EP0536734A1 - Unité de commande de fluide à mono- ou multi-étagés et sa méthode d'opération - Google Patents

Unité de commande de fluide à mono- ou multi-étagés et sa méthode d'opération Download PDF

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Publication number
EP0536734A1
EP0536734A1 EP92117141A EP92117141A EP0536734A1 EP 0536734 A1 EP0536734 A1 EP 0536734A1 EP 92117141 A EP92117141 A EP 92117141A EP 92117141 A EP92117141 A EP 92117141A EP 0536734 A1 EP0536734 A1 EP 0536734A1
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EP
European Patent Office
Prior art keywords
fluidic
control unit
control
pressure
unit according
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Application number
EP92117141A
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German (de)
English (en)
Inventor
Josef Egger
Heinrich Egger
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Hoerbiger Fluidtechnik GmbH
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Hoerbiger Fluidtechnik GmbH
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Filing date
Publication date
Application filed by Hoerbiger Fluidtechnik GmbH filed Critical Hoerbiger Fluidtechnik GmbH
Publication of EP0536734A1 publication Critical patent/EP0536734A1/fr
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15C—FLUID-CIRCUIT ELEMENTS PREDOMINANTLY USED FOR COMPUTING OR CONTROL PURPOSES
    • F15C3/00—Circuit elements having moving parts
    • F15C3/02—Circuit elements having moving parts using spool valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/16—Special measures for feedback, e.g. by a follow-up device

Definitions

  • 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.
  • hydraulic valves 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • the fluidic control units appear preferably as hydraulic control, regulating and switching valves.
  • hydraulic oil 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.
  • a fluidic control unit (1) is shown in the preferred embodiment as a hydraulic valve.
  • 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.
  • 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.
  • this regulating force (9) acts in the sense of negative feedback.
  • 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.
  • two oppositely acting control chambers can also be provided.
  • the control unit (1) is regulated from the output (P2, A).
  • a connection line (10) to the control chamber (8) is laid from the output (P2, A).
  • a hydraulic resistance (13) in the connecting line (10) which can also be present several times.
  • 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).
  • 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.
  • the pressure in the control chamber (8) increases.
  • the control force (9) increases and pushes the actuating piston (3) against the actuating force (7) in the closed position.
  • 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.
  • a pressure reduction against the tank pressure is regulated.
  • valve in a modification of the embodiment shown as a pressure limiter, can also have a common inflow and outlet (P1, P2) in connection with an actuating piston with a closing function.
  • P1, P2 common inflow and outlet
  • 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.
  • 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.
  • 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).
  • 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).
  • Such arrangements can also be implemented in other designs of the hydraulic control unit (1). They are not only advantageous for pilot operated valves.
  • the switching valve (27) can also have a different function and characteristic than the pressure reducing valve (25) shown.
  • 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).
  • 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).
  • 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).
  • 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).
  • 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).
  • 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).
  • 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).
  • Fig. 4 shows a variant of the above-described example in the form of a three-way current regulator (29).
  • the connecting line (11) opens into the inflow (P1).
  • the design and function of the control circuit is the same as in Fig. 3.
  • the inflow (P1) flows out against the tank (T) in the three-way flow regulator (29).
  • the tank drain is closed when the pressure drop at the throttle (18) falls below.
  • flank generator (30) 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.
  • 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).
  • 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).
  • FIG. 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).
  • 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.
  • the pulse generator behaves like a pressure reducing valve, in which the output pressure is set via (E1) .
  • 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.
  • 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.
  • 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.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • Theoretical Computer Science (AREA)
  • Control Of Fluid Pressure (AREA)
EP92117141A 1991-10-08 1992-10-08 Unité de commande de fluide à mono- ou multi-étagés et sa méthode d'opération Withdrawn EP0536734A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4133346 1991-10-08
DE19914133346 DE4133346A1 (de) 1991-10-08 1991-10-08 Verfahren zum betreiben einer ein- oder mehrstufigen fluidischen steuereinheit sowie fluidische steuereinheit

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EP0536734A1 true EP0536734A1 (fr) 1993-04-14

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EP92117141A Withdrawn EP0536734A1 (fr) 1991-10-08 1992-10-08 Unité de commande de fluide à mono- ou multi-étagés et sa méthode d'opération

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DE (1) DE4133346A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1050621A (fr) * 1900-01-01
US3126031A (en) * 1964-03-24 hayner
FR2263441A1 (fr) * 1974-03-06 1975-10-03 Volki Walter

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1050621A (fr) * 1900-01-01
US3126031A (en) * 1964-03-24 hayner
FR2263441A1 (fr) * 1974-03-06 1975-10-03 Volki Walter

Also Published As

Publication number Publication date
DE4133346A1 (de) 1993-04-15

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