A miniature circuit breaker

Abstract

The present application discloses a miniature circuit breaker, which includes an operating mechanism, a moving contact, a static contact and a conductive sheet. The operating mechanism includes a contact support and a locking structure; the locking structure includes a lock catch rotatably arranged on the contact support and a pull rod assembly; wherein, a shape memory alloy is further included. One end of the shape memory alloy abuts against the contact support, and the other end abuts against the lock catch; the shape memory alloy has an initial form and a transformed form; after an overload occurs in the main circuit, when the internal temperature of the miniature circuit breaker rises to the phase transition temperature of the shape memory alloy, the shape memory alloy changes from the initial form to the transformed form, and pushes the lock catch to rotate to unlock it from the pull rod assembly, prompting the operating mechanism to trip; the present application has a novel overload tripping structure.

Description

Technical Field

[0001] This application relates to the field of low-voltage electrical appliances, and specifically to a miniature circuit breaker. Background Art

[0002] A miniature circuit breaker can achieve overload protection and short-circuit protection. Existing miniature circuit breakers rely on a bimetal strip to achieve overload protection. The specific structure is that one end of the bimetal strip is welded to the moving contact through a flexible connection, and the other end is welded to a conductive sheet integrated with the terminal board. When the main circuit is overloaded, the temperature on the bimetal strip continuously rises, the bimetal strip gradually bends, and finally the latch of the operating mechanism is pulled by the bimetal pull rod to achieve overload protection. For example, a miniature circuit breaker thermal tripping mechanism and a miniature circuit breaker having the same disclosed in CN208489161U adopt such a structure. This kind of overload protection has existed for decades or even hundreds of years, and it has some limitations.

[0003] Problem one, since the bimetal strip needs to be welded in the main circuit conductor, there are at least three welding points here, namely the welding point between the moving contact and the flexible connection, the welding point between the flexible connection and the bimetal strip, and the welding point between the bimetal strip and the conductive sheet. In some cases, the conductive sheet is also an independent part that needs to be welded to the terminal board (so there are even more welding points). As for the welding process, there is a possibility of poor welding. Therefore, the more welding points there are, the greater the possibility of poor welding. Poor welding will cause the contact resistance to increase, making the bimetal heat up more rapidly, and there may be a possibility of false tripping (tripping occurs when there is no overload but the temperature reaches the value at which the bimetal bends).

[0004] Problem two, the existing bimetal strip is fixed on the arc runner, which causes the arc runner to also need to be provided with a matching structure for its welding and installation, invisibly increasing the design difficulty of the arc runner and the waste of materials.

[0005] Third, the bimetal strip needs to drive the latch to move through the bimetal pull rod. Designing the bimetal pull rod also needs to consider the problem of space occupation inside the circuit breaker, which increases the design difficulty and reduces the available space inside the circuit breaker.

[0006] Therefore, how to design a new type of overload protection structure is a problem worthy of exploration for miniature circuit breakers. Summary of the Invention

[0007] In view of this, the purpose of this application is to overcome the deficiencies in the prior art and aims to provide a miniature circuit breaker.

[0008] The present application provides a miniature circuit breaker, which includes an operating mechanism, a moving contact, a static contact, and a conductive sheet. The operating mechanism includes a contact support and a locking structure. The locking structure includes a latch rotatably arranged on the contact support and a tie rod assembly. The tie rod assembly and the latch have an unlocked state and a locked state. The operating mechanism includes a closed state and a tripped state. When the operating mechanism is in the closed state, the tie rod assembly and the latch are in the locked state. When the operating mechanism is in the tripped state, the tie rod assembly and the latch are in the unlocked state. Among them, a shape memory alloy is further included. One end of the shape memory alloy abuts against the contact support, and the other end abuts against the latch. The shape memory alloy has an initial form and a transformed form. After an overload occurs in the main circuit and the internal temperature of the miniature circuit breaker rises to the phase transition temperature of the shape memory alloy, the shape memory alloy changes from the initial form to the transformed form, and pushes the latch to rotate to unlock it from the tie rod assembly, prompting the operating mechanism to trip.

[0009] In some embodiments of the present application, a receiving cavity is formed on the contact support. One side of the receiving cavity has a triggering opening, and the triggering opening is opened on the side of the mounting portion away from the static contact. There is a blocking wall at the triggering opening where the latch is located. The shape memory alloy is installed in the receiving cavity. One end of the shape memory alloy passes through the triggering opening and abuts against the blocking wall, and the other end abuts against the cavity wall of the receiving cavity. When the shape memory alloy changes from the initial form to the transformed form, the latch is rotated by pushing the blocking wall.

[0010] In some embodiments of the present application, the contact support includes a main body portion and a mounting portion. The mounting portion is arranged on the upper surface of the main body portion, and the receiving cavity is arranged in the mounting portion. The receiving cavity is also provided with a mounting opening, and the mounting opening is opened on the upper surface of the mounting portion. The shape memory alloy is loaded into the receiving cavity from the mounting portion.

[0011] In some embodiments of the present application, the mounting portion includes a first wall, a second wall, and a third wall. The first wall, the second wall, and the third wall together with the main body portion surround to form the receiving cavity. The first wall is the side of the mounting portion close to the static contact, and the triggering opening is opened on the side of the mounting portion away from the first wall. At least any one of the second wall, the third wall, and the main body portion is provided with a notch. The shape memory alloy is in the shape of a compression spring, and the notch is used to reduce the contact area between the shape memory alloy and the receiving cavity.

[0012] In some embodiments of the present application, the mounting portion includes a first wall, a second wall, and a third wall. The first wall, the second wall, and the third wall together form the receiving cavity. At least any one of the first wall, the second wall, and the third wall is provided with an anti - detachment protrusion. The shape memory alloy is in the shape of a compression spring, and the anti - detachment protrusion abuts against the shape memory alloy to prevent the shape memory alloy from detaching from the receiving cavity through the mounting opening.

[0013] In some embodiments of the present application, the latch has a body portion disposed on the upper surface of the contact support; a through hole is formed in the upper surface of the body portion, and the mounting portion penetrates at least partially into the through hole; the through hole has a first side wall and a second side wall disposed opposite to each other, and the blocking wall is the second side wall; there is a first avoidance gap between the first side wall and the mounting portion, and the size of the first avoidance gap when the shape memory alloy is in the initial form is larger than the size when the shape memory alloy is in the changed form.

[0014] In some embodiments of the present application, the upper surface of the body portion has an annular portion, and the hollow portion of the annular portion also belongs to a part of the through hole, and the mounting portion does not extend beyond the hollow portion of the annular portion.

[0015] In some embodiments of the present application, the moving contact is connected to the conductive sheet through a flexible connection, and the number of solder joints among the three is less than three.

[0016] In some embodiments of the present application, the operating mechanism further includes a handle, the pull rod assembly includes a pull rod and a buckle, one end of the pull rod is connected to the buckle, the buckle is rotatably disposed on the contact support, and the locking state and unlocking state of the pull rod assembly and the latch are realized by the buckle and the latch.

[0017] In some embodiments of the present application, the operating mechanism further includes a handle, the pull rod assembly includes a pull rod, and the contact support also serves as a part of the locking structure. A first groove wall is provided on the contact support, and a second groove wall is provided on the latch. One end of the pull rod is connected to the handle, and the other end of the pull rod extends into the fitting groove formed by the first groove wall and the second groove wall. By changing the relative angle between the latch and the contact support, the gap between the first groove wall and the second groove wall changes, thereby realizing the locking and unlocking of the pull rod.

[0018] In some embodiments of the present application, it further includes a circuit breaker housing, an arc extinguishing chamber, and a partition member; the circuit breaker housing has an arc extinguishing chamber and a first air passage and a second air passage located at the rear of the arc extinguishing chamber, and the first air passage and the second air passage communicate with the arc extinguishing chamber; the arc extinguishing chamber and the partition member are disposed in the arc extinguishing chamber, and the partition member is fixed to the rear end of the arc extinguishing chamber; the partition member includes a first partition rib and a second partition rib, and the first partition rib and the second partition rib intersect vertically and horizontally and divide the rear part of the arc extinguishing cover into a first upper region, a first lower region, a second upper region, and a second lower region; the first upper region and the second upper region are both communicated with the first air passage, and the second upper region and the second lower region are both communicated with the second air passage.

[0019] The beneficial effects of the present application compared with the prior art:

[0020] With the above structure, the technical prejudice that the thermal release must be welded to the main circuit conductor is overcome. The shape memory alloy directly senses the internal temperature of the circuit breaker. When it undergoes a phase change, its shape changes and acts on the latch to cause the operating mechanism to trip, achieving overload protection and replacing the traditional bending of the bimetallic strip to achieve overload protection. It has the following advantages: First, compared with the prior art, the number of solder joints on the main circuit conductor is reduced by at least one (because the shape memory alloy does not need to be welded to the main circuit conductor), so the probability of false soldering is reduced, ensuring the performance of the product. Second, since there is no bimetallic strip, the arcing path design of the circuit breaker will be simpler, without the need to additionally design the installation position of the bimetallic strip (the prior art must design the corresponding installation position), saving materials, simplifying the structure and the installation process. Third, since the shape memory alloy directly acts on the latch and the bracket, it does not need to rely on a bimetallic rod to drive the latch movement as in the prior art. Therefore, such a structure also reduces the components of the operating mechanism and simplifies the installation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0022] Figure 1 Shows a schematic diagram of the interior of a miniature circuit breaker according to an embodiment of the present application;

[0023] Figure 2 Shows a perspective view of a miniature circuit breaker according to an embodiment of the present application;

[0024] Figure 3 Shows a schematic diagram of another perspective of the interior of a miniature circuit breaker according to an embodiment of the present application;

[0025] Figure 4 Shows a schematic diagram of a miniature circuit breaker according to an embodiment of the present application in the closed state, with the shape memory alloy in its initial form;

[0026] Figure 5 Shows a schematic diagram of a miniature circuit breaker according to an embodiment of the present application in the open state, with the shape memory alloy in its changed form;

[0027] Figure 6 Shows a schematic diagram of the contact support and the latch in an embodiment of the present application;

[0028] Figure 7 Shows a schematic diagram of the latch and the contact support when the shape memory alloy is in its initial form in an embodiment of the present application;

[0029] Figure 8 Shows a schematic diagram of the latch and the contact support when the shape memory alloy is in a deformed state in an embodiment of the present application;

[0030] Figure 9 Shows a schematic diagram of the contact support in an embodiment of the present application;

[0031] Figure 10 Shows a schematic diagram of the latch in an embodiment of the present application;

[0032] Figure 11 Shows a schematic diagram of the shape memory alloy and the contact support in an embodiment of the present application;

[0033] Figure 12 Shows a three - dimensional view of the separator and the arc - extinguishing chamber in an embodiment of the present application;

[0034] Figure 13 Shows a rear view of the separator and the arc - extinguishing chamber in an embodiment of the present application;

[0035] Figure 14 Shows a three - dimensional view of the separator and the arc - extinguishing chamber from another perspective in an embodiment of the present application;

[0036] Figure 15 Shows a three - dimensional view of the separator in an embodiment of the present application;

[0037] Figure 16 Shows a three - dimensional view of the arc - extinguishing chamber in an embodiment of the present application;

[0038] Figure 17 Shows a cross - sectional view of the circuit breaker housing in an embodiment of the present application;

[0039] Figure 18 Shows a cross - sectional view of the first and second air passages of the new type of miniature circuit breaker in an embodiment of the present application. Detailed implementation manners

[0040] The embodiments of the present application will be described in detail below. The examples of the embodiments are shown in the drawings, in which the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions from beginning to end. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present application and should not be construed as a limitation of the present application.

[0041] In the description of the present application, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0042] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, the meaning of "a plurality of" is two or more unless otherwise specifically defined.

[0043] In the present application, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0044] In the present application, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature is at a higher horizontal height than the second feature. The first feature being "under", "beneath" and "under" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature is at a lower horizontal height than the second feature. Embodiment

[0045] As Figures 1 - 2 shown, an embodiment of the present application is a miniature circuit breaker.

[0046] The miniature circuit breaker includes a circuit breaker housing 300, moving and static contacts, an operating mechanism, an overload protection release, an instantaneous protection release, an arc extinguishing chamber 100, a partition, a first terminal, and a second terminal.

[0047] The circuit breaker housing 300 is used to accommodate these other components described above.

[0048] Here, the circuit breaker housing 300 is formed by a left housing 301 and a right housing 302, and after being assembled together, they are fixed with rivets.

[0049] As Figures 1 - 2 , Figures 4 - 5 shown, the operating mechanism adopts a four-bar linkage mechanism, and the operating mechanism is used to drive the closing and separating of the moving and static contacts. Here, the operating mechanism includes a handle 11, a contact support 14, and a locking structure. The locking structure includes a latch 13 and a pull rod assembly. The latch 13 is rotatably arranged on the contact support 14 (specifically, it is sleeved on the latch positioning post of the contact support 14 to form rotation). Here, the moving contact 30 is arranged on the contact support 14, so it can follow the movement of the contact support 14 to achieve contact and separation with the static contact.

[0050] According to different design forms of the pull rod assembly, there are two ways.

[0051] As Figure 6 , Figure 7 , Figure 8 and Figure 9 shown, in the first way, without a buckle, in this way, the pull rod assembly has only one pull rod 12, and its first end is connected to the handle 11. The contact support 14 has a first groove wall 14a, and the latch 13 is provided with a second groove wall 13a. The first groove wall 14a and the latch 13 together form a mating groove. Here, the mating groove has a locking section 134a and an unlocking section 134b. The second end of the pull rod 12 extends into the mating groove. When the circuit breaker is in the closed state, the second end is in the locking section 134a; when the circuit breaker is in the open state, the second end is in the unlocking section 134b. Since the latch 13 is rotatable relative to the contact support 14, the size of the mating groove will change with the relative position of the two. In this way, the contact support 14 also belongs to a part of the locking structure.

[0052] Taking the circuit breaker in the open state as an example, when it needs to be closed, push the handle 11 so that the second end of the pull rod 12 slides from the unlocking section 134b of the mating groove into the locking section 134a. At this time, since the latch 13 rotates under the action of the latch spring, the size of the mating groove is smaller than the diameter of the second end of the pull rod 12, so the locking of the pull rod 12 is completed, that is, it is in the locked state.

[0053] When the circuit breaker needs to be manually tripped, an external force is applied to push the handle 11, causing the second end of the pull rod 12 to squeeze the latch 13, which rotates the latch 13. As a result, the size of the locking section 134a is larger than the diameter of the second end of the pull rod 12, and the second end of the pull rod 12 cannot be locked. Therefore, the second end slides into the unlocking section 134b, and the operating mechanism completes the tripping operation.

[0054] Similarly, when the circuit breaker is in the closed state and an overload or short circuit occurs in the line, the overload protection release or the instantaneous protection release will drive the latch 13 to rotate, resulting in the size of the locking section 134a being larger than the diameter of the second end of the pull rod 12, and the second end of the pull rod 12 cannot be locked. Therefore, the second end slides into the unlocking section 134b, and the operating mechanism completes the tripping operation.

[0055] Method 2: There is a buckling method. In this method, the pull rod assembly includes a pull rod 12 and a buckle. The buckle is rotatably arranged on the contact support 14 (specifically, it is rotatably connected by sleeving on the buckle positioning post of the contact support 14). In this method, the buckle and the latch 13 have matching engaging parts. When the two engaging parts are engaged, a locked state is formed; when they are not engaged, an unlocked state is formed. Here, several situations of the unlocked state have been introduced in the above Method 1, and the situation of Method 2 is similar to it, so it will not be repeated here.

[0056] Of course, the operating mechanism also includes a main spring (used to perform the tripping operation and provide the medium pressure for the moving contact 30), a latch spring (used to reset the latch 13), a contact spring (providing the medium pressure for the moving contact 30), etc. Since these components are all conventional technical means in this field, they will not be elaborated here.

[0057] Whether it is the above Method 1 or Method 2, when the operating mechanism is in the closed state, the pull rod assembly and the latch 13 are in the locked state. When the operating mechanism is in the tripped state, the pull rod assembly and the latch 13 are in the unlocked state.

[0058] The instantaneous protection release adopts a solenoid electromagnet method, and its ejector rod is arranged towards the latch 13. The specific structure is common knowledge in this field and will not be elaborated here.

[0059] Such as Figure 4 、 Figure 5 、 Figure 7 and Figure 8As shown in the figure, an overload protection release uses a shape memory alloy 20. Here, the shape memory alloy 20 has an initial form CT and a transformed form BT. The initial form CT here is also called the martensite phase, and the transformed form BT is also called the austenite phase. When the temperature rises to the phase transition temperature, it will suddenly transform from the martensite phase to the austenite phase, that is, transform into the transformed form BT. When the temperature drops below the phase transition temperature, it will gradually transform from the austenite phase to the martensite phase, that is, restore the initial form CT. Simply put, taking the shape memory alloy 20 in the form of a compression spring as an example, when the temperature rises to the phase transition temperature, the size of the shape memory alloy 20 will stretch, equivalent to "lengthening"; when it returns below the phase transition temperature, the size of the shape memory alloy 20 will contract, equivalent to "shortening".

[0060] In this way, one end of the shape memory alloy 20 abuts against the contact support 14, and the other end abuts against the latch 13. When an overload occurs in the main circuit, when the internal temperature of the miniature circuit breaker (gradually rises above 60 °C) rises to the phase transition temperature of the shape memory alloy 20, the shape memory alloy 20 transforms from the initial form to the transformed form, and pushes the latch 13 to rotate to unlock it from the pull rod assembly, which can cause the operating mechanism to trip and complete the overload protection. When the temperature returns, the shape memory alloy 20 has also returned to its original state and will not prevent the closing of the operating mechanism.

[0061] The overload protection release using the shape memory alloy 20, compared with the traditional bimetallic strip form of overload protection release, overcomes the technical prejudice that the thermal release must be welded to the main circuit conductor and has the following advantages:

[0062] Compared with the prior art, the structure like this reduces the number of solder joints of the main circuit conductor by at least one (the shape memory alloy 20 does not need to be welded to the main circuit conductor), so the probability of false soldering is reduced and the performance of the product is guaranteed.

[0063] Since there is no bimetallic strip, the arc chute design of the circuit breaker will be simpler, and there is no need to additionally design the installation structure of the bimetallic strip (the prior art must design the corresponding installation structure), saving materials, simplifying the structure and the installation process.

[0064] Since the shape memory alloy 20 directly acts on the latch 13 and the bracket, it does not need to rely on a bimetallic pull rod 12 to drive the movement of the latch 13 as in the prior art. Therefore, such a structure also reduces the components of the operating mechanism, saves the space inside the circuit breaker, and simplifies the installation process.

[0065] In this embodiment, the shape memory alloy 20 is fixed on the operating mechanism, so that it can be assembled together with the operating mechanism. Such a setting method is beneficial to the automatic assembly of the product and simplifies the assembly process.

[0066] As Figure 9 , Figure 11 shown, specifically, a receiving cavity 140 is formed on the contact support 14. One side of the receiving cavity 140 has a trigger opening 141, and the shape memory alloy 20 is installed in the receiving cavity 140. A retaining wall exists at the trigger opening 141 where the latch 13 is located, so that one end of the shape memory alloy 20 can abut against the retaining wall and the other end can abut against the cavity wall of the receiving cavity 140. When the shape memory alloy 20 changes from its initial form to its deformed form, the shape memory alloy 20 "lengthens" to push the retaining wall, causing the latch 13 to rotate. This way of directly setting the shape memory alloy 20 on the receiving cavity 140 has the characteristics of a very simple assembly structure and trigger structure.

[0067] As Figure 11 shown, here, for the contact support 14, there is a main body portion 143 and a mounting portion 144; the mounting portion 144 is provided on the upper surface of the main body portion 143, and the receiving cavity 140 is provided in the mounting portion 144. The receiving cavity 140 here not only has the trigger opening 141, but also has a mounting opening 145, and the mounting opening 145 is opened on the upper surface of the mounting portion 144. In this way, the shape memory alloy 20 is loaded into the receiving cavity 140 from the mounting portion 144. Through the design of such a mounting portion 144 and the mounting opening 145, the installation of the shape memory alloy 20 will be very simple, and it can be directly pressed into the mounting opening from the front of the operating mechanism.

[0068] As Figure 9 shown, for such a mounting portion 144, it actually includes three walls, namely a first wall 144a, a second wall 144b, and a third wall 144c. The first wall 144a, the second wall 144b, and the third wall 144c together with the main body portion 143 surround to form the receiving cavity 140. Here, the first wall 144a is the side of the mounting portion 144 close to the stationary contact. Through such a surrounding arrangement, the mounting opening 145 and the trigger opening 141 are formed. Here, the second wall 144b, the third wall 144c, and the main body portion 143 all have notches 146. These notches 146 can reduce the contact area between the spring-shaped shape memory alloy 20 and the receiving cavity 140, so that the loss of force (due to friction) can be reduced. In this way, more force when the shape memory alloy 20 "stretches" can act on the latch 13, ensuring that the force to unlock the latch 13 is sufficient and realizing the quick opening of the operating mechanism.

[0069] Of course, it is not necessary to set such notches 146 on all of the second wall 144b, the third wall 144c, and the main body portion 143. As long as any one of the three has a notch, the loss of force can be reduced.

[0070] AsFigure 11 As shown, here, there is an anti - detachment protrusion 147 on the first wall 144a. The anti - detachment protrusion 147 is actually a small protrusion. Since both ends of the spring - shaped shape - memory alloy 20 are already abutted between the retaining wall of the latch 13 and the first wall 144a, just having a small protrusion can prevent the spring - shaped shape - memory alloy 20 from easily detaching from the installation opening 145 and leaving the accommodation cavity 140.

[0071] Of course, there are many ways to set the anti - detachment protrusion 147 here. For example, it can be set on the second wall 144b or the third wall 144c, or on all three walls, or on two of the walls. No matter which form, it can prevent the spring - shaped shape - memory alloy 20 from easily detaching from the installation opening 145 and leaving the accommodation cavity 140.

[0072] As Figure 7 、 Figure 8 and Figure 10 shown, as for the latch 13, it has a body part 130, and here the body part 130 is set on the upper surface of the contact support 14. Here, a through - hole 131 is opened on the body part 130, so that the upper installation part 144 can penetrate into the through - hole 131. Since there are side walls around the through - hole 131, and these walls include a first side wall 131a and a second side wall 131b, and the first side wall 131a and the second side wall 131b are two opposite walls. Here, the second side wall 131b is actually the retaining wall mentioned above, that is, one end of the shape - memory alloy 20 abuts against the second side wall 131b and the other end abuts against the first wall 144a. Here, there is a first avoidance gap D1 between the first side wall 131a and the installation part 144. This avoidance gap is to reserve space for the movement of the installation part 144, because when the shape - memory alloy 20 "elongates", the first wall 144a of the installation part 144 will move towards the direction where the first side wall 131a is located. Simply put, the size of the first avoidance gap D1 is larger when the shape - memory alloy 20 is in the initial state CT than when it is in the changed state BT.

[0073] Such a through - hole 131 structure combined with the insertion of the installation part 144 is conducive to the shape - memory alloy 20 completing the end - abutting assembly. At the same time, the setting of the first avoidance gap D1 can make the whole movement structure more reasonable and ensure the structure of the overall product is more stable.

[0074] As Figure 10As shown, here, the upper surface of the latch 13 has an annular portion 132 around the through hole 131. In fact, it can also be said that the hollow part of the annular portion 132 is also part of the through hole 131. The reason for adopting the design of the annular portion 132 is that the entire mounting portion 144 can be arranged without exceeding the annular portion 132. In this way, the annular portion 132 can play a certain protective effect on the mounting position of the shape memory alloy 20, and at the same time, it also improves the size of the installation space for the shape memory alloy 20 during deformation.

[0075] As Figure 4 , Figure 5 shown, through the setting of the shape memory alloy 20 in this way, the moving contact 30 and the conductive sheet 40 can be directly connected by soft connection welding. In fact, there will be only two solder joints between the two, that is, no more than three. Of course, here for the conductive sheet 40, it can be an integral part with the terminal board of the second terminal or welded and fixed. No matter which method is used, the structure of the above-mentioned shape memory alloy 20 will reduce the number of solder joints compared with the bimetallic sheet structure and reduce the risk of false soldering (because the more solder joints there are, the greater the possibility of false soldering is amplified).

[0076] Through the above method, the electrical connection between the second terminal and the moving contact 30 is completed.

[0077] As for the first terminal, it is electrically connected to the static contact. The specific connection method is that the terminal board, solenoid, static contact and other components of the first terminal are welded together in sequence. This connection method is already common knowledge and will not be elaborated here.

[0078] That is to say, in this case, when the first terminal and the second terminal are connected to the external circuit, this miniature circuit breaker can be connected to the circuit to protect the circuit.

[0079] During the separation process of the moving and static contacts, there will inevitably be an arc. To extinguish the arc, the arc extinguishing chamber 100 is arranged near the moving and static contacts.

[0080] As Figure 16 shown, the arc extinguishing chamber 100 includes arc extinguishing grid plates 110 and a bracket for fixing the arc extinguishing grid plates 110. In this embodiment, the bracket for fixing the arc extinguishing grid plates 110 is two side plates.

[0081] As Figure 16As shown, there are a total of fifteen arc extinguishing grid sheets 110, which are stacked in sequence along the first direction F1. Here, it can be seen from the drawings of the circuit breaker that the first direction F1 is equivalent to the height direction. Of course, the first direction F1 here is not limited to the height direction of the circuit breaker. For example, if the arc extinguishing chamber 100 adopts a lying structure, then the first direction F1 is the length direction. There is a gap between two adjacent arc extinguishing grid sheets 110, and this gap is the first gap 110a. In this embodiment, the number of the first gaps 110a is fourteen. Of course, the arc extinguishing grid sheets 110 here are not limited to fifteen, and any number more than seven is acceptable.

[0082] As Figure 16 shown, for the arc extinguishing chamber 100, it includes a front end M1 and a rear end M2. Here, the front end M1 refers to the end of the arc extinguishing grid sheet 110 facing the moving and static contacts. There are arc extinguishing grooves on this end, allowing the arc to stretch here, so as to extinguish the arc. Here, the rear end M2 refers to the end far from the front end M1. Generally, some gas will be generated as the arc extinguishes after breaking, and the gas will flow from the front end M1 to the rear end M2.

[0083] As Figure 1 、 Figure 3 shown, for the circuit breaker housing 300, it has a first air duct 310 and a second air duct 320. The first air duct 310 and the second air duct 320 are separated by a partition rib 330 on the circuit breaker housing 300. The partition rib 330 can be a part integrally formed with the circuit breaker housing 300, or a part formed separately and then installed on the circuit breaker housing 300 by means of a clamping assembly structure.

[0084] As Figure 1 、 Figure 3 shown, before the arc gas enters the first air duct 310 and the second air duct 320, it will be divided by a separator. Here, the separator is fixed to the rear end M2 of the arc extinguishing chamber 100. The rear end M2 of the arc extinguishing chamber 100 is divided into four parts by the separator, namely a first upper region S1, a first lower region S2, a second upper region S3, and a second lower region S4. The first upper region S1 and the second upper region S3 are both communicated with the first air duct 310, and the second upper region S3 and the second lower region S4 are both communicated with the second air duct 320.

[0085] As Figure 12 、 Figure 13 shown, specifically, the separator 200 has a first partition rib 210 and a second partition rib. The first partition rib 210 and the second partition rib intersect vertically and horizontally to divide the rear end M2 of the arc extinguishing chamber 100 into the above four regions. Here, the first partition rib 210 is equivalent to a longitudinal rib. The second partition rib includes a second sub-partition rib Ⅰ220 and a second sub-partition rib Ⅱ230, which are equivalent to two transverse ribs.

[0086] As Figure 12 , Figure 13 shown, the second sub-septum I 220 and the second sub-septum II 230 are arranged in a staggered manner here, that is, the shape formed by connecting the two is not a straight structure, but is similar to a Z-shape. After such an arrangement, the first upper region S1 and the first lower region S2 are jointly divided by the first septum 210 and the second sub-septum I 220, and the first upper region S1 is smaller than the first lower region S2; the second upper region S3 and the second lower region S4 are jointly divided by the first septum 210 and the second sub-septum II 230, and the second upper region S3 is larger than the second lower region S4.

[0087] As Figure 12 , Figure 13 shown, in this embodiment, the first upper region S1 is smaller than the first lower region S2, and the second upper region S3 is larger than the second lower region S4. Therefore, the number of the first intervals 110a in the first upper region S1 is less than the number of the first intervals 110a in the first lower region S2; the number of the first intervals 110a in the second upper region S3 is more than the number of the first intervals 110a in the second lower region S4. Of course, no matter how it is divided, for the first interval 110a, the number of it in each region is not less than two.

[0088] As Figure 13 shown, the separator 200 has a gas blocking portion 240 in each region, and here the gas blocking portion 240 blocks the rear end M2 of the first interval 110a. Of course, not all the rear ends M2 of the first intervals 110a in each region are blocked by the gas blocking portion 240, but a part of the first intervals 110a are blocked by the gas blocking portion 240. Simply put, the total number of the gas blocking portions 240 in each region is less than the total number of the first intervals 110a. Such a structure can effectively increase the air pressure, accelerate the gas flow, and improve the arc extinguishing effect by blocking part of the first intervals 110a. Of course, the gas blocking portion 240 here can only be said to block a part of the first intervals 110a, because the first interval 110a generally spans two regions, and the gas blocking portion 240 in each region is bound to only block a part of the first interval 110a.

[0089] As Figure 13As shown, here, the second sub-separating rib I 220 and the second sub-separating rib II 230 also bear part of the effect of the gas-blocking part 240. That is, the second sub-separating rib I 220 is located at the rear end M2 of a first interval 110a and blocks a part of it. The second sub-separating rib II 230 is also located at the rear end M2 of a first interval 110a and blocks a part of it. The first interval 110a blocked by the second sub-separating rib I 220 is different from the first interval 110a blocked by the second sub-separating rib II 230. Here, the first interval 110a blocked by the second sub-separating rib I 220 and the first interval 110a blocked by the second sub-separating rib II 230 are two first intervals 110a closer to the middle part of the arc extinguishing chamber 100. Similarly, the second sub-separating rib I 220 and the second sub-separating rib II 230 here can only be said to block a part of the first interval 110a because the first interval 110a generally spans two regions, while the second sub-separating rib I 220 and the second sub-separating rib II 230 do not span two regions.

[0090] As Figure 13 shown, generally speaking, the first interval 110a whose rear end M2 in the first upper region S1 is blocked by the gas-blocking part 240 is exposed in the second upper region S3. And the first interval 110a whose rear end M2 in the second upper region S3 is blocked by the gas-blocking part 240 is exposed in the first upper region S1. The first interval 110a whose rear end M2 in the first lower region S2 is blocked by the gas-blocking part 240 is exposed in the second lower region S4. The first interval 110a whose rear end M2 in the second lower region S4 is blocked by the gas-blocking part 240 is exposed in the first lower region S2.

[0091] As Figure 15 shown, here, for the convenience of the assembly between the separator 200 and the arc extinguishing chamber 100. An inserting rib 250 is provided on the gas-blocking part 240, and the inserting rib 250 is inserted into the blocked first interval 110a. In this way, the separator 200 and the arc extinguishing chamber 100 also form a plug-in fit, which is beneficial to improving the stability. Of course, there are many specific forms of the inserting rib 250 here, such as strip-shaped or convex point-shaped.

[0092] As Figure 14As shown, here, although the first side plate 205 and the second side plate 215 are located on two sides of the arc extinguishing grid 110, there is a distance between them and the rear end M2, and all the air blocking parts 240 are bent and extended onto the side surface of the arc extinguishing grid 110. The air blocking parts 240 in the first upper region S1 and the first lower region S2 and the second sub-separating rib I 220 are connected by the first abutting rib 260, and the first abutting rib 260 is located beside the first side plate 205 and abuts against the first side plate 205. The air blocking parts 240 in the second upper region S3 and the second lower region S4 and the second sub-separating rib II 230 are connected by the second abutting rib 270, and the second abutting rib 270 is located beside the second side plate 215 and abuts against the second side plate 215. The arrangement of the first abutting rib 260 and the second abutting rib 270 makes the separator 200 stronger, and at the same time, it can also be in abutting cooperation with the side plates.

[0093] As Figure 1 , Figure 3 shown, the above-mentioned first air passage 310 and second air passage 320 are separated by the separating rib 330 on the circuit breaker housing 300. Here, the separating rib 330 is also arranged in two staggered positions to be adapted to the two staggered second sub-separating ribs I 220 and second sub-separating ribs II 230 respectively.

[0094] As Figure 1 , Figure 3 , Figure 17 and Figure 18 shown, the circuit breaker housing 300 is also formed with a first guiding rib 340a, a second guiding rib 340b, a third guiding rib 340c and a fourth guiding rib 340d. Here, the first guiding rib 340a and the second guiding rib 340b are both distributed in the first air passage 310. The first guiding rib 340a is arranged at the rear end M2 of the first upper region S1, and the second guiding rib 340b is arranged at the rear end M2 of the second upper region S3. The third guiding rib 340c and the fourth guiding rib 340d are both distributed in the second air passage 320. The third guiding rib 340c is arranged at the rear end M2 of the first upper region S1, and the fourth guiding rib 340d is arranged at the rear end M2 of the second lower region S4. The guiding ribs correspond to the air blocking parts 240 in the corresponding regions, so that the air flow can be guided by the guiding ribs, which is beneficial to controlling the flow direction of the gas.

[0095] As Figure 1 , Figure 3 , Figure 17 and Figure 18 shown, here, both the first guiding rib 340a and the second guiding rib 340b are inclined upward, specifically, they are inclined upward from the direction where the arc extinguishing structure is located to the direction away from the direction where the arc extinguishing structure is located. In this way, the gas from the first upper region S1 and the second upper region S3 can be guided to move upward.

[0096] As Figure 1 , Figure 3 , Figure 17 and Figure 18 shown, here, the first guiding rib 340a and the second guiding rib 340b are arranged in a staggered manner. Such a staggered arrangement is more adaptable to the corresponding gas blocking part 240, which is beneficial to the design of the gas flow path.

[0097] As Figure 1 , Figure 3 , Figure 17 and Figure 18 shown, here, the third guiding rib 340c and the fourth guiding rib 340d are both inclined downward, specifically inclined downward from the direction where the arc extinguishing structure is located to the direction away from the direction where the arc extinguishing structure is located. This can guide the gas from the first lower region S2 and the second lower region S4 to move downward.

[0098] As Figure 1 , Figure 3 , Figure 17 and Figure 18 shown, here, the third guiding rib 340c and the fourth guiding rib 340d are arranged in a staggered manner. Such a staggered arrangement is more adaptable to the corresponding gas blocking part 240, which is beneficial to the design of the gas flow path.

[0099] As Figure 1 , Figure 3 shown, finally, the gas passing through the first air passage 310 is discharged through the first exhaust hole on the circuit breaker housing 300, and the gas passing through the second air passage 320 is discharged through the second exhaust hole on the circuit breaker housing 300 or circulates to the front end M1 of the arc extinguishing chamber 100 through the internal circulation air passage.

[0100] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0101] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A miniature circuit breaker, comprising an operating mechanism, a moving contact, a static contact and a conductive sheet. The operating mechanism includes a contact support and a locking structure; the locking structure includes a latch rotatably arranged on the contact support and a pull rod assembly; the pull rod assembly and the latch have an unlocked state and a locked state, and the operating mechanism includes a closing state and a tripping state; when the operating mechanism is in the closing state, the pull rod assembly and the latch are in the locked state; when the operating mechanism is in the tripping state, the pull rod assembly and the latch are in the unlocked state; it is characterized in that: It further includes a shape memory alloy, one end of the shape memory alloy abuts against the contact support, and the other end abuts against the latch; the shape memory alloy has an initial form and a transformed form; after an overload occurs in the main circuit, when the internal temperature of the miniature circuit breaker rises to the phase change temperature of the shape memory alloy, the shape memory alloy changes from the initial form to the transformed form, and pushes the latch to rotate to unlock it from the tie rod assembly, prompting the operating mechanism to trip; a receiving cavity is formed on the contact support, one side of the receiving cavity has a triggering opening, and there is a retaining wall at the position where the latch is located at the triggering opening; the shape memory alloy is installed in the receiving cavity, one end passes through the triggering opening and abuts against the retaining wall, and the other end abuts against the cavity wall of the receiving cavity; when the shape memory alloy changes from the initial form to the transformed form, the latch is rotated by pushing the retaining wall.

2. The miniature circuit breaker according to claim 1, characterized in that: The contact support includes a main body portion and a mounting portion; the mounting portion is provided on the upper surface of the main body portion, and the receiving cavity is provided in the mounting portion; the receiving cavity also has a mounting opening, the mounting opening is opened on the upper surface of the mounting portion, and the shape memory alloy is loaded into the receiving cavity from the mounting portion.

3. A miniature circuit breaker according to claim 2, characterized in that: The mounting portion includes a first wall, a second wall and a third wall, and the first wall, the second wall, the third wall and the main body portion jointly enclose to form the receiving cavity; the first wall is the side of the mounting portion close to the static contact, and the triggering opening is opened on the side of the mounting portion away from the first wall; at least any one of the second wall, the third wall and the main body portion is provided with a notch; the shape memory alloy is in the shape of a compression spring, and the notch is used to reduce the contact area between the shape memory alloy and the receiving cavity.

4. A miniature circuit breaker according to claim 2, characterized in that: The mounting portion includes a first wall, a second wall and a third wall, and the first wall, the second wall, the third wall and the main body portion jointly form the receiving cavity; at least any one of the first wall, the second wall and the third wall is provided with an anti-disengagement protrusion; the shape memory alloy is in the shape of a compression spring, and the anti-disengagement protrusion abuts against the shape memory alloy to prevent the shape memory alloy from disengaging from the receiving cavity through the mounting opening.

5. The miniature circuit breaker according to claim 2, characterized in that: The latch has a body portion provided on the upper surface of the contact support; a through hole is opened on the upper surface of the body portion, and at least a part of the mounting portion penetrates into the through hole; the through hole has a first side wall and a second side wall arranged oppositely, and the retaining wall is the second side wall; there is a first avoidance gap between the first side wall and the mounting portion, and the size of the first avoidance gap when the shape memory alloy is in the initial form is larger than the size when the shape memory alloy is in the transformed form.

6. A miniature circuit breaker according to claim 5, characterized in that: The upper surface of the body portion has an annular portion, and the hollow part of the annular portion also belongs to a part of the through hole, and the mounting portion does not extend beyond the hollow part of the annular portion.

7. A miniature circuit breaker according to claim 1, characterized in that: The moving contact is connected to the conductive sheet through a flexible connection, and the number of solder joints among the three is less than three.

8. A miniature circuit breaker according to claim 1, characterized in that: The operating mechanism further includes a handle, the tie rod assembly includes a tie rod and a buckle, one end of the tie rod is connected to the buckle, the buckle is rotatably arranged on the contact support, and the locked state and the unlocked state of the tie rod assembly and the latch are realized by the buckle and the latch; Alternatively, the operating mechanism further includes a handle. The pull rod assembly includes a pull rod. The contact support also serves as a part of the locking structure. A first groove wall is provided on the contact support, and a second groove wall is provided on the latch. One end of the pull rod is connected to the handle, and the other end of the pull rod extends into the mating groove formed by the first groove wall and the second groove wall. By changing the relative angle between the latch and the contact support, the gap between the first groove wall and the second groove wall changes, thereby realizing the locking and unlocking of the pull rod.

9. A miniature circuit breaker according to any one of claims 1-8, characterized in that: It further includes a circuit breaker housing, an arc extinguishing chamber, and a separator; the circuit breaker housing has an arc extinguishing chamber, a first air passage, and a second air passage located at the rear of the arc extinguishing chamber; the arc extinguishing chamber and the separator are arranged in the arc extinguishing chamber, and the separator is fixed to the rear end of the arc extinguishing chamber; the separator includes a first partition rib and a second partition rib, the first partition rib and the second partition rib are crisscrossed and divide the rear part of the arc extinguishing cover into a first upper region, a first lower region, a second upper region, and a second lower region; the first upper region and the second upper region are both communicated with the first air passage, and the second upper region and the second lower region are both communicated with the second air passage.

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