Novel miniature circuit breaker

Abstract

The invention discloses a novel miniature circuit breaker, which comprises an operating mechanism, a moving contact, a static contact and a conducting strip, and is characterized in that the operating mechanism comprises a contact support and a locking structure; the locking structure comprises a lock catch rotationally arranged on the contact support and a pull rod assembly; the switch further comprises a shape memory alloy, one end of the shape memory alloy abuts against the contact support, and the other end of the shape memory alloy abuts against the lock catch. The shape memory alloy has an initial form and a change form; after a main line is overloaded, when the internal temperature of the miniature circuit breaker rises to the phase change temperature of the shape memory alloy, the shape memory alloy is converted into a change form from an initial form, the lock catch is pushed to rotate to be unlocked from the pull rod assembly, and the operating mechanism is promoted to trip; the overload tripping device has a novel overload tripping structure.

Description

Technical Field

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

[0002] A small circuit breaker can provide overload protection and short-circuit protection. Existing small circuit breakers rely on bimetallic strips to provide overload protection. The specific structure is that one end of the bimetallic strip is welded to the moving contact through a soft connection, and the other end is welded to a conductive sheet integrated with the terminal board. When the main line is overloaded, the temperature on the bimetallic strip continues to rise, and the bimetallic strip gradually bends. Finally, the bimetallic pull rod pulls the lock of the operating mechanism to achieve overload protection. For example, a small circuit breaker thermal trip mechanism and a small circuit breaker having the same disclosed in CN208489161U adopt this structure. This type of overload protection has existed for decades or even hundreds of years, and it has some limitations.

[0003] Problem 1: Since the bimetallic strip needs to be welded in the main line conductor, there are at least three welding points here, namely the welding point between the moving contact and the soft connection, the welding point between the soft connection and the bimetallic strip, and the welding point between the bimetallic strip and the conductive strip. In some cases, the conductive strip is also an independent part that needs to be welded to the terminal board (so there are more welding points). As for the welding process, it is inevitable that there is a possibility of cold welding. Therefore, the more welding points there are, the greater the possibility of cold welding. Cold welding will cause the contact resistance to increase, causing the bimetallic strip to heat up more quickly, and there may be a possibility of false tripping (tripping caused by the temperature reaching the value of bending the bimetallic strip without overload).

[0004] The second problem is that the existing bimetallic strip is fixed on the arc track, which means that the arc track also needs to be provided with a matching structure for its welding and installation, which invisibly increases the difficulty of designing the arc track and the waste of materials.

[0005] Third, the bimetallic strip needs to drive the lock to move through a bimetallic pull rod. The design of the bimetallic pull rod also needs to take into account the 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 overload protection structure is a problem worth exploring for small 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 to provide a new type of miniature circuit breaker.

[0008] The present application provides: a novel small circuit breaker, comprising an operating mechanism, a moving contact, a stationary contact and a conductive sheet, wherein the operating mechanism comprises a contact support and a locking structure; the locking structure comprises a lock catch and a pull rod assembly rotatably arranged on the contact support; the pull rod assembly and the lock catch exist in an unlocked state and a locked state, and the operating mechanism comprises a closed state and an open state; when the operating mechanism is in the closed state, the pull rod assembly and the lock catch are in a locked state; when the operating mechanism is in the open state, the pull rod assembly and the lock catch are in an unlocked state; wherein, it also comprises a shape memory alloy, 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 changed form; after an overload occurs in the main line, when the internal temperature of the small circuit breaker rises to the phase transition temperature of the shape memory alloy, the shape memory alloy changes from the initial form to the changed form, and pushes the lock catch to rotate so that it is unlocked from the pull rod assembly, causing the operating mechanism to trip.

[0009] In some embodiments of the present application, a accommodating cavity is formed on the contact support, and a trigger opening is provided on one side of the accommodating cavity, and the trigger opening is arranged on the side of the mounting portion away from the static contact; there is a retaining wall at the trigger opening of the lock, and the shape memory alloy is installed in the accommodating cavity, and one end of the shape memory alloy is against the retaining wall through the trigger opening, and the other end is against the cavity wall of the accommodating cavity; the shape memory alloy changes from an initial form to a changed form, and the lock rotates by pushing the retaining wall.

[0010] In some embodiments of the present application, the contact support includes a main body and a mounting portion; the mounting portion is arranged on the upper surface of the main body, and the accommodating cavity is arranged in the mounting portion; the accommodating cavity also has an installation opening, the installation opening is opened on the upper surface of the mounting portion, and the shape memory alloy is loaded into the accommodating cavity by 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, and the first wall, the second wall, the third wall and the main body together form a accommodating cavity; the first wall is a side of the mounting portion close to the static contact, and the trigger opening is opened on a 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 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 accommodating cavity.

[0012] In some embodiments of the present application, 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 together form a accommodating cavity; at least any one of the first wall, the second wall and the third wall is provided with an anti-slip protrusion; the shape memory alloy is in the shape of a compression spring, and the anti-slip protrusion is offset against the shape memory alloy to limit the shape memory alloy from escaping from the accommodating cavity from the mounting opening.

[0013] In some embodiments of the present application, the lock has a main body portion arranged on the upper surface of the contact support; a through hole is opened on the upper surface of the main body portion, and the mounting portion at least partially penetrates into the through hole; the through hole has a first side wall and a second side wall arranged opposite to each other, 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 changed form.

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

[0015] In some embodiments of the present application, the moving contact and the conductive sheet are connected via a soft connection, and the number of welding points between the three is less than three.

[0016] In some embodiments of the present application, the operating mechanism also 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 set on the contact support, and the locking state and unlocking state of the pull rod assembly and the buckle are realized by the buckle and the lock.

[0017] In some embodiments of the present application, the operating mechanism also includes a handle, the pull rod assembly includes a pull rod, and the contact support is also a component of the locking structure. A first groove wall is provided on the contact support, and a second groove wall is provided on the lock buckle. One end of the pull rod is connected to the handle, and the other end of the pull rod extends into a matching groove formed by the first groove wall and the second groove wall. The relative angle between the lock buckle and the contact support changes, so that the gap between the first groove wall and the second groove wall changes, thereby achieving locking and unlocking of the pull rod.

[0018] In some embodiments of the present application, it also includes a circuit breaker housing, an arc extinguishing chamber and a partition; the circuit breaker housing has an arc extinguishing chamber and a first air duct and a second air duct located at the rear of the arc extinguishing chamber, and the first air duct is connected to the arc extinguishing chamber; the arc extinguishing chamber and the partition are arranged in the arc extinguishing chamber, and the partition is fixed at the rear end of the arc extinguishing chamber; the partition 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 area, a first lower area, a second upper area and a second lower area; the first upper area and the second upper area are both connected to the first air duct, and the second upper area and the second lower area are both connected to the second air duct.

[0019] Compared with the prior art, the present invention has the following advantages: The above structure overcomes the technical prejudice that the thermal release must be welded in the main line conductor, uses the shape memory alloy to directly sense the internal temperature of the circuit breaker, uses the shape change after its phase change, acts on the lock to cause the operating mechanism to trip, and realizes overload protection, replacing the bending of the traditional bimetallic strip to realize overload protection. It has the following advantages: First, compared with the prior art, such a structure reduces the number of welding points of the main line conductor by at least one (because the shape memory alloy does not need to be welded on the main line conductor), thereby reducing the probability of cold welding and ensuring the performance of the product. Second, since there is no bimetallic strip, the arc running track design of the circuit breaker will be simpler, and there is no need to design the installation position of the bimetallic strip additionally (the prior art must design the corresponding installation position), saving materials, simplifying the structure and installation process. Third, since the shape memory alloy acts directly on the lock and bracket, it does not need to rely on a bimetallic pull rod to drive the lock movement like the prior art, so such a structure also reduces the components of the operating mechanism and simplifies the installation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 A schematic diagram showing the interior of a miniature circuit breaker according to an embodiment of the present application is shown; Figure 2 A three-dimensional diagram of a miniature circuit breaker according to an embodiment of the present application is shown; Figure 3 A schematic diagram showing another perspective of the interior of a miniature circuit breaker according to an embodiment of the present application; Figure 4 A schematic diagram showing a small circuit breaker in an embodiment of the present application in a closed state and a shape memory alloy in an initial state; Figure 5 A schematic diagram showing a small circuit breaker in an open state and a shape memory alloy in a changed state according to an embodiment of the present application is shown; Figure 6 A schematic diagram showing contact support and locking in an embodiment of the present application is shown; Figure 7 A schematic diagram showing the support of the lock and the contact when the shape memory alloy is in the initial state in the embodiment of the present application; Figure 8 A schematic diagram showing the support of the lock and the contact when the shape memory alloy in the embodiment of the present application is in a changed state; Fig. 9 A schematic diagram showing contact support in an embodiment of the present application is shown; Fig.10 A schematic diagram of a lock buckle in an embodiment of the present application is shown; Fig.11 A schematic diagram showing a shape memory alloy and a contact support in an embodiment of the present application is shown; Fig.12 A three-dimensional diagram of a separator and an arc extinguishing chamber in an embodiment of the present application is shown; Fig.13 A rear view of a separator and an arc extinguishing chamber in an embodiment of the present application is shown; Fig.14 A three-dimensional diagram of the separator and the arc extinguishing chamber from another perspective in the embodiment of the present application is shown; Fig.15 A three-dimensional diagram of a separator in an embodiment of the present application is shown; Fig.16 A three-dimensional diagram of an arc extinguishing chamber in an embodiment of the present application is shown; Fig.17 A cross-sectional view of a circuit breaker housing in an embodiment of the present application is shown; Fig.18 A cross-sectional view of the first and second air passages of a novel miniature circuit breaker according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0022] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0023] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0024] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0025] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0026] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature. Example

[0027] like Figure 1-Figure 2 As shown, the embodiment of the present application is a new type of miniature circuit breaker.

[0028] The miniature circuit breaker comprises a circuit breaker housing 300, moving contacts, static contacts, an operating mechanism, an overload protection release, an instantaneous protection release, an arc extinguishing chamber 100, a separator, a first wiring terminal and a second wiring terminal.

[0029] The circuit breaker housing 300 is used to accommodate the other components mentioned above.

[0030] The circuit breaker housing 300 is formed by a left housing 301 and a right housing 302, which are assembled and fixed with rivets.

[0031] like Figure 1-Figure 2 , Figure 4-Figure 5As shown, the operating mechanism adopts a four-bar linkage mechanism, and the operating mechanism is used to drive the connection and separation 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 lock 13 and a pull rod assembly. The lock 13 is rotatably arranged on the contact support 14 (specifically, it is sleeved on the lock 13 positioning column of the contact support 14 to form a 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.

[0032] There are two methods according to the different designs of the tie rod assembly.

[0033] like Figure 6 , Figure 7 , Figure 8 and Fig. 9 As shown, method one is a buckle-free method. In this method, 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 lock buckle 13 is provided with a second groove wall 13a. The first groove wall 14a and the lock buckle 13 together form a matching groove, and the matching groove here has a locking section 134a and an unlocking section 134b. The second end of the pull rod 12 extends into the matching 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 lock buckle 13 is rotatable relative to the contact support 14, the size of the matching groove will change with the relative position of the two. In this method, the contact support 14 is also part of the locking structure.

[0034] Taking the circuit breaker in the open state as an example, when it needs to be closed, the handle 11 is pushed so that the second end of the pull rod 12 slides from the unlocking section 134b of the matching groove into the locking section 134a. At this time, the lock buckle 13 rotates under the action of the lock buckle spring, so that the size of the matching groove is smaller than the diameter of the second end of the pull rod 12, thereby completing the locking of the pull rod 12, that is, it is in a locked state.

[0035] When the circuit breaker needs to be manually opened, an external force pushes the handle 11 so that the second end of the pull rod 12 squeezes the lock 13 and rotates the lock 13, 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.

[0036] Similarly, when the circuit breaker is in the closed state and the line is overloaded or short-circuited, the overload protection release or the instantaneous protection release will drive the lock 13 to rotate, causing the size of the locking section 134a to be 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.

[0037] Method 2 is a buckle 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 sleeved on the buckle positioning column on the contact support 14 to form a rotatable connection). In this method, the buckle and the lock buckle 13 have an adaptive bite part. When the bite parts of the two bite each other, a locked state is formed; when the two do not bite each other, an unlocked state is formed. Here, the above method 1 has introduced several situations of the unlocked state, and the situation of method 2 is also similar to it, so it will not be repeated here.

[0038] Of course, the operating mechanism also includes a main spring (used to perform the opening operation and provide the medium pressure of the moving contact 30), a lock spring (used to reset the lock 13), a contact spring (providing the medium pressure of the moving contact 30) and other components. Since these components are already conventional technical means in this field, they will not be described in detail here.

[0039] In either the above-mentioned method 1 or method 2, when the operating mechanism is in the closing state, the rod assembly and the lock catch 13 are in the locked state. When the operating mechanism is in the opening state, the rod assembly and the lock catch 13 are in the unlocked state.

[0040] The instantaneous protection release adopts a solenoid type electromagnet, and its top rod is arranged toward the lock buckle 13. The specific structure is common knowledge in the field and will not be described here.

[0041] like Figure 4 , Figure 5 , Figure 7 as well as Figure 8 As shown, the overload protection release adopts a shape memory alloy 20. Here, the shape memory alloy 20 has an initial form CT and a change form BT. The initial form CT is also called the martensite phase, and the change form BT is also called the austenite phase. When the temperature rises to the phase transition temperature, it will suddenly change from the martensite phase to the austenite phase, that is, it will change to the change form BT. When the temperature drops below the phase transition temperature, it will gradually change 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, which is equivalent to "lengthening"; and when it returns to below the phase transition temperature, the size of the shape memory alloy 20 will shrink, which is equivalent to "shortening".

[0042] In this way, one end of the shape memory alloy 20 is against the contact support 14, and the other end is against the lock 13. When the main line is overloaded, the internal temperature of the small circuit breaker (which will gradually rise to above 60°C) rises to the phase change temperature of the shape memory alloy 20, and the shape memory alloy 20 changes from the initial form to the changed form, and pushes the lock 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 recovers, the shape memory alloy 20 has also returned to its original state and will not hinder the closing of the operating mechanism.

[0043] Compared with the traditional bimetallic overload protection release, the overload protection release of shape memory alloy 20 overcomes the technical prejudice that the thermal release must be welded in the main line conductor, and has the following advantages: Compared with the prior art, this structure reduces the number of welding points of the main line conductor by at least one (the shape memory alloy 20 does not need to be welded on the main line conductor), thereby reducing the probability of cold welding and ensuring the performance of the product.

[0044] Since there is no bimetallic strip, the arc track design of the circuit breaker will be simpler, and there is no need to additionally design a mounting structure for the bimetallic strip (the prior art requires the design of a corresponding mounting structure), which saves materials and simplifies the structure and installation process.

[0045] Since the shape memory alloy 20 directly acts on the lock 13 and the bracket, it does not need to rely on a double metal pull rod 12 to drive the lock 13 to move like the prior art. Therefore, such a structure also reduces the components of the operating mechanism, saves space inside the circuit breaker, and simplifies the installation process.

[0046] 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. This arrangement is conducive to the automated assembly of the product and simplifies the assembly process.

[0047] like Fig. 9 , Fig.11 As shown, specifically, a receiving cavity 140 is formed on the contact support 14, and a trigger opening 141 is provided on one side of the receiving cavity 140, and the shape memory alloy 20 is installed in the receiving cavity 140. There is a retaining wall at the trigger opening 141 of the lock buckle 13, 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 the initial form to the changed form, the shape memory alloy 20 "becomes longer" and pushes the retaining wall to make the lock buckle 13 rotate. This method of directly setting the shape memory alloy 20 on the receiving cavity 140 has the characteristics of very simple assembly structure and trigger structure.

[0048] like Fig.11 As shown, here, for the contact support 14, the main body 143 and the mounting part 144; the mounting part 144 is arranged on the upper surface of the main body 143, and the accommodating cavity 140 is arranged in the mounting part 144. Here, the accommodating cavity 140 is provided with not only a trigger opening 141, but also an installation opening 145, and the installation opening 145 is opened on the upper surface of the mounting part 144. In this way, the shape memory alloy 20 is loaded into the accommodating cavity 140 through the mounting part 144. Through the design of such a mounting part 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 installation opening from the front of the operating mechanism.

[0049] like Fig. 9 As shown, for this 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 and the main body 143 surround and form a receiving cavity 140. Here, the first wall 144a is the side of the mounting portion 144 close to the static contact. Through such a surrounding arrangement, a mounting opening 145 and a trigger opening 141 are formed. Here, the second wall 144b, the third wall 144c and the main body 143 are all provided with notches 146. These notches 146 can reduce the contact area between the compression spring-shaped shape memory alloy 20 and the receiving cavity 140, so that the loss of force (loss due to friction) can be reduced, so that the force of the shape memory alloy 20 when "stretching" can act more on the lock buckle 13, ensuring that the force to unlock the lock buckle 13 is sufficient, and realizing the rapid opening of the operating mechanism.

[0050] Of course, the notch 146 does not have to be provided on the second wall 144b, the third wall 144c and the main body 143. As long as it is provided on any one of the three, the loss of force can be reduced.

[0051] like Fig.11 As shown, here, there is an anti-slip protrusion 147 on the first wall 144a, and the anti-slip protrusion 147 here is actually a small protrusion. Since both ends of the compression spring-shaped shape memory alloy 20 have been abutted between the retaining wall of the lock buckle 13 and the first wall 144a, only a small protrusion is needed to prevent the compression spring-shaped shape memory alloy 20 from easily escaping from the accommodating cavity 140 from the installation opening 145.

[0052] Of course, there are many other ways to set the anti-slip protrusion 147 here, such as setting it on the second wall 144b or the third wall 144c, or setting it on all three walls, or setting it on two of the walls. Either form can prevent the compression spring-shaped shape memory alloy 20 from easily escaping from the accommodating cavity 140 from the installation opening 145.

[0053] like Figure 7 , Figure 8 as well as Fig.10 As shown, as for the lock buckle 13, it has a body part 130, and the body part 130 is arranged 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 mounting part 144 can be inserted into the through hole 131. Since there are side walls around the through hole 131, 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 on the second side wall 131b, and the other end abuts on the first wall 144a. Here, there is a first avoidance gap D1 between the first side wall 131a and the mounting part 144, and the avoidance gap here is to reserve space for the movement of the mounting part 144, because when the shape memory alloy 20 is "stretched", the first wall 144a of the mounting part 144 will move in the direction of the first side wall 131a. In simple terms, the size of the first avoidance gap D1 when the shape memory alloy 20 is in the initial form CT is greater than the size of the first avoidance gap D1 when the shape memory alloy 20 is in the changed form BT.

[0054] Such a through hole 131 structure combined with the insertion of the mounting portion 144 is conducive to the completion of the abutment assembly of the two ends of the shape memory alloy 20. At the same time, the setting of the first avoidance gap D1 can make the entire motion structure more reasonable and ensure that the structure of the overall product is more stable.

[0055] like Fig.10 As shown, here, the upper surface of the lock buckle 13 has a circle of annular portion 132 around the through hole 131. In fact, it can be said that the hollow part of the annular portion 132 is also a part of the through hole 131. The design of the annular portion 132 is adopted so that the mounting portion 144 as a whole does not exceed the setting of the annular portion 132, so that the annular portion 132 can be used to protect the mounting position of the shape memory alloy 20 to a certain extent, and at the same time, the size of the mounting space of the shape memory alloy 20 is deformed.

[0056] like Figure 4 , Figure 5As shown, by setting such a shape memory alloy 20, the movable contact 30 and the conductive sheet 40 can be directly welded by soft connection, so that there will be only two welding points between the two, that is, no more than three. Of course, the conductive sheet 40 here can be an integral part or fixed by welding with the terminal plate of the second terminal. No matter which method is used, the structure using the above-mentioned shape memory alloy 20 will reduce the number of welding points and the risk of cold welding (because the more welding points, the greater the possibility of cold welding).

[0057] Through the above-mentioned method, the second terminal is electrically connected to the moving contact 30 .

[0058] 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 and connected in sequence. This connection method is common knowledge and will not be elaborated here.

[0059] That is to say, in this case, by connecting the first wiring terminal and the second wiring terminal to the external circuit, the small circuit breaker can be connected to the circuit to protect the circuit.

[0060] In the process of separation of the moving and static contacts, arcs are inevitable. In order to extinguish the arcs, the arc extinguishing chamber 100 is arranged near the moving and static contacts.

[0061] like Fig.16 As shown, the arc extinguishing chamber 100 comprises an arc extinguishing grid 110 and a bracket for fixing the arc extinguishing grid 110. In this embodiment, the bracket for fixing the arc extinguishing grid 110 is two side plates.

[0062] like Fig.16 As shown, there are fifteen arc-extinguishing grids 110, which are stacked in sequence along the first direction F1. From the figure of the circuit breaker, it can be seen 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 flat structure, the first direction F1 is the length direction. There is an interval between two adjacent arc-extinguishing grids 110. The interval here is the first interval 110a. In this embodiment, the number of the first intervals 110a is fourteen. Of course, the arc-extinguishing grids 110 here are not limited to fifteen pieces, as long as there are seven or more pieces.

[0063] like Fig.16As shown, the arc extinguishing chamber 100 includes a front end M1 and a rear end M2. The front end M1 here refers to the end of the arc extinguishing grid 110 facing the moving and static contacts, and this end has an arc extinguishing groove, allowing the arc to stretch here, so as to extinguish the arc. The rear end M2 here refers to the end away from the front end M1. Generally, as the arc is extinguished after breaking, some gas will be generated, and the gas will flow from the front end M1 to the rear end M2.

[0064] like Figure 1 , Figure 3 As shown, the circuit breaker housing 300 has a first air passage 310 and a second air passage 320. The first air passage 310 and the second air passage 320 are separated by a separation rib 330 on the circuit breaker housing 300. The separation rib 330 can be a component integrally formed with the circuit breaker housing 300, or can be separately formed and then mounted on the circuit breaker housing 300 by an assembly structure such as a snap-on connection.

[0065] like Figure 1 , Figure 3 As shown, before the arc gas enters the first gas channel 310 and the second gas channel 320, it will be divided by the partition, which is fixed at 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 partition, namely the first upper area S1, the first lower area S2, the second upper area S3 and the second lower area S4. The first upper area S1 and the second upper area S3 are both connected to the first gas channel 310, and the second upper area S3 and the second lower area S4 are both connected to the second gas channel 320.

[0066] like Fig.12 , Fig.13 As shown, specifically, the partition 200 has a first partition rib 210 and a second partition rib, and the first partition rib 210 and the second partition rib crisscross to divide the rear end M2 of the arc extinguishing chamber 100 into the above four areas. The first partition rib 210 here is equivalent to a longitudinal rib. The second partition rib includes a second sub-partition rib I 220 and a second sub-partition rib II 230, which are equivalent to two transverse ribs.

[0067] like Fig.12 , Fig.13 As shown, here, the second sub-partition ribs I 220 and the second sub-partition ribs II 230 are staggered, that is, the shape formed by the two is not a straight structure, but a Z-shaped structure. After such arrangement, the first upper area S1 and the first lower area S2 are formed by the first partition ribs 210 and the second sub-partition ribs I 220, and the first upper area S1 is smaller than the first lower area S2; the second upper area S3 and the second lower area S4 are formed by the first partition ribs 210 and the second sub-partition ribs II 230, and the second upper area S3 is larger than the second lower area S4.

[0068] like Fig.12 , Fig.13 As 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 first intervals 110a allocated to the first upper region S1 are less than the first intervals 110a allocated to the first lower region S2; the first intervals 110a allocated to the second upper region S3 are more than the first intervals 110a allocated to the second lower region S4. Of course, no matter how the first intervals 110a are divided, the number thereof in each region is not less than two.

[0069] like Fig.13 As shown, the partition 200 has an air-blocking portion 240 in each area, and the air-blocking portion 240 here blocks the rear end M2 of the first interval 110a. Of course, not all rear ends M2 of the first intervals 110a in each area are blocked by the air-blocking portion 240, but a part of the first intervals 110a are blocked by the air-blocking portion 240. Simply put, the total number of air-blocking portions 240 in each area is less than the total number of first intervals 110a. Such a structure can effectively increase the air pressure, accelerate the flow of gas, and enhance the arc extinguishing effect by blocking part of the first interval 110a. Of course, the air-blocking portion 240 here can only be said to block a part of the first interval 110a, because the first interval 110a generally spans two areas, and the air-blocking portion 240 in each area is bound to only block a part of the first interval 110a.

[0070] like Fig.13 As shown, here, the second sub-partition ribs I 220 and the second sub-partition ribs II 230 also bear the effect of part of the air blocking portion 240. That is, the second sub-partition ribs I 220 are located at the rear end M2 of a first interval 110a, shielding a part of it. The second sub-partition ribs II 230 are also located at the rear end M2 of a first interval 110a, shielding a part of it. The first interval 110a shielded by the second sub-partition ribs I 220 is not the same as the first interval 110a shielded by the second sub-partition ribs II 230. Here, the first interval 110a shielded by the second sub-partition ribs I 220 and the first interval 110a shielded by the second sub-partition ribs II 230 are two first intervals 110a that are closer to the middle part of the arc extinguishing chamber 100. Similarly, the second sub-partition ribs I 220 and II 230 here can only be said to block a portion of the first interval 110a. This is because the first interval 110a generally spans two areas, while the second sub-partition ribs I 220 and II 230 do not span two areas.

[0071] like Fig.13As shown, in general, the first interval 110a in which the rear end M2 of the first upper region S1 is blocked by the air blocking portion 240 is exposed in the second upper region S3. The first interval 110a in which the rear end M2 of the second upper region S3 is blocked by the air blocking portion 240 is exposed in the first upper region S1. The first interval 110a in which the rear end M2 of the first lower region S2 is blocked by the air blocking portion 240 is exposed in the second lower region S4. The first interval 110a in which the rear end M2 of the second lower region S4 is blocked by the air blocking portion 240 is exposed in the first lower region S2.

[0072] like Fig.15 As shown, here, in order to facilitate the assembly between the partition 200 and the arc extinguishing chamber 100, a rib 250 is provided on the air blocking portion 240, and the rib 250 is inserted into the first gap 110a to be shielded. In this way, the partition 200 and the arc extinguishing chamber 100 are equivalent to forming a plug-in fit, which is conducive to improving stability. Of course, there are many specific forms of the rib 250 here, such as a long strip or a convex point form.

[0073] like Fig.14 As 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, they are at a distance from the rear end M2, and all the air blocking portions 240 are bent and extended to the side of the arc extinguishing grid 110. The air blocking portions 240 of the first upper area S1 and the first lower area S2 and the second sub-partition ribs I 220 are connected by the first abutting ribs 260, and the first abutting ribs 260 are located beside the first side plate 205 and abut against the first side plate 205. The air blocking portions 240 of the second upper area S3 and the second lower area S4 and the second sub-partition ribs II 230 are connected by the second abutting ribs 270, and the second abutting ribs 270 are located beside the second side plate 215 and abut against the second side plate 215. The arrangement of the first abutting ribs 260 and the second abutting ribs 270 makes the strength of the partition 200 higher, and the side plates can also abut and cooperate.

[0074] like Figure 1 , Figure 3 As shown, the first air passage 310 and the second air passage 320 are separated by a separation rib 330 on the circuit breaker housing 300. Here, the separation rib 330 is also two staggeredly arranged to match the two staggered second sub-separation ribs I220 and second sub-separation ribs II230.

[0075] like Figure 1 , Figure 3 , Fig.17 as well as Fig.18As shown, the circuit breaker housing 300 is also formed with a first guide rib 340a, a second guide rib 340b, a third guide rib 340c and a fourth guide rib 340d. Here, the first guide rib 340a and the second guide rib 340b are both distributed in the first air duct 310, the first guide rib 340a is arranged at the rear end M2 of the first upper area S1, and the second guide rib 340b is arranged at the rear end M2 of the second upper area S3. The third guide rib 340c and the fourth guide rib 340d are both distributed in the second air duct 320, the third guide rib 340c is arranged at the rear end M2 of the first upper area S1, and the fourth guide rib 340d is arranged at the rear end M2 of the second lower area S4. The guide ribs correspond to the air blocking portion 240 in the corresponding area, so that the airflow can be guided by the guide ribs, which is conducive to controlling the flow direction of the gas.

[0076] like Figure 1 , Figure 3 , Fig.17 as well as Fig.18 As shown, here, the first guide rib 340a and the second guide rib 340b are both inclined upward, specifically, they are arranged inclined upward from the direction where the arc extinguishing structure is located to the direction away from the arc extinguishing structure, so that the gas from the first upper area S1 and the second upper area S3 can be guided to move upward.

[0077] like Figure 1 , Figure 3 , Fig.17 as well as Fig.18 As shown, here, the first guide rib 340a and the second guide rib 340b are arranged in a staggered manner. Such a staggered arrangement is more compatible with the corresponding air blocking portion 240, which is beneficial to the design of the gas flow channel.

[0078] like Figure 1 , Figure 3 , Fig.17 as well as Fig.18 As shown, here, the third guide rib 340c and the fourth guide rib 340d are both inclined downward, specifically, they are arranged to be inclined downward from the direction where the arc extinguishing structure is located to the direction away from the arc extinguishing structure, so as to guide the gas from the first lower area S2 and the second lower area S4 to move downward.

[0079] like Figure 1 , Figure 3 , Fig.17 as well as Fig.18 As shown, here, the third guide rib 340c and the fourth guide rib 340d are arranged in a staggered manner. Such a staggered arrangement is more compatible with the corresponding air blocking portion 240, which is beneficial to the design of the gas flow channel.

[0080] like Figure 1 , Figure 3As shown, finally, the gas passing through the first gas channel 310 is discharged through the first exhaust hole on the circuit breaker housing 300, and the gas passing through the second gas channel 320 is discharged through the second exhaust hole on the circuit breaker housing 300 or circulated to the front end M1 of the arc extinguishing chamber 100 through the internal circulating gas channel.

[0081] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction 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 may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without contradiction.

[0082] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A new type of miniature circuit breaker, comprising an operating mechanism, a moving contact, a stationary contact and a conductive sheet, wherein the operating mechanism comprises a contact support and a locking structure; the locking structure comprises a lock clasp and a pull rod assembly rotatably arranged on the contact support; the pull rod assembly and the lock clasp are in an unlocked state and a locked state, and the operating mechanism comprises a closed state and an open state; when the operating mechanism is in the closed state, the pull rod assembly and the lock clasp are in a locked state; when the operating mechanism is in the open state, the pull rod assembly and the lock clasp are in an unlocked state; the characteristics are: It also includes a shape memory alloy, one end of the shape memory alloy is against the contact support, and the other end is against the lock; the shape memory alloy has an initial shape and a changed shape; after the main line is overloaded, when the internal temperature of the small circuit breaker rises to the phase change temperature of the shape memory alloy, the shape memory alloy changes from the initial shape to the changed shape, and pushes the lock to rotate to unlock it from the pull rod assembly, causing the operating mechanism to trip.

2. A new type of miniature circuit breaker according to claim 1, characterized in that: A accommodating cavity is formed on the contact support, and a trigger opening is provided on one side of the accommodating cavity. A retaining wall is provided at the trigger opening where the lock is located. The shape memory alloy is installed in the accommodating cavity, with one end abutting against the retaining wall through the trigger opening, and the other end abutting against the cavity wall of the accommodating cavity. The shape memory alloy changes from an initial shape to a changed shape, and the lock rotates by pushing the retaining wall.

3. A new type of miniature circuit breaker according to claim 2, characterized in that: The contact support includes a main body and a mounting portion; the mounting portion is arranged on the upper surface of the main body, and the accommodating cavity is arranged in the mounting portion; The accommodating cavity also has an installation opening, which is arranged on the upper surface of the installation portion, and the shape memory alloy is loaded into the accommodating cavity from the installation portion.

4. A new type of miniature circuit breaker according to claim 3, 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 together form a accommodating cavity; the first wall is a side of the mounting portion close to the static contact, and the trigger opening is opened on a 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 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 accommodating cavity.

5. A new type of miniature circuit breaker according to claim 3, characterized in that: The mounting portion includes a first wall, a second wall and a third wall, which together with the main body form a receiving cavity; at least one of the first wall, the second wall and the third wall is provided with an anti-slip protrusion; the shape memory alloy is in the shape of a compression spring, and the anti-slip protrusion is abutted against the shape memory alloy to limit the shape memory alloy from escaping from the receiving cavity from the mounting opening.

6. A new type of miniature circuit breaker according to claim 3, characterized in that: The lock has a main body portion arranged on the upper surface of the contact support; a through hole is opened on the upper surface of the main body portion, and the mounting portion at least partially penetrates into the through hole; the through hole has a first side wall and a second side wall arranged opposite to each other, 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 of the shape memory alloy when the shape memory alloy is in the changed form.

7. A new type of miniature circuit breaker according to claim 6, characterized in that: The upper surface of the main body is provided with an annular portion, the hollow portion of the annular portion is also a part of the through hole, and the mounting portion does not exceed the hollow portion of the annular portion.

8. A novel miniature circuit breaker according to claim 1, characterized in that: The moving contact and the conductive sheet are connected via a soft connection, and the number of welding points between the three is less than three.

9. A novel miniature circuit breaker according to claim 1, characterized in that: The operating mechanism also 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 arranged on the contact support, and the locking state and unlocking state of the pull rod assembly and the buckle are realized by the buckle and the buckle; Alternatively, the operating mechanism also includes a handle, the pull rod assembly includes a pull rod, and the contact support is also a component of the locking structure. A first groove wall is provided on the contact support, and a second groove wall is provided on the lock buckle. One end of the pull rod is connected to the handle, and the other end of the pull rod extends into a matching groove formed by the first groove wall and the second groove wall. The relative angle between the lock buckle and the contact support changes, so that the gap between the first groove wall and the second groove wall changes, thereby realizing the locking and unlocking of the pull rod.

10. A new type of miniature circuit breaker according to any one of claims 1 to 9, characterized in that: It also includes a circuit breaker housing, an arc extinguishing chamber and a partition; the circuit breaker housing has an arc extinguishing chamber and a first air duct and a second air duct located at the rear of the arc extinguishing chamber; the arc extinguishing chamber and the partition are arranged in the arc extinguishing chamber, and the partition is fixed at the rear end of the arc extinguishing chamber; the partition 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 area, a first lower area, a second upper area and a second lower area; the first upper area and the second upper area are both connected to the first air duct, and the second upper area and the second lower area are both connected to the second air duct.

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