A static contact structure, contact system and circuit breaker

Abstract

The present invention relates to the technical field of circuit breakers, and in particular to a static contact structure, a contact system and a circuit breaker, wherein the static contact structure comprises a body part, which comprises at least one group of body parts and at least two shunt parts, any group of body parts comprises two connecting parts that are opposite and spaced apart, the shunt parts are arranged side by side between the two connecting parts and are respectively connected to the two connecting parts; the contact part is connected to the connecting part of the body part close to the moving contact, and can be in contact with the moving contact to form a conductive circuit; when current passes through the conductive circuit, the direction of the current flowing through all the shunt parts and the moving contacts is the same and opposite to the direction of the current flowing through the contact part; the moving contact is subjected to an electric force F L Equal to the electric repulsion F of the contact head on the moving contact L1 The electric suction force F of the moving contact with all shunt parts L2i The sum of F L =F L1 +F L21 +F L22 +…+F L2i ; where i is an integer ≥ 2. Improve short-term tolerance and is suitable for selective protection environment.

Description

Technical Field

[0001] The invention belongs to the technical field of circuit breakers, and in particular relates to a static contact structure, a contact system and a circuit breaker. Background Art

[0002] A circuit breaker is a switch device that can connect, carry and disconnect the current of a normal circuit within a specified time, and can also carry and disconnect the current under abnormal circuit conditions (such as overload, short circuit, undervoltage and single-phase grounding fault). With the development of science and technology, people's living standards are improving, the demand for electricity is increasing, and the requirements for circuit breakers that play a protective role in the circuit are getting higher and higher. It is hoped that the circuit breaker is small in size, light in weight, and can break a larger amount of electricity.

[0003] Inside the circuit breaker, there is a contact system consisting of a moving contact and a stationary contact that can perform on-off operations. In the existing common contact system, the moving contact and the stationary contact are arranged at one end of the stationary contact and are roughly parallel. The current direction of the stationary contact at one end of the stationary contact is opposite to the current direction of the moving contact. When the current passes through, the moving contact is separated from the stationary contact by the electric repulsion, generating an arc, thereby limiting the further increase of the short-circuit current. Then the electromagnetic protection mechanism of the circuit breaker will drive the operating mechanism to operate, so that the circuit breaker trips and opens, extinguishes the arc, and cuts off the short-circuit fault current. However, in the case of a short-circuit fault in the existing contact system, the peak value of the short-circuit current often reaches hundreds of kiloamperes. Such a large current flowing through the conductive circuit of the circuit breaker will generate a large electric repulsion between the moving and stationary contacts, and the moving contact and the stationary contact will quickly repel each other, and the short-term tolerance capacity is relatively low. In an environment where selective protection is required, it is difficult to achieve the expected effect due to the too early repulsion. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the technical problem that the short-time withstand capability of the moving and stationary contacts of the circuit breaker in the prior art is relatively low, thereby providing a stationary contact structure capable of improving the short-time withstand capability, a contact system having the stationary contact structure and a circuit breaker.

[0005] To this end, an object of the present invention is to provide a stationary contact structure, comprising:

[0006] The main body comprises at least one group of main body parts and at least two diverter parts, wherein each group of the main body parts comprises two connecting parts that are opposite and spaced apart, and the diverter parts are arranged side by side between the two connecting parts and are respectively connected to the two connecting parts;

[0007] A contact part connected to the connecting part of the main body close to the moving contact, and capable of contacting and conducting with the moving contact to form a conductive circuit;

[0008] When current flows through the conductive loop, the direction of the current flowing through all the shunt parts and the moving contacts is the same and opposite to the direction of the current flowing through the contact parts;

[0009] The moving contact is subjected to an electric force F L Equal to the electromotive force F of the contact head on the moving contact L1 The electric suction force F of all the shunt parts on the moving contact L2i the sum of

[0010] F L =F L1 +F L21 +F L22 +…+F L2i ; where i is an integer ≥2.

[0011] Preferably, in the static contact structure, at least two of the shunt parts are connected in parallel and connected in series with the main body.

[0012] Preferably, in the static contact structure, the main body comprises at least two groups, and the at least two groups of main body are connected in parallel;

[0013] At least two groups of the main body parts are arranged at intervals to form an escape space for the switching activities of the moving contact and the contact part.

[0014] Preferably, in the static contact structure, any group of the main body parts is provided with at least three shunt parts, and the resistance of at least one of the at least three shunt parts is different from the resistance of the other shunt parts.

[0015] Preferably, in the static contact structure, the resistances of all the shunt parts are the same.

[0016] Preferably, in the static contact structure, a bending portion bent toward the diverter portion is formed at one end of the contact portion away from the connecting portion; and / or

[0017] All the diversion parts are arranged in parallel and perpendicular to the connecting part.

[0018] Preferably, the static contact structure further includes:

[0019] A connector portion, which is arranged on the connecting portion at one end of the main body away from the moving contact, and has an extending direction consistent with that of the contact portion, both extending in a direction away from the moving contact;

[0020] The direction of the current flowing through the joint portion is the same as the direction of the current flowing through the shunt portion and the moving contact, and is opposite to the direction of the current flowing through the contact portion.

[0021] Preferably, in the static contact structure, the main body portion, the diverter portion, the contact portion and the joint portion are integrally formed.

[0022] Another object of the present invention is to provide a contact system, comprising a movable contact assembly and a stationary contact assembly capable of contacting and conducting, wherein the stationary contact assembly comprises any of the stationary contact structures described above.

[0023] Another object of the present invention is to provide a circuit breaker comprising the contact system.

[0024] The technical solution of the present invention has the following advantages:

[0025] 1. The static contact structure provided by the present invention has a shunt part in the static contact structure. The current direction of the shunt part is the same as the current direction of the moving contact and opposite to the current direction of the contact part. According to the principle that currents in the same direction of conductors attract each other and currents in opposite directions repel each other, when a short circuit occurs in the conductive circuit, the moving contact is subjected to the electric suction force exerted by the shunt part and the electric repulsion force exerted by the contact part. According to the electromotive force formula, it can be known that the electromotive force is proportional to the square of the current. Since the shunt part is provided, the electric suction force exerted on the moving contact by all the shunt parts is compared with the electric suction force when the shunt part is not provided, which delays the time for the moving contact and the static contact to be segmented, thereby improving the short-time tolerance capability and being suitable for selective protection environments.

[0026] 2. In the static contact structure provided by the present invention, a bending portion is formed at one end of the contact portion away from the connecting portion and bent toward the diverter portion. The bending portion can help the arc to move upward quickly, reducing the ablation of the contact, and protecting the contact system.

[0027] 3. The static contact structure provided by the present invention further comprises a joint portion, through which the static contact structure can be fixedly installed in the housing of the circuit breaker.

[0028] 4. The static contact structure provided by the present invention has a main body, a shunt part, a contact part and a joint part formed in one piece, which is convenient for processing and manufacturing, has a low manufacturing cost, and the overall structure and conduction performance of the static contact structure are relatively reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1is a schematic structural diagram of a stationary contact structure in Embodiment 1 of the present invention;

[0031] Figure 2 It is a structural schematic diagram of the contact system in Example 2 of the present invention when the moving contact is electrically powered and separated from the stationary contact structure.

[0032] Description of reference numerals:

[0033] 1-static contact structure; 10-body; 11-main body; 111-connecting part; 12-shunt part; 13-contact part; 14-connector part;

[0034] 2- Moving contact. DETAILED DESCRIPTION

[0035] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Example 1

[0037] The static contact structure 1 of this embodiment, see Figure 1 to Figure 2 As shown, it includes a body part 10, a contact part 13 and a joint part 14. The body part 10 includes at least one group of body parts 11 and at least two diverter parts 12, and any group of body parts 11 includes two connecting parts 111 that are opposite and spaced apart. Figure 1 The two vertically spaced vertical parts shown in FIG. 1 are arranged side by side between the two connecting parts 111 and are connected to the two connecting parts 111 respectively. The two dividing parts 12 are also as shown in FIG. Figure 1 The two lateral portions shown are arranged between the connecting portions 111 of the two vertical portions. The contact portion 13 is connected to the connecting portion 111 of the main body 11 close to the moving contact 2, that is, Figure 2 The horizontally extending portion extending to the left below the connecting portion 111 at the right end of the static contact structure 1 shown can be in contact with the moving contact 2 to form a conductive circuit, that is, the static contact is provided on the contact portion 13, which is used to connect with the moving contact on the moving contact 2 to achieve the main circuit conduction. The joint portion 14 is arranged on the connecting portion 111 of the main body 11 away from the moving contact 2, that is, Figure 2 A through hole is provided on the joint portion 14 at the lower left side of the connection portion 111 at the left end of the static contact structure 1 shown in the figure, which is used to connect the static contact structure 1 to the housing (not shown) of the circuit breaker so as to be fixedly installed in the housing. When current flows through the conductive circuit, the direction of the current flowing through all the shunt portions 12 and the moving contact 2 is the same and opposite to the direction of the current flowing through the contact portion 13. Specifically, as shown in FIG. Figure 2 The current shown flows from the joint part 14 to the connecting part 111 on the left and flows to the two shunt parts 12 respectively, and then merges into the contact part 13 from the connecting part 111 on the right, and the current direction changes. The current flows from the static contact to the moving contact 2 through the moving contact, and the current direction changes again, that is, the current direction on the moving contact 2 is the same as the current direction flowing through the joint part 14 and the shunt part 12. The electric force is divided into electric repulsion and electric attraction. The moving contact 2 of the present application is simultaneously subjected to the electric repulsion and electric attraction of the static contact structure 1 on the moving contact 2. Specifically, when the switch is closed, the moving contact 2 is located between the contact part 13 and the shunt part 12. According to the mutual attraction of the same-direction currents of the conductors and the mutual repulsion of the opposite-direction currents, all the shunt parts 12 generate electric attraction on the moving contact 2, and the contact part 13 generates electric repulsion on the moving contact 2, and the directions of the electric attraction and the electric repulsion are the same and both upward, that is, the moving contact 2 is subjected to the electric force F L Equal to the electric repulsion F of the contact part 13 on the moving contact 2 L1 The electric suction force F of all the shunt parts 12 on the moving contact 2 L2i The sum of F L =F L1 +F L21 +F L22 +…+F L2i ; where i is an integer ≥2.

[0038] According to the electromotive force formula:

[0039] Where μ0 represents the magnetic permeability in a vacuum environment; k represents the conductive loop coefficient; and i represents the current in the conductive loop.

[0040] That is to say, the electric force is directly proportional to the square of the current. The present application provides at least two shunts 12, and uses the shunts 12 to shunt the current in the conductive circuit. The current of each shunt 12 is smaller than the current in the total conductive circuit, so that the electric suction force of each shunt 12 on the moving contact 2 is smaller than the electric force of the main body 10 on the moving contact 2 when the shunt 12 is not provided, and the sum of the electric suction forces of all the shunts 12 on the moving contact 2 is also smaller than the sum of the electric forces of the main body 10 on the moving contact 2 when the shunt 12 is not provided.

[0041] Specifically, Figure 1As shown, the main body 10 is provided with two shunt parts 12. The two shunt parts 12 are arranged in parallel and spaced apart between two connecting parts 111 arranged vertically at intervals on the left and right. The two shunt parts 12 are arranged in parallel and connected in series with the two connecting parts 111 of the main body 11 to form a main conductive circuit. If the resistance of the two shunt parts 12 is the same, the current flowing through the main conductive circuit is In. According to the equal voltage, equal resistance and equal current of the parallel circuit, the current flowing through each shunt part 12 is 1 / 2In. According to the above-mentioned electromotive force formula, it can be calculated that the sum of the electromotive repulsion of the two shunt parts 12 on the moving contact 2 is equal to 1 / 2 of the electromotive repulsion of the main body 10 on the moving contact 2 when the shunt part 12 is not provided. Therefore, by adding the shunt part 12, the electric repulsion of the main body 10 on the moving contact 2 is appropriately reduced, thereby reducing the electric force on the moving contact 2, avoiding the excessive electric force on the moving contact 2 caused by the instantaneous increase of the current when a short circuit fault occurs in the conductive circuit, causing the moving contact 2 to be immediately separated and disconnected from the contact part 13, thereby improving the short-time tolerance capacity of the contact system, which is very suitable for selective protection environments.

[0042] Specifically, at least two shunt portions 12 are connected in parallel and in series with the main body 11. That is, the two connecting portions 111 of the main body 11 respectively constitute the current inflow end and the current outflow end of the main circuit in the conductive circuit.

[0043] In order to verify the tolerance capacity of the static contact structure in this embodiment, the inventor conducted the following verification. For the DC molded case circuit breaker of this embodiment, the voltage is DC1500V and the current is 400A. The multiple relationships between the electric suction force generated by one shunt part 12, two shunt parts 12, and three shunt parts 12 on the moving contact 2 are calculated respectively.

[0044] When there is only one shunt section, the current flowing through the shunt section is 400A, and the generated electric suction force is as follows:

[0045] F L2 =(μ0 / 4π)*k*i 2 =(μ0 / 4π)*k*400 2 ;

[0046] When two shunts are connected in parallel, the current of each shunt is 200A, and the electric suction force F of one shunt is L2’ =(μ0 / 4π)*k*i 2 =(μ0 / 4π)*k*200 2 ;

[0047] Total electric suction force F of the two diversion parts L2 =2*F L2’ =2*(μ0 / 4π)*k*200 2 ;

[0048] When three shunts are connected in parallel, the current flowing through each shunt is about 133A, and the electric suction force F of one shunt is L2” =(μ0 / 4π)*k*i 2 =(μ0 / 4π)*k*133 2 ;

[0049] Total electric suction force F of the three diversion parts L2 =3*F L2” =3*(μ0 / 4π)*k*133 2 ;

[0050] The multiples of the electrodynamic repulsion in the three cases are:

[0051] (μ0 / 4π)*k*400 2 :2*(μ0 / 4π)*k*200 2 :3*(μ0 / 4π)*k*133 2

[0052] =160000:80000:53067.

[0053] In summary, the more diversion parts there are, the smaller the electric suction force is and the greater the short-term tolerance capacity is.

[0054] Preferably, the main body 11 includes at least two groups, and the at least two groups of main body 11 are connected in parallel. The at least two groups of main body 11 are arranged at intervals to form an escape space for the switching activities of the moving contact 2 and the contact part 13. Specifically, Figure 1 As shown, the two groups of main body parts 11 are arranged at intervals in front and back, with an escape space formed in the middle, the joint part 14 is arranged at the left end of the two groups of main body parts 11 and extends toward the left, and the contact part 13 is arranged at the right end of the two groups of main body parts 11 and also extends toward the left. That is to say, the two groups of main body parts 11 are connected in parallel and then connected in series with the contact part 13 and the joint part 14, and the contact part 13 is arranged between the two groups of main body parts 11, and swings up and down in the escape space to contact with the contact part 13 for conduction or separation.

[0055] Optionally, any group of main body parts 11 is provided with at least three shunt parts 12, at least three shunt parts 12 are arranged in parallel and spaced apart in the vertical direction, and two ends of each shunt part 12 are respectively connected to two connecting parts 111 of the main body part 11. Optionally, the resistance of at least one shunt part 12 among the at least three shunt parts 12 is different from the resistance of other shunt parts 12. Preferably, the resistance of all shunt parts 12 is the same. The structural design is simpler.

[0056] Preferably, the main body 11, the shunt part 12, the contact part 13 and the joint part 14 are integrally formed. Specifically, the main body 11, the two shunt parts 12 and the contact part 13 formed by the joint part 14 and the two connecting parts 111 are all formed by stamping and bending a conductor. The integrally formed structure is simple, the manufacturing cost is low, and the manufacturing is convenient.

[0057] Preferably, the contact part 13 is far away from the connecting part 111. Figure 1 The end connected to the connecting portion 111 on the right side is also as shown Figure 1 The right end of the contact part 13 shown is formed with a bent portion 131 bent toward the shunt portion 12. The setting of the bent portion 131 can help the arc to move upward quickly and reduce the ablation of the contact. Specifically, the upper surface of the bent portion 131 is lower than the upper surface of the static contact. Optionally, all the shunt portions 12 are arranged in parallel and perpendicular to the connecting portion 111. Optionally, the joint portion 14 is in an inverted L shape.

[0058] Example 2

[0059] The contact system of this embodiment, such as Figure 1 to Figure 2 As shown, it includes a moving contact assembly and a static contact assembly that can be contacted and conducted, and the static contact assembly includes at least one static contact structure 1 of embodiment 1. The moving contact assembly can be linked with an operating mechanism (not shown). The specific structure of the moving contact assembly is not described and limited in detail here, and it is an existing conventional single-contact moving contact structure. For the moving contact assembly, it can include only one moving contact, or it can include multiple moving contacts, and the multiple moving contacts are connected by a linkage mechanism. As for the number of static contact assemblies, it can be one or more, corresponding to the number of moving contacts. Since the above-mentioned static contact structure is adopted, it also has at least the advantages of the static contact structure of the above-mentioned embodiment 1, which will not be repeated here.

[0060] Example 3

[0061] The circuit breaker of this embodiment, such as Figure 1 to Figure 2 As shown, it includes the contact system in embodiment 2. Since the above-mentioned stationary contact structure is adopted, it also has at least the advantages of the stationary contact structure in embodiment 1, which will not be described one by one here.

[0062] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A stationary contact structure, characterized in that: include: A main body (10) comprising a flow dividing portion (12) and at least two groups of main body portions (11), wherein each group of the main body portions (11) comprises two connecting portions (111) that are opposite to each other and spaced apart from each other, and the flow dividing portion (12) is arranged side by side between the two connecting portions (111) and is respectively connected to the two connecting portions (111); A contact portion (13) connected to the connecting portion (111) of the main body (11) close to the moving contact (2) and capable of contacting and conducting with the moving contact (2) to form a conductive circuit; When current flows through the conductive loop, the direction of the current flowing through all the shunt parts (12) and the moving contact (2) is the same and opposite to the direction of the current flowing through the contact part (13); Any group of the main body parts (11) is provided with at least three diverter parts (12), and the resistance of at least one diverter part (12) among the at least three diverter parts (12) is different from the resistance of the other diverter parts (12); The moving contact (2) is subjected to an electric force F L is equal to the electromotive repulsive force F of the contact part (13) on the moving contact (2) L1 The electric suction force F of all the diverter parts (12) on the moving contact (2) L2i the sum of F L =F L1 +F L21 +F L22 +…+F L2i ; wherein i is the number of the diversion parts (12); The flow dividing portion (12) is connected in parallel and in series with the main body portion (11); At least two groups of the main body parts (11) are connected in parallel; At least two groups of the main body parts (11) are arranged at intervals to form an escape space for the switching activities of the moving contact (2) and the contact part (13); An end of the contact portion (13) away from the connection portion (111) is formed with a bent portion (131) bent in a direction toward the diverter portion (12); All the flow dividing portions (12) are arranged in parallel and perpendicular to the connecting portion (111); a connector portion (14) arranged on the connecting portion (111) at one end of the main body portion (11) away from the moving contact (2), and extending in the same direction as the contact portion (13), both extending in a direction away from the moving contact (2); The direction of the current flowing through the joint portion (14) is the same as the direction of the current flowing through the shunt portion (12) and the moving contact (2), and is opposite to the direction of the current flowing through the contact portion (13).

2. The stationary contact structure according to claim 1, characterized in that: The main body portion (11), the diverter portion (12), the contact portion (13) and the joint portion (14) are integrally formed.

3. A contact system, comprising a static contact and a moving contact capable of contacting and conducting, characterized in that: The stationary contact comprises the stationary contact structure according to any one of claims 1 to 2.

4. A circuit breaker, characterized in that: Comprising the contact system as claimed in claim 3.

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