DE3815968A1 - Control arrangement for a double-acting working cylinder - Google Patents

Control arrangement for a double-acting working cylinder

Info

Publication number
DE3815968A1
DE3815968A1 DE19883815968 DE3815968A DE3815968A1 DE 3815968 A1 DE3815968 A1 DE 3815968A1 DE 19883815968 DE19883815968 DE 19883815968 DE 3815968 A DE3815968 A DE 3815968A DE 3815968 A1 DE3815968 A1 DE 3815968A1
Authority
DE
Germany
Prior art keywords
pressure chamber
pressure
working cylinder
control valve
force
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.)
Withdrawn
Application number
DE19883815968
Other languages
German (de)
Inventor
Hartmut Dipl Ing Sandau
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.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Priority to DE19883815968 priority Critical patent/DE3815968A1/en
Publication of DE3815968A1 publication Critical patent/DE3815968A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/06—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle
    • B62D5/09—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle characterised by means for actuating valves
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D7/00—Steering linkage; Stub axles or their mountings
    • B62D7/06—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins
    • B62D7/14—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
    • F15B11/044—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the return line, i.e. "meter out"
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/21—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge
    • F15B2211/212—Systems with pressure sources other than pumps, e.g. with a pyrotechnical charge the pressure sources being accumulators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30505—Non-return valves, i.e. check valves
    • 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
    • F15B2211/3056—Assemblies of multiple valves
    • F15B2211/30565—Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve
    • F15B2211/3057—Assemblies of multiple valves having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve having two valves, one for each port of a double-acting output member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6306—Electronic controllers using input signals representing a pressure
    • F15B2211/6309—Electronic controllers using input signals representing a pressure the pressure being a pressure source supply pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6336—Electronic controllers using input signals representing a state of the output member, e.g. position, speed or acceleration
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/665—Methods of control using electronic components
    • F15B2211/6654—Flow rate control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—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

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Engineering & Computer Science (AREA)
  • Vehicle Body Suspensions (AREA)

Abstract

The control arrangement for a double-acting working cylinder has two control valves (19, 20) which are set against the force of springs (23, 24) via an electronic control unit (27) in such a way that fluid can correspondingly be admitted to the pressure spaces (14, 15) of the working cylinder. A piston (32, 37) to which fluid is admitted acts on each control valve (19, 20). The piston (32, 37) acts on the relevant control valve (19, 20) from the other respective pressure space against the force of a spring (33, 38). Excess pressures which act on the working cylinder (16) from outside are avoided by this arrangement. <IMAGE>

Description

Stand der TechnikState of the art

Die Erfindung geht aus von einer Steuereinrichtung für einen doppeltwirkenden Arbeitszylinder nach der Gattung des Hauptan­ spruchs. Derartig bekannte Steuereinrichtungen sind bekannt, weisen aber den Nachteil auf, daß sie für gewisse Sonderzwecke nicht aus­ reichend sind.The invention relates to a control device for a double-acting cylinder according to the type of main saying. Such known control devices are known to have but the disadvantage is that they are not made for certain special purposes are sufficient.

Vorteile der ErfindungAdvantages of the invention

Die erfindungsgemäße Steuereinrichtung mit den kennzeichnenden Merk­ malen des Hauptanspruchs hat den Vorteil, daß sie für besondere Zwecke besonders gut geeignet ist, z. B. der hydraulischen Hinter­ achslenkung eines Fahrzeugs, die nach dem sogenannten Druckabbau­ prinzip arbeitet, bei der Drucküberhöhungen durch äußere Kräfte ver­ mieden bzw. in Grenzen gehalten werden müssen.The control device according to the invention with the characteristic note Painting the main claim has the advantage that it is for special Purposes are particularly suitable, e.g. B. the hydraulic rear axle steering of a vehicle after the so-called pressure reduction principle works, in the pressure increases by external forces ver avoided or kept within limits.

Zeichnungdrawing

Ein Ausführungsbeispiel der Erfindung ist in der Zeichnung darge­ stellt und in der nachfolgenden Beschreibung näher erläutert. Die Zeichnung zeigt in schematischer Darstellung eine Steuereinrichtung für einen doppeltwirkenden Arbeitszylinder. An embodiment of the invention is shown in the drawing represents and explained in more detail in the following description. The Drawing shows a control device in a schematic representation for a double-acting cylinder.  

Beschreibung des AusführungsbeispielsDescription of the embodiment

In der Zeichnung ist mit 10 eine Druckmittelquelle bezeichnet, z. B. eine Pumpe oder ein Druckspeicher, die an eine Leitung 11 ange­ schlossen ist. Von dieser Leitung führen zwei Leitungen 12, 13 zu den beiden Druckräumen 14, 15 eines doppeltwirkenden Arbeits­ zylinders 16, dessen Kolbenstange mit 17 und der Kolben selbst mit 18 bezeichnet ist. In der Leitung 12 ist ein Steuerventil 19 ange­ ordnet, das dem Druckraum 15 zugeordnet ist, in der Leitung 16 ist ein ebensolches Steuerventil 20 angeordnet, das dem Druckraum 14 zugeordnet ist. Auf beide Steuerventile wirkt je ein Elektromagnet 21 bzw. 22 ein, und zwar entgegen der Kraft jeweils einer Feder 23, 24. Die Federn 23, 24 sind bestrebt, das Steuerventil in Durchfluß­ stellung I zu bringen, während die Elektromagnete 21, 22 das Steuer­ ventil in eine Stellung bringen, in der sie eine Druckentlastung des Druckraums 14 bzw. 15 herbeiführen. Die beiden Elektromagneten werden über elektrische Leitungen 25, 26 angesteuert, und zwar von einem elektronischen Steuergerät 27. Von der Leitung 12 zeigt von einer Stelle zwischen dem Druckraum 15 und dem Steuerventil 19 eine Steuerleitung 30 ab, die zum Druckraum 31 eines Kolbens 32 führt, der entgegen der Kraft einer sich am Steuerventilgehäuse abstützen­ den Feder 33 auf den Steuerventilschieber 20 in Entlastungsrichtung des Druckraums 14 einwirkt. Von der Leitung 13 geht von einer Stelle zwischen dem Druckraum 14 und dem Steuerventil 20 eine Leitung 35 aus, die zum Druckraum 36 eines Kolbens 37 führt. Der Kolben wirkt entgegen der Kraft einer Feder 38 ebenfalls im Entlastungssinn des Druckraums 15 auf das Steuerventil 19 ein.In the drawing, 10 denotes a pressure medium source, for. B. a pump or a pressure accumulator, which is connected to a line 11 . From this line, two lines 12 , 13 lead to the two pressure chambers 14 , 15 of a double-acting working cylinder 16 , the piston rod with 17 and the piston itself is designated 18 . In the line 12 , a control valve 19 is arranged, which is assigned to the pressure chamber 15 , in the line 16 , the same control valve 20 is arranged, which is assigned to the pressure chamber 14 . An electromagnet 21 or 22 acts on each of the two control valves, against the force of a spring 23 , 24 . The springs 23 , 24 endeavor to bring the control valve into the flow position I, while the electromagnets 21 , 22 bring the control valve into a position in which they bring about pressure relief of the pressure chamber 14 or 15 . The two electromagnets are controlled via electrical lines 25 , 26 , specifically by an electronic control unit 27 . From the line 12 , a control line 30 points from a point between the pressure chamber 15 and the control valve 19 , which leads to the pressure chamber 31 of a piston 32 which, against the force of a spring 33 supported on the control valve housing, on the control valve spool 20 in the relief direction of the pressure chamber 14 acts. A line 35 leads from the line 13 from a point between the pressure chamber 14 and the control valve 20 and leads to the pressure chamber 36 of a piston 37 . The piston also acts against the force of a spring 38 in the relief direction of the pressure chamber 15 on the control valve 19 .

An die Kolbenstange 17 ist noch in bekannter Weise ein Weggeber 39 angeschlossen, der über eine elektrische Leitung 40 dem Steuergerät 27 die Position der Kolbenstange 17 anzeigt. In jeder der beiden Leitungen 12, 13 ist ein Ruckschlagventil 41, 42 angeordnet, die in Richtung von der Leitung 11 zu den Druckräumen 14, 15 des Arbeits­ zylinders 16 hin öffenbar sind. Die beiden Steuerventile 19, 20 sind an eine Entlastungsleitung angeschlossen, die zu einem Behälter führt. A displacement sensor 39 is also connected to the piston rod 17 in a known manner and indicates the position of the piston rod 17 to the control unit 27 via an electrical line 40 . In each of the two lines 12 , 13 a check valve 41 , 42 is arranged, which can be opened in the direction from line 11 to the pressure chambers 14 , 15 of the working cylinder 16 . The two control valves 19 , 20 are connected to a relief line that leads to a container.

Soll der Arbeitszylinder 16 betätigt werden, z. B. daß er nach links ausfährt, so wird das Steuerventil 19 in seine Durchflußrichtung I geschaltet, das Steuerventil 20 in seine Durchflußstellung II. Druckmittel gelangt nun von der Leitung 11 über die Leitung 12 in den Druckraum 15, vom Druckraum 14 fließt Druckmittel über das Steuerventil 20 zum Behälter 44.If the working cylinder 16 are actuated, for. B. that it extends to the left, the control valve 19 is switched in its flow direction I, the control valve 20 in its flow position II. Pressure medium now passes from line 11 via line 12 into pressure chamber 15 , from pressure chamber 14 , pressure medium flows via Control valve 20 to container 44 .

Befinden sich beide Steuerventile in der Schaltstellung I, so sind beide Druckräume 14, 15 gleichermaßen beaufschlagt, d. h. der Arbeitszylinder 16 ist hydraulisch verriegelt. Wirkt von außen her auf die Kolbenstange 17 eine Kraft z. B. in Richtung des Pfeils F, so steigt der Druck im Druckraum 15 an. Dieser Druck pflanzt sich über die Steuerleitung 30 in den Druckraum 31 des Kolbens 32 fort. Liegt dieser Druck über dem Systemdruck, d. h. der Druck in den Leitungen 11, 12 und 13, so überwiegt die Kraft des Kolbens 32 die Kraft der Feder 33, wodurch das Steuerventil 20 in seine Schalt­ stellung II gelangt. Nun kann Druckmittel aus dem Druckraum 14 zum Behälter 44 abströmen. Dadurch fällt der Druck im Druckraum 14, wodurch die Kraft auf den Kolben 18 vom Druckraum 15 her sich solange vergrößert, bis die auf die Kolbenstangen bzw. den Kolben 18 wirkende Kraft F auf die Kolbenstange kompensiert ist. Wirkt die Kraft F in der entgegengesetzten Richtung, so geschieht beim Steuer­ ventil 19 dasselbe. Wenn die Kraft F kompensiert ist, stellen die Federn 19, 20 ihre zugehörigen Steuerventile wieder in die zuvor eingenommene Schaltstellung, d. h. die Schaltstellung I. Auf die oben beschriebene Weise wird der maximale Druck in einem der beiden Druckräume vermindert. Ein Drucküberhöhung durch äußere Kräfte wird somit vermieden bzw. in Grenzen gehalten.If both control valves are in the switching position I, both pressure chambers 14 , 15 are acted upon equally, ie the working cylinder 16 is hydraulically locked. A force acts on the piston rod 17 from the outside z. B. in the direction of arrow F , the pressure in the pressure chamber 15 increases . This pressure propagates through the control line 30 into the pressure chamber 31 of the piston 32 . If this pressure is above the system pressure, ie the pressure in the lines 11 , 12 and 13 , the force of the piston 32 outweighs the force of the spring 33 , as a result of which the control valve 20 reaches its switching position II. Now pressure medium can flow out of the pressure chamber 14 to the container 44 . As a result, the pressure in the pressure chamber 14 drops, as a result of which the force on the piston 18 from the pressure chamber 15 increases until the force F acting on the piston rods or the piston 18 on the piston rod is compensated. If the force F acts in the opposite direction, the same thing happens with the control valve 19 . When the force F is compensated, the springs 19 , 20 return their associated control valves to the switching position previously assumed, ie switching position I. In the manner described above, the maximum pressure in one of the two pressure spaces is reduced. A pressure increase by external forces is thus avoided or kept within limits.

Claims (3)

1. Steuereinrichtung für einen doppeltwirkenden Arbeitszylinder (16), dessen beiden Druckräumen (14, 15) jeweils ein Steuerventil (19, 20) zugeordnet ist, die durch je einen Elektromagneten (21, 22) entgegen der Kraft einer Feder (23, 24) in Entlastungsstellung des betreffenden Druckraums verstellbar sind und durch die Federn in eine Stellung, in welcher der betreffende Druckraum mit Systemdruck beaufschlagt ist, dadurch gekennzeichnet, daß jedem Steuerventil (19, 20) ein auf dieses in Richtung Entlastung des Druckraums ein­ wirkender, vom Druck im jeweils anderen Druckraum beaufschlagter Kolbens (32, 37) zugeordnet ist, auf den in entgegengesetzter Rich­ tung die Kraft einer Feder (33, 38) einwirkt.1. Control device for a double-acting working cylinder ( 16 ), the two pressure chambers ( 14 , 15 ) of which a control valve ( 19 , 20 ) is assigned, which is controlled by an electromagnet ( 21 , 22 ) against the force of a spring ( 23 , 24 ) are adjustable in the relief position of the pressure chamber in question and by the springs in a position in which the pressure chamber in question is acted upon by system pressure, characterized in that each control valve ( 19 , 20 ) acting on the pressure chamber in the direction of relieving the pressure chamber each other pressure chamber acted upon piston ( 32 , 37 ) is assigned, acting on the force of a spring ( 33 , 38 ) in the opposite direction Rich. 2. Einrichtung nach Anspruch 1, dadurch gekennzeichnet, daß die Steuerventile als 3/2-Wegeventile ausgebildet sind.2. Device according to claim 1, characterized in that the Control valves are designed as 3/2-way valves. 3. Einrichtung nach Anspruch 1 und/oder 2, dadurch gekennzeichnet, daß die Steuerventile durch ein elektronisches Steuergerät (27) ein­ gestellt werden, das auch über einen Weggeber (39) die Position der Kolbenstange (17) erfaßt.3. Device according to claim 1 and / or 2, characterized in that the control valves are set by an electronic control unit ( 27 ), which also detects the position of the piston rod ( 17 ) via a displacement sensor ( 39 ).
DE19883815968 1988-05-10 1988-05-10 Control arrangement for a double-acting working cylinder Withdrawn DE3815968A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE19883815968 DE3815968A1 (en) 1988-05-10 1988-05-10 Control arrangement for a double-acting working cylinder

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19883815968 DE3815968A1 (en) 1988-05-10 1988-05-10 Control arrangement for a double-acting working cylinder

Publications (1)

Publication Number Publication Date
DE3815968A1 true DE3815968A1 (en) 1989-11-23

Family

ID=6354082

Family Applications (1)

Application Number Title Priority Date Filing Date
DE19883815968 Withdrawn DE3815968A1 (en) 1988-05-10 1988-05-10 Control arrangement for a double-acting working cylinder

Country Status (1)

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DE (1) DE3815968A1 (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4118822A1 (en) * 1991-06-07 1992-12-10 Rexroth Mannesmann Gmbh Control circuit for vehicle hydraulic suspension - has separate solenoid valves for flow control and with valve action varied by control current
DE19707722A1 (en) * 1996-11-11 1998-05-14 Rexroth Mannesmann Gmbh Valve arrangement and method for controlling such a valve arrangement
WO1999037929A1 (en) * 1998-01-23 1999-07-29 Mannesmann Rexroth Ag Hydraulic system for operating a reversible hydraulic consumer
US6196247B1 (en) 1996-11-11 2001-03-06 Mannesmann Rexroth Ag Valve assembly and method for actuation of such a valve assembly
NL1031722C2 (en) * 2006-04-28 2007-10-30 Actuant Corp Hydraulic operating device for a closing assembly for an opening in a vehicle body.

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4118822A1 (en) * 1991-06-07 1992-12-10 Rexroth Mannesmann Gmbh Control circuit for vehicle hydraulic suspension - has separate solenoid valves for flow control and with valve action varied by control current
DE19707722A1 (en) * 1996-11-11 1998-05-14 Rexroth Mannesmann Gmbh Valve arrangement and method for controlling such a valve arrangement
US6196247B1 (en) 1996-11-11 2001-03-06 Mannesmann Rexroth Ag Valve assembly and method for actuation of such a valve assembly
WO1999037929A1 (en) * 1998-01-23 1999-07-29 Mannesmann Rexroth Ag Hydraulic system for operating a reversible hydraulic consumer
NL1031722C2 (en) * 2006-04-28 2007-10-30 Actuant Corp Hydraulic operating device for a closing assembly for an opening in a vehicle body.

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