Quick-response thermal fuse
By combining a bimetallic strip and an electrical disconnecting device, a fast-response thermal fuse was designed, which solves the problems of slow response speed and contact adhesion in the prior art. It achieves fast response, high breaking voltage and stable operating temperature, thus improving product performance.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- XIAMEN SET ELECTRONICS CO LTD
- Filing Date
- 2025-10-20
- Publication Date
- 2026-07-02
AI Technical Summary
In the existing technology, bimetallic sheet mechanical structures and low-melting-point alloys each have their own advantages and disadvantages in the field of thermal protection. They cannot meet the requirements of fast response and high breaking current and voltage, and are prone to problems such as contact adhesion and susceptibility to ambient temperature.
A fast-response temperature fuse was designed, which combines a bimetallic strip and an electrical disconnect device. Through the cooperation of the tripping device and the electrical disconnect device, a fast response and a high breaking voltage are achieved. A high-voltage circuit disconnect device is used to ensure one-time disconnection and avoid contact sticking.
It achieves rapid response, stable operating temperature, high breaking voltage capability, small size and resistance to high and low temperature shocks, and does not require epoxy resin encapsulation, thus improving user experience and product performance.
Smart Images
Figure CN2025128767_02072026_PF_FP_ABST
Abstract
Description
A fast-response thermal fuse
[0001] This application claims priority to Chinese Patent Application No. 202411911136.8, filed on December 24, 2024, entitled "A Fast-Response Temperature Fuse", the entire contents of which are incorporated herein by reference. Technical Field
[0002] This disclosure relates to the field of thermal fuses, and more particularly to a fast-response thermal fuse. Background Technology
[0003] Currently, in the field of thermal protection, the main technical approaches are the mechanical structure of bimetallic strips and the specific physical melting point of low-melting-point alloys. Each approach has its own advantages and disadvantages in practical applications.
[0004] The advantages of bimetallic fuses are: fast response speed; high and stable operating temperature accuracy; and adjustable operating temperature through size and material. The disadvantages are: A) they are larger in size compared to low-melting-point alloy thermal fuses; B) they have lower current and voltage breaking capacity, typically breaking voltage ≤250AC and current ≤20A; C) due to temperature-dependent, periodic opening and closing, contacts are easily welded together by current, making them unable to disconnect.
[0005] Low-melting-point alloys have specific physical melting points, and their advantages include: high breaking current and voltage capacity, up to 1500VDC; high and stable operating temperature accuracy; operating temperature can be adjusted by size and material; smaller size compared to the mechanical structure of bimetallic strips; and one-time operation without contact adhesion. Their disadvantages include: A) relatively slow response speed; B) large difference between operating temperature and holding temperature, exceeding 20℃; C) susceptibility to deformation due to ambient temperature; and D) the need for epoxy resin encapsulation.
[0006] In practical market applications, as heater power increases, the heating rate is much higher than that of existing heaters, and the requirements for protection response speed are becoming increasingly urgent. At the same time, there is a growing demand to integrate the advantages of the two technologies, so as to combine their strengths and overcome their weaknesses in order to better meet customer needs.
[0007] Overview
[0008] This disclosure aims to provide a fast-response temperature fuse to address the challenge of integrating the advantages of both the mechanical structure of bimetallic strips and the specific physical melting point of low-melting-point alloys in the field of thermal protection.
[0009] The technical solution is as follows:
[0010] A fast-response temperature fuse includes a housing, a bimetallic strip disposed in the housing, a tripping device, a first electrode, a second electrode, and an electrical disconnecting device bridging the first electrode and the second electrode.
[0011] The two ends of the tripping device abut against the movable end of the bimetallic strip and the electrical disconnecting device, respectively; the bimetallic strip is close to the housing; when the bimetallic strip is heated and deformed, it pushes the tripping device and the electrical disconnecting device to disengage from the abutment state;
[0012] The electrical disconnect device remains in a conductive state under the external force applied by the tripping device, and is in a disconnected state when the external force is removed.
[0013] In at least one embodiment, the electrical disconnection device includes a contact and a spring, the contact and the spring being disposed on the first electrode and the second electrode respectively. When an external force is applied, the spring abuts against the contact, causing the electrical disconnection device to be in a conductive state. When the external force is removed, the spring moves away from the contact under its elastic force, causing the electrical disconnection device to be in a disconnected state.
[0014] In at least one embodiment, the tripping device includes a base, a limiting block, a push rod, and an elastic element; the push rod has a groove; the limiting block is a plate-like structure with a through hole; one end of the limiting block abuts against the movable end of the bimetallic strip, serving as the operating end of the tripping device; one end of the push rod passes through the through hole, causing the groove and the through hole to engage; the elastic element is disposed between the limiting block and the base, and is used to apply a force to the limiting block in the direction of the bimetallic strip, keeping the limiting block and the movable end of the bimetallic strip in abutment, and keeping the groove and the through hole engaged; the other end face of the push rod abuts against the electrical disconnecting device, keeping the electrical disconnecting device in a conductive state; when the tripping device is activated, the movable end of the bimetallic strip pushes the limiting block to move away from the bimetallic strip, causing the groove and the through hole to disengage, and the push rod moves away from the electrical disconnecting device under the reverse force of the electrical disconnecting device.
[0015] In at least one embodiment, the tripping device includes a swing arm, a base, a limiting rod, a push rod, and an elastic element; the swing arm is the operating end of the tripping device; the base is provided with a first through groove for limiting the limiting rod to move back and forth in a first direction; the base is provided with a second through groove or a second cavity is provided outside the base for limiting the push rod to move back and forth in a second direction; the first direction and the second direction are perpendicular; the push rod is the tripping end of the tripping device; the movement directions of the swing arm and the limiting rod are perpendicular, and the movement directions of the limiting rod and the push rod are perpendicular; one end of the swing arm abuts against the movable end of the bimetallic strip, and the other end abuts against one end of the limiting rod; the other end of the limiting rod extends out of the base and abuts against one end of the push rod; the end face of the other end of the push rod abuts against the electrical disconnecting device; the elastic element is used to apply a force toward the swing arm to the limiting rod.
[0016] In at least one embodiment, one end of the limiting rod is provided with a limiting cap with a diameter larger than that of the first through groove, the first through groove is a stepped through groove, one end of the elastic member abuts against the inner side of the limiting cap, and the other end abuts against the step of the stepped through groove.
[0017] In at least one embodiment, the swing arm is provided with an arc-shaped clearance groove.
[0018] In at least one embodiment, the tripping device includes a base, a swing arm, a limiting block, a push rod, and an elastic element; the swing arm is the operating end of the tripping device; the base is provided with a first through groove for limiting the push rod to move back and forth in a first direction, and a second through groove for limiting the limiting block to move back and forth in a second direction, the first direction and the second direction being perpendicular; the push rod is the tripping end of the tripping device; the base is provided with a fulcrum for the swing arm to swing, and the middle part of the swing arm abuts against the fulcrum; one end of the limiting block is provided with a limiting step; one end of the swing arm abuts against the movable end of the bimetallic strip, and the other end abuts against the inner side of the limiting step; the other end of the limiting block abuts against one end of the push rod in the first through groove, and the other end of the push rod extends out of the base and abuts against the electrical disconnecting device; the elastic element is used to apply a force toward the limiting block to the push rod.
[0019] In at least one embodiment, the first through groove is a stepped through groove, one end of the elastic member abuts against the inner side of the limiting cap, and the other end abuts against the junction of the stepped through groove.
[0020] In at least one embodiment, the housing includes a cover plate, an outer shell, and a base plate, wherein the base plate is a heat-conducting plate, and before thermal deformation, the movable end of the bimetallic strip overlaps with the base plate; after thermal deformation, the movable end of the bimetallic strip disengages from the base plate.
[0021] In at least one embodiment, a high-voltage circuit breaking device is further included, the high-voltage circuit breaking device comprising a fuse, or a fuse connected in series with a low-melting-point alloy, the two ends of the high-voltage circuit breaking device being respectively connected to the first electrode and the second electrode.
[0022] Technical effects:
[0023] The fast-response temperature fuse disclosed herein integrates the advantages of both current bimetallic strip and low-melting-point alloy technologies, while overcoming the disadvantages of both technologies, thus improving the user experience and significantly enhancing product performance.
[0024] The above description is merely an overview of the technical solution disclosed herein. In order to better understand the technical means of this disclosure and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this disclosure more apparent and understandable, specific embodiments of this disclosure are described below.
[0025] Brief description of the attached diagram
[0026] To more clearly illustrate the technical solutions in the embodiments of this disclosure 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 disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0027] Figure 1 schematically shows a circuit block diagram of the fast-response thermal fuse of this disclosure;
[0028] Figure 2 schematically shows an exploded view of a first embodiment of the fast-response thermal fuse of this disclosure;
[0029] Figure 3 schematically shows a diagram of the non-tripped state of a first embodiment of the fast-response thermal fuse of this disclosure;
[0030] Figure 4 schematically illustrates the tripping state of a first embodiment of the fast-response thermal fuse of this disclosure;
[0031] Figure 5 schematically shows an exploded view of a second embodiment of the fast-response thermal fuse of this disclosure;
[0032] Figure 6 schematically shows a second embodiment of the fast-response thermal fuse of this disclosure in the non-tripped state;
[0033] Figure 7 schematically illustrates the tripping state of a second embodiment of the fast-response thermal fuse of this disclosure;
[0034] Figure 8 schematically shows an exploded view of a third embodiment of the fast-response thermal fuse of this disclosure;
[0035] Figure 9 schematically illustrates the non-tripped state of a third embodiment of the fast-response thermal fuse of this disclosure;
[0036] Figure 10 schematically illustrates the tripping state of a third embodiment of the fast-response thermal fuse of this disclosure.
[0037] Detailed description
[0038] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.
[0039] To further illustrate the various embodiments, this disclosure provides accompanying drawings. These drawings are part of the disclosure and are primarily used to illustrate the embodiments, and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementations and the advantages of this disclosure. Components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.
[0040] The present disclosure will now be further described in conjunction with the accompanying drawings and specific embodiments.
[0041] As shown in Figure 1, this disclosure provides a fast-response temperature fuse, including a housing assembly 10 and a protection triggering device 20, a circuit current-carrying device 30 and a circuit high-voltage disconnecting device 30 disposed in the housing assembly 10.
[0042] The protection triggering device 20 includes a bimetallic strip 21 and a tripping device 22, etc. The two ends of the tripping device 22 abut against the bimetallic strip 21 and the circuit current-carrying device 30, respectively. The bimetallic strip 21 directly contacts the heat source through the housing assembly 10. When the bimetallic strip 21 warps and deforms due to heat, it will act on the tripping device 22, causing the tripping device 22 to activate.
[0043] The circuit current-carrying device 30 includes two electrode plates 31 and 32 and an electrical disconnecting device 33 connecting the two electrode plates 31 and 32. The electrode plates 31 and 32 can be nickel-plated brass or nickel-plated copper, or other metals with good conductivity. The electrical disconnecting device 33 is an active disconnecting mechanism that will actively disconnect without external force. The tripping device 22 and the electrical disconnecting device 33 are in contact. Before the tripping device is activated, the electrical disconnecting device 33 remains conductive due to the contact of the tripping device 22, and the electrode plates 31 and 32 are electrically connected, allowing current to flow. When the tripping device is activated, the electrical disconnecting device 33 will actively disconnect, breaking the circuit of the electrode plates 31 and 32 through the electrical disconnecting device 33.
[0044] The high-voltage circuit disconnection device 40 is an overcurrent disconnection device. Its two ends are connected to the two electrode plates of the current-carrying device 30 by means of brazing or welding. After the electrical disconnection device 33 of the electrode plates 31 and 32 is disconnected, all the current in the circuit will pass through the high-voltage circuit disconnection device 40, and the high-voltage circuit disconnection device 40 will disconnect quickly due to overcurrent.
[0045] Example 1
[0046] As shown in Figures 1 to 4, this disclosure provides a specific embodiment of a fast-response thermal fuse. The housing assembly 10 consists of a cover plate 101, a housing 108, and a base plate 115, etc.; the circuit current-carrying device 30 consists of electrode plates 103 and 104, contacts 106, and spring plates 107, etc.; the tripping device 22 consists of a push rod 105, a base 110, springs 111 and 112, and a limiting block 113, etc.; the bimetallic strip 114 corresponds to the bimetallic strip 21 in the protection triggering device 20; the circuit high-voltage disconnecting device 40 mainly consists of a fuse 109.
[0047] In this embodiment, the base plate 115 is circular and is fixedly connected to the outer casing 108 by a hook 116. The base plate 115 is used to contact a heat source and conduct heat to the bimetallic strip 114. When the temperature reaches a certain level, the bimetallic strip 114 will warp and deform, and this deformation will act on the tripping device, pushing the tripping device to trip.
[0048] Bimetallic strip 114 corresponds to bimetallic strip 21 in protection triggering device 20; base 110, springs 111 and 112, limit block 113, push rod 105, etc. constitute the tripping device in protection triggering device 20; electrode plates 103 and 104, contact 106, and spring 107 constitute circuit current carrying device 30, wherein electrode plates 103 and 104 correspond to electrode plates 31 and 32 in circuit current carrying device 30, respectively, and contact 106 and spring 107 are respectively disposed on electrode plates 103 and 104. The two contact with each other under the action of external force form an electrical connection, constituting electrical disconnecting device 33 in circuit current carrying device 30. Fuse 109 is the core component in circuit high voltage disconnecting device, which melts when there is overcurrent. Fuse 109 can be pure silver wire, copper wire, or other metal wire with good electrical and thermal conductivity and a suitable melting point. Its two ends are electrically connected to electrode plates 31 and 32 by brazing, resistance welding, etc. Typically, an environmentally friendly filler 102, such as an arc-extinguishing medium, is filled around the fuse 109 to prevent arcing when the fuse melts. In other embodiments, the core component of the high-voltage circuit breaking device 40 is a fuse connected in series with a low-melting-point alloy, surrounded by a fluxing agent.
[0049] More specifically, the base plate 115 is the heat-conducting structure of this fast-response thermal fuse, typically made of metal materials such as copper alloy or stainless steel, and is positioned to fit the heat source during application. The cover plate 101 and the outer shell 108 are made of insulating, heat-resistant, and explosion-proof ceramic materials to ensure the safe use of the fast-response thermal fuse.
[0050] In this embodiment, the bimetallic strip 114 is dish-shaped and fixed to the base plate 115 or the outer shell 108 around its perimeter. The middle part is a movable end that fits against the base plate 115, allowing heat from the base plate 115 to be quickly conducted to the bimetallic strip 114. When the bimetallic strip 114 reaches a set temperature, its middle part will warp upwards.
[0051] The base 110 is fixedly embedded in the housing 108. The housing 108 has multiple through slots. The push rod 105 is slidably disposed within the housing 108 and can move axially under external force. The limiting block 113 is slidably disposed within the housing 108. Springs 111 and 112 are disposed between the limiting block 113 and the base 110 and are in a compressed state. Springs 111 and 112 exert force on the limiting block 113, causing the limiting block 113 and the movable end of the bimetallic strip 114 to be in abutting state; simultaneously, the limiting block 113 and the push rod 105 remain in abutting state, restricting the axial movement of the push rod 105.
[0052] More specifically, the limiting block 113 includes a mountain-shaped plate structure; the bottom center of the mountain-shaped plate structure protrudes and abuts against the center of the bimetallic strip 114. An elongated hole 1131 is provided on the central protrusion of the mountain-shaped plate structure, and an annular groove 1051 is provided on the side of the push rod 105. The push rod 105 is perpendicular to the limiting block 113 and passes through the elongated hole 1131. The groove 1051 and the hole wall of the elongated hole 1131 form a snap-fit engagement.
[0053] In this embodiment, when the bimetallic strip warps due to heat, it pushes the limiting block 113 upward, releasing the engagement between the groove 1051 and the wall of the elongated hole 1131. At this time, the push rod 105 separates from the other components of the tripping device and is in a tripped state. It cannot apply force to the electrical disconnecting device 33, so the electrical disconnecting device 33 actively disconnects and pushes the push rod 105 away.
[0054] In this embodiment, the electrical disconnecting device 33 includes a contact 106 and a spring 107. In the non-disconnected state, one end of the push rod 105 abuts against the middle of the spring 107, pressing the spring 107 down to contact the contact 106, forming an electrical connection, and the main circuit of the electrode plates 103 and 104 is connected. At this time, the spring 107 is in an elastic energy-storing state. When the tripping device trips, the push rod 105 is in the disconnected state, the elastic energy of the spring 107 is released, pushing the push rod 105, causing it to disengage from the elongated hole 1131, simultaneously releasing the contact between the spring 107 and the contact 106, and disconnecting the current-carrying circuit.
[0055] This embodiment uses a disc-shaped bimetallic strip, and the push rod is arranged horizontally, which is suitable for packaging structures with low height.
[0056] Example 2:
[0057] As shown in Figures 1, 5 to 7, this disclosure provides another embodiment of a fast-response thermal fuse. The housing assembly 10 consists of a housing 208, a cover plate 201, and a base plate 214, etc.; the circuit current-carrying device 30 consists of electrode plates 202 and 203, contacts 204, and a spring 205, etc.; the tripping device 22 consists of a push rod 207, a base 211, a swing arm 212, a spring 209, and a limiting rod 210, etc.; the bimetallic strip 213 corresponds to the bimetallic strip 21 in the protection triggering device 20; and the high-voltage circuit disconnecting device 40 mainly consists of a fuse 109.
[0058] In this embodiment, the base plate 214 is rectangular and is fixedly connected to the outer shell by rivets 215 and 216.
[0059] In this embodiment, the composition of the circuit current-carrying device 30 and the circuit high-voltage disconnection device 40 is not significantly different from that in Embodiment 1. Their implementation has been described in Embodiment 2 and will not be elaborated here.
[0060] In this embodiment, the bimetallic strip 213 is strip-shaped, with one end fixed to the heat-conducting base plate 214 and the other movable end abutting against the first end of the swing arm 212.
[0061] The base 211 is fixed inside the housing 208. The housing 208 and the base 211 provide a first through groove and a second through groove that intersect in a cross shape for the push rod 207 and the limiting rod 210. The push rod 207 is disposed in the first through groove and the limiting rod 210 is disposed in the second through groove.
[0062] The middle part of the swing arm 212 is axially connected to the outer casing 208. One end of the swing arm 212 abuts against the movable end of the bimetallic strip 213, and the other end abuts against one end of the limiting rod 210. The other end of the limiting rod 210 protrudes into the first through groove and abuts against the push rod 207. The other end of the push rod 207 abuts against the spring 205, so that the spring 205 and the contact 204 abut against each other to form an electrical connection, thereby putting the circuit current-carrying device 30 in a connected state. The end of the limiting rod 210 that abuts against the swing arm is provided with a limiting cap. The second through groove is a stepped through groove. The spring 209 is sleeved on the limiting rod 210. One end of the spring 209 abuts against the inner side of the limiting cap, and the other end abuts against the step of the stepped through groove. It is in an energy storage state, thereby applying a force to the limiting rod 210 in the direction of the swing arm 212.
[0063] When the bimetallic strip 213 warps due to heat, the swing arm 212 rotates under the force of the bimetallic strip 213. The end of the swing arm 212 that abuts against the bimetallic strip 213 tilts upward, while the other end of the swing arm 212 moves downward, releasing its contact with the limiting rod 210. Under the action of the spring 209, the limiting rod 210 exits from the first through slot, releasing the contact between the limiting rod 210 and the push rod 207, thereby releasing the force of the push rod 207 on the spring 205. The electrical disconnect device disconnects under the elastic force of the spring 205. Preferably, the swing arm 212 is provided with an arc-shaped clearance groove that matches the shape of the limiting cap, so that the contact between the limiting rod 210 and the push rod 207 can be released by a small movement distance, allowing the limiting rod 210 to make way. This embodiment uses a strip-shaped bimetallic strip, and the push rod is vertically arranged, which is suitable for a narrower encapsulation structure.
[0064] Example 3:
[0065] As shown in Figures 1, 8 to 10, this disclosure provides another embodiment of a fast-response thermal fuse. The housing assembly 10 consists of a housing 311, a cover plate 301, and a base plate 315, etc.; the circuit current-carrying device 30 consists of electrode plates 302 and 303, contacts 304, and a spring 307, etc.; the tripping device 22 consists of a push rod 305, a base 308, a limiting block 309, a swing arm 310, and a spring 306, etc.; the bimetallic strip 314 corresponds to the bimetallic strip 21 in the protection triggering device 20; and the high-voltage circuit disconnecting device 40 mainly consists of a fuse 312.
[0066] The base 308 is fixed inside the housing 311 and provides a first through groove and a second through groove that intersect the push rod 305 and the limiting block 309. The push rod 305 is disposed in the first through groove and the limiting block 309 is disposed in the second through groove.
[0067] The swing arm 310 is disposed at the bottom of the base 308. The bottom of the base 308 is provided with a protrusion as the swing fulcrum of the swing arm 310. A groove is provided in the middle of the swing arm 310, which cooperates with the protrusion. One end of the swing arm 310 abuts against the movable end of the bimetallic strip 314, and the other end abuts against the limiting block 309. More specifically, a limiting step 3091 is provided on the limiting block 309; when the bimetallic strip 314 is heated and warped, the swing arm 310 rotates around the swing fulcrum by a certain angle or distance under the action of the bimetallic strip 314. With the cooperation of the swing arm 310 and the limiting step 3091 of the limiting block 309, the limiting block 309 is pushed to move away from the push rod 305 and exit the first through slot, releasing the supporting effect of the limiting block 309 on the push rod 305. As a result, the push rod 305 is released from the contact state with the spring 307 under the elastic force of the spring 306, and the electrical disconnection device is disconnected under the elastic force of the spring 307, thereby cutting off the circuit.
[0068] A limiting cap is provided at one end of the push rod 305 and the limiting block 309. The first through groove is a stepped through groove. The spring 306 is sleeved on the push rod 305. One end of the spring 306 abuts against the inner side of the limiting cap, and the other end abuts against the step of the stepped through groove. It is in an energy storage state, thereby applying a force to the push rod 305 in the direction of the limiting block 309.
[0069] This embodiment uses a disc-shaped bimetallic strip, and the push rod is arranged horizontally, which is suitable for packaging structures with low height.
[0070] The fast-response thermal fuse in the above embodiments integrates the advantages of both bimetallic strip and low-melting-point alloy technologies while overcoming their disadvantages, thus improving the user experience and significantly enhancing product performance. The integrated fast-response thermal fuse has the following technical characteristics:
[0071] Fast response speed;
[0072] Temperature adjustable;
[0073] The operating temperature is highly accurate and stable;
[0074] High breaking capacity, up to 1500VDC;
[0075] Small size;
[0076] Disposable products, with no contact bonding occurring;
[0077] The operating temperature is the same as the holding temperature;
[0078] Resistant to high and low temperature shocks;
[0079] No epoxy resin encapsulation required;
[0080] It has high temperature resistance, reaching 500–1000℃;
[0081] Easy to install.
[0082] The terms "an embodiment," "embodiment," or "one or more embodiments" as used herein mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of this disclosure. Furthermore, please note that the examples of the phrase "in one embodiment" do not necessarily all refer to the same embodiment.
[0083] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this disclosure may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.
[0084] In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. This disclosure can be implemented by means of hardware comprising a plurality of different elements and by means of a suitably programmed computer. In a unit claim enumerating a plurality of means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words may be interpreted as names.
[0085] Although this disclosure has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to this disclosure without departing from the spirit and scope of this disclosure as defined by the appended claims, and all such changes shall be within the scope of protection of this disclosure.
Claims
1. A fast-response thermal cut-off, characterized by: It includes a housing, a bimetallic strip disposed in the housing, a tripping device, a first electrode, a second electrode, and an electrical disconnecting device bridging the first electrode and the second electrode; The two ends of the tripping device abut against the movable end of the bimetallic strip and the electrical disconnecting device, respectively. The bimetallic strip is close to the housing; when the bimetallic strip is heated and deformed, it pushes the tripping device and the electrical disconnecting device to disengage from the contact state. The electrical disconnect device remains in a conductive state under the external force applied by the tripping device, and is in a disconnected state when the external force is removed.
2. The fast response thermal cutoff device of claim 1 wherein: the thermistor is a positive temperature coefficient thermistor. The electrical disconnect device includes contacts and a spring, which are respectively disposed on the first electrode and the second electrode. When an external force is applied, the spring abuts against the contact, so that the electrical disconnect device is in a conductive state; when the external force is removed, the spring moves away from the contact under its elastic force, so that the electrical disconnect device is in a disconnected state.
3. The fast response thermal cutoff device of claim 1 wherein: the thermistor is a positive temperature coefficient thermistor. The tripping device includes a base, a limiting block, a push rod, and an elastic element; The push rod has a groove; the limiting block has a plate-like structure with a through hole. One end of the limiting block abuts against the movable end of the bimetallic strip, serving as the operating end of the tripping device. One end of the push rod passes through the through hole, causing the groove and the through hole to engage. The elastic element is disposed between the limiting block and the base, applying a force to the limiting block in the direction of the bimetallic strip, keeping the movable ends of the limiting block and the bimetallic strip in abutment and keeping the groove and the through hole engaged. The other end of the push rod abuts against the electrical disconnecting device, keeping the electrical disconnecting device in a conductive state. When the tripping device is activated, the movable end of the bimetallic strip pushes the limiting block away from the bimetallic strip, disengaging the groove and the through hole from the engaged state. The push rod moves away from the electrical disconnecting device under the reverse force of the electrical disconnecting device.
4. The fast response thermal cutoff device of claim 1 wherein: the thermistor is a positive temperature coefficient thermistor. The tripping device includes a swing arm, a base, a limiting rod, a push rod, and an elastic element; The swing arm is the operating end of the tripping device; the base is provided with a first through groove for limiting the movement of the limiting rod back and forth in a first direction; the base is provided with a second through groove or a second cavity is provided outside the base for limiting the movement of the push rod back and forth in a second direction; the first direction and the second direction are perpendicular; the push rod is the tripping end of the tripping device. The movement directions of the swing arm and the limiting rod are perpendicular, and the movement directions of the limiting rod and the push rod are perpendicular; One end of the swing arm abuts against the movable end of the bimetallic strip, and the other end abuts against one end of the limiting rod; the other end of the limiting rod extends out of the base and abuts against one end of the push rod; the end face of the other end of the push rod abuts against the electrical disconnect device. The elastic element is used to apply a force toward the swing arm to the limiting rod.
5. The fast response thermal cutoff device of claim 4 wherein: the thermistor is a positive temperature coefficient thermistor. One end of the limiting rod is provided with a limiting cap with a diameter larger than that of the first through groove. The first through groove is a stepped through groove. One end of the elastic member abuts against the inner side of the limiting cap, and the other end abuts against the step of the stepped through groove.
6. The fast response thermal cutoff device of claim 4 wherein: the thermistor is a positive temperature coefficient thermistor. The swing arm is provided with an arc-shaped clearance groove.
7. The fast response thermal cutoff device of claim 1 wherein: the thermistor is a thermistor having a positive temperature coefficient of resistance. The tripping device includes a base, a swing arm, a limiting block, a push rod, and an elastic element; The swing arm is the operating end of the release device; the base is provided with a first through groove for limiting the push rod to move back and forth in a first direction, and a second through groove for limiting the limit block to move back and forth in a second direction, the first direction and the second direction being perpendicular; the push rod is the release end of the release device; The base is provided with a fulcrum for the swing arm to swing, and the middle part of the swing arm abuts against the fulcrum; one end of the limiting block is provided with a limiting step; one end of the swing arm abuts against the movable end of the bimetallic strip, and the other end abuts against the inner side of the limiting step; the other end of the limiting block abuts against one end of the push rod in the first through groove, and the other end of the push rod extends out of the base and abuts against the electrical disconnect device; The elastic element is used to apply a force toward the limiting block to the push rod.
8. The fast-response thermal fuse as described in claim 7, characterized in that: The first through groove is a stepped through groove, with one end of the elastic member abutting against the inner side of the limiting cap and the other end abutting against the junction of the stepped through groove.
9. The fast-response thermal fuse as described in claim 1, characterized in that: The housing includes a cover plate, an outer shell, and a base plate. The base plate is a heat-conducting plate. Before thermal deformation, the movable end of the bimetallic strip overlaps with the base plate; after thermal deformation, the movable end of the bimetallic strip disengages from the base plate.
10. The fast-response thermal fuse as described in any one of claims 1-9, characterized in that: It also includes a high-voltage circuit breaking device, which includes a fuse, or a fuse connected in series with a low-melting-point alloy, and the two ends of the high-voltage circuit breaking device are respectively connected to the first electrode and the second electrode.