EP0515639B1 - Systeme hydraulique - Google Patents

Systeme hydraulique Download PDF

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Publication number
EP0515639B1
EP0515639B1 EP92901394A EP92901394A EP0515639B1 EP 0515639 B1 EP0515639 B1 EP 0515639B1 EP 92901394 A EP92901394 A EP 92901394A EP 92901394 A EP92901394 A EP 92901394A EP 0515639 B1 EP0515639 B1 EP 0515639B1
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EP
European Patent Office
Prior art keywords
pump
pressure
consumer
hydraulic system
control
Prior art date
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.)
Expired - Lifetime
Application number
EP92901394A
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German (de)
English (en)
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EP0515639A1 (fr
Inventor
Otwin Eich
Franz-Peter Salz
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Oerlikon Barmag AG
Original Assignee
Barmag AG
Barmag Barmer Maschinenfabrik AG
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Publication of EP0515639A1 publication Critical patent/EP0515639A1/fr
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    • 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
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/08—Servomotor systems incorporating electrically operated control means
    • F15B21/087—Control strategy, e.g. with block diagram
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2221—Control of flow rate; Load sensing arrangements
    • E02F9/2225—Control of flow rate; Load sensing arrangements using pressure-compensating valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/06—Control using electricity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/08—Regulating by delivery pressure
    • 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
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
    • F15B11/163—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load for sharing the pump output equally amongst users or groups of users, e.g. using anti-saturation, pressure compensation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B2205/00—Fluid parameters
    • F04B2205/07—Pressure difference over the pump
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20546—Type of pump variable capacity
    • F15B2211/20553—Type of pump variable capacity with pilot circuit, e.g. for controlling a swash plate
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/25—Pressure control functions
    • F15B2211/253—Pressure margin control, e.g. pump pressure in relation to load pressure
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • F15B2211/3053—In combination with a pressure compensating valve
    • F15B2211/30535—In combination with a pressure compensating valve the pressure compensating valve is arranged between pressure source and directional control valve
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3105—Neutral or centre positions
    • F15B2211/3111—Neutral or centre positions the pump port being closed in the centre position, e.g. so-called closed centre
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/327—Directional control characterised by the type of actuation electrically or electronically
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/605—Load sensing circuits
    • F15B2211/6051—Load sensing circuits having valve means between output member and the load sensing circuit
    • F15B2211/6054—Load sensing circuits having valve means between output member and the load sensing circuit using shuttle 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6306—Electronic controllers using input signals representing a pressure
    • F15B2211/6309—Electronic controllers using input signals representing a pressure the pressure being a pressure source supply pressure
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6306—Electronic controllers using input signals representing a pressure
    • F15B2211/6313—Electronic controllers using input signals representing a pressure the pressure being a load pressure
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6333—Electronic controllers using input signals representing a state of the pressure source, e.g. swash plate angle
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/65—Methods of control of the load sensing pressure
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/665—Methods of control using electronic components
    • F15B2211/6652—Control of the pressure source, e.g. control of the swash plate angle
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders

Definitions

  • the invention relates to a hydraulic system according to the preamble of the claim, known from US-A-4,712,376.
  • this hydraulic system the measurement of the current delivery rate is to be carried out by detecting the pump speed. From this, the positions of the control valves are then to be corrected by means of a computer with the aid of previously determined nominal values from an electronic memory.
  • Another hydraulic system is known from DE 26 51 325 C2.
  • a control valve is notified on the one hand of the pressure at the pump and on the other hand of the highest load pressure. If the pump can no longer deliver the volume flow required by the valves assigned to the individual consumers, the pressure difference between the pressure of the pump and the highest load pressure is reduced.
  • the control valve consequently reduces the supply to the control pressure transmitter, by means of which the valves assigned to the consumers are actuated. This limits the flow of the valves. However, this limitation only becomes effective if there is already an excessive demand.
  • the object of the invention is to design the hydraulic system so that it is not susceptible to vibration and that any weighting and adaptation of the individual consumer flows to the operating parameters of the pump is also possible.
  • the solution results from the characterizing part of claim 1.
  • the solution has the advantage that, in contrast to the previous hydraulic systems, the operating state of the pump is recorded directly. Fluctuations in the operating state can therefore be effectively compensated for.
  • the control signals of the valves are reduced.
  • By measuring the pump current it can always be determined whether the supply of the individual consumers is guaranteed. This prevents undersupply.
  • the reduction of consumer currents can take place proportionally. However, a reduction according to priorities is also possible if, for. B. an individual consumer should not reduce his speed in contrast to the others.
  • control circuit which is the subject of this invention, intervenes only in exceptional cases, namely when the pumpable pump flow is not sufficient for the consumer flows set on the respective valves, which in total result in the current flow rate.
  • the current flow rate is reduced by reducing the respective consumer flows supplied.
  • Standard measuring devices are available for measuring the current delivery rate of the pump.
  • the current delivery volume can be measured by connecting the valves to the valves assigned to the individual consumers in the pump line (total delivery line), ie before the branching off of the consumer lines lead, a throttle or orifice arranged and the pressure drop is measured at this orifice.
  • the current delivery rate based on the predetermined possible delivery rate - at a given speed - can also be determined by the configurations according to claims 2 and 3.
  • valves that are assigned to the consumers. Basically, it can be assumed that these valves are adjusted electromagnetically or hydraulically from the outside, that is, by hand or by external input parameters. According to this invention, however, an adjustment signal for reducing the actuation of the valve piston is superimposed on these input signals if it is determined in the hydraulic system by measuring the current delivery quantity that the pumpable pump flow is exceeded.
  • the predeterminable pumpable pump current does not necessarily correspond to the maximum pumpable pump current. Rather, a lower limit, e.g. B. 80% of the maximum conveyable pump flow. This ensures that the hydraulic system does not fall out of its control range due to an absolute overload of the pump.
  • the adaptation of the consumer flows to the specified pump flow that can be conveyed when the limit value is exceeded is basically achieved by reducing the sum of the consumer flows to the specified limit value. In the simplest case, this can be done by reducing all consumer flows by the same percentage. However, it is also possible to weight the control signals, by means of which the consumer currents are reduced, differently for each consumer. This allows individual consumers to be given priority over other consumers. It can e.g. B. ensure that such consumers, for safety reasons, always with a certain consumer current have to be loaded, e.g. B. hydraulic brakes have priority over other consumers. This will be discussed later.
  • the embodiment of the invention according to claim 2 takes advantage of the knowledge that the delivery rate is also determined by the deflection of the balance piston of a 3-way pressure balance, which is deflected by the pressure difference between the pump pressure and the highest load pressure.
  • the current delivery rate is measured by measuring the deflection of the piston of a 3-way pressure compensator, which serves to keep the pressure difference between the pump pressure and the highest consumer pressure constant in a superimposed control loop.
  • the claim 3 relates to a hydraulic circuit with a control pump.
  • the current delivery volume is adjusted by relative adjustment between the stator (stationary part of the pump) and the rotor (rotating part of the pump) (see, for example, DE 26 51 325 C2), namely - in the preferred case - depending the pressure difference between the highest consumer pressure and the pump pressure.
  • the control position of the control pump is also used to measure the current flow.
  • a constant pump is used as the feed pump, which delivers a flow rate that is constant over time.
  • the delivery rate is measured immediately. That could e.g. B. happen directly by means of a built-in throttle on which a pressure difference is determined.
  • this can also be done by a 3-way pressure differential balance built into the delivery line, the balance piston of which is given the pressure difference between the pump pressure and the highest load pressure, the part of the flow rate not required to maintain this pressure difference depending on the position of the balance piston a bypass to the tank is derived.
  • either the position of the piston of the pressure compensator or the oil flow in the bypass to the tank can be used as a measure of the delivery flow provided for all the consumers.
  • This signal representing the flow rate is in turn compared in a comparator with a maximum flow rate and the difference signal is used to adjust or limit the flow rate supplied to the individual consumers.
  • this signal can either be superimposed with the delivery rate or the torque and / or the delivery pressure of the pump.
  • the special meaning of the invention according to claim 1 in the embodiment according to claims 2 and 3 is that the pump current is regulated by adapting the consumer currents to a predetermined limit value (pump current that can be conveyed), but this regulation only functions when the specified limit is reached.
  • the control pump or pressure differential balance is included in a second control circuit as a measuring element. So several control loops are superimposed.
  • An internal control circuit uses the pressure difference delta p between the pump pressure and the highest load pressure as the control variable and the control position of the control pump or the pressure compensating piston as the control variable.
  • the pressure difference delta p is measured on a piston and specified by dimensioning the spring of the pressure differential balance.
  • the control position of the control pump or the differential pressure balance ie. H. the manipulated variable is specified.
  • the superimposed outer control loop uses the currently measured delivery rate, ie the position of the piston of the differential pressure compensator in the sense of claim 2 or the control position of the control pump in the sense of claim 3 in order to be used in an emergency, ie Exceeding the limit value representing the pump flow that can be pumped, by adjusting the consumer flows as a manipulated variable, to keep the control variable specified by the limit value constant, namely the current flow rate.
  • the adaptation of the consumer flows of the individual consumers to the predetermined, maximum pumpable pump flow can also be achieved by superimposing the measurement signal obtained from the measurement of the current delivery quantity (deflection of the balance piston according to claim 2, control position of the control pump according to claim 3) with the pump output corresponding to the pump torque ( Delivery volume x delivery pressure) and / or the delivery pressure.
  • This has the advantage that a desired weighting of the delivery rate, the delivery torque and the delivery pressure of the control pump can be predetermined when the valve position is adapted to the maximum pump flow.
  • the current delivery capacity determined from the respective control position of the pump and the delivery pressure of the pump by multiplication or the torque of the pump is compared with a target torque and the output signal obtained from the difference is superimposed according to a selectable function, such that only when one is exceeded Given the predetermined drive torque, the position and adjustability of the valves assigned to the individual consumers are influenced, but not below this limit value.
  • the position and adjustability of the valves assigned to the individual consumers can be influenced when a certain pressure is exceeded by superimposing the delivery pressure after a certain function, but not below this pressure or only with a certain percentage.
  • the maximum external load is also taken into account when influencing the valves assigned to the consumers, in particular directional valves.
  • a pressure compensator can also be arranged in front of each valve, the pressure difference between the delivery pressure and consumer pressure, which is determined by a spring, which is taken off behind the respective valve, by adjusting the spring force as a function of the control position or superimposed on the torque and / or superimposed on the delivery pressure the control pump is adapted.
  • a setpoint processing is expedient.
  • the setpoints are the manually or automatically specified control signals for the valves assigned to the consumers. These externally entered setpoints can be fed to the system via attenuators (ramps). This specifies the rates of change at which the consumer currents can change if the setpoints entered change suddenly. It is thereby achieved that the adjustment speed of the pump or pressure differential balance is sufficient in any case to follow the change in the consumer flows over time. There can therefore be no shortage of consumers for a short time. Furthermore, the consumer flows requested by the entered target values can be roughly adapted to the maximum flow rate that can be supplied by the pump.
  • the setpoints entered from outside are brought into dependence on the sum of the setpoints entered and, in addition, on the predetermined pump flow that can be conveyed.
  • this leads to a weighting of the individual consumers and ensures that B. for safety reasons - important consumers always have an adequate oil flow.
  • the setpoints are reduced in advance if the specified pump flow that can be conveyed is expected to be exceeded on the basis of the input setpoint signals.
  • a control pump 1 is adjusted hydraulically.
  • a hydraulic valve (spring-loaded pressure compensator) 2 which detects the pump flow, is used for hydraulic adjustment.
  • the pressure compensator 2 is given on the one hand pump pressure and on the other hand the highest consumer pressure together with a spring load by spring 15 via a cascade of shuttle valves 3.
  • the pump 1 loads several consumers 4 ', 4 ⁇ , 4 ′′′.
  • Each consumer 4 is first a pressure control valve (pressure compensator, differential pressure compensator) 5 ';5 ⁇ ; 5 ′′′ upstream.
  • Characterized a constant pressure difference is set on the individual control valve 6, so that a load-independent, the control proportional setting of the respective consumer 4 ';4 ⁇ ; 4 utiliseen supplied volume flow (consumer flow) is possible.
  • the consumer current is therefore only dependent on signals a and b, with which the individual control valves are activated. As long as these signals are constant remain, the consumer current remains constant. However, this only applies on the condition that the control pump can provide a pump current sufficient for all consumers.
  • the control pump 1 is adjusted by an actuator 7.
  • the adjusting member 7 is a cylinder in which a piston with piston rod 17 is movable.
  • the piston adjusts the position of the rotor within the control pump, which is only indicated here.
  • the piston 16 is loaded on one side by a spring 18 and by the control pressure in line 19 emitted by the pressure compensator 2. As already described, this control pressure is dependent on the pressure difference between the pump pressure in the pump line 20 and the highest consumer pressure , which is determined by the cascade of shuttle valves 3.
  • the piston 16 is acted upon by the pump pressure in the pump line 20 on its side facing away from the spring 18.
  • the spring 18 and the control pressure 19 act in the sense of increasing the delivery volume of the control pump.
  • the control pump 1 is therefore included in a control circuit and has the function of supplying the manipulated variable to keep the controlled variable constant: pressure difference between the highest consumer pressure and the pump pressure.
  • the adjustment path with which the control pump 1 is adjusted by means of the actuator 7 is measured.
  • This adjustment path alpha is measured and given to the control unit 21, which will be described later.
  • the control unit is given a signal that represents the measured pump pressure and is designated P in the following. It goes without saying that both the adjustment value alpha and the pressure P via suitable converters into a form suitable for the control unit, e.g. B. a voltage must be converted.
  • control unit 21 is provided on the one hand with the setpoint input devices 13 ', 13 ⁇ , 13 ′′′ and on the other hand with the setpoint output devices, in particular amplifiers 14', 14 ⁇ , 14 ′′′.
  • Each output device is connected with its output lines A and B to the consumer, which has the same numbering. In order not to disturb the clarity of the circuit diagram, these connecting lines are not drawn.
  • control unit 21 also has the inlets for the adjustment path alpha and the pressure P.
  • the control unit is used to adapt the entered target values to the measured pump current.
  • the same control unit is also used for the hydraulic system according to FIG. 2. A description of FIG. 2 is therefore given first.
  • Three consumers 4 ', 4 ⁇ , 4 ′′′ are fed by a constant hydraulic pump 1.
  • a volume flow control is carried out by means of a pressure differential balance 22.
  • the piston 23 of the pressure differential balance is loaded on one side by a spring 24 and the highest load pressure.
  • the highest load pressure is determined via a cascade of shuttle valves 3.
  • the piston 23 is loaded by the pump pressure.
  • the differential pressure balance is connected to the tank via a bypass channel. By adjusting the piston 23, a constant pressure difference is adjusted. This regulation remains effective until the sum of the consumer flows supplied to the consumers exceeds the maximum pump flow that can be pumped.
  • Each consumer 4 is first a pressure control valve (pressure compensator, differential pressure compensator) 5 ';5 ⁇ ; 5 ′′′ upstream.
  • Each pressure control valve 5 is on the one hand the pressure in front of the associated control valve 6 ', 6 ⁇ , 6 ′′′ (directional control valve) and on the other hand the consumer pressure of the respective consumer 4 abandoned. Characterized a constant pressure difference is set on the individual control valve 6, so that a load-independent, the control proportional setting of the respective consumer 4 ';4 ⁇ ; 4 utiliseen supplied volume flow (consumer flow) is possible.
  • the balance piston of the differential pressure balance has a piston rod 25.
  • the displacement of the piston 23 is measured.
  • the output signal is called alpha.
  • the pump pressure and the displacement of the piston alpha is given to the control unit 21, which has already been described above. Reference is made to this description.
  • the adjustment path alpha is entered into a module 11.
  • a limit value alpha max is specified for module 11. This limit value alpha max can be specified constantly if only the input of the adjustment path is connected to the control unit 21. If the pump pressure P is also connected, further processing follows, which will be discussed later.
  • the measured adjustment path and the limit value alpha max are weighted.
  • the output signal of the module 11 is given to another module 10.
  • This function block 10 produces a positive constant output signal equal to 1 as long as the limit value of the adjustment path alpha max is greater than the measured adjustment path alpha. If the adjustment path alpha exceeds the limit value, the output signal of the function block 10 becomes smaller than 1.
  • the output signal a des decreases Function block 10 or 30, as long as the adjustment range alpha exceeds the limit value and until equilibrium is reached between the two.
  • the output signal of the function block 10, in the following weighting block can be further influenced by connecting the pressure measuring line P to the control unit 21. For this purpose, the measured value of the adjustment path is given to a multiplier 8 together with the final pump pressure.
  • the output signal of the multiplier 8 represents the hydraulic torque of the pump 1.
  • This output signal is related in block 9 to the maximum possible output signal.
  • the output signal of the module 9 is given to a further module 10, by which weighting takes place. The weighting can take place with the pump pressure and / or with the current adjustment path of the control pump. For this purpose, the current adjustment path is again related to the maximum adjustment path via module 11.
  • the output signal of the multiplier 8 is given to the function block 9 via a comparison block 26.
  • the comparison block the current torque pump determined by multiplication is related to the limit value Mmax of the pump, which is constantly specified.
  • the function block 9 now processes the output signal of the comparison block 26 so that it emits an output signal equal to 1 if the current torque is less than the limit value of the torque, and that it emits a time-reducing output signal as long as the currently determined torque is greater than that Limit is.
  • the output signal decreases according to a time-dependent function starting from 1 until equilibrium is reached by reducing the torque.
  • the output signal of the function block 9 is now used to process the maximum travel alpha max, as has already been indicated.
  • a multiplication module 27 is used for this purpose.
  • the limit value of the adjustment path alpha max is predetermined from the outside of this multiplication module, and on the other hand the output signal of the function block 9, which is related to the current torque.
  • the output signal of the multiplication module 27 is in turn given to the comparator 11. This ensures that the delivery rate of the pump is reduced when the predetermined torque is exceeded.
  • a permanently entered limit value of the pump pressure is related to the currently measured pump pressure in a comparator 28 (comparison module).
  • the module 10 now also contains a function module 29 which is controlled by the output signal of the comparator 28 and additionally by a limit value which represents the maximum desired value.
  • These entered quantities are now processed in the function block 29 in such a way that the function block 29 gives an output signal B which is zero as long as the measured pump pressure is less than the limit value Pmax of the pressure and which is equal to the limit value Smax of the setpoints if the measured pump pressure exceeds the limit value Pmax of the pump pressure.
  • the weighting block 10 with its two output signals A of the function block 30 and B of the function block then controls comparators 12 ', 12 ⁇ , 12 ′′′, each one of the valves 6', 6 ⁇ , 6 ′′′ for the individual consumers 4 ', 4 ⁇ , 4 ′′′ are assigned.
  • Each of these comparison elements 12 can be given a different setpoint via the setpoint generator 13 ', 13 ⁇ , 13 13.
  • the output signals of the comparison elements 12 are then via amplifiers 14 ', 14 ⁇ , 14 ′′′ the respective control signals for the magnets a1, b1, a2, b2, a3, b3 of the respective valves 6', 6 ⁇ , 6 ′′′ or the input signals of the actuators , through which the individual directional control valves 6 are controlled, superimposed.
  • the individual consumer 4 ', 4 ⁇ , 4 ′′′ can be supplied Volume flow are reduced so far that the total amount that can be pumped by the pump 1 is not exceeded.
  • the simultaneous detection and direct input of the adjustment path or the swivel angle of the control pump 1 can simultaneously ensure in the weighting module 10 that an adaptation of the current delivery rate to the maximum possible delivery rate takes place simultaneously with the adjustment to the current torque of the pump 1.
  • the current pump pressure P or other operating parameters of the hydraulic system can also be included in the weighting.
  • the comparison elements 12 - as shown in FIG. 13 - are divided into a multiplication module 31 ', 31 ⁇ , 31 ⁇ and a limiting module 32', 32 ⁇ , 32 ′′′.
  • the output signal A of the function block 30 and the setpoint value S1, S2, S3 are given to the multiplication block.
  • the setpoint S set is related to the current displacement of the pressure compensator or the variable displacement pump if the sum of the consumer flows exceeds the limit value of the pump flow.
  • the setpoints are reduced accordingly.
  • the output signal of the multiplication modules 31 is given to the limitation module 32 together with the output signal B of the function module 29, which establishes the relationship to the measured pump pressure.
  • the output signal of the limitation module 32 is limited to the entered limit value Smax of the setpoint.
  • Smax the limit value of the setpoint.
  • a further evaluation of the limit value Smax can be carried out in the sense that either there is no limit at all or the limit value is reduced or increased. This allows priorities to be given to individual consumers. Other consumers can be shut down or treated subordinately if the setpoint values set would lead to the limit value of the pump current being exceeded.
  • a setpoint processing is now additionally shown, which can be used optionally.
  • a setpoint generator 33 can be arranged upstream of the control unit 21.
  • the setpoint generator has a first component 34 for each input setpoint, which is referred to below as a ramp.
  • This ramp means that an abruptly entered setpoint only changes over time. This has the effect that the signal processing and adaptation of the hydraulic system can follow in time even when the setpoint value is entered suddenly and there is no temporary undersupply of the consumers.
  • the output signals of the ramps 34 are then multiplied in multiplication modules 35 by input limit values G1 to G3. These limit values represent a certain percentage of the limit value of the pump current. This results in a weighting of the entered target values in the multiplication modules 35.
  • the output signals of the multiplication modules 35 are fed to a summing element 36 with the output signal P2, which represents the sum of the output signals of the multiplication modules.
  • the signal E2 is given to a function block 37 together with a signal E1.
  • the signal E1 represents the maximum predetermined pump current in a form that is comparable to the signal E2.
  • the two input signals E1 and E2 are connected in the function block 37.
  • the output signal A is equal to 1 as long as the specified limit value of the pump delivery flow is greater than the set and weighted sum of the setpoints.
  • the output signal is equal to the quotient of the limit value and the weighted sum if the weighted sum is greater than the limit value.
  • the output signal of the function block 37 is now given to the multiplication blocks 38 ', 38 38, 38 ′′′.
  • the respective setpoint S1, S2, S3 is multiplied after it has preferably first been passed over the ramps 34 ′, 34 ⁇ , 34 ′′′.
  • the output signal of the multiplication modules 38 represents the respective setpoint given to the control unit 21.
  • This setpoint processing ensures that the setpoint input ensures that the setpoint values do not lead to consumption that far exceeds the specified limit value of the pump current. However, this is only a rough precaution.
  • the inventive superimposition of the adaptation of the consumer flows to the measured pump current ensures that each consumer remains functional within the framework assigned to it.
  • the particular importance of the invention lies in the fact that on the one hand the pump torque is corrected, but that a torque control can be superimposed on this torque control by simultaneously also detecting the speed of the pump or its delivery rate.
  • a control system comes into operation with which the setpoint signals with which the valves 6 are controlled are adapted to the currently measured pump delivery rate, preferably to the weighting of the currently measured pump delivery rate with the maximum predetermined pump delivery rate become.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Control Of Positive-Displacement Pumps (AREA)

Abstract

Dans un système hydraulique, plusieurs consommateurs (4) sont alimentés par une pompe commune, les consommateurs (4) étant commandés par des soupapes de commande (6). Si les flux d'huile demandés dépassent le débit maximum réalisable, il intervient une régulation selon laquelle les signaux de valeur de consigne, par lesquels les soupapes (6) sont pilotées, sont adaptés au débit de pompage mesuré effectivement, de préférence à la pondération du débit de pompage mesuré effectivement avec le débit de pompage maximum prédéterminé.

Claims (8)

  1. Circuit hydraulique dans lequel plusieurs utilisateurs (4) sont alimentés par une pompe (1) commune par l'intermédiaire chacun d'une vanne de commande (6), les débits amenés aux différents utilisateurs (4) étant contrôlés par les vannes de commande (6) associées de telle sorte que le débit de refoulement actuel de la pompe (1) délivré à l'ensemble des utilisateurs (4) soit adapté au débit prédéterminé pouvant être refoulé par la pompe, le débit actuel de la pompe (1) (débit de pompe) étant mesuré et utilisé pour adapter les débits des utilisateurs en cas de dépassement d'une valeur seuil (GP) prédéterminée, caractérisé par le fait qu'on détermine le débit actuel au moyen d'une balance de pression (2, 22) qui est connectée à la conduite de refoulement de la pompe (20) et qui, d'un côté, est sollicitée par la pression de refoulement de la pompe et de l'autre, côté ressort, est sollicitée par la pression maximale de la charge.
  2. Circuit hydraulique selon la revendication 1, caractérisé par le fait qu'il est prévu une balance de pression (22) à trois voies pour régler la différence de pression entre la pression de refoulement de la pompe et la pression maximale de la charge et par le fait que pour mesurer le débit de refoulement actuel, soit on mesure le débit dans la dérivation de la balance de pression (22), soit on mesure le déplacement du piston de ladite balance de pression (22).
  3. Circuit hydraulique selon la revendication 1, caractérisé par le fait que la pompe (1) est une pompe réglable et par le fait que l'on mesure en outre la position de réglage de la pompe réglable.
  4. Circuit hydraulique selon la revendication 3, caractérisé par le fait que la position de réglage de la pompe réglable (1) est réglée en fonction de la différence de pression entre la pression de refoulement de la pompe et la pression maximale de la charge.
  5. Circuit hydraulique selon l'une des revendications précédentes, caractérisé par le fait que l'on utilise en outre, pour l'adaptation des débits des utilisateurs, le produit du débit de refoulement actuel et de la pression de refoulement de la pompe.
  6. Circuit hydraulique selon l'une des revendications précédentes, caractérisé par le fait que l'on utilise en outre, pour l'adaptation des débits des utilisateurs, la pression de refoulement de la pompe.
  7. Circuit hydraulique selon l'une des revendications précédentes, caractérisé par le fait que l'on abaisse en fonction du débit prédéterminé pouvant être refoulé par la pompe et en fonction de la somme des signaux de valeur de consigne réglés le signal de valeur de consigne à partir duquel on active chacune des vannes de commande (6) pour régler le débit d'utilisateur.
  8. Circuit hydraulique selon la revendication 7, caractérisé par le fait qu'avant de réaliser la somme des signaux de valeur de consigne on multiplie chaque signal de valeur de consigne par une valeur limite (GV) qui est prédéterminée pour chacun des utilisateurs.
EP92901394A 1990-12-15 1991-12-14 Systeme hydraulique Expired - Lifetime EP0515639B1 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
DE4040177 1990-12-15
DE4040177 1990-12-15
DE4124792 1991-07-26
DE4124792 1991-07-26
PCT/DE1991/000976 WO1992010685A1 (fr) 1990-12-15 1991-12-14 Systeme hydraulique

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EP0515639A1 EP0515639A1 (fr) 1992-12-02
EP0515639B1 true EP0515639B1 (fr) 1995-03-08

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EP92901394A Expired - Lifetime EP0515639B1 (fr) 1990-12-15 1991-12-14 Systeme hydraulique

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US (1) US5394696A (fr)
EP (1) EP0515639B1 (fr)
JP (1) JPH05504820A (fr)
DE (1) DE59104897D1 (fr)
DK (1) DK0515639T3 (fr)
WO (1) WO1992010685A1 (fr)

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Also Published As

Publication number Publication date
JPH05504820A (ja) 1993-07-22
DK0515639T3 (da) 1995-05-22
DE59104897D1 (de) 1995-04-13
US5394696A (en) 1995-03-07
WO1992010685A1 (fr) 1992-06-25
EP0515639A1 (fr) 1992-12-02

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