JP2010010067A - Circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit breaker having high dust preventing performance and capable of obtaining a sufficient quantity of discharge air when arc is generated. <P>SOLUTION: This circuit breaker comprises a case 1 housing a pair of terminal parts; a fixed terminal plate 2 having a fixed contact point 2a; a movable contact 3 having a movable contact point 3a; a cross bar 33, to which the movable contact 3 is fitted to be turned together; and an over-current shut-off means 5 for forcibly separating between the contact points when over-current flows; inside thereof, a discharge plate 6 provided in an opening formed in the case 1 to cover the opening and formed with a discharge hole 6a for discharging gas of the arc, which is generated when the movable contact point 3a separates from the fixed contact point 2a, out of the case 1, and a dust preventing plate 7 to be bent by the gas pressure of the arc to open the discharge hole 6a. The dust preventing plate 7 comprises a fitting part 7b for fitting the dust preventing plate to the case 1 or the discharge plate 6, and a slit 7a is formed between an area facing the discharge hole 6a and the fitting part 7b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a circuit breaker.

Conventionally, as this type of circuit breaker, a pair of terminal portions, a fixed terminal plate having a fixed contact and connected to one terminal portion, and a movable contact contacting and separating from the fixed contact are provided, and the other terminal portion. When an overcurrent flows between the movable contact connected to the device, the crossbar that rotates together with the movable contact, and the fixed contact and the movable contact that are in contact with each other, the crossbar is turned. An overcurrent interrupting means for forcibly separating the movable contact and the fixed contact by being moved is housed in the case, and is covered with an opening formed in the case, and the movable contact is fixed by the overcurrent interrupting means. There is an exhaust plate in which an exhaust hole for discharging an arc gas generated when separating from a contact is formed, and a dustproof plate that closes the exhaust hole of the exhaust plate and opens the exhaust hole only when an arc is generated (For example, refer to Patent Document 1).
Japanese Patent No. 2734615

  In the circuit breaker in the above conventional example, the dustproof plate is bent when an arc is generated to open the exhaust hole and discharge the arc gas to the outside. However, when the dust-proof plate is thin, the dust-proof plate disappears due to the influence of the arc, and when the dust-proof plate is thick, there is a problem that the amount of bending is small and sufficient exhaust cannot be performed.

  The present invention has been made in view of the above reasons, and an object of the present invention is to provide a circuit breaker that is highly dustproof and capable of performing sufficient exhaustion when an arc is generated.

  The invention of claim 1 includes a pair of terminal portions corresponding to input / output, a fixed terminal plate having a fixed contact and connected to one terminal portion of the terminal portion, and a movable contact contacting and separating from the fixed contact An overcurrent flows between the movable contact connected to the other terminal, the crossbar attached to the movable contact, and the fixed contact and the movable contact contacting each other. A case in which an overcurrent interrupting means for forcibly separating the movable contact and the fixed contact by rotating the crossbar is housed in an opening formed in the case, An exhaust plate formed with an exhaust hole for discharging the arc gas generated when the movable contact is separated from the fixed contact by the overcurrent interrupting means to the outside of the case; When generated, the exhaust hole is bent by the gas pressure. In a circuit breaker including an open dustproof plate, the dustproof plate has a mounting portion for mounting on a case or an exhaust plate, and a slit is formed between the region facing the exhaust hole and the mounting portion. It is characterized by.

  According to the present invention, since the exhaust hole is normally closed by the dustproof plate, high dustproofness can be ensured, and when the arc is generated, the dustproof plate is largely bent near the slit so that sufficient exhaust is achieved. It is possible to prevent the gas pressure in the case from increasing and prevent the case from being damaged.

  According to a second aspect of the present invention, in the first aspect of the invention, the dustproof plate is formed in a substantially rectangular shape, and the attachment portion is provided along one of the four sides, and the slit is provided with an attachment portion. It is characterized in that it is formed in a direction approaching the mounting portion from the two opposite sides extending from both ends of the side toward the inside.

  According to this invention, normally, the dustproof plate can hardly be bent because the vicinity of the end portion in the outer direction of the slit is partially overlapped, so that dustproofness can be ensured, and when an arc is generated, by the increase in gas pressure in the case, The overlapping portion of the slits is removed and the dustproof plate is greatly bent, so that a sufficient exhaust amount can be obtained.

  As described above, according to the present invention, there is an effect that it is possible to provide a circuit breaker that is highly dustproof and capable of performing sufficient exhaustion when an arc is generated.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
An embodiment of the present invention will be described with reference to FIGS. In addition, let the direction orthogonal to an up-down left-right direction on the basis of up-down-left-right in FIG.1 (b) be a front-back direction.

  The circuit breaker according to the present embodiment opens and closes three poles with a single opening / closing mechanism. Terminal blocks 10 are formed on both left and right ends of the substantially rectangular parallelepiped case 1, respectively. Three power supply terminal portions 10A are arranged in the front-rear direction, and three load-side terminal portions 10B are arranged in the front-rear direction on the right terminal block 10. Each terminal block 10 is formed with an insulating wall 10a for insulating between adjacent terminal portions (see FIG. 1).

  In the case 1, the left end is connected to the power terminal portion 10 </ b> A and the right end is provided with the fixed contact 2 a, and the right end is connected to the load side terminal portion 10 </ b> B via the lead wire 31. Detects an overcurrent that flows between the contacts at the time of closing, and a movable contact 3 provided with a movable contact 3a at the left end, an open / close mechanism 4 that contacts and separates the fixed contact 2a and the movable contact 3a (between the contacts) And overcurrent interrupting means 5 for forcibly opening the contacts.

  The case 1 is composed of a bottomed box-type body 11 made of a synthetic resin molding and having an open upper surface, and a cover 12 having a lower surface opened on the upper surface of the body 11.

  In the body 11, an insulating wall (not shown) that is divided for each terminal portion is formed so as to insulate adjacent poles.

  Further, an insertion window 12 a through which a handle 30 described later is inserted is formed on the upper surface of the cover 12.

  The fixed contact plate 2 includes a terminal portion 22a having a screw hole 22b formed at the left end, an extending portion 22c extending downward from the right end of the terminal portion 22a, and a right end from the end of the extending portion 22c. A contact piece 22d that extends in the direction and has a fixed contact 2a made of a conductive material having a higher arc resistance than copper such as silver is fixed on the upper surface, for example, made of a conductive material such as copper. .

  The movable contact 3 is formed from a conductive material such as copper in the form of a long plate that is long in the left-right direction, and the left end in the longitudinal direction is made of a conductive material having higher arc resistance than copper such as silver. The movable contact 3a is fixed at a position facing the fixed contact 2a. The right end of the movable contact 3 is electrically connected to a load side terminal portion 10B and a coil (not shown) provided in an electromagnet portion 41 described later by a lead wire 31 formed of a braided wire. At the time of closing, the power terminal portion 10A and the load side terminal portion 10B are electrically connected via the fixed contact plate 2, the movable contact 3, and the lead wire 31. In addition, a rotary shaft 32 is provided substantially at the center of the movable contact 3, and the rotary shaft 32 is pivotally supported by a shaft hole 35 of a cross bar 33 provided straddling the poles. The provided movable contact 3 is attached to the cross bar 33, and can be rotated as the cross bar 33 rotates.

  The cross bar 33 holds the movable contact 3 of each pole at a predetermined interval, and a contact pressure spring 34 formed of a coil spring is provided between the inner surface of the cross bar 33 and the other end of the movable contact 3. Is held in a compressed state. The contact pressure spring 34 is biased by the positional relationship between a point a connected to the cross bar 33, a point b connected to the movable contact 3, and a point c connected to the opening / closing mechanism 4. The direction is determined. For example, when the contact is closed (see FIG. 2 (a)) or opened (see FIG. 2 (d)), the point b is positioned above the straight line connecting the point a and the point c. Therefore, the movable contact 3 is urged counterclockwise by the contact pressure spring 34.

  The opening / closing mechanism 4 is rotatably held by the body 11, connects the operation handle 30 and the cross bar 33, and rotates the cross bar 33 in conjunction with the rotation of the operation handle 30 (FIG. 3). (See (a)).

  The operation handle 30 is provided so as to protrude outside the case 1 through an insertion window 12 a provided in the approximate center of the upper surface of the cover 12. The operation handle 30 is rotatable between an on position that closes the contacts and an off position that opens the contacts. When the operation handle 30 is turned from the off position to the on position, the crossbar 33 is rotated. Turns counterclockwise, the movable contact 3a comes into contact with the fixed contact 2a, and contact pressure is applied between the contacts by the biasing force of the contact pressure spring 34. When the operation handle 30 is turned from the on position to the off position, the cross bar 33 is turned clockwise, and the movable contact 3a is separated from the fixed contact 2a. In addition, since the structure of the opening / closing mechanism 4 as described above is well known, detailed description thereof will be omitted here.

  The overcurrent interruption means 5 includes an electromagnet portion 41, a bimetal 42, a latch member 43, and a link mechanism 9. When an overcurrent flows between the contacts, the crossbar 34 is connected via the link mechanism 9 described later. Is forcibly rotated clockwise to move the movable contact 3a away from the fixed contact 2a.

  The electromagnet portion 41 generates an electromagnetic field due to an overcurrent flowing from the power terminal portion 10A to the coil (not shown) through the fixed contact plate 2, the movable contact 3, and the lead wire 31 when the pole is closed. Is deformed leftward away from the electromagnet portion 41.

  The bimetal 42 is formed in a long flat plate shape that is long in the vertical direction, the lower end is fixed to the electromagnet portion 41 by screwing or the like, and the adjustment screw 42a is inserted and fixed from the right direction to the upper end, and the adjustment screw from the left surface The tip of 42a protrudes. When an overcurrent that is not as large as the short-circuit current flows between the contacts, the heat generated by the temperature rise of the load-side terminal portion 10B or the like is transmitted to the bimetal 42 through the electromagnet portion 41, and the upper end of the bimetal 42 Gradually bends to the left. In addition, when a relatively large overcurrent such as a short circuit current flows between the contacts, the electromagnet portion 41 generates a strong electromagnetic field and instantaneously deflects the upper end of the bimetal 42 to the left. In this way, when an overcurrent occurs, the upper end of the bimetal 42 bends to the left, and the tip of the adjustment screw 42a provided at the upper end presses the latch member 43.

  The latch member 43 is rotatably fixed to the body 11 and is rotated counterclockwise by being pressed against the tip of the adjustment screw 42 a of the bimetal 42 to operate the link mechanism 9.

  The link mechanism 9 is composed of a plurality of link members, and has a function of transmitting force between the latch member 43 and the cross bar 33, and when the latch member 43 rotates counterclockwise. The cross bar 33 is rotated clockwise to forcibly separate the movable contact 3a from the fixed contact 2a (see FIG. 3B). Since the configuration of such overcurrent interrupting means 5 is well known, detailed description thereof will be omitted here.

  Here, in the circuit breaker conventionally used, when an overcurrent such as a short-circuit current flows between the contacts, the electromagnetic repulsive force acting between the fixed contact 2a and the movable contact 3a becomes the contact pressure spring 34. The movable contact 3 is rotated clockwise before the cross bar 33 is rotated clockwise by the overcurrent blocking means 5 and the movable contact 3a is separated from the fixed contact 2a (see FIG. 2 (b)). Then, as the cross bar 33 rotated by the overcurrent interrupting means 5 moves, the movable contact 3 further rotates clockwise, so that it rotates excessively by the amount rotated by the electromagnetic repulsive force. There is a risk of collision with the cover 12 (see FIG. 2C).

  Therefore, in the circuit breaker according to the present embodiment, the substantially triangular adjustment plate 8 is provided inside the lower surface of the body 11, and the intermediate portion of the lead wire 31 is supported on the apex 8 a above the adjustment plate 8. And the tension | tensile_strength of the lead wire 31 connected to the movable contact 3 is adjusted with the said adjustment board 8, and when the movable contact 3 rotates from the closing side to the opening side, by the said tension | tensile_strength , It is limited not to rotate more than the specified value, and collision with the cover 12 is prevented.

  When the movable contact 3a and the fixed contact 2a are separated by the overcurrent interrupting means 5, an arc is generated between the contacts. Therefore, a substantially rectangular opening is arranged in the front-rear direction on the right side surface of the case 1, and an exhaust plate 6 in which an exhaust hole 6a for discharging arc gas is formed in each opening. Further, a dustproof plate 7 is provided on the surface of the exhaust plate 6.

  The exhaust plate 6 is formed in a substantially rectangular flat plate shape, and a plurality of exhaust holes 6 a are formed. From the lower side 16 </ b> A of the exhaust plate 6, two convex portions for fixing the dustproof plate 7 to the opening peripheral edge of the body 11. 6b is formed. Moreover, the recessed part 6c is each formed under the side 16B and 16C each extended from the both ends of 16 A of lower sides.

  The dustproof plate 7 is formed in a substantially rectangular shape by an elastic material having a thickness, the lower side 17A is bent into a U shape, the attachment portion 7b is formed, and the convex portion 6b formed on the exhaust plate 6; The attachment portion 7b is sandwiched and fixed between the opening periphery provided in the case 1. In addition, slits 7a are formed obliquely from the side edges 17B and 17C respectively extending from both ends of the lower side 17A of the dustproof plate 7 in a direction approaching the attachment portion 7b inward (see FIG. 4). . Here, the slit 7a is formed in the middle of the location facing the exhaust hole 6a and the mounting portion 7b. Further, ribs 7c are formed on the side edges 17B and 17C so as to protrude downward from the open end 7d of the slit 7a toward the exhaust plate 6, and the ribs 7c are fitted into the recesses 6c of the exhaust plate 6. The dust-proof plate 7 prevents the dust and the like from entering the case 1 by closing the exhaust hole 6a. When an arc is generated, the dust-proof plate 7 is bent outward by the gas pressure of the arc to open the exhaust hole 6a. , Discharge the arc gas to the outside. Moreover, since the rib 7c is formed in the dustproof plate 7, it is largely bent above the vicinity of the closed end 7e of the slit 7a and hardly deformed below the vicinity of the closed end 7e.

  The dust-proof plate 7 in this embodiment normally ensures dust-proof performance by blocking the exhaust hole 6a without causing bending (see FIG. 5 (a)), and when the arc is generated, the closed end 7e of the slit 7a. It can be greatly bent from the vicinity (see FIG. 5C), and the amount of bending is larger than the deflection of the dust-proof plate 7 ′ without the slit 7a used conventionally (see FIG. 5B), Exhaust can be performed sufficiently, and there is no risk of the case 1 being affected by the arc gas pressure.

  Moreover, since the said slit 7a formed in the dustproof board 7 usually has the location which overlaps with the open end 7d of each slit 7a, it is hard to generate | occur | produce and can secure dustproof property. On the other hand, when the arc is generated, the internal pressure of the case 1 is increased by the gas pressure of the arc, so that the overlapping portion of the slits 7a is detached and greatly bent, and the exhaust can be sufficiently performed.

  Therefore, the circuit breaker in the present embodiment has high dust resistance and can perform sufficient exhaustion when an arc is generated.

(A)-(c) shows the external view of the circuit breaker in embodiment of this invention, (a) is a front view, (b) is a side view, (c) shows a top view. (A)-(d) shows sectional drawing of the principal part of the circuit breaker same as the above, (a) at the time of closing, (b) at the time of electromagnetic repulsion action, (c) at the time of trip , (D) shows the time of opening. (A), (b) shows sectional drawing of the circuit breaker same as the above, (a) is AA sectional drawing at the time of normal operation, (b) is AA sectional view when a breaker trips The figure is shown. The perspective view of the exhaust board and dustproof board in the same as the above is shown. (A)-(c) shows the comparative example of the principal part in the same as the above, (a) is sectional drawing before gas pressure generation, (b) has applied gas pressure when there is no slit in a dust-proof board. (C) shows a cross-sectional view when the gas pressure is applied when the dustproof plate has a slit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Case 2 Fixed terminal board 2a Fixed contact 3 Movable contact 3a Movable contact 5 Overcurrent interruption means 6 Exhaust plate 6a Exhaust hole 7 Dustproof plate 7a Slit 7b Mounting part 10A Power supply terminal part 10B Load side terminal part 33 Crossbar

Claims (2)

A pair of terminal portions corresponding to input / output, a fixed terminal plate having a fixed contact and connected to one terminal portion, and a movable contact contacting and separating from the fixed contact and connected to the other terminal portion When an overcurrent flows between the movable contact, the crossbar that rotates together with the movable contact, and the fixed contact and the movable contact that are in contact with each other, the crossbar is rotated. A case that houses overcurrent blocking means for forcibly separating the movable contact and the fixed contact;
An exhaust plate which covers an opening formed in the case and has an exhaust hole for discharging arc gas generated when the movable contact is separated from the fixed contact by the overcurrent interrupting means to the outside of the case When,
In the circuit breaker provided with a dustproof plate that closes the exhaust hole of the exhaust plate and opens the exhaust hole by bending by the gas pressure at the time of arc gas generation,
The circuit breaker according to claim 1, wherein the dustproof plate includes a mounting portion for mounting to the case or the exhaust plate, and a slit is formed between the region facing the exhaust hole and the mounting portion.   The dust-proof plate is formed in a substantially rectangular shape, and the attachment portion is provided along one of the four sides, and the slit extends from two opposite sides extending from both ends of the side where the attachment portion is provided. 2. The circuit breaker according to claim 1, wherein the circuit breaker is formed in a direction approaching the attachment portion toward the inside.

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