JP5327038B2 - Circuit breaker - Google Patents

Abstract

A circuit breaker that includes an overcurrent release device, adapted for automatic assembly, with a thermal electromagnetic trip unit is provided which prevents a metallic melt produced by a short circuit interruption from adhering to an opening and closing mechanism or the overcurrent release device. The circuit breaker comprises a middle housing (2), a lower housing and an upper housing; the middle housing (2) accommodates an opening and closing mechanism (51), and an overcurrent release device (52) that detects an overcurrent, to cause the opening and closing mechanism (51) to move pivotally; the lower housing (3) accommodates a circuit interrupting mechanism including an arc extinguisher that interrupts an arc generated between a movable contact arm (13) provided to a crossbar (12) that moves pivotally in an interlocking relation with the opening and closing mechanism (51) and a stationary contact arm (9) that repeats making contact with and moving apart from the movable contact arm (13); and the upper housing covers the middle housing (2), the lower housing and components accommodated within the middle housing (2); wherein the circuit interrupting mechanism (51) is covered by the middle housing (2), and the overcurrent release device (52) is accommodated in the middle housing (2) by press-fitting the release device (52).

Description

  The present invention relates to a circuit breaker such as a circuit breaker for wiring or an earth leakage breaker, and more particularly to a configuration in which an overcurrent tripping device and the like are arranged so as to be suitable for automatic assembly.

  The circuit breaker has a function to open and close the electric circuit by operating the operation handle provided in this circuit breaker, that is, not only the switch function, but also prevent the electric wire and load equipment from being burned out due to overcurrent flow. In order to do so, it plays a big role of cutting off the electric circuit. In detecting this overcurrent, it is well known that the overcurrent is classified into a thermal type, an electromagnetic type, and an electronic type. Of these, the electronic type is installed in the circuit breaker. The signal obtained by the current transformer is processed by an internal CPU. Therefore, by adding a setting signal from the outside to the CPU, the rated current of the electronic circuit breaker can be easily changed, and particularly in obtaining cooperation with a load device (for example, a starting current of an electric motor). It is also well known that it is powerful. The overcurrent tripping device in this case is generally a so-called unit, and therefore has an advantage that automatic assembly of the circuit breaker can be obtained relatively easily (for example, a patent Reference 1).

  On the other hand, this electronic type requires the current transformer described above and an electronic circuit such as a CPU, so the price rise is unavoidable, and in particular, AF (abbreviation of ampere frame, its circuit breaker can be energized. For products with a small maximum value (specifically 63AF / 125AF, etc.), the price difference between thermal and thermodynamic electromagnetic is very large. This is one of the reasons why is widely used. Note that the overcurrent tripping device in this case is firmly fixed to the electric circuit, that is, the casing constituting the circuit breaker, in consideration of the bending of the bimetal due to heat or the movement of the movable iron core due to electromagnetic force. It is desirable to keep it (for example, refer to Patent Document 2).

  By the way, the “overcurrent detection” described so far refers to a relatively small current (of course, large for the rated current) because of the detection, but it goes without saying that the overcurrent is a large current such as a short-circuit current. Such overcurrent interruption, that is, short circuit interruption is also performed by a circuit breaker. This short circuit interruption is not limited to the fact that each company has surpassed how much it has a large interruption capacity with an increase in power supply capacity, especially in circuit breakers used for home use etc. Because of the small size of the outer shape, it is important to improve the breaking ability how to reduce the short-circuit current, that is, how to increase the current limiting action. One means for enhancing the current limiting action is to increase the opening speed by directly transmitting the movement of the movable core due to the electromagnetic force generated when the short-circuit current is applied to the movable contact. In addition, a so-called arc travel interruption method that quickly guides an arc generated between both contacts to an arc extinguishing device is also widely known (see, for example, Patent Document 3).

JP-A-9-270225 (page 3, right column, line 26 to page 4, left column, line 4, FIG. 3 and FIG. 8) JP 2006-236798 A (page 4, lines 18 to 24, FIGS. 1 and 2) Japanese Utility Model Publication No. 56-135649 (page 12, line 19 to page 11, line 11, FIGS. 5 to 7)

  In the circuit breaker disclosed in Patent Document 3, the so-called partition between the arc extinguishing device and the operation mechanism is only the upper arc traveling plate (on the sheet of FIG. 3), and its airtightness is not so high. However, there is a problem that the metal melt generated due to the short-circuit interruption adheres to the opening / closing mechanism and the like, and the insulation lowers due to the wraparound of the arc gas. On the other hand, the short-circuit sensor and the bimetal device are provided on the support frame that forms the operation mechanism, so that the characteristics can be stabilized, but automatic assembly is not intended in the first place, and this causes the cost reduction. Obviously it can be done. In addition, it is expected to be difficult to cope with poor adjustment and misassembly.

  When considering only the airtightness at the time of short circuit interruption, one of the solutions is shown in the circuit breaker of Patent Document 2. However, in this case, since the overcurrent tripping device requires the middle cover to be shielded from the arc extinguishing device, it must inevitably be fixed to the lower case by screwing, which is also difficult for automatic assembly. There is. That being said, as described above, it is difficult to say that relying on the overcurrent tripping device electronically only for automatic assembly is practical.

  The present invention has been made to solve the above-described problems, and is a thermal electromagnetic overcurrent tripping device, but is also suitable for automatic assembly, and has a metal melting generated when a short circuit is interrupted. An object of the present invention is to obtain a circuit breaker that prevents adhesion of an object to an opening / closing mechanism part or the overcurrent tripping device.

  The circuit breaker according to the present invention accommodates an opening / closing mechanism portion having an operation handle and disposed between mutually opposed frame plates, and an overcurrent tripping device for detecting the overcurrent and rotating the opening / closing mechanism portion. An arc cutter that cuts off an arc generated between the movable middle base, a movable contact provided on a crossbar that rotates in conjunction with the opening / closing mechanism, and a stationary contact that repeatedly contacts and separates from the movable contact. And a cover that covers the middle base, the base, and each component housed in the middle base, wherein the middle part is covered with the middle base. The overcurrent tripping device is housed in the base by fixing by press-fitting.

  As described above, the present invention can provide a circuit breaker having a high breaking capacity with reduced manufacturing costs.

It is an external appearance perspective view of the circuit breaker which shows Embodiment 1 of this invention. It is the figure which showed accommodation of the member to the middle base in FIG. It is the figure which showed the overcurrent tripping apparatus in FIG. FIG. 2 is a plan view and a cross-sectional view showing a middle base in FIG. 1. FIG. 2 is a plan view and a cross-sectional view showing a base in FIG. 1. It is sectional drawing at the time of making the middle base fit to the base in FIG. It is the figure which showed the interruption | blocking part in FIG.

Embodiment 1 FIG.
FIG. 1 is a perspective view of a circuit breaker in a trip state according to Embodiment 1 of the present invention. FIG. 1A is an external view, and FIG. 1B is an exploded view of a cover, a middle base, and a base from FIG. Is shown. FIG. 2 is a diagram showing housing of the member in the middle base in FIG. 1B, and FIG. 3 is a diagram showing an overcurrent tripping device and a yoke for one pole from FIG. 4 and 5 show a middle base and a base, respectively, (a) is a plan view corresponding to the X view in FIG. 1 (b), (b) is a sectional view, and FIG. 6 is a middle base. 6 is a cross-sectional view (corresponding to (b) of FIG. 4 and FIG. 5) when the are fitted. FIG. 7 is a view showing housing of the member in the base in FIG.

  In FIG. 1, the insulating casing of the circuit breaker 101 for three poles includes a cover 1, a middle base 2, and a base 3, and of these, the middle base 2 includes an opening / closing mechanism 51 that includes an operation handle 4. The overcurrent tripping devices 52 corresponding to the number of poles (in this case, three) are stored in the base 3, and the arc extinguishing devices 53 corresponding to the number of poles are accommodated in the base 3, respectively. Among these, for the middle base 2, the side plates 2 a and 2 a of the middle base 2 are fitted into the recesses 3 a and 3 a of the base 3 in order to prevent damage due to an internal pressure increase due to an arc generated at the time of interruption. Therefore, the side plates 2a and 2a form a part of the insulating housing. The operation handle 4 protrudes from the handle window hole 1a of the cover 1 so that the operation handle 4 can be operated in the ON direction (on the paper in FIG. 1, clockwise) or the OFF direction (on the paper in FIG. 1, counterclockwise). From the positional relationship between the arc-extinguishing device 53 and the arc-extinguishing device 53, it is well known that 5 is a power supply side terminal and 6 is a load side terminal.

  FIG. 2 shows a yoke 7 which is a member constituting the overcurrent tripping device 52, which is a main part of the present invention, but other than that, that is, the overcurrent tripping device 52 excluding the yoke 7 is shown. The opening / closing mechanism 51 and the arc extinguishing device 53 (see FIG. 1B) are also well known. That is, a fixed contact 9 having a fixed contact 8 at one end and fixed to the yoke 7 is connected to the power supply side terminal 5 through a flexible copper wire 10 and has a movable contact 11 at one end. Contact and separation are repeated between the movable contact 13 held by the cross bar 12 that rotates in conjunction with the portion 51, and the contact between the fixed contact 8 and the movable contact 11 is particularly caused by the separation. The arc generated between them is cut by the arc extinguishing device 53.

  The opening / closing mechanism 51 includes a handle arm 15 pivotally supported on a frame 14 formed by a pair of opposed frame plates 14A and 14B, an operation handle 4 fixed to the handle arm 15, and a frame. 14, which is pivotally supported by a pivot 14, and which is rotated by an operation of an overcurrent tripping device 52, which will be described later, and a latch 17. Similarly, a so-called unit is formed by a crossbar 12 pivotally supported by the frame 14. The frame plate 14A (14B) has foot portions 14A1 and 14A2 on the front and rear sides in the power source / load direction, and these foot portions 14A1 and 14A2 are provided in the insertion holes 2b (FIG. The opening / closing mechanism 51 is fixed to a predetermined position in the insulating housing. Here, details of the toggle link mechanism, that is, manual operation (on to off, off to on) of the circuit breaker 101, trip operation, or reset operation after trip are not essential parts of the present invention. The above detailed explanation is omitted (for the explanation of each operation, see Japanese Patent Application No. 2008-317552, which is a prior application by the same inventor).

  As shown in FIG. 3, the overcurrent tripping device 52 is electrically connected to the fixed contact 9 having a fixed contact 8 at one end when viewed in the current path (hereinafter simply referred to as connection). Connected to the coil 18, the relay terminal 19 connected to the coil 18, the bimetal 20 connected to the relay terminal 19, and an arbitrary location for obtaining a desired bending amount due to the heat generation of the bimetal 20. The flexible copper stranded wire 21 (see also FIG. 2) and the load-side terminal 6 connected to the flexible copper stranded wire 21 are used. 9, the fixed iron core 22 fixed together with the yoke 7, the insulating pipe 23 covering the fixed iron core 22 and positioned at the inner diameter of the coil 18, and positioned at the inner diameter of the insulating pipe 23 and moving against a biasing spring (not shown). It is constituted by a movable core 24 that. In other words, the overcurrent tripping device 52 is a thermodynamic electromagnetic type, and the thermal portion is connected to the yoke 7, the coil 18, the fixed iron core 22, the insulation by the relay terminal 19, the bimetal 20, and the flexible copper strand 21. The electromagnetic parts are formed by the pipe 23, the urging spring, and the movable iron core 24, respectively.

  The operation of the overcurrent tripping device 52 is well known as described above. That is, when the overload current flows for a predetermined time or more, the bimetal 20 is bent in the right direction on the paper surface, so that the adjusting screw portion 20a. Rotates the trip bar 16, and the latch 17 in contact with the trip bar 16 is rotated by this rotation, so that the opening / closing mechanism 51 is tripped and the movable contact 13 is separated from the fixed contact 9. To do. On the other hand, when a short-circuit current flows, a large magnetic force is generated in the coil 18, and the movable iron core 24 moves rightward against the spring force of the biasing spring, thereby rotating the latch 17 directly. Similarly, the opening / closing mechanism 51 is tripped. The overcurrent tripping device 52 is housed in the insulating housing by inserting the load side terminal 6 into the base 3 and the yoke 7 and the relay terminal 19 into the middle base 2, respectively. Of these, the insertion of the yoke 7 into the middle base 2 is the main part of the present invention, and will be described in detail below.

  In addition to the relay terminal 19 and the load side terminal 6 described above, the power source side terminal 5 has the insertion hole 2c (relay terminal 19) and insertion groove 3b (shown in FIG. 4 and FIG. Only the insertion into the load side terminal 6) and the insertion groove 3c (the power source side terminal 5) does not require the two terminals 5 and 6 to be firmly fixed. On the other hand, with respect to the yoke 7, in view of the point that there is a movable part called a movable iron core 24 and the point that there is a bimetal 20 that is mechanically connected (via a fixed contact 9, a coil 18, and a relay terminal 19). Since the movement (curvature) of the movable iron core 24 and the bimetal 20 affects the current characteristics of the circuit breaker 101, the fixing due to the insertion must be strong.

  Therefore, in the present invention, the yoke 7 is provided with two bent portions 7a, and the middle base 2 is provided with a second hole 2e into which the bent portion 7a is fitted. The dimensional relationship between the bent portion 7a and the second hole 2e will be described in detail. The inner dimension B between the partitions of the middle base 2 at the portion where the yoke 7 is inserted is slightly smaller than the both end size A including the bent portion 7a. (A> B). On the other hand, the inter-partition wall inner dimension C of the second hole 2e is made the same as A (A = C), and the area of the inner dimension C is matched with the surface area D of the bent portion 7a. In this way, when the yoke 7 is inserted, the partition wall made of thermoplastic resin opens slightly outward, and when the bent portion 7a reaches the inner dimension C, the partition wall opened outward returns to its original shape and is bent. The movement of the part 7a is prevented. That is, once the overcurrent tripping device 52 is inserted, it is difficult to pull it out, coupled with the fact that the overcurrent tripping device 52 is fixed to at least one of the poles. This means that it is firmly fixed at the position, and thus contributes to stabilization of current characteristics.

  In this way, it is not necessary to fix the overcurrent tripping device 52 to the insulating housing by, for example, screw tightening or the like, and as is clear from FIGS. Since the circuit breaker 101 is formed by so-called lamination, automatic assembly is possible, and the manufacturing cost can be suppressed. The second hole 2e literally penetrates as a “hole” in the mold production of the middle base 2, but is not necessarily limited to this form. If the yoke 7 does not float, “ The “hole” may be closed.

  However, in view of the manufacturing cost of the mold, it is preferable to penetrate the mold as a “hole”. Incidentally, an arc extinguishing device 53 is placed under the middle base 2 where the overcurrent tripping device 52 is fixed, as shown in FIG. On the other hand, although the 2nd hole 2e is obstructed to some extent by the bending part 7a, it is not perfect. Therefore, it is expected that the arc gas generated in the arc extinguishing device 53 at the time of short circuit interruption will reach the opening / closing mechanism 51 through the second hole 2e, which is not preferable. Therefore, in the first embodiment, the protrusion 3e is provided in the power source-load direction of the base 3 including the position of the second hole 2e (see FIG. 5B). Thereby, as is apparent from FIG. 6, when the middle base 2 is fitted to the base 3, the second hole 2e is completely closed by the protrusion 3e, and thus the blocking performance is particularly improved. be able to. Moreover, the protrusion 3e is provided in advance to ensure insulation between the poles, particularly a creepage distance. However, the automatic assembly described above, stabilization of characteristics, and improvement of the shut-off performance are also provided. There is no increase in cost such as the addition of parts in realizing the above.

  Now, with respect to the improvement of the interruption performance, the arc traveling interruption method (also described in the background art) is adopted in the first embodiment. In this arc travel interruption method, an arc generated at the time of short-circuit interruption is guided to the arc extinguishing device 53 by using an electromagnetic repulsive force, and finally the arc extinguishing device 53 secures a current path by the arc. The arc is cut. Specifically, the arc generated between the contacts 9 and 13 is transferred to the yoke 7 on the fixed contact 9 side and to the arc runner 25 (see FIG. 7) on the movable contact 13 side. Due to this transition, the current path becomes the power source side terminal 5 to the arc runner 25 to the grid 53 a of the arc extinguishing device 53 to the yoke 7 to the coil 18 to the load side terminal 6. The repulsive force of the magnetic field generated when the direction of the electric current of the arc runner 25 (arrow E) and the direction of the electric current from the lower side to the upper side (arrow F) on the paper surface of the grid 53a are different directions, and the arrow F Then, the direction of the current toward the fixing point of the yoke 7 with the fixed contact 9 (arrow G, see FIG. 3) is also different from the direction of the magnetic field, and the arc is caused to the arc extinguishing device 53. Led. The guided arc is cut, and as a result, the large current accompanying the occurrence of this short circuit is quickly cut off.

  As is apparent from the above description, it is necessary to expose the yoke 7 with respect to the stationary contact 9 and the grid 53a, which is realized by the following measures. That is, the first hole 2d is formed in the bottom surface of the middle base 2 to which the overcurrent tripping device 52 is fixed, and the first hole 2d is formed into the yoke 7 by the fixing of the overcurrent tripping device 52. In other words, the uppermost grid 53a of the arc extinguishing device 53 and the yoke 7 are opposed to each other without any inclusions therebetween. The first hole 2d has a narrow portion extending on the right side (on the lower side in FIG. 4A). Both contacts 9 and 13 are inserted into the narrow portion. It is ensured as a turning locus of the movable contact 13. Reference numeral 26 denotes a reflection plate as a pressure receiving part that promotes the opening operation of the movable contact 13 by receiving the expansion pressure of the arc gas, and 27 is a core that promotes the electromagnetic repulsive force. The “blocking portion” indicates, for example, a region constituted by the arc extinguishing device 53 and the arc runner 25 in addition to the reflector 26 and the core 27.

  Another measure concerning the above-mentioned “assistance of the opening operation” will be described here. In FIG. 3, if the hollow portion 22a is provided in the fixed iron core 22 and the rod 28 is provided in contact with or close to the movable iron core 24 in the hollow portion 22a, the movable portion can be moved as described in the background art section. Since the rod 28 strikes the movable contact 13 by the movement of the iron core 24, the contacts 9 and 13 can be quickly separated without waiting for the opening / closing mechanism 51 to operate. In addition to this, in the arc travel interruption system of the first embodiment, as described above, the coil 18 is included in the current path by the arc, so that the movable iron core 24 and, consequently, the rod 28 are still moved by the magnetic force of the coil 18. Since the movable contact 13 remains moving in the direction of opening, the movable contact 13 can be prevented from rotating in the contact direction (so-called swaying back), and high arc voltage can be maintained, that is, rapid arc transfer. Can be planned. Reference numeral 29 denotes a barrier laid between the yoke 7 and the coil 18, and the barrier 29 prevents an appropriate current (arc current) from bypassing the coil 18 not only during current detection but also during arc maintenance. It generates magnetic force.

  As described above, according to the circuit breaker 101 of the present invention, automatic assembly can be realized at the same time while satisfying the basic performance essential for the circuit breaker, that is, stabilization of characteristics and improvement of the breaking performance. This can contribute to a significant profit improvement, especially for small circuit breakers with high cost competitiveness.

1 cover, 2 middle base, 2d first hole, 2e second hole, 3 base,
3e Projection part, 4 Operation handle, 7 Yoke, 7a Bending part, 9 Fixed contact,
12 crossbars, 13 movable contacts, 14 frames,
51 Opening / closing mechanism, 52 Overcurrent tripping device, 53 Arc extinguishing device,
101 Circuit breaker.

Claims (3)

An opening / closing mechanism having an operation handle and disposed between mutually opposed frame plates, a middle base in which an overcurrent tripping device for detecting an overcurrent and rotating the opening / closing mechanism is housed, and the opening / closing mechanism A blocking part including an arc extinguishing device for cutting an arc generated between a movable contact provided on a crossbar that rotates in conjunction with the movable part and a stationary contact that repeats contact with and away from the movable contact is housed. A circuit breaker comprising a base and a cover that covers the middle base, the base, and each component housed in the middle base,
A circuit breaker characterized in that the breaker is covered with the middle base, and the overcurrent tripping device is housed in the middle base by press fitting.   The middle base is provided with a first hole on the surface orthogonal to the direction in which the middle base is inserted into the base so as to be opposed to the blocking portion. The circuit breaker according to claim 1, wherein the circuit breaker is attached by a member constituting the device.   The middle base is provided with a second hole for preventing the overcurrent trip device from floating in the direction opposite to the press-fitting direction in order to fix the overcurrent trip device by press-fitting. 3. The circuit breaker according to claim 1, wherein the second hole is closed by a protrusion provided on the base when the middle base is inserted into the base. 4.

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