EP0068147B1 - Device for pressure admission at the squeeze cylinder in a pressure die casting machine - Google Patents

Device for pressure admission at the squeeze cylinder in a pressure die casting machine Download PDF

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Publication number
EP0068147B1
EP0068147B1 EP82104584A EP82104584A EP0068147B1 EP 0068147 B1 EP0068147 B1 EP 0068147B1 EP 82104584 A EP82104584 A EP 82104584A EP 82104584 A EP82104584 A EP 82104584A EP 0068147 B1 EP0068147 B1 EP 0068147B1
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EP
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Prior art keywords
pressure
cylinder
compensating
reservoir
piston
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EP82104584A
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German (de)
French (fr)
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EP0068147A1 (en
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Friedrich Dipl.Ing. Stummer
Rolf Frey
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Mahle GmbH
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Mahle GmbH
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
    • B22D17/20—Accessories: Details
    • B22D17/32—Controlling equipment

Definitions

  • the invention relates to a device for pressurizing the press cylinder of a die casting machine according to the preamble of claim 1.
  • phase 1 In the initial phase of the casting process (phase 1), only a low speed of the plunger is provided in order to avoid splashing of the melt. In the actual filling phase (phase 2), high velocities of the plunger are selected in order to carry out the filling process quickly, while in the final and holding pressure phase (phase 3) considerably higher baling pressures are required and therefore the plunger is subjected to high pressure.
  • Generically comparable facilities for pressurizing die casting machines are e.g. B. described in DE-OS-23 56 711. According to this, a typical construction of such a device is that the plunger is driven by hydraulic fluid coming from a pressure accumulator.
  • the pressure in the pressure accumulator is generated by compressed gas stored above the hydraulic fluid.
  • the gas pressure in the pressure accumulator is generated by filling hydraulic fluid under pressure from a pump directly in the pressure accumulator. It is considered disadvantageous in this device that after the completion of the filling process in the filling phase 2 there is a pressure shock which affects a good casting. This is particularly the case when the pressure level in the accumulator is chosen to be high, in order to be able to realize the fastest possible mold filling process due to a large pressure difference between the accumulator and the plunger.
  • the invention has for its object to provide a pressurizing device working in all working phases with hydraulic fluid speed with a similarly simple construction, as described for such devices in DE-OS-23 56 711, in which safe damping of the pressure surge at the end of the 2nd and 3rd Working phase can be achieved while maintaining the highest possible pressure difference between the pressure accumulator and the plunger in the actual filling phase.
  • the drawing shows a flow diagram of an embodiment of the invention.
  • Press cylinder and plunger of the casting machine are designated 1 and 4.
  • the valves 2, 3, 5 and 6 and the lines leading to the press cylinder 1 are used essentially only for carrying out the first working phase and for returning the press piston 4 and emptying the compensating cylinder 8b).
  • Only the valve 5 also performs a function in the 2nd and 3rd working phases in such a way that it ensures a rapid drain of the hydraulic fluid from the press cylinder.
  • the valve 3, on the other hand, only ensures at the end of the 2nd and 3rd working phases that the line which opens from the pressure side of the plunger 4 is closed.
  • the high-pressure accumulator 7a, 7b and the compensation accumulator 8b, 8b are essential elements for realizing the invention.
  • the high-pressure accumulator 7a, 7b and the compensation accumulator 8a, 8b each exist from a cylinder (high-pressure cylinder 7b or compensating cylinder 8b), each with a piston 10 or 11 displaceable therein and downstream pressure vessels (high-pressure container 7a or compensating container 8a). Instead of the pistons 10, 11 other separators such. B. memory bubbles can be used.
  • the volume of the pressure containers 7a, 8a is designed such that the pressure level of the stored gas remains approximately constant over the entire displacement paths of the pistons 10 and 11, or changes slightly progressively in the compensating cylinder 8b.
  • the final pressure in the high-pressure accumulator 7a, 7b is built up by pushing back the piston 10 under the pressure of hydraulic fluid introduced into the high-pressure cylinder 7b.
  • the pressure in the compensating accumulator 8a, 8b is predetermined as a function of the desired holding pressure in the 3rd phase and is below the final pressure in the high-pressure accumulator 7a, 7b.
  • the pressure setting in the expansion tank 8a is carried out by the amount of hydraulic fluid that is introduced via the pressure setting valve 12.
  • the operation of the pressurizing device is as follows.
  • the first working phase takes place with the valve 9 closed and the valves 2 and 3 actuated in a manner known per se.
  • the transition to the second work phase is initiated by opening the valve 9 provided with an adjustable throttle.
  • the piston 11 of the compensating cylinder 8b is in the position shown in the drawing.
  • the piston 10 of the high-pressure cylinder 7b now presses the hydraulic fluid under the full pressure of the high-pressure container 7a into the press cylinder 1 on the press piston 4 at the beginning of the second work phase and high-pressure accumulators 7a, 7b a lower pressure than that set in the expansion tank 8a.
  • the piston 11 does not change its position during the second working phase.
  • a prerequisite for the functionality of the device is that the displacement paths of the pistons 10 and 11 are designed such that when the piston 10 is fully extended, the piston 11 is still freely movable at the end of the third working phase, i. H. has not yet reached its stop in the direction of the expansion tank 8a connected to it.
  • the pressure in the high pressure container 7a can e.g. B. set to 300 bar.
  • the pressure to be selected for the expansion tank 8a is approximately in a range between 80 and 270 bar.
  • the pressure level actually set depends on the level of the desired reprint at the end of the 3rd work phase.
  • the compensating cylinder 8b is connected in the narrowest cross section of a Venturi tube 13 arranged in the connecting line between the press cylinder 1 and valve 9. This ensures that the hydraulic fluid always flows in the direction of the press cylinder 1 at the high flow velocities in the venturi tube, since the static pressure on the piston 11 is lower than that which acts on the press piston 4.
  • the compensating cylinder 8b is emptied by switching the valves 6, 2 and 3 until the piston 11 is in the starting position.

Description

Die Erfindung betrifft eine Einrichtung zur Druckbeaufschlagung des Preßzylinders einer Druckgießmaschine nach dem Oberbegriff des Anspruchs 1.The invention relates to a device for pressurizing the press cylinder of a die casting machine according to the preamble of claim 1.

Der dreiphasige Gießvorgang setzt sich bei dieser Art von Druckgießmaschinen folgendermaßen zusammen. In der Anfangsphase des Gießvorganges (Phase 1) wird nur eine kleine Geschwindigkeit des Preßkolbens vorgesehen, um ein Spritzen der Schmelze zu vermeiden. In der eigentlichen Füllphase (Phase 2) werden hohe Geschwindigkeiten des Preßkolbens gewählt, um den Füllvorgang rasch durchzuführen, während in der End- und Nachdruckphase (Phase 3) erheblich höhere Preßdrücke erforderlich sind und deshalb der Preßkolben mit hohem Druck beaufschlagt wird.The three-phase casting process in this type of die casting machine is composed as follows. In the initial phase of the casting process (phase 1), only a low speed of the plunger is provided in order to avoid splashing of the melt. In the actual filling phase (phase 2), high velocities of the plunger are selected in order to carry out the filling process quickly, while in the final and holding pressure phase (phase 3) considerably higher baling pressures are required and therefore the plunger is subjected to high pressure.

Gattungsmäßig vergleichbare Einrichtungen zur Druckbeaufschlagung von Druckgießmaschinen sind z. B. in der DE-OS-23 56 711 beschrieben. Danach besteht ein typischer Aufbau einer derartigen Einrichtung darin, daß der Preßkolben durch aus einem Druckspeicher hommende Hydraulikflüssigkeit angetrieben wird.Generically comparable facilities for pressurizing die casting machines are e.g. B. described in DE-OS-23 56 711. According to this, a typical construction of such a device is that the plunger is driven by hydraulic fluid coming from a pressure accumulator.

Der Druck in dem Druckspeicher wird durch über der Hydraulikflüssigkeit lagerndes komprimiertes Gas erzeugt. Der Gasdruck in dem Druckspeicher wird durch Einfüllen von Hydraulikflüssigkeit unter Druck von einer Pumpe direkt in dem Druckspeicher erzeugt. Als nachteilig wird es bei dieser Einrichtung angesehen, daß es nach Abschluß des Füllvorganges in der Füllphase 2 zu einem ein gutes Gußstück beeinträchtigenden Druckschlag kommt. Dies ist besonders dann der Fall, wenn das Druckniveau in dem Speicher hoch gewählt wird, um durch eine große Druckdifferenz zwischen Speicher und Preßkolben einen möglichst schnellen Formfüllvorgang realisieren zu können. Durch Einstellung eines niedrigeren Speicherdruckes kann dann der Druckstoß nach der 2. Arbeitsphase zwar gemindert werden, allerdings mit der zwangsläufigen Folge, daß durch die entsprechend geringere Druckdifferenz zwischen Preßkolben und Druckspeicher auch der eigentliche Füllvorgang verlangsmat wird. Gerade dies ist jedoch besonders bei der Verarbeitung von Leichtmetallen nur unter Inkaufnahme einer schlechteren Gußqualität möglich.The pressure in the pressure accumulator is generated by compressed gas stored above the hydraulic fluid. The gas pressure in the pressure accumulator is generated by filling hydraulic fluid under pressure from a pump directly in the pressure accumulator. It is considered disadvantageous in this device that after the completion of the filling process in the filling phase 2 there is a pressure shock which affects a good casting. This is particularly the case when the pressure level in the accumulator is chosen to be high, in order to be able to realize the fastest possible mold filling process due to a large pressure difference between the accumulator and the plunger. By setting a lower accumulator pressure, the pressure surge can then be reduced after the second working phase, but with the inevitable consequence that the actual filling process is slowed down by the correspondingly lower pressure difference between the plunger and the accumulator. However, this is precisely what is possible, especially when processing light metals, by accepting poorer casting quality.

Zur Milderung des schädlichen Druckstoßes am Ende der 3. Arbeitsphase wird in der genannten DE-OS-2356711 vorgeschlagen, den Preßkolben nicht unter Zwischenschaltung einer Hydraulikflüssigkeit, sondern direkt durch aus dem Druckspeicher kommendes Gas anzutreiben. Dadurch soll durch geringere Masse des Hydraulikmediums und der Kompressionseigenschaft des Hydraulikmediums Gas der am Ende der 3. Arbeitsphase auftretende Druckstoß erheblich verminderbar sein. Abgesehen davon, daß bei dieser Lösung unerwünschte Gasfederungsvorgänge zu erwarten sind und daher das Druckstoßproblem nur unbefriedigend gelöst zu sein scheint, hat diese Einrichtung noch andere Nachteile. Insbesondere sind die drei Arbeitsphasen, nämlich Vorfüll-Formfüll- und Nachdruckvorgänge nicht unabhängig voneinander regelbar und durchführbar. Denn in allen drei Phasen muß praktisch mit der gleichen Druckdifferenz zwischen Preßkolben und Druckspeicher gearbeitet werden. Da in der eigentlichen Formfüllphase eine hohe Druckdifferenz - wie oben erläutert ist - erforderlich ist, besteht dieser Druck dann automatisch auch am Ende der 3. Arbeitsphase, in der sich der Druckstoß aufbaut, an. Darüberhinaus sind für den Rückzug des Preßkolbens hohe Kräfte erforderlich, da der Preßkolben gegen den vollen Arbeitsdruck im Druckspeicher verschoben werden muß. Überdies entstehen durch eine Gasdruckbeaufschlagung vieler Bauteile erhebliche Sicherheitsprobleme.In order to alleviate the damaging pressure surge at the end of the third working phase, it is proposed in DE-OS-2356711 mentioned not to drive the plunger with the interposition of a hydraulic fluid, but rather directly by gas coming from the pressure accumulator. As a result of the lower mass of the hydraulic medium and the compression property of the hydraulic medium gas, the pressure surge occurring at the end of the third working phase should be considerably reduced. Apart from the fact that undesirable gas suspension processes are to be expected with this solution and therefore the pressure surge problem seems to be solved only unsatisfactorily, this device has other disadvantages. In particular, the three work phases, namely pre-filling, form filling and reprinting processes, cannot be regulated and carried out independently of one another. Because in all three phases practically the same pressure difference between the ram and the pressure accumulator must be used. Since a high pressure difference - as explained above - is required in the actual mold filling phase, this pressure then also automatically exists at the end of the third working phase in which the pressure surge builds up. In addition, high forces are required for the retraction of the plunger, since the plunger must be moved against the full working pressure in the pressure accumulator. Furthermore, gas pressure on many components creates significant safety problems.

Ausgehend von diesem Stand der Technik liegt der Erfindung die Aufgabe zugrunde, eine in allen Arbeitsphasen mit Hydraulikflüssig keit arbeitende Druckbeaufschlagungseinrichtung mit ähnlich einrichtungsmäßig einfachem Aufbau, wie er bei solchen Einrichtungen in der DE-OS-23 56 711 beschrieben ist, zu schaffen, bei der eine sichere Dämpfung des Druckstoßes am Ende der 2.u.3. Arbeitsphase erreichbar ist bei gleichzeitiger Einhaltung einer möglichst hohen Druckdifferenz zwischen Druckspeicher und Preßkolben in der eigentlichen Füllphase.Based on this prior art, the invention has for its object to provide a pressurizing device working in all working phases with hydraulic fluid speed with a similarly simple construction, as described for such devices in DE-OS-23 56 711, in which safe damping of the pressure surge at the end of the 2nd and 3rd Working phase can be achieved while maintaining the highest possible pressure difference between the pressure accumulator and the plunger in the actual filling phase.

Gelöst wird diese Aufgabe durch eine Ausgestaltung der Einrichtung zur Druckbeaufschlagung nach den kennzeichnenden Merkmalen des Anspruchs 1.This object is achieved by designing the device for pressurizing according to the characterizing features of claim 1.

Weitere Ausgestaltungen der Erfindung enthalten die Unteransprüche.Further embodiments of the invention contain the subclaims.

Die Zeichnung zeigt ein Fließschema eines Ausführungsbeispiels der Erfindung.The drawing shows a flow diagram of an embodiment of the invention.

Preßzylinder und Preßkolben der im übrigen nicht dargestellten Gießmaschine sind mit 1 und 4 bezeichnet. Die Ventile 2,3,5 und 6 sowie die damit in Verbindung stehenden zu dem Preßzylinder 1 führenden leitungen dienen im wesentlichen nur zur Durchführung der ersten Arbeitsphase sowie der Rückführung des Preßkolbens 4 und dem Entleeren des Ausgleichszylinders 8b). Lediglich das Ventil 5 übt auch in der 2. und 3. Arbeitsphase eine Funktion dahingehend aus, daß es für einen schnellen Abfluß der Hydraulikflüssigkeit aus dem Preßzylinder sorgt. Das Ventil 3 sorgt dagegen bei Ablauf der 2. und 3. Arbeitsphase lediglich dafür, daß die von der Druckseite des Preßkolbens 4 einmündende Leitung verschlossen ist. Für die Realisierung der Erfindung wesentliche Elemente sind der Hochdruckspeicher 7a, 7b sowie der Ausgleichspeicher 8b, 8b. Beide Speicher münden in eine gemeinsame Zuleitung zu dem Preßzylinder 1 und sind in dieser Leitung durch ein Ventil 9 voneinander trennbar. Der Hochdruckspeicher 7a, 7b sowie der Ausgleichspeicher 8a, 8b bestehen jeweils aus einem Zylinder (Hochdruckzylinder 7b bzw. Ausgleichszylinder 8b) mit jeweils einem darin verschiebbaren Kolben 10 bzw. 11 und nachgeschalteten Druckgefäßen (Hochdruckbehälter 7a bzw. Ausgleichbehälter 8a). Anstelle der Kolben 10, 11 können andere Trennorgane wie z. B. Speicherblasen eingesetzt werden. Das Volumen der Druckbehälter 7a, 8a ist derart ausgelegt, daß das Druckniveau des gespeicherten Gases über die gesamten Verschiebewege der Kolben 10 und 11 etwa konstant bleibt, bzw. sich im Ausgleichszylinder 8b gering progressiv ändert. Der Enddruck in dem Hochdruckspeicher 7a, 7b wird durch Rückschieben des Kolbens 10 unter dem Druck von in den Hochdruckzylinder 7b eingebrachter Hydraulikflüssigkeit aufgebaut. Der Druck in dem Ausgleichspeicher 8a, 8b wird abhängig vom gewünschten Nachdruck in der 3. Phase vorgegeben und liegt unter dem Enddruck in dem Hochdrucksepeicher 7a, 7b. Die Druckeinstellung in dem Ausgleichbehälter 8a erfolgt durch die hydraulikflüssigkeitsmenge, die über das Druckeinstellventil 12 eingebracht wird.Press cylinder and plunger of the casting machine, not shown in the rest, are designated 1 and 4. The valves 2, 3, 5 and 6 and the lines leading to the press cylinder 1 are used essentially only for carrying out the first working phase and for returning the press piston 4 and emptying the compensating cylinder 8b). Only the valve 5 also performs a function in the 2nd and 3rd working phases in such a way that it ensures a rapid drain of the hydraulic fluid from the press cylinder. The valve 3, on the other hand, only ensures at the end of the 2nd and 3rd working phases that the line which opens from the pressure side of the plunger 4 is closed. The high-pressure accumulator 7a, 7b and the compensation accumulator 8b, 8b are essential elements for realizing the invention. Both stores open into a common supply line to the press cylinder 1 and can be separated from one another in this line by a valve 9. The high-pressure accumulator 7a, 7b and the compensation accumulator 8a, 8b each exist from a cylinder (high-pressure cylinder 7b or compensating cylinder 8b), each with a piston 10 or 11 displaceable therein and downstream pressure vessels (high-pressure container 7a or compensating container 8a). Instead of the pistons 10, 11 other separators such. B. memory bubbles can be used. The volume of the pressure containers 7a, 8a is designed such that the pressure level of the stored gas remains approximately constant over the entire displacement paths of the pistons 10 and 11, or changes slightly progressively in the compensating cylinder 8b. The final pressure in the high-pressure accumulator 7a, 7b is built up by pushing back the piston 10 under the pressure of hydraulic fluid introduced into the high-pressure cylinder 7b. The pressure in the compensating accumulator 8a, 8b is predetermined as a function of the desired holding pressure in the 3rd phase and is below the final pressure in the high-pressure accumulator 7a, 7b. The pressure setting in the expansion tank 8a is carried out by the amount of hydraulic fluid that is introduced via the pressure setting valve 12.

Die Arbeitsweise der Druckbeaufschlagungseinrichtung ist wie folgt.The operation of the pressurizing device is as follows.

Die 1. Arbeitsphase erfolgt bei geschlossenem Ventil 9 unter Betätigung der Ventile 2 und 3 in an sich bekannter Weise. Der Übergang in die 2. Arbeitsphase wird durch Öffnen des mit einer verstellbaren Drossel versehenen Ventiles 9 eingeleitet. Zu diesem Zeitpunkt befindet sich der Kolben 11 des Ausgleichzylinders 8b in der in der Zeichnung dargestellten Lage. Der Kolben 10 des Hochdruckzylinders 7b drückt nun zu Beginn der 2. Arbeitsphase die Hydraulikflüssigkeit unter dem vollen Druck des Hochdruckbehälters 7a in den Preßzylinder 1 auf den Preßkolben 4. Durch das Verschieben des Preßkolbens 4 in der 2. Arbeitsphase herrscht in der Leitung zwischen Preßzylinder 1 und Hochdruckspeicher 7a, 7b ein niedrigerer Druck als der in dem Ausgleichbehälter 8a eingestellte. Dadurch verändert der Kolben 11 während der 2. Arbeitsphase seine Lage nicht. Bei einem Druckstoß am Ende der 2. Arbeitsphase und während der 3. Arbeitsphase, d. h. der End- und Nachdruckphase, weicht der Kolben 11 dann unter dem sich verstärkt in dem Preßzylinder aufbauenden Druck aus und wirkt dadurch druckdämpfend bzw. abbauend. Auf diese Weise ist es möglich, Druckstöße am Ende der 2. Phase sowie den End- und Nachdruck sowie Druckstöße in der 3. Arbeitsphase auf einfachste Weise auf einen vorgegebenen Wert zu beschränken. Wichtig ist dabei, daß diese Beschränkung den Ablauf der 2. Arbeitsphase, in der mit einer möglichst hohen Druckdifferenz zwischen Preßkolben und Hochdruckspeicher 7a, 7b gearbeitet werden soll, in keiner Weise beeinträchtigt. Die Arbeitsdrücke für beide Phasen sind vielmehr unabhängig voneinander wählbar. Hierin liegt einer der wesentlichen Vorteile der erfindungsgemäßen Einrichtung. Eine Voraussetzung für die Funktionsfähigkeit der Einrichtung ist es, daß die Verschiebewege der Kolben 10 und 11 so ausgelegt sind, daß bei voll ausgefahrenem Kolben 10 am Ende der 3. Arbeitsphase der Kolben 11 noch frei beweglich ist, d. h. noch nicht seinen Anschlag in Richtung auf den ihm nachgeschalteten Ausgleichsbehälter 8a erreicht hat. Der Druck in dem Hochdruckbehälter 7a kann z. B. auf 300 bar eingestellt sein. In diesem Fall liegt der für den Ausgleichbehälter 8a zu wählende Druck etwa in einem Bereich zwischen 80 und 270 bar. Die tatsächlich eingestellte Druckhöhe richtet sich nach der Höhe des gewünschten Nachdruckes am Ende der 3. Arbeitsphase.The first working phase takes place with the valve 9 closed and the valves 2 and 3 actuated in a manner known per se. The transition to the second work phase is initiated by opening the valve 9 provided with an adjustable throttle. At this time, the piston 11 of the compensating cylinder 8b is in the position shown in the drawing. The piston 10 of the high-pressure cylinder 7b now presses the hydraulic fluid under the full pressure of the high-pressure container 7a into the press cylinder 1 on the press piston 4 at the beginning of the second work phase and high-pressure accumulators 7a, 7b a lower pressure than that set in the expansion tank 8a. As a result, the piston 11 does not change its position during the second working phase. In the event of a pressure surge at the end of the 2nd work phase and during the 3rd work phase, d. H. the end and hold pressure phase, the piston 11 then evades under the pressure that builds up in the press cylinder and thereby acts as a pressure-damping or reducing. In this way it is possible to limit pressure surges at the end of the 2nd phase as well as the final and final pressure as well as pressure surges in the 3rd working phase to a predetermined value in the simplest way. It is important that this restriction does not in any way affect the course of the 2nd work phase, in which the highest possible pressure difference between the ram and the high-pressure accumulator 7a, 7b is to be used. The working pressures for both phases can rather be selected independently of one another. This is one of the main advantages of the device according to the invention. A prerequisite for the functionality of the device is that the displacement paths of the pistons 10 and 11 are designed such that when the piston 10 is fully extended, the piston 11 is still freely movable at the end of the third working phase, i. H. has not yet reached its stop in the direction of the expansion tank 8a connected to it. The pressure in the high pressure container 7a can e.g. B. set to 300 bar. In this case, the pressure to be selected for the expansion tank 8a is approximately in a range between 80 and 270 bar. The pressure level actually set depends on the level of the desired reprint at the end of the 3rd work phase.

Außerdem treten zwischen dem Ende der 2. Arbeitsphase und dem Beginn der 3. Arbeitsphase keine Schaltzeiten auf, da keine Ventile verwendet werden müssen.In addition, there are no switching times between the end of the 2nd work phase and the start of the 3rd work phase, since no valves have to be used.

In dem dargestellten Ausführungsbeispiel ist der Ausgleichzylinder 8b im engsten Querschnitt eines in der Verbindungsleitung zwischen Preßzylinder 1 und Ventil 9 angeordneten Venturirohres 13 angeschlossen. Dadurch ist sichergestellt, daß die Hydraulikflüssigkeit bei den hohen Strömungsgeschwindigkeiten in dem Venturirohr stets zunächst in Richtung Preßzylinder 1 strömt, da der statische Druck auf dem Kolben 11 kleiner ist als derjenige, der auf den preßkolben 4 wirkt.In the exemplary embodiment shown, the compensating cylinder 8b is connected in the narrowest cross section of a Venturi tube 13 arranged in the connecting line between the press cylinder 1 and valve 9. This ensures that the hydraulic fluid always flows in the direction of the press cylinder 1 at the high flow velocities in the venturi tube, since the static pressure on the piston 11 is lower than that which acts on the press piston 4.

Nach durchgeführtem Einpreßzyklus wird durch Schalten der Ventile 6, 2 und 3 der Ausgleichszylinder 8b entleert bis der Kolben 11 in Ausgangsposition steht.After the press-in cycle, the compensating cylinder 8b is emptied by switching the valves 6, 2 and 3 until the piston 11 is in the starting position.

Claims (6)

1. Apparatus for the pressure-charging of the press cylinder of a die-casting machine, especially a cold-chamber die-casting machine with three- phase working system, in which the press-in part consists of a press cylinder (1) with single-stage press piston (4) and at least the filling-, final- and after-pressure necessary for the second and third phases is supplied from a fluid-filled high- pressure reservoir (7a, 7b) under gas pressure, while the pressure for the first phase can be supplied by a system separated from the high- pressure reservoir (7a, 7b), characterised by the following features :
(a) a compensating reservoir (8a, 8b) valvel- essly opens into a connecting conduit between high-pressure reservoir (7a, 7b) and press cylinder (1),
(b) the gas-charged high-pressure reservoir (7a, 7b) consists of a gas-filled high-pressure vessel (7a) and a high-pressure cylinder (7b) placed thereafter in the direction towards the press cylinder (1) with piston (10) displaceable therein to separate the hydraulic fluid from the gas of the high-pressure vessel (7a) loading the high-pressure cylinder (7b),
(c) the compensating reservoir (8a, 8b) consists of a gas-filled compensating vessel (8a) with compensating cylinder (8b) placed thereafter in the direction towards the press cylinder (1), with piston (11) displaceable therein to separate the hydraulic fluid from the gas of the compensating vessel (8a) loading the compensating cylinder (8b),
(d) the pressure in the compensating reservoir (8a, 8b) is lower than the pressure in the high- pressure reservoir (7a, 7b),
(e) into the connecting conduit leading from the high-pressure reservoir (7a, 7b) to the press cylinder (1), between the compensating reservoir (8a, 8b) opening into this connecting conduit and the high-pressure reservoir (7a, 7b) there is arranged a valve (9) which is opened only during the course of the second and third working phases.
2. Apparatus according to Claim 1, characterised in that for the return of the piston (10) in the highpressure cylinder (7b) into its working-initial position a connection for the introduction of hydraulic fluid is provided in the part of the hydraulic conduit lying between the valve (9) and the high-pressure cylinder (7b).
3. Apparatus according to one of the preceding Claims, characterised in that the level of the gas pressure in the compensating vessel (8a) is adjustable as desired by a connection of the compensating vessel (8a) to the hydraulic fluid through a pressure-limiting valve (12).
4. Apparatus according to one of the preceding Claims, characterised in that the connecting conduit between press cylinder (1) and high-pressure cylinder (7b) is made as a Venturi pipe (13) at the point where the compensating cylinder (8b) enters, and the entry point lies in the region of the narrowest flow cross-section of the Venturi pipe.
5. Apparatus according to one of the preceding Claims, characterised in that the return of the piston (11) into the initial position is effected by actuation of the valves (6, 2, 3).
6. Apparatus according to one of the preceding Claims, characterised in that in the initial position the piston (11) abuts on the upper stop of the compensating cylinder (8b) in the direction of the Venturi pipe (13).
EP82104584A 1981-06-30 1982-05-26 Device for pressure admission at the squeeze cylinder in a pressure die casting machine Expired EP0068147B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19813125598 DE3125598A1 (en) 1981-06-30 1981-06-30 DEVICE FOR PRESSURIZING THE PRESSING CYLINDER OF A PRESSURE CASTING MACHINE
DE3125598 1981-06-30

Publications (2)

Publication Number Publication Date
EP0068147A1 EP0068147A1 (en) 1983-01-05
EP0068147B1 true EP0068147B1 (en) 1984-07-25

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Application Number Title Priority Date Filing Date
EP82104584A Expired EP0068147B1 (en) 1981-06-30 1982-05-26 Device for pressure admission at the squeeze cylinder in a pressure die casting machine

Country Status (3)

Country Link
EP (1) EP0068147B1 (en)
JP (1) JPS586766A (en)
DE (2) DE3125598A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101146469B1 (en) * 2003-10-31 2012-05-21 알치벨 팔마, 에스.엘. Useful immunotherapeutic agent for the combined treatment of tuberculosis in association with other drugs

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3446836A1 (en) * 1984-12-21 1986-07-03 Mahle Gmbh, 7000 Stuttgart DEVICE FOR PRESSURE TIP PREVENTION IN THE PRESSING UNIT OF A DIE CASTING MACHINE
CN102379748A (en) * 2011-11-16 2012-03-21 中钢集团洛阳耐火材料研究院有限公司 Gas path system of differential pressure type pure titanium casting machine for dentistry

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2165929C3 (en) * 1971-12-31 1982-04-29 Maschinenfabrik Weingarten Ag, 7987 Weingarten Device for the accelerated construction and regulation of the holding pressure on die casting machines
JPS5312033B2 (en) * 1972-11-14 1978-04-26
DE2355594A1 (en) * 1973-11-07 1975-05-15 Valentin Emmerich Pressure casting machine control - has high pressure booster with stepped piston for finishing pressure phase accumulator
DE2406528C2 (en) * 1974-02-12 1982-04-01 Idra Pressen GmbH, 7000 Stuttgart Control device for a die-casting machine that works according to the multiphase principle
DE2922914A1 (en) * 1979-06-06 1980-12-11 Oskar Frech Werkzeugbau Gmbh & METHOD AND ARRANGEMENT FOR CONTROLLING THE INPRESSION PROCESS IN COLD CHAMBER DIE CASTING MACHINES

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101146469B1 (en) * 2003-10-31 2012-05-21 알치벨 팔마, 에스.엘. Useful immunotherapeutic agent for the combined treatment of tuberculosis in association with other drugs

Also Published As

Publication number Publication date
DE3125598A1 (en) 1983-01-13
DE3260458D1 (en) 1984-08-30
EP0068147A1 (en) 1983-01-05
JPS586766A (en) 1983-01-14

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