EP0129652B1 - Hydraulic control system for the steering and power hydraulics of vehicles - Google Patents

Hydraulic control system for the steering and power hydraulics of vehicles Download PDF

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Publication number
EP0129652B1
EP0129652B1 EP84103939A EP84103939A EP0129652B1 EP 0129652 B1 EP0129652 B1 EP 0129652B1 EP 84103939 A EP84103939 A EP 84103939A EP 84103939 A EP84103939 A EP 84103939A EP 0129652 B1 EP0129652 B1 EP 0129652B1
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EP
European Patent Office
Prior art keywords
valve
hydraulic
pressure fluid
circuit
power
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
Application number
EP84103939A
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German (de)
French (fr)
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EP0129652A1 (en
Inventor
Heribert Dipl.-Landwirt Adams
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Kloeckner Humboldt Deutz AG
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Kloeckner Humboldt Deutz AG
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Priority to AT84103939T priority Critical patent/ATE27640T1/en
Publication of EP0129652A1 publication Critical patent/EP0129652A1/en
Application granted granted Critical
Publication of EP0129652B1 publication Critical patent/EP0129652B1/en
Expired legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/17—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors using two or more pumps
    • 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
    • F15B2211/20576—Systems with pumps with multiple pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30505—Non-return valves, i.e. check valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3105—Neutral or centre positions
    • F15B2211/3116—Neutral or centre positions the pump port being open in the centre position, e.g. so-called open centre
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40523—Flow control characterised by the type of flow control means or valve with flow dividers
    • F15B2211/4053—Flow control characterised by the type of flow control means or valve with flow dividers using 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
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/41554—Flow control characterised by the connections of the flow control means in the circuit being connected to a return line and a directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—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
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
    • F15B2211/7142—Multiple output members, e.g. multiple hydraulic motors or cylinders the output members being arranged in multiple groups
    • 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
    • F15B2211/78—Control of multiple output members
    • F15B2211/781—Control of multiple output members one or more output members having priority

Definitions

  • the invention relates to a hydraulic control system for the steering and working hydraulics including a controllable power lift system on vehicles, in particular agricultural tractors, with two hydraulic circuits, each connected to a hydraulic pump and connectable to one another by actuating a short-circuit valve, for supplying hydraulic consumers with hydraulic fluid, the first hydraulic circuit the hydraulic steering system is supplied by the hydraulic pump via an element that primarily supplies pressure fluid and the amount of fluid not required for the steering flows to the downstream power lift via one or more directional control valves for other consumers, and in the second hydraulic circuit the hydraulic pump supplies the hydraulic pump through the short-circuit valve with the when the fluid is not required Storage container is connected.
  • a control system of this type has become known [ ⁇ lhydraulik & Pneumatik 24 (1980) No. 11, p. 810, Figure 4], the one hydraulic pump being connected to a flow divider which primarily supplies the steering hydraulics with hydraulic fluid. The residual flow coming from the flow divider is fed to the power lift and is sufficient in terms of quantity for the regulating mode of operation.
  • the second hydraulic pump is connected directly to the reservoir via a connecting valve and to the hydraulic circuit of the first hydraulic pump via a check valve. When a directional valve for supplying one of the other consumers with pressure fluid is actuated, the changeover valve is closed by means of a control pressure, so that sufficient pressure fluid flows to the consumer through the combination of the two hydraulic circuits.
  • the second hydraulic circuit can only be used in conjunction with the first hydraulic circuit, so that the two hydraulic circuits cannot be used separately, as is desirable in some cases.
  • the invention is based on the object, while avoiding the described disadvantage, of improving a control system of the type outlined at the outset in such a way that the two hydraulic circuits present in the control system are also available separately from one another for the supply of hydraulic consumers if required. It should also be ensured that the connection valve does not respond to short control pulses from the power lift.
  • At least one directional valve for supplying other consumers with pressure fluid is arranged in the line between the hydraulic pump and the short-circuit valve in the second hydraulic circuit, and that, like the other directional valve, has a neutral circulation, that the output of the neutral circulation of the first-mentioned directional valve
  • a check valve is connected to the input of the directional control valve in the other hydraulic circuit, that the short-circuit valve normally connects the outlet of the neutral circulation of the first-mentioned directional control valve to the reservoir and, when the directional control valve in the other hydraulic circuit or a power lift control valve is actuated, this bypass closes so that the power lift Control valve can be actuated via a pilot valve and the pilot pressure for the control valve is simultaneously supplied to the short-circuit valve for actuation in the closing direction and that the supply of the pilot pressure to the short-circuit valve via an inlet-retarding throttle element.
  • the second hydraulic circuit can also be used for other consumers when operating the power lift in the first hydraulic circuit, since the power lift for the normal course of work (control) manages with the delivery volume of this hydraulic pump that is not used by the steering hydraulics.
  • a further development of the invention provides that the steering hydraulics for supplying hydraulic fluid is connected to the hydraulic pump via a priority valve.
  • the working resistance In such a hydraulic control system in which the like for controlling or regulating the power lift according to given setpoints or actual values of the position, the working resistance. required components of a working device are combined in one device, it is useful if the short-circuit valve is a component of the control device.
  • Two hydraulic pumps 1 and 2 which are preferably designed as tandem pumps, are connected on the suction side via lines 3 and 4 and a filter 5 and 6, respectively, to the reservoir 7 for pressure fluid.
  • the hydraulic pump 1 supplies a first hydraulic circuit with a steering hydraulic system 8, which is connected via a priority valve 10 to a line 11 emanating from the hydraulic pump on the pressure side.
  • a line 12 leads from the priority valve 10 back to the storage container 7.
  • the priority valve 10 is designed such that it only supplies the hydraulic fluid quantity required for steering to the steering hydraulics.
  • a line 13 leading from the priority valve 10 leads through a valve block 14 to a directional valve block 15 in which a directional valve 16 assigned to the first hydraulic circuit is shown in simplified form.
  • a control control unit 18 for a power lift is flanged to the directional valve block 15, the lifting cylinder of which is designated by 19.
  • the line 13 coming from the directional control valve 16 is connected to a control valve 20 on the input side.
  • the control valve 20 is connected on the output side through a line 21 to a line 22 which is connected to the reservoir 7 via a hydraulic fluid cooler 23 and a filter 24.
  • a line 25 branches off from the line 13 in the flow direction upstream of the control valve 20 and is connected to one end face 27 of the control valve 20 by means of a control line 26 and to a line 30 via a spring-reinforced check valve 28.
  • the line 30 connects the lifting cylinder 19 of the power lift via a flow control valve 31 to a pilot valve 32 of the power lift system arranged in the reservoir 7.
  • the pilot valve 32 designed as a three-way valve is also connected by a line 33 to the end face 35 of the control valve 20 which is loaded by a spring 34.
  • the pilot spool 32 is activated by a control linkage, not shown, which compares actual values of tensile force or position measurements with predetermined target values.
  • a short-circuit valve 37 which is loaded on its one end 38 in the closing direction by a spring 39 and the other end 40 of which is connected to the line 13 by a line 41.
  • the spring-side end face 38 of the short-circuit valve 37 is connected to the line 33 by control lines 42, 43, a check valve 44 being arranged in line 42 and a throttle element 45 being arranged in line 43.
  • a line 46 leads to the line 22 on the return side.
  • a line 47 in which a throttle element 48 is arranged.
  • the other hydraulic pump 2 is connected to a directional valve block 51 on the pressure side by means of a line 50 and a valve block 14 to supply a second hydraulic circuit, a single directional valve 52 being shown in simplified form.
  • the line 50 is connected via a check valve 53 to the line 13 of the first hydraulic circuit supplied by the hydraulic pump 1.
  • the check valve 53 In the flow direction upstream of the check valve 53, there is a connection between the line 50 in the inlet of the short-circuit valve 37 through a line 54.
  • the hydraulic pump 1 continuously pumps hydraulic fluid into the first hydraulic circuit during operation, the hydraulic steering system being primarily supplied with hydraulic fluid.
  • the priority valve 10 only controls the hydraulic fluid quantity required for steering directly to the steering hydraulics 8, while for the rest of the time in which there is no steering, the full pressure medium flow is available to the other consumers, in particular this hydraulic circuit. If no other consumer is connected to the first hydraulic circuit, the amount of hydraulic fluid not required by the steering flows through line 13 and directional valve block 15 as well as through control valve 20 and lines 21 and 22 back to reservoir 7.
  • pilot valve 32 becomes on these acting sink pulses from the neutral position shown to the right and with lifting pulses to the left.
  • the short-circuit valve 37 On the end face 40 of the short-circuit valve 37, the pressure present in the line 13 is constantly present, while on the end face 38 of the open control spool 32, only the force of the spring 39 acts.
  • the short-circuit valve 37 is thus in the through position shown.
  • the pilot valve 32 When the power lift is operating, the pilot valve 32 is only moved briefly from the neutral position in one direction or the other due to the short control times that occur during "regulation" thereof.
  • these short movements of the pilot spool 32 are in no way sufficient to build up a control pressure on the end face 38 of the short-circuit valve 37 as a result of the throttle 45 connected upstream as a delay element, which, supported by the force of the spring 39, is large enough to influence the short-circuit valve 37 in the closing direction.
  • a directional control valve 16 in the directional control valve block 15 When a directional control valve 16 in the directional control valve block 15 is activated, the pressure medium in line 13 is shut off and supplied to a consumer (not shown). The line 13 is depressurized behind the directional control valve 16. The short-circuit valve 37 is then moved in the closing direction by the force of the spring 39 and the outflow of the pressure medium from the circuit of the hydraulic pump 2 is shut off via the lines 54, 46.
  • the directional control valves 16 always have the flow rates of both hydraulic circuits available, provided directional control valves 52 are not activated.
  • One or more consumers can be connected to the second hydraulic circuit supplied by the hydraulic pump 2 independently of the first hydraulic circuit and can be switched on and off via the directional valves 52.
  • one of the consumers connected to the second hydraulic circuit via one of the directional valves 52 can be a mower motor, while the lifting cylinder of the mower is connected to the first hydraulic circuit via one of the directional valves 16.

Abstract

1. A hydraulic control system for the steering and other hydraulically energized equipment - including a controllable power lift (18, 19, 32) - of a motor vehicle, particularly of a tractor, the system comprising two hydraulic circuits serving to feed pressure fluid to the hydraulically operable devices, each circuit including its respective hydraulic pump (1, 2) and both being interconnectable by actuating a sequence valve (37), in which the hydraulic pump (1) of the first circuit is arranged to feed pressure fluid to a hydraulic power steering device (8) via an element (10) adapted to accord priority to supplying this device, in which any pressure fluid not required for steering is arranged to flow via one or more distributing valves (16) for the other consuming devices to the - subsequent - power lift (19), and in which the second hydraulic circuit's hydraulic pump (2) communicates, if pressure fluid is not required, via the sequence valve (37) with a pressure fluid reservoir (7), characterized in that a duct (50) of the second hydraulic circuit includes at least one distributing valve (52) which serves to feed pressure fluid to the other consuming devices, which is located between the hydraulic pump (2) and the sequence valve (37) and which is provided, like the other distributing valve (16), with a neutral passage, that the outlet of the first mentioned distributing valve's (52) neutral passage is connected via a nonreturn valve (53) to the inlet of the distributing valve (16) of the first hydraulic circuit, that the sequence valve (37) while normally connecting the outlet of the first-mentioned distributing valve's (52) neutral passage with the reservoir (7) closes this by-pass if either the distributing valve (16) of the first hydraulic circuit or a power-lift control valve (20) is actuated, that the power-lift control valve (20) is arranged to be actuated by a pilot valve (32), that the pilot pressure for the control valve (20) is also simultaneously transmitted to the sequence valve (37) so as to urge the latter towards its closing position, and in that the transmission of the pilot pressure to the sequence valve (37) is effected via a flow-inhibiting throttling member (throttling relief valves 44, 45).

Description

Die Erfindung bezieht sich auf ein hydraulisches Steuersystem für die Lenk- und Arbeitshydraulik einschliesslich einer regelbaren Kraftheberanlage an Fahrzeugen, insbesondere Ackerschlepper, mit zwei an je eine Hydropumpe angeschlossene und durch Betätigung eines Kurzschlussventils miteinander verbindbare Hydraulikkreise zur Versorgung hydraulischer Verbraucher mit Druckflüssigkeit, wobei im ersten Hydraulikkreis von der Hydropumpe die Lenkhydraulik über ein dieser vorrangig Druckflüssigkeit zuführendes Element versorgt wird und die für die Lenkung nicht benötigte Flüssigkeitsmenge dem nachgeschalteten Kraftheber über ein oder mehrere Wegeventile für sonstige Verbraucher zufliesst und wobei im zweiten Hydraulikkreis die Hydropumpe bei nicht benötigter Druckflüssigkeit durch das Kurzschlussventil mit dem Vorratsbehälter in Verbindung steht.The invention relates to a hydraulic control system for the steering and working hydraulics including a controllable power lift system on vehicles, in particular agricultural tractors, with two hydraulic circuits, each connected to a hydraulic pump and connectable to one another by actuating a short-circuit valve, for supplying hydraulic consumers with hydraulic fluid, the first hydraulic circuit the hydraulic steering system is supplied by the hydraulic pump via an element that primarily supplies pressure fluid and the amount of fluid not required for the steering flows to the downstream power lift via one or more directional control valves for other consumers, and in the second hydraulic circuit the hydraulic pump supplies the hydraulic pump through the short-circuit valve with the when the fluid is not required Storage container is connected.

Es ist ein Steuersystem dieser Art bekanntgeworden [Ölhydraulik & Pneumatik 24 (1980) Nr. 11, S. 810, Bild 4], wobei die eine Hydropumpe mit einem Mengenteiler verbunden ist, der die Lenkhydraulik vorrangig mit Druckflüssigkeit versorgt. Der vom Mengenteiler ausgehende Reststrom wird dem Kraftheber zugeführt und reicht mengenmässig für die regelnde Arbeitsweise desselben aus. Die zweite Hydropumpe steht über ein Zuschaltventil unmittelbar mit dem Vorratsbehälter und über ein Rückschlagventil mit dem Hydraulikkreis der ersten Hydropumpe in Verbindung. Bei Betätigung eines Wegeventils zur Versorgung eines der sonstigen Verbraucher mit Druckflüssigkeit wird das-Umschaltventil über einen Steuerdruck geschlossen, so dass dem Verbraucher durch den Zusammenschluss beider Hydraulikkreise ausreichend Druckflüssigkeit zufliesst. Bei diesem bekannten Steuersystem ist jedoch der zweite Hydraulikkreis nur in Verbindung mit dem ersten Hydraulikkreis verwendbar, so dass keine getrennte Nutzung der beiden Hydraulikkreise, wie dies für manche Fälle wünschenswert ist, durchgeführt werden kann.A control system of this type has become known [Ölhydraulik & Pneumatik 24 (1980) No. 11, p. 810, Figure 4], the one hydraulic pump being connected to a flow divider which primarily supplies the steering hydraulics with hydraulic fluid. The residual flow coming from the flow divider is fed to the power lift and is sufficient in terms of quantity for the regulating mode of operation. The second hydraulic pump is connected directly to the reservoir via a connecting valve and to the hydraulic circuit of the first hydraulic pump via a check valve. When a directional valve for supplying one of the other consumers with pressure fluid is actuated, the changeover valve is closed by means of a control pressure, so that sufficient pressure fluid flows to the consumer through the combination of the two hydraulic circuits. In this known control system, however, the second hydraulic circuit can only be used in conjunction with the first hydraulic circuit, so that the two hydraulic circuits cannot be used separately, as is desirable in some cases.

Der Erfindung liegt die Aufgabe zugrunde, unter Vermeidung des geschilderten Nachteils ein Steuersystem der eingangs umrissenen Gattung dahingehend zu verbessern, dass die beiden im Steuersystem vorhandenen Hydraulikkreise bei Bedarf auch getrennt voneinander für die Versorgung von hydraulischen Verbrauchern zur Verfügung stehen. Dabei soll ferner sichergestellt sein, dass das Zuschaltventil auf kurze Regelimpulse des Krafthebers nicht anspricht.The invention is based on the object, while avoiding the described disadvantage, of improving a control system of the type outlined at the outset in such a way that the two hydraulic circuits present in the control system are also available separately from one another for the supply of hydraulic consumers if required. It should also be ensured that the connection valve does not respond to short control pulses from the power lift.

Die Aufgabe wird erfindungsgemäss dadurch gelöst, dass im zweiten Hydraulikkreis in der Leitung zwischen der Hydropumpe und dem Kurzschlussventil zumindest ein Wegeventil zur Versorgung sonstiger Verbraucher mit Druckflüssigkeit angeordnet ist, dass ebenso wie das andere Wegeventil einen Neutralumlauf aufweist, dass der Ausgang des Neutralumlaufs des erstgenannten Wegeventils über ein Rückschlagventil mit dem Eingang des Wegeventils im anderen Hydraulikkreislauf verbunden ist, dass das Kurzschlussventil normal den Ausgang des Neutralumlaufs des erstgenannten Wegeventils mit dem Vorratsbehälter verbindet und bei Betätigung des Wegeventils im anderen Hydraulikkreislauf oder eines Kraftheber-Steuerventils diesen Bypass schliesst, dass das Kraftheber-Steuerventil über ein Vorsteuerventil betätigbar ist und der Vorsteuerdruck für das Steuerventil gleichzeitig dem Kurzschlussventil zur Betätigung in Schliessrichtung zugeführt wird und dass die Zufuhr des Vorsteuerdrucks zum Kurzschlussventil über ein zulaufverzögerndes Drosselorgan erfolgt.The object is achieved in that at least one directional valve for supplying other consumers with pressure fluid is arranged in the line between the hydraulic pump and the short-circuit valve in the second hydraulic circuit, and that, like the other directional valve, has a neutral circulation, that the output of the neutral circulation of the first-mentioned directional valve A check valve is connected to the input of the directional control valve in the other hydraulic circuit, that the short-circuit valve normally connects the outlet of the neutral circulation of the first-mentioned directional control valve to the reservoir and, when the directional control valve in the other hydraulic circuit or a power lift control valve is actuated, this bypass closes so that the power lift Control valve can be actuated via a pilot valve and the pilot pressure for the control valve is simultaneously supplied to the short-circuit valve for actuation in the closing direction and that the supply of the pilot pressure to the short-circuit valve via an inlet-retarding throttle element.

Durch diese Massnahmen wird erreicht, dass beide Hydraulikkreise auch unabhängig voneinander genutzt werden können. Auch beim Betrieb des Krafthebers im ersten Hydraulikkreis kann der zweite Hydraulikkreis für andere Verbraucher genutzt werden, da der Kraftheber für den normalen Arbeitsverlauf (Regelung) mit der von der Lenkhydraulik nicht beanspruchten Fördermenge dieser Hydropumpe auskommt.These measures ensure that both hydraulic circuits can also be used independently of one another. The second hydraulic circuit can also be used for other consumers when operating the power lift in the first hydraulic circuit, since the power lift for the normal course of work (control) manages with the delivery volume of this hydraulic pump that is not used by the steering hydraulics.

Damit dem Kraftheber für die Regelung stets eine möglichst grosse Druckmittelmenge zur Verfügung steht, ist in Weiterbildung der Erfindung vorgesehen, dass die Lenkhydraulik zur Versorgung mit Druckflüssigkeit über ein Prioritätsventil mit der Hydraulikpumpe verbunden ist.In order that the largest possible amount of pressure medium is always available to the power lift for the control, a further development of the invention provides that the steering hydraulics for supplying hydraulic fluid is connected to the hydraulic pump via a priority valve.

Bei einem derartigen hydraulischen Steuersystem, bei dem die zur Steuerung bzw. Regelung des Krafthebers nach gegebenen Sollwerten bzw. Istwerten der Lage, des Arbeitswiderstandes od.dgl. eines Arbeitsgerätes erforderlichen Bauelemente in einem Gerät zusammengefasst sind, ist es zweckdienlich, wenn das Kurzschlussventil ein Bestandteil des Regelsteuergerätes ist.In such a hydraulic control system in which the like for controlling or regulating the power lift according to given setpoints or actual values of the position, the working resistance. required components of a working device are combined in one device, it is useful if the short-circuit valve is a component of the control device.

Ein Ausführungsbeispiel der Erfindung wird im folgenden anhand der Zeichnung näher beschrieben. Die einzige Darstellung zeigt schematisch ein Steuersystem gemäss der Erfindung.An embodiment of the invention is described below with reference to the drawing. The only illustration shows schematically a control system according to the invention.

Zwei Hydropumpen 1 und 2, die vorzugsweise als Tandempumpen ausgeführt sind, stehen saugseitig über Leitungen 3 bzw. 4 sowie je einen Filter 5 bzw. 6 mit dem Vorratsbehälter 7 für Druckflüssigkeit in Verbindung. Die Hydropumpe 1 versorgt einen ersten Hydraulikkreis mit einer Lenkhydraulik 8, die über ein Prioritätsventil 10 an eine von der Hydropumpe druckseitig ausgehende Leitung 11 angeschlossen ist. Vom Prioritätsventil 10 führt eine Leitung 12 zurück zum Vorratsbehälter 7. Das Prioritätsventil 10 ist so ausgebildet, dass es nur die unmittelbar zum Lenken benötigte Druckflüssigkeitsmenge der Lenkhydraulik zuführt. Eine vom Prioritätsventil 10 abgehende Leitung 13 führt durch einen Ventilblock 14 zu einem Wegeventilblock 15, in dem ein dem ersten Hydraulikkreis zugeordnetes Wegeventil 16 vereinfacht dargestellt ist. An den Wegeventilblock 15 ist ein Regelsteuergerät 18 für einen Kraftheber angeflanscht, dessen Hubzylinder mit 19 bezeichnet ist. Innerhalb des Regelsteuergerätes 18 ist die vom Wegeventil 16 kommende Leitung 13 mit einem Steuerventil 20 eingangsseitig verbunden. Das Steuerventil 20 steht ausgangsseitig durch eine Leitung 21 mit einer Leitung 22 in Verbindung, die über einen Druckflüssigkeitskühler 23 und einen Filter 24 mit dem Vorratsbehälter 7 verbunden ist.Two hydraulic pumps 1 and 2, which are preferably designed as tandem pumps, are connected on the suction side via lines 3 and 4 and a filter 5 and 6, respectively, to the reservoir 7 for pressure fluid. The hydraulic pump 1 supplies a first hydraulic circuit with a steering hydraulic system 8, which is connected via a priority valve 10 to a line 11 emanating from the hydraulic pump on the pressure side. A line 12 leads from the priority valve 10 back to the storage container 7. The priority valve 10 is designed such that it only supplies the hydraulic fluid quantity required for steering to the steering hydraulics. A line 13 leading from the priority valve 10 leads through a valve block 14 to a directional valve block 15 in which a directional valve 16 assigned to the first hydraulic circuit is shown in simplified form. A control control unit 18 for a power lift is flanged to the directional valve block 15, the lifting cylinder of which is designated by 19. Within the control unit 18, the line 13 coming from the directional control valve 16 is connected to a control valve 20 on the input side. The control valve 20 is connected on the output side through a line 21 to a line 22 which is connected to the reservoir 7 via a hydraulic fluid cooler 23 and a filter 24.

Von der Leitung 13 zweigt in Strömungsrichtung vor dem Steuerventil 20 eine Leitung 25 ab, die mittels einer Steuerleitung 26 mit der einen Stirnseite 27 des Steuerventils 20 und über ein federverstärktes Rückschlagventil 28 mit einer Leitung 30 in Verbindung steht. Die Leitung 30 verbindet den Hubzylinder 19 des Krafthebers über ein Stromregelventil 31 mit einem im Vorratsbehälter 7 angeordneten Vorsteuerschieber 32 der Kraftheberanlage. Der als Dreiwegeventil ausgebildete Vorsteuerschieber 32 steht ausserdem durch eine Leitung 33 mit der durch eine Feder 34 belasteten Stirnseite 35 des Steuerventils 20 in Verbindung. Der Vorsteuerschieber 32 wird von einem nicht gezeichneten Regelgestänge aktiviert, das Istwerte von Zugkraft- oder Positionsmesswerten mit vorgegebenen Sollwerten vergleicht.A line 25 branches off from the line 13 in the flow direction upstream of the control valve 20 and is connected to one end face 27 of the control valve 20 by means of a control line 26 and to a line 30 via a spring-reinforced check valve 28. The line 30 connects the lifting cylinder 19 of the power lift via a flow control valve 31 to a pilot valve 32 of the power lift system arranged in the reservoir 7. The pilot valve 32 designed as a three-way valve is also connected by a line 33 to the end face 35 of the control valve 20 which is loaded by a spring 34. The pilot spool 32 is activated by a control linkage, not shown, which compares actual values of tensile force or position measurements with predetermined target values.

Im Regelsteuergerät 18 des Krafthebers ist ferner ein Kurzschlussventil 37 untergebracht, das an seiner einen Stirnseite 38 im Schliesssinn durch eine Feder 39 belastet ist und deren andere Stirnseite 40 durch eine Leitung 41 mit der Leitung 13 verbunden ist. Die federseitige Stirnseite 38 des Kurzschlussventils 37 steht durch Steuerleitungen 42, 43 mit der Leitung 33 in Verbindung, wobei in der Leitung 42 ein Rückschlagventil 44 sowie in der Leitung 43 ein Drosselorgan 45 angeordnet ist. Von dem als Zweiwegeventil ausgebildeten Kurzschlussventil 37 führt rücklaufseitig eine Leitung 46 zur Leitung 22. Ausserdem besteht auch eine Verbindung der Leitung 43 mit der Leitung 13 mittels einer Leitung 47, in der ein Drosselorgan 48 angeordnet ist.In the control unit 18 of the power lift there is also a short-circuit valve 37, which is loaded on its one end 38 in the closing direction by a spring 39 and the other end 40 of which is connected to the line 13 by a line 41. The spring-side end face 38 of the short-circuit valve 37 is connected to the line 33 by control lines 42, 43, a check valve 44 being arranged in line 42 and a throttle element 45 being arranged in line 43. From the short-circuit valve 37, which is designed as a two-way valve, a line 46 leads to the line 22 on the return side. There is also a connection of the line 43 to the line 13 by means of a line 47 in which a throttle element 48 is arranged.

Die andere Hydropumpe 2 ist zur Versorgung eines zweiten Hydraulikkreises druckseitig durch eine Leitung 50 und einen Ventilblock 14 mit einem Wegeventilblock 51 verbunden, wobei ein einzelnes Wegeventil 52 vereinfacht dargestellt ist. In Strömungsrichtung hinter dem Wegeventilblock 51 ist die Leitung 50 über ein Rückschlagventil 53 an die Leitung 13 des durch die Hydropumpe 1 versorgten ersten Hydraulikkreises angeschlossen. In Strömungsrichtung vor dem Rückschlagventil 53 besteht zwischen der Leitung 50 in dem Eingang des Kurzschlussventils 37 eine Verbindung durch eine Leitung 54.The other hydraulic pump 2 is connected to a directional valve block 51 on the pressure side by means of a line 50 and a valve block 14 to supply a second hydraulic circuit, a single directional valve 52 being shown in simplified form. In the flow direction behind the directional valve block 51, the line 50 is connected via a check valve 53 to the line 13 of the first hydraulic circuit supplied by the hydraulic pump 1. In the flow direction upstream of the check valve 53, there is a connection between the line 50 in the inlet of the short-circuit valve 37 through a line 54.

Die Hydropumpe 1 fördert beim Betrieb ständig Druckflüssigkeit in den ersten Hydraulikkreis, wobei die Lenkhydraulik vorrangig mit Druckflüssigkeit versorgt wird. Das Prioritätsventil 10 steuert dabei nur die unmittelbar zum Lenken erforderliche Druckflüssigkeitsmenge der Lenkhydraulik 8 zu, während für die übrige Zeit, in der nicht gelenkt wird, der volle Druckmittelstrom den übrigen Verbrauchern, insbesondere dieses Hydraulikkreises, zur Verfügung steht. Wenn kein anderer Verbraucher am ersten Hydraulikkreis angeschlossen ist, fliesst die von der Lenkung nicht benötigte Druckflüssigkeitsmenge durch die Leitung 13 und den Wegeventilblock 15 sowie durch das Steuerventil 20 und die Leitungen 21 und 22 zurück zum Vorratsbehälter 7. Bei eingeschaltetem Kraftheber wird der Vorsteuerschieber 32 bei auf diesen einwirkenden Senken-Impulsen aus der gezeigten Neutralstellung nach rechts und bei Heben-Impulsen nach links bewegt. Bei letztgenannter Einwirkung baut sich in der Leitung 33 über die Leitung 47 und das Drosselorgan 48 ein Steuerdruck auf, der unterstützt durch die Kraft der Feder 34 das Steuerventil 20 im Schliesssinn betätigt, so dass durch die Leitung 25, das Rückschlagventil 28 und die Leitung 30 Druckflüssigkeit dem Hubzylinder 19 zufliesst. Es folgt ein Hebevorgang des Krafthebers bzw. des angeschlossenen Arbeitsgerätes. Wird dagegen der Vorsteuerschieber 32 aus der Neutralstellung nach rechts bewegt, ist die Steuerleitung 33 druckentlastet, wobei sich das Steuerventil 20 in der gezeigten Offenstellung befindet. Gleichzeitig kann durch die Leitung 30 und das Stromregelventil 31 Druckflüssigkeit aus dem Hubzylinder 19 abströmen, so dass ein Senkvorgang am Kraftheber bzw. am Arbeitsgerät erfolgt.The hydraulic pump 1 continuously pumps hydraulic fluid into the first hydraulic circuit during operation, the hydraulic steering system being primarily supplied with hydraulic fluid. The priority valve 10 only controls the hydraulic fluid quantity required for steering directly to the steering hydraulics 8, while for the rest of the time in which there is no steering, the full pressure medium flow is available to the other consumers, in particular this hydraulic circuit. If no other consumer is connected to the first hydraulic circuit, the amount of hydraulic fluid not required by the steering flows through line 13 and directional valve block 15 as well as through control valve 20 and lines 21 and 22 back to reservoir 7. When the power lift is switched on, pilot valve 32 becomes on these acting sink pulses from the neutral position shown to the right and with lifting pulses to the left. With the latter action, a control pressure builds up in line 33 via line 47 and throttle element 48, which, supported by the force of spring 34, actuates control valve 20 in the closing direction, so that through line 25, check valve 28 and line 30 Hydraulic fluid flows to the lifting cylinder 19. A lifting process of the power lift or the connected implement follows. If, on the other hand, the pilot spool 32 is moved to the right from the neutral position, the control line 33 is relieved of pressure, the control valve 20 being in the open position shown. At the same time, pressure fluid can flow out of the lifting cylinder 19 through the line 30 and the flow control valve 31, so that a lowering operation takes place on the power lift or on the implement.

An der Stirnseite 40 des Kurzschlussventils 37 steht ständig der in der Leitung 13 vorhandene Druck an, während an dessen Stirnseite 38 bei geöffnetem Vorsteuerschieber 32 nur die Kraft der Feder 39 einwirkt. Das Kurzschlussventil 37 befindet sich somit in der gezeigten Durchgangsstellung. Beim Betrieb des Krafthebers wird bei «Regelung» desselben der Vorsteuerschieber 32 infolge der dabei auftretenden kurzen Steuerzeiten immer nur kurzzeitig aus der Neutralstellung in die eine oder andere Richtung bewegt. Diese kurzen Bewegungen des Vorsteuerschiebers 32 reichen jedoch keineswegs aus, an der Stirnseite 38 des Kurzschlussventils 37 infolge der als Verzögerungselement vorgeschalteten Drossel 45 einen Steuerdruck aufzubauen, der unterstützt durch die Kraft der Feder 39 gross genug ist, das Kurzschlussventil 37 im Schliesssinn zu beeinflussen. Erst bei längerer Beanspruchung des Krafthebers, beispielsweise beim Ausheben eines Arbeitsgerätes, wird das Kurzschlussventil 37 infolge des Druckaufbaues an der Stirnseite 38 unterstützt durch die Kraft der Feder 39 in Schliessstellung versetzt. Hierdurch wird der Rücklauf der Druckflüssigkeit aus dem durch die Hydropumpe 2 gespeisten zweiten Hydraulikkreis durch die Leitung 54, das Kurzschlussventil 37 und die Leitungen 46, 22 zum Vorratsbehälter 7 gesperrt, und es strömt Druckflüssigkeit aus dem zweiten Hydraulikkreis durch das Rückschlagventil 53 in die Leitung 13 des ersten Hydraulikkreises. Damit wird dem ersten Hydraulikkreis die zum schnellen Ausheben eines Arbeitsgerätes erforderliche zusätzliche Druckmittelmenge zugeführt.On the end face 40 of the short-circuit valve 37, the pressure present in the line 13 is constantly present, while on the end face 38 of the open control spool 32, only the force of the spring 39 acts. The short-circuit valve 37 is thus in the through position shown. When the power lift is operating, the pilot valve 32 is only moved briefly from the neutral position in one direction or the other due to the short control times that occur during "regulation" thereof. However, these short movements of the pilot spool 32 are in no way sufficient to build up a control pressure on the end face 38 of the short-circuit valve 37 as a result of the throttle 45 connected upstream as a delay element, which, supported by the force of the spring 39, is large enough to influence the short-circuit valve 37 in the closing direction. Only when the power lift is used for a longer period of time, for example when lifting an implement, is the short-circuit valve 37, due to the pressure build-up on the end face 38, supported by the force of the spring 39 in the closed position. As a result, the return flow of the pressure fluid from the second hydraulic circuit fed by the hydraulic pump 2 is blocked through the line 54, the short-circuit valve 37 and the lines 46, 22 to the reservoir 7, and pressure fluid flows from the second hydraulic circuit through the check valve 53 into the line 13 of the first hydraulic circuit. The first hydraulic circuit is thus supplied with the additional quantity of pressure medium required for the quick lifting of an implement.

Bei der Ansteuerung eines Wegeventils 16 im Wegeventilblock 15 wird das Druckmittel in Leitung 13 abgesperrt und einem nicht gezeichneten Verbraucher zugeführt. Die Leitung 13 wird hinter dem Wegeventil 16 drucklos. Das Kurzschlussventil 37 wird dann durch die Kraft der Feder 39 in Schliessrichtung verschoben und der Abfluss des Druckmittels aus dem Kreis der Hydropumpe 2 über die Leitungen 54, 46 abgesperrt. Den Wegeventilen 16 stehen immer die Förderströme beider Hydraulikkreise zur Verfügung, sofern Wegeventile 52 nicht angesteuert sind.When a directional control valve 16 in the directional control valve block 15 is activated, the pressure medium in line 13 is shut off and supplied to a consumer (not shown). The line 13 is depressurized behind the directional control valve 16. The short-circuit valve 37 is then moved in the closing direction by the force of the spring 39 and the outflow of the pressure medium from the circuit of the hydraulic pump 2 is shut off via the lines 54, 46. The directional control valves 16 always have the flow rates of both hydraulic circuits available, provided directional control valves 52 are not activated.

An den von der Hydropumpe 2 versorgten zweiten Hydraulikkreis können unabhängig vom ersten Hydraulikkreis ein oder mehrere Verbraucher angeschlossen werden, die über die Wegeventile 52 ein- bzw. ausschaltbar sind. So kann einer der an den zweiten Hydraulikkreis über eines der Wegeventile 52 angeschlossene Verbraucher beispielsweise ein Mähwerksmotor sein, während der Aushubzylinder des Mähwerks über eines der Wegeventile 16 mit dem ersten Hydraulikkreis in Verbindung steht. Es ist aber auch möglich, beim Betrieb des Krafthebers über den ersten Hydraulikkreis beispielsweise einen hydraulischen Dauerverbraucher mit dem zweiten Hydraulikkreis über eines der Wegeventile 52 zu betreiben.One or more consumers can be connected to the second hydraulic circuit supplied by the hydraulic pump 2 independently of the first hydraulic circuit and can be switched on and off via the directional valves 52. For example, one of the consumers connected to the second hydraulic circuit via one of the directional valves 52 can be a mower motor, while the lifting cylinder of the mower is connected to the first hydraulic circuit via one of the directional valves 16. However, it is also possible to operate, for example, a permanent hydraulic consumer with the second hydraulic circuit via one of the directional control valves 52 when the power lift is operated via the first hydraulic circuit.

Claims (3)

1. A hydraulic control system for the steering and other hydraulically energized equipment - including a controllable power lift (18, 19, 32) - of a motor vehicle, particularly of a tractor, the system comprising two hydraulic circuits serving to feed pressure fluid to the hydraulically operable devices, each circuit including its respective hydraulic pump (1, 2) and both being interconnectable by actuating a sequence valve (37), in which the hydraulic pump (1) of the first circuit is arranged to feed pressure fluid to a hydraulic power steering device (8) via an element (10) adapted to accord priority to supplying this device, in which any pressure fluid not required for steering is arranged to flow via one or more distributing valves (16) for the other consuming devices to the - subsequent - power lift (19), and in which the second hydraulic circuit's hydraulic pump (2) communicates, if pressure fluid is not required, via the sequence valve (37) with a pressure fluid reservoir (7), characterized in that a duct (50) of the second hydraulic circuit includes at least one distributing valve (52) which serves to feed pressure fluid to the other consuming devices, which is located between the hydraulic pump (2) and the sequence valve (37) and which is provided, like the other distributing valve (16), with a neutral passage, that the outlet of the first mentioned distributing valve's (52) neutral passage is connected via a nonreturn valve (53) to the inlet of the distributing valve (16) of the first hydraulic circuit, that the sequence valve (37) while normally connecting the outlet of the first-mentioned distributing valve's (52) neutral passage with the reservoir (7) closes this by-pass if either the distributing valve (16) of the first hydraulic circuit or a power-lift control valve (20) is actuated, that the power-lift control valve (20) is arranged to be actuated by a pilot valve (32), that the pilot pressure for the control valve (20) is also simultaneously transmitted to the sequence valve (37) so as to urge the latter towards its closing position, and in that the transmission of the pilot pressure to the sequence valve (37) is effected via a flow-inhibiting throttling member (throttling relief valves 44, 45).
2. A control system according to claim 1, characterized in that the hydraulic power steering device (8) for its supply with pressure fluid is connected to the hydraulic pump (1) via the priority-according device (10) which is a valve.
3. A control system according to claim 1 or claim 2, in which elements required for controlling or adjusting the power lift (19) in accordance with predetermined nominal values and, respectively, actual values relating to the position, working resistance or the like of an implement are combined in one appliance, characterized in that the divertor valve (37) forms a part of the controlling and adjusting appliance (18).
EP84103939A 1983-05-28 1984-04-09 Hydraulic control system for the steering and power hydraulics of vehicles Expired EP0129652B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT84103939T ATE27640T1 (en) 1983-05-28 1984-04-09 HYDRAULIC CONTROL SYSTEM FOR STEERING AND WORKING HYDRAULICS ON VEHICLES.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19833319533 DE3319533A1 (en) 1983-05-28 1983-05-28 HYDRAULIC CONTROL SYSTEM FOR THE STEERING AND WORKING HYDRAULICS ON VEHICLES
DE3319533 1983-05-28

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EP0129652A1 EP0129652A1 (en) 1985-01-02
EP0129652B1 true EP0129652B1 (en) 1987-06-03

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AT (1) ATE27640T1 (en)
DE (2) DE3319533A1 (en)

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US5332053A (en) * 1993-01-26 1994-07-26 Aquilon Technologies Inc. Hydraulic drive system
CN110206776A (en) * 2019-07-16 2019-09-06 郑州宇通重工有限公司 A kind of hydraulic pressure maintaining and self-unloading energy conservation valve group
IT202100010601A1 (en) * 2021-04-27 2022-10-27 Cnh Ind Italia Spa HYDRAULIC CIRCUIT FOR AN AGRICULTURAL VEHICLE EQUIPPED WITH AN ANTI-SATURATION SYSTEM AND ANTI-SATURATION CONTROL METHOD
IT202100010577A1 (en) * 2021-04-27 2022-10-27 Cnh Ind Italia Spa HYDRAULIC CIRCUIT FOR AN AGRICULTURAL VEHICLE EQUIPPED WITH AN ANTI-SATURATION SYSTEM AND ANTI-SATURATION CONTROL METHOD

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US3448576A (en) * 1967-08-17 1969-06-10 Westinghouse Air Brake Co Fluid control system
FR2039123A1 (en) * 1969-12-19 1971-01-15 Poclain Sa
DE2437262B2 (en) * 1974-08-02 1976-09-02 Klöckner-Humboldt-Deutz AG, 5000 Köln HYDRAULIC CONTROL DEVICE FOR AN AGRICULTURAL VEHICLE
DE2458897A1 (en) * 1974-12-12 1976-06-24 Int Harvester Co ELECTRICAL CONTROL DEVICE FOR DISTRIBUTION OF PRESSURE LIQUID FROM A PRESSURE FLUID SOURCE TO SEVERAL DIFFERENT RANKING HYDRAULIC SYSTEMS
DE2625101C2 (en) * 1976-06-04 1985-11-14 Robert Bosch Gmbh, 7000 Stuttgart Hydraulic control device for the volume flow-dependent distribution of hydraulic fluid between two systems
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DE2855749A1 (en) * 1978-12-22 1980-06-26 Int Harvester Co HYDRAULIC CONTROL DEVICE FOR DISTRIBUTING PRESSURE LIQUID AT LEAST ONE, IN PARTICULAR, FROM TWO PRESSURE LIQUID SOURCES TO SEVERAL VARIOUS CONSUMERS
DE3237019C2 (en) * 1981-10-07 1994-07-28 Linde Ag Lift truck with a steering system with hydrostatic power steering system

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EP0129652A1 (en) 1985-01-02
ATE27640T1 (en) 1987-06-15
DE3319533A1 (en) 1984-11-29
DE3464083D1 (en) 1987-07-09

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