JPH03129612A - Outer case for circuit breaker - Google Patents

Abstract

PURPOSE:To prevent the outer case from being broken at the time of breaking for short circuit with a simple means by specifying the horizontal gap at the faucet joint between the case and a cover. CONSTITUTION:A faucet joint portion 7 is provided on the mating surfaces of a side wall 3 of a case 1 and a side wall 4 of a cover 2, where an inside located projection 3a of the case 1 and an outside located projection 4a of the cover 2 fit to each other. The horizontal gap in the faucet joint is made to be 0.3mm which is greater than in the conventional practice. With this constitution, the side wall 3 deforms within the range not to reach the breakage and then butts against the cover 2. The internal pressure due to arc energy produced by circuit breaking receives a cushion effect.

Description

【発明の詳細な説明】[Detailed description of the invention] 【産業上の利用分野】[Industrial application field]

この発明は、配線用遮断器などの小型の回路遮断器の外
箱に関する。The present invention relates to an outer box for a small circuit breaker such as a molded circuit breaker.

【従来の技術】[Conventional technology]

第４図は３極回路遮断器の外箱の一般的な構成を示す概
略横断面図である。図において、■はモールド樹脂から
なるケース、２は同じくカバーで、いずれも左右の側壁
３．４及び相間隔壁５，６により各相の遮断空間に区画
されている。ケース１とカバー２の側壁３と４との合わ
せ面には、遮断時に発生するアークガスの側面からの噴
出の防止と組立上の位置決め作用を目的として、互いに
いんろう式に嵌まり合う掛け合い部７が設けられている
。また、相間隔壁５と６との合わせ面には、アークガス
による相間短絡の防止とやはり組立上の位置決め作用を
目的として、凹凸の組み合わせによる嵌め合い部８が設
けられている。 このような構造の外箱において、掛け合い部７あるいは
嵌め合い部８では、ケース１と掛け合い部２との間に横
方向（図の左右方向）にいくらかの隙間が当然生じるが
、この隙間はケース１あるいはカバー２の成形上の寸法
精度から許される範囲内でできるだけ小さくして、ケー
ス１とカバー２の組み合わせをなるべく緊密にするよう
にしていた。具体的には、掛け合い部７の図示隙間ａは
、０．１ｍから０．３ｎ＋ｎ＋程度までに抑えられてい
た。FIG. 4 is a schematic cross-sectional view showing the general structure of the outer case of a three-pole circuit breaker. In the figure, ``■'' is a case made of molded resin, and 2 is a cover, both of which are divided into isolation spaces for each phase by left and right side walls 3.4 and interphase walls 5, 6. At the mating surfaces of the case 1 and the side walls 3 and 4 of the cover 2, there is a hooking part 7 that is fitted into each other in a swivel manner for the purpose of preventing the arc gas generated from being ejected from the side surface when shutting off and for positioning during assembly. is provided. Further, on the mating surfaces of the phase separation walls 5 and 6, a fitting portion 8 made of a combination of concave and convex portions is provided for the purpose of preventing short circuits between the phases due to arc gas and also for positioning during assembly. In an outer box having such a structure, some gap naturally occurs in the horizontal direction (left and right direction in the figure) between the case 1 and the engagement part 2 at the engaging part 7 or the fitting part 8, but this gap is The case 1 and the cover 2 are made as small as possible within the range allowed by the dimensional accuracy in molding the case 1 and the cover 2, and the combination of the case 1 and the cover 2 is made as tight as possible. Specifically, the illustrated gap a of the interlocking portion 7 was suppressed to about 0.1 m to 0.3n+n+.

【発明が解決しようとする課題】[Problem to be solved by the invention]

ところが、このような従来の回路遮断器の外箱は、短絡
電流を遮断した場合の内圧の上昇により、ケースあるい
はカバーが破壊することがあった。 この対策としては、材質の変更、肉厚寸法の増大、形状
の改善などが考えられるが、これらはいずれもコストア
ップを伴い、また外形寸法や内部構造には種々の制約が
あって設計変更は必ずしも容易ではない。 そこで、この発明は安価で簡単な手段により短絡遮断時
の破壊を防止した回路遮断器の外箱を提供することを目
的とするものである。However, in the outer case of such a conventional circuit breaker, the case or cover may be destroyed due to an increase in internal pressure when the short circuit current is interrupted. Possible countermeasures include changing the material, increasing the wall thickness, and improving the shape, but all of these involve increased costs, and there are various restrictions on external dimensions and internal structure, making it difficult to change the design. It's not always easy. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an outer case for a circuit breaker which can be prevented from being destroyed during a short circuit by a simple and inexpensive means.

【課題を解決するための手段】[Means to solve the problem]

発明者等は短絡遮断時の内圧の上昇により外箱が破壊す
る際の現象を子細に観察した結果、ケースとカバーの側
壁の掛け合い部にある程度以上の遊びを設けることが、
破壊防止に有効であることを見出した。 すなわち、この発明は、モールド樹脂のケースとカバー
とからなり、これらの側壁の合わせ面に互いにいんろう
式に嵌まり合う掛け合い部が設けられた回路遮断器の外
箱において、掛け合い部におけるケースとカバーの横方
向の隙間を通常の成形寸法精度で得られる０、３ｍｍを
超えて、それ以上にするものである。ここで、上記隙間
の実際の値は、ケース側壁の剛性（ばね定数）を勘案し
て必要十分な大きさに定める。As a result of careful observation of the phenomenon in which the outer case is destroyed due to the increase in internal pressure during short-circuit interruption, the inventors found that it is necessary to provide a certain amount of play in the interlocking part between the side wall of the case and the cover.
It was found that this method is effective in preventing destruction. That is, the present invention provides an outer case for a circuit breaker, which is composed of a case and a cover made of molded resin, and in which a mating part is provided on the mating surfaces of these side walls to fit into each other in a self-interlocking manner. The lateral gap of the cover is made larger than the 0.3 mm that can be obtained with normal molding dimensional accuracy. Here, the actual value of the gap is determined to be a necessary and sufficient value, taking into consideration the rigidity (spring constant) of the side wall of the case.

【作　用】[For use]

回路遮断器の外箱においては、一般にケースの方がカバ
ーより高さ寸法が大きい（第４図において、Ｌ、＞Ｌ２
）ので、短絡遮断した場合の側壁の変形もケースの方が
カバーより大きい。したがって、掛け合い部の隙間ａが
小さいと、内圧によるケース側壁の外側への変形をカバ
ーがほとんどそのまま受けてしまい、カバーの側壁が破
壊し易くなる。そこで、隙間ａを適度に大きくすると、
ケース側壁は破壊に達しない範囲で変形した後にカバー
に当たり、遮断により発生したアークエネルギによる内
圧はクツション作用を受ける。すなわち、隙間ａが小さ
い場合の剛体構造が、これを大きくすることによって柔
軟構造となり、内圧の作用が和らげられて破壊が防止さ
れる。In the outer box of a circuit breaker, the case is generally larger in height than the cover (L,>L2 in Figure 4).
), the deformation of the side wall in the event of a short circuit is also greater in the case than in the cover. Therefore, if the gap a between the engaging portions is small, the cover will receive almost all the outward deformation of the case side wall due to the internal pressure, making the side wall of the cover easy to break. Therefore, if the gap a is increased appropriately,
The case side wall deforms to the extent that it does not break and then hits the cover, and the internal pressure due to the arc energy generated by the interruption is subjected to a cushioning action. That is, a rigid structure when the gap a is small becomes a flexible structure by increasing the gap a, which relieves the effect of internal pressure and prevents breakage.

【実施例】【Example】

以下、図に基づいてこの発明の詳細な説明する。なお、
対応する部分には従来例と同一の符号を付けである。 第１図はこの発明の実施例の外箱の側壁部分の横断面図
で、ケース１の側壁３とカバー２の側壁４との合わせ面
には、内側に位置するケース１の突条３ａと、外側に位
置するカバー２の突条４ａとかいんろう式に嵌まり合う
掛け合い部７が設けられ、その横方向の隙間Ａは従来よ
りも大きく、０．５〜１．５ｍｍになっている。ここで
、突条４ａは側壁４の必要な範囲にわたって連続して形
式されているが、突条３ａは外箱の前後部及びそのほぼ
中間部の３箇所に分断して形式されている。 第２図はケース１及びカバー２の内壁に沿ってそれぞれ
補強リブ９及び１０を有する形式の外箱で、この場合に
はリブ９，１０の側壁部９ａ、１０ａの合わせ面に掛け
合い部７が設けられ、その隙間Ａが従来よりも大きくな
っている。 なお、隙間Ａを大きくすることによってケースｌとカバ
ー２とを組み合わせた際の側壁３，４における位置決め
作用が弱まるが、相間隔壁５，６における嵌め合い部８
（第４図）の嵌め合いを従来と同様に密にしておけば問
題はない。 隙間Ａの大きさは、ケース側壁３の肉厚寸法や形状で決
まるばね定数を目安として決定する。第３図は上記ばね
定数を測定する方法を示したもので、図示のように側壁
３と隔壁５との間にくさび１１を圧入し、荷重Ｐ　（ｋ
ｇｆ）と変位δ（ｍｍ）とを測定して、Ｐ／δ（ｋｇｆ
／ｒＩＭ）から求めた。 第１表 第１表は定格電流１００Ａの回路遮断器について実験し
た結果を示すものである。ばね定数は同一のケースでも
部位によって異なり、直接アークに曝される電源側端部
が最も剛性が大きく設計されているので、隙間Ａも部位
によって変える必要がある。実験では電源側端部（第１
表でばね定数が４０　ｋｇｆ／ｍｍ）と負荷側端部（同
１０ｋｇｆ／肋）の２箇所でばね定数を測定し、それぞ
れ隙間Ａを変えた。 実験１は電源側端部のケース１とカバー２との掛け合い
がない場合で、短絡遮断によりケース側壁３が破壊した
。 実験２は電源側端部での隙間Ａを従来と同様の成形寸法
精度程度の０．１５ｍｍにした場合で、これはカバー側
壁４が破壊した。 実験３は電源側端部での隙間Ａを実験２の場合よりも太
きく　０．５　ｍｍにした場合で、短絡遮断をしても異
常がなかった。 実験４は肉厚の薄い負荷側端部で隙間Ａをかなり太きく
０．９ｍｍにした場合であるが、それでも短絡遮断によ
りカバー側壁４が破壊した。 実験５では負荷側端部の隙間Ａを更に大きく１゜５１１
ＩＩ１１にした場合で、短絡遮断をしても異常がなかっ
た。 以上の通り、掛け合い部７の隙間Ａをケース側壁３のば
ね定数に応じて、通常の成形寸法精度の０．３肋を超え
た大きな適正値にすることにより、従来と変わらぬ材質
、肉厚寸法、形状で短絡遮断に対応できることが確認さ
れた。Hereinafter, the present invention will be explained in detail based on the drawings. In addition,
Corresponding parts are given the same reference numerals as in the conventional example. FIG. 1 is a cross-sectional view of the side wall portion of the outer box according to the embodiment of the present invention, and the mating surface of the side wall 3 of the case 1 and the side wall 4 of the cover 2 has a protrusion 3a of the case 1 located inside. An interlocking portion 7 is provided which engages with the protrusion 4a of the cover 2 located on the outside in a pin-in type manner, and the lateral gap A thereof is larger than that of the conventional case, and is 0.5 to 1.5 mm. Here, the protrusion 4a is formed continuously over a necessary range of the side wall 4, but the protrusion 3a is formed in three parts: at the front and rear of the outer box, and approximately in the middle thereof. Fig. 2 shows an outer box having reinforcing ribs 9 and 10 along the inner walls of the case 1 and the cover 2, respectively. The gap A is larger than before. Note that by increasing the gap A, the positioning effect on the side walls 3 and 4 when the case l and cover 2 are combined is weakened, but the fitting portion 8 of the interphase walls 5 and 6 is weakened.
There is no problem if the fit shown in FIG. 4 is kept tight as in the conventional case. The size of the gap A is determined based on the spring constant determined by the thickness and shape of the case side wall 3. FIG. 3 shows a method for measuring the spring constant, in which a wedge 11 is press-fitted between the side wall 3 and the partition wall 5 as shown, and a load P (k
gf) and displacement δ (mm), and calculate P/δ (kgf
/rIM). Table 1 Table 1 shows the results of an experiment on a circuit breaker with a rated current of 100A. The spring constant varies depending on the part even in the same case, and the end on the power supply side directly exposed to the arc is designed to have the greatest rigidity, so the gap A also needs to be changed depending on the part. In the experiment, the power supply side end (first
In the table, the spring constant was measured at two locations: the spring constant (40 kgf/mm) and the load side end (10 kgf/mm), and the gap A was changed for each. In Experiment 1, there was no interaction between the case 1 and the cover 2 at the end on the power supply side, and the case side wall 3 was destroyed due to a short circuit. In Experiment 2, the gap A at the end on the power supply side was set to 0.15 mm, which is about the same molding dimensional accuracy as in the conventional case, and the cover side wall 4 was destroyed. In Experiment 3, the gap A at the end on the power supply side was made 0.5 mm thicker than in Experiment 2, and there was no abnormality even after short circuiting. In Experiment 4, the gap A was made considerably thicker to 0.9 mm at the load-side end where the wall thickness was thinner, but the cover side wall 4 was still destroyed due to short circuit interruption. In Experiment 5, the gap A at the end of the load side was further increased to 1°511.
When setting II11, there was no abnormality even if the short circuit was cut off. As described above, by setting the gap A of the interlocking part 7 to a large appropriate value that exceeds the normal molding dimensional accuracy of 0.3 ribs according to the spring constant of the case side wall 3, the material and wall thickness remain the same as before. It was confirmed that the size and shape can handle short circuit interruption.

【発明の効果】【Effect of the invention】

この発明によれば、掛け合い部におけるケースとカバー
との間の横方向の隙間を０．３ｍｍ以上にすることによ
り、コストアップや材質、形状の変更を伴わずに、短絡
遮断時の外箱の破壊を有効に防止することができる。According to this invention, by making the horizontal gap between the case and the cover at the engagement part 0.3 mm or more, the outer case can be easily removed during a short circuit without increasing costs or changing the material or shape. Destruction can be effectively prevented.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図はこの発明の詳細な説明する外箱の要部横断面図
、第２図は同じく別の形式の外箱の要部横断面図、第３
図はケース側壁のばね定数の測定方法を説明する正面図
、第４図は従来例を説明する外箱の横断面図である。 １・・・ケース、 ２・・・カバー、 ３゜ ４・・・側壁、 ７・・・ 掛け合い部、 Ａ・・・隙間。 １グース 箪 図 笥 図 策 図FIG. 1 is a cross-sectional view of a main part of an outer box for explaining the invention in detail, FIG. 2 is a cross-sectional view of a main part of another type of outer box, and FIG.
The figure is a front view illustrating a method of measuring the spring constant of the side wall of the case, and FIG. 4 is a cross-sectional view of the outer box illustrating a conventional example. 1...Case, 2...Cover, 3゜4...Side wall, 7...Interlocking part, A...Gap. 1 Goose chest of drawers map

Claims (1)

【特許請求の範囲】[Claims] １）モールド樹脂のケースとカバーとからなり、これら
の側壁の合わせ面に互いにいんろう式に嵌まり合う掛け
合い部が設けられた回路遮断器の外箱において、掛け合
い部におけるケースとカバーとの間の横方向の隙間を０
．３ｍｍ以上にしたことを特徴とする回路遮断器の外箱
。1) In the outer case of a circuit breaker, which is composed of a molded resin case and a cover, and has a hooking section that fits into each other in an interlocking manner on the mating surfaces of these side walls, there is a gap between the case and the cover at the hooking section. The horizontal gap of
．． An outer box for a circuit breaker characterized by having a thickness of 3 mm or more.