EP1371859A1 - Electrohydraulic clamping device - Google Patents

Electrohydraulic clamping device Download PDF

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Publication number
EP1371859A1
EP1371859A1 EP03006777A EP03006777A EP1371859A1 EP 1371859 A1 EP1371859 A1 EP 1371859A1 EP 03006777 A EP03006777 A EP 03006777A EP 03006777 A EP03006777 A EP 03006777A EP 1371859 A1 EP1371859 A1 EP 1371859A1
Authority
EP
European Patent Office
Prior art keywords
pressure
valve
control
clamping
proportional
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
EP03006777A
Other languages
German (de)
French (fr)
Other versions
EP1371859B1 (en
Inventor
Georg Dipl.-Ing. Neumair (Fh)
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hawe Hydraulik GmbH and Co KG
Original Assignee
Hawe Hydraulik GmbH and Co KG
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Publication date
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Publication of EP1371859A1 publication Critical patent/EP1371859A1/en
Application granted granted Critical
Publication of EP1371859B1 publication Critical patent/EP1371859B1/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • 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
    • F15B11/028—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the actuating force
    • 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
    • F15B20/00—Safety arrangements for fluid actuator systems; Applications of safety devices in fluid actuator systems; Emergency measures for fluid actuator systems
    • F15B20/002—Electrical failure
    • 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
    • F15B2211/20538—Type of pump constant capacity
    • 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
    • F15B2211/3105—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
    • F15B2211/50—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
    • F15B2211/50536—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using unloading valves controlling the supply pressure by diverting fluid to 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
    • F15B2211/50—Pressure control
    • F15B2211/52—Pressure control characterised by the type of actuation
    • F15B2211/528—Pressure 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
    • F15B2211/50—Pressure control
    • F15B2211/57—Control of a differential 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
    • F15B2211/605—Load sensing circuits
    • F15B2211/6051—Load sensing circuits having valve means between output member and the load sensing circuit
    • 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
    • F15B2211/635—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

Definitions

  • EP 0 884 486 A DE 201 14 538 U.
  • the invention has for its object an electro-hydraulic clamping device of the type mentioned at the beginning with an increased safety standard, regardless of whether the clamping pressure is electrical or manual is set.
  • the proportional magnet the proportional pressure control valve is only energized again in this control routine, if a change in the clamping pressure (wanted or for readjustment) is required becomes.
  • the safety valve shut off in both directions without leakage is also useful for electrohydraulic clamping devices where the clamping pressure is set manually.
  • the safety valve is expediently a seat valve which is structurally simple and inexpensive and is reliable, and both flow directions are leak-free in the shut-off position blocked. Because the spring load of the closing element for the shut-off position is responsible, a simple black / white switching magnet can be used for the safety valve be used.
  • a compact design with as few components as possible is an important aspect such electro-hydraulic clamping devices.
  • the magnets of the safety valve are also and the proportional pressure control valve combined into a double magnet that common connector.
  • electrohydraulic tensioning device is a superordinate, electronic control and / or To provide monitoring device, preferably an electrical Has adjusting device for the clamping pressure.
  • an analog pressure sensor is expediently provided for tapping the actual clamping pressure, which, preferably, to a tension pressure signal line separate from the main circuit connected.
  • the analog pressure transducer provides in a control loop in which at least the proportional solenoid of the proportional pressure control valve and the switching magnet of the safety valve are included, the actual value of the clamping pressure ready, whereby an automatic control with target and actual value comparison is possible, or at least an alarm can be given if the clamping pressure monitored by the analog pressure sensor may be too low or too high should.
  • the analog pressure sensor continuously provides the necessary information for the control device is available, as opposed to usually only one visual and passive display offering manometer.
  • the analog pressure transducer with a display and / or alarm device is useful and / or the higher-level control and / or monitoring device connected.
  • the control routine after setting the Target pressure the proportional solenoid of the proportional pressure control valve completely to de-energize and leave the safety valve in the shut-off position increased Operational security given.
  • An electrohydraulic tensioning device S according to FIG. 1 is used for adjustment (e.g. Loosening and tightening) of a clamping element 1 and contains one as the main component Hydraulic control 2, which, preferably, a higher-level electronic control and / or Monitoring device 3 is assigned.
  • a signal device 4 can indicate a good or fault condition.
  • An adjusting device 5 is used, for example for electrical adjustment of the clamping pressure.
  • the hydraulic control 2 is in a main circuit 6 (pressure line) by a pump P) supplied.
  • a pressure compensator upstream of a clamping pressure valve V.
  • DW arranged. From a directional control valve W downstream of the clamping pressure valve V lead work lines 27, 26 to the clamping element or the clamping group 1.
  • a Return line 13 leads to a pressure medium reservoir. Downstream of the clamping pressure valve V branches from the main circuit 6, a line 21, for example to a manometer Mab.
  • the pressure compensator DW is determined by the pressure in line 21 and the force of a spring 22 in the closing direction and the main circuit pressure between the pressure compensator DW and the clamping pressure valve V in the opening direction.
  • An electrical switch 8 is assigned to the clamping pressure valve V, for example emits a good signal when the target clamping pressure is reached and to the control device 3 transmitted.
  • the clamping pressure valve V contains one loaded by a control spring 11 Control piston K for adjusting the size of an orifice 7.
  • the clamping pressure determining control spring 10 is arranged by a in a control chamber 9 Adjusting piston 10 acted upon.
  • the safety valve D is countered by a black / white switching magnet 14 the force of a spring 16 from the shut-off position O shown in a through position c adjusted.
  • a shut-off device C is included in the shut-off position 0 there is no leakage in both flow directions, i.e. any Flow from the control chamber 9 to the proportional pressure control valve B and conversely prevented.
  • An analog pressure sensor A is connected to the clamping pressure signal line 12, the (indicated by dashed lines), as well as the other electrically operated components the hydraulic control 2, be connected to the control device 3 can.
  • the analog pressure sensor A reports the actual clamping pressure, which when switched Directional control valve W prevails in one of the working lines 27, 26.
  • the electrical switch 8 gives a signal at a predetermined position of the control piston K, which is matched to the target clamping pressure.
  • the DW pressure compensator holds regardless of pressure fluctuations on the part of the clamping pressure valve V or Pump P the pressure difference at the control piston K constant, so that the electrical Switch 8 signal is strictly quantity-dependent and clear.
  • the clamping element 1 is in its release position. By applying the Working line 27 it is brought into its clamping position in which it has a workpiece should maintain a target clamping pressure.
  • the target clamping pressure is, for example, at Adjustment device 5 set.
  • the safety valve D is activated of the switching magnet 14 from the shut-off position shown in its through position c adjusted.
  • the proportional magnet 15 of the proportional pressure control valve B from the control device 3 with a precisely determined one Current energized with the target clamping pressure or a target pressure in the control chamber 9 corresponds. Pressure is present in the setting pilot circuit, from which the Proportional pressure control valve B in the control chamber 9 the predetermined target pressure established.
  • the directional control valve W is in his Switch position brought in which the main circuit 6 connected to the working line 27 is while the working line 26 is connected to the return line 13. through of the clamping pressure signal in line 12, the control piston K controls the soli clamping pressure exactly a, the reaching of which, for example, by triggering the switch 8 is reported.
  • the switching magnet 14 is de-energized, so that the safety valve D in its shut-off position shown goes before the proportional magnet 15 is de-energized and the setting pilot circuit between the safety valve D and the proportional pressure control valve B to the return line 13 is relieved.
  • Pressure fluctuations in Main circuit 6 caused by the pressure relief valve V, the pump P or leakage in the Clamping element 1 are caused, the pressure compensator DW compensates, so that the Pressure difference at the control piston K is kept constant.
  • the directional control valve W is changed over so that the working line 27 with the return line 13 and the working line 26 with the Main circuit 6 is connected.
  • the controller 2 is explained in detail with reference to FIGS. 2 and 3, with FIG. 3 being a Section in the section plane III-III in Fig. 2 is. It should be emphasized that the pressure compensator DW and / or the analog pressure transducer A is not absolutely necessary, but are convenient options.
  • the linearly displaceable control piston K of the clamping pressure valve V in the middle block is relieved on its side loaded by the adjusting spring 11 to the return line 13, and receives the tension pressure signal on line 12 on the opposite side. It positions itself in a position in which it works through the cooperation of its control edge with a housing edge adjusts the amount for the target clamping pressure via an orifice 7.
  • the control piston operates with the end acted upon by the clamping pressure signal K the electrical switch 8, whose switching point to the position of the control piston K is set, which is the target clamping pressure, or because of a constant pressure difference via the control piston K maintaining pressure compensator DW, a certain one Quantity (flow rate) of the pressure medium through the orifice corresponds.
  • the switching point of the electrical switch 8 is, for example, by inserting or removing of documents 18 precisely adjusted to the aforementioned position of the control piston K.
  • the directional control valve W connects one of the depending on the current supply Magnets 25, 24 the main circuit 6 with one or the other working line 26, 27.
  • the actual clamping pressure prevailing in the respective working line 26 or 27 becomes tapped permanently by the analog pressure transducer A.
  • the middle block is the preload of the actuating spring 11 by the actuating piston 10 by means of the pressure prevailing in the control chamber 9.
  • the safety valve D and the proportional pressure control valve B are expediently side by side in a head part 19 of the control chamber 9 placed.
  • the proportional magnet 15 is included the switching magnet 14 combined to form a double magnet on Headboard 19 is mounted and a common plug connection for both functions Owns 20. This is symbolized by the inscription SW and PROP in Fig. 3.
  • the two magnets can also be designed and assembled separately.
  • the Valves B and D can be installed separately, if necessary with their own blocks.
  • the proportional pressure control valve B is expediently a screw-in valve, which in the Head part 19 in a chamber between a connection bore 28 of the setting precontrol circuit and a channel 29 to another receiving the safety valve D. Chamber sits in the head part 19.
  • the safety valve D is a seat valve (screw-in valve), a closing element 31 with a spherical or conical sealing surface and has a matching valve seat 30.
  • the valve seat 30 is hollow Shaped housing insert, in which the switching magnet 14, the closing element 31st against the force of the spring 17 and the pressure in the channel 29 from the shut-off position shown can lift off the valve seat 30 and bring it into the open position.
  • the Closing element 31 is acted upon by the pressure in channel 29 in the closing direction.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

The clamp (1) is operated through a valve (W), pump (P) and pressure control valve (V) set by a pressure control chamber (9) set by a proportional pressure valve (B) and electromagnetic safety valve (D) according to a sensor (A) connected to the control system (3).

Description

Die Erfindung betrifft eine elektrohydraulische Spannvorrichtung der im Oberbegriff des Anspruchs 1 angegebenen Art.The invention relates to an electro-hydraulic clamping device in the preamble of claim 1 specified Art.

An solche aus DE 44 23 585 A bekannte, elektrohydraulische Spannvorrichtungen werden von den Anwendem bzw. Werkzeugmaschinen-Herstellem außerordentlich hohe sicherheitstechnische Anforderungen gestellt. Einerseits sind an Werkzeugmaschinen auftretende Schäden sehr teuer und zeitaufwendig zu beheben, auch wegen häufig immenser Kosten von Ausfall- oder Reparaturzeiten. Andererseits sind Schäden an den Werkstücken, verursacht durch eine Fehlfunktion der Werkzeugmaschine, unbedingt zu vermeiden. Beispielsweise kann sich im elektrischen System der Werkzeugmaschine der Strom bzw. die Spannung ungewollt verändern, wodurch der Proportionalmagnet des Proportional-Druckregelventils über das in seiner Absperrstellung in Strömungsrichtung zur Steuerkammer durchgängige Sicherungsventil den an sich fest eingestellten Druck in der Steuerkammer verändert, was eine ungewollte Veränderung des Spanndrucks über das Spanndruckventil hervorruft. Diese Veränderung wird in der Steuervorrichtung nicht wahrgenommen, weil von korrekten Stromverhältnissen ausgegangen wird und der elektrische Schalter des Spanndruckventils ggfs. nach wie vor "Spanndruck vorhanden" meldet. Ferner kann in der Absperrstellung des Sicherungsventils und bestromten Proportionalmagneten des Druckregelventils die Pumpe ungewollt durchschlagen und den Druck in der Steuerkammer ungewollt steigem. Ein zu hoher bzw. zu niedriger Spanndruck kann dann einen Schaden an den Werkstücken und/oder Komponenten der Werkzeugmaschine hervorrufen.To those known from DE 44 23 585 A, electro-hydraulic clamping devices become extraordinary by the users or machine tool manufacturers high security requirements. On the one hand are on machine tools Damage that occurs is very expensive and time-consuming to fix, also because of often immense costs of downtime or repair times. On the other hand there are damages on the workpieces caused by a malfunction of the machine tool, to be avoided at all costs. For example, in the electrical system of the machine tool the current or the voltage change unintentionally, causing the proportional magnet of the proportional pressure control valve via that in its shut-off position in the direction of flow to the control chamber continuous safety valve itself Fixed pressure in the control chamber changes, which is an unwanted change of the clamping pressure via the clamping pressure valve. This change is not perceived in the control device because of correct current conditions is assumed and the electrical switch of the clamping pressure valve if necessary. still reports "clamping pressure present". Furthermore, in the shut-off position Safety valve and energized proportional solenoids of the pressure control valve Pump through unintentionally and increase the pressure in the control chamber unintentionally. A too high or too low clamping pressure can then damage the Cause workpieces and / or components of the machine tool.

Von Interesse sind femer: EP 0 884 486 A, DE 201 14 538 U.Also of interest are: EP 0 884 486 A, DE 201 14 538 U.

Der Erfindung liegt die Aufgabe zugrunde, eine elektrohydraulische Spannvorrichtung der eingangs genannten Art mit erhöhtem sicherheitstechnischem Standard anzugeben, und zwar unabhängig davon, ob der Spanndruck elektrisch oder manuell eingestellt wird.The invention has for its object an electro-hydraulic clamping device of the type mentioned at the beginning with an increased safety standard, regardless of whether the clamping pressure is electrical or manual is set.

Die gestellte Aufgabe wird mit den Merkmalen des Anspruchs 1 gelöst. The object is achieved with the features of claim 1.

Da das Sicherungsventil in seiner Absperrstellung in beiden Strömungsrichtungen leckagefrei dicht ist, kann eine Druckanhebung oder Druckabsenkung durch das sich ungewollt verstellende Proportional-Druckregelventil oder beim Durchschlagen der Pumpe keine Veränderung der Einstellung am Spanndruckventil bewirken. Dank der leckagefreien Abdichtung im Sicherungsventil in jeder Strömungsrichtung kann bei elektrischer Einstellbarkeit des Spanndruckes sogar eine Steuerroutine eingesetzt werden, bei der nach Einstellung des Spanndruckes über das Proportional-Druckregelventil bei in seine Durchgangsstellung geschaltetem Sicherungsventil zunächst das Sicherungsventil in die Absperrstellung gebracht und dann der Proportionalmagnet des Proportional-Druckregelventils vollständig entregt wird. Dadurch können sich weder Stromänderungen auf das Proportional-Druckregelventil noch ein Durchschlagen der Pumpe in der Steuerkammer auswirken. Der Proportionalmagnet des Proportional-Druckregelventils wird bei dieser Steuerroutine erst wieder bestromt, wenn eine Änderung des Spanndruckes (gewollt oder zwecks Nachregelung) erforderlich wird. Das in beiden Strömungsrichtungen leckagefrei absperrende Sicherungsventil ist auch für elektrohydraulische Spannvorrichtungen zweckmäßig, bei denen der Spanndruck manuell eingestellt wird.Since the safety valve in its shut-off position is leak-free in both flow directions is tight, a pressure increase or pressure decrease by itself unintentionally adjusting proportional pressure control valve or when striking the Do not cause the pump to change the setting on the clamping pressure valve. thanks to the Leak-free sealing in the safety valve in any flow direction can be electrical Adjustability of the clamping pressure even a control routine can be used after setting the clamping pressure via the proportional pressure control valve with the safety valve switched into its through position initially put the safety valve in the shut-off position and then the proportional solenoid of the proportional pressure control valve is completely de-energized. This allows neither changes in current to the proportional pressure control valve Impact the pump in the control chamber. The proportional magnet the proportional pressure control valve is only energized again in this control routine, if a change in the clamping pressure (wanted or for readjustment) is required becomes. The safety valve shut off in both directions without leakage is also useful for electrohydraulic clamping devices where the clamping pressure is set manually.

Zweckmäßig ist das Sicherungsventil ein Sitzventil, das baulich einfach, kostengünstig und funktionssicher ist, und in der Absperrstellung beide Strömungsrichtungen leckagefrei blockiert. Da die Federbelastung des Schließelements für die Absperrstellung verantwortlich ist, kann ein einfacher Schwarz/Weiß-Schaltmagnet für das Sicherungsventil verwendet werden.The safety valve is expediently a seat valve which is structurally simple and inexpensive and is reliable, and both flow directions are leak-free in the shut-off position blocked. Because the spring load of the closing element for the shut-off position is responsible, a simple black / white switching magnet can be used for the safety valve be used.

Eine kompakte Bauweise mit möglichst wenigen Komponenten ist ein wichtiger Aspekt solcher elektrohydraulischer Spannvorrichtungen. Durch nebeneinanderliegendes Anordnen des Sicherungsventils und des Proportional-Druckregelventils in einem Kopfteil der Steuerkammer wird Bauraum gespart und werden weniger Einzelteile benötigt. A compact design with as few components as possible is an important aspect such electro-hydraulic clamping devices. By side by side Placing the safety valve and the proportional pressure control valve in one The head part of the control chamber saves installation space and fewer individual parts are required.

Im Sinne einer kompakte Bauweise werden auch die Magneten des Sicherungsventils und des Proportional-Druckregelventils zu einem Doppelmagneten kombiniert, der gemeinsame Anschlussstecker aufweist.In the sense of a compact design, the magnets of the safety valve are also and the proportional pressure control valve combined into a double magnet that common connector.

Da moderne Werkzeugmaschinen computerisiert sind, ist es zweckmäßig, auch für die elektrohydraulische Spannvorrichtung eine übergeordnete, elektronische Steuerund/Oder Überwachungsvorrichtung vorzusehen, die vorzugsweise, eine elektrische Einstellvorrichtung für den Spanndruck aufweist.Since modern machine tools are computerized, it is also useful for the electrohydraulic tensioning device is a superordinate, electronic control and / or To provide monitoring device, preferably an electrical Has adjusting device for the clamping pressure.

Um eine saubere automatische Spanndruck-Regelung anwenden zu können, wird zweckmäßig ein Analog-Druckaufnehmer zum Abgreifen des Ist-Spanndrucks vorgesehen, der, vorzugsweise, an eine vom Hauptkreis getrennte Spanndruck-Signalleitung angeschlossen ist. Der Analog-Druckaufnehmer stellt in einem Regelkreis, in welchem zumindest der Proportionalmagnet des Proportional-Druckregelventils und der Schaltmagnet des Sicherungsventils enthalten sind, den Ist-Wert des Spanndrucks bereit, wodurch eine automatische Regelung mit Soll- und Ist-Wertabgleichung möglich ist, oder zumindest Alarm gegeben werden kann, falls der vom Analog-Druckaufnehmer überwachte Spanndruck zu niedrig oder zu hoch sein sollte. Der Analog-Druckaufnehmer stellt fortlaufend die notwendige Information für die Steuervorrichtung zur Verfügung, im Gegensatz zu einem üblicherweise nur eine visuelle und passive Anzeige bietenden Manometer.In order to be able to use a clean automatic clamping pressure control, an analog pressure sensor is expediently provided for tapping the actual clamping pressure, which, preferably, to a tension pressure signal line separate from the main circuit connected. The analog pressure transducer provides in a control loop in which at least the proportional solenoid of the proportional pressure control valve and the switching magnet of the safety valve are included, the actual value of the clamping pressure ready, whereby an automatic control with target and actual value comparison is possible, or at least an alarm can be given if the clamping pressure monitored by the analog pressure sensor may be too low or too high should. The analog pressure sensor continuously provides the necessary information for the control device is available, as opposed to usually only one visual and passive display offering manometer.

Zweckmäßig wird der Analog-Druckaufnehmer mit einer Anzeige- und/oder Alarmeinrichtung und/oder der übergeordneten Steuer- und/oder Überwachungsvorrichtung verbunden. Auf diese Weise ist mit der Steuerroutine, nach erfolgter Einstellung des Sollspanndrucks den Proportionalmagneten des Proportional-Druckregelventils vollständig zu entregen und das Sicherungsventil in der Absperrstellung zu belassen, erhöhte Betriebssicherheit gegeben.The analog pressure transducer with a display and / or alarm device is useful and / or the higher-level control and / or monitoring device connected. In this way, with the control routine, after setting the Target pressure the proportional solenoid of the proportional pressure control valve completely to de-energize and leave the safety valve in the shut-off position increased Operational security given.

Ein vom Regelkolben betätigter, elektrischer Schalter meldet das Erreichen oder Fehlen des Spanndrucks, z.B. an die Steuervorrichtung. Da jedoch der Regelkolben kleinere Druckänderungen im System (z.B. hervorgerufen durch druckabhängig variierende Leckageverluste im Spannelement, oder beim Speicher-Ladebetrieb) nicht einwandfrei beherrschen kann (z.B. aufgrund eines relativ hohen Losbrechwiderstandes des Regelkolbens), und dann das Signal des Schalters keine zuverlässige Aussage liefern kann, ist es zweckmäßig, dem Regelkolben eine Druckwaage zuzuordnen. Die Druckwaage kompensiert auch kleinere Druckschwankungen zuverlässig und hält die Druckdifferenz am Regelkolben konstant. Der Regelkolben ist von dieser Aufgabe entlastet. Als positivere Nebeneffekt zur Steigerung der Betriebssicherheit korrespondiert dann dank der Druckwaage die Schaltpunktposition des Regelkolbens nur mehr mit der über den Regelkolben strömenden Menge, so dass das Signal des Schalters eine eindeutige und zuverlässige Aussage liefert, unter anderem, weil der Schaltpunkt sehr genau eingestellt werden kann. Dies ist besonders günstig, wenn eine automatische Spanndruckregelung vorgenommen wird, oder wenn der Spanndruck während der Bearbeitung eines Werkstücks geändert wird, und zwar unabhängig davon ob der Spanndruck manuell oder elektrisch eingestellt wird.An electrical switch actuated by the control piston reports that it has reached or Lack of clamping pressure, e.g. to the control device. However, since the control piston minor pressure changes in the system (e.g. caused by pressure-dependent variations Leakage losses in the tensioning element, or during store loading operation) are not perfect can control (e.g. due to a relatively high breakaway resistance of the control piston), and then the signal from the switch is not a reliable statement can deliver, it is appropriate to assign a pressure compensator to the control piston. The Pressure compensator also reliably compensates for and keeps small pressure fluctuations Pressure difference at the control piston is constant. The control piston is of this task relieved. Corresponds as a more positive side effect to increasing operational safety then, thanks to the pressure compensator, the switching point position of the control piston only becomes more with the amount flowing over the control piston, so that the signal of the switch provides a clear and reliable statement, among other things because of the switching point can be set very precisely. This is particularly convenient if automatic Tension pressure control is made, or if the tension pressure during the machining of a workpiece is changed, regardless of whether the Clamping pressure is set manually or electrically.

Das erfindungsgemäß Konzept ist sicherheitstechnisch sauber und wehrt ungewollte elektrische und/oder hydraulische Einflüsse selbsttätig ab, die zu Schäden in der Werkzeugmaschine und/oder an Werkstücken führen könnten.The concept according to the invention is clean in terms of security and prevents unwanted ones electrical and / or hydraulic influences automatically, leading to damage in the Machine tool and / or lead to workpieces.

Anhand der Zeichnung wird eine Ausführungsform des Erfindungsgegenstandes erläutert. Es zeigen:

Fig. 1
ein symbolisiertes Blockschaltbild einer elektrohydraulischen Spannvorrichtung für eine Werkzeugmaschine,
Fig. 2
einen Teilschnitt einer konkreten Ausführungsform der elektrohydraulischen Steuerung der Spannvorrichtung, und
Fig. 3
einen Schnitt in der Schnittebene III-III in Fig. 2.
An embodiment of the subject matter of the invention is explained with the aid of the drawing. Show it:
Fig. 1
a symbolized block diagram of an electrohydraulic clamping device for a machine tool,
Fig. 2
a partial section of a specific embodiment of the electro-hydraulic control of the clamping device, and
Fig. 3
a section in the section plane III-III in Fig. 2nd

Eine elektrohydraulische Spannvorrichtung S gemäß Fig. 1 dient zum Verstellen (z.B. Lösen und Anziehen) eines Spannelements 1 und enthält als Hauptkomponente eine Hydrauliksteuerung 2, der, vorzugsweise, eine übergeordnete elektronische Steuerund/Oder Überwachungseinrichtung 3 zugeordnet ist. Eine Signaleinrichtung 4 kann eine Gut- oder Fehlerzustand anzeigen. Eine Einstellvorrichtung 5 dient beispielsweise zum elektrischen Einstellen des Spanndrucks.An electrohydraulic tensioning device S according to FIG. 1 is used for adjustment (e.g. Loosening and tightening) of a clamping element 1 and contains one as the main component Hydraulic control 2, which, preferably, a higher-level electronic control and / or Monitoring device 3 is assigned. A signal device 4 can indicate a good or fault condition. An adjusting device 5 is used, for example for electrical adjustment of the clamping pressure.

Die Hydrauliksteuerung 2 wird in einem Hauptkreis 6 (Druckleitung) von einer Pumpe P) versorgt. Im Hauptkreis 6 ist stromauf eines Spanndruckventils V eine Druckwaage DW angeordnet. Von einem Wegesteuerventil W stromab des Spanndruck-Ventils V führen Arbeitsleitungen 27, 26 zum Spannelement bzw. der Spanngruppe 1. Eine Rücklaufleitung 13 führt zu einem Druckmittelreservoir. Stromab des Spanndruckventils V zweigt vom Hauptkreis 6 eine Leitung 21 beispielsweise zu einem Manometer Mab. Die Druckwaage DW wird vom Druck in der Leitung 21 und der Kraft einer Feder 22 in Schließrichtung und vom Hauptkreis-Druck zwischen der Druckwaage DW und dem Spanndruckventil V in Öffnungsrichtung beaufschlagt.The hydraulic control 2 is in a main circuit 6 (pressure line) by a pump P) supplied. In the main circuit 6 there is a pressure compensator upstream of a clamping pressure valve V. DW arranged. From a directional control valve W downstream of the clamping pressure valve V lead work lines 27, 26 to the clamping element or the clamping group 1. A Return line 13 leads to a pressure medium reservoir. Downstream of the clamping pressure valve V branches from the main circuit 6, a line 21, for example to a manometer Mab. The pressure compensator DW is determined by the pressure in line 21 and the force of a spring 22 in the closing direction and the main circuit pressure between the pressure compensator DW and the clamping pressure valve V in the opening direction.

Dem Spanndruckventil V ist ein elektrischer Schalter 8 zugeordnet, der beispielsweise bei Erreichen des Sollspanndrucks ein Gutsignal abgibt und an die Steuervorrichtung 3 übermittelt. Das Spanndruckventil V enthält einen durch eine Regelfeder 11 belasteten Regelkolben K zum Einstellen der Größe einer Blende 7. Die den Spanndruck bestimmende Regelfeder 10 wird durch einen in einer Steuerkammer 9 angeordneten Einstellkolben 10 beaufschlagt.An electrical switch 8 is assigned to the clamping pressure valve V, for example emits a good signal when the target clamping pressure is reached and to the control device 3 transmitted. The clamping pressure valve V contains one loaded by a control spring 11 Control piston K for adjusting the size of an orifice 7. The clamping pressure determining control spring 10 is arranged by a in a control chamber 9 Adjusting piston 10 acted upon.

Im Wegesteuerventil W, das durch Magneten 25, 24 aus der gezeigten Neutralstellung in zwei Steuerstellungen verstellbar ist, zweigt eine Spanndrucksignalleitung 12 ab, deren Signaldruck auf den Regelkolben K im Spanndruckventil V entgegengesetzt zur Kraft der Regelfeder 11 zurückgeführt wird. Ein Einstell-Vorsteuerkreis zweigt vom Hauptkreis 6 zwischen der Druckwaage DW und dem Spanndruckventil V ab und führt über ein Proportional-Druckregelventil B und ein diesem nachgeordnetes Sicherungsventil D zur Steuerkammer 9. Das Proportional-Druckregelventil B wird gegen die Kraft einer Regelfeder 16 durch einen Proportionalmagneten 15 verstellt, beispielsweise von der Steuervorrichtung 3.In the directional control valve W by magnets 25, 24 from the neutral position shown is adjustable in two control positions, a clamping pressure signal line 12 branches from, the signal pressure on the control piston K in the clamping pressure valve V opposite is returned to the force of the control spring 11. A setting pilot circuit branches from Main circuit 6 between the pressure compensator DW and the clamping pressure valve V and leads via a proportional pressure control valve B and a downstream safety valve D to the control chamber 9. The proportional pressure control valve B is against the Force of a control spring 16 adjusted by a proportional magnet 15, for example from the control device 3.

Das Sicherungsventil D wird durch einen Schwarz/Weiß-Schaltmagneten 14 gegen die Kraft einer Feder 16 aus der gezeigten Absperrstellung O in eine Durchgangsstellung c verstellt. Im Sicherungsventil 14 ist eine Absperrvorrichtung C enthalten, die in der Absperrstellung 0 in beiden Strömungsrichtungen leckagefrei dicht ist, d.h., jegliche Strömung aus der Steuerkammer 9 zum Proportional-Druckregelventil B und umgekehrt verhindert.The safety valve D is countered by a black / white switching magnet 14 the force of a spring 16 from the shut-off position O shown in a through position c adjusted. In the safety valve 14, a shut-off device C is included in the shut-off position 0 there is no leakage in both flow directions, i.e. any Flow from the control chamber 9 to the proportional pressure control valve B and conversely prevented.

An die Spanndrucksignalleitung 12 ist ein Analog-Druckaufnehmer A angeschlossen, der (gestrichelt angedeutet), wie auch die anderen, elektrisch zu betätigenden Komponenten der Hydrauliksteuerung 2, an die Steuervorrichtung 3 angeschlossen sein kann. Der Analog-Druckaufnehmer A meldet den Ist-Spanndruck, der bei geschaltetem Wegesteuerventil W in einer der Arbeitsleitungen 27, 26 herrscht.An analog pressure sensor A is connected to the clamping pressure signal line 12, the (indicated by dashed lines), as well as the other electrically operated components the hydraulic control 2, be connected to the control device 3 can. The analog pressure sensor A reports the actual clamping pressure, which when switched Directional control valve W prevails in one of the working lines 27, 26.

Der elektrische Schalter 8 gibt ein Signal bei einer vorbestimmten Position des Regelkolbens K ab, die auf den Soll-Spanndruck abgestimmt ist. Die Druckwaage DW hält unabhängig von Druckschwankungen seitens des Spanndruckventils V bzw. der Pumpe P die Druckdifferenz am Regelkolben K konstant, so dass das vom elektrischen Schalter 8 abgegebenen Signal strikt mengenabhängig und eindeutig ist.The electrical switch 8 gives a signal at a predetermined position of the control piston K, which is matched to the target clamping pressure. The DW pressure compensator holds regardless of pressure fluctuations on the part of the clamping pressure valve V or Pump P the pressure difference at the control piston K constant, so that the electrical Switch 8 signal is strictly quantity-dependent and clear.

Operation:Surgery:

Das Spannelement 1 befindet sich in seiner Lösestellung. Durch Beaufschlagen der Arbeitsleitung 27 wird es in seine Spannstellung gebracht, in der es ein Werkstück mit einem Soll-Spanndruck halten soll. Der Soll-Spanndruck ist beispielsweise an der Einstellvorrichtung 5 eingestellt. Das Sicherungsventil D wird durch Beaufschlagen des Schaltmagneten 14 aus der gezeigten Absperrstellung in seine Durchgangsstellung c verstellt. In Etwa zur gleichen Zeit wird der Proportionalmagnet 15 des Proportional-Druckregelventils B von der Steuervorrichtung 3 mit einem exakt bestimmten Strom bestromt, der mit dem Soll-Spanndruck bzw. einem Soll-Druck in der Steuerkammer 9 korrespondiert. Im Einstell-Vorsteuerkreis steht Druck an, aus dem das Proportional-Druckregelventil B in der Steuerkammer 9 den vorbestimmten Soll-Druck einstellt. In etwa gleichzeitig oder nacheilend wird das Wegesteuerventil W in seine Schaltstellung gebracht, in der der Hauptkreis 6 mit der Arbeitsleitung 27 verbunden ist, während die Arbeitsleitung 26 mit der Rücklaufleitung 13 verbunden wird. Mittels des Spanndrucksignals in der Leitung 12 regelt der Regelkolben K exakt den Soli-Spanndruck ein, dessen Erreichen beispielsweise durch Ansprechen des Schalters 8 gemeldet wird. Der Schaltmagnet 14 wird entregt, so dass das Sicherungsventil D in seine gezeigte Absperrstellung geht, ehe der Proportionalmagnet 15 entregt wird und der Einstellvorsteuerkreis zwischen dem Sicherungsventil D und dem Proportional-Druckregelventil B zur Rücklaufleitung 13 entlastet wird. Druckschwankungen im Hauptkreis 6, die durch das Spanndruckventil V, die Pumpe P oder von Leckagen im Spannelement 1 hervorgerufen werden, gleicht die Druckwaage DW aus, so dass die Druckdifferenz am Regelkolben K konstant gehalten wird.The clamping element 1 is in its release position. By applying the Working line 27 it is brought into its clamping position in which it has a workpiece should maintain a target clamping pressure. The target clamping pressure is, for example, at Adjustment device 5 set. The safety valve D is activated of the switching magnet 14 from the shut-off position shown in its through position c adjusted. At about the same time, the proportional magnet 15 of the proportional pressure control valve B from the control device 3 with a precisely determined one Current energized with the target clamping pressure or a target pressure in the control chamber 9 corresponds. Pressure is present in the setting pilot circuit, from which the Proportional pressure control valve B in the control chamber 9 the predetermined target pressure established. At about the same time or lagging, the directional control valve W is in his Switch position brought in which the main circuit 6 connected to the working line 27 is while the working line 26 is connected to the return line 13. through of the clamping pressure signal in line 12, the control piston K controls the soli clamping pressure exactly a, the reaching of which, for example, by triggering the switch 8 is reported. The switching magnet 14 is de-energized, so that the safety valve D in its shut-off position shown goes before the proportional magnet 15 is de-energized and the setting pilot circuit between the safety valve D and the proportional pressure control valve B to the return line 13 is relieved. Pressure fluctuations in Main circuit 6 caused by the pressure relief valve V, the pump P or leakage in the Clamping element 1 are caused, the pressure compensator DW compensates, so that the Pressure difference at the control piston K is kept constant.

Der Analogdruckaufnehmer A meldet permanent den Ist-Spanndruck an die Steuervorrichtung 3. Diese veranlasst ein Alarmsignal, falls sich der Spanndruck ungewollt erhöhen oder verringern sollte, oder bewirkt eine Nachregelung des Spanndrucks auf den Solldruck-Spanndruck durch erneutes Ansteuern der Magneten 14,15. Bei dieser Regelung dient das Signal des Analogdruckaufnehmers als Ist-Wert einer geschlossenen Regelschleife.The analog pressure sensor A continuously reports the actual clamping pressure to the control device 3. This triggers an alarm signal if the clamping pressure is unwanted should increase or decrease, or causes a readjustment of the clamping pressure the target pressure clamping pressure by triggering the magnets 14, 15 again. At this The signal from the analog pressure transducer serves as the actual value of a closed control Control loop.

Zum Lösen des Spannelementes 1 wird das Wegesteuerventil W umgestellt, so dass die Arbeitsleitung 27 mit der Rücklaufleitung 13 und die Arbeitsleitung 26 mit dem Hauptkreis 6 verbunden wird.To release the tensioning element 1, the directional control valve W is changed over so that the working line 27 with the return line 13 and the working line 26 with the Main circuit 6 is connected.

Die Steuerung 2 wird detailliert anhand der Fig. 2 und 3 erläutert, wobei Fig. 3 ein Schnitt in der Schnittebene III-III in Fig. 2 ist. Es ist hervorzuheben, dass die Druckwaage DW und/oder der Analog-Druckaufnehmer A nicht zwangsweise erforderlich, sondern zweckmäßige Optionen sind.The controller 2 is explained in detail with reference to FIGS. 2 and 3, with FIG. 3 being a Section in the section plane III-III in Fig. 2 is. It should be emphasized that the pressure compensator DW and / or the analog pressure transducer A is not absolutely necessary, but are convenient options.

Die Hydraulik-Steuerung 2 ist aus mehreren miteinander verbundenen Blöcken zusammengesetzt, wobei in Fig. 2 im unteren Block der Hauptkreis 6 zur Druckwaage DW führt. Die Regelfeder 22 der Druckwaage DW beaufschlagt einen Druckwaagenkolben 23, in Öffnungsrichtung parallel zu dem, wie erwähnt, hinter dem Druckwaagenkolben 23 eingespeisten Druck aus der hier nicht gezeigten Leitung 21, während gleichzeitig der Druckwaagenkolben 23 durch den Hauptkreisdruck stromauf des Spanndruckventils V in Schließrichtung belastet wird. The hydraulic control 2 is composed of several blocks connected to one another, 2 in the lower block of the main circuit 6 for the pressure compensator DW leads. The control spring 22 of the pressure compensator DW acts on a pressure compensator piston 23, in the opening direction parallel to that, as mentioned, behind the pressure compensator piston 23 fed pressure from the line 21, not shown here, while at the same time the pressure compensator piston 23 upstream of the main circuit pressure Clamping pressure valve V is loaded in the closing direction.

Der im mittleren Block linear verschiebbare Regelkolben K des Spanndruckventils V ist an seiner von der Einstellfeder 11 belasteten Seite zur Rücklaufleitung 13 entlastet, und erhält an der entgegengesetzten Seite das Spanndrucksignal in der Leitung 12. Er stellt sich in eine Position ein, in der er durch Zusammenarbeit seiner Steuerkante mit einer Gehäusekante die Menge für den Soll-Spanndruck über eine Blende 7 einstellt. Mit dem vom Spanndrucksignal beaufschlagten Ende betätigt der Regelkolben K den elektrischen Schalter 8, dessen Schaltpunkt auf die Position des Regelkolbens K eingestellt ist, die dem Soll-Spanndruck, bzw. wegen der eine konstante Druckdifferenz über den Regelkolben K aufrechthaltenden Druckwaage DW, einer bestimmten Menge (Strömungsrate) des Druckmittels durch die Blende entspricht. Der Schaltpunkt des elektrischen Schalters 8 wird beispielsweise durch Einfügen oder Entnehmen von Unterlagen 18 exakt auf die erwähnte Position des Regelkolbens K einjustiert. Das Wegesteuerventil W verbindet abhängig von der Bestromung eines der Magneten 25, 24 den Hauptkreis 6 mit der einen oder der anderen Arbeitsleitung 26, 27. Der in der jeweiligen Arbeitsleitung 26 oder 27 herrschende Ist-Spanndruck wird von dem Analog-Druckaufnehmer A permanent abgegriffen.The linearly displaceable control piston K of the clamping pressure valve V in the middle block is relieved on its side loaded by the adjusting spring 11 to the return line 13, and receives the tension pressure signal on line 12 on the opposite side. It positions itself in a position in which it works through the cooperation of its control edge with a housing edge adjusts the amount for the target clamping pressure via an orifice 7. The control piston operates with the end acted upon by the clamping pressure signal K the electrical switch 8, whose switching point to the position of the control piston K is set, which is the target clamping pressure, or because of a constant pressure difference via the control piston K maintaining pressure compensator DW, a certain one Quantity (flow rate) of the pressure medium through the orifice corresponds. The switching point of the electrical switch 8 is, for example, by inserting or removing of documents 18 precisely adjusted to the aforementioned position of the control piston K. The directional control valve W connects one of the depending on the current supply Magnets 25, 24 the main circuit 6 with one or the other working line 26, 27. The actual clamping pressure prevailing in the respective working line 26 or 27 becomes tapped permanently by the analog pressure transducer A.

Im mittleren Block ist die Vorspannung der Stellfeder 11 durch den Stellkolben 10 mittels des in der Steuerkammer 9 herrschenden Drucks eingestellt. Das Sicherungsventil D und das Proportional-Druckregelventil B sind zweckmäßig nebeneinander in einem Kopfteil 19 der Steuerkammer 9 platziert. Der Proportionalmagnet 15 ist mit dem Schaltmagneten 14 zu einem Doppelmagneten zusammengefasst, der am Kopfteil 19 montiert ist und für beide Funktionen einen gemeinsamen Steckanschluss 20 besitzt. Dies ist durch die Beschriftung SW und PROP in Fig. 3 symbolisiert. Die beiden Magneten können aber auch getrennt ausgebildet und montiert sein. Auch die Ventile B und D können getrennt, gegebenenfalls mit eigenen Blöcken, installiert sein.In the middle block is the preload of the actuating spring 11 by the actuating piston 10 by means of the pressure prevailing in the control chamber 9. The safety valve D and the proportional pressure control valve B are expediently side by side in a head part 19 of the control chamber 9 placed. The proportional magnet 15 is included the switching magnet 14 combined to form a double magnet on Headboard 19 is mounted and a common plug connection for both functions Owns 20. This is symbolized by the inscription SW and PROP in Fig. 3. The However, the two magnets can also be designed and assembled separately. Also the Valves B and D can be installed separately, if necessary with their own blocks.

Das Proportional-Druckregelventil B ist zweckmäßig ein Einschraubventil, das im Kopfteil 19 in einer Kammer zwischen einer Anschlussbohrung 28 des Einstellvorsteuerkreises und einem Kanal 29 zu einer anderen, das Sicherungsventil D aufnehmenden Kammer im Kopfteil 19 sitzt. Das Sicherungsventil D ist ein Sitzventil (Einschraubventil), das ein Schließelement 31 mit kugeliger oder kegeliger Dichtfläche und einen dazu passenden Ventilsitz 30 aufweist. Der Ventilsitz 30 ist an einem hohlen Gehäuseeinsatz geformt, in welchem der Schaltmagnet 14 das Schließelement 31 gegen die Kraft der Feder 17 und den Druck im Kanal 29 aus der gezeigten Absperrstellung vom Ventilsitz 30 abheben und in die Durchgangsstellung bringen kann. Das Schließelement 31 wird vom Druck im Kanal 29 in Schließrichtung beaufschlagt. Vom Gehäuseeinsatz des Sicherungsventils D führt ein Kanal in die Steuerkammer 9. Das Schließelement 31 bildet mit dem Ventilsitz 30 und der Schließfeder 17 die Absperrvorrichtung C des Sicherungsventils D, die dank der Sitzventilfunktion in der Absperrstellung in beiden Strömungsrichtungen leckagefrei dicht ist.The proportional pressure control valve B is expediently a screw-in valve, which in the Head part 19 in a chamber between a connection bore 28 of the setting precontrol circuit and a channel 29 to another receiving the safety valve D. Chamber sits in the head part 19. The safety valve D is a seat valve (screw-in valve), a closing element 31 with a spherical or conical sealing surface and has a matching valve seat 30. The valve seat 30 is hollow Shaped housing insert, in which the switching magnet 14, the closing element 31st against the force of the spring 17 and the pressure in the channel 29 from the shut-off position shown can lift off the valve seat 30 and bring it into the open position. The Closing element 31 is acted upon by the pressure in channel 29 in the closing direction. from Housing insert of the safety valve D leads a channel into the control chamber 9. Das Closing element 31 forms the shut-off device with the valve seat 30 and the closing spring 17 C of the safety valve D, which thanks to the seat valve function in the shut-off position is leak-tight in both flow directions.

Claims (8)

Elektrohydraulische Spannvorrichtung (S), insbesondere für eine Werkzeugmaschine, bei der in einem Einstell-Vorsteuerkreis eines in einem Hauptkreis (6) angeordneten Spanndruckventil (V) ein Proportional-Druckregelventil (B) und zwischen dem Proportional-Druckregelventil (B) und einer Steuerkammer (9) eines Spanndruck-Einstellkolbens (10) ein zwischen einer Durchgangsstellung (c) und einer zumindest in Strömungsrichtung von der Steuerkammer (9) zum Proportional-Druckregelventil (B) leckagefreien Absperrstellung (O) magnetbetätigtes Sicherungsventil (D) angeordnet sind, dadurch gekennzeichnet, dass das Sicherungsventil (D) eine Absperrvorrichtung (C) aufweist, die in der Absperrstellung (O) auch in Strömungsrichtung vom Proportional-Druckregelventil (B) zur Steuerkammer (9) leckagefrei dicht ist.Electro-hydraulic clamping device (S), in particular for a machine tool, in which a proportional pressure regulating valve (B) and between the proportional pressure regulating valve (B) and a control chamber (B) and between the proportional pressure regulating valve (B) and a control pressure control valve (V) arranged in a main circuit (6) 9) a clamping pressure adjusting piston (10) is arranged between a passage position (c) and a leakage-free shut-off position (O) at least in the flow direction from the control chamber (9) to the proportional pressure control valve (B), characterized in that that the safety valve (D) has a shut-off device (C) which in the shut-off position (O) is also leak-tight in the flow direction from the proportional pressure control valve (B) to the control chamber (9). Elektrohydraulische Spannvorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass das Sicherungsventil (D) ein Sitzventil mit einem kugeligen oder kegeligen Schließelement (31) ist, das unter Federkraft (17) bei entregtem Schwarz/Weiß-Schaltmagneten (14) die Absperrstellung (O) einnimmt und in Strömungsrichtung vom Proportional-Druckventil (B) zur Steuerkammer (9) gegen einen Ventilsitz (31) leckagefrei dicht angepresst ist.Electrohydraulic tensioning device according to claim 1, characterized in that the safety valve (D) is a seat valve with a spherical or conical closing element (31), which assumes the shut-off position (O) under spring force (17) when the black / white switching magnet (14) is de-energized and in the flow direction from the proportional pressure valve (B) to the control chamber (9) against a valve seat (31) is tightly pressed leak-free. Elektrohydraulische Spannvorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass das Sicherungsventil (D) und das Proportional-Druckregelventil (B) nebeneinander in einem Kopfteil (19) der Steuerkammer (9) angeordnet sind.Electrohydraulic tensioning device according to claim 1, characterized in that the safety valve (D) and the proportional pressure control valve (B) are arranged side by side in a head part (19) of the control chamber (9). Elektrohydraulische Spannvorrichtung nach Anspruch 3, dadurch gekennzeichnet, dass der Schwarz/Weiß-Schaltmagnet (14) des Sicherungsventils (D) und der Proportionalmagnet (15) des Proportional-Druckregelventils (B) zu einem Doppelmagneten mit gemeinsamen Anschlusssteckem (20) zusammengefasst sind.Electrohydraulic tensioning device according to claim 3, characterized in that the black / white switching magnet (14) of the safety valve (D) and the proportional magnet (15) of the proportional pressure control valve (B) are combined to form a double magnet with a common connector (20). Elektrohydraulische Spannvorrichtung nach wenigstens einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass eine übergeordnete elektronische Steuer- und Überwachungsvorrichtung (3) vorgesehen ist, die eine elektrische, an den Proportionalmagneten (15) und den Schaltmagneten (14) angeschlossene Einstellvorrichtung (5) zum elektrischen Einstellen des Spanndrucks aulweist.Electrohydraulic tensioning device according to at least one of the preceding claims, characterized in that a superordinate electronic control and monitoring device (3) is provided which has an electrical adjusting device (5) connected to the proportional magnet (15) and the switching magnet (14) for the electrical adjustment of the clamping pressure. Elektrohydraulische Spannvorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass ein Analog-Druckaufnehmer (A) zum Abgreifen des Ist-Spanndrucks vorgesehen ist, der, vorzugsweise, an eine vom Hauptkreis (6) getrennte Spanndrucksignalleitung (12) angeschlossen ist.Electrohydraulic clamping device according to claim 1, characterized in that an analog pressure sensor (A) is provided for tapping the actual clamping pressure, which is preferably connected to a clamping pressure signal line (12) separate from the main circuit (6). Elektrohydraulische Spannvorrichtung nach Anspruch 6, dadurch gekennzeichnet, dass der Analog-Druckaufnehmer (A) mit einer Anzeige/Alarm-Einrichtung (4) und/oder der übergeordneten Steuer- und/oder Überwachungsvorrichtung (3) verbunden ist.Electrohydraulic tensioning device according to claim 6, characterized in that the analog pressure sensor (A) is connected to a display / alarm device (4) and / or the higher-level control and / or monitoring device (3). Elektrohydraulische Spannvorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass der Spanndruck-Einstellkolben (10), einen linear verstellbaren Regelkolben (K) des Spanndruckventils (V) entgegengesetzt zu dem hydraulischen Ist-Spanndrucksignal und gegen Federkraft (11) beaufschlagt, dass dem Regelkolben (K) ein elektrischer Schalter (8) zugeordnet ist, der auf einen Schaltpunkt eingestellt ist, der einer auf einen Soll-Spanndruck abgestimmten Position des Regelkolbens (K) entspricht, und dass dem Spanndruckventil (V) im Hauptkreis (6) eine Druckwaage (DW) zugeordnet ist, die in Schließrichtung vom Eingangsdruck und in Öffnungsrichtung vom Ausgangsdruck des Spanndruckventils (V) und einer Feder (22) belastet ist, und die Schaltpunkt-Position des Regelkolbens (K) mengenabhängig macht.Electrohydraulic clamping device according to claim 1, characterized in that the clamping pressure adjusting piston (10) acts on a linearly adjustable regulating piston (K) of the clamping pressure valve (V) in opposition to the hydraulic actual clamping pressure signal and against spring force (11) that the regulating piston (K ) an electrical switch (8) is assigned, which is set to a switching point which corresponds to a position of the control piston (K) matched to a target clamping pressure, and that the clamping pressure valve (V) in the main circuit (6) has a pressure compensator (DW) is assigned, which is loaded in the closing direction by the inlet pressure and in the opening direction by the outlet pressure of the clamping pressure valve (V) and a spring (22), and makes the switching point position of the control piston (K) dependent on the quantity.
EP20030006777 2002-06-10 2003-03-25 Electrohydraulic clamping device Expired - Fee Related EP1371859B1 (en)

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DE20208989U DE20208989U1 (en) 2002-06-10 2002-06-10 Electro-hydraulic clamping device
DE20208989U 2002-06-10

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DE20208989U1 (en) 2003-10-23
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