AT521034B1 - Shaping machine with a hydraulic system - Google Patents

Abstract

Shaping machine, in particular injection molding machine, with a hydraulic system (1), wherein the hydraulic system (1) comprises an oil tank (2) for hydraulic oil and an opening into the oil tank (2) return (3) for hydraulic oil. In the return (3), a centrifugal separator (4) is provided for the back-flowing hydraulic oil before the confluence with the oil tank (2). The centrifugal separator (4) has two treated hydraulic oil outlets (5, 6), of which a first outlet (5) for a volume fraction of treated hydraulic oil with foreign matter having a lower specific gravity than the hydraulic oil and a second outlet (6) for a volume fraction of treated hydraulic oil is provided with foreign matters having a higher specific gravity than the hydraulic oil. The first outlet (5) opens into a first region (7) of the oil tank (2) and the second outlet (6) into a second region (8). The first and second outlets (5, 6) open into the oil tank (2) in such a way that there is no appreciable mixing of the volume fractions flowing into the chamber via the first outlet (5) and the second outlet (6).

Description

Description: [0001] The invention relates to a shaping machine having the features of the preamble of claim 1.

Today's designs of hydraulic systems work with filters that are installed in various places in the hydraulic system. These are to filter contaminants such as solids / particles, oil aging products and water.

A generic filter is apparent from US 2004/0099595 A1.

The placement of the filter in the hydraulic system results in that the entire volume flow of the hydraulic oil or only a part thereof is filtered, the volume flow of one or more (main) pumps can come or even from smaller (Neben- / filter) pumps. A distinction is made after the placement of the filter between suction filters, line filters and return filters. Characteristic here is that the volume flow, which is passed through the filter depends on the flow rate of the pump and the switching positions of the valves.

By "filter" in the present disclosure is meant elements based on a sieving action, such as e.g. B. cake filtration or depth filtration.

Disadvantages of the mentioned filters are:

[0007] Suction filter: cavitation tendency due to filter resistance, high power requirement [0008] Line filter: expensive due to the required high-pressure design, filter resistance over time and temperature greatly variable, high power requirement [0009] Return filter: filter resistance over time and temperature greatly variable, high power requirement In addition to such filters, centrifugal separators (in particular so-called hydrocyclones) are known, by means of which solid particles contained in liquids or gases can be separated or classified. It can also be separated emulsions, such as. B. oil-water mixtures. The inflowing medium flows tangentially in an upper region in the centrifugal separator, whereby the mixture is forced to a circular path. Due to the different densities of the substances, heavier proportions are forced outwards rather than lighter ones. The lighter parts then rise and exit the centrifugal separator through a first outlet, while heavier parts migrate downward due to gravity and exit the centrifugal separator through a second outlet.

The object of the invention is to provide a generic shaping machine, in which the problems discussed above are avoided.

This object is achieved by a shaping machine having the features of claim 1. Advantageous embodiments of the invention are defined in the dependent claims.

According to the invention, provision is made in the invention for at least one centrifugal separator for the hydraulic oil flowing back into the oil tank to be provided in the at least one return upstream of the inlet opening, the at least one centrifugal separator having at least two outlets for treated hydraulic oil, of which a first outlet for a volume fraction of treated hydraulic oil is provided, in which there are foreign substances with a lower specific gravity than the hydraulic oil and a second outlet for a volume fraction of treated hydraulic oil is provided in which foreign substances with a higher specific gravity than the hydraulic oil are / 9

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Patent Office - the first outlet opens into a first region of the at least one oil tank and the second outlet opens into a second region of the at least one oil tank - a pump is provided, through which hydraulic oil from the second region of the at least one oil tank can be conveyed to a filter.

The basic inventive idea in the invention is that:

- The volume fraction with foreign matter, which have a lower specific gravity than oil, can be introduced in the vicinity of a liquid level of the oil tank, which also causes outgassing of z. For example, the volume fraction with foreign substances, which have a higher specific density than oil, can be introduced so that it can be completely or at least predominantly sucked in by a pump which leads to a filter.

The invention has a number of advantages:

- All particles are concentrated in only a partial volume of the treated hydraulic oil, which can be filtered more effectively. This allows a better and more efficient filtration and / or a lower flow rate of the pump, which promotes the treated hydraulic oil to a filter.

The system according to the invention is very efficient, especially in the case of large particles, which would cause increased wear in components of the shaping machine and could lead to an immediate machine downtime.

- Gas bubbles reach faster the surface of at least one oil tank or the second oil tank.

It results in a lower pressure loss than when using conventional filters.

- A filter exchange (in the hydrocyclone) is not necessary.

Particles which come out of the system are separated immediately.

With respect to the centrifugal separator (preferably a hydrocyclone), this may be designed per se as described above in the prior art. In addition, an electro-magnetic field applied in the hydrocyclone may assist gravity-induced separation or conditioning. The hydrocyclone may have fixed or rotating outer walls which are driven mechanically or by flow forces.

In one embodiment of the invention it is provided that the at least one oil tank has at least a first and a second fluidly separated chamber and the first outlet opens into the first chamber and the second outlet opens into the second chamber, wherein the fluidic separation at least to such an extent that a transfer of foreign substances with a greater specific density than hydraulic oil is avoided.

Alternatively, in one embodiment of the invention, it may be provided that the at least one oil tank has a chamber into which the first outlet and the second outlet open, wherein the first outlet and the second outlet are arranged such that they are of no appreciable value Mixing of the flowing over the first outlet and the second outlet into the chamber volume fractions comes.

In one embodiment of the invention, at least two returns are provided for hydraulic oil, wherein the at least two returns flow into a pre-chamber, of which a return, in which the centrifugal separator is arranged, leads to at least one oil tank, wherein it is preferably provided that the prechamber has a smaller volume than the at least one oil tank.

In the invention, the prechamber may be closed or open. With

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In the invention it can be provided that the volume fraction of treated hydraulic oil, in which foreign substances are located with a lower specific gravity than the hydraulic oil, via a flow through a pump to a filter and / or a cooler can be fed. It can be provided that the filtered and / or cooled oil in the at least one oil tank or a separate oil chamber can be conveyed. If the delivery into the at least one oil tank, a fluidic separation should be provided by which at least the passage of foreign matter with a greater specific gravity is avoided as hydraulic oil.

In a preferred embodiment of the invention, especially if only one oil tank or separate chambers are provided, components for flow calming and deflection (eg, diffusers) are provided in the region of the inlet openings. These ensure a laminar inflow into the oil tank.

Filtered and optionally cooled hydraulic oil can be promoted by at least one as a pump via at least one flow to be supplied to the components of the molding machine, which are in communication with the return lines of the hydraulic system. Embodiments of the invention will be discussed with reference to the figures. In the drawings: Fig. 1 shows a first embodiment of the invention; Fig. 2 shows a second embodiment not according to the invention; Fig. 3 shows a third embodiment of the invention; Fig. 4 shows a block diagram of a first hydraulic system according to Figs Invention Fig. 5 is a block diagram of a second hydraulic system according to the invention. The components shown in the figures in a certain number may, of course, also be provided in a different number.

Fig. 1 shows a detail of an embodiment of a hydraulic system 1 of a molding machine, in particular injection molding machine, according to the invention.

Evident is an oil tank 2 for hydraulic oil, which is connected via two inlet openings with a first outlet 5 and a second outlet 6 of a centrifugal separator 4 (see Fig. 4). The first outlet 5 conveys a volume fraction of treated hydraulic oil in which foreign matters having a lower specific gravity than the hydraulic oil are. The second outlet 6 conveys a volume fraction of treated hydraulic oil in which foreign matters having a higher specific gravity than the hydraulic oil are.

The first outlet 5 opens into a first region 7 of the oil tank 2. The second outlet 6 opens into a second region 8 of the oil tank 2. These areas 7, 8 are separated by barriers into two chambers 11, 12, the area 7 being formed by the chamber 11 and the area 8 by the chamber 12. An outlet of the oil tank 2 leads to a further chamber 12 ', which is here outside of the oil tank 2, but could also be arranged in this. This further chamber 12 'serves to provide hydraulic oil treated by the centrifugal separator 4 for a pump 9 (see Fig. 4), but is not absolutely necessary.

Fig. 2 shows a detail of another embodiment of a hydraulic system 1 of a molding machine, in particular injection molding machine. In contrast to the embodiment of FIG. 1, two separate oil tanks 2, 2 'are provided and the first outlet 5 of the centrifugal separator 4 opens into the first oil tank 2 and the second outlet 6 of the centrifugal separator 4 opens into the first oil tank 2'. An outlet of the oil tank 2 and an outlet of the oil tank 2 'each lead to a further chamber 12', which here outside the

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Oil tanks 2, 2 'is located. This further chamber 12 'serves to provide hydraulic oil treated by the centrifugal separator 4 for a pump 9 (see Fig. 4), but is not absolutely necessary.

Fig. 3 shows a variant of Fig. 1, wherein components for flow calming and deflection 16 (eg diffusers) are additionally provided here. These ensure that there is no appreciable mixing of the volumes flowing through the first outlet 6 and the second outlet 7 into the chamber of the oil tank 2, although no barriers are provided within the oil tank 2. The components for flow calming and steering 16 ensure a laminar inflow of the hydraulic oil into the oil tank 2 and a mixing of the hydraulic oil flowing into the oil tank 2 via the outlets 5, 6 of the centrifugal separator 4 is prevented.

Fig. 4 shows a hydraulic system 1 of a molding machine, in particular injection molding machine, according to the invention.

Recognizable are several returns 3 (four examples here, but there may be any number), of which three returns 3 open into an antechamber 13, of which a return 3, in which the centrifugal 4 is arranged to the oil tank. 2 leads. The pre-chamber 13 preferably has a smaller volume than the oil tank 2. The pre-chamber 13 collects the hydraulic oil of the returns 3 and ensures a more uniform flow through the centrifugal separator 4.

The oil tank 2 here has a plurality of chambers 11, 12, 12 '(for example, four are shown), as shown in Fig. 1. Hydraulic oil can be delivered from the second chamber 12 of the oil tank 2 to a filter 10 and then to a cooler 15 via a pump 9. The filtered and cooled hydraulic oil is supplied to a chamber 12 'which communicates fluidically with a first chamber 11. Hydraulic oil can be provided from a further chamber 12 'by means of a pump 9 functioning as the main pump (several pumps 9 can, of course, also be provided) via a supply line 14 (unlike that shown, of course, any number of supply lines 14 can be provided) to the components 17 to be supplied the forming machine to be promoted, which are associated with the returns 3.

In the variant of FIG. 5, no antechamber 13 is provided. By way of example, only one return 3 is shown here, of course several return flows 3 can be provided.

1 to 3 it can be noted that the connection shown in Figs. 4 and 5 can be made to a pump 9 and then a filter 10 in the lower portion of the area 8 or the chamber 12.

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LIST OF REFERENCE NUMBERS:

2, 2 '

11

12.12 '

17

2, 2 '

11

12.12 '

17

hydraulic system

oil tank

returns

Centrifugal separator first outlet of the centrifugal separator second outlet of the centrifugal separator first area of the oil tank second area of the oil tank

pump

Filter first chamber of the oil tank second, third chamber of the oil tank

antechamber

leader

cooler

Component for flow calming and steering components to be supplied

Claims (6)

claims 1. Forming machine, in particular injection molding machine, with a hydraulic system (1), wherein the hydraulic system (1) comprises: - At least one oil tank (2) for hydraulic oil - At least one connected via an inlet opening with the oil tank (2) return line (3) for hydraulic oil, wherein - In the at least one return (3) in front of the inlet opening in the at least one oil tank (2) at least one centrifugal separator (4) for the in the oil tank (2) flowing back hydraulic oil is provided - The at least one centrifugal separator (4) at least two outlets (5, 6) for treated hydraulic oil, of which a first outlet (5) is provided for a volume fraction of treated hydraulic oil, in which are foreign substances having a lower specific gravity than the hydraulic oil and a second outlet (6) is provided for a volume fraction of treated hydraulic oil in which there are foreign substances having a higher specific gravity than the hydraulic oil - The first outlet (5) in a first region (7) of the at least one oil tank (2) opens and the second outlet (6) opens into a second region (8) of the at least one oil tank (2) a pump (9) is provided, by means of which hydraulic oil from the second region (8) of the at least one oil tank (2) can be conveyed to a filter (10), characterized in that the at least one oil tank (2) has a chamber, in which the first outlet (5) and the second outlet (6) open, wherein the first outlet (5) and the second outlet (6) are arranged so that there is no significant mixing of the first outlet (5) and the second outlet (6) in the chamber flowing volume fractions comes. 2. A molding machine according to claim 1, wherein the at least one oil tank (2) at least a first and a second fluidically separated chamber (11, 12) and the first outlet (5) opens into the first chamber (11) and the second outlet (6) opens into the second chamber (12), wherein the fluidic separation is given at least to such an extent that a transfer of foreign matter with a greater specific gravity than hydraulic oil is avoided. 3. Forming machine according to at least one of claims 1 or 2, wherein at least two return lines (3) are provided for hydraulic oil and the at least two returns (3) in an antechamber (13) open, of which a return (3), in which the Centrifugal separator (4) is arranged, leading to at least one oil tank (2), wherein it is preferably provided that the pre-chamber (13) has a smaller volume than the at least one oil tank (2). 4. Forming machine according to at least one of the preceding claims, wherein the centrifugal separator (4) is designed as a hydrocyclone. 5. A molding machine according to at least one of the preceding claims, wherein the volume fraction of treated hydraulic oil in which there are foreign substances with a lower specific gravity than the hydraulic oil, via a flow (14) by a pump (9) a filter (10) and / / or a cooler (15) can be fed. A forming machine according to claim 5, wherein the filtered and / or cooled oil is conveyable into the at least one oil tank (2) or a separate oil chamber.