JP2011165514A

JP2011165514A - Circuit breaker

Info

Publication number: JP2011165514A
Application number: JP2010027969A
Authority: JP
Inventors: Atsushi Yoshida; 敦至吉田
Original assignee: Kawamura Electric Inc
Current assignee: Kawamura Electric Inc
Priority date: 2010-02-10
Filing date: 2010-02-10
Publication date: 2011-08-25

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit breaker capable of dispensing with a point contact between a pressure terminal and a terminal seat when a terminal screw is slackened and surely detecting connection failure by making a contact condition quickly result in a non-contact condition. <P>SOLUTION: A connection failure detection circuit is connected to a power supply side terminal 2 connected to an electric wire 4 through the pressure terminal 5, the terminal seat 20 is covered with a terminal cover 10 with an end adjacent to an upper side section of the connected pressure terminal 5, and the pressure terminal 5 is sandwiched by the terminal cover 10 and a controlling plate 11 by preparing the controlling plate 11 adjacent to a lower side section of the pressure terminal 5 on a side face of a housing 1 as a lower part of the terminal seat 20. The connection failure detection circuit determines the connection failure from a potential difference generated between the electric wire 4 and the terminal seat 20 by detecting voltage of terminal seat 20 as well as voltage of the electric wire 4 through a nut 22, and if determining that it is connection failure, the connection failure detection circuit blocks an electric circuit in the same way as abnormal current such as excessive current flows. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

本発明は回路遮断器に関し、特に端子部の接続不良を検出する機能を備えた回路遮断器に関する。 The present invention relates to a circuit breaker, and more particularly to a circuit breaker having a function of detecting a connection failure in a terminal portion.

配電盤や分電盤等の盤内に配設された回路遮断器の多くは、ねじ式の端子を備え、電線に圧着端子を取り付けてねじ締めにより接続している。このようなねじ式の端子は、ねじの緩み等で端子の接続不良が発生する場合があり、接続不良が発生すると接触抵抗が増加して発熱を伴ったり、アーク放電の発生等により端子部が劣化する問題があった。
そのため、このような接続不良を検出する技術が考えられ、例えば本発明者は特許文献１に記載された技術を提案した。これは、電線と端子座との間の電位差を検出し、その値が所定値になったら接続不良と判断するもので、端子部の接続不良を早期に検出することができ、電位差により接続不良を判断するので誤動作の発生がなかった。 Many circuit breakers installed in panels such as switchboards and distribution boards are equipped with screw-type terminals, which are connected by crimping terminals to the electric wires and screwing. Such screw type terminals may cause poor connection of the terminals due to loosening of the screws, etc.If the connection failure occurs, the contact resistance increases and heat is generated, or the terminal part is caused by arc discharge etc. There was a problem of deterioration.
Therefore, a technique for detecting such a connection failure is conceivable. For example, the present inventor has proposed a technique described in Patent Document 1. This is to detect the potential difference between the electric wire and the terminal seat, and judge that the connection is poor when the value reaches a predetermined value. Therefore, no malfunction occurred.

一方、このようなネジ式の端子部を備えた回路遮断器は、接続した電線が作業者のミスにより取り外されないように、端子を封印するための端子カバーが取り付けられるよう設計されている（例えば、特許文献２参照）。 On the other hand, the circuit breaker provided with such a screw-type terminal portion is designed so that a terminal cover for sealing the terminal is attached so that the connected electric wire is not removed due to an operator's mistake ( For example, see Patent Document 2).

特開２００９−２４５８３６号公報JP 2009-245836 A 特開２００５−９３１５７号公報JP 2005-93157 A

しかしながら、上記特許文献１に開示された技術は、圧着端子（電線）と端子座の間の電位差を検出するが、端子ネジが緩んでも圧着端子と端子座が点接触で保持されると、圧着端子と端子座の間の電圧が閾値に至らない状態が発生する。このような場合は、遮断動作しないため、点接触している箇所がジュール熱により上昇することがあった。この発熱は電線の焼損に至ることは無いと考えられるが、このような発熱が発生する前に端子ネジの緩みを検出して電路を遮断するのが望ましい。 However, although the technique disclosed in Patent Document 1 detects a potential difference between a crimp terminal (electric wire) and a terminal seat, if the crimp terminal and the terminal seat are held in point contact even if the terminal screw is loosened, the crimping is performed. A state occurs in which the voltage between the terminal and the terminal seat does not reach the threshold value. In such a case, since the shut-off operation is not performed, the point contact point may rise due to Joule heat. Although it is considered that this heat generation does not lead to burnout of the electric wire, it is desirable to detect the looseness of the terminal screw and interrupt the electric circuit before such heat generation occurs.

そこで、本発明はこのような問題点に鑑み、端子ネジに緩みが発生したら圧着端子と端子座が点接触する状況に至ることが無く、速やかに非接触状態に至ることで確実に接続不良を検出できる回路遮断器を提供することを目的としている。 Therefore, in view of such problems, the present invention does not reach a point contact between the crimp terminal and the terminal seat when the terminal screw is loosened. The object is to provide a circuit breaker that can be detected.

上記課題を解決する為に、請求項１の発明は、ハウジングに固定された端子座と当該端子座に電線を接続するための端子ねじ及びナットとを備えた電源側端子及び負荷側端子を有し、前記電源側端子及び負荷側端子のうち少なくとも一方の端子に前記電線の接続不良を検出する接続不良検出回路が接続され、前記接続不良検出回路は、前記ナットを介して前記電線の電圧を検出すると共に、前記端子座の電圧を検出して、前記電線と前記端子座との間に発生する電位差から接続不良を判断し、接続不良と判断したら過電流等の異常電流が流れた場合と同様に電路を遮断する回路遮断器であって、前記電線は圧着端子を介して前記端子座に接続され、前記接続不良検出回路が接続された端子座は、接続された圧着端子の上側側部に近接或いは当接する端部を有する端子カバーで覆われると共に、前記端子座下部となる前記ハウジングの側面には、前記圧着端子の下側側部に近接或いは当接する規制板が設けられ、前記端子カバーと前記規制板とで圧着端子を挟持し、前記端子座に対する圧着端子の傾倒を防止することを特徴とする。
この構成によれば、電線と端子座との間の電位差を検出して端子部の接続不良を判断することができるので、接続不良を早期に検出することができる。そして、端子ネジの緩みが発生して圧着端子が傾倒して端子座に点接触しようとしても、端子カバーと規制板が圧着端子の傾倒を防止するので、点接触状態となるのを防ぐことができ、接続不良を速やかに検出することができる。更に、圧着端子の傾倒を端子カバーを利用して防ぐので、新たな部材は規制板のみで済み、少ない部材で構成できる。 In order to solve the above problems, the invention of claim 1 includes a power supply side terminal and a load side terminal provided with a terminal seat fixed to the housing and a terminal screw and a nut for connecting an electric wire to the terminal seat. And a connection failure detection circuit for detecting a connection failure of the wire is connected to at least one of the power supply side terminal and the load side terminal, and the connection failure detection circuit detects the voltage of the wire via the nut. And detecting the voltage of the terminal seat, judging a connection failure from a potential difference generated between the wire and the terminal seat, and if an abnormal current such as an overcurrent flows when judged to be a connection failure Similarly, a circuit breaker for interrupting an electric circuit, wherein the electric wire is connected to the terminal seat via a crimp terminal, and the terminal seat to which the connection failure detection circuit is connected is an upper side portion of the connected crimp terminal. Close to or A regulating plate that is covered with a terminal cover having an end portion that is in contact with the lower side portion of the crimp terminal and is provided on a side surface of the housing that is the lower portion of the terminal seat. A crimp terminal is sandwiched between the plates and the tilt of the crimp terminal with respect to the terminal seat is prevented.
According to this configuration, since the potential difference between the electric wire and the terminal seat can be detected to determine the connection failure of the terminal portion, the connection failure can be detected at an early stage. And even if the terminal screw is loosened and the crimping terminal tilts and tries to make point contact with the terminal seat, the terminal cover and the regulation plate prevent the crimping terminal from tilting. Connection failure can be detected quickly. Furthermore, since the tilting of the crimp terminal is prevented by using the terminal cover, the new member is only a restriction plate and can be configured with a small number of members.

請求項２の発明は、請求項１に記載の構成において、前記端子座と前記端子ねじとが直接導通しないように、端子座の前記端子ねじ挿通孔の径を端子ねじの径より大きくする一方、前記ナットが前記端子座と直接導通しないように、前記ナットと前記端子座の間に絶縁部材が介在されてなることを特徴とする。
この構成によれば、端子ねじが緩んだら最初に端子座とナットとの間に電位差を発生させることができるので、この電位差を検出することで端子の接続不良を確実に検出できる。 According to a second aspect of the present invention, in the configuration of the first aspect, the diameter of the terminal screw insertion hole of the terminal seat is made larger than the diameter of the terminal screw so that the terminal seat and the terminal screw do not directly conduct. An insulating member is interposed between the nut and the terminal seat so that the nut does not directly conduct to the terminal seat.
According to this configuration, when the terminal screw is loosened, a potential difference can be first generated between the terminal seat and the nut. Therefore, the connection failure of the terminal can be reliably detected by detecting this potential difference.

請求項３の発明は、請求項１又は２に記載の構成において、前記接続不良検出回路の電線との電気的接続は、接続不良検出回路の回路基板に一端が接続された接触金具の先端を前記ナットに接触させて行い、前記接触金具の先端が前記ナットと前記ハウジングとで挟持された状態で前記ナットに接触することを特徴とする。
この構成によれば、接触金具とナットとの接続は確実になされ、不安定な接触状態となることがない。 According to a third aspect of the present invention, in the configuration according to the first or second aspect, the electrical connection with the electric wire of the connection failure detection circuit is performed by connecting a tip of a contact fitting having one end connected to the circuit board of the connection failure detection circuit. It is carried out by contacting with the nut, and the tip of the contact metal fitting is in contact with the nut while being sandwiched between the nut and the housing.
According to this configuration, the contact metal fitting and the nut are securely connected, and an unstable contact state does not occur.

本発明によれば、電線と端子座との間の電位差を検出して端子部の接続不良を判断することができるので、接続不良を早期に検出することができる。そして、端子ネジの緩みが発生して圧着端子が傾倒して端子座に点接触しようとしても、端子カバーと規制板が圧着端子の傾倒を防止するので、点接触状態となるのを防ぐことができ、接続不良を速やかに検出することができる。更に、圧着端子の傾倒を端子カバーを利用して防ぐので、新たな部材は規制板のみで済み、少ない部材で構成できる。 According to the present invention, since the potential difference between the electric wire and the terminal seat can be detected to determine the connection failure of the terminal portion, the connection failure can be detected at an early stage. And even if the terminal screw is loosened and the crimping terminal tilts and tries to make point contact with the terminal seat, the terminal cover and the regulation plate prevent the crimping terminal from tilting. Connection failure can be detected quickly. Furthermore, since the tilting of the crimp terminal is prevented by using the terminal cover, the new member is only a restriction plate and can be configured with a small number of members.

本発明に係る回路遮断器の一例を示し、（ａ）は電源側端子方向からみた正面図であり、（ｂ）は電源側端子内部を透視した側面説明図である。An example of the circuit breaker which concerns on this invention is shown, (a) is the front view seen from the power supply side terminal direction, (b) is side explanatory drawing which saw through the inside of the power supply side terminal. 電源側端子と接続不良検出回路の関係を示す説明図である。It is explanatory drawing which shows the relationship between a power supply side terminal and a connection failure detection circuit. 図２の構造において、電流の流れを示す説明図であり、（ａ）は正常状態、（ｂ）は接続不良状態を示している。In the structure of FIG. 2, it is explanatory drawing which shows the flow of an electric current, (a) has shown the normal state, (b) has shown the poor connection state.

以下、本発明を具体化した実施の形態を、図面に基づいて詳細に説明する。図１は本発明に係る回路遮断器の一例を示す説明図であり、（ａ）は電源側端子方向からみた正面図であり、（ｂ）は電源側端子内部を透視した側面説明図である。この図１において、１は回路遮断器のハウジング、２は電源側端子、３は電路をオン／オフ操作する操作ハンドル、４は電源側電路を構成する電線、５は電線４の端部に取り付けられた圧着端子、６は電路の開閉部を構成する一方の接触子（固定接触子）、７は開閉部を構成する他方の接触子（可動接触子）、８は端子の接続不良を検出する接続不良検出回路を形成した回路基板、１０は端子カバー、１１は規制板である。
尚、可動接触子７は、図示しない過電流検出部、短絡電流検出部を介して図示しない負荷側端子に接続されている。 DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described in detail with reference to the drawings. 1A and 1B are explanatory views showing an example of a circuit breaker according to the present invention, wherein FIG. 1A is a front view seen from the direction of a power supply side terminal, and FIG. . 1, 1 is a circuit breaker housing, 2 is a power supply side terminal, 3 is an operation handle for turning on / off the electric circuit, 4 is an electric wire constituting the power supply side electric circuit, and 5 is attached to an end of the electric wire 4 6 is one contact (fixed contact) constituting the open / close portion of the electric circuit, 7 is the other contact (movable contact) constituting the open / close portion, and 8 detects a connection failure of the terminal. A circuit board on which a connection failure detection circuit is formed, 10 is a terminal cover, and 11 is a regulating plate.
The movable contact 7 is connected to a load-side terminal (not shown) via an overcurrent detector (not shown) and a short-circuit current detector (not shown).

電源側端子２は、端子座２０、端子ねじ２１、ナット２２等で構成され、端子座２０は固定接触子６を一体に形成した端子金具２３の一部として形成されている。この端子金具２３は、固定ねじ２４によりハウジング１の所定の端子金具取付部２５に固定される。 The power supply side terminal 2 includes a terminal seat 20, a terminal screw 21, a nut 22, and the like. The terminal seat 20 is formed as a part of a terminal fitting 23 in which the fixed contact 6 is integrally formed. The terminal fitting 23 is fixed to a predetermined terminal fitting mounting portion 25 of the housing 1 by a fixing screw 24.

端子カバー１０はＬ字状に成形された樹脂板であり、端子ネジ２１上方を覆う天面１０ａと端子部の電線挿入口上部を覆う前面１０ｂとを有している。天面１０ａには取り外しできないようにワイヤ等で封止するための環状突起１０ｃが設けられている。そして、前面１０ｂの端子前方部位１０ｄは、端子ネジ２１の側部まで垂下した高さを有し、接続した電線４の圧着端子５の環状首部５ａに近接或いは当接するよう構成されている。 The terminal cover 10 is a resin plate molded in an L shape, and has a top surface 10a that covers the upper portion of the terminal screw 21 and a front surface 10b that covers the upper part of the wire insertion port of the terminal portion. The top surface 10a is provided with an annular protrusion 10c for sealing with a wire or the like so that it cannot be removed. The front terminal portion 10d of the front surface 10b has a height depending on the side of the terminal screw 21 and is configured to approach or abut on the annular neck portion 5a of the crimp terminal 5 of the connected electric wire 4.

一方、規制板１１は長方形の樹脂製板体であり、ハウジング１の前面の端子部下に貼着され、規制板１１の上辺が端子座２０の上面と同一の高さとなるよう取り付けられている。この結果、接続された圧着端子５は、端子カバー１０と規制板１１とで把持される状態となり回転し難くい。
具体的に、圧着端子５は電線４に取り付けられる際、環状の首部が圧着操作されることで首部５ａは横に広がり楕円に変形する。そのため、ハウジング１の縦方向に対して横方向の径が大きくなり、端子カバー１０と規制板１１により上下方向から挟持された圧着端子５の上下方向に僅かな隙間があったとしても、首部５ａの横方向の径が大きいため、回転が規制される。その結果、端子ネジ２１が緩んでも点接触し難い。 On the other hand, the restriction plate 11 is a rectangular resin plate, and is attached to the front surface of the housing 1 under the terminal portion so that the upper side of the restriction plate 11 is flush with the upper surface of the terminal seat 20. As a result, the connected crimp terminal 5 is in a state of being gripped by the terminal cover 10 and the restriction plate 11 and is difficult to rotate.
Specifically, when the crimp terminal 5 is attached to the electric wire 4, the neck part 5 a spreads laterally and deforms into an ellipse when the annular neck part is crimped. Therefore, even if there is a slight gap in the vertical direction of the crimp terminal 5 sandwiched from the vertical direction by the terminal cover 10 and the restriction plate 11 even if the diameter in the horizontal direction is larger than the vertical direction of the housing 1, the neck portion 5a. Since the diameter in the horizontal direction is large, rotation is restricted. As a result, even if the terminal screw 21 is loose, it is difficult to make point contact.

尚、図１では端子カバー前面１０ｂの端子間に対応する部位１０ｅも端子部前方部位１０ｄとほぼ同じ高さで形成されているが、電線挿入位置より更に下方まで伸ばしても良い。また、規制板１１はハウジング１に一体形成しても良いし、ネジ止めにより取り付けても良い。 In FIG. 1, the portion 10e corresponding to the terminals on the front surface 10b of the terminal cover is also formed at almost the same height as the terminal portion front portion 10d. Further, the regulation plate 11 may be formed integrally with the housing 1 or may be attached by screwing.

図２は、電源側端子２と接続不良検出回路Ａの関係を示す説明図である。この図２に示すように、端子金具２３の一端には端子座２０が形成され、他端には固定接点６ａを備えた固定接触子６が形成されている。そして、この端子金具２３とナット２２とが接続不良検出回路Ａに接続されている。
端子金具２３の略中央には、端子金具２３をハウジング１に固定するためのねじ孔２３ａが設けられている。端子ねじ２１を挿通するために端子座２０に形成された挿通孔２０ａは、端子ねじ２１の径より大きな径で形成され、挿通した端子ねじ２１が端子座２０に接触しても電気的な接続が発生しないよう構成されている。 FIG. 2 is an explanatory diagram showing the relationship between the power supply side terminal 2 and the connection failure detection circuit A. As shown in FIG. As shown in FIG. 2, a terminal seat 20 is formed at one end of the terminal fitting 23, and a fixed contact 6 having a fixed contact 6a is formed at the other end. The terminal fitting 23 and the nut 22 are connected to the connection failure detection circuit A.
A screw hole 23 a for fixing the terminal fitting 23 to the housing 1 is provided in the approximate center of the terminal fitting 23. The insertion hole 20 a formed in the terminal seat 20 for inserting the terminal screw 21 is formed with a diameter larger than the diameter of the terminal screw 21, and electrical connection is made even if the inserted terminal screw 21 contacts the terminal seat 20. Is configured not to occur.

一方、ナット２２の端子座２０との接触面には、絶縁部材からなる絶縁リング２７が貼着され、端子ねじ２１により両者を密着させた状態でも、ナット２２と端子座２０が直接電気的に接続されないように構成されている。尚、端子ねじ２１は、通常のねじにワッシャ等を取り付けた構成のものが使用される。 On the other hand, an insulating ring 27 made of an insulating member is affixed to the contact surface of the nut 22 with the terminal seat 20, and the nut 22 and the terminal seat 20 are directly and electrically connected even when they are brought into close contact with the terminal screw 21. It is configured not to be connected. In addition, the terminal screw 21 has a configuration in which a washer or the like is attached to a normal screw.

回路基板８は、固定接触子６の下部となるハウジング１の内底部に配置され、端子金具２３と合わせて固定ねじ２４によりハウジング１に固定されている。この固定ねじ２４は、ハウジング１の下方から、回路基板８、ハウジング１の端子金具取付部２５を介して端子金具２３のねじ孔２３ａに螺入され、回路基板８及び端子金具２３が同時に固定される。即ち、端子座２０及び固定接触子６は、回路基板８と共に固定ねじ２４によりハウジング１に固定される。この結果、回路基板８の図示しない所定の回路パターンと端子座２０とは電気的に導通状態となる。 The circuit board 8 is disposed on the inner bottom portion of the housing 1, which is a lower portion of the fixed contact 6, and is fixed to the housing 1 by a fixing screw 24 together with the terminal fitting 23. The fixing screw 24 is screwed into the screw hole 23a of the terminal fitting 23 from below the housing 1 via the circuit board 8 and the terminal fitting mounting portion 25 of the housing 1, so that the circuit board 8 and the terminal fitting 23 are fixed simultaneously. The That is, the terminal seat 20 and the stationary contact 6 are fixed to the housing 1 together with the circuit board 8 by the fixing screw 24. As a result, a predetermined circuit pattern (not shown) of the circuit board 8 and the terminal seat 20 are electrically connected.

また、回路基板８の電源側端子２側の端部には、電源側端子２のナット２２に電気的接続を図るための接触金具２９が連結されている。接触金具２９は、帯状金属板を折り曲げて形成され、基部に回路基板８の端部を挟持するコ持状連結部２９ａを有し、折り曲げられた先端部が、回路基板８の底面に半田付けされ、回路基板８に形成されている回路パターンに連結されている。そして、接触金具２９の先端部は、ハウジング１のナット２２を収容する収容面３０とナット２２の間に配置され、両者に挟持されてナット２２に密着して電気的接続が成されている。 Further, a contact fitting 29 for electrical connection to the nut 22 of the power supply side terminal 2 is connected to the end of the circuit board 8 on the power supply side terminal 2 side. The contact metal fitting 29 is formed by bending a band-shaped metal plate, and has a hook-like connecting portion 29 a that holds the end of the circuit board 8 at the base, and the bent tip is soldered to the bottom surface of the circuit board 8. And connected to the circuit pattern formed on the circuit board 8. And the front-end | tip part of the contact metal fitting 29 is arrange | positioned between the accommodation surface 30 which accommodates the nut 22 of the housing 1, and the nut 22, and is pinched | interposed into both and is closely_contact | adhered to the nut 22 and the electrical connection is made.

一方、接続不良検出回路Ａは、ナット２２と端子金具２３を抵抗体３２を介して接続した図示しない電位差検出回路を有し、この抵抗体３２に印加された電圧を受けて接続不良を検出し、検出信号を出力するよう構成されている。この接続不良検出の原理は以下のようである。
端子ねじ２１は圧着端子５側となる上方から挿入され、端子金具２３に挿入された後、ナット２２に螺入されて圧着端子５と端子金具２３とは密着して連結される。この状態において、電流は圧着端子５と端子金具２３の間で良好に流れる。 On the other hand, the connection failure detection circuit A has a potential difference detection circuit (not shown) in which the nut 22 and the terminal fitting 23 are connected via a resistor 32, and detects a connection failure by receiving a voltage applied to the resistor 32. The detection signal is output. The principle of this connection failure detection is as follows.
The terminal screw 21 is inserted from the upper side on the crimp terminal 5 side, inserted into the terminal fitting 23, and then screwed into the nut 22 so that the crimp terminal 5 and the terminal fitting 23 are in close contact with each other. In this state, current flows favorably between the crimp terminal 5 and the terminal fitting 23.

図３は、この接続された端子部の電路電流の流れを矢印で示した説明図であり、図３（ａ）は、良好な接続状態、図３（ｂ）は端子ねじ２１に緩みが発生して接続不良が発生した状態の流れを示している。図３に示すように、圧着端子５と端子金具２３（端子座２０）が密着した状態では、圧着端子５から端子金具２３に矢印Ｌ１に示すように電路電流が良好に流れるため、ナット２２と端子金具２３の間に電位差は発生しない。従って、接続不良検出回路Ａは検出信号を出力しない。 FIGS. 3A and 3B are explanatory diagrams showing the flow of the circuit current of the connected terminal portions with arrows. FIG. 3A shows a good connection state, and FIG. 3B shows that the terminal screw 21 is loose. Thus, the flow of a state where a connection failure has occurred is shown. As shown in FIG. 3, in the state where the crimp terminal 5 and the terminal fitting 23 (terminal seat 20) are in close contact with each other, since the electric circuit current flows favorably from the crimp terminal 5 to the terminal fitting 23 as shown by the arrow L1, There is no potential difference between the terminal fittings 23. Therefore, the connection failure detection circuit A does not output a detection signal.

ところが、端子ねじ２１の緩み等で圧着端子５と端子金具２３との密着状態が不安定になると、圧着端子５から端子金具２３に直接電路電流が流れない場合が発生する。このような場合、アーク放電が発生するようになり、図３（ｂ）に示すようにナット２２及び接続不良検出回路Ａの抵抗体３２を介して矢印Ｌ２に示すように負荷電流が流れようとする。その結果、抵抗体３２に電圧降下が発生し、接続不良検出回路Ａが検出信号を出力する。
こうして接続不良検出回路Ａが接続不良を検出すると、過電流を検知した場合等と同様に図示しない遮断機構部が遮断動作し、可動接触子７が固定接触子６から解離して電路が遮断される。 However, when the contact state between the crimp terminal 5 and the terminal fitting 23 becomes unstable due to loosening of the terminal screw 21 or the like, there is a case where the electric circuit current does not flow directly from the crimp terminal 5 to the terminal fitting 23. In such a case, arc discharge occurs, and a load current flows as shown by an arrow L2 through the nut 22 and the resistor 32 of the connection failure detection circuit A as shown in FIG. To do. As a result, a voltage drop occurs in the resistor 32, and the connection failure detection circuit A outputs a detection signal.
When the connection failure detection circuit A detects a connection failure in this way, the unillustrated blocking mechanism portion performs a blocking operation as in the case of detecting an overcurrent, and the movable contact 7 is dissociated from the fixed contact 6 and the electric circuit is blocked. The

このように、電線４と端子座２０との間の電位差を検出して端子部の接続不良を判断することができるので、接続不良を早期に検出することができる。そして、端子ネジ２１の緩みが発生して圧着端子５が傾倒して端子座２０に点接触しようとしても、端子カバー１０と規制板１１が圧着端子５の傾倒を防止するので、点接触状態となるのを防ぐことができ、接続不良を速やかに検出することができる。更に、圧着端子５の傾倒を端子カバー１０を利用して防ぐので、新たな部材は規制板１１のみで済み、少ない部材で構成できる。
また、端子座２０の端子ねじ挿通孔２０ａの径を端子ねじ２１の径より大きくし、ナット２２と端子座２０の間に絶縁部材２７が介在されるので、端子ねじ２１が緩んだら、最初に端子座２０とナット２２との間に電位差を発生させることができ、この電位差を検出することで端子の接続不良を確実に検出できる。
更に、接触金具２９はナット２２とハウジング１とで挟持されるので、接触金具２９とナット２２との接続は確実になされ、不安定な接触状態となることがない。 Thus, since the potential difference between the electric wire 4 and the terminal seat 20 can be detected to determine the connection failure of the terminal portion, the connection failure can be detected at an early stage. Even if the terminal screw 21 is loosened and the crimping terminal 5 is tilted to make point contact with the terminal seat 20, the terminal cover 10 and the regulation plate 11 prevent the crimping terminal 5 from tilting. Can be prevented, and a connection failure can be detected promptly. Further, since the tilting of the crimp terminal 5 is prevented by using the terminal cover 10, the new member is only the restriction plate 11 and can be configured with a small number of members.
Moreover, since the diameter of the terminal screw insertion hole 20a of the terminal seat 20 is made larger than the diameter of the terminal screw 21 and the insulating member 27 is interposed between the nut 22 and the terminal seat 20, if the terminal screw 21 is loosened, first, A potential difference can be generated between the terminal seat 20 and the nut 22, and by detecting this potential difference, it is possible to reliably detect a terminal connection failure.
Furthermore, since the contact metal fitting 29 is clamped between the nut 22 and the housing 1, the contact metal fitting 29 and the nut 22 are securely connected, and an unstable contact state does not occur.

尚、上記実施形態では、電源側端子２に接続不良検出回路Ａを接続し、端子カバー１０及び規制板１１を取り付けているが、負荷側端子に接続不良検出回路Ａを接続した場合は、端子カバー１０及び規制板１１も負荷側端子側に取り付けることになる。 In the above embodiment, the connection failure detection circuit A is connected to the power supply side terminal 2 and the terminal cover 10 and the regulation plate 11 are attached. However, when the connection failure detection circuit A is connected to the load side terminal, the terminal The cover 10 and the regulation plate 11 are also attached to the load side terminal side.

１・・ハウジング、２・・電源側端子、４・・電線、５・・圧着端子、６・・固定接触子、８・・回路基板、１０・・端子カバー、１１・・規制板、２０・・端子座、２０ａ・・挿通孔、２１・・端子ねじ、２２・・ナット、２３・・端子金具、２３ａ・・ねじ孔、２４・・固定ねじ、２７・・絶縁リング（絶縁部材）、２９・・接触金具、３２・・抵抗素子、Ａ・・接続不良検出回路。 1 .. Housing 2 .. Power supply side terminal 4.. Electric wire 5 .. Crimp terminal 6 .. Fixed contactor 8 .. Circuit board 10 .. Terminal cover 11. · Terminal seat, 20a · · Insertion hole, 21 · · Terminal screw, 22 · · Nut, 23 · · Terminal fitting, 23a · · Screw hole, 24 · · Fixing screw, 27 · · Insulating ring (insulating member), 29 ..Contact metal fittings, 32..Resistance element, A..Connection failure detection circuit.

Claims

A power supply side terminal and a load side terminal provided with a terminal seat fixed to the housing and a terminal screw and a nut for connecting an electric wire to the terminal seat; at least one of the power supply side terminal and the load side terminal A connection failure detection circuit that detects a connection failure of the wire is connected to the terminal, the connection failure detection circuit detects the voltage of the wire through the nut and detects the voltage of the terminal seat, A circuit breaker that cuts off the electric circuit in the same manner as when an abnormal current such as an overcurrent flows when a poor connection is judged from the potential difference generated between the electric wire and the terminal seat,
The electric wire is connected to the terminal seat through a crimp terminal, and the terminal seat to which the connection failure detection circuit is connected is covered with a terminal cover having an end portion that is close to or abuts on the upper side portion of the connected crimp terminal. In addition, a side plate of the housing, which is the lower part of the terminal seat, is provided with a regulation plate that is close to or in contact with the lower side portion of the crimp terminal, and sandwiches the crimp terminal between the terminal cover and the regulation plate, A circuit breaker characterized by preventing the crimp terminal from tilting with respect to the terminal seat.

The diameter of the terminal screw insertion hole of the terminal seat is made larger than the diameter of the terminal screw so that the terminal seat and the terminal screw are not directly connected, while the nut is not directly connected to the terminal seat. 2. The circuit breaker according to claim 1, wherein an insulating member is interposed between the terminal base and the terminal seat.

The electrical connection with the wire of the connection failure detection circuit is performed by contacting the nut with the tip of a contact fitting whose one end is connected to the circuit board of the connection failure detection circuit,
3. The circuit breaker according to claim 1, wherein a tip of the contact fitting contacts the nut while being sandwiched between the nut and the housing.