A miniature overload protector

Abstract

This application relates to the field of electrical safety technology, and in particular to a miniature overload protector. The miniature overload protector includes: a housing comprising a base and a top cover; the base has a recessed groove on its top surface, and the top cover is placed on the top surface and fixed to the base; a first end piece, one end of which passes through the housing and is located in the groove, abutting against the top cover; a second end piece, one end of which passes through the housing and is located in the groove, abutting against a side of the base opposite the top cover, wherein the first and second end pieces are connected at one end exposed in the housing and are used for connecting to an external circuit; a variable resistor, located in the groove, fixed to the second end piece and electrically conducting the second end piece; a third end piece, one end of which passes through the housing and is located in the groove, the other end of which is exposed in the housing for connecting to an external circuit, and is positioned opposite to the first end piece; and a deformable metal sheet, located in the groove, one end of which is connected to the third end piece, and the other end of which, depending on the state of the deformable metal sheet, abuts against the first end piece to conduct the circuit or abuts against the variable resistor to disconnect the circuit.

Description

Technical Field

[0001] This application relates to the field of electrical safety technology, and in particular to a miniature overload protector. Background Technology

[0002] With the popularization and development of electronic and electrical equipment, overload protectors are widely used as important safety components. Traditional overload protectors typically employ bimetallic strip or fuse structures, technologies that have developed into relatively mature industrial chains over a long period. In recent years, as electronic products have moved towards miniaturization and integration, higher demands have been placed on the size and performance of overload protectors. Existing miniature overload protectors on the market generally suffer from complex structures, numerous components, and difficult manufacturing processes, which directly affect product reliability and production costs.

[0003] Common miniature overload protector solutions currently include: a) a multi-layered composite bimetallic strip design, achieving rapid action through precise control of the metal strip's thickness and shape; b) a structure using precision-stamped metal springs in conjunction with thermistors; and c) a miniature fuse design employing surface mount technology (SMT). Among these, solution a offers fast response but is structurally complex; solution b has fewer components but requires extremely high precision in the metal spring molding, resulting in a low yield rate; and solution c, while small in size, lacks automatic reset functionality and requires replacement after use.

[0004] Therefore, how to design a product that can reduce the number of components used, simplify the manufacturing process, and maintain reliable overload protection performance is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] The purpose of this application is to overcome the above-mentioned technical problems and provide a miniature overload protector with a simplified structure, simple manufacturing process, and reliable overload protection performance.

[0006] This application discloses a miniature overload protector, which specifically adopts the following scheme:

[0007] A miniature overload protector includes: a housing comprising a base and a top cover, wherein the top surface of the base is recessed downwards and the top cover is disposed on the top surface and fixed to the base; a first end piece, one end of which passes through the housing and is located in the recess, and abuts against the top cover; a second end piece, one end of which passes through the housing and is located in the recess, and abuts against a side of the base opposite to the top cover, wherein the first end piece and the second end piece are connected at one end exposed in the housing and are used for connecting an external circuit; a variable resistor, located in the recess, fixed to the second end piece and electrically conducting the second end piece; a third end piece, one end of which passes through the housing and is located in the recess, and the other end of which is exposed in the housing for connecting an external circuit, and is disposed opposite to the first end piece; and a deformable metal sheet, located in the recess, one end of which is connected to the third end piece, and the other end abuts against the first end piece to conduct the circuit or abuts against the variable resistor to disconnect the circuit, depending on the state of the deformable metal sheet.

[0008] By adopting the above technical solution, the miniature overload protector uses a shell structure including a base and a top cover. The top surface of the base has a recessed groove, and the top cover is placed on and fixed to the base. This design can effectively protect internal components and avoid interference and damage from external factors. One end of the first and second end pieces passes through the shell and is located in the groove, respectively abutting against the side of the top cover and the base opposite to the top cover. The exposed ends are connected for external circuits, which can achieve a stable circuit connection. The variable resistor is fixed on the second end piece and is electrically conductive. It can change the resistance according to the current change, which can play a role in protecting the circuit. The third end piece is set opposite to the first end piece to ensure a reasonable current transmission path. One end of the deformable metal piece is connected to the third end piece, and the other end abuts against the first end piece to conduct the circuit or abuts against the variable resistor to disconnect the circuit according to the deformation. It can cut off the circuit in time when the circuit is overloaded to prevent the circuit from being damaged due to overload.

[0009] Optionally, the deformable metal sheet includes an initial state and a deformed state; wherein, in the initial state, the deformable metal sheet is an arc shape with a convex surface away from the upper cover, and one end abuts against the first end piece to conduct the circuit; in the deformed state, the deformable metal sheet is an arc shape with a convex surface close to the upper cover, and one end abuts against the variable resistor to disconnect the circuit.

[0010] By adopting the above technical solution, the miniature overload protector has the function of connecting and disconnecting the circuit. In the initial state, the deformable metal sheet abuts against the first end piece to make the circuit conduction, so that the equipment can work normally. When the current is too large, the deformable metal sheet changes from the initial state to the deformed state, and abuts against the variable resistor to disconnect the circuit, so as to play the role of overload protection and avoid the circuit from being damaged due to overload.

[0011] Optionally, the upper cover has a first slot on the side facing the groove for one end of the first end piece to abut; the base has a second slot for one end of the second end piece to abut.

[0012] By adopting the above technical solution, a first slot is provided on the side of the top cover facing the groove for one end of the first end piece to abut, which enables the first end piece to be accurately and stably positioned and installed on the top cover, ensuring the connection stability of the first end piece with other components, and thus ensuring the stability of the circuit connection; a second slot is provided on the base for one end of the second end piece to abut, which enables the second end piece to be accurately and stably installed on the base, improving the accuracy and stability of the second end piece installation, and thus helping to maintain the structural stability of the entire overload protector and the normal operation of the circuit; at the same time, the setting of the first slot and the second slot can also reduce the space occupied by the components and facilitate the miniaturization of the structure.

[0013] Optionally, the exposed end of the first end piece is bent and fitted to the base, and connected to the second end piece.

[0014] By adopting the above technical solution, the first end piece, which is bent and exposed, fits the base, making it easy to connect to the second end piece. This optimizes the external structural layout of the miniature overload protector and facilitates the connection of external circuits.

[0015] Optionally, the exposed end of the second end piece is bent to connect to the second end piece.

[0016] By adopting the above technical solution, both the exposed ends of the second end piece and the first end piece are bent, which facilitates the connection between the two and makes the appearance of the miniature overload protector more regular.

[0017] Optionally, the first end piece and the second end piece are laser-welded together at the ends exposed in the housing.

[0018] By adopting the above technical solution, laser welding can ensure the strong connection and good conductivity between the first and second end pieces, thereby improving the performance and stability of the miniature overload protector. At the same time, the high precision of laser welding can reduce the size of the welded area, which is beneficial for the miniaturization design of the miniature overload protector.

[0019] Optionally, the third end piece and the deformed metal sheet are welded together using a laser.

[0020] By adopting the above technical solution, the third end piece and the deformable metal piece are laser-welded, which can make the connection between the two firm and ensure good electrical conductivity, ensure stable current transmission, and improve the reliability and working stability of the entire miniature overload protector.

[0021] Optionally, the housing is made of insulating material, the deformable metal sheet is a bimetallic sheet, and the variable resistor is a PPTC or a ceramic PTC.

[0022] By adopting the above technical solutions, the use of an insulating housing can prevent leakage and ensure safe use; the use of a bimetallic strip as a deformation metal strip can utilize its thermal deformation characteristics to realize the circuit conduction and disconnection functions; the use of PPTC or ceramic PTC as a variable resistor can change the resistance to regulate the current and protect the circuit.

[0023] In summary, this application includes at least one of the following beneficial technical effects:

[0024] 1. The miniature overload protector consists of a housing, a first end piece, a second end piece, a variable resistor, a third end piece, and a deformable metal sheet. Compared with existing common solutions, this structural design reduces the number of product components, lowers the difficulty of the manufacturing process, improves product reliability, and reduces production costs.

[0025] 2. The circuit is turned on or off by deforming the metal sheet, without the need for a complex multi-layer composite structure or a metal spring sheet with extremely high forming precision, and can maintain reliable overload protection performance.

[0026] 3. The miniature overload protector has a simple and compact overall structure, which can meet the requirements of the miniaturization and integration of electronic products on the size and performance of overload protectors. Attached Figure Description

[0027] Figure 1 This is a three-dimensional structural diagram of a miniature overload protector disclosed in an embodiment of this application;

[0028] Figure 2 for Figure 1 A schematic diagram of the cross-sectional structure of a miniature overload protector in the conducting state;

[0029] Figure 3 for Figure 1 A schematic diagram of the cross-sectional structure of a miniature overload protector in the disconnected state.

[0030] Explanation of reference numerals in the attached figures:

[0031] 10. Housing; 11. Base; 111. Groove; 112. Second slot; 12. Top cover; 121. First slot; 20. First end piece; 30. Second end piece; 40. Variable resistor; 50. Third end piece; 60. Deformable metal sheet. Detailed Implementation

[0032] The terminology used in the following embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used in the specification and appended claims of this application, the singular expressions “a,” “an,” “the,” “the,” and “this” are intended to include the plural expressions as well, unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this application refers to and includes any or all possible combinations of one or more of the listed items.

[0033] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature, and in the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more.

[0034] The technical solutions of the embodiments of this application are described in detail below with reference to the accompanying drawings.

[0035] See Figure 1 and Figure 2 The miniature overload protector disclosed in this application includes a housing 10, a first end piece 20, a second end piece 30, a variable resistor 40, a third end piece 50, and a deformable metal sheet 60.

[0036] The housing 10 consists of a base 11 and a top cover 12. The top surface of the base 11 is recessed into a groove 111, and the top cover 12 is fixed to the top surface of the base 11 relative to the groove 111, thus providing space for protection and support of the internal components. One end piece 20 and the other end piece 30 pass through the housing 10 and are located in the groove 111, respectively abutting against one side of the top cover 12 and the side of the base 11 opposite to the top cover 12. Both are exposed at one end of the housing 10 and connected to an external circuit, thus enabling current conduction. A variable resistor is also included. 40 is located in the groove 111 and fixed on the second end piece 30, and is electrically connected to the second end piece 30; one end of the third end piece 50 passes through the housing 10 and is located in the groove 111, and the other end is exposed for external circuit connection and is set opposite to the first end piece 20, so as to realize the input and output of current; the deformable metal sheet 60 is located in the groove 111, one end is connected to the third end piece 50, and the other end can abut against the first end piece 20 to conduct the circuit or abut against the variable resistor 40 to disconnect the circuit, thereby realizing the function of overload protection.

[0037] Specifically, the base 11 and the top cover 12 of the housing 10 are both made of insulating material to prevent leakage and ensure safe use. The method of fixing the top cover 12 and the base 11 is not limited in this embodiment. It can be a snap-fit ​​connection, for example, with snaps on the edge of the top cover 12 and corresponding slots on the base 11, where the snaps engage with the slots to achieve fixation; or it can be glued together to firmly unite the top cover 12 and the base 11.

[0038] The upper cover 12 has a first slot 121 on its side facing the groove 111, for one end of the first end piece 20 to abut. The dimensions (length, width, and depth) of the first slot 121 are not limited here and can be designed based on the dimensions of the first end piece 20. The design of the first slot 121 can make the abutment of the first end piece 20 more stable and accurate, and improve space utilization. The base 11 has a second slot 112 on its side for one end of the second end piece 30 to abut. Similarly, the dimensions of the second slot 112 are not limited here and can be designed based on the dimensions of the second end piece 30. The design of the second slot 112 can ensure the stability of the abutment of the second end piece 30 and further improve space utilization.

[0039] One end of the first end piece 20 passes through the housing 10 and is located in the groove 111, abutting against the first slot 121. This arrangement of the first end piece 20 ensures tight contact with the upper cover 12. The end of the first end piece 20 exposed outside the housing 10 is bent and fits against the base 11, and is connected to the second end piece 30. The bent design facilitates connection with the second end piece 30 and better accommodates the connection requirements of external circuits. The ends of the first end piece 20 and the second end piece 30 exposed outside the housing 10 are connected by laser welding. Laser welding has the advantages of high welding strength and good welding precision, ensuring good electrical conductivity between the two.

[0040] One end of the second end piece 30 passes through the housing 10 and is located in the groove 111, abutting against the second slot 112. The exposed end of the second end piece 30 is also bent and connected to the bent portion of the first end piece 20. The bending of the second end piece 30 is also for the purpose of facilitating connection and adaptation to external circuits.

[0041] The variable resistor 40 is located in the groove 111, fixed to the second end piece 30, and electrically connected to the second end piece 30. The variable resistor 40 can be a PPTC (Polymer Positive Temperature Coefficient Thermistor), which has the characteristic of a sharp increase in resistance as the temperature rises; or it can be a ceramic PTC, which has a high Curie temperature and good stability. The variable resistor 40 is fixed to the second end piece 30 by welding or conductive adhesive, ensuring electrical continuity between the two.

[0042] One end of the third end piece 50 passes through the housing 10 and is located in the groove 111, while the other end is exposed outside the housing 10 for connecting to an external circuit, and is positioned opposite to the first end piece 20. The third end piece 50 and the deformable metal sheet 60 are connected by laser welding, so that the deformable metal sheet 60 can be stably connected to the third end piece 50, ensuring the continuity of the circuit.

[0043] The deformable metal sheet 60 is a bimetallic sheet composed of two metals with different coefficients of thermal expansion, which undergoes bending deformation upon temperature changes. This results in the deformable metal sheet 60 having both an initial state and a deformed state. See also Figure 2 This is the initial state of the deformable metal sheet 60. The deformable metal sheet 60 is an arc shape with a convex surface away from the upper cover 12, and one end abuts against the first end piece 20 to conduct the circuit. At this time, the entire miniature overload protector is in normal working condition, and current can flow smoothly. (See also...) Figure 3 When the circuit is overloaded, the current increases and the heat generated causes the deformable metal sheet 60 to change from its initial state to a deformed state, that is, from the initial arc shape to another convex arc shape close to the top cover 12, and one end abuts against the variable resistor 40. At this time, since the variable resistor 40 has a large resistance, it is equivalent to breaking the circuit, which plays the role of overload protection, and thus can well meet the usage requirements of the miniature overload protector.

[0044] In summary, the miniature overload protector disclosed in this application, through the housing 10 structure including a base 11 and a top cover 12, and the recessed groove 111 on the top surface of the base 11, with the top cover 12 covering and fixed on the base 11, can effectively protect internal components and avoid interference and damage from external factors; one end of the first end piece 20 and the second end piece 30 pass through the housing 10 and are located in the groove 111, respectively abutting against the side of the top cover 12 and the base 11 opposite to the top cover 12, and the exposed end is connected for external circuitry, enabling stable circuit connection; the variable resistor 40 is fixed on the second end piece 30 and electrically conductive, and can change its resistance according to the current change, thus protecting the circuit; the third end piece 50 is arranged opposite to the first end piece 20, ensuring a reasonable current transmission path; one end of the deformable metal sheet 60 is connected to the third end piece 50, and the other end abuts against the first end piece 20 to conduct the circuit or against the variable resistor 40 to disconnect the circuit according to the deformation, which can cut off the circuit in time when the circuit is overloaded, preventing the circuit from being damaged due to overload.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A miniature overload protector, characterized in that, include: The housing (10) includes a base (11) and a top cover (12). The top surface of the base (11) is recessed with a groove (111) and the top cover (12) is placed on the top surface and fixed to the base (11). The first end piece (20) passes through the housing (10) and is located in the groove (111), and abuts against the top cover (12). The second end piece (30) passes through the housing (10) and is located in the groove (111), and abuts against one side of the base (11) opposite to the upper cover (12). The first end piece (20) and the second end piece (30) are connected at one end exposed to the housing (10) and are used for external circuit connection. A variable resistor (40) is located in the groove (111), fixed on the second end piece (30), and electrically connected to the second end piece (30). The third end piece (50) has one end passing through the housing (10) and located in the groove (111), and the other end is exposed outside the housing (10) for external circuit connection, and is arranged opposite to the first end piece (20); The deformable metal sheet (60) is located in the groove (111), with one end connected to the third end piece (50) and the other end abutting against the first end piece (20) to conduct the circuit or abutting against the variable resistor (40) to disconnect the circuit, depending on the state of the deformable metal sheet (60).

2. The miniature overload protector according to claim 1, characterized in that, The deformable metal sheet (60) includes an initial state and a deformed state; In the initial state, the deformable metal sheet (60) is an arc shape with a convex surface away from the upper cover (12), and one end abuts against the first end piece (20) to conduct the circuit; in the deformed state, the deformable metal sheet (60) is an arc shape with a convex surface close to the upper cover (12), and one end abuts against the variable resistor (40) to disconnect the circuit.

3. The miniature overload protector according to claim 1, characterized in that, The upper cover (12) has a first slot (121) on the side facing the groove (111) for one end of the first end piece (20) to abut. The base (11) is provided with a second slot (112) for one end of the second end piece (30) to abut.

4. The miniature overload protector according to claim 1, characterized in that, The exposed end of the first end piece (20) is bent and fits against the base (11), and is connected to the second end piece (30).

5. The miniature overload protector according to claim 4, characterized in that, The exposed end of the second end piece (30) is bent and connected to the second end piece (30).

6. The miniature overload protector according to claim 1, characterized in that, The first end piece (20) and the second end piece (30) are laser-welded together at the ends of the housing (10) that are exposed outside the housing (10).

7. The miniature overload protector according to claim 1, characterized in that, The third end piece (50) and the deformable metal piece (60) are welded together by laser.

8. The miniature overload protector according to claim 1, characterized in that, The housing (10) is made of insulating material, the deformable metal sheet (60) is a bimetallic sheet, and the variable resistor (40) is PPTC or ceramic PTC.

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