An automatic circuit breaker for protecting against current overload

Abstract

The application provides a current overload automatic circuit breaker, belonging to the technical field of circuit protection. The current overload automatic circuit breaker comprises a shell, a moving contact, a static contact, an arc extinguishing chamber, a lock catch mechanism, a first wiring end, a second wiring end and a circuit protection mechanism. The shell is internally provided with an overload protection mechanism. The overload protection mechanism comprises an adjusting assembly. Two symmetrical bimetallic strips are arranged on the adjusting assembly. The adjusting assembly comprises a conductive rod. Symmetrical heat dissipation assemblies are arranged at the two ends of the conductive rod. The heat dissipation assemblies comprise adjusting bins fixedly connected with the outer wall of the conductive rod. An adapter assembly is slidably connected with the outer wall of the conductive rod between the two adjusting bins. When the circuit breaker is running in the state close to the rated current, the gas in the gas storage cavity can enter the inside of the corresponding adjusting bin through the one-way valve and the throttle pipe, circulate, reduce the temperature of the bimetallic strip, prevent unexpected tripping and improve the use effect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of automatic circuit breaking protection, and particularly relates to an automatic circuit breaking protection device for current overload. BACKGROUND

[0002] A circuit breaker is an automatic protective electrical switch, and its core function is to monitor the overload and short circuit of an electric circuit and automatically cut off the current when danger occurs to protect the electric wire, electrical equipment and human safety. When an overload occurs, the circuit breaker is tripped by the thermal bending of a bimetallic strip, and when a short circuit occurs, the circuit breaker is tripped by the electromagnetic principle. The circuit breaker is an essential safety device in modern power systems.

[0003] A large-current circuit breaker is disclosed in Chinese Patent No. CN202110339651.3, which comprises a housing, a moving contact, a static contact, an arc extinguishing chamber and a lock catch installed in the housing. The lock catch is above the position where the moving contact and the static contact cooperate. The static contact is provided with an arc guide part. An arc guide plate is also installed in the housing, and the arc guide plate and the arc guide part form an arc guide channel. The bottom of the lock catch is provided with a thickened part extending towards the position where the moving contact and the static contact cooperate. When the lock catch moves the moving contact and the static contact, the thickened part of the lock catch moves above the position where the moving contact and the static contact cooperate, forming a downward airflow to blow the arc generated by the disconnection between the moving contact and the static contact to move downward faster. The invention can solve the problem of poor arc guidance caused by an increase in current, thereby achieving fast arc extinguishing. It can also solve the problem of serious temperature rise at the contact caused by a large current and ensure the stability of the parameters of the circuit breaker. In addition, it can improve the breaking capacity and electrical life of the circuit breaker.

[0004] However, when the circuit breaker is continuously operated for a long time in a state close to its rated current (e.g., 90%-100% of the rated value), even if the load current does not exceed the rated value instantaneously, the built-in thermal tripping bimetallic strip will slowly heat up due to the joule heat generated by continuous power supply. This continuous heat accumulation will cause the bimetallic strip to gradually deform and displace. If the heat accumulation reaches a critical point, the tripping mechanism will eventually be triggered, causing the circuit breaker to trip unexpectedly. If the circuit breaker is operated again in a state close to its rated current shortly after tripping, the bimetallic strip will still have a considerable amount of residual heat because it has not cooled down to its initial state. When the bimetallic strip is subjected to current again, its temperature will rise faster to the tripping threshold, causing the tripping temperature to be reached faster in the subsequent process, resulting in premature tripping and a vicious cycle. This will cause the circuit breaker to frequently malfunction even if the effective value or average value of the actual load current does not exceed its continuous operating capacity, seriously affecting the normal operation period and production efficiency of the equipment.

[0005] Therefore, in order to solve the above problems, an automatic circuit breaking protection device for current overload is needed. SUMMARY

[0006] The present application aims to provide a current overload automatic circuit breaker, which aims to solve the problem in the prior art that when the circuit breaker is continuously operated for a long time in a state close to its rated current, the built-in thermal trip bimetallic strip will be continuously powered, slowly heated, and eventually tripped, causing the circuit breaker to be unexpectedly tripped, and if the circuit breaker is operated again in a state close to its rated current in a short time after being closed, the residual heat of the bimetallic strip will rise to the tripping threshold more quickly, causing the circuit breaker to trip in advance, resulting in a vicious cycle, which can cause the circuit breaker to frequently malfunction when the effective value or average value of the actual load current does not exceed its continuous operation capacity, seriously affecting the normal operation period and production efficiency of the equipment.

[0007] To achieve the above object, the present application provides the following technical scheme:

[0008] A current overload automatic circuit breaker, comprising a housing, a moving contact, a stationary contact, an arc extinguishing chamber, a lock catch mechanism, a first wiring end, a second wiring end and a circuit protection mechanism.

[0009] The inside of the housing is provided with an overload protection mechanism, and the overload protection mechanism comprises an adjusting assembly, two symmetrical bimetallic strips are arranged on the adjusting assembly, the adjusting assembly comprises a conductive rod, and heat dissipation assemblies are symmetrically arranged at both ends of the conductive rod. The heat dissipation assemblies comprise adjusting bins fixedly connected with the outer wall of the conductive rod, and a switching assembly is slidably connected with the outer wall of the conductive rod between the two adjusting bins. By moving the position of the switching assembly, the line switching of the two bimetallic strips can be performed.

[0010] Preferably, the inside of each adjusting bin is slidably connected with a piston plate slidably connected with the outer wall of the conductive rod, a first elastic member is connected between the side of each piston plate close to each other and the inner wall of the corresponding adjusting bin, the side of each piston plate away from each other can form an accommodating cavity with the inner wall of the corresponding adjusting bin, two guide tubes in communication with the corresponding accommodating cavity are fixedly connected to the side of each piston plate close to each other, and the first elastic member is slidably sleeved on the outer wall of the conductive rod.

[0011] Preferably, the inside of each guide tube is provided with a throttle pipe and a one-way valve, the outer wall of the end of each guide tube away from the piston plate is provided with a flow guide hole, the outer wall of the end of each guide tube away from the piston plate is fixedly connected with a limiting plate, the side of each limiting plate away from the adjusting bin is provided with a blocking ring slidably connected with the outer wall of the corresponding guide tube, a second elastic member is connected between each blocking ring and the corresponding limiting plate, and each second elastic member is slidably sleeved on the outer wall of the corresponding guide tube.

[0012] Preferably, the outer wall of the conductive rod between the two adjusting bins is provided with two symmetrically arranged guide grooves, the adapter assembly comprises a connecting ring, the inner side of the connecting ring is fixedly connected with sliding blocks in a number same as and opposite to the guide grooves, each sliding block is in sliding connection with the inner wall of the corresponding guide groove, the inside of the connecting ring is provided with a gas storage cavity, the top and bottom of the connecting ring are provided with two isolation pipes, each isolation pipe is provided with a sealing plate on one side in the gas storage cavity, each sealing plate is connected with the inner wall of the gas storage cavity through a third elastic piece, and each third elastic piece is in sliding sleeve connection with the outer wall of the corresponding isolation pipe.

[0013] Preferably, the outer wall of the connecting ring is fixedly connected with an elastic ring, the outer wall of the elastic ring is fixedly connected with two symmetrically arranged extrusion pieces, and the two extrusion pieces can form a limiting groove.

[0014] Preferably, the two guide pipes at the top of the conductive rod are in one-to-one correspondence with the two isolation pipes at the top of the connecting ring, and the two guide pipes at the bottom of the conductive rod are in one-to-one correspondence with the two isolation pipes at the bottom of the connecting ring.

[0015] Preferably, the arc extinguishing chamber comprises an arc striking plate, one end of the arc striking plate is movably connected with an insulating plate, the bottom of the insulating plate is fixedly connected with a lead-through piece, and the inside of the gas storage cavity and the accommodating cavity is filled with thermal expansion gas.

[0016] Preferably, one end of each bimetallic strip is provided with a clamping piece fixedly connected with the inner wall of the shell, clamping grooves are formed in the two bimetallic strips, and the adjusting assembly is arranged in the two clamping grooves.

[0017] Preferably, the top of the bimetallic strip close to the lead-through piece is provided with an avoiding groove, the top of the bimetallic strip close to the lead-through piece is connected with the lead-through piece through a first elastic conductive piece, the top of the bimetallic strip away from the lead-through piece is connected with the lead-through piece through a second elastic conductive piece, and the second elastic conductive piece penetrates through the avoiding groove.

[0018] Preferably, the lock catch mechanism comprises a lever, two lever rods in sliding connection with the inner wall of the shell are arranged on the lever, and the two lever rods are respectively matched with one end of the two bimetallic strips away from the clamping piece.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] 1. The present application can make the temperature inside the gas storage cavity rise when the circuit breaker is running in the state close to its rated current, can make the gas inside the gas storage cavity expand, the gas expansion can make the pressure become larger, under the action of the pressure, can make the gas inside the gas storage cavity enter the inside of one of the corresponding guide pipes, and through the corresponding check valve and throttle pipe, realize cooling, and enter the inside of the corresponding adjusting bin, mix with the gas inside the adjusting bin, can make the pressure inside the adjusting bin become larger, can make the gas inside the adjusting bin push into the inside of another corresponding guide pipe, the gas can pass through the corresponding check valve and throttle pipe to further cool down, and return to the inside of the gas storage cavity, thereby the temperature of the connecting ring and the elastic ring can be reduced to reduce the temperature of the bimetallic strip, avoid the bimetallic strip triggering the action of the tripping mechanism due to heat accumulation, prevent unexpected tripping, and improve the use effect.

[0021] 2. The present application can make the temperature inside the gas storage cavity rise when the circuit breaker is running in the state close to its rated current, can make the gas inside the gas storage cavity expand, the gas expansion can make the pressure become larger, under the action of the pressure, can make the gas inside the gas storage cavity enter the inside of one of the corresponding guide pipes, and through the corresponding check valve and throttle pipe, realize cooling, and enter the inside of the corresponding adjusting bin, mix with the gas inside the adjusting bin, can make the pressure inside the adjusting bin become larger, can make the gas inside the adjusting bin push into the inside of another corresponding guide pipe, the gas can pass through the corresponding check valve and throttle pipe to further cool down, and return to the inside of the gas storage cavity, thereby the temperature of the connecting ring and the elastic ring can be reduced to reduce the temperature of the bimetallic strip, avoid the bimetallic strip triggering the action of the tripping mechanism due to heat accumulation, prevent unexpected tripping, and improve the use effect. BRIEF DESCRIPTION OF DRAWINGS

[0022] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, together with the embodiments of the present application, to explain the present application, and do not constitute a limitation on the present application. In the drawings:

[0023] Figure 1 It is the overall structure schematic diagram of the present application;

[0024] Figure 2 It is the internal structure schematic diagram of the shell of the present application;

[0025] Figure 3 It is the structure schematic diagram of the overload protection mechanism of the present application;

[0026] Figure 4 It is the structure schematic diagram of the adjusting assembly of the present application;

[0027] Figure 5It is a structure schematic view of the guide groove and the sliding block of the application;

[0028] Figure 6 It is a structure schematic view of the inside of the adjusting bin of the application;

[0029] Figure 7 It is a structure schematic view of the inside of the connecting ring of the application;

[0030] Figure 8 It is a structure schematic view of the guide pipe of the application;

[0031] Figure 9 It is a structure schematic view of the bimetallic strip of the application.

[0032] In the figure: 1, the shell; 11, the moving contact; 12, the static contact; 13, the arc extinguishing chamber; 14, the lock catch mechanism; 15, the first wiring end; 16, the second wiring end; 17, the circuit breaking protection mechanism; 18, the arc striking plate; 19, the insulating plate; 110, the guide connecting piece; 111, the lever; 112, the pushing rod; 2, the overload protection mechanism; 3, the adjusting assembly; 31, the conductive rod; 32, the guide groove; 4, the bimetallic strip; 41, the clamping piece; 42, the clamping groove; 43, the avoiding groove; 44, the first elastic conductive piece; 45, the second elastic conductive piece; 5, the heat dissipation assembly; 51, the adjusting bin; 52, the piston plate; 53, the first elastic piece; 54, the accommodating cavity; 55, the guide pipe; 56, the throttling pipe; 57, the one-way valve; 58, the flow guiding hole; 59, the limiting plate; 510, the plugging ring; 511, the second elastic piece; 6, the switching assembly; 61, the connecting ring; 62, the sliding block; 63, the gas storage cavity; 64, the isolation pipe; 65, the sealing plate; 66, the third elastic piece; 67, the elastic ring; 68, the extruding piece; 69, the limiting groove. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0034] Embodiment one

[0035] In use, when the circuit breaker is continuously operated for a long time in a state close to its rated current, even if the load current does not instantaneously exceed the rated value, the built-in thermal release bimetallic strip will slowly heat up due to the joule heat generated by the continuous power supply. This continuous heat accumulation will cause the bimetallic strip to gradually produce displacement, and if the heat accumulation reaches a critical point, the release mechanism will eventually be triggered to cause the circuit breaker to trip unexpectedly, affecting use.

[0036] Please refer to Figures 1 to 5 The application provides the following technical scheme: a current overload automatic circuit breaker, comprising a shell 1, a moving contact 11, a static contact 12, an arc extinguishing chamber 13, a locking mechanism 14, a first wiring end 15, a second wiring end 16 and a circuit protection mechanism 17.

[0037] The inside of the shell 1 is provided with an overload protection mechanism 2, and the overload protection mechanism 2 comprises an adjusting assembly 3, two bimetallic strips 4 are symmetrically arranged on the adjusting assembly 3, the adjusting assembly 3 comprises a conductive rod 31, heat dissipation assemblies 5 are symmetrically arranged at both ends of the conductive rod 31, the heat dissipation assemblies 5 comprise adjusting bins 51 fixedly connected with the outer wall of the conductive rod 31, and the outer wall of the conductive rod 31 is slidably connected with switching assemblies 6 between the two adjusting bins 51; by moving the position of the switching assemblies 6, the line switching of the two bimetallic strips 4 can be realized.

[0038] The moving contact 11, the static contact 12, the arc extinguishing chamber 13, the locking mechanism 14, the first wiring end 15, the second wiring end 16 and the circuit protection mechanism 17 are all prior art, and will not be repeated here.

[0039] The bottom of the conductive rod 31 can be electrically connected with the second wiring end 16, and the adjusting bin 51 is fixedly connected with the inner wall of the shell 1.

[0040] As shown in Figure 6 each adjusting bin 51 is slidably connected with a piston plate 52 slidably connected with the outer wall of the conductive rod 31, a first elastic member 53 is connected between the side, where the two piston plates 52 are close to each other, and the inner wall of the corresponding adjusting bin 51, a containing cavity 54 can be formed between the side, where the two piston plates 52 are away from each other, and the inner wall of the corresponding adjusting bin 51, two guide pipes 55, which are in communication with the corresponding containing cavity 54, are fixedly connected to the side, where the two piston plates 52 are close to each other, one end of each guide pipe 55 away from the piston plate 52 penetrates through the corresponding adjusting bin 51, and the first elastic member 53 is slidably sleeved on the outer wall of the conductive rod 31.

[0041] As shown in Figure 8 each guide pipe 55 is provided with a throttle pipe 56 and a one-way valve 57 in the inside, a flow guide hole 58 is formed in the outer wall of one end of each guide pipe 55 away from the piston plate 52, a limiting plate 59 is fixedly connected to the outer wall of one end of each guide pipe 55 away from the piston plate 52, a blocking ring 510 slidably connected with the outer wall of the corresponding guide pipe 55 is arranged on the side of each limiting plate 59 away from the adjusting bin 51, a second elastic member 511 is connected between each blocking ring 510 and the corresponding limiting plate 59, and each second elastic member 511 is slidably sleeved on the outer wall of the corresponding guide pipe 55.

[0042] The inner diameter of the throttle pipe 56 is smaller than the inner diameter of the guide pipe 55. When the gas passes through the throttle pipe 56, the flow rate will increase, the pressure will decrease, and the temperature will drop significantly. The gas in each adjusting bin 51 can enter the inside of a corresponding guide pipe 55 and pass through the corresponding one-way valve 57 to enter the inside of the gas storage cavity 63. When the gas in the gas storage cavity 63 enters the inside of another corresponding guide pipe 55, the gas can pass through the corresponding one-way valve 57 to enter the inside of the adjusting bin 51. The gas flow directions of the two one-way valves 57 on the same adjusting bin 51 are opposite.

[0043] In a normal state, i.e., when the blocking ring 510 is not in contact with the connecting ring 61, the blocking ring 510 can block the corresponding flow guide hole 58.

[0044] As shown in Figure 7 The outer wall of the connecting ring 61 is fixedly connected with an elastic ring 67. The outer wall of the elastic ring 67 is fixedly connected with two symmetrically arranged extrusion pieces 68. The two extrusion pieces 68 can form a limiting groove 69 therebetween.

[0045] When the adapter assembly 6 moves towards the inside of the clamping groove 42 of the bimetallic strip 4, the extrusion pieces 68 can be extruded and contacted by the inner wall of the clamping groove 42, so that the elastic ring 67 is deformed towards the connecting ring 61. Then, when the inner wall of the clamping groove 42 is located in the middle of the limiting groove 69, the elastic ring 67 can be elastically reset, and the adapter assembly 6 can be limited and fixed by the two extrusion pieces 68.

[0046] In an initial state, the adapter assembly 6 is located in the clamping groove 42 of the bimetallic strip 4 near the top of the conductive rod 31. At this time, the inner wall of the clamping groove 42 is located in the middle of the limiting groove 69 and can be limited by the two extrusion pieces 68. When the conductive rod 31 is electrified, the current can enter the corresponding bimetallic strip 4 through the connecting ring 61 and the elastic ring 67, and be communicated with the lead-through piece 110 through the first elastic conductive piece 44. When the adapter assembly 6 is located in the clamping groove 42 of the bimetallic strip 4 near the bottom of the conductive rod 31, at this time, the inner wall of the clamping groove 42 is located in the middle of the limiting groove 69 and can be limited by the two extrusion pieces 68. When the conductive rod 31 is electrified, the current can enter the corresponding bimetallic strip 4 through the connecting ring 61 and the elastic ring 67, and be communicated with the lead-through piece 110 through the second elastic conductive piece 45.

[0047] As shown in Figure 4 The two guide pipes 55 at the top of the conductive rod 31 are one-to-one correspondingly arranged with the two isolation pipes 64 at the top of the connecting ring 61. The two guide pipes 55 at the bottom of the conductive rod 31 are one-to-one correspondingly arranged with the two isolation pipes 64 at the bottom of the connecting ring 61.

[0048] When the adapter assembly 6 is located in the clamping groove 42 of the bimetallic strip 4 near the top of the conductive rod 31, the corresponding two guide tubes 55 can be inserted into the two isolation tubes 64 at the top of the connecting ring 61, at this time the corresponding blocking ring 510 can be extruded by the top of the connecting ring 61, the second elastic element 511 is compressed, the blocking ring 510 can move towards the opposite direction close to the limiting plate 59, which can expose the flow guide hole 58, at the same time, during the insertion of the guide tube 55 into the connecting ring 61, the bottom of the corresponding guide tube 55 can extrude the sealing plate 65, which can move the sealing plate 65 away from the isolation tube 64, which can make the corresponding flow guide hole 58 communicate with the inside of the gas storage cavity 63.

[0049] When the adapter assembly 6 is located in the clamping groove 42 of the bimetallic strip 4 near the bottom of the conductive rod 31, the corresponding two guide tubes 55 can be inserted into the two isolation tubes 64 at the bottom of the connecting ring 61, at this time the corresponding blocking ring 510 can be extruded by the bottom of the connecting ring 61, the second elastic element 511 is compressed, the blocking ring 510 can move towards the opposite direction close to the limiting plate 59, which can expose the flow guide hole 58, at the same time, during the insertion of the guide tube 55 into the connecting ring 61, the top of the corresponding guide tube 55 can extrude the sealing plate 65, which can move the sealing plate 65 away from the isolation tube 64, which can stretch the third elastic element 66, which can make the corresponding flow guide hole 58 communicate with the inside of the gas storage cavity 63.

[0050] The arc extinguishing chamber 13 includes an arc striking plate 18, one end of the arc striking plate 18 movably connected with an insulating plate 19, the bottom of the insulating plate 19 fixedly connected with a lead 110, the inside of the gas storage cavity 63 and the accommodating cavity 54 are filled with thermal expansion gas.

[0051] When the moving contact 11 is separated from the static contact 12 to generate an arc, the arc can be guided into the arc extinguishing chamber 13 for arc extinguishing, the arc striking plate 18 is a prior art, which will not be described here.

[0052] The locking mechanism 14 includes a lever 111, the lever 111 is provided with two sliding rods 112 which are slidingly connected with the inner wall of the shell 1, the two sliding rods 112 are respectively matched with the end of the two bimetallic strips 4 away from the clamping piece 41.

[0053] When the switch of the locking mechanism 14 is operated, i.e. the gate is closed, the lever 111 can slide on the locking mechanism 14, in this process, through the tension of the first elastic conductive element 44 or the second elastic conductive element 45, the insulating plate 19 can be rotated, the top of the lead 110 can always be in contact with the bottom of the moving contact 11, the prior art will not be described here, when the moving contact 11 is in contact with the static contact 12 to be electrified, the locking mechanism 14 is locked and limited, the two sliding rods 112 are respectively at the bottom of the two bimetallic strips 4, like Figure 3As shown, when the bimetallic strip 4 is deformed by heat, it can deform and bend downward, push the corresponding push rod 112 downward, and separate the movable contact 11 from the static contact 12 to achieve power-off closing.

[0054] It should be noted that in use, the adapter assembly 6 is located inside the clamping groove 42 on the bimetallic strip 4, at this time, the corresponding two guide pipes 55 can be inserted one by one into the inside of the corresponding isolation pipe 64, the blocking ring 510 can be extruded by the top of the connecting ring 61, and can move in the opposite direction close to the limiting plate 59, so that the flow guide hole 58 is exposed, and in the process of inserting the guide pipe 55 into the connecting ring 61, the sealing plate 65 of the corresponding guide pipe 55 can be extruded, and the sealing plate 65 can be moved away from the isolation pipe 64, so that the corresponding flow guide hole 58 is connected with the inside of the gas storage cavity 63, and the lock catch mechanism 14 is operated to close the gate, when the movable contact 11 and the static contact 12 are in contact and powered on, the lock catch mechanism 14 is locked and limited, and the two push rods 112 are respectively at the bottom of the two bimetallic strips 4. Because the current can pass through the connecting ring 61 and the elastic ring 67 into the corresponding bimetallic strip 4 when the conductive rod 31 is powered on, at this time the circuit breaker is running in the state close to its rated current, the temperature inside the gas storage cavity 63 can be raised, and the gas inside the gas storage cavity 63 can be expanded, the gas expansion can increase the pressure, under the action of the pressure, the gas inside the gas storage cavity 63 can enter the inside of one of the corresponding guide pipes 55, and pass through the corresponding one-way valve 57 and the throttle pipe 56 to realize cooling, and enter the inside of the adjusting bin 51, and mix with the gas inside the adjusting bin 51, so that the pressure inside the adjusting bin 51 can be increased, and the gas inside the adjusting bin 51 can be pushed into the inside of the other corresponding guide pipe 55, and the gas can be further cooled through the corresponding one-way valve 57 and the throttle pipe 56, and returned to the inside of the gas storage cavity 63, forming a cycle, thereby the temperature of the adjusting bin 51, the elastic ring 67 and the connecting ring 61 can be reduced by reducing the temperature, the heat of the bimetallic strip 4 can be absorbed, the temperature of the bimetallic strip 4 can be reduced by heat transfer, the bimetallic strip 4 can be prevented from triggering the trip mechanism due to heat accumulation, unintended tripping can be prevented, and the use effect can be improved.

[0055] In summary, the application is provided with the heat dissipation assembly 5, when the circuit breaker is operated in the state close to the rated current, the temperature inside the gas storage cavity 63 is increased, the gas inside the gas storage cavity 63 is expanded, the pressure is increased, under the action of the pressure, the gas inside the gas storage cavity 63 enters the inside of one corresponding guide pipe 55, and the temperature is lowered through the corresponding one-way valve 57 and the throttle pipe 56, and the gas enters the inside of the corresponding adjusting bin 51 and mixes with the gas inside the adjusting bin 51, so that the pressure inside the adjusting bin 51 is increased, the gas inside the adjusting bin 51 enters the inside of another corresponding guide pipe 55, the gas is further cooled through the corresponding one-way valve 57 and the throttle pipe 56, and returns to the inside of the gas storage cavity 63, thereby the temperature of the bimetallic strip 4 is lowered by lowering the temperature of the connecting ring 61 and the elastic ring 67, the action of the tripping mechanism triggered by the heat accumulation of the bimetallic strip 4 is avoided, the unintended tripping is prevented, and the use effect is improved.

[0056] Embodiment two

[0057] On the basis of the above embodiment, if the circuit breaker is operated again in the state close to the rated current in a short time after the closing, since the bimetallic strip cannot be fully cooled to the initial state, a considerable amount of heat is still left, and the temperature of the bimetallic strip is more quickly increased to the tripping threshold on the basis of the left heat, so that the phenomenon of the subsequent tripping temperature being reached more quickly is caused, the tripping is advanced, a vicious cycle is caused, and the circuit breaker is frequently misoperated in the case that the effective value or the average value of the actual load current does not exceed the continuous operation capacity, so that the normal operation period and the production efficiency of the equipment are seriously affected.

[0058] Please refer to Figures 4 to 9 The outer wall of the conductive rod 31 located between the two adjusting bins 51 is provided with two symmetrically arranged guide grooves 32, the transfer assembly 6 comprises a connecting ring 61, the inner side of the connecting ring 61 is fixedly connected with sliding blocks 62 which are the same in number as the guide grooves 32 and are opposite in position, each sliding block 62 is in sliding connection with the inner wall of the corresponding guide groove 32, the inside of the connecting ring 61 is provided with a gas storage cavity 63, the top and the bottom of the connecting ring 61 are provided with two isolation pipes 64, each isolation pipe 64 located on one side of the inside of the gas storage cavity 63 is provided with a sealing plate 65, each sealing plate 65 is connected with the inner wall of the gas storage cavity 63 through a third elastic element 66, and each third elastic element 66 is slidingly sleeved on the outer wall of the corresponding isolation pipe 64.

[0059] In the normal state, the guide pipe 55 is not in contact with the sealing plate 65, and the sealing plate 65 can block the corresponding isolation pipe 64.

[0060] As Figure 2 , Figure 3 and Figure 9As shown, one end of each bimetallic strip 4 is provided with a clamping piece 41 fixedly connected with the inner wall of the shell 1, and a clamping groove 42 is formed in each bimetallic strip 4, and the adjusting assembly 3 is arranged in the two clamping grooves 42.

[0061] As shown, the top of the bimetallic strip 4 close to the lead-through 110 is provided with an avoiding groove 43, the top of the bimetallic strip 4 close to the lead-through 110 is connected with the lead-through 110 through a first elastic conductive piece 44, and the top of the bimetallic strip 4 away from the lead-through 110 is connected with the lead-through 110 through a second elastic conductive piece 45, and the second elastic conductive piece 45 passes through the avoiding groove 43. Figure 9

[0062] The purpose of arranging the avoiding groove 43 is to avoid the influence of the energization of the second elastic conductive piece 45 on the bimetallic strip 4 close to the lead-through 110.

[0063] It should be noted that when the circuit breaker is operated in a state exceeding the rated current, the increased current can increase the temperature inside the gas storage cavity 63, the gas inside the gas storage cavity 63 can expand, the pressure can increase, the gas inside the gas storage cavity 63 can enter the inside of one of the corresponding guide pipes 55, pass through the corresponding one-way valve 57 and the throttle pipe 56, and enter the inside of the adjusting bin 51, the pressure inside the adjusting bin 51 can increase, the gas inside the adjusting bin 51 can enter the inside of the other corresponding guide pipe 55, pass through the corresponding one-way valve 57 and the throttle pipe 56, and return to the inside of the gas storage cavity 63. In this process, although the throttle pipe 56 can cool the gas, due to the large increase in the overload current at this time, the heat generation will increase sharply, and the temperature inside the adjusting bin 51 and the gas storage cavity 63 will increase sharply, the throttle pipe 56 will not be able to meet the cooling demand, and the gas inside the adjusting bin 51 and the gas storage cavity 63 will be heated and expanded, the pressure inside the adjusting bin 51 will increase sharply, the piston plate 52 can be pushed to move towards the connecting ring 61, the first elastic piece 53 can be squeezed, the connecting ring 61 can be pushed to move towards the other bimetallic strip 4 through the blocking ring 510, the connecting ring 61 and the elastic ring 67 can enter the clamping groove 42 of the other bimetallic strip 4, and the switching of the bimetallic strip 4 can be realized. At the same time, when the temperature inside the adjusting bin 51 and the gas storage cavity 63 increases sharply, heat will also be transferred to the corresponding bimetallic strip 4, the bimetallic strip 4 can be deformed by heat, can be bent downward, can push the corresponding push rod 112 to move downward, can separate the moving contact 11 from the stationary contact 12, and realize power-off closing. Thus, by changing the line of the bimetallic strip 4 each time the overload occurs, the phenomenon that the bimetallic strip 4 cannot be fully cooled can be avoided, the residual heat of the bimetallic strip 4 can be prevented from causing premature tripping, and the normal operation period and production efficiency of the equipment can be avoided from being affected.

[0064] ​In summary, by setting two bimetallic sheets 4, when the circuit breaker is operated in a state exceeding its rated current, the current increases, which can sharply increase the heat generation, and can sharply increase the temperature inside the adjusting bin 51 and the gas storage cavity 63, the throttle pipe 56 cannot meet the cooling demand, which causes the gas inside the adjusting bin 51 and the gas storage cavity 63 to be heated and expanded, so that the pressure inside the adjusting bin 51 sharply increases, which can drive the piston plate 52 to move towards the connecting ring 61, can extrude the first elastic member 53, can drive the connecting ring 61 to move towards the other bimetallic sheet 4 through the blocking ring 510, can make the connecting ring 61 and the elastic ring 67 enter the clamping groove 42 of the other bimetallic sheet 4, can realize the switching of the bimetallic sheet 4 line, at the same time, the heat can also be transferred to the corresponding bimetallic sheet 4, which can make the bimetallic sheet 4 be deformed by heat, can make the moving contact 11 and the static contact 12 be separated, realize power-off closing, thereby, by replacing the bimetallic sheet 4 line each time, the phenomenon that the bimetallic sheet 4 cannot be fully cooled can be avoided, the residual heat of the bimetallic sheet 4 can be prevented from causing early tripping, and the normal power supply can be avoided from being affected.

[0065] Finally, it should be noted that: the above only describes the preferred embodiments of the present application and is not used to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, for those skilled in the art, the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A current overload automatic circuit breaker comprising a housing (1), a moving contact (11), a stationary contact (12), an arc extinguishing chamber (13), a locking mechanism (14), a first terminal (15), a second terminal (16) and a circuit protection mechanism (17), characterized in that: the interior of the housing (1) is provided with an overload protection mechanism (2), the overload protection mechanism (2) comprises an adjusting assembly (3), the adjusting assembly (3) is provided with two symmetrical bimetallic strips (4), the adjusting assembly (3) comprises a conductive rod (31), the two ends of the conductive rod (31) are provided with heat dissipation assemblies (5) in a symmetrical manner, the heat dissipation assemblies (5) comprise adjusting bins (51) fixedly connected with the outer wall of the conductive rod (31), the outer wall of the conductive rod (31) between the two adjusting bins (51) is slidably connected with an adapter assembly (6), by moving the position of the adapter assembly (6), the line switching of the two bimetallic strips (4) can be performed; the interior of each adjusting bin (51) is slidably connected with a piston plate (52) slidably connected with the outer wall of the conductive rod (31), the first elastic member (53) is connected between the side of the two piston plates (52) close to each other and the inner wall of the corresponding adjusting bin (51), the side of the two piston plates (52) away from each other can form an accommodating cavity (54) with the inner wall of the corresponding adjusting bin (51), the side of the two piston plates (52) close to each other is fixedly connected with two guide pipes (55) in communication with the corresponding accommodating cavities (54), one end of each guide pipe (55) away from the piston plate (52) penetrates through the corresponding adjusting bin (51), and the first elastic member (53) is slidably sleeved on the outer wall of the conductive rod (31); the interior of each guide pipe (55) is provided with a throttling pipe (56) and a one-way valve (57), the outer wall of one end of each guide pipe (55) away from the piston plate (52) is provided with a flow guide hole (58), the outer wall of one end of each guide pipe (55) away from the piston plate (52) is fixedly connected with a limiting plate (59), one side of each limiting plate (59) away from the adjusting bin (51) is provided with a blocking ring (510) slidably connected with the outer wall of the corresponding guide pipe (55), each blocking ring (510) and the corresponding limiting plate (59) are connected with a second elastic member (511), and each second elastic member (511) is slidably sleeved on the outer wall of the corresponding guide pipe (55). The outer wall of the conductive rod (31) located between the two adjusting bins (51) is provided with two symmetrically arranged guide grooves (32), the adapter assembly (6) comprises a connecting ring (61), the inner side of the connecting ring (61) is fixedly connected with sliding blocks (62) which are the same in number as the guide grooves (32) and are opposite in position, each sliding block (62) is in sliding connection with the inner wall of the corresponding guide groove (32), a gas storage cavity (63) is formed in the connecting ring (61), the top and bottom of the connecting ring (61) are each provided with two isolation pipes (64), each isolation pipe (64) located on one side in the gas storage cavity (63) is provided with a sealing plate (65), each sealing plate (65) and the inner wall of the gas storage cavity (63) are connected with a third elastic element (66), and each third elastic element (66) is in sliding sleeve connection with the outer wall of the corresponding isolation pipe (64).

2. The automatic circuit overload protector of claim 1, wherein: The outer wall of the connecting ring (61) is fixedly connected with an elastic ring (67), the outer wall of the elastic ring (67) is fixedly connected with two symmetrically arranged extrusion pieces (68), and the two extrusion pieces (68) can form a limiting groove (69) therebetween.

3. The automatic circuit overload protector of claim 2, wherein: The two guide pipes (55) at the top of the conductive rod (31) are arranged in one-to-one correspondence with the two isolation pipes (64) at the top of the connecting ring (61), and the two guide pipes (55) at the bottom of the conductive rod (31) are arranged in one-to-one correspondence with the two isolation pipes (64) at the bottom of the connecting ring (61).

4. The automatic circuit overload protector of claim 3, wherein: The arc-extinguishing chamber (13) comprises an arc striking plate (18), one end of the arc striking plate (18) is movably connected with an insulating plate (19), the bottom of the insulating plate (19) is fixedly connected with a lead-through piece (110), and the gas storage cavity (63) and the accommodating cavity (54) are filled with thermal expansion gas.

5. The automatic circuit overload protector of claim 4, wherein: One end of each bimetallic strip (4) is provided with a clamping piece (41) fixedly connected with the inner wall of the shell (1), and clamping grooves (42) are formed in the two bimetallic strips (4).

6. The automatic circuit overload protector of claim 5, wherein: An avoiding groove (43) is formed in the top of the bimetallic strip (4) close to the lead-through piece (110), a first elastic conductive piece (44) is connected between the top of the bimetallic strip (4) close to the lead-through piece (110) and the lead-through piece (110), a second elastic conductive piece (45) is connected between the top of the bimetallic strip (4) away from the lead-through piece (110) and the lead-through piece (110), and the second elastic conductive piece (45) passes through the avoiding groove (43).

7. The automatic circuit overload protector of claim 6, wherein: The lock catch mechanism (14) comprises a lever (111), two lever rods (112) are arranged on the lever (111) and are in sliding connection with the inner wall of the shell (1), and the two lever rods (112) are respectively matched with one end of the two bimetallic strips (4) away from the clamping piece (41).

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