EP1302663B1 - Electro-hydraulic motor pump unit and check valve unit - Google Patents

Electro-hydraulic motor pump unit and check valve unit Download PDF

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Publication number
EP1302663B1
EP1302663B1 EP02010499A EP02010499A EP1302663B1 EP 1302663 B1 EP1302663 B1 EP 1302663B1 EP 02010499 A EP02010499 A EP 02010499A EP 02010499 A EP02010499 A EP 02010499A EP 1302663 B1 EP1302663 B1 EP 1302663B1
Authority
EP
European Patent Office
Prior art keywords
valve
pressure
cone
motor pump
aggregate
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
EP02010499A
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German (de)
French (fr)
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EP1302663A1 (en
Inventor
Martin Dipl.-Ing. Heusser
Gerhard Lörner
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
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Hawe Hydraulik GmbH and Co KG
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Publication of EP1302663A1 publication Critical patent/EP1302663A1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/028—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the actuating force
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B17/00—Pumps characterised by combination with, or adaptation to, specific driving engines or motors
    • F04B17/03—Pumps characterised by combination with, or adaptation to, specific driving engines or motors driven by electric motors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B23/00—Pumping installations or systems
    • F04B23/02—Pumping installations or systems having reservoirs
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/10—Other safety measures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
    • F04B53/04—Draining
    • 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
    • F15B20/00—Safety arrangements for fluid actuator systems; Applications of safety devices in fluid actuator systems; Emergency measures for fluid actuator systems
    • 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
    • F15B2211/20507—Type of prime mover
    • F15B2211/20515—Electric motor
    • 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
    • F15B2211/20592—Combinations of pumps for supplying high and low 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
    • F15B2211/30—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
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3105—Neutral or centre positions
    • F15B2211/3116—Neutral or centre positions the pump port being open in the centre position, e.g. so-called open centre
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—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
    • F15B2211/50—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
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5151—Pressure control characterised by the connections of the pressure control means in the circuit being connected to a pressure source and a directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5159—Pressure control characterised by the connections of the pressure control means in the circuit being connected to an output member 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
    • F15B2211/50—Pressure control
    • F15B2211/55—Pressure control for limiting a pressure up to a maximum pressure, e.g. by using a pressure relief 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
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7051—Linear output members
    • F15B2211/7053—Double-acting output members

Definitions

  • the invention relates to an electrohydraulic motor pump assembly according to the preamble of claim 1.
  • Electrohydraulic motor pump units according to DE 200 07 554 U are used on machine tools to control hydromechanical chuck or tool holding devices. Furthermore, electro-hydraulic motor pump units are used as transportable supply units for cutting or riveting tools, tools or screwdrivers.
  • the motor pump unit is equipped with an attachment that has the at least one consumer port to which the respective consumer, for example via hydraulic hoses or piping, is connected. Because of the high tightness of the valve components and also the manufacturing precision of the connectable hydraulic consumers even after switching off the motor pump unit still a considerable system pressure for a long time upright.
  • the pressure holding capacity is an undesirable disadvantage of the high quality of the cooperating hydraulic components under certain circumstances.
  • the maintained pressure especially makes it difficult for an AC motor to start up after a service interruption.
  • hose or pipe couplings can be solved only with relatively much effort, and can not reset the connected hydraulic consumers, for example, by hand, although this would be desirable for certain reasons.
  • a major reason for this long-term pressure holding capacity is the extensive freedom from leakage of the individual valve components in their closed positions, and in particular the complete absence of leakage of the pressure relief valves in the seat valve design.
  • this freedom from leakage for maximum pressures up to about 800 bar is a must to achieve the necessary working pressures reliably and quickly even with an AC motor and small flow rate of the high-pressure pump stage.
  • an externally driven variable displacement pump is provided, which is designed as a swash plate pump with axial piston.
  • a fluid-operated displacement control mechanism is incorporated, which adjusts the inclination of the swash plate according to the desired flow rate.
  • To the control pump directly and in parallel several directional control valves are connected. Only in the neutral position of all directional valves, the pressure side of the control pump via central channels of the directional control valves is connected to the return. The displacement control mechanism is shut off from the return. Thanks to the flow channels in the directional control valves, system pressure no longer prevails when the control pump has stopped and all directional control valves are in the neutral position.
  • a control pump is provided, which is connected on the delivery side via a supply line to a directional control valve with two sections.
  • a limit seat valve is provided with a permanently open to the return bypass to reduce the pilot pressure for a pressure in the supply line regulating valve in a pilot pressure circuit to the return at non-actuated hydraulic cylinders, so that the control pump to minimum flow rate becomes.
  • the control pump is constantly driven, but does not deliver at minimum flow rate.
  • the invention has for its object to provide a hydraulic motor pump unit of the type mentioned, in which the long-term pressure holding capacity of the hydraulic valve components is eliminated in a structurally simple manner and in the startup problems, for example, an AC motor can be avoided.
  • the pressure relief device in the attachment automatically reduces the pressure as soon as the electric motor stops. This considerably facilitates the restart of the electric motor.
  • this effect is advantageous because an AC motor otherwise needs a relatively high starting current, if necessary could overload the fuses of the normal network.
  • AC motors are used especially in portable motor pump units, so that the motor pump unit can be connected to the normal network just in mobile use.
  • light starting may be desirable.
  • the permanently open passport means only a negligible loss. For this additional function, no separate valve component is used, but an already necessary pressure relief valve.
  • the pressure limiting valve generates a predetermined leakage in its degree of leakage-free shut-off position, which, however, does not impair the pressure-limiting function.
  • the two pressure relief valves are set to different response pressures.
  • the bypass is expediently arranged in the pressure limiting valve with the lower response pressure, so that no losses are to be accepted in order to achieve the higher working pressure. In the case of a reset or release stroke of a hydraulic consumer controlled by the motor pump unit, the loss due to the by-pass does not matter.
  • An AC motor as an electric motor offers the advantage of being able to be connected to the normal AC mains.
  • the two-circuit pump stage makes it possible to first reach a lower pressure level with the relatively high displacement low-pressure pump stage, and then to come to very high working pressures with the low-pressure high-pressure pump stage, e.g. up to about 800.0,1 MPa (about 800 bar).
  • the directions of movement of the hydraulic consumer are controlled by means of the directional control valve, each pressure relief valve monitoring the maximum working pressure in a direction of movement.
  • the bypass is arranged in the pressure limiting valve monitoring the less important function or the lower pressure.
  • the by-pass is formed in a conical seat valve by a flattening in the conical surface of the valve cone.
  • the flattening forms in the shut-off position of the pressure relief valve with the valve seat a passage or a throttle one predetermined size over which the leakage flows.
  • the flattening is formed by a sanded surface whose production is simple.
  • the flattening should be parallel to the cone-generating, so that it can be precisely formed during grinding of the cone shroud by interrupting the rotational movement of the poppet only by advancing the grinding tool during grinding.
  • the by-pass could be formed by at least one notch in the valve seat.
  • the bypass is expediently designed to have a leakage of about 0.3 to 0.4.60.10 -3 m 3 / s (about 0.3 to 0.4 liters per minute) at 150.0.1 MPa (150 bar). This can be at least as far as possible pressure relief, for example, within a few seconds, z. B. about 5 seconds, bring about.
  • the by-pass could be formed by at least one notch in the valve seat.
  • the bypass is sized so that it produces a leakage of about 0.3 to 0.4 liters per minute at 150 bar.
  • at least a great deal of pressure relief can be achieved, for example, within a few seconds, e.g. about 5 seconds, bring about.
  • valve cone with a damping piston to avoid a nervous response of the pressure relief valve.
  • the damping effect is enhanced when the cavity of the damping piston is open to the outside via at least one channel and contains a check valve.
  • An electrohydraulic motor pump unit G ( Fig. 1 ) is installed as a supply unit, for example, a hydromechanical tool either stationary or used as a transportable unit.
  • a housing 1 which can form an oil reservoir T at the same time, an electric motor M with a fan 2 is provided as a drive of at least one pump stage P inside.
  • the electric motor M can be a three-phase motor, a DC motor or, in particular for mobile applications, an AC motor that can be supplied from the normal network.
  • An attachment C is attached to the housing 1 or integrated into this and communicates with at least one, not shown, pressure side port of the pump stage P in conjunction, and also with the leading into the housing 1 return.
  • the add-on element C points in Fig. 1 a block-like housing 7, on which a directional control valve 3 is mounted with a solenoid 4.
  • On attachment C one or two or more consumer terminals A, B and 5, 6 are provided.
  • the consumer port B or 6 is, preferably in the add-on element C, a hydraulic, automatic pressure relief device D assigned via the switched off electric motor M, the system pressure, at least in the electro-hydraulic motor pump unit G to at least the load ports A, B is degradable by leakage, and possibly even to the in Fig. 1 not shown hydraulic consumers.
  • FIG. 2 shows the dash-dotted lines the housing 1 and the housing 7, and a hydraulic load Z (for example, a double-acting differential cylinder), for driving a tool, a clamping device, a holding device, or the like. Via an actuating element 17.
  • the hydraulic load Z is via hydraulic hoses or piping. 8 , 9 connected to the load terminals A, B and 5, 6.
  • the electric motor M is an AC motor that drives its fan 2 and a high-pressure pump stage P1 with a small flow rate as well as a low-pressure pump stage P3 with a larger flow rate, which suck from the tank T.
  • Both pump stages P1, P3 are connected to a common pressure line 10, wherein the low-pressure pump stage P3 via a check valve eleventh hedged and trained as a preconfigured from the pressure line 10 pressure relief valve switching valve 12 with a return line 13 is connectable.
  • the pressure line 10 leads to an input of the directional control valve 3, which is durable by spring force in the switching position shown and switchable by the switching magnet 4 in the other switching position.
  • the consumer port B is connected via a working line 15 to the pressure line 10 (return movement or release stroke), while the consumer port A is connected via a working line 14 to the return line 13 and thus relieved of pressure.
  • Both working lines 14, 15 are each secured via a pressure relief valve R1, R2 to return 13.
  • the hydraulic, automatic pressure relief device D is formed by a built-in pressure relief valve R2 Beipass 16.
  • Both pressure relief valves R1, R2 are seat valves, which seal leak-free in the shut-off position. Thanks to the Beipasses 16 occurs, however, in the shut-off position of the pressure relief valve R2 leakage to the return line 13, through which the system pressure is reduced.
  • the by-pass 16 is sized to produce a leak of between 0.3 and 0.4 liters per minute at 150 bar (e.g., the set pressure of the pressure relief valve R2), thereby reducing the pressure in a few seconds, e.g. about 5 seconds, dismantled.
  • hose or pipe couplings to the hydraulic consumer Z can be easily released or the hydraulic consumer Z can optionally be adjusted by hand.
  • Fig. 3 is a longitudinal section of the add-on element C in a plane in which the switching valve 12 and the pressure relief valve R2 are visible.
  • the pressure limiting valve R2 is installed in a chamber of the housing 7, which intersects the return line 13 and the working line 15.
  • an insert member 18 is positioned, which positions a valve seat 19 between the return 13 and the working line 15.
  • a valve cone 20 cooperates, by a pressure generating spring 21 in the direction of the valve seat 19 and against the Pressure in the working line 15 is charged.
  • the integrated pressure relief device D with the bypass 16 is formed between the valve cone 20 and the valve seat 10, as shown in FIG 4 and 5 is explained.
  • the valve cone 20 has a coaxial shaft 23 for pressing on a spring abutment 22.
  • the small diameter end portion of the poppet 20 is extended by a neck 27 on which a hollow damping piston 28 is disposed.
  • a cavity 29 of the damping piston 28 communicates via a channel 30 with the surroundings of the poppet 20 in communication and contains a ball check valve with a valve ball 31 and a closing spring 32.
  • the lower, open-shaped end of the cavity 29 is closed by a plug 33.
  • the valve cone has a conical surface 25 as a seating surface which cooperates with the valve seat 19 in a seating area 24.
  • a flattening 26 is formed, which forms the Beipass 16 as an interruption of the conical surface 25 with the valve seat 19.
  • the flattening 26 is an area, for example ground, in the conical surface 25, the surface extending at least approximately parallel to the conical generator.
  • a grinding depth Y of about 2 to 5% of the cone shell diameter X in the seating area 24 results in a suitable size of the by-pass.
  • at least one longitudinal notch could also be formed.
  • Fig. 6 shown an alternative embodiment of the pressure relief valve R2, which is designed as a ball seat valve with a valve ball 20 'in cooperation with the valve seat 19'.
  • the bypass 16 is formed by at least one notch or ablation 34 in the valve seat 19 'in cooperation with the spherical surface.
  • the principle of providing a notch in the valve seat 19 'could also be provided with a conical seat valve.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Safety Valves (AREA)

Description

Die Erfindung betrifft ein elektrohydraulisches Motorpumpenaggregat gemäß Oberbegriff des Anspruchs 1.The invention relates to an electrohydraulic motor pump assembly according to the preamble of claim 1.

Elektrohydraulische Motorpumpenaggregate gemäß DE 200 07 554 U werden an Werkzeugmaschinen eingesetzt, um hydromechanische Spann- oder Werkzeug- bzw. Werkstückhaltevorrichtungen zu steuern. Ferner werden elektrohydraulische Motorpumpenaggregate als transportable Versorgungseinheiten für Schneid- oder Nietgeräte, Werkzeuge oder Schrauber benutzt. Das Motorpumpenaggregat ist mit einem Anbauelement ausgestattet, das den wenigstens einen Verbraucheranschluss aufweist, an der der jeweilige Verbraucher, beispielsweise über Hydraulikschläuche oder Verrohrungen, angeschlossen wird. Wegen der hohen Dichtigkeit der Ventilkomponenten und auch der Herstellungspräzision der anschließbaren Hydraulikverbraucher bleibt selbst nach Abschalten des Motorpumpenaggregats noch ein beträchtlicher Systemdruck über längere Zeit aufrecht. Insbesondere bei transportablen elektrohydraulischen Motorpumpenaggregaten mit Wechselmotoren und für Höchstdrücke bis zu 800 bar ist das Druckhaltevermögen ein unter bestimmen Umständen unerwünschter Nachteil der hohen Qualität der zusammenwirkenden hydraulischen Komponenten. Der aufrechtgehaltene Druck erschwert speziell einem Wechselstrommotor das Anlaufen nach einer Betriebsunterbrechung. Ferner sind Schlauch- oder Rohrkupplungen nur mit relativ viel Aufwand zu lösen, und lässt sich der angeschlossene Hydroverbraucher beispielsweise von Hand nicht zurückstellen, obwohl dies aus bestimmten Gründen gerade wünschenswert wäre. Ein hauptsächlicher Grund für dieses Langzeit-Druckhaltevermögen liegt in der weitgehenden Leckagefreiheit der einzelnen Ventilkomponenten in deren Schließstellungen, und insbesondere der vollständigen Leckagefreiheit der Druckbegrenzungsventile in Sitzventilbauweise. Andererseits ist diese Leckagefreiheit für Höchstdrücke bis zu ca. 800 bar ein Muss, um auch mit einem Wechselstrommotor und kleiner Fördermenge der Hochdruckpumpenstufe die notwendigen Arbeitsdrücke zuverlässig und rasch zu erreichen.Electrohydraulic motor pump units according to DE 200 07 554 U are used on machine tools to control hydromechanical chuck or tool holding devices. Furthermore, electro-hydraulic motor pump units are used as transportable supply units for cutting or riveting tools, tools or screwdrivers. The motor pump unit is equipped with an attachment that has the at least one consumer port to which the respective consumer, for example via hydraulic hoses or piping, is connected. Because of the high tightness of the valve components and also the manufacturing precision of the connectable hydraulic consumers even after switching off the motor pump unit still a considerable system pressure for a long time upright. Especially with transportable electrohydraulic motor pump units with changeover motors and for maximum pressures up to 800 bar, the pressure holding capacity is an undesirable disadvantage of the high quality of the cooperating hydraulic components under certain circumstances. The maintained pressure especially makes it difficult for an AC motor to start up after a service interruption. Furthermore, hose or pipe couplings can be solved only with relatively much effort, and can not reset the connected hydraulic consumers, for example, by hand, although this would be desirable for certain reasons. A major reason for this long-term pressure holding capacity is the extensive freedom from leakage of the individual valve components in their closed positions, and in particular the complete absence of leakage of the pressure relief valves in the seat valve design. On the other hand, this freedom from leakage for maximum pressures up to about 800 bar is a must to achieve the necessary working pressures reliably and quickly even with an AC motor and small flow rate of the high-pressure pump stage.

Bei einem aus US-A-4 197 705 bekannten, hydraulischen Steuersystem ist eine extern angetriebene Regelpumpe mit variabler Verdrängung vorgesehen, die als Schrägscheibenpumpe mit Axialkolben ausgebildet ist. In das Gehäuse der Regelpumpe ist ein fluidbetätigter Verdrängungssteuer-Mechanismus eingegliedert, der die Neigung der Schrägscheibe entsprechend der gewünschten Förderleistung einstellt. An die Regelpumpe sind direkt und parallel mehrere Wegeventile angeschlossen. Nur in der Neutralstellung aller Wegeventile ist die Druckseite der Regelpumpe über zentrale Kanäle der Wegeventile mit dem Rücklauf verbunden. Der Verdrängungssteuer-Mechanismus ist gegenüber dem Rücklauf abgesperrt. Dank der Durchlaufkanäle in den Wegeventilen herrscht kein Systemdruck mehr, wenn die Regelpumpe abgeregelt hat und alle Wegeventile in der Neutralstellung stehen.At one off US-A-4,197,705 known, hydraulic control system, an externally driven variable displacement pump is provided, which is designed as a swash plate pump with axial piston. In the housing of the control pump, a fluid-operated displacement control mechanism is incorporated, which adjusts the inclination of the swash plate according to the desired flow rate. To the control pump directly and in parallel several directional control valves are connected. Only in the neutral position of all directional valves, the pressure side of the control pump via central channels of the directional control valves is connected to the return. The displacement control mechanism is shut off from the return. Thanks to the flow channels in the directional control valves, system pressure no longer prevails when the control pump has stopped and all directional control valves are in the neutral position.

Bei einer aus US-A-5 454 223 bekannten, hydraulischen Steuervorrichtung für zwei doppelseitig beaufschlagbare Hydraulikzylinder ist eine Regelpumpe vorgesehen, die förderseitig über eine Versorgungsleitung an ein Wegeventil mit zwei Sektionen angeschlossen ist. Im Wegeventil ist für einen lastabhängigen Vorsteuerdruck ein Begrenzungs-Sitzventil mit einem permanent zum Rücklauf offenen Beipass vorgesehen, um bei nicht betätigten Hydraulikzylindern den Vorsteuerdruck für ein den Druck in der Versorgungsleitung regelndes Ventil in einem Vorsteuerdruckkreis zum Rücklauf abzubauen, damit die Regelpumpe auf minimale Förderleistung abgeregelt wird. Die Regelpumpe wird ständig angetrieben, fördert jedoch bei minimaler Förderleistung nicht.At one off US-A-5,454,223 known, hydraulic control device for two double-sided acted upon hydraulic cylinder, a control pump is provided, which is connected on the delivery side via a supply line to a directional control valve with two sections. In the directional control valve a limit seat valve is provided with a permanently open to the return bypass to reduce the pilot pressure for a pressure in the supply line regulating valve in a pilot pressure circuit to the return at non-actuated hydraulic cylinders, so that the control pump to minimum flow rate becomes. The control pump is constantly driven, but does not deliver at minimum flow rate.

Der Erfindung liegt die Aufgabe zugrunde, ein hydraulisches Motorpumpenaggregat der eingangs genannten Art zu schaffen, bei dem das Langzeit-Druckhaltevermögen der hydraulischen Ventilkomponenten auf baulich einfache Weise beseitigt ist und bei dem Anlaufprobleme beispielsweise eines Wechselstrommotors vermeidbar sind.The invention has for its object to provide a hydraulic motor pump unit of the type mentioned, in which the long-term pressure holding capacity of the hydraulic valve components is eliminated in a structurally simple manner and in the startup problems, for example, an AC motor can be avoided.

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

Die Druckentlastungsvorrichtung im Anbauelement baut selbständig den Druck ab, sobald der Elektromotor steht. Dies erleichtert dem Elektromotor das neuerliche Anlaufen erheblich. Insbesondere bei einem Wechselstrommotor ist diese Wirkung vorteilhaft, weil ein Wechselstrommotor ansonsten einen relativ hohen Anlaufstrom braucht, der gegebenenfalls die Sicherungen des normalen Netzes überlasten könnte. Wechselstrommotoren werden speziell bei transportablen Motorpumpenaggregaten benutzt, damit das Motorpumpenaggregat eben im mobilen Einsatz an das normale Netz angeschlossen werden kann. Jedoch auch bei anderen Elektromotoren kann das leichte Anlaufen wünschenswert sein. Ferner lassen sich nach der Druckentlastung Schlauch- oder Rohrkupplungen problemlos lösen, und lässt sich gegebenenfalls der Verbraucher von Hand zurückstellen, was beispielsweise bei einem unerwarteten Stromausfall vorteilhaft ist. Der permanent offene Beipass bedeutet nur einen vernachlässigbaren Verlust. Für diese Zusatzfunktion wird keine eigene Ventilkomponente benützt, sondern ein ohnedies notwendiges Druckbegrenzungsventil. Das Druckbegrenzungsventil erzeugt trotz der Sitzventilbauweise in der an sich leckagefreien Absperrstellung eine in ihrem Ausmaß vorbestimmte Leckage, die jedoch die Druckbegrenzungsfunktion nicht beeinträchtigt. Bei dem elektrohydraulischen Motorpumpenaggregat mit mindestens zwei Verbraucheranschlüssen sind die beiden Druckbegrenzungsventile auf unterschiedliche Ansprechdrücke eingestellt. Zweckmäßig wird der Beipass im Druckbegrenzungsventil mit dem niedrigeren Ansprechdruck angeordnet, damit zum Erreichen des höheren Arbeitsdrucks keine Verluste in Kauf zu nehmen sind. Bei einem Rückstell- oder Lösehub eines mit dem Motorpumpenaggregat gesteuerten Hydraulikverbrauchers spielt der Verlust durch den Beipass keine Rolle.The pressure relief device in the attachment automatically reduces the pressure as soon as the electric motor stops. This considerably facilitates the restart of the electric motor. In particular, in an AC motor, this effect is advantageous because an AC motor otherwise needs a relatively high starting current, if necessary could overload the fuses of the normal network. AC motors are used especially in portable motor pump units, so that the motor pump unit can be connected to the normal network just in mobile use. However, even with other electric motors, light starting may be desirable. Furthermore, can be solved easily after the pressure relief hose or pipe couplings, and can optionally reset the consumer by hand, which is advantageous, for example, in an unexpected power failure. The permanently open passport means only a negligible loss. For this additional function, no separate valve component is used, but an already necessary pressure relief valve. Despite the seat valve design, the pressure limiting valve generates a predetermined leakage in its degree of leakage-free shut-off position, which, however, does not impair the pressure-limiting function. In the electrohydraulic motor pump unit with at least two consumer connections, the two pressure relief valves are set to different response pressures. The bypass is expediently arranged in the pressure limiting valve with the lower response pressure, so that no losses are to be accepted in order to achieve the higher working pressure. In the case of a reset or release stroke of a hydraulic consumer controlled by the motor pump unit, the loss due to the by-pass does not matter.

Ein Wechselstrommotor als Elektromotor bietet den Vorteil, an das normale Wechselstromnetz angeschlossen werden zu können. Die Zweikreispumpenstufe ermöglicht es, mit der Niederdruckpumpenstufe mit relativ großer Fördermenge zunächst ein niedrigeres Druckniveau zu erreichen, und dann mit der Hochdruckpumpenstufe mit geringer Fördermenge bis auf sehr hohe Arbeitsdrücke zu kommen, z.B. bis auf etwa 800.0,1 MPa (ca. 800 bar). Die Bewegungsrichtungen des Hydraulikverbrauchers werden mittels des Wegesteuerventils gesteuert, wobei jedes Druckbegrenzungsventil den maximalen Arbeitsdruck in einer Bewegungsrichtung überwacht. Um die Druckentlastungsfunktion zu erhalten, ist der Beipass in dem die weniger wichtige Funktion bzw. den niedrigeren Druck überwachenden Druckbegrenzungsventil angeordnet.An AC motor as an electric motor offers the advantage of being able to be connected to the normal AC mains. The two-circuit pump stage makes it possible to first reach a lower pressure level with the relatively high displacement low-pressure pump stage, and then to come to very high working pressures with the low-pressure high-pressure pump stage, e.g. up to about 800.0,1 MPa (about 800 bar). The directions of movement of the hydraulic consumer are controlled by means of the directional control valve, each pressure relief valve monitoring the maximum working pressure in a direction of movement. In order to obtain the pressure relief function, the bypass is arranged in the pressure limiting valve monitoring the less important function or the lower pressure.

Baulich einfach wird der Beipass in einem Kegelsitzventil durch eine Abflachung im Kegelmantel des Ventilkegels gebildet. Die Abflachung formt in der Absperrstellung des Druckbegrenzungsventils mit dem Ventilsitz einen Durchgang bzw. eine Drossel einer vorbestimmten Größe, über den die Leckage abströmt. Zweckmäßig wird die Abflachung durch eine angeschliffene Fläche gebildet, deren Herstellung einfach ist.Structurally simple, the by-pass is formed in a conical seat valve by a flattening in the conical surface of the valve cone. The flattening forms in the shut-off position of the pressure relief valve with the valve seat a passage or a throttle one predetermined size over which the leakage flows. Suitably, the flattening is formed by a sanded surface whose production is simple.

Die Abflachung sollte zur Kegelerzeugenden parallel sein, so dass sie sich bei den Schleifhüben beim Schleifen des Kegelmantels durch Unterbrechen der Drehbewegung des Ventilkegels nur durch Zustellen des Schleifwerkzeuges präzise formen lässt.The flattening should be parallel to the cone-generating, so that it can be precisely formed during grinding of the cone shroud by interrupting the rotational movement of the poppet only by advancing the grinding tool during grinding.

Alternativ könnte bei einem Kegel- oder Kugelsitzventil der Beipass durch wenigstens eine Kerbe im Ventilsitz geformt sein.Alternatively, in a cone or ball seat valve, the by-pass could be formed by at least one notch in the valve seat.

Zweckmäßig ist der Beipass so bemessen, dass er eine Leckage von ca. 0,3 bis 0,4.60.10-3m3/s (ca. 0,3 bis 0,4 Liter pro Minute) bei 150.0,1 MPa (150 bar) erzeugt. Dadurch lässt sich eine zumindest weitestgehende Druckentlastung beispielsweise innerhalb von wenigen Sekunden, z. B. ca. 5 Sekunden, herbeiführen.The bypass is expediently designed to have a leakage of about 0.3 to 0.4.60.10 -3 m 3 / s (about 0.3 to 0.4 liters per minute) at 150.0.1 MPa (150 bar). This can be at least as far as possible pressure relief, for example, within a few seconds, z. B. about 5 seconds, bring about.

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

Fig. 1
eine schematische Seitenansicht eines elektrohydraulischen Motorpumpenaggregats,
Fig. 2
das elektrohydraulische Motorpumpenaggregat symbolisiert durch ein Blockschaltbild, das auch einen Hydraulikverbraucher zeigt,
Fig. 3
einen Längsschnitt eines Anbauelements des Motorpumpenaggregats,
Fig. 4
ein Detail aus Fig. 3, teilweise im Schnitt,
Fig. 5
ein Detail zu Fig. 4, und
Fig. 6
einen Längsschnitt einer anderen Ausführungsform eines Anbauelements.
Reference to the drawings, embodiments of the subject invention will be explained. Show it:
Fig. 1
a schematic side view of an electro-hydraulic motor pump unit,
Fig. 2
the electro-hydraulic motor pump unit symbolizes by a block diagram, which also shows a hydraulic consumer,
Fig. 3
a longitudinal section of an add-on element of the motor pump unit,
Fig. 4
a detail from Fig. 3 , partly in section,
Fig. 5
a detail too Fig. 4 , and
Fig. 6
a longitudinal section of another embodiment of an attachment.

Alternativ könnte bei einem Kegel- oder Kugelsitzventil der Beipass durch wenigstens eine Kerbe im Ventilsitz geformt sein.Alternatively, in a cone or ball seat valve, the by-pass could be formed by at least one notch in the valve seat.

Zweckmäßig ist der Beipass so bemessen, dass er eine Leckage von ca. 0,3 bis 0,4 Liter pro Minute bei 150 bar erzeugt. Dadurch lässt sich eine zumindest weitestgehende Druckentlastung beispielsweise innerhalb von wenigen Sekunden, z.B. ca. 5 Sekunden, herbeiführen.Suitably, the bypass is sized so that it produces a leakage of about 0.3 to 0.4 liters per minute at 150 bar. As a result, at least a great deal of pressure relief can be achieved, for example, within a few seconds, e.g. about 5 seconds, bring about.

Günstig ist es, den Ventilkegel mit einem Dämpfungskolben auszubilden, um ein nervöses Ansprechverhalten des Druckbegrenzungsventils zu vermeiden.It is advantageous to form the valve cone with a damping piston to avoid a nervous response of the pressure relief valve.

Die Dämpfungswirkung wird verstärkt, wenn der Hohlraum des Dämpfungskolbens über wenigstens einen Kanal nach außen offen ist und ein Rückschlagventil enthält.The damping effect is enhanced when the cavity of the damping piston is open to the outside via at least one channel and contains a check valve.

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

Fig. 1
eine schematische Seitenansicht eines elektrohydraulischen Motorpumpenaggregats,
Fig. 2
das elektrohydraulische Motorpumpenaggregat symbolisiert durch ein Blockschaltbild, das auch einen Hydraulikverbraucher zeigt,
Fig. 3
einen Längsschnitt eines Anbauelements des Motorpumpenaggregats,
Fig. 4
ein Detail aus Fig. 3, teilweise im Schnitt,
Fig. 5
ein Detail zu Fig. 4, und
Fig. 6
einen Längsschnitt einer anderen Ausführungsform eines Anbauelements.
Reference to the drawings, embodiments of the subject invention will be explained. Show it:
Fig. 1
a schematic side view of an electro-hydraulic motor pump unit,
Fig. 2
the electro-hydraulic motor pump unit symbolizes by a block diagram, which also shows a hydraulic consumer,
Fig. 3
a longitudinal section of an add-on element of the motor pump unit,
Fig. 4
a detail from Fig. 3 , partly in section,
Fig. 5
a detail too Fig. 4 , and
Fig. 6
a longitudinal section of another embodiment of an attachment.

Ein elektrohydraulisches Motorpumpenaggregat G (Fig. 1) wird als Versorgungseinheit z.B. eines hydromechanischen Werkzeugs entweder stationär eingebaut oder als transportable Einheit eingesetzt. In einem Gehäuse 1, das gleichzeitig ein Ölreservoir T bilden kann, ist ein Elektromotor M mit einem Lüfter 2 als Antriebs wenigstens einer innenliegenden Pumpenstufe P vorgesehen. Der Elektromotor M kann ein Drehstrommotor, ein Gleichstrommotor oder auch, insbesondere für mobile Einsatzzwecke, ein aus dem normalen Netz versorgbarer Wechselstrommotor sein.An electrohydraulic motor pump unit G ( Fig. 1 ) is installed as a supply unit, for example, a hydromechanical tool either stationary or used as a transportable unit. In a housing 1, which can form an oil reservoir T at the same time, an electric motor M with a fan 2 is provided as a drive of at least one pump stage P inside. The electric motor M can be a three-phase motor, a DC motor or, in particular for mobile applications, an AC motor that can be supplied from the normal network.

Ein Anbauelement C ist an das Gehäuse 1 angebaut oder in dieses integriert und steht mit wenigstens einem, nicht gezeigten, Druckseitenanschluss der Pumpenstufe P in Verbindung, und auch mit dem in das Gehäuse 1 führenden Rücklauf. Das Anbauelement C weist in Fig. 1 ein blockartiges Gehäuse 7 auf, an dem ein Wegesteuerventil 3 mit einem Schaltmagneten 4 angebracht ist. Am Anbauelement C sind ein oder zwei oder mehr Verbraucheranschlüsse A, B bzw. 5, 6 vorgesehen. Dem Verbraucheranschluss B bzw. 6 ist, vorzugsweise im Anbauelement C, eine hydraulische, selbsttätige Druckentlastungsvorrichtung D zugeordnet, über die bei abgeschaltetem Elektromotor M der Systemdruck, zumindest im elektrohydraulischen Motorpumpenaggregat G bis zumindest den Verbraucheranschlüssen A, B durch Leckage abbaubar ist, und gegebenenfalls sogar bis in den in Fig. 1 nicht gezeigten Hydraulikverbraucher.An attachment C is attached to the housing 1 or integrated into this and communicates with at least one, not shown, pressure side port of the pump stage P in conjunction, and also with the leading into the housing 1 return. The add-on element C points in Fig. 1 a block-like housing 7, on which a directional control valve 3 is mounted with a solenoid 4. On attachment C one or two or more consumer terminals A, B and 5, 6 are provided. The consumer port B or 6 is, preferably in the add-on element C, a hydraulic, automatic pressure relief device D assigned via the switched off electric motor M, the system pressure, at least in the electro-hydraulic motor pump unit G to at least the load ports A, B is degradable by leakage, and possibly even to the in Fig. 1 not shown hydraulic consumers.

Das Blockschaltbild der Fig. 2 zeigt strichpunktiert das Gehäuse 1 und das Gehäuse 7, sowie einen Hydraulikverbraucher Z (beispielsweise einen doppelseitig beaufschlagbaren Differentialzylinder), zum Antreiben eines Werkzeugs, einer Spannvorrichtung, einer Haltevorrichtung, oder dgl. über ein Betätigungselement 17. Der Hydraulikverbraucher Z ist über Hydraulikschläuche oder Verrohrungen 8, 9 an den Verbraucheranschlüssen A, B bzw. 5, 6 angeschlossen.The block diagram of Fig. 2 shows the dash-dotted lines the housing 1 and the housing 7, and a hydraulic load Z (for example, a double-acting differential cylinder), for driving a tool, a clamping device, a holding device, or the like. Via an actuating element 17. The hydraulic load Z is via hydraulic hoses or piping. 8 , 9 connected to the load terminals A, B and 5, 6.

Es sei angenommen, dass der Elektromotor M ein Wechselstrommotor ist, der seinen Lüfter 2 sowie eine Hochdruckpumpenstufe P1 mit kleiner Fördermenge als auch eine Niederdruckpumpenstufe P3 mit größerer Fördermenge antreibt, die aus dem Tank T ansaugen. Beide Pumpenstufen P1, P3 sind an eine gemeinsame Druckleitung 10 angeschlossen, wobei die Niederdruckpumpenstufe P3 über ein Rückschlagventil 11 abgesichert und über ein als aus der Druckleitung 10 vorgesteuertes Druckbegrenzungsventil ausgebildetes Umschaltventil 12 mit einem Rücklauf 13 verbindbar ist. Die Druckleitung 10 führt zu einem Eingang des Wegesteuerventils 3, das durch Federkraft in der gezeigten Schaltstellung haltbar und durch den Schaltmagneten 4 in die andere Schaltstellung umstellbar ist. In der gezeigten Schaltstellung ist der Verbraucheranschluss B über eine Arbeitsleitung 15 mit der Druckleitung 10 verbunden (Rückstellbewegung oder Lösehub), während der Verbraucheranschluss A über eine Arbeitsleitung 14 mit dem Rücklauf 13 verbunden und damit druckentlastet ist. Beide Arbeitsleitungen 14, 15 sind über je ein Druckbegrenzungsventil R1, R2 zum Rücklauf 13 abgesichert. Die hydraulische, selbsttätige Druckentlastungsvorrichtung D wird durch einen in das Druckbegrenzungsventil R2 integrierten Beipass 16 gebildet. Beide Druckbegrenzungsventile R1, R2 sind Sitzventile, die an sich in der Absperrstellung leckagefrei abdichten. Dank des Beipasses 16 tritt jedoch in der Absperrstellung des Druckbegrenzungsventils R2 Leckage zum Rücklauf 13 auf, durch die der Systemdruck abgebaut wird.It is assumed that the electric motor M is an AC motor that drives its fan 2 and a high-pressure pump stage P1 with a small flow rate as well as a low-pressure pump stage P3 with a larger flow rate, which suck from the tank T. Both pump stages P1, P3 are connected to a common pressure line 10, wherein the low-pressure pump stage P3 via a check valve eleventh hedged and trained as a preconfigured from the pressure line 10 pressure relief valve switching valve 12 with a return line 13 is connectable. The pressure line 10 leads to an input of the directional control valve 3, which is durable by spring force in the switching position shown and switchable by the switching magnet 4 in the other switching position. In the switching position shown, the consumer port B is connected via a working line 15 to the pressure line 10 (return movement or release stroke), while the consumer port A is connected via a working line 14 to the return line 13 and thus relieved of pressure. Both working lines 14, 15 are each secured via a pressure relief valve R1, R2 to return 13. The hydraulic, automatic pressure relief device D is formed by a built-in pressure relief valve R2 Beipass 16. Both pressure relief valves R1, R2 are seat valves, which seal leak-free in the shut-off position. Thanks to the Beipasses 16 occurs, however, in the shut-off position of the pressure relief valve R2 leakage to the return line 13, through which the system pressure is reduced.

Der Beipass 16 ist beispielsweise so bemessen, dass er bei 150 bar (z.B. dem Ansprechdruck des Druckbegrenzungsventils R2) eine Leckage zwischen 0,3 und 0,4 Liter pro Minute erzeugt, durch die der Druck beispielsweise in wenigen Sekunden, z.B. ca. 5 Sekunden, abgebaut wird.By way of example, the by-pass 16 is sized to produce a leak of between 0.3 and 0.4 liters per minute at 150 bar (e.g., the set pressure of the pressure relief valve R2), thereby reducing the pressure in a few seconds, e.g. about 5 seconds, dismantled.

Der auf diese Weise bei Anhalten des Elektromotors M auftretende Druckabbau erleichtert dem Elektromotor M das spätere Anlaufen. Ferner lassen sich Schlauch- oder Rohrkupplungen zum Hydraulikverbraucher Z leicht lösen bzw. lässt sich der Hydraulikverbraucher Z gegebenenfalls von Hand verstellen.The pressure reduction occurring in this way when stopping the electric motor M facilitates the subsequent startup of the electric motor M. Furthermore, hose or pipe couplings to the hydraulic consumer Z can be easily released or the hydraulic consumer Z can optionally be adjusted by hand.

Fig. 3 ist ein Längsschnitt des Anbauelements C in einer Ebene, in der das Umschaltventil 12 und das Druckbegrenzungsventil R2 sichtbar sind. Das Druckbegrenzungsventil R2 ist in eine Kammer des Gehäuses 7 eingebaut, die den Rücklauf 13 und die Arbeitsleitung 15 schneidet. In der Kammer ist ein Einsatzelement 18 positioniert, das einen Ventilsitz 19 zwischen dem Rücklauf 13 und der Arbeitsleitung 15 positioniert. Mit dem Ventilsitz 19 arbeitet ein Ventilkegel 20 zusammen, der durch eine den Ansprechdruck erzeugende Feder 21 in Richtung auf den Ventilsitz 19 und gegen den Druck in der Arbeitsleitung 15 belastet wird. Die integrierte Druckentlastungsvorrichtung D mit dem Beipass 16 wird zwischen dem Ventilkegel 20 und dem Ventilsitz 10 gebildet, wie dies anhand der Fig. 4 und 5 erläutert wird. Fig. 3 is a longitudinal section of the add-on element C in a plane in which the switching valve 12 and the pressure relief valve R2 are visible. The pressure limiting valve R2 is installed in a chamber of the housing 7, which intersects the return line 13 and the working line 15. In the chamber, an insert member 18 is positioned, which positions a valve seat 19 between the return 13 and the working line 15. With the valve seat 19, a valve cone 20 cooperates, by a pressure generating spring 21 in the direction of the valve seat 19 and against the Pressure in the working line 15 is charged. The integrated pressure relief device D with the bypass 16 is formed between the valve cone 20 and the valve seat 10, as shown in FIG 4 and 5 is explained.

Gemäß Fig. 4 weist der Ventilkegel 20 z.B. am großdurchmessrigen Ende einen koaxialen Schaft 23 zum Aufpressen eines Federwiderlagers 22 auf. Der kleindurchmessrige Endabschnitt des Ventilkegels 20 wird durch einen Hals 27 verlängert, an dem ein hohler Dämpfungskolben 28 angeordnet ist. Ein Hohlraum 29 des Dämpfungskolbens 28 steht über einen Kanal 30 mit der Umgebung des Ventilkegels 20 in Verbindung und enthält ein Kugelrückschlagventil mit einer Ventilkugel 31 und einer Schließfeder 32. Das untere, offen geformte Ende des Hohlraums 29 ist durch einen Stopfen 33 verschlossen.According to Fig. 4 For example, at the large-diameter end, the valve cone 20 has a coaxial shaft 23 for pressing on a spring abutment 22. The small diameter end portion of the poppet 20 is extended by a neck 27 on which a hollow damping piston 28 is disposed. A cavity 29 of the damping piston 28 communicates via a channel 30 with the surroundings of the poppet 20 in communication and contains a ball check valve with a valve ball 31 and a closing spring 32. The lower, open-shaped end of the cavity 29 is closed by a plug 33.

Der Ventilkegel hat einen Kegelmantel 25 als Sitzfläche, der in einem Sitzbereich 24 mit dem Ventilsitz 19 zusammenarbeitet. Im Kegelmantel 25 ist eine Abflachung 26 geformt, die als Unterbrechung des Kegelmantels 25 mit dem Ventilsitz 19 den Beipass 16 bildet.The valve cone has a conical surface 25 as a seating surface which cooperates with the valve seat 19 in a seating area 24. In the conical surface 25 a flattening 26 is formed, which forms the Beipass 16 as an interruption of the conical surface 25 with the valve seat 19.

Gemäß Fig. 5 ist die Abflachung 26 eine beispielsweise geschliffene Fläche im Kegelmantel 25, wobei sich die Fläche zumindest in etwa parallel zur Kegelerzeugenden erstreckt. Eine Schleiftiefe Y von ca. 2 bis 5 % des Kegelmanteldurchmesser X im Sitzbereich 24 ergibt eine passende Größe des Beipasses. Alternativ könnte anstelle der Abflachung 26 auch wenigstens eine längsverlaufende Kerbe eingeformt sein.According to Fig. 5 For example, the flattening 26 is an area, for example ground, in the conical surface 25, the surface extending at least approximately parallel to the conical generator. A grinding depth Y of about 2 to 5% of the cone shell diameter X in the seating area 24 results in a suitable size of the by-pass. Alternatively, instead of the flattening 26, at least one longitudinal notch could also be formed.

In Fig. 6 ist eine alternative Ausführungsform des Druckbegrenzungsventils R2 gezeigt, das als Kugelsitzventil mit einer Ventilkugel 20' in Zusammenarbeit mit dem Ventilsitz 19' ausgebildet ist. Bei dieser Ausführungsform wird der Beipass 16 durch wenigstens eine Kerbe oder Abtragung 34 im Ventilsitz 19' bei Zusammenarbeit mit der Kugeloberfläche gebildet. Das Prinzip, im Ventilsitz 19' eine Kerbe vorzusehen, könnte auch bei einem Kegelsitzventil vorgesehen sein.In Fig. 6 shown an alternative embodiment of the pressure relief valve R2, which is designed as a ball seat valve with a valve ball 20 'in cooperation with the valve seat 19'. In this embodiment, the bypass 16 is formed by at least one notch or ablation 34 in the valve seat 19 'in cooperation with the spherical surface. The principle of providing a notch in the valve seat 19 'could also be provided with a conical seat valve.

Claims (7)

  1. Electrohydraulic motor pump aggregate (G), comprising a housing (1) forming an oil reservoir (T) in which an electromotor (M) drives at least one pump stage (P, P1, P3), an attachment element (C) attached to or integrated in the housing (1) between at least one pressure side port of the pump stage and an aggregate oil return line (13) and at least one consumer port (A, 5), a directional control valve (3) between the consumer port and the pressure side port, and at least one pressure limiting valve (R1, R2) constructed as a seated valve between the consumer port and the aggregate oil return line (13), characterised in that the motor pump aggregate (G) comprises two consumer ports (A, B, 5, 6)and two pressure limiting valves (R1, R2) adjusted for differing response pressures, and that a by-pass (16) is provided in the pressure limiting valve (R2) for the lower response pressure which by-pass (16) is permanently open even in a closed condition of the pressure limiting valve (R2) to define an automatic hydraulic pressure releasing device (D).
  2. Electrohydraulic motor pump aggregate as in claim 1, characterised in that the by-pass (16) is provided in the pressure limiting valve (R2) associated to the consumer port (B, 6) intended for a return stroke or a release stroke of a double-sided actuable hydraulic consumer (Z) connected to the consumer ports (A, B, 5, 6).
  3. Electrohydraulic motor pump aggregate as in claim 1, characterised in that the motor pump aggregate (G) contains an AC-motor as the electromotor (M) which AC-motor drives a dual circuit pump stage comprising at least one high pressure pump stage (P1) and at least one low pressure pump stage (P3), the low pressure pump stage (P3) of which is connected via a switch-over valve (12) to the oil return line (13), and that the system pressure limiting valve (R2) having the by-pass (16) is provided between the directional control valve (3) located downstream of the switching-over valve (12) and the one consumer port (B, 6).
  4. Electrohydraulic motor pump aggregate as in claim 1, characterised in that the system pressure limiting valve (R2) is a seated cone valve having a spring loaded valve cone (20) and a valve seat (19), preferably of conical shape, and that the by-pass (16) is formed by a flat surface (26) in the cone jacket (25) of the valve cone (20).
  5. Electrohydraulic motor pump aggregate as in claim 4, characterised in that the flat surface (26) is a ground surface parallel to the generatrice of the cone with a grinding depth (Y) of about 2% to 5% of the diameter (X) of the cone jacket in a seat zone (24) of the valve cone (20).
  6. Electrohydraulic motor pump aggregate as in claim 3, characterised in that the system pressure limiting valve (R2) is a seated cone valve or a seated ball valve, the valve cone (20) or valve ball (21) of which is pressed by spring load against a valve seat (19, 19'), and that the by-pass (16) is formed by at least one notch (34) in the valve seat (19').
  7. Electrohydraulic motor pump aggregate as in claim 1, characterised in that said by-pass (16) is dimensioned to provide a leakage of 0.3 to 0.4 x 60 x 10-3m3/s (about 0.3 to 0.4 litre per minute) at a pressure of 150 x 0.1 MPa (150 bar), ,preferably for achieving an essentially complete pressure release within about 5 seconds.
EP02010499A 2001-10-15 2002-05-08 Electro-hydraulic motor pump unit and check valve unit Expired - Fee Related EP1302663B1 (en)

Applications Claiming Priority (2)

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DE20116921U DE20116921U1 (en) 2001-10-15 2001-10-15 Electro-hydraulic motor pump unit, add-on element and pressure relief valve
DE20116921U 2001-10-15

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EP1302663A1 EP1302663A1 (en) 2003-04-16
EP1302663B1 true EP1302663B1 (en) 2008-10-08

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US (1) US6739129B2 (en)
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DE (2) DE20116921U1 (en)
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WO2010028100A1 (en) 2008-09-03 2010-03-11 Parker Hannifin Corporation Velocity control of unbalanced hydraulic actuator subjected to over-center load conditions
JP5666233B2 (en) * 2010-10-08 2015-02-12 ナブテスコ株式会社 Aircraft actuator hydraulic system
CO6280066A1 (en) * 2010-10-21 2011-05-20 Serinpet Ltda HYDRAULIC UNIT OF MECHANICAL PUMPING WITH ONE MOTOR
EP2642122B1 (en) * 2012-03-21 2014-05-21 HAWE Hydraulik SE Pump power unit
CN103363163B (en) * 2012-03-27 2015-06-17 上海英威腾工业技术有限公司 Decompression valve for electro-hydraulic servo injection modeling machine
EP2799713B1 (en) * 2013-05-03 2020-09-09 HAWE Hydraulik SE Motor pump unit
MY187080A (en) * 2014-11-19 2021-08-29 Serinpet Representaciones Y Servicios De Petroleos Mechanical hydraulic pumping unit with a radiator integrated
US11958177B2 (en) * 2018-09-07 2024-04-16 Milwaukee Electric Tool Corporation Hydraulic piston pump for a hydraulic tool
JP1663520S (en) * 2019-07-29 2020-07-13
USD924938S1 (en) 2019-07-29 2021-07-13 Hawe Hydraulik Se Housing portion for a hydraulic pump
JP1663497S (en) * 2019-07-29 2020-07-13

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US4197705A (en) * 1978-05-30 1980-04-15 General Signal Corporation Hydraulic control system
GB2050646B (en) * 1979-06-15 1983-04-13 Sperry Rand Corp Hydraulic actuator controls
US4694649A (en) * 1983-02-04 1987-09-22 Howeth David F Pressure limiting acceleration control system and valve for hydraulic motors
US5454223A (en) * 1993-05-28 1995-10-03 Dana Corporation Hydraulic load sensing system with poppet valve having an orifice therein
DE20007554U1 (en) * 2000-04-26 2000-08-10 Heilmeier & Weinlein Motor pump unit

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US6739129B2 (en) 2004-05-25
US20030070428A1 (en) 2003-04-17
EP1302663A1 (en) 2003-04-16
ES2314009T3 (en) 2009-03-16
DE20116921U1 (en) 2002-01-03
DE50212860D1 (en) 2008-11-20

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