EP0741393A2 - Module thermistance - Google Patents

Module thermistance Download PDF

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Publication number
EP0741393A2
EP0741393A2 EP96104046A EP96104046A EP0741393A2 EP 0741393 A2 EP0741393 A2 EP 0741393A2 EP 96104046 A EP96104046 A EP 96104046A EP 96104046 A EP96104046 A EP 96104046A EP 0741393 A2 EP0741393 A2 EP 0741393A2
Authority
EP
European Patent Office
Prior art keywords
contact
module
temperature monitor
ptc
ptc resistor
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
EP96104046A
Other languages
German (de)
English (en)
Other versions
EP0741393A3 (fr
Inventor
Marcel Hofsäss
Holger Dipl.-Ing. Baumann
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.)
Thermik Geraetebau GmbH
Original Assignee
Thermik Geraetebau GmbH
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 Thermik Geraetebau GmbH filed Critical Thermik Geraetebau GmbH
Publication of EP0741393A2 publication Critical patent/EP0741393A2/fr
Publication of EP0741393A3 publication Critical patent/EP0741393A3/fr
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/50—Means for increasing contact pressure, preventing vibration of contacts, holding contacts together after engagement, or biasing contacts to the open position
    • H01H1/504—Means for increasing contact pressure, preventing vibration of contacts, holding contacts together after engagement, or biasing contacts to the open position by thermal means
    • 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
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H37/00—Thermally-actuated switches
    • H01H37/02—Details
    • H01H37/32—Thermally-sensitive members
    • H01H37/52—Thermally-sensitive members actuated due to deflection of bimetallic element
    • H01H37/54—Thermally-sensitive members actuated due to deflection of bimetallic element wherein the bimetallic element is inherently snap acting

Definitions

  • the present invention relates to a module made of PTC thermistor material, in particular for a clamp contact, with at least two contact surfaces for an electrical connection.
  • the invention further relates to a temperature monitor with a bimetal switching mechanism that switches at excess temperature and a PTC resistor connected to it, which acts in the sense of a self-holding function.
  • Such modules made of PTC thermistor material are generally known, they are e.g. used as heating resistors or as control resistors.
  • the resistance of a PTC thermistor that increases with temperature is used for control purposes or to protect the device heated by the PTC thermistor. Since the thermistor resistance can be adjusted in terms of its temperature output or regulates itself as a result of this temperature-dependent resistance value, which increases with increasing temperature, or irreversible damage to the part to be heated as a result of excess temperatures can be avoided.
  • Such PTC thermistors or PTC semiconductors are e.g. from a sintered barium titanate ceramic, which is subjected to an aftertreatment after the sintering process, since oxide layers form on the surface which prevent direct contact.
  • the ceramic is therefore first ground after the sintering process in order to remove the oxide layers. Subsequently, a metallic contact layer, usually made of aluminum or silver, is applied, which is done either by screen printing or sputtering. The conventional contacting then takes place via these metallic contacting layers.
  • This contacting generally consists of a clamping technique, the contact surfaces provided with a contacting layer being brought into contact with mating contacts and being clamped onto them. It is also known to directly solder or otherwise attach strands to the contacting layers.
  • the known temperature monitor comprises a housing part which is closed by a cover part made of thermistor material and in which the switching mechanism is arranged.
  • the bimetallic switching mechanism comprises, in a known manner, a bimetallic snap disk and a spring washer on which a movable contact part is held. Below the response temperature of the bimetallic snap disc, the movable contact part is pressed by the spring washer against a fixed contact part on the cover, which extends like a rivet through the cover and merges into a head on the outside.
  • the housing part is made of electrically conductive material, so that the switching mechanism creates a conductive connection between the housing part and the head of the fixed contact part at low temperatures.
  • the cover is in conductive connection with both the fixed contact part and with the housing part, so that it is electrically connected in parallel to the switching mechanism.
  • the PTC resistor acts in the sense of a self-holding function.
  • the new module should be able to replace the previous module without changes to the device in which it is used. For example, it should be possible to use the new module with the temperature monitor mentioned at the beginning without having to change the design of the temperature monitor.
  • this object is achieved according to the invention in that at least one of the contact surfaces of the module is ground, and in that the contact is made directly on the ground PTC material without the interposition of contacting layers.
  • the object on which the invention is based is accordingly achieved in that the new module is used as a PTC resistor for the temperature monitor.
  • the contacting layers can be dispensed with if the contact surfaces are only sufficiently ground. At least from a certain operating voltage, which drops in use over the new module, this shows a characteristic curve, that is a voltage-dependent temperature change, which corresponds to the characteristic curve of comparable modules with a contacting layer. Slight changes in the characteristic curve can be compensated for by slightly changing the composition of the PTC thermistor material.
  • the new module can thus be manufactured significantly cheaper than was the case with the known module. Since such components are always initially manufactured with oversize during production and then ground to the actual final dimension, the new component can only be made to measure and prepared for the connection technology in a single operation by using a finer abrasive.
  • the resistance value at the respective operating temperatures and the change in resistance with increasing temperature are decisive for the technical function of such a PTC resistor.
  • the temperature is raised by the current flowing through the resistor, which generates ohmic heat. It follows, however, that as the operating voltage increases, greater heat is generated in the PTC resistor, so that it heats up. As a result of the heating, the resistance value of the module increases in accordance with its characteristic curve, which counteracts the temperature increase.
  • the one or more of the contact surfaces are finely ground, preferably lapped.
  • the advantage here is that a known grinding process, namely lapping, is used to finely grind the contact surfaces.
  • an abrasive for example made of SiC, is used, as was also used originally for the production of PTC thermistor components.
  • the known method however, only rough grinding or finishing was used, which does not lead to the fineness of the grinding of the contact surface required according to the invention. Rather, it was only found in the applicant's company that such finishes enable the PTC thermistor material to be contacted directly.
  • Either just one or more of the contact surfaces can then be finely ground in order to meet different operating conditions. For example, be that the new PTC thermistor module is contacted at one of its contact surfaces with a clamp contact, while one or more other of the contact surfaces are contacted via a soldered connection, which may still require contacting layers.
  • the operating voltage is approximately 100 V and is preferably greater than 110 V.
  • the PTC resistor also serves as a cover part and is pressed against a shoulder of the lower housing part by a flanged edge. Because the PTC thermistor material cannot absorb large pressures, there are special requirements for the thickness of the cover part. This cover part must namely be manufactured with mechanical tolerances in the range of a tenth of a millimeter and less so that it is not destroyed by the flanging process.
  • the new PTC resistor can be manufactured to final dimensions in a single work process; subsequent coatings that change the final dimensions unpredictably are not required. Since the new module also uses a finer grinding process, the overall result is a finer ground surface, which also ensures greater mechanical dimensional accuracy.
  • the PTC resistor is electrically connected in parallel to the bimetal switching mechanism.
  • the PTC resistor with its at least one ground contact surface is in contact with the housing parts, and if the housing part has a flanged edge which clamps the PTC resistor serving as a cover part to the housing part.
  • the advantage here is that the previously used method for assembling the known temperature monitor can be retained, it is only to be used as a cover part of the new module. Since this now has a greater mechanical dimensional accuracy, the flanging now leads to a secure mechanical fit and electrical contact, so that the reject rate is reduced when manufacturing the new temperature monitor.
  • a fixed contact part which is assigned to a movable contact part of the bimetallic switching mechanism, is arranged on the cover part in such a way that it is in contact with a further ground contact surface, preferably being clamped to it.
  • the temperature monitor mentioned at the beginning is e.g. electrically connected in series with a consumer to be protected, which is operated with 220 V alternating voltage or direct voltage. As long as the temperature of the consumer remains within the permissible range, the PTC resistor is short-circuited by the bimetallic switching mechanism, so that the resistance value of the PTC resistor has no influence on the function of the temperature monitor.
  • the bimetal switchgear opens and a large part of the supply voltage drops across the PTC thermistor module.
  • This voltage referred to as the operating voltage, which drops across the new PTC thermistor module, is usually above 100 V, where the characteristic of the new module is so close to that of the old module that the electrical function of the temperature monitor is retained even when the PTC thermistor resistor is replaced.
  • a temperature monitor 10 is shown in FIG. 1 as an example of an application for the new module made of thermistor material.
  • the temperature monitor 10 comprises a pot-shaped housing part 11 and a cover part 12 which closes the housing part 11 and which rests on a circumferential shoulder 13 of the housing part 11.
  • the temperature monitor 10 is closed by a flange 14 which presses the cover part 12 onto the circumferential shoulder 13.
  • a bimetallic switching mechanism 15 which is of conventional construction. It comprises a spring washer 16 which carries a movable contact part 17, over which a bimetallic snap disk 18 is placed.
  • the spring washer 16 is supported on a bottom 19 of the cup-shaped housing part 11 and thus prestresses the movable contact part 17 against a fixed contact part 20 which extends like a rivet through the cover part 12 to the outside, where a head 21 is visible.
  • the switching mechanism 15 has a temperature below its response temperature, so that it is in the closed state. Will the temperature of the switching mechanism 15 increases, the bimetallic snap disk 18 suddenly snaps from the convex shape shown into a concave shape and is supported on the underside of the cover part 12 in such a way that it moves the movable contact part 17 against the force of the spring washer 16 from the fixed Contact part 20 lifts up, as is generally known.
  • Essential for the new temperature monitor 10 is the design of the cover part 12, which is a module 22 made of PTC thermistor material and here acts as a heating resistor 23, i.e. as a PTC resistor 24, which is electrically connected in parallel to the bimetallic switching mechanism 15 and by this in the 1 is short-circuited.
  • Blackening indicates contact surfaces 25, 26 of the block 22 in FIG. 1, which are ground particularly finely because they were subjected to a lapping process with very fine abrasive. Although it is possible to process all the surfaces of the component 22 in such a fine manner, it is sufficient for technical use if the contact surfaces 25, 26 have been subjected to such processing. Due to the fine machining of the surfaces of the component 22, this has very defined mechanical dimensions, so that it is ensured that a corresponding clamping contact on the contact surfaces 25, 26 is reproducibly produced by the flanged edge 14 and the rivet 21.
  • the contact surface 26 is located in the region of the fixed contact part 20 and provides a corresponding electrical connection there conductive connection between the PTC resistor 24 and the contact part 20. Since the mechanical dimensions of the cover part 12 can be set very precisely because of the finely ground surface, the mentioned clamping ensures a firm and thus electrically secure fit of the cover part 12 in the flanged edge 14 or the rivet 21 in the cover part 12, however, mechanical damage to the cover part 12 is avoided.
  • the PTC resistor 24 is connected in parallel with the switching mechanism 15 and is bridged by the switching mechanism 15 when the switching mechanism 15 is closed, so that its resistance value in this switching state is of no importance for the function of the temperature monitor 10. As soon as the switching mechanism 15 opens, however, the PTC resistor 24 lies in the current path between the fixed contact part 20 and the housing part 11. An operating voltage now drops across the PTC resistor 24, which is generally greater than 120 to 130 V. In this voltage range, the component 22 shows a behavior comparable to that of the cover part known from EP-A-0 284 916 mentioned at the beginning, with corresponding contact layers.
  • the PTC resistor 24 Because of its temperature-dependent change in resistance, the PTC resistor 24 now ensures that a corresponding internal temperature is generated by the current now taken over by it, which is sufficiently high to keep the switch mechanism 15 open, but is limited to such an extent that irreversible damage to the switch mechanism 15 can be avoided.
  • FIG. 2 shows a diagram 31 which, for a typical PTC resistor with contacting layers, represents a characteristic curve 32 which represents the change in resistance of this module as a function of the operating temperature U.
  • a further curve 33 can be seen in diagram 31, which represents the corresponding characteristic curve for the new module 22.
  • Both the operating voltage U and the resistance value R are given in arbitrary units in FIG. 2. It can be seen that the characteristic curves 32 and 33 run parallel to one another above an operating voltage 34, it being possible to ensure that the two characteristic curves 32, 33 coincide by appropriate selection of the composition of the PTC thermistor material.
  • the characteristic curves 32, 33 were recorded in the applicant's company for a PTC resistor with a reference temperature of 140 ° to 150 ° C., the black and light squares representing respective measuring points for the characteristic curves 32, 33.
  • the units on the voltage axis corresponded to one volt division and those on the resistance axis corresponded to one division in k ⁇ .
  • an approximately linear R (U) characteristic can be achieved even at voltages lower than the mentioned 120 - 130 V, so that the new components made of PTC thermistor material can not only be used as a heating resistor 23 for temperature monitors, but also also for many other devices that use PTC elements (PTC resistors).
  • PTC resistors PTC resistors
  • the mechanical breakage problems and the clamping contacts the same problems arise as with the temperature monitor 10 discussed here by way of example, so that the use of the new module made of thermistor material also brings the corresponding advantages here.

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  • Thermistors And Varistors (AREA)
EP96104046A 1995-05-03 1996-03-14 Module thermistance Ceased EP0741393A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE1995117310 DE19517310C2 (de) 1995-05-03 1995-05-03 Baustein aus Kaltleitermaterial und Temperaturwächter mit einem solchen Baustein
DE19517310 1995-05-03

Publications (2)

Publication Number Publication Date
EP0741393A2 true EP0741393A2 (fr) 1996-11-06
EP0741393A3 EP0741393A3 (fr) 1997-08-13

Family

ID=7761669

Family Applications (1)

Application Number Title Priority Date Filing Date
EP96104046A Ceased EP0741393A3 (fr) 1995-05-03 1996-03-14 Module thermistance

Country Status (2)

Country Link
EP (1) EP0741393A3 (fr)
DE (1) DE19517310C2 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0887826A2 (fr) * 1997-06-26 1998-12-30 Marcel Hofsäss Interrupteur à commande thermique avec pont de contact
CN104037017A (zh) * 2013-03-04 2014-09-10 马赛尔·P·霍夫萨埃斯 具有绝缘片的温控开关
CN107768193A (zh) * 2017-10-16 2018-03-06 罗铭炽 智能温度感应控制开关

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102011015116A1 (de) 2011-03-22 2012-09-27 Marcel P. HOFSAESS Verfahren zur Herstellung eines temperaturabhängigen Schalters
DE102012103279B3 (de) 2012-04-16 2013-09-12 Marcel P. HOFSAESS Temperaturabhängiger Schalter sowie Verfahren zur Endmontage eines solchen Schalters
DE102012112207B3 (de) 2012-12-13 2014-02-13 Marcel P. HOFSAESS Temperaturabhängiger Schalter
DE102013102006B4 (de) 2013-02-28 2015-03-05 Marcel P. HOFSAESS Temperaturabhängiger Schalter
DE102013108508A1 (de) 2013-08-07 2015-02-12 Thermik Gerätebau GmbH Temperaturabhängiger Schalter
DE102014110260A1 (de) 2014-07-22 2016-01-28 Thermik Gerätebau GmbH Temperaturabhängiger Schalter mit Isolierfolie
DE102015017281B3 (de) 2015-06-30 2021-09-23 Thermik Gerätebau GmbH Temperaturabhängiger Schalter mit Isolierscheibe und elektronische Schaltung
DE102015110509B4 (de) 2015-06-30 2019-03-28 Thermik Gerätebau GmbH Temperaturabhängiger Schalter mit lsolierscheibe und elektronische Schaltung mit einemauf einer Leiterplatte montierten, temperaturabhängigen Schalter
DE102015114248B4 (de) 2015-08-27 2019-01-17 Marcel P. HOFSAESS Temperaturabhängiger Schalter mit Schneidgrat
EP3270401B8 (fr) 2016-07-11 2019-06-26 Thermik Gerätebau GmbH Commutateur thermique doté de vitre isolante
DE102018130078B4 (de) 2018-11-28 2020-10-15 Marcel P. HOFSAESS Temperaturabhängiger Schalter
US11195679B2 (en) 2018-11-28 2021-12-07 Marcel P. HOFSAESS Temperature-dependent switch
DE102019111279B4 (de) * 2019-05-02 2020-11-12 Marcel P. HOFSAESS Temperaturabhängiger Schalter
DE102019112581B4 (de) 2019-05-14 2020-12-17 Marcel P. HOFSAESS Temperaturabhängiger Schalter

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4357590A (en) * 1979-08-28 1982-11-02 U.S. Philips Corporation Composite thermistor component
EP0284916A2 (fr) * 1987-03-31 1988-10-05 Ulrika Hofsäss Thermostat avec un boîtier
US5142265A (en) * 1990-04-05 1992-08-25 Nippon Oil & Fats Co., Ltd. Positive temperature coefficient thermistor device
JPH06215904A (ja) * 1993-01-21 1994-08-05 Tdk Corp 複合型正特性サーミスタ装置
EP0696810A1 (fr) * 1994-08-10 1996-02-14 Thermik Gerätebau GmbH ContrÔleur de température

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE553302C (de) * 1929-11-22 1932-06-24 Le Carbone Sa Anschlusskappe fuer Widerstandsstaebe
CH201924A (de) * 1936-12-23 1938-12-31 Haemmerle Fa F M Einrichtung an Webschützenspindeln zum Festhalten des Kopses.
DE1232510B (de) * 1963-11-19 1967-01-12 Erich Weber Verfahren zur Metallisierung von Keramikkoerpern fuer elektrotechnische Bauelemente
DE3900787A1 (de) * 1989-01-12 1990-07-19 Siemens Ag Verfahren zur herstellung eines keramischen elektrischen bauelementes

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4357590A (en) * 1979-08-28 1982-11-02 U.S. Philips Corporation Composite thermistor component
EP0284916A2 (fr) * 1987-03-31 1988-10-05 Ulrika Hofsäss Thermostat avec un boîtier
US5142265A (en) * 1990-04-05 1992-08-25 Nippon Oil & Fats Co., Ltd. Positive temperature coefficient thermistor device
JPH06215904A (ja) * 1993-01-21 1994-08-05 Tdk Corp 複合型正特性サーミスタ装置
EP0696810A1 (fr) * 1994-08-10 1996-02-14 Thermik Gerätebau GmbH ContrÔleur de température

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 018, no. 573 (E-1624), 2.November 1994 & JP 06 215904 A (TDK CORP), 5.August 1994, *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0887826A2 (fr) * 1997-06-26 1998-12-30 Marcel Hofsäss Interrupteur à commande thermique avec pont de contact
EP0887826A3 (fr) * 1997-06-26 1999-06-09 Marcel Hofsäss Interrupteur à commande thermique avec pont de contact
CN104037017A (zh) * 2013-03-04 2014-09-10 马赛尔·P·霍夫萨埃斯 具有绝缘片的温控开关
CN104037017B (zh) * 2013-03-04 2017-10-24 马赛尔·P·霍夫萨埃斯 具有绝缘片的温控开关
CN107768193A (zh) * 2017-10-16 2018-03-06 罗铭炽 智能温度感应控制开关

Also Published As

Publication number Publication date
DE19517310A1 (de) 1996-11-14
EP0741393A3 (fr) 1997-08-13
DE19517310C2 (de) 1999-12-23

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