EP0279315B1 - Hydraulic control device - Google Patents

Hydraulic control device Download PDF

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Publication number
EP0279315B1
EP0279315B1 EP88101810A EP88101810A EP0279315B1 EP 0279315 B1 EP0279315 B1 EP 0279315B1 EP 88101810 A EP88101810 A EP 88101810A EP 88101810 A EP88101810 A EP 88101810A EP 0279315 B1 EP0279315 B1 EP 0279315B1
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EP
European Patent Office
Prior art keywords
control
valve
piston
control device
pressure
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP88101810A
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German (de)
French (fr)
Other versions
EP0279315A3 (en
EP0279315A2 (en
Inventor
Martin Dipl.-Ing.(Eth) Heusser
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Heilmeier and Weinlein Fabrik fuer Oel Hydraulik GmbH and Co KG
Original Assignee
Heilmeier and Weinlein Fabrik fuer Oel Hydraulik GmbH and Co KG
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Application filed by Heilmeier and Weinlein Fabrik fuer Oel Hydraulik GmbH and Co KG filed Critical Heilmeier and Weinlein Fabrik fuer Oel Hydraulik GmbH and Co KG
Priority to AT88101810T priority Critical patent/ATE68243T1/en
Publication of EP0279315A2 publication Critical patent/EP0279315A2/en
Publication of EP0279315A3 publication Critical patent/EP0279315A3/en
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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
    • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
    • F15B11/05—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed specially adapted to maintain constant speed, e.g. pressure-compensated, load-responsive
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40515—Flow control characterised by the type of flow control means or valve with variable throttles or orifices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40553—Flow control characterised by the type of flow control means or valve with pressure compensating valves
    • F15B2211/40569—Flow control characterised by the type of flow control means or valve with pressure compensating valves the pressure compensating valve arranged downstream of the flow control means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/41563—Flow control characterised by the connections of the flow control means in the circuit being connected to a pressure source and a 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
    • F15B2211/40—Flow control
    • F15B2211/42—Flow control characterised by the type of actuation
    • F15B2211/426—Flow 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
    • F15B2211/42—Flow control characterised by the type of actuation
    • F15B2211/428—Flow control characterised by the type of actuation actuated by fluid pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/46—Control of flow in the return line, i.e. meter-out control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/465—Flow control with pressure compensation
    • 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
    • F15B2211/47—Flow control in one direction only
    • 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
    • F15B2211/7052—Single-acting output members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/80—Other types of control related to particular problems or conditions
    • F15B2211/86—Control during or prevention of abnormal conditions
    • F15B2211/8606—Control during or prevention of abnormal conditions the abnormal condition being a shock

Definitions

  • the invention relates to a hydraulic control device in the preamble of claim 1.
  • control piston which is held in the blocking position by the load pressure in the blocking position for holding the load pressure in the control chamber, requires an exact fit and a large sealing length as well as a large positive overlap in order to also keep the load pressure downstream of the measuring orifice without leakage.
  • the pressure compensator has a directional function in the zero position because the control chamber, in which the other piston end is located, is relieved of pressure by additional valve devices.
  • the invention has for its object to provide a hydraulic control device of the type mentioned, in which a switching jerk is reliably avoided with little technical effort.
  • the load pressure in the zero position of the control device is taken up on the one hand by the locking member and kept away from the pressure compensator and on the other hand by the poppet valve in the control chamber, which seals perfectly in the holding position of the control piston even with conventional fits and a short guide length of the control piston.
  • the control orifice no exaggerated positive overlap is necessary, if at all, because the load pressure is not there.
  • the result is a compact, simple construction of the pressure compensator with a suitably smooth-running control piston with a short control stroke.
  • the additional effort for the seat valve of the control chamber is negligible.
  • a conventional orifice plate construction can be used because the load pressure in the zero position is received by the seat valves in the drain line and in the control chamber and the control piston maintains its shut-off position without leakage.
  • valve seat valve between the control piston end and the valve seat.
  • the given design requirements of the pressure compensator are used to form the seat valve between the control piston end and the valve seat.
  • it means no significant effort to design the control piston end with the conical thickening and in the mouth area of the housing bore in the Control chamber to provide a valve seat.
  • the valve seat is formed by an insert, for example a hardened bushing with a tapered end that extends over the entire length of the control piston, and the conical thickening, if it is not formed in one piece with the control piston, is attached to the control piston. Pressure medium cannot leak from the control chamber to the housing bore in the zero position.
  • the embodiment of claim 5 is also important because the two-position switch valve ensures that the flow resistance of the poppet valve does not enter the control loop, i.e. that the pressure compensator with a small pressure difference can be designed in a sensitive and appealing manner, although the seat valve, which is expediently of a small construction, has a pressure difference which can be a multiple of the pressure difference of the pressure compensator.
  • the changeover valve leads the pressure medium from the control chamber in which the load pressure is maintained, bypassing the seat valve to the other control chamber as soon as it is switched over.
  • the other control line that bypasses the seat valve also serves this purpose. Without the changeover valve, for example, the control spring of the pressure compensator would have to be designed more strongly.
  • the embodiment according to claim 6 is also expedient because the seat valve automatically assumes its shut-off position under the action of the spring force when the control device is brought into the zero position.
  • a sensitive response and easy handling are achieved in the embodiment according to claim 7, wherein a modern small seat valve is inexpensive and manages with a small and inexpensive magnet.
  • the feature of claim 8 is also advantageous because the changeover valve automatically assumes its first passage position under the action of the spring force, in which the pressure-transmitting connection from the control chamber to the side of the seat valve facing away from the measuring orifice is open and the load pressure is kept away from the measuring orifice and directly is at the end of the control piston and holds the control piston in its stop position.
  • the idea of claim 10 is also advantageous because the coupling of the adjusting devices ensures that the shut-off element or seat valve and the changeover valve each change their positions simultaneously when the control device is switched over.
  • Is a changeover valve provided this is when using the pressure compensator for control in both directions together with the poppet valve in a position in which there is a pressure-transmitting connection from the side facing the poppet valve to the control chamber, so that the control piston at both piston ends of the pressures upstream and is acted upon downstream of the orifice plate and regulates the pressure drop set in each case on the orifice plate. If, on the other hand, a separate current regulator is provided for the control when the supply line is loaded, the pressure compensator remains in the shut-off position.
  • At least one further hydraulic motor is supplied with pressure medium from the supply line, the same measuring orifice and pressure compensator being used for the movement control of this further hydraulic motor as for the first hydraulic motor.
  • the non-controlled hydraulic motor is separated from the supply line by its seat valve.
  • the changeover valve nevertheless ensures that the control piston of the pressure compensator is acted upon at both piston ends by the pressures prevailing upstream and downstream of the measuring orifice and that the pressure difference set on the measuring orifice is independent of the load pressure or supply pressure fluctuations.
  • Additional loads can also be connected to the supply line, each of which can be controlled individually via the measuring orifice and the pressure compensator. Only the load pressure of the most heavily loaded hydraulic motor is transmitted to the control chamber, or it is ensured that those that have lower load pressures are shut off in the case of load pressure control lines for each hydraulic motor.
  • FIG. 1 shows a hydraulic control circuit with a hydraulic control device 1 for a hydraulic motor 2 which can be acted upon on one side against a load.
  • a hydraulic control device 1 for a hydraulic motor 2 which can be acted upon on one side against a load.
  • This is, for example, a lifting control device for the lifting piston of a forklift or a tail lift.
  • the hydraulic motor 2 is a cylinder 3, in which a piston 4 under a load 5, e.g. the weight of the lifting fork bracket of a forklift truck is slidable or hydraulically lockable.
  • a pressure source 6 e.g. a switchable hydraulic pump, supply line 7 connected via a check valve 8.
  • the supply line 7 crosses a drain line 32 from the cylinder 3 to a tank 37.
  • a measuring orifice 9 with an adjustable orifice member 10 is arranged, which is a shut-off element A which can be brought into a load-holding shut-off position.
  • An actuating actuator 11 is used for adjustment, in the present case an actuating magnet or proportional magnet.
  • a housing 13 of a pressure compensator 12 Downstream of the orifice 9, a housing 13 of a pressure compensator 12 is inserted into the drain line 32, which contains a control orifice 14, which regulates the pressure difference set on the orifice 9 and thus the speed of the piston 4 in a conventional manner.
  • An annular chamber 15 with a control edge 16 is provided in a housing bore 29.
  • a control piston 17, which is displaceably guided in the housing bore 29, has two piston parts 22 and 21 connected to one another via a piston rod 20 and a recess 19.
  • One side of the piston part 21 forms a control edge 18, which cooperates with the control edge 16 like an aperture when the control piston 17 performs its working cycle executes.
  • the left piston end 23 of the control piston 17 in FIG. 1 lies in a control chamber 30 at the left end of the housing bore 20.
  • the control chamber 30 contains a control spring 35 and is connected via a channel 34 to a channel 33 connected to the discharge line 32 downstream of the orifice plate 9 middle part of the housing bore 29 in connection.
  • the channel 33 could also be omitted if the piston end 23 forms the control edge 18 at the same time. Then pressure medium would flow directly out of the control chamber 30 via the control orifice 14.
  • the right piston end 24 of the control piston 17 is located in a control chamber 31 at the right end of the housing bore 29, the inside diameter of which is larger than the inside diameter of the housing bore 29
  • Control chamber 31 is connected via a channel 39 to a control line 40 in which a throttle 41 is arranged.
  • the control line 40 is connected to the drain line 32 between the measuring orifice 9 and the hydraulic motor 2 and leads the load pressure prevailing on the left side of the piston 4 into the control chamber 31.
  • the right piston end 24 is designed as a closing element 25 with a conical thickening 26.
  • a valve seat 27 is assigned to the closing element 25 in the mouth region of the housing bore 29 into the control chamber 31, which valve seat is attached to an insert 28 in the housing 13 in the present case.
  • the insert 28 could also be a continuous hardened sleeve with a ground valve seat.
  • a channel 36 leads from the annular chamber 15 to a tank line 38.
  • the control device 1 according to FIG. 1 is in the zero position.
  • the pressure source 6 is switched off.
  • the pressure caused by the load 5 on the left side of the piston 4 is from the check valve 8, further from the blocking member A, which is in the load-holding shut-off position, i.e. the orifice 9 and finally held by the closing element 25 which cooperates with the valve seat 27 in the manner of a seat valve.
  • the pressure medium downstream of the measuring orifice 9 is relaxed via the closed control orifice 14 (leakage losses caused by the design). As a result, the control piston 17 can no longer give up its shut-off position.
  • the pressure source 6 is activated. Unless a separate control device is provided for this direction of movement, for example between pump 6 and check valve 7, the measuring orifice 9 adjusted by the magnet 11 to an open position, which corresponds to the desired speed of movement of the piston 4. It loses its function of the locking member A.
  • the control chamber 30 is pressurized until the control piston 17 moves to the right and leaves enough pressure medium via the control orifice 16, 18 that the piston 4 only moves to the right at the set speed, independently on the size or changes in the load 5.
  • a switching jerk is avoided because the check valve 8 only opens when at least the same pressure is built up in the supply line 7 as that prevails in the control chamber 31, and because pressure medium for adjustment of the control piston 17 comes from the pressure source 6.
  • the pressure source 6 is not activated. Rather, the orifice 9 is adjusted to a position which corresponds to the desired speed of movement of the piston 4.
  • the measuring orifice 9 thus gives up its function as a blocking element A.
  • Pressure medium under the load pressure is shifted from the control chamber 31 via the control line 40, the channel 33 and the channel 34 into the control chamber 30; the control panel 14 opens. Since no appreciable positive overlap between the control edges 18, 16 is needed because the load pressure was applied to the blocking element A, no noticeable volume is required for opening the control orifice 14. Since the control spring 35 is also effective, the control piston 17 shifts to the right, the volume which is displaced from the control chamber 31 by the displacement of the control piston 17 to the right being fed to the control chamber 30. For this reason, there is no shift jerk.
  • the hydraulic motor 2 is assigned a seat valve 42 upstream of the metering orifice 9 in the embodiment of FIG the force of a spring 43 assumes its shut-off position automatically and by an actuator 44, for example a switching magnet, is adjustable in a through position.
  • the seat valve 42 forms the blocking member A ⁇ in the shut-off position.
  • the control line 40 is connected to the drain line 32 between the seat valve 42 and the hydraulic motor 2. In the zero position of the control device 1 ⁇ , whose pressure compensator 12 corresponds to that of FIG.
  • the load pressure of the hydraulic motor 2 is thus taken up by the seat valve 42 and by the closing element 25 on the valve seat 27.
  • the measuring orifice 9 can therefore easily remain open in the zero position. This also means that e.g. for a tail lift control with constant speed of movement of the hydraulic motor 2, a fixed measuring orifice 9 can be used.
  • the pressure source 6 is first activated in the zero position and the seat valve 42 is switched to its open position. Then, depending on the setting of the orifice 9, the piston of the hydraulic motor 2 is moved against the load. The pressure medium from the control chamber 31 is displaced under the load pressure with the volume into the control chamber 30 which the control piston 17 displaces. A shift jerk does not occur. If a separate control device is used for this direction of movement (for example between the pressure source 6 and the check valve 7), then the orifice 9 in the Locked position held. The pressure compensator 12 is not working.
  • the same pressure compensator 12 is used again as in the embodiment of FIGS. 1 and 2.
  • the measuring orifice 9 can be adjustable or fixed.
  • a two-position switch valve 45 is provided in the control line 40 in the control device 1 ⁇ according to FIG. 3, which is connected to the drain line 32 between the seat valve 42 and the hydraulic motor 2 and consequently always carries the load pressure.
  • the control line 40 has two parts 40a and 40b, between which the changeover valve 45 is located.
  • a second control line 48 is provided, which is connected to the drain line 32 between the measuring orifice 9 and the seat valve 42 and also leads to the changeover valve 45.
  • the changeover valve 45 is brought into a first through position by a spring 46, in which the two parts 40a and 40b of the control line are connected to one another and the second control line 48 is separated.
  • An actuating device 47 for example a switching magnet, is provided on the changeover valve, with which the changeover valve 45 is converted into a second one Passable position can be brought in which a pressure-transmitting connection between the part 40b of the control line 40 and the second control line 48 is established, while the first part 40a is separated from the part 40b.
  • the actuating devices of the seat valve 42 and the changeover valve 45 can optionally be connected to one another by a coupling 49, so that they are always actuated in the same direction.
  • the pressure source 6 is first activated and the measuring orifice 9 is set for the desired movement speed.
  • the control piston is in its shut-off position, in which it is held by the load pressure from the open control line 40.
  • the seat valve 42 and, at the same time, the switching valve 45 are switched via the coupling 49, so that the seat valve 42 assumes its passage position and the switching valve 45 its second passage position, in which the part 40b of the control line 40 is connected to the second control line 48 and the part 40a of the control line 40 are separated.
  • the control piston is moved to the right, so that the control orifice begins to open gradually.
  • the volume that is in this adjustment of the control piston in the Control chamber 31 is displaced, is supplied via part 40b, the changeover valve 45, the control line 48 and the drain line 32 to the control chamber 30, so that a switching jolt is reliably avoided. If a separate control device (for example a current regulator) is provided for this direction of movement, the pressure compensator 12 does not work. The respective load pressure is kept in the zero position.
  • a separate control device for example a current regulator
  • the poppet valve 42 To move the hydraulic motor 2 under the load - starting from the zero position - the poppet valve 42 is moved into the through position and the changeover valve 45 into its second through position so that the control chambers 30, 31 are acted upon with the pressures upstream and downstream of the orifice plate 9 and the Flow resistance of the seat valve 42 is not included in the control behavior.
  • the control orifice 14 is opened in accordance with the setting of the orifice 9.
  • the pressure medium volume corresponding to the movement of the control piston 17 is displaced from the control chamber 31 into the control chamber 30. There is no switching jerk.
  • the seat valve 42 is switched over together with the changeover valve 45.
  • the load pressure is again held by the seat valve 42 and the seat valve between the closing element 25 and the valve seat 27.
  • the second control line 48 is disconnected.
  • the control chamber 30 is relieved via the control panel 14.
  • the control device 1 ⁇ can be expanded by adding at least one further hydraulic motor 2 ⁇ to a control device 1 ′′ ', with which it is possible to use several hydraulic motors 2, 2 ⁇ with the common measuring orifice 9 and the common pressure compensator 12 and the common switch valve 45 to control independent of the load pressure.
  • the further hydraulic motor 2 ⁇ is connected via its drain line 32 ⁇ to the supply line 7.
  • a seat valve 42 ⁇ corresponding to the seat valve 32 is arranged, which holds the load pressure of the hydraulic motor 2 ⁇ in the shut-off position and allows the pressure medium to be released or supplied in its through position.
  • a control line 40a ⁇ corresponding to part 40a of control line 40 can lead from drain line 32 ⁇ between seat valve 42 ⁇ and hydraulic motor 2 ⁇ to control line part 40a and thus to changeover valve 45.
  • Check valves 51, 52 are expediently provided in the control line parts 40a and 40a ⁇ .
  • Interfaces 50 indicated by dash-dotted lines show where and how the other hydraulic motor (s) 2 ⁇ are connected. If the hydraulic motor 2 has the highest load pressure, the control line part 40a ⁇ can be omitted.
  • the hydraulic motors 2, 2 ⁇ are expediently controlled individually, i.e. as soon as one hydraulic motor moves, the other remains in its load-holding position.
  • control device 1, 1 ⁇ , 1 is that when the control device is switched from the zero position to a position for moving the hydraulic motor under load, there is no switching jerk because this occurs between the closing element 25 and the valve seat 27 formed seat valve in the pressure compensator works practically leak-free, so that no pressure medium is lost even over longer downtimes, but exactly at the beginning of the movement of the pressure medium under load pressure in the control chamber with the seat valve the volume is removed and transferred to the other control chamber, which is required to open the control panel without the undesirable switching jerk.
  • This volume is, so to speak, held ready for retrieval in a pressure accumulator integrated in the control device, without the pressure source having to contribute to this.

Abstract

In hydraulic control devices comprising a two-way flow regulator in a reservoir return passage, in which the flow regulator comprises a metering restriction and a pressure equalizer including a control piston with the piston ends disposed in control chambers and subjected to the action of control pressures, the actuation of a single-acting hydraulic motor under load often results in an unavoidable switching shock, because the displacement of the control piston involves the consumption of a certain volume of the pressure fluid. In order to eliminate the switching shock with a simple construction, the end of the control piston subjected to the action of the load pressure is formed as a closure element cooperating with a valve seat in the manner of a poppet valve for holding the load pressure.

Description

Die Erfindung betrifft eine hydraulische Steuervorrichtung der im Oberbegriff des Patentanspruchs 1.The invention relates to a hydraulic control device in the preamble of claim 1.

Eine solche Steuervorrichtung wird bereits in der DE-A-3536 218 mit älterem Zeitrang vorgeschlagen. Der zum Halten des Lastdrucks in der Steuerkammer durch den Lastdruck in der Sperrstellung gehaltene Regelkolben benötigt zur Abdichtung eine genaue Passung und eine große Abdichtlänge sowie eine große positive Überdeckung, um auch den Lastdruck stromab der Meßblende ohne Leckverlust zu halten. Die Druckwaage hat in der Nullstellung eine Wegefunktion, weil die Steuerkammer, in der das andere Kolbenende liegt, durch zusätzliche Ventileinrichtungen druckentlastet wird. Obwohl bei dieser vorgeschlagenen Steuervorrichtung der Schaltruck weitgehend eliminiert wird, ist der steuerungstechnische und fertigungstechnische Aufwand hierfür unvertretbar groß. In der Praxis zeigt sich jedoch, daß zwar der Schaltruck beim Umschalten nicht mehr in der Stärke auftritt, wie dies bei älteren Steuervorrichtungen, z.B. gemäß der DE-A-3233 046 stets der Fall war, daß er unter ungünstigen Verhältnissen und aufgrund der großen positiven Überdeckung des Regelkolbens immer noch spürbar ist, u.a. auch weil die Druckwaage konstruktionsbedingt den Lastdruck nicht halten kann.Such a control device is already proposed in DE-A-3536 218 with an older seniority. The control piston, which is held in the blocking position by the load pressure in the blocking position for holding the load pressure in the control chamber, requires an exact fit and a large sealing length as well as a large positive overlap in order to also keep the load pressure downstream of the measuring orifice without leakage. The pressure compensator has a directional function in the zero position because the control chamber, in which the other piston end is located, is relieved of pressure by additional valve devices. Although the switching jerk is largely eliminated in the case of this proposed control device, the expenditure on control technology and production technology is unacceptably high. In practice, however, it turns out that the switching jerk no longer occurs when switching, as was the case with older control devices, for example according to DE-A-3233 046, that it was under unfavorable conditions and because of the large positive Coverage of the control piston is still noticeable, partly because the pressure compensator cannot maintain the load pressure due to the design.

Der Erfindung liegt die Aufgabe zugrunde, eine hydraulische Steuervorrichtung der eingangs genannten Art zu schaffen, bei der mit technisch geringem Aufwand ein Schaltruck zuverlässig vermieden wird.The invention has for its object to provide a hydraulic control device of the type mentioned, in which a switching jerk is reliably avoided with little technical effort.

Die gestellte Aufgabe wird erfindungsgemäß durch die im kennzeichnenden Teil des Patentanspruchs 1 angegebenen Merkmale gelöst.The object is achieved according to the invention by the features specified in the characterizing part of patent claim 1.

Bei dieser Ausbildung wird der Lastdruck in der Nullstellung der Steuervorrichtung einerseits vom Sperrglied aufgenommen und von der Druckwaage ferngehalten und andererseits vom Sitzventil in der Steuerkammer, das in der Haltestellung des Regelkolbens auch bei üblichen Passungen und kurzer Führungslänge des Regelkolbens einwandfrei abdichtet. Bei der Regelblende ist - wenn überhaupt - keine übertriebene positive Überdeckung notwendig, weil der Lastdruck dort nicht ansteht. Es resultiert daraus ein kompakter einfacher Aufbau der Druckwaage bei zweckmäßig leichtgängigem Regelkolben mit kurzem Regelhub. Der Mehraufwand für das Sitzventil der Steuerkammer ist vernachlässigbar.In this embodiment, the load pressure in the zero position of the control device is taken up on the one hand by the locking member and kept away from the pressure compensator and on the other hand by the poppet valve in the control chamber, which seals perfectly in the holding position of the control piston even with conventional fits and a short guide length of the control piston. With the control orifice, no exaggerated positive overlap is necessary, if at all, because the load pressure is not there. The result is a compact, simple construction of the pressure compensator with a suitably smooth-running control piston with a short control stroke. The additional effort for the seat valve of the control chamber is negligible.

Bei dieser Lösung wird erreicht, daß bei Aufgabe der Nullstellung, z.B. zum Senken eines Hubzylinders, zum Öffnen der Regelblende ein sehr kleiner Hub des Regelkolbens ausreicht, bei dem auch das bis dahin lasthaltende Sitzventil öffnet und auf das weitere Regelspiel des Regelkolbens keinen Einfluß mehr nimmt. Der Schaltruck bleibt auch deswegen aus, weil der Regelkolben in der Nullstellung in der Absperrstellung bleibt, so daß kein Volumen gebraucht wird, um ihn erst (z.B. über einen 10mm-Hub) in die Absperrstellung zu drücken.With this solution it is achieved that when the zeroing, e.g. for lowering a lifting cylinder, for opening the control orifice, a very small stroke of the control piston is sufficient, in which the seat valve that has been holding the load opens up to that point and no longer influences the further control play of the control piston. The switching jerk also does not occur because the control piston remains in the shut-off position in the zero position, so that no volume is needed to push it into the shut-off position (e.g. via a 10 mm stroke).

Es ist zwar aus einem Prospekt RD 09 506 der Firma Rexroth AG, bekannt, das Anfahrverhalten in einer Steuervorrichtung mit einer Druckwaage dadurch zu verbessern, daß ein Regelkolbenende unmittelbar durch den Pumpendruck beaufschlagt und damit die Regelblende von außen in der Sperrstellung gehalten wird. Jedoch arbeitet der Regelkolben mit der Gehäusebohrung nur als Schieber zusammen und ist ferner die Steuervorrichtung so nur für einen doppelseitig beaufschlagbaren Hydromotor brauchbar, was bedeutet, daß für jede Bewegungsrichtung des Hydromotors und auch in der Nullstellung die Pumpe eingeschaltet sein muß, d.h. insbesondere auch für das Senken unter Last.It is from a brochure RD 09 506 from the company Rexroth AG, known to improve the starting behavior in a control device with a pressure compensator in that a control piston end is acted upon directly by the pump pressure and thus the control orifice is held from the outside in the locked position. However, the control piston cooperates with the housing bore only as a slide and the control device is also only usable for a double-acting hydraulic motor, which means that the pump must be switched on for every direction of movement of the hydraulic motor and also in the zero position, ie especially for that Lowering under load.

Eine zweckmäßige Ausführungsform geht aus Anspruch 2 hervor. Damit der Lastdruck von der leckagebehafteten Regelblende der Druckwaage ferngehalten wird, braucht nur die Meßblende in ihrer Absperrstellung dicht zu sein, z.B. indem sie mit einer Sitz-Ventil-Funktion versehen wird. Die Steuervorrichtung besteht nur aus wenigen Komponenten.An expedient embodiment emerges from claim 2. In order for the load pressure to be kept away from the leakage regulating orifice of the pressure compensator, only the measuring orifice needs to be tight in its shut-off position, e.g. by providing it with a seat valve function. The control device consists of only a few components.

Bei der Ausführungsform gemäß Anspruch 3 kann eine übliche Meßblendenkonstruktion benutzt werden, weil der Lastdruck in der Nullstellung von den Sitzventilen in der Ablaßleitung und in der Steuerkammer aufgenommen wird und der Regelkolben leckverlustfrei seine Absperrstellung beibehält.In the embodiment according to claim 3, a conventional orifice plate construction can be used because the load pressure in the zero position is received by the seat valves in the drain line and in the control chamber and the control piston maintains its shut-off position without leakage.

Eine weitere zweckmäßige Ausführungsform der Erfindung geht aus Anspruch 4 hervor. Hierbei werden die gegebenen konstruktiven Voraussetzungen der Druckwaage zur Ausbildung des Sitzventils zwischen dem Regelkolbenende und dem Ventilsitz benutzt. Es bedeutet fertigungstechnisch keinen nennenswerten Aufwand, das Regelkolbenende mit der kegeligen Verdickung auszubilden und im Mündungsbereich der Gehäusebohrung in der Steuerkammer einen Ventilsitz vorzusehen. Gegebenenfalls wird der Ventilsitz durch einen Einsatz, z.B. eine über die ganze Regelkolbenlänge durchgehende, gehärtete Büchse mit kegelig angeschliffenem Ende, gebildet, und wird die kegelige Verdickung, falls sie nicht einstückig mit dem Regelkolben ausgebildet wird, am Regelkolben angesetzt. Druckmittel kann in der Nullstellung aus der Steuerkammer nicht zur Gehäusebohrung durchlecken.A further expedient embodiment of the invention can be found in claim 4. Here, the given design requirements of the pressure compensator are used to form the seat valve between the control piston end and the valve seat. In terms of production technology, it means no significant effort to design the control piston end with the conical thickening and in the mouth area of the housing bore in the Control chamber to provide a valve seat. If necessary, the valve seat is formed by an insert, for example a hardened bushing with a tapered end that extends over the entire length of the control piston, and the conical thickening, if it is not formed in one piece with the control piston, is attached to the control piston. Pressure medium cannot leak from the control chamber to the housing bore in the zero position.

Wichtig ist ferner die Ausführungsform von Anspruch 5, weil mit dem Zweistellungs-Umschaltventil erreicht wird, daß der Durchströmwiderstand des Sitzventils nicht in den Regelkreis eingeht, d.h. daß die Druckwaage mit einer kleinen Druckdifferenz feinfühlig ansprechend ausgelegt werden kann, obwohl das Sitzventil, das zweckmäßigerweise nur klein bauend ist, eine Druckdifferenz besitzt, die ein Mehrfaches der Druckdifferenz der Druckwaage sein kann. Das Umschaltventil führt nämlich das Druckmittel aus der Steuerkammer, in der der Lastdruck gehalten wird, unter Umgehung des Sitzventiles zur anderen Steuerkammer, sobald es umgeschaltet wird. Dazu dient auch die weitere Steuerleitung, die das Sitzventil umgeht. Ohne das Umschaltventil müßte beispielsweise die Regelfeder der Druckwaage stärker ausgelegt werden.The embodiment of claim 5 is also important because the two-position switch valve ensures that the flow resistance of the poppet valve does not enter the control loop, i.e. that the pressure compensator with a small pressure difference can be designed in a sensitive and appealing manner, although the seat valve, which is expediently of a small construction, has a pressure difference which can be a multiple of the pressure difference of the pressure compensator. The changeover valve leads the pressure medium from the control chamber in which the load pressure is maintained, bypassing the seat valve to the other control chamber as soon as it is switched over. The other control line that bypasses the seat valve also serves this purpose. Without the changeover valve, for example, the control spring of the pressure compensator would have to be designed more strongly.

Zweckmäßig ist ferner die Ausführungsform gemäß Anspruch 6, weil das Sitzventil unter der Wirkung der Federkraft seine Absperrstellung selbsttätig einnimmt, wenn die Steuervorrichtung in die Nullstellung gebracht wird.The embodiment according to claim 6 is also expedient because the seat valve automatically assumes its shut-off position under the action of the spring force when the control device is brought into the zero position.

Ein feinfühliges Ansprechen und eine einfache Handhabung werden bei der Ausführungsform gemäß Anspruch 7 erreicht, wobei ein modernes kleines Sitzventil preiswert ist und mit einem kleinen und preiswerten Magneten auskommt.A sensitive response and easy handling are achieved in the embodiment according to claim 7, wherein a modern small seat valve is inexpensive and manages with a small and inexpensive magnet.

Günstig ist ferner das Merkmal von Anspruch 8, weil das Umschaltventil unter der Wirkung der Federkraft selbsttätig seine erste Durchgangsstellung einnimmt, in der die druckübertragende Verbindung von der Steuerkammer zur der Meßblende abgewandten Seite des Sitzventils offen ist und der Lastdruck von der Meßblende ferngehalten wird und direkt am Regelkolbenende ansteht und den Regelkolben in seiner Haltestellung hält.The feature of claim 8 is also advantageous because the changeover valve automatically assumes its first passage position under the action of the spring force, in which the pressure-transmitting connection from the control chamber to the side of the seat valve facing away from the measuring orifice is open and the load pressure is kept away from the measuring orifice and directly is at the end of the control piston and holds the control piston in its stop position.

Wichtig ist auch der Gedanke von Anspruch 9, weil ein magnetbetätigtes Umschaltventil, das klein bauend ausgelegt sein kann, preiswert und ansprechsicher ist.The idea of claim 9 is also important because a solenoid-operated changeover valve, which can be designed to be small, is inexpensive and reliable.

Vorteilhaft ist ferner der Gedanke von Anspruch 10, weil durch die Kopplung der Verstelleinrichtungen sichergestellt ist, daß das Absperrglied bzw. Sitzventil und das Umschaltventil jeweils gleichzeitig ihre Stellungen ändern, wenn die Steuervorrichtung umgeschaltet wird.The idea of claim 10 is also advantageous because the coupling of the adjusting devices ensures that the shut-off element or seat valve and the changeover valve each change their positions simultaneously when the control device is switched over.

Eine weitere, vorteilhafte Ausführungsform geht aus Anspruch 11 hervor. In der Versorgungsleitung wird nur dann Druck eingespeist, wenn der Hydromotor gegen die Last zu bewegen ist, wobei die Meßblende mit der Druckwaage soviel Druckmittel in den Tank abfließen lassen, daß die an der Meßblende eingestellte Bewegungsgeschwindigkeit des Hydromotors unabhängig von der Last eingehalten wird. Sofern ein Sitzventil vorgesehen ist, befindet sich dies in seiner Durchgangsstellung, damit der Überschuß an Druckmittel, der entweder durch die Druckwaage oder durch eine dafür zusätzlich vorgesehene Steuervorrichtung (z.B. ein weiterer Stromregler) nicht in den Tank abströmt, dem Hydromotor zugeführt wird. Ist ein Umschaltventil vorgesehen, so befindet sich dies bei Verwendung der Druckwaage zur Steuerung in beiden Richtungen zusammen mit dem Sitzventil in einer Stellung, in der eine druckübertragende Verbindung von der dem Sitzventil zugewandten Seite der Meßblende zur Steuerkammer besteht, damit der Regelkolben an beiden Kolbenenden von den Drücken stromauf und stromab zur Meßblende beaufschlagt wird und das jeweils an der Meßblende eingestellte Druckgefälle einregelt. Ist hingegen ein gesonderter Stromregler für die Steuerung bei beaufschlagter Versorgungsleitung vorgesehen, so bleibt die Druckwaage in der Absperrstellung.Another advantageous embodiment is set out in claim 11. Pressure is only fed into the supply line when the hydraulic motor can be moved against the load, the metering orifice with the pressure compensator allowing so much pressure medium to flow into the tank that the speed of movement of the hydraulic motor set on the metering orifice is maintained regardless of the load. If a seat valve is provided, this is in its open position so that the excess pressure medium, which does not flow into the tank either through the pressure compensator or through an additional control device (e.g. another current regulator), is fed to the hydraulic motor. Is a changeover valve provided, this is when using the pressure compensator for control in both directions together with the poppet valve in a position in which there is a pressure-transmitting connection from the side facing the poppet valve to the control chamber, so that the control piston at both piston ends of the pressures upstream and is acted upon downstream of the orifice plate and regulates the pressure drop set in each case on the orifice plate. If, on the other hand, a separate current regulator is provided for the control when the supply line is loaded, the pressure compensator remains in the shut-off position.

Eine weitere, alternative Ausführungsform geht schließlich aus Anspruch 12 hervor. Hierbei wird aus der Versorgungsleitung wenigstens ein weiterer Hydromotor mit Druckmittel versorgt, wobei für die Bewegungssteuerung dieses weiteren Hydromotors die gleiche Meßblende und Druckwaage verwendet wird, wie für den ersten Hydromotor. Der jeweils nicht angesteuerte Hydromotor wird durch sein Sitzventil von der Versorgungsleitung abgetrennt. Das Umschaltventil sorgt trotzdem dafür, daß der Regelkolben der Druckwaage an beiden Kolbenenden mit den stromauf und stromab zur Meßblende herrschenden Drücken beaufschlagt wird und die an der Meßblende eingestellte Druckdifferenz unabhängig vom Lastdruck oder Versorgungsdruckschwankungen hält. An die Versorgungsleitung können auch weitere Verbraucher angeschlossen werden, die jeweils für sich über die Meßblende und die Druckwaage ansteuerbar sind. An die Steuerkammer wird entweder nur der Lastdruck des am stärksten belasteten Hydromotors übertragen oder es ist dafür gesorgt, daß bei Lastdrucksteuerleitungen zu jedem Hydromotor diejenigen abgesperrt werden, die gerade niedrigere Lastdrücke aufweisen.Another alternative embodiment finally emerges from claim 12. In this case, at least one further hydraulic motor is supplied with pressure medium from the supply line, the same measuring orifice and pressure compensator being used for the movement control of this further hydraulic motor as for the first hydraulic motor. The non-controlled hydraulic motor is separated from the supply line by its seat valve. The changeover valve nevertheless ensures that the control piston of the pressure compensator is acted upon at both piston ends by the pressures prevailing upstream and downstream of the measuring orifice and that the pressure difference set on the measuring orifice is independent of the load pressure or supply pressure fluctuations. Additional loads can also be connected to the supply line, each of which can be controlled individually via the measuring orifice and the pressure compensator. Only the load pressure of the most heavily loaded hydraulic motor is transmitted to the control chamber, or it is ensured that those that have lower load pressures are shut off in the case of load pressure control lines for each hydraulic motor.

Anhand der Zeichnung werden nachstehend Ausführungsformen des Erfindungsgegenstandes erläutert.
Es zeigen:

Fig. 1
in schematischer Darstellung eine hydraulische Steuervorrichtung für einen einseitig gegen eine Last beaufschlagbaren Hydromotor,
Fig. 2
eine abgeänderte Ausführungsform und
Fig. 3
eine weitere Ausführungsform für entweder einen Hydromotor oder für mehrere Hydromotoren.
Embodiments of the subject matter of the invention are explained below with the aid of the drawing.
Show it:
Fig. 1
a schematic representation of a hydraulic control device for a hydraulic motor which can be loaded on one side against a load,
Fig. 2
a modified embodiment and
Fig. 3
a further embodiment for either one hydraulic motor or for several hydraulic motors.

Aus Fig. 1 ist ein hydraulischer Steuerkreis mit einer hydraulischen Steuervorrichtung 1 für einen einseitig gegen eine Last beaufschlagbaren Hydromotor 2 erkennbar. Es handelt sich dabei beispielsweise um eine Hubsteuervorrichtung für den Hubkolben eines Hubstaplers oder einer Ladebordwand.1 shows a hydraulic control circuit with a hydraulic control device 1 for a hydraulic motor 2 which can be acted upon on one side against a load. This is, for example, a lifting control device for the lifting piston of a forklift or a tail lift.

Der Hydromotor 2 ist ein Zylinder 3, in dem ein Kolben 4 unter einer Last 5, z.B. das Gewicht der Hubgabelhalterung eines Hubstaplers, verschiebbar oder hydraulisch blockierbar ist. Zum Verschieben des Kolbens 4 gegen die Last 5 ist an den Zylinder 3 eine aus einer Druckquelle 6, z.B. einer zuschaltbaren Hydraulikpumpe, gespeiste Versorgungsleitung 7 über ein Rückschlagventil 8 angeschlossen.The hydraulic motor 2 is a cylinder 3, in which a piston 4 under a load 5, e.g. the weight of the lifting fork bracket of a forklift truck is slidable or hydraulically lockable. To move the piston 4 against the load 5, a pressure source 6, e.g. a switchable hydraulic pump, supply line 7 connected via a check valve 8.

Die Versorgungsleitung 7 kreuzt eine Ablaßleitung 32 vom Zylinder 3 zu einem Tank 37. In der Ablaßleitung 32 ist eine Meßblende 9 mit einem verstellbaren Meßblendenglied 10 angeordnet, die ein in eine lasthaltende Absperrstellung bringbares Absperrglied A ist. Zur Verstellung dient eine Stellbetätigung 11, im vorliegenden Fall ein Stellmagnet bzw. Proportionalmagnet.The supply line 7 crosses a drain line 32 from the cylinder 3 to a tank 37. In the drain line 32 is a measuring orifice 9 with an adjustable orifice member 10 is arranged, which is a shut-off element A which can be brought into a load-holding shut-off position. An actuating actuator 11 is used for adjustment, in the present case an actuating magnet or proportional magnet.

Stromab der Meßblende 9 ist in die Ablaßleitung 32 ein Gehäuse 13 einer Druckwaage 12 eingesetzt, die eine Regelblende 14 enthält, die in üblicher Weise die an der Meßblende 9 eingestellte Druckdifferenz und damit die Geschwindigkeit des Kolbens 4 einregelt. In einer Gehäusebohrung 29 ist eine Ringkammer 15 mit einer Steuerkante 16 vorgesehen. Ein in der Gehäusebohrung 29 verschiebbar geführter Regelkolben 17 besitzt zwei über eine Kolbenstange 20 und eine Eindrehung 19 miteinander verbundene Kolbenteile 22 und 21. Eine Seite des Kolbenteils 21 bildet eine Steuerkante 18, die mit der Steuerkante 16 blendenartig zusammenarbeitet, wenn der Regelkolben 17 sein Arbeitsspiel ausführt.Downstream of the orifice 9, a housing 13 of a pressure compensator 12 is inserted into the drain line 32, which contains a control orifice 14, which regulates the pressure difference set on the orifice 9 and thus the speed of the piston 4 in a conventional manner. An annular chamber 15 with a control edge 16 is provided in a housing bore 29. A control piston 17, which is displaceably guided in the housing bore 29, has two piston parts 22 and 21 connected to one another via a piston rod 20 and a recess 19. One side of the piston part 21 forms a control edge 18, which cooperates with the control edge 16 like an aperture when the control piston 17 performs its working cycle executes.

Das in Fig. 1 linke Kolbenende 23 des Regelkolbens 17 liegt in einer Steuerkammer 30 am linken Ende der Gehäusebohrung 20. Die Steuerkammer 30 enthält eine Regelfeder 35 und steht über einen Kanal 34 mit einem an die Ablaßleitung 32 stromab der Meßblende 9 angeschlossenen Kanal 33 zum mittleren Teil der Gehäusebohrung 29 in Verbindung. Der Kanal 33 könnte auch weggelassen werden, wenn das Kolbenende 23 gleichzeitig die Steuerkante 18 bildet. Dann würde Druckmittel direkt aus der Steuerkammer 30 über die Regelblende 14 abströmen.The left piston end 23 of the control piston 17 in FIG. 1 lies in a control chamber 30 at the left end of the housing bore 20. The control chamber 30 contains a control spring 35 and is connected via a channel 34 to a channel 33 connected to the discharge line 32 downstream of the orifice plate 9 middle part of the housing bore 29 in connection. The channel 33 could also be omitted if the piston end 23 forms the control edge 18 at the same time. Then pressure medium would flow directly out of the control chamber 30 via the control orifice 14.

Das rechte Kolbenende 24 des Regelkolbens 17 befindet sich in einer Steuerkammer 31 am rechten Ende der Gehäusebohrung 29, deren Innendurchmesser hier größer ist, als der Innendurchmesser der Gehäusebohrung 29. Die Steuerkammer 31 steht über einen Kanal 39 mit einer Steuerleitung 40 in Verbindung, in der eine Drossel 41 angeordnet ist. Die Steuerleitung 40 ist an die Ablaßleitung 32 zwischen der Meßblende 9 und dem Hydromotor 2 angeschlossen und führt den an der linken Seite des Kolbens 4 herrschenden Lastdruck in die Steuerkammer 31.The right piston end 24 of the control piston 17 is located in a control chamber 31 at the right end of the housing bore 29, the inside diameter of which is larger than the inside diameter of the housing bore 29 Control chamber 31 is connected via a channel 39 to a control line 40 in which a throttle 41 is arranged. The control line 40 is connected to the drain line 32 between the measuring orifice 9 and the hydraulic motor 2 and leads the load pressure prevailing on the left side of the piston 4 into the control chamber 31.

Das rechte Kolbenende 24 ist als Schließelement 25 mit einer kegelförmigen Verdickung 26 ausgebildet. Dem Schließelement 25 ist im Mündungsbereich der Gehäusebohrung 29 in die Steuerkammer 31 ein Ventilsitz 27 zugeordnet, der im vorliegenden Fall an einem Einsatz 28 im Gehäuse 13 angebracht ist. Der Einsatz 28 könnte auch eine durchgehende gehärtete Hülse mit angeschliffenem Ventilsitz sein. Von der Ringkammer 15 führt ein Kanal 36 zu einer Tankleitung 38.The right piston end 24 is designed as a closing element 25 with a conical thickening 26. A valve seat 27 is assigned to the closing element 25 in the mouth region of the housing bore 29 into the control chamber 31, which valve seat is attached to an insert 28 in the housing 13 in the present case. The insert 28 could also be a continuous hardened sleeve with a ground valve seat. A channel 36 leads from the annular chamber 15 to a tank line 38.

Die Steuervorrichtung 1 gemäß Fig. 1 befindet sich in der Nullstellung. Die Druckquelle 6 ist abgeschaltet. Der durch die Last 5 hervorgerufene Druck an der linken Seite des Kolbens 4 wird vom Rückschlagventil 8, ferner vom in der lasthaltenden Absperrstellung stehenden Sperrglied A, d.h. der Meßblende 9 und schließlich vom mit dem Ventilsitz 27 nach Art eines Sitzventils zusammenarbeitenden Schließelement 25 gehalten. Das Druckmittel stromab der Meßblende 9 ist über die geschlossene Regelblende 14 entspannt (konstruktiv bedingte Leckverluste). Dadurch kann der Regelkolben 17 seine Absperrstellung nicht mehr aufgeben.The control device 1 according to FIG. 1 is in the zero position. The pressure source 6 is switched off. The pressure caused by the load 5 on the left side of the piston 4 is from the check valve 8, further from the blocking member A, which is in the load-holding shut-off position, i.e. the orifice 9 and finally held by the closing element 25 which cooperates with the valve seat 27 in the manner of a seat valve. The pressure medium downstream of the measuring orifice 9 is relaxed via the closed control orifice 14 (leakage losses caused by the design). As a result, the control piston 17 can no longer give up its shut-off position.

Soll der Kolben 4 gegen die Last 5 bewegt werden, so wird die Druckquelle 6 aktiviert. Sofern für diese Bewegungsrichtung nicht eine gesonderte Steuervorrichtung, z.B. zwischen Pumpe 6 und Rückschlagventil 7, vorgesehen ist, wird die Meßblende 9 durch den Magneten 11 in eine Offenstellung verstellt, die der gewünschten Bewegungsgeschwindigkeit des Kolbens 4 entspricht. Sie verliert ihre Funktion des Sperrgliedes A. Die Steuerkammer 30 wird mit Druck beaufschlagt, bis der Regelkolben 17 nach rechts fährt und soviel Druckmittel über die Regelblende 16, 18 läßt, daß der Kolben 4 nur mit der eingestellten Geschwindigkeit nach rechts verfährt, und zwar unabhängig von der Größe oder von Änderungen der Last 5. Ein Schaltruck wird dabei vermieden, weil das Rückschlagventil 8 erst dann öffnet, wenn in der Versorgungsleitung 7 mindestens der gleiche Druck aufgebaut ist, wie er auch in der Steuerkammer 31 herrscht, und weil Druckmittel zum Verstellen des Regelkolbens 17 von der Druckquelle 6 kommt.If the piston 4 is to be moved against the load 5, the pressure source 6 is activated. Unless a separate control device is provided for this direction of movement, for example between pump 6 and check valve 7, the measuring orifice 9 adjusted by the magnet 11 to an open position, which corresponds to the desired speed of movement of the piston 4. It loses its function of the locking member A. The control chamber 30 is pressurized until the control piston 17 moves to the right and leaves enough pressure medium via the control orifice 16, 18 that the piston 4 only moves to the right at the set speed, independently on the size or changes in the load 5. A switching jerk is avoided because the check valve 8 only opens when at least the same pressure is built up in the supply line 7 as that prevails in the control chamber 31, and because pressure medium for adjustment of the control piston 17 comes from the pressure source 6.

Soll der Kolben 4 - ausgehend von der Nullstellung -unter der Last 5 in Fig. 1 nach links verschoben werden, so wird die Druckquelle 6 nicht aktiviert. Vielmehr wird die Meßblende 9 in eine Stellung verstellt, die der gewünschten Bewegungsgeschwindigkeit des Kolbens 4 entspricht. Die Meßblende 9 gibt damit ihre Funktion als Sperrglied A auf. Unter dem Lastdruck stehendes Druckmittel wird aus der Steuerkammer 31 über die Steuerleitung 40, den Kanal 33 und den Kanal 34 in die Steuerkammer 30 verlagert; die Regelblende 14 öffnet. Da keine nennenswerte positive Überdeckung zwischen den Steuerkanten 18, 16 gebraucht wird, weil der Lastdruck am Sperrglied A anstand, wird für Aufsteuern der Regelblende 14 kein spürbares Volumen benötigt. Da die Regelfeder 35 zusätzlich wirksam ist, verschiebt sich der Regelkolben 17 nach rechts, wobei das Volumen, das durch die Verschiebung des Regelkolbens 17 nach rechts aus der Steuerkammer 31 verdrängt wird, der Steuerkammer 30 zugeführt wird. Es unterbleibt aus diesem Grund ein Schaltruck.If the piston 4 is to be shifted to the left under the load 5 in FIG. 1, starting from the zero position, the pressure source 6 is not activated. Rather, the orifice 9 is adjusted to a position which corresponds to the desired speed of movement of the piston 4. The measuring orifice 9 thus gives up its function as a blocking element A. Pressure medium under the load pressure is shifted from the control chamber 31 via the control line 40, the channel 33 and the channel 34 into the control chamber 30; the control panel 14 opens. Since no appreciable positive overlap between the control edges 18, 16 is needed because the load pressure was applied to the blocking element A, no noticeable volume is required for opening the control orifice 14. Since the control spring 35 is also effective, the control piston 17 shifts to the right, the volume which is displaced from the control chamber 31 by the displacement of the control piston 17 to the right being fed to the control chamber 30. For this reason, there is no shift jerk.

Da es in der Praxis schwierig ist, die Meßblende 9 gemäß Fig. 1 so auszubilden, daß sie in der Absperrstellung als Sperrglied A arbeitet, ist bei der Ausführungsform von Fig. 2 dem Hydromotor 2 stromauf der Meßblende 9 ein Sitzventil 42 zugeordnet, das unter der Kraft einer Feder 43 seine Absperrstellung selbsttätig einnimmt und durch ein Betätigungsglied 44, z.B. einen Schaltmagneten, in eine Durchgangsstellung verstellbar ist. Das Sitzventil 42 bildet in der Absperrstellung das Sperrglied Aʹ. Die Steuerleitung 40 ist an die Ablaßleitung 32 zwischen dem Sitzventil 42 und dem Hydromotor 2 angeschlossen. In der Nullstellung der Steuervorrichtung 1ʹ, deren Druckwaage 12 der von Fig. 1 entspricht, wird der Lastdruck des Hydromotors 2 somit vom Sitzventil 42 und vom Schließelement 25 auf dem Ventilsitz 27 aufgenommen. Die Meßblende 9 kann demzufolge in der Nullstellung ohne weiteres offenbleiben. Dies bedeutet auch, daß, z.B. für eine Ladebordwandsteuerung mit konstanter Bewegungsgeschwindigkeit des Hydromotors 2, eine festeingestellte Meßblende 9 verwendet werden kann.Since it is difficult in practice to design the metering orifice 9 according to FIG. 1 so that it works in the shut-off position as a blocking member A, the hydraulic motor 2 is assigned a seat valve 42 upstream of the metering orifice 9 in the embodiment of FIG the force of a spring 43 assumes its shut-off position automatically and by an actuator 44, for example a switching magnet, is adjustable in a through position. The seat valve 42 forms the blocking member Aʹ in the shut-off position. The control line 40 is connected to the drain line 32 between the seat valve 42 and the hydraulic motor 2. In the zero position of the control device 1ʹ, whose pressure compensator 12 corresponds to that of FIG. 1, the load pressure of the hydraulic motor 2 is thus taken up by the seat valve 42 and by the closing element 25 on the valve seat 27. The measuring orifice 9 can therefore easily remain open in the zero position. This also means that e.g. for a tail lift control with constant speed of movement of the hydraulic motor 2, a fixed measuring orifice 9 can be used.

Zum Bewegen des Hydromotors 2 gegen die Last werden in der Nullstellung zunächst die Druckquelle 6 aktiviert und das Sitzventil 42 in seine Durchgangsstellung geschaltet. Danach wird in Abhängigkeit von der Einstellung der Meßblende 9 der Kolben des Hydromotors 2 gegen die Last bewegt. Das Druckmittel aus der Steuerkammer 31 wird unter dem Lastdruck mit dem Volumen in die Steuerkammer 30 verlagert, das der Regelkolben 17 verdrängt. Ein Schaltruck tritt nicht auf. Ist eine separate Steuervorrichtung für diese Bewegungsrichtung verwendet (z.B. zwischen der Druckquelle 6 und dem Rückschlagventil 7), dann wird die Meßblende 9 in der Absperrstellung gehalten. Die Druckwaage 12 arbeitet nicht.To move the hydraulic motor 2 against the load, the pressure source 6 is first activated in the zero position and the seat valve 42 is switched to its open position. Then, depending on the setting of the orifice 9, the piston of the hydraulic motor 2 is moved against the load. The pressure medium from the control chamber 31 is displaced under the load pressure with the volume into the control chamber 30 which the control piston 17 displaces. A shift jerk does not occur. If a separate control device is used for this direction of movement (for example between the pressure source 6 and the check valve 7), then the orifice 9 in the Locked position held. The pressure compensator 12 is not working.

Soll der Kolben H des Hydromotors 2 unter der Last bewegt werden, so wird die Druckquelle 6 nicht aktiviert, sondern das Sitzventil 42 in seine Durchgangsstellung geschaltet. In Abhängigkeit von der Einstellung der Meßblende 9 wird entsprechend der Bewegung des Regelkolbens 17 nach rechts Druckmittel unter dem Lastdruck aus der Steuerkammer 31 in die Steuerkammer 30 nach links verdrängt. Ein Schaltruck unterbleibt daher.If the piston H of the hydraulic motor 2 is to be moved under the load, the pressure source 6 is not activated, but the seat valve 42 is switched to its open position. Depending on the setting of the orifice 9, pressure medium is displaced from the control chamber 31 into the control chamber 30 to the left in accordance with the movement of the control piston 17 to the right under the load pressure. There is therefore no switching jerk.

Bei der Ausführungsform der Steuervorrichtung 1ʺ gemäß dem mittleren Teil von Fig. 3 wird wieder die gleiche Druckwaage 12 verwendet, wie bei der Ausführungsform der Figuren 1 und 2. Die Meßblende 9 kann verstellbar oder festeingestellt sein. Zusätzlich ist in der Steuervorrichtung 1ʺ gemäß Fig. 3 ein Zweistellungs-Umschaltventil 45 in der Steuerleitung 40 vorgesehen, die an die Ablaßleitung 32 zwischen dem Sitzventil 42 und dem Hydromotor 2 angeschlossen ist und demzufolge stets den Lastdruck führt. Die Steuerleitung 40 besitzt zwei Teile 40a und 40b, zwischen denen sich das Umschaltventil 45 befindet. Ferner ist eine zweite Steuerleitung 48 vorgesehen, die an die Ablaßleitung 32 zwischen der Meßblende 9 und dem Sitzventil 42 angeschlossen ist und ebenfalls zum Umschaltventil 45 führt. Das Umschaltventil 45 wird durch eine Feder 46 in eine erste Durchgangsstellung gebracht, in der die beiden Teile 40a und 40b der Steuerleitung miteinander verbunden sind und die zweite Steuerleitung 48 abgetrennt ist. Am Umschaltventil ist eine Betätigungseinrichtung 47, z.B. ein Schaltmagnet, vorgesehen, mit der das Umschaltventil 45 in eine zweite Durchgangsstellung bringbar ist, in der eine druckübertragende Verbindung zwischen dem Teil 40b der Steuerleitung 40 und der zweiten Steuerleitung 48 hergestellt ist, während der erste Teil 40a vom Teil 40b getrennt ist. Die Betätigungseinrichtungen des Sitzventils 42 und des Umschaltventils 45 können gegebenenfalls durch eine Kopplung 49 miteinander verbunden sein, so daß sie stets gleichsinnig betätigt werden.In the embodiment of the control device 1ʺ according to the middle part of FIG. 3, the same pressure compensator 12 is used again as in the embodiment of FIGS. 1 and 2. The measuring orifice 9 can be adjustable or fixed. In addition, a two-position switch valve 45 is provided in the control line 40 in the control device 1ʺ according to FIG. 3, which is connected to the drain line 32 between the seat valve 42 and the hydraulic motor 2 and consequently always carries the load pressure. The control line 40 has two parts 40a and 40b, between which the changeover valve 45 is located. Furthermore, a second control line 48 is provided, which is connected to the drain line 32 between the measuring orifice 9 and the seat valve 42 and also leads to the changeover valve 45. The changeover valve 45 is brought into a first through position by a spring 46, in which the two parts 40a and 40b of the control line are connected to one another and the second control line 48 is separated. An actuating device 47, for example a switching magnet, is provided on the changeover valve, with which the changeover valve 45 is converted into a second one Passable position can be brought in which a pressure-transmitting connection between the part 40b of the control line 40 and the second control line 48 is established, while the first part 40a is separated from the part 40b. The actuating devices of the seat valve 42 and the changeover valve 45 can optionally be connected to one another by a coupling 49, so that they are always actuated in the same direction.

Mit dem Umschaltventil 45 und der zweiten Steuerleitung 48 wird erreicht, daß der Durchströmwiderstand des Sitzventils 42 nicht in den Regelkreis der Steuervorrichtung 1ʺ eingeht, sondern daß in der Durchgangsstellung des Sitzventils in der Steuerkammer 31 der Druck herrscht, der zwischen der Meßblende 9 und dem Sitzventil 42 in der Ablaßleitung 32 herrscht.With the changeover valve 45 and the second control line 48 it is achieved that the flow resistance of the seat valve 42 does not enter the control circuit of the control device 1ʺ, but that in the open position of the seat valve in the control chamber 31, the pressure prevails between the metering orifice 9 and the seat valve 42 prevails in the drain line 32.

Soll der Hydromotor 2 gegen die Last bewegt werden, so werden zunächst die Druckquelle 6 aktiviert und die Meßblende 9 für die gewünschte Bewegungsgeschwindigkeit eingestellt. Der Regelkolben befindet sich in seiner Absperrstellung, in der er durch den Lastdruck aus der offenen Steuerleitung 40 gehalten wird. Danach werden das Sitzventil 42 und gleichzeitig über die Kopplung 49 auch das Umschaltventil 45 umgestellt, so daß das Sitzventil 42 seine Durchgangsstellung und das Umschaltventil 45 seine zweite Durchgangsstellung einnehmen, in der der Teil 40b der Steuerleitung 40 mit der zweiten Steuerleitung 48 verbunden und der Teil 40a der Steuerleitung 40 abgetrennt sind. Kurz vor Erreichen des Lastdrucks in der Steuerkammer 30 wird der Regelkolben nach rechts verstellt, so daß die Regelblende allmählich zu öffnen beginnt. Das Volumen, das bei dieser Verstellung des Regelkolbens in der Steuerkammer 31 verdrängt wird, wird über den Teil 40b, das Umschaltventil 45, die Steuerleitung 48 und die Ablaßleitung 32 der Steuerkammer 30 zugeführt, so daß ein Schaltruck zuverlässig unterbleibt. Ist für diese Bewegungsrichtung eine getrennte Steuervorrichtung (z.B. ein Stromregler) vorgesehen, dann arbeitet die Druckwaage 12 nicht. Der jeweilige Lastdruck wird in der Nullstellung gehalten.If the hydraulic motor 2 is to be moved against the load, the pressure source 6 is first activated and the measuring orifice 9 is set for the desired movement speed. The control piston is in its shut-off position, in which it is held by the load pressure from the open control line 40. Thereafter, the seat valve 42 and, at the same time, the switching valve 45 are switched via the coupling 49, so that the seat valve 42 assumes its passage position and the switching valve 45 its second passage position, in which the part 40b of the control line 40 is connected to the second control line 48 and the part 40a of the control line 40 are separated. Shortly before the load pressure in the control chamber 30 is reached, the control piston is moved to the right, so that the control orifice begins to open gradually. The volume that is in this adjustment of the control piston in the Control chamber 31 is displaced, is supplied via part 40b, the changeover valve 45, the control line 48 and the drain line 32 to the control chamber 30, so that a switching jolt is reliably avoided. If a separate control device (for example a current regulator) is provided for this direction of movement, the pressure compensator 12 does not work. The respective load pressure is kept in the zero position.

Zum Bewegen des Hydromotors 2 unter der Last werden -ausgehend von der Nullstellung - das Sitzventil 42 in die Durchgangsstellung und das Umschaltventil 45 in seine zweite Durchgangsstellung verstellt, damit die Steuerkammern 30, 31 mit den Drücken stromauf und stromab der Meßblende 9 beaufschlagt sind und der Strömungswiderstand des Sitzventils 42 nicht in das Regelverhalten eingeht. Der Einstellung der Meßblende 9 entsprechend wird die Regelblende 14 aufgesteuert. Das der Bewegung des Regelkolbens 17 entsprechende Druckmittelvolumen wird aus der Steuerkammer 31 in die Steuerkammer 30 verdrängt. Ein Schaltruck unterbleibt.To move the hydraulic motor 2 under the load - starting from the zero position - the poppet valve 42 is moved into the through position and the changeover valve 45 into its second through position so that the control chambers 30, 31 are acted upon with the pressures upstream and downstream of the orifice plate 9 and the Flow resistance of the seat valve 42 is not included in the control behavior. The control orifice 14 is opened in accordance with the setting of the orifice 9. The pressure medium volume corresponding to the movement of the control piston 17 is displaced from the control chamber 31 into the control chamber 30. There is no switching jerk.

Soll erneut die Nullstellung aufgesucht werden, so wird das Sitzventil 42 zusammen mit dem Umschaltventil 45 umgeschaltet. Der Lastdruck wird wieder vom Sitzventil 42 und vom Sitzventil zwischen dem Schließelement 25 und dem Ventilsitz 27 gehalten. Die zweite Steuerleitung 48 ist abgetrennt. Die Steuerkammer 30 ist über die Regelblende 14 entlastet.If the zero position is to be sought again, the seat valve 42 is switched over together with the changeover valve 45. The load pressure is again held by the seat valve 42 and the seat valve between the closing element 25 and the valve seat 27. The second control line 48 is disconnected. The control chamber 30 is relieved via the control panel 14.

Wie Fig. 3 andeutet, kann die Steuervorrichtung 1ʺ durch Hinzunahme wenigstens eines weiteren Hydromotors 2ʹ zu einer Steuervorrichtung 1 "' erweitert werden, mit der es möglich ist, mehrere Hydromotoren 2, 2ʹ mit der gemeinsamen Meßblende 9 und der gemeinsamen Druckwaage 12 sowie dem gemeinsamen Umschaltventil 45 lastdruckunabhängig zu steuern. Der weitere Hydromotor 2ʹ ist über seine Ablaßleitung 32ʹ an die Versorgungsleitung 7 angeschlossen. In der Ablaßleitung 32ʹ ist ein dem Sitzventil 32 entsprechendes Sitzventil 42ʹ angeordnet, das in der Absperrstellung den Lastdruck des Hydromotors 2ʹ hält und in seiner Durchgangsstellung das Ablassen bzw. Zuführen des Druckmittels gestattet. Eine dem Teil 40a der Steuerleitung 40 entsprechende Steuerleitung 40aʹ kann von der Ablaßleitung 32ʹ zwischen dem Sitzventil 42ʹ und dem Hydromotor 2ʹ zum Steuerleitungsteil 40a und somit zum Umschaltventil 45 führen. Zweckmäßigerweise sind in den Steuerleitungsteilen 40a und 40aʹ Rückschlagventile 51, 52 vorgesehen. Strichpunktiert angedeutete Schnittstellen 50 zeigen, wo und wie der bzw. die weiteren Hydromotoren 2ʹ angeschlossen sind. Hat der Hydromotor 2 den höchsten Lastdruck, so kann der Steuerleitungsteil 40aʹ weggelassen werden.As indicated in FIG. 3, the control device 1ʺ can be expanded by adding at least one further hydraulic motor 2ʹ to a control device 1 ″ ', with which it is possible to use several hydraulic motors 2, 2ʹ with the common measuring orifice 9 and the common pressure compensator 12 and the common switch valve 45 to control independent of the load pressure. The further hydraulic motor 2ʹ is connected via its drain line 32ʹ to the supply line 7. In the drain line 32ʹ a seat valve 42ʹ corresponding to the seat valve 32 is arranged, which holds the load pressure of the hydraulic motor 2ʹ in the shut-off position and allows the pressure medium to be released or supplied in its through position. A control line 40aʹ corresponding to part 40a of control line 40 can lead from drain line 32ʹ between seat valve 42ʹ and hydraulic motor 2ʹ to control line part 40a and thus to changeover valve 45. Check valves 51, 52 are expediently provided in the control line parts 40a and 40aʹ. Interfaces 50 indicated by dash-dotted lines show where and how the other hydraulic motor (s) 2ʹ are connected. If the hydraulic motor 2 has the highest load pressure, the control line part 40aʹ can be omitted.

Zweckmäßigerweise werden die Hydromotoren 2, 2ʹ einzeln angesteuert, d.h. sobald sich ein Hydromotor bewegt, bleibt der andere in seiner lasthaltenden Stellung.The hydraulic motors 2, 2ʹ are expediently controlled individually, i.e. as soon as one hydraulic motor moves, the other remains in its load-holding position.

Der besondere Vorteil der einzelnen Ausführungsformen der Steuervorrichtung 1, 1ʺ, 1"' liegt darin, daß beim Umschalten der Steuervorrichtung aus der Nullstellung in eine Stellung zum Bewegen des Hydromotors unter der Last ein Schaltruck unterbleibt, weil das zwischen dem Schließelement 25 und dem Ventilsitz 27 gebildete Sitzventil in der Druckwaage praktisch leckagefrei arbeitet, so daß auch über längere Stillstandszeiten kein Druckmittel verlorengeht, sondern zum Bewegungsbeginn von dem unter dem Lastdruck stehenden Druckmittel in der Steuerkammer mit dem Sitzventil genau das Volumen entnommen und in die andere Steuerkammer überführt wird, das zu einer Aufsteuerung der Regelblende ohne den unerwünschten Schaltruck benötigt wird. Dieses Volumen wird sozusagen in einem in die Steuervorrichtung integrierten Druckspeicher zum Abruf bereitgehalten, ohne daß die Druckquelle dazu beizutragen hätte.The particular advantage of the individual embodiments of the control device 1, 1ʺ, 1 "'is that when the control device is switched from the zero position to a position for moving the hydraulic motor under load, there is no switching jerk because this occurs between the closing element 25 and the valve seat 27 formed seat valve in the pressure compensator works practically leak-free, so that no pressure medium is lost even over longer downtimes, but exactly at the beginning of the movement of the pressure medium under load pressure in the control chamber with the seat valve the volume is removed and transferred to the other control chamber, which is required to open the control panel without the undesirable switching jerk. This volume is, so to speak, held ready for retrieval in a pressure accumulator integrated in the control device, without the pressure source having to contribute to this.

Claims (12)

  1. A hydraulic control device (1, 1', 1", 1"'), more particularly a raising control-device for at least one hydraulic motor (2, 2'), which is adapted to be actuated on one side against a load (5), holds the load when stationary and is movable by the load in both directions, the control device having a two-way flow regulator in a discharge line (32) to a tank (37), the flow regulator having an orifice gauge (9) and a pressure-compensating-device (12), the latter having an adjustable gauge (14) controlled by an adjustment piston (17) movable in a casing bore (29) between an open position and the holding or withstanding position, the piston ends (23, 24) being disposed in two control chambers (31, 30), the chamber (30) in which the piston end (23) activatable towards the open position of the piston (17) is disposed being energisable by the pressure downstream of the orifice gauge (9) while the control chamber (31) in which the piston end (24) energisable towards the withstanding or holding position of the piston (17) is disposed is energisable by the pressure upstream of the orifice gauge (9), characterised in that the piston end (24) energisable by the pressure upstream of the orifice gauge (9) has a closure member (25), a valve seat (27) in the control chamber (31) is associated with the closure member (25), when the piston (17) is in the withstanding or holding position the closure member (25) co-operates with the valve seat (27) in the fashion of a seat valve, and the discharge line (32) comprises a shutoff element (A, A') adjustable into a load-pressure-withstanding shutoff position.
  2. A control device (1, 1', 1", 1"') according to claim 1, characterised in that the shutoff element (A) is the orifice gauge (9) movable into a sealing shutoff position.
  3. A control device according to claim 1, characterised in that the shutoff element (A') is a seat valve (42, 42') disposed upstream of the orifice gauge (9) and the control chamber (31) is connected to the discharge line (32) on that side of the seat valve (42, 42') which is remote from the orifice gauge (9).
  4. A control device according to claims 1 to 3, characterised in that the control chamber (31) has an inner diameter greater than the casing bore (29), the valve seat (27) is disposed in the control chamber (31) near the exit zone of the casing bore (29) and is conical and the closure member (25) is embodied by a conical thickening (26) at the end (24) of the piston (17).
  5. A control device according to claims 1 to 4, characterised in that a two-position changeover valve (45) is provided in a first control line (40) enabling the pressure effective on the seat valve side remote from the orifice gauge (9) to be transmitted to the control chamber (31) and a further control line (48) extends from the changeover valve (45) to the discharge line (32) upstream of the orifice gauge (9).
  6. A control device according to claims 3 to 5, characterised in that the seat valve (42, 42') is adjustable against spring force from its shutoff position into an open position.
  7. A control device according to claim 6, characterised in that the seat valve (42, 42') is magnetically operated.
  8. A control device according to claim 5, characterised in that the changeover valve (45) is adjustable against spring force from its first open position, in which the first control line (40) is open to the control chamber (31), into a second open position in which the control chamber (31) is connected to the second control line (48).
  9. A control device according to claim 8, characterised in that the changeover valve (45) is magnetically operated.
  10. A control device according to claims 2 to 8, characterised in that the adjusters (47, 44) of the shutoff element (A, A'), e.g. the seat valve (42), and of the changeover valve (45) are respectively coupled together for respective joint adjustment of the items with which they are associated.
  11. A control device according to at least one of claims 1 to 10, characterised in that upstream of the orifice gauge (9) the discharge line (32) crosses a feed line (7) which is supplied from a pressure source (6) and which feeds a hydraulic motor working in one direction against a load.
  12. A control device according to at least one of claims 1 to 11, characterised in that the feed line (7) crosses at least one other discharge line (32') of another hydraulic motor (2') which is working in one direction against a load and for which a seat valve (42') is provided in the further discharge line (32'), and a control line (40'a) to the changeover valve (45) common to all the hydraulic motors (2, 2') is, if required, provided between the seat valve (42') and the further hydraulic motor (2').
EP88101810A 1987-02-18 1988-02-08 Hydraulic control device Expired - Lifetime EP0279315B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT88101810T ATE68243T1 (en) 1987-02-18 1988-02-08 HYDRAULIC CONTROL DEVICE.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3705170 1987-02-18
DE3705170A DE3705170C1 (en) 1987-02-18 1987-02-18 Hydraulic control device

Publications (3)

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EP0279315A2 EP0279315A2 (en) 1988-08-24
EP0279315A3 EP0279315A3 (en) 1990-03-07
EP0279315B1 true EP0279315B1 (en) 1991-10-09

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US (1) US4811649A (en)
EP (1) EP0279315B1 (en)
JP (1) JP2744004B2 (en)
AT (1) ATE68243T1 (en)
DE (2) DE3705170C1 (en)
ES (1) ES2026213T3 (en)
FI (1) FI89298C (en)
GR (1) GR3003518T3 (en)

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Also Published As

Publication number Publication date
GR3003518T3 (en) 1993-03-16
EP0279315A3 (en) 1990-03-07
FI89298C (en) 1993-09-10
ES2026213T3 (en) 1992-04-16
US4811649A (en) 1989-03-14
JPS63225701A (en) 1988-09-20
FI880600A (en) 1988-08-19
EP0279315A2 (en) 1988-08-24
ATE68243T1 (en) 1991-10-15
FI880600A0 (en) 1988-02-10
DE3865313D1 (en) 1991-11-14
FI89298B (en) 1993-05-31
JP2744004B2 (en) 1998-04-28
DE3705170C1 (en) 1988-08-18

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