DE102019102916A1 - Casting mold and method for casting a component - Google Patents

Abstract

Casting mold comprising a plurality of mold elements which are designed to form a cavity for a component, wherein at least one first mold element rests against a second mold element by means of an intermediate element, and wherein the intermediate element is designed such that when the cavity is filled with Melt dissolves.

Description

The present invention relates to a casting mold, in particular a casting mold for gravity casting, and a method for casting a component.

In the foundry, casting molds or casting molds are or form hollow bodies into which the liquid melt is poured. So-called cores are provided for forming hollow bodies in the later component. Due to the buoyancy prevailing during casting, the cores may lose their original position during casting. In order to prevent a relative movement of, for example, two core elements to one another, the DE 10 2012 015 328 A1 a process in which the core elements are supported on the outside. The disadvantage here is that a later closing of the openings or recesses that are created as a result is necessary, which leads to additional expenditure and additional costs. As a remedy, the DE 10 2012 015 328 A1 therefore in front of a casting core, which can be arranged or arranged in a casting mold of the casting device, with at least one first core element, with at least one second core element lying at least in sections on the first core element, and with at least one fixing device for at least limiting a relative movement of the first core element to the second core element in at least one relative movement direction, the fixing device comprising at least one first fixing means arranged on the first core element and at least one second fixing means arranged on the second core element. However, this complicates the shape of the cores. In addition, such a fixing device creates a connection between the cores, which may also have to be closed again in the course of reworking. This is the case, for example, if one core is an oil chamber core of a cylinder head and the other core is a water jacket core of the cylinder head.

It is therefore an object of the present invention to provide a casting mold and a method for casting a component, which eliminate the aforementioned disadvantages and optimize the known components and methods.

This object is achieved by a casting mold according to claim 1 and by a method according to claim 10. Further advantages and features emerge from the subclaims and the description and the attached figures.

According to the invention, a casting mold comprises a multiplicity of shaped elements which are designed to form a cavity for a component, at least one first shaped element being in contact with or arranged on a second shaped element by means of an intermediate element, and the intermediate element being designed such that it Filling the cavity with melt dissolves. “Dissolving” means, among other things, burning, (decomposing) or the like. In particular, the “dissolving” can also mean the change in the physical state, for example from solid to liquid and / or gaseous. The intermediate element expediently does not represent a “core” which leaves a cavity in the later casting. The great advantage of the intermediate element is that it is designed to perform a temporary or temporary holding and / or supporting function, as a result of which at least the first shaped element is fixed in position. Correspondingly, a relative displacement of the two shaped elements from one another during the casting process can be prevented. Nevertheless, no undesired connecting channel or cavity remains between the two shaped elements through the intermediate element. The intermediate element can also be referred to as a lost foam intermediate element, which comprises a holding, holding-down and / or supporting function.

According to one embodiment, the intermediate element is designed and / or positioned to hold or support the first shaped element against displacement during casting by means of the second shaped element. Advantageously, a flow of force between the first shaped element and the second shaped element is made possible, so to speak, via the intermediate element, as a result of which the first shaped element can be held in an intended position. It should be mentioned at this point that the materials of the shaped elements can be the same or different. In particular, the second molded element can be a permanent molded element and the first molded element can be a lost molded element, according to one embodiment a lost core, in particular a sand core. The casting mold as such can be designed as a permanent shape or as a lost shape. In the aforementioned variant, it is assumed that the second molded element itself is fixed in its position, so that the first molded element can be supported by the intermediate element. The second shaped element can also be a section of a mold, while the first shaped element is a sand core. The second shaped element can in turn be fixed in position via one or more intermediate elements via a third shaped element etc. In particular, the second shaped element can also be a core.

According to one embodiment, the second shaped element is positioned such that it supports the first shaped element against the buoyancy acting during casting via the intermediate element. The second shaped element is expediently above or arranged above or at least in regions above or above the first molded element (based on the direction of gravity), whereby in combination with the intermediate element, buoyancy of the first molded element can be supported.

The forces acting during casting act in all spatial directions, so that the position and position of the intermediate element is not limited to merely supporting an upward lift. In particular, the intermediate element is provided and advantageously positioned such that it generates a supporting effect in any spatial direction. A plurality of intermediate elements are expediently also arranged between two shaped elements.

According to a preferred embodiment, the intermediate element is formed from a plastic, in particular from polystyrene. It has been shown that this material harmonises well with the melt. The melt is in particular a metallic melt, for example a steel material or a steel alloy or an aluminum material or an aluminum alloy.

The intermediate element is preferably formed from a porous material. The material of the intermediate element is advantageously completely or at least partially permeable to air and / or gas. This advantageously enables mold or core degassing, at least up to a certain point in time.

According to one embodiment, the intermediate element has a circumferential size or coating, which is designed in particular to influence a temperature resistance of the intermediate element. In particular, a temperature from which the intermediate element dissolves, in particular a melting temperature, can be set, in particular increased, in this way. According to one embodiment, the coating is a metallic coating, the material corresponding to the melt. Depending on the material, the thickness of the coating is a few tenths of a millimeter. Alternatively, a ceramic-based coating can also be used. The actual design depends in particular on the material of the melt and may have to be determined by experiment.

According to one embodiment, the intermediate element comprises at least one channel, which is designed for degassing the casting mold. In particular, a corresponding channel is advantageously provided in at least one of the shaped elements on which the intermediate element rests, in order to allow degassing to the outside.

According to one embodiment, the intermediate element has two contact surfaces, which are each provided for contacting the first molded element and the second molded element.

In particular, a form-fitting system is provided between the respective shaped elements and the intermediate element. According to one embodiment, the at least one contact surface also forms an undercut. As a result, not only compressive forces but also tensile forces can be transmitted.

According to a preferred embodiment, the intermediate element has a structurally simple shape, for example a cylindrical or conical shape.

According to a preferred embodiment, the first molding element and the second molding element are sand cores, which are designed to form cavities in the component.

According to a preferred embodiment, the first shaped element is in particular a water jacket core of a cylinder head of an internal combustion engine and the second shaped element is an oil chamber core of the cylinder head.

As already mentioned, several intermediate elements can be arranged between the shaped elements. It is also possible for several shaped elements to be supported on a shaped element via corresponding intermediate elements. In principle, a large number of intermediate elements can be arranged or provided, since these are no longer present in the later casting anyway.

At this point it should be mentioned that the intermediate elements, or the one intermediate element, are expediently positioned such that the shape retention or core retention is possible at least up to a certain point in time. This is ensured, for example, if the or at least one intermediate element is arranged in an area of the cavity which is filled with the melt relatively late. In other words, the cavity is expediently already filled with melt to such an extent or solidified or at least pre-solidified in certain sections that the holding and supporting function etc. of the intermediate element is no longer required.

• - Bereitstellen einer Vielzahl von Formelementen zum Formen einer Kavität zum Gießen eines Bauteils;
• - Anordnen zumindest eines Zwischenelements, insbesondere zwischen den Formelementen oder zwischen einem ersten und einem zweiten Formelement, in der Kavität zum Fixieren, Positionieren und/oder Halten zumindest eines der Formelemente, z. B. des ersten Formelements, in einer vorgesehenen Position und Verwenden eines Werkstoffs für das Zwischenelement, welcher sich beim Gießen auflöst;
• - Abgießen des Bauteils.

The invention also relates to a method for casting a component, in particular in gravity casting, comprising the steps:

• - Providing a plurality of mold elements for molding a cavity for casting a component;
• - Arranging at least one intermediate element, in particular between the shaped elements or between a first and a second shaped element, in the cavity for fixing, positioning and / or holding at least one of the shaped elements, for. B. the first molded element, in an intended position and using a material for the intermediate element, which dissolves during casting;
• - Casting the component.

The casting can be a casting with a lost shape. Alternatively, it can be a casting with a permanent mold, for example a permanent mold casting process. In particular, the aforementioned shaped elements can be cores, in particular sand cores. Such intermediate elements can also be used in die casting, if necessary. A preferred application is gravity casting.

• - Anordnen eines ersten Fluidraumkerns an einem zweiten Fluidraumkern über zumindest ein Zwischenelement.

According to one embodiment, the method comprises the step:

• - Arranging a first fluid space core on a second fluid space core via at least one intermediate element.

A fluid space core is in particular a core or core element which is provided for forming a cavity for a fluid, such as water or oil. A fluid space core can be, for example, a water jacket core or an oil space core of a cylinder head of an internal combustion engine. Such fluid space cores can, however, also be used in the area of other components, for example in housings for electrical machines, etc.

The proposed casting mold and the method enable simplification of raw part machining and finished part machining. Core hold-down openings between two cores, such as the water jacket core and the oil chamber core of a cylinder head, no longer have to be closed in a complex manner, for example by means of closure elements such as beta plugs. The dissolving of the intermediate element forms a tightly closed cast wall at the point at which the intermediate element was positioned. It is irrelevant whether the intermediate element is arranged in an inner region of the component or towards the outside.

The advantages and features mentioned in connection with the casting mold apply analogously and correspondingly to the method and vice versa. Further advantages and features emerge from the following description of an embodiment of a casting mold with reference to the attached figures.

• 1: eine schematische Ansicht einer Gießform zum Darstellen einer Schnittebene;
• 2: einen Schnitt durch eine Gießform, wie in der 1 skizziert, mit einer Kernanordnung gemäß dem Stand der Technik;
• 3: einen Schnitt durch eine Gießform, wie in der 1 skizziert, mit zwei Kernen, zueinander positioniert über ein Zwischenelement;
• 4: eine Detailansicht von zwei Formelementen, verbunden oder kontaktiert über ein Zwischenelement.
• 1 zeigt in einer schematischen perspektivischen Ansicht eine Gießform 1, welche im Wesentlichen vier außenseitige Formelemente 10 umfasst. Mit dem Bezugszeichen E ist eine Schnittebene skizziert. Zur weiteren Erklärung sei nun auf die 2 und 3 verwiesen.
• 2 zeigt einen Schnitt durch eine Gießform 1, wie in der 1 skizziert, wobei vier Formelemente 10 zu erkennen sind. Weiter ist zu erkennen, dass innerhalb der Gießform 1 noch zwei weitere Formelemente, insbesondere ein erstes Formelement 11 und ein zweites Formelement 12 angeordnet sind. Insbesondere handelt es sich dabei um Kerne, beispielsweise aus einem Formstoff wie Sand. Diese sind derart geformt, dass sie aneinander anliegen. Insbesondere verhindert das zweite Formelement 12, dass sich das erste Formelement 11 aufgrund des beim Gießen wirkenden Auftriebs nach oben verlagert. Die Formelemente 10, 11 und 12 formen eine Kavität 2. In der rechten Bildhälfte ist das fertig gegossene Bauteil 3 schraffiert dargestellt. Zu erkennen ist, dass die durch die Formelemente 11 und 12 gebildeten Hohlräume verbunden sind. Dies ist ggf. nicht gewollt. Eine derartige Verbindung oder ein derartiger Kanal muss in irgendeiner Art und Weise verschlossen werden, beispielsweise von außen durch das Einbringen eines Verschlusselements, wie eines Betaplugs.
• 3 zeigt im Wesentlichen die aus der 2 bekannte Anordnung, sodass auf die Erklärung der technischen Merkmale nicht weiter eingegangen wird. Entscheidend ist, dass das erste Formelement 11 und das zweite Formelement 12 nun über ein Zwischenelement 30 kontaktiert bzw. verbunden sind. Insbesondere kann sich das erste Formelement 11 gegenüber dem zweiten Formelement 12 mittels des Zwischenelements 30 abstützen. Das zweite Formelement 12 ist zweckmäßigerweise entsprechend lagefixiert, wobei dies in dieser Schnittansicht nicht zu erkennen ist. In der rechten Bildhälfte ist ein entsprechend gegossenes Bauteil 3 dargestellt, wobei zu sehen ist, dass die durch das erste Formelement 11 und das zweite Formelement 12 geformten Hohlräume nicht miteinander verbunden sind, da das Zwischenelement 30 in der Schmelze aufgelöst wurde. Formt das zweite Formelement 12 beispielsweise einen Ölraumkern eines Zylinderkopfs und das erste Formelement 11 einen Wassermantelkern, so ist dies auch nicht erwünscht. Gegenüber dem Bauteil, wie es in der 2 skizziert ist, ist vorteilhafterweise keine Nacharbeit erforderlich.

Show it:

• 1 : a schematic view of a mold for showing a sectional plane;
• 2nd : a cut through a mold, as in the 1 outlined, with a core arrangement according to the prior art;
• 3rd : a cut through a mold, as in the 1 sketched, with two cores, positioned to each other via an intermediate element;
• 4th : a detailed view of two form elements, connected or contacted via an intermediate element.
• 1 shows a mold in a schematic perspective view 1 , which essentially have four outside form elements 10th includes. With the reference symbol E is a sectional plane outlined. For further explanation, please refer to the 2nd and 3rd referred.
• 2nd shows a section through a mold 1 , like in the 1 outlined, taking four form elements 10th are recognizable. It can also be seen that within the mold 1 two further shaped elements, in particular a first shaped element 11 and a second shaped element 12th are arranged. In particular, these are cores, for example made of a molding material such as sand. These are shaped in such a way that they abut each other. In particular, the second shaped element prevents 12th that the first form element 11 due to the buoyancy acting during casting shifted upwards. The form elements 10th , 11 and 12th form a cavity 2nd . The cast part is in the right half of the picture 3rd shown hatched. It can be seen that through the form elements 11 and 12th formed cavities are connected. This may not be wanted. Such a connection or such a channel has to be closed in some way, for example from the outside, by introducing a closure element, such as a beta plug.
• 3rd essentially shows that from the 2nd known arrangement, so that the explanation of the technical features is not discussed further. It is crucial that the first form element 11 and the second shaped element 12th now via an intermediate element 30th contacted or connected. In particular, the first shaped element 11 compared to the second shaped element 12th by means of the intermediate element 30th support. The second feature 12th is expediently fixed in position, this is not visible in this sectional view. In the right half of the picture is a correspondingly cast component 3rd shown, which can be seen that by the first shaped element 11 and the second shaped element 12th shaped cavities are not interconnected because of the intermediate element 30th was dissolved in the melt. Forms the second feature 12th for example an oil chamber core of a cylinder head and the first shaped element 11 a water jacket core, this is also not desirable. Compared to the component, as in the 2nd is outlined, advantageously no rework is required.

4th shows a schematic partial view of a first molded element 11 and a second formula element 12th which have an intermediate element 30th are contacted, cf. in this regard also the 3rd . It is also sketched that the intermediate element 30th a channel 32 having. This is provided in particular for degassing the cavity of the casting mold. The second shaped element expediently has 12th a corresponding channel. According to an advantageous embodiment, the intermediate element 30th formed from a porous material. In this respect, the channel 32 must not necessarily be directed into the cavity. Degassing can take place directly in the material of the intermediate element 30th and take place through it. However, the discharge of any gases through the channel 32 and in particular the forwarding to another form element, as in the 4th outlined by the canal 32 facilitated. The intermediate element is advantageous 30th around a polystyrene element. Preferably, this has a structurally simple design, such as a conical or cylindrical shape.

Reference list

1

Mold

2nd

cavity

3rd

Component

10th

Shaped element

11

first form element

12th

second form element

30th

Intermediate element

32

channel

E

Cutting plane

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102012015328 A1 [0002]

Claims (11)

Casting mold (1) comprising a multiplicity of shaped elements (10) which are designed to form a cavity (2) for a component (3), at least one first shaped element (11) by means of an intermediate element (30) on a second shaped element (12) abuts, and the intermediate element (30) is designed such that it dissolves when the cavity (2) is filled with melt. Casting mold after Claim 1 , wherein the intermediate element (30) is designed to hold or support the first shaped element (11) against displacement during casting by means of the second shaped element (12). Casting mold after Claim 1 or 2nd , wherein the second mold element (12) is positioned such that it supports the first mold element (11) via the intermediate element (30) against the buoyancy acting during casting. Casting mold (1) according to one of the preceding claims, wherein the intermediate element (30) is formed from a plastic, in particular polystyrene. Casting mold (1) according to one of the preceding claims, wherein the intermediate element (30) is formed from a porous material. Casting mold (1) according to one of the preceding claims, wherein the intermediate element (30) has at least one channel (32) which is designed for degassing the casting mold (1). Casting mold (1) according to one of the preceding claims, wherein the intermediate element (30) has two contact surfaces, which are each provided for contact with the first shaped element (11) and the second shaped element (12). Casting mold (1) according to one of the preceding claims, wherein the first mold element (11) and the second mold element (12) are sand cores which are designed to form cavities in the component (3). Casting mold (1) according to one of the preceding claims, wherein the first mold element (11) is a water jacket core of a cylinder head and the second mold element (12) is an oil chamber core of the cylinder head. Method for casting a component, in particular in gravity casting, comprising the steps: - Providing a plurality of shaped elements (10) for forming a cavity (2) for casting a component (3); - arranging at least one intermediate element (30) in the cavity (2) for fixing, positioning and / or holding at least one of the shaped elements (10) in an intended position and using a material for the intermediate element (30) which dissolves during casting; - Casting the component (3). Procedure according to Claim 10 , comprising the step: - arranging a first fluid space core (11) on a second fluid space core (12) via at least one intermediate element (30).

Images