An instantaneous protection mechanism for DC circuit breaker

Abstract

The present invention provides an instantaneous protection mechanism for a DC circuit breaker, including an incoming line terminal, a lock, a tripping buckle, a contact base, a torsion spring, a shaft, a moving contact, a static contact, a coil, an iron core, and a permanent magnet; the iron core is fixed to the upper end of the static contact; the right end of the coil is sleeved on the iron core and fixed to the upper end of the static contact; the other end is fixed to the incoming line terminal; the permanent magnet is fixed to the left side of the lock directly opposite the iron core. When a DC short-circuit current passes through the coil, the coil will generate a very strong magnetic field with a constant direction and quickly magnetize the iron core, so that the polarity of the right end of the iron core is the same as the polarity of the left end of the permanent magnet. Due to the principle of like poles repelling each other, the lock is unlocked under the drive of the permanent magnet, and then the circuit breaker realizes instantaneous protection, and it can be realized by adjusting the number of turns of the coil according to different rated currents and different tripping current multiples. The present invention has a simple structure, reduces the types and quantities of parts, makes the protection mechanism more reliable, and greatly improves the assembly efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of circuit breakers, and in particular to an instantaneous protection mechanism of a direct current circuit breaker. Background Art

[0002] A circuit breaker is a mechanical switch that can connect, carry and disconnect current under normal circuit conditions, and can also connect, carry for a certain period of time and disconnect current under specified abnormal conditions. Therefore, it is widely used in power distribution systems. With the continuous development of DC power systems in recent years, DC circuit breakers are used more and more widely. The traditional DC circuit breaker instantaneous protection mechanism is usually composed of coils, moving iron cores, static iron cores, reaction springs, push rods, yokes, coil frames and other parts. When the DC short-circuit current passes through the coil, the moving iron core moves toward the static iron core under the magnetic field generated by the coil, thereby driving the push rod to move, and then the mechanism is unlocked to achieve the short-circuit protection function. Due to the requirements of different rated currents and different tripping current multiples, there are many types of coils and springs in traditional instantaneous protection mechanisms, which makes production control difficult. Summary of the invention

[0003] To solve the above problems, the purpose of the present invention is to provide an instantaneous protection mechanism for a DC circuit breaker which has a simple structure, more stable performance, can significantly reduce assembly time, and only requires adjusting the number of coil turns according to different rated currents and different tripping current multiples.

[0004] The purpose of the present invention is achieved through the following technical solutions:

[0005] A transient protection mechanism for a DC circuit breaker comprises an incoming line terminal, a lock, a trip button, a contact base, a torsion spring, a shaft, a moving contact and a stationary contact installed inside a circuit breaker housing; the middle part of the lock is rotatably installed on the shaft (for limiting the rotation of the trip button, and further limiting the rotation of the moving contact), and its right side is concave to form a cavity; the left end of the trip button is snap-connected with the upper part of the lock button (the top of the left end of the trip button is snap-fitted with the bottom of the upper right corner of the lock button), and the right end is connected to the upper right part of the contact base through a rivet; the middle part of the contact base is rotatably installed on the shaft; one end of the torsion spring is placed on the contact base, and the other end is placed on the lock button to provide a reset force value for the lock button; after the moving contact is connected to the contact base, it is installed together in the cavity of the lock button, the upper part of the moving contact is sleeved on the shaft, and the middle part of the moving contact is installed in the contact base and can rotate with the contact base; the right side of the stationary contact is in contact with the lower left part of the moving contact. The instantaneous protection mechanism of the DC circuit breaker also includes a coil, an iron core, and a permanent magnet; the iron core is transversely fixed to the upper end of the static contact corresponding to the lower left side of the lock; the right end of the coil is sleeved on the iron core (transversely) and fixedly connected to the upper end of the static contact; the other end is fixedly connected to the incoming line terminal; the permanent magnet is fixed to the lower left side of the lock opposite to the iron core, and the left side of the permanent magnet is the N pole. The limitations on the positions and connection relationships of the above-mentioned components are described based on the premise that the circuit breaker is in the closed state and the tripping buckle is buckled with the lock.

[0006] When the circuit breaker is closed and the trip button and the lock button are engaged, the DC short-circuit current flows into the coil from the incoming line end. The coil generates a very strong magnetic field with a constant direction. The magnetic field quickly magnetizes the iron core. According to Ampere's law (right-hand screw rule), the right side of the iron core is the N pole, and because the left side of the permanent magnet is also the N pole, according to the principle of like poles repel, the permanent magnet (will be subject to an electromagnetic repulsion to the right (of course, the iron core will also be subject to it, but the iron core is fixed and it is difficult for this electromagnetic repulsion to move it). In this electric Under the action of magnetic repulsion, the permanent magnet will move to the right and push the lock buckle to overcome the reaction force of the torsion spring and rotate counterclockwise around the shaft, so that the trip buckle (6) loses the buckle surface, that is, the lock buckle and the trip buckle are disengaged, unlocked, and the trip buckle and the moving contact (are in a rotatable state. After the lock buckle and the trip buckle are disengaged, the electromagnetic repulsion force continues to act on the lock buckle, pushing the lock buckle to continue to rotate counterclockwise and contact the moving contact and push the lower part of the moving contact to rotate to the right, so that the moving contact is separated from the static silver point, and the circuit breaker is opened, that is, the circuit breaker short-circuit protection is realized.

[0007] Furthermore, a static silver point is fixed at a position on the static contact that contacts the moving contact to enhance the contact effect and improve the current conduction efficiency.

[0008] Furthermore, the static silver point and the static contact, the coil and the static contact, and the coil and the incoming line end are all fixed by welding; the iron core and the static contact are fixed by riveting.

[0009] Furthermore, the material used for the permanent magnet is NdFe35.

[0010] Furthermore, the material used for the iron core is soft magnetic material.

[0011] Furthermore, in order to prevent the permanent magnet from loosening and shifting, the permanent magnet is fixed by a buckle arranged on the lock buckle.

[0012] Furthermore, a foolproof structure 1 is provided on the permanent magnet, and a foolproof structure 2 is provided on the lock buckle to match the foolproof structure 1; the foolproof structure 1 and the foolproof structure 2 can prevent the permanent magnet from being installed incorrectly, resulting in the reverse installation of the magnetic poles. When the permanent magnet is installed in the reverse direction, it cannot be installed in place to ensure the left polarity of the permanent magnet.

[0013] Compared with the traditional instantaneous protection mechanism, the instantaneous protection mechanism of the present invention saves the moving iron core, reaction spring, magnetic yoke, push rod, coil frame and other parts, and different rated currents are achieved by adjusting the number of coil turns.

[0014] Under the working conditions of rated current 20A, number of coil turns: 7 turns, tripping current multiple: 10*In, permanent magnet material is NdFe35, and the gap between the iron core and the permanent magnet is 0.7mm, by using the electromagnetic field analysis tool Ansys-maxwell electromagnetic simulation module for simulation calculation, the magnetic flux on the right side of the iron core (axial direction of the iron core) Φm=3.896e-6Wb, the magnetic flux on the left side of the permanent magnet (axial direction of the iron core) Φm=-9.835e-7Wb, the electromagnetic repulsion: 1.01N, and the tripping force of ordinary small circuit breakers can generally be controlled between 0.5-0.8N, so this electromagnetic repulsion can meet the tripping requirements.

[0015] The present invention has a simple structure and eliminates materials such as a moving iron core, a yoke, a reaction spring, a push rod, and a coil frame compared to a traditional instantaneous protection mechanism. It has more stable performance and can greatly reduce assembly time. In addition, it only requires adjusting the number of turns of the coil according to different rated currents and different tripping current multiples, making it easier to control materials and production, and making production faster and more convenient, thereby making the product more competitive in the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0017] Figure 2 It is a schematic diagram of the overall cross-sectional structure of the present invention;

[0018] Figure 3 It is a schematic diagram of the installation structure of the lock buckle and the permanent magnet in the present invention;

[0019] Figure 4 It is a schematic diagram of the installation structure of the coil, the iron core, the static contact and the static silver point in the present invention;

[0020] Figure 5 It is a schematic diagram of the structure of the lock in the present invention;

[0021] As shown in the figure: 1-incoming terminal, 2-coil, 3-iron core, 4-permanent magnet, 401-anti-foolproof structure one, 5-lock, 501-clip, 502-anti-foolproof structure two, 6-jump buckle, 7-rivet, 8-contact base, 9-torsion spring, 10-shaft rod, 11-moving contact, 12-static silver point, 13-static contact. DETAILED DESCRIPTION

[0022] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0023] It should be noted that the structures, proportions, sizes, etc. drawn in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and so on quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content. Embodiment 1

[0024] like Figures 1 to 5The instantaneous protection mechanism of a DC circuit breaker of the present invention comprises an incoming line terminal 1, a lock buckle 5, a jump buckle 6, a contact base 8, a torsion spring 9, a shaft rod 10, a moving contact 11, and a stationary contact 13 installed inside the circuit breaker housing; the middle part of the lock buckle 5 is rotatably installed on the shaft rod 10 (for limiting the rotation of the jump buckle 6, and further limiting the rotation of the moving contact 11), and the right side thereof is concave to form a cavity; the left end of the jump buckle 6 is snap-connected with the upper part of the lock buckle 5 (the top of the left end of the jump buckle 6 is snap-fitted with the bottom of the upper right corner of the lock buckle 5), and the right end is connected to the upper right part of the contact base 8 through a rivet 7; The middle part of the contact base 8 is rotatably mounted on the shaft 10; one end of the torsion spring 9 is placed on the contact base 8, and the other end is placed on the lock buckle 5 to provide a reset force for the lock buckle 5; the moving contact 11 is connected to the contact base 8 and is installed in the cavity of the lock buckle 5 together, the upper part of the moving contact 11 is sleeved on the shaft 10, and the middle part of the moving contact 11 is installed in the contact base 8 and can rotate with the contact base 8; the right side 13 of the static contact is in contact with the lower left part of the moving contact 11; a static silver point 12 is welded at the position of the static contact 13 in contact with the moving contact 11 to enhance the contact effect and improve the current conduction efficiency. The instantaneous protection mechanism of the DC circuit breaker also includes a coil 2, an iron core 3, and a permanent magnet 4; the iron core 3 is riveted horizontally to the upper end of the static contact 13 corresponding to the lower left side of the lock buckle 5, and the material used for the iron core 3 is a soft magnetic material; the right end of the coil 2 (horizontally) is sleeved on the iron core 3 and welded to the upper end of the static contact 13; the other end is welded to the incoming line terminal 1; the permanent magnet 4 is fixed to the lower left side of the lock buckle 5 opposite the iron core 3, the left side of the permanent magnet 4 is the N pole, and the material used for the permanent magnet 4 is NdFe35. The above-mentioned limitations on the position and connection relationship of each component are described based on the premise that the circuit breaker is in the closed state and the trip buckle 6 is buckled with the lock buckle 5.

[0025] like Figure 1 , Figure 2As shown in the figure, when the circuit breaker is closed and the trip button 6 is engaged with the lock button 5, the DC short-circuit current flows from the incoming line terminal 1 into the coil 2, and the coil 2 generates a very strong magnetic field with a constant direction, which quickly magnetizes the iron core 3. According to Ampere's law (right-hand screw rule), the right side of the iron core 3 is the N pole, and because the left side of the permanent magnet 4 is also the N pole, according to the principle of like poles repel, the permanent magnet 4 will be subjected to an electromagnetic repulsion to the right (of course, the iron core 3 will also be subjected to it, but the iron core 3 is fixed and it is difficult for this electromagnetic repulsion to move it). Under this electromagnetic repulsion Under the action, the permanent magnet 4 will move to the right and push the lock buckle 5 to overcome the reaction force of the torsion spring 9 and rotate counterclockwise around the shaft 10, so that the jump buckle 6 loses the buckle surface, that is, the lock buckle 5 is disengaged from the jump buckle 6, unlocked, and the jump buckle 6 and the moving contact 11 are in a rotatable state. After the electromagnetic repulsive force disengages the lock buckle 5 from the jump buckle 6, it continues to act on the lock buckle 5, pushing the lock buckle 5 to continue to rotate counterclockwise to contact the moving contact 11 and push the lower part of the moving contact 11 to rotate to the right, so that the moving contact 11 is separated from the static silver point 12, and the circuit breaker is opened, that is, the circuit breaker short-circuit protection is realized.

[0026] Compared with the traditional instantaneous protection mechanism, the instantaneous protection mechanism of the present invention omits the moving iron core, reaction spring, magnetic yoke, push rod, coil skeleton and other parts, and different rated currents are achieved by adjusting the number of turns of coil 2. Under the working conditions of rated current 20A, number of turns of coil 2: 7 turns, tripping current multiple: 10*In, permanent magnet 4 material is NdFe35, and the gap between iron core 3 and permanent magnet 4 is 0.7mm, by using the electromagnetic field analysis tool Ansys-maxwell electromagnetic simulation module to perform simulation calculation, the magnetic flux of the right side of iron core 3 (axial direction of iron core) Φm=3.896e-6Wb, the magnetic flux of the left side of permanent magnet 4 (axial direction of iron core) Φm=-9.835e-7Wb, and the electromagnetic repulsion force: 1.01N, while the tripping force of ordinary small circuit breakers can generally be controlled between 0.5-0.8N, so the electromagnetic repulsion can meet the tripping requirements. Embodiment 2

[0027] The difference between this embodiment and the first embodiment is that: Figure 3 , Figure 5 As shown, the permanent magnet 4 is fixed by a buckle 501 arranged on the lock buckle 5, and the buckle 501 can prevent the permanent magnet 4 from loosening and shifting. Embodiment 3

[0028] The difference between this embodiment and the second embodiment is that: Figure 4 As shown, a foolproof structure 1 401 is provided on the permanent magnet 4, and a foolproof structure 2 502 is provided on the lock buckle 5 to match the foolproof structure 1 401; the foolproof structure 1 401 and the foolproof structure 2 502 can prevent the permanent magnet 4 from being installed incorrectly, resulting in the reversed magnetic poles. When the permanent magnet 4 is installed in the reverse direction, it cannot be installed in place to ensure the left polarity of the permanent magnet 4.

[0029] The protection scope of the present invention is not limited to the technical solutions disclosed in the specific implementation methods. Any modifications, equivalent replacements, improvements, etc. made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. An instantaneous protection mechanism for a DC circuit breaker, comprising an incoming line terminal (1), a lock catch (5), a trip catch (6), a contact base (8), a torsion spring (9), a shaft (10), a moving contact (11), and a stationary contact (13) installed inside a circuit breaker housing; the middle portion of the lock catch (5) is rotatably installed on the shaft catch (10), and its right side is concave to form a cavity; the left end of the trip catch (6) is snap-connected with the upper portion of the lock catch (5), and the right end is connected to the upper right portion of the contact base (8) through a rivet (7); the middle portion of the contact base (8) is rotatably installed on the shaft catch (10); one end of the torsion spring (9) is placed on the contact base (8), and the other end is placed on the lock catch (5); the moving contact (11) is installed in the cavity of the lock catch (5) after being connected to the contact base (8); the right side (13) of the stationary contact is in contact with the lower left portion of the moving contact (11); and the characteristics are: It also includes a coil (2), an iron core (3), and a permanent magnet (4); the iron core (3) is transversely fixed to the upper end of the static contact (13) corresponding to the lower left side of the lock buckle (5); the right end of the coil (2) is sleeved on the iron core (3) and fixedly connected to the upper end of the static contact (13); the other end is fixedly connected to the incoming line terminal (1); the permanent magnet (4) is fixed to the lower left side of the lock buckle (5) opposite to the iron core (3), the left side of the permanent magnet (4) is an N pole, the permanent magnet (4) is fixed by a buckle (501) arranged on the lock buckle (5), a foolproof structure 1 (401) is arranged on the permanent magnet (4), and a foolproof structure 2 (502) matching the foolproof structure 1 (401) is correspondingly arranged on the lock buckle (5); a static silver point (12) is fixed at a position on the static contact (13) that contacts the moving contact (11); When the circuit breaker is closed and the trip button (6) is engaged with the lock button (5), a DC short-circuit current flows from the incoming line terminal (1) into the coil (2), and the coil (2) generates a magnetic field with a constant direction. This magnetic field magnetizes the iron core (3). According to Ampere's law, the right side of the iron core (3) is the N pole, and the left side of the permanent magnet (4) is also the N pole. According to the principle that like poles repel each other, the permanent magnet (4) is subjected to an electromagnetic repulsive force to the right, and the iron core (3) is fixed. Under the action of this electromagnetic repulsive force, the permanent magnet (4) moves to the right and pushes the lock button (5) to overcome the reaction force of the torsion spring (9) and rotate counterclockwise around the shaft (10). The trip buckle (6) is rotated, causing the trip buckle (6) to lose its buckle surface, the lock buckle (5) and the trip buckle (6) to be disengaged and unlocked, and the trip buckle (6) and the moving contact (11) are in a rotatable state. After the lock buckle (5) and the trip buckle (6) are disengaged, the electromagnetic repulsive force continues to act on the lock buckle (5), pushing the lock buckle (5) to continue to rotate counterclockwise to contact the moving contact (11) and push the lower part of the moving contact (11) to rotate rightward, so that the moving contact (11) is separated from the static silver point (12), and the circuit breaker is opened, that is, the circuit breaker short-circuit protection is realized; and different rated currents and different tripping current multiples are achieved by adjusting the number of turns of the coil (2).

2. The instantaneous protection mechanism of a DC circuit breaker according to claim 1, characterized in that: The static silver point (12) and the static contact (13), the coil (2) and the static contact (13), and the coil (2) and the incoming line terminal (1) are all fixed by welding; the iron core (3) and the static contact (13) are fixed by riveting.

3. The instantaneous protection mechanism of a DC circuit breaker according to claim 1, characterized in that: The material used for the permanent magnet (4) is NdFe35.

4. The instantaneous protection mechanism of a DC circuit breaker according to claim 1, characterized in that: The material used for the iron core (3) is a soft magnetic material.

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