EP0958455B1 - Hydraulic control circuit for a priority and for a secondary hydraulic consumer - Google Patents

Hydraulic control circuit for a priority and for a secondary hydraulic consumer Download PDF

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Publication number
EP0958455B1
EP0958455B1 EP97952950A EP97952950A EP0958455B1 EP 0958455 B1 EP0958455 B1 EP 0958455B1 EP 97952950 A EP97952950 A EP 97952950A EP 97952950 A EP97952950 A EP 97952950A EP 0958455 B1 EP0958455 B1 EP 0958455B1
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EP
European Patent Office
Prior art keywords
pressure
hydraulic
valve
control
load
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
EP97952950A
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German (de)
French (fr)
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EP0958455A1 (en
Inventor
Werner Herfs
Jacques Maffini
Thomas Weickert
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Bosch Rexroth AG
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Bosch Rexroth AG
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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
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • 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
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
    • F15B11/163—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load for sharing the pump output equally amongst users or groups of users, e.g. using anti-saturation, 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
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
    • F15B11/162—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load for giving priority to particular servomotors or users
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20546—Type of pump variable capacity
    • F15B2211/20553—Type of pump variable capacity with pilot circuit, e.g. for controlling a swash plate
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • F15B2211/3053—In combination with a pressure compensating valve
    • F15B2211/30535—In combination with a pressure compensating valve the pressure compensating valve is arranged between pressure source and directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3105—Neutral or centre positions
    • F15B2211/3111—Neutral or centre positions the pump port being closed in the centre position, e.g. so-called closed centre
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/35—Directional control combined with flow control
    • F15B2211/351—Flow control by regulating means in feed line, i.e. meter-in control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/45—Control of bleed-off flow, e.g. control of bypass flow to the return line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/605—Load sensing circuits
    • F15B2211/6051—Load sensing circuits having valve means between output member and the load sensing circuit
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/605—Load sensing circuits
    • F15B2211/6058—Load sensing circuits with isolator 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
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/75—Control of speed of the output member

Definitions

  • the invention is based on a hydraulic control circuit which is a primary, first hydraulic consumer and a subordinate, second hydraulic consumer with pressure medium can be supplied and the characteristics from the generic term of claim 1.
  • Such a hydraulic control circuit is known from DE 43 28 283 A1 known.
  • the two hydraulic consumers flow the pressure medium each via a metering orifice, the priority, first hydraulic consumers assigned first Orifice plate upstream of a pressure compensator and the subordinate, second hydraulic consumers assigned, a pressure compensator is connected downstream of the second metering orifice. aid of the pressure compensators are supplied with sufficient quantity of pressure medium regardless of the load pressures of the hydraulic consumers maintain constant pressure differences across the metering orifices, so that the flowing to a hydraulic consumer Pressure medium quantity only from the opening cross section of the respective Metering orifice depends.
  • an adjustable hydraulic pump depending on the highest Load pressure can be controlled such that the pressure in an inlet line by a certain pressure difference above the highest Load pressure is.
  • the downstream of the second metering orifice Pressure compensator is in the opening direction from the pressure after the second Orifice plate and in the closing direction from one to the rear Control room applied control pressure, which is usually the highest load pressure of all from the same hydraulic pump supplied hydraulic consumers.
  • each with pressure medium flows through a metering orifice with an upstream pressure compensator, in the closing direction only from the pressure in front of the orifice and in Opening direction only from the load pressure of the respective hydraulic Consumer and is acted upon by a compression spring receives there is no load-independent flow distribution.
  • DE 43 28 283 A1 is now a priority circuit between an LS consumer and one or more LUDV consumers, in which the LS consumer is primarily supplied with pressure medium.
  • a priority valve is provided, one with a Line section connected upstream of the first metering orifice, first connection and one connected to the load signaling line has second connection and its valve member in the direction Open the connection between the first port and the second Connection of the load pressure of the primary hydraulic consumer, So the LS consumer, and an additional force can be applied is.
  • the priority valve according to the control DE 43 28 283 A1 is towards closing the connection between the first port and the second port of pressure acted on in the second connection. In this way, a priority supply of pressure medium to the LS consumer ensured.
  • the pressure in the supply line is determined in certain Cases unnecessarily high, so that there is a loss of performance. Such a case is e.g.
  • DE 35 07 122 C2 shows a priority control between two LS-consumers. These two hydraulic consumers are flowing So pressure medium amount each via an orifice and this metering orifice upstream pressure compensator in the closing direction is acted upon by the pressure in front of the metering orifice.
  • the Pressure compensator assigned to the primary hydraulic consumer is in the opening direction from the load pressure of this hydraulic Consumer and acted upon by a compression spring.
  • the pressure compensator for the subordinate hydraulic consumer is also in the closing direction by a compression spring and also pressurized between a fixed throttle and a proportional orifice serving as a priority valve is tapped between the fixed choke and one Tank line is switched and from the pressure difference on the metering orifice of the primary hydraulic consumer controlled becomes.
  • undersaturation i.e. inadequately funded
  • the quantity of pressure medium reduces the pressure difference the metering orifice of the hydraulic to be operated primarily with pressure medium Consumer, so the proportional aperture is something opens, the pressure between her and the fixed throttle drops a little and the pressure balance of the subordinate to be operated with pressure medium hydraulic consumer closes so far that for the priority hydraulic consumers again sufficient pressure medium is available.
  • the aim of the invention is to provide a hydraulic control circuit has the features from the preamble of claim 1 with which is an LS consumer versus one or more LUDV consumers should be primarily supplied with pressure medium, so to develop that excessively high power losses in operation be avoided.
  • Control circuit can be found in the subclaims.
  • the pressure difference at the first orifice is from the priority valve sensed. Since in the event of undersaturation the the first metering orifice upstream of the pressure compensator is completely open, can a control room on the valve member of the priority valve according to Claim 4 upstream of the first pressure compensator with the feed line be connected. This can be advantageous in terms of construction Design of the individual components of the control his. In terms of construction, it may also be an advantage if according to claim 5 a control pressure chamber on the valve member of the Priority valve and the first connection of the priority valve on the same side of the first pressure compensator with the inlet to the first Orifice plate are connected.
  • a bypass line around the priority valve provided around that a current point downstream of the first metering orifice connects to the load reporting line and in the one to Check valve opening check valve is arranged.
  • this Load pressure prevails in the load reporting line and if sufficient Pressure medium quantity for all actuated consumers the pressure difference via the first metering orifice from the upstream pressure compensator is determined.
  • the pressure difference is only when there is undersaturation determined by the additional force on the priority valve to which a smaller pressure differential is usually equivalent to the spring force on the first pressure compensator.
  • a variable displacement pump 10 sucks with an adjustment 11 pressure medium from a tank 12 and there is in a system from leads 13.
  • a first is via the supply lines hydraulic consumer 14, which is designed as a synchronous cylinder is, and at least a second hydraulic consumer 15, which is a differential cylinder, supplied with pressure medium.
  • the direction and speed of the synchronous cylinder 14 by a corresponding actuation of a 4/3 proportional directional valve 16 determines whose valve spool is in a central position is spring-centered, in which the four working connections and a control connection 18 of the directional control valve 16 are blocked.
  • the control terminal 18 is downstream of the metering orifice with the flow to the synchronous cylinder 14 connected.
  • a 2-way pressure compensator 20 is inserted, whose control piston in the direction of closing the pressure upstream Metering orifice 17 and in the direction of opening via a control line 61 from the pressure in the control port 18 of the directional control valve 16, that is from Load pressure of the synchronous cylinder 14, and from a control spring 21 is applied.
  • the force of the control spring 21 is designed that you have a pressure difference of e.g. 15 bar via an orifice 17 is equivalent.
  • the one associated with the first hydraulic consumer 14 first pressure compensator 20 upstream of the first orifice 17 is the second hydraulic consumer 15th assigned second pressure compensator 30 to a second metering orifice 31 downstream.
  • a directional control valve 32 is arranged, in comparison for the pressure drop at the metering orifice 31, no significant Pressure drop occurs more when the differential cylinder 15 is actuated becomes.
  • the metering orifice 31 and that for direction control necessary control grooves are in a known manner on the same valve spool trained so that direction and speed control go together without further ado.
  • the Control piston 33 of the pressure compensator 30 is opened towards the front the connection between the metering orifice 31 and the directional control valve 32 from the pressure after the metering orifice and backwards in the direction Closing the connection of one in a control pressure chamber 34 prevailing control pressure and a weak compression spring 35, which is a pressure of e.g. is equivalent to only 0.5 bar.
  • the front of the control piston 33 is in a Control piston extending channel 36 with the control pressure chamber 34 connected, one in the channel 36 to the control pressure chamber opening check valve 37 is arranged.
  • the pressure compensator 30 and the directional control valve 32 for the second hydraulic consumer 15 can additional metering orifices, pressure compensators and directional valves for others hydraulic consumers connected to the system of the feed lines 13 his.
  • the control pressure chambers 34 are all pressure compensators 30 connected to each other, so that in these control pressure rooms the same pressure is applied.
  • the control pistons 33 of the pressure compensators look for themselves when actuating a second hydraulic To bring the consumer into such a position in which to their front one only around that of the force of the compression spring 35 equivalent pressure difference sets higher pressure than in the Control pressure rooms 34.
  • the control pressure chambers 34 are connected to a load signaling line 38, which leads to the adjustment 11 of the pump 10.
  • the load reporting line 38 leads, as can be seen from Figure 4, the load reporting line 38 to a control valve 39 with three connections, one of which one connected to an actuating cylinder 40 of the variable displacement pump 10 is.
  • Another connection of the control valve 39 is with a supply line 13 and the third connection to tank 12.
  • the control piston of the control valve 39 is in the direction of Connection of the first connection with the second connection from Pressure in the supply line 13 and in the direction of a connection of the first connection with the third connection from the pressure in the Load signaling line 38 and acted upon by a control spring 41.
  • Variable pumps and control valves according to the circuit diagram according to the figure 4 are generally known and readily available on the market.
  • the pump control causes that a pressure is established in the feed line 13, which is around a the force of the control spring 41 equivalent pressure difference over the Pressure in the load reporting line 38 is.
  • the pressure difference is e.g. 20 bar, is therefore higher than the force of the control spring 21 of the first pressure compensator 20 equivalent pressure difference of 15 bar.
  • the first hydraulic consumer 14 is to take priority over the second hydraulic consumer 15 supplied with pressure medium become.
  • a priority valve 45 is provided, which as Proportional diaphragm with an input 46 and an output 47 is trained. The latter is connected to the load signaling line 38.
  • the input 46 is upstream of the pressure compensator 20 with a Lead 13 connected.
  • the valve member 48 of the priority valve will close towards the connection between the entrance and the output of one in one connected to a feed line 13 first control pressure chamber 49 prevailing pressure and in Direction of opening the connection from one in a second control pressure chamber prevailing pressure and a control spring 51 applied.
  • the second control pressure chamber 50 is activated of the directional control valve 16 via the control line 61 with one point connected downstream of an orifice 17.
  • the control spring 51 is e.g. designed so that the valve member 48 of the priority valve 45 there is a balance of forces when the pressure in the first control pressure chamber 49 by 13 bar higher than the pressure in second control pressure chamber 50. This pressure difference is lower than that of the force of the control spring 21 of the pressure compensator 20 equivalent Pressure difference.
  • the first hydraulic consumer 14, primarily with pressure medium is to be operated without the priority valve 45 would have to come into operation, always with sufficient pressure medium supplied when the sum of its load pressure plus the control ⁇ p the adjustment 11 on the variable displacement pump 10 is smaller than the highest load pressure of all simultaneously operated second hydraulic consumer 15. Because pressure medium always flows to the hydraulic consumer with the lowest load pressure.
  • the load pressure of the first hydraulic Consumer 14 higher than the highest load pressure of all simultaneously actuated second hydraulic consumer 15 is. It is e.g. 80 bar, while the highest load pressure is the LUDV consumer is 60 bar.
  • the directional valve is actuated 16 are then in the control pressure chamber 50 of the priority valve 45 to 80 bar.
  • 93 bar act in Proportional valve 45 opens in the direction of the control piston Valve then a balance of forces if there are 49 93 bar in the first control pressure chamber.
  • connection 47 of the priority valve 45 there is also between the second connection 47 of the priority valve 45 and the load signaling line 38 a check valve 64 arranged. This blocks to connection 47.
  • the control spring 51 determines the Priority valve 45 the pressure drop at an orifice 17 even if the amount of pressure medium delivered is sufficient, if the load pressure of the hydraulic consumer to be operated as a priority 14 minus the difference between that of the force of the control spring 41 of the control valve 39 equivalent pressure and that of Force of the control spring 51 of the priority valve 45 equivalent Pressure is greater than the highest load pressure of all actuated LUDV consumer 15. Because then 38 in the load reporting line Via the priority valve 45, a pressure is regulated, which is around the Difference between the equivalent pressure of the control spring 41 and the Equivalent pressure of the control spring 51 below the load pressure of the priority hydraulic user 14 is located, e.g. e.g. at a load pressure of 80 bar, an equivalent pressure the control spring 41 of 20 bar and an equivalent pressure of the control spring 51 in the amount of 13 bar is 73 bar. In case of undersaturation the pressure in the load signaling line 38 rises above it Value.
  • the funding is sufficient Pressure medium quantity and load-bearing priority hydraulic Consumer 14 the load pressure of this hydraulic consumer passed via the check valve 63 into the load signaling line 38.
  • the pressure in the system of the feed lines 13 is thus around Equivalent pressure of the control spring 41, that is, the control ⁇ p of the variable displacement pump 10 above the load pressure of the hydraulic consumer 14, i.e. at a load pressure of e.g. 80 bar and one Control ⁇ p of e.g. 20 bar 100 bar.
  • the pressure drop over a metering orifice 17 then becomes as in the case of a load-carrying second Consumer 15 of the force of the control spring 21 of the pressure compensator 20 determined.
  • Priority valve 45 equivalent pressure e.g. to 80 bar plus 13 bar has dropped to 93 bar
  • the pressure drop is via a metering orifice 17 of the directional control valve 16 is 13 bar determined by the force of the control spring 51.
  • Another downsizing the pressure drop across an orifice 17 does not occur because the pressure in the Load reporting line 38 increased via the priority valve 45 and thereby the pressure compensators 30 of the LUDV consumers in the closing direction be adjusted.
  • the check valve 64 prevents a pressure medium flow from the hydraulic Consumer 14 via the check valve 63 in that System of supply lines 13, if e.g. at the start of an operation the pressure in the supply lines is not yet above the load pressure lies.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Jib Cranes (AREA)

Abstract

The invention concerns a hydraulic control circuit in which the pressure medium conveyed by a hydraulic pump of variable delivery (10) is fed, in each case via a metering aperture (17, 31), as a priority to a first hydraulic consumer (14) and only secondly to a second hydraulic consumer (15). A priority control system is now produced without additional delivery losses and with sufficient amounts of pressure medium being conveyed in that the valve member (48) of the priority valve (45) can be acted upon in the closure direction of the connection between the first connection (46) and the second connection (47) by a pressure prevailing in a line section (13) upstream of the first metering aperture (17).

Description

Die Erfindung geht aus von einem hydraulischen Steuerkreis, mit dem ein vorrangiger, erster hydraulischer Verbraucher und ein nachrangiger, zweiter hydraulischer Verbraucher mit Druckmittel versorgt werden können und der die Merkmale aus dem Oberbegriff des Anspruchs 1 aufweist.The invention is based on a hydraulic control circuit which is a primary, first hydraulic consumer and a subordinate, second hydraulic consumer with pressure medium can be supplied and the characteristics from the generic term of claim 1.

Ein solcher hydraulischer Steuerkreis ist aus der DE 43 28 283 A1 bekannt. Den beiden hydraulischen Verbrauchern fließt dabei das Druckmittel jeweils über eine Zumeßblende zu, wobei der dem vorrangigen, ersten hydraulischen Verbraucher zugeordneten ersten Zumeßblende eine Druckwaage vorgeschaltet und der dem nachrangigen, zweiten hydraulischen Verbraucher zugeordneten, zweiten Zumeßblende eine Druckwaage nachgeschaltet ist. Mithilfe der Druckwaagen werden bei ausreichend gelieferter Druckmittelmenge unabhängig von den Lastdrücken der hydraulischen Verbraucher konstante Druckdifferenzen über die Zumeßblenden aufrechterhalten, so daß die einem hydraulischen Verbraucher zufließende Druckmittelmenge nur noch vom Öffnungsquerschnitt der jeweiligen Zumeßblende abhängt. Als Druckmittelquelle dient üblicherweise eine verstellbare Hydropumpe, die in Abhängigkeit vom höchsten Lastdruck derart steuerbar ist, daß der Druck in einer Zulaufleitung um eine bestimmte Druckdifferenz über dem höchsten Lastdruck liegt. Die der zweiten Zumeßblende nachgeschaltete Druckwaage wird in Öffnungsrichtung vom Druck nach der zweiten Zumeßblende und in Schließrichtung von einem in einem rückwärtigen Steuerraum anstehenden Steuerdruck beaufschlagt, der üblicherweise dem höchsten Lastdruck aller von derselben Hydropumpe versorgten hydraulischen Verbraucher entspricht. Werden mehrere hydraulische Verbraucher, denen Druckmittel jeweils über eine Zumeßblende und eine dieser nachgeschalteten Druckwaage, die rückwärtig vom höchsten Lastdruck beaufschlagt ist, zufließt, gleichzeitig betätigt, so werden die ihnen zufließenden Druckmittelmengen verhältnisgleich reduziert, wenn die von der Hydropumpe gelieferte Druckmittelmenge kleiner ist als die geforderten Druckmittelteilmengen. Man spricht in diesem Fall von einer Steuerung mit lastunabhängiger Durchflußverteilung (LUDV-Steuerung). Derart angesteuerte hydraulische Verbraucher werden kurz LUDV-Verbraucher genannt. Weil bei einer LUDV-Steuerung auch der höchste Lastdruck abgefühlt und von der Druckmittelquelle ein um ein bestimmtes Δp über dem höchsten Lastdruck liegender Zulaufdruck erzeugt wird, ist eine LUDV-Steuerung ein Sonderfall einer lastfühlenden oder loadsensing-Steuerung (LS-Steuerung).Such a hydraulic control circuit is known from DE 43 28 283 A1 known. The two hydraulic consumers flow the pressure medium each via a metering orifice, the priority, first hydraulic consumers assigned first Orifice plate upstream of a pressure compensator and the subordinate, second hydraulic consumers assigned, a pressure compensator is connected downstream of the second metering orifice. aid of the pressure compensators are supplied with sufficient quantity of pressure medium regardless of the load pressures of the hydraulic consumers maintain constant pressure differences across the metering orifices, so that the flowing to a hydraulic consumer Pressure medium quantity only from the opening cross section of the respective Metering orifice depends. Usually serves as a pressure medium source an adjustable hydraulic pump, depending on the highest Load pressure can be controlled such that the pressure in an inlet line by a certain pressure difference above the highest Load pressure is. The downstream of the second metering orifice Pressure compensator is in the opening direction from the pressure after the second Orifice plate and in the closing direction from one to the rear Control room applied control pressure, which is usually the highest load pressure of all from the same hydraulic pump supplied hydraulic consumers. Become several hydraulic consumers, which each have a pressure medium Orifice plate and one of these downstream pressure compensators, the is acted upon by the highest load pressure, flows in, actuated at the same time, then the pressure medium quantities flowing to them proportionally reduced if that of the hydraulic pump the quantity of pressure medium supplied is smaller than the required Pressure medium subsets. In this case one speaks of one Control with load-independent flow distribution (LUDV control). Hydraulic consumers controlled in this way LUDV consumers for short. Because with a LUDV control even the highest load pressure is sensed and from the pressure medium source one that is a certain Δp above the highest load pressure Inlet pressure is generated, an LUDV control is on Special case of a load sensing or load sensing control (LS control).

Für mehrere hydraulische Verbraucher, denen Druckmittel jeweils über eine Zumeßblende mit vorgeschalteter Druckwaage zufließt, die in Schließrichtung nur vom Druck vor der Zumeßblende und in Öffnungsrichtung nur vom Lastdruck des jeweiligen hydraulischen Verbrauchers und von einer Druckfeder beaufschlagt ist, erhält man keine lastunabhängige Durchflußverteilung. Man hat nur eine LS-Steuerung und einen LS-Verbraucher. Durch die DE 43 28 283 A1 ist nun eine Prioritätsschaltung zwischen einem LS-Verbraucher und einem oder mehreren LUDV-Verbrauchern geoffenbart, in der der LS-Verbraucher vorrangig mit Druckmittel versorgt wird. Es ist dazu ein Prioritätsventil vorgesehen, das einen mit einem Leitungsabschnitt stromauf der ersten Zumeßblende verbundenen, ersten Anschluß und einen mit der Lastmeldeleitung verbundenen zweiten Anschluß aufweist und dessen Ventilglied in Richtung Öffnen der Verbindung zwischen dem ersten Anschluß und dem zweiten Anschluß vom Lastdruck des vorrangigen hydraulischen Verbrauchers, also des LS-Verbrauchers, und einer Zusatzkraft beaufschlagbar ist. Das Prioritätsventil gemäß der Steuerung nach der DE 43 28 283 A1 wird in Richtung Schließen der Verbindung zwischen dem ersten Anschluß und dem zweiten Anschluß vom Druck im zweiten Anschluß beaufschlagt. Auf diese Weise wird zwar eine vorrangige Druckmittelversorgung des LS-Verbrauchers sichergestellt. Allerdings wird der Druck in der Zulaufleitung in bestimmten Fällen unnötig hoch, so daß Leistungsverluste entstehen. Ein solcher Fall liegt z.B. vor, wenn der Lastdruck des vorrangigen hydraulischen Verbrauchers höher als der Lastdruck des nachrangigen hydraulischen Verbrauchers ist. Dann wird in der Lastmeldeleitung ein um eine der auf das Ventilglied des Prioritätsventils wirkenden Zusatzkraft äquivalente Druckdifferenz über dem Lastdruck des vorrangigen hydraulischen Verbrauchers liegender Druck aufgebaut. Die Regelung der Bydropumpe wiederum bewirkt einen um ein bestimmtes Δp über dem Druck in der Lastmeldeleitung liegenden Druck in der Zulaufleitung, so daß letzterer Druck um mehr als das Regel-Δp am Regelorgan der Hydropumpe über dem Lastdruck des vorrangigen hydraulischen Verbrauchers liegt.For several hydraulic consumers, each with pressure medium flows through a metering orifice with an upstream pressure compensator, in the closing direction only from the pressure in front of the orifice and in Opening direction only from the load pressure of the respective hydraulic Consumer and is acted upon by a compression spring receives there is no load-independent flow distribution. You only have one LS control and a LS consumer. By DE 43 28 283 A1 is now a priority circuit between an LS consumer and one or more LUDV consumers, in which the LS consumer is primarily supplied with pressure medium. It For this purpose, a priority valve is provided, one with a Line section connected upstream of the first metering orifice, first connection and one connected to the load signaling line has second connection and its valve member in the direction Open the connection between the first port and the second Connection of the load pressure of the primary hydraulic consumer, So the LS consumer, and an additional force can be applied is. The priority valve according to the control DE 43 28 283 A1 is towards closing the connection between the first port and the second port of pressure acted on in the second connection. In this way, a priority supply of pressure medium to the LS consumer ensured. However, the pressure in the supply line is determined in certain Cases unnecessarily high, so that there is a loss of performance. Such a case is e.g. before when the load pressure of the priority hydraulic consumer higher than the load pressure of the subordinate hydraulic consumer. Then in the load signaling line to one of the on the valve member of the Priority valve acting additional force equivalent pressure difference above the load pressure of the primary hydraulic consumer horizontal pressure built up. The regulation of the Bydropump in turn causes a certain Δp above the pressure in pressure in the feed line, see that the latter pressure by more than the regulating Δp on the regulating element Hydraulic pump above the load pressure of the primary hydraulic consumer lies.

Während durch die DE 43 28 283 A1 eine Vorrangsteuerung zwischen einem LS-Verbraucher und einem LUDV-Verbraucher geoffenbar ist, zeigt die DE 35 07 122 C2 eine Vorrangsteuerung zwischen zwei LS-Verbrauchern. Diesen beiden hydraulischen Verbrauchern fließt also Druckmittelmenge jeweils über eine Zumeßblende und eine dieser Zumeßblende vorgeschaltete Druckwaage zu, die in Schließrichtung vom Druck vor der Zumeßblende beaufschlagt wird. Die Druckwaage, die dem vorrangigen hydraulischen Verbraucher zugeordnet ist, wird in Öffnungsrichtung vom Lastdruck dieses hydraulischen Verbrauchers und von einer Druckfeder beaufschlagt. Die Druckwaage für den nachrangigen hydraulischen Verbraucher wird in Schließrichtung ebenfalls von einer Druckfeder und außerdem von einem Druck beaufschlagt, der zwischen einer Festdrossel und einer als Prioritätsventil dienenden Proportionalblende abgegriffen wird, die zwischen die Festdrossel und einer Tankleitung geschaltet ist und die von der Druckdifferenz an der Zumeßblende des vorrangigen hydraulischen Verbrauchers gesteuert wird. Bei Untersättigung, also bei nicht ausreichend geförderter Druckmittelmenge verringert sich die Druckdifferenz an der Zumeßblende des vorrangig mit Druckmittel zu bedienenden hydraulischen Verbrauchers, so daß die Proportionalblende etwas öffnet, der Druck zwischen ihr und der Festdrossel etwas absinkt und die Druckwaage des nachrangig mit Druckmittel zu bedienenden hydraulischen Verbrauchers so weit schließt, daß für den vorrangigen hydraulischen Verbraucher wieder ausreichend Druckmittel zur Verfügung steht.While by DE 43 28 283 A1 priority control between an LS consumer and a LUDV consumer is disclosed, DE 35 07 122 C2 shows a priority control between two LS-consumers. These two hydraulic consumers are flowing So pressure medium amount each via an orifice and this metering orifice upstream pressure compensator in the closing direction is acted upon by the pressure in front of the metering orifice. The Pressure compensator assigned to the primary hydraulic consumer is in the opening direction from the load pressure of this hydraulic Consumer and acted upon by a compression spring. The pressure compensator for the subordinate hydraulic consumer is also in the closing direction by a compression spring and also pressurized between a fixed throttle and a proportional orifice serving as a priority valve is tapped between the fixed choke and one Tank line is switched and from the pressure difference on the metering orifice of the primary hydraulic consumer controlled becomes. In the event of undersaturation, i.e. inadequately funded The quantity of pressure medium reduces the pressure difference the metering orifice of the hydraulic to be operated primarily with pressure medium Consumer, so the proportional aperture is something opens, the pressure between her and the fixed throttle drops a little and the pressure balance of the subordinate to be operated with pressure medium hydraulic consumer closes so far that for the priority hydraulic consumers again sufficient pressure medium is available.

Ziel der Erfindung ist es, einen hydraulischen Steuerkreis, der die Merkmale aus dem Oberbegriff des Anspruchs 1 aufweist, mit dem also ein LS-Verbraucher gegenüber einem oder mehreren LUDV-Verbrauchern vorrangig mit Druckmittel versorgt werden soll, so weiterzuentwickeln, daß im Betrieb übermäßig hohe Leistungsverluste vermieden werden.The aim of the invention is to provide a hydraulic control circuit has the features from the preamble of claim 1 with which is an LS consumer versus one or more LUDV consumers should be primarily supplied with pressure medium, so to develop that excessively high power losses in operation be avoided.

Dieses Ziel wird bei einem hydraulischen Steuerkreis mit den Merkmalen aus dem Oberbegriff des Anspruchs 1 erfindungsgemäß dadurch erreicht, daß gemäß dem kennzeichnenden Teil des Anspruchs 1 das Ventilglied des Prioritätsventils in Richtung Schließen der Verbindung zwischen dem ersten Anschluß und dem zweiten Anschluß von einem in einem Leitungsabschnitt stromauf der ersten Zumeßblende herrschenden Druck beaufschlagbar ist. Bei dieser überraschend einfachen Lösung des Problems wird die Lastmeldeleitung dann, wenn der Lastdruck des LS-Verbrauchers höher als der Lastdruck eines parallel betätigten LUDV-Verbrauchers ist, mit dem Lastdruck des LS-Verbrauchers und nicht mit einem höheren Druck beaufschlagt. Deshalb wird auch in der Zulaufleitung nur ein Druck aufgebaut, der um das Regel-Δp an der Hydropumpe über dem Lastdruck des LS-Verbrauchers liegt. Ist der Lastdruck des LS-Verbrauchers niedriger als der Lastdruck eines parallel betätigten LUDV-Verbrauchers, so steht in der Lastmeldeleitung der Lastdruck des LUDV-Verbrauchers bzw. der höchste Lastdruck mehrerer gleichzeitig betätigter LUDV-Verbraucher an.This goal is achieved with a hydraulic control circuit Features from the preamble of claim 1 according to the invention achieved in that according to the characterizing part of the claim 1 the valve member of the priority valve in the direction Closing the connection between the first port and the second connection of one upstream in a line section the first metering orifice prevailing pressure can be applied. With this surprisingly simple solution to the problem, the Load signaling line when the load pressure of the LS consumer higher than the load pressure of a LUDV consumer operated in parallel with the load pressure of the LS consumer and not pressurized. Therefore also in the supply line only builds up a pressure that is around the control Δp on the hydraulic pump is above the load pressure of the LS consumer. If the load pressure of the LS consumer is lower than that Load pressure of a LUDV consumer operated in parallel, so it says the load pressure of the LUDV consumer or the highest load pressure of several LUDV consumers operated simultaneously on.

Vorteilhafte Ausgestaltungen eines erfindungsgemäßen hydraulischen Steuerkreises kann man den Unteransprüchen entnehmen.Advantageous configurations of a hydraulic system according to the invention Control circuit can be found in the subclaims.

So wird gemäß Anspruch 2 die in Richtung Öffnen der Verbindung zwischen dem ersten Anschluß und dem zweiten Anschluß auf das Ventilglied des Prioritätsventils wirkende Zusatzkraft vorteilhafterweise durch eine Feder erzeugt.So is according to claim 2 in the direction of opening the connection between the first port and the second port on the Valve element of the priority valve advantageously acting additional force generated by a spring.

Für eine schwingungsunanfällige Regelung erscheint es günstig, wenn gemäß Anspruch 3 das Prioritätsventil als Proportionalventil ausgebildet ist.For a vibration-insensitive regulation, it seems favorable if according to claim 3, the priority valve as a proportional valve is trained.

Vom Prioritätsventil wird die Druckdifferenz an der ersten Zumeßblende abgefühlt. Da im Falle einer Untersättigung die der ersten Zumeßblende vorgeschaltete Druckwaage ganz offen ist, kann ein Steuerraum am Ventilglied des Prioritätsventils gemäß Anspruch 4 stromauf der ersten Druckwaage mit der Zulaufleitung verbunden sein. Dies kann vorteilhaft im Hinblick auf die konstruktive Gestaltung der einzelnen Komponenten der Steuerung sein. In konstruktiver Hinsicht mag es auch von Vorteil sein, wenn gemäß Anspruch 5 ein Steuerdruckraum am Ventilglied des Prioritätsventils und der erste Anschluß des Prioritätsventils auf derselben Seite der ersten Druckwaage mit dem Zulauf zur ersten Zumeßblende verbunden sind.The pressure difference at the first orifice is from the priority valve sensed. Since in the event of undersaturation the the first metering orifice upstream of the pressure compensator is completely open, can a control room on the valve member of the priority valve according to Claim 4 upstream of the first pressure compensator with the feed line be connected. This can be advantageous in terms of construction Design of the individual components of the control his. In terms of construction, it may also be an advantage if according to claim 5 a control pressure chamber on the valve member of the Priority valve and the first connection of the priority valve on the same side of the first pressure compensator with the inlet to the first Orifice plate are connected.

Gemäß Anspruch 6 ist eine Bypass-Leitung um das Prioritätsventil herum vorgesehen, die eine Stromstelle stromab der ersten Zumeßblende mit der Lastmeldeleitung verbindet und in der ein zur Lastmeldeleitung hin öffnendes Rückschlagventil angeordnet ist. Auf diese Weise wird erreicht, daß, sofern der LS-Verbraucher lastführend ist, also den höchsten Lastdruck aufweist, dieser Lastdruck in der Lastmeldeleitung herrscht und bei ausreichender Druckmittelmenge für alle betätigten Verbraucher die Druckdifferenz über die erste Zumeßblende von der vorgeschalteten Druckwaage bestimmt wird. Nur bei Untersättigung wird die Druckdifferenz durch die Zusatzkraft am Prioritätsventil bestimmt, zu der normalerweise eine kleinere Druckdifferenz äquivalent ist als der Federkraft an der ersten Druckwaage. Durch eine Ausbildung gemäß Anspruch 7 wird verhindert, daß aus der Lastmeldeleitung Druckmittel in die Zulauf leitung fließt, wenn von der Hydropumpe noch kein Druck aufgebaut ist. According to claim 6 is a bypass line around the priority valve provided around that a current point downstream of the first metering orifice connects to the load reporting line and in the one to Check valve opening check valve is arranged. In this way it is achieved that, provided the LS consumer is load-bearing, i.e. has the highest load pressure, this Load pressure prevails in the load reporting line and if sufficient Pressure medium quantity for all actuated consumers the pressure difference via the first metering orifice from the upstream pressure compensator is determined. The pressure difference is only when there is undersaturation determined by the additional force on the priority valve to which a smaller pressure differential is usually equivalent to the spring force on the first pressure compensator. Through training according to claim 7 is prevented from the load reporting line Pressure medium flows into the inlet line when from the hydraulic pump no pressure has been built up yet.

Mehrere Ausführungsbeispiele eines erfindungsgemäßen hydraulischen Steuerkreises sind in den Zeichnungen dargestellt. Anhand der Figuren dieser Zeichnungen wird die Erfindung nun näher erläutert.Several embodiments of a hydraulic according to the invention Control circuit are shown in the drawings. Based The figures of these drawings, the invention will now be explained in more detail.

Es zeigen

Figur 1
ein erstes Ausführungsbeispiel, bei dem der erste Anschluß und ein Steuerraum des Prioritätsventils gemeinsam stromauf der dem vorrangigen hydraulischen Verbraucher zugeordneten Druckwaage mit dem Zulauf verbunden sind,
Figur 2
ein zweites Ausführungsbeispiel, bei dem der erste Anschluß und ein Steuerraum des Prioritätsventils stromab der Druckwaage mit dem Zulauf verbunden sind,
Figur 3
ein drittes Ausführungsbeispiel, das eine Bypass-Leitung um das Prioritätsventil aufweist, und
Figur 4
das Schaltbild einer Verstellpumpe einschließlich Regelventilen, wie sie in den Ausführungsbeispielen nach den Figuren 1 bis 3 verwendbar ist.
Show it
Figure 1
a first embodiment in which the first connection and a control chamber of the priority valve are connected to the inlet together upstream of the pressure compensator assigned to the priority hydraulic consumer,
Figure 2
a second embodiment in which the first connection and a control chamber of the priority valve are connected to the inlet downstream of the pressure compensator,
Figure 3
a third embodiment, which has a bypass line around the priority valve, and
Figure 4
the circuit diagram of a variable pump including control valves, as it can be used in the embodiments of Figures 1 to 3.

Nach Figur 1 saugt eine Verstellpumpe 10 mit einer Verstellung 11 Druckmittel aus einem Tank 12 an und gibt es in ein System von Zuleitungen 13 ab. Über die Zuleitungen werden ein erster hydraulischer Verbraucher 14, der als Gleichgangzylinder ausgebildet ist, und zumindest ein zweiter hydraulischer Verbraucher 15, der ein Differentialzylinder ist, mit Druckmittel versorgt. Die Richtung und die Geschwindigkeit des Gleichgangzylinders 14 wird durch eine entsprechende Betätigung eines 4/3-Proportional-Wegeventils 16 bestimmt, dessen Ventilschieber in einer Mittelstellung federzentriert ist, in der die vier Arbeitsanschlüsse und ein Steueranschluß 18 des Wegeventils 16 gesperrt sind. Bei einer Verschiebung des Ventilschiebers aus seiner Mittelstellung heraus in die eine oder in die andere Richtung wird eine Zumeßblende 17 je nach dem Weg, den der Ventilschieber bewegt wird, unterschiedlich weit aufgemacht. Der Steueranschluß 18 wird stromab der Zumeßblende mit dem Vorlauf zum Gleichgangzylinder 14 verbunden.According to Figure 1, a variable displacement pump 10 sucks with an adjustment 11 pressure medium from a tank 12 and there is in a system from leads 13. A first is via the supply lines hydraulic consumer 14, which is designed as a synchronous cylinder is, and at least a second hydraulic consumer 15, which is a differential cylinder, supplied with pressure medium. The direction and speed of the synchronous cylinder 14 by a corresponding actuation of a 4/3 proportional directional valve 16 determines whose valve spool is in a central position is spring-centered, in which the four working connections and a control connection 18 of the directional control valve 16 are blocked. at a displacement of the valve spool from its central position out in one direction or the other becomes a metering orifice 17 depending on the way the valve spool is moved, opened differently. The control terminal 18 is downstream of the metering orifice with the flow to the synchronous cylinder 14 connected.

Zwischen das System der Zuleitungen 13 und einen Zulaufanschluß 19 des Wegeventils 16 ist eine 2-Wege-Druckwaage 20 eingefügt, deren Regelkolben in Richtung Schließen vom Druck stromauf einer Zumeßblende 17 und in Richtung Öffnen über eine Steuerleitung 61 vom Druck im Steueranschluß 18 des Wegeventils 16, also vom Lastdruck des Gleichgangzylinders 14, und von einer Regelfeder 21 beaufschlagt wird. Die Kraft der Regelfeder 21 ist so ausgelegt, daß ihr eine Druckdifferenz von z.B. 15 bar über eine Zumeßblende 17 äquivalent ist.Between the system of supply lines 13 and an inlet connection 19 of the directional control valve 16, a 2-way pressure compensator 20 is inserted, whose control piston in the direction of closing the pressure upstream Metering orifice 17 and in the direction of opening via a control line 61 from the pressure in the control port 18 of the directional control valve 16, that is from Load pressure of the synchronous cylinder 14, and from a control spring 21 is applied. The force of the control spring 21 is designed that you have a pressure difference of e.g. 15 bar via an orifice 17 is equivalent.

Während somit die dem ersten hydraulischen Verbraucher 14 zugeordnete erste Druckwaage 20 der ersten Zumeßblende 17 vorgeschaltet ist, ist die dem zweiten hydraulischen Verbraucher 15 zugeordnete zweite Druckwaage 30 einer zweiten Zumeßblende 31 nachgeschaltet. Für die Richtungssteuerung des Differentialzylinders 15 ist zwischen der zweiten Druckwaage 30 und dem Differentialzylinder ein Wegeventil 32 angeordnet, über das im Vergleich zum Druckabfall an der Zumeßblende 31 kein nennenswerter Druckabfall mehr auftritt, wenn der Differentialzylinder 15 betätigt wird. Die Zumeßblende 31 und die zur Richtungssteuerung notwendigen Steuernuten sind in bekannter Weise am selben Ventilschieber ausgebildet, so daß Richtungs- und Geschwindigkeitssteuerung jeweils ohne weiteres gemeinsam vonstatten gehen. Der Regelkolben 33 der Druckwaage 30 wird vorne in Richtung Öffnen der Verbindung zwischen der Zumeßblende 31 und dem Wegeventil 32 vom Druck nach der Zumeßblende und rückwärtig in Richtung Schließen der Verbindung von einem in einem Steuerdruckraum 34 herrschenden Steuerdruck und von einer schwachen Druckfeder 35, der ein Druck von z.B. lediglich 0,5 bar äquivalent ist, beaufschlagt. Die Vorderseite des Regelkolbens 33 ist über einen im Regelkolben verlaufenden Kanal 36 mit dem Steuerdruckraum 34 verbunden, wobei in dem Kanal 36 ein zum Steuerdruckraum hin öffnendes Rückschlagventil 37 angeordnet ist. Thus, the one associated with the first hydraulic consumer 14 first pressure compensator 20 upstream of the first orifice 17 is the second hydraulic consumer 15th assigned second pressure compensator 30 to a second metering orifice 31 downstream. For the direction control of the differential cylinder 15 is between the second pressure compensator 30 and the differential cylinder a directional control valve 32 is arranged, in comparison for the pressure drop at the metering orifice 31, no significant Pressure drop occurs more when the differential cylinder 15 is actuated becomes. The metering orifice 31 and that for direction control necessary control grooves are in a known manner on the same valve spool trained so that direction and speed control go together without further ado. The Control piston 33 of the pressure compensator 30 is opened towards the front the connection between the metering orifice 31 and the directional control valve 32 from the pressure after the metering orifice and backwards in the direction Closing the connection of one in a control pressure chamber 34 prevailing control pressure and a weak compression spring 35, which is a pressure of e.g. is equivalent to only 0.5 bar. The front of the control piston 33 is in a Control piston extending channel 36 with the control pressure chamber 34 connected, one in the channel 36 to the control pressure chamber opening check valve 37 is arranged.

Parallel zu der Zumeßblende 31, der Druckwaage 30 und dem Wegeventil 32 für den zweiten hydraulischen Verbraucher 15 können weitere zumeßblenden, Druckwaagen und Wegeventile für weitere hydraulische Verbraucher an das System der Zuleitungen 13 angeschlossen sein. Dabei sind die Steuerdruckräume 34 aller Druckwaagen 30 miteinander verbunden, so daß in diesen Steuerdruckräumen derselbe Druck ansteht. Die Regelkolben 33 der Druckwaagen suchen sich bei einer Betätigung eines zweiten hydraulischen Verbrauchers in eine solche Stellung zu bringen, in der sich an ihrer Vorderseite ein lediglich um die der Kraft der Druckfeder 35 äquivalente Druckdifferenz höherer Druck einstellt als in den Steuerdruckräumen 34.Parallel to the metering orifice 31, the pressure compensator 30 and the directional control valve 32 for the second hydraulic consumer 15 can additional metering orifices, pressure compensators and directional valves for others hydraulic consumers connected to the system of the feed lines 13 his. The control pressure chambers 34 are all pressure compensators 30 connected to each other, so that in these control pressure rooms the same pressure is applied. The control pistons 33 of the pressure compensators look for themselves when actuating a second hydraulic To bring the consumer into such a position in which to their front one only around that of the force of the compression spring 35 equivalent pressure difference sets higher pressure than in the Control pressure rooms 34.

Über die Kanäle 36 und die Rückschlagventile 37 wird, läßt man einmal den ersten hydraulischen Verbraucher 14 völlig außer acht, jeweils der höchste Lastdruck aller betätigten zweiten hydraulischen Verbraucher 15 in die Steuerdruckräume 34 gegeben.About the channels 36 and the check valve 37 is allowed once completely the first hydraulic consumer 14 eight, the highest load pressure of all actuated second hydraulic Given consumers 15 in the control pressure rooms 34.

Die Steuerdruckräume 34 sind an eine Lastmeldeleitung 38 angeschlossen, die zur Verstellung 11 der Pumpe 10 führt. Insbesondere führt, wie dies aus Figur 4 ersichtlich ist, die Lastmeldeleitung 38 zu einem Regelventil 39 mit drei Anschlüssen, von denen einer mit einem Stellzylinder 40 der Verstellpumpe 10 verbunden ist. Ein weiterer Anschluß des Regelventils 39 ist mit einer Zuleitung 13 und der dritte Anschluß mit Tank 12 verbunden. Der Regelkolben des Regelventils 39 wird in Richtung einer Verbindung des ersten Anschlusses mit dem zweiten Anschluß vom Druck in der Zuleitung 13 und in Richtung einer Verbindung des ersten Anschlusses mit dem dritten Anschluß vom Druck in der Lastmeldeleitung 38 und von einer Regelfeder 41 beaufschlagt. Verstellpumpen und Regelventile gemäß dem Schaltbild nach Figur 4 sind allgemein bekannt und auf dem Markt ohne weiteres erhältlich. Es erübrigt sich deshalb, näher darauf einzugehen. Es sei lediglich darauf hingewiesen, daß die Pumpenregelung bewirkt, daß sich in der Zuleitung 13 ein Druck einstellt, der um eine der Kraft der Regelfeder 41 äquivalente Druckdifferenz über dem Druck in der Lastmeldeleitung 38 liegt. Die Druckdifferenz betrage z.B. 20 bar, ist also höher als die der Kraft der Regelfeder 21 der ersten Druckwaage 20 äquivalente Druckdifferenz von 15 bar.The control pressure chambers 34 are connected to a load signaling line 38, which leads to the adjustment 11 of the pump 10. In particular leads, as can be seen from Figure 4, the load reporting line 38 to a control valve 39 with three connections, one of which one connected to an actuating cylinder 40 of the variable displacement pump 10 is. Another connection of the control valve 39 is with a supply line 13 and the third connection to tank 12. The control piston of the control valve 39 is in the direction of Connection of the first connection with the second connection from Pressure in the supply line 13 and in the direction of a connection of the first connection with the third connection from the pressure in the Load signaling line 38 and acted upon by a control spring 41. Variable pumps and control valves according to the circuit diagram according to the figure 4 are generally known and readily available on the market. It is therefore unnecessary to go into this in more detail. It is just pointed out that the pump control causes that a pressure is established in the feed line 13, which is around a the force of the control spring 41 equivalent pressure difference over the Pressure in the load reporting line 38 is. The pressure difference is e.g. 20 bar, is therefore higher than the force of the control spring 21 of the first pressure compensator 20 equivalent pressure difference of 15 bar.

Der erste hydraulische Verbraucher 14 soll vorrangig vor dem zweitem hydraulischen Verbraucher 15 mit Druckmittel versorgt werden. Dafür ist ein Prioritätsventil 45 vorgesehen, das als Proportionalblende mit einem Eingang 46 und einem Ausgang 47 ausgebildet ist. Letzterer ist mit der Lastmeldeleitung 38 verbunden. Der Eingang 46 ist stromauf der Druckwaage 20 mit einer Zuleitung 13 verbunden. Das Ventilglied 48 des Prioritätsventils wird in Richtung Schließen der Verbindung zwischen dem Eingang und dem Ausgang von einem in einem mit einer Zuleitung 13 verbundenen ersten Steuerdruckraum 49 herrschenden Druck und in Richtung Öffnen der Verbindung von einem in einem zweiten Steuerdruckraum herrschenden Druck und einer Regelfeder 51 beaufschlagt. Der zweite Steuerdruckraum 50 wird bei einer Betätigung des Wegeventils 16 über die Steuerleitung 61 mit einer Stelle stromab einer Zumeßblende 17 verbunden. In ihm herrscht dann der Lastdruck des ersten hydraulischen Verbrauchers 14. Die Regelfeder 51 ist z.B. so ausgelegt, daß am Ventilglied 48 des Prioritätsventils 45 ein Kräftegleichgewicht besteht, wenn der Druck im ersten Steuerdruckraum 49 um 13 bar höher als der Druck im zweiten Steuerdruckraum 50 ist. Diese Druckdifferenz ist niedriger als die der Kraft der Regelfeder 21 der Druckwaage 20 äquivalente Druckdifferenz.The first hydraulic consumer 14 is to take priority over the second hydraulic consumer 15 supplied with pressure medium become. For this purpose, a priority valve 45 is provided, which as Proportional diaphragm with an input 46 and an output 47 is trained. The latter is connected to the load signaling line 38. The input 46 is upstream of the pressure compensator 20 with a Lead 13 connected. The valve member 48 of the priority valve will close towards the connection between the entrance and the output of one in one connected to a feed line 13 first control pressure chamber 49 prevailing pressure and in Direction of opening the connection from one in a second control pressure chamber prevailing pressure and a control spring 51 applied. The second control pressure chamber 50 is activated of the directional control valve 16 via the control line 61 with one point connected downstream of an orifice 17. Then it reigns in him Load pressure of the first hydraulic consumer 14. The control spring 51 is e.g. designed so that the valve member 48 of the priority valve 45 there is a balance of forces when the pressure in the first control pressure chamber 49 by 13 bar higher than the pressure in second control pressure chamber 50. This pressure difference is lower than that of the force of the control spring 21 of the pressure compensator 20 equivalent Pressure difference.

Der erste hydraulische Verbraucher 14, der vorrangig mit Druckmittel zu bedienen ist, wird, ohne daß das Prioritätsventil 45 in Funktion zu treten hätte, immer dann ausreichend mit Druckmittel versorgt, wenn die Summe seines Lastdruckes plus des Regel-Δp der Verstellung 11 an der Verstellpumpe 10 kleiner ist als der höchste Lastdruck aller gleichzeitg mitbetätigten zweiten hydraulischen Verbraucher 15. Denn Druckmittel fließt immer dem hydraulischen Verbraucher mit dem geringsten Lastdruck zu.The first hydraulic consumer 14, primarily with pressure medium is to be operated without the priority valve 45 would have to come into operation, always with sufficient pressure medium supplied when the sum of its load pressure plus the control Δp the adjustment 11 on the variable displacement pump 10 is smaller than the highest load pressure of all simultaneously operated second hydraulic consumer 15. Because pressure medium always flows to the hydraulic consumer with the lowest load pressure.

Es sei nun der Fall betrachtet, daß der Lastdruck des ersten hydraulischen Verbrauchers 14 höher als der höchste Lastdruck aller gleichzeitig betätigten zweiten hydraulischen Verbraucher 15 ist. Er betrage z.B. 80 bar, während der höchste Lastdruck der LUDV-Verbraucher 60 bar sei. Bei einer Betätigung des Wegeventils 16 stehen dann im Steuerdruckraum 50 des Prioritätsventils 45 80 bar an. Mit den 13 bar der Regelfeder 51 wirken 93 bar in Öffnungsrichtung des Proportionalventils 45. Am Regelkolben dieses Ventils stellt sich ein Gleichgewicht der Kräfte dann ein, wenn im ersten Steuerdruckraum 49 93 bar anstehen. Weil diese 93 bar um das Regel-Δp des Pumpenregelventils 39 höher sind als der Druck in der Lastmeldeleitung 38, herrscht in der Lastmeldeleitung 38 entsprechend dem Regel-Δ der Verstellpumpe 10 in Höhe von 20 bar ein Druck von 73 bar. Dieser Druck steht auch in den Steuerräumen 34 der Druckwaagen 30 an. Deren Zumeßblenden 31 seien noch geschlossen. Da nun der Druck in dem System der Zuleitungen 13 nur um 13 bar über dem Lastdruck des vorrangigen hydraulischen Verbrauchers 14 liegt, ist die Druckwaage 20 ganz offen und über die Zumeßblende 17 fallen nur 13 bar ab. Soll nun ein zweiter hydraulischer Verbraucher 15 betätigt werden, so wird die entsprechende Zumeßblende 31 geöffnet und das entsprechende Wegeventil 32 aus seiner Mittelstellung verschoben. Zwischen der Zumeßblende 31 und der nachgeschalteten Druckwaage 30 stellt sich, sieht man einmal von dem Einfluß der Druckfeder 35 ab, derselbe Druck wie im Steuerdruckraum 34, nämlich ein Druck in Höhe von 73 bar ein. Denn nur dann herrscht am Regelkolben 33 der Druckwaage 30 ein Kräftegleichgewicht. Da im System der Zuleitungen 13 der Druck bei 93 bar liegt, beträgt die Druckdifferenz über eine Zumeßblende 31 wie gewünscht 20 bar entsprechend dem Regel-Δp der Verstellpumpe 10.Now consider the case where the load pressure of the first hydraulic Consumer 14 higher than the highest load pressure of all simultaneously actuated second hydraulic consumer 15 is. It is e.g. 80 bar, while the highest load pressure is the LUDV consumer is 60 bar. When the directional valve is actuated 16 are then in the control pressure chamber 50 of the priority valve 45 to 80 bar. With the 13 bar of the control spring 51, 93 bar act in Proportional valve 45 opens in the direction of the control piston Valve then a balance of forces if there are 49 93 bar in the first control pressure chamber. Because this 93 bar by the control Δp of the pump control valve 39 are higher than that Pressure in the load signaling line 38 prevails in the load signaling line 38 corresponding to the control Δ of the variable displacement pump 10 in height from 20 bar a pressure of 73 bar. This pressure is also in the Control rooms 34 of the pressure compensators 30. Their metering orifices 31 are still closed. Now there is the pressure in the system of the supply lines 13 only by 13 bar above the load pressure of the priority hydraulic consumer 14 is, the pressure compensator 20 is complete open and via the metering orifice 17 drop only 13 bar. Should now a second hydraulic consumer 15 are operated, so the corresponding orifice 31 is opened and the corresponding Directional valve 32 shifted from its central position. Between the metering orifice 31 and the downstream pressure compensator 30 turns, one sees the influence of the compression spring 35th ab, the same pressure as in the control pressure chamber 34, namely a pressure in the amount of 73 bar. Because only then will there be control piston 33 the pressure compensator 30 a balance of forces. As in the supply system 13 the pressure is 93 bar, the pressure difference is via a metering orifice 31 corresponding to 20 bar as desired the control Δp of the variable displacement pump 10.

Wird nun durch Vergrößerung des Öffnungsquerschnitts einer Zumeßblende 17 oder durch Vergrößerung der Öffnungsquerschnitte von mehreren Zumeßblenden 31 immer mehr Druckmittelmenge von der Pumpe angefordert, so erreicht diese schließlich ihre maximale Verstellung, von der an die Druckmittelmenge nicht mehr vergrößert werden kann. Dies führt zu einer Verminderung des Druckes im System der Zuleitungen 13 und damit im ersten Steuerdruckraum 49 des Prioritätsventils 45. Dessen Regelkolben 48 wird in Richtung Öffnen der Verbindung zwischen den Anschlüssen 46 und 47 verschoben, so daß sich der Druck in der Lastmeldeleitung 38 und in den Steuerdruckräumen 34 der Druckwaagen 30 erhöht. Deren Regelkolben 33 erreichen wiederum einen Gleichgewichtszustand, wenn sich auch der Druck zwischen den Zumeßblenden 31 und den Druckwaagen 30 auf den Wert, den der Druck in den Steuerdruckräumen 34 hat, vergrößert. Die Druckdifferenz über die Zumeßblenden 31 ist nun kleiner als das Regel-Δp der Pumpe 10 in Höhe von 20 bar. Die über die Zumeßblenden 31 fließende Druckmittelmenge ist entsprechend verringert. Und zwar ist sie so stark verringert, daß im System der Zuleitungen 13 ein Druck von 93 bar erhalten bleibt. Denn nur dann herrscht am Regelkolben 48 des Prioritätsventils ein Kräftegleichgewicht. Während somit die Druckdifferenz über die Zumeßblenden 31 verkleinert ist, bleibt die Druckdifferenz in Höhe von 13 bar über die Zumeßblende 17 erhalten. Im Extremfall steigt der Druck in der Lastmeldeleitung 38 und in den Steuerdruckräumen 34 der Druckwaagen 30 bis auf 93 bar an, so daß kein Druckmittel mehr über die Zumeßblenden 31 fließt.Will now by enlarging the opening cross section of a metering orifice 17 or by enlarging the opening cross-sections of several orifice plates 31 more and more pressure medium from the When the pump is requested, it finally reaches its maximum Adjustment from which the amount of pressure medium no longer increases can be. This leads to a reduction in pressure in the system of the feed lines 13 and thus in the first control pressure chamber 49 of the priority valve 45. Its control piston 48 is in the direction Open the connection between ports 46 and 47 shifted so that the pressure in the load signaling line 38 and increased in the control pressure chambers 34 of the pressure compensators 30. Their control pistons 33 again reach a state of equilibrium, even if the pressure between the metering orifices 31 and Pressure compensators 30 to the value of the pressure in the control pressure chambers 34 has enlarged. The pressure difference across the metering orifices 31 is now smaller than the control Δp of the pump 10 in height of 20 bar. The amount of pressure medium flowing through the metering orifices 31 is reduced accordingly. And it is so strong reduces that in the system of the supply lines 13 a pressure of 93 cash remains. Because only then will there be control piston 48 a balance of forces in the priority valve. So while the pressure difference across the metering orifices 31 is reduced, the pressure difference of 13 bar remains above the metering orifice 17 received. In extreme cases, the pressure in the load reporting line increases 38 and in the control pressure chambers 34 of the pressure compensators 30 up to 93 bar, so that no pressure medium via the metering orifices 31 flows.

In dem geschilderten Fall der Untersättigung ist die dem vorrangigen hydraulischen Verbraucher 14 zugeordnete Druckwaage 20 ganz offen. Am Ausgang der Druckwaage herrscht deshalb derselbe Druck wie am Eingang und in dem System der Zuleitungen 13. Der erste Anschluß 46 des Prioritätsventils 45 sowie der Steuerdruckraum 49 können deshalb auch stromab der Druckwaage an den Zulauf zum Wegeventil 16 angeschlossen werden. Eine solche Ausführung ist in Figur 2 gezeigt. Im übrigen entspricht die Ausführung nach Figur 2 vollauf derjenigen nach Figur 1, so daß hinsichtlich ihres Aufbaus und ihrer Funktion auf die Beschreibung des ersten Ausführungsbeispiels verwiesen werden kann.In the described case of undersaturation, priority is given to that Hydraulic consumer 14 assigned pressure compensator 20 all open. The same therefore prevails at the outlet of the pressure compensator Pressure as at the entrance and in the system of supply lines 13. The first port 46 of the priority valve 45 and the control pressure chamber 49 can therefore also downstream of the pressure compensator Inlet to directional valve 16 can be connected. Such an execution is shown in Figure 2. Otherwise the execution corresponds according to Figure 2 fully that of Figure 1, so that with regard to their structure and their function on the description of the first embodiment can be referred.

Ergänzend sei lediglich zu beiden Ausführungen nach den Figuren 1 und 2 darauf hingewiesen, daß die Lastmeldeleitung 38 über einen Stromregler 55 mit Tank 12 verbunden ist. Über diesen Stromregler wird die Lastmeldeleitung 38 jeweils von Druck entlastet, wenn keiner der hydraulischen Verbraucher betätigt wird.Supplementary is only to both versions according to the figures 1 and 2 pointed out that the load signaling line 38 via a Current regulator 55 is connected to tank 12. About this current regulator the load signaling line 38 is relieved of pressure in each case, if none of the hydraulic consumers are actuated.

In Figur 3 sind lediglich das Prioritätsventil 45 sowie die Druckwaage 20 sowie verschiedene zu diesen beiden Ventilen hinführende und wegführende Druckmittelwege gezeigt, die sich zusammen mit den Ventilen in einem Gehäuse 60 befinden. Die Ausführung nach Figur 3 ist weitgehend gleich der Ausführung nach Figur 1 und kann ohne weiteres um die in Figur 1 zusätzlich gezeigten Komponenten ergänzt werden. Unterschiedlich zu der Ausführung nach Figur 1 ist, daß nun die Steuerleitung 61, über die der Steueranschluß 18 des Wegeventils 16 mit dem Steuerdruckraum 50 des Prioritätsventils 45 und mit einem Steuerdruckraum an der Druckwaage 20 verbunden ist, über ein sich in einer Bypass-Leitung 62 befindliches Rückschlagventil 63 auch mit der Lastmeldeleitung 38 verbunden ist. Dabei sperrt das Rückschlagventil 63 von der Lastmeldeleitung 38 zum Kanal 61, also zum Steueranschluß 18 des Wegeventils 16 hin.In Figure 3, only the priority valve 45 and the Pressure compensator 20 and various leading to these two valves and shown leading pressure medium paths that come together with the valves in a housing 60. Execution according to Figure 3 is largely the same as the embodiment Figure 1 and can easily by the additional shown in Figure 1 Components are added. Different from the execution according to Figure 1 is that now the control line 61, via the the control connection 18 of the directional control valve 16 with the control pressure chamber 50 of the priority valve 45 and with a control pressure chamber on the Pressure compensator 20 is connected via itself in a bypass line 62 located check valve 63 also with the Load reporting line 38 is connected. The check valve closes 63 from the load signaling line 38 to the channel 61, that is to say Control connection 18 of the directional valve 16 out.

Desweiteren ist auch zwischen dem zweiten Anschluß 47 des Prioritätsventils 45 und der Lastmeldeleitung 38 ein Rückschlagventil 64 angeordnet. Dieses sperrt zum Anschluß 47 hin.Furthermore, there is also between the second connection 47 of the priority valve 45 and the load signaling line 38 a check valve 64 arranged. This blocks to connection 47.

Bei der Ausführung nach Figur 1 bestimmt die Regelfeder 51 des Prioritätsventils 45 den Druckabfall an einer Zumeßblende 17 auch bei in genügendem Maße geförderter Druckmittelmenge, wenn der Lastdruck des vorrangig zu bedienenden hydraulischen Verbrauchers 14 minus die Differenz zwischen dem der Kraft der Regelfeder 41 des Regelventils 39 äquivalenten Druck und dem der Kraft der Regelfeder 51 des Prioritätsventils 45 äquivalenten Druck größer ist als der höchste Lastdruck aller betätigten LUDV-Verbraucher 15. Denn dann wird in der Lastmeldeleitung 38 über das Prioritätsventil 45 ein Druck eingeregelt, der um die Differenz zwischen dem Äquivalenzdruck der Regelfeder 41 und dem Äquivalenzdruck der Regelfeder 51 unterhalb des Lastdrucks des vorrangig zu bedienenden hydraulischen Verbrauchers 14 liegt, also z.B. bei einem Lastdruck von 80 bar, einem Äquivalenzdruck der Regelfeder 41 von 20 bar und einem Äquivalenzdruck der Regelfeder 51 in Höhe von 13 bar 73 bar beträgt. Bei Untersättigung steigt der Druck in der Lastmeldeleitung 38 über diesen Wert an.In the embodiment according to FIG. 1, the control spring 51 determines the Priority valve 45 the pressure drop at an orifice 17 even if the amount of pressure medium delivered is sufficient, if the load pressure of the hydraulic consumer to be operated as a priority 14 minus the difference between that of the force of the control spring 41 of the control valve 39 equivalent pressure and that of Force of the control spring 51 of the priority valve 45 equivalent Pressure is greater than the highest load pressure of all actuated LUDV consumer 15. Because then 38 in the load reporting line Via the priority valve 45, a pressure is regulated, which is around the Difference between the equivalent pressure of the control spring 41 and the Equivalent pressure of the control spring 51 below the load pressure of the priority hydraulic user 14 is located, e.g. e.g. at a load pressure of 80 bar, an equivalent pressure the control spring 41 of 20 bar and an equivalent pressure of the control spring 51 in the amount of 13 bar is 73 bar. In case of undersaturation the pressure in the load signaling line 38 rises above it Value.

Bei der Ausführung nach Figur 3 wird bei ausreichend geförderter Druckmittelmenge und lastführendem vorrangigen hydraulischen Verbraucher 14 der Lastdruck dieses hydraulischen Verbrauchers über das Rückschlagventil 63 in die Lastmeldeleitung 38 geleitet. Der Druck im System der Zuleitungen 13 liegt also um den Äquivalenzdruck der Regelfeder 41, also um das Regel-Δp der Verstellpumpe 10 über dem Lastdruck des hydraulischen Verbrauchers 14, beträgt also bei einem Lastdruck von z.B. 80 bar und einem Regel-Δp von z.B. 20 bar 100 bar. Der-Druckabfall über eine Zumeßblende 17 wird dann wie im Fall eines lastführenden zweiten Verbrauchers 15 von der Kraft der Regelfeder 21 der Druckwaage 20 bestimmt. Erst wenn bei Untersättigung der Druck im System der Zuleitungen 13 auf die Summe aus dem Lastdruck des hydraulischen Verbrauchers 14 plus dem zur Kraft der Regelfeder 51 des Prioritätsventils 45 äquivalenten Druck, also z.B. auf 80 bar plus 13 bar gleich 93 bar abgefallen ist, beträgt der Druckabfall über eine Zumeßblende 17 des Wegeventils 16 13 bar, ist also durch die Kraft der Regelfeder 51 bestimmt. Eine weitere Verkleinerung des Druckabfalls über eine Zumeßblende 17 tritt nicht auf, weil bei weiter zunehmender Untersättigung der Druck in der Lastmeldeleitung 38 über das Prioritätsventil 45 erhöht und dadurch die Druckwaagen 30 der LUDV-Verbraucher in Schließrichtung verstellt werden. In the embodiment according to FIG. 3, the funding is sufficient Pressure medium quantity and load-bearing priority hydraulic Consumer 14 the load pressure of this hydraulic consumer passed via the check valve 63 into the load signaling line 38. The pressure in the system of the feed lines 13 is thus around Equivalent pressure of the control spring 41, that is, the control Δp of the variable displacement pump 10 above the load pressure of the hydraulic consumer 14, i.e. at a load pressure of e.g. 80 bar and one Control Δp of e.g. 20 bar 100 bar. The pressure drop over a metering orifice 17 then becomes as in the case of a load-carrying second Consumer 15 of the force of the control spring 21 of the pressure compensator 20 determined. Only if the pressure in the system occurs when there is insufficient saturation of the feed lines 13 to the sum of the load pressure of the hydraulic Consumer 14 plus the force of the control spring 51 des Priority valve 45 equivalent pressure, e.g. to 80 bar plus 13 bar has dropped to 93 bar, the pressure drop is via a metering orifice 17 of the directional control valve 16 is 13 bar determined by the force of the control spring 51. Another downsizing the pressure drop across an orifice 17 does not occur because the pressure in the Load reporting line 38 increased via the priority valve 45 and thereby the pressure compensators 30 of the LUDV consumers in the closing direction be adjusted.

Das Rückschlagventil 64 verhindert einen Druckmittelfluß vom hydraulischen Verbraucher 14 über das Rückschlagventil 63 in das System der Zuleitungen 13, sofern z.B. bei Beginn einer Betätigung der Druck in den Zuleitungen noch nicht über dem Lastdruck liegt.The check valve 64 prevents a pressure medium flow from the hydraulic Consumer 14 via the check valve 63 in that System of supply lines 13, if e.g. at the start of an operation the pressure in the supply lines is not yet above the load pressure lies.

Claims (7)

  1. Hydraulic control circuit for a primary first hydraulic consumer (14) and for a secondary second hydraulic consumer (15),
    with a first metering diaphragm (17), via which pressure medium can be supplied to the first hydraulic consumer (14) and via which a constant pressure difference can be set by means of a preceding pressure compensator (20),
    with a second metering diaphragm (31), via which pressure medium can be supplied to the second hydraulic consumer (15) and which is followed by a second pressure compensator (30) which can be acted upon in the closing direction by a control pressure prevailing in a rear control chamber (34) and in the opening direction by the pressure downstream of the second metering diaphragm (31),
    with a pressure medium source (10) of variable delivery quantity, which can be controlled as a function of the highest load pressure of the actuated hydraulic consumers (14, 15) in such a way that the pressure in an inflow line (13) lies above the highest load pressure by the amount of a specific pressure difference,
    with a load signaling line (38) which can be acted upon by the load pressure of the second hydraulic consumer (15) or by a pressure derived therefrom and which is connected to the rear control chamber (34) of the second pressure compensator (30) and to a regulating member (11) of the pressure medium source (10),
    and with a priority valve (45) which has a first port (46), connected to a line section (13) upstream of the first metering diaphragm (17), and a second port (47), connected to the load signaling line (38), and the valve member (48) of which can be acted upon, in the direction of the opening of the connection between the first port (46) and the second port (47), by the load pressure of the primary hydraulic consumer (14) and by an additional force (51), characterized in that the valve member (48) of the priority valve (45) can be acted upon, in the direction of the closing of the connection between the first port (46) and the second port (47), by a pressure prevailing in a line section (13) upstream of the first metering diaphragm (17).
  2. Hydraulic control circuit according to Claim 1,
    characterized in that the valve member (48) of the priority valve (45) is acted upon in the opening direction by a spring (51).
  3. Hydraulic control circuit according to Claim 1 or 2, characterized in that the priority valve (45) is developed as a proportional valve.
  4. Hydraulic control circuit according to a preceding claim, characterized in that the valve member (48) of the priority valve (45) can be acted upon in the closing direction by the pressure prevailing in the inflow line (13) upstream of the first pressure compensator (20).
  5. Hydraulic control circuit according to a preceding claim, characterized in that a control pressure chamber (49) on the valve member (48) of the priority valve (45) and the first port (46) of the priority valve (45) are connected to the inflow to the first metering diaphragm (17) on the same side of the first pressure compensator (20).
  6. Hydraulic control circuit according to a preceding claim, characterized in that a flow point can be connected, downstream of the first metering diaphragm (17), to the load signaling line (38) via a bypass line (62), and that a non-return valve (63) opening toward the load signaling line (38) is arranged in the bypass line (62).
  7. Hydraulic control circuit according to Claim 6, characterized in that between the non-return valve (63) in the bypass line (62) and the second port (47) of the priority valve (45) is arranged a non-return valve (64) blocking in the direction of this port (47).
EP97952950A 1997-02-04 1997-12-16 Hydraulic control circuit for a priority and for a secondary hydraulic consumer Expired - Lifetime EP0958455B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19703997 1997-02-04
DE19703997A DE19703997A1 (en) 1997-02-04 1997-02-04 Hydraulic control circuit for a priority and for a subordinate hydraulic consumer
PCT/EP1997/007072 WO1998034031A1 (en) 1997-02-04 1997-12-16 Hydraulic control circuit for a priority and for a secondary hydraulic consumer

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EP0958455A1 EP0958455A1 (en) 1999-11-24
EP0958455B1 true EP0958455B1 (en) 2003-04-23

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US (1) US6289675B1 (en)
EP (1) EP0958455B1 (en)
JP (1) JP4156037B2 (en)
KR (1) KR100528031B1 (en)
AT (1) ATE238497T1 (en)
DE (2) DE19703997A1 (en)
WO (1) WO1998034031A1 (en)

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KR20000070768A (en) 2000-11-25
DE19703997A1 (en) 1998-08-06
US6289675B1 (en) 2001-09-18
DE59709931D1 (en) 2003-05-28
KR100528031B1 (en) 2005-11-15
ATE238497T1 (en) 2003-05-15
JP4156037B2 (en) 2008-09-24
JP2001509867A (en) 2001-07-24
EP0958455A1 (en) 1999-11-24
WO1998034031A1 (en) 1998-08-06

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