DD155734A1 - METHOD AND HYDRAULIC CIRCUIT ARRANGEMENT FOR CURING CYCLE TIME IN PROCESSING MACHINES, IN PARTICULAR INJECTION CASTING MACHINES - Google Patents

Abstract

The field of application of the invention relates to processing machines with hydraulic drive, in particular injection molding machines with hydromotor plasticizing drive. The aim of the invention is to reduce the technical-oeconomic effort in hydraulic control of injection molding machines with a hydraulic motor as a plasticizing and to increase the Arbeitproduktivitaet, which task by Gewaehrleistung a universal use of the system, by expanding the storage operation and an associated shortening of Total cycle time is to be achieved. The solution is that when variable displacement pumps are used, during times when the pump drive is bound by a parallel operation, the pressure fluid reservoir takes over complete operations or when using fixed displacement pumps, if not all the pumping capacity is required for the purging process remaining pump capacity is used for the realization of other operations with or without the aid of the pressure fluid storage.

Description

Schwerin, the 03. 02. 1981

22 6597

Title of the invention

Method and hydraulic circuit arrangement for shortening the cycle time in processing machines, in particular injection molding machines

field of use

The field of application of the invention relates to processing machines, in particular injection molding machines with hydromotoric plastication drive.

Characteristic of the known technical solutions

Injection molding machines are known which have low-noise hydraulic motors as the plating drive and which can take up the entire pump delivery flow during the plasticizing phase. In this case, with the help of the pump no parallel operation, such as the opening movement of the tool carrier for the purpose of molding removal, carried out so that in the worst case, the plasticizing time causes an extension of the necessary cycle time. In the conventional injection molding machines, a cycle time extension must be accepted when processing very temperature-sensitive thermoplastics. By extending the pump capacity, this cycle time extension can be counteracted. This inevitably results in disadvantages such as greater space requirements, an increase in the overall sound power level of the system, poor utilization of the entire pump drive and increased costs due to the complex control *

It is known from DE-OS 2,500,635 a hydraulic device, are provided in the means for realizing an energy storage. In detail, a first distributor ,, is arranged with two positions in the discharge line of the auxiliary pump, wherein a compound of this auxiliary pump in its first position to the pressure collector and in its second position to a container and that between this first distributor

, and a branch is branched off from the pressure accumulator communicating with a supply line of the collecting device. These

  Line is provided with a second distributor with two positions, which ensures the closing in its first position and the opening of this line in its second position. there

, a liquid pressure indicating device is arranged in the supply line of the collecting device and controls the selection of the positions of the first and the second distributor by interposition of a logic device. Furthermore, from DE-OS 2c5O2.672 a hydraulic device is known, are also provided in the means for realizing an energy storage. In a hydraulic working circuit, a second directional valve is connected in the pressure line between the pump and the first directional control valve.

  orders, which interrupts the pressure line in its first switching position and connects the pump with a first auxiliary line, which opens into a pressure fluid reservoir and which releases the pressure line in its second switching position. On the first auxiliary line, a third two-way valve is arranged, connected in the first switching position of the hydraulic accumulator to a second auxiliary line and the first auxiliary line is interrupted. In the second switching position, the first auxiliary line is open and indeed at shut-off of the pressure accumulator from the second auxiliary line. The hydraulic working group is assigned a logic control unit which controls the second and the third two-way valve in dependence on the input values. , '

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The two aforementioned solutions would, in the case of use in injection molding machines increased technical-economic effort to PoIge · They are only to cover very large oil flow demand for a short period or for pressure control functions suitable to keep the pump capacity small.

The entire working cycle of an injection molding machine could not be significantly shortened by such circuit arrangements.

Object of the invention

The aim of the invention is to reduce the technical-economic effort in hydraulic controls of injection molding machines with a hydraulic motor as Piastizierantrieb and to increase the labor productivity of the system ·

Explanation of the invention of the invention

The object of the invention is to provide for processing machines, in particular injection molding machines, where the Piastizierantrieb a hydraulic motor, to provide a hydraulic control that ensures a universal application of the system and the total cycle time is shortened by an extension of the memory operation.

According to the invention the object is achieved in that when using variable displacement pumps during the cycle time, when the pump drive is bound by intersecting operations, ie, if the Piastizierantrieb for technological reasons beyond the cooling time also acts, known per se electronic control in dependence such preprogrammed values in such logical decisions that one or more hydraulic fluid storage, hereinafter referred to as pressure fluid storage, during the plasticizing alone the

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When using constant displacement pumps, the electronic control makes logical decisions such that during the cycle time, in which the pump delivery flow is only partially bound by the plastication drive, the remaining pump delivery flow is used to drive the tool-side consumers with or without the aid of the pressure fluid reservoir, without causing the intersecting with these operations intersecting plasticizing ·

In the hydraulic circuit arrangement for carrying out this method, the pump and the hydraulic accumulator are connected in dependence on stored in the electronic control data via a valve combination with the consumers "The electronic control is provided with a target value specification and a level control device with the pressure fluid reservoir and connected directly to the pump ·

The hydraulic working circuit is characterized in detail by an outgoing directly from the pump line branch, which is associated with a pressure relief valve · This line branch is in turn connected via two independently operating directional control valves, each with a further line branch, one of these latter line branches a direct connection between an oil reservoir and the hydraulic accumulator is simultaneously connected via one or more flow control valves and a directional control valve connected behind it with a further separate line branch · At this last-mentioned line branch one consumer is connected via three further directional control valves and another consumer is directly connected via a V / egeventil and a line connected to the pump ·

When using variable displacement pumps, an electrically controllable displacement adjustment is preferably provided, which is arranged directly on the pump.

Furthermore, it is advantageously provided that the valve combination is installed on or in a hydraulic block.

22 6 597

embodiment

The invention will be explained in more detail below using an exemplary embodiment. The embodiment shown in the drawing shows:

Pig. 1: A schematic representation of the link

electronic control with elements of hydraulic working group.

Pig. 2: A detailed schematic representation of the

hydraulic circuit arrangement.

Figures 1 and 2 show the application of the method according to the invention in an injection molding machine with a hydraulic Piastizierantrieb »

Figure 1 shows in detail that the pump 1 and the hydraulic fluid reservoir 2 are connected via the valve combination 3 with the end consumers 4 »5, wherein the electronic control 22, the order and the time course of the operations by processing the in the target value specification 23 controls and moreover makes logical decisions to secure the cycle time.

One or more hydraulic fluid reservoirs (2.2 ^f 2 ^{! L} ) can be arranged in the hydraulic circuit, wherein only one hydraulic fluid reservoir 2 is referred to below. The arrangement of the valve combination 3 within the circuit arrangement for carrying out the method is shown in FIG. Thereafter, the hydraulic circuit consists of a line branch 9, which is associated with a pressure relief valve 10. This line branch 9 is connected via directional control valves 11, 12 with two further line branches 13, 14, wherein via the line branch 13, a direct connection between an oil reservoir 8 and the pressure fluid reservoir 2 and via one or more flow control valves 15 * 15 'and a downstream switched Yifegeventil 16 is a connection from the pressure fluid reservoir 2 to the line branch 14. On Leitungezweig 14 turn

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are connected via directional control valves 17,18,19 each consumer 4,6,7 connected. The consumer 5 is only directly connected via the directional control valve 12 and the line 20 to the pump 1. The mode of action is as follows:

According to FIGS. 1 and 2, the electronic control unit 22 controls the valve combination 3 in connection with the pump 1, the pressure accumulator 2 and the end consumers 4, 5, 6, 7 as follows on the basis of the data stored in the setpoint value specification 2-3: By means of the setpoint value specification 23, the electronic control unit 22 determines the order and the chronological course of the operations and also makes logical decisions for securing the cycle time the electronic control 22 switches the valve combination 3 so that energy is stored in dependence on the level control device 21 of the hydraulic fluid store 2 during work-related downtime and at load of the pump 1 for the operation of the consumer 5 of the hydraulic accumulator 2 in parallel the consumers 4, 6, 7 drives As a pump drive are preferably variable displacement, for which preferably an electrically controllable displacement adjustment is vprgesehen ^ is used, but also one or more constant pumps are conceivable. When using multiple fixed displacement pumps, the electronic control 22 can control the valve combination 3 such that whenever the entire pump capacity is not required for the operation of the consumer 5, the remaining pump capacity for realizing the working movement of the consumer 4, 6, 7 with or without Help the pressure fluid reservoir 2 is used. Referring to the operation of an injection molding machine, the following operation is possible:

The pump 1 realizes a compl. Tool closing movement including the nozzle operation. The closing force is built up low noise by the accumulator pressure on one or more high pressure cylinder, for example, by the consumer 4, 6, 7, is transmitted. After reaching.

- 7 -.

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the necessary closing and Düsenanpreßkräfte the plasticized material is injected by the pump 1 with or without support of the hydraulic fluid reservoir 2. Upon completion of the mold filling, the holding pressure switches on and the holding pressure time expires. The holding pressure can be maintained by the accumulator 2 in the interest of reducing the noise. During the holding time the accumulator 2 is charged. If the accumulation time has elapsed, the cooling time begins After the cooling time has elapsed, when the plasticizing has been completed, a complete tool opening movement is realized by means of the pump 1 or, if the plasticizing takes place parallel to the planned tool opening, this complete tool opening movement with the help of the hydraulic fluid reservoir The necessary charging of the pressure fluid reservoir 2 then takes place during the time of partial removal, ie after the end of a working cycle nd opening of the movable tool carrier, when next to the pump 1, the hydraulic fluid reservoir 2 is taken to help. This leads to an increase in the dry-running number. The hydraulic control according to the invention also allows a delay of the plasticizing. until the next following cycle, so that in this case the complete closing movement can be realized by the hydraulic fluid storage 2 · Thus, the processing of very temperature-sensitive material such as PVC is possible · The circuit connection of the consumer 4, 6, 7, 5 with the pressure fluid reservoir second and / or the pump 1, follows in detail according to the vorbeschr.iebe.nen type according to Figure 2 as follows:.

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" ⁸ " 22 6 59 7 ·

The pump 1 sucks the operating fluid from an oil tank 8 and delivers it to the line branch 9. The operating pressure of the pump 1 is controlled by a pressure limiting valve 10. The line branch 9, shown in dashed lines, is connected to the line branch 13 via the valves 11, 12. shown with dash-dot line, and 14, connected with dash-dot-dot line, connected * '

At the line branch 13 of the hydraulic accumulator 2 is connected. The determination of determinate flow rates from the line branch 13 via one or more flow control valves 15,15 'and the directional control valve 16, which allows connection to the line branch 14. The consumer 4> 7> 6 is connected to the line branch 14 via the valves 17, 18, 19 »The consumer 5 is driven only by the pump 1 via the line branch 9, the operated directional control valve 12 and the line 20 · In the basic position promotes the pump 1 in non-pressurized circulation or loads in drain-related downtime the pressure fluid reservoir 2 by the pressure relief valve realizes the necessary operating pressure and the directional control valve 11 is actuated. The charging process is terminated only when a level control device 21 indicates the filling. The consumers 4, 7 and 6 are supplied via the directional control valves 17,18 and 19 from the line system 14, wherein the switching position of the directional control valves 12 and 16 decides whether the consumer 4, 7 »6 by the pump 1 or the hydraulic fluid reservoir or through the Pump 1 and. the pressure fluid reservoir 2 are driven. The decision is made by the electronic controller 22. The workflow according to the invention has the following advantages:

- The max. Pump capacity corresponds to the consumer 5

- little need for space

- simple pipe system

~ Universal An.triebsmöglichkeit the consumer 4, 7, β

- low noise level

- Increase the labor productivity of the plant

- higher capacity utilization of the pump 1

Claims (2)

Invention claim (1) is connected · 5 · Hydraulic circuit arrangement for carrying out the method according to item 1, characterized in that when using variable displacement pumps, preferably an electrically controllable displacement adjustment is provided, which is arranged directly on the pump (1). 6 · Hydraulic circuit arrangement for carrying out the Ver. according to item 1-4, characterized in that the valve combination (3) is installed on or in a Hydräulikblock. A method for shortening the cycle time in processing machines, in particular injection molding machines with a hydraulic Piastizierantrieb, in which a motor drives at least one pump, which is optionally connected to a pressure fluid reservoir or a consumer and the pressure fluid reservoir outputs as needed to support the pressure generator, its stored energy, which is recharged in dead times, characterized in that when using variable displacement pumps during the cycle time, when the pump drive is bound by 'intersecting' operations and the Piastizierantrieb (5) for technological reasons beyond the cooling time acts, a per se known electronic Control (22) in response to programmed therein values such logical decisions that the one or more hydraulic fluid storage (2.2 ^f 2 ") during the plastication alone the tool-side consumers (4,6,7) betr eibt without interrupting the intersecting with these operations Piastiziervorgang is interrupted. 2. Procedure after fu'nkt. -j _f characterized in that logical decisions are made in such a way in the use of fixed displacement pumps in electronic .Control (22), that only partially through the Piastizierantrieb (5) is attached during the cycle time in which the Pumpenfö'rderstrom, the remaining Pumpenfö ' flow for driving the tool-side consumers (4,6,7) with or without the aid of or the pressure fluid reservoir (2.2 ^f 2 ") is used without interrupting the overlapping with these operations Piastiziervorgang. ~ ⁱ⁰ ~ 22 6 597 3. Hydraulic circuit arrangement for carrying out the method according to item 1, characterized in that the pump (1) and the or the pressure fluid reservoir (2.2 * 2 ") via the valve combination (3) in dependence on in the electro- nischer control (22) data with the consumers (4,5j6,7) are in communication, wherein the electronic controller (22) is provided with a desired value default (23) and via a level control device (21) with the or the hydraulic fluid reservoirs (2.2 ^f 2 ") and is connected directly to the pump (1). 4. Hydraulic circuit arrangement for carrying out the method according to item 1-3, characterized in that the from the pump (1) outgoing line branch (9) is associated with a pressure relief valve (10) and this line branch (9) via way valves (11,12) is connected to further line branches (13,14), via the line branch (13) has a direct connection between an oil reservoir (8) and .dem or the hydraulic fluid store (2,2'2 ") consists, and one or more flow control valves ( 15,15 ') and a directional control valve (16) connected behind it a connection from the one or more hydraulic fluid reservoirs (2,2'2 ⁿ ) to the line branch (14), from where via the directional control valves (-17,18,19) consumers (4,6,7) are connected and the consumer (5) via the directional control valve (12) and the line (20) directly to the pump 2 ... Seta