EP0526050A2 - Fusible - Google Patents

Fusible Download PDF

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Publication number
EP0526050A2
EP0526050A2 EP92306533A EP92306533A EP0526050A2 EP 0526050 A2 EP0526050 A2 EP 0526050A2 EP 92306533 A EP92306533 A EP 92306533A EP 92306533 A EP92306533 A EP 92306533A EP 0526050 A2 EP0526050 A2 EP 0526050A2
Authority
EP
European Patent Office
Prior art keywords
envelope
fuse
wire
terminals
breaking
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP92306533A
Other languages
German (de)
English (en)
Other versions
EP0526050A3 (en
Inventor
Toshiyuki c/o DAITO COMMUN. APPAR.CO. LTD Hanada
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Daito Communication Apparatus Co Ltd
Daito Tsushinki KK
Original Assignee
Daito Communication Apparatus Co Ltd
Daito Tsushinki KK
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Daito Communication Apparatus Co Ltd, Daito Tsushinki KK filed Critical Daito Communication Apparatus Co Ltd
Publication of EP0526050A2 publication Critical patent/EP0526050A2/fr
Publication of EP0526050A3 publication Critical patent/EP0526050A3/en
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
    • H01H85/02—Details
    • H01H85/04—Fuses, i.e. expendable parts of the protective device, e.g. cartridges
    • H01H85/05—Component parts thereof
    • H01H85/18—Casing fillings, e.g. powder
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
    • H01H85/0078—Security-related arrangements
    • H01H85/0082—Security-related arrangements preventing explosion of the cartridge
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H85/00—Protective devices in which the current flows through a part of fusible material and this current is interrupted by displacement of the fusible material when this current becomes excessive
    • H01H85/02—Details
    • H01H85/04—Fuses, i.e. expendable parts of the protective device, e.g. cartridges
    • H01H85/041—Fuses, i.e. expendable parts of the protective device, e.g. cartridges characterised by the type
    • H01H85/044—General constructions or structure of low voltage fuses, i.e. below 1000 V, or of fuses where the applicable voltage is not specified
    • H01H85/045—General constructions or structure of low voltage fuses, i.e. below 1000 V, or of fuses where the applicable voltage is not specified cartridge type
    • H01H85/0456—General constructions or structure of low voltage fuses, i.e. below 1000 V, or of fuses where the applicable voltage is not specified cartridge type with knife-blade end contacts

Definitions

  • This invention relates to a fuse used to protect electronic parts and equipment from an overcurrent.
  • a fuse generally performs its function of protecting circuit components from the overcurrent by breaking the circuit when a fuse element, generally metal, is heated by joule heat to its melting point.
  • the metal When the fuse element melts, the metal vaporizes, causing the pressure within an envelope containing the fuse element, generally a wire, to increase. This increase of internal pressure can substantially damage the fuse.
  • the protecting role of a fuse is completed when the smallest part at the center of the fusible wire, the part where heat dissipation is most difficult, melts.
  • the current that flows into the metal wire is large.
  • the entire wire melts, often vaporizing instantly.
  • some conventional fuses provide extra space within the envelope containing the fuse element and position terminals connected to the fuse element outside the envelope.
  • the dimensions of the extra space are chosen in relation to the amount of metal in the fuse element.
  • fuses are known that cover the fusible metal wires with flexible synthetic resin, thereby substituting the resin for the extra space.
  • Such a fuse is disclosed, for example, in japanese Utility Model Publication No. 38988/1983.
  • covering fusible metal wires with flexible synthetic resin presents a problem. Such a configuration cannot ensure sufficient circuit-breaking function while simultaneously resisting the mechanical load from the envelope containing the fuse element.
  • the present invention has been devised to solve this problem.
  • An object of the present invention is to provide a compact fuse capable of reliably dissipating thermal energy generated by an overcurrent.
  • An further object of the present invention is to provide a compact fuse that overcomes the drawbacks of the prior art.
  • Still a further object of the present invention is to provide a compact fuse capable of reliably dissipating thermal energy generated by an overcurrent before it damages the envelope containing the fuse element.
  • Still a further object of the present invention is to provide a compact fuse that utilizes the space in the envelope containing the fuse element more effectively than the prior art, thereby improving the circuit-breaking function of the fuse.
  • the present invention provides an improved compact fuse that has a fusible metal wire extending between a pair of metal terminals.
  • the wire and the portion of the terminals to which the wire is connected are enclosed in an envelope made of insulation material.
  • the ends of the terminals protrude outside the envelope.
  • Filling the envelope with cellular resin covers the wire and creates many isolated spaces that dissipate the thermal energy generated when the wire melts from overcurrent, thereby preventing damage to the envelope.
  • a fuse comprises: means for breaking an electric circuit in response to an overcurrent; envelope means enclosing the means for breaking and defining a substantially closed space therebetween; and a cellular resin substantially filling the substantially closed space.
  • a fuse comprises: a metal wire effective for breaking an electric circuit in response to an overcurrent; a pair of metal terminals; the metal wire extending between the pair of metal terminals; an envelope made of insulation material; and the envelope forming a substantially enclosed space between itself and a cellular resin covering the metal wire and substantially filling the substantially closed space.
  • a fuse comprises: means for breaking an electric circuit in response to an overcurrent; first envelope means enclosing the means for breaking and defining a first substantially closed space therebetween; and second envelope means enclosing the first envelope means and defining a second substantially closed space therebetween.
  • a fuse comprises: a metal wire; the metal wire being fusible at a high current therethrough for breaking an electric circuit; an envelope enclosing the metal wire; the envelope defining a substantially closed space between itself and the metal wire; and means for dividing the substantially closed space into a plurality of substantially closed spaces, whereby products generated by fusing the metal wire remain inside the envelope.
  • the fuse of the present invention has a second space formed inside the envelope containing the fuse element.
  • the second space is made by enclosing the fusible metal wire contained in the envelope with a box-shaped enclosure frame. Even if the enclosure frame is cracked or broken by the increase of pressure that results from fusion of the fuse element, thermal energy, which may otherwise damage the envelope, is consumed, thereby reducing the applied load.
  • Fig. 1 illustrates how a fuse works according to a first embodiment of the present invention.
  • Fig. 2(a) is an exploded front view of a fuse according to the embodiment of the present invention shown in Fig. 1.
  • Fig. 2(b) is an exploded side view of a fuse according to the embodiment of the present invention shown in Fig. 1.
  • Fig. 3 is a vertical sectional view without a lid of a fuse according to the embodiment of the present invention shown in Fig. 1.
  • Fig. 4 is a vertical sectional view of with a lid of a fuse according to the embodiment of the present invention shown in Fig. 1.
  • Fig. 5 is a vertical sectional view of a conventional fuse.
  • Fig. 6 is a vertical sectional view of another conventional fuse.
  • Fig. 7 illustrates how a conventional fuse works.
  • Fig. 8 illustrates a fuse according to a second embodiment of the present invention
  • a fuse 14 has a fusible metal wire 12 extending between a pair of metal terminals 11, 11. Wire 12 and portions of metal terminals 11, 11 are contained in an envelope 13. The ends of terminals 11, 11 protrude from envelope 13. Cellular resin 15 covers wire 12 and the portions of terminals 11, 11 inside envelope 13. When an overcurrent passes through a circuit of which fuse 14 is an element, wire 12 is heated to melting, thereby breaking the circuit.
  • a fusible metal wire 20 extends between a pair of metal terminals 21, 21.
  • Wire 20 and portions of metal terminals 21, 21 are contained in an envelope 22 made of insulating material, such as, for example, polyether sulfone.
  • the ends of terminals 21, 21 protrude from opening 23 of envelope 22.
  • Cellular resin 24, such as, for example, KE521 (A ⁇ B) manufactured by Shinetsu Chemical Co., Ltd., is poured from opening 23 into envelope 22 to cover wire 20 and the portions of terminals 21, 21 inside envelope 22.
  • lid 25 which may be formed from polyethylene terephthalate.
  • Sample A had the configuration of the embodiment of the present invention shown in Fig. 4, whose description is the same as that in Figs. 2 and 3 and is therefore omitted here.
  • Sample B had the conventional configuration shown in Fig. 5.
  • a fusible metal wire 32 connected to metal terminals 31 at both ends is contained in an envelope 30.
  • a space 33 is provided around wire 32.
  • Sample C had the conventional configuration shown in Fig. 6.
  • a fusible metal wire 37 connected to metal terminals 36 at both ends is contained in envelope 31.
  • Wire 37 is covered with a flexible resin 38 (Silicone Varnish KR-2038 manufactured by Shinetsu Chemical Co., Ltd.).
  • a circuit-breaker test was conducted by running 50 Amperes of current at 130 V DC for 1.3 mm/second through five examples each of Samples A, B, and C. The results of the test are shown in Table 1 below.
  • the present embodiment has a configuration in which a fusible metal wire is covered by a cellular resin
  • a combination of a cellular resin and a flexible resin may be used instead. Improving the circuit-breaking function of a fuse without damaging its envelope is also possible by means of a cellular resin in which a filler, such as an arc-extinguishing agent, is dispersed.
  • the method of the present invention is not limited to the above embodiment where a cellular resin is poured into a box-shaped envelope.
  • Fusible metal wires may be covered with cellular resin by casting, or envelopes may be produced by casting or by transfer molding under low pressure.
  • the present invention makes it possible to improve the circuit-breaking function of fuses with a simple structure, while preventing cracks or breakages of envelopes when the pressure inside the envelopes increases as a result of melting or vaporization of the metal wires.
  • some conventional fuses provide an envelope 2 with a space 3 therein, the dimension of space 3 being determined with respect to the amount of metal used in a metal wire 1 that serves as the fuse element.
  • a pair of terminals 4, 4 connected to both ends of wire 1 are placed with as much of their body as possible out of envelope 2.
  • a second space 6 is formed inside envelope 2 by enclosing wire 1 within envelope 2 in a box-shaped enclosure frame 5. Even if frame 5 is cracked or broken by the increase of pressure in second space 6 when wire 1 fuses, enough thermal energy that might otherwise damage envelope 2 is dissipated to reduce the load applied to envelope 2 below the damage point.

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  • Fuses (AREA)
EP19920306533 1991-07-29 1992-07-16 Fuse Ceased EP0526050A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP188796/91 1991-07-29
JP3188796A JPH0536344A (ja) 1991-07-29 1991-07-29 ヒユーズ

Publications (2)

Publication Number Publication Date
EP0526050A2 true EP0526050A2 (fr) 1993-02-03
EP0526050A3 EP0526050A3 (en) 1993-08-25

Family

ID=16229954

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19920306533 Ceased EP0526050A3 (en) 1991-07-29 1992-07-16 Fuse

Country Status (2)

Country Link
EP (1) EP0526050A3 (fr)
JP (1) JPH0536344A (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2725304A1 (fr) * 1994-10-03 1996-04-05 Soc Corp Fusible pour microplaquette

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1203861A (en) * 1968-05-23 1970-09-03 Reyrolle A & Co Ltd Improvements relating to low-voltage electric fuses
WO1987000964A1 (fr) * 1985-08-05 1987-02-12 Dubilier Plc Elements de remplacement electriques
US4709222A (en) * 1984-08-06 1987-11-24 Kabushiki Kaisha S.K.K. Fuse device
EP0300654A2 (fr) * 1987-07-24 1989-01-25 THE GENERAL ELECTRIC COMPANY, p.l.c. Fusibles de protection électrique

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1203861A (en) * 1968-05-23 1970-09-03 Reyrolle A & Co Ltd Improvements relating to low-voltage electric fuses
US4709222A (en) * 1984-08-06 1987-11-24 Kabushiki Kaisha S.K.K. Fuse device
WO1987000964A1 (fr) * 1985-08-05 1987-02-12 Dubilier Plc Elements de remplacement electriques
EP0300654A2 (fr) * 1987-07-24 1989-01-25 THE GENERAL ELECTRIC COMPANY, p.l.c. Fusibles de protection électrique

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2725304A1 (fr) * 1994-10-03 1996-04-05 Soc Corp Fusible pour microplaquette
NL1000560C2 (nl) * 1994-10-03 1997-07-30 Soc Corp Microchipsmeltveiligheid.

Also Published As

Publication number Publication date
EP0526050A3 (en) 1993-08-25
JPH0536344A (ja) 1993-02-12

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