EP0505977A1 - Velocity control circuit for hydraulic drives, prefably for hydraulic cylinders - Google Patents

Velocity control circuit for hydraulic drives, prefably for hydraulic cylinders Download PDF

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Publication number
EP0505977A1
EP0505977A1 EP92105043A EP92105043A EP0505977A1 EP 0505977 A1 EP0505977 A1 EP 0505977A1 EP 92105043 A EP92105043 A EP 92105043A EP 92105043 A EP92105043 A EP 92105043A EP 0505977 A1 EP0505977 A1 EP 0505977A1
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EP
European Patent Office
Prior art keywords
drive
control valve
speed
side control
hydraulic
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.)
Granted
Application number
EP92105043A
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German (de)
French (fr)
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EP0505977B1 (en
Inventor
Friedrich Dipl.-Ing. Schwing
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Friedrich Wilhelm Schwing GmbH
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Friedrich Wilhelm Schwing GmbH
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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
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
    • F15B11/044—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the return line, i.e. "meter out"
    • 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
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
    • 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
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
    • F15B11/042—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the feed line, i.e. "meter in"
    • 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
    • F15B2211/30505—Non-return valves, i.e. check valves
    • F15B2211/3051—Cross-check 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
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • 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
    • F15B2211/3122—Special positions other than the pump port being connected to working ports or the working ports being connected to the return line
    • F15B2211/3127—Floating position connecting the working ports and the return line
    • 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
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40515—Flow control characterised by the type of flow control means or valve with variable throttles or orifices
    • 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
    • F15B2211/40—Flow control
    • F15B2211/41—Flow control characterised by the positions of the valve element
    • F15B2211/411—Flow control characterised by the positions of the valve element the positions being discrete
    • 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
    • F15B2211/40—Flow control
    • F15B2211/42—Flow control characterised by the type of actuation
    • F15B2211/428—Flow control characterised by the type of actuation actuated by fluid 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
    • F15B2211/40—Flow control
    • F15B2211/455—Control of flow in the feed line, i.e. meter-in control
    • 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
    • F15B2211/40—Flow control
    • F15B2211/46—Control of flow in the return line, i.e. meter-out control
    • 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
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
    • F15B2211/50518—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using pressure relief 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
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5153—Pressure control characterised by the connections of the pressure control means in the circuit being connected to an output member and a 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
    • F15B2211/50—Pressure control
    • F15B2211/55—Pressure control for limiting a pressure up to a maximum pressure, e.g. by using a pressure relief 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
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/635—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements
    • F15B2211/6355—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements having valve means
    • 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
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7051—Linear output members
    • F15B2211/7053—Double-acting output members
    • 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
    • F15B2211/75—Control of speed of the output member
    • 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
    • F15B2211/77—Control of direction of movement of the output member
    • F15B2211/7741—Control of direction of movement of the output member with floating mode, e.g. using a direct connection between both lines of a double-acting cylinder

Definitions

  • the invention relates to a circuit arrangement for speed control of hydraulic drives according to the preamble of claim 1.
  • the invention relates to hydraulic drives in which the speed derived from them depends on the amount of hydraulic medium supplied to the drive in the unit of time, the swallowing amount of the drive generally not being variable.
  • the invention relates in particular to so-called thrust piston gears, which generate the kinetic energy via a reversible piston of a hydraulic working cylinder. The invention is therefore preferably described below using this application.
  • hydraulic thrust piston gears are started at a constant speed from a standstill and fully braked from the respective speed.
  • the arrangement of a 4/3-way control valve spool is sufficient, which changes the pressure and the tank line in both extreme positions, but in the middle position switches the pump contained in the hydraulic pressure generator to circulation, ie switches to the tank of the hydraulic medium. With such drives, the piston speeds are approximately constant in both directions.
  • Is in one direction or another or in Both directions of movement of the thrust piston are driven by the load, on the outflow side of a load holding valve, that is to say a hydraulically unlockable check or brake valve, in order to prevent the thrust piston from going through and to run it in the cylinder at a speed corresponding to the predetermined amount of the conveyed hydraulic medium allow.
  • a load holding valve that is to say a hydraulically unlockable check or brake valve
  • Such also known as black / white control hydraulic circuit arrangement are provided, for example, for the drive cylinders of pivoting arms or masts, which, for. B. as a crane or concrete placing booms have hydraulically driven joints that connect the mast section with each other.
  • the drive cylinders are regularly under the load of the mast section emanating from the joint in question and, if appropriate, the loads acting on them, e.g. B. a concrete delivery line.
  • the black / white control has the property that it fully loads the drives. This results in jerky starting and braking of the joint movement. Apart from the associated increased wear, the mast often vibrates as a result, which can cause mechanical stress on the components and the like. U. dangerous reinforcement, which can result in accidents and damage.
  • a nozzle is installed in the inlet and outlet between the control valve and the working cylinder, the nozzles being matched to one another in such a way that the nozzle allows the amount of the hydraulic medium intended for this circuit to pass through at maximum load including the barrier pressure load; on the other hand, the nozzle in the inlet is set so that when the hydraulic quantity determined for this circuit passes, the required unlocking pressure prevails behind the nozzle, while the safety pressure in front of the nozzle is just being reached.
  • the two nozzles are therefore matched to one another in this way.
  • a proportional control of this type uses a control valve in front of the drive which electromagnetically changes the opening cross section of fine control grooves, which is approximately proportional to the speed.
  • the electromagnetic setting of the control valve and thus that of its pilot control grooves presupposes a potentiometer circuit which considerably increases the complexity of the electrical assemblies, which is already excessive due to such a control valve.
  • such circuit arrangements are sensitive to contamination because of the fine control grooves, so that frequent malfunctions are inevitable, which mostly occur due to jamming of the valve.
  • the handling of such controls via the command switch is difficult because it has to be adjusted very sensitively.
  • the strictly proportional control is abandoned in favor of a graduated proportionality, the stages of which are given by the nozzle pairs, the step jumps being able to be increased or decreased almost as desired and matched to the requirements of the individual case by the choice of the number of nozzle pairs and the stage differences .
  • the respective speed gradations are selected and set via the command switch, which can therefore be provided with a corresponding number of switching positions.
  • the invention has the advantage that it enables the speed differences corresponding to the proportionality, which can be used arbitrarily and. a. also to start and brake the hydraulic drive smoothly by switching on the command switch until the desired maximum speed or the drive has come to a standstill.
  • the embodiment according to claim 2 is recommended.
  • B. can be realized with a conventional 5/3-way valve. If there is a switching fault on the drive-side control valve spool, the drive is not at risk. Rather, the circuit arrangement according to the invention then becomes a black / white control at the speed level set on the drive-side control valve switch until the fault is eliminated.
  • the new circuit arrangement can be operated mechanically.
  • the simplest embodiment of the invention is characterized by the features of claim 4. Two mechanical switches are required, one of which is used for starting and braking the drive, while the other switch preselects the drive direction or the drive is stopped .
  • circuit arrangement according to the invention is recommended, which can be operated remotely over large distances.
  • Such an embodiment is the subject of claim 5. This also eliminates the difficulties associated with switching forces to be applied mechanically when switching through the drive-side control valve switch. Rather, this can be set mechanically / magnetically.
  • the circuit arrangement shown there serves for speed control of the piston of a hydraulic drive, which according to the exemplary embodiment shown is designed as a thrust piston gear (Z).
  • a load holding valve is assigned to the piston annulus and the piston surface area.
  • Each of the valves can be hydraulically unlocked via lines shown in dash-dot lines.
  • the lines of the load holding valves (1, 2) shown in solid lines serve alternately as inflow and outflow lines and end at a drive-side control valve spool (V1).
  • this control valve spool (V1) has three switching positions designated (I-III).
  • each switching position has eight paths (two on the cylinder side and six on the nozzle side). Two of the nozzle-side paths are continuous to the cylinder side, the other paths are blocked.
  • the switching positions differ from each other in the arrangement of the passages. These are selected so that in each of the switching positions one of three nozzles (1 to 3 or 1 'to 3') connected in parallel is assigned.
  • the nozzles are assigned to one another in pairs in accordance with their atomic numbers.
  • the passages are on the nozzles (1, 1 '), in the switching position (II) on the nozzles (2, 2') and in the switching position (III) on the nozzles (3 and 3 ' ) switched.
  • Each of these nozzles has a predetermined opening which is assigned to a speed level of the drive.
  • the switching position (1) the nozzles (1, 1 ') with the smallest bore and therefore the lowest speed assigned to the drive (Z) are switched through, while with the switching position (2) an average speed with the nozzles (2, 2' ) is guaranteed and reaches the highest speed in the switch position (3) because the nozzles (3, 3 ') let through the greatest amount of the hydraulic medium.
  • the drive-side control slide (V1) is preceded by a pump-side control slide (V2).
  • the nozzles connected in parallel (1 to 3 or 1 'to 3') are located in the drain lines of this control slide, which is likewise designed as a directional control valve.
  • the control valve on the pump side (V2) is switched mechanically and magnetically and shuts off the piston chambers of the cylinder (2) in the middle switching position.
  • the passages for the forward and return flow of the piston are arranged in the two other switching positions of the control valve spool (V2) on the pump side.
  • a control valve spool (V3) is provided, which is used for pilot control of the control valve spool (V1). It is designed as a 4/3-way valve and is switched magnetically. In its middle position, it switches the control valve spool (V1) on the drive side to switch position (2), which is maintained with the help of the springs arranged on both sides. In the two outer positions, the switching stages (I and III) are reached, which is done against the force of a bias spring.
  • a command switch (K) is provided for actuating the circuit arrangement.
  • a switching element can e.g. B. are turned clockwise, whereby the piston annulus is acted on, which is evident from the fact that in all switching positions (A, B, C) the switching relay (S) is always switched, which the pump-side control valve (V2) in the (S) Position switches which determines the choice of the direction of movement, in this case "lowering".
  • the passage of the switching positions (A, B, C) corresponds to the direction of increasing speed of the drive, in this case the piston of the cylinder (Z).
  • the switching positions (A, B, C) of the switching element are necessarily connected to the valve positions (I, II, III) of the drive-side control valve (V1) because the relay (VL) and thus the pilot valve ( V3) are actuated so that the control pressure (P St ) acts on the control valve (V1) so that it assumes position (I) at the lowest speed, and analogously with switching position (C) the relay (VR) and thus the pilot valve (V3) are actuated so that the control pressure (P St ) is applied to the control valve (V1) so that it assumes the position (III) at the same speed and last but not least at switching positions (B) by not actuating the pilot valve (V3) and thus, even when the control valve (V1) is not acted upon, it reaches the spring-centered position (II) of the same average speed.
  • the switching element of the command switch (K) can also be in the opposite direction, ie. H. Adjust counterclockwise, whereby the piston chamber is acted on, which is evident from the fact that in all switching positions (A ', B', C ') a switching relay (H) is always switched, which switches the pump-side control valve (V2) into the (H ) Position switches, which defines the direction of movement, in this case "lifting".
  • the speed is graded analogously to the passage of the switching positions (A, B, C) described above.
  • FIG. 2 differs from the embodiment of FIG. 1 in its mechanical design.
  • the control valve spool (V1 and V2) are required because the command switch (K) is mechanical, i. H. is directly connected to the switching element of the drive-side control slide.
  • Its mechanical output has a detent for each speed level or its switching position in the drive-side control valve spool (V1), the notch assigned to the switching stage (II) being identified by a dash.
  • a second mechanical command switch (K1) is provided on the control valve spool (V2) on the pump side. Its output also has detents in accordance with the number of its switching positions, the middle switching position being identified in FIG. 2.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Other Liquid Machine Or Engine Such As Wave Power Use (AREA)

Abstract

In a velocity control circuit for hydraulic drives, preferably for hydraulic cylinders, in which one drive velocity each, selected and set via a command switch, is allocated to different quantities of the hydraulic medium, the invention is characterised in that, in the inflow and outflow line of the drive (Z), in each case a nozzle (1 to 3; 1' to 3') is allocated to a stage of the drive velocity, and nozzles (1, 1'; 2, 2'; 3, 3') allocated to the same velocity stage are each allocated to a connect-through position of a drive-side distributing slide valve (V1), and the medium passes through the connect-through positions (I to III) of the distributing slide valve (V1) in the direction of increasing or falling velocity graduations in one actuating direction each of the command switch (K). <IMAGE>

Description

Die Erfindung betrifft eine Schaltungsanordnung zur Geschwindigkeitssteuerung von hydraulischen Antrieben gemäß dem Oberbegriff des Anspruches 1.The invention relates to a circuit arrangement for speed control of hydraulic drives according to the preamble of claim 1.

Die Erfindung bezieht sich dabei auf hydraulische Antriebe, bei denen die von ihnen abgeleitete Geschwindigkeit von der Menge des in der Zeiteinheit dem Antrieb zugeführten hydraulischen Mediums abhängt, wobei die Schluckmenge des Antriebes im allgemeinen nicht veränderlich ist. Das gilt für verschiedene bekannte hydraulische Antriebe, die in der Regel einfach ausgebildet sind. In der Praxis dienen solche Antriebe unterschiedlichen Zwecken, z. B. der Zuführung von Bewegungsenergie an Drehwerken von Baggern und Kränen. Die Erfindung bezieht sich insbesondere auf sogenannte Schubkolbengetriebe, welche die Bewegungsenergie über einen umsteuerbaren Kolben eines hydraulischen Arbeitszylinders erzeugen. Die Erfindung wird daher im folgenden bevorzugt anhand dieser Anwendung beschrieben.The invention relates to hydraulic drives in which the speed derived from them depends on the amount of hydraulic medium supplied to the drive in the unit of time, the swallowing amount of the drive generally not being variable. This applies to various known hydraulic drives, which are generally simple in design. In practice, such drives serve different purposes, e.g. B. the supply of kinetic energy to the slewing gear of excavators and cranes. The invention relates in particular to so-called thrust piston gears, which generate the kinetic energy via a reversible piston of a hydraulic working cylinder. The invention is therefore preferably described below using this application.

Im allgemeinen werden hydraulische Schubkolbengetriebe mit konstanter Geschwindigkeit aus dem Stand heraus angefahren und aus der jeweiligen Geschwindigkeit auch voll abgebremst. In diesen Fällen genügt die Anordnung eines 4/3-Wegesteuerventilschiebers, welcher in beiden Extremstellungen die Druck- und die Tankleitung wechselt, in der Mittelstellung aber die im hydraulischen Druckerzeuger enthaltene Pumpe auf Umlauf, d. h. auf den Tank des hydraulischen Mediums schaltet. Bei solchen Antrieben sind die Kolbengeschwindigkeiten in beiden Richtungen annähernd konstant. Ist in der einen oder anderen Richtung oder in beiden Bewegungsrichtungen der Schubkolben von der Last angetrieben, bedarf es auf der Abflußseite eines Lasthalteventils, d. h. eines hydraulisch entsperrbaren Rückschlag- bzw. Bremsventils, um das Durchgehen des Schubkolbens zu verhindern und ihn mit einer der vorgegebenen Menge des geförderten hydraulischen Mediums entsprechenden Geschwindigkeit im Zylinder laufen zu lassen.In general, hydraulic thrust piston gears are started at a constant speed from a standstill and fully braked from the respective speed. In these cases, the arrangement of a 4/3-way control valve spool is sufficient, which changes the pressure and the tank line in both extreme positions, but in the middle position switches the pump contained in the hydraulic pressure generator to circulation, ie switches to the tank of the hydraulic medium. With such drives, the piston speeds are approximately constant in both directions. Is in one direction or another or in Both directions of movement of the thrust piston are driven by the load, on the outflow side of a load holding valve, that is to say a hydraulically unlockable check or brake valve, in order to prevent the thrust piston from going through and to run it in the cylinder at a speed corresponding to the predetermined amount of the conveyed hydraulic medium allow.

Solche auch als Schwarz/Weiß-Steuerung bezeichnete hydraulische Schaltungsanordnung sind beispielsweise für die Antriebszylinder von schwenkbaren Auslegern oder Masten vorgesehen, welche z. B. als Kran oder Betonverteilermasten hydraulisch angetriebene Gelenke aufweisen, die die Mastsektion miteinander verbinden. Hierbei stehen die Antriebszylinder regelmäßig unter der Last der von dem betreffenden Gelenk ausgehenden Mastsektion und gegebenenfalls der auf diese wirkenden Belastungen, z. B. einer Betonförderleitung. Die Schwarz/Weiß-Steuerung hat die Eigenschaft, daß sie die Antriebe voll beaufschlagt. Das hat ein ruckartiges Starten und Abbremsen der Gelenkbewegung zur Folge. Abgesehen von dem damit verbundenen erhöhten Verschleiß gerät der Mast dadurch häufig in Schwingungen, welche die mechanische Belastung der Bauteile u. U. gefährlich verstärken, was Unfälle und Schäden zur Folge haben kann.Such also known as black / white control hydraulic circuit arrangement are provided, for example, for the drive cylinders of pivoting arms or masts, which, for. B. as a crane or concrete placing booms have hydraulically driven joints that connect the mast section with each other. Here, the drive cylinders are regularly under the load of the mast section emanating from the joint in question and, if appropriate, the loads acting on them, e.g. B. a concrete delivery line. The black / white control has the property that it fully loads the drives. This results in jerky starting and braking of the joint movement. Apart from the associated increased wear, the mast often vibrates as a result, which can cause mechanical stress on the components and the like. U. dangerous reinforcement, which can result in accidents and damage.

Es ist bereits versucht worden, solchen Nachteilen entgegenzuwirken. Einer dieser Vorschläge läuft darauf hinaus, die beschriebene Schwarz/Weiß-Schaltung durch je eine Drossel bzw. Blende mit konstantem Durchschlußquerschnitt (Düse) zu ergänzen, wodurch die nachteiligen Schwingungsstöße ausgeschaltet werden. Solche Schaltungsanordnungen erlauben es auch, mit einem Druckerzeuger, der eine Pumpe mit konstantem Förderstrom aufweist, mehrere hydraulische Kreise mit jeweils unterschiedlichen Teilmengen zu speisen, was von den jeweils in den Kreisen herrschenden Betriebsdrücken unabhängig ist. Dazu ist im Zu- und Ablauf zwischen Steuerventil und Arbeitszylinder jeweils eine Düse eingebaut, wobei die Düsen so aufeinander abgestimmt sind, daß die Düse im Ablauf bei maximaler Last einschließlich der Sperrdrucklast die für diesen Kreis bestimmte Menge des hydraulischen Mediums durchläßt; dagegen ist die Düse im Zulauf so eingestellt, daß bei Durchlaß der für diesen Kreis bestimmten Hydraulikmenge hinter der Düse der erforderliche Entsperrdruck herrscht, während vor der Düse der Sicherheitsdruck gerade erreicht wird. Die beiden Düsen sind demnach aufeinander in dieser Weise abgestimmt.Attempts have been made to counteract such disadvantages. One of these suggestions amounts to supplementing the described black / white circuit with a choke or orifice with a constant flow cross-section (nozzle), whereby the disadvantageous vibrations are eliminated. Such circuit arrangements also make it possible to supply a plurality of hydraulic circuits, each with different partial quantities, with a pressure generator that has a pump with a constant flow rate, which is independent of the operating pressures prevailing in the circles. For this purpose, a nozzle is installed in the inlet and outlet between the control valve and the working cylinder, the nozzles being matched to one another in such a way that the nozzle allows the amount of the hydraulic medium intended for this circuit to pass through at maximum load including the barrier pressure load; on the other hand, the nozzle in the inlet is set so that when the hydraulic quantity determined for this circuit passes, the required unlocking pressure prevails behind the nozzle, while the safety pressure in front of the nozzle is just being reached. The two nozzles are therefore matched to one another in this way.

Während bei einer solchen Schaltungsanordnung lediglich die Schwingungsstöße vermindert werden, lassen sich mit Proportionalsteuerungen kontinuierliche Geschwindigkeitsänderungen der von dem Antrieb abgeleiteten Geschwindigkeit herbeiführen, was ein wesentlich besseres Mittel zur Minderung der Anfahr- und Bremsstöße darstellt. Eine Proportionalsteuerung dieser Art benutzt vor dem Antrieb ein Steuerventil, das elektromagnetisch den Öffnungsquerschnitt von Feinsteuernuten ändert, welcher annährend geschwindigkeitsproportional ist. Die elektromagnetische Einstellung des Steuerventils und damit die seiner Vorsteuernuten setzt eine Potentiometerschaltung voraus, die den durch ein derartiges Steuerventil an sich schon überhöhten Aufwand durch die elektrischen Baugruppen noch erheblich vergrößert. Außerdem sind solche Schaltungsanordnungen wegen der Feinsteuernuten verschmutzungsempfindlich, so daß häufige Störungen unvermeidlich sind, die meistens durch Verklemmungen des Ventils zustandekommen. Darüberhinaus ist die Handhabung solcher Steuerungen über den Kommandoschalter schwierig, weil dieser sehr feinfühlig verstellt werden muß.While such a circuit arrangement only reduces the vibration surges, proportional controls can be used to bring about continuous changes in the speed of the speed derived from the drive, which is a much better means of reducing the starting and braking shocks. A proportional control of this type uses a control valve in front of the drive which electromagnetically changes the opening cross section of fine control grooves, which is approximately proportional to the speed. The electromagnetic setting of the control valve and thus that of its pilot control grooves presupposes a potentiometer circuit which considerably increases the complexity of the electrical assemblies, which is already excessive due to such a control valve. In addition, such circuit arrangements are sensitive to contamination because of the fine control grooves, so that frequent malfunctions are inevitable, which mostly occur due to jamming of the valve. In addition, the handling of such controls via the command switch is difficult because it has to be adjusted very sensitively.

Die Erfindung geht einen anderen Weg, der in dem Anspruch 1 wiedergegeben ist. Weitere Merkmale der Erfindung sind Gegenstand der Unteransprüche.The invention takes a different approach, which is set out in claim 1. Further features of the invention are the subject of the dependent claims.

Gemäß der Erfindung wird die streng proportionale Steuerung zugunsten einer abgestuften Proportionalität aufgegeben, deren Stufen durch die Düsenpaare gegeben sind, wobei durch die Wahl der Anzahl der Düsenpaare und der Stufendifferenzen nahezu beliebig und abgestimmt auf die Erfordernisse des Einzelfalles die Stufensprünge vergrößert bzw. vermindert werden können. Die jeweiligen Geschwindigkeitsabstufungen werden über den Kommandoschalter angewählt und eingestellt, der deshalb mit einer entsprechenden Anzahl von Schaltsstellungen versehen sein kann.According to the invention, the strictly proportional control is abandoned in favor of a graduated proportionality, the stages of which are given by the nozzle pairs, the step jumps being able to be increased or decreased almost as desired and matched to the requirements of the individual case by the choice of the number of nozzle pairs and the stage differences . The respective speed gradations are selected and set via the command switch, which can therefore be provided with a corresponding number of switching positions.

Die Erfindung hat den Vorteil, daß sie die der Proportionalität entsprechenden Geschwindigkeitsdifferenzen ermöglicht, die sich beliebig nutzen lassen u. a. auch um den hydraulischen Antrieb stoßfrei anzufahren und abzubremsen, indem man den Kommandoschalter weiterschaltet, bis die gewünschte Höchstgeschwindigkeit oder der Stillstand des Antriebes erreicht sind.The invention has the advantage that it enables the speed differences corresponding to the proportionality, which can be used arbitrarily and. a. also to start and brake the hydraulic drive smoothly by switching on the command switch until the desired maximum speed or the drive has come to a standstill.

Wenn der Antrieb in dieser Weise geschaltet, beispielsweise sein Anfahr- oder sein Abbremsvorgang verbessert werden soll, empfiehlt sich die Ausführungsform nach Anspruch 2. Der pumpenseitige Steuerschieber kann z. B. mit einem üblichen 5/3-Wegeventil verwirklicht werden. Wenn sich dann eine Durchschaltstörung am antriebsseitigen Steuerventilschieber einstellt, ist der Antrieb nicht gefährdet. Vielmehr wird dann die erfindungsgemäße Schaltungsanordnung zu einer Schwarz/Weiß-Steuerung auf der am antriebsseitigen Steuerventilschalter eingestellten Geschwindigkeitsstufe, bis die Störung behoben ist.If the drive is switched in this way, for example, its starting or braking operation is to be improved, the embodiment according to claim 2 is recommended. B. can be realized with a conventional 5/3-way valve. If there is a switching fault on the drive-side control valve spool, the drive is not at risk. Rather, the circuit arrangement according to the invention then becomes a black / white control at the speed level set on the drive-side control valve switch until the fault is eliminated.

Aus Sicherheitsgründen empfiehlt es sich, die Merkmale des Anspruches 3 zu verwirklichen. Dadurch wird gewährleistet, daß der Antrieb nur mit der niedrigsten Geschwindigkeitsstufe angefahren und von der höchsten Geschwindigkeitsstufe aus abgebremst werden kann.For security reasons, it is advisable to implement the features of claim 3. This ensures that the drive can only be started at the lowest speed level and braked from the highest speed level.

Die neue Schaltungsanordnung läßt sich mechanisch betätigen. In diesem Falle kennzeichnet sich die einfachste Ausführung der Erfindung mit den Merkmalen des Anspruches 4. Hierbei sind zwei mechanische Schalter erforderlich, von denen der eine zum Anfahren und Abbremsen des Antriebes dient, während mit dem anderen Schalter die Antriebsrichtung vorgewählt bzw. der Antrieb stillgesetzt wird.The new circuit arrangement can be operated mechanically. In this case, the simplest embodiment of the invention is characterized by the features of claim 4. Two mechanical switches are required, one of which is used for starting and braking the drive, while the other switch preselects the drive direction or the drive is stopped .

Im allgemeinen empfiehlt sich jedoch eine Ausführungsform der erfindungsgemäßen Schaltungsanordnung, welche über größere Entfernungen fernbedienbar ist. Eine solche Ausführungsform ist Gegenstand des Anspruches 5. Hierbei entfallen auch die mit mechanisch aufzubringenden Schaltkräften verbundenen Schwierigkeiten beim Durchschalten des antriebsseitigen Steuerventilsschalters. Diese kann vielmehr mechanisch/magnetisch gestellt werden.In general, however, an embodiment of the circuit arrangement according to the invention is recommended, which can be operated remotely over large distances. Such an embodiment is the subject of claim 5. This also eliminates the difficulties associated with switching forces to be applied mechanically when switching through the drive-side control valve switch. Rather, this can be set mechanically / magnetically.

Im folgenden wird die Erfindung anhand der Zeichnungen näher erläutert; es zeigen

Fig. 1
das mechanische elektrische Schaltbild einer ersten Ausführungsform der erfindungsgemäßen Schaltungsanordnung und
Fig. 2
eine mechanische Ausführung der neuen Schaltungsanordnung in der Fig. 1 entsprechender Darstellung.
The invention is explained in more detail below with reference to the drawings; show it
Fig. 1
the mechanical electrical circuit diagram of a first embodiment of the circuit arrangement according to the invention and
Fig. 2
a mechanical design of the new circuit arrangement in FIG. 1 corresponding representation.

Gemäß der Darstellung nach Fig. 1 dient die dort wiedergegebene Schaltungsanordnung zur Geschwindigkeitssteuerung des Kolbens eines hydraulischen Antriebes, der gemäß dem dargestellten Ausführungsbeispiel als Schubkolbengetriebe (Z) ausgeführt ist. Je ein Lasthalteventil ist dem Kolbenringraum und dem Kolbenflächenraum zugeordnet. Jedes der Ventile ist über strichpunktiert wiedergegebene Leitungen hydraulisch entsperrbar. Die ausgezogen wiedergegebenen Leitungen der Lasthalteventile (1, 2) dienen wechselseitig als Zu- bzw. Abflußleitung und enden an einem antriebsseitigen Steuerventilschieber (V1).1, the circuit arrangement shown there serves for speed control of the piston of a hydraulic drive, which according to the exemplary embodiment shown is designed as a thrust piston gear (Z). A load holding valve is assigned to the piston annulus and the piston surface area. Each of the valves can be hydraulically unlocked via lines shown in dash-dot lines. The lines of the load holding valves (1, 2) shown in solid lines serve alternately as inflow and outflow lines and end at a drive-side control valve spool (V1).

Dieser Steuerventilschieber (V1) hat gemäß dem dargestellten Ausführungsbeispiel drei mit (I-III) bezeichnete Schaltpositionen. Jede Schaltposition hat gemäß der dargestellten Ausführungsform acht Wege (zwei zylinderseitig und sechs düsenseitig). Jeweils zwei der düsenseitigen Wege sind zur Zylinderseite durchgängig, die weiteren Wege sind gesperrt. Die Schaltpositionen unterscheiden sich voneinander durch die Anordnung der Durchgänge. Diese sind so gewählt, daß in jeder der Schaltpositionen jeweils einer von drei parallel geschalteten Düsen (1 bis 3 bzw. 1' bis 3') zugeordnet ist. Entsprechend ihren Ordnungszahlen sind die Düsen paarweise einander zugeordnet. In der Schaltposition (I) sind die Durchgänge auf die Düsen (1, 1'), in der Schaltposition (II) auf die Düsen (2, 2') und in der Schaltposition (III) auf die Düsen (3 bzw. 3') geschaltet. Jede dieser Düsen hat eine vorgegebene Öffnung, die einer Geschwindigkeitsstufe des Antriebes zugeordnet ist. In der Schaltpostion (1) sind die Düsen (1, 1') mit der kleinsten Bohrung und daher der kleinsten dem Antrieb (Z) zugeordneten Geschwindigkeit durchgeschaltet, während mit der Schaltposition (2) eine mittlere Geschwindigkeit mit den Düsen (2, 2') gewährleistet wird und in der Schaltpostion (3) die größte Geschwindigkeit erreicht wird, weil die Düsen (3, 3') die größte Menge des hydraulischen Mediums durchlassen.According to the exemplary embodiment shown, this control valve spool (V1) has three switching positions designated (I-III). According to the embodiment shown, each switching position has eight paths (two on the cylinder side and six on the nozzle side). Two of the nozzle-side paths are continuous to the cylinder side, the other paths are blocked. The switching positions differ from each other in the arrangement of the passages. These are selected so that in each of the switching positions one of three nozzles (1 to 3 or 1 'to 3') connected in parallel is assigned. The nozzles are assigned to one another in pairs in accordance with their atomic numbers. In the switching position (I) the passages are on the nozzles (1, 1 '), in the switching position (II) on the nozzles (2, 2') and in the switching position (III) on the nozzles (3 and 3 ' ) switched. Each of these nozzles has a predetermined opening which is assigned to a speed level of the drive. In the switching position (1) the nozzles (1, 1 ') with the smallest bore and therefore the lowest speed assigned to the drive (Z) are switched through, while with the switching position (2) an average speed with the nozzles (2, 2' ) is guaranteed and reaches the highest speed in the switch position (3) because the nozzles (3, 3 ') let through the greatest amount of the hydraulic medium.

In dem in Fig. 1 wiedergegebenen Ausführungsbeispiel ist dem antriebsseitigen Steuerschieber (V1) ein pumpenseitiger Steuerschieber (V2) vorgeschaltet. In den Abflußleitungen dieses ebenfalls als Wegeventil ausgebildeten Steuerschiebers liegen die parallel geschalteten Düsen (1 bis 3 bzw. 1' bis 3'). Der pumpenseitige Steuerschieber (V2) wird mechanisch magnetisch geschaltet und sperrt in der mittleren Schaltposition die Kolbenräume des Zylinders (2) ab. In den beiden weiteren Schaltpositionen des pumpenseitigen Steuerventilschiebers (V2) sind die Durchgänge für den Vor- und Rücklauf des Kolbens angeordnet.In the exemplary embodiment shown in FIG. 1, the drive-side control slide (V1) is preceded by a pump-side control slide (V2). The nozzles connected in parallel (1 to 3 or 1 'to 3') are located in the drain lines of this control slide, which is likewise designed as a directional control valve. The control valve on the pump side (V2) is switched mechanically and magnetically and shuts off the piston chambers of the cylinder (2) in the middle switching position. The passages for the forward and return flow of the piston are arranged in the two other switching positions of the control valve spool (V2) on the pump side.

Ferner ist im Ausführungsbeispiel der Fig. 1 ein Steuerventilschieber (V3) vorgesehen, welcher zur Vorsteuerung des Steuerventilschiebers (V1) dient. Er ist als 4/3-Wegeventil ausgeführt und wird magnetisch geschaltet. In seiner mittleren Stellung schaltet er den antriebsseitigen Steuerventilschieber (V1) auf die Schaltstellung (2), die mit Hilfe der beiderseitg angeordneten Federn eingehalten wird. In den beiden äußeren Stellungen werden die Schaltstufen (I bzw. III) erreicht, was jeweils gegen die Kraft einer Vorspannfeder geschieht.Furthermore, in the exemplary embodiment in FIG. 1, a control valve spool (V3) is provided, which is used for pilot control of the control valve spool (V1). It is designed as a 4/3-way valve and is switched magnetically. In its middle position, it switches the control valve spool (V1) on the drive side to switch position (2), which is maintained with the help of the springs arranged on both sides. In the two outer positions, the switching stages (I and III) are reached, which is done against the force of a bias spring.

In der Schaltungsanordnung nach Fig. 1 ist zur Betätigung der Schaltungsanordnung ein Kommandoschalter (K) vorgesehen. Ein Schaltglied kann z. B. im Urzeigersinn gedreht werden, wodurch der Kolbenringraum beaufschlagt wird, was dadurch ersichtlich ist, daß bei allen Schaltpositionen (A, B, C) immer das Schaltrelais (S) geschaltet ist, welches das pumpenseitige Steuerventil (V2) in die (S)-Stellung schaltet, womit die Wahl der Bewegungsrichtung, in diesem Falle "Senken", festgelegt ist.In the circuit arrangement according to FIG. 1, a command switch (K) is provided for actuating the circuit arrangement. A switching element can e.g. B. are turned clockwise, whereby the piston annulus is acted on, which is evident from the fact that in all switching positions (A, B, C) the switching relay (S) is always switched, which the pump-side control valve (V2) in the (S) Position switches which determines the choice of the direction of movement, in this case "lowering".

Der Durchlauf der Schaltpositionen (A, B, C) entspricht der Richtung ansteigender Geschwindigkeit des Antriebes, in diesem Falle des Kolbens des Zylinders (Z). Dabei sind die Schaltpositionen (A, B, C) des Schaltgliedes mit den Ventilpostionen (I, II, III) des antriebsseitigen Steuerventils (V1) dadurch zwingend verbunden, weil mit der Schaltposition (A) das Relais (VL) und damit das Vorsteuerventil (V3) so betätigt werden, daß der Steuerdruck (PSt) das Steuerventil (V1) so beaufschlagt, daß es die Stellung (I) gleich kleinste Geschwindigkeit einnimmt, und analog mit der Schaltposition (C) das Relais (VR) und damit das Vorsteuerventil (V3) so betätigt werden, daß der Steuerdruck (PSt) das Steuerventil (V1) so beaufschlagt wird, daß es die Position (III) gleich größte Geschwindigkeit einnimmt und nicht zuletzt bei Schaltpositionen (B) durch Nichtbeaufschlagung des Vorsteuerventils (V3) und somit auch durch Nichtbeaufschlagung des Steuerventils (V1) dieses in die federzentrierte Mittelstellung (II) gleich mittlere Geschwindigkeit gelangt.The passage of the switching positions (A, B, C) corresponds to the direction of increasing speed of the drive, in this case the piston of the cylinder (Z). The switching positions (A, B, C) of the switching element are necessarily connected to the valve positions (I, II, III) of the drive-side control valve (V1) because the relay (VL) and thus the pilot valve ( V3) are actuated so that the control pressure (P St ) acts on the control valve (V1) so that it assumes position (I) at the lowest speed, and analogously with switching position (C) the relay (VR) and thus the pilot valve (V3) are actuated so that the control pressure (P St ) is applied to the control valve (V1) so that it assumes the position (III) at the same speed and last but not least at switching positions (B) by not actuating the pilot valve (V3) and thus, even when the control valve (V1) is not acted upon, it reaches the spring-centered position (II) of the same average speed.

Das Schaltglied des Kommandoschalters (K) läßt sich auch in Gegenrichtung, d. h. gegen den Urzeigersinn verstellen, wodurch der Kolbenraum beaufschlagt wird, was dadurch ersichtlich ist, daß bei allen Schaltpositionen (A', B', C') immer ein Schaltrelais (H) geschaltet ist, welches das pumpenseitige Steuerventil (V2) in die (H)-Stellung schaltet, womit die Bewegungsrichtung, in diesem Falle "Heben", festgelegt ist.The switching element of the command switch (K) can also be in the opposite direction, ie. H. Adjust counterclockwise, whereby the piston chamber is acted on, which is evident from the fact that in all switching positions (A ', B', C ') a switching relay (H) is always switched, which switches the pump-side control valve (V2) into the (H ) Position switches, which defines the direction of movement, in this case "lifting".

Die Geschwindigkeitsabstufung erfolgt analog dem Durchlauf der zuvor beschriebenen Schaltpositionen (A, B, C).The speed is graded analogously to the passage of the switching positions (A, B, C) described above.

Das Ausführungsbeispiel nach Fig. 2 unterscheidet sich vom Ausführungsbeispiel nach Fig. 1 durch seine mechanische Ausführung. In diesem Fall werden nur die Steuerventilschieber (V1 und V2) benötigt, weil der Kommandoschalter (K) mechanisch ausgeführt, d. h. unmittelbar mit dem Schaltglied des antriebsseitigen Steuerschiebers verbunden ist. Sein mechanischer Ausgang besitzt für jede Geschwindigkeitsstufe bzw. deren Schaltposition im antriebsseitigen Steuerventilschieber (V1) eine Raste, wobei die der Schaltstufe (II) zugeordnete Raste mit einem Strich bezeichnet ist.The embodiment of FIG. 2 differs from the embodiment of FIG. 1 in its mechanical design. In this case, only the control valve spool (V1 and V2) are required because the command switch (K) is mechanical, i. H. is directly connected to the switching element of the drive-side control slide. Its mechanical output has a detent for each speed level or its switching position in the drive-side control valve spool (V1), the notch assigned to the switching stage (II) being identified by a dash.

Ein zweiter mechanischer Kommandoschalter (K1) ist am pumpenseitigen Steuerventilschieber (V2) vorgesehen. Auch sein Ausgang besitzt entsprechend der Anzahl seiner Schaltpositionen Rasten, wobei die mittlere Schaltstellung in Fig. 2 gekennzeichnet ist.A second mechanical command switch (K1) is provided on the control valve spool (V2) on the pump side. Its output also has detents in accordance with the number of its switching positions, the middle switching position being identified in FIG. 2.

Claims (5)

Schaltungsanordnung zur Geschwindigkeitssteuerung von hydraulischen Antrieben, vorzugsweise hydraulischen Arbeitszylindern, bei der unterschiedlichen Mengen des hydraulischen Mediums je eine Geschwindigkeit des Antriebes zugeordnet ist, die über einen Kommandoschalter gewählt und eingestellt wird, dadurch gekennzeichnet, daß in der Zufluß- und der Ablfußleitung des Antriebes (Z) jeweils eine Düse (1 bis 3; 1' bis 3') einer Stufe der Antriebsgeschwindigkeit zugeordnet ist und derselben Geschwindigkeitsstufe zugeordnete Düsen (1, 1'; 2, 2'; 3, 3') jeweils einer Durchschaltposition eines antriebsseitigen Steuerventilschiebers (V1) zugeordnet sind, dessen Durchschaltposition (I bis III) in Richtung steigender oder fallender Geschwindigkeitsabstufungen bei jeweils einer Betätigungsrichtung des Kommandoschalters (K) durchlaufen werden (Fig. 1).Circuit arrangement for speed control of hydraulic drives, preferably hydraulic working cylinders, in the case of which different amounts of the hydraulic medium are assigned a speed of the drive, which is selected and set via a command switch, characterized in that in the inflow and outflow lines of the drive (Z ) a nozzle (1 to 3; 1 'to 3') is assigned to a stage of the drive speed and nozzles (1, 1 '; 2, 2'; 3, 3 ') assigned to the same speed stage each have a switching position of a drive-side control valve spool (V1 ) are assigned, the switching position (I to III) of which are traversed in the direction of increasing or decreasing speed gradations with each actuation direction of the command switch (K) (FIG. 1). Schaltungsanordnung nach Anspruch 1, dadurch gekennzeichnet, daß zur Wahl der Antriebsrichtung dem antriebsseitigen Steuerventilschieber (V1) ein pumpenseitiger Steuerventilschieber (V2) vorgeschaltet ist, in dessen stromabwärtsgelegene Druck- und Tankleitung die Düsen (1 bis 3; 1' bis 3') in paralleler Anordnung eingeschaltet sind.Circuit arrangement according to claim 1, characterized in that a pump-side control valve spool (V2) is connected upstream of the drive-side control valve spool (V1) to select the drive direction, the nozzles (1 to 3; 1 'to 3') in parallel in the downstream pressure and tank line Arrangement are switched on. Schaltungsanordnung nach einem der Ansprüche 1 oder 2, dadurch gekennzeichnet, daß der antriebsseitige Steuerventilschieber (V1) in die Schaltposition (3) der niedrigsten Geschwindigkeitsstufe vorgespannt ist und die folgende Geschwindigkeitsstufen (II, I) gegen die Vorspannung schaltbar sind.Circuit arrangement according to one of claims 1 or 2, characterized in that the drive-side control valve slide (V1) in the switching position (3) of the lowest speed level is biased and the following speed levels (II, I) can be switched against the bias. Schaltungsanordnung nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß der Kommandoschalter (K) mit dem antriebsseitigen Steuerventilschieber (V1) mechanisch verbunden ist und ein weiterer Schalter (K1), der mit dem pumpenseitigen Steuerventilschieber (V2) mechanisch verbunden ist vorgesehen ist.Circuit arrangement according to one of claims 1 to 3, characterized in that the command switch (K) is mechanically connected to the drive-side control valve slide (V1) and a further switch (K1) which is mechanically connected to the pump-side control valve slide (V2) is provided. Schaltungsanordnung nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß der antriebsseitige Steuerventilschieber (V1) vorgesteuert ist und ein Kommandoschalter (K) in jeder von zwei Betätigungsrichtungen Schaltpositionen (A bis C; A' bis C') aufweist, in denen jeweils einer Geschwindigkeitsstufe (I bis III) über das Vorsteuerventil (V3) und einer Antriebsrichtung über den pumpenseitigen Steuerventilschieber (V2) angewählt ist.Circuit arrangement according to one of claims 1 to 3, characterized in that the drive-side control valve spool (V1) is pilot-controlled and a command switch (K) has switching positions (A to C; A 'to C') in each of two operating directions, in each of which one Speed level (I to III) is selected via the pilot valve (V3) and a drive direction via the pump-side control valve spool (V2).
EP92105043A 1991-03-25 1992-03-24 Velocity control circuit for hydraulic drives, prefably for hydraulic cylinders Expired - Lifetime EP0505977B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4109754 1991-03-25
DE4109754 1991-03-25

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EP0505977A1 true EP0505977A1 (en) 1992-09-30
EP0505977B1 EP0505977B1 (en) 1995-05-24

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EP92105043A Expired - Lifetime EP0505977B1 (en) 1991-03-25 1992-03-24 Velocity control circuit for hydraulic drives, prefably for hydraulic cylinders

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US (1) US5325761A (en)
EP (1) EP0505977B1 (en)
JP (1) JPH0571504A (en)
KR (1) KR920019060A (en)
AU (1) AU654846B2 (en)
BR (1) BR9201043A (en)
DE (1) DE4209472A1 (en)
ES (1) ES2073804T3 (en)
HU (1) HUT62376A (en)
RU (1) RU2066405C1 (en)
TR (1) TR27218A (en)

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US5644915A (en) * 1996-04-25 1997-07-08 Cincinnati, Incorporated Control system for a hydraulic press brake
DE19647994A1 (en) * 1996-11-20 1998-05-28 Rexroth Mannesmann Gmbh Load-sensitive hydraulic control for e.g. waste disposal vehicles
DE19715020A1 (en) * 1997-04-11 1998-10-15 Rexroth Mannesmann Gmbh Hydraulic control system for transporting vehicle, especially sedimentation vessels
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EP1754682B1 (en) * 2005-08-11 2007-07-04 HAWE Hydraulik GmbH &amp; Co. KG Electrohydraulic device
US8727740B2 (en) * 2007-01-05 2014-05-20 Schlumberger Technology Corporation Cylinder assembly for providing uniform flow output
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KR101180224B1 (en) 2010-07-07 2012-09-05 주식회사 포스코 Appartus for supporting molten metal container
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Also Published As

Publication number Publication date
HU9200956D0 (en) 1992-06-29
EP0505977B1 (en) 1995-05-24
AU1315792A (en) 1992-10-01
HUT62376A (en) 1993-04-28
ES2073804T3 (en) 1995-08-16
AU654846B2 (en) 1994-11-24
RU2066405C1 (en) 1996-09-10
TR27218A (en) 1994-11-20
US5325761A (en) 1994-07-05
JPH0571504A (en) 1993-03-23
KR920019060A (en) 1992-10-22
DE4209472A1 (en) 1992-10-08
BR9201043A (en) 1992-11-24

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