JP2834903B2 - Circuit breaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker in which a main body of a circuit breaker is housed in a molded case, such as a circuit breaker for low-voltage wiring.

[0002]

2. Description of the Related Art FIG. 9 is, for example, "Distribution Board / Control Board Handbook" (January 1, 1979, Denki Shoin), pp. 6-11.
It is principal part sectional drawing of the conventional circuit breaker shown on page 6,
This shows a state where a large current flows due to a short circuit or the like and the battery is opened. In the figure, 1 is a mold case, 2 is a fixed contact fixed in the mold case 1, 3 is a fixed contact fixed to the fixed contact 2, 4 is a mold case 1
The movable contact 5, which is rotatably provided therein, is fixed to the movable contact 4, and is a movable contact that comes into contact with and separates from the fixed contact 3 by the rotation of the movable contact 4. The breaker body 6 includes a mechanism (not shown) for moving the fixed contact 2, the movable contact 4, and the contacts 3 and 5 apart, and an arc extinguishing unit (not shown) for extinguishing the arc 7. have.

Next, the operation will be described. When a short circuit occurs in a circuit located on the load side of the circuit breaker and a large current flows through the circuit breaker, the movable contact 4 is rotated by the mechanism and the movable contact 5 is separated from the fixed contact 3. I do. At this time, an extremely large pressure is applied to the mold case 1 by the arc 7 generated between the two contacts 3 and 5. On the other hand, when the rated breaking capacity is cut off, the mold case 1 is designed so as to have sufficient strength, so that the mold case 1 does not crack. But,
When the same circuit breaker cuts off a high breaking capacity exceeding the rated breaking capacity, cracks occur in the mold case 1.

[0004]

In recent years, the short-circuit capacity has increased due to an increase in power supply capacity, and it has become necessary to use a circuit breaker having a very large breaking capacity. In the conventional circuit breaker as described above, it is necessary to increase the wall thickness of the mold case 1 in order to increase the breaking capacity and withstand the internal pressure due to the arc at the time of breaking. As a result, the mold for the mold case 1 must be newly manufactured.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. Even when the breaking capacity is increased, the mold case can be formed without increasing the thickness of the mold case. An object of the present invention is to provide a circuit breaker that can prevent occurrence of cracks.

[0006]

According to a first aspect of the present invention, there is provided a circuit breaker in which a metal reinforcing plate is closely attached to a side surface of a mold case, and an insulator is provided on an outer peripheral portion of the metal reinforcing plate. is there. In the circuit breaker according to the second aspect of the present invention, a holding member facing the side surface of the mold case is attached to the mold case, a metal reinforcing plate is provided between the holding member and the mold case, and screwed to the holding member. The metal reinforcing plate is pressed by the tip of the screw and brought into close contact with the side surface of the mold case.

[0007]

According to the first aspect of the present invention, the mold case is reinforced by the metal reinforcing plate to prevent the mold case from cracking due to the arc pressure, and the metal reinforcing plate is covered with an insulating material, so that the metal reinforcing plate has an insulating property. To secure. According to the second aspect of the present invention, the degree of adhesion of the metal reinforcing plate to the mold case is increased by bringing the metal reinforcing plate into close contact with the side surface of the mold case with a screw screwed to the holding metal.

[0008]

EXAMPLES A description is given of a preferred embodiment of the present invention. FIG. 1 is a side view showing a circuit breaker according to a first embodiment of the present invention, and FIG. 2 is a sectional view taken along the line II-II in FIG. 1, and the same or corresponding parts as those in FIG. And description thereof is omitted. In the figure, reference numeral 8 denotes a metal reinforcing plate having an L-shaped cross section which is in close contact with the side surface of the mold case 1;
The metal reinforcing plate 8 is fixed to the bottom surface of the mold case 1 with screws 9. Further, two metal reinforcing plates 8 are provided so as to cover both side surfaces of the mold case 1. The material of the metal reinforcing plate 8 may be a normal iron plate or the like as long as sufficient strength can be obtained.

In the circuit breaker configured as described above, since the metal reinforcing plate 8 is in close contact with the side surface of the mold case 1, the same effect as increasing the thickness of the mold case 1 is obtained. , The strength of the case increases. Therefore, even if the breaking capacity becomes large and a large arc pressure is applied to the mold case 1, cracking of the mold case 1 is prevented.

As shown in FIG. 3 (second embodiment) , in order to increase the adhesion between the metal reinforcing plate 8 and the mold case 1, an insulating material is provided between the metal reinforcing plate 8 and the mold case 1. Alternatively, a non-insulating plate 10 may be interposed. In the above embodiment, to fix the L-shaped cross section of the metal reinforcing plate 8 to the bottom surface of the molded case 1, for example, as shown in FIG. 4 (third embodiment), the mold case the flat metal reinforcing plate 8 Alternatively, it may be directly screwed to the side surface portion 1 and closely attached. Further, both sides of the mold case 1 may be covered with one metal reinforcing plate 8 having a U-shaped cross section.

FIG. 5 is a sectional view of a main part of a circuit breaker according to a fourth embodiment of the present invention. In the figure, reference numeral 11 denotes a plate-shaped insulator covering the outer peripheral portion of the metal reinforcing plate 8 on the side not in contact with the mold case 1;
For example, it is made of an insulating resin material and is molded on the metal reinforcing plate 8.

In the circuit breaker of this embodiment, similarly to the circuit breaker of FIG. 2, the metal reinforcing plate 8 prevents the mold case 1 from cracking due to arc pressure. In addition, the electrical insulation of the metal reinforcing plate 8 is enhanced by the insulator 11. Thereby, a short circuit between the arc gas (not shown) discharged from the inside of the mold case 1 and the metal reinforcing plate 8 is prevented.

As shown in FIG. 3, the metal reinforcing plate 8
A plate 10 can be interposed between the mold case 1 and FIG.
It is needless to say that the plate-shaped metal reinforcing plate 8 may be directly fixed to the side surface of the mold case 1 as shown in FIG.

FIG. 6 is a side view showing a circuit breaker according to a fifth embodiment of the present invention, FIG. 7 is a sectional view taken along line VII-VII of FIG. 6, and FIG. 8 is an exploded perspective view of FIG. FIG. In the figure, 12 is a bracket mounting screw on the bottom of the mold case 1.
13 is a holding member having an L-shaped cross-section, comprising a portion attached by 13 and a portion facing the side surface of the mold case 1. A flat metal reinforcing plate 8 is provided. Reference numeral 14 denotes a plurality of pressing screws which are screwed to the holding bracket 12, and the tips of the pressing screws 14 are in contact with the metal reinforcing plate 8, respectively. Further, the metal reinforcing plate 8 is moved by the thrust of these pressing screws 14 to the mold case 1.
It is in close contact with the side surface. The outer peripheral portion of the holding member 12 is covered with the insulator 11.

In the circuit breaker constructed as described above, similarly to the circuit breaker shown in FIG. 2, the metal reinforcing plate 8 prevents the mold case 1 from being cracked due to the arc pressure, and the insulator 11 allows the circuit breaker shown in FIG. As in the case of the first embodiment, a short circuit between the metal reinforcing plate 8 or the holding metal 12 and the arc gas is prevented. Further, in the circuit breaker of this embodiment, since the degree of adhesion of the metal reinforcing plate 8 to the side surface of the mold case 1 is increased by tightening the pressing screw 14, the mold case 1 Cracks are more reliably prevented.

A plate 10 as shown in FIG. 3 is interposed between the metal reinforcing plate 8 and the side surface of the mold case 1, or an insulating plating such as Zn plating is applied to the metal reinforcing plate 8 and the holding bracket 12. Needless to say, it may be performed. Also,
The holding metal 12 only needs to be able to press the metal reinforcing plate 8 against the side surface of the mold case 1 via the pressing screw 14, and the shape is not limited to the above embodiment.

[0017]

As described above, in the circuit breaker according to the first aspect of the present invention, since the mold case is reinforced by the metal reinforcing plate, even when the breaking capacity is increased, the thickness of the mold case is increased. Therefore, it is possible to prevent the occurrence of cracks in the mold case, to reduce the size of the whole, and to improve the reliability. Further, since the metallic reinforcing plate covered with an insulator, enhance the insulating metallic reinforcing plate, Morudoke
Between the arc gas discharged from the base and the metal reinforcing plate.
Even so the effect of being able to you to prevent a short circuit. Further, in the circuit breaker according to the second aspect of the present invention, since the metal reinforcing plate is pressed by the tip of the screw screwed to the holding member and is brought into close contact with the side surface of the mold case, The degree of adhesion of the metal reinforcing plate to
In addition to the effect of the first aspect of the present invention, there is an effect that cracking of the mold case due to arc pressure can be more reliably prevented.

[Brief description of the drawings]

FIG. 1 is a side view showing a circuit breaker according to one embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a sectional view of a main part of a circuit breaker according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a main part of a circuit breaker according to a third embodiment of the present invention.

FIG. 5 is a sectional view of a main part of a circuit breaker according to a fourth embodiment of the present invention.

FIG. 6 is a side view showing a circuit breaker according to a fifth embodiment of the present invention.

FIG. 7 is a sectional view taken along the line VII-VII in FIG. 6;

FIG. 8 is an exploded perspective view of FIG.

FIG. 9 is a sectional view of a main part of an example of a conventional circuit breaker.

[Description of Signs ] 1 Mold case, 6 Breaker body, 8 Metal reinforcement
Plate, 11 insulator, 12 holding bracket, 14 pressing screw
Ji).

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinji Yamagata 1-8 Midoricho, Fukuyama City Mitsubishi Electric Corporation Fukuyama Works (56) References Japanese Utility Model 1987-173116 (JP, U) (58) Field surveyed (Int.Cl. ⁶ , DB name) H01H 33/53 H01H 9/02 H01H 33/02

Claims (2)

(57) [Claims] 1. A mold case accommodating a circuit breaker body, a metal reinforcing plate closely attached to a side surface of the mold case, and an insulator provided on an outer peripheral portion of the metal reinforcing plate. A circuit breaker, comprising: 2. A mold case accommodating a circuit breaker main body, a retainer attached to the mold case so as to face a side surface of the mold case, and a retainer provided between the retainer and the mold case. And a metal reinforcing plate pressed by a tip end of a screw screwed into the holding member and closely attached to a side surface of the mold case.