DE102019220133A1 - Hydraulic casting unit - Google Patents

Abstract

A casting unit is disclosed, the casting cylinder of which can be moved regeneratively via a flow control valve in a pre-filling phase. A boosting unit, for example a pressure booster or a high-pressure accumulator, is also switched on via this flow control valve in a holding pressure phase.

Description

The invention relates to a hydraulic casting unit according to the preamble of claim 1.

The basic structure of such casting units, which are used in primary molding machines, such as injection molding, die casting or thixomolding machines, is for example in the document going back to the applicant DE 10 2017 220 832 A1 disclosed. Accordingly, the casting unit has a double-acting casting cylinder, the piston of which delimits a bottom space on the piston crown side and the end face of which on the piston rod side delimits an annular space. In the known solution, the floor space is initially connected to a low-pressure accumulator during a pre-filling and a mold filling phase via a 2/2-way seated valve designed as active logic, for example, the annular space of the casting cylinder being connected to the floor space via a control valve so that in a pre-filling phase Pressure medium displaced from the shrinking annular space is fed to the expanding floor space via the said control valve in a regenerative circuit. In a mold filling phase, a pressure medium connection to the tank can be opened for the shot via a tank-side control valve and the control valve between the piston chamber and the annular chamber can be closed. In a holding pressure phase, the floor space is then connected to a high pressure accumulator via a further control valve, the pressure medium connection to the low pressure accumulator being shut off via the active logic. In this holding pressure phase, the aforementioned tank-side control valve, a pressure medium connection between the annular space and the tank, remains open, so that the melt in the cavity is compressed at high pressure and any material loss is compensated for.

The basic structure of the active logic used in this casting unit is taken from the document DE 10 2005 035 170 B4 known.

With one in the pamphlet DE 10 2017 221 500 A1 disclosed casting unit, no regenerative circuit is provided. In the pre-filling and mold filling phase, the bottom space is acted upon by a low-pressure accumulator via the active logic and an outlet-side control valve is opened so that the piston of the casting cylinder extends at a predetermined speed. In the transition from the pre-filling phase to the mold filling phase, this outlet-side valve is opened further so that the piston accelerates and moves out at a relatively high speed. The pressure medium displaced from the shrinking annular space flows through the outlet-side control valve to a drain reservoir and then, when a predetermined pressure is reached in the drain reservoir, through a check valve or a diaphragm out to the tank. This reduces the maximum volume flow to the tank and the associated turbulence.

After the completion of the pre-filling phase, the pressure intensifier (multiplier cylinder) is accelerated to initiate the holding pressure phase and an increased pressure is built up in the floor space. The pressure booster is accelerated by connecting its annular space to the low-pressure accumulator or tank via a control valve.

In contrast, the invention is based on the object of creating a casting unit which enables an optimized casting process with little outlay in terms of device technology.

This object is achieved by a casting unit with the features of claim 1.

Advantageous further developments of the invention are the subject of the subclaims.

The hydraulic casting unit according to the invention, which is preferably designed for use in an injection molding, die casting or thixomolding machine, has a casting cylinder designed as a differential cylinder, the piston of which delimits a bottom space on the bottom and an annular space on the piston rod side. The casting unit also has a control valve which is designed to connect the annular space to the floor space in a pre-filling and / or mold filling phase in the manner of a regenerative circuit. The casting unit also has a drain valve for connecting a tank line connected to the annular space to a tank during the mold filling phase and the holding pressure phase. According to the invention, a low-pressure source, which can be connected to the floor space via a shut-off valve device (low-pressure valve), and a hydraulic amplification unit are also provided, which is designed to support the extension movement of the casting cylinder in a holding pressure phase. According to the invention, the control valve is designed as a multi-way flow control valve - hereinafter referred to as flow control valve - with a closed position, wherein a valve slide of the flow control valve is designed to open the pressure medium connection between the floor space and the annular space in a first adjustment direction in the manner of the regenerative circuit described above and in a second Adjustment direction to activate the amplification unit. In the case of pressure regulation, pressure medium can preferably also be discharged from the floor space via the flow control valve.

With such a circuit, the basic functions (pre-filling phase regenerative, form filling and holding pressure phase) only two control valves (the flow control valve described above and the flow control valve in the drain) are required, so that the device-related expense is significantly reduced compared to conventional solutions. The flow control valve, which enables the regenerative process of the casting cylinder, allows the use of a smaller accumulator, whereby, due to the lower pressure difference across the flow control valve in the regenerative function, there is less cavitation and less wear and the process of the casting cylinder takes place at low speed with increased accuracy.

The pressure build-up and the pressure decrease in the holding pressure phase take place essentially via the flow control valve and the amplification unit, so that the concept according to the invention creates a significant system improvement.

In one embodiment of the invention, the amplification unit is formed by a high pressure accumulator which is connected to the floor space via the flow control valve in the second adjustment direction, so that the piston of the casting cylinder is acted upon by the high pressure in the extension direction. The second adjustment direction enables the regenerative switching as well as the pressure reduction in the holding pressure control.

In an alternative solution, the booster unit is designed as a pressure intensifier (multiplier), the pressure intensifier piston of which delimits a pressure intensifier annulus and a pressure intensifier pressure chamber, which can be connected to the low-pressure accumulator for acceleration via a shut-off valve or the like. The pressure medium connection of the pressure booster annulus to the tank line can be opened via the flow control valve in the second adjustment direction.

The flow control valve can be designed, for example, as an electrohydraulically piloted 3-way flow control valve.

In a variant of the invention, the shut-off valve device is designed as a 2/2-way active logic with a pilot valve. The active logic makes it possible to shut off or open the pressure medium connection between the low pressure accumulator and the bottom space of the casting cylinder and to control it very quickly when the pressure is built up in phase III, so that the mold filling phase can be completed very quickly and precisely.

In an alternative solution, instead of the active logic, the shut-off valve device is designed with a shut-off valve arranged downstream of the low-pressure source, a check valve being arranged between this and the bottom space of the casting cylinder. The shut-off valve closes and opens the connection to the casting cylinder. The check valve closes the connection when the pressure builds up in phase III.

According to an advantageous development of the invention, the pressure in the floor space can be reduced to the tank T via a switching valve.

The drain valve can be designed as an electrohydraulically piloted 2-flow control valve. The sequence control can also take place via other components, for example via a valve that can be adjusted by means of a servo motor.

To pretension and charge the low-pressure and / or high-pressure accumulator, the casting unit according to the invention is designed with a hydraulic pump, which can be designed as a variable displacement pump or as a fixed displacement pump with a servo motor and servo converter, or as a variable displacement pump with a three-phase motor and frequency converter, or as a variable displacement pump with a three-phase motor.

To avoid a start-up jolt when initiating the pre-filling phase, the casting unit according to the invention can also be designed with a device for pretensioning the piston and ring side of the casting cylinder and / or the pressure booster. The smooth initiation of the movement can also be controlled via an inflow-side continuous valve or a shut-off valve and a downstream diaphragm or via the pump.

For this purpose, for example, a preloading valve can be used, via which a pressure connection of the pump can be connected to the annular space of the casting cylinder or the pressure booster annular space for preloading. The pre-tensioning can also only take place by suitable control of the pump. This can also be used to load the memory.

In one embodiment of the invention, the bottom-side pressure chamber of the pressure booster can be connected directly to the tank or the pressure connection of the pump via two switching valves, for example designed as seat valves.

• 1 ein Prinzipdarstellung einer Gießeinheit;
• 2 einen vereinfachten Hydraulikschaltplan eines ersten Ausführungsbeispiels;
• 3 einen Hydraulikschaltplan einer Variante des Ausführungsbeispiels gemäß 2 und
• 4 einen Hydraulikschaltplan einer weiteren Variante des Ausführungsbeispiels gemäß 2.

Preferred exemplary embodiments of the invention are explained in more detail below with reference to schematic drawings. Show it:

• 1 a schematic diagram of a casting unit;
• 2 a simplified hydraulic circuit diagram of a first embodiment;
• 3 a hydraulic circuit diagram of a variant of the embodiment according to 2 and
• 4th a hydraulic circuit diagram of a further variant of the embodiment according to 2 .

In 1 are essential mechanical components of a hydraulic casting unit according to the invention 1 a die casting machine shown.

Accordingly, has a casting unit 1 a casting cylinder 10 , which is designed as a differential cylinder and its piston 11 accordingly with a piston rod 12th is executed. The piston 11 limited together with a housing 13th of the casting cylinder a floor space on the bottom 14th and one from the piston rod 12th interspersed annulus 15th . On the one from the case 13th cantilevered end portion of the piston rod 12th is a pouring piston 16 attached to a firing chamber 18th a pouring can 17th immersed. There is a filling opening in this 19th for the liquid or pasty molding compound, hereinafter referred to as the melt, of which the workpiece to be molded is to be made. The watering can 17th is attached to a form 20th attached, which usually consists of a movable and a fixed mold half. The two mold halves delimit a mold cavity 21 , also called a cavity, which is designed according to the geometry of the workpiece to be formed. The firing chamber 18th opens via a pouring channel 22nd into the mold cavity 21 a.

Such a casting unit 1 serves to bring the melt into the mold 20th , whereby, due to the rapid solidification process for the filling, high speeds and subsequently high pressures to completely fill the mold 20th and are required to compact and compensate for the shrinkage of the material during solidification.

With an in 2 illustrated embodiment of the invention is the casting cylinder 10 a pressure intensifier as a reinforcement unit 24 - also called multiplier cylinder - assigned, which is designed, for example, as a differential cylinder. A primary piston 26th delimits a pressure intensifier pressure chamber with a floor area 28 and a piston rod 30th penetrates a pressure intensifier annulus 32 . The structure of such pressure intensifiers 24 is known, so that further explanations are unnecessary.

The pressure medium supply of the casting unit shown 1 takes place via a hydraulic pump 34 , which is designed in the illustrated embodiment as a fixed displacement pump and a speed-controlled electric motor 36 is driven, which is designed, for example, as a servo motor with servo converter or as a three-phase motor with frequency converter. Their pressure connection is via a pump line 40 and a shut-off valve designed as a 2/2-way valve arranged therein 42 with the floor space 14th connected. The shut-off valve 42 blocks the pressure medium connection between the hydraulic pump in its illustrated spring-loaded basic position 34 and the floor space 14th and can be switched to a through position by means of a switching magnet.

The annulus 15th of the casting cylinder 10 is over a line 44 connected to a tank T, in which a drain valve 46 is arranged. In the illustrated embodiment, this is designed as an electro-hydraulically piloted 2/2 flow control valve, which in its basic position blocks the pressure medium connection to the tank T and, by activating the electrohydraulic pilot control, opens the opening cross-section to the tank T depending on a control signal.

The administration 44 and the pump line 40 are via a shut-off valve designed as a 2/2-way valve 48 connected that in a bias line 50 is arranged. This is in a spring-loaded basic position of the preload valve 48 shut off and can be activated by activating a switching solenoid of the shut-off valve 48 open up. By suitably controlling the valve 48 can also be the casting cylinder 10 be pulled back.

The pressure at the outlet of the hydraulic pump 34 is in a manner known per se via a pressure relief valve that opens to tank T. 52 limited.

According to the pressure intensifier 24 and the casting cylinder 10 a flow control valve 54 assigned, which in the illustrated embodiment is designed as a continuously adjustable, electrohydraulically piloted built-in control valve with three connections (3-way flow control valve). This has a connection 1 , a port 2 and a port 3.

The flow control valve 54 has a position in which the pressure medium connection between the connections 1 , 2 and 3 is closed. The control slide of the flow control valve can be controlled accordingly 54 in the sense of opening the pressure medium connection between the connection 1 and connection 3 can be adjusted. With the appropriate control, the pressure medium connection from port 2 to port 3 can be opened (see 2 ).

In the exemplary embodiment shown, the connection 2 is via a line 56 with the pressure intensifier annulus 32 connected. In one located downstream of the shut-off valve 42 extending line section 41 opens a pressure line 58 one, which is led to a port B of a pilot-operated 2/2-way built-in seat valve, which is used as an active logic 60 is executed. The pilot control takes place via a pilot valve 62 , which is designed as a 4/2-way valve. An input terminal A of the active logic 60 is via a low pressure accumulator line 64 with a low pressure accumulator 66 connected. The active logic 60 can also be mounted the other way around with regard to ports A, B.

A possible structure of the active logic 60 is from the publications cited in the introduction to the description DE 10 2017 220 832 A1 and DE 10 2005 035 170 B4 known, so that only the components essential for understanding the invention are explained here and reference is otherwise made to this prior art. Accordingly, this has active logic 60 a stepped main piston 70 , which with the pressure from the low pressure accumulator ND on the surface A5 against a valve seat 68 is biased and the pressure medium connection between the ports A, B and thus between the low-pressure accumulator line 64 and the pressure line 58 shut off. The active logic 60 can, for example, also be designed with two control surfaces and pressure compensation as well as with a switching pilot valve (see publication DE 10 2017 220 832 A1 and patent DE 10 2005 035 170 B4 ).

A tank line 84 is to a tank connection of the pilot valve 62 and an input port of the pilot valve 62 is over a line 88 to a pressure accumulator 90 connected to a higher pressure than the low pressure accumulator 66 is charged. By energizing a switching magnet of the pilot valve 62 this can be adjusted against the force of a spring into the switching position in which a ring control chamber of the active logic 60 with the memory 90 is connected, so that due to the higher pressure acting on the ring face A4 in the memory 90 the main piston 70 from the seat 68 lifts and the fluid connection between ports A, B opens. In the above-mentioned alternative execution of the active logic 60 with two control surfaces, a higher control pressure does not necessarily have to be provided.

Alternatively, the ring end face A4 delimiting the ring control chamber can be designed with a larger effective area than the area difference A5 - A3 - in this case it is sufficient to keep the ring control chamber in the switching position of the pilot valve 62 with the low pressure accumulator 66 to connect (see 3 ), since the forces acting in the opening direction - essentially resulting from the large ring face A4 and the area A3 - are greater than the forces acting in the closing direction, which are determined by the force of the spring and the pressure acting on the area A5.

The active logic 60 is designed so that it can flow through with minimal pressure loss and with appropriate control via the pilot valve 62 closes very reproducibly with minimal switching time. To optimize the subsequent closing behavior, the hub of the active logic 60 also be limited. Through this special construction of the active logic 60 Even with large nominal sizes, only small control oil flows are required to activate the active logic 60 can be opened and closed quickly and reproducibly.

Furthermore, through the active opening and closing of the active logic 60 by means of the pilot valve 62 and the safe locking of the active logic 60 the operational reliability is increased by means of the accumulator pressure. It is possible by actively closing the active logic 60 to freely choose the conditions for closing. This closing can take place, for example, as a function of the pressures, the load force, travel distances, travel speeds, etc.

As in 2 shown is the low pressure accumulator line 64 in a manner known per se via a 2/2-way valve, hereinafter referred to as accumulator shut-off valve 92 called, with the intensifier pressure chamber 28 connectable.

From the pressure line 58 branches off a discharge line 94 starting with a relief valve 96 is provided. This is designed as a 2/2-way valve and blocks the relief line in the illustrated spring-loaded basic position 94 towards tank T. By energizing a solenoid, the relief valve 96 be brought into a passage position in which the fluid connection to the tank T is opened.

The functionality of the in 2 casting unit shown 1 explained during the phases described above.

To prevent that when starting the casting cylinder 10 an opening of the active logic in the pre-filling phase 60 , also called storage shut-off valve, a pressure wave in the direction of the casting cylinder 10 which creates a start-up jolt, becomes the casting cylinder 10 preloaded before initiating the pre-filling phase. This takes place when the casting cylinder is retracted (after the last shot) 10 and intensifier 24 via the hydraulic pump 34 and the preload valve switched to its open position 48 as well as the flow control valve 54 , which is controlled via the electrohydraulic pilot control in the direction of the in 2 is adjusted position shown, in which the fluid connection between the port 3 and the port 2 is opened, the annular space 15th of the casting cylinder 10 and the intensifier annulus 32 to the maximum Pump pressure can be biased. The shut-off valve 42 and the preload valve 48 are preferably designed with a non-return function.

In a subsequent step, the melt is poured through the filling opening 19th into the firing chamber 18th the watering can 17th filled and the pre-filling phase initiated. The hydraulic pump is used for this 34 controlled via a ramp function and via the valve 42 the floor space 14th of the casting cylinder 10 charged to the accumulator pressure. The casting cylinder 10 thereby extends slowly and without starting jerk against the preload until it is in the annulus 15th absorbed fluid is compressed and thus there is an equilibrium of forces. It is essential here that this control ensures a jolt-free pressure equalization between the low-pressure accumulator 66 and the floor space 14th of the casting cylinder 10 he follows. Then you can use the active logic 60 (Accumulator shut-off valve) of the low-pressure accumulator 66 with the floor space 14th and via the low pressure shut-off valve 92 the low pressure accumulator 66 with the intensifier pressure chamber 28 get connected.

If the pump 34 can generate a sufficiently high pressure, this procedure is not required. With a correspondingly high pre-tensioned annulus 15th can also use the low pressure accumulator 66 about the active logic 60 on the piston chamber 14th be switched.

Then the flow control valve 54 adjusted via the pilot control in the direction in which the two connections 1 and 3 are connected so that the out of the annulus 15th displaced pressure medium in the manner of a regenerative circuit directly to the floor space 14th is fed. This enables the casting cylinder 10 is started up and moved gently (jerk-free, regenerative and controlled). This accelerates the melt and moves it towards the mold cavity 21 postponed. This takes place until the melt has reached the gate.

Through the regenerative process of the casting cylinder 10 Less pressure medium is drawn from the low-pressure accumulator in the pre-filling phase 66 removed so that this can be carried out with a smaller volume than with conventional solutions. Furthermore, due to the lower pressure drop at the flow control valve 54 a better resolution of the casting cylinder speed possible, so that the casting cylinder 10 can be moved at lower speeds.

Another advantage of the regenerative process is that due to the lower pressure loss at the flow control valve 54 and due to the fact that the pressure medium from the annulus 15th not against the tank pressure (0 bar) but against the pressure in the low-pressure accumulator 66 flows away, less cavitation and therefore less wear on the piston 11 and on the housing 13th of the casting cylinder and the associated control block occurs.

In addition, suitable control of the flow control valve 54 the pressure in the floor space 14th can be actively influenced in the sense of a pressure reduction.

As soon as the melt has reached the gate, the actual mold filling process (phase II) is initiated. In the event that the mold filling (injection) takes place at low mold filling forces, the process continues to be regenerative. Accordingly, at the point in time when the melt reaches the gate, the flow control valve is activated 54 , for example with a step function, adjusted to a position in which the pressure medium connection between the annular space 14th and the floor space 15th is further open, so that the melt with high injection speed (up to 10m / s) into the mold 20th is shot. It will continue to be driven regeneratively, ie from the annulus 15th displaced pressure medium is the increasing floor space 14th fed.

Such a procedure has the advantage that in phase II less pressure medium from the low-pressure accumulator 66 must be removed than is the case with conventional solutions.

In the event that the injection takes place at higher mold filling forces, the flow control valve is activated at the point in time at which the melt reaches the mold gate 54 brought into its closed position, for example, with a jump function, so that the pressure medium connection between the annular space 15th and the floor space 14th is interrupted. In parallel, the flow control valve 46 in the process, for example with a step function, opened to a predetermined opening cross-section towards the tank T. This causes the melt to be injected into the mold cavity at a high rate of injection 21 is shot, but in contrast to the procedure with low mold filling forces, there is no regenerative driving and thus the maximum force of the casting cylinder 10 can be used.

In principle, mixed forms are also conceivable in which the flow control valve is dependent on the load force 54 is only moved into its locked position during phase II.

Phase II can also be run completely regeneratively. However, this assumes that the required load force in phase II can also be achieved in the regenerative circuit. In this case the flow control valve could 46 im through a fast switching valve to relieve the annulus 15th to be replaced in phase III.

After the mold cavity has been completely filled 21 the transition to phase III takes place. For this purpose, the flow control valve is used at the end of the mold filling 54 via the pilot control in the direction of opening the connection from 3 to 2, so that the pressure booster annulus 32 via the flow control valve 54 with the line 44 connected is. Parallel to the adjustment of the flow control valve 54 becomes the flow control valve 46 open to tank T, so that by the pressure relief of the pressure booster annulus 32 the primary piston 26th accelerated and accordingly in the floor space 14th the high pressure is built up, so that the piston 11 the high pressure is applied and the melt is recompressed. When the desired downstream pressure is reached, the flow control valve is activated via a pressure regulator 54 reset again in the closing direction. In the event that the closing of the flow control valve 54 does not take place quickly enough, a pressure overshoot can be reduced by opening the connection from 1 to 3.

Accordingly, the flow control valve has 54 a dual function in that it is once the regenerative connection of the annulus 15th and the floor space 14th controls and, on the other hand, the acceleration of the pressure intensifier 24 (Multiplier) initiates. This dual use makes it possible to save a control valve compared to the solutions described above.

3 shows a hydraulic circuit diagram of a variant of the casting unit 1 according to 2 . One difference is that in the embodiment according to FIG 3 the booster unit not through a pressure intensifier 24 but through a high pressure accumulator 98 is formed via a high pressure storage valve 100 can be switched on. Also in the embodiment according to 3 is the flow control valve 54 adjustable via its electro-hydraulic pilot control against the force of the spring into the position shown, in which the fluid connection between the connections 1 and 3 is opened so that the annulus 15th with the floor space 14th is connected and the casting cylinder 10 can be used regeneratively. Via flow control valve 54 can make the connection between the ports 1 and 2 are opened, with a high-pressure storage line on the latter 102 is connected, in which the high pressure accumulator valve 100 is arranged.

Furthermore, there is the hydraulic pump 34 in the embodiment according to 3 designed as a variable displacement pump, for example in an axial piston design. The electric motor is accordingly 36 designed as a constant motor. It goes without saying that the circuit according to 3 a fixed displacement pump with the based 2 explained drive variants can be used.

Otherwise, the exemplary embodiment corresponds to FIG 3 essentially according to that 2 , so that reference can be made to the statements above with regard to the function and structure of the other components.

Before phase I is initiated, the high-pressure storage valve can be used 100 the pressure medium connection between port 2 of the flow control valve 54 and the high pressure accumulator 98 be opened - however, this high pressure does not work in the floor space 14th because port 2 is blocked. This floor space 14th is via the flow control valve 54 - as explained above - with the annulus 15th connected so that a regenerative process of the casting cylinder 10 he follows. The control during phases I and II of the casting process takes place analogously to the description of the mode of operation of the casting unit 1 according to 2 .

The high-pressure accumulator then becomes the transition to phase III 98 switched on. This is done by the flow control valve 54 is adjusted in a direction in which the direct connection between the annulus 15th and the floor space 14th controlled and the fluid connection between the port 2 and the port 1 is controlled so that accordingly in the floor space 14th the high pressure is effective. At the same time the flow control valve is 46 opened in the drain, so that from the annulus 15th displaced pressure medium to tank T can flow out. Through the use of the high pressure accumulator 98 the time-consuming acceleration of the classic pressure intensifier is no longer necessary 24 in phase III, so that less pressure medium and therefore less energy is required to accelerate. The flow control valve 54 in the inlet to the casting cylinder 10 must only be opened from 1 to 2 immediately before the required pressure build-up. Because the moving mass of the pressure intensifier 24 is omitted and therefore does not have to be braked, the pressure build-up can be more dynamic than in the exemplary embodiment according to FIG 2 respectively. The control quality is also increased. Another advantage is that the additional dead volume for immersing the piston rod 30th of the pressure intensifier 24 On the casting cylinder side, there is no need for the actuation of the pressure booster 24 due to its area ratio, the pressure medium required is not required. In this way, the pressure build-up can take place much faster with the same volume flow in the inlet. It also allows the use of a flow control valve designed with a smaller nominal size 54 . Charging the high-pressure accumulator 98 can be done, for example, via a high pressure pump or a pressure booster.

The applicant reserves the right to use the high-pressure accumulator directly 98 for the pressure build-up on the casting cylinder required for compaction 10 to direct its own independent patent claim.

4th shows a variant of the embodiment according to 2 , in which the pressure booster pressure chamber on the bottom 28 via a switching valve 104 with the pump line 40 and via another switching valve 106 can be connected to the tank T. The two switching valves are in the basic position shown 104 , 106 biased into their blocking position and can be switched to the open position by energizing a switching magnet, so that the pressure intensifier pressure chamber 28 either with the pressure at the outlet of the pump 34 pressurized (switching valve 104 opened) or is relieved towards tank T (switching valve 106 in open position).

Otherwise, the exemplary embodiment corresponds to FIG 4th based on 2 illustrated embodiment, so that further explanations are unnecessary.

The casting units described have the advantage over the conventional solutions that, thanks to the regenerative process of the casting cylinder 10 that from the annulus 15th displaced pressure medium directly to the floor space 14th of the casting cylinder 10 via the flow control valve 54 can be fed. This is also used to control the pressure build-up and pressure reduction in phase III. Another special feature is the active closing of the active logic 60 at the end of phase II.

The active logic can also be replaced by a shut-off valve and an external check valve.

A casting unit is disclosed, the casting cylinder of which can be moved regeneratively via a flow control valve in a pre-filling phase. A boosting unit, for example a pressure booster or a high-pressure accumulator, is also switched on via this flow control valve in a holding pressure phase.

List of reference symbols

1

Casting unit

10

Casting cylinder

11

piston

12th

Piston rod

13th

casing

14th

Floor space

15th

Annulus

16

Pouring piston

17th

Watering can

18th

Firing chamber

19th

Filling opening

20th

shape

21

Mold cavity

22nd

Pouring channel

24

Pressure intensifier / multiplier

26th

Primary piston

28

Pressure intensifier pressure chamber

30th

Piston rod

32

Pressure intensifier annulus

34

Hydraulic pump

36

Electric motor

40

Pump line

41

Line section

42

Check valve

44

management

46

Flow control valve (drain valve)

48

Preload valve

50

Preload line

52

Pressure relief valve

54

Flow control valve

56

Connecting line

58

Pressure line

60

Active logic

62

Pilot valve

64

Low pressure accumulator line

66

Low pressure accumulator

68

Seat

70

Main piston

84

Tranquility

88

management

90

Storage

92

Accumulator shut-off valve

94

Discharge line

96

Relief valve

98

High pressure accumulator

100

High pressure accumulator valve

102

High pressure storage line

104

Switching valve

106

Another switching valve

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102017220832 A1 [0002, 0035]
• DE 102005035170 B4 [0003, 0035]
• DE 102017221500 A1 [0004]

Claims (11)

Hydraulic casting unit of an original molding machine, in particular an injection molding, die casting or thixomolding machine, with a casting cylinder (10) designed as a differential cylinder, the piston (11) of which delimits a bottom space (14) on the bottom and an annular space (15) on the piston rod, with a control valve , which is designed to connect the annular space (15) to the floor space (14), and with a control valve for connecting a line (44) connected to the annular space (15) to a tank (T), as well as to a low-pressure source, the Can be connected to the floor space (14) via a shut-off valve device and with a hydraulic booster unit which is designed to support the extension movement of the casting cylinder (10) in a holding pressure phase, characterized in that the control valve is designed as a flow control valve (54), the valve slide of which the pressure medium connection between the floor space (14) and the annular space (15) opens in an adjustment direction euert and activated the amplification unit in a different adjustment direction. Casting unit after Claim 1 , the amplification unit being a high-pressure accumulator (98) which is connected to the floor space (14) in the other adjustment direction via the flow control valve (54). Casting unit after Claim 1 , wherein the amplification unit is a pressure booster (24), the primary piston (26) of which delimits a pressure booster annular space (32) with a smaller end face and a pressure booster pressure space (28) with a larger end face, which via an accumulator shut-off valve (92) with the Low pressure source can be connected, the pressure medium connection of the pressure booster annular space (32) to the line (44) being able to be opened via the flow control valve (54) in the other adjustment direction. Casting unit according to one of the preceding claims, wherein the flow control valve (54) is designed as a, preferably electrohydraulically, pilot-operated 3-way flow control valve. Casting unit according to one of the preceding claims, wherein the shut-off valve device is designed as a 2/2-way active logic (60) with a pilot valve (62). Casting unit according to one of the Claims 1 to 4th , wherein the shut-off valve device is designed as a valve arrangement with a shut-off valve assigned to the low-pressure source and a check valve arranged between the shut-off valve and the bottom space (14) of the casting cylinder (10). Casting unit according to one of the preceding claims, with a switching valve (92) for connecting a pressure medium flow path between the output of the shut-off valve device, in particular the active path logic (60) and the floor space (14) of the casting cylinder (10) and the tank (T). Casting unit according to one of the preceding claims, wherein the drain valve (46) is designed as an electrohydraulically piloted 2-way flow control valve. Casting unit according to one of the preceding claims, with a hydraulic pump (34), which is designed as a variable displacement pump or as a constant pump with servo motor and servo converter or as a variable pump with three-phase motor and frequency converter or as a variable pump with three-phase motor. Casting unit according to one of the preceding claims, with a device for preloading the casting cylinder (10) and / or the pressure booster (24). Casting unit after Claim 9 , with a shut-off valve (48) which is designed to connect the pressure connection of the hydraulic pump (34) via the flow control valve (54) to the pressure booster annulus (32) and / or to the annulus (15) of the casting cylinder (10).

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