Contact material for thermal cut-out, movable contact and thermal cut-out of the thermal sensitive pellet type

Abstract

The present disclosure relates to a contact material of a thermal fuse, a movable contact, and a thermal sensitive pellet type thermal fuse. The thermal sensitive pellet type thermal fuse includes, inside a cylindrical case having electrical conductivity, thermal sensitive pellets that melt or soften at a certain temperature, a strong compression spring configured to press the thermal sensitive pellets, an insulating cover that closes the cylindrical case, a weak compression spring that abuts against the insulating cover, a first lead wire that extends through the insulating cover and includes an inner end as a fixed contact, a movable contact that is electrically connected to the first lead wire and the cylindrical case, a sealing resin that is disposed to surround a portion of the first lead wire, cover an outer end portion of the insulating cover, and seal an open end portion of the cylindrical case, and a second lead wire that is disposed at one end of the cylindrical case. The movable contact includes an electrically conductive base material and an electrically conductive member that covers a predetermined surface of the electrically conductive base material.

Description

Technical Field

[0001] This invention relates to a contact material made of a composite material having a multilayer structure and a thermistor-sensitive particle-type thermal fuse using the contact material. Background Technology

[0002] Thermal fuses have been used to protect household or industrial electronic and electrical equipment from damage caused by overheating. Thermal fuses are used as protective components in a wide range of household appliances, portable devices, communication equipment, office equipment, vehicle equipment, AC adapters, chargers, motors, batteries, and other electronic components, accurately detecting the temperature of the device and promptly disconnecting the circuit in case of abnormal overheating. Generally, thermal fuses have a wide range of rated currents from approximately 0.5A to 15A. However, particularly for high currents of 6A or greater, it is appropriate to utilize thermistor-type thermal fuses, which include contacts and are configured to separate upon detection of an abnormal temperature. Detailed information on thermistor-type thermal fuses is available in various forms. For example, the thermistor-type thermal fuse described in Patent Document 1 includes an Ag-plated metal housing, a pair of Ag-plated leads, insulating material, two compression springs (one weak and one strong), a sliding contact, and a thermistor as its main components, and the sliding contact is movable when in contact with the inner surface of the Ag-plated metal housing. A weak compression spring is positioned between the sliding contact and the insulating material, while a strong compression spring is positioned between the sliding contact and the thermosensitive material. Both springs are normally compressed, with the strong spring being stronger than the weak spring. Therefore, the sliding contact is pressed against the insulating material and becomes conductive. Thus, when a lead is connected to wiring in electronic equipment, current flows from that lead through the sliding contact, to the metal housing, and then to the other lead. Organic reagents, thermoplastic resins, etc., can be used for the thermosensitive material. When a predetermined operating temperature is reached, the thermosensitive material melts or softens and deforms under the load from the compression springs. Therefore, when the electronic equipment connected to the thermal fuse overheats and reaches the predetermined operating temperature, the thermosensitive material deforms, the corresponding compression spring is unloaded, the compression of the other compression spring is released in response to its extension, and the extension causes the sliding contact to move upon contact with the inner surface of the metal housing, thereby interrupting electrical conduction. By connecting a thermistor-type thermal fuse with this function to the wiring of electronic devices, damage to the main body of the device, fire, etc., caused by abnormal overheating of the device can be prevented.

[0003] As sliding contacts for thermistor-sensitive granular thermal fuses, sliding contacts are typically obtained by rolling a metal material into a thin sheet shape and pressing the sheet to form a recessed star shape. In the related field, sliding contacts for thermistor-sensitive granular thermal fuses are used because it is necessary to prevent welding of the contacts caused by arc discharge during separation operations. This sliding contact is obtained by internally oxidizing an internally oxidizable Ag alloy containing Cu or the like in a pressure oxidation furnace to disperse oxide particles, such as Cu oxide particles, in the Ag substrate on the surface layer of the contact material. Furthermore, Patent Document 2 discloses a sliding contact obtained by plating a single layer of ultrathin Ag onto the surface of a Cu substrate.

[0004] Reference List

[0005] Patent documents

[0006] Patent document 1: WO 2003 / 009323 A1

[0007] Patent document 2: JP 3161636 U Summary of the Invention

[0008] Technical issues

[0009] In related fields, sliding contacts utilizing internally oxidizable Ag alloy materials are contact materials that selectively oxidize the precious metal in an alloy of an Ag substrate and a precious metal using an internal oxidation method. The oxide particles are then dispersed and encapsulated in the surface layer, thereby preventing the contacts from being welded or adhered. However, since the surface is predominantly soft Ag, this material is prone to contact welding and adhesion. Furthermore, due to the use of Ag, this contact material can be considered relatively expensive. Sliding contacts require elasticity to allow maintaining electrical contact with the metal housing, and mobility to allow smooth sliding without welding or adhesion. The idea described in Patent Document 2 is a low-cost contact material proposed to improve this problem. However, when the contact portion is formed solely from a thin film of Ag plating material on a Cu substrate as described herein, the Ag plating film is too thin and easily damaged by arc discharge during separation operations, exposing the Cu material surface and leading to contact adhesion. Another drawback is that if exposed to heat for extended periods, the Ag layer on the surface can diffuse and disappear into the Cu substrate over time, increasing the fuse resistance and causing welding during contact separation. Furthermore, the annealing effect reduces the spring force that presses the sliding contact against the sliding surface, further increasing the fuse resistance. It's important to note that "adhesion" refers to the contact parts pressing against each other due to prolonged exposure to heat, becoming stuck or adhered, and no longer moving; "welding" refers to the contact parts being welded together by the electric arc generated during separation and no longer moving.

[0010] The object of the present invention is to provide a contact material for a thermal fuse and a thermistor particle type thermal fuse using the contact material. The contact material uses an inexpensive substrate containing as little precious metal as possible, such as Ag substrate, and can adjust the elasticity for maintaining electrical contact with the metal housing, and can prevent welding and adhesion to the leads, while suppressing the increase of contact resistance value. Summary of the Invention

[0012] According to the present invention, a contact material for a thermal fuse is provided, which is used to form a movable contact of a thermistor-sensitive granular thermal fuse. The contact material includes a conductive substrate and a conductive member, the conductive member being disposed to cover a predetermined area of ​​the surface of the conductive substrate. The conductive member is disposed at least in contact portions with the fixed contact and cylindrical housing of the thermal fuse, and is made of a material having a Young's modulus and stiffness different from those of the conductive substrate. This contact material can be applied to the sliding contact of a thermistor-sensitive granular thermal fuse. For example, the contact material can be used in a star-shaped movable contact of a thermal fuse. The conductive member can be partially disposed in an overlay extending at least on one side of the conductive substrate in contact with the fixed contact or cylindrical housing, or disposed in an insert fitting the conductive member into at least one side of the conductive substrate in contact with the fixed contact or cylindrical housing. By combining the conductive member with the conductive substrate through the overlay or insert, materials with different Young's moduli can be combined, and the thickness of the contact material itself can be varied as needed. This makes it easy to adjust the spring characteristics of the contact material to the desired range. It should be noted that the overlying or embedded surface does not necessarily need to be flat to be flush with the conductive substrate surface, and can be configured to be non-uniform due to the overlying or embedded portion. However, the movable contact according to the invention can have any shape and is not limited to the illustrated star shape, as long as the movable contact maintains the elasticity to allow electrical contact with the metal housing, and the mobility to allow smooth sliding without welding or adhesion at predetermined voltage / current ratings.

[0013] According to another aspect of the invention, such as Figure 4 As shown, a thermistor-type thermal fuse is provided, wherein the abutment surface between a fixed contact and a movable contact disposed on the inner end face of the lead wire is a contact separation surface. The thermistor-type thermal fuse includes, inside a cylindrical housing 41 having good electrical and thermal conductivity: a thermistor-sensitive particle 42 that melts or softens at a specific temperature; a strong compression spring 43 configured to press the thermistor-sensitive particle 42; an insulating cover 44 that closes the opening of the cylindrical housing 41; a weak compression spring 45 abutting against the insulating cover 44; a first lead wire 46 extending through the insulating cover 44 and including an inner end of a fixed contact 400; a movable contact 47 electrically connected to the first lead wire 46 and the cylindrical housing 41; a sealing resin 48 disposed around a portion of the first lead wire 46, covering the outer end portion of the insulating cover 44 and sealing the open end portion of the cylindrical housing 41; and a second lead wire 49 disposed at one end of the cylindrical housing 41. Figure 2As shown, the movable contact 47 includes a conductive substrate 21 and conductive members 22 (22a, 22b) covering a predetermined surface of the conductive substrate 21. The conductive members 22 are disposed at least at the contact portions with the fixed contact 400 and the inner wall surface of the cylindrical housing 41, and are made of a material having a Young's modulus and rigidity different from those of the conductive substrate 21. The conductive members of the movable contact can be provided by an overlay extending on a flat surface of the conductive substrate at the contact portions with the fixed contact and with the inner wall surface of the cylindrical housing on one side of the conductive substrate, or by an insert fitting the conductive members into a cavity disposed in the conductive substrate. The movable contact is composed of a conductive substrate and conductive members, such that the elasticity can be changed according to position by a combination of materials with different Young's moduli, or that the thickness of each of the aforementioned materials can be changed as needed. Therefore, in the movable contact of the thermistor-sensitive particulate thermal fuse of the present invention, the spring characteristics can be easily adjusted to a desired range. The overlying or embedded surface need not be formed flat to be flush with the conductive substrate surface, and the surface of the movable contact can be configured to be non-uniform due to the overlying or embedded portion. Therefore, the thickness of the desired area of ​​the movable contact can be varied, allowing the spring force of the movable contact to be adjusted to a desired value. However, the movable contact according to the invention can have any shape and is not limited to this. Figure 2 The recessed star shape illustrated herein is provided that the movable contact retains the elasticity to allow electrical contact with the metal housing, and the mobility to allow smooth sliding without welding or adhesion at predetermined voltage / current ratings.

[0014] like Figure 6 As shown, in the thermistor-type thermal fuse, the first lead 66, cylindrical housing 61, movable contact 67, and second lead 69 are held in a conductive state before operation (a). Then, when abnormal electrical conduction, such as a short circuit in the wiring, causes the temperature at the mounting location to reach the operating temperature of the thermistor-type thermal fuse, the thermistor 62 melts, and the pushing force that pressed and brought the movable contact 67 into contact with the fixed contact 600 at the inner end of the first lead 66 is released, causing the movable contact 67 to separate from the fixed contact 600 of the first lead, and cutting off the electrical conduction between the first lead 66 and the second lead 69, as shown in (b) after operation. The thermistor-type thermal fuse... Figure 6 The operation before (a) is switched to the operation after (b), thereby stopping the power supply and distribution to the electrical equipment and preventing overheating damage or fire accidents in the electrical equipment.

[0015] Beneficial effects of the present invention

[0016] According to embodiments of the present invention, by using a movable contact obtained by applying a contact material made of multilayer materials as the movable contact of a thermistor-type thermal fuse, it is possible to maintain the low internal resistance of the thermistor-type thermal fuse and adjust the spring characteristics while using a less expensive conductive substrate, thereby reducing soldering and adhesion to the leads. Additionally, it is expected to reduce the use of precious metal materials. Attached Figure Description

[0017] Figure 1 This is an illustration showing a portion of the contact material 10 according to the present invention. Figure 1 (a) is an illustration showing an example of a movable contact including the surface of one side of the contact portion with the fixed contact and the stamping position of the movable contact, and Figure 1 (b) is an illustration of an example of a movable contact including one side of the contact portion with the cylindrical housing and the stamped position of the movable contact.

[0018] Figure 2 An example of the shape of the movable contact 20 according to the invention is shown. Figure 2 (a) is a plan view. Figure 2 (b) is a side view. Figure 2 (c) is the bottom view.

[0019] Figure 3 An example of a cross-sectional view of a movable contact according to the present invention is shown. Figure 3 (a) is by going along Figure 2 The view obtained by flattening the cross section of line DD in (a) into a flat plate, and Figure 3 (b) is by going along Figure 2 The view obtained by flattening the cross section of line dd in (a) into a flat plate.

[0020] Figure 4 This is a cross-sectional view showing a thermistor particle-type thermal fuse 40 suitable for application with the movable contact 20 according to the present invention.

[0021] Figure 5 An example of a cross-sectional view of a movable contact according to a variant is shown. Figure 5 (a) is by going along Figure 2 The view obtained by flattening the cross section of line DD in (a) into a flat plate, and Figure 5 (b) is by going along Figure 2 The view obtained by flattening the cross section of line dd in (a) into a flat plate.

[0022] Figure 6 This is a cross-sectional view illustrating the operation of the thermistor particle-type thermal fuse according to the present invention. Figure 6(a) shows a cross-sectional view of the thermistor granular thermal fuse before operation, and Figure 6 (b) shows a cross-sectional view of the thermistor granular thermal fuse after operation.

[0023] Figure 7 This is an illustration showing a variation of the stamping position of the movable contact in the contact material 10 according to the present invention. Figure 7 (a) is a diagram illustrating a variation of a stamped position on the surface of the movable contact, including the portion that contacts the fixed contact, and Figure 7 (b) is a diagram illustrating a variation of a stamped position on the surface of the movable contact, including the portion that contacts the cylindrical housing. Detailed Implementation

[0024] Figure 1 An example of a contact material 10 for a thermal fuse according to the present invention is shown. The contact material 10 for the thermal fuse includes a conductive substrate 11 and a conductive member 12 disposed in a necessary area of ​​the conductive substrate 11. The conductive member 12 is disposed only in the desired portion of the thermistor-type thermal fuse, including the contact portion with the fixed contact and the cylindrical housing, and is made of a material having a Young's modulus and rigidity different from those of the conductive substrate. Figure 1 This is an illustration showing an example of a portion of the contact material before the movable contact is stamped, wherein Figure 1 The star-shaped portion 13 indicates the stamped position of the movable contact. The contact material 10 for the thermal fuse is processed into a predetermined shape and can be applied to... Figure 4 The movable contact 47 of the thermistor particle-type thermal fuse 40 shown. For example, the contact material 10 for the thermal fuse according to the invention is processed by stamping into a shape such as... Figure 2 or Figure 3 The movable contacts 20 or 30 shown are used. The contact material 10 for the thermal fuse includes a conductive substrate 11 having a spring force, being easily compressible, having good compression return capability, and possessing a high Young's modulus and high rigidity, and a conductive member 12 disposed in a necessary area of ​​the conductive substrate 11 and having a lower Young's modulus and rigidity than the conductive substrate 11. The conductive member 12 may be disposed only in the desired portion of the thermistor-sensitive granular thermal fuse, including the contact portion with the fixed contact and the cylindrical housing. Figure 1 The conductive member 12 on side (a) includes a surface that contacts the fixed contact of the thermal fuse, and is Figure 2 The inner surface 22a of the recessed surface of the movable contact 20. On the other hand, it is provided with Figure 1The conductive member 12 on side (b) includes a surface that contacts the cylindrical housing of the thermal fuse, and is Figure 2 The movable contact 20 has a recessed surface 22b. The contact material 10 for the thermal fuse is formed as a movable contact 20 having a star shape, which includes five-point extensions, for example, these extensions are further bent in a bowl or dish shape in one direction, and the fixed contact of the thermal fuse abuts against the bottom surface of the bowl or dish-shaped inner surface 22a of these extensions, such that the outer surface 22b of these extensions contacts and is slidable against the inner wall of the cylindrical housing of the thermal fuse. A conductive member 12 is disposed in an overlying body that extends at least in the contact portion with the fixed contact of the conductive substrate 11 and the contact portion with the cylindrical housing, or disposed in an insert that assembles the conductive member 12 into at least the contact portion with the fixed contact of the conductive substrate 11 and the contact portion with the cylindrical housing. By combining the conductive member with the conductive substrate, the movable contact of the present invention makes it possible to combine materials with different Young's moduli and to change the thickness of the contact material itself as needed. This makes it easy to adjust the spring characteristics of the contact material to the desired range, thereby suppressing the reduction in spring force of the movable contact material caused by annealing. It should be noted that the overlay or embedded surface does not necessarily need to be formed flush with the conductive substrate surface, and can be configured to be uneven due to the overlay or embedded portion. Preferably, the movable contact 20 is provided with... Figure 2 The movable contact 20 is shown as a recessed star shape. The movable contact 20 can have any shape and is not limited to a star shape, as long as it can contact and separate from the fixed contact of the desired thermistor-sensitive particle-type thermal fuse, and contact and slide against the inner wall of the cylindrical housing. For example, a star shape with increased or decreased angles or a disc shape is also possible. Additionally, the movable contact 20 can be modified at the interface between the conductive substrate 51 and the conductive member 52 to have a metal interface layer 53, which is composed of any of Ag plating, Ni plating, Ni-P alloy plating, and Ni-based alloy plating, to prevent interdiffusion of the two materials and improve their adhesion. This delays or prevents the conductive member 12 from diffusing into the conductive substrate 11 in a thermal environment.

[0025] Methods for changing the Young's modulus and rigidity of the contact material 10 include: creating a thickness difference between the conductive substrate 11 and the conductive member 12; changing the degree of work hardening between the materials of the conductive substrate 11 and the conductive member 12 by rolling / forging, etc., or creating a difference by work hardening one of the conductive substrate 11 and the conductive member 12; and creating a difference by changing the degree of heat treatment such as quenching / annealing between the materials of the conductive substrate 11 and the conductive member 12, or by applying any of the above heat treatments to one of the materials of the conductive substrate 11 and the conductive member 12. Furthermore, when the conductive member 12 is made of an alloy, the Young's modulus and rigidity of the contact material 10 can be adjusted by increasing or decreasing the content of the metal components or metal oxides constituting the alloy. For example, in the case of an Ag alloy, the Young's modulus and rigidity of the contact material 10 can be adjusted by increasing or decreasing the content of components such as CuO, Ni, SnO2, In2O3, etc.

[0026] The thermistor-sensitive particle-type thermal fuse 40 according to the present invention is a thermistor-sensitive particle-type thermal fuse utilizing contact material 10 or movable contact 20 for thermal fuses. For example... Figure 4As shown, the thermistor-type thermal fuse 40 includes, inside a cylindrical housing 41 having good electrical and thermal conductivity: a thermistor 42 that melts or softens at a specific temperature; a strong compression spring 43 configured to press the thermistor 42; an insulating cover 44 that closes the opening of the cylindrical housing 41; a weak compression spring 45 abutting against the insulating cover 44; a first lead 46 extending through the insulating cover 44 and including an inner end as a fixed contact 400; a movable contact 47 electrically connected to the first lead 46 and the cylindrical housing 41; a sealing resin 48 configured to surround a portion of the first lead 46, cover the outer end portion of the insulating cover 44, and seal the opening end portion of the cylindrical housing 41; and a second lead 49 disposed at one end of the cylindrical housing 41. The movable contact 47 includes a conductive substrate and a conductive member covering a predetermined surface of the conductive substrate. The conductive member is disposed only in the desired portion, including the contact portion with the fixed contact 400 and the cylindrical housing 41, and is made of a material having a Young's modulus and stiffness different from those of the conductive substrate. The conductive member can be disposed in the contact portion of the conductive substrate with the fixed contact and the cylindrical housing by an overlay extending the conductive member of the movable contact onto a flat surface of the conductive substrate, or by an insert fitting the conductive member into a cavity disposed in the conductive substrate. The movable contact is composed of a conductive substrate and a conductive member, allowing for the combination of materials with different Young's moduli and the variation of the thickness of the contact material itself as needed. Therefore, the movable contact of the thermistor-sensitive particulate thermal fuse of the present invention helps to adjust the spring characteristics to a desired range and suppresses the reduction of the spring force of the movable contact material caused by annealing. The overlay surface or the embedded surface does not necessarily need to be formed flush with the surface of the conductive substrate and can be configured to be non-uniform due to the overlay portion or the embedded portion. For example, although in Figure 4 Not specifically shown, but the movable contact 47 is provided with an upper cover layer or an inlay layer, which is composed of an elastic conductive substrate 21 and conductive members 22a and 22b. The conductive substrate 21 is easily compressible, has good compression recovery capability, and also has a high Young's modulus and high rigidity. Furthermore, the conductive members 22a and 22b have a lower Young's modulus and rigidity than the conductive substrate 21 in the desired portion 22a, including the contact portion with the fixed contact 400, and in the contact portion 22b with the cylindrical housing 41. Figure 2 As shown. The thermally sensitive particle type thermal fuse 40 may also be provided with pressure plates 401 at both ends of the strong compression spring 43 as needed, and the first lead 46 may be inserted into the insulating ceramic tube 402 as needed, and the insulating ceramic tube 402 may be adhered by the sealing resin 48.

[0027] Example

[0028] Figure 1The contact material 10 for a thermal fuse is shown as Embodiment 1 of the present invention. The contact material 10 for the thermal fuse is composed of a conductive substrate 11 made of phosphor bronze selected from Cu or Cu alloy and a conductive member 12 made of Ag or Ag alloy. The conductive substrate has spring force, is easily compressible, has good compression return capability, and also has high Young's modulus and high rigidity (Cu-8Sn-0.2P, Young's modulus: 110 [E / GPa], shear modulus: 43 [G / GPa], resistance: 2.3 [μΩ·cm]). The conductive member has a lower Young's modulus and rigidity than the conductive substrate 11 and a lower resistance value than the conductive substrate 11 in the desired portion of the conductive substrate 11, including the contact portion with the fixed contact and the cylindrical housing (Young's modulus: 82.7 [E / GPa], shear modulus: 30.3 [G / GPa], resistance: 1.47 [μΩ·cm]). The conductive component 12, made of Ag alloy, is selected from Ag alloys including oxide metal alloys (such as AgCuO, AgSnO2, and AgSnO2-In2O3) and Ag alloys (such as AgNi). While not particularly limited, the conductive component 12 may have a lower resistivity than the conductive substrate 11. The contact material 10 for the thermal fuse is formed as... Figure 2 or Figure 3 The movable contact 20 or 30 of the thermistor-sensitive granular thermal fuse is shown and is used in the thermistor-sensitive granular thermal fuse. Methods for adjusting the Young's modulus and rigidity of the contact material 10 for the thermal fuse include: forming a thickness difference between the conductive substrate 11 and the conductive member 12; changing the degree of work hardening between the materials of the conductive substrate 11 and the conductive member 12 by rolling / forging, etc., or forming a difference by work hardening one of the conductive substrate 11 and the conductive member 12; changing the degree of heat treatment such as quenching / annealing between the materials of the conductive substrate 11 and the conductive member 12, or forming a difference by applying any of the above heat treatments to only one of the materials of the conductive substrate 11 and the conductive member 12; and increasing or decreasing the content of CuO, Ni, SnO2, or In2O3 in the Ag alloy constituting the conductive member 12.

[0029] Figure 2 and Figure 3The movable contacts 20 and 30 of Embodiment 2 of the present invention are shown. The movable contacts 20 and 30 are composed of conductive substrates 21 and 31 made of Cu or Cu alloys and conductive members 22a, 22b, and 32 made of Ag or Ag alloys. These conductive substrates have spring force, are easily compressible, have good compression return capability, and high Young's modulus and high rigidity. These conductive members have a lower Young's modulus and rigidity than the conductive substrates 21 and 31 in desired portions of the conductive substrates 21 and 31, including the contact portions with the fixed contacts and the cylindrical housing. While not particularly limited in this respect, the conductive members 22a, 22b, and 32 may have a lower resistance value than the conductive substrates 21 and 31.

[0030] Figure 2 and Figure 5 The movable contacts 20 and 50 of Embodiment 3 of the present invention are shown. The movable contacts 20 and 50 are composed of conductive substrates 21 and 51 made of phosphor bronze selected from Cu or Cu alloys, and conductive members 22a, 22b, and 52 made of silver selected from Ag or Ag alloys. These conductive substrates have spring force, are easily compressible, have good compression return capability, and also have high Young's modulus and high rigidity (Cu-8Sn-0.2P, Young's modulus: 110 [E / GPa], shear modulus: 43 [G / GPa], resistance... These conductive components have a lower Young's modulus and stiffness than the conductive substrates 21 and 51, and a lower resistance value than the conductive substrates 21 and 51 (Young's modulus: 82.7 [E / GPa], shear modulus: 30.3 [G / GPa], resistance: 1.47 [μΩ·cm]), in the desired portions of the conductive substrates 21 and 51, including the contact portions with the fixed contacts and the cylindrical housing. Furthermore, as... Figure 5 As shown, a metal interface layer 53, composed of a Ni-plated layer, is provided at the interface between the conductive substrate 51 and the conductive member 52 to prevent interdiffusion of the two materials and improve their adhesion. The movable contacts 20 and 50 are composed of conductive substrates and conductive members with different Young's moduli and rigidities. Although there are no particular restrictions on this, the conductive member may have a lower resistance value than the conductive substrate.

[0031] Figure 4A thermistor-sensitive granular thermal fuse 40 is shown as embodiment 4 of the present invention. The thermistor-sensitive granular thermal fuse 40 includes, inside a cylindrical housing 41 having good electrical and thermal conductivity: a thermistor-sensitive granule 42 that melts or softens at a specific temperature; a strong compression spring 43 configured to press the thermistor-sensitive granule 42; an insulating cover 44 that closes the opening of the cylindrical housing 41; a weak compression spring 45 abutting against the insulating cover 44; a first lead 46 extending through the insulating cover 44 and including an inner end as a fixed contact 400; a movable contact 47 electrically connected to the first lead 46 and the cylindrical housing 41; a sealing resin 48 configured to surround a portion of the first lead 46, cover the outer end portion of the insulating cover 44, and seal the open end portion of the cylindrical housing 41; and a second lead 49 disposed at one end of the cylindrical housing 41. The movable contact 47 is composed of a conductive substrate made of phosphor bronze selected from Cu or Cu alloys and a conductive component selected from Ag or Ag alloys. The conductive substrate has spring force, is easily compressible, has good compression return capability, and also has high Young's modulus and high rigidity (Cu-8Sn-0.2P, Young's modulus: 110 [E / GPa], shear modulus: 43 [G / GPa], resistance: 2.3 [μΩ·cm]). The conductive component has a lower Young's modulus and rigidity than the conductive substrate, and a lower resistance value than the conductive substrate. It only covers the area near the contact portion of the conductive substrate with the fixed contact 400 and the cylindrical housing 41 (Young's modulus: 82.7 [E / GPa], shear modulus: 30.3 [G / GPa], resistance: 1.47 [μΩ·cm]). The conductive component made of Ag alloy is selected from Ag alloys including oxide metal alloys (such as AgCuO, AgSnO2, and AgSnO2-In2O3) and Ag alloys (such as AgNi). The movable contact 47 is composed of a conductive substrate and a conductive component having different Young's moduli and rigidities, and while there are no particular limitations, the conductive component may have a lower resistance value than the conductive substrate. Methods for adjusting the Young's modulus and rigidity of the movable contact 47 include: creating a thickness difference between the conductive substrate and the conductive component; changing the degree of work hardening between the materials of the conductive substrate and the conductive component by rolling / forging, or creating a difference by work hardening one of the conductive substrate and the conductive component; changing the degree of heat treatment such as quenching / annealing between the materials of the conductive substrate and the conductive component, or creating a difference by applying any of the above heat treatments to only one of the materials of the conductive substrate and the conductive component; and increasing or decreasing the content of CuO, Ni, SnO2, and In2O3 in the Ag alloy constituting the conductive component.

[0032] Figure 7This is an illustration showing a variation of the stamping position of the movable contact in the contact material 10 according to the present invention. Figure 7 (a) is a diagram illustrating a variation of a stamped position on the surface of these movable contacts, including the portion that contacts the fixed contact, and Figure 7 (b) is a diagram illustrating a variation of the stamped position on the surface of these movable contacts, including the contact portion with the cylindrical housing. Thus, only the stamped position 13 of the movable contact in the contact material 10 needs to be provided and formed, such that the conductive member 12 of the movable contact at least corresponds to the contact portion with the fixed contact and the cylindrical housing of the thermistor-type thermal fuse, and therefore contacts the fixed contact and the cylindrical housing.

[0033] Industrial applicability

[0034] The present invention can be suitably used in temperature protection elements including contacts, such as high-current contact-separating thermal fuses or bimetallic protection elements that include movable contacts and are configured to separate the contacts when an abnormal temperature is detected, and can be particularly suitably used in thermistor particle type thermal fuses.

[0035] List of reference numerals

[0036] 10. Contact materials for thermal fuses

[0037] 11 Conductive substrate

[0038] 12 conductive components

[0039] 13. Stamping position of movable contact

[0040] 20 movable contacts

[0041] 21 conductive substrate

[0042] 22a, 22b conductive components

[0043] 30 movable contacts

[0044] 31 conductive substrate

[0045] 32 conductive components

[0046] 40 Thermosensitive Particle Type Thermal Fuse

[0047] 41 Cylindrical shell

[0048] 42 thermal particles

[0049] 43 strong compression spring

[0050] 44 Insulating Cover

[0051] 45 weak compression spring

[0052] 46 First Lead

[0053] 47 movable contacts

[0054] 48 sealing resin

[0055] 49 Second lead

[0056] 400 fixed contact

[0057] 401 pressure plate

[0058] 402 Insulating Porcelain Tube

[0059] 50 movable contacts

[0060] 51 conductive substrate

[0061] 52 conductive components

[0062] 53 Metal Interface Layer

[0063] 60 Thermosensitive Particle Type Thermal Fuse

[0064] 61 Cylindrical shell

[0065] 62 thermal particles

[0066] 63 strong compression spring

[0067] 64 Insulating Cover

[0068] 65 weak compression spring

[0069] 600 fixed contact

[0070] 66 First Lead

[0071] 67 movable contacts

[0072] 68 sealing resin

[0073] 69 Second lead

[0074] 601 pressure plate

[0075] 602 insulating porcelain tube.

Claims

1. A contact material for a thermal fuse, the contact material comprising: A conductive substrate having a first surface and a second surface; and A conductive member, wherein the conductive member is configured to cover a predetermined area of ​​the surface of the conductive substrate, wherein The conductive member is disposed only on a desired portion of the conductive substrate, including at least a contact portion with the fixed contact of the thermal fuse and a cylindrical housing, wherein the contact portion with the fixed contact is located on the first surface and the contact portion with the cylindrical housing is located on the second surface. Wherein, on at least one of the first and second surfaces, the region on the same surface outside the desired portion lacks the conductive member, such that the portion of the contact material with the conductive member and the portion outside the desired portion have different spring characteristics, and wherein the conductive member is made of a material having a Young's modulus and stiffness different from those of the conductive substrate, wherein the conductive member is disposed on the contact portion by a cover or an insert, the cover being an upper cover that extends the conductive member on the surface of the conductive substrate, the insert being an insert that assembles the conductive member into a cavity disposed in the conductive substrate, and after the conductive member is disposed on the contact portion, the surface of the contact material becomes uneven due to the cover or the insert. The difference in Young's modulus and rigidity between the conductive substrate and the conductive member is configured to suppress the reduction of the spring force of the conductive substrate when the contact material is subjected to a heated environment.

2. The contact material for a thermal fuse according to claim 1, wherein the conductive substrate is Cu or a Cu alloy.

3. The contact material for a thermal fuse according to claim 1, wherein the conductive component is Ag or an Ag alloy.

4. The contact material for a thermal fuse according to claim 3, wherein the Ag alloy is selected from any one of AgCuO, AgSnO2, AgSnO2-In2O3 or AgNi.

5. The contact material for a thermal fuse according to claim 1, wherein a metal interface layer composed of any one of an Ag plating layer, a Ni plating layer, a Ni-P alloy plating layer, and an alloy plating layer with Ni as the main component is disposed at the interface between the conductive substrate and the conductive member.

6. The contact material for a thermal fuse according to claim 1, wherein the conductive substrate is made of a material having a greater spring force than the conductive member, being easier to compress, having better compression return capability, and having a higher Young's modulus and higher rigidity.

7. The contact material for a thermal fuse according to claim 1, wherein the conductive member is made of a material having a lower Young's modulus and lower rigidity than the conductive substrate.

8. The contact material for a thermal fuse according to claim 7, wherein the conductive member is made of a material having a lower resistance than the conductive substrate.

9. A movable contact, the movable contact comprising: A conductive substrate having a first surface and a second surface; and A conductive member, wherein the conductive member is configured to cover a predetermined area of ​​the surface of the conductive substrate, wherein The conductive member is disposed only on a desired portion of the conductive substrate, including at least a contact portion with the fixed contact of the thermal fuse and a cylindrical housing, with the contact portion with the fixed contact located on the first surface and the contact portion with the cylindrical housing located on the second surface. Wherein, on at least one of the first and second surfaces, the region on the same surface outside the desired portion does not contain the conductive member, such that the portion of the movable contact with the conductive member and the portion outside the desired portion have different spring characteristics, and wherein the conductive member is made of a material having a Young's modulus and stiffness different from those of the conductive substrate, wherein the conductive member is disposed on the contact portion by a cover or an insert, the cover being an upper cover that extends the conductive member on the surface of the conductive substrate, the insert being an insert that assembles the conductive member into a cavity disposed in the conductive substrate, and after the conductive member is disposed on the contact portion, the surface of the movable contact is uneven due to the cover or the insert, and The difference in Young's modulus and rigidity between the conductive substrate and the conductive member is configured to suppress the reduction of the spring force of the conductive substrate when the movable contact is subjected to a heated environment.

10. The movable contact according to claim 9, wherein the conductive substrate is Cu or a Cu alloy.

11. The movable contact according to claim 9, wherein the conductive member is Ag or an Ag alloy.

12. The movable contact according to claim 11, wherein the Ag alloy is selected from any one of AgCuO, AgSnO2, AgSnO2-In2O3 or AgNi.

13. The movable contact according to claim 9, wherein a metal interface layer composed of any one of an Ag plating layer, a Ni plating layer, a Ni-P alloy plating layer, and an alloy plating layer with Ni as the main component is disposed at the interface between the conductive substrate and the conductive member.

14. The movable contact according to claim 9, wherein the conductive substrate is made of a material having a greater spring force than the conductive member, being easier to compress, having better compression return capability, and having a higher Young's modulus and higher rigidity.

15. The movable contact according to claim 9, wherein the conductive member is made of a material having a lower Young's modulus and lower rigidity than the conductive substrate.

16. The movable contact of claim 15, wherein the conductive member is made of a material having a lower resistance than the conductive substrate.

17. A thermistor-sensitive granular thermal fuse, The interior of the cylindrical shell, which has good electrical and thermal conductivity, includes: Thermosensitive particles, which melt or soften at a specific temperature; A high-compression spring, the high-compression spring being configured to press the heat-sensitive particles; An insulating cover that closes the opening of the cylindrical housing; A weak compression spring abuts against the insulating cover; A first lead extends through the insulating cover and includes an inner end that serves as a fixed contact; A movable contact, which is electrically connected to the first lead and the cylindrical housing; A sealing resin is provided to surround a portion of the first lead, cover the outer end portion of the insulating cap, and seal the open end portion of the cylindrical housing. and The second lead is disposed at one end of the cylindrical housing, wherein... The movable contact includes a conductive substrate and a conductive member covering a predetermined surface of the conductive substrate. The conductive substrate has a first surface and a second surface. The conductive member is disposed only on a desired portion of the conductive substrate, including a portion that contacts at least the inner wall surface of the fixed contact and the cylindrical housing. The portion that contacts the fixed contact is located on the first surface, and the portion that contacts the cylindrical housing is located on the second surface. Wherein, on at least one of the first and second surfaces, the region on the same surface outside the desired portion lacks the conductive member, such that the portion of the contact material with the conductive member and the portion outside the desired portion have different spring characteristics, and wherein the conductive member is made of a material having a Young's modulus and stiffness different from those of the conductive substrate, wherein the conductive member is disposed on the contact portion by a cover or an insert, the cover being an upper cover that extends the conductive member on the surface of the conductive substrate, the insert being an insert that assembles the conductive member into a cavity disposed in the conductive substrate, and after the conductive member is disposed on the contact portion, the surface of the contact material becomes uneven due to the cover or the insert. The difference in Young's modulus and rigidity between the conductive substrate and the conductive member is configured to suppress the reduction of the spring force of the conductive substrate when the contact material is subjected to a heated environment.

18. The thermistor granular thermal fuse according to claim 17, wherein the conductive substrate is Cu or a Cu alloy.

19. The thermistor granular thermal fuse according to claim 17, wherein the conductive component is Ag or an Ag alloy.

20. The thermistor granular thermal fuse according to claim 19, wherein the Ag alloy is selected from any one of AgCuO, AgSnO2, AgSnO2-In2O3 or AgNi.

21. The thermistor particle-type thermal fuse according to claim 17, wherein a metal interface layer composed of any one of an Ag plating layer, a Ni plating layer, a Ni-P alloy plating layer, and an alloy plating layer with Ni as the main component is disposed at the interface between the conductive substrate and the conductive member.

22. The thermistor granular thermal fuse of claim 17, wherein the conductive substrate is made of a material having a greater spring force than the conductive member, being easier to compress, having better compression recovery capability, and having a higher Young's modulus and higher rigidity.

23. The thermistor granular thermal fuse of claim 17, wherein the conductive member is made of a material having a lower Young's modulus and lower rigidity than the conductive substrate.

24. The thermistor particle-type thermal fuse of claim 23, wherein the conductive member is made of a material having a lower resistance than the conductive substrate.

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