Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D15/00—Casting using a mould or core of which a part significant to the process is of high thermal conductivity, e.g. chill casting; Moulds or accessories specially adapted therefor
  • B22D15/02—Casting using a mould or core of which a part significant to the process is of high thermal conductivity, e.g. chill casting; Moulds or accessories specially adapted therefor of cylinders, pistons, bearing shells or like thin-walled objects
• • 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
• • 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
• • 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
  • B22C9/103—Multipart cores

Definitions

• the invention relates to a casting mold for casting a casting, which is composed of moldings and casting cores made of molding sand and has at least one casting core for imaging a space in the casting.
• Molds of this type are used in particular for casting engine blocks for internal combustion engines.
• the casting core in the engine block casting forms the respective combustion chamber, while the other molded part depicts the top surface of the engine block on which the cylinder head of the respective internal combustion engine is placed and fastened, if necessary, during assembly as an attachment.
• the cylinder cavities of the engine block molded by molds inserted into the sand mold, which consist of a brass material.
• the aluminum solidifies faster than on the surface of the sand mold due to the higher thermal conductivity of the metal of the mold. This creates there up to a sufficient Depth a structure that has a higher resistance to the stresses occurring in practical use on the running surfaces of the cylinder loads.
• the object of the invention was to provide a casting mold, which makes it possible in a simple manner to produce castings, in which at least one locally narrowly defined section is formed with a structure that is different from the rest of the casting.
• an advantageous use of such a mold should be specified.
• the casting core which depicts the respective space in the casting is divided into at least two sections.
• the first section is formed by a chill, while the other section consists of sand usually used in the sand casting molding sand.
• Such molding sands are known to be mixtures of a generally free-flowing molding base material and a binder. This molding sand mixture is formed in a core molding tool to the respective molding or casting core and solidified by a suitable mechanical, chemical and / or thermal treatment so that the obtained part or core has a sufficient dimensional stability for the casting process.
• the cooling mold used according to the invention as part of the casting core forming the space has according to the invention a much higher thermal conductivity than the molding sand from which the remainder of the casting core is made. Accordingly, in the region of the casting mold in which the melt poured into the casting mold comes into contact with the cooling mold, a locally limited accelerated cooling occurs.
• the speed with which the locally limited cooling takes place and the amount of heat removed from the casting metal can be influenced directly. In this case, the expansion of the region over which the purposefully accelerated removal of heat should take place can be adjusted in a simple manner by the shape of the mold by the shaping of the casting mold.
• the casting core representing the respective cylinder space is provided with an annular cooling mold whose height taking into account the thermal migration of the selectively cooled partial length of the cylinder chamber corresponds.
• the casting material comes into direct contact with the mold, so that a particularly rapid heat removal impeded by any intermediate layer acting as an insulator occurs.
• the invention thus enables the cost-effective production of castings, in which locally closely bounded zones with a cast structure produced by accelerated cooling are present in the region of a space to be formed in each case in the castings.
• a particularly advantageous in terms of mass production variant of the invention provides that the chill is made of cast iron. Chill molds made of cast iron can be produced inexpensively and have one in view of this desired processing objective favorable thermal conductivity.
• a casting mold according to the invention is particularly suitable for the production of such castings in which, in the region of a transition between the space to be produced in the casting and a mounting surface, the structure which becomes fair during operation is to be produced.
• An embodiment of the invention which is important for practical use therefore provides that at least one of the mold parts of a casting mold according to the invention forms a mounting surface on which an attachment can be mounted on the casting after its solidification and the mold core adjoins this molded part, in particular with the cooling mold ,
• the thermal conductivity of the cooling mold should also be many times higher than the thermal conductivity of the molded part imaging the mounting surface.
• the correct position assignment of the chill mold and the remaining portion of the space in the casting casting core can be ensured with ease of use that are formed on the chill and the remaining portion of the casting mold form elements over which the chill mold and the remaining portion of the mold core with each other are connected.
• the cooling mold is used in such a way that it cools a zone of the casting to be produced, which surface merges into the mounting surface, then it is favorable if at least one molding element is formed on the cooling mold positively engages in a correspondingly shaped recess of the molded part.
• This form element is preferably formed as a projection engaging in the molding.
• the cooling mold which engages in the respective molded part projects beyond the mounting surface to be produced on the casting, so that the formation of burrs or comparable shape defects in the area of the opening of the respective cylinder space is reliably prevented.
• the inner surface of the projection relative to the longitudinal axis of the chill is tapered so that widens the diameter of the opening of the casting core in the direction of the molding, while the demolding of the chill mold from the finished casting can be additionally facilitated.
• the casting core with the cooling mold is held by a punch extending into the casting core.
• This stamp can be used for a precisely positioned holding the casting core.
• such a stamp when it is coupled with a corresponding adjusting device, allows automatic assembly of the casting core itself.
• liners are, for example, made of cast iron prefabricated tubular components whose inside diameter corresponds to the inside diameter of the engine block to be imaged Cylinder chamber corresponds and whose inner surfaces in the finished engine block form the running surfaces along which moves during operation of the piston of the internal combustion engine. Even with a casting mold according to the invention, liners can be poured into the casting to be produced while simultaneously exploiting the advantages of the invention if the casting core carries on its outer surface a liner to be cast into the casting.
• the single figure shows schematically a mold G for casting an engine block for a in-line four-cylinder internal combustion engine.
• the casting mold 1 is composed of various molded parts 1, 2, 3, 3 and casting cores 4, 5, 6, 7, each made of molding sand, which are each formed from a section 8 prefabricated from molding sand and a cooling mold 9.
• shaped part 1 shown in the figure above is a so-called “sole core” on the engine block to be cast
• the mounting surface 10 also called “top deck surface”
• images in the course of assembly of the internal combustion engine
• cylinder head is attached.
• the opposite to the molded part 1 arranged molding 2 represents the so-called “crank chamber core”, which images the crankcase on the engine block to be cast.
• the casting cores 4,5,6,7 are each held by a stamp 11,12,13,14.
• the punches 11-14 are coupled to an adjusting device (not shown here), which move them from an assembly position in which the casting cores 4, 5, 6, 7, 7 are mounted on them into the position shown in the figure.
• the front in the respective casting core 4-7 projecting portion 15 of the punches 11-14 is formed over the entire height of the cores 4-7 tapered in the direction of the free punch end to the punch 11-14 after completion of the casting process unhindered from the Casting cores 4-7 to be able to pull.
• the molded sand section 8 of the casting cores 4-7 has a cup-like shape, wherein the surrounding of its interior is adapted to the shape of the front portion 15 of the punches 11-14, that the relevant section 15 is positively seated in the interior.
• projection 16 is formed, which engages in a correspondingly shaped recess 17 of the molding 2 and is also held positively held therein.
• the cooling molds 9 of the casting cores 4-7 are positively coupled to the section 8 of the respective casting core 4-7 made of molding sand.
• the cooling molds 9 themselves have an annular shape. The interior surrounded by them is adapted to the shape of the front, each associated with them portion 15 of the punches 11-14 has, so that the cooling molds 9 are also held positively and substantially free of play on their respective associated punch 11-14 ,
• a circumferential projection 20 is likewise integrally formed on the cooling molds 9, the outer circumferential surface of which, as in the case of the projection 19, merges without failure into the peripheral surface 21 of the main section of the respective cooling mold 9.
• the cooling molds 9 in this case have a tapering in the direction of the free end of its projection 19, slightly conical shape.
• the common circumferential surface 21 of the cooling molds 9 is inclined at an angle of at least 2 ° with respect to its longitudinal axis L coinciding with the longitudinal axis of the punches 11-14.
• the inner surface of the cooling molds 9 is inclined.
• the conical outer shape of the chill molds 9 facilitates the demoulding of the chill molds 9 from a liner 22, which is held in a form-fitting manner by the respective casting core 4-7 and, after completion of the solidification, remains in the engine block to be cast in the casting mold G.
• the liners 22 surround the cylinder spaces imaged by the casting cores 4-7 in the engine block.
• the height of the projections 20 of the cooling molds 9 is dimensioned so that they are in the finished mold G in the casting cores 4-7 and molded parts 1-3 respectively beyond the mounting surface 10 in each case one correspondingly shaped recess 23 of the molded part 1 engage. In this way, a degree of formation in the region of the opening of the cylinder chambers of the engine block to be cast is reliably prevented.
• feeders and filling channels are formed in a manner known per se, via which aluminum melt poured into the casting mold G flows into the mold cavity 24 surrounded by the casting mold G.
• the thereby reaching into the cooling molds 9 adjacent areas 25 of the mold cavity 24 melt is extracted over the liner 22 and the respective cooling mold 9 accelerated heat so that it solidifies faster than the present in the other zones of the mold cavity 24 melt.
• a directional, finer-grained structure arises, so that the portion of the engine block which is particularly loaded in this area and which is adjacent to the mounting surface 10 reliably withstands the thermal and mechanical loads occurring in practical operation.

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Publications (1)

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• 2006
  • 2006-11-10 DE DE102006053404A patent/DE102006053404A1/de not_active Withdrawn
• 2007
  • 2007-11-09 JP JP2009535740A patent/JP2010509070A/ja active Pending
  • 2007-11-09 PL PL07857208T patent/PL2091678T3/pl unknown
  • 2007-11-09 KR KR1020097009573A patent/KR20090077949A/ko not_active Application Discontinuation
  • 2007-11-09 DE DE202007018797U patent/DE202007018797U1/de not_active Expired - Lifetime
  • 2007-11-09 MX MX2009004733A patent/MX2009004733A/es not_active Application Discontinuation
  • 2007-11-09 CN CN2007800418754A patent/CN101547760B/zh active Active
  • 2007-11-09 EP EP07857208.8A patent/EP2091678B1/de active Active
  • 2007-11-09 WO PCT/EP2007/062131 patent/WO2008055973A1/de active Application Filing
  • 2007-11-09 RU RU2009122220/02A patent/RU2432223C2/ru active
  • 2007-11-09 US US12/513,757 patent/US20100139884A1/en not_active Abandoned

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