EP1515049B1 - Hydraulic control - Google Patents

Hydraulic control Download PDF

Info

Publication number
EP1515049B1
EP1515049B1 EP20040011284 EP04011284A EP1515049B1 EP 1515049 B1 EP1515049 B1 EP 1515049B1 EP 20040011284 EP20040011284 EP 20040011284 EP 04011284 A EP04011284 A EP 04011284A EP 1515049 B1 EP1515049 B1 EP 1515049B1
Authority
EP
European Patent Office
Prior art keywords
pressure
load pressure
pump
valves
load
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
EP20040011284
Other languages
German (de)
French (fr)
Other versions
EP1515049A1 (en
Inventor
Martin Dipl.-Ing. Heusser
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.)
Hawe Hydraulik GmbH and Co KG
Original Assignee
Hawe Hydraulik GmbH and Co KG
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 Hawe Hydraulik GmbH and Co KG filed Critical Hawe Hydraulik GmbH and Co KG
Publication of EP1515049A1 publication Critical patent/EP1515049A1/en
Application granted granted Critical
Publication of EP1515049B1 publication Critical patent/EP1515049B1/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/226—Safety arrangements, e.g. hydraulic driven fans, preventing cavitation, leakage, overheating
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2221—Control of flow rate; Load sensing arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/161—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load
    • F15B11/165—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors with sensing of servomotor demand or load for adjusting the pump output or bypass in response to demand
    • 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
    • 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
    • F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
    • F15B13/0416—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor with means or adapted for load sensing
    • F15B13/0417—Load sensing elements; Internal fluid connections therefor; Anti-saturation or pressure-compensation 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
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20538—Type of pump constant 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
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/20576—Systems with pumps with multiple pumps
    • F15B2211/20584—Combinations of pumps with high and low 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
    • F15B2211/3053—In combination with a pressure compensating valve
    • F15B2211/30535—In combination with a pressure compensating valve the pressure compensating valve is arranged between pressure source and directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/3056—Assemblies of multiple 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
    • F15B2211/3111—Neutral or centre positions the pump port being closed in the centre position, e.g. so-called closed centre
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3122—Special positions other than the pump port being connected to working ports or the working ports being connected to the return line
    • F15B2211/3127—Floating position connecting the working ports and the return line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3144—Directional control characterised by the positions of the valve element the positions being continuously variable, e.g. as realised by proportional 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
    • F15B2211/315—Directional control characterised by the connections of the valve or valves in the circuit
    • F15B2211/3157—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source, an output member and a return line
    • F15B2211/31576—Directional control characterised by the connections of the valve or valves in the circuit being connected to a pressure source, an output member and a return line having a single pressure source and a single 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
    • F15B2211/30—Directional control
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/321—Directional control characterised by the type of actuation mechanically
    • F15B2211/322—Directional control characterised by the type of actuation mechanically actuated by biasing means, e.g. spring-actuated
    • F15B2211/323—Directional control characterised by the type of actuation mechanically actuated by biasing means, e.g. spring-actuated the biasing means being adjustable
    • 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
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/321—Directional control characterised by the type of actuation mechanically
    • F15B2211/324—Directional control characterised by the type of actuation mechanically manually, e.g. by using a lever or pedal
    • 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
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/327—Directional control characterised by the type of actuation electrically or electronically
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/329—Directional 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
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40553—Flow control characterised by the type of flow control means or valve with pressure compensating valves
    • F15B2211/40561—Flow control characterised by the type of flow control means or valve with pressure compensating valves the pressure compensating valve arranged upstream of the flow control means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/41563—Flow control characterised by the connections of the flow control means in the circuit being connected to a pressure source and a return line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/45—Control of bleed-off flow, e.g. control of bypass flow to the return line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
    • F15B2211/50518—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using pressure relief 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
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50563—Pressure control characterised by the type of pressure control means the pressure control means controlling a differential pressure
    • F15B2211/50581—Pressure control characterised by the type of pressure control means the pressure control means controlling a differential pressure using counterbalance 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
    • F15B2211/50—Pressure control
    • F15B2211/52—Pressure control characterised by the type of actuation
    • F15B2211/528—Pressure 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
    • F15B2211/50—Pressure control
    • F15B2211/575—Pilot pressure 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
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/605—Load sensing circuits
    • F15B2211/6051—Load sensing circuits having valve means between output member and the load sensing circuit
    • F15B2211/6052—Load sensing circuits having valve means between output member and the load sensing circuit using 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
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/605—Load sensing circuits
    • F15B2211/6051—Load sensing circuits having valve means between output member and the load sensing circuit
    • F15B2211/6054—Load sensing circuits having valve means between output member and the load sensing circuit using shuttle 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
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/605—Load sensing circuits
    • F15B2211/6051—Load sensing circuits having valve means between output member and the load sensing circuit
    • F15B2211/6055—Load sensing circuits having valve means between output member and the load sensing circuit using pressure relief 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
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/615—Filtering means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders

Definitions

  • the invention relates to a hydraulic control specified in the preamble of claim 1 Art.
  • Such hydraulic controls are used in practice, inter alia, in skip loaders, i. in vehicles with several hydraulic loads, which can be controlled individually or partially overlapping.
  • the pressure supply takes place in such known from practice by prior use hydraulic control by means of a multi-stage fixed displacement pump via a single drive.
  • the power of the drive is limited.
  • the multi-stage constant pump is a two-stage or double constant-action pump, each pump stage of which supplies a single section of the consumer group with a specific flow rate, so that there is a two-circuit pressure supply system.
  • Each pump stage delivers to the tank via a flow regulator when there is no power requirement in the associated consumer section.
  • a load pressure limit can be set so that when operating loads in both sections, the power limit of the drive is not exceeded.
  • the invention has for its object to provide a hydraulic control of the type mentioned, in which the consumers can use a available from the pump stages, maximum flow greater than the flow rate of only one pump stage while avoiding pressure oscillations in the system.
  • the existing pump stages promote the single-circuit pressure supply system common to all consumers, the entire delivery rate from all pump stages is available for use by every consumer at least until the lower load pressure limit is reached. Since this combined delivery is actually used only to reach the lower load pressure limit for controlling one or more consumers, and the common drive of the multi-stage constant pump is not charged beyond its capacity limit. However, as soon as the lower load pressure limit is reached and the associated pump stage is switched to pressureless circulation, the delivery rate of the pump stage with the highest load pressure limit remains available in the single-circuit pressure supply system. Since then the decrease in power of at least one pump stage is reduced with lower load pressure limit, at least the highest load pressure limit of the then continue to Control used pump stage are optimally elevated.
  • a common load pressure signaling circuit is provided for all load pressure taps of the consumer group.
  • the pressure compensator drain valves are precontrolled against the supply pressure, which is tapped from the single-circuit pressure supply system. So that when a pump stage with lower load pressure limit works in the non-pressurized circulation, no pressure medium from the pump stage with the higher load pressure limit can flow, each set to a lower load pressure limit pump stage is secured by a check valve against the single-circuit pressure supply system.
  • the diaphragm is preset, which prevents the response of this safety valve and the load pressure for the other safety valve is reduced.
  • the hydraulic control adjusts automatically to the respective operating conditions, so that at least until the response of a safety valve, a combined maximum flow in the single-circuit pressure supply system of all consumers of the consumer group is available.
  • the power of the drive can be used predominantly for pumping at the pump level which is at the highest load pressure limit is set.
  • This pump stage is expediently designed with the highest flow rate.
  • the delivery rates of other pump stages are set in stages decreasing, whereby the respective set load pressure limits can also decrease stepwise with the decreasing flow rates. In this way, the already mentioned stair profile of the pressure / flow characteristics can be optimally adjusted.
  • only a two-stage or double-constant pump is provided whose pump stage flow rates are in a ratio of about 2: 1.
  • the load pressure limit for the pump stage with the highest flow rate is set approximately 50% higher than the load pressure limit of the other pump stage. For example, with a flow rate of a pump stage of about 77 l / min, the load pressure limit is set to about 300 bar, while in the pump stage with a flow rate of about 38.5 l / min, the load pressure limit is set to only about 200 bar.
  • FIG. 1 is a block diagram of a hydraulic control, as used for example in a skip loader for the hydraulic consumer.
  • a hydraulic control S shown in FIG. 1 is used to actuate a plurality of consumers of a consumer group, for the sake of simplicity, only two consumers V1 and V2 are indicated, although certainly further, not shown in Fig. 1 consumer provided and incorporated into the hydraulic control S. ,
  • each consumer V1, V2 is controlled by means of a directional control valve C1, C2 in its direction and speed.
  • the directional control valves C1, C2 are, for example, magnetically and manually operated proportional directional control valves Pressure pre-control and in each case at least one load pressure tap L for the load pressure of the consumer V1, V2.
  • the directional control valves C1, C2 are connected to a common single-circuit pressure supply system 3, 4, 5 and via a tank line 6 to a tank T.
  • a multi-stage fixed displacement pump P is provided, which is driven by a single drive A.
  • the flow rate Q1 is, for example, about 38.5 l / min, while the flow rate Q2 is 77 l / min, for example.
  • a common load pressure signaling circuit 8 is provided, to which the load pressure handles L of all directional control valves C1, C2 are connected, expediently via individual load pressure control line sections linking shuttle valves W.
  • Each pump stage P1, P2 is associated with a pressure compensator Ablouregelventil DW1, DW2 to the tank T, which is acted upon by a control spring F1, F2 in Schlulraum. Further, the closing control sides of the pressure compensator discharge control valves DW1, DW2 are connected to the common load pressure detecting circuit 8. For this purpose, branches off from a central shuttle valve W from a control line 9, in which a hydraulic damping device 10 is arranged, and leading to a branch 11.
  • the hydraulic damping device 10 includes a damping throttle 20 and two counter-bypass check valves 21, 22 arranged in opposite directions, of which at least the bypass check valve 22 which opens to the load pressure signaling circuit 8 can be spring-loaded (valve spring 23).
  • a control line 12 leads to the closing control side of the pressure compensator Ablassregelventils DW1 and the input of a safety valve 13 which is acted upon by a spring in the closing direction and pressure controlled in the opening direction from the control line 12.
  • a diaphragm B is provided upstream of the safety valve 13 and downstream of the branch 11, a diaphragm B is provided.
  • the safety valve 13 is set to a low load pressure limit, for example to 200 bar.
  • a control line 14 leads to a further safety valve 15, which functionally corresponds to the safety valve 13, and also to the closing control side of the other pressure compensator drain control valve DW2.
  • the safety valve 15 is set to a higher load pressure limit or to the highest load pressure limit, for example to about 300 bar.
  • the mentioned load pressure limits can be varied, for example, based on the safety valve springs.
  • no aperture is included in the control line 14.
  • a control line 16 branches off from the merge 3 to the pilot pressure side of the pressure compensator drain control valve DW1.
  • a diaphragm 17 is included.
  • the control line 16 could also be led to the control side of the other pressure compensator Ablassregelventil DW2.
  • a control line 18 branches off approximately in extension of the connection line 2 to the control side of the pressure compensator drain control valve DW2.
  • a diaphragm 19 is also included.
  • a load pressure corresponding to the existing load builds up in the load pressure reporting system 8.
  • This load pressure adjusts the two pressure compensator Ablassregelventile DW1, DW2 in the closing direction, such that the supply pressure in the single-circuit pressure supply system 3, 4, 5 each slightly higher than the required load pressure.
  • the combined delivery quantities Q1, Q2 of each consumer V1, V2 can be used in the single-circuit pressure supply system 3, 4, 5.
  • the highest load pressure is reported, so that the supply pressure increases accordingly.
  • the safety valve 13 is switched to passage and the control line 12 is relieved.
  • the pressure compensator Ablouregelventil DW1 is made to pass through the pressure in the control line 16, so that the flow rate Q1 flows into the tank T. Since the safety valve 15 does not respond at this lower load pressure limit, the single-circuit pressure supply system 3, 4, 5 continues to be supplied with the delivery rate Q2 of the other pump stage P2.
  • a check valve 7 is provided between the connecting line 1 and the junction 3, which blocks in the flow direction to the pressure compensator drain control valve DW1.
  • Each consumer V1, V2 can then continue to operate until reaching the highest load pressure limit of the safety valve 15 with the flow rate Q2, which, suitably, the flow rate Q2 and the highest load pressure limit are selected at the safety valve 15 so that upon reaching the highest load pressure limit of the drive A is not overloaded.
  • the hydraulic controller could include a multi-stage fixed displacement pump P having more than two pump stages. Then, in each case one pump stage with a low load pressure limit would have to be secured by a check valve corresponding to the check valve 7 with respect to a pump stage with a higher load pressure limit. Furthermore, each safety valve, which is set to a lower than the highest load pressure limit, would have to be secured by a diaphragm analogous to the diaphragm B, to prevent the relieved in response of the associated pressure compensator Abladedregelventils control pressure and the control pressure for the to a higher load pressure limit set safety valve could decrease.
  • the size of the diaphragm B is selected so that the diaphragm B allows less control pressure fluid to flow out, as the control pressure fluid flows from the load pressure reporting system 8.
  • the hydraulic damping device 10 is important because the damping throttle 20, although it is bypassable in both directions of flow through the respective check valve 21 or 22, quickly brings pressure oscillations in the control circuit to decay before they are transmitted via the pressure compensators DW1, DW2 in the working lines, and / or if such pressure oscillations have been transferred from the working lines or from the consumers into the control circuit.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Fluid-Pressure Circuits (AREA)

Description

Die Erfindung betrifft eine Hydrauliksteuerung der im Oberbegriff des Anspruchs 1 angegebenen Art.The invention relates to a hydraulic control specified in the preamble of claim 1 Art.

Derartige Hydrauliksteuerungen werden in der Praxis unter anderem in Absetzkippern verwendet, d.h. in Fahrzeugen mit mehreren Hydraulikverbrauchem, die einzeln oder auch teilweise überlappend zu steuern sind. Die Druckversorgung erfolgt bei einer solchen, aus der Praxis durch Vorbenutzung bekannten Hydrauliksteuerung mittels einer Mehrstufen-Konstantpumpe über einen einzigen Antrieb. Die Leistung des Antriebs ist begrenzt. Die Mehrstufen-Konstantpumpe ist eine Zweistufen- oder Doppel-Konstantpumpe, deren jede Pumpenstufe eine einzige Sektion der Verbrauchergruppe mit einer bestimmten Fördermenge versorgt, so dass ein Zweikreis-Druckversorgungssystem vorliegt. Jede Pumpenstufe fördert über einen Stromregler zum Tank, wenn kein Leistungsbedarf in der zugeordneten Verbrauchersektion vorliegt. Wird dabei in der anderen Verbrauchersektion ein Verbraucher gesteuert, ist nur die Fördermenge der dieser Sektion zugeordneten Pumpenstufe nutzbar, während die Fördermenge der anderen Pumpenstufe ungenutzt in den Tank abströmt. Für jede Pumpenstufe kann eine Lastdruckgrenze eingestellt sein, damit bei Betätigen von Verbrauchern in beiden Sektionen die Leistungsgrenze des Antriebs nicht überschritten wird.Such hydraulic controls are used in practice, inter alia, in skip loaders, i. in vehicles with several hydraulic loads, which can be controlled individually or partially overlapping. The pressure supply takes place in such known from practice by prior use hydraulic control by means of a multi-stage fixed displacement pump via a single drive. The power of the drive is limited. The multi-stage constant pump is a two-stage or double constant-action pump, each pump stage of which supplies a single section of the consumer group with a specific flow rate, so that there is a two-circuit pressure supply system. Each pump stage delivers to the tank via a flow regulator when there is no power requirement in the associated consumer section. If a consumer is controlled in the other consumer section, only the delivery rate of the pump stage assigned to this section can be utilized, while the delivery rate of the other pump stage flows unused into the tank. For each pump stage, a load pressure limit can be set so that when operating loads in both sections, the power limit of the drive is not exceeded.

Bei der US 4 559 965 A bekannten Ablass-Hydrauliksteuerung einer Erdbearbeitungsmaschine sind an ein Einkreis-Druckversorgungssystem zwei Konstantpumpen parallel angeschlossen. Zwischen einer Rücklaufleitung von den Ablasssteuerventilen der Hydrauliksteuerung und den beiden Pumpen sind zwei parallele Druckwaagen vorgesehen, deren jede durch ein Lastdrucksignal in Schließrichtung und ein Drucksignal aus der Einleitungsdruckversorgung in Aufsteuerrichtung vorgesteuert ist. Der Lastdruck Signal-Steuerkreis ist über zwei einstellbare Druckbegrenzungsventile zum Rücklauf abgesichert, wobei jedes Druckbegrenzungsventil durch das über eine Blende übertragene Lastdrucksignal geöffnet wird. Die beiden Druckbegrenzungsventile sind auf unterschiedliche Druckgrenzen eingestellt.In US 4 559 965 A known drain hydraulic control of an earthworking machine, two constant-displacement pumps are connected in parallel to a single-circuit pressure supply system. Between a return line from the drain control valves of the hydraulic control and the two pumps, two parallel pressure compensators are provided, each of which is pilot-operated by a load pressure signal in the closing direction and a pressure signal from the inlet pressure supply in the opening direction. The load pressure signal control circuit is protected by two adjustable pressure relief valves to the return, with each pressure relief valve through the through an aperture transmitted load pressure signal is opened. The two pressure relief valves are set to different pressure limits.

Bei der aus EP 0 190 431 A bekannten Hydrauliksteuerung für einen Gabelstapler erfolgt eine Förderstromanpassung mit Hilfe zweier Konstantpumpen, die ein Einleitungs-Druckversorgungssystem versorgen, wobei die Reihenfolge des Zuschaltens der Konstantpumpen allein abhängig ist von der Federvorspannung einer ihrer Konstantpumpe zugeordneten Druckwaage. Die Druckwaage mit der niedrigsten Federvorspannung schaltet die zugehörige Konstantpumpe zuletzt zum Arbeitskreis. Zur Druckbegrenzung der Hydrauliksteuerung ist ein einziges Druckbegrenzungsventil zwischen dem Lastdruck-Steuerkreis und der Rücklaufleitung vorgesehen, das bei Ansprechen beide Druckwaagen gleichzeitig in ihre Stellungen bringt, in denen die zugeordnete Konstantpumpe direkt in die Rücklaufleitung fördert.In the known from EP 0 190 431 A hydraulic control for a forklift is carried out a flow adjustment using two constant-displacement pumps that supply a single-line pressure supply system, the order of Zuschaltens the constant pump is solely dependent on the spring preload of one of their constant pump associated pressure compensator. The pressure balance with the lowest spring preload switches the associated constant pump last to the working group. To limit the pressure of the hydraulic control, a single pressure relief valve between the load pressure control circuit and the return line is provided which brings both pressure compensators simultaneously in response to their positions in response, in which promotes the associated constant pump directly into the return line.

Der Erfindung liegt die Aufgabe zugrunde, eine Hydrauliksteuerung der eingangs genannten Art zu schaffen, in der die Verbraucher eine aus den Pumpenstufen verfügbare, maximale Fördermenge größer als die Fördermenge nur einer Pumpenstufe unter Vermeidung von Druckschwingungen im System nutzen können.The invention has for its object to provide a hydraulic control of the type mentioned, in which the consumers can use a available from the pump stages, maximum flow greater than the flow rate of only one pump stage while avoiding pressure oscillations in the system.

Die gestellte Aufgabe wird mit den Merkmalen des Anspruchs 1 gelöst.The stated object is achieved with the features of claim 1.

Da die vorhandenen Pumpenstufen in das allen Verbrauchern gemeinsame Einkreis-Druckversorgungssystem fördern, steht zumindest bis zum Erreichen der niedrigeren Lastdruckgrenze die gesamte Fördermenge aus allen Pumpenstufen zur Nutzung durch jeden Verbraucher zur Verfügung. Da diese kombinierte Fördermenge nur bis zum Erreichen der niedrigeren Lastdruckgrenze tatsächlich zum Steuern eines oder mehrerer Verbraucher benutzt wird, wird auch der gemeinsame Antrieb der Mehrstufen-Konstantpumpe nicht über seine Leistungsgrenze belastet. Sobald jedoch die niedrigere Lastdruckgrenze erreicht und die zugehörige Pumpenstufe auf drucklosen Umlauf geschaltet wird, bleibt im Einkreis-Druckversorgungssystem weiterhin die Fördermenge der Pumpenstufe mit der höchsten Lastdruckgrenze nutzbar. Da dann die Leistungsabnahme der wenigstens einen Pumpenstufe mit niedrigerer Lastdruckgrenze verringert ist, kann zumindest die höchste Lastdruckgrenze der dann weiter zur Steuerung benutzten Pumpenstufe optimal hochgesetzt werden. Es lässt sich auf diese Weise beispielsweise mit mehreren Pumpenstufen eine treppenartige, für eine bezüglich der Leistungsgrenze des Antriebs optimale Förderleistung erzielen. Druckschwingungen im System werden vermieden, und zwar sowohl beim Umschalten des jeweiligen Ablass-Druckwaagenregelventils auf drucklosen Durchlauf als auch bei normalen Druckregelvorgängen vor Erreichen der Lastdruckgrenze, da im Steuerkreis zwischen dem Lastdruckmeldekreis und den Sicherheitsventilen eine hydraulische Dämpfvorrichtung vorgesehen ist. Die Dämpfvorrichtung weist eine Dämpfdrossel und zwei gegensinnige Beipass-Rückschlagventile auf, von denen nur eines, zweckmäßigerweise das in Strömungsrichtung zum Lastdruckmeldekreis öffnende Rückschlagventil, federbeaufschlagt wird.Since the existing pump stages promote the single-circuit pressure supply system common to all consumers, the entire delivery rate from all pump stages is available for use by every consumer at least until the lower load pressure limit is reached. Since this combined delivery is actually used only to reach the lower load pressure limit for controlling one or more consumers, and the common drive of the multi-stage constant pump is not charged beyond its capacity limit. However, as soon as the lower load pressure limit is reached and the associated pump stage is switched to pressureless circulation, the delivery rate of the pump stage with the highest load pressure limit remains available in the single-circuit pressure supply system. Since then the decrease in power of at least one pump stage is reduced with lower load pressure limit, at least the highest load pressure limit of the then continue to Control used pump stage are optimally elevated. It can be achieved in this way, for example, with several pump stages a staircase-like, for a respect to the power limit of the drive optimal flow rate. Pressure oscillations in the system are avoided, both when switching the respective discharge pressure compensator control valve on non-pressurized flow as well as normal pressure control operations before reaching the load pressure limit, since a hydraulic damping device is provided in the control circuit between the load pressure detection circuit and the safety valves. The damping device has a damping throttle and two opposite bypass check valves, of which only one, advantageously the opening in the flow direction to the load pressure detection circuit check valve is spring-loaded.

Bei einer zweckmäßigen Ausführungsform ist ein gemeinsamer Lastdruckmeldekreis für alle Lastdruckabgriffe der Verbrauchergruppe vorgesehen. Aus dem Lastdruckmeldekreis werden die Druckwaagen-Ablassventile gegen den Versorgungsdruck vorgesteuert, der aus dem Einkreis-Druckversorgungssystem abgegriffen wird. Damit dann, wenn eine Pumpenstufe mit niedrigerer Lastdruckgrenze im drucklosen Umlauf arbeitet, kein Druckmittel von der Pumpenstufe mit der höheren Lastdruckgrenze abströmen kann, ist die jeweils auf eine niedrigere Lastdruckgrenze eingestellte Pumpenstufe durch ein Rückschlagventil gegenüber dem Einkreis-Druckversorgungssystem abgesichert. Ferner ist nur dem Sicherheitsventil, an dem jeweils die niedrigere Lastdruckgrenze eingestellt wird, die Blende vorgesetzt, die verhindert, dass bei Ansprechen dieses Sicherheitsventils auch der Lastdruck für das jeweils andere Sicherheitsventil abgebaut wird. Mit dieser Verschaltung stellt sich die Hydrauliksteuerung selbsttätig auf die jeweiligen Operationsbedingungen ein, so dass zumindest bis zum Ansprechen eines Sicherheitsventils eine kombinierte maximale Fördermenge im Einkreis-Druckversorgungssystem von allen Verbrauchern der Verbrauchergruppe nutzbar ist.In an expedient embodiment, a common load pressure signaling circuit is provided for all load pressure taps of the consumer group. From the load pressure alarm circuit, the pressure compensator drain valves are precontrolled against the supply pressure, which is tapped from the single-circuit pressure supply system. So that when a pump stage with lower load pressure limit works in the non-pressurized circulation, no pressure medium from the pump stage with the higher load pressure limit can flow, each set to a lower load pressure limit pump stage is secured by a check valve against the single-circuit pressure supply system. Furthermore, only the safety valve, to which the lower load pressure limit is set in each case, the diaphragm is preset, which prevents the response of this safety valve and the load pressure for the other safety valve is reduced. With this interconnection, the hydraulic control adjusts automatically to the respective operating conditions, so that at least until the response of a safety valve, a combined maximum flow in the single-circuit pressure supply system of all consumers of the consumer group is available.

Da der Leistungsbedarf einer Pumpenstufe dann deutlich verringert ist, wenn das zugeordnete Sicherheitsventil angesprochen hat und das Druckwaagen-Ablassregelventil auf drucklosen Umlauf schaltet, lässt sich dann die Leistung des Antriebs überwiegend zur Förderung mit der Pumpenstufe nutzen, die auf die höchste Lastdruckgrenze eingestellt ist. Diese Pumpenstufe wird zweckmäßig auch mit der höchsten Fördermenge ausgelegt. Die Fördermengen weiterer Pumpenstufen werden stufenweise abnehmend eingestellt, wobei die jeweils eingestellten Lastdruckgrenzen ebenfalls mit den abnehmenden Fördermengen gestuft abnehmen können. Auf diese Weise lässt sich das bereits erwähnte Treppenprofil der Druck/Fördermengen-Charakteristik optimal einstellen.Since the power requirement of a pump stage is then significantly reduced when the associated safety valve has responded and the pressure compensator relief control valve switches to non-pressurized circulation, then the power of the drive can be used predominantly for pumping at the pump level which is at the highest load pressure limit is set. This pump stage is expediently designed with the highest flow rate. The delivery rates of other pump stages are set in stages decreasing, whereby the respective set load pressure limits can also decrease stepwise with the decreasing flow rates. In this way, the already mentioned stair profile of the pressure / flow characteristics can be optimally adjusted.

Bei einer zweckmäßigen Ausführungsform wird nur eine Zweistufen- oder Doppelkonstantpumpe vorgesehen, deren Pumpenstufen-Fördermengen in einem Verhältnis von etwa 2:1 stehen. Die Lastdruckgrenze für die Pumpenstufe mit der höchsten Fördermenge wird um etwa 50 % höher eingestellt, als die Lastdruckgrenze der anderen Pumpenstufe. Beispielsweise wird bei einer Fördermenge der einen Pumpenstufe von etwa 77 l/min die Lastdruckgrenze auf etwa 300 Bar eingestellt, während bei der Pumpenstufe mit einer Fördermenge von etwa 38,5 l/min die Lastdruckgrenze auf nur etwa 200 Bar eingestellt wird.In an expedient embodiment, only a two-stage or double-constant pump is provided whose pump stage flow rates are in a ratio of about 2: 1. The load pressure limit for the pump stage with the highest flow rate is set approximately 50% higher than the load pressure limit of the other pump stage. For example, with a flow rate of a pump stage of about 77 l / min, the load pressure limit is set to about 300 bar, while in the pump stage with a flow rate of about 38.5 l / min, the load pressure limit is set to only about 200 bar.

Schließlich ist es zweckmäßig, einzelne Lastdruckleitungsabschnitte stromauf der hydraulischen Dämpfvorrichtung über Wechselventile miteinander zu verknüpfen, so dass den Sicherheitsventilen stets der höchste Lastdruck von den betätigten Verbrauchern gemeldet wird.Finally, it is expedient to link individual load-pressure line sections upstream of the hydraulic damping device with one another via shuttle valves, so that the safety valves are always informed of the highest load pressure from the actuated consumers.

Anhand der Zeichnung wird eine Ausführungsform des Erfindungsgegenstandes erläutert. Fig. 1 ist ein Blockschaltbild einer Hydrauliksteuerung, wie sie beispielsweise bei einem Absetzkipper für dessen hydraulische Verbraucher nutzbar ist.Reference to the drawings, an embodiment of the subject invention will be explained. Fig. 1 is a block diagram of a hydraulic control, as used for example in a skip loader for the hydraulic consumer.

Eine in Fig. 1 gezeigte Hydrauliksteuerung S dient zum Betätigen mehrerer Verbraucher einer Verbrauchergruppe, von der der Einfachheit halber nur zwei Verbraucher V1 und V2 angedeutet sind, obwohl durchaus weitere, in Fig. 1 nicht gezeigte Verbraucher vorgesehen und in die Hydrauliksteuerung S eingegliedert sein können.A hydraulic control S shown in FIG. 1 is used to actuate a plurality of consumers of a consumer group, for the sake of simplicity, only two consumers V1 and V2 are indicated, although certainly further, not shown in Fig. 1 consumer provided and incorporated into the hydraulic control S. ,

In der Hydrauliksteuerung S wird jeder Verbraucher V1, V2 mittels eines Wegesteuerventils C1, C2 in seiner Richtung und Geschwindigkeit gesteuert. Die Wegeventile C1, C2 sind beispielsweise magnet- und handbetätigte Proportionalwegesteuerventile mit Druckvorsteuerung und jeweils mindestens einem Lastdruckabgriff L für den Lastdruck des Verbrauchers V1, V2. Die Wegesteuerventile C1, C2 sind an ein gemeinsames Einkreis-Druck-versorgungssystem 3, 4, 5 sowie über eine Tankleitung 6 an einen Tank T angeschlossen. Zur Druckversorgung ist eine Mehrstufen-Konstantpumpe P vorgesehen, die von einem einzigen Antrieb A angetrieben wird. Im gezeigten Ausführungsbeispiel in Fig. 1 handelt es sich um eine Zweistufen- oder Doppel-Konstantpumpe mit einer ersten Pumpenstufe P1 für eine Fördermenge Q1 und einer zweiten Pumpenstufe P2 für eine Fördermenge Q2. Die Fördermenge Q1 beträgt beispielsweise etwa 38,5 l/min, während die Fördermenge Q2 beispielsweise 77 l/min beträgt.In the hydraulic control S, each consumer V1, V2 is controlled by means of a directional control valve C1, C2 in its direction and speed. The directional control valves C1, C2 are, for example, magnetically and manually operated proportional directional control valves Pressure pre-control and in each case at least one load pressure tap L for the load pressure of the consumer V1, V2. The directional control valves C1, C2 are connected to a common single-circuit pressure supply system 3, 4, 5 and via a tank line 6 to a tank T. For pressure supply a multi-stage fixed displacement pump P is provided, which is driven by a single drive A. 1 is a two-stage or double constant-flow pump with a first pump stage P1 for a delivery rate Q1 and a second pump stage P2 for a delivery rate Q2. The flow rate Q1 is, for example, about 38.5 l / min, while the flow rate Q2 is 77 l / min, for example.

Von den Pumpenstufen P1, P2 führen Anschlussleitungen 1, 2 zu einer Zusammenführung 3, von der eine Versorgungsleitung 4 zu einer allen Verbrauchern V1, V2 gemeinsamen Hauptversorgungsleitung 5 führt.From the pump stages P1, P2 lead connecting lines 1, 2 to a merge 3, of which a supply line 4 leads to a common to all consumers V1, V2 main supply line 5.

Ferner ist ein gemeinsamer Lastdruckmeldekreis 8 vorgesehen, an den die Lastdruckgriffe L aller Wegesteuerventile C1, C2 angeschlossen sind, zweckmäßigerweise über einzelne Lastdrucksteuerleitungsabschnitte verknüpfende Wechselventile W.Furthermore, a common load pressure signaling circuit 8 is provided, to which the load pressure handles L of all directional control valves C1, C2 are connected, expediently via individual load pressure control line sections linking shuttle valves W.

Jeder Pumpenstufe P1, P2 ist ein Druckwaagen-Ablassregelventil DW1, DW2 zum Tank T zugeordnet, das durch eine Regelfeder F1, F2 in Schlließrichtung beaufschlagt ist. Ferner sind die Schließsteuerseiten der Druckwaagen-Ablassregelventile DW1, DW2 an den gemeinsamen Lastdruckmeldekreis 8 angeschlossen. Zu diesem Zweck zweigt von einem zentralen Wechselventil W eine Steuerleitung 9 ab, in der eine hydraulische Dämpfungsvorrichtung 10 angeordnet ist, und die zu einer Abzweigung 11 führt.Each pump stage P1, P2 is associated with a pressure compensator Ablaßregelventil DW1, DW2 to the tank T, which is acted upon by a control spring F1, F2 in Schlließrichtung. Further, the closing control sides of the pressure compensator discharge control valves DW1, DW2 are connected to the common load pressure detecting circuit 8. For this purpose, branches off from a central shuttle valve W from a control line 9, in which a hydraulic damping device 10 is arranged, and leading to a branch 11.

Die hydraulische Dämpfungsvorrichtung 10 enthält eine Dämpfdrossel 20 und zwei gegensinnig angeordnete Beipass-Rückschlagventile 21, 22, von denen zumindest das zum Lastdruckmeldekreis 8 öffnende Beipass-Rückschlagventil 22 federbeaufschlagt (Ventilfeder 23) sein kann.The hydraulic damping device 10 includes a damping throttle 20 and two counter-bypass check valves 21, 22 arranged in opposite directions, of which at least the bypass check valve 22 which opens to the load pressure signaling circuit 8 can be spring-loaded (valve spring 23).

Von der Abzweigung 11 führt eine Steuerleitung 12 zur Schließsteuerseite des Druckwaagen-Ablassregelventils DW1 und zum Eingang eines Sicherheitsventils 13, das durch eine Feder in Schließrichtung beaufschlagt und in Öffnungsrichtung aus der Steuerleitung 12 druckvorgesteuert ist. Stromauf des Sicherheitsventils 13 und stromab der Abzweigung 11 ist eine Blende B vorgesehen. Das Sicherheitsventil 13 ist auf eine niedrige Lastdruckgrenze eingestellt, beispielsweise auf 200 Bar.From the branch 11, a control line 12 leads to the closing control side of the pressure compensator Ablassregelventils DW1 and the input of a safety valve 13 which is acted upon by a spring in the closing direction and pressure controlled in the opening direction from the control line 12. Upstream of the safety valve 13 and downstream of the branch 11, a diaphragm B is provided. The safety valve 13 is set to a low load pressure limit, for example to 200 bar.

Von der Abzweigung 11 führt eine Steuerleitung 14 zu einem weiteren Sicherheitsventil 15, das funktionell dem Sicherheitsventil 13 entspricht, und auch zur Schließsteuerseite des anderen Druckwaagen-Ablassregelventils DW2. Das Sicherheitsventil 15 ist auf eine höhere Lastdruckgrenze bzw. auf die höchste Lastdruckgrenze eingestellt, beispielsweise auf etwa 300 Bar. Die erwähnten Lastdruckgrenzen können beispielsweise anhand der Sicherheitsventilfedern variiert werden. In der Steuerleitung 14 ist keine Blende enthalten.From the branch 11, a control line 14 leads to a further safety valve 15, which functionally corresponds to the safety valve 13, and also to the closing control side of the other pressure compensator drain control valve DW2. The safety valve 15 is set to a higher load pressure limit or to the highest load pressure limit, for example to about 300 bar. The mentioned load pressure limits can be varied, for example, based on the safety valve springs. In the control line 14, no aperture is included.

Die Aufsteuerseiten der beiden Druckwaagen-Ablassregelventile DW1, DW2 sind an das Einkreis-Druckversorgungssystem 3, 4, 5 angeschlossen. Im Detail zweigt zur Aufsteuerdruckseite des Druckwaagen-Ablassregelventils DW1 eine Steuerleitung 16 von der Zusammenführung 3 ab. In der Steuerleitung 16 ist eine Blende 17 enthalten. Die Steuerleitung 16 könnte auch zur Aufsteuerseite des anderen Druckwaagen-Ablassregelventils DW2 geführt sein. Bei der gezeigten Ausführungsform zweigt jedoch eine Steuerleitung 18 in etwa in Verlängerung der Anschlussleitung 2 zur Aufsteuerseite des Druckwaagen-Ablassregelventils DW2 ab. In der Steuerleitung 18 ist ebenfalls eine Blende 19 enthalten.The control sides of the two pressure compensator drainage control valves DW1, DW2 are connected to the single-circuit pressure supply system 3, 4, 5. In detail, a control line 16 branches off from the merge 3 to the pilot pressure side of the pressure compensator drain control valve DW1. In the control line 16, a diaphragm 17 is included. The control line 16 could also be led to the control side of the other pressure compensator Ablassregelventil DW2. In the embodiment shown, however, a control line 18 branches off approximately in extension of the connection line 2 to the control side of the pressure compensator drain control valve DW2. In the control line 18, a diaphragm 19 is also included.

Weitere schaltungstechnische Details in Fig. 1 sind für die Erfindung von nebensächlicher Bedeutung und werden deshalb nicht detailliert erläutert.Further circuit details in Fig. 1 are of secondary importance to the invention and are therefore not explained in detail.

Funktion:Function:

Wird der Antrieb A eingeschaltet, dann fördern beide Pumpenstufen P1, P2 ihre Fördermengen Q1, Q2. Die Druckwaagen-Ablassregelventile DW1, DW2 sind in ihren Schließstellungen. Wird kein Verbraucher V1, V2 betätigt, dann stellen die Steuerdrücke in den Steuerleitungen 16 und 18 die beiden Druckwaagen-Ablassregelnventile in die Durchgangsstellungen, so dass die Fördermengen Q1, Q2 im drucklosen Durchlauf in den Tank T zurückströmen.If the drive A is turned on, then promote both pump stages P1, P2 their flow rates Q1, Q2. The pressure compensator drain control valves DW1, DW2 are in their closed positions. If no consumer V1, V2 is actuated, then set the control pressures in the control lines 16 and 18, the two pressure compensator Ablassregelventile in the passage positions, so that the flow rates Q1, Q2 flow back into the tank T in the non-pressurized passage.

Wird beispielsweise der Verbraucher V1 durch Betätigen des Wegesteuerventils C1 gesteuert, so baut sich im Lastdruckmeldesystem 8 ein Lastdruck entsprechend der vorhandenen Last auf. Dieser Lastdruck verstellt die beiden Druckwaagen-Ablassregelventile DW1, DW2 in Schließrichtung, derart, dass der Versorgungsdruck im Einkreis-Druckversorgungssystem 3, 4, 5 jeweils geringfügig höher ist als der erforderliche Lastdruck. Bis zum Erreichen der niedrigeren Lastdruckgrenze des Sicherheitsventils 13 sind im Einkreis-Druckversorgungssystem 3, 4, 5 die kombinierten Fördermengen Q1, Q2 von jedem Verbraucher V1, V2 nutzbar. Über die Wechselventile W wird der jeweils höchste Lastdruck gemeldet, so dass der Versorgungsdruck entsprechend ansteigt.If, for example, the consumer V1 is controlled by actuating the directional control valve C1, a load pressure corresponding to the existing load builds up in the load pressure reporting system 8. This load pressure adjusts the two pressure compensator Ablassregelventile DW1, DW2 in the closing direction, such that the supply pressure in the single-circuit pressure supply system 3, 4, 5 each slightly higher than the required load pressure. Until the lower load pressure limit of the safety valve 13 is reached, the combined delivery quantities Q1, Q2 of each consumer V1, V2 can be used in the single-circuit pressure supply system 3, 4, 5. About the shuttle valves W the highest load pressure is reported, so that the supply pressure increases accordingly.

Wird im Lastdruckmeldesystem 8 die niedrigere Lastdruckgrenze des Sicherheitsventils 13 erreicht, dann wird das Sicherheitsventil 13 auf Durchgang geschaltet und die Steuerleitung 12 entlastet. Das Druckwaagen-Ablassregelventil DW1 wird über den Druck in der Steuerleitung 16 auf Durchgang gestellt, so dass die Fördermenge Q1 in den Tank T abströmt. Da das Sicherheitsventil 15 bei dieser niedrigeren Lastdruckgrenze nicht anspricht, wird das Einkreis-Druckversorgungssystem 3, 4, 5 weiterhin mit der Fördermenge Q2 der anderen Pumpenstufe P2 gespeist.If the lower load pressure limit of the safety valve 13 is reached in the load pressure reporting system 8, then the safety valve 13 is switched to passage and the control line 12 is relieved. The pressure compensator Ablaßregelventil DW1 is made to pass through the pressure in the control line 16, so that the flow rate Q1 flows into the tank T. Since the safety valve 15 does not respond at this lower load pressure limit, the single-circuit pressure supply system 3, 4, 5 continues to be supplied with the delivery rate Q2 of the other pump stage P2.

Damit bei drucklosem Umlauf der Pumpenstufe P1 kein Druckmittel von der Zusammenführung 3 über das offene Druckwaagen-Ablassregelventil DW1 abströmt, ist zwischen der Anschlussleitung 1 und der Zusammenführung 3 ein Rückschlagventil 7 vorgesehen, das in Strömungsrichtung zum Druckwaagen-Ablassregelventil DW1 sperrt.So that no pressure medium flows from the combination 3 via the open pressure compensator-drain control valve DW1 in the unpressurized circulation of the pump stage P1, a check valve 7 is provided between the connecting line 1 and the junction 3, which blocks in the flow direction to the pressure compensator drain control valve DW1.

Jeder Verbraucher V1, V2 kann dann bis zum Erreichen der höchsten Lastdruckgrenze des Sicherheitsventils 15 weiterhin mit der Fördermenge Q2 betrieben werden, wobei, zweckmäßigerweise, die Fördermenge Q2 und die höchste Lastdruckgrenze am Sicherheitsventil 15 so gewählt sind, dass bei Erreichen der höchsten Lastdruckgrenze der Antrieb A gerade nicht überbelastet wird.Each consumer V1, V2 can then continue to operate until reaching the highest load pressure limit of the safety valve 15 with the flow rate Q2, which, suitably, the flow rate Q2 and the highest load pressure limit are selected at the safety valve 15 so that upon reaching the highest load pressure limit of the drive A is not overloaded.

Obwohl in Fig. 1 nur eine Zweistufen- oder Doppel-Konstantpumpe P gezeigt ist, könnte die Hydrauliksteuerung eine Mehrstufen-Konstantpumpe P mit mehr als zwei Pumpenstufen umfassen. Dann müsste jeweils eine Pumpenstufe mit niedriger Lastdruckgrenze durch ein Rückschlagventil entsprechend dem Rückschlagventil 7 gegenüber einer Pumpenstufe mit höherer Lastdruckgrenze abgesichert sein. Ferner müsste jedes Sicherheitsventil, das auf eine niedrigere als die höchste Lastdruckgrenze eingestellt ist, durch eine Blende analog zur Blende B abgesichert sein, um zu verhindern, dass der bei Ansprechen des zugeordneten Druckwaagen-Ablassregelventils entlastete Steuerdruck auch den Steuerdruck für das auf eine höhere Lastdruckgrenze eingestellte Sicherheitsventil verringern könnte.Although only a two-stage or dual constant-displacement pump P is shown in FIG. 1, the hydraulic controller could include a multi-stage fixed displacement pump P having more than two pump stages. Then, in each case one pump stage with a low load pressure limit would have to be secured by a check valve corresponding to the check valve 7 with respect to a pump stage with a higher load pressure limit. Furthermore, each safety valve, which is set to a lower than the highest load pressure limit, would have to be secured by a diaphragm analogous to the diaphragm B, to prevent the relieved in response of the associated pressure compensator Ablaßregelventils control pressure and the control pressure for the to a higher load pressure limit set safety valve could decrease.

Die Größe der Blende B ist so gewählt, dass die Blende B weniger Steuerdruckmittel abströmen lässt, als Steuerdruckmittel aus dem Lastdruckmeldesystem 8 nachströmt.The size of the diaphragm B is selected so that the diaphragm B allows less control pressure fluid to flow out, as the control pressure fluid flows from the load pressure reporting system 8.

Die hydraulische Dämpfungsvorrichtung 10 ist wichtig, da die Dämpfungsdrossel 20, obwohl sie in beiden Strömungsrichtungen über das jeweilige Rückschlagventil 21 oder 22 umgehbar ist, Druckschwingungen im Steuerkreis rasch zum Abklingen bringt, ehe diese über die Druckwaagen DW1, DW2 in die Arbeitsleitungen übertragen werden, und/oder falls solche Druckschwingungen aus den Arbeitsleitungen oder von den Verbrauchern her in den Steuerkreis übertragen worden sind.The hydraulic damping device 10 is important because the damping throttle 20, although it is bypassable in both directions of flow through the respective check valve 21 or 22, quickly brings pressure oscillations in the control circuit to decay before they are transmitted via the pressure compensators DW1, DW2 in the working lines, and / or if such pressure oscillations have been transferred from the working lines or from the consumers into the control circuit.

Anstelle der Druckwaagen-Ablassregelventile DW1, DW2 könnten auch Dreiwege-Stromregelventile benutzt werden. Ferner ist es möglich, die Sicherheitsventile 13, 15 anders auszubilden als durch die Symbole angedeutet.Instead of the pressure compensator drain control valves DW1, DW2, three-way flow control valves could also be used. Furthermore, it is possible to design the safety valves 13, 15 differently than indicated by the symbols.

Claims (5)

  1. Hydraulic control system (S) for a consuming unit assembly (V1, V2) controllable via directional control valves (C1, C2) with load pressure pick-up (L), especially for a plurality of consuming units of a skip loader, comprising a multistage fixed displacement pump (P) which is driven by a common drive (A) and respectively one pump stage (P1, P2) of which, delivering an individual output (Q1, Q2), is connected to the pressure supply at least of a section of the consuming unit assembly, comprising a pressure-balance relief control valve (DW1, DW2), which is assigned to each pump stage (P1, P2) and is controlled as a function of load pressure and pump pressure, and comprising safety valves (13, 15), assigned to the pressure-balance relief valves (DW1, DW2) of the pump stages (P1, P2), for limiting the load pressure in a load-pressure indicator circuit (8), wherein the safety valves (13, 15) are set to different load pressure limits and all pump stages (P1, P2) are connected to a single-circuit pressure supply system (3, 4, 5) which is common to all consuming units (V1, V2) and in which with rising load pressure, until such time as a respectively lower load pressure limit is reached on a load-dependent basis, a combined output consisting of the output (Q2) of the pump stage (P2) having the highest load pressure limit and at least the output (Q1) of the pump stage (P1) having the next lower load pressure limit for each consuming unit (V1, V2) is utilizable, characterized in that between the load pressure indicator circuit (8) and the safety valves (13, 15) a hydraulic damping device (10) is provided, which comprises a damping throttle (20) and two oppositely working bypass check valves (21, 22), only one of which is spring-loaded.
  2. Hydraulic control system according to Claim 1, characterized in that a common load pressure indicator circuit (8), connected to the pressure-balance relief control valves (DW1, DW2) on their closing sides, is provided for all load pressure pick-ups (L), in that the single-circuit pressure supply system (3, 4, 5) is connected to the opening sides of the pressure-balance relief control valves (DW1, DW2), in that between a convergence (3) of the pump stages (P1, P2) into the single-circuit pressure supply system and a connecting line (1) from the pump stage (P1) to which the lower load pressure limit is assigned, and the pressure-balance relief control valve (DW1), there is disposed a check valve (7) which shuts off the path to the pressure-balance relief control valve (DW1), and in that, downstream of the hydraulic damping device (10) and of a branch connection (11) from the load pressure indicator circuit (8) to the safety valves (13, 15), an orifice plate (B) is placed only in front of the safety valve (13) at which the lower load pressure limit is respectively set.
  3. Hydraulic control system according to Claim 1, characterized in that the safety valve (15) of the pump stage (P2) having the highest output (Q2) is set to the highest load pressure limit, and in that safety valves (13) of further pump stages (P1, P2), which deliver outputs (Q1) that decrease in steps relative to the highest output (Q2), are set to load pressure limits which decrease step by step as the outputs (Q1) decrease.
  4. Hydraulic control system according to Claim 1, characterized in that the multistage fixed displacement pump (P1) is a two-stage or double fixed displacement pump, the pump stage outputs (Q2, Q1) of which are in a ratio of about 2:1, the load pressure limit of the safety valve (15) of the pump stage (P2) having the highest output (Q2) being set about 50% higher than the load pressure limit of the safety valve (13) of the other pump stage (P1), preferably, in the case of outputs of 77 and 38.5 l/min, to 300 and 200 bar respectively.
  5. Hydraulic control system according to Claim 2, characterized in that, in the load pressure indicator circuit (8) upstream of the hydraulic damping device (10), individual load pressure line sections are connected one to another via shuttle valves (W) indicating the respectively highest load pressure to the safety valves (13, 15).
EP20040011284 2003-09-09 2004-05-12 Hydraulic control Expired - Fee Related EP1515049B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE20313998U DE20313998U1 (en) 2003-09-09 2003-09-09 hydraulic control
DE20313998U 2003-09-09

Publications (2)

Publication Number Publication Date
EP1515049A1 EP1515049A1 (en) 2005-03-16
EP1515049B1 true EP1515049B1 (en) 2007-01-24

Family

ID=34072161

Family Applications (1)

Application Number Title Priority Date Filing Date
EP20040011284 Expired - Fee Related EP1515049B1 (en) 2003-09-09 2004-05-12 Hydraulic control

Country Status (2)

Country Link
EP (1) EP1515049B1 (en)
DE (2) DE20313998U1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20220013300A (en) * 2020-07-24 2022-02-04 에이치에이더블유이 하이드롤릭 에스이 Preselection valve, hydraulic valve assembly and hydraulic control unit

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US190431A (en) 1877-05-08 Improvement in gas-burners
US4559965A (en) 1984-01-09 1985-12-24 J. I. Case Company Multiple compensating unloading valve circuit
DE3503559A1 (en) * 1985-02-02 1986-08-07 Robert Bosch Gmbh, 7000 Stuttgart HYDRAULIC SYSTEM

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20220013300A (en) * 2020-07-24 2022-02-04 에이치에이더블유이 하이드롤릭 에스이 Preselection valve, hydraulic valve assembly and hydraulic control unit
KR102436724B1 (en) 2020-07-24 2022-08-25 에이치에이더블유이 하이드롤릭 에스이 Preselection valve, hydraulic valve assembly and hydraulic control unit

Also Published As

Publication number Publication date
DE502004002747D1 (en) 2007-03-15
EP1515049A1 (en) 2005-03-16
DE20313998U1 (en) 2005-01-13

Similar Documents

Publication Publication Date Title
EP1915538B1 (en) Circuit for controlling a double-action hydraulic drive cylinder
EP1092095B2 (en) Hydraulic circuit
DE102006003414B3 (en) Hydraulic circuit arrangement
EP0958455B1 (en) Hydraulic control circuit for a priority and for a secondary hydraulic consumer
DE102012207422A1 (en) Hydraulic control system used for working machine e.g. mini excavators, has pressure reduction device for high load pressure, which is more adjusted in dependence of controlled volumetric flow of adjuster of the hydraulic pump
DE10219717B3 (en) Hydraulic valve arrangement
DE19615593A1 (en) Control for hydraulic drive
DE102014226182A1 (en) Control valve assembly and hydraulic drive system with it
DE102004048684A1 (en) Hydraulic control arrangement
DE4027047A1 (en) VALVE ARRANGEMENT FOR LOAD-INDEPENDENT CONTROL OF SEVERAL HYDRAULIC CONSUMERS
EP0190431B1 (en) Hydraulic system
DE102010048893A1 (en) Load-sensing controlled hydrostatic drive system
EP2404493B1 (en) Hoisting gear
DE19646427B4 (en) valve assembly
DE112004002768B4 (en) Hydraulic control system
EP1515049B1 (en) Hydraulic control
EP3135924B1 (en) Hydraulic device
DE19709958B4 (en) Hydrostatic drive system
DE4210252C1 (en)
EP0823559B1 (en) Hydraulic control device
WO2003087585A1 (en) Hydraulic control system using load-sensing technology
EP1954949B1 (en) Hydraulic control device
EP3398418A1 (en) Hydraulic system of a machine usable in agriculture or civil engineering
DE2800814A1 (en) Load compensated hydraulic control system - has pump adjusting mechanism connected to pilot valve discharging to tank
DE3844399C2 (en) Control arrangement for several independently operable hydraulic consumers and their use

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL HR LT LV MK

17P Request for examination filed

Effective date: 20050415

AKX Designation fees paid

Designated state(s): DE IT

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE IT

REF Corresponds to:

Ref document number: 502004002747

Country of ref document: DE

Date of ref document: 20070315

Kind code of ref document: P

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20071025

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: IT

Payment date: 20080521

Year of fee payment: 5

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20090512

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20140527

Year of fee payment: 11

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 502004002747

Country of ref document: DE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20151201