DE3315453A1 - Diecasting process for the production of high-strength diecastings, which can be tempered, by smooth guiding of the plunger, and apparatus for performing it - Google Patents

Abstract

Process and apparatus for the smooth guiding of the plunger (11) of a diecasting machine. The plunger (11) is guided, so as to be capable of rotating to and fro, in a press cylinder (12) and is acted on both sides by a hydraulic medium (16). When the piston rod (13) travels into the press chamber (not shown), the hydraulic medium (16) flowing out through the drain pipe (17) opposes a counterpressure by means of a drain throttle (24) arranged in the drain pipe (17). The drain throttle (24) is provided with a throttle gap (26) which can be varied by means of an adjustable opening path (25) of the drain throttle (24) which is guided in a throttle guide (29). <IMAGE>

Description

description

The invention initially relates to a die-casting method with a die-cast plunger assembly in which in a press piston cylinder a press piston from a multiplier piston

.5 with the help of hydraulic medium Nin the casting

chamber of a die-casting machine is retracted, whereby the hydraulic medium is depressurized on the side facing away from the multiplier piston a drain pipe and a check valve is passed.

In such a die-casting process, the The plunger is moved into the casting chamber with the aid of the multiplier plunger and it is located there located casting metal in the mold cavity

injected. The casting metal is determined by the shape of the mold cavity different back pressure opposite. This different back pressure causes a uneven in its speed, jerk

like retraction of the plunger “Through this jerky retraction of the plunger causes the casting metal to mix with the air, which is still in the mold cavity at the time. There is a risk of gas opening

took through the cast metal “This gas uptake prevents the quenching and tempering of the aluminum die-cast parts produced in this way, · '·

The object of the present invention is to develop a die-casting process with which the plunger Moved smoothly into the casting metal chamber and thus mixing of the casting metal with the be in the press chamber and in the mold cavity

sensitive air is avoided.

This object is achieved in that in the press cylinder on the side of the plunger facing away from the multi-explorer flask, a defined

Back pressure is built up in the hydraulic medium. These measures can be in the press cylinder counter pressure counteracting the pressing pressure can be built up, which compensates for the different back pressure of the Cast metal intercepts in the mold cavity and so

causes the plunger to run smoothly. A back pressure control in a range of 0-140 bar has proven to be practical and sufficient. The level of the counter pressure is dependent on the wall thickness of the die-cast part to be cast.

Another object of the invention is to provide an apparatus with that in a die-cast plunger assembly of the type described above, a counter pressure in the plunger cylinder

can be built,

This problem is solved in that an outlet throttle is arranged in the outlet pipe "

By this measure, when retracting the

Hydraulic medium running off the press piston is opposed to a definable dynamic pressure. This dynamic pressure acts as a counter pressure on the side facing away from the multiplier piston of the plunger and catches any

Backlogs of the plunger rod.

For the embodiment of the invention it is provided that the outlet throttle by a "predeterminable Opening path within one, the drain pipe too

orderly throttle control is adjustable. These measures can be used to regulate the flow rate in the discharge throttle. The back pressure in the hydraulic medium, depending on the wall thickness of the die-cast to be cast

Partly controlled »For this purpose, the outlet throttle is assigned a throttle gap and the throttle gap can be controlled via the opening path of the flow throttle. One that is easy to manufacture Execution of the discharge throttle provides that the

Throttle gap is conical ring-shaped. .

A device according to the invention is shown in the enclosed Drawing shown and is described in more detail below, - it shows:

Fig. 1 ■ ·· the. Section through a die-cast plunger assembly with .Drain throttle in the drain pipe;

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30th

2 shows a detailed representation of the outlet throttle according to section "A" in FIG. 1.

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33-5453

The die-cast plunger assembly shown in FIG. 1 10 consists essentially of a press cylinder 12 in which a press piston 11 is arranged to be movable back and forth. The plunger 11 is guided on a plunger rod 13,

which in turn outside the press cylinder 12 as a press piston into a press chamber (not shown) is retractable.

The press cylinder 12 is on both sides of the press

piston 11 filled with hydraulic medium 16, which is from a multiplier piston 14 on the Pressing piston rod 13 facing away from the side can be pressed against the pressing piston 11. The multiplier flask 14 for its part is in a multiple

Katorylinders 15 arranged to be displaceable back and forth. When pressing the multiplier piston 14 runs the hydraulic medium 16 pressureless through a drain pipe 17 and a check valve 18 from.

After the injection process has ended, the pressure on the multiplier piston 14 is reduced and the hydraulic medium 16 through a return 22 and a return valve 19 back in the press cylinder 12 out. The plunger 11

is thereby reduced. To avoid Hydraulic shocks in the event of improper handling are, for example, a cone valve 20 on a flange bushing 21 is provided as a control for a return control 23.

In the detailed illustration shown in FIG

7 -

a discharge throttle 24 is in the discharge pipe 17 arranged, which is adjustable via an adjustable opening path 25 "The outlet throttle 24 has on their side facing the drain pipe a conical annular throttle gap 26 on over the the draining hydraulic medium 16 accumulates or through drainage openings 27 into the throttle drain 28 can be performed. The throttle gap 26 can easily through its conical ring-shaped design . and securely closed or, if necessary, can be set in a finely adjustable manner. The outlet throttle 24 is guided in a loss-free manner in a throttle guide 29 and via the opening path 25 mechanically or hydraulically movable.

15th

With the help of this throttle gap 26, a back pressure is built up in the drain pipe 17, which is a counter pressure transmits to the side of the plunger 11 facing away from the multiplier piston 14. This back pressure prevents a jerky retraction of the plunger 11 and thus a mixing of air with the pressed Cast metal.

The back pressure can be adjusted very finely via the outlet throttle 24 in a range of approximately 0-200, preferably from 0-140 bar can be regulated. The respectively required Back pressure depends on the wall thickness and the changes in wall thickness of the workpiece to be cast.

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Claims (1)

FICHTEL & SACHS AG, 8720 Schweinfurt Patent and utility model auxiliary application Die-casting process for the production of remunerative, high-strength die-cast parts through jerk-free Guide of the plunger and device for its implementation Expectations 1. Die-casting process with a die-cast plunger assembly in the case of a plunger cylinder, a plunger from a multiplier flask The casting chamber of a die casting machine is moved into 5. with the aid of hydraulic medium the hydraulic medium on the side facing away from the multiplier piston is passed without pressure via a drain pipe and a non-return valve, characterized in that that in the press cylinder on the multipli The side of the plunger facing away from the catheter piston creates a defined counter pressure in the hydraulic medium is built, j
2 «Die-cast piston arrangement in which, in a press piston cylinder, a press piston is retracted from a multiplier piston with the aid of hydraulic medium into the casting chamber of a die casting machine, the hydraulic medium on the one facing away from the multiplier piston Unpressurized string via a drain pipe and a Check valve is derived, characterized in that in the drain pipe (17) a Drain throttle (24) is arranged. , 3. Die-cast plunger assembly according to claim 2, characterized in that the outlet throttle C24) by a predeterminable _v opening path (25) associated within a, the discharge pipe (17) throttle guide (29) is adjustable " 4. Die-cast plunger assembly according to Proverbs 2 and 3, characterized in that the outlet throttle (24) is assigned a throttle gap (26) and the throttle gap (26) via the Opening travel (25) of the outlet throttle (24) is controllable. 5. Die-cast plunger assembly according to An-Proverbs 2 to 4, characterized in that the throttle gap (26) is cone-shaped.