EP2506999A1

EP2506999A1 - Casting unit for a die casting machine

Info

Publication number: EP2506999A1
Application number: EP10787072A
Authority: EP
Inventors: Norbert Erhard; Helmar Dannenmann; Jürgen KURZ; Andreas Sydlo; Daniel Gerner
Original assignee: Oskar Frech GmbH and Co KG
Current assignee: Oskar Frech GmbH and Co KG
Priority date: 2009-11-30
Filing date: 2010-11-24
Publication date: 2012-10-10
Anticipated expiration: 2030-11-24
Also published as: EP2506999B1; DE102009057197B3; ES2617328T3; JP2013512106A; PL2506999T3; WO2011064253A1; RU2570266C2; BR112012013027B1; HRP20170511T1; BR112012013027A2; RU2012124327A; KR20120098820A; CN102712039B; JP2015096279A; JP5947216B2; US9233417B2; CN102712039A; MX2012006125A; US20120273530A1; KR101746786B1

Abstract

The invention relates to a casting unit for a die casting machine, wherein the casting unit comprises a casting chamber body (1) comprising a casting chamber (2) that can be filled with casting material and having a casting material inlet (8) and a casting material outlet (3), and a casting piston (4) that can be moved forward in a longitudinal direction of the casting piston, in order to discharge casting material from the casting chamber under pressure by means of the casting material outlet, and can be moved back, whereby the casting material can be fed into the casting chamber by means of the casting material inlet. According to the invention, the casting piston (4) extends through the through-passage (5) of the casting chamber body (1) into the casting chamber from the outside, wherein a free space area (6) of the casting chamber is formed between an outer surface (4b) of the casting piston moved forward into the casting chamber and an inner wall surface (1c) of the casting chamber body opposite thereto transverse to the longitudinal direction of the casting piston, in that an outer cross section (d) of the casting piston is correspondingly smaller than the inner cross section (D) of the casting chamber body. The invention further relates to the use thereof, e.g. for metal die casting machines.

Description

Casting unit for a die casting machine

The invention relates to a pouring unit for use in a die casting machine, wherein the pouring unit includes a casting chamber body and a casting piston. The casting chamber body has a casting material fillable casting chamber with a casting material inlet and a casting material outlet. The casting piston is advanceable in the casting chamber in a casting piston longitudinal direction to discharge casting material under pressure from the casting chamber via the casting material outlet, and retractable, whereby casting material can be fed into the casting chamber via the casting material inlet.

Such pouring units are typically used in the corresponding die casting machines, for example of the hot chamber or cold chamber type, to promote a molten metal by the action of the casting piston from the casting chamber at high speed and high pressure in a mold cavity. In the mold cavity, solidification of the molten metal then forms the desired metallic casting. Depending on casting material, eg alloys of zinc, Al or magnesium, and The casting unit has to endure relatively high temperatures and pressures of the molten metal of, for example, more than 600 ° C. and 1000 bar, which is known to require special constructive measures.

In conventional casting units, the casting piston is typically designed as a slide piston which can be axially moved back and forth in a hollow-cylindrical casting chamber body, its outer cross-section corresponding to the internal cross-section of the casting chamber body. In other words, this spool forms an axially movable end wall of the casting chamber which variably delimits the casting chamber volume, this conventional casting piston type sealing the casting chamber volume towards this end face by its external cross section corresponding to the internal cross section of the casting chamber body, possibly assisted by associated sealing means, e.g. are arranged on the piston outer circumference. The power transmission to the casting piston via a provided on the casting chamber facing away from the front end of the casting piston piston shaft with respect to the casting piston of smaller cross-section. The casting piston shaft may e.g. be led out by an associated passage opening in Gießkammerkörper from the latter, in which case this passage opening has a corresponding to that of the piston skirt cross section, which is smaller than the casting piston outer cross section and the inner cross section of the cylindrical casting chamber body.

Various conventional casting units are known e.g. in published patent applications DE 10 2005 009 669 A1, DE 195 44 716 A1 and DE 43 16 927 A1 and in patent EP 1 483 074 B1.

Casting units with said spool type pose some specific technological challenges. One problem is the effect of so-called edge shell solidification. Due to the comparative The cooler cylinder wall of the casting chamber body can solidify melt material on its inner wall and disturb or aggravate the movement of the casting piston sealingly moving along it with two-dimensional surface contact. In addition, when the casting piston is moved back, apart from the casting material, air is usually also present in the casting chamber, which must be expelled again during the mold filling operation, ie during advancing of the casting piston, or can lead to melt oxidation problems.

The invention is based on the technical problem of providing a casting unit for a die casting machine, which can eliminate or at least reduce the above-mentioned difficulties of conventional casting piston-type casting units.

The invention solves this problem by providing a pouring unit having the features of claim 1. In this pouring unit, the pouring piston extends through a feedthrough opening of the pouring chamber body from outside into the pouring chamber, with a free space region of the pouring chamber being moved between an outer casing surface of the pouring chamber into the pouring chamber Casting piston and one of these transverse to the casting piston longitudinal direction opposite inner wall surface of the casting chamber body is formed by an outer cross section of the casting piston is correspondingly smaller than an inner cross section of the casting chamber.

In other words, in the casting unit according to the invention, the casting piston is of a displacer type which accordingly reduces the casting chamber volume by moving forward into the casting chamber without sealingly abutting its outer cross section in the manner of a conventional slide piston against the inner cross section of the casting chamber body. By leaving the free space area, any friction problems between the exterior - - ßenquerschnitt of the casting piston and the transverse to the casting piston longitudinal direction opposite internal cross section of the casting chamber body, for example due to the mentioned edge shell solidification effect. A problem of friction due to two-dimensional, surface frictional contact can thus be limited locally to the region of the leadthrough opening. This is much easier to control than the conventional friction problem between the outer side of the casting piston and the inner cross-sectional area of the casting chamber body along the entire displacement length in the conventional slide piston type. If required, a one-dimensional, line-shaped or zero-dimensional, point-shaped guide contact can be maintained between the casting piston and the casting chamber boundary wall. In addition, this design of the pouring unit according to the invention comparatively easily offers the possibility of always keeping the casting chamber completely filled with casting material without necessarily causing ambient air to enter the casting chamber.

In one development of the invention, the casting material inlet opens into the free space region and / or into the casting material outlet of the casting chamber. This has the advantageous consequence that the pouring chamber inlet is not blocked even with maximum advancing casting piston of the latter. Thus, casting material can be fed from its maximum advancing position via the pouring inlet into the casting chamber already at the beginning of the return movement of the casting piston. In contrast, in conventional pouring piston-type casting units, the pouring inlet is mostly blocked by the advancing pouring piston and is released therefrom only when the pouring piston has moved back a certain distance from its maximum advancing position. The present casting unit thus enables a comparatively uniform, homogeneous feeding of casting material into the casting chamber and thus also the avoidance of undesirable turbulences and an undesirable suction of ambient air over the - -

Casting material outlet when moving back the casting plunger. The casting chamber can thus always be kept completely filled with casting material without further notice.

In a further embodiment, the casting material inlet and / or a casting material supply line assigned to it are provided with a shut-off element which prevents casting material from emerging from the casting chamber via the casting material inlet. Depending on requirements and application, it may be an active or passive shut-off element of conventional type, e.g. around a corresponding check valve.

In a further development of the invention, the casting chamber body has a hollow cylinder, and the passage opening is provided at a front end thereof. The casting piston can then extend, for example, with the piston longitudinal axis parallel to the hollow cylinder longitudinal axis, axially via the passage opening into the casting chamber. In a further embodiment, the casting material outlet and / or the casting material inlet is provided on the end face of the hollow cylinder opposite the feed-through opening or on a cylinder jacket surface of the hollow cylinder. These positioning measures can contribute to a favorable flow characteristic for the pouring material to be introduced into the casting chamber and from this under pressure into a mold cavity.

In a further development of the invention, a guide sleeve is provided for the casting piston, which extends from one of the casting chamber outside of the passage opening to the outside and / or from one of the casting chamber facing inside the passage opening into the casting chamber inside. With this guide sleeve, the casting piston can be additionally supported and guided during its forward and backward movement. - -

In a further development of the invention, a sealing element is provided for sealing the Gießkolbendurchführung. In one possible implementation, the sealing element is arranged on a casting chamber-facing inside of the passage opening or the guide sleeve. Arranging on the inside has the advantage that solidified melt material, if it should come to a solidification effect in this area, can easily be pushed back into the casting chamber during advancement of the casting piston without resulting in disturbing phenomena of friction between the casting piston and the inner wall of the casting chamber body Has. Even when moving back the casting piston makes melt material that eventually solidifies in the region of the sealing element on the inside of the lead-through opening or the guide sleeve, no problems, if only because this return movement can take place quasi unpressurized in contrast to the advance of the casting. Because the casting material in the casting chamber is not in the return movement of the casting piston under the high pressure, as it prevails during the Formfüllphase when advancing the casting piston, but is depressurized or at most under a much lower supply pressure, optionally for feeding of casting material into the casting chamber can be used.

In a development of the invention, a casting piston temperature control device is provided for at least partially active temperature control of the casting piston. As a result, depending on requirements and application, the temperature of the casting piston can be actively influenced, the part of which in each case being in the casting chamber being subject to the action of temperature by the hot casting material there. In an embodiment of this measure, the casting piston temperature control device is designed to be able to actively temper the casting piston in accordance with a predeterminable temperature profile along at least part of its length. For example, this may lead to a temperature gradient along the - -

Gießkolbens leading temperature influence of the hot casting material in the casting chamber on the casting piston suitable partially compensated or fully compensated.

In a development of the invention, a casting chamber temperature control device is provided for active temperature control of the casting chamber. This can be used, for example, to prevent melting solidification effects in the casting chamber or to achieve a relatively homogeneous temperature distribution of the casting material in the casting chamber.

In a further development of the invention, the casting unit has a relief ring groove and a discharge channel, wherein the relief ring groove is located on a casting piston facing inner wall of the passage opening or the guide sleeve and the discharge channel leads from the Entlastungsringnut out to the outside of the casting chamber. If e.g. due to wear some melt material or other fluid between the casting piston and feedthrough opening or guide sleeve passes, this can be discharged through the relief ring groove and the discharge channel controlled to the outside.

Advantageous embodiments of the invention are illustrated in the drawings and will be described below. Hereby show:

1 is a schematic side view of a pouring unit for a

die casting machine,

2 shows a view corresponding to FIG. 1 for a variant of the casting unit with relief ring groove and relief channel, FIG. - -

3 shows a view corresponding to FIG. 2 for a variant of the casting unit, in which a casting material inlet opens into a casting material outlet region instead of a free space region of the casting chamber, FIG.

Fig. 4 is a view corresponding to Fig. 2 for a variant of the casting unit with a primarily in the casting chamber instead of from the casting chamber outwardly extending casting piston guide sleeve and

Fig. 5 is a view corresponding to FIG. 4 for a variant of the casting unit without active Gießkammertemperierung.

The casting unit shown schematically in FIG. 1 is particularly suitable for processing liquid and semi-molten metal melts, such as alloys of tin, zinc, lead, aluminum, magnesium, titanium, steel or copper or several of these metals, mixtures of several metals and optionally such materials with admixtures of particles, in an associated die casting machine. The casting unit can be installed, for example, as a so-called vertical or horizontal casting unit in the caster in question, depending on requirements and in particular depending on Druckgießmaschinentyp. The casting unit has a casting chamber body 1, which in the example shown comprises a hollow cylinder 1 a, which forms a casting chamber 2 with its interior. At a right in Fig. 1 end face a Gießmaterialauslass 3 is provided, can be supported on the casting material from the casting chamber 2 in a conventional, not further shown manner in a mold cavity formed in the usual way by a fixed and a movable mold half of the die casting machine is defined and the contour of a casting to be produced. - -

Furthermore, the casting unit comprises a casting piston 4, which is realized as an elongated displacement piston and extends through a passage opening 5 of the casting chamber body 1 from the outside into the casting chamber 2. In the example shown, the passage opening 5 is provided at the end opposite the Gießmaterialauslass 3 front side of the hollow cylindrical Gießkammerkörpers 1, and indeed as the Gießmaterialauslass 3 centrally to a longitudinal axis 1 b of the casting chamber hollow cylinder. 1 The casting piston 4 is held axially reciprocable with the hollow cylinder longitudinal axis 1 b aligned longitudinal axis 4a, as symbolized by a movement double arrow B, where it is shown in Fig. 1 in a rearward end position.

The casting piston 4 has an outer diameter d which is constant at least via a part of the casting piston 4 that can be moved into the casting chamber 2 or through the lead-through opening 5 and essentially corresponds to the diameter of the lead-through opening 5. Optionally, this part of the casting piston 4 may also have a slightly conical shape, in which case provision must be made for a suitable sealing. In contrast, the casting chamber hollow cylinder 1 a has a larger inner diameter D, ie D> d, so that an annular gap 6 remains between the advancing in the casting chamber Gießkolbenabschnitt and the radially opposite Gießkammerwand as a free space region of the casting chamber, which permanently belongs to Gießkammervolumen he is not shut off from the casting piston. In other words, lie in a dashed line in Fig. 1 indicated, advanced Gießkolbenstellung 4 'an outer circumferential surface 4b of the casting piston 4 and an inner wall surface 1 c of the hollow cylindrical casting chamber body 1 with a radial free space distance Dd opposite, wherein the free space annular gap 6 formed in the Operation is permanently filled with the casting material located in the casting chamber 2. It is understood that the casting piston 4 in its not in the casting chamber 2 into movable rear section a - - may have any cross-sectional configuration, such as a stepped or conical shape.

In the rear piston end position shown, a casting chamber side front end 4c of the casting piston 4 is located at a small distance from the passage opening 5 in the casting chamber 2. From this rear end position, the casting piston 4 can each be advanced so far that the desired amount of liquid or partially liquid casting material is discharged in the associated mold filling from the casting chamber 2 in the Formkavitat, ie The volume of casting material to be discharged is equal to the volume of the casting plunger 4 moved into the casting chamber 2. The casting plunger 4 can be advanced to a position in which its front face end 4c reaches the inner wall of the casting chamber body 1 at the end face which is the Gießmaterialauslass 3, wherein the piston diameter d in this example is greater than a diameter a of the Gießmaterialauslasses 3. Alternatively, it may be provided to choose the diameter a of the Gießmaterialauslasses 3 greater than the piston diameter d. In this case, the casting piston 4 can advance with its front end 4c into the Gießmaterialauslass 3, if appropriate for the particular application. The front end position of the casting piston 4 can be defined by the stroke of a conventional, not shown drive for the casting piston 4 or by a corresponding limit stop.

Casting material can be supplied to the casting chamber 2 via a casting material feed line 7 and an associated casting material inlet 8, which is introduced into a cylinder jacket surface of the hollow cylinder 1 a. This has the consequence that the casting material inlet 8 opens into the annular gap-shaped free space region 6 of the casting chamber 2 and is therefore not blocked off by the advancing casting piston 4. The casting material inlet 8 and / or the casting material supply line 7 are provided with a - - Actively or passively acting shut-off element 9 is provided with the prevents that located in the casting chamber casting material during advancement of the casting piston 4 in the casting chamber 2 via the Gießma- terialeinlass 8 can escape. For example, the shut-off element 9 can be realized as a check valve as shown schematically.

For sealing the passage of the casting piston 4 through the passage opening 5, a sealing element 10, e.g. a sealing rubber or metal ring, provided on a casting chamber side inside the passage opening 5. The sealing element 10 is preferably designed, e.g. As a correspondingly shaped sealing lip member that it presses under the pressure of the casting material in the casting chamber 2 sealingly against the performed casting piston 4 and / or embedded in the passage opening 5 or inserted. For the sealing element 10 is an elastic or non-elastic design with suitable geometry can be used as needed.

To guide the axially movable casting piston 4, a guide sleeve 1 1 is provided with the piston diameter d corresponding sleeve inner diameter, which is realized in the example shown as an axial extension or flange of the casting chamber 1. At the same time, the guide sleeve 1 1 is used in the illustrated embodiment for receiving a guide sleeve tempering device 12, which serves for active Führungshülsentemperierung and axially extending as shown in the region of the passage opening 5. The tempering device 12 can also contribute to the temperature of the guided in the guide sleeve 1 1 casting piston 4. It may be, for example, of a type with a liquid or gaseous tempering medium which is passed through tempering passages which surround the casting plunger 4 coaxially in the corresponding section of the guide sleeve 11 or through the passage opening 5. - -

For active Gießkolbentemperierung, as shown in the embodiment shown, a corresponding Gießkolben tempering device 14 may be provided, which in turn is for example of a type with a liquid or gaseous temperature control, which is passed through one or more temperature control channels 14a, which in the casting piston 4 itself extend. In the exemplary embodiment shown, this is realized in that a tempering tube 15 is longitudinally inserted into an interior 16 of the casting piston 4 realized for this purpose as a hollow cylinder, leaving an annular gap between the temperature control tube 15 and the casting piston inner wall. The annular gap represents a first temperature control channel, while the temperature control tube 15 represents a second temperature control channel, whereby the temperature control medium can be guided via one of the two temperature control channels into the front casting piston area and can be led back to the rear via the other temperature control channel.

The mentioned tempering 12, 14 can be used to actively temper the casting piston 4 and the guide sleeve 1 1 in the relevant section, for example, according to a predetermined temperature profile along at least a portion of its vorbewegbaren in the casting chamber length. In particular, this can be counteracted depending on the needs and application of the influence of temperature of the hot casting melt in the casting chamber 2 on the movable into the casting chamber part of the casting piston 4, for example, for the purpose of not causing excessive axial temperature gradients in the casting piston 4, due to locally different piston material expansion could complicate the sealing of the casting piston 4 at the passage opening 5. The two temperature control devices 12, 14 can be suitably matched to one another for this purpose of a desired temperature control of the casting piston 4 and expediently also of the guide sleeve 1 1, wherein in alternative embodiments. - Forms only one of the two tempering 12, 14 may be provided.

Furthermore, a casting chamber temperature control device 13 is provided, with which the casting chamber 2 together with casting material inlet 8 together with adjoining casting material supply line 7 and casting material outlet 3 together with adjoining casting material outlet line can be controllably actively controlled in a desired manner. For this purpose, this tempering device 13 can also be used e.g. be of a type with a liquid or gaseous tempering, which is passed through tempering, which surround the hollow cylinder 1 a and the Gießmaterialzufuhrleitung 7 and / or the Gießmaterialauslassleitung coaxial. With this tempering device 13, it is consequently possible to keep the casting material at a comparatively constant temperature level without strong temperature gradients, when it is fed into the casting chamber 2 via the supply line 7 for the next casting operation, stored there and then discharged via the casting material outlet 3 in the mold filling process becomes. If required, the tempering device 13 can be divided into a plurality of separately controllable tempering zones or tempering units.

As already apparent from the above description of the structural conditions, in the casting unit shown, the casting piston 4 acts as a pure displacement piston whose feed into the casting chamber 2 determines the melt quantity to be discharged from the casting chamber 2 as usual under high speed and high pressure , wherein the casting piston 4 moves freely into the casting chamber 2, without being guided with its lateral surface on a cylinder inner wall of the casting chamber body 1 along. Disturbing frictional effects on a corresponding sliding surface between casting piston and casting chamber wall, as they are the conventional casting units from Schieberkol- - inherent in the casting unit of the positive displacement piston type are inherent in this casting unit.

In addition, it can be relatively easily avoided that when the mold piston 4 is moved back into the casting chamber 2 after the mold filling process has ended. Because the advancing casting piston 4 does not block the casting material inlet 8, so that when moving back the casting piston 4 immediately casting material can be fed via the supply line 7 and the then opening shut-9 in the casting chamber 2. This introduction of casting material takes place e.g. substantially depressurized or with a slight overpressure, and in each case the suction of air can be e.g. be avoided via the pouring material inlet 3, if desired. The desserts can also be improved by the fact that forms a closing plug at the Gießmaterialauslass by Gießmaterialerstarrung towards the end of the respective casting cycle, which prevents the ingress of air.

The displacement piston principle implemented here facilitates the construction of a high pressure and the movement of the casting piston 4 at high speed to effect the mold filling, wherein the then closed shut-9 holds the casting material 8 closed, so that the casting material displaced by the casting piston 4 alone on the Gießmaterialauslass 3 from the pouring chamber 2 out to fill the mold cavity. Furthermore, the casting piston configuration according to the invention has the advantage that no piston lubricant is needed and consequently no corresponding residues can occur in the casting produced.

FIGS. 2 to 5 illustrate various advantageous variants of the casting unit of FIG. 1, wherein the same reference symbols are used to facilitate understanding of identical or functionally equivalent elements. - - are used and to that extent can be made to the above comments on casting unit of FIG. 1.

The casting unit shown in FIG. 2 has, in addition to that of FIG. 1, a relief annular groove 17 and an associated relief channel 18. The relief ring groove 17 is annularly introduced in this example in the inner wall of the guide sleeve 1 1, and at an axial height between the passage opening 5 of the casting chamber 1 and the axially outer end face of the guide sleeve 1 1. The discharge channel 18 leads from the relief ring 17 to the outside ie in the outer space outside the casting chamber 1, to which the relief channel 18 is introduced, for example, as a radial bore through the wall of the guide sleeve 1 1.

The relief annular groove 17, together with the discharge channel 18, forms a leakage-discharging means for the controlled removal of any material, such as melt material, which may undesirably enter the space between the casting piston 4 and the through-hole 5 or guide sleeve 11, e.g. due to wear on the outside of the casting piston 4, on the sealing element 10 and / or on the inside of the passage opening 5 and der Führungshülse 1 1. 1

The casting unit shown in FIG. 3 differs from those of FIGS. 1 and 2 in that the casting material inlet 8 does not open into the clearance area 6, but into the region of the casting material outlet 3 of the casting chamber 2. This placement of the casting material inlet 8 ensures that it is not blocked off by the advancing casting piston 4. Otherwise, the features and advantages explained above on the exemplary embodiments of FIGS. 1 and 2 likewise apply to the casting unit of FIG. 3. - -

The pouring unit shown in Fig. 4 differs from those of Figs. 1 and 2 in that for the supported guidance of the casting piston 4, a guide sleeve 1 1 'is formed, which in this case extends primarily into the casting chamber 2, i. with a predeterminable axial guide sleeve length in between the casting piston 4 and casting chamber inner wall 1 c remaining free space area 6 inside. The sealing element 10 is arranged in this example in the region of the inner front end of this guide sleeve 1 1 'or embedded therein. The relief annular groove 17 and the discharge channel 18, which may optionally be provided in this variant of the casting unit, are in the range of a relatively short axial, from the actual casting chamber hollow cylinder 1 a outwardly facing part of the guide sleeve support of the casting piston 4th

Since in this embodiment the predominant part of the guide sleeve 1 1 'is in the casting chamber 2 and can therefore be heated during operation by the melt material present there, the guide sleeve tempering device 12, as shown in FIGS. 1 to 3 , optional omitted.

The pouring unit shown in Fig. 5 corresponds to that of Fig. 4 with the exception that in this case the tempering device 13 is not provided for active Gießkolbentemperierung. This casting unit is suitable, for example, for applications which do not require active heating of the casting chamber 2. This variant can be used, for example, for applications in which the complete casting unit dips into a melt bath, so that the casting unit is heated passively via the hot melt material, ie the hot, liquid melt material surrounds the casting chamber 2 or the casting chamber body 1 and holds them or this warm from the outside. In addition, this can be introduced via the casting material inlet 8 from the melt bath into the casting chamber 2 - -

Melting material keep the casting chamber 2 warm from the inside, as is the case with the other embodiments shown.

It is understood that further variants of the casting unit according to the invention are possible in which the different modifications mentioned in relation to the variants of FIGS. 2 to 5 are combined in a different way. For example, e.g. in all cases the relief annular groove 17 with the discharge channel 18 optionally present or not. In this case, the relief annular groove 17 may alternatively to the mentioned circular design, e.g. also have a helical course. The confluence of the casting material inlet 8 into a region of the casting material outlet 3, as shown in FIG. 3, can also be provided in the variants of FIGS. 4 and 5. In addition, in the variant with non-actively heated casting chamber 2 shown in FIG. 5 instead of the shown, primarily in the casting chamber 2 facing guide sleeve 1 1 'may be provided a primarily outwardly facing guide sleeve, as the guide sleeve 1 1 in the variants of FIG. 1 to 3.

It is also understood that the invention is not limited to the embodiments shown in the figures or mentioned above. Thus, in other embodiments of the invention, further modifications thereof may be provided, for example, a casting piston having a non-circular cross-section and a correspondingly designed passage opening may be used, and / or the guide sleeve may be realized as a component separately from the casting chamber body, possibly as a component mounted thereon , In further embodiments of the invention, the casting material inlet and the casting material outlet may be interchanged with respect to their positions in the exemplary embodiment shown or may open into the casting chamber at any other positions. The casting piston may, in corresponding embodiments, also transversely to the longitudinal direction of the Gießmaterialauslasses - - and / or the pouring material inlet into the casting chamber extend into it. For each of the aforementioned tempering 12, 13, 14 in addition to those mentioned any other skilled in the art for this application type of construction can be used, in the case of a heater, for example, an electric heater with electric heating elements.

In the examples shown, the free space area is formed as a circumferentially continuous annular gap, i. the casting piston moves freely in the casting chamber 2 without support. In alternative embodiments, a point or line guide of the casting piston may be provided within the casting chamber, i. In such embodiments, the casting piston engages with an outer circumferential surface along one or more line contacts and / or along one or more point contacts against a transverse to the casting piston movement direction opposite boundary wall of the casting chamber. In these cases, although there is a certain friction between the casting piston and a casting chamber boundary wall, it is characterized by having only one-dimensional line contact or zero-dimensional point contact, less than in the conventional case of the slide piston type where the outer surface of the casting piston has a two-dimensional frictional contact surface over its entire surface abuts against the opposite Gießkammerwandung. Thus, the illustrated embodiment could be used in the sense of line contact e.g. be modified so that the hollow cylinder inner wall 1 c or the casting piston outer circumferential surface 4 b arranged distributed on the circumference, is provided with axial direction component guide webs, which keep the casting piston 4 guided within the casting chamber 2 in its axial movement. These guide webs then divide the annular gap clearance 6 into several corresponding segments.

Claims

claims

1. casting unit for a die casting machine, with

a casting chamber body (1) which has a casting chamber (2) which can be filled with casting material and has a casting material inlet (8) and a casting material outlet (3), and

a casting plunger (4) which is advanceable in the casting chamber in a casting plunger longitudinal direction to discharge casting material under pressure from the casting chamber via the casting material outlet, and is movable backward, whereby casting material can be fed into the casting chamber via the casting material inlet,

characterized in that

- The casting piston (4) through a passage opening

(5) of the casting chamber body (1) extends from the outside into the casting chamber (2), wherein a free space region

(6) of the casting chamber is formed between an outer circumferential surface (4b) of the casting piston advancing into the casting chamber and an inner wall surface (1c) of the casting chamber body opposite to the casting piston longitudinal direction, in that an outer cross-section (d) of the casting piston is correspondingly smaller than an inner cross-section (D ) of the casting chamber body.

2. casting unit according to claim 1, further characterized in that the casting material inlet opens into the free space area and / or in the Gießmaterialauslass.

3. Casting unit according to claim 2, further characterized in that the casting material inlet and / or a casting material supply line (7) associated therewith is provided with a shut-off element (9) which prevents escape of casting material from the casting chamber via the casting material inlet.

4. casting unit according to one of claims 1 to 3, further characterized in that the casting chamber body has a hollow cylinder (1 a) and the passage opening is provided at a front end of the hollow cylinder.

5. Casting unit according to claim 4, further characterized in that the Gießmaterialauslass and / or the casting material inlet is provided at the feedthrough opening opposite the front end of the hollow cylinder or on a cylinder jacket surface of the hollow cylinder.

6. casting unit according to one of claims 1 to 5, further characterized in that a guide sleeve (1 1) is provided for the casting piston, which faces away from the casting chamber outside of the passage opening to the outside and / or from a casting chamber facing the inside Passage opening extends into the casting chamber.

7. Casting unit according to one of claims 1 to 6, further characterized in that a sealing element (10) is provided for sealing the Gießkolbendurchführung.

8. casting unit according to one of claims 1 to 7, further characterized in that a casting piston temperature control device (14) for at least partially active temperature control of the casting piston and / or a guide sleeve tempering device (12) is provided.

9. casting unit according to claim 8, further characterized in that the tempering device is adapted to actively temper the casting piston according to a predetermined temperature profile along at least a portion of its vorbewegbaren in the casting chamber length.

10. Casting unit according to one of claims 1 to 9, further characterized in that a casting chamber temperature control device (13) is provided for active temperature control of the casting chamber.

1 1. Casting unit according to one of claims 1 to 10, further characterized in that a relief ring groove (17) on a casting piston facing inner wall of the passage opening or the guide sleeve and a relief of the relief ring groove to the outside of the casting chamber body leading discharge channel (18) are provided.