Thermally sensitive pellet type temperature fuse

Abstract

The present application provides a temperature sensing granule type temperature fuse, which is excellent in reliability such as insulation after operation. Inside a cylindrical case having good electric conductivity and good heat conductivity, there are at least: temperature sensing granules which melt or soften at a certain temperature; a strong compression spring which pushes the temperature sensing granules; an insulating cover which seals the open end of the cylindrical case; a weak compression spring which abuts against the insulating cover; a first lead wire which uses the inner end of the insulating cover as a fixed contact; and a movable contact which is electrically connected to the first lead wire and the cylindrical case. The second lead wire is arranged on one side of the cylindrical case. At the sealing part of the cylindrical case, the outer end base of the first lead wire is at least shielded by the insulating unit arranged between the open end of the cylindrical case and the first lead wire, and the cylindrical case, the first lead wire and the insulating cover are sealed by the sealing resin.

Description

Technical Field

[0001] This invention relates to a temperature-sensitive particle-type thermal fuse that cuts off electrical circuits when sensing overheating in electrical equipment, etc. Background Technology

[0002] Thermal fuses are protective components used in household electrical products or industrial electrical or electronic equipment to sense the temperature of the device and quickly cut off the circuit in case of abnormal overheating. Examples of thermal fuses include those found in household appliances, portable devices, communication equipment, office equipment, vehicle-mounted equipment, AC adapters, chargers, motors, and batteries. Generally, thermal fuses are available with rated current values ​​ranging from approximately 0.5A to 15A, but for high rated currents above 6A, temperature-sensing granular thermal fuses are particularly preferred. As a representative form of temperature-sensitive granular thermal fuse, for example, as shown in Patent Document 1, there exists a temperature-sensitive granular thermal fuse comprising: a cylindrical metal housing (hereinafter, cylindrical housing) having a hollow interior; a temperature-sensitive granule having a first lead and a second lead disposed at both ends of the cylindrical housing and configured to be connected to the second lead; and a movable contact that abuts against the first lead via the temperature-sensitive granule and is always exerted with force in the separation direction. When the temperature of the mounted electrical equipment reaches or exceeds a given temperature, the temperature-sensitive granule melts or softens, thereby causing the movable contact to separate from the first lead due to the force and cut off the circuit. By connecting the aforementioned temperature-sensitive granular thermal fuse in series with the electrical equipment and placing it at the location where an abnormal temperature rise in the electronic or electrical equipment to be detected can be detected, power can be supplied to the electrical equipment via the temperature-sensitive granular thermal fuse. The temperature-sensing particle is solid at normal temperatures. At this temperature, the force exerted pushes the movable contact, causing it to contact the inner end of the first lead's housing. Therefore, the first lead – movable contact – cylindrical housing – second lead remain in a conductive state. Furthermore, if the temperature at the installation location rises to the operating temperature of the temperature-sensing particle-type thermal fuse due to abnormal power supply such as a short circuit in the electrical equipment, the temperature-sensing particle melts. The force pushing the movable contact to contact the end of the first lead decreases or even disappears, causing the movable contact to separate from the inner end of the first lead's housing. The first and second leads then become non-conductive. Thus, the power supply to the electrical equipment is stopped, preventing the temperature from rising and thus preventing overheating damage or fires.

[0003] (Existing technical literature)

[0004] (Patent Documents)

[0005] Patent document 1: JP Japanese Patent Application Publication No. 01-154422;

[0006] Patent document 2: JP 2005-158681. Summary of the Invention

[0007] (The problem the invention aims to solve)

[0008] Existing temperature-sensitive particle type thermal fuses, such as Figure 6 As shown in the temperature-sensitive particle type thermal fuse 60, inside a cylindrical housing 61 with good electrical and thermal conductivity, there are temperature-sensitive particles 62 that melt or soften at a specific temperature, a strong compression spring 63 that pushes the temperature-sensitive particles 62, an insulating cover 64 that closes the open end 600 of the cylindrical housing 61, a weak compression spring 65 that abuts against the insulating cover 64, a first lead 66 that passes through the inner end of the insulating cover 64 as a fixed contact, and a movable contact 67 that is electrically connected to the first lead 66 and the cylindrical housing 61. The temperature-sensitive particle type thermal fuse 60 also has a second lead 68 disposed on one side of the cylindrical housing 61. The insulating cover 64 retracts and rivets the open end 600 of the cylindrical housing 61, thereby fixing the insulating cover 64 to the open end 600 in a way that prevents it from protruding outward and falling off due to the force of the spring. Furthermore, the first lead 66 is extended at its outer end base 601 by crimping, thereby being fixed in a state where it is inserted into the through hole provided in the center of the insulating cover 64. The cylindrical housing 61, the first lead 66, and the insulating cover 64 are sealed with sealing resin 602. The open end 600 of the cylindrical housing 61 is riveted towards the first lead 66 on the central axis of the cylindrical housing 61, thus the insulation distance between the open end 600 of the cylindrical housing 61 and the first lead 66 is narrowest. Therefore, the insulation performance of the thermal fuse depends on the volume resistivity of the sealing resin 602. This is particularly significant at high temperatures, where a limit is created for the withstand voltage and insulation performance maintenance at high temperatures.

[0009] The purpose of this invention is to provide a temperature-sensitive particle-type temperature fuse that can improve the insulation resistance of the temperature-sensitive particle-type temperature fuse and has excellent reliability, including insulation performance after operation.

[0010] (Technical solution used to solve the problem)

[0011] According to a first embodiment of the present invention, the interior of a cylindrical shell with good electrical and thermal conductivity includes at least: a temperature-sensitive particle that melts or softens at a specific temperature; a strong compression spring that pushes the temperature-sensitive particle; an insulating cover that closes the open end of the cylindrical shell; a weak compression spring that abuts against the insulating cover; a first lead wire that serves as a fixed contact with its inner end penetrating the insulating cover; and a movable contact that is electrically connected to the first lead wire and the cylindrical shell. The temperature-sensitive particle type thermal fuse further includes a second lead wire disposed on one side of the cylindrical shell. At the sealing portion of the cylindrical shell, an insulating unit disposed between the open end of the cylindrical shell and the first lead wire at least covers the outer base of the first lead wire, and the cylindrical shell, the first lead wire, and the insulating cover are sealed with sealing resin. The insulating unit, in addition to improving the electrical insulation of the narrowest part of the insulation distance between the cylindrical shell and the first lead wire, also improves heat resistance while ensuring mechanical strength.

[0012] This invention provides a temperature-sensitive particle-type thermal fuse in which an insulating tube is sandwiched as an insulating unit between the narrowest part of the cylindrical housing and the first lead and sealed with a sealing resin. For example, a temperature-sensitive particle-type thermal fuse is provided as follows: inside a cylindrical housing having good electrical and thermal conductivity, there are at least temperature-sensitive particles that melt or soften at a specific temperature, a strong compression spring that pushes the temperature-sensitive particles, an insulating cover that seals the open end of the cylindrical housing, a weak compression spring that abuts against the insulating cover, a first lead that passes through the inner end of the insulating cover as a fixed contact, and a movable contact electrically connected to the first lead and the cylindrical housing. The temperature-sensitive particle-type thermal fuse also includes a second lead disposed on one side of the cylindrical housing. An insulating tube is inserted into the base of the outer end of the first lead, which is the narrowest part between the open end of the cylindrical housing and the first lead, thereby sealing the cylindrical housing, the insulating tube, the insulating cover, and the first lead with a sealing resin while at least covering the base of the outer end of the first lead. The aforementioned insulating tube constitutes an insulating unit and is configured to contact the outer end face of the insulating cover.

[0013] Furthermore, according to another embodiment, a temperature-sensitive particle-type thermal fuse is provided that uses different types of insulating resins as the aforementioned insulating units to perform multi-layer sealing of the sealing resin. Regarding the multi-layer sealing of the sealing resin using these different insulating resins, the multi-layer sealing described herein can be used alone, and it can also be further applied to temperature-sensitive particle-type thermal fuses with the aforementioned insulating tube configuration.

[0014] (Invention Effects)

[0015] The effects obtained according to a representative embodiment of the invention disclosed herein are briefly described below. According to one embodiment of the present disclosure, the power-on and power-off switching of the fuse is made more reliable. Attached Figure Description

[0016] Figure 1 The present invention relates to a temperature-sensitive particle-type temperature fuse 10, with (a) showing a cross-sectional view before operation and (b) showing a cross-sectional view after operation. In (b), the temperature-sensitive material is omitted.

[0017] Figure 2 The present invention relates to a temperature-sensitive particle-type temperature fuse 20, with (a) showing a cross-sectional view before operation and (b) showing a cross-sectional view after operation. The temperature-sensitive material is omitted in (b).

[0018] Figure 3 The present invention relates to a temperature-sensitive particle-type temperature fuse 30, with (a) showing a cross-sectional view before operation and (b) showing a cross-sectional view after operation. The temperature-sensitive material is omitted in (b).

[0019] Figure 4 The present invention relates to a temperature-sensitive particle-type temperature fuse 40, with (a) showing a cross-sectional view before operation and (b) showing a cross-sectional view after operation. The temperature-sensitive material is omitted in (b).

[0020] Figure 5 The present invention relates to a temperature-sensitive particle-type temperature fuse 50, with (a) showing a cross-sectional view before operation and (b) showing a cross-sectional view after operation. The temperature-sensitive material is omitted in (b).

[0021] Figure 6 A cross-sectional view of an existing temperature-sensitive particle-type temperature fuse 60 is shown. Detailed Implementation

[0022] This invention provides a temperature-sensitive particle-type thermal fuse, which, inside a cylindrical shell with good electrical and thermal conductivity, includes at least a temperature-sensitive particle that melts or softens at a specific temperature, a strong compression spring that pushes the temperature-sensitive particle, an insulating cover that closes the open end of the cylindrical shell, a weak compression spring that abuts against the insulating cover, a first lead wire that extends through the inner end of the insulating cover as a fixed contact portion, and a movable contact electrically connected to the first lead wire and the cylindrical shell. The temperature-sensitive particle-type thermal fuse also includes a second lead wire disposed on one side of the cylindrical shell. At the sealing portion of the cylindrical shell, an insulating unit disposed between the open end of the cylindrical shell and the first lead wire at least covers the open end of the cylindrical shell and the outer base of the first lead wire, and a sealing resin is used to seal the cylindrical shell, the first lead wire, and the insulating cover. The aforementioned insulating unit improves the electrical insulation of the narrowest portion of the insulation distance between the cylindrical shell and the first lead wire. The temperature-sensitive particle type temperature fuse of the present invention may further include a disc-shaped pressure plate between the temperature-sensitive particles disposed inside the cylindrical housing and the strong compression spring, and between the strong compression spring and the movable contact.

[0023] In a preferred configuration, such as Figure 1 As shown, a temperature-sensitive particle type thermal fuse 10 is provided, which has at least the following components inside a cylindrical shell 11 with good electrical and thermal conductivity: a temperature-sensitive particle 12 that melts or softens at a specific temperature; a strong compression spring 13 that pushes the temperature-sensitive particle 12; an insulating cover 14 that closes the open end 100 of the cylindrical shell 11; a weak compression spring 15 that abuts against the insulating cover 14 made of heat-resistant insulating material; a first lead 16 that penetrates the inner end of the insulating cover 14 as a fixed contact portion; and a first lead 16 that is connected to the first lead 16. The movable contact 17 electrically connects the wire 16 and the cylindrical housing 11. This temperature-sensitive granular type thermal fuse also includes a second lead 18 disposed on one side of the cylindrical housing 11. An insulating tube 19, made of ceramic, glass, or high-heat-resistant plastic, is inserted between the open end 100 of the cylindrical housing 11 and the outer end base 101 of the first lead 16, at least covering the outer end base 101 of the first lead 16. The cylindrical housing 11, the insulating tube 19, the insulating cover 14, and the first lead 16 are sealed with sealing resin 102. The temperature-sensitive granular type thermal fuse 10 also has a disc-shaped pressure plate 103 between the temperature-sensitive granule 12 and the strong compression spring 13, and between the strong compression spring 13 and the movable contact 17. The insulating tube 19 is configured as a cylindrical body and is made of a heat-resistant insulating material selected from ceramics such as alumina, zirconium oxide, talc, and forsterite, glass, or engineering plastics such as polyimide resin (PI), polyetheretherketone resin (PEEK), and liquid crystal polymer (LCP). The insulating tube 19 constitutes an insulating unit and is positioned to contact the outer end face of the insulating cover 14. By being inserted into the narrowest part of the insulating distance between the cylindrical housing 11 and the first lead 16, the surface distance can be extended, thereby improving electrical insulation. The insulating tube 19 can be as follows... Figure 4 The insulating tube 49 of the temperature-sensitive particle-type thermal fuse 40 shown is deformed such that the inner diameter of at least one opening is smaller than the inner diameter of the other opening.

[0024] Furthermore, according to the present invention, the sealing resin 102 of the temperature-sensitive particle-type temperature fuse 10 can be used to perform multi-layer sealing using different types of insulating resins. For example, such as Figure 2 As shown, a first insulating resin 202a can be provided to cover the area from the outer end face of the insulating cover 24 to the opening end 200 of the cylindrical shell 21, and then a second insulating resin 202b can be used to cover the upper part of the first insulating resin 202a, thereby forming a sealing resin 202. Alternatively, as shown... Figure 3As shown, the outer end face of the insulating cover 34 is covered with a first insulating resin 302a, the upper part of the first insulating resin 302a is covered with a second insulating resin 302b, and the surface of the second insulating resin 302b is further covered with a third insulating resin 302c, thereby forming a sealing resin 302. Furthermore, the insulating tube 39 can be completely covered with the sealing resin 302, or the sealing resin 302 can be used to partially cover the entire circumference of the inner end of the insulating tube 39 and other key areas requiring insulation sealing, such as the inner diameter portion. By using multiple different resins, the resin with high volume resistivity can be focused on the desired location, and the electrical insulation performance can be easily improved with almost no change to the external dimensions of the thermal fuse. In addition, by simultaneously combining resins with different coating properties (including penetration / wetting properties, leveling properties, defoaming properties, etc.), molding properties (shape stability of three-dimensional trays, etc.), and heat resistance, not only can resin coating and three-dimensional molding be highly efficient, but heat resistance can also be easily improved. For example, a first insulating resin 302a with high volume resistivity is applied from the outer end face of the insulating cover 34, including the outer end base 301 of the first lead 36, to the opening end 300 of the cylindrical shell 31. Before curing, an insulating tube 39 is inserted through the first lead 36 and cured against the outer end face of the insulating cover 34 to enhance electrical insulation. Next, a second insulating resin 302b with higher heat resistance and kinematic viscosity is three-dimensionally packaged and cured to enhance heat resistance by embedding it from the outer peripheral surface of the insulating tube 39 to the opening end 300 of the cylindrical shell 31. Finally, a third insulating resin 302c with low kinematic viscosity and heat resistance is applied to the upper end of the insulating tube 39 and impregnated in the gap between the resin inside the tube that has not yet filled the insulating tube 39 and the first lead 36, and then cured. Furthermore, for temperature-sensitive particle-type temperature fuses that utilize multi-layer sealing with insulating resin, the insulating tube 39 can be omitted if necessary. In addition, the third insulating resin 302c can completely cover the outermost surface of the second insulating resin 302b.

[0025] As an example where the aforementioned insulating tube 39 is omitted, there are Figure 5The temperature-sensitive particle type thermal fuse 50 is shown. The temperature-sensitive particle type thermal fuse 50 uses an insulating resin with a higher volume resistivity (corresponding to the first insulating resin 502a below) as the insulating unit. Inside the cylindrical housing 51, which has good electrical and thermal conductivity, it includes at least a temperature-sensitive particle 52 that melts or softens at a specific temperature, a strong compression spring 53 that pushes the temperature-sensitive particle 52, an insulating cover 54 that closes the opening end 500 of the cylindrical housing 51, a weak compression spring 55 that abuts against the insulating cover 54, a first lead 56 that penetrates the inner end of the insulating cover 54 as a fixed contact portion, and a movable contact 57 that electrically connects the first lead 56 and the cylindrical housing 51. The temperature-sensitive particle type thermal fuse 50 also includes... The second lead 58 on one side of the cylindrical housing 51 is covered with a first insulating resin 502a, extending at least from the outer end face of the insulating cover 54 to the opening end 500 of the cylindrical housing 51. The first insulating resin 502a blocks the outer end base 501 of the first lead 56 from the opening end 500 of the cylindrical housing 51. A sealing resin 502 seals the cylindrical housing 51, the insulating tube 59, the insulating cover 54, and the first lead 56. The sealing resin 502 is composed of the first insulating resin 502a covering the outer end face of the insulating cover 54, and a second insulating resin 502b further covering the upper part of the first insulating resin 502a, the outer diameter wall surface of the insulating tube 59, and the outer surface of the opening end 500. Furthermore, the shape of the first insulating resin 502a in the temperature-sensitive particle type temperature fuse according to the invention does not need to be flat, nor does it need to be positioned lower than the opening end 500. Figure 5 As shown, it can be piled up into mountain shapes, etc., and can be formed into any shape.

[0026] The sealing resin involved in this invention can be composed of two or more insulating resins with different Tg (glass transition temperature) and adhesive properties. As a means to ensure that the resin layers, at least at their interfaces, have different Tgs, insulating resins with different Tgs can be combined by changing the curing method of the same resin. For example, after curing a first layer of epoxy resin at room temperature, a second layer of the same epoxy resin can be formed on its surface by heating. Furthermore, resins of different forms can be selected from the group consisting of insulating resins of the following forms: aqueous dispersion (where emulsified resin is dispersed in water), solution (where resin is dissolved in a volatile solvent), solvent-free (where resin is cured by chemical reactions such as polymerization or condensation), and solid system (composed of a solid in the form of blocks, powder, or film). The Tg of each resin, expressed as an absolute temperature, is at least 5 K or more, preferably 20 K or more, to balance mechanical strength and heat resistance. For example, a first layer can be prepared to a Tg of 45°C using a room-temperature curing epoxy resin, and a second layer with a Tg of 100–180°C can be applied on top of it using a heat-curing epoxy resin. Alternatively, the same epoxy resin can be used, but the curing temperature can be changed. For example, the first layer can be cured at room temperature to a Tg of 45°C, and then the same epoxy resin as the first layer can be applied on top and cured at 60°C to form a second layer with a Tg of 55°C. The sealing resin is not particularly limited to any curable resin, but thermosetting silicone resins and epoxy resins can be used, with epoxy resins being particularly preferred.

[0027] When forming the multi-layered sealing resin, a primer coating may be applied at the interfaces of each resin layer or at the interfaces of the cylindrical shell, insulating cover, insulating tube, and first lead to ensure adhesion to the next resin layer to be applied at the corresponding interface. In this case, the sealing resin is formed using two or more resin layers with different Tgs selected from epoxy resins, silicone resins, rubber resins, acrylic resins, or a two-component mixed acrylic resin called SGA (Second Generation Acrylic Adhesive), and a primer coating applied at any interface. For example, a room temperature curing epoxy resin may be applied as the first layer, a primer coating as the second layer, and a silicone resin as the third layer.

[0028] Example

[0029] The temperature-sensitive particle type temperature fuse 10 of Embodiment 1 of the present invention is as follows: Figure 1As shown, inside the cylindrical shell 11 with good electrical and thermal conductivity, there are temperature-sensing particles 12 that melt or soften at a specific temperature, a strong compression spring 13 that pushes the temperature-sensing particles 12, an insulating cover 14 that closes the opening end 100 of the cylindrical shell 11, a weak compression spring 15 that abuts against the insulating cover 14, a first lead 16 with a fixed contact portion extending through the inner end of the insulating cover 14, and a movable contact 17 that electrically connects the first lead 16 and the cylindrical shell 11. The thermocouple 10 has a circular pressure plate 103 between the compression spring 13 and the movable contact 17. It also includes a second lead 18 disposed on one side of the cylindrical housing 11. An aluminum oxide insulating tube 19 is inserted between the open end 100 of the cylindrical housing 11 and the outer end base 101 of the first lead 16. The insulating tube 19 covers the outer end base 101 of the first lead 16, and the cylindrical housing 11, insulating tube 19, insulating cover 14, and first lead 16 are sealed with sealing resin 102. The insulating tube 19 constitutes an insulating unit and is fixed to the outer end face of the insulating cover 14 via sealing resin 102, thereby improving the electrical insulation of the narrowest part of the insulating distance between the cylindrical housing 11 and the first lead 16.

[0030] The temperature-sensitive particle type temperature fuse 20 of Embodiment 2 of the present invention is as follows: Figure 2 As shown, inside the cylindrical shell 21 with good electrical and thermal conductivity, there are temperature-sensing particles 22 that melt or soften at a specific temperature, a strong compression spring 23 that pushes the temperature-sensing particles 22, an insulating cover 24 that closes the opening end 200 of the cylindrical shell 21, a weak compression spring 25 that abuts against the insulating cover 24, a first lead 26 that penetrates the inner end of the insulating cover 24 as a fixed contact part, and a movable contact 27 that electrically connects the first lead 26 and the cylindrical shell 21. There are circular plate-shaped pressure plates 203 between the temperature-sensing particles 22 and the strong compression spring 23, and between the strong compression spring 23 and the movable contact 27. The temperature-sensing particle type temperature fuse 20 is also equipped with... A borosilicate glass insulating tube 29 is inserted between the opening end 200 of the cylindrical shell 21 and the first lead 26 on one side of the second lead 28. The insulating tube 29 is used to block the outer end base 201 of the first lead 26, and the cylindrical shell 21, the insulating tube 29, the insulating cover 24 and the first lead 26 are sealed with sealing resin 202. The sealing resin 202 is formed into two layers: a first insulating resin 202a made of epoxy resin covering the outer end face of the insulating cover 24, and a second insulating resin 202b made of silicone resin further covering the upper part of the first insulating resin 202a and the outer diameter wall surface and the outer surface of the opening end 200 of the insulating tube 29.

[0031] The first insulating resin 202a of the temperature-sensitive particle-type temperature fuse 20 can be formed of silicone resin instead of epoxy resin, and the second insulating resin 202b can be formed of epoxy resin instead of silicone resin.

[0032] The temperature-sensitive particle type temperature fuse 30 of Embodiment 3 of the present invention is as follows: Figure 3 As shown, inside the cylindrical shell 31 with good electrical and thermal conductivity, there are temperature-sensing particles 32 that melt or soften at a specific temperature, a strong compression spring 33 that pushes the temperature-sensing particles 32, an insulating cover 34 that closes the opening end 300 of the cylindrical shell 31, a weak compression spring 35 that abuts against the insulating cover 34, a first lead 36 that passes through the inner end of the insulating cover 35 as a fixed contact part, and a movable contact 37 that electrically connects the first lead 36 and the cylindrical shell 31. There are circular plate-shaped pressure plates 303 between the temperature-sensing particles 32 and the strong compression spring 33, and between the strong compression spring 33 and the movable contact 37. The temperature-sensing particle type temperature fuse 30 also has a second lead 38 disposed on one side of the cylindrical shell 31. An insulating tube 39 made of liquid crystal polymer is inserted between 00 and the first lead 36. The insulating tube 39 is used to cover the outer end base 301 of the first lead 36. The cylindrical shell 31, the insulating tube 39, the insulating cover 34 and the first lead 36 are sealed with sealing resin 302. The sealing resin 302 is formed by covering the outer end face of the insulating cover 34 with a first insulating resin 302a made of room temperature curing epoxy resin, covering the upper part of the first insulating resin 302a, the outer diameter wall of the insulating tube 39 and the outer surface of the opening end 300 of the cylindrical shell 31 with a second insulating resin 302b made of heat curing epoxy resin, and further covering the surface of the second insulating resin 302b, the outer end face and the inner diameter of the insulating tube 39 with a third insulating resin 302c made of silicone resin.

[0033] The second insulating resin 302b of the temperature-sensitive particle-type temperature fuse 30 is formed to cover the outer diameter wall surface of the insulating tube 39 from the open end 300 of the cylindrical housing 31 towards the outward end. At this time, as... Figure 3 As shown, the coating is applied in a manner that leaves a portion of the outer diameter wall of the insulating tube 39 exposed, or in a manner that completely covers the entire outer diameter wall.

[0034] The temperature-sensitive particle-type temperature fuse 40 of Embodiment 4 of the present invention is as follows: Figure 4As shown, inside the cylindrical shell 41 with good electrical and thermal conductivity, there are temperature-sensing particles 42 that melt or soften at a specific temperature, a strong compression spring 43 that pushes the temperature-sensing particles 42, an insulating cover 44 that closes the opening end 400 of the cylindrical shell 41, a weak compression spring 45 that abuts against the insulating cover 44 made of heat-resistant insulating material, a first lead 46 that penetrates the inner end of the insulating cover 44 as a fixed contact portion, and a connection between the first lead 46 and... The movable contact 47 is electrically connected to the cylindrical housing 41. The temperature-sensitive granular type thermal fuse 40 also includes a second lead 48 disposed on one side of the cylindrical housing 41. An insulating tube 49 made of alumina is inserted between the open end 400 of the cylindrical housing 41 and the outer end base 401 of the first lead 46, at least covering the outer end base 401 of the first lead 46. The cylindrical housing 41, the insulating tube 49, the insulating cover 44, and the first lead 46 are sealed with sealing resin 402. The temperature-sensitive granular type thermal fuse 40 also has a disc-shaped pressure plate 403 between the temperature-sensitive granule 42 and the strong compression spring 43, and between the strong compression spring 43 and the movable contact 47. The insulating tube 49 constitutes an insulating unit and is arranged to contact the outer end face of the insulating cover 44, and is inserted to the narrowest part of the insulation distance between the cylindrical housing 41 and the first lead 46, thereby improving electrical insulation. The insulating tube 49 is made of a cylindrical body and is configured such that the inner diameter of one opening is smaller than the inner diameter of the other opening, thereby improving the insulation shielding performance.

[0035] The temperature-sensitive particle type temperature fuse 50 of Embodiment 5 of the invention is as follows: Figure 5As shown, using a first insulating resin 502a with higher volume resistivity in the sealing resin 502 as the insulating unit, inside a cylindrical shell 51 with good electrical and thermal conductivity, there are temperature-sensing particles 52 that melt or soften at a specific temperature, a strong compression spring 53 that pushes the temperature-sensing particles 52, an insulating cover 54 that seals the opening end 500 of the cylindrical shell 51, a weak compression spring 55 that abuts against the insulating cover 54, a first lead 56 that penetrates the inner end of the insulating cover 54 as a fixed contact part, and a movable contact 57 that electrically connects the first lead 56 and the cylindrical shell 51. There are also circular plate-shaped pressure plates 503 between the temperature-sensing particles 52 and the strong compression spring 53, and between the strong compression spring 53 and the movable contact 57. This is a temperature-sensing particle type temperature fuse 5. The 0 also includes a second lead 58 disposed on one side of the cylindrical housing 51. A first insulating resin 502a is applied from the outer end face of the insulating cover 54 to the opening end 500 of the cylindrical housing 51. The first insulating resin 502a covers the outer end base 501 of the first lead 56 starting from the opening end 500 of the cylindrical housing 51. A sealing resin 502 seals the cylindrical housing 51, the insulating tube 59, the insulating cover 54, and the first lead 56. The sealing resin 502 is covered by two layers: the first insulating resin 502a, made of epoxy resin, covering the outer end face of the insulating cover 54, and the second insulating resin 502b, made of silicone resin, sealing the upper part of the first insulating resin 502a and the outer diameter wall surface of the insulating tube 59 and the outer surface of the opening end 500. Furthermore, the first insulating resin 502a need not be flat in shape, nor need it be positioned lower than the opening end 500. Figure 5 As shown, it can be piled up into mountains or other shapes to form any desired form.

[0036] Thus, even resins with low volume resistivity can be utilized through multi-layering such as double or triple coatings. As a result, resins currently considered unsuitable for thermal fuses can be used, allowing for the selection of desired combinations based on properties such as heat resistance, workability, gas barrier properties, water resistance, and adhesion. Furthermore, a smaller amount of resin is required to achieve a given volume resistivity.

[0037] It should be understood that the embodiments disclosed herein are merely illustrative in all respects and not limiting. The scope of the invention is shown not by the foregoing description but by the scope of the claims, and is intended to include all modifications within the scope of the claims and their equivalent meaning.

[0038] (Industrial applicability)

[0039] This invention can be used in contact-separation type temperature fuses with movable contacts that sense abnormal temperatures and cause the contacts to separate, and is particularly suitable for use in temperature-sensing particle type temperature fuses.

[0040] Label Explanation

[0041] Temperature-sensitive granular type thermal fuse 10; cylindrical housing 11; temperature-sensitive granule 12; strong compression spring 13; insulating cover 14; weak compression spring 15; first lead 16; movable contact 17; second lead 18; insulating tube 19; open end 100; outer end base 101; sealing resin 102; pressure plate 103; temperature-sensitive granular type thermal fuse 20; cylindrical housing 21; temperature-sensitive granule 22; strong compression spring 23; insulating cover 24; weak compression spring Spring 25; First lead 26; Movable contact 27; Second lead 28; Insulating tube 29; Open end 200; Outer end base 201; Sealing resin 202; First insulating resin 202a; Second insulating resin 202b; Pressure plate 203; Temperature-sensitive particle type temperature fuse 30; Cylindrical housing 31; Temperature-sensitive particle 32; Strong compression spring 33; Insulating cover 34; Weak compression spring 35; First lead 36; Movable contact 37; Second lead 38 ; Insulating tube 39; Open end 300; Outer end base 301; Sealing resin 302; First insulating resin 302a; Second insulating resin 302b; Third insulating resin 302c; Pressure plate 303; Temperature-sensitive particle type temperature fuse 40; Cylindrical shell 41; Temperature-sensitive particle 42; Strong compression spring 43; Insulating cover 44; Weak compression spring 45; First lead 46; Movable contact 47; Second lead 48; Insulating tube 49; Open end 40 0; outer end base 401; sealing resin 402; pressure plate 403; temperature-sensitive particle type temperature fuse 50; cylindrical shell 51; temperature-sensitive particle 52; strong compression spring 53; insulating cover 54; weak compression spring 55; first lead 56; movable contact 57; second lead 58; insulating tube 59; open end 500; outer end base 501; sealing resin 502; first insulating resin 502a; second insulating resin 502b; pressure plate 503.

Claims

1. A temperature-sensitive granular type temperature fuse, characterized in that, The cylindrical shell, which has good electrical and thermal conductivity, contains: temperature-sensitive particles that melt or soften at a specific temperature; a strong compression spring that pushes the temperature-sensitive particles; an insulating cover that closes the open end of the cylindrical shell; a weak compression spring that abuts against the insulating cover; a first lead wire that passes through the inner end of the insulating cover as a fixed contact; and a movable contact that is electrically connected to the first lead wire and the cylindrical shell. The temperature-sensitive particle-type thermal fuse also includes: The second lead is disposed on one side of the cylindrical shell; Sealing resin is used to cover the outer end base of the first lead to seal the insulating tube, the insulating tube between the opening end of the cylindrical housing and the first lead, the cylindrical housing, the first lead, and the insulating cover. The sealing resin has the following properties: A first sealing resin is filled between the open end of the cylindrical shell and the outer end face of the insulating cover to fix the insulating tube and cover the outer end base of the first lead. The second sealing resin is used to seal the open end of the cylindrical housing, the outer end face of the first lead, and the first sealing resin.

2. The temperature-sensitive granular type thermal fuse according to claim 1, wherein, The insulating tube is made of any of ceramic, glass, or high heat-resistant plastic.

3. The temperature-sensitive granular type thermal fuse according to claim 1 or 2, wherein, The insulating tube is made of a heat-resistant insulating material selected from ceramics, glass, or engineering plastics such as polyimide resin (PI), polyetheretherketone resin (PEEK), and liquid crystal polymer (LCP).

4. The temperature-sensitive granular type thermal fuse according to claim 1 or 2, wherein, The insulating tube is configured such that the inner diameter of one opening is smaller than the inner diameter of the other opening.

5. The temperature-sensitive granular type thermal fuse according to claim 1 or 2, wherein, The first sealing resin is made of a first insulating resin, and the second sealing resin is made of a second insulating resin that is different from the first insulating resin.

6. The temperature-sensitive granular type thermal fuse according to claim 5, wherein, The first sealing resin covers the area from the outer end face of the insulating cover to the opening end of the cylindrical housing, and the second sealing resin covers the upper part of the first sealing resin.

7. The temperature-sensitive granular type thermal fuse according to claim 6, wherein, The first sealing resin or the second sealing resin is formed of epoxy resin or silicone resin.

8. The temperature-sensitive granular type thermal fuse according to claim 5, wherein, It further includes a third sealing resin for covering the surface of the second sealing resin.

9. The temperature-sensitive granular type thermal fuse according to claim 5, wherein, The first sealing resin covers the outer end face of the insulating cover, and the second sealing resin covers the upper part of the first sealing resin, the outer diameter wall of the insulating tube, and the outer surface of the open end of the cylindrical shell. The temperature-sensitive particle-type temperature fuse further includes a third sealing resin covering the surface of the second sealing resin and the outer end face and inner diameter portion of the insulating tube.

10. The temperature-sensitive granular type thermal fuse according to claim 8 or 9, wherein, The first sealing resin is composed of room temperature curing epoxy resin, the second sealing resin is composed of heat curing epoxy resin, and the third sealing resin is composed of silicone resin.

11. The temperature-sensitive granular type thermal fuse according to any one of claims 6 to 9, wherein, The sealing resin is composed of two or more insulating resins with different glass transition temperatures (Tg).

12. The temperature-sensitive granular type thermal fuse according to claim 11, wherein, The first sealing resin and the second sealing resin have different Tg values ​​by being cured using different curing methods.

13. The temperature-sensitive granular type thermal fuse according to claim 11, wherein, The Tg, expressed as absolute temperature, is at least 5K or higher.

14. The temperature-sensitive granular type thermal fuse according to claim 12, wherein, The Tg, expressed as absolute temperature, is at least 5K or higher.

15. The temperature-sensitive granular type thermal fuse according to claim 11, wherein, The first sealing resin and the second sealing resin are selected from the group consisting of insulating resins with different morphologies.

16. The temperature-sensitive granular type thermal fuse according to claim 15, wherein, The form is composed of any of the following: an aqueous dispersion in which the emulsified resin is dispersed in water; a solution in which the resin is dissolved in a volatile solvent; a solvent-free form that is cured by chemical reactions such as polymerization and condensation; or a solid system in the form of blocks, powders, or films.

17. The temperature-sensitive granular type thermal fuse according to any one of claims 6 to 9, wherein, A primer coating is provided at the first interface of the first sealing resin and the second sealing resin, or at the second interface of the cylindrical shell, the insulating cover, the insulating tube, and the first lead to be sealed, in order to ensure adhesion to the next resin layer to be applied to the first interface or the second interface.

18. The temperature-sensitive granular type thermal fuse according to claim 17, wherein, The sealing resin is formed by using two or more resin layers with different Tgs selected from epoxy resin series, silicone resin, rubber series, acrylic resin series, and a two-component mixed acrylic resin known as second-generation acrylic ester adhesive SGA, and a primer coating disposed at a third interface between the two resin layers.

19. The temperature-sensitive granular type thermal fuse according to claim 6, wherein, The insulating tube is made of the first sealing resin.

20. The temperature-sensitive granular type thermal fuse according to claim 11, wherein, The Tg, expressed as absolute temperature, is at least 20 K or higher.

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