Insulation wire rod type thermal fuse-link

Abstract

An insulating wire rod type thermal fuse link comprises an insulating shell, a first wire rod and a second wire rod, a first spring, a contact piece, a second spring and an organic matter temperature sensing body are arranged in the insulating shell, the first wire rod and the second wire rod penetrate into and are fixed from the two ends of the insulating shell respectively, the inner end of the first wire rod makes contact with the contact piece when the first spring is compressed, and the outer end of the second wire rod makes contact with the organic matter temperature sensing body when the second spring is compressed. The inner end of the second wire rod is welded and conducted with the contact piece. The first spring and the second spring abut against the two sides of the contact piece respectively. The organic matter temperature sensing body compresses the second spring to abut against the contact piece, and the first spring and the second spring compress each other to enable the first wire rod to make close contact with the contact piece. When the organic matter temperature sensing body is converted into a liquid state from a solid state, the second spring releases elastic force, the first spring which is not abutted pushes the contact piece to be separated from the first wire rod, and a current conduction loop is cut off. According to the utility model, the whole external part is insulated, the installation short circuit risk can be avoided, the sleeve material cost is saved, time and labor are saved, and the insulation strength of the product is greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit protection, and more specifically to an insulating wire type thermal fuse. Background Art

[0002] Thermal fuses are electronic parts that are one-time and cannot be reset. They are widely used in thermal protection of household appliances, automobiles, smart bathrooms and other similar components to prevent them from overheating in the event of a fault. Traditional thermal fuses have metal shells. Since the outside of the fuse is charged, a sleeve is required to be used to insulate it from the outside when the terminal equipment is installed. In this way, during installation, if the operation is improper, such as the sleeve is loose, the metal shell of the thermal fuse will be exposed, causing the thermal fuse to have the risk of short circuit, losing the thermal protection effect, and posing a safety hazard. In this context, the market urgently needs thermal fuses that can be used directly and normally in terms of structure, and the shell can be insulated to eliminate the risk of short circuit due to improper installation.

[0003] For example, Chinese patent application No. 202310948196.6 discloses a high-voltage thermal fuse, in which when the organic thermal fuse senses abnormal heat and reaches a predetermined melting temperature, the temperature-sensing body melts, and the movable electrode is separated from the static contact under the action of the spring, thereby disconnecting the circuit. However, its electrode assembly is in contact with the conductive shell, and the conductive shell is still used to participate in the current loop, so an insulating sleeve is required, which also poses a safety hazard.

[0004] Another example is a fuse for outdoor circuit protection with Chinese patent application number 201710727369.6, which changes the traditional insulating shell into an inner ceramic outer insulating tube. The spring is loaded into the inner cavity in a compressed state. Its elastic force can support the disconnecting electrode with the help of a gasket to keep it in contact with the moving contact piece. When the ambient temperature exceeds the operating temperature, the heat transmitted through the left and right leads turns the temperature sensor into liquid, and the spring pops out and stretches to push the disconnecting electrode away, cutting off the contact with the moving contact piece and cutting off the circuit. This patent is essentially a current protector. The temperature sensor directly participates in the conduction. Since the temperature sensor must contain conductive components, when the circuit fails, it may cause the shell to explode. After the shell explodes, the liquid temperature sensor sprays outward, causing pollution and affecting the external circuit board, increasing safety hazards.

[0005] Another example is the thermal fuse and electrical equipment of Chinese patent application No. 202110239059.6. The shell of the thermal fuse adopts an insulating shell. When the current in the circuit exceeds the specified value, the thermistor in the accommodating cavity melts due to heat, and the heat insulating member moves toward the end away from the fixed seat, so that the elastic force of the first elastic member is released and pushes the conductive member to move toward the end away from the fixed seat, so that the conductive member is separated from the first pin and the second pin to cut off the circuit. Although the above-mentioned thermal fuse has insulation and waterproof effects, it has the following disadvantages: (1) The electrodes on the same side (the first pin 23 and the second pin 25) need to meet the industry standard spacing. If the two are too close, after the circuit is cut off, the electrical clearance (or creepage distance) between the first pin 23 and the second pin 25 is not enough, and conduction will still occur, and the fuse cannot be blown. Therefore, the product cannot be miniaturized and the production process is also high; (2) The two ends of the conductive member 30 are only in end face contact with the first pin 23 and the second pin 25, and the contact area is small, the corresponding internal resistance is large, and the self-heating is large. , the temperature required by the design may not be reached, and the thermistor 60 will be melted in advance and the circuit will be cut off; (3) The conductive member 30 is formed in a U shape, and its lower surface is in contact with the heat insulating member 50. It is easy to tilt during the movement and cannot bounce into place, so that the distance between the two ends of the conductive member 30 and the first pin 23 and the second pin 25 does not reach the complete disconnection distance, and the circuit cannot be truly cut off; (4) The conductor 30 is U-shaped or cylindrical, with a large area and high cost; (5) The first wire 80 and the second wire 90 only have a conductive function and do not participate in the movement. This design concept limits the design of the conductive member 30.

[0006] In view of this, the designer has made in-depth considerations and actively researched, improved and trial-made the present invention to address the many deficiencies and inconveniences caused by the imperfect structural design of the above-mentioned thermal fuse. Utility Model Content

[0007] The utility model aims to provide an insulated wire type thermal fuse, which has an overall external insulation, can avoid the risk of installation short circuit, save the cost of casing materials, save time and labor, and greatly improve the insulation strength of the product.

[0008] In order to achieve the above purpose, the solution of the utility model is:

[0009] An insulating wire type thermal fuse comprises an insulating shell, a first wire and a second wire. The insulating shell is provided with a first spring, a contact piece, a second spring and an organic temperature sensor. The first wire and the second wire are respectively inserted and fixed from two ends of the insulating shell. The inner end of the first wire contacts the contact piece when the first spring is compressed, and the inner end of the second wire is welded and connected to the contact piece. The first spring and the second spring are respectively supported on both sides of the contact piece. The organic temperature sensor compresses the second spring to support the contact piece, and the first spring and the second spring compress each other to closely contact the first wire with the contact piece. When the organic temperature sensor changes from a solid state to a liquid state, the second spring releases its elastic force, and the first spring that is not supported pushes the contact piece to separate from the first wire, thereby cutting off the current conduction circuit.

[0010] Furthermore, the entire second wire or the portion located inside the insulating tube is a flexible wire with shrinkable length.

[0011] Furthermore, the second spring is sleeved on the second wire and is located between the organic temperature sensing body and the contact sheet, and the inner end of the second wire passes through a through hole provided in the middle of the organic temperature sensing body.

[0012] Furthermore, the insulating shell is made of plastic, and a plastic upper cover is fixed to one end of the insulating shell by a buckle, and the first wire is positioned integrally with the plastic upper cover.

[0013] Furthermore, the first spring is sleeved on an inner column protruding from the inner side surface of the plastic upper cover.

[0014] Furthermore, the second wire is inserted into a through hole provided at the end of the insulating shell, and the through hole is filled with epoxy resin that can seal and fix the second wire to the end of the insulating shell.

[0015] Furthermore, the organic temperature sensor is a thermosensitive material with a melting point of 60°C-300°C.

[0016] After adopting the above structure, the thermal fuse of the utility model is insulated as a whole, which can eliminate the risk of short circuit caused by improper installation, and is easy to install, saves the cost of casing materials, saves time and effort, and greatly improves the safety factor and production efficiency of the product. The utility model has a simple structure, is easy to assemble, is safer to use and has a lower cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a three-dimensional structural schematic diagram of the utility model;

[0018] Figure 2 It is a cross-sectional schematic diagram of the utility model in a conducting state;

[0019] Figure 3 It is a cross-sectional schematic diagram of the utility model in a disconnected state. DETAILED DESCRIPTION

[0020] In order to further explain the technical solution of the present utility model, the present utility model is described in detail below through specific embodiments.

[0021] Combination Figures 1 to 3 As shown, the utility model discloses an insulated wire type thermal fuse, including an insulating shell 1, a first wire 2, and a second wire 3. The insulating shell 1 is provided with a first spring 4, a contact piece 5, a second spring 6, and an organic temperature sensor 7. A cavity is formed in the middle of the insulating shell 1, and the inner ends of the first wire 1 and the second wire 2 can be inserted and fixed from the two ends of the insulating shell respectively. When the first spring 4 is compressed, the inner end of the first wire 2 is in contact with the contact piece 5, and the inner end of the second wire 3 is welded and connected with the contact piece 5 to achieve electrical conduction. The first spring 4 and the second spring 6 are respectively supported on both sides of the contact piece 5. The organic temperature sensor 7 is located on one side of the second wire 6. The organic temperature sensor 7 in a solid state can compress the second spring 6 to make it support the contact piece 5, so that the first spring 4 and the second spring 6 are compressed against each other to make the first wire 2 in close contact with the contact piece 5. When the current in the circuit exceeds the specified value and the ambient temperature reaches or exceeds the melting point of the organic temperature sensor, the organic temperature sensor changes from solid to liquid, and the second spring 6 releases its elastic force after losing its support. At this time, the first spring 4 that is not pushed can push the contact piece 5 to separate from the first wire 2, and the first wire 2 loses contact with the contact piece 5, thereby cutting off the current conduction circuit.

[0022] Specifically, when the second spring 6 changes from a compressed state to a free length state, the second spring 6 will rebound downward to the space supported by the original object temperature sensing body 7, such as Figure 3 As shown, in order to enable the first spring 4 to push the contact piece 5 to move in the direction of the second spring outward, the second wire 3 on the other side can smoothly drive the contact piece 5 to move downward, so that the second wire 3 as a whole or at least the part located inside the insulating tube body 1 is a flexible wire with a retractable length. The second wire 3 can be formed by twisting multiple strands of soft wires. At least the part of the second wire 3 located inside the insulating shell 1 not only has a conductive function, but also participates in the movement when the current is cut off, so that the contact piece 5 welded thereon is bounced off and leaves the contact with the first wire 2. Further, the second spring 6 can be directly sleeved on the second wire 3 and located between the organic temperature sensor 7 and the contact piece 5, and the inner end of the second wire 3 can directly pass through the through hole provided in the middle of the organic temperature sensor 7.

[0023] In this embodiment, the insulating shell 1 can be made of plastic material, and one end of the insulating shell 1 can be fixed with a plastic upper cover 11 by a buckle, and the first wire 2 can be directly positioned together with the plastic upper cover by injection molding. The first spring 4 can be mounted on the inner column 111 convexly provided on the inner side of the plastic upper cover 11 for easy positioning. At the other end of the insulating shell, the second wire 3 can be inserted into the through hole (not shown in the figure) provided at the end of the insulating shell 1, and the through hole is filled with epoxy resin 8 to seal and fix the second wire 3 on the insulating shell 1. The organic temperature sensor 7 is a heat-sensitive material with a melting point of 60°C-300°C. The organic temperature sensor 5 is placed in the insulating shell 1. The organic temperature sensor 5 is deformed after being heated and does not participate in conduction.

[0024] When the utility model is used, Figure 2 , Figure 3 As shown, the circuit conduction current-carrying components are in order: the first wire 2, the contact piece 5, and the second wire 3. When the temperature is not sensed in the normal state, the above current-carrying components are in contact and connected one by one to form a conduction circuit. Figure 3 As shown, when the temperature sensed by the insulated wire type thermal fuse reaches or exceeds the melting point temperature of the organic temperature sensor 7, the organic temperature sensor 7 will change from solid to liquid and no longer play a supporting function, and the compressed second spring 6 will change from a compressed state to a free length state, so that the first spring 4 can push the contact piece 5 to move. Since the second wire 3 is soft and can shrink, the contact piece 5 is separated from the first wire 2, cutting off the current conduction circuit and achieving thermal protection.

[0025] When the end customer installs the insulated wire type thermal fuse of the utility model, it is only necessary to connect the two ends of the first wire 2 and the second wire 3. Since the shell is an insulating shell, the entire current loop does not need to pass through the shell as a conductive medium, which can avoid the exposed charged metal shell of the traditional thermal fuse, or the need to install an insulating sleeve, and eliminate the risk of short circuit due to improper installation. It is easy to install, saves the cost of sleeve materials, saves time and effort, and greatly improves the safety factor and production efficiency of the product. In addition, the overall assembly of the utility model is simple, and the material cost and production process requirements are lower. During assembly, the mechanical temperature sensor 7 and the second spring 6 can be passed through the second wire 3, the second wire 3 can be inserted into the insulating shell cavity and then passed out, and then the contact piece 5 can be inserted, and finally the first spring 4 can be fixed, and the plastic cover 11 can be covered and buckled. The utility model can be widely used in household appliances, bathroom equipment, lighting fields, automotive fields, etc., can meet the risk assessment of various fields, and has a wide range of applications.

[0026] The standard parts used in the utility model can all be purchased from the market, and special-shaped parts can be customized according to the instructions and the drawings. The specific connection methods of each part adopt the conventional means such as mature bolts, rivets, welding, etc. in the existing technology. The machinery, parts and equipment all adopt the conventional models in the existing technology, and the circuit connection adopts the conventional connection method in the existing technology, which will not be described in detail here.

[0027] The above embodiments and drawings do not limit the product form and style of the present utility model. Any appropriate changes or modifications made by ordinary technicians in the relevant technical field should be deemed to be within the patent scope of the present utility model.

Claims

1. An insulated wire type thermal fuse, characterized in that: The invention comprises an insulating shell, a first wire and a second wire. The insulating shell is provided with a first spring, a contact sheet, a second spring and an organic temperature sensor. The first wire and the second wire are respectively inserted and fixed from two ends of the insulating shell. The inner end of the first wire contacts the contact sheet when the first spring is compressed, and the inner end of the second wire is welded and connected to the contact sheet. The first spring and the second spring are respectively supported on both sides of the contact sheet. The organic temperature sensor compresses the second spring to support the contact sheet, and the first spring and the second spring compress each other to make the first wire closely contact the contact sheet. When the organic temperature sensor changes from a solid state to a liquid state, the second spring releases its elastic force, and the first spring, which is not supported, pushes the contact sheet to separate from the first wire, thereby cutting off the current conducting circuit.

2. An insulated wire type thermal fuse according to claim 1, characterized in that: The entire second wire or the portion of the second wire located inside the insulating tube is a flexible wire with a retractable length.

3. An insulated wire type thermal fuse according to claim 1 or 2, characterized in that: The second spring is sleeved on the second wire and is located between the organic temperature sensing body and the contact sheet, and the inner end of the second wire passes through a through hole provided in the middle of the organic temperature sensing body.

4. The insulated wire type thermal fuse according to claim 1, characterized in that: The insulating shell is made of plastic, and a plastic upper cover is fixed to one end of the insulating shell by a buckle, and the first wire is positioned integrally with the plastic upper cover.

5. An insulated wire type thermal fuse according to claim 4, characterized in that: The first spring is sleeved on an inner column convexly arranged on the inner side surface of the plastic upper cover.

6. An insulated wire type thermal fuse according to claim 1, characterized in that: The second wire is inserted into a through hole provided at the end of the insulating shell, and the through hole is filled with epoxy resin which can seal and fix the second wire to the end of the insulating shell.

7. An insulated wire type thermal fuse according to claim 1, characterized in that: The organic temperature sensor is a heat-sensitive material with a melting point of 60°C-300°C.

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