EP1884853B1 - Hydraulic control valve and electrohydraulic clamping device - Google Patents

Hydraulic control valve and electrohydraulic clamping device Download PDF

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Publication number
EP1884853B1
EP1884853B1 EP06016027A EP06016027A EP1884853B1 EP 1884853 B1 EP1884853 B1 EP 1884853B1 EP 06016027 A EP06016027 A EP 06016027A EP 06016027 A EP06016027 A EP 06016027A EP 1884853 B1 EP1884853 B1 EP 1884853B1
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EP
European Patent Office
Prior art keywords
spring
regulating
valve
hydraulic
regulating valve
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
EP06016027A
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German (de)
French (fr)
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EP1884853A1 (en
Inventor
Georg Neumair
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Hawe Hydraulik SE
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Hawe Hydraulik SE
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Publication date
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Priority to AT06016027T priority Critical patent/ATE422255T1/en
Priority to DE502006002776T priority patent/DE502006002776D1/en
Priority to EP06016027A priority patent/EP1884853B1/en
Publication of EP1884853A1 publication Critical patent/EP1884853A1/en
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Publication of EP1884853B1 publication Critical patent/EP1884853B1/en
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
    • B25B5/00—Clamps
    • B25B5/06—Arrangements for positively actuating jaws
    • B25B5/061—Arrangements for positively actuating jaws with fluid drive
    • 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
    • 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
    • F15B2211/3116—Neutral or centre positions the pump port being open in the centre position, e.g. so-called open 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
    • F15B2211/40—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
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50554—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure downstream of the pressure control means, e.g. pressure reducing 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
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5151—Pressure control characterised by the connections of the pressure control means in the circuit being connected to a pressure source 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
    • F15B2211/52—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
    • F15B2211/70—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
    • F15B2211/7054—Having equal piston areas

Definitions

  • control spring bias can be changed mechanically.
  • it is necessary to adjust the support of the control spring for example via screw.
  • the exact value of the newly set bias voltage is then unknown.
  • a pressure gauge must be used to check which regulated pressure results from the changeover.
  • Such an application is, for example, an electro-hydraulic clamping device of a machine tool (as described Fig. 3 shown), in which it has hitherto been customary to provide two control valves connected in parallel, the control springs are set to certain biases, and switch by means of a 3/2-way solenoid valve between the two control valves to selectively in the tensioner one of two predetermined clamping pressure values adjust.
  • the effort of two control valves each with a spring section is high and costly.
  • the invention has for its object to provide a hydraulic control valve that is structurally simple, inexpensive and reliable, optionally two pre-set, different control spring biases can be set without mechanical manipulation and in an electro-hydraulic tensioner the same function as in the known solution according to Fig. 3 to achieve a structurally simpler way, the safety aspect, which is required by users.
  • the spring abutment can be selectively adjusted hydraulically between two mechanically fixed control spring bias positions associated with a higher and a lower control spring bias, only a single hydraulic control valve controls either a higher or a lower, exactly, depending on the hydraulic actuation of the spring section predetermined outlet pressure. If there is a power failure, the hydraulic loading of the spring section ineffective makes, the bias of the control spring is not completely or indefinitely degraded, but is always due to the mechanical determination, the predetermined higher control spring bias maintained.
  • one of two predetermined control spring biases is normally remotely controlled with the single control valve, namely, a higher or lower control spring bias resulting in a higher or lower clamping pressure in the chuck, the value of each of which is precisely predetermined is.
  • the higher of the two clamping pressures is reliably maintained. In this way, structurally simple and inexpensive, the safety aspect is achieved in the clamping device, as required by many users.
  • the spring section is designed so that the spring abutment automatically holds or assumes the control spring biasing position for the higher control spring bias in case of power failure.
  • the spring abutment is arranged on a tie rod fixed in the control piston.
  • the first stop is arranged on a spring sleeve, which contains a stiffer, preferably prestressed retaining spring than the control spring, and the second stop is arranged on the end of the tension rod facing away from the control spring in the spring sleeve.
  • the main purpose of the retaining spring is to ensure that the spring abutment assumes the higher control spring biasing position in case of a power failure, which eliminates the hydraulic loading of the actuating piston.
  • At least one of the stops is mechanically adjustable in order to set a value for the control spring bias and thus the value of the regulated output pressure in advance can.
  • both attacks are mechanically and independently adjustable, so that both control spring bias values are variable as needed, without affecting each other.
  • the adjusting piston is fixed on the drawbar by a clamping element.
  • the clamping element it may be possible to vary the bias of the retaining spring in a particular area.
  • the spring sleeve with the spring abutment in an outer housing relative to a predetermined position in the outer housing position for the highest possible control spring bias voltage can be screwed.
  • the first stop is set in the desired position.
  • the second stop is arranged on a screw-threaded in the spring sleeve, so that the position of the second stop can be selected regardless of the position of the first stop.
  • a 3/2-way magnetic seat valve is expediently arranged, which can be fed with supply pressure, preferably via a housed in the outer housing supply channel, which may be connected to a pressure port of the control valve.
  • the supply channel could be acted upon from another source of pressure.
  • a hydraulic control valve R of in Fig. 2 The type of construction shown can generally be any control valve that operates with a control spring, such as a pressure reducing valve or a pressure relief valve, and is useful in hydraulic systems, of which, for example, an electro-hydraulic tensioning device in Fig. 1 is selected.
  • a control spring such as a pressure reducing valve or a pressure relief valve
  • An electrohydraulic tensioning device S in Fig. 1 can be used on a machine tool to clamp workpieces, for example, workpieces that require two different clamping pressures for clamping during machining.
  • a in the embodiment shown double-acting hydraulic clamping cylinder 1 is connected via working lines 2, 3 to a directional control valve 4 (2/2-solenoid control valve), of which one line leads to a tank line 6 on the one hand.
  • a connection of the directional control valve 4 is connected via a line 7 to the hydraulic control valve R, which in turn is in communication with the pump line 5 and the tank line 6.
  • a 3/2-way solenoid valve (seat valve) is arranged, and connected to the pump line 5 and the tank line 6.
  • the 3/2-way magnetic switching valve 8 has a black / white magnet 9 and a return spring 15 and is connected via a line to a control chamber of a control piston 13.
  • With the adjusting piston 13 is a spring abutment 12 in connection, on which a control spring 11 is supported, which acts on a valve member 10 of the control valve R with a certain bias.
  • a retaining spring 14 which is stiffer than the control spring 11. At least the bias of the control spring 11 is adjustable. Further, the bias of the control spring 11 can be changed by means of the 3/2-way magnetic switching valve 8 between two predetermined bias values, which are associated with a higher and a lower clamping pressure for the clamping cylinder 1.
  • Fig. 3 Prior art
  • two hydraulic control valves R1, R2 eg pressure reducing valves
  • the control valve R1 a biasing spring 11 '
  • the Valve member 10a with the higher biasing force applied higher clamping pressure
  • the other control valve R2 has a less-biased control spring 11 ", which acts on the valve member 10b (lower clamping pressure.
  • the 3/2-way solenoid valve 8 ' connects in the switching position shown (De-energized) the output of the first control valve R1 to the line 7 (higher clamping pressure), in the energized state, however, the output of the other control valve R2 to the line 7 (lower clamping pressure).
  • Fig. 2 shows in axial section a hydraulic control valve R, which is formed for example as a pressure reducing valve, and inter alia for the electro-hydraulic tensioning device in Fig. 1 can be used.
  • the valve member 10 is acted upon by the control spring 11, which is supported on the spring abutment 12.
  • the spring abutment 12 is connected via a pull rod 23 with the actuating piston 13, which is fixed on the pull rod 23 by a clamping element 22.
  • the actuating piston 13 is slidably housed in a control chamber 30 of a spring sleeve 18 which includes a retaining spring 14.
  • the retaining spring 14 is, optionally, biased, and stiffer than the control spring 11.
  • the retaining spring is supported between a stop in the spring sleeve 18 and the back of the spring plate 12 so that it determines the position of the spring abutment 12 relative to the spring sleeve 18.
  • the spring sleeve 18 is screwed with a thread in an internal thread 17 of an outer housing 14 and defines a first stop 28 for the actuating piston 13.
  • the first stop 28 determines the position of the spring abutment 12 in relation to the outer housing 16, as long as the actuating piston 13 is not acted upon.
  • a further stop 29 is formed, which defines the position of the spring abutment 12 for the highest possible bias of the control spring 11.
  • a screw 20 is screwed, which defines a second stop 21 for the left-side end of the pull rod 23 and the actuator piston 13.
  • the position of the spring abutment 12 relative to the outer housing 16 determines the lower preload of the control spring 11.
  • the threaded portions 17, 19 are sealed because the control chamber 30 is sealed via a supply channel 27 is connected to a supply port 26 of the outer housing 16 in order to pressurize or relieve the control chamber 30 can.
  • the 3/2-way solenoid valve 8 is externally attached to the outer housing 16 and is connected to a tank port 25 in the outer housing 16, via which the interior of the spring sleeve 18 is relieved of pressure. Furthermore, the solenoid valve 8 is connected to a supply connection, not shown, which runs, for example, in the interior of the outer housing 16 and leads to the pressure connection of the control valve or valve member 10.
  • This spring section F of the control valve R not only makes it possible to switch hydraulically from the setting of the higher preload pressure of the control spring to the setting for the lower preload pressure (when the actuating piston 13 is acted upon), but also allows the positions of the stops 21, 28 individually and independently adjustable, either by screwing the screw 20 relative to the spring sleeve 18 and / or by screwing the spring sleeve 18 relative to the outer housing 16 to set two specific output pressures of the control valve in advance.
  • the pressure supply for acting on the actuating piston 13 could also come from a different pressure source than from the pressure connection of the control valve.
  • the higher control spring preload (higher clamping pressure in the tensioning device) is automatically set, because when the control piston 13 engages Stop 28, the position of the spring abutment 12 is set and held by the retaining spring 14 in the spring sleeve 18.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Engineering & Computer Science (AREA)
  • Safety Valves (AREA)
  • Support Of The Bearing (AREA)
  • Forklifts And Lifting Vehicles (AREA)
  • Jib Cranes (AREA)
  • Vehicle Body Suspensions (AREA)

Abstract

The valve (R) has a control spring (11) loading a valve unit (10) and supported at a spring thrust bearing (12). The thrust bearing is hydraulically adjustable between two mechanically determined control spring-clamping positions by using a setting piston (13), where the positions are assigned to higher and lower control spring-clamping. The piston is fixed to a connecting rod by using a clamping unit, and is arranged in a control chamber that is provided in a spring housing (18), where the control chamber is connected with a pressure connection of an outer housing.

Description

Die Erfindung betrifft ein Hydraulik-Regelventil gemäß dem Oberbegriff des Patentanspruchs 1, sowie eine elektrohydraulische Spannvorrichtung gemäß dem Oberbegriff des Patentanspruchs 10.The invention relates to a hydraulic control valve according to the preamble of patent claim 1, and to an electro-hydraulic tensioning device according to the preamble of claim 10.

Bei eine Regelfeder enthaltenden Hydraulik-Regelventilen bekannter Bauart lässt sich die Regelfeder-Vorspannung mechanisch ändern. Dazu ist es erforderlich, die Abstützung der Regelfeder beispielsweise über Schraubverbindungen zu verstellen. Der exakte Wert der neu eingestellten Vorspannung ist dann nicht bekannt. Es muss beispielsweise über ein Manometer überprüft werden, welcher geregelter Druck sich aus der Umstellung ergibt. Es besteht bei solchen Hydraulik-Regelventilen, insbesondere bei Druckminder- oder Druckbegrenzungsventilen, ein Bedarf, bei manchen Einsatzfällen eine rasche Umstellung der Regelfeder-Vorspannung zwischen zwei genau bekannten Vorspannwerten vornehmen zu können.In a control spring containing hydraulic control valves of known type, the control spring bias can be changed mechanically. For this purpose, it is necessary to adjust the support of the control spring, for example via screw. The exact value of the newly set bias voltage is then unknown. For example, a pressure gauge must be used to check which regulated pressure results from the changeover. There is a need in such hydraulic control valves, especially in pressure reducing or pressure limiting valves, to be able to make a rapid changeover of the control spring bias between two well-known bias values in some applications.

Ein solcher Einsatzfall ist beispielsweise eine elektrohydraulische Spannvorrichtung einer Werkzeugmaschine (wie anhand Fig. 3 gezeigt), bei der es bisher üblich ist, zwei parallel geschaltete Regelventile vorzusehen, deren Regelfedern auf bestimmte Vorspannungen eingestellt sind, und mittels eines 3/2-Wege-Magnetventils zwischen den beiden Regelventilen umzuschalten, um in der Spannvorrichtung wahlweise einen von zwei vorbestimmten Spanndruckwerten einzustellen. Der Aufwand zweier Regelventile jeweils mit einer Federsektion ist hoch und kostenintensiv.Such an application is, for example, an electro-hydraulic clamping device of a machine tool (as described Fig. 3 shown), in which it has hitherto been customary to provide two control valves connected in parallel, the control springs are set to certain biases, and switch by means of a 3/2-way solenoid valve between the two control valves to selectively in the tensioner one of two predetermined clamping pressure values adjust. The effort of two control valves each with a spring section is high and costly.

Es ist zwar bei elektrohydraulischen Spannvorrichtungen von Werkzeugmaschinen bekannt, den durch ein Regelventil eingestellten Spanndruck elektrisch zu ändern. Hierfür wird ein die Regelfeder abstützender Stellkolben mit einem bestimmten Steuerdruck beaufschlagt, der die jeweilige Regelfeder-Vorspannung erzeugt, und für den Stellkolben eine relativ aufwendige Ventilkombination mit wenigstens einem elektrisch ansteuerbaren Proportional-Druckregelventil vorzusehen. Diese Lösung ist schaltungstechnisch aufwendig und kostenintensiv. Ferner besteht die Gefahr, dass bei einem Stromausfall der Spanndruck vollständig zusammenbricht, was in vielen Fällen nicht zulässig ist, oder dieser Nachteil nur dadurch umgangen werden kann, dass ein zusätzliches Sicherungsventil eingegliedert wird, das bei einem Stromausfall den für den Stellkolben eingestellten Steuerdruck hält.Although it is known in electro-hydraulic clamping devices of machine tools to change the set by a control valve clamping pressure electrically. For this purpose, a control spring supporting the adjusting piston is acted upon by a certain control pressure, which generates the respective control spring bias, and provide for the control piston a relatively complex valve combination with at least one electrically controllable proportional pressure control valve. This solution is circuitry expensive and expensive. Furthermore, there is a risk that in the event of a power failure the clamping pressure completely collapses, which is not permissible in many cases, or this disadvantage can only be avoided by the fact that an additional safety valve is incorporated, which holds the control pressure set for the actuator piston in the event of a power failure.

Bei einem gattungsgemäßen Hydraulik-Regelventil und einer gattungsgemäßen elektrohydraulischen Spannvorrichtung für eine Werkzeugmaschine gemäß DE 36 25 222 A wird bei einem Ausfall der hydraulischen Beaufschlagung des Stellkolbens aufgrund Stromausfalls entweder die Regelfeder-Vorspannposition für die niedrigere Regelfeder-Vorspannung von dem Federwiderlager gehalten oder wird das Federwiderlager selbsttätig in die Regelfeder-Vorspannposition für die niedrigere Regelfeder-Vorspannung gebracht. Der Stellkolben wird nämlich bei Hydraulikbeaufschlagung gegen den Anschlag gebracht, der die höhere Regelfeder-Vorspannung definiert, wobei die Regelfeder am Stellkolben wirkt. Fällt die Hydraulikbeaufschlagung des Stellkolbens aufgrund Stromausfalls weg, dann stellt die Regelfeder des Stellkolbens gegen den anderen Anschlag, der die niedrigere Regelfeder-Vorspannung definiert. Damit lässt sich jedoch der Sicherheitsaspekt für die Spannvorrichtung der Werkzeugmaschine nicht erzielen, der von vielen Anwendern gefordert wird, nämlich die Einstellung des höheren Spanndrucks.In a generic hydraulic control valve and a generic electro-hydraulic clamping device for a machine tool according to DE 36 25 222 A in case of failure of the hydraulic actuation of the actuating piston due to power failure, either the control spring biasing position for the lower control spring bias of the spring abutment held or the spring abutment is automatically brought into the control spring biasing position for the lower control spring bias. The actuator piston is in fact brought against the stop when hydraulic loading, which defines the higher control spring bias, the control spring acts on the actuator piston. If the hydraulic load of the actuating piston falls due to power failure, then the control spring of the actuating piston against the other stop, which defines the lower control spring bias. However, this can not achieve the safety aspect for the clamping device of the machine tool, which is required by many users, namely the setting of the higher clamping pressure.

Der Erfindung liegt die Aufgabe zugrunde, ein Hydraulik-Regelventil anzugeben, das baulich einfach, kostengünstig und betriebssicher ist, wahlweise zwei vorab festgelegte, unterschiedliche Regelfeder-Vorspannungen ohne mechanische Manipulationen einstellen lässt und bei einer elektrohydraulischen Spannvorrichtung die gleiche Funktion wie bei der bekannten Lösung gemäß Fig. 3 auf baulich einfachere Weise zu erzielen, den Sicherheitsaspekt, der von Anwendern gefordert wird.The invention has for its object to provide a hydraulic control valve that is structurally simple, inexpensive and reliable, optionally two pre-set, different control spring biases can be set without mechanical manipulation and in an electro-hydraulic tensioner the same function as in the known solution according to Fig. 3 to achieve a structurally simpler way, the safety aspect, which is required by users.

Die gestellte Aufgabe wird mit den Merkmalen des Patentanspruchs 1 und des Patentanspruchs 10 gelöst.The stated object is achieved with the features of patent claim 1 and claim 10.

Dass sich das Federwiderlager wahlweise hydraulisch zwischen zwei mechanisch festgelegten Regelfeder-Vorspannpositionen verstellen lässt, die einer höheren und einer niedrigeren Regelfeder-Vorspannung zugeordnet sind, regelt nur ein einziges Hydraulik-Regelventil abhängig von der hydraulischen Betätigung der Federsektion entweder einen höheren oder einen niedrigeren, exakt vorherbestimmten Ausgangsdruck. Wenn es zu einem Stromausfall kommt, der die Hydraulikbeaufschlagung der Federsektion wirkungslos macht, wird die Vorspannung der Regelfeder nicht vollständig oder auf unbestimmte Weise abgebaut, sondern wird bzw. bleibt aufgrund der mechanischen Festlegung stets die vorbestimmte höhere Regelfeder-Vorspannung aufrechtgehalten.The fact that the spring abutment can be selectively adjusted hydraulically between two mechanically fixed control spring bias positions associated with a higher and a lower control spring bias, only a single hydraulic control valve controls either a higher or a lower, exactly, depending on the hydraulic actuation of the spring section predetermined outlet pressure. If there is a power failure, the hydraulic loading of the spring section ineffective makes, the bias of the control spring is not completely or indefinitely degraded, but is always due to the mechanical determination, the predetermined higher control spring bias maintained.

In der elektrohydraulischen Spannvorrichtung wird normalerweise mit dem einzigen Regelventil wahlweise eine von zwei vorbestimmten Regelfeder-Vorspannungen femgesteuert eingestellt, und zwar eine höhere oder eine niedrigere Regelfeder-Vorspannung, aus denen ein höherer oder ein niedrigerer Spanndruck in der Spannvorrichtung resultiert, dessen Wert jeweils genau vorbestimmt ist. Bei einem Stromausfall, der das Magnetventil betrifft, wird zuverlässig der höhere der beiden Spanndrücke gehalten. Auf diese Weise wird baulich einfach und kostengünstig der Sicherheitsaspekt in der Spannvorrichtung erzielt, wie er von vielen Anwendern gefordert ist.In the electrohydraulic tensioner, one of two predetermined control spring biases is normally remotely controlled with the single control valve, namely, a higher or lower control spring bias resulting in a higher or lower clamping pressure in the chuck, the value of each of which is precisely predetermined is. In the event of a power failure affecting the solenoid valve, the higher of the two clamping pressures is reliably maintained. In this way, structurally simple and inexpensive, the safety aspect is achieved in the clamping device, as required by many users.

Um gegebenen Sicherheitsanforderungen gerecht zu werden, ist die Federsektion so ausgebildet, dass das Federwiderlager bei einem Stromausfall selbsttätig die Regelfeder-Vorspannposition für die höhere Regelfeder-Vorspannung hält oder einnimmt. Bei einer elektrohydraulischen Spannvorrichtung für eine Werkzeugmaschine ist es im Regelfall wichtig, bei einem Stromausfall aus Sicherheitsgründen die höhere Regelfeder-Vorspannung und damit das Halten des höheren Spanndrucks sicherzustellen. Das Federwiderlager ist an einer im Stellkolben festgelegten Zugstange angeordnet. Für den Stellkolben ist der erste Anschlag an einer Federhülse angeordnet, die eine steifere, vorzugsweise vorgespannte Haltefeder als die Regelfeder enthält, und ist der zweite Anschlag an der der Regelfeder abgewandten Endseite der Zugstange in der Federhülse angeordnet. Der Hauptzweck der Haltefeder besteht darin, bei einem Stromausfall, der die hydraulische Beaufschlagung des Stellkolbens entfallen lässt, sicherzustellen, dass das Federwiderlager die höhere Regelfeder-Vorspannposition einnimmt.To meet given safety requirements, the spring section is designed so that the spring abutment automatically holds or assumes the control spring biasing position for the higher control spring bias in case of power failure. In an electro-hydraulic clamping device for a machine tool, it is usually important to ensure the higher control spring bias and thus holding the higher clamping pressure in case of power failure for safety reasons. The spring abutment is arranged on a tie rod fixed in the control piston. For the adjusting piston, the first stop is arranged on a spring sleeve, which contains a stiffer, preferably prestressed retaining spring than the control spring, and the second stop is arranged on the end of the tension rod facing away from the control spring in the spring sleeve. The main purpose of the retaining spring is to ensure that the spring abutment assumes the higher control spring biasing position in case of a power failure, which eliminates the hydraulic loading of the actuating piston.

Zweckmäßig ist zumindest einer der Anschläge mechanisch einstellbar, um einen Wert für die Regelfeder-Vorspannung und damit den Wert des geregelten Ausgangsdrucks vorab einstellen zu können. Zweckmäßig sind sogar beide Anschläge mechanisch und unabhängig voneinander einstellbar, so dass beide Regelfeder-Vorspannungswerte nach Bedarf variierbar sind, ohne einander zu beeinflussen.Suitably, at least one of the stops is mechanically adjustable in order to set a value for the control spring bias and thus the value of the regulated output pressure in advance can. Suitably, even both attacks are mechanically and independently adjustable, so that both control spring bias values are variable as needed, without affecting each other.

Aus montagetechnischen Gründen wird hierbei der Stellkolben auf der Zugstange durch ein Spannelement festgelegt. Mittels des Spannelementes ist es gegebenenfalls möglich, auch die Vorspannung der Haltefeder in einem bestimmten Bereich zu variieren.For assembly reasons, in this case the adjusting piston is fixed on the drawbar by a clamping element. By means of the clamping element, it may be possible to vary the bias of the retaining spring in a particular area.

Zweckmäßig ist die Federhülse mit dem Federwiderlager in einem Außengehäuse relativ zu einer im Außengehäuse vorgegebenen Position für die höchstmögliche Regelfeder-Vorspannung verschraubbar. Durch Verschrauben der Federhülse wird der erste Anschlag in die jeweils gewünschte Position eingestellt.Advantageously, the spring sleeve with the spring abutment in an outer housing relative to a predetermined position in the outer housing position for the highest possible control spring bias voltage can be screwed. By screwing the spring sleeve, the first stop is set in the desired position.

Der zweite Anschlag ist an einem in der Federhülse vorschraubbaren Schraubeinsatz angeordnet, so dass sich auch die Position des zweiten Anschlages unabhängig von der Position des ersten Anschlags wählen lässt.The second stop is arranged on a screw-threaded in the spring sleeve, so that the position of the second stop can be selected regardless of the position of the first stop.

In der Federhülse ist zweckmäßig beim ersten Anschlag die Steuerkammer für den Stellkolben vorgesehen, die über einen den Gewindebereich durchsetzenden Kanal mit einem Druckanschluss des Außengehäuses verbunden ist.In the spring sleeve, the control chamber for the actuating piston is expediently provided at the first stop, which is connected via a thread passing through the channel with a pressure port of the outer housing.

Auf dem Außengehäuse ist zweckmäßig ein 3/2-Wege-Magnetsitzventil angeordnet, das mit Versorgungsdruck speisbar ist, vorzugsweise über einen im Außengehäuse untergebrachten Versorgungskanal, der an einen Druckanschluss des Regelventils angeschlossen sein kann. Alternativ könnte der Versorgungskanal auch aus einer anderen Druckquelle beaufschlagt werden.On the outer housing a 3/2-way magnetic seat valve is expediently arranged, which can be fed with supply pressure, preferably via a housed in the outer housing supply channel, which may be connected to a pressure port of the control valve. Alternatively, the supply channel could be acted upon from another source of pressure.

Anhand der Zeichnungen werden Ausführungsformen des Erfindungsgegenstandes sowie ein Beispiel aus dem Stand der Technik erläutert. Es zeigen:

Fig. 1
ein Blockschaltbild einer elektrohydraulischen Spannvorrichtung, beispielsweise einer Werkzeugmaschine, mit einem erfindungsgemäßen Regelventil,
Fig. 2
einen Achsschnitt des Regelventils, und
Fig. 3
ein Blockschaltbild einer bekannten elektrohydraulischen Spannvorrichtung (Stand der Technik).
With reference to the drawings, embodiments of the subject invention and an example of the prior art will be explained. Show it:
Fig. 1
1 is a block diagram of an electro-hydraulic tensioning device, for example a machine tool, with a control valve according to the invention;
Fig. 2
an axial section of the control valve, and
Fig. 3
a block diagram of a known electro-hydraulic tensioning device (prior art).

Ein Hydraulik-Regelventil R der in Fig. 2 gezeigten Bauart kann allgemein jedes Regelventil sein, das mit einer Regelfeder arbeitet, beispielsweise ein Druckminderventil oder ein Druckbegrenzungsventil, und ist zweckmäßig einsetzbar in Hydrauliksystemen, von denen als Beispiel eine elektrohydraulische Spannvorrichtung in Fig. 1 ausgewählt ist. Diese Beispiele sowohl für das Regelventil als auch das System, in dem das Regelventil verwendbar ist, sind jedoch hier nicht beschränkend aufgezählt.A hydraulic control valve R of in Fig. 2 The type of construction shown can generally be any control valve that operates with a control spring, such as a pressure reducing valve or a pressure relief valve, and is useful in hydraulic systems, of which, for example, an electro-hydraulic tensioning device in Fig. 1 is selected. However, these examples for both the control valve and the system in which the control valve is usable are not listed here in a restrictive manner.

Eine elektrohydraulische Spannvorrichtung S in Fig. 1 kann an einer Werkzeugmaschine verwendet werden, um Werkstücke zu spannen, und zwar beispielsweise Werkstücke, die zum Spannen bei der Bearbeitung zwei verschiedene Spanndrücke benötigen. Ein in der gezeigten Ausführungsform doppelt wirkender Hydraulik-Spannzylinder 1 ist über Arbeitsleitungen 2, 3 an ein Richtungs-Steuerventil 4 (2/2-Magnetsteuerventil) angeschlossen, von dem einerseits eine Leitung zu einer Tankleitung 6 führt.An electrohydraulic tensioning device S in Fig. 1 can be used on a machine tool to clamp workpieces, for example, workpieces that require two different clamping pressures for clamping during machining. A in the embodiment shown double-acting hydraulic clamping cylinder 1 is connected via working lines 2, 3 to a directional control valve 4 (2/2-solenoid control valve), of which one line leads to a tank line 6 on the one hand.

Ein Anschluss des Richtungs-Steuerventils 4 ist über eine Leitung 7 an das hydraulische Regelventil R angeschlossen, das seinerseits mit der Pumpenleitung 5 und der Tankleitung 6 in Verbindung ist. Parallel zum Regelventil R ist ein 3/2-Wege-Magnetschaltventil (Sitzventil) angeordnet, und an die Pumpenleitung 5 und die Tankleitung 6 angeschlossen. Das 3/2-Wege-Magnetschaltventil 8 weist einen Schwarz/Weiß-Magneten 9 und eine Rückstellfeder 15 auf und ist über eine Leitung an eine Steuerkammer eines Stellkolbens 13 angeschlossen. Mit dem Stellkolben 13 steht ein Federwiderlager 12 in Verbindung, an dem sich eine Regelfeder 11 abstützt, die mit einer bestimmten Vorspannung ein Ventilglied 10 des Regelventils R beaufschlagt. An der anderen Seite des Stellkolbens 13 wirkt eine Haltefeder 14, die steifer ist als die Regelfeder 11. Zumindest die Vorspannung der Regelfeder 11 ist einstellbar. Ferner lässt sich die Vorspannung der Regelfeder 11 mittels des 3/2-Wege-Magnetschaltventils 8 zwischen zwei vorbestimmten Vorspannwerten verändern, die einem höheren und einem niedrigeren Spanndruck für den Spannzylinder 1 zugeordnet sind.A connection of the directional control valve 4 is connected via a line 7 to the hydraulic control valve R, which in turn is in communication with the pump line 5 and the tank line 6. Parallel to the control valve R, a 3/2-way solenoid valve (seat valve) is arranged, and connected to the pump line 5 and the tank line 6. The 3/2-way magnetic switching valve 8 has a black / white magnet 9 and a return spring 15 and is connected via a line to a control chamber of a control piston 13. With the adjusting piston 13 is a spring abutment 12 in connection, on which a control spring 11 is supported, which acts on a valve member 10 of the control valve R with a certain bias. On the other side of the actuating piston 13 acts a retaining spring 14, which is stiffer than the control spring 11. At least the bias of the control spring 11 is adjustable. Further, the bias of the control spring 11 can be changed by means of the 3/2-way magnetic switching valve 8 between two predetermined bias values, which are associated with a higher and a lower clamping pressure for the clamping cylinder 1.

In der in Fig. 1 gezeigten Schaltstellung ist der Stellkolben 13 entlastet, so dass dank der Wirkung der Haltefeder 14 die Regelfeder 11 auf den Wert für die höhere Vorspannung und damit für den höheren Spanndruck eingestellt ist. Der Magnet 9 ist entregt.In the in Fig. 1 shown switching position of the actuating piston 13 is relieved, so that thanks to the action of the retaining spring 14, the control spring 11 is set to the value for the higher bias voltage and thus for the higher clamping pressure. The magnet 9 is de-energized.

Wird für die andere Schaltstellung der Magnet 9 erregt, dann wird der Stellkolben 13 in Fig. 1 nach rechts verstellt, so dass die niedrigere Regelfeder-Vorspannung eingestellt wird (niedrigerer Spanndruck). Die niedrigere Vorspannung der Regelfeder 11 ist jedoch so hoch, dass in keinem Fall der Spanndruck vollständig zusammenbricht oder in nicht kontrollierter Weise zu stark abfällt.If the magnet 9 is energized for the other switching position, then the actuating piston 13 in Fig. 1 adjusted to the right, so the lower control spring preload set becomes (lower clamping pressure). However, the lower bias of the control spring 11 is so high that in no case completely collapses the clamping pressure or falls too much in an uncontrolled manner.

Die gleiche Funktion wie in Fig. 1 wird bei einer bekannten Lösung (Fig. 3 Stand der Technik) dadurch erzielt, dass zwischen der Pumpenleitung 5, der Tankleitung 6 und dem Richtungs-Steuerventil 4 zwei Hydraulik-Regelventile R1, R2 (z.B. Druckminderventile) parallel angeordnet sind, von denen das Regelventil R1 eine Vorspannfeder 11' aufweist, die das Ventilglied 10a mit der höheren Vorspannkraft beaufschlagt (höherer Spanndruck), während das andere Regelventil R2 eine weniger vorgespannte Regelfeder 11" aufweist, die das Ventilglied 10b beaufschlagt (niedrigerer Spanndruck). Das 3/2-Wege-Magnetschaltventil 8' verbindet in der gezeigten Schaltstellung (entregt) den Ausgang des ersten Regelventils R1 mit der Leitung 7 (höherer Spanndruck), in erregtem Zustand hingegen den Ausgang des anderen Regelventils R2 mit der Leitung 7 (niedrigerer Spanndruck).The same function as in Fig. 1 is in a known solution ( Fig. 3 Prior art) achieved in that between the pump line 5, the tank line 6 and the directional control valve 4, two hydraulic control valves R1, R2 (eg pressure reducing valves) are arranged in parallel, of which the control valve R1, a biasing spring 11 ', the Valve member 10a with the higher biasing force applied (higher clamping pressure), while the other control valve R2 has a less-biased control spring 11 ", which acts on the valve member 10b (lower clamping pressure.) The 3/2-way solenoid valve 8 'connects in the switching position shown (De-energized) the output of the first control valve R1 to the line 7 (higher clamping pressure), in the energized state, however, the output of the other control valve R2 to the line 7 (lower clamping pressure).

Bei beiden Lösungen in den Fig. 1 und 3 führt ein Ausfall der Strombeaufschlagung des 3/2-Wege-Magnetschaltventils 8 bzw. 8' dazu, dass automatisch der höhere Spanndruck gehalten wird. Allerdings sind hierfür in Fig. 3 die beiden Regelventile mit jeweils einer eigenen Federsektion erforderlich, was einen relativ hohen Aufwand bedingt, während in Fig. 1 mit einem einzigen Regelventil R (z.B. einem Druckminderventil oder Druckbegrenzungsventil) ausgekommen wird.For both solutions in the Fig. 1 and 3 leads a failure of the current application of the 3/2-way solenoid valve 8 and 8 'to automatically the higher clamping pressure is maintained. However, these are in Fig. 3 the two control valves, each with its own spring section required, which requires a relatively high effort while in Fig. 1 with a single control valve R (eg a pressure reducing valve or pressure relief valve) is getting along.

Fig. 2 zeigt im Achsschnitt ein Hydraulik-Regelventil R, das beispielsweise als Druckminderventil ausgebildet ist, und unter anderem für die elektrohydraulische Spannvorrichtung in Fig. 1 verwendet werden kann. Das Ventilglied 10 wird von der Regelfeder 11 beaufschlagt, die sich an dem Federwiderlager 12 abstützt. Das Federwiderlager 12 ist über eine Zugstange 23 mit dem Stellkolben 13 verbunden, der auf der Zugstange 23 durch ein Spannelement 22 festgelegt ist. Der Stellkolben 13 ist in einer Steuerkammer 30 einer Federhülse 18 verschiebbar untergebracht, die eine Haltefeder 14 enthält. Die Haltefeder 14 ist, gegebenenfalls, vorgespannt, und steifer als die Regelfeder 11. Die Haltefeder stützt sich zwischen einem Anschlag in der Federhülse 18 und der Rückseite des Federtellers 12 ab, so dass sie die Position des Federwiderlagers 12 relativ zur Federhülse 18 festlegt. Die Federhülse 18 ist mit einem Gewinde in einem Innengewinde 17 eines Außengehäuses 14 verschraubbar und definiert einen ersten Anschlag 28 für den Stellkolben 13. Der erste Anschlag 28 bestimmt die Position des Federwiderlagers 12 in Relation zum Außengehäuse 16, solange der Stellkolben 13 nicht beaufschlagt ist. Fig. 2 shows in axial section a hydraulic control valve R, which is formed for example as a pressure reducing valve, and inter alia for the electro-hydraulic tensioning device in Fig. 1 can be used. The valve member 10 is acted upon by the control spring 11, which is supported on the spring abutment 12. The spring abutment 12 is connected via a pull rod 23 with the actuating piston 13, which is fixed on the pull rod 23 by a clamping element 22. The actuating piston 13 is slidably housed in a control chamber 30 of a spring sleeve 18 which includes a retaining spring 14. The retaining spring 14 is, optionally, biased, and stiffer than the control spring 11. The retaining spring is supported between a stop in the spring sleeve 18 and the back of the spring plate 12 so that it determines the position of the spring abutment 12 relative to the spring sleeve 18. The spring sleeve 18 is screwed with a thread in an internal thread 17 of an outer housing 14 and defines a first stop 28 for the actuating piston 13. The first stop 28 determines the position of the spring abutment 12 in relation to the outer housing 16, as long as the actuating piston 13 is not acted upon.

Im Außengehäuse 16 ist ein weiterer Anschlag 29 geformt, der die Position des Federwiderlagers 12 für die höchstmögliche Vorspannung der Regelfeder 11 definiert. In einem Innengewinde 19 der Federhülse 18 ist ein Schraubeinsatz 20 verschraubbar, der einen zweiten Anschlag 21 für das linksseitige Ende der Zugstange 23 bzw. den Stellkolben 13 definiert. Bei Anlage der Zugstange 23 an dem zweiten Anschlag 21 (bei Beaufschlagung des Stellkolbens 13) bestimmt die Position des Federwiderlagers 12 relativ zum Außengehäuse 16 die niedrigere Vorspannung der Regelfeder 11. Die Gewindebereiche 17, 19 sind abgedichtet, weil die Steuerkammer 30 über einen Versorgungskanal 27 mit einem Versorgungsanschluss 26 des Außengehäuses 16 verbunden ist, um die Steuerkammer 30 mit Druck beaufschlagen oder entlasten zu können. Das 3/2-Wege-Magnetschaltventil 8 ist außen an das Außengehäuse 16 angebaut und ist mit einem Tankanschluss 25 im Außengehäuse 16 verbunden, über den auch der Innenraum der Federhülse 18 druckentlastet wird. Ferner steht das Magnetventil 8 mit einem nicht gezeigten Versorgungsanschluss in Verbindung, der beispielsweise im Inneren des Außengehäuses 16 verläuft und zum Druckanschluss des Regelventils bzw. Ventilglieds 10 führt.In the outer housing 16, a further stop 29 is formed, which defines the position of the spring abutment 12 for the highest possible bias of the control spring 11. In an internal thread 19 of the spring sleeve 18, a screw 20 is screwed, which defines a second stop 21 for the left-side end of the pull rod 23 and the actuator piston 13. When the pull rod 23 abuts against the second stop 21 (when the actuating piston 13 is acted upon), the position of the spring abutment 12 relative to the outer housing 16 determines the lower preload of the control spring 11. The threaded portions 17, 19 are sealed because the control chamber 30 is sealed via a supply channel 27 is connected to a supply port 26 of the outer housing 16 in order to pressurize or relieve the control chamber 30 can. The 3/2-way solenoid valve 8 is externally attached to the outer housing 16 and is connected to a tank port 25 in the outer housing 16, via which the interior of the spring sleeve 18 is relieved of pressure. Furthermore, the solenoid valve 8 is connected to a supply connection, not shown, which runs, for example, in the interior of the outer housing 16 and leads to the pressure connection of the control valve or valve member 10.

Diese Federsektion F des Regelventils R ermöglicht es nicht nur, wahlweise hydraulisch von der Einstellung des höheren Vorspanndrucks der Regelfeder auf die Einstellung für den niedrigeren Vorspanndruck umzustellen (bei Beaufschlagen des Stellkolbens 13), sondern lässt es auch zu, die Positionen der Anschläge 21, 28 individuell und voneinander unabhängig zu verstellen, und zwar entweder durch Verschrauben des Schraubeinsatzes 20 relativ zur Federhülse 18 und/oder durch Verschrauben der Federhülse 18 relativ zum Außengehäuse 16, um vorab zwei bestimmte Ausgangsdrücke des Regelventils festzulegen.This spring section F of the control valve R not only makes it possible to switch hydraulically from the setting of the higher preload pressure of the control spring to the setting for the lower preload pressure (when the actuating piston 13 is acted upon), but also allows the positions of the stops 21, 28 individually and independently adjustable, either by screwing the screw 20 relative to the spring sleeve 18 and / or by screwing the spring sleeve 18 relative to the outer housing 16 to set two specific output pressures of the control valve in advance.

Die Druckversorgung zur Beaufschlagung des Stellkolbens 13 könnte auch von einer anderen Druckquelle als vom Druckanschluss des Regelventils kommen.The pressure supply for acting on the actuating piston 13 could also come from a different pressure source than from the pressure connection of the control valve.

Bei einem Stromausfall wird automatisch die höhere Regelfeder-Vorspannung (höherer Spanndruck in der Spannvorrichtung) eingestellt, weil bei Anlage des Stellkolbens 13 am Anschlag 28 die Position des Federwiderlagers 12 von der Haltefeder 14 in der Federhülse 18 eingestellt und gehalten wird.In the event of a power failure, the higher control spring preload (higher clamping pressure in the tensioning device) is automatically set, because when the control piston 13 engages Stop 28, the position of the spring abutment 12 is set and held by the retaining spring 14 in the spring sleeve 18.

Claims (10)

  1. Hydraulic regulating valve (R), in particular pressure-reducing valve or pressure-limiting valve, having a spring section (F) which comprises a regulating spring (11) which loads a valve element (10) and is supported on a spring abutment (12), it being possible for the spring abutment (12) to be adjusted optionally hydraulically via an adjusting piston (13), in order to change its prestress of the regulating spring (11), between two regulating-spring prestressing positions which are fixed mechanically by stops (21, 28) and are assigned to a higher and a lower regulating-spring prestress, characterized in that, if the hydraulic loading of the adjusting piston (13) fails on account of a power failure, the spring abutment (12) can be moved automatically into the regulating-spring prestressing position for the higher regulating-spring prestress or can be held in the said position.
  2. Hydraulic regulating valve according to Claim 1, characterized in that the spring abutment (12) is arranged on a pull rod (23) which is fixed in the adjusting piston (13), in that the first stop (28) which faces the regulating spring (11) and the valve element (10) for the adjusting piston (13) is arranged on a spring sleeve (18) which comprises a more rigid holding spring (14) than the regulating spring (11), which holding spring (14) is inserted with prestress between the first stop (28) and the spring abutment (11), and in that the second stop (21) is arranged in the spring sleeve (18) on that end side of the pull rod (23) which faces away from the regulating spring (11).
  3. Hydraulic regulating valve according to Claim 1, characterized in that one or both stops (21, 28) can be set mechanically.
  4. Hydraulic regulating valve according to Claim 2, characterized in that the adjusting piston (13) is fixed on the pull rod (23) by a stressing element (22).
  5. Hydraulic regulating valve according to Claim 2, characterized in that the spring sleeve (18) can be screwed with the spring abutment (11) in an outer housing (16) relative to a position (29), which is predefined in the outer housing (16), for the highest possible regulating-spring prestress.
  6. Hydraulic regulating valve according to Claim 2, characterized in that the second stop (21) is arranged on a screw insert (20) which can be screwed into the spring sleeve.
  7. Hydraulic regulating valve according to Claim 2, characterized in that a control chamber (30) is provided in the spring sleeve (18) at the first stop (28), in which control chamber (30) the actuating piston (13) is situated, and in that the control chamber (30) is connected to a pressure connection (26) of the outer housing (16) via a channel (27) which penetrates the threaded region (17) between the spring sleeve and the outer housing.
  8. Hydraulic regulating valve according to Claim 2, characterized in that the inner space of the spring sleeve (18) which contains the holding spring (14) is connected to a return connection (25) of the outer housing (16).
  9. Hydraulic regulating valve according to Claim 2, characterized in that a 3/2-way solenoid seat valve (8) is arranged on the outer housing (16), which valve (8) can be fed with supply pressure, preferably via a supply channel which is formed in the outer housing and is connected to a pressure connection of the regulating valve (R).
  10. Electrohydraulic stressing apparatus (S), in particular for a machine tool, having a stressing cylinder (1) which is connected via a directional control valve (4) to a regulating valve (R) for the stressing pressure, which regulating valve (R) has a regulating spring (11) which is supported on a spring abutment (12), it being possible for the spring abutment (12) of the regulating spring (R) to be adjusted optionally hydraulically, in order to change the prestress of the regulating spring (11), between two mechanically fixed regulating-spring prestressing positions which are assigned to a higher and a lower regulating-spring prestress, characterized in that a 3/2-way solenoid valve (8) which is in parallel with the regulating valve (R) is provided to select the regulating-spring prestressing position, and in that the regulating valve (R) is configured in such a way and connected to the regulating valve (R) that the prestressing position which is assigned to the higher regulating-spring prestress can be set or held automatically in the regulating valve (R) in the event of a power failure.
EP06016027A 2006-08-01 2006-08-01 Hydraulic control valve and electrohydraulic clamping device Expired - Fee Related EP1884853B1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
AT06016027T ATE422255T1 (en) 2006-08-01 2006-08-01 HYDRAULIC CONTROL VALVE AND ELECTROHYDRAULIC TENSIONING DEVICE
DE502006002776T DE502006002776D1 (en) 2006-08-01 2006-08-01 Hydraulic control valve and electro-hydraulic tensioning device
EP06016027A EP1884853B1 (en) 2006-08-01 2006-08-01 Hydraulic control valve and electrohydraulic clamping device

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Publication number Priority date Publication date Assignee Title
DE3625222A1 (en) * 1986-07-25 1988-02-04 Index Werke Kg Hahn & Tessky PRESSURE REGULATOR FOR HYDRAULICALLY CONTROLLED MACHINE TOOLS
DE9310932U1 (en) * 1993-07-21 1993-09-30 Heilmeier & Weinlein Electro-hydraulic control device
DE29710127U1 (en) * 1997-06-10 1997-08-14 Heilmeier & Weinlein Electro-hydraulic clamping device
DE20208990U1 (en) * 2002-06-10 2003-10-23 Hawe Hydraulik Gmbh & Co Kg Electro-hydraulic clamping device

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DE502006002776D1 (en) 2009-03-19
EP1884853A1 (en) 2008-02-06
ATE422255T1 (en) 2009-02-15

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