EP0154787B1 - Verbesserungen in Bezug auf das Giessen - Google Patents

Verbesserungen in Bezug auf das Giessen Download PDF

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Publication number
EP0154787B1
EP0154787B1 EP85100891A EP85100891A EP0154787B1 EP 0154787 B1 EP0154787 B1 EP 0154787B1 EP 85100891 A EP85100891 A EP 85100891A EP 85100891 A EP85100891 A EP 85100891A EP 0154787 B1 EP0154787 B1 EP 0154787B1
Authority
EP
European Patent Office
Prior art keywords
casting
rigid member
mould
elongate rigid
insulating material
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
EP85100891A
Other languages
English (en)
French (fr)
Other versions
EP0154787A1 (de
Inventor
Robert Andrew Williams
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.)
G CLANCEY Ltd
Original Assignee
G CLANCEY 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 G CLANCEY Ltd filed Critical G CLANCEY Ltd
Priority to AT85100891T priority Critical patent/ATE33217T1/de
Publication of EP0154787A1 publication Critical patent/EP0154787A1/de
Application granted granted Critical
Publication of EP0154787B1 publication Critical patent/EP0154787B1/de
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/10—Cores; Manufacture or installation of cores
    • B22C9/101—Permanent cores

Definitions

  • This invention relates to an improved method of casting and more particularly to a method of casting by which an elongate opening is formed in a workpiece during casting.
  • a sand core is constructed and the sand core placed in a mould into which hot molten metal is subsequently cast.
  • sand cores require supporting along their length, otherwise the core tends to sag intermediate its ends.
  • the Lydmet method is unsatisfactory because further operations are required to remove the graphite rod, and graphite rods are lost during casting.
  • a vented rigid metal rod is used as a core in a casting which is covered prior to casting with an incombustible refractory material.
  • the refractory material is permeable to allow gases produced during casting to escape into the vent of the core rod.
  • the cast metal is chilled where it contacts the cool metal core rod, thereby hardening the surface of the elongate opening, making further work operations, for example drilling to provide lubrication passages transverse to the elongate opening, very difficult.
  • a method of casting comprising placing in a mould an elongate rigid member which is formed with an opening to facilitate the passage of gases during the casting process, introducing into the mould molten metal, permitting the metal to set to form a casting, removing the casting from the mould and removing the elongate rigid member from the casting, characterised in that prior to casting, the elongate rigid member is surrounded along at least part of its length, with an insulating material which is directly contacted and decomposed by the molten metal during casting.
  • an elongate opening is provided in the cast workpiece, during casting, and there is no need to subsequently drill or otherwise provide the opening. Because of the insulating material, the metal being cast is not brought immediately into contact with the elongate rigid member. Thus hardening of the resultant casting in the region surrounding the elongate member by a chilling effect as would otherwise occur, is alleviated. Furthermore, because the elongate rigid member is protected by the insulating material from the hot metal as it is cast, the elongate rigid member can be repeatedly re-used.
  • rigid member in a method in accordance with the present invention, we mean that the member is substantially self-supporting over its length so that no support intermediate its ends are required in the mould.
  • the insulating material can conveniently be a ceramic paper, i.e. a paper impregnated with ceramic particles such as that sold under the Trade Name "Triton Kaowool" and may be between 0.5 mm and 6 mm thick.
  • the paper and impregnated ceramic particles may be wrapped around the rigid member, or it is envisaged that the insulating material may be applied as a coating by dipping the elongate rigid member into a suspension of the paper and ceramic particles or otherwise.
  • the ceramic paper provides an insulating barrier between the hot metal as it is cast into the mould, and the relatively much cooler elongate rigid member.
  • any other suitable insulating material could be provided.
  • the elongate rigid member may comprise a solid rod, and the opening formed therein may comprise a longitudinally extending groove in the surface of the rod.
  • the elongate rigid member may comprise a tube or hollow rod, in which case the formed opening may comprise an aperture extending through the wall into the hollow thereof or more preferably a series of apertures.
  • the invention is particularly applicable to providing an axial opening for a camshaft, for passage of lubricant along the length of the camshaft in which case the mould may comprise a shell mould, the cam profiles on the camshaft being provided by shall moulding, although the method in accordance with the invention is also applicable to moulding by the green sand, gang method or any other moulding method as required.
  • radial passages which communicate with the axial elongate opening are also often required, and by providing the opening according to a method in accordance with the invention, the region of metal immediately surrounding the opening is not hardened by chilling due to the presence of the insulating material around the rod, and hence drilling radial passages in the cam shafts thus provided, is considerably facilitated.
  • the elongate rigid member need only be coated along part of its length with the insulating material, the remainder of the member being coated with moulding material.
  • an elongate rigid member 10 for use in a method according to the invention comprises a solid elongate rigid steel rod 11 having a central axis A. Extending axially in the surface of the rod 11 is an opening comprising a narrow groove 12 for a purpose hereinafter explained, which extends along the entire length of the rod 11.
  • Insulating material comprising ceramic paper sheet 13 is wrapped about the rod 11 for a major central part of its axial length, a small overlap 14 being provided so that the rod 11 is surrounded, ends 15 of the rod projecting from the ends of the sheet 13.
  • the paper sheet 13 is of the type sold under the Trade Name "Triton Kaowool" and comprises ceramic particles embedded in the paper during manufacture.
  • the paper sheet is between 0.5 mm and 6 mm thick, although best results have been obtained with paper sheet 0.5 mm thick.
  • the paper provides an insulating material to reduce the flow of heat to the rod 11 during casting, as hereinafter explained.
  • any other suitable insulating material could be used, although the ceramic paper described is preferred as this produces a longitudinal opening in the final casting with a smooth wall, obviating the need for further machining once the casting has solidified.
  • ceramic paper could be applied to the elongate rigid member 10 by dipping in a suspension of paper and ceramic particles and thereafter permitting the liquid in which the particles are suspended, to dry thus leaving the member 10 coated with the ceramic and paper particles.
  • Another insulating material may be provided as required, for example, by spraying, brushing, or otherwise.
  • FIG. 3 a moulding box 20 for casting a camshaft is shown, in which the elongate rigid member 10 of Figures 1 and 2 is received.
  • the moulding box 20 has a bottom part 21 with a bed of sand 22 therein, which provides one half of a two-part mould made by a conventional moulding technique as is well known in the art.
  • the moulding box 20 further comprises an upper part 24 in which the other half of the mould is provided by a further layer 26 of sand.
  • openings 27 and 28 are provided through the mould-half 26, to permit of the introduction of molten metal into a cavity 30 formed between the mould halves 22, 26.
  • Opposite engaging edges of the mould box 20 each have a U-shaped recess 32, 33, to receive the rod 11 which thus extends through the cavity 30 so that the rod 11 will extend through the resultant casting.
  • the sheet of paper and impregnated ceramic particles 13 covers the rod 11 over the entire length thereof between side walls 34, 35 of the moulding box 20 and thus no metal as it is cast, immediately directly contacts the rod 11, but rather contacts the insulating paper sheet 13.
  • chills 36, 37, 38 are also received in the cavity 30 moulded into the mould halves 22, 26 .
  • the chills 36, 37, 38 are located at the surfaces of where the cams of the camshaft will be formed, and thus chill the hot metal in these regions, resulting in a hardening of the casting in those regions. This is required to provide hard bearing surfaces for connecting rods of the engine in which the cam shaft will be assembled which, when the resultant camshaft is in use, bear on the cam surfaces.
  • Figure 3 is only a diagrammatic representation, and in practice, a camshaft may have more than three cams as shown, and other bearing surfaces for bearings in which the camshaft rotates about its axis A. Additional chills may be placed in the cavity 30 where required, for example around the bearing surfaces where provided, or indeed in any region where it is required to harden the surface of the metal.
  • hot molten metal which may be alloyed or unalloyd iron, or indeed any other suitable metal, is poured through the openings 27 and 28 into the cavity 30.
  • the metal is not chilled around the rod.
  • the ceramic paper 13 protects the rod 11 but is itself entirely consumed as the hot metal directly contacts the paper 13.
  • the short time delay from when the metal is cast to when the paper 13 is decomposed is adequate to allow the rod 11 to become heated sufficiently to ensure that even after the paper 13 is consumed, the cast metal is not significantly chilled round the rod 11 and hence the metal is not appreciably hardened in this region.
  • gases will be produced which require venting from the cavity 30. Gases may also be produced from any binder of the moulding material in the mould halves 22, 26. These gases may pass from the cavity 30 through auxiliary openings such as shown at 40 and via the groove 12 provided in the rod 11. If desired the rod 11 may have further axial grooves, similar to the groove 12, or may be at least partially hollow and have openings comprising apertures extending through the wall of rod 11 into the hollow, again to facilitate the venting of gases.
  • the mould box parts 21, 24 are separated and the casting shaken out of the mould. Thereafter, the rod 11 may be pulled axially from the casting to leave a clean elongate opening through the casting.
  • the rod 11 may be re-used in subsequent casting operations after a new sheet of paper 13, or other insulating material, has been applied.
  • the rod 11 when placed in the moulding box 20 is supported only at its ends, and is self-supporting otherwise.
  • the rod is sufficiently rigid, even if it is hollowed as mentioned above, to obviate the need for any supports intermediate its ends.
  • rod 11 has been described as being made of steel, any, other suitable rigid material which can withstand the hot casting temperatures could be used.
  • moulding materials other than sand could alternatively be used in the moulding process if required.
  • an alternative rigid member 10' comprises a thin walled tube 11' having a central hollow H, the tube 11' having an opening comprising a groove 12' similar to the groove 12 of the member 10 of Figures 1 to 3, the groove 12' being formed with radial apertures 50 along its length, into the hollow H.
  • any apertures provided into the hollow would be provided in the groove 12 rather than from the surface of the member.
  • An elongate rigid member 10" again comprises a thin walled tube 11" but without any surface groove. However a plurality of openings 12" are provided from the exterior of the tube 11" to an internal hollow H" thereof. It can be seen that end regions 15" of the tube 11" are each covered with a ceramic paper sheet insulating material 13a, 13b respectively, but a central region C of the tube 11" does not have a covering of insulating material, but rather, a layer of moulding material i.e. sand S is compacted onto the exterior surface of the tube 11".
  • the tube 11" is protected as hot metal is cast into a mould in which the tube 11" is received, like the mould 20 of Figure 3, by the insulating ceramic paper 13a, 13b.
  • the tube 11" is protected by the sand S.
  • the rigid member 10, 10', or 10" of all of the embodiments need not be of circular cross-section as described above where this shaped axial opening is not required, but the method is useful to produce an elongate opening of any desired cross-section in a casting, provided that a rigid member of complementary cross-section is used.
  • the opening thus provided is for the passage of lubricant along the camshaft. It is often required for radial passages to be provided from the opening to positions at or adjacent to the cam surfaces or bearing surfaces of the camshaft so as to pass lubricant to these positions.
  • the above described method facilitates the provision of these radial passages subsequent to casting because the metal of the casting in the region of the axial elongate opening produced is not hardened, due to the presence of the ceramic paper 13, 13a, 13b or other insulating means.
  • the method may be used to provide an elongate opening in other castings. If desired, more than a single longitudinal opening or other internal opening, in the casting may be provided, in which case more than one elongate rigid member each provided with an insulating means such as ceramic paper sheet, would need to be provided.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Valve-Gear Or Valve Arrangements (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Manufacture Of Alloys Or Alloy Compounds (AREA)
  • Casting Or Compression Moulding Of Plastics Or The Like (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)

Claims (10)

1. Procede de coulee comprenant l'étape consistant ä mettre en place dans un moule un element rigide allonge (10; 10'; 10") qui est muni d'une ouverture (12; 12'; 12") pour faciliter le passage des gaz pendant le procede de coulee, a introduire du metal fondu dans le moule, ä permettre la prise du metal pour former un corps moule, ä enlever le corps moule du moule et a enlever I'element rigide allonge (10; 10'; 10") du corps moule, caracterise en ce que préalablement ä la coulee, I'element rigide allonge (10; 10'; 10") est entoure sur au moins une partie de sa longueur, d'un materiau isolant (13; 13a; 13b) qui est directement mis en contact avec le metal en fusion lors de la coulee et qui se decompose sous l'action dudit métal.
2. Procede selon la revendication 1, caracterise en ce que le materiau isolant (13; 13a; 13b) est un papier impregne de particules ceramiques.
3. Procede selon la revendication 1, caracterise en ce que le papier (13; 13a; 13b) presente une epaisseur situee entre 0,5 mm et 0,6 mm.
4. Procede selon la revendication 2 ou la revendication 3, caracterise en ce que le papier et les particules ceramiques impregnees (13; 13a; 13b) sont enveloppees autour de l'élément rigide allonge (10; 10'; 10").
5. Procede selon l'une quelconque des revendications precedentes, caracterise en ce que I'element rigide allonge (10) est une tige en metal plein (11) et l'ouverture (12) formee dans celle-ci comprend une rainure s'etendant longitudinalement dans la surface de la tige (11).
6. Procede selon l'une quelconque des revendications 1 ä 4, caracterise en ce que I'element rigide allongee (10'; 10") est creux et l'ouverture (12'; 12") comprend un orifice s'ouvrant, a travers la paroi dudit element rigide, sur sa partie creuse.
7. Procede selon la revendication 1, caracterise en ce que I'element rigide allonge est un tube ä paroi mince (10'; 10").
8. Procede selon l'une quelconque des revendications precedentes, caracterise en ce que le materiau de moulage du moule est forme de telle maniere que la piece coulee produite est un arbre ä cames (0).
9. Procede selon la revendication 8, caracterise en ce que le moule comprend un moule carapace, les profiles de cames sur l'arbre ä cames etant realises par moulage en carapace.
10. Procede selon l'une quelconque des revendications precedentes, caracterise en ce que l'élé- ment rigide allonge (10") est revetu du materiau de moulage (S) sur une partie de sa longueur non entouree ou revetue du materiau isolant decomposable.
EP85100891A 1984-02-08 1985-01-29 Verbesserungen in Bezug auf das Giessen Expired EP0154787B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT85100891T ATE33217T1 (de) 1984-02-08 1985-01-29 Verbesserungen in bezug auf das giessen.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8403355 1984-02-08
GB848403355A GB8403355D0 (en) 1984-02-08 1984-02-08 Castings

Publications (2)

Publication Number Publication Date
EP0154787A1 EP0154787A1 (de) 1985-09-18
EP0154787B1 true EP0154787B1 (de) 1988-03-30

Family

ID=10556296

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85100891A Expired EP0154787B1 (de) 1984-02-08 1985-01-29 Verbesserungen in Bezug auf das Giessen

Country Status (4)

Country Link
EP (1) EP0154787B1 (de)
AT (1) ATE33217T1 (de)
DE (1) DE3561989D1 (de)
GB (1) GB8403355D0 (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1990006197A1 (de) * 1988-12-06 1990-06-14 Von Roll Ag Verfahren und giessform zum giessen von wellen
US5201357A (en) * 1992-01-16 1993-04-13 Cmi International, Inc. Method for forming cored passageways within cast metal articles
EP0839990A1 (de) 1996-11-01 1998-05-06 Roland Klaar Gebaute Nockenwelle
AT410910B (de) * 2001-11-14 2003-08-25 Styrokeram Ges Fuer Feuerfeste Oberzapfenisolierung für walzenguss

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3532196A1 (de) * 1985-09-10 1987-04-16 Wizemann Gmbh U Co J Nockenwelle und vorrichtung zu ihrer herstellung
DE4431713C2 (de) * 1994-09-06 2001-03-15 Audi Ag Vorrichtung zum Herstellen von Gußstücken
CN110479964A (zh) * 2019-09-05 2019-11-22 中船海洋动力部件有限公司 一种船用柴油机机体铸件的大型砂芯制作和准备方法
CN112846091A (zh) * 2019-11-27 2021-05-28 尼玛克股份有限公司 利用型芯的金属铸造

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB386302A (en) * 1930-04-11 1933-01-12 Fermiere Des Fonderies Acierie Improvements in or relating to foundry moulding
GB663781A (en) * 1948-12-01 1951-12-27 Cecil Dunkin Improvements relating to foundry practice
GB700777A (en) * 1951-04-05 1953-12-09 Grahamston Iron Company Ltd Improvements relating to core bars for use in moulding metal pipes
US2897556A (en) * 1957-09-04 1959-08-04 Sperry Rand Corp Method of coring holes in castings

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1990006197A1 (de) * 1988-12-06 1990-06-14 Von Roll Ag Verfahren und giessform zum giessen von wellen
GR890100808A (en) * 1988-12-06 1991-03-15 Von Roll Ag Method and moulding for axles casting
US5201357A (en) * 1992-01-16 1993-04-13 Cmi International, Inc. Method for forming cored passageways within cast metal articles
EP0839990A1 (de) 1996-11-01 1998-05-06 Roland Klaar Gebaute Nockenwelle
DE19645112A1 (de) * 1996-11-01 1998-05-14 Roland Klaar Gebaute Nockenwelle
US5992265A (en) * 1996-11-01 1999-11-30 Eisengiesserei Monforts Gmbh & Co. Built-up camshaft
AT410910B (de) * 2001-11-14 2003-08-25 Styrokeram Ges Fuer Feuerfeste Oberzapfenisolierung für walzenguss

Also Published As

Publication number Publication date
ATE33217T1 (de) 1988-04-15
DE3561989D1 (en) 1988-05-05
GB8403355D0 (en) 1984-03-14
EP0154787A1 (de) 1985-09-18

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