EP0143091A1 - Induktionsheizgerät für ringförmige Produkte, insbesondere Rollenlager - Google Patents

Induktionsheizgerät für ringförmige Produkte, insbesondere Rollenlager Download PDF

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Publication number
EP0143091A1
EP0143091A1 EP19840850307 EP84850307A EP0143091A1 EP 0143091 A1 EP0143091 A1 EP 0143091A1 EP 19840850307 EP19840850307 EP 19840850307 EP 84850307 A EP84850307 A EP 84850307A EP 0143091 A1 EP0143091 A1 EP 0143091A1
Authority
EP
European Patent Office
Prior art keywords
switch
ptc
article
heating
primary coil
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.)
Granted
Application number
EP19840850307
Other languages
English (en)
French (fr)
Other versions
EP0143091B1 (de
Inventor
Carsten Aronsson
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.)
SPM Instrument AB
Original Assignee
SPM Instrument AB
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 SPM Instrument AB filed Critical SPM Instrument AB
Publication of EP0143091A1 publication Critical patent/EP0143091A1/de
Application granted granted Critical
Publication of EP0143091B1 publication Critical patent/EP0143091B1/de
Expired 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
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/10—Induction heating apparatus, other than furnaces, for specific applications
    • H05B6/101—Induction heating apparatus, other than furnaces, for specific applications for local heating of metal pieces
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F13/00—Apparatus or processes for magnetising or demagnetising
    • H01F13/006—Methods and devices for demagnetising of magnetic bodies, e.g. workpieces, sheet material
    • 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
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/06—Control, e.g. of temperature, of power

Definitions

  • the invention relates to an induction heater for heating annular articles, particularly roller-bearings, which comprises a U-shaped transformer core provided with a primary coil and a magnetic yoke which is designed to close a magnetic circuit through the transformer core and to have fitted thereonto an annular article which functions as a single-turn secondary coil for heating through an induced current, and further comprising means for coupling the primary coil to an alternating current mains network and means for gradually decreasing the current from said mains network through the primary coil, so as to demagnetize the annular article.
  • Such induction heaters are known to the art and are marketed by a number of manufacturers, for example Firma Grainer of Switzerland. They are primarily used when wishing to heat ball bearings or some other kind of ring-shaped article, in order to mount the same on a shaft and obtain a shrink-fit on said shaft as the article cools.
  • the annular article is made of a ferromagnetic material, the article must normally be demagnetized, which is effected by allowing the alternating current conducted through the primary coil to decrease gradually down towards zero.
  • phase-angle controlled, electric semi-conductor valves (triacs, thyristors) generally emit radio interference signals, which can often be particularly troublesome.
  • An object of the invention is to eliminate these disadvantages. Another object is to provide a simple and inexpensive construction in respective of those circuits which are intended to be active in the reduction of current for the demagnetizing function.
  • the coupling means and the means for gradually reducing the current include a switch which is connected in series to the primary coil and a PTC-resistor which is connected in parallel with said switch and which has a resistance which is low at room temperature, less than about 20 ohms, and a resistance which when heated in response to load, is at least 100 times greater.
  • PTC-resistors are a type of resistor whose resistance increases with temperature. They are available on the market and are normally specified by their resistance value at room temperature and the so-called switch temperature, at which temperature the resistance increases quite strongly at relatively small relative changes in temperature.
  • the operating mode of the invention is as follows.
  • the primary coil is initially connected, via the switch, which is closed, directly to the mains network (50 or 60 Hz; e.g. 220 or 110 v), wherewith the transformer induces in the annular article a current which produces heat, as a result of the inherent resistance of the article.
  • the article is heated to the extent desired, by suitably determining the duration of the heating phase.
  • the article is demagnetized, which is the phase in which the present invention becomes operative.
  • the heated article is magnetized in alternate directions during successive half-periods of the mains frequency, with progressively reduced amplitudes, causing demagnetization in the same way as when the current is decreased in the known heating methods.
  • the switch is suitably arranged to co-act with a timing device which breaks the switch after a given period of time has lapsed, this length of time being determined in accordance with the size of the article to be heated, the shape of the article and other properties thereof, and in accordance with the desired final temperature.
  • the switch consists of a pair of contacts in a relay.
  • the circuit may incorporate, for example, a signal lamp which lights up when the heating phase is completed.
  • this heating phase can take several minutes, during which time the operator may not have the whole of his attention concentrated on the heater.
  • Figure 1 illustrates schematically a transformer construction which includes a U-shaped transformer core 1 and a magnetic yoke 3, which can be removed to allow an annular metal article to be heated, such as a ball bearing (not shown), to be fitted thereonto.
  • a primary coil 2 comprises a winding of 260 turns and is dimensioned for a current of 10-15 A.
  • the transformer itself includes about 12 kg of transformer plate (for 110 V the number of turns is half this number and the current twice as strong).
  • Mains current is passed from a master switch (not shown), through the coil 2 via a switch 4, which is a relay, whose coil current is controlled by a timing circuit T with adjustable switch-in time.
  • a mechanical clock or an electronic clock e.g. powered with mains frequency, which is preferred.
  • a PTC-resistor 5, 5' Connected in parallel with the switch 4 in a respective branch line is a PTC-resistor 5, 5', each in series with a respective switch 7 and 8 effective in triggering said resistors alternately, these switches being in the form of triacs.
  • the switch 4 When using the transformer, the switch 4 is first closed for a given length of time of from 0.5 to 10 mins. and is then broken. One of the triacs 7, 8 is conductive. When the switch is broken, the current will flow via the one PTC-resistor, which soon becomes so hot that the current therethrough becomes progressively negligible.
  • PTC-resistors of the make ITT from the company Multi- komponent AB
  • each in the form of two parallel-coupled resistors which when cold each have a resistance of 10 ohm and thus together a resistance of 5 ohm.
  • a small drop in voltage soon occurs and the resistors become hot and the resistances thereof quickly increase to several kilo-ohms.
  • the PTC-resistors had a switch temperature of 115°C.
  • the Figure 1 embodiment also includes a lamp 9, which r lights-up when the heating phase is terminated.
  • FIG. 2 and 3 The detailed circuit diagram shown in Figures 2 and 3 is largely self-explanatory and incorporates conventional components. It will be observed that a voltage divider is placed over the primary coil and its output C is coupled to a circuit which via firing output terminals D and E selects either of the triacs 7 and 8 to be conductive next and to extinguish the conductive triac when the voltage across the primary coil 2 has fallen, and which further causes firing of a light diode 9 upon termination of the demagnetizing phase.
  • An electronic clock circuit is supplied at B with an alternating current of 50-periods and, at a point in time determined by the setting of a potentiometer 10, opens the switching contact of the relay 4 via a signal A. Since such circuit diagrams are fully obvious to the electronics engineer, the information given above is deemed quite sufficient to render the switching circuit readily understandable.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • General Induction Heating (AREA)
  • Control Of Resistance Heating (AREA)
EP19840850307 1983-10-21 1984-10-18 Induktionsheizgerät für ringförmige Produkte, insbesondere Rollenlager Expired EP0143091B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8305807A SE439718B (sv) 1983-10-21 1983-10-21 Induktionsvermare for vermning av ringformade produkter, serskilt rullningslager
SE8305807 1983-10-21

Publications (2)

Publication Number Publication Date
EP0143091A1 true EP0143091A1 (de) 1985-05-29
EP0143091B1 EP0143091B1 (de) 1989-01-18

Family

ID=20353002

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19840850307 Expired EP0143091B1 (de) 1983-10-21 1984-10-18 Induktionsheizgerät für ringförmige Produkte, insbesondere Rollenlager

Country Status (3)

Country Link
EP (1) EP0143091B1 (de)
DE (1) DE3476314D1 (de)
SE (1) SE439718B (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0434204A1 (de) * 1989-12-18 1991-06-26 Feeney, Charles Heizen von Lagern und dergleichen
US5248865A (en) * 1989-12-18 1993-09-28 Tyler George W Apparatus for induction heating of bearings or the like
WO2010037414A1 (en) 2008-09-30 2010-04-08 Aktiebolaget Skf Bearing heater
CN102280237A (zh) * 2010-06-11 2011-12-14 吴昌德 一种调节电阻阻值的方法
CN105118606A (zh) * 2015-09-11 2015-12-02 浙江大学 用于在线消除电磁式电流互感器剩磁的退磁电路及方法
US9810113B2 (en) 2015-03-09 2017-11-07 The Boeing Company Engine lubrication heating system

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2942162A (en) * 1953-07-02 1960-06-21 Maximilian C Becker Demagnetizers and methods for demagnetizing
DE1097059B (de) * 1959-10-12 1961-01-12 Kugelfischer G Schaefer & Co Verfahren zum elektrisch-induktiven Erwaermen von Metallringen
US3845442A (en) * 1971-02-03 1974-10-29 Nichicon Capacitor Ltd Automatic degaussing device
DE2812166A1 (de) * 1978-01-18 1979-07-19 Greiner Electronic Ag Verfahren und einrichtung zum induktiven erhitzen elektrisch leitender werkstuecke
DE2914304A1 (de) * 1978-04-11 1979-10-25 Vertina Anstalt Verfahren zum induktiven erwaermen von metallischen werkstuecken

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2942162A (en) * 1953-07-02 1960-06-21 Maximilian C Becker Demagnetizers and methods for demagnetizing
DE1097059B (de) * 1959-10-12 1961-01-12 Kugelfischer G Schaefer & Co Verfahren zum elektrisch-induktiven Erwaermen von Metallringen
US3845442A (en) * 1971-02-03 1974-10-29 Nichicon Capacitor Ltd Automatic degaussing device
DE2812166A1 (de) * 1978-01-18 1979-07-19 Greiner Electronic Ag Verfahren und einrichtung zum induktiven erhitzen elektrisch leitender werkstuecke
DE2914304A1 (de) * 1978-04-11 1979-10-25 Vertina Anstalt Verfahren zum induktiven erwaermen von metallischen werkstuecken

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0434204A1 (de) * 1989-12-18 1991-06-26 Feeney, Charles Heizen von Lagern und dergleichen
US5248865A (en) * 1989-12-18 1993-09-28 Tyler George W Apparatus for induction heating of bearings or the like
WO2010037414A1 (en) 2008-09-30 2010-04-08 Aktiebolaget Skf Bearing heater
CN102171471A (zh) * 2008-09-30 2011-08-31 Skf公司 轴承加热器
EP2728965A1 (de) 2008-09-30 2014-05-07 Aktiebolaget SKF Lagererhitzer
US9012819B2 (en) 2008-09-30 2015-04-21 Aktiebolaget Skf Bearing heater
CN102280237A (zh) * 2010-06-11 2011-12-14 吴昌德 一种调节电阻阻值的方法
US9810113B2 (en) 2015-03-09 2017-11-07 The Boeing Company Engine lubrication heating system
CN105118606A (zh) * 2015-09-11 2015-12-02 浙江大学 用于在线消除电磁式电流互感器剩磁的退磁电路及方法

Also Published As

Publication number Publication date
DE3476314D1 (en) 1989-02-23
SE439718B (sv) 1985-06-24
SE8305807L (sv) 1985-04-22
EP0143091B1 (de) 1989-01-18
SE8305807D0 (sv) 1983-10-21

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