GB2125832A - An arrangement for cooling the edges of cam-followers during hardening - Google Patents

An arrangement for cooling the edges of cam-followers during hardening Download PDF

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Publication number
GB2125832A
GB2125832A GB08321205A GB8321205A GB2125832A GB 2125832 A GB2125832 A GB 2125832A GB 08321205 A GB08321205 A GB 08321205A GB 8321205 A GB8321205 A GB 8321205A GB 2125832 A GB2125832 A GB 2125832A
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GB
United Kingdom
Prior art keywords
cam
cooling
hardened
hardening
follower
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
GB08321205A
Other versions
GB2125832B (en
GB8321205D0 (en
Inventor
Friedhelm Reinke
Edgar Stengel
Hans-Jergen Leisner
Friedhelm Emde
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.)
SMS Elotherm GmbH
Original Assignee
AEG Elotherm 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 AEG Elotherm GmbH filed Critical AEG Elotherm GmbH
Publication of GB8321205D0 publication Critical patent/GB8321205D0/en
Publication of GB2125832A publication Critical patent/GB2125832A/en
Application granted granted Critical
Publication of GB2125832B publication Critical patent/GB2125832B/en
Expired legal-status Critical Current

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Classifications

    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/06—Surface hardening
    • 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
    • C21D9/30—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for crankshafts; for camshafts

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Articles (AREA)
  • Heat Treatments In General, Especially Conveying And Cooling (AREA)

Abstract

An arrangement for cooling the edge portions of the surfaces of cast-iron cam-followers, which are subjected to wear during use, during the hardening of these portions of the cam-follower surfaces by means of a remelting technique, characterised by the provision of water-cooled elements (4) each of which cover an edge portion (7) of the workpiece over a narrow region (8) of that surface of the cam-follower (1) which is being hardened by the remelting technique, which region does not undergo surface melting. The said jaw elements may each bear against a top or a side edge portion of the workpiece. <IMAGE>

Description

SPECIFICATION An arrangement for cooling the edges of camfollowers during hardening This invention relates to an arrangement for cooling the edges of portions of the surfaces of cam-followers, for example rocker arms or similar components, which are subjected to wear when actuated by camsto control the valves of internal combustion engines, the said cooling being applied during hardening of the said portions of the cam-follower surfaces by the remelting technique.
Hitherto cam-followers for controlling the valves on internal combustion engines have been manufactured from steel or cast-iron, and have been provided with a hardened layer at least on the surface regions which are subjected to wear.
The hardening process usually has been carried out by an induction heating method, with subsequent quenching in air or water to effect transformation hardening or precipitation hardening, or by a heat treatment involving a change in the chemical composition, for example a carbo-nitriding treatment.
Recently there has been a tendency towards using cast-iron follower arms which have been hardened by the remelting technique using socalled TIG welding equipment, on those portions of their surfaces which are subjected to wear, since ledeburitic layers thus produced possess good antifrictional properties. In order to enhance the wear resistance over the entire surface which, on the follower-lever, is subjected to wear, the zone to which the hardening treatment by the remelting technique is applied had to extend as close as possible to the edges of that portion of the surface of the follower-lever which was to be hardened.With this technique however, the problem arose that the portions of the surface which were hardened by the remelting technique underwent severe distortion, and the subsequent grinding operation necessary in order to achieve the desired dimensions resulted in a portion of the hardened surface zone being ground off again.
The present invention is directed to the provision of an arrangement for cooling the edges of the cam-followers during hardening by remelting, this arrangement inhibiting both the distortion of the cam-followers during the hardening treatment and the formation of hardening cracks in the hardened zone, while offering the possibility of minimising the amount of oversizing which is necessary to allow for grinding losses.
To this end, the invention provides an arrangement for cooling the edge portions of the surfaces of cast-iron cam-followers which are subjected to wear during use, while cooling is effected during the hardening of these portions of the cam-follower surfaces by means of a remelting technique, characterised by the provision of water-cooled elements each of which cover an edge portion of the workpiece over a narrow region of that surface of the cam-follower which is being hardened by the remelting technique, which region does not undergo surface melting.
By intensive cooling of the edges in a narrow region on those portions of the surface of a camfollower which are being hardened by the remelting technique, the arrangement according to the invention inhibits distortion while additionally preventing the formation of hardening cracks and in the design according to Claim 1, provides the edges with protection from the remelting electrode.
The water-cooled cooling jaws, which are composed in particular of copper, may cover upper edge portion on that surface of the cam-follower which is to be hardened by the remelting technique, along the edges, over a narrow region.
In a particular embodiment they are pressed against the side walls to cover side edge portions.
In this manner, only a narrow edge region which is not hardened by remelting is created on those portions of the surface of the cam-follower workpiece, and a hardened zone possessing the greatest possible width is thereby created.
The invention is described in more detail with reference to the accompanying drawing, of which Figure 1 shows diagrammatically in crosssection the cooling of the edges of the camfollower, Figure 2 shows an alternative design.
In the drawing a TIG welding torch 2 produces a zone 3 which becomes hardened by remelting, on a surface of the cam-follower 1 which is subjected to wear effects.
In the design according to Figure 1, watercooled cooling jaws 4 containing passages for water coolant rest on the surface which is being hardened by the remelting technique, along the edges 7 of the follower-lever 1 so as to cover a narrow top edge region 8 so that this does not undergo surface melting.
In the design according to Figure 2, the cooling jaws 4 rest against the side walls 6 of the camfollower 1, so as to cover a narrow side edge region 8 extending from the lower edges 7, and conduct heat away from the edge region so that this does not undergo surface melting.
The cooling jaws can be designed so that they either extend along the entire hardening zone or cover only a shorter portion and are moved in synchronism with the TIG welding torch 2.
1. An arrangement for cooling the edge portions of the surfaces of cast-iron camfollowers, which are subjected to wear during use, while cooling is effected during the hardening of these portions of the cam-follower surfaces by means of a remelting technique, characterised by the provision of water-cooled elements (4) each of which cover an edge portion (7) of the workpiece over a narrow region (8) of that surface of the cam-follower (1) which is being hardened by the remelting technique, which region does not undergo surface melting.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION An arrangement for cooling the edges of camfollowers during hardening This invention relates to an arrangement for cooling the edges of portions of the surfaces of cam-followers, for example rocker arms or similar components, which are subjected to wear when actuated by camsto control the valves of internal combustion engines, the said cooling being applied during hardening of the said portions of the cam-follower surfaces by the remelting technique. Hitherto cam-followers for controlling the valves on internal combustion engines have been manufactured from steel or cast-iron, and have been provided with a hardened layer at least on the surface regions which are subjected to wear. The hardening process usually has been carried out by an induction heating method, with subsequent quenching in air or water to effect transformation hardening or precipitation hardening, or by a heat treatment involving a change in the chemical composition, for example a carbo-nitriding treatment. Recently there has been a tendency towards using cast-iron follower arms which have been hardened by the remelting technique using socalled TIG welding equipment, on those portions of their surfaces which are subjected to wear, since ledeburitic layers thus produced possess good antifrictional properties. In order to enhance the wear resistance over the entire surface which, on the follower-lever, is subjected to wear, the zone to which the hardening treatment by the remelting technique is applied had to extend as close as possible to the edges of that portion of the surface of the follower-lever which was to be hardened.With this technique however, the problem arose that the portions of the surface which were hardened by the remelting technique underwent severe distortion, and the subsequent grinding operation necessary in order to achieve the desired dimensions resulted in a portion of the hardened surface zone being ground off again. The present invention is directed to the provision of an arrangement for cooling the edges of the cam-followers during hardening by remelting, this arrangement inhibiting both the distortion of the cam-followers during the hardening treatment and the formation of hardening cracks in the hardened zone, while offering the possibility of minimising the amount of oversizing which is necessary to allow for grinding losses. To this end, the invention provides an arrangement for cooling the edge portions of the surfaces of cast-iron cam-followers which are subjected to wear during use, while cooling is effected during the hardening of these portions of the cam-follower surfaces by means of a remelting technique, characterised by the provision of water-cooled elements each of which cover an edge portion of the workpiece over a narrow region of that surface of the cam-follower which is being hardened by the remelting technique, which region does not undergo surface melting. By intensive cooling of the edges in a narrow region on those portions of the surface of a camfollower which are being hardened by the remelting technique, the arrangement according to the invention inhibits distortion while additionally preventing the formation of hardening cracks and in the design according to Claim 1, provides the edges with protection from the remelting electrode. The water-cooled cooling jaws, which are composed in particular of copper, may cover upper edge portion on that surface of the cam-follower which is to be hardened by the remelting technique, along the edges, over a narrow region. In a particular embodiment they are pressed against the side walls to cover side edge portions. In this manner, only a narrow edge region which is not hardened by remelting is created on those portions of the surface of the cam-follower workpiece, and a hardened zone possessing the greatest possible width is thereby created. The invention is described in more detail with reference to the accompanying drawing, of which Figure 1 shows diagrammatically in crosssection the cooling of the edges of the camfollower, Figure 2 shows an alternative design. In the drawing a TIG welding torch 2 produces a zone 3 which becomes hardened by remelting, on a surface of the cam-follower 1 which is subjected to wear effects. In the design according to Figure 1, watercooled cooling jaws 4 containing passages for water coolant rest on the surface which is being hardened by the remelting technique, along the edges 7 of the follower-lever 1 so as to cover a narrow top edge region 8 so that this does not undergo surface melting. In the design according to Figure 2, the cooling jaws 4 rest against the side walls 6 of the camfollower 1, so as to cover a narrow side edge region 8 extending from the lower edges 7, and conduct heat away from the edge region so that this does not undergo surface melting. The cooling jaws can be designed so that they either extend along the entire hardening zone or cover only a shorter portion and are moved in synchronism with the TIG welding torch 2. CLAIMS
1. An arrangement for cooling the edge portions of the surfaces of cast-iron camfollowers, which are subjected to wear during use, while cooling is effected during the hardening of these portions of the cam-follower surfaces by means of a remelting technique, characterised by the provision of water-cooled elements (4) each of which cover an edge portion (7) of the workpiece over a narrow region (8) of that surface of the cam-follower (1) which is being hardened by the remelting technique, which region does not undergo surface melting.
2. An arrangement according to Claim 1, wherein said jaw elements each bear against a top edge portion of the workpiece.
3. An arrangement according to Claim 2, wherein said jaw elements each bear against a side edge portion of the workpiece.
4. An arrangement according to Claim 1, substantially as hereinbefore described and illustrated in Figure 1 or Figure 2 of the accompanying drawing.
GB08321205A 1982-08-26 1983-08-05 An arrangement for cooling the edges of cam-followers during hardening Expired GB2125832B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19823231774 DE3231774C1 (en) 1982-08-26 1982-08-26 Device for cooling the edges during remelt hardening of cam followers

Publications (3)

Publication Number Publication Date
GB8321205D0 GB8321205D0 (en) 1983-09-07
GB2125832A true GB2125832A (en) 1984-03-14
GB2125832B GB2125832B (en) 1985-12-11

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB08321205A Expired GB2125832B (en) 1982-08-26 1983-08-05 An arrangement for cooling the edges of cam-followers during hardening

Country Status (4)

Country Link
JP (1) JPS5959830A (en)
DE (1) DE3231774C1 (en)
FR (1) FR2532328B1 (en)
GB (1) GB2125832B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2174319B (en) * 1985-02-21 1989-05-24 Toyota Motor Co Ltd Cylinder head of cast aluminum alloy for internal combustion engines and method of making same

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5980723A (en) * 1982-11-01 1984-05-10 Mitsubishi Motors Corp White pig iron hardening device for sliding surface of cam
JPS61246320A (en) * 1985-03-01 1986-11-01 Toyota Motor Corp Manufacture of remelted and chilled camshaft
DE3916684A1 (en) * 1989-05-23 1990-11-29 Opel Adam Ag Re-melting surface hardening process esp. for cam shaft or drag lever - has central and border regions heated at different times or using geometrical displacement to minimise surface deformation
DE4205801C1 (en) * 1992-02-26 1993-07-15 Aeg-Elotherm Gmbh, 5630 Remscheid, De
DE4224264C1 (en) * 1992-07-23 1993-06-09 Aeg-Elotherm Gmbh, 5630 Remscheid, De Remelting of workpiece surface - by reducing carbon@ content in parts where remelting will not occur and directing an arc, electron, plasma or laser beam onto the surface

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR807429A (en) * 1935-06-20 1937-01-12 Ig Farbenindustrie Ag Process for surface hardening of metal parts and equipment specific to the execution of this process
GB502152A (en) * 1936-09-10 1939-03-10 Werner Theodor Schaurte Process of and apparatus for effecting local hardening of mass-production articles
DE2232124A1 (en) * 1972-06-30 1974-01-10 Daimler Benz Ag Surface hardening - eg of rotary piston surfaces for increased resistan-ce to wear and tear, by charge carrier treatment
DE2742597C3 (en) * 1977-09-22 1980-02-07 Audi Nsu Auto Union Ag, 7107 Neckarsulm Camshaft for piston engines and work machines, preferably reciprocating internal combustion engines

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2174319B (en) * 1985-02-21 1989-05-24 Toyota Motor Co Ltd Cylinder head of cast aluminum alloy for internal combustion engines and method of making same

Also Published As

Publication number Publication date
DE3231774C1 (en) 1983-04-07
GB2125832B (en) 1985-12-11
FR2532328B1 (en) 1986-03-21
FR2532328A1 (en) 1984-03-02
JPS6342689B2 (en) 1988-08-25
JPS5959830A (en) 1984-04-05
GB8321205D0 (en) 1983-09-07

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PCNP Patent ceased through non-payment of renewal fee

Effective date: 19940805