EP0536734A1 - One or multi-stage fluid control unit and its operating method - Google Patents

Abstract

The invention relates to a method of operating a single- or multi-stage fluid control unit, in particular of a hydraulic valve, as well as to the control unit itself. The control unit is designed and operated like an electronic operational amplifier. To this end, there is an actuator (2), e.g. a piston, which is acted upon by an actuating force (7) and sets and controls the pressure and flow ratios between an inflow (P1) and an outlet (P2, A) and if need be a tank (T). In the process, a fluidic regulating force (9, 9') is derived as input from the output (P2, A) of the control unit (1) or an intermediate stage while reducing the pressure, which regulating force (9, 9') acts in a regulating manner on the actuator (2) and interacts with the actuating force (7). The fluidic regulating force (9, 9') can act in the sense of a negative feedback at the inverting input or a positive feedback at the non-inverting input. In relation to the apparatus, at least one fluid-filled control chamber (8, 8') is allocated to the actuator (2), which control chamber (8, 8') is connected in a network between at least two fluidic resistors (13, 14, 15, 13', 15') under fluidic resistors (13, 14, 15, 13' 15') and storage members (16, 17), of which at least one is connected to the output (P2, A) of the control unit (1) or an intermediate stage.

Description

The invention relates to a method for operating a single-stage or multi-stage fluidic control unit, in particular a hydraulic valve, and its design.

In practice, hydraulic valves are known which have a usually piston-shaped actuator which is acted upon by an actuator with an actuating force and which the pressure and flow conditions between an inflow (P1) and an outlet (P2, A) of the control unit and optionally one Tank (T) adjusts and controls. In such valves, a compensation chamber can also be provided on the piston rear for pressure compensation, which is connected to the outlet (P2, A) via a bore. The full outlet pressure then prevails in this compensation chamber. In flow control valves, it is also known to connect the space in front of the throttle to the compensation chamber. In all cases, only one line leads from the output side into the compensation chamber. This arrangement serves to build up a force support. Regulation of the known valves takes place from the input side by means of corresponding pilot valves or similar arrangements.

Known valves with pressure control have the disadvantage that the actuating force must act against the real outlet pressure. If high pressures or large flow rates are to be switched, this forces the control force to be increased by one or more pilot valves. Such valves are complex, complicated and expensive due to their multiple levels. They also tend to vibrate, can sometimes be insufficiently tuned and sometimes have a small working area. The timing of the known hydro valves can also be problematic. The tendency to vibrate requires damping measures, which in turn limit the switching time downwards. The timing also often depends on the design, but known valves are difficult to adapt to different requirements. This forces the construction of special valves with special properties and a variety of valve types.

It is an object of the invention to demonstrate a method and an embodiment for a fluidic control unit which enable a reduction in the construction effort in connection with better control properties.

The invention solves this problem with the features in the main method and device claim.

The fluidic control unit is regulated from the output side, with low regulating forces being achievable by reducing the pressure. The fluidic control unit is constructed analogously to an electrical operational amplifier and is operated accordingly, the output variable being connected to an inverting input on the actuator.

With this operating and design concept of the fluidic control unit, a wide range of control and regulating effects can be achieved with just a few basic concepts. The construction effort is considerably less, since the low control forces achieved through the pressure reduction elaborate reinforcement measures as in the prior art can be omitted. The fluidic control units can be more easily adapted to the requirements by varying or simply adjusting the fluidic resistances and have large working areas in some designs. The design of the fluidic control units is easier to control and has a more favorable time and vibration behavior than was previously known. With the basic concepts specified in the claims, any functions can be represented in a fluidic way, which was previously only possible with electrical units. The fluidic control units can be regarded as fluidic operational amplifiers with all their possible uses and modifications.

In their specific designs, the fluidic control units appear preferably as hydraulic control, regulating and switching valves. Instead of hydraulic oil, other fluids, including gases, can also be used. The design of the actuators and the actuators is arbitrary. For reasons of simplicity and precision, actuating pistons and electromagnets are preferred.

In the subclaims, advantageous refinements of the invention are specified in some concrete exemplary embodiments. In addition, any other training and functions can be trained with the specified individual parts and the operating method.

Fig. 1:

ein Druckminderventil in schematischer Darstellung und mit Schaltsymbol,

Fig. 2:

eine Variante als vorgesteuertes Druckminderventil mit Schemadarstellung und Schaltsymbol,

Fig. 3:

einen Zwei-Wege-Stromregler in Schemadarstellung und mit Schaltsymbol,

Fig. 4:

eine Variante zu Fig. 3 als Drei-Wege-Stromregler,

Fig. 5:

eine weitere Variante als Flanken-Generator mit Schemadarstellung und Schaltsymbol,

Fig. 6:

eine Abwandlung von Fig. 5 in Form eines Puls-Generators und

Fig. 7:

eine Abwandlung von Fig. 1 als Druckminderventil mit Mitkoppelung.

The invention is shown schematically and by way of example in the drawings. In detail show:

Fig. 1:

a pressure reducing valve in a schematic representation and with a switching symbol,

Fig. 2:

a variant as a pilot-operated pressure reducing valve with schematic representation and switching symbol,

Fig. 3:

a two-way current controller in schematic representation and with a circuit symbol,

Fig. 4:

3 as a three-way current regulator,

Fig. 5:

another variant as an edge generator with schematic representation and circuit symbol,

Fig. 6:

a modification of Fig. 5 in the form of a pulse generator and

Fig. 7:

a modification of Fig. 1 as a pressure reducing valve with positive feedback.

In the drawings, a fluidic control unit (1) is shown in the preferred embodiment as a hydraulic valve. In a similar way, pneumatic valves or other types of fluidic control units can also be constructed with appropriate adaptation to the fluid requirements.

The fluidic control units (1) each have an inflow (P1) and an outlet (P2) or (A) and occasionally also a tank (T). In some cases, e.g. In the case of pressure relief valves, the inflow (P1) and outlet (P2) or (A) can also coincide. The control units (1) can be integrated into fluidic, in particular hydraulic, networks or systems.

In the drawings, circuit symbols are also given for the schematic valve representations with the lines and assemblies of the control units (1). The fluidic control units (1) behave similarly to electrical operational amplifiers in their training and function.

The control units (1) each consist of an actuator (2), preferably in the form of an adjusting piston (3) provided with one or more control edges, which is moved axially back and forth. An actuator (6) acts on one side, which develops an axial actuating force (7). The actuator (6) preferably consists of a controllable electromagnet. 5, 6 and 7 illustrate, the actuator (6) can also be designed as a fluid, in particular hydraulic drive. The control piston (3) has a corresponding control surface (4). Combinations of mechanical and fluidic actuators (6) can also be provided (see FIG. 7). In the case of simple designs, springs or the like other simple components can also be considered.

A control chamber (8) is preferably assigned to the actuator (2) or control piston (3) on the opposite side, in which a fluidic control force (9) is developed which acts on the control surface (5) Actuator (2) or the actuating piston (3) acts. Depending on the desired function of the control unit (1), this regulating force (9) acts in the sense of negative feedback. Furthermore, it can act in the sense of positive feedback (FIG. 7), specifically in a combination or as an alternative to negative feedback. Such training makes sense for some control concepts, for example to influence dynamic behavior. In this case, two oppositely acting control chambers can also be provided.

The control unit (1) is regulated from the output (P2, A). In the various exemplary embodiments, a connection line (10) to the control chamber (8) is laid from the output (P2, A). For the purpose of reducing the pressure and generating the lowest possible control force (9), there is a hydraulic resistance (13) in the connecting line (10), which can also be present several times. As can be seen from the exemplary embodiment of FIG. 2 described in more detail below, the fluidic resistor (s) (13, 14) can also be combined with one or more storage elements (17). 5 there is the further alternative of connecting a fluidic storage element (16) to the connecting line (10) instead of one or more fluidic resistors (13, 14).

A connecting line (11) continues from the control chamber (8). At least one further fluidic resistor (15) and / or a storage element (16, 17) is arranged in this connecting line (11). The memory elements (16, 17) are used, for example, for the purpose of filtering certain frequencies, causing phase shifts, forming integrator and differentiator functions, etc. They are arranged and function with capacitors in an electrical operational amplifier comparable.

The control chamber (8) is thus integrated into a network of at least two fluidic resistors (13, 14, 15) or a combination of at least two components in the form of fluidic resistors (13, 14, 15) and storage elements (16, 17).

According to the various exemplary embodiments, the connecting line (11) can open into the tank (T), the inflow (P1) or elsewhere. It can also be connected to a further pressure line (24).

The fluidic resistors (13, 14, 15) can have different designs. The desired magnitude of the pressure in the control chamber (8) and thus the desired magnitude range of the regulating force (9) is set via its setting. The fluidic resistors (13, 14, 15) can be fixed or variable. In the preferred embodiment, they consist of adjustable nozzles or throttles. However, they can also be designed as diaphragms or in another suitable, pressure-reducing manner. The coordination of the fluidic resistances (13, 14, 15) and the storage elements (16, 17) depends on the actuating force (7), the masses to be moved, the size of the flow (P1) and the output (P2, A) to be switched pressures or flow rates and the size of the control surface (5) and other design factors. The coordination is advantageously selected so that low control forces (9) result, which are, for example, in the range of the actuating forces (7) that can be generated directly by an electromagnet. This means that pilot control units can be dispensed with.

Fig. 1 shows the control unit (1) in the form of a pressure reducing valve (25). The actuating piston (3) switches the inflow (P1) to an outlet (P2) to limit and maintain a pressure that can be selected via the actuating force (7). The connecting line (10) branches off from the outlet (P2) with a fluidic resistor (13) to the control chamber (8). The control chamber (8) is connected on the other side to the tank (T) via the connecting line (11) and a second fluidic resistor (14). The tank line (12) can pass through a pressure chamber on the control piston (3). The small symbol shows the fluid circuit.

If the pressure at the outlet (P2) rises above the specified value, the pressure in the control chamber (8) also increases. The control force (9) increases and pushes the actuating piston (3) against the actuating force (7) in the closed position. In the area of the inlet (P1), the control piston (3) is pressure-balanced, so that the regulating force (9) only acts against the actuating force (7) and possibly the tank pressure. In the embodiment shown, a pressure reduction against the tank pressure is regulated. Alternatively, it is also possible to regulate against the atmosphere or against another reference pressure. As soon as the output pressure through the closed control piston (3) falls below the set value, the pressure in the control chamber (8) drops accordingly, so that the positioning force (7) can open the control piston (3) and thus the inflow (P1) again.

In a modification of the embodiment shown as a pressure limiter, the valve can also have a common inflow and outlet (P1, P2) in connection with an actuating piston with a closing function. The switching arrangement and function of the hydraulic resistors (13, 15) is the same here.

Fig. 2 shows a variant in the form of a pilot-operated pressure reducing valve. The pilot valve (26) switches the switching valve (27) for the large flow rates via its control piston (3). The switching valve (27) has a floating switching piston (20) on which pressure chambers (21, 22) are arranged on both sides. The inflow (P1) of the switching valve (27) is connected to the actuating piston (3). If the pressure in the control chamber (8) rises due to an increased pressure at the outlet (P2), the actuating piston (3) opens and switches the inflow (P1) to the pressure chamber (22). As a result, the switching piston (20) is brought into the closed position. If, on the other hand, the pressure at the outlet (P2) falls below the specified value, the actuating force (7) outweighs the correspondingly reduced regulating force (9), so that the other pressure chamber (21) is connected by the inflow (P1), and the switching piston (20 ) in the open position. The actuating piston (3) is designed so that the excess fluid can flow out of the pressure chamber (21, 22) that is not acted upon via the connecting line (11) and the tank line (12).

The pilot operated valve (26) has a special vibration-damping design in this exemplary embodiment. For this purpose, a fluidic resistor (13) is first connected to the connecting line (10) branching off from the output (P2). A storage element (17) is then arranged, which has a spring-loaded piston and can be connected to the tank (T). After the branch to the storage member (17) and before the branch to the control chamber (8) there is another fluidic resistor (14). A second storage element (17) of the type described above is located in front of one in the connecting line (11) third fluidic resistor (15) arranged. The network of fluidic resistors (13, 14, 15) and storage elements (17) leads to a delay in the pressure increase in the control chamber (8). Certain, especially too high frequency components in the outlet pressure at (P2) can be filtered out. This results in better switching behavior. Optimal behavior with complete suppression of vibrations results if there is a phase shift of the inverting input by 90 ^o . This can be achieved by appropriate coordination of the fluidic resistances (13, 14, 15) and the capacities and spring loads of the storage elements (17).

Such arrangements can also be implemented in other designs of the hydraulic control unit (1). They are not only advantageous for pilot operated valves. In addition, the switching valve (27) can also have a different function and characteristic than the pressure reducing valve (25) shown. Depending on the design and control requirements, a single fluidic resistance (13), without the storage elements (17) and the second fluidic resistance (14), can also be sufficient for the function of the pilot-operated valve. Such an arrangement would be sufficient for the pure function of the pilot-controlled valve (26).

In the embodiment shown in FIG. 2, the connecting line (10) is arranged at the outlet (P2) of the switching valve (27) and thus at the outlet of the entire control unit (1). Alternatively, the feed line with the appropriate switching and control function can also branch off from the output of an intermediate stage of a multi-stage control unit (1). In the exemplary embodiment shown, this would be, for example, on the connecting lines between the pilot valve (26) and the two pressure chambers (21, 22). possible. The switching valve (27) can then receive a network corresponding to the desired function.

Fig. 3 shows the fluidic control unit (1) in the form of a two-way flow controller (28). Here, the control piston (3) switches the inflow (P1) via an intermediate space (23) and a subsequent throttle (18) to the outlet (P2). The throttle (18) can have a fixed setting, the amount being set via the actuating force (7). In this embodiment, one connecting line (10) branches off behind the throttle (18) in the direction of flow and has a fluidic resistance (13) in front of the control chamber (8). The other connecting line (11) has a second fluidic resistance (15) and opens into the intermediate space (23). At the outlet (P2), a pressure line (24) branches off behind the throttle (18) and places the outlet pressure on a control surface (4) on the control piston (3).

The two fluidic resistances (13, 15) are considerably smaller than the throttle (18) in order to keep the measurement and control error as small as possible. A setting factor "k"<1 results from the fluidic resistances (13, 15), which must be multiplied by the pressure drop across the throttle (18). In the control chamber (8) there is therefore a control force (9) directed against the actuating force (7), which results from the pressure drop across the throttle (18) multiplied by the factor "k". The actuating force (7) is present on the other side of the actuating piston (3). The outlet pressure also acts on both sides. With this arrangement, the actuating force (7) is weighed against the pressure drop across the throttle (18) and the resulting relative regulating force (9) on the actuating piston (3). If the pressure drop across the throttle (18) increases and the flow rate at the outlet (P2) increases, the pressure in the control chamber (8) and thus the control force (9) increases with the result that the control piston (3) closes the inflow (P1). However, if the pressure drop across the throttle (18) falls below the set value, the actuating force (7) outweighs the regulating force (9) so that the actuating piston (3) opens again.

Fig. 4 shows a variant of the above-described example in the form of a three-way current regulator (29). In this case, the connecting line (11) opens into the inflow (P1). Otherwise, the design and function of the control circuit is the same as in Fig. 3. When the pressure drop across the throttle (18) is exceeded, the inflow (P1) flows out against the tank (T) in the three-way flow regulator (29). Conversely, the tank drain is closed when the pressure drop at the throttle (18) falls below.

5 shows a special variant of the fluidic control unit (1) in the form of a so-called flank generator (30). It is a control valve that allows the representation of an at least approximated integrating function via the difference between the input pressures (E1) and (E2). The flank generator (30) can be used as an integrator in a fluidic PID controller or PI controller.

The actuating piston (3) is acted on the left side by an actuator (6), which is fluid in this case. A memory element (16) in the form of a sliding memory is connected in the connecting line (10) branching off from the output (A). It consists of a fluid-filled housing (19) which is divided into two storage chambers (32, 33) by a piston (34). The piston (34) is acted upon by springs (35) from both sides, which hold it in its desired position in the stationary state, preferably in the middle of the housing. The one storage chamber (32) is with connected to the output (A), while the other storage chamber (33) is connected to the control chamber (8) via a line piece (10 ''). The connecting line (11) in turn branches off from the control chamber (8) or the line section (10 '') with a fluidic resistance (15). The fluid line of the actuator (6) is designated (E1). The fluid line leading into the higher-level system after the fluidic resistance (15) bears the designation (E2). The actuating piston (3) is actuated as a function of the pressures in (E1) and (E2), the storage element (16) ensuring that the volume flow from the inflow (P1) to the outlet (A) is switched on and off smoothly. As soon as the pressure in (E1) is higher than in (E2), the control piston (3) moves to the right and switches the inflow (P1) to the outlet (A). This increases the pressure in the storage chamber (32). The piston (34) moves to the right and pushes the fluid from the storage chamber (33) into the control chamber (8), the process being controlled via the size of the pressure in (E2) and the fluidic resistance (15). Due to the pressure increase in the control chamber (8), the actuating piston (3) moves relatively slowly. A square-wave signal of the pressure in (E1) therefore manifests itself at the output (A) as a soft edge signal. The change in the outlet pressure corresponds approximately to the integral over the pressure difference between (E1) and (E2) over the time until the inlet pressure prevails at outlet (A). Conversely, the control piston (3) closes when (E2) the pressure in (E1) increases. The storage element (16) in turn results in a damping effect and thus a smooth switching off of the fluid flow at the outlet (A).

In the variation to the exemplary embodiment shown, the actuator (6) can also be designed in any other way, for example again as an electromagnet. The arrangement of the resistor (15) and the Memory element (16) can also be used as an integrating component in other designs of control units (1).

6 shows a further variant as a so-called pulse generator. This has the at least approximate function of a differentiator. The pulses in the outlet pressure are controlled via (E1) and (E2).

The output (A) is connected to the control chamber (8) via the connecting line (10) and a fluidic resistor (13). This time, the memory element (16) described above is arranged in the connecting line (11) which is connected to (E2).

When (E1) is switched on, the control piston (3) is moved to the right and the inflow (P1) is switched to the output (A). At the same time, the fluid flows via the connecting line (10) and the resistor (13) into the control chamber (8) and the storage chamber (33) of the storage element (16). There is a soft rising edge for the pressure in the control chamber (8). This leads to a pressure peak in the outlet pressure. If the pressure in (E2) is now increased, this causes the control piston (3) to close via the storage element (16) and the volume thrust into the control chamber (8), and thus a drop in the pressure at the outlet (A). If the pressure in (E2) is quickly increased in the manner of a square-wave signal, there is a pulse-like pressure drop at the outlet (A). Conversely, if there is a drop in pressure in (E2), the pressure at output (A) is increased in a pulsed manner. The pressure behavior at the outlet (A) is the difference between the pressure in (E1) minus a value that is formed from the approximate differential of the pressure difference between (E1) and (E2) over time multiplied by a factor "k" . The factor "k" results as a function of the storage element (16) of the hydraulic resistance (13) and the control surface (5) etc. In the stationary state, the pulse generator behaves like a pressure reducing valve, in which the output pressure is set via (E1) . In this embodiment too, the actuator (6) at (E1) can be designed in a different way.

Fig. 7 shows the control unit (1) in the form of a pressure reducing valve (25) with negative and positive feedback. The counter-coupling part corresponds to the embodiment in FIG. 1. In a modification of this embodiment, the valve (25) shown in FIG. 7 has a second control chamber (8 ') for the positive feedback, which is located on the side of the actuator (6) and which Positioning force (7) supported. The second control chamber (8 ') is connected to the outlet (P2) via a connecting line (10') with a first fluidic resistor (13 '). The second control chamber (8 ') is also connected to the tank line (12) by means of a further connecting line (11') and a second fluidic resistor (15 '). The connecting line (11 ') branches off from the connecting line (11) behind its fluidic resistance (15). A pressure is generated in the second control chamber (8 ') which generates a second regulating force (9') which, together with the actuating force (7), acts against the regulating force (9). In this way, the ratio of control force (9) to actuating force (7) can be varied.

With positive feedback, the output (P2) acts on the non-inverting input. The small circuit symbol in turn illustrates the circuit in an electrical operational amplifier.

The variant of the positive feedback can also be realized with the other designs of the control unit (1) shown. It can also be supplemented and expanded in the manner described above with storage elements (16, 17) or other components. The coupling and the corresponding structure of the control unit (1) can also be realized as an independent construction and control variant with previously known valves according to the prior art.

PARTS LIST

A

exit

E1

Fluid line

E2

Fluid line

P1

Inflow

P2

exit

T

tank

1

Control unit

2nd

Actuator

3rd

Adjusting piston

4th

Control surface

5

Control surface

6

Actuator

7

Positioning force

8th

Tax chamber

8th'

second control chamber

9

Control force

9 '

second regulating force

10th

Connecting line

10 '

Connecting line

10 ''

Pipe section

11

Connecting line

11 '

Connecting line

12

Tank line

13

Resistance, nozzle

13 '

Resistance, nozzle

14

Resistance, nozzle

15

Resistance, nozzle

15 '

Resistance, nozzle

16

Storage member

17th

Storage member

18th

throttle

19th

casing

20th

Shift piston

21

Pressure chamber

22

Pressure chamber

23

Space

24th

Pressure line

25th

Pressure reducing valve

26

Pilot valve

27

Switching valve

28

Two-way current regulator

29

Three-way current regulator

30th

Edge generator

31

Pulse generator

32

Storage chamber

33

Storage chamber

34

piston

35

feather

Claims (18)

Method for operating a single or multi-stage fluidic control unit, in particular a hydraulic valve, with at least one actuator (2), which is acted upon by an actuating force (7), the pressure and flow conditions between an inflow (P1) and an outlet (P2, A ) the control unit (1) and optionally a tank (T) and controls, a fluidic control force (9, 9 ') being derived as an input from the output (P2, A) of the control unit (1) or an intermediate stage, which acts regulatingly on the actuator (2) and acts together with the actuating force (7). Method according to claim 1, characterized in that the fluidic control force (9) acts in the sense of negative feedback at the inverting input. Method according to claim 1 or 2, characterized in that the fluidic control force (9 ') acts in the sense of positive feedback at the non-inverting input. Fluidic control unit, in particular hydraulic valve, with one or more stages and with at least one actuator (2), which is acted upon by an actuating force (7), the pressure and flow conditions between an inflow (P1) and an outlet (P2, A) of the control unit (1) sets and controls, the actuator (2) being assigned at least one fluid-filled control chamber (8, 8 ') in of which a fluidic control force (9,9 ') can be generated, the control chamber (8,8') in a network between at least two fluidic resistors (13,14,15,13 ', 15') or fluidic resistors (13,14 , 15, 13 ', 15') and memory elements (16, 17), at least one of which is connected to the output (P2, A) of the control unit (1) or an intermediate stage. Control unit according to Claim 4, characterized in that the fluidic resistances (13, 14, 15, 13 ', 15') can be set in a fixed or variable manner. Control unit according to claim 5 or 6, characterized in that the fluidic resistors (13, 14, 15, 13 ', 15') are designed as nozzles, throttles or screens. Control unit according to Claim 4 or one of the following, characterized in that the fluidic resistances (13, 14, 15, 13 ', 15') are matched to one another in such a way that the resulting regulating force (9) is of the order of magnitude that of the actuator (6) generated control force (7). Control unit according to claim 4 or one of the following, characterized in that the actuator (6) is designed as a controllable electromagnet. Control unit according to Claim 4 or one of the following, characterized in that at least one fluidic resistor (13, 14, 13 ') or one storage element (16) is located in one of the outputs (P2, A) to the control chamber (8,8 ') leading connecting line (10,10') is arranged. Control unit according to claim 9, characterized in that two fluidic resistors (13, 14, 13 ') with an interposed memory element (17) are arranged in the connecting line (10, 10'). Control unit according to Claim 4 or one of the following, characterized in that at least in a connecting line (11, 11 ') between the control chamber (8, 8') and the tank (T), a throttle chamber (25) or the inflow (P1) a fluidic resistor (15, 15 ') is arranged. Control unit according to Claim 11, characterized in that a storage element (17) is assigned to the fluidic resistor (15, 15 '). Control unit according to claims 9 and 10, characterized in that in order to form a pressure reducing valve (25) in each case a fluidic resistor (13, 15, 13 ', 15') in the branch and return line (10, 11, 10 ', 11') is arranged and the return line opens into the tank (T). Control unit according to claims 9 and 11, characterized in that to form a two- or three-way current regulator (28, 29) the connecting line (10) branches off from the outlet (P2) in the flow direction behind a throttle (18) and a fluidic resistance (13), where the connecting line (11) branches off with a fluidic resistance (14) from an intermediate space (23) or from the inflow (P1) and from the outlet (P2) a pressure line (24) to a control surface (4) on the actuator which supports the actuating force (7) (2) leads. Control unit according to Claims 9 and 11, characterized in that, in order to form an edge generator (30) in the connecting line (10), a memory element (16) in the form of a sliding memory is arranged, the one memory chamber (32) of which has the output (A). and whose other storage chamber (33) is connected to the control chamber (8), a fluidic resistor (15) being connected in the connecting line (11). Control unit according to Claims 9 and 11, characterized in that a fluidic resistor (13) is arranged in the connecting line (10) to form a pulse generator (31) and a storage element (16) in the form of a sliding memory is arranged in the return line. Control unit according to claim 4 or one of the following, characterized in that the actuator (2) with the control chamber (8) are arranged in a pilot valve (20) which controls the fluid flow for a switching valve (21), in particular a pressure reducing valve, for higher pressures or controls flow rates. Control unit according to Claim 17, characterized in that the connecting line (10) has two fluidic resistors (13, 14) with an interposed memory element (17), a fluidic resistor (15) with an upstream memory element (17) in the connecting line (11) ) is arranged.

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