DE3132833A1 - Injection part for three-phase pressure diecasting machine - Google Patents

Abstract

In the case of a three-phase pressure diecasting machine without multiplier, in which the pressure is applied in the second and third casting phases by a pressure accumulator (20, 22) in each case, the high-pressure accumulator (22) can be charged via a multiplier arrangement (64, 66) from the pump arrangement (26) of the pressure diecasting machine, the said pump arrangement being designed for the machine movement and for the first and second casting phases. As a result, even in the case of high final pressures in the holding pressure phase, a relatively weak pump can be used for charging the high-pressure accumulator. The power used by the pump can be reduced considerably. <IMAGE>

Description

PATENT LAWYERS

, SCllt11.7, -5H) HLAH Ä TIIt) KNES

EUROPEAN PATENT ATTORNEYS

-J-

IDRA Pressen GmbH Azenbergstrasse 31

7000 Stuttgart

KARL-HEINZ SCHAUMBURG, Dlpl.-Ing.

WOLFQANQ-SCHULZ-DÖRLAM Engineer dlplOmo E.N.S.I. Grenoble

DR. DIETER THOENES, Dlpl.-Phya.

August 19, 1981 I 70 20 DE - THgw

Press-in part for three-phase die casting machine

P. O. BOX 801560 - D-8000 MÜNCHEN 80 ■ MAUERKfRCHERSTRASSE 31

The invention relates to a Einpreßteii for a three-phase die casting machine, comprising a pressing piston displaceable in a pressing cylinder, a low-pressure accumulator and a high pressure accumulator, wherein the press cylinder working space for the first and the second Injection phase via a controllable check valve with a pump arrangement of the die casting machine or the Low-pressure accumulator and can be connected to the high-pressure accumulator for the third injection or holding pressure phase.

In a known press-fit part of this type, not only is the pressure during the first press-fit phase, but also the boost pressure for the two accumulators is generated by the pump arrangement of the die casting machine, which also provides the pressure for the machine movements. This has the disadvantage that the pump arrangement for the Generation of the maximum pressure in the high-pressure accumulator must be designed. For the machine movements and the in the first and second press-in phase, however, a significantly lower pressure is sufficient. That means that with the known Embodiment the pump is oversized for a large part of the machine functions. This not only means higher acquisition costs, but also higher operating costs for the pump arrangement .

The invention is based on the object of specifying a press-fit part of the type mentioned with which it is possible to achieve a high final pressure in the holding pressure phase without affecting the machine movement as well to have to oversize the first and second press-in phase certain pump arrangement.

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This object is achieved according to the invention in that a pressure multiplier cylinder between the inlet side of the high-pressure accumulator and the pressure side of the pump arrangement is arranged.

The arrangement according to the invention makes it possible to achieve a high final pressure in the high-pressure accumulator with a pump arrangement that is only used for the machine movements and the first and second press-in phase required pressure is designed. These Arrangement enables the merits of a three-phase die casting machine with the multiplier with the advantages a three-phase die-casting machine without a multiplier.

The object underlying the invention can also be achieved in that the high pressure accumulator has a separate high pressure pump is chargeable. A second pump is required in this case, but means this is still a simplification compared to the conventional solution, since the machine movements as well as the pump arrangement serving the first and second press-in phase are not also designed for the high holding pressure needs to be designed, while the high-pressure pump is only specially designed for charging the high-pressure accumulator needs to be. At least the operating costs for both pumps together are significantly lower than for a pump arrangement that can take over all functions on its own.

The main advantage of the three-phase die casting machine without a multiplier is that all phases are separate and can be controlled independently of each other. This makes it possible to continue the third phase without interruption

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This is to be followed by the second phase and at the end of the second phase a quick and instantaneous one To achieve pressure increase.

For this purpose, it is advantageous if the check valve can be closed by the pressure in the high-pressure accumulator. In In this case you do not have to wait until the check valve through the at the end of the second phase is closed in the press cylinder bar text space increasing pressure. Rather, you can do it immediately before or at the same time When the high-pressure accumulator is switched on, the non-return valve closes so that a delay-free and pressure peak-free Pressure increase occurs at the end of the second phase.

According to a preferred embodiment it is proposed that the check valve is arranged in a block-shaped head part of the press-fit cylinder, that the pressure accumulator are arranged directly on the block-shaped head part and that the supply lines from the pressure accumulator to the Press cylinder working space are formed within the head part and each have at least one outer surface of the Cut the head part, on each of which a speed adjustment valve is arranged. This results in a compact, extremely reliable and maintenance-friendly Construction with short pressure medium paths.

Further features and advantages of the invention emerge from the following description, which in conjunction with the attached figures show the invention using an exemplary embodiment explained. Show it:

Fig. 1 is a partially schematic sectional view of a press-in part according to the invention, and

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FIG. 2 shows the detail A from FIG. 1 on an enlarged scale.

1 shows a schematically illustrated press-fit part of a three-phase die casting machine with a Press cylinder 10 and a press piston 12 displaceable therein, the piston rod 14 of which with a casting piston 16 of the im other casting device, not shown, is connected. The press cylinder 10 is at its piston-side end closed by a head part 18, on or near which a low-pressure accumulator 20 and a high-pressure accumulator 22 are arranged and in the pressure medium lines for connecting the memory 20 and 22 with a press cylinder working space 24 are formed.

The supply of pressure medium to the working space 24 during the The first casting phase is carried out by a pump 26, which is also responsible for the machine movements of the die casting machine serves. The pressure medium passes from the pump 26 via a control valve 28 to a speed control system valve 30, which is arranged on the head part 18. From there, the pressure medium arrives via a line 32 and via a Check valve 34, shown in more detail in FIG. 2, to working space 24.

At the end of the first phase, when the piston 12 has an in has reached switch 36 lying in its path, the low-pressure accumulator 20 is activated via a switch 36 actuated, not shown control valve connected to the working chamber 24. Pressure medium flows out in the process the low-pressure accumulator 20 via a pressure medium channel 38 formed in the head part 18 to one on the outside of the head part 18 arranged speed control valve 40 and from there through another in the Head part 18 formed pressure medium channel 4 2 and the

Check valve 34 in the working space 24. The low-pressure accumulator 20 is charged by the pump 26 in a manner known per se and therefore not described in greater detail.

At the end of the second phase, when the piston 12 has an in Reached further switch 4 4 arranged on its way, the high-pressure accumulator 22 is via a not shown, The control valve actuated by the switch 44 is connected to the working chamber 24. The Pressure from the high pressure accumulator 22 via a pressure medium channel 46 formed in the head part 18 to a on the outside of the head part arranged speed control valve 48 and from there via another Pressure medium channel 50 directly into the working space 24. While usually when the high-pressure accumulator is switched on the check valve 34 is first closed by the increased pressure and only then ends the second phase is, according to the invention, the check valve 34 can be closed directly by the pressure of the high-pressure accumulator 22.

According to FIG. 2, a valve body 52 of the check valve 34 is connected to a control piston 54 which is in a bore 56 is arranged displaceably and on its side facing the valve body 52 via a line 58 and a directional valve 60 can be acted upon by the pressure of the high-pressure accumulator 22. As you can see, will when the pressure of the high-pressure accumulator is applied to the piston 54 22 the check valve 34 is closed. The directional control valve 60 can be operated by an in the path of the plunger 12 lying switch 6 2 are switched forth, which is arranged, for example, directly in front of the switch 44 which connects the high-pressure accumulator 22 to the working chamber 24. This ensures

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that the check valve 34 is closed immediately before the start of the third phase, so that with the connection of the high-pressure accumulator, the pressure build-up for the holding pressure can start without delay.

It will be understood that switches 36, 6, 2 and 44 are also on other locations along the piston path can be arranged and that the high pressure accumulator 22 also, if necessary. About a pressure switch can be switched on. Both accumulators 20 and 22 can be used as piston or bladder accumulators be trained.

The high pressure accumulator 22 is also according to the invention charged by the pump 26, which is designed so that it is a maximum of the machine movements and the can apply the required pressure first and second casting phase. In order to avoid the high boost pressure in the high-pressure accumulator Being able to achieve 22 is a multiplier cylinder 64 with a differential piston 66 displaceable therein between the pressure side of the pump 26 and the The inlet side of the high-pressure accumulator 22, i.e. the pressure medium channel 4 6, is arranged. For charging the high-pressure accumulator 22 can be achieved by the larger piston area of the differential piston 26 limited cylinder space can be connected to the pump 26 via a control valve, while the smaller piston area limited cylinder space via a control valve 70 and a check valve 72 via the Pressure medium channel 46 is connected to the high pressure accumulator 22. With a suitable choice of differential piston 66 can be the desired multiplication of the Pump 26 reach the delivered pressure. In the illustrated position of the control valve 68, the piston 66 is in the rest position on the left in FIG. 1 is withdrawn, with the retraction of the differential piston 66 then

occurs when the piston rod 74 of the differential piston a limit switch 76 is reached.

Instead of charging the high-pressure accumulator 22 with the aid of the multiplier cylinder 74, a dedicated high-pressure pump can also be used 78 be provided, which is driven by an electric motor 80 and in this case directly with the Control valve 70 is connected.

In both embodiments, the total power consumption of the pump arrangement is considerably lower than that of the known arrangement described above.

It should also be added that a switch 82 which can be actuated by the piston 12 when it moves into the starting position is provided which actuates a control valve which controls the outflow of the pressure medium from the working chamber 24. This can prevent the piston 12 from hitting the wall of the head part 18.

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Claims (5)

Claims 1.) Press-fit part for a three-phase die casting machine, comprising a pressing piston displaceable in a pressing cylinder, a low-pressure accumulator and a high-pressure accumulator, wherein the press cylinder working space for the first and the second press-in phase via a controllable Check valve with a pump arrangement of the die casting machine or the low pressure accumulator and can be connected to the high pressure accumulator for a third injection or holding pressure phase, thereby characterized in that between the input side of the high-pressure accumulator (22) and the pressure side a pressure multiplier (64, 66) is arranged in the pump arrangement (26). 2. Press-in part for a three-phase die casting machine, comprising a pressing cylinder displaceable in a press cylinder - Pistons, a low pressure accumulator and a high pressure accumulator, the press cylinder working space for the first and second injection phases via a controllable check valve with a pump arrangement of the Die casting machine or the low pressure accumulator and for a third injection or holding pressure phase with the High pressure accumulator can be connected, characterized in that the high pressure accumulator (22) can be charged via a separate high-pressure pump (78). 3. Press-fit part according to claim 1 or 2, characterized in that the check valve (34) can be closed by the pressure in the high-pressure accumulator (22). -I- 4. Press-in part according to claim 3, characterized in that the switching on of the second and third phase and / or the closing of the check valve (34) as a function of the plunger movement is controllable. 5. Press-in part according to one of claims 1 to 4, characterized characterized in that the check valve (34) is in a block-shaped head part (18) of the press-fit cylinder (10) is arranged that the pressure accumulator (20, 22) directly on the cylinder wall or the Head part (18) are arranged and that the supply lines from the pressure accumulators (20, 22) to the press cylinder working space (24) formed by pressure medium channels (38, 42; 46, 50) formed within the head part (18) are and each intersect at least one outer surface of the head part (18), on each of which a speed control valve (40, 48) is arranged. BATH ORIGINAL