EP1252449A1 - Method and device for controlling a lift cylinder, especially of working machines - Google Patents

Method and device for controlling a lift cylinder, especially of working machines

Info

Publication number
EP1252449A1
EP1252449A1 EP01902390A EP01902390A EP1252449A1 EP 1252449 A1 EP1252449 A1 EP 1252449A1 EP 01902390 A EP01902390 A EP 01902390A EP 01902390 A EP01902390 A EP 01902390A EP 1252449 A1 EP1252449 A1 EP 1252449A1
Authority
EP
European Patent Office
Prior art keywords
cylinder
pressure
check valve
channel
suction
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.)
Granted
Application number
EP01902390A
Other languages
German (de)
French (fr)
Other versions
EP1252449B1 (en
Inventor
Jürgen Weber
Volker BÖSEBECH
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
CNH Industrial Baumaschinen GmbH
Original Assignee
O&K Orenstein and Koppel GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by O&K Orenstein and Koppel GmbH filed Critical O&K Orenstein and Koppel GmbH
Publication of EP1252449A1 publication Critical patent/EP1252449A1/en
Application granted granted Critical
Publication of EP1252449B1 publication Critical patent/EP1252449B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

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
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of 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
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/024—Systems essentially incorporating special features for controlling the speed or actuating force of an output member by means of differential connection of the servomotor lines, e.g. regenerative circuits
    • 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
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/021—Valves for interconnecting the fluid chambers of an actuator
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/024—Systems essentially incorporating special features for controlling the speed or actuating force of an output member by means of differential connection of the servomotor lines, e.g. regenerative circuits
    • F15B2011/0243—Systems essentially incorporating special features for controlling the speed or actuating force of an output member by means of differential connection of the servomotor lines, e.g. regenerative circuits the regenerative circuit being activated or deactivated automatically
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30505—Non-return valves, i.e. check valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/35—Directional control combined with flow control
    • F15B2211/353—Flow control by regulating means in 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
    • F15B2211/76—Control of force or torque of the output member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/775—Combined control, e.g. control of speed and force for providing a high speed approach stroke with low force followed by a low speed working stroke with high force, e.g. for a hydraulic press
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/80—Other types of control related to particular problems or conditions
    • F15B2211/88—Control measures for saving energy

Definitions

  • the invention is directed to a method and a device for controlling a lifting cylinder of the type specified in claims 1 and 2, respectively.
  • Hydraulic lifting cylinders of work machines when under load, can be lowered without additional energy supply, it being common to use both the piston side, i.e. in the pressure cylinder as well as on the rod side, i.e. in the suction cylinder room to carry out an oil filling.
  • Another solution is to connect the suction side of the cylinder to the tank so that the oil is sucked out of the tank from the suction side with the disadvantage that the line resistance between the cylinder and the tank must be overcome, resulting in an incomplete filling of the Cylinder can lead. This is countered by throttling in the tank return, which, however, generate heat that must be dissipated by cooling.
  • the requirement is to be able to lower the cylinders in a controlled manner without supplying energy, i.e. to use the energy of the hydraulic oil flowing from the stroke side to fill the suction side while avoiding throttles.
  • it is known to pass the pressurized, flowing hydraulic oil through a control element on the suction side of the cylinder, for example a separate lowering valve being provided between the cylinder and the main control valve, which is actuated during the lowering process instead of the main slide in order to reduce the required partial quantity to the To direct suction side of the cylinder, while the remaining amount can flow into the tank bypassing the main slide.
  • a further solution which consists in designing the main control slide for the lifting cylinder as a hollow piston, which in the lowered position creates a transition from the pressure side to the suction side of the cylinder, a check valve being arranged in the hollow piston and interrupting the connection during normal operation.
  • the production of such a hollow piston as a control piston in the main control slide is complex, the corresponding
  • the lowering circuit under gravity has the disadvantage that no additional force can be applied in the lowering direction by the lifting cylinder. In order to achieve an effect in the lowering direction, the lowering circuit must be switched off under gravity.
  • the object of the invention is to provide a procedure or a device which, when the control slide is set, fills the suction space of the cylinder sufficiently under all pressure conditions during the lowering process, a switchover to normal operation of the cylinder being carried out automatically, as soon as an additional cylinder force in the lowering direction is required.
  • a distribution channel is acted upon by the hydraulic pump in the control element, the pressure cylinder space or the suction cylinder space being switched on via a control piston,
  • control element provides a distributor channel which can be acted upon by the hydraulic pump and has two output channels which can be switched on and off via a control piston and which have connecting lines to the pressure cylinder chamber or suction cylinder chamber of the lifting cylinder, a check valve being provided between the channel and the distributor channel , a check valve influencing the pump inflow is provided in the distributor channel, a pressure sensor and a switch which can be activated by it for actuating a hydraulic valve for actuating the check valve is provided between the channel and the pressure cylinder space.
  • the check valve enables the pump to act upon it, which can act in the lowering direction. If the control piston is switched in the control element, the pump can then act in the stroke direction while acting on the pressure chamber.
  • the control valve is switched so that the hydraulic fluid closes the shut-off valve in the pump distribution channel and thus blocks the inflow of hydraulic oil from the pump, so that the hydraulic oil from the pressure cylinder chamber of the cylinder flows into the suction cylinder chamber via the check valve, excess oil possibly being returned to the tank.
  • control grooves on the control edges of the control piston, the inflow and outflow of both the lifting and the suction side of the cylinder are provided control grooves, the grooves on the lifting and the suction side of the area ratio of the lifting and suction side of the cylinder.
  • a practical and compact design also results in the check valve forming an integral unit with a secondary pressure limiting valve.
  • the invention also enables the use of two pumps, in which case it is expedient to provide at least one controlled check valve and one controlled check valve in the system.
  • La and lb a first embodiment of the invention with the "lowering" position of some device elements in Fig. La and the "lifting" position of some device elements in Fig. Lb,
  • Fig. 2 shows a modified embodiment of the
  • Fig. 3 shows an example with two pumps and in
  • Fig. 4 is an enlarged view of a built-in secondary protection with an integrated check valve.
  • the device generally designated 1 in the figures to control the movement of a lifting cylinder denoted by 2 is partly symbolic and otherwise shown in section in the figures and essentially consists of a control element 3 with a control piston 4 which can be displaced therein, via which different channels, which are described in more detail below, are opened, can be closed or connected to each other.
  • a distribution channel 5 which is approximately U-shaped in cross section, is provided, which is acted upon approximately symmetrically by a pump channel 6, to which a hydraulic oil pump 7 is connected.
  • a check valve 8 is provided approximately centrally, which can be connected to the pump 7 via a switching valve by means of a pump inflow line 10.
  • the cylinder 2 has a suction chamber denoted by 11 and a pressure chamber denoted by 12, defined by an externally applied load (arrow P), which via lines with a pressure channel 13 and a suction channel 14 in the control element defined in the same way according to the aforementioned pressure definition 3 are connected, the pressure channel 13 and the suction channel 14 being arranged parallel to the two partial arms of the pump distributor channel 5 and all of these channels being able to be folded in or out via the control piston 4. Hydraulic fluid can flow from there into the distribution channel 5 via a check valve within a secondary safety device 16, which is shown enlarged in FIG. 4, at a sufficiently high pressure in the channel 13, which is described in more detail below.
  • the device 1, i.e. the control element 3, in the axis of the control piston 4, has a control connection 17 at one end, via which, when pressure is applied, the control piston 4 can be moved against a spring 18 which is accommodated within a spring cap 19.
  • the pressure in the pressure cylinder chamber 12, or in the line leading from it to the pressure channel 13, can be measured via a pressure sensor 20.
  • a switch 22 can be activated via a line 21 from the spring cap 19, which in turn switches the valve 9 in connection with the pressure sensor 20.
  • two further parallel tank channels 23 and 24 are provided in the control element 3, each of which is acted upon by a secondary safeguard 16 and on the other hand form the feed lines to the tank denoted by 25 to ensure an overflow depending on the switching process.
  • a connection to the tank channel 23 is established by the displacement of the control slide piston 4 via the control groove 26. Since the pressures in the channels 5 and 13 are the same when the check valve 15 is open and thus also at the control grooves 26 and 27, the design of the control grooves 26 and 27 can be designed so that the Suction chamber 11 of the cylinder 2, the required amount of hydraulic oil is provided under all control piston positions and pressure ratios, while the remaining amount is supplied to the tank 25. The quantitative ratio of the hydraulic oil flowing out to the tank 25 and the suction chamber 11 of the cylinder 2 remains constant. The flow of the hydraulic oil from the cylinder space 12 to the cylinder space 11 is indicated by dotted lines.
  • the pump 7 can be controlled for zero delivery or can be directed to other consumers by means of suitable switching means.
  • the distribution channel 5 is depressurized and the shut-off valve 8 closes automatically in this case too.
  • the pressure in the cylinder space 12 will be in the region of zero.
  • the pressure sensor 20 determines this state and relieves the check valve 8 of the pump pressure and thus produces normal operation for the lowering process.
  • the switch 22 interrupts the signal from the pressure sensor 20 to the valve 9, the check valve 8 is depressurized and can open.
  • the switch 22 is switched by the control signal for the "lifting" (FIG. 1b), which is shown here as an example via the line device 21 is removed from the spring cap 19.
  • the flow of hydraulic oil during lifting is also indicated by dotted lines in FIG. 1b.
  • a check valve 29 can be provided instead of a controlled shut-off valve.
  • This version with check valve 29 can be used in all systems in which the pump flow to channel 5 is interrupted when the lowering process for cylinder 2 is switched on.
  • FIG. 3 A third embodiment of the invention is shown in FIG. 3.
  • Two pumps 7a and 7b are introduced into the control slide, the pump 7a being provided only for lowering when the regenerative circuit is switched off and pumps 7a and 7b for lifting.
  • the pump pressure of pumps 7a is switched to valve 8a via valve 9.
  • the pump 7a is switched off when lowering by other consumers or is depressurized switches, so that the check valve is provided for this circuit.
  • valve blocks for working machines have secondary safeguards 16.
  • An advantageous and economically more favorable embodiment is if the check valve 15 is arranged in the housing of the secondary safeguards 16 such that the check valve 15 connects the channel 13 to the distributor channel 5.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Operation Control Of Excavators (AREA)
  • Servomotors (AREA)

Abstract

The invention relates to a method and device for controlling a lift cylinder (2) of working machines, whereby as the lift cylinder lowers, the hydraulic oil is forced out of the pressure cylinder space (12) via a control element (3) into the suction cylinder space (11) by means of an external force. The aim of the invention is to enable an automatic switching over to the normal operation and into an operational state that permits an additional force to be exerted in a vertical direction. This is achieved, in particular, in that with a first predetermined force, the hydraulic oil coming from the pressure space (12) is forced via a check valve (15) into the control element (3) via the distribution channel (5) subjected to the action of the hydraulic pump (7) and is forced via said distribution channel into the suction cylinder space (11). The inflow of the hydraulic pump (7) is closed by a pressure-controlled stop valve (8), whereby this stop valve (8) opens during a fall in pressure and closes the check valve (15) in order to be able to exert an additional force onto the suction cylinder space (11) by means of the pump (7).

Description

'Verfahren und Vorrichtung zur Steuerung eines Hubzylinders insbesondere von Arbeitsmaschinen' 'Method and device for controlling a lifting cylinder, in particular of working machines'
Die Erfindung richtet sich auf ein Verfahren und eine Vorrichtung zur Steuerung eines Hubzylinders der im Anspruch 1 bzw. 2 angegebenen Gattung.The invention is directed to a method and a device for controlling a lifting cylinder of the type specified in claims 1 and 2, respectively.
Hydraulische Hubzylinder von Arbeitsmaschinen können, wenn sie unter Last stehen, ohne zusätzliche Energiezufuhr abgesenkt werden, wobei es üblich ist, sowohl auf der Kolbenseite, d.h. im Druckzylinder-, wie auch auf der Stangenseite, d.h. im Saugzylinderraum, eine Ölfüllung vorzunehmen.Hydraulic lifting cylinders of work machines, when under load, can be lowered without additional energy supply, it being common to use both the piston side, i.e. in the pressure cylinder as well as on the rod side, i.e. in the suction cylinder room to carry out an oil filling.
Es ist bei Hubzylindern von Arbeitsmaschinen bekannt, diese dadurch abzusenken, daß man das von der Last ausgeschobene Drucköl durch eine Steuereinheit oder frei einem Tank zuleitet, während die Hydraulikpumpe Hydraulikol auf die Saugseite des Zylinders fördert, um Kavitation zu vermeiden. Dabei ist es nachteilig, daß zur Füllung der Saugseite zusätzliche Energie aufgewandt werden muß.It is known for lifting cylinders of work machines to lower them by supplying the pressure oil pushed out by the load through a control unit or freely to a tank, while the hydraulic pump delivers hydraulic oil to the suction side of the cylinder in order to avoid cavitation. It is disadvantageous that additional energy has to be used to fill the suction side.
Eine andere Lösung besteht darin, die Saugseite des Zylinders mit dem Tank zu verbinden, so daß das Öl von der Saugseite aus dem Tank angesogen wird mit dem Nachteil, daß die Leitungswiderstände zwischen Zylinder und Tank überwunden werden müssen, was zu einer unvollständigen Füllung des Zylinders führen kann. Dem begegnet man durch Drosseln im Tankrücklauf, die allerdings Wärme erzeugen, die durch Kühlung abgeführt werden muß.Another solution is to connect the suction side of the cylinder to the tank so that the oil is sucked out of the tank from the suction side with the disadvantage that the line resistance between the cylinder and the tank must be overcome, resulting in an incomplete filling of the Cylinder can lead. This is countered by throttling in the tank return, which, however, generate heat that must be dissipated by cooling.
Aus Gründen der Energieeinsparung besteht die Forderung darin, die Zylinder ohne Zufuhr von Energie gesteuert absenken zu können, d.h. die Energie des von der Hubseite abfließenden Hydrauliköls zur Füllung der Saugseite zu nutzen unter Vermeidung von Drosseln. Dazu ist es bekannt, das unter Druck stehende, abfließende Hydraulikol durch ein Steuerelement auf die Saugseite des Zylinders zu leiten, wobei beispielsweise ein gesondertes Senkventil zwischen Zylinder und Hauptsteuerventil vorgesehen ist, das beim Senkvorgang anstelle des Hauptschiebers betätigt wird, um die erforderliche Teilmenge auf die Saugseite des Zylinders zu leiten, während die Restmenge unter Umgehung des Hauptschiebers in den Tank abfließen kann.For energy saving reasons, the requirement is to be able to lower the cylinders in a controlled manner without supplying energy, i.e. to use the energy of the hydraulic oil flowing from the stroke side to fill the suction side while avoiding throttles. For this purpose, it is known to pass the pressurized, flowing hydraulic oil through a control element on the suction side of the cylinder, for example a separate lowering valve being provided between the cylinder and the main control valve, which is actuated during the lowering process instead of the main slide in order to reduce the required partial quantity to the To direct suction side of the cylinder, while the remaining amount can flow into the tank bypassing the main slide.
Darüber hinaus ist eine weitere Lösung bekannt, die darin besteht, den Hauptsteuerschieber für den Hubzylinder als Hohlkolben auszubilden, der in der Senkposition eine Überleitung von der Druckseite zur Saugseite des Zylinders herstellt, wobei im Hohlkolben ein Rückschlagventil angeordnet ist und die Verbindung bei Normalbetrieb unterbricht . Die Herstellung eines derartigen Hohlkolbens als Steuerkolben im Hauptsteuerschieber ist aufwendig, wobei die entspre- chende Schaltung zum Senken unter Schwerkraft den Nachteil hat, daß durch den Hubzylinder keine zusätzliche Kraft in Senkrichtung aufgebracht werden kann. Um auch in Senkrichtung eine Wirkung zu erreichen, muß die Schaltung zum Senken unter Schwerkraft ausgeschaltet werden.In addition, a further solution is known, which consists in designing the main control slide for the lifting cylinder as a hollow piston, which in the lowered position creates a transition from the pressure side to the suction side of the cylinder, a check valve being arranged in the hollow piston and interrupting the connection during normal operation. The production of such a hollow piston as a control piston in the main control slide is complex, the corresponding The lowering circuit under gravity has the disadvantage that no additional force can be applied in the lowering direction by the lifting cylinder. In order to achieve an effect in the lowering direction, the lowering circuit must be switched off under gravity.
Gegenüber den oben beschriebenen bekannten Lösungen besteht die Aufgabe der Erfindung darin, eine Verfahrensweise bzw. eine Vorrichtung zu schaffen, die unter Einstellung des Steuerschiebers unter allen Druckverhältnissen beim Senkvorgang den Saugraum des Zylinders ausreichend füllt, wobei automatisch eine Umschaltung auf Normalbetrieb des Zylinders vorgenommen wird, sobald eine zusätzliche Zylinderkraft in Senkrichtung benötigt wird.Compared to the known solutions described above, the object of the invention is to provide a procedure or a device which, when the control slide is set, fills the suction space of the cylinder sufficiently under all pressure conditions during the lowering process, a switchover to normal operation of the cylinder being carried out automatically, as soon as an additional cylinder force in the lowering direction is required.
Mit einem Verfahren der eingangs bezeichneten Art wird diese Aufgabe gemäß der Erfindung dadurch gelöst,With a method of the type described in the introduction, this object is achieved according to the invention in that
- daß von der Hydraulikpumpe im Steuerelement ein Verteilerkanal beaufschlagt wird, wobei über einen Steuerkolben der Druckzylinderraum oder der Saugzylinderraum zugeschaltet wird,a distribution channel is acted upon by the hydraulic pump in the control element, the pressure cylinder space or the suction cylinder space being switched on via a control piston,
- daß bei einem ersten vorbestimmten, durch die externe Kraft/Last (P) bewirkten Druck im Zylinderraum dieser über ein Rückschlagventil mit diesem Verteilerkanal verbunden und über ein von einem Drucksensor beeinflußbares Sperrventil der Zufluß der Pumpe zum Verteilerkanal ge- sperrt wird, wobei dem Kanal der Saugzylinderraum zugeschaltet ist, und - daß bei Erreichen eines zweiten vorbestimmten Druckes das Rückschlagventil schließt und das Sperrventil, und damit der Zufluß der Hydraulikpumpe zum Verteilerkanal zur Aufbringung einer zusätzlichen Kraft im Saugzylinderraum geöffnet wird.- That at a first predetermined pressure caused by the external force / load (P) in the cylinder space this is connected via a check valve to this distribution channel and via a check valve which can be influenced by a pressure sensor, the inflow of the pump to the distribution channel. is blocked, the channel of the suction cylinder space being switched on, and - that when a second predetermined pressure is reached, the check valve closes and the shut-off valve, and thus the inflow of the hydraulic pump to the distribution channel, is opened to apply an additional force in the suction cylinder space.
Vorrichtungsmäßig wird die oben angegebene Aufgabe dadurch gelöst, daß im Steuerelement ein von der Hydraulikpumpe beaufschlagbarer Verteilerkanal mit zwei über einen Steuerkolben zu- und abschaltbaren Ausgangskanälen mit Verbindungsleitungen zu dem Druckzylinderraum bzw. Saugzylinderraum des Hubzylinders vorgesehen ist, wobei zwischen dem Kanal und dem Verteilerkanal ein Rückschlagventil , im Verteilerkanal ein den Pumpenzufluß beeinflussendes Sperrventil, zwischen Kanal und Druckzylinderraum ein Drucksensor sowie ein davon aktivierbarer Schalter zur Betätigung eines Hydraulikventiles zur Betätigung des Sperrventiles vorgesehen ist.In terms of the device, the above-mentioned object is achieved in that the control element provides a distributor channel which can be acted upon by the hydraulic pump and has two output channels which can be switched on and off via a control piston and which have connecting lines to the pressure cylinder chamber or suction cylinder chamber of the lifting cylinder, a check valve being provided between the channel and the distributor channel , a check valve influencing the pump inflow is provided in the distributor channel, a pressure sensor and a switch which can be activated by it for actuating a hydraulic valve for actuating the check valve is provided between the channel and the pressure cylinder space.
Erkennbar ist es durch die erfindungsgemäße Verfahrensweise möglich, über das Steuerelement das vom Druckraum des Zylinders kommende Öl zur Saugseite zu leiten, wobei die Druckkontrolle im Druckraum sowie die entsprechende Einstellung des Rückschlagventiles sowie die Schaltung des Steuerventiles eine Absenkung ohne Aufbringung einer äußeren Kraft gewährleistet.It can be seen through the procedure according to the invention that the oil coming from the pressure chamber of the cylinder is passed to the suction side via the control element, the pressure control in the pressure chamber and the corresponding setting of the check valve and the switching of the Control valve ensures a lowering without applying any external force.
Besonders zweckmäßig ist dabei, daß beispielsweise bei vollständigem Absenken des Arbeitgsgerätes über den Hubzylinder sich der Druck im Druckraum des Zylinders verringert bzw. vollständig dem Systemdruck anpaßt, wobei das Rückschlagventil schließt und ggf. das Sperrventil geöffnet werden kann. Dies ist auch problemlos beim Absenken unter Druck möglich, hier wird über das Sperrventil die Beaufschlagung durch die Pumpe ermöglicht, die in Absenkrichtung wirken kann. Wird der Steuerkolben im Steuerelement geschaltet, kann dann die Pumpe in Hubrichtung unter Beaufschlagung des Druckraumes wirken.It is particularly expedient that, for example, when the implement is completely lowered via the lifting cylinder, the pressure in the pressure chamber of the cylinder is reduced or completely adapts to the system pressure, the check valve closing and the check valve possibly being opened. This is also possible without problems when lowering under pressure. Here, the check valve enables the pump to act upon it, which can act in the lowering direction. If the control piston is switched in the control element, the pump can then act in the stroke direction while acting on the pressure chamber.
Wird beispielsweise durch die äußere Kraft ein Druck von mehr als 20 bar an den Druckschalter gemeldet, wird das Steuerventil so geschaltet, daß die Hydraulikflüssigkeit das Sperrventil im Pumpverteilerkanal schließt und damit den Zufluß von Hydraulikol von der Pumpe sperrt, so daß das Hydraulikol aus dem Druckzylinderraum des Zylinders über das Rückschlagventil in den Saugzylinderraum strömt, wobei überschüssiges Öl ggf. in den Tank zurückgeleitet werden kann.If, for example, a pressure of more than 20 bar is reported to the pressure switch by the external force, the control valve is switched so that the hydraulic fluid closes the shut-off valve in the pump distribution channel and thus blocks the inflow of hydraulic oil from the pump, so that the hydraulic oil from the pressure cylinder chamber of the cylinder flows into the suction cylinder chamber via the check valve, excess oil possibly being returned to the tank.
Sinkt der Druck beispielsweise durch Absetzen der äußeren Last im Druckzylinderraum ab, schließt das Rückschlagventil. Automatisch wird über den Drucksensor ein Steuersignal auf das Schaltventil gegeben, das schaltet und damit das Sperrventil drucklos macht, so daß dieses automatisch öffnet und den Zufluß des Hydrauliköls über die Pumpe auf die Saugseite des Zylinders ermöglicht, so daß ein Druck auf den Zylinder in Absenkrichtung möglich gemacht wird.For example, if the pressure drops, the pressure drops Check valve closes load in the pressure cylinder chamber. A control signal is automatically given to the switching valve via the pressure sensor, which switches and thus depressurizes the shut-off valve so that it opens automatically and allows the hydraulic oil to flow via the pump to the suction side of the cylinder, so that pressure is applied to the cylinder in the lowering direction is made possible.
Soll gehoben werden, wird die Steuerseite des Kolbens entlastet, so daß dieser federbeaufschlagte Kolben faltet, womit der Zufluß des Hydrauliköls zur Druckseite des Kolbens geöffnet wird.If lifting is to take place, the control side of the piston is relieved, so that this spring-loaded piston folds, which opens the inflow of the hydraulic oil to the pressure side of the piston.
Weitere Ausgestaltungen der Erfindung ergeben sich aus den Unteransprüchen .Further embodiments of the invention result from the subclaims.
Besonders vorteilhaft ist beispielsweise, daß an den Steuerkanten des Steuerkolbens, dem Zu- bzw. Abfluß sowohl der Hub- als auch der Saugseite des Zylinders freigebende Steuernuten vorgesehen sind, wobei die Nuten auf der Hub- und der Saugseite dem Flächenverhältnis der Hub- und Saugseite des Zylinders entsprechen.It is particularly advantageous, for example, that on the control edges of the control piston, the inflow and outflow of both the lifting and the suction side of the cylinder are provided control grooves, the grooves on the lifting and the suction side of the area ratio of the lifting and suction side of the cylinder.
Eine zweckmäßige und kompakte Bauweise ergibt sich darüber hinaus, daß das Rückschlagventil eine integrale Einheit mit einem Sekundärdruck-Begrenzungsventil bildet. Die Erfindung ermöglicht auch den Einsatz zweier Pumpen, wobei es dann zweckmäßig ist, im System wenigstens ein gesteuertes Sperr- und ein gesteuertes Rückschlagventil vorzusehen.A practical and compact design also results in the check valve forming an integral unit with a secondary pressure limiting valve. The invention also enables the use of two pumps, in which case it is expedient to provide at least one controlled check valve and one controlled check valve in the system.
Weitere Einzelheiten, Merkmale und Vorteile der Erfindung ergeben sich aufgrund der nachfolgenden Beschreibung sowie anhand der Zeichnung. Diese zeigt in denFurther details, features and advantages of the invention result from the following description and from the drawing. This shows in the
Fig. la und lb ein erstes Ausführungsbeispiel der Erfindung mit der Position "Senken" einiger Vorrichtungselemente in Fig. la und der Position "Heben" einiger Vorrichtungselemente in Fig. lb,La and lb a first embodiment of the invention with the "lowering" position of some device elements in Fig. La and the "lifting" position of some device elements in Fig. Lb,
Fig. 2 ein abgewandeltes Ausführungsbeispiel derFig. 2 shows a modified embodiment of the
Vorrichtung gemäß Fig. 1,1,
Fig. 3 ein Beispiel mit zwei Pumpen sowie inFig. 3 shows an example with two pumps and in
Fig. 4 eine vergrößerte Darstellung einer eingebauten Sekundärabsicherung mit integriertem Rückschlagventil .Fig. 4 is an enlarged view of a built-in secondary protection with an integrated check valve.
Die in den Figuren allgemein mit 1 bezeichnete Vorrichtung zur Steuerung der Bewegung eines mit 2 bezeichneten Hubzylinders ist zum Teil symbolisch und ansonsten in den Figuren im Schnitt gezeichnet und besteht im wesentlichen aus einem Steuerelement 3 mit einem darin verschiebbaren Steuerkolben 4, über den unterschiedliche Kanäle, die weiter unten näher beschrieben werden, geöffnet, geschlossen bzw. miteinander verbunden werden können.The device generally designated 1 in the figures to control the movement of a lifting cylinder denoted by 2 is partly symbolic and otherwise shown in section in the figures and essentially consists of a control element 3 with a control piston 4 which can be displaced therein, via which different channels, which are described in more detail below, are opened, can be closed or connected to each other.
Im Steuerelement 3 ist im Beispiel der Fig. 1 ein sich querschnittlich etwa U-förmig darstellender Verteilerkanal 5 vorgesehen, der etwa symmetrisch von einem Pumpkanal 6 beaufschlagt ist, an dem eine Hydraulikölpumpe 7 angeschlossen ist. Zur Absperrung des Zuflusses über den Pumpkanal 6 zum Verteilerkanal 5 ist etwa zentrisch ein Sperrventil 8 vorgesehen, das über ein Schaltventil mittels einer Pumpenzuflußleitung 10 mit der Pumpe 7 verbindbar ist.In the control element 3 in the example of FIG. 1, a distribution channel 5, which is approximately U-shaped in cross section, is provided, which is acted upon approximately symmetrically by a pump channel 6, to which a hydraulic oil pump 7 is connected. To shut off the inflow via the pump channel 6 to the distributor channel 5, a check valve 8 is provided approximately centrally, which can be connected to the pump 7 via a switching valve by means of a pump inflow line 10.
Der Zylinder 2 weist einen mit 11 bezeichneten Saugraum und mit 12 bezeichneten Druckraum, definiert durch eine von außen anliegende Last (Pfeil P), auf, die über Leitungen mit einem nach der vorgenannten Druckdefinition in gleicher Weise definierten Druckkanal 13 und einem Saugkanal 14 im Steuerelement 3 verbunden sind, wobei der Druckkanal 13 und der Saugkanal 14 parallel zu den beiden Teilarmen des Pum- penverteilerkanales 5 angeordnet und alle diese Kanäle über den Steuerkolben 4 zu- bzw. wegfaltbar sind. Über ein mit 15 bezeichnetes und in Fig. 4 vergrößert wiedergegebenes Rückschlagventil innerhalb einer Sekundärabsicherung 16 kann bei ausreichend hohem Druck im Kanal 13 Hy- draulikfluid von dort in den Verteilerkanal 5 fließen, was weiter unten näher beschrieben ist.The cylinder 2 has a suction chamber denoted by 11 and a pressure chamber denoted by 12, defined by an externally applied load (arrow P), which via lines with a pressure channel 13 and a suction channel 14 in the control element defined in the same way according to the aforementioned pressure definition 3 are connected, the pressure channel 13 and the suction channel 14 being arranged parallel to the two partial arms of the pump distributor channel 5 and all of these channels being able to be folded in or out via the control piston 4. Hydraulic fluid can flow from there into the distribution channel 5 via a check valve within a secondary safety device 16, which is shown enlarged in FIG. 4, at a sufficiently high pressure in the channel 13, which is described in more detail below.
Neben den beschriebenen Elementen weist die Vorrichtung 1, d.h. das Steuerelement 3, in der Achse des Steuerkolbens 4 an einem Ende einen Steueranschluß 17 auf, über den bei Druckaufbringung der Steuerkolben 4 gegen eine Feder 18 verschoben werden kann, die innerhalb einer Federkappe 19 untergebracht ist .In addition to the elements described, the device 1, i.e. the control element 3, in the axis of the control piston 4, has a control connection 17 at one end, via which, when pressure is applied, the control piston 4 can be moved against a spring 18 which is accommodated within a spring cap 19.
Der Druck im Druckzylinderraum 12, bzw. in der davon zum Druckkanal 13 führenden Leitung, ist über einen Drucksensor 20 meßbar. Über eine Leitung 21 aus der Federkappe 19 ist ein Schalter 22 aktivierbar, der wiederum in Verbindung mit dem Drucksensor 20 das Ventil 9 schaltet. Neben dem doppelt wirkenden Verteilerkanal 5 und dem Druckkanal 13 sowie dem Saugkanal 14 sind im Steuerelement 3 zwei weitere parallele Tankkanäle 23 bzw. 24 vorgesehen, die zum einen von je einer Sekundärabsicherung 16 beaufschlagt sind und zum anderen die Zuleitungen zu den mit 25 bezeichneten Tank bilden, um einen Überlauf je nach Schaltvorgang zu gewährleisten.The pressure in the pressure cylinder chamber 12, or in the line leading from it to the pressure channel 13, can be measured via a pressure sensor 20. A switch 22 can be activated via a line 21 from the spring cap 19, which in turn switches the valve 9 in connection with the pressure sensor 20. In addition to the double-acting distribution channel 5 and the pressure channel 13 and the suction channel 14, two further parallel tank channels 23 and 24 are provided in the control element 3, each of which is acted upon by a secondary safeguard 16 and on the other hand form the feed lines to the tank denoted by 25 to ensure an overflow depending on the switching process.
Um einen entsprechenden Durchfluß zu ermöglichen, weist der Steuerkolben 4 an den entsprechenden Stellen Steuernuten 26 bzw. 27 auf.In order to enable a corresponding flow, the Control piston 4 at the corresponding points control grooves 26 and 27 respectively.
Die Funktionsweise der Vorrichtung 1 sei nachfolgend anhand der Beispiele der Fig. la und lb näher erläutert:The mode of operation of the device 1 is explained in more detail below with reference to the examples in FIGS. 1a and 1b:
Wird über den Steueranschluß 17 der Kolben des Steuerschiebers auf "Senken" (Fig. 1) geschaltet, so bewegt sich der Kolben 4 in Richtung der Federkappe 19. Die äußere Last P erzeugt in dem Zylinder 2 in dem Zylinderraum 12 einen Druck und die Druckflüssigkeit des Zylinderraumes 12 fließt über den Kanal 13, das Rückschlagventil 15, welches in diesem Beispiel in der Patrone der Sekundärabsicherung 16 eingebaut ist (Fig. 4), in den Verteilerkanal 5. Über die Steuernuten 27 gelangt die Druckflüssigkeit in den Kanal 14, der zu dem Saugraum 11 des Zylinders 2 führt. Der Druck im Zylinderraum 12 schaltet ferner den Drucksensor 20, der das Ventil 9 betätigt und damit den Druck der Pumpe 7 auf das Sperrventil 8 leitet, das somit schließt.If the piston of the control slide is switched to "lower" (FIG. 1) via the control connection 17, the piston 4 moves in the direction of the spring cap 19. The external load P generates a pressure and the pressure fluid in the cylinder 2 in the cylinder chamber 12 of the cylinder chamber 12 flows via the channel 13, the check valve 15, which in this example is installed in the cartridge of the secondary safeguard 16 (FIG. 4), into the distributor channel 5. Via the control grooves 27, the pressure fluid reaches the channel 14, which leads to the suction chamber 11 of the cylinder 2 leads. The pressure in the cylinder chamber 12 also switches the pressure sensor 20, which actuates the valve 9 and thus directs the pressure of the pump 7 to the check valve 8, which thus closes.
Gleichzeitig wird durch die Verschiebung des Steuerschiebekolbens 4 über die Steuernut 26 eine Verbindung zu dem Tankkanal 23 hergestellt. Da die Drücke in den Kanälen 5 und 13 bei geöffnetem Rückschlagventil 15 gleich sind und somit auch an den Steuernuten 26 und 27, kann die Ausbildung der Steuernuten 26 und 27 so gestaltet werden, daß dem Saugraum 11 des Zylinders 2 unter allen Steuerkolbenstellungen und Druckverhältnissen die erforderliche Menge an Hydraulikol zur Verfügung gestellt wird, während die Restmenge dem Tank 25 zugeführt wird. Das Mengenverhältnis des zum Tank 25 und zum Saugraum 11 des Zylinders 2 abfließenden Hydrauliköls bleibt dabei konstant. Der Fluß des Hydrauliköls vom Zylinderraum 12 zum Zylinderraum 11 ist punktiert angedeutet .At the same time, a connection to the tank channel 23 is established by the displacement of the control slide piston 4 via the control groove 26. Since the pressures in the channels 5 and 13 are the same when the check valve 15 is open and thus also at the control grooves 26 and 27, the design of the control grooves 26 and 27 can be designed so that the Suction chamber 11 of the cylinder 2, the required amount of hydraulic oil is provided under all control piston positions and pressure ratios, while the remaining amount is supplied to the tank 25. The quantitative ratio of the hydraulic oil flowing out to the tank 25 and the suction chamber 11 of the cylinder 2 remains constant. The flow of the hydraulic oil from the cylinder space 12 to the cylinder space 11 is indicated by dotted lines.
Gleichzeitig mit dem Einschalten des Senkvorganges kann die Pumpe 7 auf Null-Förderung gesteuert werden oder durch geeignete Schaltmittel auf andere Verbraucher geleitet werden. Dadurch ist der Verteilerkanal 5 drucklos und das Sperrventil 8 schließt auch in diesem Fall selbsttätig.Simultaneously with the switching on of the lowering process, the pump 7 can be controlled for zero delivery or can be directed to other consumers by means of suitable switching means. As a result, the distribution channel 5 is depressurized and the shut-off valve 8 closes automatically in this case too.
Wird die Last P auf dem Boden abgesetzt, so wird der Druck im Zylinderraum 12 im Bereich von Null liegen. Der Drucksensor 20 ermittelt diesen Zustand und entlastet das Sperrventil 8 vom Pumpendruck und stellt damit für den Senkvorgang den Normalbetrieb her . Um für den Hubvorgang das Sperrventil 8 offen zu halten, unterbricht der Schalter 22 das Signal vom Drucksensor 20 zum Ventil 9, das Sperrventil 8 ist druckentlastet und kann öffnen.If the load P is deposited on the floor, the pressure in the cylinder space 12 will be in the region of zero. The pressure sensor 20 determines this state and relieves the check valve 8 of the pump pressure and thus produces normal operation for the lowering process. In order to keep the check valve 8 open for the lifting process, the switch 22 interrupts the signal from the pressure sensor 20 to the valve 9, the check valve 8 is depressurized and can open.
Der Schalter 22 wird von dem Steuersignal für das "Heben" (Fig. lb) geschaltet, das hier als Beispiel über die Lei- tung 21 aus der Federkappe 19 entnommen wird. Der Fluß des Hydrauliköls beim Heben ist in Fig. lb ebenfalls punktiert angedeutet. Durch diese erfindungsgemäße Anordnung ist eine Regenerativschaltung beim Senken unter Last gegeben, während die Funktionen "Senken" und "Heben" mit der Pumpe als Normalbetrieb sich automatisch einstellen.The switch 22 is switched by the control signal for the "lifting" (FIG. 1b), which is shown here as an example via the line device 21 is removed from the spring cap 19. The flow of hydraulic oil during lifting is also indicated by dotted lines in FIG. 1b. This arrangement according to the invention provides a regenerative circuit when lowering under load, while the functions "lowering" and "lifting" with the pump are set automatically as normal operation.
In einer zweiten Ausgestaltung der Erfindung gemäß Fig. 2 wird der Druck des Zylinderraumes 12 über das Ventil 9 über eine Leitung auf einen Pumpenregler 28 geschaltet und damit die Pumpe 7 auf Null-Förderung gestellt. In dieser Ausführung kann anstelle eines gesteuerten Sperrventils ein Rückschlagventil 29 vorgesehen werden. Diese Ausführung mit Rückschlagventil 29 kann bei allen Systemen verwendet werden, bei denen bei Einschaltung des Senkvorganges für den Zylinder 2 der Pumpenzufluß zum Kanal 5 unterbrochen ist.In a second embodiment of the invention according to FIG. 2, the pressure of the cylinder chamber 12 is switched via the valve 9 via a line to a pump controller 28 and the pump 7 is thus set to zero delivery. In this embodiment, a check valve 29 can be provided instead of a controlled shut-off valve. This version with check valve 29 can be used in all systems in which the pump flow to channel 5 is interrupted when the lowering process for cylinder 2 is switched on.
Eine dritte Ausgestaltung der Erfindung ist in Fig. 3 dargestellt. Dabei werden zwei Pumpen 7a und 7b in den Steuerschieber eingeleitet, wobei die Pumpe 7a nur für das Senken bei ausgeschalteter Regenerativschaltung und Pumpe 7a und 7b für das Heben vorgesehen sind. Dabei wird der Pumpendruck der Pumpen 7a über das Ventil 9 auf das Ventil 8a geschaltet. In diesem Beispiel ist die Pumpe 7a beim Senken durch andere Verbraucher abgeschaltet oder drucklos ge- schaltet, so daß für diesen Kreis das Rückschlagventil vorgesehen ist.A third embodiment of the invention is shown in FIG. 3. Two pumps 7a and 7b are introduced into the control slide, the pump 7a being provided only for lowering when the regenerative circuit is switched off and pumps 7a and 7b for lifting. The pump pressure of pumps 7a is switched to valve 8a via valve 9. In this example, the pump 7a is switched off when lowering by other consumers or is depressurized switches, so that the check valve is provided for this circuit.
In Fig. 4 ist eine vorteilhafte Anordnung des Rückschlagventils 15 dargestellt. Ventilblöcke für Arbeitsmaschinen verfügen über Sekundärsabsicherungen 16. Eine vorteilhafte und wirtschaftlich günstigere Ausführung ist, wenn das Rückschlagventil 15 in dem Gehäuse der Sekundär bsicherun- gen 16 so angeordnet ist, daß das Rückschlagventil 15 den Kanal 13 mit dem Verteilerkanal 5 verbindet. 4 shows an advantageous arrangement of the check valve 15. Valve blocks for working machines have secondary safeguards 16. An advantageous and economically more favorable embodiment is if the check valve 15 is arranged in the housing of the secondary safeguards 16 such that the check valve 15 connects the channel 13 to the distributor channel 5.

Claims

Patentansprüche : Claims:
1. Verfahren zur Steuerung eines Hubzylinders (2) von Arbeitsmaschinen, wie Baggern, Radladern od. dgl . , wobei der Hubzylinder (2) in Senkrichtung von einer externen Kraft (äußeren Last P) beaufschlagbar ist, wobei der Druckzylinderraum (12) und der Saugzylinderraum (11) des Hubzylinders (2) mit Druckflüssigkeit über eine diese beiden Räume (11, 12) miteinander verbindende Leitung mit einem darin vorgesehenen Steuerelement (3) beaufschlagt sind, wobei das Steuerelement (3) die Zu- bzw. Abflüsse der Zylinderräume (12,11) und den Überlauf in einen Tank (25) für das Arbeitsmedium über eine Hydraulikpumpe (7) steuert, dadurch gekennzeichnet, daß von der Hydraulikpumpe (7) im Steuerelement (3) ein Verteilerkanal (5) beaufschlagt wird, wobei über einen Steuerkolben (4) der Druckzylinderraum (12) oder der Saugzylinderraum (11) zugeschaltet wird, daß bei einem vorbestimmten, durch die externe Kraft/Last (P) bewirkten Druck im Zylinderraum (12) dieser über ein Rückschlagventil (15) mit diesem Verteilerkanal (5) verbunden und über ein von einem Drucksensor (20) beeinflußbares Sperrventil (8) der Zufluß der Pumpe (7) zum Verteilerkanal (5) gesperrt wird, wobei dem Kanal (5) der Saugzylinderraum (11) zugeschaltet ist, und daß bei Erreichen eines anderen vorbestimmten Druckes das Rückschlagventil (15) schließt und das Sperrventil (8) und damit der Zufluß der Hydraulikpumpe (7) zum Verteilerkanal (5) zur Aufbringung einer zusätzlichen Kraft im Saugzylinderraum (11) geöffnet wird.1. Method for controlling a lifting cylinder (2) of work machines such as excavators, wheel loaders or the like. The lifting cylinder (2) can be acted upon in the lowering direction by an external force (external load P), the pressure cylinder space (12) and the suction cylinder space (11) of the lifting cylinder (2) being pressurized with fluid via one of these two spaces (11, 12). interconnecting line are acted upon by a control element (3) provided therein, the control element (3) controlling the inflows and outflows of the cylinder spaces (12, 11) and the overflow into a tank (25) for the working medium via a hydraulic pump (7 ) controls, characterized in that the hydraulic pump (7) acts on a distributor channel (5) in the control element (3), the pressure cylinder chamber (12) or the suction cylinder chamber (11) being switched on via a control piston (4) that at one predetermined pressure caused by the external force / load (P) in the cylinder space (12), which is connected to this distribution channel (5) via a check valve (15) and via a pressure which can be influenced by a pressure sensor (20) rrventil (8) the inflow of the pump (7) to the distribution channel (5) is blocked, the channel (5) being connected to the suction cylinder space (11), and that when another predetermined pressure is reached, the check valve (15) closes and the shut-off valve (8) and thus the inflow of the hydraulic pump (7) to the distribution channel (5) is opened to apply an additional force in the suction cylinder space (11).
2. Vorrichtung (1) zur Steuerung eines Hubzylinders (2) von Arbeitsmaschinen, wie Baggern, Radladern od. dgl., wobei der Hubzylinder (2) in Senkrichtung von einer externen Kraft (äußeren Last P) beaufschlagbar ist, wobei der Druckzylinderraum (12) und der Saugzylinderraum (11) des Hubzylinders (2) mit Druckflüssigkeit über eine diese beiden Räume (11,12) miteinander verbindende Leitung mit einem darin vorgesehenen Steuerelement (3) beaufschlagt sind, wobei das Steuerelement (3) die Zu- bzw. Abflüsse der Zylinderräume (12,11) und den Überlauf in einen Tank (25) für das Arbeitsmedium über eine Hydraulikpumpe (7) steuert, dadurch gekennzeichnet, daß im Steuerelement (3) ein von der Hydraulikpumpe (7) beaufschlagbarer Verteilerkanal (5) mit zwei über einen Steuerkolben (4) zu- und abschaltbaren Ausgangskanälen (13,14) mit Verbindungsleitungen zu dem Druckzylinderraum (12) bzw. Saugzylinderraum (11) des Hubzylinders (2) vorgesehen ist, wobei zwischen dem Kanal (13) und dem Verteilerkanal (5) ein Rückschlagventil (15), im Verteilerkanal (5) ein den Pumpenzufluß beeinflussendes Sperrventil (8), zwischen Ka- nal (13) und Druckzylinderraum (12) ein Drucksensor (20) sowie ein davon aktivierbarer Schalter (22) zur Betätigung eines Hydraulikventiles (9) zur Betätigung des Sperrventiles (8) vorgesehen ist.2. Device (1) for controlling a lifting cylinder (2) of working machines, such as excavators, wheel loaders or the like. The lifting cylinder (2) can be acted upon in the lowering direction by an external force (external load P), the pressure cylinder space (12 ) and the suction cylinder chamber (11) of the lifting cylinder (2) is pressurized with hydraulic fluid via a line connecting these two chambers (11, 12) with a control element (3) provided therein, the control element (3) controlling the inflows and outflows controls the cylinder spaces (12, 11) and the overflow into a tank (25) for the working medium via a hydraulic pump (7), characterized in that in the control element (3) a distributor channel (5) which can be acted upon by the hydraulic pump (7) has two Via a control piston (4) connectable and disconnectable output channels (13, 14) with connecting lines to the pressure cylinder chamber (12) or suction cylinder chamber (11) of the lifting cylinder (2) is provided, with between the channel (13) and the vert rapid channel (5) a check valve (15), in the distribution channel (5) a check valve influencing the pump inflow (8), between the nal (13) and pressure cylinder chamber (12), a pressure sensor (20) and a switch (22) which can be activated to actuate a hydraulic valve (9) for actuating the check valve (8) is provided.
3. Vorrichtung nach Anspruch 2, dadurch gekennzeichnet, daß an den Steuerkanten des Steuerkolbens (4), dem Zu- bzw. Abfluß sowohl der Hub- als auch der Saugseite des Zylinders (2) freigebende Steuernuten (26,27) vorgesehen sind, wobei die Nuten auf der Hub- und der Saugseite dem Flächenverhältnis der Hub- und Saugseite des Zylinders (2) entsprechen.3. Apparatus according to claim 2, characterized in that on the control edges of the control piston (4), the inflow and outflow both the lifting and the suction side of the cylinder (2) releasing control grooves (26,27) are provided, wherein the grooves on the stroke and suction side correspond to the area ratio of the stroke and suction side of the cylinder (2).
4. Vorrichtung nach Anspruch 2 oder 3, dadurch gekennzeichnet, daß das Rückschlagventil (15) eine integrale Einheit mit einem Sekundärdruck-Begrenzungsventil (16) bildet.4. Apparatus according to claim 2 or 3, characterized in that the check valve (15) forms an integral unit with a secondary pressure limiting valve (16).
5. Vorrichtung nach Anspruch 2 oder einem der folgenden, dadurch gekennzeichnet, daß zwei Pumpen (7a, 7b) vorgesehen sind mit einem Rückschlagventil (15), einem weiteren Rückschlagventil (29) sowie einem druckbeaufschlagten Sperrventil (8a) im Steuerelement (3a) . 5. Apparatus according to claim 2 or one of the following, characterized in that two pumps (7a, 7b) are provided with a check valve (15), a further check valve (29) and a pressurized check valve (8a) in the control element (3a).
6. Vorrichtung nach Anspruch 2 oder einem der folgenden, dadurch gekennzeichnet, daß ein Pumpenregler (28) zur Regelung der Förderpumpe (7) in Abhängigkeit des Druckes im Druckraum (12) des Zylinders (2) vorgesehen ist.6. The device according to claim 2 or one of the following, characterized in that a pump controller (28) for controlling the feed pump (7) depending on the pressure in the pressure chamber (12) of the cylinder (2) is provided.
7. Vorrichtung nach Anspruch 2 oder einem der folgenden, dadurch gekennzeichnet, daß Steuernuten vorgesehen sind zur Verbindung des Druck- kanales (13) bzw. Saugkanales (14) mit zugeordneten Tankkanälen (16 bzw. 23) zur Hydrauliköl-Überschubableitung in den Hydrauliktank (25). 7. The device according to claim 2 or one of the following, characterized in that control grooves are provided for connecting the pressure channel (13) or suction channel (14) with assigned tank channels (16 or 23) for hydraulic oil overflow in the hydraulic tank ( 25).
EP01902390A 2000-02-04 2001-02-02 Method and device for controlling a lift cylinder, especially of working machines Expired - Lifetime EP1252449B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10004905 2000-02-04
DE10004905A DE10004905C2 (en) 2000-02-04 2000-02-04 Method and device for controlling a lifting cylinder, in particular of working machines
PCT/EP2001/001121 WO2001057405A1 (en) 2000-02-04 2001-02-02 Method and device for controlling a lift cylinder, especially of working machines

Publications (2)

Publication Number Publication Date
EP1252449A1 true EP1252449A1 (en) 2002-10-30
EP1252449B1 EP1252449B1 (en) 2004-08-25

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Application Number Title Priority Date Filing Date
EP01902390A Expired - Lifetime EP1252449B1 (en) 2000-02-04 2001-02-02 Method and device for controlling a lift cylinder, especially of working machines

Country Status (6)

Country Link
US (1) US6701823B2 (en)
EP (1) EP1252449B1 (en)
JP (1) JP4652655B2 (en)
KR (1) KR20020080338A (en)
DE (2) DE10004905C2 (en)
WO (1) WO2001057405A1 (en)

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Also Published As

Publication number Publication date
JP4652655B2 (en) 2011-03-16
EP1252449B1 (en) 2004-08-25
US20030000373A1 (en) 2003-01-02
DE10004905A1 (en) 2001-08-16
DE10004905C2 (en) 2002-10-24
US6701823B2 (en) 2004-03-09
KR20020080338A (en) 2002-10-23
WO2001057405A1 (en) 2001-08-09
JP2003521652A (en) 2003-07-15
DE50103395D1 (en) 2004-09-30

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