JP2017220386A - Thermosensitive pellet type thermal fuse - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosensitive pellet type thermal fuse which has a strength lead structure in a bent part and a twisted part and prevents disconnection of the lead.SOLUTION: A thermosensitive pellet type thermal fuse comprises: a thermosensitive pellet 12 which is melted or softened in an inner part of a cylindrical conductive case 11 at a predetermined temperature; a strong compression spring 13 that presses the thermosensitive pellet; an insulation busing 14 that is inserted and attached to an opening end of the cylindrical case; a weak compression spring 15 that is contacted to the insulation bushing; a conductive first lead 16 in which an inner end to which the insulation bushing is penetrated is set as a contact point; a movable contact point 17 that is electrically connected to the first lead and the cylindrical case; a conductive second lead 18 that is arranged on one end of the cylindrical case; and an insulation sealing member 70 that seals the opening end of the cylindrical case from an external end surface of the insulation bushing. The first lead includes a flange part or a large-diameter part 100 contacted to the outer end of the insulation bushing, and further includes an engaging part 200 in the inner part in which the insulation bushing is penetrated.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a temperature-sensitive pellet type thermal fuse that detects an overheat of an electric device and interrupts a circuit.

  In household electrical appliances or industrial electrical / electronic equipment, thermal fuses are used as protective parts that sense the temperature of the equipment and quickly shut down the circuit in the event of abnormal overheating. The thermal fuse is mounted on a product such as a home appliance, a portable device, a communication device, an office device, an in-vehicle device, an AC adapter, a charger, a motor, or a battery. In general, there are various types of thermal fuses with rated current values ranging from about 0.5 A to about 15 A, and temperature sensitive pellet type thermal fuses are particularly preferably used for high current ratings of 6 A or more. As one of typical forms of the temperature-sensitive pellet type thermal fuse, for example, as shown in Patent Document 1 or Patent Document 2, a cylindrical metal case and first leads disposed at both ends of the metal case And a temperature sensitive pellet disposed in contact with the second lead, and a movable contact that is in contact with the first lead via the temperature sensitive pellet and is constantly biased in the separating direction. When the temperature of the mounted electrical equipment exceeds a predetermined temperature, the temperature-sensitive pellet melts or softens so that the movable contact is separated from the first lead by the urging force and the circuit is cut off. There is a fuse. The temperature-sensitive pellet type thermal fuse is connected to the power line of the electric device and is arranged at a location where it is desired to detect a temperature abnormality. The temperature-sensitive pellet is solid at normal temperature, and at this time, the movable contact is pressed against the inner end of the case of the first lead by the biasing force. Therefore, the first lead-metal case-movable contact-second lead is held in a conductive state. Then, for example, when the temperature of the installation location reaches the operating temperature of the temperature-sensitive pellet type thermal fuse due to abnormal energization such as a short circuit of the wiring, the temperature-sensitive pellet is melted and the movable contact is pressed against the end of the first lead. Since the biasing force is released, the movable contact is separated from the inner end of the case of the first lead, and the conduction between the first lead and the second lead is interrupted. Stopping power supply and distribution to electrical equipment prevents overheating damage or ignition accidents of electrical equipment.

Japanese Patent Laid-Open No. 01-154422 Registration No. 3161636 Japanese Utility Model Publication No. 61-151235

  A conventional temperature-sensitive pellet type temperature fuse has a temperature-sensitive pellet that melts or softens at a predetermined temperature in a metal cylindrical case, a strong compression spring that presses the temperature-sensitive pellet, and an open end of the cylindrical case. An insulating bushing inserted into the insulating bushing, a weak compression spring in contact with the insulating bushing, a first lead having an inner end penetrating the insulating bushing as a contact portion, and the first lead and the cylindrical case. And a second lead disposed at one end of the cylindrical case. The first lead of this thermal fuse is provided with a flange at the inner end in advance so as not to be pulled out when pulled, and after the first lead is inserted into the insulating bushing so that the insulating bushing comes into contact with this flange, the insulating lead is insulated. The first lead is caulked on the outer end side of the bushing to prevent the lead from being pushed into the cylindrical case. (For example, see Patent Document 3)

  However, since the conventional temperature-sensitive pellet type thermal fuse is fixed by caulking the lead at the outer end of the insulating bushing, when the external force such as bending or twisting is applied to the first lead, the diameter is reduced by caulking. The lead diameter is reduced because the lead is caulked at the outer end of the insulating bushing, which is a fulcrum for bending and twisting, even when the first lead is subjected to strong bending or twisting. There is a drawback that bending and twisting tend to concentrate on the crimped portion.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a lead structure that is resistant to bending and twisting in a temperature-sensitive pellet type thermal fuse, and to prevent disconnection occurring in a first lead of the temperature-sensitive pellet type thermal fuse.

  According to the present invention, at least inside the conductive cylindrical case, a temperature-sensitive pellet that melts or softens at a predetermined temperature, a strong compression spring that presses the temperature-sensitive pellet, and an insertion end of the cylindrical case. An insulating bushing, a weak compression spring in contact with the insulating bushing, a conductive first lead having an inner end penetrating the insulating bushing as a contact portion, and the first lead and the cylindrical case. A movable contact; a conductive second lead disposed at one end of the cylindrical case; and an insulating sealing material that seals the open end of the cylindrical case from the outer end surface of the insulating bushing. The lead has a flange portion or a large diameter portion that comes into contact with the outer end of the insulating bushing, and the first lead further has a locking portion in an inner portion that penetrates the insulating bushing. Thermal fuse provided That. In the temperature-sensitive pellet type thermal fuse of the present invention, the locking portion of the first lead is provided not on the outer end portion of the insulating bushing that tends to be a fulcrum when bending or twisting is applied, but on the inner portion of the insulating bushing. The locking portion may be any fixing means as long as the first lead can be configured not to be pulled out from the insulating bushing. For example, a protrusion formed by plastic deformation of the inner portion of the first lead or an inner portion of the first lead. A method of preventing the first lead from coming off by a protrusion, ring or pin attached to the side, or by filling a soldering material or an adhesive into the dent or notch provided in the inner part of the insulating bushing. A method of fixing an insulating bushing on the side, or a protrusion provided by being melted and deformed by local heating means such as laser irradiation can be used. This protrusion may protrude over the entire circumference of the peripheral wall of the lead shaft, or a part of the peripheral wall may protrude partially.

  In the temperature-sensitive pellet type thermal fuse of the present invention, since the portion having a small lead diameter is arranged inside the insulating bushing where no mechanical stress is applied, the durability of the lead is remarkably improved. That is, in the first lead of the present invention, the flange portion or the large diameter portion provided on the lead is abutted and fixed to the outer end of the insulating bushing, so there is no portion where the lead diameter is reduced by caulking or the like in the middle of the lead. Furthermore, since the first lead is deformed and locked, not the outer end portion of the insulating bushing, which becomes a fulcrum of bending, but the inner end portion is deformed and locked, the periphery of the lead shaft of the locking portion is sheathed and held by the insulating bushing hole. The portion is not directly exposed to bending. In addition, a lead wire having a diameter larger than that of a conventional temperature-sensitive pellet type thermal fuse can be used.

1 is a partial cross-sectional view of a temperature-sensitive pellet type thermal fuse 10 according to the present invention. The fragmentary sectional view of the temperature sensitive pellet type thermal fuse 20 concerning this invention is shown. 1 is a partial cross-sectional view of a temperature sensitive pellet type thermal fuse 30 according to the present invention. The fragmentary sectional view of the temperature sensitive pellet type thermal fuse 40 which concerns on this invention is shown. The fragmentary sectional view of the temperature sensitive pellet type thermal fuse 50 which concerns on this invention is shown.

  According to the present invention, inside a conductive cylindrical case, a temperature-sensitive pellet that melts or softens at a predetermined temperature, a strong compression spring that presses the temperature-sensitive pellet, and an insulation that is inserted into the open end of the cylindrical case. A bushing, a weak compression spring in contact with the insulating bushing, a conductive first lead having an inner end penetrating the insulating bushing as a contact portion, and a movable contact electrically connected to the first lead and the cylindrical case And a conductive second lead disposed at one end of the cylindrical case, and an insulating sealing material that seals the opening end of the cylindrical case from the outer end surface of the insulating bushing. There is provided a temperature sensitive pellet type thermal fuse having a flange portion or a large diameter portion at an outer end of the insulating bushing and further having a locking portion at an inner portion of the first lead penetrating the insulating bushing. The Furthermore, in the temperature-sensitive pellet type thermal fuse, the first lead has an engaging portion obtained by deforming at least a part of the inner peripheral wall, and the engaging portion is housed in a retaining frame provided at the inner end portion of the insulating bushing. A temperature sensitive pellet type thermal fuse is provided.

  For example, as shown in FIG. 1, the temperature-sensitive pellet type thermal fuse 10 of the present invention is further provided with a more conductive coating as required on a base material selected from copper, iron, copper alloy, and iron alloy. Inside the cylindrical case 11, two copper alloy or iron alloy metal plates 60, a temperature sensitive pellet 12 made of a chemical agent or a thermoplastic resin that melts or softens at a predetermined temperature, and the temperature sensitive pellet 12 are pressed. A strong compression spring 13, an insulating bushing 14 that is inserted into and fixed to the opening end of the cylindrical case 11, a weak compression spring 15 that is in contact with the insulating bushing 14, and an insulating bushing 14. A first lead 16 in which a base material selected from copper, iron, a copper alloy, and an iron alloy having an inner end penetrating the contact point as a contact portion is further provided with a better conductive film as required, and the first lead 16. The lead 16 and the cylindrical case 11; A better conductive coating is applied to the base material selected from copper, iron, copper alloy, and iron alloy disposed at one end of the cylindrical case 11 and the electrically conductive movable contact 17 connected in air. Furthermore, the second lead 18 provided and an insulating sealing material 70 that seals the opening end of the cylindrical case 11 from the outer end surface of the insulating bushing 14, the first lead 16 is provided at the outer end of the insulating bushing 14. The first lead 16 is a locking portion 200 that is deformed so as to project part or all of its axial peripheral wall surface at an inner portion that penetrates the insulating bushing 14 and has a flange portion 100 that comes into contact with the bushing 14. Have If necessary, the first lead 16 may be sealed by inserting an insulating insulating tube 80 such as ceramic or plastic.

  Further, as shown in FIG. 2, the temperature-sensitive pellet type thermal fuse 20 of the present invention is further provided with a more conductive coating as required on a base material selected from copper, iron, copper alloy, and iron alloy. Inside the cylindrical case 21, two copper alloy or iron alloy metal plates 60, a temperature sensitive pellet 22 made of a chemical agent or a thermoplastic resin that melts or softens at a predetermined temperature, and the temperature sensitive pellet 22 are pressed. A strong compression spring 23, an insulating bushing 24 that is inserted into and fixed to the opening end of the cylindrical case 21, a weak compression spring 25 that is in contact with the insulating bushing 24, and an insulating bushing 24. A first lead 26 further provided with a better conductive coating as required on a base material selected from copper, iron, a copper alloy, and an iron alloy with the inner end penetrating the contact portion as a contact portion; Lead 26 and cylindrical case 21 and electrical If necessary, a more conductive coating is further applied to the base material selected from copper, iron, copper alloy, and iron alloy disposed on one end of the cylindrical case 21. The second lead 28 provided and an insulating sealing material 70 that seals the opening end of the cylindrical case 21 from the outer end surface of the insulating bushing 24, and the first lead 26 is provided at the outer end of the insulating bushing 24. The first lead 26 is an inner portion that has a large diameter portion 100 that abuts and further penetrates the insulating bushing 24, and the first lead 26 is deformed so as to project part or all of its axial wall surface. Have The locking portion 200 is provided at the inner portion of the insulating bushing 24, and any fixing means may be used as long as it can be locked so that the first lead 26 does not come off from the inner end thereof. It may be fixed by protrusions, rings or pins formed on the inner part, or solder material or adhesive is poured into the dents and notches provided on the inner part of the insulating bushing, and then fixed. One lead inner part may be fixed to the insulating bushing, or alternatively, the insulating bushing may be fixed by a protrusion provided by melting and deforming the plating layer or base material of the first lead by local heating means such as laser irradiation. May be. Further, if necessary, the first lead 26 may be sealed by inserting an insulating soot tube 80 such as ceramic or plastic. Further, the second lead 28 may have the same diameter as the first lead 26.

  Further, as shown in FIG. 3, the temperature-sensitive pellet type thermal fuse 30 of the present invention is a cylinder in which a base material selected from copper, iron, a copper alloy, and an iron alloy is further provided with a more conductive film as required. Two metal plates 60 made of copper alloy or iron alloy, a temperature sensitive pellet 32 made of a chemical agent or thermoplastic resin that melts or softens at a predetermined temperature, and the temperature sensitive pellet 32 A strong compression spring 33, an insulating bushing 34 that is inserted into and fixed to the opening end of the cylindrical case 31, a weak compression spring 35 that is in contact with the insulating bushing 34, and an insulating bushing 34. A first lead 36 further provided with a better conductive coating as required on a base material selected from copper, iron, copper alloy, and iron alloy with the inner end penetrating the contact portion as a contact portion; The lead 36 and the cylindrical case 31; A better conductive coating is applied to the base material selected from copper, iron, copper alloy, and iron alloy disposed on one end of the cylindrical case 31 and the electrically conductive movable contact 37 connected in air. Furthermore, the second lead 38 provided and an insulating sealing material 70 that seals the opening end of the cylindrical case 31 from the outer end surface of the insulating bushing 34 are provided. The first lead 36 is an outer end of the insulating bushing 34. The first lead 36 is an inner portion that has a flange portion 100 that is in contact with the insulating bushing 34 and penetrates the insulating bushing 34, and the first lead 36 is deformed so as to project part or all of its axial peripheral wall surface. Have The locking part 200 may be housed in a retaining frame 90 made up of a peripheral wall and a slit provided at the inner end of the insulating bushing 34. As long as the locking part 200 is provided in the inner part of the insulating bushing 34 and can be locked so that the first lead 36 does not come out from the inner end part, any fixing means may be used. For example, it may be fixed by a protrusion, ring or pin formed on the inner part of the first lead, or a solder material or an adhesive is poured into a dent or notch provided on the inner part of the insulating bushing. The inner part of the first lead and the insulating bushing may be fixed by hardening, or alternatively, the protrusion provided by melting and deforming the plating layer or base material of the first lead by local heating means such as laser irradiation. The insulating bushing may be fixed by Furthermore, a rod 80 made of an insulating material such as ceramic or plastic may be inserted into the first lead 36 and sealed as necessary.

  A temperature-sensitive pellet type thermal fuse 10 of Example 1 shown in FIG. 1 is melted or softened at a predetermined temperature with two metal plates 60 made of copper alloy inside a cylindrical case 11 made of silver-plated copper alloy. A temperature-sensitive pellet 12 made of polyolefin resin, a strong compression spring 13 that presses the temperature-sensitive pellet, and a ceramic insulating bushing 14 that is inserted into the opening end of the cylindrical case 11 and fixed by caulking the opening end inward. A weak compression spring 15 in contact with the insulating bushing 14, a silver-plated copper material first lead 16 with the inner end penetrating the insulating bushing 14 as a contact portion, the first lead 16 and the cylindrical case 11, a silver alloy movable contact 17 electrically connected to 11, a silver-plated copper alloy material second lead 18 disposed at one end of the cylindrical case 11, and an open end of the cylindrical case 11 from the outer end surface of the insulating bushing 14. The first lead 16 has a flange portion 100 that contacts the outer end of the insulating bushing 14, and the first lead 16 is an inner portion that penetrates the insulating bushing 14. It has the latching | locking part 200 which consists of the processus | protrusion which crimped to the wing type. The first lead 16 is sealed by inserting a ceramic rod 80.

  The temperature-sensitive pellet type thermal fuse 20 of Example 2 shown in FIG. 2 is melted or softened at a predetermined temperature with two stainless steel metal plates 60 inside a cylindrical case 21 made of silver-plated copper alloy. A temperature-sensitive pellet 22 made of polyolefin resin, a strong compression spring 23 that presses the temperature-sensitive pellet 22, and an insulating bushing made of ceramic that is inserted into the opening end of the cylindrical case 21 and fixed by caulking the opening end inward. 24, a weak compression spring 25 in contact with the insulating bushing 24, a first lead 26 made of silver-plated copper with the inner end penetrating the insulating bushing 24 as a contact portion, the first lead 26 and the cylindrical shape A silver alloy movable contact 27 electrically connected to the case 21, a silver-plated copper alloy material second lead 28 disposed at one end of the cylindrical case 21, and the cylindrical case 2 from the outer end surface of the insulating bushing 24. The first lead 26 has a large-diameter portion 100 that abuts against the outer end of the insulating bushing 24, and an inner portion that penetrates the insulating bushing 24. The first lead 26 has a locking portion 200 made of a projection caulked into a wing shape.

  The temperature-sensitive pellet type thermal fuse 30 of Example 3 shown in FIG. 3 is melted or softened at a predetermined temperature with two stainless steel metal plates 60 inside a cylindrical case 31 made of silver-plated iron-nickel alloy. A thermosensitive pellet 32 made of a chemical agent, a strong compression spring 33 that presses the thermosensitive pellet 32, and a ceramic insulation that is inserted into the opening end of the cylindrical case 31 and fixed by caulking the opening end inward. A bushing 34, a weak compression spring 35 in contact with the insulating bushing 34, a first lead 36 made of silver-plated iron-nickel alloy with the inner end penetrating the insulating bushing 34 as a contact portion, and the first lead 36 And a silver alloy movable contact 37 electrically connected to the cylindrical case 31, a second lead 38 of silver-plated iron-nickel alloy material disposed at one end of the cylindrical case 31, and an outer end of the insulating bushing 34. The first lead 36 has a flange portion 100 that contacts the outer end of the insulating bushing 34, and further penetrates the insulating bushing 34. The first lead 36 is partially melted by irradiating the first lead 36 with a laser from the slit opening at the inner part, and has a locking part 200 made of a cross-shaped protrusion provided. Reference numeral 200 denotes a peripheral wall provided at the inner end of the insulating bushing 34 and a slit-like retaining frame 90. The first lead 36 is sealed by inserting a ceramic rod 80.

  Here, the retaining frame 90 is provided at the inner end portion of the insulating bushing 34 in order to suppress the arc discharge from the locking portion 200, and any shape can be used as long as it can wrap around all or part of the locking portion 200. It may be a thing. For example, the periphery of the locking part 200 may be surrounded by a peripheral wall, or a slit or notch (regardless of shape) is provided at the inner end of the insulating bushing 34 so that the locking part 200 is accommodated in the slit or notch. Also good.

  The temperature-sensitive pellet type thermal fuse 40 of Example 4 shown in FIG. 4 is melted or softened at a predetermined temperature with two stainless steel metal plates 60 inside a cylindrical case 41 made of silver-plated copper alloy. Temperature-sensitive pellets 42 made of polyolefin resin, a strong compression spring 43 that presses the temperature-sensitive pellets 42, and an insulating bushing made of ceramic that is inserted into the opening end of the cylindrical case 41 and fixed by caulking the opening end inward. 44, a weak compression spring 45 in contact with the insulating bushing 44, a silver-plated copper material first lead 46 with the inner end penetrating the insulating bushing 44 as a contact portion, the first lead 46 and the cylindrical shape A silver alloy movable contact 47 electrically connected to the case 41, a silver-plated copper alloy material second lead 48 disposed at one end of the cylindrical case 41, and the cylindrical case 4 from the outer end surface of the insulating bushing 44. The first lead 46 has a large-diameter portion 100 that comes into contact with the outer end of the insulating bushing 44, and an inner portion that penetrates the insulating bushing 44. Then, the first lead 46 is irradiated with a laser from the opening of the slit 90 so that the silver plating layer of the first lead 46 is partially melted to have a locking portion 200 made of a cross-shaped protrusion. The locking portion 200 is housed in a peripheral wall provided at the inner end of the insulating bushing 44 and a slit-like retaining frame 90.

  The temperature-sensitive pellet type thermal fuse 50 of Example 5 shown in FIG. 5 is melted or softened at a predetermined temperature with two stainless steel metal plates 60 inside a cylindrical case 51 made of silver-plated copper alloy. A temperature-sensitive pellet 52 made of polyolefin resin, a strong compression spring 53 that presses the temperature-sensitive pellet 52, and an insulating bushing made of ceramic that is inserted into the opening end of the cylindrical case 51 and fixed by caulking the opening end inward. 54, a weak compression spring 55 in contact with the insulating bushing 54, a first lead 56 of a silver-plated copper material with the inner end penetrating the insulating bushing 54 as a contact portion, and the first lead 56 and the cylindrical shape A silver alloy movable contact 57 electrically connected to the case 51, a silver-plated copper alloy material second lead 58 disposed at one end of the cylindrical case 51, and the cylindrical case 5 from the outer end surface of the insulating bushing 54. The first lead 56 has a large-diameter portion 100 that comes into contact with the outer end of the insulating bushing 54, and is provided at the inner portion of the insulating bushing 54. An engaging portion 200 made of a protrusion formed by filling a ring-shaped groove formed between the retaining frame 90 made of dents and the first lead 56 inserted into the retaining frame 90 and the insulating bushing 54 with a solder material. Have. Therefore, the locking portion 200 is fixed by being embedded in a retaining frame 90 provided with a protrusion at the inner end portion of the insulating bushing 54. The solder material can be changed to an adhesive as necessary.

  INDUSTRIAL APPLICABILITY The present invention can be used for a temperature-sensitive pellet type thermal fuse that has a movable contact and senses an abnormal temperature to open the contact.

10, 20, 30 ... temperature-sensitive pellet type thermal fuse,
11, 21, 31 ... cylindrical case,
12, 22, 32 ... temperature-sensitive pellets,
13, 23, 33 ... strong compression spring,
14, 24, 34 ... insulating bushings,
15, 25, 35 ... weak compression spring,
16, 26, 36 ... first lead,
17, 27, 37 ... movable contacts,
18, 28, 38 ... second lead,
60 ... metal plate,
70 ... sealing material,
80 ...
90 ... retaining frame (peripheral wall and slit),
100 ... flange part or large diameter part,
200: A locking portion.

Claims (6)

  At least a temperature-sensitive pellet that melts or softens at a predetermined temperature inside the conductive cylindrical case, a strong compression spring that presses the temperature-sensitive pellet, and an insulating bushing that is inserted into the opening end of the cylindrical case A weak compression spring in contact with the insulating bushing, a conductive first lead having an inner end penetrating the insulating bushing as a contact portion, and a movable contact electrically connected to the first lead and the cylindrical case And a conductive second lead disposed at one end of the cylindrical case, and an insulating sealing material that seals the open end of the cylindrical case from the outer end surface of the insulating bushing, The first lead has a flange portion or a large-diameter portion that abuts on an outer end of the insulating bushing, and the first lead further has a locking portion in an inner portion that penetrates the insulating bushing. Temperature sensitive pellets Mold temperature fuse.   2. The temperature-sensitive pellet according to claim 1, wherein the first lead is further provided with a better conductive coating as necessary on a base material selected from copper, iron, a copper alloy, and an iron alloy. Mold temperature fuse.   The locking portion includes an locking portion that is an inner portion that penetrates the insulating bushing and is deformed so as to project part or all of the axial circumferential wall surface of the first lead. The temperature-sensitive pellet type thermal fuse according to claim 1 or 2.   3. The feeling according to claim 1, wherein the locking portion includes a projection provided by melting and deforming the highly conductive coating of the first lead or the base material by local heating means. Hot pellet type thermal fuse.   The temperature-sensitive pallet type thermal fuse according to claim 1 or 2, wherein the locking portion is made of a solder material or an adhesive. The temperature-sensitive pellet type thermal fuse according to any one of claims 1 to 6, wherein the insulating bushing is provided with a retaining frame that accommodates the locking portion.

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