DE102005019961A1 - Production of cast parts in compound gas used in automobile production, e.g. for production of cylinder crankcases, comprises removal core medium in second casting process into cooling vessel in pressure casting machine - Google Patents

Abstract

The production of cast parts in a compound gas (sic), especially an automobile cylinder crankcase where an insert obtained in a first casting process with an open hollow space is transferred (sic) to a pressure casting mold for forming the cast part and for acceptance of the casting pressure during a second casting process the hollow space is filled with a core medium. The core medium is later transferred during the second casting process during cooling/chilling of the cast part (10) into a cooling vessel in a pressure casting machine.

Description

The The invention relates to a method for producing a casting Compound casting, in particular a cylinder crankcase for an internal combustion engine, wherein a manufactured by a first casting process, with at least one at least partially open cavity provided Insert in a casting mold forming the casting in one second casting process is poured around and wherein for receiving the casting pressure during the second casting process the at least one cavity is filled with a core medium.

One Particularly preferred application of the invention results in recast a closed-deck cylinder inlay by die casting. A lighter one (eg magnesium) die-cast engine block has a cylinder insert in closed-deck construction with an integrated cooling water jacket from a hypereutectic Aluminum alloy for high rigidity, good corrosion and tread properties.

preferred Features of die casting are: low cycle time due to fast Solidification, very fast mold filling with high pressures and Flow rates, high contour accuracy and dimensional accuracy as well as a cost-effective Production method. Preferred properties of a closed-deck cylinder inserter are: high overall strength, support the liner in the area of the cylinder deck, low cylinder distortion and the possible use a hypereutectic Aluminum alloy. However, the problem proves to be the support of the water jacket when pouring in die casting.

Of the Water jacket space of the insert must not during casting by the high pressure of the hot Melt compressed become. Because of the high pressures encountered during die casting (several 100 bar) and because of the high flow rates of the melt (filling time approx. 40 msec.) activities so that the water jacket room does not collapse and possibly filled with melt becomes. Depending on brittleness of the cylinder liner material may be deformed or too to breaks in the enclosure walls come.

It It has been shown that it requires a full-volume filling to one by Druckießverfahren umgießenden Sufficiently support the cavity. A full-volume support can be done by a medium, which in particular incompresibel, temperature resistant is and easy filling and releasability allows. These properties are met z. B. molding sand, which compacted by means of a core shooter in a Cavity be filled can. Here, however, the problem arises that the sand by no means into the mold of the die casting machine advised may. Sand with binder is used to solve this problem to encounter, so the demolding difficult, since z. B. when casting no subsequent magnesium Glow to Solve the Binders may be used.

With regard to the relevant patent literature is first on the EP 1 440 749 A1 to refer to a method for producing a cylinder block in composite casting for a liquid-cooled internal combustion engine. In this case, a series of integrally connected cylinder tubes made of an aluminum alloy cast as a cast insert in a cylinder block housing forming mold with a magnesium alloy. The cylinder tubes are placed in an end portion of an integrally formed, the cylinder tubes for a cylinder head side open coolant space spaced circumferential wall with the housing in a Umgussverbindung. The enveloping wall is deformed outward by a predetermined amount from the cylinder tubes via pressure cores disposed in the die.

Especially in a closed-deck construction is with such pressure cores however, no full-volume support possible.

The DE 41 02 358 C2 describes a method for producing a molded part, in particular a cylinder head for an internal combustion engine, wherein the molded part is produced by a die casting method, a hollow body inserted into a die and filled with a core medium full volume before die casting, wherein the core medium primarily for the transmission of the specific pressing pressure serves on the inner contour of the hollow body and at least one end wall is formed by the core medium at least one opening of the hollow body, wherein after the die casting, the core medium is removed and the hollow body remains in the molding. The full volume filling the cavity core medium consists essentially of sand, optionally with binding portion. In addition, the core medium, at least on the open sides of the hollow body to a seal against the ingress of melt. This seal may be formed as a coating, coating, glaze or membrane. After the casting process, the core medium can be shaken out or melted out.

The invention is based on the object that generic method for producing egg To further optimize castings in composite casting and in particular to ensure fast and thorough removal of the core medium after the casting process.

These Task is solved by the patent claim 1. Advantageous embodiments and further developments of the invention are claimed in the Unteransprü Chen. In the figures, the invention is shown by way of example and below explained accordingly. Show it:

1 schematized and shown in perspective, a plant for the production of a casting according to the invention and

2 a section of the casting with a filled with sand and binder full volume cavity in a sectional view.

A die casting machine 1 has the known structure, so that it need not be discussed in detail in detail. On a foundation 2 there is a die casting mold 3 , their individual components via linear motion units 4 . 5 . 6 . 7 . 8th and a hinge mechanism 11 for opening or closing the die 3 to be moved.

The die casting machine 1 assigned and immediately adjacent to it is a cooling pool 9 , which also has a known structure. This can be one of the die casting machine 1 removed casting 10 thermally treated, for. B. be deterred.

For the purpose of transporting the casting 10 from the die casting machine 1 to the cooling pool 9 is an arranged between two and on a foundation 12 mounted articulated arm robot 13 intended.

2 shows a section of a casting 10 , which may be based on the initially discussed prior art, a cylinder block of a liquid-cooled internal combustion engine, consisting of a housing 14 and a number of cylinder tubes arranged one behind the other 15 as an insert, wherein these in an upper end portion via an integrally formed envelope wall 17 , in a cylinder head side at least partially open coolant chamber 16 lead. The coolant space 16 is full volume for taking up the casting pressure with a sand 18 (For example, quartz or zircon sand) filled, with the sand in the upper end of the cylinder head end 18 additionally with an inorganic, water-soluble binder 19 (Eg Ba sis magnesium sulfate) is mixed. It would also be conceivable, the sand 18 in total with binder 19 to mix.

• – Gießen der Zylinderrohre 15, z. B. im Niederdruck-Kokillenguss, mit Cold- box Kern als Wassermantelkern für closed-deck-Ausführung,
• – mechanisches Entsanden der Zylinderrohre 15 durch Rütteln,
• – Wärmebehandlung der Zylinderrohre 15 und thermische Restentsandung,
• – Vorbearbeitung der Zylinderrohre 15,
• – komplettes Auffüllen des Kühlmittelraumes 16 mit anorganisch gebundenem Sand (Sand 18, anorganischer Binder 19) und
• – Umgießen der Zylinderrohre 15 im Druckgussverfahren.

The pre-Entsandungsvorgang steps for the production of the casting 10 are the following:

• - casting the cylinder tubes 15 , z. Eg in low-pressure chill casting, with cold box core as water jacket core for closed-deck design,
• - mechanical sanding of the cylinder tubes 15 by shaking,
• - Heat treatment of the cylinder tubes 15 and thermal residue disposal,
• - Pre-processing of the cylinder tubes 15 .
• - complete filling of the coolant chamber 16 with inorganically bound sand (sand 18 , inorganic binder 19 ) and
• - casting around the cylinder tubes 15 in die casting.

The desanding process proceeds as follows:
After mold filling, the articulated arm robot detects 13 for casting removal by means of a suitable tool (eg hydraulic tongs) the casting 10 on the press residue and removes it from the die casting machine 1 or from the opened die casting mold 3 , After placing in the cooling basin 9 in the usual way, immersion in the quenching fluid present there, combined with a pivoting back and forth of the casting 10 through the articulated arm robot 13 , Due to the water solubility of the binder 19 the sand binder mixture is dissolved and the coolant in the space 16 located sand 18 or binder 19 trickles out. In order to optimize this process would be conceivable, about in the cooling pool 9 located nozzles certain parts of the casting 10 purposely with high pressure to rinse.

In the cooling basin 9 accumulates over time by a mixture of water, sand 18 and binder 19 at. This mixture can be drained or sucked off. The sand 18 can be filtered off and reused after drying. The remaining water-binder mixture can be separated by appropriate procedural measures.

The integration of desanding directly into the die casting process primarily brings about a simplification of the process, since no additional work step becomes necessary. Thus, there are no additional costs for the Entsandungsvorgang. Also the preparation and reuse of sand 18 and inorganic binder 19 leads to cost savings.

Claims (4)

Method for producing a cast part in composite casting, in particular a cylinder crank housing for an internal combustion engine, wherein a produced by a first casting process, providing at least one open cavity insert in a casting die forming the casting is poured in a casting process and wherein the at least one cavity is filled with a core medium for receiving the casting pressure during the second casting process , characterized in that the subsequent removal of the core medium ( 18 ) in the course of the second casting process during the cooling / quenching process of the casting associated with the casting process ( 10 ) in one of the die casting machine ( 1 ) associated cooling pool ( 9 ) he follows. Method according to claim 1, characterized in that the removal of the core medium ( 18 ) by pivoting the casting ( 10 ) and assisted by additional spraying with cooling fluid. Method according to claim 1, characterized in that the cavity ( 16 ) full-volume with a sand-binder mixture ( 18 . 19 ) is filled. Method according to claim 1, characterized in that the cavity ( 16 ) full volume with sand ( 18 ) and this only in the region of the cavity opening with an inorganic, water-soluble binder ( 19 ) is mixed.