EP0064367B1 - Verfahren zum induktiven Erhitzen von Ventilsitzeinlagen - Google Patents

Verfahren zum induktiven Erhitzen von Ventilsitzeinlagen Download PDF

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Publication number
EP0064367B1
EP0064367B1 EP82302088A EP82302088A EP0064367B1 EP 0064367 B1 EP0064367 B1 EP 0064367B1 EP 82302088 A EP82302088 A EP 82302088A EP 82302088 A EP82302088 A EP 82302088A EP 0064367 B1 EP0064367 B1 EP 0064367B1
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EP
European Patent Office
Prior art keywords
valve seat
insert
inductor
energizing
engine component
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
Application number
EP82302088A
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English (en)
French (fr)
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EP0064367A3 (en
EP0064367A2 (de
Inventor
Norbert Raymond Balzer
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.)
Park Ohio Industries Inc
Original Assignee
Park Ohio Industries Inc
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 Park Ohio Industries Inc filed Critical Park Ohio Industries Inc
Priority to AT82302088T priority Critical patent/ATE17814T1/de
Publication of EP0064367A2 publication Critical patent/EP0064367A2/de
Publication of EP0064367A3 publication Critical patent/EP0064367A3/en
Application granted granted Critical
Publication of EP0064367B1 publication Critical patent/EP0064367B1/de
Expired legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L3/00—Lift-valve, i.e. cut-off apparatus with closure members having at least a component of their opening and closing motion perpendicular to the closing faces; Parts or accessories thereof
    • F01L3/22—Valve-seats not provided for in preceding subgroups of this group; Fixing of valve-seats
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/0068—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for particular articles not mentioned below

Definitions

  • This invention relates to the art of induction heating and, more particularly, to a method for inductively heating valve seat inserts for an engine component such as an engine head or the like.
  • the invention is particularly applicable to heating exhaust valve seat inserts in a cast aluminum engine component and will be described with particular reference thereto; however, it will be appreciated that the invention has broader applications.
  • valve seats which coact with reciprocating poppet valves for controlling the flow of gases to and from the engine cylinders.
  • the valve seats for the exhaust valves must have extremely high wear characteristics at high engine operating temperatures.
  • the frusto-conical seat surfaces are inductively heated during engine manufacture and then quench hardened by conventional liquid or mass quenching techniques.
  • Induction heating of multiple valve seats in an engine component may be adapted to automatic processing in a single operation where, for example, a plurality of single turn inductors are positioned immediately adjacent the frusto-conically shaped exhaust valve seat.
  • Such apparatus and methods are disclosed in US-E-29,046 and . US-A-3,837,934 to which reference is directed.
  • the inductors are independently movable on a common frame relative to the engine component and are biased toward the valve seats.
  • the frame itself is moved into contact with the engine component so that each inductor contacts the valve seat which it is to heat.
  • the inductors are then locked in position and the frame retracted slightly for purposes of establishing a desired magnetic coupling distance between the inductors and valve seats. After heating, the valve seat -material is quenched.
  • the foregoing patents disclose methods which have provided extremely good results when induction heating ferrous exhaust valve seats in cast iron engine components.
  • the present invention provides an alternative method of hardening a valve seat on a ferrous valve seat insert located in a bore of an engine component using inductive heating, in which the above-mentioned problems caused by heating the valve seat surface to its hardening temperature whilst the insert is located in the engine component bore are overcome by the controlled application of high frequency power in the inductive heating of the valve seat surface.
  • the present invention includes a method of hardening a frusto-conical valve seat on a ferrous valve seat insert retained with a pressure fit within a bore of an engine component said method comprising the steps of:
  • the invention is especially advantageous where the engine component is non-ferrous particularly, as stated above, where the engine component is aluminum.
  • the invention also includes a method of hardening a frusto-conical valve seat on a ferrous valve seat insert coaxially fixed in a bore of an aluminum engine component, said method comprising the steps of:
  • FIGURE 1 shows an induction heating device A disposed in operative communication with a cast aluminum engine component B. Specific details of the features and operation of induction heating device A are disclosed in detail in our US-E-29046.
  • engine component B includes at least one exhaust passageway 10 having an annular valve seat insert 12 formed of cast iron and closely disposed coaxially within a recessed cylindrical exhaust port 14.
  • a guide opening or port 16 is coaxial with exhaust port 14 and receives the stem of a conventional poppet valve (not shown) when the engine is assembled.
  • Annular valve seat insert 12 includes a frusto-conically shaped valve seat surface 30 which is installed into the engine component, machined and thereafter hardened.
  • Insert 12 comprises a standard component typically constructed from steel or cast iron; however, cast iron is preferred because of costs.
  • Installation of insert 12 into the receiving bore at exhaust port 14 may be by any one of a number of conventional methods including, for example, a pressure or force fit and the like. When a pressure fit technique is employed, the insert is normally chilled to obtain some degree of contraction and thereby more readily accommodate installation. Following installation, the insert is fixedly retained in port 14 by opposed forces particularly occurring at interface area 32 between the outer side wall of the insert and the receiving bore side wall. It will be readily appreciated that a plurality of exhaust ports with associated inserts A are typically involved with any engine component Bin the same manner best described in U.S. Pat. No. Re 29.046.
  • induction heating device A includes a generally cylindrical electrically insulated body 40 having a somewhat smaller cylindrical electrically insulated body insert 42 extending coaxially outward from the inner end thereof.
  • a locating pin or nose 44 extends coaxially outward from body insert 42 to accommodate locating the induction heating device coaxially of exhaust port 14 in a known manner.
  • a single turn inductor Interposed between body 40 and body insert 42 of the induction heating device is a single turn inductor generally designated 50.
  • This inductor comprises a split circular ring of copper of generally rectangular cross-section and includes a pair of spaced legs 52, 54 extending therefrom axially through body 40 and outwardly from the body outer end.
  • Inductor 50 as well as legs 52, 54 are hollow and communicate with each other in such fashion to define a continuous fluid passageway therethrough. This passageway accommodates passage of a suitable coolant from a source (not shown) disposed adjacent to or spaced from the overall induction heating device as is known.
  • a power source 60 is operatively connected by leads 62, 64 to inductor 50 as at, for example, legs 52, 54, respectively.
  • the power source comprises an oscillator having an output frequency capability generally in the range of 200-500 kilohertz (kHz) and a power capability of generally between 12-25 kilowatts (kW).
  • kHz kilohertz
  • kW kilowatts
  • the preferred power is approximately 20 kW.
  • the power density is in the general range of 24 to 50 kW/m 2 (3.72 to 7.7 kW/cm 2 ) and is preferably 40 kW/in 2 (6.2 kW/cm 2 ). This is drastically higher than any power density previously used for heating the valve seats of internal combustion engines.
  • a time delay device is advantageously incorporated between leads 62, 64 for turning the power source 60 off after a preselected heating time or interval. This heating time is quite short and less than 1 second.
  • aluminum engine component B will typically have a plurality of exhaust ports 14 which all have similar inserts 12 which are to be inductively heated in a simultaneous manner.
  • Apparatus adapted for this purpose is shown in US-E-29,046 and includes means for causing induction heating device A to be positioned in an associated exhaust port 14 with locating pin 44 coaxially aligning the device relative to the exhaust port.
  • Device A is bottomed out with inductor 50 engaging conical valve seat surface 30 of seat insert 12. Thereafter, the heating device is backed out slightly so that some preselected gap is present between the inductor and frusto-conical valve seat surface 30 to effect a desired coupling relationship therebetween.
  • this gap is generally designated by letter g and comprises a distance of approximately 0.040 inches (1 mm). While this particular gap has been found particularly suitable in most cases where a ferrous valve seat insert disposed in an aluminum engine component is to have a frusto-conical valve seat surface hardened, it will be appreciated that it may be varied somewhat as deemed necessary or appropriate for a specific application of the new method.
  • the side or flat surface 70 of inductor 50 is generally parallel to seat surface 30 and has a width at least slightly greater than that of the seat surface.
  • a high power, low time induction heating method is employed whereby seat surface 30 of seat insert 12 is sufficiently heated to an acceptable depth for purposes of transforming the seat material into the austenitic range for subsequent transformation into the martensitic range.
  • the depth of such transformation is generally designated by the letter d and may comprise a depth of up to approximately 0.035 inches (0.89 mm), although 0.024 inches (0.61 mm) is generally preferred.
  • a relatively shallow reference depth is heated in the seat surface and by using the preferred power of approximately 20 kW to obtain a power density of about 40 kW/in 2 (6.2 kW/cm 2 ), the valve seat is heated to an acceptable transformation temperature at a very rapid rate. Indeed, and when using the preferred ranges noted, it has been found that a time interval of approximately 0.5 seconds will provide entirely satisfactory heating and hardening results to a depth of approximately 0.024 inches (0.61 mm).
  • the seat rings or the entire engine component are subjected to quenching in a manner known in the art. Because heating of seat surfaces 30 is so rapid and is substantially limited to or isolated at these surfaces to a preselected shallow depth, there is no deleterious heating of the whole insert or heat transfer through seat inserts 12. These factors might otherwise adversely affect or alter the close fitting relationship between the seat inserts and exhaust ports. This result represents a substantial improvement over results obtained from prior known techniques in inductively heating valve seats or valve seat inserts.
  • cast iron valve seat inserts have been successfully hardened to a case depth of 0.030 inches (0.76 mm) using a heat cycle of 0.5 seconds with a radio frequency oscillator (400 kHz) and a power density of 40 kW/in 2 (6.2 kW/cm z ).
  • the advantages of using a soft cast iron insert in an aluminum cylinder head rather than a prehardened alloy steel insert resides in the fact that it permits easy machining of the soft cast insert with subsequent hardening of the valve seat by induction hardening techniques. This then achieves the requisite seat durability while, at the same time, yielding considerable improvement by way of increased productivity.
  • Valve seat inserts have also been hardened at a 0.2 second heat time with this new method to approximately the case depth of 0.030 inches (0.76 mm) by using considerably more than 40 kW/in 2 (6.2 kW/cm 2 ) power density. Even though it reduces the tendency to induce heat into the insert, the 0.5 second heating cycle is considered somewhat more tolerable in that it provides a more uniform and constant case depth.
  • the preferred parameters of the subject method using a primary power source having a frequency of approximately 400 kHz and a power of approximately 20 kW with a heating cycle of approximately 0.5 seconds provides a case depth of approximately 0.024 inches (0.61 mm) and a hardness of "58" on the Rockwell C scale in cast iron seat inserts.
  • Prior techniques which typically employ the same frequency at a power of approximately 7 kw with a heating cycle of approximately 7-8 seconds provides a case depth of between 0.050-0.060 inches (1.27-1.52 mm) and a hardness of "58" on the Rockwell C scale.
  • Such parameters, while acceptable for gray cast iron engine components having integral cast iron valve seats simply will not provide suitable results in the environment of cast aluminum engine components utilizing ferrous seat ring inserts.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Thermal Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • Heat Treatment Of Articles (AREA)
  • Details Of Valves (AREA)
  • General Induction Heating (AREA)
  • Lift Valve (AREA)

Claims (10)

1. Verfahren zum Härten eines kegelstumpfförmigen Ventilsitzes (30) an einer aus Eisenwerkstoff bestehenden Ventilsitzeinlage (12), die mit Preßsitz in einer Bohrung eines Motorteils (B) gehalten ist, wobei das Verfahren durch folgende Merkmale gekennzeichnet ist:
(a) Anordnung eines im wesentlichen kreisförmigen Induktors (50) in Nähe der und in Anpassung zu der genannten Einlage (12);
(b) Einstellung der Erregung des genannten Induktors auf eine Frequenz zwischen 200 und 500 kHz, eine ausgewählte Leistung von 12 bis 25 kW, eine Leistungsdichte am Sitz zwischen 24 und 50 kW/in2 (3,72 bis 7,7 kW/cm2) und für eine Zeitspanne unter 1 Sekunde, um das den Ventilsitz bildende Metall bis zu einer vorbestimmten Tiefe in den austenitischen Zustand zu überführen;
(c) Anschließendes Kühlen des Ventilsitzwerkstoffes.
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß der genannte Schritt der Erregung bei einer Frequenz oberhalb 250 kHz durchgeführt wird.
3. Verfahren nach Anspruch 2, dadurch gekennzeichnet, daß der genannte Schritt der Erregung bei einer Erregung von etwa 400 kHz durchgeführt wird.
4. Verfahren nach Anspruch 3, dadurch gekennzeichnet, daß der genannte Schritt der Erregung bei einer Leistung von angenähert 20 kW durchgeführt wird.
5. Verfahren nach Anspruch 3 oder 4, dadurch gekennzeichnet, daß der genannte Schritt der Erregung mit einer Leistungsdichte von 40 kW/in2 (6,2 kW/cm2) durchgeführt wird.
6. Verfahren nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß der genannte Schritt der Erregung mit einer solchen Leistung durchgeführt wird, daß die Leistungsdichte an dem Sitz (30) im Bereich von 25 bis 45 kW/in2 (3,875 bis 6,975 kW/cm2) liegt.
7. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die genannte Induktorerregung das den Ventilsitz bildende Metall auf einer Tiefe von unter 0,035 inch (0,89 mm) in die austenitische Form überführt.
8. Verfahren zum Härten eines kegelstumpfförmigen Ventilsitzes (30) an einer aus Eisenwerkstoff bestehenden Ventilsitzeinlage (12), die koaxial iri einer Bohrung eines Aluminium-Motorteils (B) festgelegt ist, gekennzeichnet durch folgende Verfahrensschritte:
(a) Anordnung eines im wesentlichen kreisförmigen Induktors (50) in Nähe der genannten Einlage (12);
(b) Erregung dieses Induktors (50) mittels einer Hauptstromquelle, die eine Frequenz von mindestens 200 kHz und eine ausgewählte Leistung von mindestens 12 kW hat und eine Leistungsdichte am Sitz von 25 bis 45 kW/in2 (3,875 bis 6,975 kW/cm2) erzeugt;
(c) Aufrechterhaltung des erregten Zustandes am Induktor (50) über eine vorbestimmte Zeitspanne, die ausreicht, um das den Ventilsitz (30) bildende Metall bis zu einer Tiefe, die kleiner ist als 0,035 inch (0,89 mm) in die austenitische Struktur umzuwandeln;
(d) Anschließendes Abkühlen des Ventilsitzwerkstoffes.
9. Verfahren nach Anspruch 8, dadurch gekennzeichnet, daß der genannte Schritt der Erregung bei einer Frequenz im Bereich von 250 bis 500 kHz durchgeführt wird.
10. Verfahren nach Anspruch 8 oder 9, dadurch gekennzeichnet, daß der genannte Schritt der Aufrechterhaltung des erregten Zustandes so durchgeführt wird, daß die Strukturumwandlung in etwa 0,5 Sekunden auf eine vorbestimmte Tiefe von etwa 0,024 inch (0,61 mm) erfolgt.
EP82302088A 1981-05-04 1982-04-23 Verfahren zum induktiven Erhitzen von Ventilsitzeinlagen Expired EP0064367B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT82302088T ATE17814T1 (de) 1981-05-04 1982-04-23 Verfahren zum induktiven erhitzen von ventilsitzeinlagen.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US25985681A 1981-05-04 1981-05-04
US259856 1988-10-19

Publications (3)

Publication Number Publication Date
EP0064367A2 EP0064367A2 (de) 1982-11-10
EP0064367A3 EP0064367A3 (en) 1983-03-30
EP0064367B1 true EP0064367B1 (de) 1986-01-29

Family

ID=22986708

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82302088A Expired EP0064367B1 (de) 1981-05-04 1982-04-23 Verfahren zum induktiven Erhitzen von Ventilsitzeinlagen

Country Status (6)

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EP (1) EP0064367B1 (de)
JP (1) JPS6047884B2 (de)
AT (1) ATE17814T1 (de)
CA (1) CA1187142A (de)
DE (1) DE3268757D1 (de)
MX (1) MX151639A (de)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3373317B2 (ja) * 1995-02-16 2003-02-04 ヤマハ発動機株式会社 シリンダヘッドのバルブシート部構造
JP3380081B2 (ja) * 1995-03-13 2003-02-24 ヤマハ発動機株式会社 バルブシート
DE69606205T2 (de) * 1995-02-28 2000-06-08 Yamaha Motor Co Ltd Zylinderkopf und Verfahren zur Herstellung eines Ventilsitzes
US5778531A (en) * 1995-09-14 1998-07-14 Yamaha Hatsudoki Kabushiki Kaisha Method of manufacturing cylinder head for engine
JPH0979014A (ja) * 1995-09-14 1997-03-25 Yamaha Motor Co Ltd エンジン用シリンダヘッドの製造方法
US5745993A (en) * 1996-02-27 1998-05-05 Yamaha Hatsudoki Kabushiki Kaisha Valve seat
US10774939B2 (en) * 2018-04-12 2020-09-15 Cla-Val Co. Valve with integral insert-cast seat and related method

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1035179B (de) * 1955-05-20 1958-07-31 Saviem Verfahren zur Waermebehandlung von Ventilsitzen
USRE29046E (en) * 1971-06-09 1976-11-23 Park-Ohio Industries, Inc. Method and apparatus for inductively heating valve seats
US3837934A (en) * 1971-06-09 1974-09-24 Park Ohio Industries Inc Method for inductively heating valve seats
DE3175203D1 (en) * 1980-05-08 1986-10-02 Park Ohio Industries Inc Method and apparatus for inductively heating valve seat inserts for hardening the seat surfaces

Also Published As

Publication number Publication date
EP0064367A3 (en) 1983-03-30
DE3268757D1 (en) 1986-03-13
CA1187142A (en) 1985-05-14
ATE17814T1 (de) 1986-02-15
EP0064367A2 (de) 1982-11-10
JPS57194212A (en) 1982-11-29
JPS6047884B2 (ja) 1985-10-24
MX151639A (es) 1985-01-23

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