JP3147179B2 - 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 such as a circuit breaker or an earth leakage breaker, and more particularly to a reinforcing means for a case made of a molded resin.

[0002]

2. Description of the Related Art FIGS. 6 and 7 show a conventional structure.
FIG. 6 is a longitudinal sectional view of an essential part showing a power supply side end of the circuit breaker, and FIG. 7 is a perspective view of an essential part of the case. In the figure, reference numeral 1 denotes a case, and 2 denotes a cover which covers the upper surface thereof, both of which are molded from a mold resin. Case 1 has left and right side walls 3
(Figure 7) between is divided into a space for three phases with a partition wall, not shown, each of the spaces to be opened and closed portions of each phase consisting <br/> the fixed contact 4 and the movable contactor 5 is housed I have.

Here, when a large current such as a short-circuit current flows and the circuit breaker trips and the movable contact 5 is separated from the fixed contact 4, an arc is generated between the contacts and the case 1
Internal pressure rises. Therefore, the side wall 3 of the case 1 tends to open outward, but if the internal pressure becomes excessive, the case 1 may be cracked. Therefore, in a high-performance circuit breaker, a rib 6 is integrally formed between the side wall 3 and a not-shown partition wall near the opening / closing portion as shown in the figure, or compression molding is adopted as a molding method. 1 is reinforced.

[0004]

However, the method of providing the rib 6 has the following disadvantages. That is, as the molding material for the case 1, a material that satisfies properties such as insulation, strength, and appearance in a well-balanced manner is selected.
If the ribs 6 are formed integrally with the case 1 made of such a material, the cross-sectional area becomes considerably large, which hinders an attempt to reduce the size of the circuit breaker. When the ribs 6 are to be provided, it is necessary to provide a window 7 at the bottom of the case 1 due to the mold structure. However, if the arc gas escapes from the slit 7 at the time of current interruption, there is a risk that a ground fault may occur. Silicon rubber or the like must be applied to prevent this, and a lot of time is required for application and drying. On the other hand, when the molding method is compression molding, the molding cycle is longer than that of ordinary injection molding, the equipment is large, and the cost is high.
The present invention has been made under such circumstances, and provides a circuit breaker that does not require a large reinforcing space and that can obtain sufficient reinforcing strength of a case without using compression molding. It is intended for.

[0005]

In order to achieve the above object, the present invention provides a case and a cover made of a molded resin.
And the case has a partition between the left and right side walls.
It is divided into space for each phase, and the opening and closing part of each phase is
In housed the circuit breaker, the mating surfaces of the cover <br/> over of the case, transverse to said case through said septum
The groove cross-sectional form, see write fitted to left and right <br/> beams of the resin molded article which engages the side wall at both ends in the groove is the case, before the beam
It should be held down by the cover (claim 1) . The beam can be provided with a slit for inserting the shielding plate of each phase extinction chamber (claim 2) . In addition, the beam and the case
The engagement surface of the side wall of the can to increase the strength of the engaging portion by a slope (claim 3).

[0006]

By engaging both ends with the case side wall at the joint with the case cover and fitting the beam into place, the case side wall which is to be opened outward by the internal pressure can be restrained to suppress deformation. The beam is fixed with a cover. In this case, since the beam is formed as a separate member from the case, the material can be selected mainly based on the strength characteristics. Therefore, by using a material having high strength, it is possible to reduce the required area by reducing the cross-sectional area. Also,
When the rib is integrally formed with the case, a window required for the mold structure is not required.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 is an exploded perspective view, FIG. 2A is a plan view of the beam in FIG. 1, FIG. 2B is a front view thereof, FIG. 3 is a sectional view taken along line III-III in FIG. Is a vertical cross-sectional view of a main part showing a power supply side end of the circuit breaker provided with the case of FIG. 1, and FIG. 5 is a horizontal cross-sectional view of another main part showing another embodiment of an engaging portion between a beam and a case side wall. . In FIGS. 1 and 3, the shape of the case 1 is simplified as far as it does not disturb the understanding of the present invention. Further, the same reference numerals are used for the portions corresponding to the conventional example.

First, in FIGS. 1 and 2, the case 1 is divided into spaces for three phases by partition walls 8 between the left and right side walls 3.
In these spaces, the opening and closing parts of each phase are accommodated. The cover 2 also faces the walls 3 and 8 of the case 1 .
Case 1 with a corresponding wall
Overlaid.

In the vicinity of the opening and closing portions of the walls 3 and 8 of the case 1, a rectangular groove 9 is formed in a straight line so as to penetrate the partition 8 and cross the case 1 from the joint with the cover 2. In particular, the protrusions 10 are provided by removing the grooves 9 of the left and right side walls 3 from the bottom outside in a stepwise manner. Reference numeral 11 denotes a beam of a resin molded product to be fitted into the groove 9, and protrusions 10 are provided at both ends of a square bar having the same cross section as the groove 9.
And a projection 12 is provided in a hook shape. And
A slit 13 is provided at a position corresponding to each phase, into which a shield plate of an arc-extinguishing chamber described later is inserted.

FIG. 3 shows a state in which the beam 11 is fitted into the groove 9 of the case 1 and the cover 2 is mounted. Case 1
The protrusions 10 and the protrusions 12 of the beams 11 are engaged with each other so that they are alternately arranged.
And is pressed against the cover 2. The side surface of the beam 11 coincides with the side surface of the case 1. In FIG. 4, reference numeral 14 denotes an arc-extinguishing chamber surrounding the fixed contactor 4 and the movable contactor 5, and reference numeral 15 denotes a shielding plate for covering the arc-extinguishing chamber 14 so that foreign matter does not enter from the arc gas discharge side. The shielding plate 15 is inserted into a groove (not shown) provided in the case 1, but is also inserted into the slit 13 of the beam 11 to hold an intermediate portion thereof.

According to the above configuration, even when the internal pressure of the case 1 rises and the side wall 3 tries to open at the time of shutoff, the deformation is suppressed due to the presence of the beam 11, and no damage such as a crack occurs. Moreover, since the beam 11 is formed as a separate member from the case 1, a material having high strength can be freely selected without being restricted by the material of the case 1, and as a result, the cross-sectional area can be reduced. Does not hinder.
Further, the mold structure is simpler than the case where the reinforcing member is integrally formed with the case 1, and the window 7 (FIG. 6) at the bottom of the case, which is required in that case, becomes unnecessary, and the work of applying silicon rubber or the like is also eliminated. . Further, the shielding plate 15 also tends to come off due to the internal pressure, but since it is inserted into the slit 13 of the beam 11 and holds the intermediate portion, it is less likely to come off than when it is simply inserted into the groove of the case 1. .

FIG. 5 shows an embodiment in which an engagement surface of the projection 10 of the case side wall 3 and the projection 12 of the beam 11 is inclined at an angle θ. By providing such an inclination, the direction of the shearing force F acting between the projections 10 and 12 is inclined by the angle θ,
The shear area increases and the strength of the engaging portion increases.

[0013]

According to the present invention, the beam for suppressing the opening of the case due to the internal pressure is formed as a separate member from the case, and this is fitted and mounted. It can be used to reduce the cross-sectional area, reduce the space required for reinforcement, and downsize the circuit breaker. At the same time, the mold structure for forming the case is simplified, and the work of applying silicon rubber or the like for preventing a ground fault is eliminated.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the present invention.

2A is a plan view of a beam in FIG. 1, and FIG. 2B is a front view thereof.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a vertical sectional view of a main part of a circuit breaker provided with the case of FIG. 1;

FIG. 5 is a cross-sectional view of a main part showing another embodiment of the engaging portion between the case and the beam.

FIG. 6 is a longitudinal sectional view of a main part of a circuit breaker showing a conventional example.

FIG. 7 is an enlarged perspective view of a main part of the case in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case 2 Cover 3 Side wall 11 Beam 13 Slit 15 Shield plate

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP 3-19234 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01H 71/02

Claims (3)

(57) [Claims] 1. A case and a cover made of a mold resin.
In the case, the partition between the left and right side walls is separated by a partition.
The opening and closing parts of each phase are accommodated in these spaces
In the circuit breaker that is, the mating surface of said cover of said case, said case
Wherein a groove traversing through the partition wall, viewed write fitted <br/> beams of the resin molded article in which both ends are engaged with the left and right side walls of the casing in the groove, pressing the beam in the cover A circuit breaker characterized by that: 2. A circuit breaker according to claim 1, wherein said beam is provided with a slit for inserting a shield plate of each phase extinguishing chamber. 3. A circuit breaker according to claim 1 or claim 2, wherein in that the engagement surface of the inclined surface of the side wall of said beam and said case.