Miniature circuit breaker

Abstract

The utility model belongs to the field of circuit breakers, and particularly relates to a miniature circuit breaker, which comprises a shell, an operating mechanism, a moving contact, a static contact, an arc extinguish chamber, a first wiring terminal, a second wiring terminal and an electromagnetic tripping mechanism, the electromagnetic tripping mechanism comprises a magnet yoke, an armature and a torsion spring, the magnet yoke is arranged in the shell, the armature is rotatably arranged on the magnet yoke, and the torsion spring is arranged in the shell. An iron core sheet is arranged between the magnet yoke and the wiring straight plate part, one end of the magnet yoke, corresponding to two sides of the accommodating groove, is vertically bent to form two strip-shaped attraction parts matched with the armature, and one end of the armature is provided with a square attraction part attracted with the two strip-shaped attraction parts; the electromagnetic tripping mechanism adopts a clapping type structural design and can meet the use requirement of a large-current miniature circuit breaker, the magnet yoke adopts a symmetrical magnetic circuit design, magnetic leakage is avoided, a concentrated magnetic field acts on the armature, and the attraction area of the magnet yoke and the armature can be increased, so that the attraction force of the magnet yoke to the armature is stronger, and the tripping action of the armature is more sensitive.

Description

Technical Field

[0001] This utility model belongs to the field of circuit breaker technology, specifically relating to a miniature circuit breaker. Background Technology

[0002] Miniature circuit breakers, also known as micro circuit breakers, are suitable for overload and short-circuit protection of AC 50 / 60Hz lines with a rated voltage of 230 / 400V and a rated current up to 63A. They can also be used for infrequent switching of circuits under normal conditions. Miniature circuit breakers are mainly used in various places such as industrial, commercial, high-rise, and residential buildings. A miniature circuit breaker includes a housing, operating mechanism, contact system, arc extinguishing system, and electromagnetic trip unit. The electromagnetic trip unit's function is to instantly trigger the tripping mechanism through electromagnetic induction when a short-circuit fault occurs (the current instantly surges to several times or even tens of times the rated value), quickly cutting off the circuit and preventing overheating, equipment damage, or fire.

[0003] Most existing electromagnetic trip units for miniature circuit breakers employ a coil structure design. When a short circuit occurs, the moving and stationary iron cores are attracted to each other. The moving iron core pushes the push rod forward, which in turn pushes the latch to release, thus causing the operating mechanism to perform the tripping action. This electromagnetic trip unit occupies a large amount of internal space in the circuit breaker, has a slow tripping action, and cannot meet the requirements for high-current miniature circuit breakers. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide a small circuit breaker that is small in size, has sensitive tripping action, and can meet the requirements of high current use.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A miniature circuit breaker includes a housing, an operating mechanism, a moving contact, a stationary contact, an arc-extinguishing chamber, a first terminal, a second terminal, and an electromagnetic tripping mechanism. The electromagnetic tripping mechanism includes a magnetic yoke, an armature, and a torsion spring. The magnetic yoke is installed inside the housing, and the armature is rotatably mounted on the magnetic yoke. One end of the stationary contact has a straight connecting plate. The magnetic yoke is provided with a receiving groove through which the straight connecting plate passes. The straight connecting plate passes through the receiving groove and is connected to the first terminal. An iron chip is provided between the magnetic yoke and the straight connecting plate. One end of the magnetic yoke is vertically bent at both sides corresponding to the receiving groove to form two strip-shaped attracting parts that cooperate with the armature. One end of the armature is provided with a square attracting part that attracts the two strip-shaped attracting parts.

[0006] In some embodiments, the two strip-shaped suction portions are provided with two suction ramps that attract the square suction portion.

[0007] In some embodiments, the square suction part is provided with a trigger rod part that cooperates with the latch of the operating mechanism, and the latch is provided with a trigger ramp that cooperates with the trigger rod part. The trigger rod part moves with the square suction part and abuts against the trigger ramp surface, thus forming a linkage between the latch and the armature.

[0008] In some embodiments, the other end of the magnetic yoke is provided with a rotating shaft, the other end of the armature is rotatably mounted on the rotating shaft, the torsion spring is fitted on the rotating shaft, and the two torsion arms of the torsion spring respectively abut against the wiring straight plate and the square suction part.

[0009] In some embodiments, an exhaust chamber is provided inside the housing corresponding to the rear side of the arc-extinguishing chamber. A partition is provided inside the exhaust chamber, which divides the exhaust chamber into a first diversion chamber and a second diversion chamber. A lower exhaust hole communicating with the first diversion chamber is provided on the housing, and an upper exhaust hole communicating with the second diversion chamber is provided inside the housing corresponding to the first terminal.

[0010] In some embodiments, the arc-extinguishing chamber is provided with a plurality of exhaust holes on its cover, the plurality of exhaust holes being distributed alternately on the cover, and the plurality of exhaust holes being connected to the exhaust chamber.

[0011] In some embodiments, the housing is provided with an arc-blocking protrusion surrounding the stationary contact of the stationary contact and the moving contact of the moving contact.

[0012] In some embodiments, the stationary contact has an arc-inducing angle at the corresponding stationary contact point, and the tail of the arc-inducing angle extends into the arc-extinguishing chamber.

[0013] In some embodiments, a plurality of arc-inducing protrusions are respectively provided between the arc-isolating protrusion and the arc-extinguishing chamber inside the housing, and a plurality of arc-inducing grooves are formed between the plurality of arc-inducing protrusions.

[0014] In some embodiments, the plurality of arc-initiating protrusions extend in an arc shape from the arc-isolating protrusions toward the arc-extinguishing chamber.

[0015] The beneficial effects of this utility model are as follows: 1. The electromagnetic tripping mechanism adopts a snap-fit ​​structure design, which is simple in design, small in size, and can meet the requirements of high-current miniature circuit breakers. The magnetic yoke is attracted to the armature through two strip-shaped attracting parts. The magnetic yoke adopts a symmetrical magnetic circuit design to avoid magnetic leakage, concentrate the magnetic field on the armature, and increase the attraction area between the magnetic yoke and the armature. As a result, the magnetic yoke has a stronger attraction force on the armature, and the armature tripping action is more sensitive, which helps to improve the sensitivity of the circuit breaker's tripping action. Adding an iron chip between the wiring plate and the magnetic yoke can enhance the effect of the magnetic field on the armature and ensure the sensitivity of the armature's tripping action.

[0016] 2. The casing adopts a diversion and exhaust structure design, which is conducive to the rapid depressurization of the internal air pressure of the circuit breaker and can ensure that the electric arc can quickly enter the arc extinguishing chamber, which is beneficial to improving the arc extinguishing performance of the circuit breaker. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of this utility model.

[0018] Figure 1 This is a perspective view of the internal structure of an embodiment of the present utility model;

[0019] Figure 2 This is a front view of the internal structure of an embodiment of the present utility model;

[0020] Figure 3 This is a cross-sectional view of an embodiment of the present utility model. Detailed Implementation

[0021] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0023] The directional and positional terms used in this utility model, such as up, down, front, back, left, right, inside, outside, top, bottom, side, etc., are only for reference to the accompanying drawings. Therefore, the directional and positional terms used are for the purpose of explaining and understanding this utility model, and not for limiting the scope of protection of this utility model.

[0024] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments:

[0025] like Figure 1 , 3As shown, a miniature circuit breaker includes a housing 10, an operating mechanism 11, a moving contact 12, a stationary contact 13, an arc-extinguishing chamber 14, a first terminal block 15, a second terminal block 16, and an electromagnetic tripping mechanism 20. The electromagnetic tripping mechanism 20 includes a magnetic yoke 21, an armature 22, and a torsion spring 23. The magnetic yoke 21 is installed inside the housing 10, and the armature 22 is rotatably mounted on the magnetic yoke 21. One end of the stationary contact 13 has a straight terminal block 131. The magnetic yoke 21 is provided with a connection point for... The straight section 131 of the wiring terminal passes through the receiving groove 211 and is connected to the first terminal 15. An iron chip 24 is provided between the magnetic yoke 21 and the straight section 131 of the wiring terminal. One end of the magnetic yoke 21 is vertically bent at both sides of the receiving groove 211 to form two strip-shaped attracting parts 212 that cooperate with the armature 22. One end of the armature 22 is provided with a square attracting part 221 that attracts the two strip-shaped attracting parts 212. The electromagnetic tripping mechanism adopts a snap-fit ​​structure design, which is simple in structure, small in size, and can meet the requirements of high-current miniature circuit breakers. The magnetic yoke is attracted to the armature through the two strip-shaped attracting parts. The magnetic yoke adopts a symmetrical magnetic circuit design to avoid magnetic leakage, concentrate the magnetic field on the armature, and increase the attraction area between the magnetic yoke and the armature. As a result, the magnetic yoke has a stronger attraction force on the armature, and the tripping action of the armature is more sensitive, which is beneficial to improving the sensitivity of the tripping action of the circuit breaker. Adding an iron chip between the straight connector and the yoke enhances the effect of the magnetic field on the armature, ensuring the sensitivity of the armature's tripping action. Two strip-shaped engaging portions 212 are provided with two engaging inclined surfaces 2121 that engage with the square engaging portion 221. The engagement of the two strip-shaped engaging portions with the square engaging portion via these inclined surfaces increases the contact area between them, ensuring reliable engagement and improving the reliability of the electromagnetic tripping mechanism. The square engaging portion 221 is provided with a trigger rod portion 2211 that cooperates with the latch 111 of the operating mechanism 11. The latch 111 is provided with a trigger inclined surface 112 that cooperates with the trigger rod portion 2211. The trigger rod portion 2211 moves with the square engaging portion 221 and abuts against the trigger inclined surface 112, forming a linkage between the latch 111 and the armature 22. The square engaging part triggers the latch via the trigger rod, preventing jamming between the armature and the latch, thus improving the tripping sensitivity of the miniature circuit breaker. A rotating shaft 25 is located at the other end of the magnetic yoke 21, and the other end of the armature 22 is rotatably mounted on the rotating shaft 25. A torsion spring 23 is fitted onto the rotating shaft 25, with its two torsion arms abutting against the wiring straight plate 131 and the square engaging part 221, respectively. The armature's rotatable mounting on the magnetic yoke's rotating shaft ensures its flexible rotation on the yoke, further enhancing the sensitivity of the armature's tripping action.

[0026] like Figure 1 , 2As shown in Figure 3, an exhaust chamber 100 is provided inside the housing 10 at the rear side of the arc-extinguishing chamber 14. A partition 101 is provided inside the exhaust chamber 100, dividing it into a first diversion chamber 102 and a second diversion chamber 103. A lower exhaust port 104 communicating with the first diversion chamber 102 is provided on the housing 10, and an upper exhaust port 105 communicating with the second diversion chamber 103 is provided inside the housing 10 at the location corresponding to the first terminal 15. The diversion exhaust structure design inside the housing facilitates rapid pressure relief inside the circuit breaker and ensures that the arc can quickly enter the arc-extinguishing chamber, thus improving the arc-extinguishing performance of the circuit breaker. Multiple exhaust ports 142 are provided on the cover 141 of the arc-extinguishing chamber 14, and these ports are staggered and connected to the exhaust chambers 100. The exhaust vents of the arc-extinguishing chamber adopt a staggered distribution structure design. This staggered distribution disperses the emission paths of high-temperature gas and arc decomposition products, preventing the formation of localized high-pressure or low-pressure zones due to concentrated airflow. This reduces turbulence and backflow, thereby improving the arc-extinguishing performance of the circuit breaker. An arc-isolating protrusion 106 is provided inside the housing 10, surrounding the stationary contact 130 of the stationary contact 13 and the moving contact 120 of the moving contact 12. The arc-isolating protrusion serves to isolate the arc, preventing it from propagating back towards the operating mechanism and ensuring that the arc can quickly enter the arc-extinguishing chamber. The stationary contact 13 has an arc-initiating angle 132 corresponding to the stationary contact 130, with its tail extending into the arc-extinguishing chamber 14. The arc-initiating angle allows the arc to be quickly introduced into the arc-extinguishing chamber, preventing the arc from burning the stationary contact. Multiple arc-initiating protrusions 107 are respectively provided inside the housing 10 between the arc-isolating protrusions 106 and the arc-extinguishing chamber 14, and multiple arc-initiating grooves 108 are formed between the multiple arc-initiating protrusions 107. The arc-initiating grooves can quickly introduce the arc into the arc-extinguishing chamber, which is conducive to the rapid extinguishing of the arc. The multiple arc-initiating protrusions 107 extend in an arc shape from the arc-isolating protrusions 106 toward the arc-extinguishing chamber 14. The arc-shaped structure design of the arc-initiating protrusions is conducive to increasing the contact area between the arc-initiating protrusions and the arc, which is beneficial to the cooling of the arc.

[0027] The above description is only one embodiment of the present utility model and is not intended to limit the scope of protection of the present utility model; the scope of protection of the present utility model is defined by the claims in the claims, and all equivalent changes and modifications made in accordance with the utility model are within the scope of protection of the present utility model patent.

Claims

1. A miniature circuit breaker, comprising a housing, an operating mechanism, a moving contact, a stationary contact, an arc-extinguishing chamber, a first terminal block, a second terminal block, and an electromagnetic tripping mechanism, characterized in that: The electromagnetic tripping mechanism includes a magnetic yoke, an armature, and a torsion spring. The magnetic yoke is installed inside the housing, and the armature is rotatably mounted on the magnetic yoke. One end of the stationary contact has a straight connecting plate. The magnetic yoke has a receiving groove through which the straight connecting plate passes. The straight connecting plate passes through the receiving groove and is connected to the first terminal. An iron chip is provided between the magnetic yoke and the straight connecting plate. One end of the magnetic yoke is vertically bent at both sides of the receiving groove to form two strip-shaped attracting parts that cooperate with the armature. One end of the armature has a square attracting part that attracts the two strip-shaped attracting parts.

2. The miniature circuit breaker according to claim 1, characterized in that: The two strip-shaped suction parts are provided with two suction slopes that attract the square suction part.

3. The miniature circuit breaker according to claim 1 or 2, characterized in that: The square suction part is provided with a trigger rod part that cooperates with the latch of the operating mechanism. The latch is provided with a trigger slope that cooperates with the trigger rod part. The trigger rod part moves with the square suction part and abuts against the trigger slope surface, thus forming a linkage between the latch and the armature.

4. The miniature circuit breaker according to claim 1 or 2, characterized in that: The magnetic yoke has a rotating shaft at the other end, the armature is rotatably mounted on the rotating shaft at the other end, and the torsion spring is fitted on the rotating shaft. The two torsion arms of the torsion spring respectively abut against the straight part of the wiring and the square suction part.

5. The miniature circuit breaker according to claim 1, characterized in that: An exhaust chamber is provided inside the housing corresponding to the rear side of the arc-extinguishing chamber. A partition is provided inside the exhaust chamber, which divides the exhaust chamber into a first diversion chamber and a second diversion chamber. A lower exhaust hole connected to the first diversion chamber is provided on the housing, and an upper exhaust hole connected to the second diversion chamber is provided inside the housing corresponding to the first terminal.

6. The miniature circuit breaker according to claim 5, characterized in that: The arc-extinguishing chamber has multiple exhaust holes on its cover, which are distributed alternately on the cover and are connected to the exhaust chamber.

7. The miniature circuit breaker according to claim 5, characterized in that: The housing is provided with an arc-blocking protrusion surrounding the stationary contact of the stationary contact and the moving contact of the moving contact.

8. The miniature circuit breaker according to claim 7, characterized in that: The stationary contact has an arc-inducing angle at the corresponding stationary contact point, and the tail of the arc-inducing angle extends into the arc-extinguishing chamber.

9. The miniature circuit breaker according to claim 7, characterized in that: Multiple arc-initiating protrusions are respectively provided between the arc-isolating protrusions and the arc-extinguishing chamber inside the shell, and multiple arc-initiating grooves are formed between the multiple arc-initiating protrusions.

10. The miniature circuit breaker according to claim 9, characterized in that: The multiple arc-initiating protrusions extend in an arc shape from the arc-isolating protrusions toward the arc-extinguishing chamber.

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