A temperature fuse suitable for use in a heater

Abstract

The utility model relates to temperature fuse technical field, especially in kind suitable for heater's temperature fuse. The temperature fuse includes temperature fuse device, high pressure cut -out device, shell, apron and two pins, the shell and apron form the internal cavity in common, this cavity is divided into temperature fuse device cavity and high pressure cut -out device cavity, and two devices are contained in the corresponding cavity respectively and are parallelly connected between two pins. The pin is equipped with the bending part, and can be directly attached and welded to the corresponding soldering pad of the surface of the ceramic heater during installation. The design is adapted to the arc surface of the cylindrical ceramic heater, improves the heat conduction efficiency and response speed, guarantees the high pressure breaking safety at the same time, realizes reliable over -temperature protection.

Description

Technical Field

[0001] This utility model relates to the field of temperature fuse technology, and in particular to a temperature fuse suitable for heaters. Background Technology

[0002] Thermal fuses, as over-temperature protection components, are widely used in various electric heating equipment to promptly cut off the circuit when the equipment temperature rises abnormally, preventing overheating damage or safety accidents. In high-temperature operating environments such as ceramic heaters, higher requirements are placed on the response speed, voltage withstand capability, and structural adaptability of thermal fuses.

[0003] Most common temperature fuses on the market currently employ axial or radial lead structures, with epoxy resin or ceramic housings as the primary encapsulation method. Their installation methods are typically planar bonding or lead plug-in. When these fuses are applied to cylindrical heaters, the curved surface of the heater makes it difficult to achieve a full fit with the planar mounting surface of traditional fuses. Furthermore, the temperature fuse does not directly contact the heating element of the heater, resulting in low heat transfer efficiency, delayed response, and affecting the timeliness of protection.

[0004] Furthermore, existing thermal fuses have limitations in high-voltage breaking capacity, especially when they melt at higher operating voltages, they are prone to arcing, leading to breaking failure or secondary short circuits. Although some products have attempted to incorporate arc-quenching materials, they are often complex in structure and large in size, making them difficult to install and use inside ceramic heaters with high miniaturization requirements.

[0005] Therefore, existing technologies lack a temperature fuse that can simultaneously meet the requirements of small size, high-voltage interruption, high response speed, and close contact with the curved surface of a cylindrical heater. This application is proposed against this background, aiming to solve the aforementioned comprehensive technical problems. Utility Model Content

[0006] To overcome the shortcomings of the prior art, this utility model provides a temperature fuse suitable for heaters, including a temperature fusing device, a high-voltage cutting device, a shell and cover plate that together form an internal cavity, and two pins; The temperature-induced fuse and the high-voltage cutoff device are connected in parallel in the internal cavity; after being connected in parallel, the temperature-induced fuse and the high-voltage cutoff device are soldered to the corresponding pads on the surface of the heater through two pins; the pads are electrically connected to the heating wire of the heater.

[0007] Furthermore, the temperature-sensitive fuse includes a temperature-sensing element, and the high-voltage cutting-off device includes a fuse wire. The temperature-sensing element and the fuse wire are respectively welded to the two pins to form the parallel circuit.

[0008] Furthermore, the temperature-induced fuse also includes a fusing agent filled within its cavity.

[0009] Furthermore, the high-voltage cutting-off device also includes an arc-extinguishing medium filled in its cavity.

[0010] Furthermore, the temperature fuse has an arc-shaped mounting surface for fitting against the outer surface of the heater, which is a cylindrical heater.

[0011] Furthermore, the pin is configured to have a bend, which allows the solder end to directly contact the pad during installation.

[0012] Furthermore, the cover plate and the outer shell are connected by a hook and a hole.

[0013] Furthermore, the two pins are fixed in one or more injection molded bodies, which are housed inside the outer shell; the injection molded body is provided with the locking hole, and the cover plate is provided with the locking hook, which is used to fix the pins by engaging with the locking hole.

[0014] Furthermore, the card hole has a through hole; the hook is block-shaped, and its cross-sectional shape is adapted to the through hole so as to pass through the through hole, and the hook and the card hole are interference fit.

[0015] Furthermore, the internal cavity is divided into a temperature-controlled fuse chamber and a high-voltage cut-off chamber; The temperature-sensitive fuse is housed within the temperature-sensitive fuse cavity and electrically connected between the two pins; the high-voltage cut-off device is housed within the high-voltage cut-off cavity and electrically connected between the two pins.

[0016] Furthermore, the outer shell and cover are made of ceramic or high-temperature resistant plastic.

[0017] Compared with the prior art, the temperature fuse for ceramic heaters provided by this utility model has the following advantages: The temperature fuse and the high-voltage cutoff device are connected in parallel between the two pins. When the ceramic heater overheats, the temperature fuse responds first, and then the high-voltage cutoff device breaks the circuit, balancing the timeliness of overheat protection and the safety of high-voltage disconnection. The pads are electrically connected to the heating wire of the ceramic heater, and the heat from the heater is directly conducted to the temperature fuse connected to the pads, improving heat transfer efficiency. The pins are soldered to the corresponding pads of the ceramic heater, which not only meets the installation requirements of the ceramic heater, but also creates a direct contact heat conduction path from the heater to the internal fuse, improving the temperature response speed. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic diagram of the installation structure of the temperature fuse and ceramic heater provided by this utility model; Figure 2 A schematic diagram showing the connection relationship between the temperature fuse, ceramic heater, and power supply provided by this utility model; Figure 3 A schematic diagram of the circuit principle of the temperature fuse provided by this utility model; Figure 4 A schematic diagram of the overall structure of the temperature fuse provided by this utility model; Figure 5 An exploded perspective view of the temperature fuse provided in Embodiment 1 of this utility model; Figure 6 A schematic diagram showing the completed packaging of the temperature fuse according to Embodiment 1 of this utility model; Figure 7 An exploded three-dimensional view of the temperature fuse of Embodiment 2 provided by this utility model.

[0020] Figure label: 10-Cover plate; 11-Shell; 12-Pin; 13-Pin a; 14-Pin b; 15-Temperature fuse; 16-High voltage cut-off device; 17-Temperature fuse cavity; 18-High voltage cut-off device cavity; 19-Temperature sensor; 20-Fuse wire; 21-Pad; 22-Pad a; 23-Pad b; 24-Pad c; 25-Hook; 26-First hook; 27-Second hook; 28-Hook hole; 29-First hook hole; 30-Second hook hole; 31-Injection body; 32-Injection body a; 33-Injection body b; 34-Injection body c; 35-Ceramic heater; 36-Ceramic heater heating wire; 37-Outer pin. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0022] In the description of this utility model, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this utility model. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] This invention provides a temperature fuse suitable for cylindrical heaters, which achieves direct and close contact with the arc-shaped surface of the heater, thereby achieving rapid heat conduction and efficient and reliable over-temperature protection.

[0024] like Figure 1-7 As shown, the thermal fuse mainly includes a housing 11, a cover plate 10, two leads 12, a thermal fusing device 15, and a high-voltage cut-off device 16, as follows: Figure 4 As shown, the outer shell 11 and the cover plate 10 together form an internal cavity, which is divided into a temperature fuse device cavity 17 and a high voltage cut-off device cavity 18. The temperature fuse device 15 is housed in its cavity, and the high voltage cut-off device 16 is housed in its cavity. The two devices are directly connected in parallel through pin 12. The pin 12 is configured to have a bent portion for direct contact with the solder end during installation, and further, the bent portion of the pin 12 can be made to have the same contact surface shape as the solder pad 21 on the arc-shaped mounting surface of the thermal fuse body.

[0025] As attached Figure 1 and 2 As shown, this invention preferably uses a ceramic heater. During installation, the welding end is directly attached to and welded to the pad 21 on the surface of the ceramic heater 35. The two pins are specifically pin a 13 and pin b 14. One end of pin a 13 and pin b 14 can be directly welded to pad c 24 and pad b 23 on the mounting surface, respectively. Pad b 23 and pad a 22 are directly welded to the heating wire 36 of the ceramic heater. The other end of pin a 13 and pin b 14 is welded to the temperature-breaking device 15. Because the pad 21 is directly connected to the heating wire of the ceramic heater 35, heat can be directly and quickly conducted from the heating wire through the pad 21 and pin 12 to the temperature-breaking device 15, achieving an extremely high thermal response speed. Figure 3The diagram shows the circuit schematic. Current enters from external pin 37, passes through heating wire 36 and pad 21, flows to pin 12 and enters the temperature-controlled fuse 15. After the temperature-controlled fuse 15 melts, the current flows to the high-voltage cutoff device 16, and finally exits through pin 12 from another external pin 37. By directly connecting the heater to the circuit, both active cutoff and significantly improved heat transfer efficiency can be achieved. During normal circuit operation, the current does not pass through the high-voltage cutoff device 16. The current flow direction is: external pin 37 → pad a 22 → ceramic heater heating wire 36 → pad b 23 → pin b14 → temperature-controlled fuse 15 → pin a 13 → external pin 37. When the temperature-controlled fuse 15 melts, the current flows to the high-voltage cutoff device 16. Of course, the current flow direction can be designed according to actual needs; this design does not impose excessive limitations.

[0026] Preferably, the shape of the pin 12 is set to be the same as the outer surface of the contact portion of the ceramic heater 35, which improves stability and further ensures heat transfer efficiency.

[0027] Based on the above scheme, the temperature fuse device 15 further includes a temperature sensor 19, and the high-voltage cutoff device 16 includes a fuse 20. The temperature sensor 19 and the fuse 20 are respectively welded to the two pins 12 to form the parallel circuit. By forming a parallel circuit by welding the temperature sensor 19 and the fuse 20 to the pins 12, the temperature sensor 19 can be triggered first when the temperature is too high, and then the fuse 20 can complete the high-voltage cutoff, thus taking into account both the timeliness of the over-temperature response and the safety of the high-voltage cutoff.

[0028] Based on the above scheme, the temperature fuse device 15 further includes a fusing agent filled in its cavity. The fusing agent can assist the temperature sensing element 19 to melt and shrink quickly when it reaches the melting point, avoid protection delay, and improve the over-temperature protection response efficiency.

[0029] Based on the above scheme, the high-voltage cutting device 16 further includes an arc-extinguishing medium filled in its cavity. The arc-extinguishing medium is preferably arc-extinguishing paste. The arc-extinguishing paste can quickly extinguish the arc when the fuse 20 breaks the circuit, prevent arc breakdown or secondary short circuit, and improve the reliability of high-voltage cutting.

[0030] Building upon the aforementioned design, the temperature fuse further comprises an arc-shaped mounting surface for contacting and mounting with the outer surface of the cylindrical ceramic heater 35. This arc-shaped mounting surface adapts to the outer surface of the cylindrical ceramic heater 35, ensuring a tight fit and direct heat transfer to the internal components, thus improving the heat transfer rate. More preferably, the lead 12 of the temperature fuse is an arc-shaped structure with concentric circles of the cylindrical ceramic heater 35. This allows the lead 12 to fit even closer to the cylindrical ceramic heater 35, absorbing heat conducted from the insulation portion of the cylindrical ceramic heater 35, and simultaneously absorbing heat directly transferred from the heating wire 36 of the ceramic heater, ensuring efficient heat transfer.

[0031] Based on the above solution, the cover plate 10 and the outer shell 11 are further fixed by epoxy resin encapsulation, which can fill the gap between them to achieve sealing protection and prevent dust and moisture from entering the internal cavity.

[0032] Based on the above solution, the cover plate 10 and the outer shell 11 are further connected by a hook 25 and a hole 28. The connection between the hook 25 and the hole 28 does not require resin filling and curing processes, thus simplifying the assembly process.

[0033] Based on the above scheme, further, the two pins 12 are fixed in one or more injection molded bodies 31 by injection molding process, and the injection molded body 31 is housed inside the outer shell 11; the injection molded body 31 is provided with the locking hole 28, and the cover plate 10 is provided with the locking hook 25, and the fixing is achieved by the cooperation of the locking hook 25 and the locking hole 28.

[0034] By adopting the above solution, the positioning accuracy of pin 12 is guaranteed to ensure welding quality, and the injection molding body 31 provides a locking hole 28 to cooperate with the locking hook 25, which takes into account the insulation protection of pin 12 and the fixation of cover plate 10, thereby improving structural stability.

[0035] Based on the above solution, the locking holes 28 further include a first locking hole 29 and a second locking hole 30 formed on the two outer injection molded bodies 31; the hooks 25 on the cover plate 10 include a first hook 26 that cooperates with the first locking hole 29 and a second hook 27 that cooperates with the second locking hole 30. The locking holes 28 of the two outer injection molded bodies 31 cooperate with the corresponding hooks 25 of the cover plate 10 to form a double-point fixation, which strengthens the connection stability between the cover plate 10 and the injection molded body 31, avoids loosening during use, and improves the overall structural reliability.

[0036] The locking hole 28 is shaped like a "door," with a through hole in the middle for the hook 25 to pass through. The hook 25 is a trapezoidal block shape, facilitating its passage through the through hole of the locking hole 28. The hook 25 and the locking hole 28 are interference-fitted. More preferably, a protrusion or barb can be provided at the end of the hook 25, which abuts against the outer wall of the locking hole 28 after passing through the through hole, thereby achieving limiting and fixing.

[0037] The shape of the card hole is not limited to the "door" shape, but can be the "return" shape, rounded rectangle, ellipse or any other closed ring structure that can form a complete peripheral wall for the hook to pass through and lock.

[0038] The shape of the hook is not limited to trapezoidal; it can be wedge-shaped, cylindrical (to match the circular card hole), or any shape with a guide bevel, as long as it is easy to insert and pass through the card hole.

[0039] Based on the above solution, the outer shell 11 and the cover plate 10 are further made of ceramic or high-temperature resistant plastic.

[0040] This utility model provides two main assembly implementation methods, Embodiment 1 and Embodiment 2, as detailed below: Example 1 See Figure 5 and Figure 6 This embodiment provides a thermal fuse.

[0041] The thermal fuse includes a ceramic housing 11 and a ceramic cover plate 10, which together enclose an internal cavity, which is divided into a thermal fuse chamber 17 and a high-voltage cut-off chamber 18.

[0042] Two pins 12 are partially disposed inside the housing 11 and extend to the outside as connection terminals. Inside the temperature-sensitive fuse chamber 17, a temperature-sensing element 19 is directly soldered between the two pins 12, forming the temperature-sensitive fuse 15, and this chamber is filled with fluxing agent. Inside the high-voltage cutoff chamber 18, a fuse 20 is directly soldered between the two pins 12, forming the high-voltage cutoff device 16, and this chamber is filled with arc-quenching paste. Thus, the temperature-sensitive fuse 15 and the high-voltage cutoff device 16 form a parallel circuit through the two pins 12.

[0043] The body of the thermal fuse has an arc-shaped mounting surface. The two pins 12 have specific bends that allow the soldered ends to directly contact the solder pads 21 during installation.

[0044] During assembly, after placing each component inside the housing 11, epoxy resin is used to seal and fix the cover plate 10 to the housing 11 together to form a sealed structure.

[0045] During installation, such as Figure 1 and Figure 2As shown, the arc-shaped mounting surface of the thermal fuse is attached to the surface of the cylindrical ceramic heater 35, and the soldering ends of the two pins 12 are directly soldered to the corresponding pads 21 on the surface of the heater. The pads 21 are directly connected to the heating wire of the heater, thereby establishing a direct heat conduction path from the heat source to the thermal fuse pins 12.

[0046] In use, when the heater overheats abnormally, the heat is directly and rapidly conducted to the pin 12 through the pad 21, quickly raising the temperature of the sensing element 19. When the temperature reaches the melting point of the sensing element 19, it melts and contracts with the aid of the flux, disconnecting the current in this circuit. All the current is then transferred to the parallel fuse 20, which melts instantly and effectively extinguishes the arc with the help of the arc-extinguishing paste, ultimately safely and reliably cutting off the entire circuit.

[0047] Example 2 See Figure 7 This embodiment is an optimization and improvement of the assembly process in Embodiment 1.

[0048] The temperature fuse in this embodiment has the same functional components as in Embodiment 1, including the temperature sensor 19, fuse wire 20, flux, arc extinguishing paste, and parallel circuit structure. The main difference lies in the internal support structure and the way the cover plate 10 is fixed.

[0049] Specifically, the two pins 12 are first pre-fixed in three independent injection molded bodies 31 (injection body a 32, injection body b 33, and injection body c 34) by injection molding. Among them, the two outer injection bodies a 32 and injection body c 34 are respectively formed with a first locking hole 29 and a second locking hole 30.

[0050] During assembly, pins a13 and b14 are first pre-molded into the injection molded body 31, followed by soldering the temperature sensor 19 and the fuse 20. Then, the cover plate 10 is placed on top, on which a first hook 26 and a second hook 27 are formed, corresponding to the positions of the first locking hole 29 and the second locking hole 30. By pressing, the first hook 26 engages with the first locking hole 29, and the second hook 27 engages with the second locking hole 30, thereby achieving a firm mechanical connection between the cover plate 10 and the outer shell 11. This eliminates the need for the dispensing and curing processes required for epoxy resin encapsulation, improving assembly efficiency.

[0051] This embodiment also features an arc-shaped mounting surface and bent pins 12, enabling it to achieve the same direct heat conduction and over-temperature protection functions as Embodiment 1.

[0052] Although this document frequently uses terms such as housing, cover plate, two pins, temperature fuse, and high-voltage cutoff device, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of this invention; interpreting them as any additional limitation would contradict the spirit of this invention.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model 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 or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A temperature fuse suitable for heaters, characterized in that: It includes a temperature fuse (15), a high-voltage cut-off device (16), a housing (11) and a cover plate (10) that together form an internal cavity, and two pins (12). The temperature fuse (15) and the high voltage cut-off device (16) are connected in parallel in the internal cavity; after the temperature fuse (15) and the high voltage cut-off device (16) are connected in parallel, they are soldered to the corresponding pad (21) on the surface of the heater (35) through two pins (12); the pad (21) is electrically connected to the heating wire of the heater.

2. The thermal fuse according to claim 1, characterized in that: The temperature-sensitive fuse (15) includes a temperature sensor (19), and the high-voltage cut-off device (16) includes a fuse (20). The temperature sensor (19) and the fuse (20) are respectively welded to the two pins (12).

3. The thermal fuse according to claim 1, characterized in that: The temperature-controlled fuse (15) also includes a fusing agent filled in its cavity.

4. The thermal fuse according to claim 1, characterized in that: The high-voltage cutting device (16) also includes an arc-extinguishing medium filled in its cavity.

5. The thermal fuse according to claim 1, characterized in that: The temperature fuse has an arc-shaped mounting surface for fitting against the outer surface of the heater (35), which is a cylindrical heater.

6. The thermal fuse according to claim 5, characterized in that: The pin (12) is configured to have a bend for direct contact of the solder end with the pad (21) during installation.

7. The thermal fuse according to claim 1, characterized in that: The cover plate (10) and the outer shell (11) are connected by a hook (25) and a hole (28).

8. The thermal fuse according to claim 7, characterized in that: The two pins (12) are fixed in one or more injection molded bodies (31), which are housed inside the outer shell (11); the injection molded body (31) is provided with the card hole (28), and the cover plate (10) is provided with the hook (25), which is fixed by the cooperation of the hook (25) and the card hole (28).

9. The thermal fuse according to claim 8, characterized in that: The card hole (28) is provided with a through hole; the hook (25) is block-shaped and its cross-sectional shape is adapted to the through hole so as to pass through the through hole, and the hook (25) and the card hole (28) are interference fit.

10. The thermal fuse according to claim 1, characterized in that: The internal cavity is divided into a temperature fuse chamber (17) and a high-voltage cut-off chamber (18). The temperature fuse (15) is housed in the temperature fuse cavity (17) and electrically connected between the two pins (12); the high voltage cut-off device (16) is housed in the high voltage cut-off cavity (18) and electrically connected between the two pins (12).

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