EP0584800B1 - Positive temperature coefficient thermistor device - Google Patents

Positive temperature coefficient thermistor device Download PDF

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Publication number
EP0584800B1
EP0584800B1 EP19930113532 EP93113532A EP0584800B1 EP 0584800 B1 EP0584800 B1 EP 0584800B1 EP 19930113532 EP19930113532 EP 19930113532 EP 93113532 A EP93113532 A EP 93113532A EP 0584800 B1 EP0584800 B1 EP 0584800B1
Authority
EP
European Patent Office
Prior art keywords
case
temperature coefficient
positive temperature
terminal
coefficient thermistor
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.)
Expired - Lifetime
Application number
EP19930113532
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0584800A3 (en
EP0584800A2 (en
Inventor
Asami Wakabayashi
Norihiro Mochida
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.)
Murata Manufacturing Co Ltd
Original Assignee
Murata Manufacturing Co Ltd
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 Murata Manufacturing Co Ltd filed Critical Murata Manufacturing Co Ltd
Publication of EP0584800A2 publication Critical patent/EP0584800A2/en
Publication of EP0584800A3 publication Critical patent/EP0584800A3/en
Application granted granted Critical
Publication of EP0584800B1 publication Critical patent/EP0584800B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/10—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/12—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
    • H05B3/14—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material the material being non-metallic
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C1/00—Details
    • H01C1/01—Mounting; Supporting
    • H01C1/014—Mounting; Supporting the resistor being suspended between and being supported by two supporting sections
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C1/00—Details
    • H01C1/14—Terminals or tapping points or electrodes specially adapted for resistors; Arrangements of terminals or tapping points or electrodes on resistors
    • H01C1/1406—Terminals or electrodes formed on resistive elements having positive temperature coefficient

Definitions

  • the present invention relates generally to a positive temperature coefficient thermistor device constructed by containing a plurality of positive temperature coefficient thermistor elements, and more particularly, to a positive temperature coefficient thermistor device used for, for example, a heating device in an electronic mosquito catcher.
  • Fig. 5 shows a conventionally known positive temperature coefficient thermistor device used for, for example, a heating device in an electronic mosquito catcher.
  • This positive temperature coefficient thermistor device 50 comprises two positive temperature coefficient thermistor (hereinafter referred to as PTC) elements 51 and 51, a plane terminal 52, a spring terminal 53, and an insulator case 54.
  • PTC positive temperature coefficient thermistor
  • Each of the plane terminal 52 and the spring terminal 53 has a pair of branched ends.
  • the pair of branched ends of the plane terminal 52 and the pair of branched ends of the spring terminal 53 are disposed opposed to each other, and the PTC elements 51 and 51 are interposed therebetween.
  • Containing recess portions 55 and 55 are formed in the insulator case 54, and the branched ends of the plane terminal 52, the PTC element 51, and the branched ends of the spring terminal 53 are contained in this order in each of the containing recess portions 55 and 55.
  • a surface of the insulator case 54 to which the containing recess portions 55 and 55 open is closed by a cover plate 56 composed of an insulator.
  • a heat radiating plate 57 abuts on the bottom surface of the insulator case 54.
  • a mounting piece 58 provided for the heat radiating plate 57 is folded along the outer surface of the insulator case 54 and the above described cover plate 56, so that the heat radiating plate 57 is mounted on the insulator case 54, and the cover plate 56 is fixed to the case 54 so as to close the surface of the case 54 to which the containing recess portion 55 opens.
  • the PTC elements 51 generate heat.
  • the heat generated is transferred to the insulator case 54 through the plate terminal 52 which is brought into surface contact with the bottom wall of the containing recess portion 55.
  • this heat is conducted to the heat radiating plate 57 mounted on the insulator case 54, thereby to make it possible to take out the heat to the exterior from the heat radiating plate 57. That is, the heat radiating plate 57 is used as a heating portion for heating, for example, a mat impregnated with a drug in an electronic mosquito catcher.
  • thermal efficiency in the case of heating is not sufficient, and the surface temperature of the heat radiating plate 57 functioning as a heating surface varies.
  • the reason for this is considered as follows.
  • the size of the plate terminal 52 depends on the size of the containing recess portions 55 and 55.
  • thermal conductivity in the insulator case 54 must be increased by making the size of a space in the containing recess portions 55 and 55 as small as possible. Consequently, the size of the containing recess portions 55 and 55 and particularly, the area of their opening is made approximately the same as the area of a major surface of the PTC element 51. Therefore, it is impossible to significantly increase the size of the plane terminal 52, as compared with the PTC element 51, and it is impossible to enhance the heat radiating properties of the heat generated in the PTC element 51. Consequently, it is considered that the above described thermal efficiency is decreased.
  • the insulator case 54 is generally composed of ceramics such as alumina.
  • the insulator case 54 has the containing recess portion 55 and the like, so that the structure of the insulator case 54 is relatively complicated. Consequently, it is difficult to increase the forming precision of the insulator case 54. Accordingly, the bottom surface of the containing recess portion 55 receiving heat by the surface contact with the plane terminal 52 is not always easily formed into a smooth surface.
  • the plane surface 52 does not easily adhere to the bottom surface of the containing recess portion 55, which causes the heat radiating properties of the heat generated in the PTC elements 51 to be degraded, or causes the surface temperature of the heating surface, that is, the heat radiating plate 57 in the positive temperature coefficient thermistor device 50 to vary.
  • a known positive temperature coefficient thermistor device (GB 21 81 629 A) comprises a case with a containing recess. An elastic terminal, a PTC element and a plane terminal are contained in the containing recess in this order. A cover member is mounted on the case to close the upper surface of the case and to be in contact with the plane terminal.Thus, the cover member functions as heating portion for heating an object to be heated.
  • the object of the present invention is to provide a positive temperature coefficient thermistor device which is superior in thermal efficiency and is uniform in surface temperature of heating surface.
  • Claim 8 is directed to the use of a PTC device according to claim 1 as a heating device in an electronic mosquito catcher.
  • the plane terminal is disposed between the upper surface of the case and the cover member on the side of the surface of the case to which the containing recess portion opens, thereby to make it possible to set the size of the plane terminal without depending on the size of the containing recess portion. Consequently, the size of the plane terminal can be made as large as possible in the range of a predetermined withstand voltage, thereby to make it possible to take out heat generated in the PTC elements to the exterior more efficiently by the increase in size.
  • the cover member is only mounted so as to close the surface of the case to which the containing recess portion opens, so that the structure thereof is relatively simple. Consequently, it is possible to easily smooth the surface of not only the plane terminal but also the cover member. Accordingly, the plane terminal which is brought into elastic contact with the cover member by an urging force of the elastic terminal and the cover member are sufficiently brought into surface contact with each other. Consequently, heat efficiency is increased by the area of contact, so that the variation in the temperature of the heating surface in the positive temperature coefficient thermistor device is decreased.
  • the plane terminal comprises a plurality of plane terminal portions and a connecting piece for connecting the plurality of plane terminal portions, so that the respective plane terminal portions can be moved relatively freely. Accordingly, the plane terminal portions can sufficiently follow the urging force of the elastic terminal and the shape of the cover member. Also from this point, the plane terminal portions sufficiently adhere to the cover member, thereby to increase heat efficiency.
  • the above described plane terminal further comprises an overcurrent fusing portion, and the overcurrent fusing portion is bent in the direction away from the inner wall of the containing recess portion in the case.
  • the overcurrent fusing portion is fused, thereby to make it possible to stop energization.
  • the overcurrent fusing portion is bent in the direction away from the inner wall of the containing recess portion, thereby to make it possible to prevent heat generated in the overcurrent fusing portion from being conducted to the case. Consequently, it is also possible to solve the problem that an overcurrent fusing time period is extended due to radiation of heat to the case.
  • Fig. 1 is an exploded perspective view for explaining a positive temperature coefficient thermistor device according to one embodiment of the present invention
  • Fig. 2 is a cross sectional view showing the positive temperature coefficient thermistor device.
  • a positive temperature coefficient thermistor device 1 is used as a heating device for heating a mat impregnated with a drag in an electronic mosquito catcher, although the positive temperature coefficient thermistor device according to the present embodiment can be used as a heating device for heating a substance to be heated in various applications other than the heating device in the electronic mosquito catcher.
  • the positive temperature coefficient thermistor device 1 comprises a case 2 composed of an insulator, two PTC elements 3, a spring terminal 4 serving as an elastic terminal, a plane terminal 5, a cover plate 6, and a heat radiating plate 7.
  • the case 2 is composed of insulating ceramics such as alumina in the present embodiment.
  • the case 2 may be composed of the other insulating material which can resist heat generation of the PTC elements 3.
  • Containing recess portions 8 are formed in the case 2.
  • the spring terminal 4 has a pair of branched ends, and each of the branched ends is bent to form a spring terminal portion 4a.
  • the spring terminal 4 and the PTC element 3 are contained in this order in each of the containing recess portions 8 and 8 in the case 2.
  • the spring terminal 4 is contained in each of the containing recess portions 8 and further, the PTC element 3 is mounted on the spring terminal portion 4a of the spring terminal 4.
  • each of the PTC elements 3 is lifted from the bottom surface of the containing recess portion 8 by the spring terminal portion 4a, so that the upper surface of the PTC element 3 is projected slightly upward from an upper end of the containing recess portion 8.
  • the plane terminal 5 is used both as a terminal for applying a voltage and a heat conducting plate.
  • This plane terminal 5 is constructed by machining a metal plate, and has plane terminal portions 5a in a flat plate shape and an overcurrent fusing portion 10.
  • the number of plane terminal portions 5a is two, which corresponds to the number of PTC elements 3.
  • the plane terminal portions 5a are disposed side by side, and is connected to each other by a pair of narrow connecting pieces 5b.
  • the above described overcurrent fusing portion 10 comprises a narrow portion for fusing 10a which connects with the plane terminal portion 5a and a lead-out terminal 10b provided so as to connect with the narrow portion 10a, as shown in Fig. 4.
  • the overcurrent fusing portion 10 is extended forward in a direction substantially orthogonal to a terminal surface of the plate terminal portion 5a, only the above described narrow portion 10a is bent in a direction inclined from the direction orthogonal to the terminal surface of the plane terminal portion 5a.
  • the plane terminal 5 thus constructed is mounted on an upper surface 2a which is a surface of the case 2 to which the containing recess portions 8 open so as to cover the containing recess portions 8.
  • the plane terminal 5 is mounted on the upper surface 2a of the case 2, so that the PTC elements 3 slightly projected from the containing recess portions 8 are interposed between the plane terminal 5 and the spring terminal 4.
  • the overcurrent fusing portion 10 is contained in a containing portion 11 provided for the case 2 for containing the overcurrent fusing portion 10.
  • the lead-out terminal 10b of the overcurrent fusing portion 10 passes through the above described containing portion 11, and is pulled outward from the reverse surface of the case 2.
  • the direction in which the above described narrow portion 10a is bent is set to the direction away from the inner wall of the containing portion 11, to prevent the narrow portion 10a from being brought into contact with the inner wall of the containing portion 11.
  • the cover plate 6 is constituted by a flat plate made of an insulating material, for example, insulating ceramics such as mica. This cover plate 6 is mounted so as to cover the upper surface 2a of the case 2.
  • the heat radiating plate 7 is constituted by a metal plate, and caulking pieces 7a are respectively provided in a pair of opposite edges of the heat radiating plate 7.
  • the heat radiating plate 7 is so mounted as to cover the upper surface 2a of the case 2 from above the cover plate 6.
  • the caulking pieces 7a provided for the heat radiating plate 7 are caulked, so that the heat radiating plate 7 is fixed to the case 2.
  • the cover plate 6 disposed between the heat radiating plate 7 and the upper surface 2a of the case 2 is also fixed.
  • the PTC elements 3 are elastically interposed firmly between the spring terminal 4 and the plane terminal 5, and the plane terminal 5 is brought into close surface contact with the cover plate 6 by an elastic restoring force of the spring terminal 4.
  • the PTC elements 3 generate heat by energization from the plane terminal 5 and the spring terminal 4.
  • the heat generated is mainly transferred to the plane terminal 5.
  • the plane terminal 5 is not contained in the containing recess portions 8 but disposed between the upper surface 2a of the case 2 and the cover plate 6. Consequently, the size of the plane terminal 5 can be increased in the range in which the requirement of an outer withstand voltage is allowed, thereby to make it possible to take out the heat generated in the PTC elements 3 to the exterior more efficiently by the increase in size.
  • the heat generated in the PTC elements 3 can be efficiently transferred to the heat radiating plate 7, and the mat impregnated with a drug can be efficiently heated by the heat radiating plate 7.
  • the plane terminal 5 and the cover plate 6 which are in a thin plate shape are only interposed between the PTC elements 3 and the heat radiating plate 7. Also from that point, therefore, the heat generated in the PTC elements 3 can be efficiently transferred to the heat radiating plate 7.
  • both the plane terminal 5 and the cover plate 6 are members having simple structures, whose surfaces can be easily smoothed. Consequently, the plane terminal 5 is brought into close surface contact with the cover plate 6 by an urging force of the spring terminal 4. Also from this point, therefore, the heat conducted to the plane terminal 5 is efficiently transferred to the heat radiating plate 7, and the surface temperature of the heat radiating plate 7 does not easily vary.
  • the plurality of plane terminal portions 5a are connected to each other by the narrow connecting pieces 5b. Accordingly, each of the plane terminal portions 5a can be easily deformed independently of the other plane terminal portions 5a.
  • the plane terminal 5 may, in some cases, be brought into close surface contact with the cover plate 6. Even in this case, however, each of the plane terminal portions 5a can be easily deformed depending on the shape of the cover plate 6, so that adhesive properties between the cover plate 6 and each of the plane terminal portions 5a is not degraded.
  • the narrow portion 10a is so bent as to be apart from the inner wall of the containing portion 11, thereby to prevent the narrow portion 10a from being brought into contact with the case 2. Accordingly, heat generated when an overcurrent flows into the narrow portion 10a is not radiated through the case 2, so that the problem that an overcurrent fusing time period is extended due to radiation of heat to the case 2 does not easily arise.
  • the present invention may be applied to a positive temperature coefficient thermistor device containing not less than three PTC elements.
  • the number of spring terminal portions of the spring terminal and the number of plane terminal portions of the plate terminal are increased depending on the number of PTC elements.
  • the heat radiating plate 7 is fixed to the case 2 by caulking the caulking pieces 7a
  • the heat radiating plate 7 and the case 2 may be fixed to each other by other known fixing means besides utilizing the above described caulking pieces.
  • the heat radiating plate 7 may be fixed to the case 2 by providing an engaging piece on the heat dissipating plate 7, providing an engaging recess portion with which the engaging piece can be engaged on the side surface of the case 2, and fitting the engaging piece on the heat radiating plate 7 in the engaging recess portion of the case 2.
  • the heat radiating plate 7 may be bonded to the case 7 and the cover plate 6 using adhesives which is superior in heat resistance.
  • the heat radiating plate 7 and the case 2 may be fixed to each other using, for example, a bolt and a nut.

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Catching Or Destruction (AREA)
  • Thermistors And Varistors (AREA)
  • Details Of Resistors (AREA)
  • Resistance Heating (AREA)
EP19930113532 1992-08-27 1993-08-24 Positive temperature coefficient thermistor device Expired - Lifetime EP0584800B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP60401/92U 1992-08-27
JP6040192U JPH0623205U (ja) 1992-08-27 1992-08-27 正特性サーミスタ装置

Publications (3)

Publication Number Publication Date
EP0584800A2 EP0584800A2 (en) 1994-03-02
EP0584800A3 EP0584800A3 (en) 1995-01-18
EP0584800B1 true EP0584800B1 (en) 1998-02-25

Family

ID=13141113

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19930113532 Expired - Lifetime EP0584800B1 (en) 1992-08-27 1993-08-24 Positive temperature coefficient thermistor device

Country Status (4)

Country Link
EP (1) EP0584800B1 (ja)
JP (1) JPH0623205U (ja)
KR (1) KR960015944B1 (ja)
ES (1) ES2112363T3 (ja)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2114495B1 (es) * 1996-05-30 1999-02-01 Dbk Espana Sa Dispositivo calefactor de tabletas para la vaporizacion de materias activas.
ES2241799T3 (es) * 2001-03-13 2005-11-01 Zobele España, S.A. Dispositivo de calefactor multiuso para evaporacion de sustancias activas.
ES2396405B1 (es) 2011-05-13 2013-12-26 Zyxtudio Diseño E Innovacion S.L. Dispositivo vaporizador mejorado.

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4728779A (en) * 1985-09-27 1988-03-01 Tdk Corporation PTC heating device
JP2556877B2 (ja) * 1988-03-10 1996-11-27 株式会社村田製作所 正特性サーミスタ装置
JPH02248001A (ja) * 1989-03-22 1990-10-03 Matsushita Electric Ind Co Ltd 正特性サーミスタ装置
JPH0831353B2 (ja) * 1989-12-15 1996-03-27 株式会社村田製作所 正特性サーミスタ装置
JP2529252Y2 (ja) * 1990-04-05 1997-03-19 日本油脂株式会社 正特性サーミスタ装置
JPH04206288A (ja) * 1990-11-29 1992-07-28 Murata Mfg Co Ltd 正特性サーミスタ装置

Also Published As

Publication number Publication date
KR960015944B1 (ko) 1996-11-25
JPH0623205U (ja) 1994-03-25
ES2112363T3 (es) 1998-04-01
EP0584800A3 (en) 1995-01-18
EP0584800A2 (en) 1994-03-02

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