13 to be positioned in the downward and left and right directions. Further, in the forward direction (leftward in FIG. 3), the back wall 17 a of the recess 17 is positioned by abutting the end face of the leg 13 a of the magnetically driven iron core 13 on the front side in FIG. 3. FIG. 1 shows a state in which the insulator 14 holding the grid 2 is fitted onto the magnetically driven iron core 13 of the fixed contact 5 in this manner, and the insulator 14 is inside a case (not shown) of the circuit breaker. In the above, the cover attached thereto presses and fixes the corner portion of the upper connecting portion 14b on the front side in FIG.

In the embodiment shown above, the support plate for supporting the grid 2 and the insulating member for covering the magnetically driven iron core 13 are integrated as an insulator 14. Therefore, the conventional two parts become one part, and the structure is simplified accordingly. In addition, in the insulator 14 integrally molded with the molding resin, the thickness of the side wall 14a for supporting the grid 2 is made larger than that of the conventional supporting plate as shown in the figure, so that both leg portions 2a of the grid 2 are set in the groove 15. It is possible to make it fit perfectly. Therefore, both legs 2a are less likely to be damaged by the arc, and thus the molten metal is less scattered. In addition, since the grid 2 is fixed only by press-fitting it into the groove 15, no labor such as bonding or caulking is required.

On the other hand, the inner space of the insulator 14 that straddles the grid 2 and the magnetically driven iron core 13 and whose left and right side walls 14a face each other at a narrow interval is closed. Therefore, the internal pressure around the arc is greatly increased due to the generation of the arc gas, and the voltage of the narrowed arc is also significantly increased. In this case, this internal pressure is first received by the insulator 14, so that the pressure load on the case and cover of the circuit breaker main body is small, despite the large increase in the internal pressure.

Further, since the thick side wall 14a easily contacts the arc, a large amount of arc-extinguishing gas is generated from the insulator 14, and the arc is deionized and cooled by the wall surface at a relatively low temperature. A rapid insulation recovery is provided. In that case, if the insulating material 14 is made of a polymethylpentene resin, a polymethylmethacrylate resin, a polyacetal resin, a polybutylene terephthalate resin, a polycarbonate resin, or the like, which is likely to generate hydrogen gas having a high arc cooling effect, the barrier performance is further improved. improves.

FIG. 4 shows the groove 15 on the side wall 14a of the insulator 14.
FIG. 14 is a perspective view of a main part of an embodiment in which an overhanging portion 14d that covers the grid 2 is integrally formed around the periphery of the. The figure shows the bulging portion 14d cut at the center and one side thereof is shown from the inside of the side wall 14a. The bulging portion 14d is formed in a U-shape straddling the left and right side walls, and the front surface (left end of the figure). It has a bag shape with only the surface open. According to such a configuration, the grid 2 is entirely covered with the insulator 14 even on the upper and lower surfaces exposed from the groove 15 and the inner peripheral surface along the U-shaped notch 16, and is completely protected from the arc.

In FIG. 5, the groove 15 is formed on the outside of the tips of both legs 2a.
Grid 2 with claws 2c that bite into the bottom of the unit
FIG. The side-to-side dimension of the claw 2c is set to be slightly larger than the bottom-side dimension of the groove 15, and when the grid 2 is press-fitted into the groove 15, the leg 2a is elastically deformed inward and the claw 2c is pushed to the back. It enters and bites into the bottom of the groove 15. According to such a configuration, the grid 2 is more securely fixed, and the grid 2 does not vibrate due to the alternating magnetic field based on the current flowing through the circuit breaker.

FIG. 6 shows an arc horn 9 on a magnetically driven iron core 13.
It shows an embodiment in which the is integrally formed. The magnetically driven iron core 13 can be manufactured, for example, by press molding from an iron plate. At this time, if the arc horn 9 is also integrally formed by cutting and bending as shown in the drawing, the number of parts is reduced and the structure is further simplified.

FIG. 7 shows an end portion of the insulator 14 on the opening / closing mechanism side.
It shows an embodiment in which a shielding wall 14e that closes between the side walls 14a is integrally formed, (A) is a front view, and (B) is a longitudinal sectional view thereof. Slits 18 are provided on the shielding wall 14e in the vertical direction along the moving path of the movable contact 1. According to such a configuration, the movement of the arc gas generated in the insulator 14 to the opening / closing mechanism portion is suppressed by the shielding plate 14e, and the operation failure of the opening / closing mechanism due to the adhesion of the contact melt in the arc gas and the insulation strength The risk of decline is reduced. Insulator 1
The inner space of 4 becomes more closed, and the arc extinguishing action due to the increase in internal pressure is further promoted.

Further, in the embodiment shown in FIG. 7, a vertical groove 19 is provided at the end portion on the front surface side (left side in the drawing) of the insulator 14 on the opposite surface of the side wall 14a so as to intersect with the groove 15. A strip-shaped shield plate 20 (shown by a chain line) made of a fiber or the like is inserted into the vertical groove 19 as shown by an arrow. With such a configuration, the increase in the internal pressure in the insulator 14 becomes more remarkable, and the breaking performance is further improved. In this case, if there is a risk that the inner pressure becomes too high and the insulator 14 is damaged, the pressure is adjusted by appropriately making a hole in the shield plate 20. This type of shield plate is usually mounted on the molded case of the circuit breaker body, but when mounted on the insulator 14, the shield plate 20 is incorporated into the arc extinguishing device, which simplifies the assembling configuration.

8 and 9 show an embodiment in which the grid inserted into the insulator from the power supply side is pressed and fixed by the protective plate. FIG. 8A is a front view of the protective plate, and FIG. A side view thereof, FIG. 9A is a front view of the insulator, and FIG. 9B is a side view thereof. Here, in this embodiment, a shield plate for increasing the internal pressure is not attached to the insulator 14, and in order to prevent the entry of foreign matter from the arc gas discharge port (the left side opening in FIG. 9B). The protective plate 21 is attached to the insulator 14.

The protection plate 21 is integrally molded from an arc-resistant resin such as nylon in the shape of FIG. 8, and is provided on the left and right along the power supply side end surface of the side wall 14a of the insulator 14 of FIG. 9 (the left end surface of FIG. 9B). A pair of pressing plates 21a, a connecting plate 21b connecting the pressing plates 21a at their upper ends, a strip-shaped closing plate 21c that closes the openings between the pressing plates 21a with a front and rear gap, and one end at the lower end of the pressing plate 21a. A pair of left and right U-shaped mounting legs 21d connected to each other, a pair of left and right connecting rods 21e connecting the other end of the mounting legs 21d and the lower end of the closing plate 21c, and a pair of left and right extending from the upper end of the pressing plate 21a. It consists of a hook 21f. Further, on the side of the pressing plate 21a facing the side wall 14a (on the right side in FIG. 8B), pressing protrusions 21g are provided in multiple stages in accordance with the groove 15, and the mounting legs 21
Angle-shaped engaging projections 21h are provided on the lower surface of d.

On the other hand, the insulator 14 is provided with a groove 15 extending from the power source side end surface of the side wall 14a to the front side of the load side end surface (the right side end surface of FIG. 9B), and the hook 21f of the protective plate 21 is provided above the side plate 14a. The engaging step portion 14f is provided in accordance with the above. After the grid 2 is inserted into the insulator 14 from the power source side, the protective plate 21 is engaged with the hook 21f by the engagement step portion 1
4f, and then the mounting leg 21d is pushed into the recess 17 of the side wall 14a and mounted as shown by the chain line in FIG. 9 (B). In this case, a wall 14g is provided in the lower part of the front surface of the recess 17, and the mounting leg 21d pushed into the recess 17 is fixed by the engagement projection 21h being locked by the wall 14g. In this state, the pressing plate 21a contacts the end surface of the side plate 14a, and the pressing protrusion 21g presses the end surface of the grid 2 to fix it. As a result, the grid 2 is securely fixed even when vibration is generated only by press fitting into the groove 15. On the other hand, the protective plate 21 closes the opening of the insulator 14 through the front and rear gaps by the closing plate 21c to prevent foreign matter such as electric wire scraps from entering and discharge arc gas from the gaps.

10 to 14 show an embodiment in which a grid inserted into the insulator from the load side is pressed and fixed by an insulating partition wall. FIG. 10 is a perspective view of the insulator and the grid inserted therein. 11 is a bottom view of the insulator, FIG. 12A is a front view of the insulating partition, FIG. 12B is a sectional view taken along the line BB, FIG. 12C is a rear view thereof, and FIG. 13A is a plan view, FIG. 13A is a front view of the protective plate, and FIG.
FIG. 14 is a side view showing a state in which the insulator of FIG. 10 is attached to the fixed contact.

As shown in FIG. 10, the insulator 14 in this embodiment is provided with a groove 15 extending from the load-side end surface of the side wall 14a to the front of the power-source-side end surface. The groove 15 is formed in the arrow direction from the load side. As shown in FIG. 14, the grid 2 inserted in is fixed with its end face pressed by the insulating partition wall 22 mounted on the insulator 14. The insulating partition wall 22 is mounted in place of the shield wall 14e formed integrally with the insulator 14 in FIG. 7, prevents the arc gas generated in the insulator 14 from moving to the opening / closing mechanism portion, and protects the arc gas in the arc gas. Prevents malfunction of the switching mechanism and deterioration of insulation strength due to adhesion of contact melts.

In FIG. 12, an insulating partition wall 22 integrally molded from an arc-resistant resin such as polyester is formed with a flat partition wall body 22a having slits 23 along the moving path of the movable contact 1 (FIG. 3). , A reverse U-shaped contact cover 22b that covers the folded-back portion of the fixed contact 5 (FIG. 14). And the slit 23 is formed in the partition body 22a.
Tongue-shaped pressing pieces 22c for pressing the grid 2 are vertically arranged on both sides of the grid by a U-shaped cut, and a pair of left and right protrusions 22d to be fitted to the insulator 14 is formed on the outer side thereof as described later. There is. Further, the contact cover 22b
A pair of left and right hooks 22e that fit into the insulator 14 are provided on both sides of the hook, as will be described later. Holding piece 22c
At each tip of the pressing protrusions 2 whose projecting height gradually increases from top to bottom in accordance with the end face positions of the grids 2 stacked one above the other.
2f is provided.

The insulating partition 22 is fitted into the insulator 14 in which the grid 2 is inserted from the bottom thereof. That is, as shown in FIG. 11, a slit 14h is formed on the wall of the recess 17 of the insulator 14 on the load side (right side in the drawing) in accordance with the hook 22e of the insulating partition wall 22, and the engaging stepped portion 14g is formed in this portion. Has been formed. Therefore, the contact cover 22b of the insulating partition wall 22 is provided in the space 24 between the side walls 14a of the insulator 14.
The bottom of the hook 22e is aligned with the slit 14h, and the insulating partition 22 is pushed into the insulator 14 from the bottom to the top. Meanwhile, the protrusion 22d of the partition body 22a of the insulating partition 22 interferes with the end face of the side wall 14a.
4 is elastically curved and deformed as shown by the chain line, but when the projection 22d eventually reaches a recess (not shown) provided on the end surface of the side wall 14a, the projection 22d is fitted into the insulation partition wall. 22 is attached as shown by the solid line in FIG. In this state, the pressing projections 22f of the insulating partition walls 22 press the end faces of the grids 2 to fix them.

On the other hand, referring to FIG. 13, the protective plate 21 in this embodiment has a pair of upper and lower tongue-shaped valve bodies 21i formed by H-shaped notches 25, and a mounting portion 21j having a V-shaped cross section is provided on the lower portion. Has been. On the other hand, in FIG. 10, the insulator 14 is provided with a slit-shaped mounting hole 26 in the connecting portion 14c corresponding to the mounting portion 21j of the protective plate 21 so as to penetrate back and forth, and the side wall 14a on the power source side. A mounting groove 27 is provided at the upper part of the end face so as to fit to the left and right shoulders 21k at the upper end of the protective plate 21. Therefore, the protective plate 21 is inserted by inserting the upper end shoulder portion 21k into the mounting groove 27 from below and then inserting the mounting portion 21j into the mounting hole 26 from the front.
As shown in FIG. Although not shown, an engaging projection is provided on the lower edge of the mounting hole 26, and the mounting portion 21j inserted into the mounting hole 26 has the engaging hole 28 fitted into the engaging projection and locked.

When the current is cut off, the protective plate 21 pushes the valve body 21j as shown by the chain line in FIG. 13B by the rise of the internal pressure of the insulator 14 to discharge the arc gas. Here, as shown in FIG. 11, the space 24 between the side walls 14a of the insulator 14 is widened in a V shape from the vicinity of the fixed contact 7 toward the power supply side. According to such a configuration, the arc gas is likely to swell toward the power supply side, so that the arc generated on the fixed contact 7 is promoted to move to the power supply side by the pressure of the arc gas, and the residence time on the fixed contact 7 is increased. Since the length is shortened, the fixed contact 7 is less consumed. As shown in FIG. 14, the insulating body 14 on which the protective plate 21 and the insulating partition wall 22 are mounted is fitted into the magnetically driven iron core 13 via the recessed portion 17, as shown in FIG. In FIG. 14, the magnetically driven iron core 13 used is the arc horn integrated type shown in FIG.

Although the above-mentioned embodiment is for the circuit breaker having the magnetically driven iron core 13, the embodiment in which the structure in which the grid is supported by the insulating material of the mold resin is applied to the circuit breaker having no magnetically driven iron core is described. This is shown in FIGS. 15 and 16. Here, FIG. 15 is a perspective view of the movable / fixed contact portion in a state where the insulator and the grid are vertically broken.
FIG. 4 is an exploded perspective view of a main part. This embodiment has substantially the same construction as that of the embodiment shown in FIGS. 1 and 2 except that there is no magnetically driven iron core. However, in this case, the lower end surface of the side wall 14a of the insulator 14 is the main portion 5 of the fixed contactor 5.
As shown in FIG. 16, a gas vent valve 30 is provided on the protective plate 29 that is supported in contact with the upper surface of b and also serves to hold down the grid 2. Furthermore, in this case, the portion of the groove 15 where the leg portion 2a of the grid 2 is accommodated is the side wall 14a.
The inside of is closed so that the leg 2a is completely shielded from the arc.

In FIG. 16, the protective plate 29 is integrally molded from a resin such as nylon having flexibility and strong arc resistance, and is a front plate 29a, side plates 29b on both sides of the front plate 29a, and a top plate extending between the upper ends thereof. 29c, an upper hook 29d is formed on an extension of the upper plate 29c, and the front plate 29c is formed.
A lower hook 29e is formed on the extension of a. The degassing valve 30 includes a pair of valve bodies 30 which are vertically opened in the front plate 29a through an H-shaped slit similar to that shown in FIG.
a is integrally formed, and when the current is cut off, the valve body 30a is elastically deformed by the gas pressure as shown by the chain line to discharge the arc gas. The lower plate 29e of the protective plate 29 is inserted into the mounting hole 26 of the insulator 14 and is locked by an engaging protrusion (not shown), and then the upper hook 29d is locked by the engaging step 14f and mounted. In this mounted state, the side plate 29b of the protective plate 29 faces the end of the groove 15 and presses the grid 2.

By the way, when the current is cut off, I ² t (I: passing current, t: arc time) and arc power A _P (product of passing current and arc voltage), which have already been described, are the same as those of the insulator 1.
4 is influenced by the gap G between the side walls 14a (see FIG. 15). The diagram of FIG. 18 schematically shows the relationship with 100% when G = 8 mm. In the figure, I ² t decreases as the side wall spacing G decreases, and conversely A _P
Will increase. This is because when the side wall spacing G becomes smaller, the insulator 1
While the space inside 4 decreases, the arc and the side wall 14a approach each other, the amount of gas generated from the insulator 14 increases, and the functions of both narrowing and cooling of the arc increase, and the current I decreases, while the arc voltage decreases. Is to rise above that. That is, the smaller the side wall spacing G, the more improved the arc extinguishing performance.
However, when the arc power A _P increases, the internal pressure of the circuit breaker rises accordingly, and the load force on the case and cover increases, and there is a risk of damaging the same. Therefore, it is necessary to properly set the side wall distance G in consideration of the breaking capacity of the circuit breaker and the strength of the case and the cover.

FIG. 17 shows an embodiment in which an auxiliary side wall 31 is attached to the insulator 14 so that the side wall gap G can be easily adjusted. The auxiliary side wall 31 is formed of the same molding resin as that of the insulator 14, and includes a pair of left and right upright side walls 31a and a horizontal connecting plate 31b that connects the side walls 31a at the lower part of the opening / closing mechanism side (right side in FIG. 17). Side wall 31
A hook 31c is provided at the upper end of a. Auxiliary side wall 31
Is inserted into the insulator 14 from below as shown, and the hook 31c is attached by engaging with a recess (not shown) in the upper inside portion of the side wall 14a. When the insulator 14 to which the auxiliary side wall 31 is attached is attached to the fixed contactor 5, the connecting plate 31b of the auxiliary side wall 31 contacts the upper surface of the folded end 5a of the fixed contactor 5. According to such a configuration, the side wall 3
By mounting the auxiliary side wall 31 with the gap G of 1a changed, the optimum side wall gap G can be obtained according to the required performance of each circuit breaker and the strength of the case or cover using one type of insulator 14. Can be set.

[0047]

As described above, according to the present invention, the following effects can be obtained. (1) The support plate of the grid and the insulating member of the magnetically driven iron core are integrated to simplify the structure and facilitate assembly work and parts management. (2) Since the insulator made of the mold resin can have a sufficient thickness of the side wall, it is possible to protect the grid from the arc by deepening the groove and putting the grid therein. In particular, if an overhanging portion that covers the grid is integrally formed around the groove, it is possible to completely prevent damage to the grid due to an arc by eliminating the exposed surface of the grid. (3) The grid can be fixed simply by pressing it into the groove, and no bonding or caulking is required, so the number of assembly steps can be reduced. (4) Since the inner space of the insulator supporting the grid is closed, the internal pressure rises significantly when the current is interrupted, and the arc voltage rises greatly due to the arc narrowing action, resulting in excellent interrupting performance. (5) Since the rise in internal pressure when the current is cut off is received by the insulator, the pressure load on the mold case is reduced and the pressure resistance design condition is relaxed. (6) By making the side wall thickness of the insulator large, the insulator and the arc can be brought close to each other to generate a large amount of arc-extinguishing gas from the insulator, thereby enhancing the cooling effect of the arc. (7) Except for the moving path of the movable contact, a shield wall that blocks the side walls is integrally formed at the end of the insulator on the opening / closing mechanism side, and a shield plate is attached to the opposite end to increase the internal pressure. It becomes remarkable, and the arc extinguishing action due to the narrowing down of the arc is further enhanced. (8) The grid can be inserted into the insulator from either the power supply side or the load side, but when it is inserted from the power supply side, it is inserted with the protective plate attached to the insulator and from the load side. In this case, similarly, by pressing the grid with the insulating partition wall to ensure the fixation, it is possible to effectively suppress the vibration of the grid due to the alternating magnetic field. (9) If the width of the space between the side walls of the insulator is widened from the vicinity of the fixed contact toward the power supply side in a V shape, the movement of the arc toward the power supply side due to the pressure of the arc gas is promoted, and the arc residence time is shortened. Wear of fixed contacts is reduced. (10) By installing auxiliary side walls inside the left and right side walls of the insulator, the width of the inner space of the insulator is set appropriately according to the required performance of each circuit breaker and the strength of the case and cover. It will be easy.

[Brief description of drawings]

FIG. 1 is a perspective view of an insulator portion in which a main portion is broken, showing an embodiment of the present invention.

FIG. 2 is an exploded perspective view of an insulator and a grid shown in FIG.

FIG. 3 is a perspective view of a movable / fixed contactor portion in FIG.

FIG. 4 is a perspective view of an essential part seen from the inside of an insulator side wall showing a different embodiment of the present invention.

FIG. 5 is a perspective view of a grid showing still another embodiment of the present invention.

FIG. 6 is a perspective view of a magnetically driven iron core showing still another embodiment of the present invention.

FIG. 7 shows still another embodiment of the present invention, (A) is a front view of an insulator, and (B) is a longitudinal sectional view thereof.

FIG. 8 shows still another embodiment of the present invention, (A) is a front view of an insulator, and (B) is a side view thereof.

FIG. 9 shows a protective plate attached to the insulator of FIG. 8, (A)
Is a front view and (B) is a side view thereof.

FIG. 10 is an exploded perspective view of an insulator and a grid showing still another embodiment of the present invention.

11 is a bottom view of the insulator of FIG. 10.

FIG. 12 shows an insulating partition attached to the insulator of FIG.
(A) is a front view, (B) is a sectional view taken along line BB,
(C) is a rear view thereof, and (D) is a plan view of (B).

13 shows a protective plate attached to the insulator of FIG. 10,
(A) is a front view and (B) is a side view thereof.

14 is a side view of the fixed contactor to which the insulator of FIG. 10 is attached.

FIG. 15 is a perspective view of an insulator part in which a main part is broken, showing still another embodiment of the present invention.

16 is an exploded perspective view of FIG. 15.

FIG. 17 is a perspective view of an insulating body and an auxiliary side wall attached to the insulating body according to still another embodiment of the present invention.

18 is a diagram schematically showing the relationship between the sidewall spacing G of the insulator in FIG. 15, I ² t, and the arc power A _P.

FIG. 19 is a perspective view of an arc extinguishing device showing a conventional example.

20 is a vertical cross-sectional view of a power supply side half of a conventional circuit breaker including the arc extinguishing device of FIG. 19.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 movable contact 2 grid 4 power supply side terminal 5 fixed contact 7 fixed contact 9 arc horn 13 magnetic drive iron core 14 insulator 14a side wall 14d overhanging portion 14e shielding wall 15 groove 17 recess 20 shielding plate 21 protective plate 22 insulating partition wall 29 Protective plate 30 Gas vent valve 31 Auxiliary side wall

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsunori Kuboyama 1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture Fuji Electric Co., Ltd. No. 1 inside Fuji Electric Co., Ltd.

Claims (9)

[Claims] 1. An arc-extinguishing device having a grid in which U-shaped ends of fixed contacts provided with fixed contacts are folded back along the movable contacts and the movable and fixed contacts are provided. In a circuit breaker arranged around the child, an insulator having a pair of left and right side walls connected to each other is provided by integral molding of a molding resin, and a multi-step groove formed on the facing surface of the side wall of the insulator. Circuit breakers, each with a grid inserted. 2. An end portion of a fixed contact provided with a fixed contact is folded back in a U-shape along a movable contact, and a U-shaped magnetic drive iron core is attached to this folded back end, and a multi-stage structure is provided. In a circuit breaker in which an arc extinguishing device having a stacked grid is arranged surrounding the movable / fixed contact, an insulator having a pair of left and right side walls connected to each other is provided by integral molding of a molding resin. The grid was inserted into the groove formed in multiple steps on the opposite surface of the side wall of the insulator, and the insulator was fitted on the leg portion of the magnetic drive core through the recess formed on the bottom surface of the side wall. Characteristic circuit breaker. 3. The circuit breaker according to claim 1, wherein an overhanging portion which covers the grid inserted into the groove is integrally formed around the groove on the side wall of the insulator. 4. The shield wall for closing between the side walls except for the moving path of the movable contact is integrally formed at the end of the insulator on the side of the opening / closing mechanism. The circuit breaker described in 1. 5. A groove for inserting a grid is formed from an end surface on a power source side of an insulator to a front surface of an end surface on a load side, and the grid inserted in the groove is pressed by a protective plate attached to the insulator. It fixed, The circuit breaker in any one of Claims 1-4. 6. A circuit breaker according to claim 5, wherein the protective plate is provided with a gas vent valve for discharging arc gas generated when the current is cut off by elastic deformation of the valve body. 7. A groove for inserting a grid is formed from a load side end surface of a side wall of an insulator to a front side of a power source side end surface, and the grid inserted in the groove is pressed by an insulating partition attached to the insulator. The circuit breaker according to any one of claims 1 to 3, which is fixed. 8. The circuit breaker according to claim 1, wherein the width of the space between the side walls of the insulator is widened from the vicinity of the fixed contact toward the power source side in a V shape. vessel. 9. The circuit breaker according to claim 1, wherein auxiliary side walls for adjusting the distance between the side walls are mounted inside the left and right side walls of the insulator.